MRO Feature Parameter Description

MRO Fe Feature Pa Parameter De Description

http://localhost:7890/pages/GEE01221/07/GEE01221/07/resources/en-u...

eRAN

MRO Feature Parameter Description Issue

03

Date

2015-10-30

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2015. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd.

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Website:

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Email:

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Contents 1 About This Document 1.1 Scope


1.2 Intended Audience 1.3 Change History 1.4 Differences Between eNodeB Types

2 Overview 3 Intra-RAT MRO 3.1 Handover Scenario Identification 3.1.1 Premature Handover 3.1.2 Delayed Handover 3.1.3 Handover to a Wrong Cell 3.1.4 Ping-Pong Handover 3.1.5 Coverage-induced Abnormal Handovers 3.2 Handover Scenario Handling 3.2.1 MRO Against Premature or Delayed Handovers 3.2.1.1 Intra-Frequency MRO 3.2.1.2 Inter-Frequency MRO 3.2.2 MRO Against Handovers to a Wrong Cell 3.2.3 MRO Against Ping-Pong Handovers 3.2.3.1 Cell-Level MRO 3.2.3.2 UE-Level MRO 3.2.4 CIO Value Range Constraints 3.3 Result Monitoring 3.3.1 Parameter Setting Rollback 3.3.2 Penalty on Ping-Pong Parameter Adjustments

4 Inter-RAT MRO 4.1 Handover Scenario Identification 4.1.1 Premature Handover 4.1.2 Delayed Handover 4.1.3 Unnecessary Handover 4.1.4 Ping-Pong Handover 4.2 Handover Scenario Handling 4.2.1 MRO Against Premature Handovers 4.2.2 MRO Against A2-related Delayed Handovers 4.2.3 MRO Against B1-related Delayed Handovers 4.2.4 MRO Against B2-related Delayed Handovers 4.2.5 MRO Against Unnecessary Handovers 4.2.6 MRO Against Ping-Pong Handovers 4.3 Result Monitoring

5 Related Features 6 Network Impact 7 Engineering Guidelines for Intra-RAT MRO 7.1 When to Use Intra-RAT MRO 7.1.1 Intra-Frequency MRO 7.1.2 Inter-Frequency MRO 7.1.3 UE-Level MRO 7.2 Required Information 7.3 Planning 7.3.1 RF Planning 7.3.2 Network Planning 7.3.3 Hardware Planning 7.4 Deployment 7.4.1 Requirements 7.4.2 Data Preparation 7.4.3 Activation 7.4.4 Activation Observation 7.4.4.1 Intra-Frequency MRO 7.4.4.2 Inter-Frequency MRO 7.4.4.3 UE-Level MRO 7.4.5 Deactivation 7.5 Performance Monitoring 7.5.1 Intra-Frequency MRO 7.5.2 Inter-Frequency MRO 7.5.3 UE-Level MRO 7.6 Parameter Optimization 7.6.1 Intra-Frequency MRO 7.6.2 Inter-Frequency MRO 7.6.3 UE-Level MRO 7.7 Troubleshooting

8 Engineering Guidelines for Inter-RAT MRO 8.1 When to Use Inter-RA Inter-RAT T MRO 8.2 Required Information



1.2 Intended Audience 1.3 Change History 1.4 Differences Between eNodeB Types

2 Overview 3 Intra-RAT MRO 3.1 Handover Scenario Identification 3.1.1 Premature Handover 3.1.2 Delayed Handover 3.1.3 Handover to a Wrong Cell 3.1.4 Ping-Pong Handover 3.1.5 Coverage-induced Abnormal Handovers 3.2 Handover Scenario Handling 3.2.1 MRO Against Premature or Delayed Handovers 3.2.1.1 Intra-Frequency MRO 3.2.1.2 Inter-Frequency MRO 3.2.2 MRO Against Handovers to a Wrong Cell 3.2.3 MRO Against Ping-Pong Handovers 3.2.3.1 Cell-Level MRO 3.2.3.2 UE-Level MRO 3.2.4 CIO Value Range Constraints 3.3 Result Monitoring 3.3.1 Parameter Setting Rollback 3.3.2 Penalty on Ping-Pong Parameter Adjustments

4 Inter-RAT MRO 4.1 Handover Scenario Identification 4.1.1 Premature Handover 4.1.2 Delayed Handover 4.1.3 Unnecessary Handover 4.1.4 Ping-Pong Handover 4.2 Handover Scenario Handling 4.2.1 MRO Against Premature Handovers 4.2.2 MRO Against A2-related Delayed Handovers 4.2.3 MRO Against B1-related Delayed Handovers 4.2.4 MRO Against B2-related Delayed Handovers 4.2.5 MRO Against Unnecessary Handovers 4.2.6 MRO Against Ping-Pong Handovers 4.3 Result Monitoring

5 Related Features 6 Network Impact 7 Engineering Guidelines for Intra-RAT MRO 7.1 When to Use Intra-RAT MRO 7.1.1 Intra-Frequency MRO 7.1.2 Inter-Frequency MRO 7.1.3 UE-Level MRO 7.2 Required Information 7.3 Planning 7.3.1 RF Planning 7.3.2 Network Planning 7.3.3 Hardware Planning 7.4 Deployment 7.4.1 Requirements 7.4.2 Data Preparation 7.4.3 Activation 7.4.4 Activation Observation 7.4.4.1 Intra-Frequency MRO 7.4.4.2 Inter-Frequency MRO 7.4.4.3 UE-Level MRO 7.4.5 Deactivation 7.5 Performance Monitoring 7.5.1 Intra-Frequency MRO 7.5.2 Inter-Frequency MRO 7.5.3 UE-Level MRO 7.6 Parameter Optimization 7.6.1 Intra-Frequency MRO 7.6.2 Inter-Frequency MRO 7.6.3 UE-Level MRO 7.7 Troubleshooting

8 Engineering Guidelines for Inter-RAT MRO 8.1 When to Use Inter-RA Inter-RAT T MRO 8.2 Required Information




8.3 Planning 8.3.1 RF Planning 8.3.2 Network Planning 8.3.3 Hardware Planning 8.4 Deployment 8.4.1 Requirements 8.4.2 Data Preparation 8.4.3 Activation 8.4.4 Activation Observation 8.4.5 Deactivation 8.5 Performance Monitoring 8.6 Parameter Optimization 8.7 Troubleshooting

9 Parameters 10 Counters 11 Glossary 12 Reference Documents

1 About This Document 1.1 Scope This document describes LOFD-002005 LOFD-002005 Mobility Robust Optimization (MRO), including its technical principles, related features, features, network impact, and engineering engineering guidelines. Any managed objects (MOs), (MOs), parameters, parameters, alarms, or counters described described below correspond correspond to the software release release delivered with this document. document. Any future updates updates will be described in the product documentation delivered with the latest software release. This document applies only to LTE FDD. Any "LTE" in this document refers to LTE FDD, and "eNodeB" refers to LTE FDD eNodeB. This document applies to the following types of eNodeBs. eNodeB Type

Model

Macro

3900 series eNodeB

Micro

BTS3202E

LampSite

DBS3900

1.2 Intended Audience This document is intended for personnel who: Need to understand the features described herein Work with Huawei products

1.3 Change History This section provides information about the changes in different document versions. There are two types of changes: Feature change Changes in features and parameters of a specified version as well as the affected entities Editorial change Changes in wording or addition of information and any related parameters affected by editorial changes. Editorial change does not specify the affected entities.

eRAN8.1 03 (2015-10-30) This issue includes the following changes. Change Type

Change Description

Parameter Change

Affected Entity

Feature change

None

None

N/A

Editori Editorial al chang change e

Modifi Modified ed the the reco recomme mmende nded d value values s for for the CIO CIO adjust adjustme ment nt rang range. e. For For deta details, ils, see 7.4.2 Data Preparation. Preparation .

None

-

Parameter Change

Affected Entity

eRAN8.1 02 (2015-04-30) This issue includes the following changes. Change Type

Change Description

Featur Feature e chang change e

Added Added the cell-l cell-leve evell MRO MRO funct function ion.. For For detail details, s, see see the the foll followi owing ng sect section ions: s: 3.2.1.1 Intra-Frequency MRO

Added the following parameters: parameters:

N/A

eNBCellRsvdPara. eNBCellRsvdPara.RsvdSwPara2

7.4.2 Data Preparation 7.4.3 Activation 7.4.5 Deactivation 8.4.2 Data Preparation 8.4.3 Activation 8.4.5 Deactivation Editorial change

Revised descriptions in this document.

eRAN8.1 01 (2015-03-23) This issue includes the following changes.

None

-



Change Type

Change Description

Parameter Change

Affected Entity

Feature change

None

None

N/A

Editorial change

Revised descriptions in this document.

Added the following parameters:

-

INTERRATHOCOMMGROUP .UtranB2Thd1Rsrp INTERRATHOCOMMGROUP .GeranB2Thd1Rsrp INTERRATHOUTRANGROUP .InterRatHoUtranB1ThdRscp

eRAN8.1 Draft A (2015-01-15) Compared with Issue 02 (2014-09-30) of eRAN7.0, Draft A (2015-01-15) (2015-01-15) of eRAN8.1 inc ludes the following changes. Change Type

Change Description

Parameter Change

Featur Feature e chang change e

Added Added the configu configurab rable le thre thresho shold ld for for the time time when when a UE stays stays in in a targ target et cell cell during intra-RAT MRO. For details, see the following sections:

Affected Entity

Added the following parameter: parameter:

N/A

MRO. MRO.IntraRatHoTooEarlyTimeThd

3.1.1 Premature Handover 3.1.3 Handover to a Wrong Cell Added the support of UEs complying with 3GPP Release Release 9 for identifying coverage exceptions in intra-RAT MRO and optimized the original coverage exception identification method. For details, see the following sections:

None

N/A

Added the following parameters: parameters:

N/A

3.1.5 Coverage-induced Abnormal Handovers 3.2 Handover Scenario Handling Added intra-RAT intra-RAT MRO enhancement. enhancement. For details, see the following following sections: 3 Intra-RAT MRO

CellMro. CellMro.InterFreqMroAdjParaSel

5 Related Features

MRO. MRO.InterFreqA2RollBackPeriod

6 Network Impact 7 Engineering Guidelines for Intra-RA Intra-RAT T MRO Added descriptions about inter-RA inter-RAT T MRO enhancement. enhancement. For details, see the following sections: 4 Inter-RAT MRO

Modified the following parameter:

N/A

ENodeBAlgoSwitch . MroS MroS witch Added the following parameters: parameters:

8 Engineering Guidelines for Inter-RA Inter-RAT T MRO

MRO. MRO.UnnecInterRatHoRatioThd MRO. MRO.UnnecInterRatHoRsrpThd MRO. MRO.UnnecInterRatHoMeasTime MRO. MRO.InterRatAbnormalHoRatioThd MRO. MRO.InterRatMea InterRatMeasTooLateHoThd sTooLateHoThd MRO. MRO.UnnecInterRatHoOptThd

Optimized descriptions about scenarios of premature and delayed inter-RAT handovers. For details, see the following sections:

None

N/A

None

N/A

None

-

4.1.1 Premature Handover 4.1.2 Delayed Handover Added descriptions about events events A5- and B2-based MRO. For details, see the following sections: 3 Intra-RAT MRO 3.1.2 Delayed Handover 3.2.1.2 Inter-Frequency MRO 4 Inter-RAT MRO 4.2.4 MRO Against B2-related Delayed Handovers Editorial change

Optimized the document structure and descriptions.

1.4 Differences Between eNodeB Types Feature Support by Macro, Micro, and LampSite eNodeBs Feature ID

Description

Supported by Macro eNodeBs

Supported by Micro Supported by LampSite eNodeBs eNodeBs

LOFD-002005

Mobility Robust Optimization (MRO)

Yes

Yes

Yes

Function Implementation in Macro, Micro, and LampSite eNodeBs Function

Difference

Intra-site Intra-site neighborin neighboring g cell cell

Micro eNodeBs eNodeBs do not support support intraintra-site site neighborin neighboring g cells. cells. In In this this docume document, nt, descriptio descriptions ns about about intra-site intra-site neighborin neighboring g cells cells apply apply only to macro macro and LampSite eNodeBs.

2 Overview As mobile telecommunications technologies technologies advance, networks continue continue to grow and incorporate incorporate multiple radio access access technologies (RAT (RATs), resulting in complicated network network maintenance. To To simplify maintenance, an LTE system must support self-organizing network (SON) technologies. Mobility robustness optimization (MRO) is used for self-optimization in an SON. MRO collects handover performance statistics in different scenarios, identifies abnormal handover scenarios, and optimizes the handover-related parameter settings. MRO helps to reduce abnormal radio link failures (RLFs) caused by premature and delayed handovers, intra-RAT intra-RAT handovers to wrong cells , unnecessary inter-RAT handovers, or ping-pong handovers to achieve better resource utilization and improve user experience. In addition, the eNodeB can check coverage to identify abnormal handovers that are not caused by inapp ropriate handover parameter settings, thereby preventing incorrect MRO adjustment.

MRO Feature Parameter Description


To adapt to different networking modes, MRO is classified into intra-RAT MRO and inter-RAT MRO. Intra-RAT MRO includes intra-frequency MRO and inter-frequency MRO. Inter-RAT MRO includes E-UTRAN–to–GERAN MRO and E-UTRAN–to–UTRAN MRO. Based on scopes of handover parameter optimization, intra-RAT intra-frequency MRO is cl assified into cell-level MRO and UE-level MRO. I ntra-RAT inter-frequency MRO and in ter-RAT MRO do not accommodate UE-level MRO. Cell-level MRO optimizes handover parameters for a single cell or a pair of neighboring cells to reduce abnormal handovers. Handover parameter optimization in a cell take s effect on all UEs in the cell. UE-level MRO optimizes handover parameters for UEs experiencing ping-pong handovers.

3 Intra-RAT MRO Intra-RAT MRO is a process to optimize the parameter settings related to handovers between intra- or inter-frequency LTE cells. Figure 3-1 shows the intra-RAT MRO procedure. 1. Handover scenario identification The eNodeB counts the number of each type of abnormal handover and the total number of handovers within an MRO period, which is specified by the MRO.OptPeriod parameter. 2. Handover scenario handling When the MRO period ends, the eNodeB modifies its parameter settings based on the numbers of handovers and abnormal handovers. 3. Result monitoring The eNodeB evaluates whether a ping-pong parameter adjustment occurred during MRO periods. If a ping-pong parameter adjustment occurred, the eNodeB imposes a p enalty. After modifying the parameters, the eNodeB monitors handover-related performance indicators. If handover performance improves, the eNodeB retains the parameter settings in the next MRO period. If handover performance deteriorates, the eNodeB rolls back to the previous parameter settings during the next MRO period. Figure 3-1 Intra-RAT MRO procedure

NOTE:



Parameter setting rollback in the dashed box in Figure 3-1, adjusts only the threshold for event A2 for inter-frequency MRO.

3.1 Handover Scenario Identification The eNodeB identifies premature handovers, delayed handovers, handovers to wrong cells, ping-pong handovers, and coverage-induced abnormal handovers, and counts the numbe r of each type of abnormal handovers. Figure 3-2 illustrates the areas where premature and delayed handovers occur when a UE is handed over from cell A to cell B. Figure 3-2 Premature and delayed handovers

3.1.1 Premature Handover Premature handovers are classified into the following types: Type 1 A UE receives a handover command. During the handover, the UE experiences an RLF. The radio resource control (RRC) connection is then reestablished with the source cell. This indicates a premature handover in which the signal quality of the source cell is still satisfactory for the UE or the target cell was i nappropriately selected. Type 2 A UE receives a handover command. After the handover, the UE stays in the target cell for a period shorter than the value of MRO.IntraRatHoTooEarlyTimeThd (3s by default, configurable in the target cell) and then experiences an RLF. The RRC connection for the UE is then reestablished with the source cell or another cell. If the source cell is selected, this is a premature handover in which the signal quality of the target cell is unstable. If another cell is selected, this is a premature handover in which the target cell was inappropriately selected. NOTE: For premature handovers of type 2, if the serving eNodeB, the target eNodeB, and the eNodeB serving the cell where the RRC connection is reestablished are different, RLF Indication and Handover Report messages are triggered. For details, see section 9.1.2 "Messages for global procedures" in 3GPP TS 36.423 V10.3.0.

3.1.2 Delayed Handover Delayed handovers occur in area 3 in Figure 3-2. In a delayed handover, an RLF occurs in the source cell and then the RRC connection is reestablished with another cell. When a delayed handover occurs, the UE has moved out of the source cell. Delayed handovers may occur because of coverage problems.

Delayed Inter-Frequency Handover If the eNodeB does not receive the intra-frequency measurement report, or if the eNodeB fails to deliver t he intra-frequency handover command, an RLF occurs in the source cell , and the RRC connection for the UE is then reestablished in another intra-frequency cell. In this situation, the eNodeB measures a delayed intra-frequency handover. For details ab out RLF Indication messages, see section 9.1.2.18 in 3GPP TS 36.423 V9.1.0 (2009-12).

Delayed Inter-Frequency Handover Inter-frequency handovers have the measurement-triggering (related to event A2) and handover-triggering (related to event A3-, A4-, or A5) phases. Delayed inter-frequency handovers may occur because of errors in the two phases. There are three types of delayed inter-frequency handovers: A2-related delayed inter-frequency handovers, A3- or A4-related delayed inter-frequency handovers, and A5-related delayed inter-frequency handovers. A2-related delayed inter-frequency handovers A2-related delayed inter-frequency handovers occur because the threshold for event A2 is set too low. If the eNodeB does not attempt to or fails to deliver an inter-frequency measurement configuration message to a UE in the source cell and the UE moves out of the source cell, an RLF occurs and the RRC connection is then reestablished in an inter-frequency neighboring cell. In this situation, the eNodeB measures an A2-related delayed handover. This type of A2-related delayed handovers can be further classified as A3- and A4-oriented handovers, because the RSRP threshold for A3-oriented inter-frequency event A2 is different from that for A4-oriented inter-frequency event A2. For details about the events, see Intra-RAT Mobility Management in Connected Mode Feature Parameter Description. A3- or A4-related delayed inter-frequency handovers A3- or A4-related delayed inter-frequency handovers occur because the cell individual offset (CIO) for event A3 or A4 is set too low. If the eNodeB successfully delivers an inter-frequency measurement configuration message to a UE in the source cell but does not attempt to or fails to deliver a handover command to the UE and the UE moves out of the source cell, an RLF occurs and the RRC connection is then reestablished in another cell. In this situation, the eNodeB measures an A3- or A4-related delayed inter-frequency handover. (The delivered measurement configuration determines whether the delayed inter-frequency handover is A3or A4-related.) A5-related delayed inter-frequency handovers A5-related delayed inter-frequency handovers are classified into A5-related threshold 1-based delayed inter-frequency handovers and A5-related threshold 2-based delayed inter-frequency handovers. A5-related threshold 1-based delayed inter-frequency handovers occur because the serving cell RSRP threshold for event A5 is set too low. A5-related threshold 2-based delayed inter-frequency handovers occur because the serving cell CIO for event A5 i s set too low. NOTE: If the serving eNodeB is different from the eNodeB serving the c ell where the RRC connection is reestablished, the RLF Indication exchange is triggered. For details, see section 9.1.2 "Messages for global procedures" in 3GPP TS 36.423 V10.3.0. When an eNodeB detects that a local cell receives an RRC connection reestablishment-induced RLF INDICATION message from another cell over an X2 interface and the RRC Conn Reestab Indicator IE in the RLF I NDICATION message contains the reestablishment cause value "handoverFailure", the eNodeB considers that t he UE received



the handover command in the source cell and t herefore does not consider that a delayed handover occurred.

3.1.3 Handover to a Wrong Cell Handovers to wrong cells are classified into the foll owing types: Type 1 A UE receives a handover command. After the handover, the UE stays in the target cell for a period shorter than the value of MRO.IntraRatHoTooEarlyTimeThd (3s by default, configurable in the target cell) and then experiences an RLF. The RRC connection for the UE is then reestablished with a third cell. This indicates that t he target cell was inappropriately selected because the probability that the target cell met the handover conditions was too high. Type 2 A UE receives a handover command. During the handover, the UE experiences an RLF. The RRC connection for the UE is then reestablished with a third cell. This indicates that the target cell was inappropriately selected because signal quality in the target cell was unstable and a third cell could not meet the handover conditions. NOTE: MRO against handovers to wrong cells of type 1 is the same as that against premature handovers, that is, the eNodeB decreases the probability of handovers from the source cell to the target c ell. Therefore, MRO counts handovers to wrong cells of type 1 as premature handovers. MRO against handovers to wrong cells of type 2 is the same as that against delayed handovers, that is, the eNodeB increases the probability of handovers from the source cell to a third cell. Therefore, MRO counts handovers to wrong cells of type 2 as delayed handovers. If the serving eNodeB is different from the eNodeB serving the cell where the RRC connection is reestablished, the RLF Indication exchange is triggered. For details, see section 9.1.2 "Messages for global procedures" in 3GPP TS 36.423 V10.3.0.

3.1.4 Ping-Pong Handover Ping-pong handovers increase the signaling overhead and the probability of handover failures, and they adversely affect cell throughput. Figure 3-3 Ping-pong handover decision

Ping-pong handovers occur between a specific pair of cells, such as inter-eNodeB cell A and B s hown in Figure 3-3. If the UE is handed over to a cell, the target cell evaluates ping-pong handovers, for example, at time point 1 (P1) in cell A or at time point 2 (P2) in cell B. Take cell A as a n example. At P1, cell A evaluates whether the following conditions are met: Condition 1 The UE History Information IE received by cell A indicates that the E-UTRAN cell global identifier (ECGI) of the next to last cell where the UE stayed is the same as the ECGI of cell A. Condition 2 Period 2 (the duration in which the UE stayed in the last cell, that is, cell B) is less than the value of MRO.PingpongTimeThd . Ping-pong handovers are defined differently for the following two types of MRO: Cell-level MRO If both conditions 1 and 2 are met, a ping-pong handover is counted for cell-level MRO, and the number of such ping-pong handovers during a performance counter collection period is indicated by the counter 1526728173 L.HHO.Ncell.PingPongHo. UE-level MRO If only condition 1 is met, a ping-pong handover is counted for UE-level MRO. During UE-level MRO, the eNodeB considers a UE as a ping-pong UE (that is, a UE experiencing ping-pong handovers) only when the UE experiences ping-pong handovers for multiple consecutive times. For details, see 3.2.3.2 UE-Level MRO. NOTE: When an eNodeB detects that a local cell receives an RRC connection reestablishment-induced RLF INDICATION message from another cell over an X2 interface and the RRC Conn Reestab Indicator IE in the RLF I NDICATION message contains the reestablishment cause value "reconfigurationFailure", the eNodeB does not consider that a premature handover, delayed handover, or handover to a wrong cell occurred because this IE is not associated with handover parameter settings. MRO counts the number of abnormal handovers based on the RLF INDICATION message. The RLF INDICATION message can be sent only when the NCL of the local cell includes the peer cell and the X2 links are available. If the local cell and peer cell are served by the same eNodeB, no X2 links are required. UE-level MRO is used to identify UEs experiencing ping-pong intra-frequency handovers and prevent ping-pong handovers in intra-frequency networking. TTI Bundling, ROHC, and security change will trigger intra-cell handovers and then change historical information of UEs. During identification of abnormal handovers, the eNodeB processes all consecutive cells with the same ID in the UE historical information as one cell without changing the original UE historical information.

3.1.5 Coverage-induced Abnormal Handovers 3GPP Release 9 and later define the RLF Report-based coverage check procedure. When a UE experiences a handover failure or an RLF, the UE records the measurement report a nd generates the RLF Report. If the RRC connection reestablishment, RRC access, or handover to the LTE system succeeds subsequently, the UE reports the RLF Report to the eNodeB. Based on the RLF Report, the eNodeB determines whether the source and target cells experience weak coverage. If the number of times the eNodeB determines that they experience weak coverage during an MRO period is greater than the number of abnormal handovers, abnormal handovers are caused by coverage exceptions. In this situation, the eNodeB does not optimize handover parameters. For details about the RLF Report, see 3GPP TS 36.331. As defined in 3GPP protocols, UEs complying with 3GPP Release 9 record measurement reports only when an RLF occurs and reports the RLF Report when the RRC connection is reestablished; UEs complying with 3GPP Release 10 record measurement reports when an RLF or a handover failure occurs and report the RLF Report when the RRC connection reestablishment, RRC access, or handover to the LTE system succeeds. If the cell that receives the RLF Report and the source cell experiencing coverage exceptions are ser ved by different eNodeBs, the RLF Report must be transmitted and contained in the RLF Report Contain IE of the RLF Indication message. A premature or delayed handover may occur due to coverage exceptions in the following scenarios instead of inappropriate handover parameters:



Coverage hole in the overlapping area of the two cells Coverage hole of cell A or B within their overlapping area Coverage hole or weak overlapping coverage area between cells A and B In these scenarios, a UE records and reports the RLF Report after a handover failure or an RLF occurs. Based on the recorded measurement reports of the serving and neighb oring cells, the eNodeB determines whether the abnormal handover is caused by coverage exceptions. To differentiate between coverage-induced RLFs and configuration-induced RLFs, the s ignal quality thresholds MRO. S ervi ng Rs rpTh d and MRO.NeighborRsrpThd must be set for cell s A and B, respectively. If cell A’s signal quality and cell B’s signal quality indicated in the RLF report are less than the values of MRO. S ervi ng Rs rpTh d and MRO.NeighborRsrpThd , respectively, the eNodeB determines that the RLF is coverage-induced RLF and counts coverage-induced RLFs within the MRO period. NOTE: According to 3GPP TS 36.331, the RLF Report of UEs complying with 3GPP Release 9 does not contain the ECGI information of failedPCellId and previousPCellId. The eNodeB can obtain the PCI of the source cell experiencing the handover failure or RLF only by sending t he RRC reestablishment request. If the source cell PCI conflict occ urs in the neighbor relationship of the cell that receives the RRC reestablishment request, the eNodeB preferentially identifies the source cell based on the ECGI recorded in the UE’s historical information. If the cell that receives t he RRC reestablishment request has not UE’s historical information, the RLF Indication message containing the RLF Report will not be sent. The coverage check is typically used to identify coverage-induced abnormal handovers, thereby preventing incorrect MRO adjustment. Counters related to coverage exceptions are unavailable in the current version.

3.2 Handover Scenario Handling Handover Scenario Statistics Handover scenario statistics for an MRO period are useful only if a specified number of handovers occurred within a specified time between the local cell and neighboring cell pairs recorded in the NRT. The number of handovers includes the number of outgoing handover attempts and the number of delayed handovers. The MRO.OptPeriod and MRO. S tatNumThd parameters specify the MRO period and the threshold for the number of handovers (that is, the handover statistic threshold), respectively. In the early phase of network deployment, the number of handovers within an MRO period cannot reach the handover statistics threshold in many cells; h owever, RLFs frequently occur in these cells. In this situation, the MRO procedure cannot be triggered in these cells. If users change the value of MRO.OptPeriod or MRO. S tatNumThd to increase the probability of triggering MRO in these cells, the statistics are not reliable. In this situation, MRO is performed as follows: 1. If the number of handovers between the pair of neighboring cells reaches the statistics threshold within the first MRO period, the MRO procedure is triggered in these cel ls. 2. If the number of handovers between the pair of neighboring cells does not reach the statistics threshold within the first MRO period, the eNodeB retains the number of handovers. The MRO procedure is triggered in these cells within 30 MRO periods as long as the cumulative number of handovers reaches the statistics threshold at the end of any one of the 30 periods. 3. If the cumulative number of handovers within 30 MRO periods does not reach the statistics threshold, the eNodeB resets the number to 0 and does not perform the MRO procedure in these cells.

MRO Evaluation Huawei eNodeB takes premature and delayed handovers i nto account together during MRO procedures because both premature and delayed handovers are reflected by abnormal handover events and MRO against them aims to decrease the proportion of abnormal handovers. The eNodeB identifies premature and delayed handovers and records the number o f premature handovers and the number of delayed handovers for the corresponding cell pairs in the neighboring relation table (NRT). Based on the proportion of premature or delayed handovers to all abnormal handovers (premature and delayed handovers), the eNodeB determines how to modify parameters for MRO in order to minimize the number of RLFs caus ed by premature or delayed handovers. Huawei eNodeB handles ping-pong handovers differently from premature and delayed handovers. The eNodeB first checks whether it has performed MRO against premature or dela yed handovers. If it has not, the eNodeB performs MRO against ping-pong handovers only when the MRO trigger condition is met. If the eNodeB adjusts any parameter values in an MRO pe riod, it records the adjustment. The eNodeB does not perform MRO in an MRO period during which users manually performed any of the following modifications online: Adjusting the CIO or other handover-related parameters (such as the hysteresis, threshold, offset, time-to-trigger, and filtering coefficient) Modifying the blacklist attributes of cells in neighboring cell pairs In the next MRO period, the eNodeB will perform MRO based on the manual modifications. In addition, during MRO evaluation, the eNodeB does not take into consideration how the RLF proportions fluctuate between MRO periods. For details about the CIO value range, see 3.2.4 CIO Value Range Constraints. During an MRO period, if the proportion of coverage-induced abnormal handovers is greater than the value of MRO.CoverAbnormalThd or the number of coverage-induced abnormal handovers is greater than the total number of abnormal handovers (including premature and delayed handovers), the eNodeB does not perform MRO within the current MRO period. The proportion of coverage-induced abnormal handovers is calculated using the following formula: Proportion of coverage-induced abnormal handovers = Number of coverage-induced abnormal handovers/(Number of premature handovers + Number of delayed handovers)

Optimization Modes MRO optimizes parameter settings in the mode specified by the MRO. MroOp tMode parameter. If the MRO. MroOptMode parameter is set to FREE(FREE) , the eNodeB determines parameters to be optimized based on handover scenarios and optimizes the parameter settings when the MRO period approaches its end. If the MRO. MroOptMode parameter is set to CONTROLLED(CONTROLLED) , the eNodeB reports the parameter optimization advice to the U2000 when the MRO period approaches its end. Maintenance personnel check the advice, change the suggested parameter values (optional), and then deliver the advice to the eNodeB. In controlled mode, the U2000 provides the following information: Parameter optimization advice Tracking area codes (TACs) of the affected local and neighboring cells f or users to check whether the cells are i n a certain area Values of the following internal counters Counter

Description

Total Handover numbers

Total number of outgoing handovers for a neighboring cell pair

Success Handover numbers

Number of successful handovers for a neighboring cell pair

Too early Handover numbers

Number of premature handovers for a neighboring cell pair

Too late Handover numbers

Number of delayed handovers for a neighboring cell pair



Counter

Description

A2 Related Too late Handover numbers

Number of A2-related delayed handovers for a neighboring cell pair

Pingpong Handover numbers

Number of ping-pong handovers for a neighboring cell pair

NOTE: The internal counter values on the U2000 accrue for consecutive MRO periods but not for the current MRO period. The internal counters are collected based on handover procedures and RLFs to facilitate MRO. Therefore, the values of these counters may be different from those of the external counters, which are described in the performance counter reference of eNodeBs. For example, if an RLF occurs during an intra-eNodeB handover but the RRC connection is successfully reestablished, the eNodeB regards it as a failed handover in terms of internal counter measurement but as a successful handover in terms of external counter measurement.

3.2.1 MRO Against Premature or Delayed Handovers 3.2.1.1 Intra-Frequency MRO Handover Parameter Optimization The MRO feature of Huawei eNodeBs for intra-frequency neighboring cells is controlled by the IntraFreqMroSwitch option of the ENodeBAlgoSwitch. MroS witch parameter. The eNodeB collects handover statistics regardless of whether this option is selected. NOTE: To control the MRO optimization function of a cell , set the RsvdSwPara2_bit5(ReservedSwitchParameter2_bit5) option of eNBCellRsvdPara.RsvdSwPara2 . If this option is selected and the number of handovers from the local cell to an intra-frequency neighboring cell is greater than or equal to the value of MRO. StatNumThd within an MRO period specified by MRO.OptPeriod , the eNodeB performs MRO against premature or delayed handovers between the cells when the proportion of RLF-induced abnormal handovers between the cells meets the following condition: Proportion of RLF-induced abnormal handovers > MRO.IntraRatAbnormalRatioThd NOTE: Proportion of RLF-induced abnormal handovers = (Number of premature handovers + Number of delayed handovers)/(Number of premature handovers + Number of delayed handovers + Number of successful handovers - Number of ping-pong handovers) Specifically, the eNodeB performs MRO against premature or delayed handovers as follows: If the proportion of the number of premature handovers to the total number of RLF-induced abnormal handovers is greater than MRO.IntraRatTooEarlyHoRatioThd , the eNodeB decreases the CIO for intra-frequency event A3 by one step. If the proportion of the number of delayed handovers to the total number of RLF-induced abnormal handovers is greater than the value of MRO.IntraRatTooLateHoRatioThd , the eNodeB increases the CIO for event A3 by one step for intra-frequency MRO. In this document, CIO refers to the cell-specific offset for the neighboring cell. For details about thresholds and CIOs related to handover events, see Intra-RAT Mobility Management in Connected Mode Feature Parameter Description.

Cell Reselection Parameter Optimization The intra-frequency cell reselection parameter optimization function of Huawei eNodeBs is controlled by the IntraFreqReselOptSwitch option of the ENodeBAlgoSwitch. MroS witch parameter. If this option is selected, during each MRO period specified by MRO.OptPeriod , the eNodeB evaluates whether each pair of intra-frequency cells whose CIO values need to be adjusted meet condition 1. If a pair of cells meet condition 1, the eNodeB does not optimize cell reselection parameters. If a pair of cells do not meet condition 1, the eNodeB changes the value of CellQoffset for the cells to meet both conditions 2 and 3. Condition 1: Qhyst + CellQoffset ≤ Min(Ocs + Off + Hys - Ocn) Condition 2: Qhyst + CellQoffset = Min(Ocs + Off + Hys - Ocn) Condition 3: Qhyst + CellQoffset ≥ 1 NOTE: "Min" in the preceding formulas indicates the minimum value of (Ocs + Off + Hys - Ocn) among all handover parameter groups for the current cell. Table 3-1 Mapping between variables and parameters Variable

Parameter ID

Qhyst

CellResel.Qhyst

CellQoffset

EutranIntraFreqNCell.CellQoffset

Ocs

Cell.CellSpecificOffset

Off

IntraFreqHoGroup.IntraFreqHoA3Offset

Hys

IntraFreqHoGroup.IntraFreqHoA3Hyst

Ocn

EutranIntraFreqNCell.CellIndividualOffset

For details about CellQoffset , Ocs, Off , Hys, and Ocn, see Intra-RAT Mobility Management in Connected Mode. For details about Qhyst , see Idle Mode Management .

3.2.1.2 Inter-Frequency MRO The MRO feature of Huawei eNodeBs for inter-frequency neighboring cells is jointly controlled by CellMro.InterFreqMroAdjParaSel and the InterFreqMroSwitch option under the ENodeBAlgoSwitch . MroS witch parameter to optimize abnormal inter-frequency handover scenarios. Parameters to be adjusted depend on the handover policies in use. Table 3-2 provides definitions of indicators related to different handover policies. Table 3-2 Definitions of indicators related to different handover policies



Indicator Definition

Inter-frequency A2/A3-related Handover Policy



Proportion of A2-related delayed inter-frequency handovers

Number of A3-oriented A2-related delayed interfrequency handovers/(Number of A3-oriented A2-related delayed inter-frequency handovers + Number of A3-related delayed inter-frequency handovers + Number of A3-related premature interfrequency handovers)

Number of A4-oriented A2-related delayed interfrequency handovers/(Number of A4-oriented A2-related delayed inter-frequency handovers + Number of A4-related delayed inter-frequency handovers + Number of A4-related premature interfrequency handovers)

Number of A5-oriented A2-related delayed interfrequency handovers/(Number of A5-oriented A2-related delayed inter-frequency handovers + Number of A5-related delayed inter-frequency handovers + Number of A5-related premature inter-frequency handovers)

Proportion of abnormal (Number of A3-oriented A2-related delayed interRLF-induced interfrequency handovers + Number of A3-related frequency handovers delayed inter-frequency handovers + Number of A3-related premature inter-frequency handovers)/(Number of successful handovers + Number of A3-oriented A2-related delayed interfrequency handovers + Number of A3-related delayed inter-frequency handovers + Number of A3-related premature inter-frequency handovers – Number of ping-pong handovers)

(Number of A4-oriented A2-related delayed interfrequency handovers + Number of A4-related delayed inter-frequency handovers + Number of A4-related premature inter-frequency handovers)/(Number of successful handovers + Number of A4-oriented A2-related delayed inter-frequency handovers + Number of A4-related delayed inter-frequency handovers + Number of A4-related premature interfrequency handovers – Number of p ing-pong handovers)

(Number of A5-oriented A2-related delayed interfrequency handovers + Number of A5-related delayed inter-frequency handovers + Number of A5-related premature inter-frequency handovers)/(Number of successful handovers + Number of A5-oriented A2-related delayed interfrequency handovers + Number of A5-related delayed inter-frequency handovers + Number of A5-related premature inter-frequency handovers – Number of ping-pong handovers)

Proportion of A2-unrelated premature interfrequency handovers

Number of A3-related premature i nter-frequency handovers/(Number of A3-related delayed interfrequency handovers + Number of A3-oriented A2-related delayed inter-frequency handovers + Number of A3-related premature i nter-frequency handovers)

Number of A4-related premature inter-frequency handovers/(Number of A4-related delayed interfrequency handovers + Number of A4-oriented A2-related delayed inter-frequency handovers + Number of A4-related premature inter-frequency handovers)

Number of A5-related premature inter-frequency handovers/(Number of A5-related delayed interfrequency handovers + Number of A5-oriented A2-related delayed inter-frequency handovers + Number of A5-related premature inter-frequency handovers)

Proportion of A2-unrelated delayed inter-frequency handovers

(Number of A3-related delayed inter-frequency handovers + Number of A3-oriented A2-related delayed inter-frequency handovers)/(Number of A3-related delayed inter-frequency handovers + Number of A3-oriented A2-related delayed interfrequency handovers + Number of A3-related premature inter-frequency handovers)

(Number of A4-related delayed inter-frequency handovers + Number of A4-oriented A2-related delayed inter-frequency handovers)/(Number of A4-related delayed inter-frequency handovers + Number of A4-oriented A2-related delayed interfrequency handovers + Number of A4-related premature inter-frequency handovers)

A5-related threshold 1-based delayed inter-frequency handovers Number of A5-related threshold 1-based delayed inter-frequency handovers/(Number of A5-oriented A2-related delayed inter-frequency handovers + Number of A5-related delayed interfrequency handovers + Number of A5-related premature inter-frequency handovers) A5-related threshold 2-based delayed inter-frequency handovers (Number of A5-related delayed inter-frequency handovers + Number of A5-oriented A2-related delayed inter-frequency handovers)/(Number of A5-related delayed inter-frequency handovers + Number of A5-oriented A2-related delayed interfrequency handovers + Number of A5-related premature inter-frequency handovers)

When an MRO period approaches the end: The eNodeB increases the threshold for event A2 to decrease the number of A2-related delayed handovers if all of the following conditions are met: The cumulative number of handovers reaches the threshold specified by MRO. S tatNumThd . The method for measuring the cumulative number of handovers is similar to that in intra-frequency MRO scenarios. For details, see 3.2.1.1 Intra-Frequency MRO. The proportion of A2-related delayed inter-frequency handovers is greater than the value of MRO.InterFreqMeasTooLateHoThd . The proportion of RLF-induced abnormal inter-frequency handovers is greater than t he value of MRO.IntraRatAbnormalR atioThd . The eNodeB increases threshold 1 for event A5 to decrease the number of A5-related threshold 1-based delayed handovers if all of the following conditions are met: The cumulative number of handovers reaches the threshold specified by MRO. S tatNumThd . The method for measuring the cumulative number of handovers is similar to that in intra-frequency MRO scenarios. For details, see 3.2.1.1 Intra-Frequency MRO. The proportion of A2-related delayed inter-frequency handovers is less than or equal to the value of MRO.InterFreqMeasTooLateHoThd . The proportion of A5-related threshold 1-based delayed inter-frequency handovers is greater than the value of MRO.InterFreqMeasTooLateHoThd . The proportion of RLF-induced abnormal inter-frequency handovers is greater than t he value of MRO.IntraRatAbnormalR atioThd . The eNodeB increases the CIO for A2-unrelated delayed handovers by one step if all of the following conditions are met: The cumulative number of handovers reaches the threshold specified by MRO. S tatNumThd . The method for measuring the cumulative number of handovers is similar to that in intra-frequency MRO scenarios. For details, see 3.2.1.1 Intra-Frequency MRO. The proportion of A2-related delayed inter-frequency handovers is less than or equal to the value of MRO.InterFreqMeasTooLateHoThd . The proportion of A5-related threshold 1-based delayed inter-frequency handovers is greater than the value of MRO.InterFreqMeasTooLateHoThd . The proportion of A2-unrelated delayed inter-frequency handovers is greater than or equal to the value of MRO.IntraRatTooLateHoR atioThd . The proportion of RLF-induced abnormal inter-frequency handovers is greater than t he value of MRO.IntraRatAbnormalR atioThd . The eNodeB decreases the CIO for A2-unrelated premature handovers by one step if all of t he following conditions are met: The cumulative number of handovers reaches the threshold specified by MRO. S tatNumThd . The method for measuring the cumulative number of handovers is similar to that in intra-frequency MRO scenarios. For details, see 3.2.1.1 Intra-Frequency MRO. The proportion of A2-related delayed inter-frequency handovers is less than or equal to the value of MRO.InterFreqMeasTooLateHoThd . The proportion of A5-related threshold 1-based delayed inter-frequency handovers is greater than the value of MRO.InterFreqMeasTooLateHoThd . The proportion of A2-unrelated delayed inter-frequency handovers is greater than or equal to the value of MRO.IntraRatTooEarlyHoR atioThd . The proportion of RLF-induced abnormal inter-frequency handovers is greater than t he value of MRO.IntraRatAbnormalR atioThd . NOTE: Inter-frequency MRO can be used only when handover measurement events are triggered based on the RSRP value. Inter-frequency MRO optimizes A2-unrelated abnormal handovers first and then A2-related delayed handovers during an MRO period. In the preceding parameter adjustment scenarios, the eNodeB adjusts the threshold for event A2 by one step (one step corresponds to 1 dB) each time and adjusts the CIO fo r A2-unrelated abnormal handovers according the CIO value range defined by 3GPP TS 36.331. For details, see Intra-RAT Mobility Management in Connected Mode. During the adjustment of the threshold for event A2, the adjustment value is limited by the values of InterFreqA2RsrpLowLimit , InterFreqA2Rsr pUpLimit ,



A 3InterF reqA 2R s rpL owLi mit , and A3InterFreqA2RsrpUpLimit . During MRO against A2-unrelated abnormal handovers, the CIO of the corresponding neighboring cells must be adjusted according to the CIO value range constraints. For details about the CIO value range constraints, see 3.2.4 CIO Value Range Constraints. Inter-frequency event A2 starts inter-frequency measurement, and inter-frequency event A1 stops inter-frequency measurement. The MRO algorithm will not adjust the threshold for inter-frequency event A2 to a value greater than that for inter-frequency event A1 if the threshold for inter-frequency event A1 is not adjusted. If the MRO algorithm adjusts both the threshold for inter-frequency event A2 and the threshold for inter-frequency event A1, the difference between the two thresholds is kept consta nt. During MRO against A2-related delayed inter-frequency handovers, the number of A2-related delayed inter-frequency handovers is counted based on the number of handover parameter groups because the threshold for event A2 is configured at the cell level based on handover parameter groups.

3.2.2 MRO Against Handovers to a Wrong Cell Handovers to a wrong cell are counted as premature or delayed handovers. For details about MRO against handovers to a wrong cell, see 3.2.1 MRO Against Premature or Delayed Handovers.

3.2.3 MRO Against Ping-Pong Handovers Huawei eNodeBs perform cell-level and UE-level MRO against ping-pong handovers. UE-level MRO against ping-pong handovers applies only to UEs involved in intra-frequency handovers. Cell-level MRO against ping-pong handovers and MRO against premature/delayed handovers are controlled by the IntraFreqMroSwitch and InterFreqMroSwitch options under the ENodeBAlgoSwitch. MroS witch parameter. UE-level MRO against ping-pong handovers is controlled by the UEMroSwitch option under the ENodeBAlgoSwitch . MroS witch parameter.

3.2.3.1 Cell-Level MRO If within an MRO period an eNodeB has performed MRO against premature or delayed handovers between a local cell and a neighboring cell indicated in an NRT, the eNodeB does not perform MRO against ping-pong handovers between the cells in this period. If the eNodeB has n ot performed MRO against premature or delayed handovers, the eNodeB checks conditions for performing MRO against ping-pong handovers between the cells in this period. The eNodeB performs MRO against ping-pong handovers by decreasing the CIO between the cells by one step i f all the following conditions are met: Number of outgoing handovers to the neighboring cell ≥ MRO. StatNumThd Proportion of ping-pong handovers > MRO.PingpongRatioThd where Proportion of ping-pong handovers = Number of ping-pong handovers/Total number of successful handovers Handover success rate > MRO.NcellOptThd Intra-frequency handover success rate = Number of outgoing handovers to the neighboring cel l/(Total number of outgoing handovers to an intra-frequency neighboring cell + Number of delayed handovers) Inter-frequency handover success rate = Number of outgoing handovers to the neighboring cel l/(Total number of outgoing handovers to an inter-frequency neighboring cell + Number of A2-unrelated delayed handovers + Number of A3-oriented A2-related delayed handovers + Number of A4-oriented A2-related delayed handovers) Proportion of RLF-induced abnormal handovers < MRO.IntraRatAbnormalRatioThd /2 If the preceding conditions are not met, MRO is not performed. Intra- and inter-frequency MRO against ping-pong handovers use the same mechanisms, except that i ntra-frequency MRO adjusts the CIO for intra-frequency event A3 whereas inter-frequency MRO adjusts the CIO for inter-frequency event A4 or A3.

3.2.3.2 UE-Level MRO Assume that the UE enters cell A X consecutive times according to the UE History Information IE, the MRO.UePingPongNumThd parameter is set to N and the MRO.PingpongTimeThd parameter is set to M . Then, the eNodeB delivers the CIO to the UE by adhering to the following principles: If X is less than N , the eNodeB does not consider the UE as a ping-pong UE and delivers the configured cell-specific CIO to the UE. If X is greater than or equal to N and average camping time 1 is less than M , the eNodeB considers the UE as a ping-pong UE. When X is equal to N and average stay time 1 is less than M , the eNodeB decreases the configured cell-specific CIO by one step for the UE and delivers the result to the UE. When X is greater than or equal to N + 1 and av erage camping time 2 is greater than or equal to M , the eNodeB decreases the configured cell-specific CIO by one step for the UE and delivers the result to the UE. When X is greater than or equal to N + 1 and average camping time 2 is less than M , the eNodeB decreases the configured cell-specific CIO by two steps for the UE and delivers the result to the UE. NOTE: Average camping time 1 = Total time of camping on cell B for N consecutive times/N Average camping time 2 = Total time of camping in cell B for (N + 1) consecutive times/(N + 1) The eNodeB counts the number of ping-pong handovers according to the latest UE History Information IE, despite whether the eNodeB has considered this UE as a ping-pong UE during the UE-level MRO period. For an inter-eNodeB handover, the UE History Information IE can be viewed in the HANDOVER REQUEST message sent over the S1 or X2 i nterface. The UE History Information IE cannot be viewed for an intra-eNodeB handover. After the UE-specific CIO reaches the lower limit of the CIO value range for the intra-frequency neighboring cell, UE-level MRO allows one further adjustment of the CIO. Therefore, the UE-specific CIO can be 1 dB or 2 dB smaller than the lower limit of the CIO value range for the intra-frequency neighboring cell. A large CIO value adjustment may result in a high service drop probability. This 2 dB limit reduces the probability of a service drop caused by low reference signal (RS) signal to interference plus noise ratio (SINR) in the source cell of a handover. Therefore, the UE-specific CIO value can be decreased by a maximum of 2 dB based on the cell-level CIO. The eNodeB takes special actions for UE-level MRO in the following scenarios: If a UE that has experienced a handover failure has its RRC connection reestablished to the source cell, the eNodeB considers that the handover failure was caused by an abnormal RLF. The eNodeB then does not treat this UE as a ping-pong UE or perform UE-level MRO. If a UE handed over to a cell meets the ping-pong UE requirement, the eNodeB delivers the dedicated CIO value for preventing ping-pong handovers to the UE. If the UE using this CIO experiences an RRC connection reestablishment that is not caused by handover failures and the RRC connection is successfully reestablished in this cell, the UE still uses this CIO. Otherwise, the UE uses the cell-specific CIO. When a UE-level MRO period (which is permanently 4 hours) approaches its end, the eNodeB postpones UE-level MRO by 50 seconds (fixed value) to prevent MRO conflicts if the eNodeB has adjusted parameter settings for cell-level MRO. UE-level MRO brings relatively higher gains in the following s cenario: A UE stays in the coverage areas of two cells, where signal fluctuations may result in relatively m ore ping-pong handovers, for example, a stationary UE continuously accesses services in the handover area between two cells. However, UE-level MRO may be ineffective in certain network environments. For example: A UE moves between two cells with significantly different signal levels. A UE performs ping-pong handovers among multiple cells.



A UE performs ping-pong handovers for a number of times less than the UE-level MRO criteria, for example, when a UE runs discontinuous services.

3.2.4 CIO Value Range Constraints Constraints are imposed on CIO values to ensure effective MRO. Operators can specify the CIO value ranges, to which the eNodeB reacts as follows: If operators set CellMro.CioAdjLowerLimit and CellMro.CioAdjUpperLimit to specify the CIO value range, the eNodeB implements MRO based on the parameter settings. In this case, CellMro.CioAdjLimitCfgInd must be set to cfg(configure) . If operators do not specify the CIO value range, the eNodeB automatically calculates a value range. When an MRO period approaches its end, if the CIO needs to be adjusted far away from the l ower or upper limit of the range, the eNodeB cannot change the CIO in use; if th e configured CIO is greater than or equal to the upper limit and the CIO in use needs to be decreased, the eNodeB decreases the CIO in use by one step; if the configured CIO is less t han or equal to the lower limit and the CIO in use needs to be increased, the eNodeB increases the CIO i n use by one step.

Value Range for Intra-Frequency Handovers Some parameters for intra-frequency event A3 are specific for QoS class identifiers (QCIs). The CIO value range is determined by the minimum and maximum values among the lower and upper limits calculated for all QCIs. For details about the parameters for intra-frequency event A3, see Intra-RAT Mobility Management in Connected Mode. The following describes how to determine the CIO value range: If operators expect that an intra-frequency handover is triggered when the difference of the measured signal quality between the neighboring and serving cells falls into the range of A to B, the operators should setCellMro.CioAdjLowerLimit and CellMro.CioAdjUpperLimit according to the following formulas: CioAdjLowerLimit = Min(Off + Ofs + Ocs - Ofn + Hys - B) CioAdjUpperLimit = Max(Off + Ofs + Ocs - Ofn + Hys - A) If operators do not set CellMro.CioAdjUpperLimit and CellMro.CioAdjLowerLimit , the eNodeB automatically calculates the lower and upper limits according to these formulas with A and B replaced by 2 and 5, respectively.

Value Range for Inter-Frequency Handovers The CIO value range for inter-frequency event A3 follows the same calculation mechanisms as the CIO value range for intra-frequency event A3. The entering condition for event A4 is as follows: Mn + Ofn + CIO - Hys > Thresh. Generally, a neighboring cell can provide continuous services only when Mn is higher than -110 dBm. Therefore, Huawei eNodeB calculates the upper limit of the CIO value range for event A4 as follows: Min(Thresh + 110 - Ofn + Hys). The eNodeB takes -24 as the l ower limit. In summary, the CIO value range for inter-frequency event A4 is [-24,Min(Thresh + 110 - Ofn + Hys)]. For details about the parameters for inter-frequency events A3 and A4, see Intra-RAT Mobility Management in Connected Mode.

3.3 Result Monitoring 3.3.1 Parameter Setting Rollback Parameter setting rollback adjusts only the threshold for event A2 for inter-frequency MRO and does not apply to any other parameter adjustments. To reduce the delivering of invalid inter-RAT measurements, the eNodeB rolls back the parameter setting by decreasing the threshold for event A2 when all of the following conditions are met: The cumulative number of handovers reaches the threshold specified by MRO. S tatNumThd . The method for measuring the cumulative number of handovers is similar to that in intra-frequency MRO scenarios. For details, see 3.2.1.1 Intra-Frequency MRO. The proportion of A2-related delayed inter-frequency handovers is less than the value of MRO.InterFreqA2RollBackThd . The proportion of RLF-induced abnormal inter-frequency handovers is less than half the value of MRO.IntraRatAbnormalRatioThd . The preceding three conditions are met within n consecutive MRO periods (where n is specified by MRO.InterFreqA2RollBackPeriod . If performance deteriorates, for example, the proportion of RLF-induced abnormal handovers or A2-related delayed handovers increases during an MRO period after the rollback, the eNodeB considers that the performance deterioration is caused by the rollback and therefore reverts the threshold to the pre-rollback value.

3.3.2 Penalty on Ping-Pong Parameter Adjustments Cell-Level Penalty The ping-pong modification of parameters may occur during MRO periods. Huawei eNodeB monitors the latest three parameter adjustments during MRO periods. If the last value is identical with the first value, the eNodeB assumes that a ping-pong parameter adjustment occurred. As a penalty, the eNodeB will not perform MRO throughout the next two M RO periods, each specified by MRO.OptPeriod .

UE-Level Penalty When a UE-level MRO period (4 hours) approaches its end, the eNodeB calculates the proportion of RLFs due to delayed handovers caused by UE-level MRO against ping-pong handovers as follows: Proportion of RLFs due to delayed handovers caused by UE-level MRO against ping-pong handovers = Number of such delayed handovers/(Number of times the CIO is decreased by one step + Number of times the CIO is decreased by two steps) where "Number of such delayed handovers" is the number of delayed handovers that occur after UE-level MRO against ping-pong handovers is performed in all the cells under the eNodeB within the period. "Number of times the CIO is decreased by one step" is the number of times the eNodeB decreases the CIO by one step for UE-level MRO within the period. "Number of times the CIO is decreased by two steps" is the number of times the eNodeB decreases the CIO by two steps for UE-level MRO within the period. These values are collected in the eNodeB and cannot be observed. If the proportion of RLFs due to delayed handovers caused by UE-level MRO against ping-pong handovers exceeds 5%, the eNodeB stops the UE-level ping-pong handover MRO for two periods. If the eNodeB delivered the adjusted CIOs to some UEs before imposing a UE-level penalty, the eNodeB does not change the CIOs back to their original values.

4 Inter-RAT MRO Inter-RAT MRO is a process to optimize the parameter settings related to handovers from E-UTRAN to UTRAN/GERAN. Mobility policies from E-UTRAN to UTRAN/GERAN include handovers (PS handovers and SRVCC) and redirection. As E-UTRAN is evolved from UTRAN/GERAN, UTRAN/GERAN coverage is generally continuous, which ensures successful redirection. Therefore, inter-RAT MRO mainly considers handover scenarios and optimizes parameters related to h andovers from E-UTRAN to UTRAN/GERAN. In the current version, inter-RAT MRO optimizes E-UTRAN–to–UTRAN/GERAN handover parameters. In the process of an inter-RAT handover, event A2 triggers an inter-RAT measurement and event B1 or B2 triggers the inter-RAT handover based on the measurement result. Th erefore, handover parameters involved in inter-RAT MRO include the thresholds for events A2 and B1/B2.



In the current version, i nter-RAT MRO optimizes the threshold of inter-RAT event A2 or threshold 1 of UTRAN/GERAN event B2 (INTERRATHOCOMMGROUP .UtranB2Thd1Rsrp/INTERRATHOCOMMGROUP .GeranB2Thd1Rsrp ) only when abnormal handovers are triggered by RSRP, not when abnormal handovers are triggered by RSRQ or by both RSRP and RSRQ. Inter-RAT MRO optimizes t hreshold 2 of UTRAN event B1/B2 INTERRATHOUTRANGROUP .InterRatHoUtranB1ThdRscp only when abnormal handovers are triggered by RSCP, not when abnormal handovers are triggered by EcN0 or by both RSCP and EcN0.

4.1 Handover Scenario Identification MRO identifies the following types of inter-RAT abnormal handovers: premature handovers, delayed handovers, unnecessary handovers, and ping-pong handovers. In the current version, premature or delayed handovers from E-UTRAN to UTRAN/GERAN, and unnecessary or ping-pong handovers from E-UTRAN to UTRAN can be i dentified.

4.1.1 Premature Handover A premature inter-RAT handover is defined the same as a type 1 premature intra-RAT handover. A premature inter-RAT handover typically occurs in the following scenario: The UTRAN or GERAN coverage is discontinuous. A UE initiates necessary inter-RAT handovers (based on coverage, distance, or uplink link quality) in LTE cells. After receiving the handover command, the UE fails to access the target system. Therefore, the UE returns to the source LTE cell. A premature inter-RAT handover occurs after the eNodeB sends a handov er command to the target system. Therefore, the eNodeB can track the number of premature handovers to any given system. Based on the QCIs of services, the eNodeB counts the QCI-specific number of premature handovers to each system.

4.1.2 Delayed Handover When the E-UTRAN and other systems coexist on a network, intra-RAT handovers take preference over inter-RAT handovers. When the E-UTRAN coverage is discontinuous, inter-RAT handovers are triggered for edge users. Delayed inter-RAT handovers are typically applicable when the E-UTRAN coverage is discontinuous. Delayed inter-RAT handovers are classified into A2-related delayed handovers, B1-related delayed handovers, and B2-related delayed handovers. 3GPP Release 11 defines the RLF Report-based delayed handover mechanism. The eNodeB can determine whether a UE reselects to a UTRAN cell after an RLF occurs based on the RLF Report. UEs must comply with 3GPP Release 11. As the penetration rate of such UEs i s small and will remain small for a long period of time in the future, the mechanis m defined in 3GPP Release 11 is not adopted in the current version. Instead, the eNodeB identifies delayed handovers based on information obtained before the UE context is released du e to expiration. The number of delayed inter-RAT handovers is the t otal number of A2- and B1-related delayed handovers.

A2-related Delayed Handover A2-related delayed inter-RAT handovers occur because the threshold for event A2 is set too low. That is, the UE does not report the event 2 measurement report on the LTE side or the eNodeB fails to send a measurement configuration for event B1. As a result, the UE reselects to the UTRAN or GERAN after an RLF occurs. An A2-related delayed handover occurs when all of the following conditions are met: The eNodeB does not receive a premature or delayed intra-RAT handover indication. The source cell deletes the UE context when the relevant timer expires. The source cell has not sent the inter-RAT handover request based on the necessary handover algorithm. The UE h as the i nter-RAT capability. The source cell has not sent or fails to send a measurement configuration for event B1 based on the necessary handover algorithm. The eNodeB delivers measurement configurations for coverage-based inter-RAT event A2. During an A2-related delayed handover, an RLF occurs in the source cell, and the UE performs cell selection to an inter-RAT cell and enters idle mode. In this si tuation, the source cell cannot determine the target inter-RAT cell that the UE stays in. The eNodeB increases the QCI-specific number of A2-related delayed handovers to the target RAT by 1 if the UE supports that RAT.

B1-related Delayed Handover B1-related delayed inter-RAT handovers occur because the threshold for event B1 is set too high. That is, the UE cannot trigger the inter-RAT measurement report for event B1 after receiving the measurement configuration for event B1 from the eNodeB. Alternatively, the UE reports the inter-RAT measurement report for event B1 but does not send the in ter-RAT handover request based on the necessary handover algorithm. The UE reselects to the UTRAN or GERAN after an RLF occurs. A B1-related delayed handover occurs when all of the following conditions are met: The eNodeB does not receive a premature or delayed intra-RAT handover indication. The source cell deletes the UE context when the relevant timer expires. The source cell has not sent the inter-RAT handover request based on the necessary handover algorithm. The UE h as the i nter-RAT capability. The source cell has sent a measurement configuration for event B1 based on the necessary handover algorithm. The method that the eNodeB uses to measure the number of B1-related delayed handovers varies with the following scenarios: The eNodeB does not receive the inter-RAT measurement report for event B1. In this scenario, if the eNodeB has sent the measurement configuration for event B1 for a RAT, the eNodeB increases the QCI-specific number of B1-related delayed handovers by 1 for that RAT. The eNodeB receives an inter-RAT measurement report for event B1. In this scenario, the eNodeB increases the QCI-specific number of B1-related delayed handovers by 1 for the RAT of the best cell indicated in the measurement report.

B2-related Delayed Handover B2-related delayed inter-RAT handovers are classified into B2-related threshold 1-based delayed inter-RAT handovers and B2-related threshold 2-based delayed inter-RAT handovers. B2-related threshold 1-based delayed inter-RAT handovers occur because threshold 1 for event B1 is set too low. B2-related threshold 2-based delayed inter-RAT handovers occur because threshold 2 for event B1 is set too high. After event A2 is reported, the event A2 measurement configuration based on threshold 1 of event B2 is added: If the eNodeB receives neither the measurement report for event B2 nor the event A2 measurement configuration based on threshold 1 of event B2, the eNodeB counts the number of B2-related threshold 1-based delayed handovers. If the eNodeB does not receive the measurement report for event B2 but receives the event A2 measurement configuration based on threshold 1 of event B2, or if the eNodeB receives the measurement report for event B2, the eNodeB counts the number of B2-related threshold 2-based delayed handovers.

4.1.3 Unnecessary Handover 3GPP Release 10 defines unnecessary inter-RAT handovers. Such handovers typically occur in the following scenarios: The E-UTRAN coverage is good. Inter-RAT handovers are easily triggered because of inter-RAT handover parameter settings for E-UTRAN cells or large signal fluctuation in areas around E-UTRAN cells. As a result, UEs trigger inter-RAT handovers although the E-UTRAN coverage is good enough to ensure normal service provisioning. If unnecessary inter-RAT handovers are reduced, the E-UTRAN resource usage and user experience improve. 3GPP Release 10 defines the procedure for identifying unnecessary inter-RAT handovers. When a UE initiates an inter-RAT handover in an LTE cell, the handover request mess age contains information about inter-RAT measurement configuration. After the UE is handed over to the target system, the target system sends the LTE measurement configuration to the UE



based on received information about i nter-RAT measurement configuration. An unnecessary inter-RAT handover occurs when either of t he following conditions is met: Within the measurement duration specified by MRO.UnnecInterRatHoMeasTime, the RSRP of the LTE cell measured by the UE is greater than or equal to the val ue of MRO.UnnecInterRatHoRsrpThd . Within the specified measurement duration, the UE is handed over to the LTE system. Before the handover to the LTE system, the RSRP of the LTE cell measured by the UE is greater than or equal to the value of MRO.UnnecInterRatHoRsrpThd . When an unnecessary inter-RAT handover occurs, the target system sends the HO Report message using the RIM procedure, notifying t he LTE cell of the unnecessary inter-RAT handover. Figure 4-1 shows the procedure for identifying unnecessary inter-RAT handovers. For details, see 3GPP TS 36.300 in Release 10 or later. Figure 4-1 Procedure for identifying unnecessary inter-RAT handovers

Compatibility of the UTRAN on ping-pong handover identification The HO Report function of Huawei UTRAN is used for decision-making on unnecessary inter-RAT handovers. To enable the HO Report function, run the RNC MML command SET UCORRMALGOSWITCH with the HO_REPORT_SWITCH option of the HoSwitch2 parameter selected. After the HO Report function takes effect, the periodic LTE measurement is initiated when all of the following conditions are met: The Handover required message for an E-UTRAN–to–UTRAN handover contains the UE’s historical information. The first cell (the LTE cell from which the UE is most recently handed over) in the historical information is the neighboring LTE cell of the optimal UMTS cell in the UMTS cell active set. (The LTE cell is used to determine the target cell to which the HO Report is sent and the RIM Routing Address for sending the HO Report.) The IRAT Measurement Configuration IE in the Handover required message for an E-UTRAN–to–UTRAN handover contains the frequencies to be measured and the RSRP/RSRQ threshold. To prevent UEs from triggering a large number of measurements in compressed mode after the E-UTRAN–to–UTRAN handover, the following restriction on the number of HO Report-induced periodic LTE measurements in compressed mode is added to Huawei UTRAN: The RNC checks the total number of UEs that initiate measurements in compressed mode in the current cell. If the number is greater than the value of UCELLCMUSERNUM .HoReportCmUserNumThd , the identification and measurement of unnecessary handovers are not initiated. Based on the frequencies, bandwidth, and measurement time contained in the IRAT Measurement Configuration IE of the Handover required message for an E-UTRAN–to–UTRAN handover, measurement in compressed mode is performed on the neighboring LTE cell of the optimal UMTS cell in the UMTS cell active set. Within t he measurement time specified by MRO.UnnecInterR atHoMeasTi me, if measurement reports contain the LTE cells whose RSRP/RSRQ is greater than or equal to the RSRP/RSRQ threshold contained in the IRAT measurement configuration IE within each period, the RNC determines that the handover is an unnecessary handover and sets HO Report Type to Unnecessary HO to another RAT in the HO Report. The RNC then sends the HO Report to the LTE network using the RIM procedure. For details about the RIM procedure, see section "11.3.61 RIM Application Identity coding" in 3GPP TS 48.018. NOTE: HO Report-induced periodic LTE measurements in compressed mode have the lowest priority. The procedure for starting such measurements complies wi th the existing mechanism of the UTRAN. For details, see RAN Feature Documentation > Description > Mobility > Handover > Compressed Mode. HO Report-induced LTE measurements in compressed mode affect the VS.U2LTEHO.MeasCtrl.Num counter on the Huawei UTRAN. Huawei UTRAN in the current version does not implement the frequency measurement in compressed mode in compliance with 3GPP Release 10. Instead, Huawei UTRAN reads the first three frequencies (including TDD and FDD frequencies) in the E-ARFCN field of the IRAT Measurement Configuration IE and does not measure the other frequencies. Huawei UTRAN in the current version cannot simultaneously start multiple measurements in compressed mode. If periodic LTE measurement triggered by HO Report is preempted by high-priority measurement in compressed mode triggered by event 2D within the duration specified by MRO.UnnecInterRatHoMeasTime, Huawei UTRAN does not send the HO Report.

4.1.4 Ping-Pong Handover 3GPP Release 11 defines E-UTRAN-to-UTRAN ping-pong handovers as follows: After a UE is handed over from the E-UTRAN to the UTRAN, the UE camps on the UTRAN for a short period of time (specified by MRO.PingpongTimeThd ) and then is handed over back to the E-UTRAN. The eNodeB can identify the preceding ping-pong inter-RAT handovers based on the historical information of UEs. To support ping-pong inter-RAT handovers, the UTRAN must support recording the historical information of UEs. If the LTE cell to which the UE is handed over and the source LTE cell from which the UE is handed over are served by different eNodeBs, the UTRAN sends the HO Report mes sage over the X2 li nks to the E-UTRAN, notifying the E-UTRAN of the ping-pong inter-RAT handover. Compatibility of the UTRAN on ping-pong handover identification Huawei UTRAN can record the historical information of UEs and transfer it to the E-UTRAN in the E-UTRAN–to–UTRAN handover preparation phase. The E-UTRAN identifies ping-pong handovers based on the historical information of UEs. The ping-pong handover identification function has the following requirements: The Handover Required message sent from the E-UTRAN to the UTRAN contains the historical information of UEs. Otherwise, the UTRAN does not record the historical information of UEs. The Handover Required message sent from the UTRAN to the E-UTRAN contains the historical information of UEs. To meet this requirement, the PERFENH_U2L _HO_REQ_WITH_UE_HIST_INFO_SW option of the PerfEnhanceSwitch7 parameter in the RNC MML command SET UCORRMPARA must be selected.



NOTE: In the current version, Huawei UTRAN can record the historical information of a maximum of three UEs, which does not completely comply with the specifications defined in 3GPP Release 11. The E-UTRAN uses only the historical i nformation of the first two UEs. If the hi storical information of the first two UEs records UTRAN cells, the eNodeB does not consider the handover as a ping-pong handover. In MOCN scenarios, the PLMN recorded in the UE’s historical information is the common PLMN. If an operator has deployed two networks, the RNC ID must be unique for e ach network. Otherwise, the combination of (PLMN + RNCID+ CELLID) may not be unique.

4.2 Handover Scenario Handling Handover Scenario Statistics eNodeBs measure the QCI-specific numbers of premature handovers, delayed handovers, and unnecessary handovers in each identified handover scenario for each RAT. Based on the mapping between QCIs and handover parameter groups, the eNodeBs calculate the number of abnormal handovers of each type and the proportion of abnormal handovers corresponding to each handover parameter group and determine how to adjust parameters for MRO for mobility to each RAT. In Huawei eNodeBs, MRO against premature and delayed handovers in the UTRAN is controlled by the UtranMroSwitch option under the ENodeBAlgoSwitch. MroS witch parameter. MRO against premature and delayed handovers in the GERAN is controlled by the GeranMroSwitch option under the ENodeBAlgoSwitch. MroS witch parameter. MRO against unnecessary inter-RAT handovers in the UTRAN is controlled by the UtranUnnecHoOptSwitch option under the ENodeBAlgoSwitch . MroS witch parameter.

MRO Evaluation When one of these switches is turned on, the eNodeB identifies and measures abnormal handovers to the corresponding RAT and then modifies related parameters for that RAT. When an MRO period approaches its end, the eNodeB triggers MRO only when all of the following conditions are met (note that the following number of handovers and proportions a re specific to handover parameter groups): The number of handovers (including outgoing handover attempts and delayed handovers) meets the threshold specified by MRO.InterRatStatNumThd . The mechanism for processing the number of inter-RAT MRO adjustments is similar to that for processing the number of intra-RAT MRO adjustments. For details, see the description about the procedure for processing the number of intra-RAT handovers in 3.2 Handover Scenario Handling. For MRO against premature and delayed handovers, the proportion of RLF-induced abnormal handovers is greater than or equal to the value of MRO.InterRatAbnormalHoRatioThd . Proportion of RLF-induced abnormal handovers = (Number of premature handovers + Number of delayed handovers)/(Number of premature handovers + Number of delayed handovers + Number of successful handovers) For unnecessary handovers, the proportion of RLF-induced abnormal handovers is less than half the value of MRO.InterR atAbnormalHoRatioThd . The eNodeB does not perform MRO in an MRO period during which users manually adjusted the threshold for event A2 or B1 or other handover-related parameters (such as the hysteresis, threshold, offset, time-to-trigger, and filtering coefficient) online. In the next MRO period, the eNodeB will perform MRO based on the manual modifications. NOTE: In eRAN8.1, the parameter for the threshold of the proportion of RLF-induced abnormal handovers is configurable, and the default parameter value is 10%. Compared with the fixed value 1% in earlier versions, the default parameter value 10% helps decrease the probability of triggering inter-RAT MRO, thereby reducing ineffective or incorrect inter-RAT MRO adjustments. Inter-RAT MRO can be triggered only when the number of outgoing inter-RAT handover attempts is not 0, thereby reducing incorrect inter-RAT MRO adjustments when inter-RAT MRO is enabled manually and redirection is used as the inter-RAT mobility policy.

Optimization Modes After you activate inter-RAT MRO, you may need to adjust parameters in a similar manner with that for intra-RAT MRO. For details, see section 3.2 Handover Scenario Handling. In controlled mode, the U2000 provides the following information: Parameter optimization advice Values of the following internal counters Counter

Description

Total Handover Number

Total number of outgoing handovers corresponding to a handover parameter group

Success Handover Number

Total number of successful handovers corresponding to a handover parameter group

Too early Handover numbers

Total number of premature handovers corresponding to a handover parameter group

Too late Handover numbers

Total number of delayed handovers corresponding to a handover parameter group

Inter-Rat A2 Handover Later Number

Total number of A2-related delayed handovers corresponding to a handover parameter group

Unnecessary InterRat Handover Number

Total number of unnecessary inter-RAT handovers corresponding to a handover parameter group

4.2.1 MRO Against Premature Handovers After the MRO triggering conditions are met, the eNodeB increases the QCI-specific threshold for event B1 by one step for MRO against premature handovers, if both of the following conditions are met: Proportion of A2-related delayed handovers < MRO.InterRatMeasTooLateHoThd Proportion of A2-related delayed handovers = Number of A2-related delayed handovers/(Number of premature handovers + Number of delayed handovers) Number of premature inter-RAT handovers < Threshold for the premature handover proportion Number of premature inter-RAT handovers = Number of premature handovers/(Number of premature handovers + Number of A2-related delayed handovers + Number of B1-related delayed handovers) NOTE: The threshold for the premature handover proportion has a fixed value of 70%. You cannot change the value. In earlier versions, the eNodeB determines how to adjust parameters by comparing the numbers of premature handovers and delayed handovers. In the current version, the probability of triggering inter-RAT MRO decreases, and therefore ineffective or incorrect inter-RAT MRO adjustments are reduced.

4.2.2 MRO Against A2-related Delayed Handovers



After the MRO triggering conditions are met, the eNodeB increases the QCI-specific threshold for inter-RAT event A2 by one step for MRO against A2-related delayed handovers, if both of the following conditions are met: Proportion of A2-related delayed handovers > MRO.InterRatMeasTooLateHoThd Threshold for event A2 < Threshold for event A1 NOTE: Inter-RAT event A2 starts inter-RAT measurement, and inter-RAT event A1 stops inter-RAT measurement. The MRO algorithm will not adjust the threshold for event A2 to a value greater than that for event A1. For details about the parameters for events A1 and A2, see Inter-RAT Mobility Management in Connected Mode. In eRAN8.1, the parameter for the threshold of the proportion of A2-related delayed handovers is configurable, and the default parameter value is 20%. Compared with the fixed value 5% in earlier versions, the default parameter value 20% helps decrease the probability of triggering inter-RAT MRO, thereby reducing ineffective or incorrect inter-RAT MRO adjustments.

4.2.3 MRO Against B1-related Delayed Handovers After the MRO triggering conditions are met, the eNodeB decreases the QCI-specific threshold for event B1 by one step for MRO against B1-related delayed handovers, if both of the following conditions are met: Proportion of A2-related delayed handovers < MRO.InterRatMeasTooLateHoThd Proportion of B1-related delayed handovers > Threshold for the delayed handover proportion Proportion of B1-related delayed handovers = (Number of B1-related delayed handovers + Number of A2-related delayed handovers)/(Number of premature handovers + Number of A2-related delayed handovers + Number of B1-related delayed handovers) NOTE: The threshold for delay handover proportion has a fixed value of 70%. You cannot change the value.

4.2.4 MRO Against B2-related Delayed Handovers After the MRO triggering conditions are met, the eNodeB increases the QCI-specific threshold for event B2 by one step for MRO against B2-related threshold 1-based delayed handovers, if both of the following conditions are met: Proportion of A2-related delayed handovers < Threshold for A2-related delayed handover proportion Proportion of B2-related threshold 1-based delayed handovers > Threshold for A2-related delayed handover proportion Proportion of B2-related threshold 1-based delayed handovers = Number of B2-related threshold 1-based delayed handovers/(Number of premature handovers + Number of delayed handovers) After the MRO triggering conditions are met, the eNodeB decreases the QCI-specific threshold for event B2 by one step for MRO against B2-related threshold 2-based delayed handovers, if both of the following conditions are met: Proportion of A2-related delayed handovers < Threshold for A2-related delayed handover proportion Proportion of B2-related threshold 1-based delayed handovers ≤ Threshold for A2-related delayed handover proportion Proportion of B2-related threshold 2-based delayed handovers > Threshold for the delayed handover p roportion Proportion of B2-related delayed handovers = (Number of B2-related threshold 1-based delayed handovers + Number of B2-related threshold 2-based delayed handovers + Number of A2-related delayed handovers)/(Number of premature handovers + Number of A2-related delayed handovers + Number of B2-related delayed handovers)

4.2.5 MRO Against Unnecessary Handovers After the MRO triggering conditions are met, the eNodeB decreases the threshold for event A2 by one step for MRO against unnecessary inter-RAT handovers, if both of the following conditions are met: Inter-RAT handover success rate ≥ MRO.UnnecInterR atHoOptThd Inter-RAT handover success rate = Number of successful inter-RAT handovers/Number of inter-RAT handover attempts Proportion of unnecessary inter-RAT handovers ≥ MRO.UnnecInterRatHoRatioThd Proportion of unnecessary inter-RAT handovers = Number of unnecessary inter-RAT handovers/Number of inter-RAT handover attempts

4.2.6 MRO Against Ping-Pong Handovers In the current version, MRO against ping-pong handovers is not supported, but counters related to ping-pong inter-RAT handovers are measured.

4.3 Result Monitoring The eNodeB rolls back the parameter settings if MRO against any t ype of inter-RAT abnormal handover is triggered during an MRO period and the following condition is met: Proportion of RLF-induced abnormal handovers during the current MRO period ≥ Proportion of RLF-induced abnormal handovers during the previous MRO period

5 Related Features Prerequisite Features None

Mutually Exclusive Features None

Impacted Features The MRO feature adjusts CIOs and therefore it affects the following features: LBFD-002018 Mobility Management LOFD-001019 PS inter-RAT Mobility between E-UTRAN and UTRAN LOFD-001020 PS inter-RAT Mobility between E-UTRAN and GERAN LOFD-001032 Intra-LTE Load Balancing LOFD-001044 Inter-RAT Load Sharing to UTRAN LOFD-001045 Inter-RAT load Sharing to GERAN LOFD-001036 RAN Sharing with Common Carrier



LOFD-001037 RAN Sharing with Dedicated Carrier LAOFD-002001 Static TDM eICIC LAOFD-081233 Dynamic TDM eICIC MRO is closely related to mobility management in connected mode. MRO is performed based on all the parameter values initially set for mobility management in connected mode, and the parameter adjustments by MRO affect mobility management in connected mode. The identification of premature intra-RAT handovers of type 2 is affected if inter-frequency handovers based on frequency priorities are enabled and the blind handover pol icy is used or if inter-frequency MLB is enabled and the blind handover policy is us ed. If a UE triggers a blind handover based on frequency priorities or based on inter-frequency MLB, camps on the target cell for a short period of time during which an RLF occurs, and reestablishes connections in a third-party cell or the source cell, the UE context in the source ce ll is released. In this case, the eNodeB counts the number of premature handovers. The CIO adjusted for premature handovers in the preceding scenario does not take effect for blind handovers based on frequency priorities or based on inter-frequency MLB. If RAN sharing is deployed, only the primary operator can modify handover parameters.

6 Network Impact System Capacity Intra-RAT MRO Intra-RAT MRO against premature handovers: If the CIO is adjusted to an excessively small value, handovers may not be triggered even though the signal strength in the neighboring cell is much higher than that in the source cell. In this case, signal quality of UEs in the source cell becomes worse. As a result, the throughput decreases. Intra-RAT MRO against delayed handovers: If the CIO is adjusted to an excessively large value, handovers may be triggered even though the signal strength in the neighboring cell is lower than that in the source cell. In this case, signal quality of UEs in the target cell becomes worse. As a result, the throughput decreases. If the threshold for event A2 is inc reased to an excessively large value by using inter-frequency MRO, the probability of UE initiating inter-frequency measurement in the source cell increases. As a result, the user throughput decreases. Inter-RAT MRO If inter-RAT MRO against premature handovers or unnecessary handovers is triggered, UEs are less likely to be handed over the target system. As a result, UEs camp on the LTE system for a longer period of time, and the number of UEs in LTE cells is more lik ely to increase. If inter-RAT MRO against delayed handovers is triggered, UEs are more likely to be handed over the target system. As a result, UEs camp on the LTE system for a shorter period of time, and the number of UEs in LTE cells is more likely to decrease.

Network Performance Intra-RAT MRO and inter-RAT MRO for mobility from E-UTRAN to GERAN/UTRAN improves the handover success rate and decreases the rate of service drops caused by the number of premature handovers, delayed handovers, handovers to wrong cells, unnecessary handovers, and ping-pong handovers. Intra-RAT MRO aims to control the proportions of RLF-induced abnormal handovers, ping-pong handovers, and A2-related delayed handovers (only for inter-frequency MRO) within the specified thresholds. MRO against premature or ping-pong handovers adjusts CIOs in an opposite direction to MRO against delayed handovers. Therefore, the number of delayed handovers may increase during MRO against premature or ping-pong handovers, and the number of premature or ping-pong handovers may increase during MRO against delayed handovers. When an MRO period ends, the proportions of RLF-induced abnormal handovers and ping-pong handovers are lower than the specified thresholds. Inter-RAT MRO aims to control the proportions of RLF-induced abnormal handovers and unnecessary handovers within the specified thresholds. Inter-RAT MRO against premature handovers and unnecessary handovers will decrease the number of E-UTRAN–to–UTRAN/GERAN handovers. Inter-RAT MRO against delayed handovers will increase the number of E-UTRAN–to–UTRAN/GERAN handovers.

7 Engineering Guidelines for Intra-RAT MRO 7.1 When to Use Intra-RAT MRO MRO can be enabled only if an X2 interface is available between eNodeBs. If the X2 interface is unavailable between eNodeBs, RLF indication messages cannot be transmitted over the X2 interface and the eNodeBs cannot count the number of premature or delayed handovers. In this case, the MRO algorithm cannot make a correct parameter adjustment.

7.1.1 Intra-Frequency MRO Use intra-frequency MRO according to the following principles: Abnormal handovers may occur because handover or radio frequency (RF) parameters are set inappropriately in live networks. In most cases, RF optimization is performed multiple times before a new commercial network is put into service. It is recommended that intra-frequency MRO, which optimizes handover parameter settings, be enabled after the RF optimization. After large-scale capacity expansion, eNodeBs whose capacities have been expanded affect the coverage areas of the other eNodeBs. Therefore, the expansion has an impact on the neighbor relationships and handover areas of the other eNodeBs and may introduce new handover areas. It is recommended that intra-frequency MRO be disabled and the CIOs be set to 0 for eNodeBs whose capacity will not be expanded in the network. Enable intra-frequency MRO after the capacity expansion or RF optimization. When a few eNodeBs or cells are added or RF optimization is performed for only a few cells, neighbor relationships and handover areas may be affected in a way similar to that in large-scale capacity expansion. Therefore, it is recommended that intra-frequency MRO be disabled and the CIOs be set to 0 for the eNodeBs affected by the capacity expans ion or RF optimization. Enable intra-frequency MRO after the capacity expansion or RF optimization. Intra-frequency MRO cannot be used to solve RLFs due to coverage or strong interference. When such RLFs occur, it is recommended that RF optimization be performed to enhance the coverage or mitigate the interference before intra-frequency MRO is enabled. MRO requires a stable traffic model. To facilitate evaluation of gains brought by intra-frequency MRO, it is recommended that intra-frequency MRO be enabled when the X2 interface works properly and the handover area i s stable after RF optimization. As UE-level MRO has been used against pi ng-pong handovers, it is recommended that intra-frequency MRO be used against delayed or premature handovers by setting MRO.PingpongRatioThd to a large value. To prevent intra-frequency MRO from being used against ping-pong handovers, set MRO.PingpongRatioThd to 100%. Before enabling intra-frequency MRO, observe the L.HHO.NCell.HoToolate , L.HHO.NCell.HoTooearly , and L.HHO.Ncell.PingPongHo counters to check whether the proportions of abnormal handovers are greater than the corresponding thresholds ( MRO.IntraRatAbnormalR atioThd , MRO.IntraRatTooEarlyHoR atioThd , MRO.IntraRatTooLateHoRatioThd , and MRO.PingpongRatioThd ). MRO is triggered only when the preceding proportions are greater than the corresponding thresholds. For details, see 3.2 Handover Scenario Handling. After intra-frequency MRO is enabled in the preceding scenarios, it can be disabled until a new round of RF optimization is performed. MRO gains can be calculated with a stable traffic model. NOTE: To facilitate comparison of MRO gains before and after MRO is enabled, you are advised to enable MRO when the handover area becomes stable. A stable handover area indicat es that the traffic model remains unchanged for more than three consecutive traffic periods, where: A traffic period of one day is recommended. A traffic model is represented by the number of handovers and the average number of UEs.

7.1.2 Inter-Frequency MRO Use inter-frequency MRO according to the same principles for using intra-frequency MRO. For details, see 7.1.1 Intra-Frequency MRO.



Before enabling inter-frequency MRO, observe the L.HHO.NCell.HoToolate , L.HHO.NCell.HoTooearly , L.HHO.Ncell.PingPongHo, and L.HHO.NCell.A2MeasHOTooLate counters to check whether the proportions of abnormal handovers are greater than the corresponding thresholds ( MRO.IntraRatAbnormalR atioThd , MRO.IntraRatTooEarlyHoR atioThd , MRO.IntraRatTooLateHoRatioThd , MRO.PingpongRatioThd , and MRO.InterFreqMeasTooLateHoThd ). MRO is triggered only when the preceding proportions are greater than the corresponding thresholds. For details, see 3.2 Handover Scenario Handling.

7.1.3 UE-Level MRO The UE-level MRO algorithm adjusts the CIO for a UE, decreasing its ping-pong handover probability and making it stay in a c ell with higher signal quality. This algorithm effectively prevents ping-pong handovers and improves user experience. Before enabling UE-level MRO, observe the L.HHO.NCell.PingPongHo.Consecutive counter. Check whether there are an excessive number of consecutive ping-pong handovers on the live network. UE-level MRO can be triggered only when there are an excessi ve number of consecutive ping-pong handovers on the live network.

7.2 Required Information Intra- or Inter-Frequency MRO Collect the following information for intra- or inter-frequency MRO: UE capability (whether inter-frequency handovers are supported) Networking (intra- or inter-frequency) Neighbor relationships (intra- or inter-frequency neighboring cells): Whether the information about neighboring cells is complete NOTE: To transmit signaling messages such as RLF indications and handover reports over X2 interfaces, eNodeBs require bidirectional neighbor relationships. For cells with unidirectional neighbor relationships, some abnormal handovers may not be counted. Whether there are unidirectional neighbor relationships Whether neighboring cells are blacklisted Whether No handover indicator for neighboring cells is set to PERMIT_HO_ENUM(Permit Ho) X2 interface status (whether the status is normal) Inter-frequency handover policy in inter-frequency networking (CellMro.InterFreqMroAdjParaSel is set based on the inter-frequency handover policy)

UE-Level MRO Collect information about intra-frequency networking for UE-level MRO.

7.3 Planning 7.3.1 RF Planning N/A

7.3.2 Network Planning N/A

7.3.3 Hardware Planning N/A

7.4 Deployment 7.4.1 Requirements Operating Environment iManager M2000 V200R013C00, iManager U2000 V200R014C00, or later is required.

Transmission Networking For intra-RAT MRO, the X2 links between eNodeBs work properly.

License The operator has purchased and activated the license for the feature listed in Table 7-1. For details about how to activate a license, see License Management . Table 7-1 License information for MRO Feature ID

Feature Name

Model

License Control Item

NE

Sales Unit

LOFD-002005

MRO

LT1S000MRO00


eNodeB

per cell

7.4.2 Data Preparation This section describes the data that you need to collect for setting parameters. Required data is data that you must collect for all scenarios. Scenario-specific data, ho wever, is prepared depending on usage scenarios of the feature. Collect scenario-specific data when necessary for a specific feature deployment scenario. There are three types of data sources: Network plan (negotiation not required): parameter values planned and set by the operator Network plan (negotiation required): parameter values planned by the operator and negotiated with the EPC or peer transmission equipment User-defined: parameter values set by users

Required Data The following table describes the parameters that must be set in the CellMro MO to define a CIO value range for a cell. Parameter Name

Parameter ID

Data Source

Setting Notes



Parameter Name

Parameter ID

Data Source

Setting Notes

Local cell ID

CellMro.LocalCellId

Network plan (negotiation not required)

This parameter specifies the local cell ID. It uniquely identifies a cell within an eNodeB.

CIO adjustment range configuration indicator

CellMro.CioAdjLimitCfgInd


Indicates whether to set the upper and lower limits of the CIO adjustment range for the cell.


Indicates the upper limit of the CIO adjustment range for the cell.

CIO adjustment upper limit CellMro.CioAdjUpperLimit

It is recommended that this parameter be set to CFG(Configure) .

To use MRO against premature handovers, delayed handovers, and ping-pong handovers, set the CIO adjustment value range to [-1, 2] (in dB). To use MRO against premature handovers and ping-pong handovers but not against delayed handovers, set the CIO adjustment value range to [-2, 0] (in dB). It is recommended that this parameter be set to dB1(1dB) .

CIO adjustment lower limit CellMro.CioAdjLowerLimit


Indicates the lower limit of the CIO adjustment range for the cell. It is recommended that this parameter be set to dB-2(-2dB) .

The following table describes the parameter that must be set in the MRO MO to specify the MRO optimization mode. Parameter Name

Parameter ID

Data Source

MRO Optimization Mode

MRO. MR OOptMode


Setting Notes To enable the eNodeB to automatically optimize handover and cell reselection parameter settings, set this parameter to FREE(FREE). To enable manual confirmation before the eNodeB optimizes handover and cell reselection parameter settings, set this parameter to CONTROLLED(CONTROLLED) .

Scenario-specific Data Intra-Frequency MRO The following table describes the parameter that must be set in the ENodeBAlgoSwitch MO to set intra-frequency MRO. Parameter Name

Parameter ID

Data Source

MRO algorithm switch

ENodeBAlgoSwitch . MroS witch Network plan (negotiation not required)

Setting Notes To enable i ntra-frequency MRO, select the IntraFreqMroSwitch(IntraFreqMroAlgoSwitch) option. If only the IntraFreqMroSwitch(IntraFreqMroAlgoSwitch) option is selected, the eNodeB optimizes only intra-frequency handover parameters. To enable adaptive optimization of handover and cell reselection parameters, select the IntraFreqReselOptSwitch(IntraFreqReselOptSwitch) option, in addition to the IntraFreqMroSwitch(IntraFreqMroAlgoSwitch) option. Note that the eNodeB collects handover statistics regardless of how this parameter is set.

Inter-Frequency MRO The following table describes the parameter that must be set in the ENodeBAlgoSwitch MO to set inter-frequency MRO. Parameter Name

Parameter ID

Data Source



Setting Notes To enable inter-frequency MRO, select the InterFreqMroSwitch(InterFreqMroAlgoSwitch) option of the MroSwitch parameter. Note that the eNodeB collects handover statistics regardless of how this parameter is set.

UE-Level MRO The following table describes the parameter that must be set in the ENodeBAlgoSwitch MO to set UE-level MRO. Parameter Name

Parameter ID

Data Source



Setting Notes To enable UE-level MRO against ping-pong handovers, select the UEMroSwitch(UeMroAlgoSwitch) option of this parameter. Note that the eNodeB collects handover statistics regardless of how this parameter is set.

The following table describes the parameter that must be set in the eNBCellRsvdPara MO to set inter-RAT cell-level MRO. Parameter Name

Parameter ID

Data Source

Reserved Switch Parameter 2

eNBCellRsvdPara.RsvdSwPara2 Network plan (negotiation not required)

Setting Notes None

7.4.3 Activation Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs Enter the values of the parameters listed in the following table in a summary data file, which also contains other data for the new eNodeBs to be deployed. For detailed i nstructions, see section "Creating eNodeBs in Batches" in the initial configuration guide for the eNodeB. Enter the values of the parameters listed in Table 7-2 in a summary data fi le, which also contains other data for the new eNodeBs to be deployed. The summary data file may be a scenario-specific file provided by the CME or a customized fil e, depending on the following conditions: The MOs in Table 7-2 are contained in a sc enario-specific summary data file. In this situation, set the parameters in the MOs, and then verify and save t he file. Some MOs in Table 7-2 are not contained in a scenario-specific summary data file. In this situation, customize a summary data file to include the MOs before you can set the parameters. Table 7-2 MRO-relat ed arameters



MO

Sheet in the Summary Data File

Parameter Group

Remarks

ENodeBAlgoSwitch

User-defined sheet

MroSwitch

None

(Optional) CellMro

User-defined sheet

LocalCellId, CioAdjLimitCfgInd, CioAdjUpperLimit, CioAdjLowerLimit, InterFreqA2RsrpLowLimit, InterFreqA2RsrpUpLimit, A3InterFreqA2RsrpLowLimit, A3InterFreqA2RsrpUpLimit, and InterFreqMroAdjParaSel

None

MRO configuration

User-defined sheet

OptPeriod, NcellOptThd, StatNumThd, IntraRatAbnormalRatioThd, IntraRatTooEarlyHoRatioThd, IntraRatTooLateHoRatioThd, PingpongTimeThd, PingpongRatioThd, CoverAbnormalThd, ServingRsrpThd, NeighborRsrpThd, UePingPongNumThd, MroOptMode, IntraRatTooEarlyHoRatioThd, IntraRatTooLateHoRatioThd, IntraRatAbnormalRatioThd, and InterFreqA2RollBackPeriod

None

Cell-level reserved parameters

User-defined sheet

RsvdSwPara2

None

Using the CME to Perform Batch Configuration for Existing eNodeBs Batch reconfiguration using the CME is the recommended method to activate a feature on existing eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. 1. The procedure is as follows: Customize a summary data file with the MOs and parameters listed in section "Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs". For online help, press F1 when a CME window is activ e, and select CME Management > CME Guidelines > LTE Application Management > eNodeB Related Operations > Customizing a Summary Data File for Batch eNodeB Configuration . 2. Choose CME > LTE Application > Export Data > Export Base Station Bulk Configuration Data (U2000 client mode), or choose LTE Application > Export Data > Export Base Station Bulk Configuration Data (CME client mode), to export the eNodeB data stored on the CME into the customized summary data file. 3. In the summary data file, set the parameters in the MOs according to the setting notes provided in section "Data Preparation" and close the file. 4. Choose CME > LTE Application > Import Data > Import Base Station Bulk Configuration Data (U2000 client mode), or choose LTE Application > Import Data > Import Base Station Bulk Configuration Data (CME client mode), to import the summary data file into the CME, and then start the data verification. 5. After data verification is complete, choose CME > Planned Area > Export Incremental Scripts (U2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate t he incremental scripts. For detailed operations, see CME Management > CME Guidelines > Script File Management > Exporting Incremental Scripts from a Planned Data Area in the CME online help.

Using the CME to Perform Single Configuration On the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB. The procedure is as follows: 1. In the planned data area, click Base Station in the upper left corner of the configuration window. 2. In area 1 shown in Figure 7-1, select the eNodeB to which the MOs belong. Figure 7-1 MO search and configuration window

3. On the Search tab page in area 2, enter an MO name, for example, CELL. 4. In area 3, double-click the MO i n the Object Name column. All parameters in this MO are displayed in area 4. 5. Set the parameters in area 4 or 5. 6. Choose CME > Planned Area > Export Incremental Scripts (U2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate the incremental scripts.

Using MML Commands 1. (Optional; required only when the default CIO value range does not meet the network requirement) Run the MOD CELLMRO command to set the CIO value range. 2. Run the MOD MRO command to set the parameters for MRO. 3. Run the MOD ENODEBALGOSWITCH command to turn on the associated MRO switch under the MRO algorithm switch parameter.

MML Command Examples //Activating intra-frequency MRO In the following example, the IntraFreqMroSwitch(IntraFreqMroAlgoSwitch) option is selected.



MOD CELLMRO:LOCALCELLID=0,CIOADJLIMITCFGIND=CFG,CIOADJUPPERLIMIT=dB1,CIOADJLOWERLIMIT=dB-2; MOD MRO:OPTPERIOD=1440,NCELLOPTTHD=95,STATNUMTHD=1000,PINGPONGTIMETHD=2; MOD ENODEBALGOSWITCH:MROSWITCH=IntraFreqMroSwitch-1;

7.4.4 Activation Observation 7.4.4.1 Intra-Frequency MRO You can use MML commands and signaling tracing or SON logs to observe the activation of intra-frequency MRO.

Using MML Commands a nd Signaling Tracing Perform the following steps: 1. Start Uu and X2 interface tracing on the U2000 client. The following procedure describes how to start Uu interface tracing (the method of starting X2 interface tracing is similar): a. On the U2000 client, choose Monitor > Signaling Trace > Signaling Trace Management . b. On the left side of the signaling trace window as shown in Figure 7-2, double-click Uu Interface Trace to create a Uu interface tracing task. c. In the displayed Uu Interface Trace dialog box shown in Figure 7-3, select the eNodeB to be traced, and click Next. d. In the dialog box shown in Figure 7-3, set parameters for the tracing task and click Finish. Figure 7-2 Double-clicking Uu Interface Trace

Figure 7-3 Selecting the eNodeB

Figure 7-4 Setting parameters for the tracing task



2. Run the LST MRO command, and view the value of MRO optimization period(min) in the command output. 3. Within the period specified by MRO optimization period(min) , observe the following messages: A large number of RRC_CONN_REESTAB_REQ messages (indicated in Figure 7-5) in the Uu interface tracing result for the source or target cell A large number of messages in the X2 interface tracing result for the source or target cell: RLF_INDICATION messages shown in Figure 7-6 HANDOVER_CANCEL messages shown in Figure 7-7 RLF_INDICATION and HANDOVER_REPORT messages shown in Figure 7-8 Figure 7-5 RRC_CONN_REESTAB_REQ message in the Uu interface tracing result

Figure 7-6 RLF_INDICATION message in the X2 interface tracing result for the target cell

Figure 7-7 HANDOVER_CANCEL message in the X2 interface tracing result for the target cell

Figure 7-8 RLF_INDICATION and HANDOVER_REPORT messages in the X2 interface tracing result for the source cell

4. Run the LST EUTRANINTRAFREQNCELL command, and view the value of Cell individual offset(dB) in the command output. If the value changes in two consecutive MRO periods, intra-frequency MRO has been activated succ essfully. NOTE:



If the intra-frequency MRO criteria are met within an MRO period, the CIO will be changed.

Using SON Logs To use SON logs on the U2000 client to check whether intra-frequency MRO takes effect, perform the following steps: 1. On the U2000 client, choose SON > SON Log. In the Log Category drop-down list in the Query SON Log window, click MRO Log, as shown in Figure 7-9. Figure 7-9 Selecting MRO Log

2. Under Event Name, select items such as Set MRO Switch, Modify Intra-Frequency Mobility Parameters, Modify Inter-Frequency Mobility Parameters, Modify Inter-RAT (GERAN) Mobility Parameters, and Modify Inter-RAT (UTRAN) Mobility Parameters . NOTE: where Set MRO Switch indicates logs about setting MRO switches. Modify Intra-Frequency Mobility Parameters indicates logs about modifying intra-frequency mobility parameters. Modify Inter-Frequency Mobility Parameters indicates logs about modifying inter-frequency mobility parameters. Modify Inter-RAT (GERAN) Mobility Parameters indicates logs about modifying inter-RAT (GERAN) mobility parameters. Modify Inter-RAT (UTRAN) Mobility Parameters indicates logs about modifying inter-RAT (UTRAN) mobility parameters. 3. Export the SON log. In the SON log, you can view Event Name and Event Description. You can check whether the corresponding MRO function has been activated as follows: If an MRO switch is set to ON in Event Description in the SON log, the corresponding MRO function has been activated. Set MRO Switch, Modify Intra-Frequency Mobility Parameters, Modify Inter-Frequency Mobility Parameters, Modify Inter-RAT (GERAN) Mobility Parameters, and Modify Inter-RAT (UTRAN) Mobility Parameters appearing in the log, intra-frequency, inter-frequency, and inter-RAT MRO have been activated. NOTE: Event Description in SON logs provides the measured values of internal counters after handover parameters are optimized using MRO. These values are the accumulated values over consecutive MRO periods but not the measured values i n the current MRO period. SON logs record TACs of the affected local and neighboring cells for users to check whether the cells are in a certain area.

7.4.4.2 Inter-Frequency MRO The methods for observing the activation of inter-frequency MRO and intra-frequency MRO are similar. For details, see 7.4.4.1 Intra-Frequency MRO.

7.4.4.3 UE-Level MRO For intra-eNodeB ping-pong handovers, no method is currently available for obtaining UE history information. Therefore, intra-eNodeB ping-pong handovers cannot be observed by viewing UE history information. You can use X2-or S1-based handover signaling tracing to verify UE-level MRO in similar ways. The X2-based verification procedure is as follows: 1. Start Uu and X2 interface tracing on the U2000 client. For details about how to start a tracing task, see the steps in Using MML Commands and Signaling Tracing. 2. Check whether a CIO decrease instruction is included in the downlink RRC_CONN_RECFG message in the Uu tracing result. Figure 7-10 and Figure 7-11 show the instructions to decrease the CIO by 1 d B and by 2 dB, respectively. If a CIO decrease instruction is not included in the message, ping-pong handovers did not occur or the number of ping-pong handovers did not meet the trigger condition for UE-level MRO. If a CIO decrease instruction is included in the message, go to 3. Figure 7-10 Instruction to decrease the CIO by 1 dB in the RRC_CONN_RECFG message



Figure 7-11 Instruction to decrease the CIO by 2 dB in the RRC_CONN_RECFG message

3. In the X2 interface tracing result, view the UE history information that is included in the HANDOVER_REQUEST message corresponding to the RRC_CONN_RECFG message in 2, as shown in Figure 7-12. Check whether the UE has performed ping-pong handovers between the cells indicated in the hi story information. If ping-pong handovers occurred, UE-level intra-RAT MRO has been activated successfully. Figure 7-12 UE history information in the HANDOVER_REQUEST message



When UE-level MRO is enabled, observe the value of the counter L.HHO.NCell.UeMro.Cio. If the value is not 0, UE-level parameter optimization advice against ping-pong handovers has been implemented, indicating that UE-level MRO has been activated.

7.4.5 Deactivation Using the CME to Perform Batch Configuration Batch reconfiguration using the CME is the recommended method to deactivate a feature on eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure for feature deactivation is similar to that f or feature activation described in Using the CME to Perform Batch Configuration for Existing eNodeBs. In the procedure, modify parameters according to Table 7-3. Table 7-3 MRO-related parameters MO


Parameter Group

Setting Notes

ENodeBAlgoSwitch

User-defined sheet

MroSwitch

Turn off the associated MRO switch.


User-defined sheet

RsvdSwPara2

Deselect the RsvdSwPara2_bit5(ReservedSwitchParameter2_bit5) option of the RsvdSwPara2 parameter.

Using the CME to Perform Single Configuration On the CME, set parameters according to Table 7-3. For detailed instructions, see Using the CME to Perform Single Configuration described for feature activation.

Using MML Commands 1. Run the MOD ENODEBALGOSWITCH command to turn off the associated MRO switch. 2. (Optional) To deactivate the cell MRO function under an eNodeB, run the MOD ENBCELLRSVDPARA command with the RsvdSwPara2_bit5(ReservedSwitchParameter2_bit5) option of the RsvdSwPara2 parameter deselected.

MML Command Examples //Deactivating intra-frequency MRO In the following example, the UtranMroSwitch(UtranMroSwitch) option is deselected. To turn off other MRO switches, clear the associated options of the parameter. MOD ENODEBALGOSWITCH:MROSWITCH=IntraFreqMroSwitch-0;

//Deactivating the cell MRO function under an eNodeB In the following example, the RsvdSwPara2_bit5(ReservedSwitchParameter2_bit5) option is deselected. MOD ENODEBALGOSWITCH:RsvdSwPara2=RsvdSwPara2_bit5-0;

7.5 Performance Monitoring The performance of intra-RAT MRO can be monitored by observing KPIs such as the handover success rate and service drop rate. In addition, you are advised to observe the f ollowing counters: Counter ID

Counter Name

Description

1526728173

L.HHO.Ncell.PingPongHo

Number of ping-pong handovers between a specific pairs of cells

1526728355

L.HHO.NCell.HoToolate

Number of delayed intra-RAT handovers

1526728356

L.HHO.NCell.HoTooearly

Number of premature intra-RAT handovers

1526727378

L.Traffic.User.Avg

Average number of UEs in a cell

1526729053

L.HHO.NCell.A2MeasHOTooLate

Number of A2-related delayed handovers from a cell to an interfrequency neighboring cell

1526733171

L.MeasCtrl.InterFreqA3.Coverage.Num.Total

Number of inter-frequency measurement configurations for event A3

1526733172

L.MeasCtrl.InterFreqA4A5.Coverage.Num.Total

Number of inter-frequency measurement configurations for event A4/A5 sent due to coverage

1526733169

L.HHO.NCell.PingPongHo.Consecutive

Number of consecutive ping-pong handovers between two specific cells

1526733170

L.HHO.NCell.UeMro.Cio

Number of times that the anti-ping-pong-handover parameter CIO is sent in two specific cells based on UE-level MRO

7.5.1 Intra-Frequency MRO The following indicators are used to evaluate intra-frequency MRO gains: num_ho_too_late_per_user_hour : average number of delayed intra-RAT handovers per UE per hour num_ho_too_early_per_user_hour : average number of premature intra-RAT handovers per UE per hour num_pingpong_ho_per_user_hour : average number of pi ng-pong intra-RAT handovers per UE per hour Intra-frequency MRO aims at optimizing these indicators in the following scenarios: Optimizing num_ho_too_late_per_user_hour when the proportion of RLF-induced abnormal handovers is high with delayed handovers accounting for a majority of the abnormal handovers. Optimizing both num_ho_too_early_per_user_hour and num_pingpong_ho_per_user_hour when the proportion of RLF-induced abnormal handovers is high with premature handovers accounting for a majority of the abnormal handovers. Optimizing num_pingpong_ho_per_user_hour when the proportion of RLF-induced abnormal handovers is low but the number of ping-pong handovers is higher than expected. This section describes how to calculate num_ho_too_late_per_user_hour and evaluate intra-frequency MRO gains. The methods for calculating num_ho_too_early_per_user_hour and num_pingpong_ho_per_user_hour and evaluating intra-frequency MRO gains are similar. The calculation of num_ho_too_late_per_user_hour within an evaluation period T (hours) is described as follows:



NOTE: In live networks, the traffic models in weekdays are mostly different from those at weekends. To minimize the negative impact of the difference on the accuracy of MRO per formance evaluation, it is recommended that T be set to 168, which indicates 168 hours or a week. The intra-frequency MRO evaluation method is as follows: 1. Disable intra-frequency MRO for the first evaluation period, and calculate num_ho_too_late_per_user_hour Mrooff . 2. Enable MRO for the subsequent two evaluation periods, and calculate num_ho_too_late_per_user_hour Mroon. In the first one of the two periods, MRO adjusts parameters for optimization. In the second one of the two periods, network performance gradually improves. 3. Compare the calculated num_ho_too_late_per_user_hour Mroon and num_ho_too_late_per_user_hour Mrooff values. If num_ho_too_late_per_user_hour Mroon is less than num_ho_too_late_per_user_hour Mrooff , the intra-frequency MRO brings gains to delayed handovers between intra-frequency cells. If num_ho_too_late_per_user_hour Mroon is greater than or equal to num_ho_too_late_per_user_hour Mrooff , the intra-frequency MRO does not bring gains to delayed handovers between intra-frequency cells. In the first one of the two periods, MRO adjusts parameters for optimization. In the second one of the two periods, network performance gradually improves. Intra-frequency MRO against premature or delayed handovers takes precedence over intra-frequency MRO against ping-pong handovers. When evaluating intra-frequency MRO performance, pay attention to the following items: MRO against delayed handovers adjusts CIOs in an opposite direction to MRO against premature or ping-pong handovers. Therefore, a decrease in num_ho_too_late_per_user_hour may result in a slight increase in num_ho_too_early_per_user_hour and num_pingpong_ho_per_user_hour . Similarly, a decrease in num_ho_too_early_per_user_hour and num_pingpong_ho_per_user_hour may result in a slight increase in num_ho_too_late_per_user_hour . According to 3GPP specifications, intra-frequency MRO adjusts the CIO by one step each time, which is a small value. Therefore, in the second evaluation period after intrafrequency MRO is enabled, ping-pong parameter adjustments may occur on the CIO and a penalty may be imposed. The MRO evaluation must be based on a stable traffic model, which remains almost unchanged for two consecutive evaluation periods. If the traffic volume changes significantly during MRO, parameter adjustment may be affected: One or more evaluation indicators among the number of premature, delayed, or ping-pong handovers per UE per hour may fluctuate during two consecutive evaluation periods. In live networks, traffic models change, which may have the following results: When MRO is disabled, the number of premature, delayed, or ping-pong handovers may change during consecutive evaluation periods. When MRO is enabled, the evaluation indicators may fl uctuate. However, the indicators will be optimized after the traffic volumes become stable. A small change in traffic volumes brings similar changes in evaluation indicator values to those when MRO is disabled. A large change in traffic volumes may cause ineffective parameter adjustments for consecutive MRO periods. If obvious exceptions occur during MRO gain evaluation except the preceding items, diagnose the faults, for example, by checking traffic volume changes and improper parameter settings related to intra-frequency MRO.

7.5.2 Inter-Frequency MRO The following counters are used to evaluate inter-frequency MRO gains: num_ho_too_late_per_user_hour : average number of delayed intra-RAT handovers per UE per hour num_ho_too_early_per_user_hour : average number of premature intra-RAT handovers per UE per hour num_pingpong_ho_per_user_hour : average number of pi ng-pong intra-RAT handovers per UE per hour num_interfreq_A2_relative_ho_too_late_per_user_hour : average number of A2-related delayed inter-frequency handovers per UE per hour num_interfreq_A3_coverage _ measctrl _per_user_hour : average number of inter-frequency measurement configurations for event A3 per UE per hour num_interfreq_A4/A5_coverage_measCtrl _per_user_hour : average number of inter-frequency measurement configurations for event A4/A5 sent due to coverage per UE per hour Inter-frequency MRO against A2-related delayed handovers takes precedence over inter-frequency MRO against premature handovers that are not induced by A2 events and ping- pong handovers. Therefore, after an inter-frequency MRO period, the number of A2-related delayed handovers may decrease but the number of non-A2-related premature or ping-pong handovers may increase. However, after inter-frequency MRO produces the expected result, both the number of A2-related delayed handovers and the number of non-A2-related RLFs decrease.

7.5.3 UE-Level MRO The following indicator is used to evaluate UE-level MRO gains: num_consecutive_pingpong_ho_per_user_hour : average number of consecutive ping-pong handovers between two specific cells per UE per hour

7.6 Parameter Optimization You may need to adjust the following required parameters after you activate MRO. Parameter Name

Parameter ID

Data Source

Setting Notes

Ncell optimization threshold

MRO.NcellOptThd

User-defined

If the handover success rate is less than or equal to this threshold and the ping-pong handover rate is greater than the specified threshold, the eNodeB performs cell-level MRO against ping-pong handovers. A larger value of this parameter results in a lower probability of cell-level MRO against ping-pong handovers. A smaller value of this parameter results in a higher probability of cell-level MRO against ping-pong handovers.

MRO optimization period

MRO.OptPeriod

User-defined

This parameter specifies the MRO period. If the network is newly deployed or the number of UEs is small, set this parameter to a smaller value for more frequent scenario identification and parameter adjustments.


Parameter Name


Parameter ID

Data Source

Setting Notes If handover performance is stable or the network is mature, set this parameter to a larger value to prevent needless performance fluctuations. Use this parameter with MRO. S tatNumThd . If the number of outgoing handovers is less than MRO. S tatNumThd within an MRO period specified by MRO.OptPeriod , the eNodeB accumulates the number of outgoing handovers within the next period.

MRO statistics number MRO. S tatNumThd threshold

User-defined

The eNodeB starts MRO evaluation only when the number of outgoing handovers is greater than or equal to the MRO. S tatNumThd value. If the network is newly deployed or the number of UEs is few, set this parameter to a smaller value for more frequent parameter adjustments. However, if the parameter value is too small, the statistics on handover success rate may lead to unexpected MRO results. For example, a value that should be increased is actually decreased. If handover performance is stable or the network is mature, set this parameter to a larger value to prevent needless performance fluctuations. Use this parameter with MRO.OptPeriod . The eNodeB starts MRO evaluation only when the number of outgoing handovers within consecutive MRO periods specified by MRO.OptPeriod is greater than or equal to MRO. S tatNumThd .

Abnormal coverage threshold

MRO.CoverAbnormalThd

User-defined

This parameter specifies the threshold for the percentage of coverage-induced abnormal handovers to all abnormal handovers from the serving cell to a neighboring cell. If the percentage exceeds this threshold when an MRO period approaches its end, the eNodeB does not adjust MRO-related parameters of the neighboring cell within this period.

Serving cell RSRP threshold

MRO. S ervi ng R s rpThd

User-defined

This parameter is used to identify the coverage condition of the last serving cell that a UE stayed in. After a UE experiences an RLF or handover failure and then successfully reestablishes an RRC connection or accesses the network again, the UE sends an RLF report, which includes the RSRP values of the serving and neighboring cells. If the RSRP value of the serving cell i s less than this parameter value and the RSRP value of the neighboring cell is less than the MRO.NeighborRsrpThd parameter value, this RLF or handover failure is induced b y abnormal coverage rather than inappropriate MRO configurations.

Neighbour cell RSRP threshold

MRO.NeighborRsrpThd

User-defined

This parameter is used to identify the coverage condition between the last serving and neighboring cells. After a UE that had an RLF or handover failure has its RRC connection successfully reestablished or accesses the network again, the UE sends a n RLF report to the current serving cell. If the RSRP of the last serving cell in the RLF report is less than MRO. S ervi ng R s rpThd and the RSRP of the last neighboring cell is less than MRO.NeighborRsrpThd , there is abnormal coverage between the two cells.

IntraRat HO Too Early Time Threshold

MRO.IntraRatHoTooEarlyTimeThd

User-defined

This parameter is used to determine whether an abnormal intra-RAT handover occurs because a UE is handed over to a n unstable cell. If the time during which a UE camps on a cell after an intra-RAT handover is less than or equal to the value of this parameter, the eNodeB considers that the cell is unstable. A larger value of this parameter results in a higher probability that intra-RAT MRO determines intra-RAT handovers as premature handovers and adjusts parameters to reduce the number of premature handovers. A smaller value of this parameter results in a higher probability that intra-RAT MRO determines intra-RAT handovers as delayed handovers and adjusts parameters to reduce the number of delayed handovers.

IntraRat Abnormal HO Ratio Threshold

MRO.IntraRatAbnormalRatioThd

User-defined

This parameter specifies the threshold of the proportion of abnormal intra-RAT handovers. If the proportion of abnormal handovers is higher than the threshold, MRO against abnormal intra-RAT handovers is enabled. If the proportion of the abnormal handovers is lower than or equal to the threshold, MRO against abnormal intra-RAT handovers is not enabled. Abnormal handovers include delayed handovers and premature handovers. If this parameter is set to a large value, intra-RAT MRO is difficult to be triggered, thereby decreasing the probability of incorrect adjustment. If this parameter is set to a small value, intra-RAT MRO is easy to be triggered, thereby increasing the probability of incorrect adjustment.

IntraRat Too Early HO Ratio Threshold

MRO.IntraRatTooEarlyHoRatioThd User-defined

This parameter specifies the threshold of the proportion of premature intra-RAT handovers. If the proportion of the premature intra-RAT handovers is higher than this threshold and the current cell individual offset (CIO) is greater than the CIO adjustment threshold, MRO against premature handovers is enabled. If the proportion of the premature intra-RAT handovers is lower than or equal to the threshold, MRO against premature handovers is not enabled. It is recommended that this parameter be set to 50% or l arger values. If this parameter is set to a large value, MRO against premature handovers is difficult to be triggered. If this parameter is set to a small value, MRO against premature handovers is easy to be triggered.

IntraRat Too Late HO Ratio Threshold

MRO.IntraRatTooLateHoRatioThd

User-defined

This parameter specifies the threshold of the proportion of delayed intra-RAT handovers. If the proportion of the delayed intra-RAT handovers is higher than this threshold and the current cell individual offset (CIO) is less than the CIO adjustment threshold, MRO against delayed handovers is enabled. If the proportion of the delayed intra-RAT handovers is lower than or equal to the threshold, MRO against delayed handovers is not enabled. It is recommended that this parameter be set to 50% or l arger values. If this parameter is set to a large value, MRO against delayed handovers is difficult to be triggered. If this parameter is set to a small value, MRO against delayed handovers is easy to be triggered.

7.6.1 Intra-Frequency MRO You may need to adjust the following parameters after you have activated intra-frequency MRO. Parameter Name

Parameter ID

Data Source

Setting Notes



Parameter Name

Parameter ID

Data Source

Setting Notes

Pingpong ratio threshold

MRO.PingpongRatioThd

User-defined

The eNodeB performs MRO against ping-pong handovers when the proportion of ping-pong handovers is greater than this parameter value. To increase the probability of MRO against ping-pong handovers, set this parameter to a smaller value. However, if this parameter value is too small, an unexpected MRO result may occur. To decrease the probability of MRO against ping-pong handovers, set this parameter to a larger value.

Pingpong handover threshold

MRO.PingpongTimeThd

User-defined

It is recommended that this parameter be set to 2 (unit: s). This parameter specifies the duration threshold for the eNodeB to regard a handover as a ping-pong handover. If a UE is handed back over after staying in the target cell for a period shorter than this threshold, the eNodeB determines that a ping-pong handover occurred. To enable the eNodeB to identify more ping-pong handovers, set this parameter to a larger value. However, if this parameter value is too large, the eNodeB may mistake the normal movement of UEs between neighboring cells as ping-pong handovers. To enable the eNodeB to identify fewer ping-pong handovers, set this parameter to a smaller value. This parameter takes effect immediately after being modified. In addition, the number of ping-pong handovers continues to be counted into the counter L.HHO.Ncell.PingPongHo based on the modified threshold.

CIO adjustment range CellMro.CioAdjLimitCfgInd Network plan (negotiation To define the CIO value range, set this parameter to CFG(Configure) . To use the CIO value range configuration indicator not required) calculated by the MRO algorithm, set this parameter to NOT_CFG(Not configure) . CIO adjustment upper CellMro.CioAdjUpperLimit User-defined limit

This parameter specifies the upper limit of the CIO value range. If there are still many delayed handovers after MRO, increase this parameter value. CELLMRO.CioAdjUpperLimit must be greater than CELLMRO.CioAdjLowerLimit .

CIO adjustment lower CellMro.CioAdjLowerLimit User-defined limit

This parameter specifies the lower limit of the CIO value range. If there are still many premature handovers after MRO, decrease this parameter value. CELLMRO.CioAdjUpperLimit must be greater than CELLMRO.CioAdjLowerLimit .

7.6.2 Inter-Frequency MRO You may need to adjust the following parameters after you have activated inter-frequency MRO. Parameter Name

Parameter ID

Data Source

Inter frequency measurement too late handover threshold

MRO.InterFreqMeasTooLateHoThd

Us er-d ef in ed

Inter frequency A2 rollback threshold

MRO.InterFreqA2RollBackThd

Inter Frequency A2 Rollback Period

MRO.InterFreqA2RollBackPeriod

Setting Notes I t is rec om men ded th at th is pa ra met er set to 20 (unit: %). A larger value of this parameter indicates a lower probability that the event A2 threshold adjustment is triggered by inter-frequency MRO.

Us er-d ef in ed

I t is rec om men ded th at th is pa ra met er set to 2 (unit %). To increase the rollback probability, increase this parameter value. To decrease the rollback probability, decrease this parameter value.

User-defined

It is recommended that this parameter be set to 1. To decrease the probability of lowering the threshold for event A2, increase this parameter value. To increase the probability of lowering the threshold for event A2, decrease this parameter value. This parameter and MRO.InterFreqA2RollBackThd take effect simultaneously for decreasing the threshold for event A2.

Interfreq MRO Adjust Parameters Selection

CellMro.InterFreqMroAdjParaSel

User-defined

If the network inter-frequency handover policy is based on events A2 and A4, it is recommended that the InterfreqA1RsrpSwitch check box be selected. If the network inter-frequency handover policy is based on events A2 and A3, it is recommended that the A3InterfreqA1RsrpSwitch check box be selected.

7.6.3 UE-Level MRO You may need to adjust the following parameter after you have activated UE-level MRO. Parameter Name

Parameter ID

Data Source

UE PingPong Number MRO.UePingPongNumThd User-defined Threshold

Setting Notes It is recommended that thi s parameter be set to 3. This parameter specifies the threshold for the number of ping-pong handovers. If the number of UE ping-pong handovers is greater than or equal to the parameter value, the eNodeB regards this UE as a ping-pong UE. The default value is recommended. If you need to change the parameter value, a value greater than 1 is recommended. The purpose is to differentiate UE-level MRO from cell-level MRO for stationary UEs. If this parameter is set to 1, cell- and UE-level MRO functions have the same mechanism of identifying ping-pong handovers. If there are a large number of ping-pong handovers, decrease the parameter value. If there are a few ping-pong handovers, increase the parameter value.

Pingpong handover threshold

MRO.PingpongTimeThd

User-defined

This parameter specifies the time threshold for a ping-pong handover. If the average stay time in the target cell of a UE for consecutive handover times is shorter than this threshold, the eNodeB decides that this UE is a ping-pong UE. If a UE is handed back over after staying in the target cell for a period shorter than this threshold, the eNodeB determines that a ping-pong handover occurred. To enable the eNodeB to identify more ping-pong handovers, set this parameter to a larger value. However, if this parameter value is too large, the eNodeB may mistake the normal movement of UEs between neighboring cells as ping-pong handovers. To enable the eNodeB to identify fewer ping-pong handovers, s et this parameter to a smaller value.



7.7 Troubleshooting Fault 1 Fault Description There are a large number of premature and delayed i ntra-frequency or inter-frequency handovers, but handover-related parameter values are not adjusted. Fault handling: Identify and rectify the fault by performing the following procedure, as shown in Figure 7-13. Figure 7-13 Troubleshooting procedure

1. Run the LST EUTRANINTRAFREQNCELL or LST EUTRANINTERFREQNCELL command to query neighbor relationships. If inter-eNodeB neighboring cells are found, go to 2. If intra-eNodeB neighboring cells are found, go to 3. If no neighboring cell is found, configure neighbor relationships. 2. Run the DSP X2INTERFACE command to query the status of the X2 interface. If the status is normal, go to 3. If the status is abnormal, refer to the suggestion for ALM-29204 X2 Interface Fault for instructions to handle the fault. 3. Run the LST EUTRANINTRAFREQNCELL or LST EUTRANINTERFREQNCELL command, and view the value of No handover indicator in the command output. If the value is Permit Ho, go to 4. If the value is FORBID_HO_ENUM , run the MOD EUTRANINTRAFREQNCELL or MOD EUTRANINTERFREQNCELL command to set No handover indicator to PERMIT_HO_ENUM(Permit Ho). NOTE: Before changing the value of No handover indicator , check whether No handover indicator has been set to FORBID_HO_ENUM(Forbid Ho) for a specific purpose. 4. If so, do not change the val ue. Run the LST INTRAFREQBLKCELL or LST INTERFREQBLKCELL command to check whether the intra- or inter-frequency neighboring cells are blacklisted. If the cells are not blacklisted, go to 5. If the cells are blacklisted, no further action is required. 5. The eNodeB does not perform MRO on blacklisted cells. Check whether ALM-29247 Cell PCI Conflict was reported in the local cell. If the alarm was reported, refer to the handling suggestion for this alarm.

Fault 2 Fault Description It is suspected that ping-pong handovers between intra-frequency E-UTRAN cells occurred on a UE, but no CIO decrease instruction is f ound in the downlin k RRC_CONN_RECFG message in the Uu tracing result. Fault Handling Identify and solve the problem by performing the following procedure: 1. Run the LST ENODEBALGOSWITCH command to check whether UeMroAlgoSwitch under MRO algorithm switch is turned on: If the UEMroSwitch is turned off, run the MOD ENODEBALGOSWITCH command to turn on the UEMroSwitch. The troubleshooting is finished. If the UEMroSwitch is turned on, go to 2. 2. Start a Uu tracing task to check whether the UE sent a HANDOVER_REQUEST message or an RRC connection reestablishment request during the handover: If the UE sent a HANDOVER_REQUEST message, go to 3. If the UE sent an RRC connection reestablishment request, the handover is not a ping-pong handover. No further action is required. 3. Start an X2 tracing task, view the number of cells that the UE camped on and the camping durations recorded in the UE history information in the HANDOVER_REQUEST message to check whether ping-pong handover conditions have been met. If ping-pong handover conditions have not been met, the UE is not a ping-pong UE. No further action is required. If ping-pong handover conditions have been met, contact Huawei for technical support.

8 Engineering Guidelines for Inter-RAT MRO



8.1 When to Use Inter-RAT MRO If the E-UTRAN coexists with the UTRAN or GERAN on the live network and the inter-RAT handover policy is either PS handovers or SRVCC (for services with different QCIs), and if the inter-RAT neighbor relationship is complete, enable inter-RAT MRO according to the following suggestions: Inter-RAT MRO against premature and delayed handovers It is recommended that inter-RAT UTRAN MRO be enabled when all of the following conditions are met: - The E-UTRAN coexists with the UTRAN only. - The E-UTRAN or UTRAN coverage is discontinuous. - The proportions of premature and delayed inter-RAT handovers are large. It is recommended that inter-RAT GERAN MRO be enabled when all of the following conditions are met: - The E-UTRAN coexists with the GERAN only. - The E-UTRAN or GERAN coverage is discontinuous. - The proportions of premature and delayed inter-RAT handovers are large. It is recommended that both inter-RAT UTRAN MRO and inter-RAT GERAN MRO be enabled when all of the following conditions are met: - The E-UTRAN coexists with the UTRAN and GERAN. - The E-UTRAN, UTRAN, or GERAN coverage i s discontinuous. - The trigger conditions for event A2 in the UTRAN are the same as those in the GERAN. As described in 4.1.2 Delayed Handover , if the UE does no t report the measurement report for event B1, a delayed handover occurs. In this situation, the eNodeB cannot determine to which system the UE has reselected, and therefore the measured number of delayed handovers is greater than the actual number. In other cases, i t is recommended that only inter-RAT UTRAN MRO or inter-RAT GERAN MRO be enabled. Inter-RAT MRO against unnecessary handovers It is recommended that inter-RAT UTRAN MRO against unnecessary handovers be enabled when all of the following conditions are met: The E-UTRAN coexists with the UTRAN only. The E-UTRAN coverage is continuous. The UTRAN supports identification of unnecessary handovers. The proportion of unnecessary inter-RAT handovers is large. For details about requirements on the UTRAN for identification of unnecessary handovers, see 3GPP TS 36.413 and 3GPP TS 25.413. NOTE: Inter-RAT MRO against premature handovers and inter-RAT MRO against delayed handovers are controlled by t he same inter-RAT MRO switch. Inter-RAT GERAN MRO and inter-RAT UTRAN MRO are controlled by different options under the switch. Before enabling inter-RAT MRO, observe the following counters: Counters related to E-UTRAN–to–UTRAN handovers L.IRATHO.E2U.HoTooLate L.IRATHO.E2U.A2MeasHOTooLate L.IRATHO.E2U.Unnecessary.HO L.IRATHO.E2U.HoTooEarly Counters related to E-UTRAN–to–GERAN handovers L.IRATHO.E2G.HoTooLate L.IRATHO.E2G.A2MeasHOTooLate , L.IRATHO.E2G.HoTooEarly Check whether the proportion of abnormal handovers is greater than the value of MRO.InterR atAbnormalHoRatioThd , MRO.InterRatMeasTooLateHoThd , MRO.UnnecInterR atHoOptThd , or MRO.UnnecInterRatHoRatioThd . Inter-RAT MRO is triggered only if the proportion of abnormal handovers is greater than the specified threshold. For details, see 4.2 Handover Scenario Handling.

8.2 Required Information Collect the following information for inter-RAT MRO: Networking (with UTRAN or GERAN) Whether the E-UTRAN and the target sy stem (UTRAN/GERAN) coverage is continuous Statistics on abnormal handovers in the E-UTRAN and the target system (UTRAN/GERAN) Configurations of handover policies and handover parameter groups in the E-UTRAN and the target system (UTRAN/GERAN) Whether the UTRAN supports identification of unnecessary handovers and the RIM procedure Neighbor relationships with cells of that RAT: Whether the information about neighboring cells is complete Whether No handover indicator for neighboring cells is set to Permit Ho

8.3 Planning 8.3.1 RF Planning N/A

8.3.2 Network Planning N/A

8.3.3 Hardware Planning N/A

8.4 Deployment



8.4.1 Requirements Operating Environment The OSS version must be iManager U2000 V200R015C10 or later.

Transmission Networking None

License The operator has purchased and activated the license for the feature listed in Table 7-1. For details about how to activate a license, see License Management . Table 8-1 License information for MRO Feature ID

Feature Name

Model

License Control Item

LOFD-002005

MRO

LT1S000MRO00 Mobility Robust Optimization (MRO)

NE

Sales Unit

eNodeB

per cell

8.4.2 Data Preparation This section describes the data that you need to collect for setting parameters. Required data is data that you must collect for all scenarios. Scenario-specific data, ho wever, is prepared depending on usage scenarios of the feature. Collect scenario-specific data when necessary for a specific feature deployment scenario. There are three types of data sources: Network plan (negotiation not required): parameter values planned and set by the operator Network plan (negotiation required): parameter values planned by the operator and negotiated with the EPC or peer transmission equipment User-defined: parameter values set by users

Required Data The following table describes the parameters that must be set in the CellMro MO to define a local cell identifier for a cell. Parameter Name

Parameter ID

Data Source

Setting Notes

Local cell ID

CellMro.LocalCellId


This parameter specifies the local cell ID. It uniquely identifies a cell within an eNodeB.

Scenario-specific Data The following table describes the parameter that must be set in the ENodeBAlgoSwitch MO to set inter-RAT MRO. Parameter Name

Parameter ID

Data Source

Setting Notes



To enable MRO against premature and delayed handovers from E-UTRAN to UTRAN, select the UtranMroSwitch(UtranMroSwitch) check box. To enable MRO against abnormal handovers from E-UTRAN to GERAN, select the GeranMroSwitch(GeranMroSwitch) check box. To enable MRO against unnecessary handovers from E-UTRAN to UTRAN, select the UtranUnnecHoOptSwitch(UtranUnnecHoOptSwitch) check box.

The following table describes the parameter that must be set in the eNBCellRsvdPara MO to set inter-RAT cell-level MRO. Parameter Name

Parameter ID

Data Source

Setting Notes

Reserved Switch Parameter 2

eNBCellRsvdPara.RsvdSwPara2 Network plan (negotiation not required)

None

8.4.3 Activation Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs Enter the values of the parameters listed in Table 8-2 in a summary data fi le, which also contains other data for the new eNodeBs to be deployed. For detailed instructions, see "Creating eNodeBs in Batches" in the initial configuration guide for the eNodeB, which is available in the eNodeB product documentation. Then, import the summary data file into the Configuration Management Express (CME) for batch configuration. The summary data file may be a scenario-specific file provided by the CME or a customized fil e, depending on the following conditions: The managed objects (MOs) in Table 8-2 are contained in a s cenario-specific summary data file. In this situation, set the parameters in the MOs, and then verify and save the file. Some MOs in Table 8-2 are not contained in a scenario-specific summary data file. In this situation, customize a summary data file to include the MOs before you can set the parameters. Table 8-2 MRO-related parameters MO


Parameter Group

Remarks

ENodeBAlgoSwitch

User-defined sheet

MroSwitch

None

MRO

User-defined sheet

InterRatAbnormalHoRatioThd, InterRatMeasTooLateHoThd, UnnecInterRatHoRatioThd, UnnecInterRatHoRsrpThd, Unnecessary InterRat HO RSRP Threshold, and UnnecInterRatHoMeasTime

None



MO


Parameter Group

Remarks

eNBCellRsvdPara

User-defined sheet

RsvdSwPara2

None

Using the CME to Perform Batch Configuration for Existing eNodeBs Batch reconfiguration using the CME is the recommended method to activate a feature on existing eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. 1. Customize a summary data file with the MOs and parameters listed in section "Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs." For online help, press F1 when a CME window is active, and select CME Management > CME Guidelines > LTE Application Management > eNodeB Related Operations > Customizing a Summary Data File for Batch eNodeB Configuration . 2. Choose CME > LTE Application > Export Data > Export Base Station Bulk Configuration Data (U2000 client mode), or choose LTE Application > Export Data > Export Base Station Bulk Configuration Data (CME client mode), to export the eNodeB data stored on the CME into the customized summary data file. 3. In the summary data file, set the parameters in the MOs according to the setting notes provided in section "Data Preparation" and close the file. 4. Choose CME > LTE Application > Import Data > Import Base Station Bulk Configuration Data (U2000 client mode), or choose LTE Application > Import Data > Import Base Station Bulk Configuration Data (CME client mode), to import the summary data file into the CME, and then start the data verification. 5. After data verification is complete, choose CME > Planned Area > Export Incremental Scripts (U2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate t he incremental scripts. For detailed operations, see CME Management > CME Guidelines > Script File Management > Exporting Incremental Scripts from a Planned Data Area in the CME online help.

Using the CME to Perform Single Configuration On the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB. The procedure is as follows: 1. In the planned data area, click Base Station in the upper left corner of the configuration window. 2. In area 1 shown in Figure 8-1, select the eNodeB to which the MOs belong. Figure 8-1 MO search and configuration window

3. On the Search tab page in area 2, enter an MO name, for example, CELL. 4. In area 3, double-click the MO i n the Object Name column. All the parameters in this MO are displayed in area 4. 5. Set the parameters in area 4 or 5. 6. Choose CME > Planned Area > Export Incremental Scripts (U2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate the incremental scripts.

Using MML Commands 1. Run the MOD MRO command to set MRO-related parameters. 2. Run the MOD ENODEBALGOSWITCH command to turn on the associated MRO switch under the MRO algorithm switch parameter.

MML Command Examples //Activating inter-RAT MRO In the following example, the UtranMroSwitch(UtranMroSwitch) option is selected. To turn on other MRO switches, select the associated options of the MRO algorithm switch parameter: MOD MRO:OPTPERIOD=1440; MOD ENODEBALGOSWITCH:MROSWITCH=IntraFreqMroSwitch-0&InterFreqMroSwitch-0&UtranMroSwitch-1&GeranMroSwitch-0&UEMroSwitch-0;

8.4.4 Activation Observation The methods for observing the activation of inter-RAT MRO and intra-frequency MRO are similar. You can use MML commands or SON logs for activation observation.

Using MML Commands 1. Run the LST INTERRATHOCOMMGROUP command to query the settings of common parameter groups related to inter-RAT handovers. Alternatively, run the LST INTERRATHOUTRANGROUP or LST INTERRATHOGERANGROUP command to query the settings of parameter groups related to inter-RAT handovers to UTRAN/GERAN. If the settings of parameter groups related to inter-RAT handovers change during two consecutive MRO periods, inter-RAT MRO has taken effect.

Using SON Logs The observation using SON logs for the activation of inter-RAT MRO is similar to that for intra-frequency MRO. For details, see 7.4.4.1 Intra-Frequency MRO.



8.4.5 Deactivation Using the CME to Perform Batch Configuration Batch reconfiguration using the CME is the recommended method to deactivate a feature on eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure for feature deactivation is similar to that f or feature activation described in Using the CME to Perform Batch Configuration for Existing eNodeBs. In the procedure, modify parameters according to Table 8-3. Table 8-3 MRO-related parameters MO


Parameter Group

Setting Notes

ENodeBAlgoSwitch

User-defined sheet

MroSwitch

Turn off the associated MRO switch.


User-defined sheet

RsvdSwPara2

Deselect the RsvdSwPara2_bit5(ReservedSwitchParameter2_bit5) option of the RsvdSwPara2 parameter.

Using the CME to Perform Single Configuration On the CME, set parameters according to Table 8-3. For detailed instructions, see Using the CME to Perform Single Configuration described for feature activation.

Using MML Commands 1. Run the MOD ENODEBALGOSWITCH command to turn off the associated MRO switch. 2. (Optional) To deactivate the cell MRO function under an eNodeB, run the MOD ENBCELLRSVDPARA command with the RsvdSwPara2_bit5(ReservedSwitchParameter2_bit5) option of the RsvdSwPara2 parameter deselected.

MML Command Examples //Deactivating inter-RAT MRO In the following example, the UtranMroSwitch(UtranMroSwitch) option is deselected. To turn off other MRO switches, deselect the associated options of the parameter. MOD ENODEBALGOSWITCH:MROSWITCH=UtranMroSwitch-0;

//Deactivating the MRO function of a cell under an eNodeB In the following example, the RsvdSwPara2_bit5(ReservedSwitchParameter2_bit5) option is deselected. MOD ENODEBALGOSWITCH:RsvdSwPara2=RsvdSwPara2_bit5-0;

8.5 Performance Monitoring To monitor the performance of inter-RAT MRO, observe the following counters. Counter ID

Counter Name

Description

1526726989

L.IRATHO.E2W.PrepAttOut

Number of handover attempts from E-UTRAN to UTRAN

1526726991

L.IRATHO.E2W.ExecSuccOut

Number of successful handovers from E-UTRAN to UTRAN

1526726992

L.IRATHO.E2G.PrepAttOut

Number of handover attempts from E-UTRAN to GERAN

1526726994

L.IRATHO.E2G.ExecSuccOut

Number of successful handovers from E-UTRAN to GERAN

1526737680

L.IRATHO.E2U.HoTooLate

Number of delayed EUTRAN-to-UTRAN handovers

1526737681

L.IRATHO.E2G.HoTooLate

Number of delayed EUTRAN-to-GERAN handovers

1526737682

L.IRATHO.E2U.A2MeasHOTooLate

Number of delayed A2-related EUTRAN-to-UTRAN handovers

1526737683

L.IRATHO.E2G.A2MeasHOTooLate

Number of delayed A2-related EUTRAN-to-GERAN handovers

1526737686

L.IRATHO.E2U.HoTooEarly

Number of premature EUTRAN-to-UTRAN handovers

1526737687

L.IRATHO.E2G.HoTooEarly

Number of premature EUTRAN-to-GERAN handovers

1526737684

L.IRATHO.E2U.Unnecessary.HO

Number of unnecessary EUTRAN-to-UTRAN handovers

1526737685

L.IRATHO.E2U.Pingpong.HO

Number of ping-pong EUTRAN-to-UTRAN handovers

NOTE: If the UTRAN/GERAN MRO switch is turned off or the UTRAN or GERAN does not exi st on the current network, the measured value of the L.IRATHO.E2U.A2MeasHOTooLate or L.IRATHO.E2G.A2MeasHOTooLate counter is invalid. You may not subscribe to these counters. Inter-RAT MRO is applicable only when handovers are triggered by RSRP. However, the measured values of related counters are not restricted by handover triggering modes. The following indicators are used to evaluate inter-RAT MRO gains. The calculation methods are similar to those for intra-frequency MRO. For details, see 7.5.1 Intra-Frequency MRO. num_interRAT_ho_too_late_per_user_hour : average number of delayed inter-RAT handovers per UE per hour num_interRAT__ho_too_early_per_user_hour : average number of premature inter-RAT handovers per UE per hour num_interRAT__pingpong_ho_per_user_hour : average number of ping-pong inter-RAT handovers per UE per hour num_interRAT_A2_relative_ho_too_late_per_user_hour : average number of A2-related delayed inter-RAT handovers per UE per hour num_interRAT_unnecessary_ho_too_late_per_user_hour : average number of unnecessary i nter-RAT handovers per UE per hour Similar to inter-frequency MRO, inter-frequency MRO against A2-related delayed handovers takes precedence over MRO against non-A2-related premature or ping-pong handovers. Therefore, after an inter-frequency MRO period, the number of A2-related delayed handovers may decrease but the number of non-A2-related premature or ping-pong handovers may increase. However, after inter-frequency MRO produces the expected result, both the number of A2-related delayed handovers and the number of non-A2-related RLFs decrease.

8.6 Parameter Optimization



Parameter Name

Parameter ID

Data Source

InterRat Abnormal HO Ratio Threshold

MRO.InterRatAbnormalHoRatioThd User-defined

Setting Notes This parameter specifies the threshold for triggering optimization against abnormal inter-RAT handovers. If the proportion of abnormal inter-RAT handovers is greater than or equal to this threshold, the eNodeB determines whether to adjust mobility parameters. To decrease the probability of MRO against abnormal handovers, set this parameter to a smaller value. However, invalid adjustments may occur. To increase the probability of MRO against abnormal handovers, set this parameter to a larger value.

InterRat Measurement Too Late Ratio Threshold

MRO.InterRatMeasTooLateHoThd

Unnecessary IRAT Ho Optimize Threshold

MRO.UnnecInterRatHoOptThd


This parameter specifies the threshold for enabling MRO against unnecessary inter-RAT handovers based on the inter-RAT handover success rate. If the inter-RAT handover success rate is higher than or equal to this threshold, MRO against unnecessary inter-RAT handovers is enabled. To decrease the probability of triggering MRO against unnecessary inter-RAT handovers, set this parameter to a larger value. To increase the probability of triggering MRO against unnecessary inter-RAT handovers, set this parameter to a smaller value.

Unnecessary InterRat HO Ratio Threshold

MRO.UnnecInterRatHoRatioThd

User-defined

This parameter specifies the threshold of the proportion of unnecessary inter-RAT handovers. If the proportion of unnecessary inter-RAT handovers is higher than this threshold, MRO against unnecessary inter-RAT handovers is enabled.

User-defined

The unit of the value of this parameter is %. It is recommended that this parameter be set to 20. To decrease the probability of triggering adjustment of the threshold for event A2, set this parameter to a larger value. To increase the probability of triggering adjustment of the threshold for event A2, set this parameter to a s maller value.

To decrease the probability of triggering MRO against unnecessary inter-RAT handovers, set this parameter to a larger value. To increase the probability of triggering MRO against unnecessary inter-RAT handovers, set this parameter to a smaller value. Unnecessary InterRAT Ho RSRP Threshold

MRO.UnnecInterRatHoRsrpThd

User-defined

This parameter specifies the RSRP threshold for determining an unnecessary inter-RAT handover. If a UE is successfully handed over to a UTRAN or GERAN cell and the RSRP of an E-UTRAN cell is larger than or equal to this threshold within the specified duration, the handover is an unnecessary inter-RAT handover. To decrease the probability that the eNodeB determines an unnecessary inter-RAT handover, set this parameter to a larger value. To increase that the eNodeB determines an unnecessary inter-RAT handover, set this parameter to a smaller value.

Unnecessary InterRat HO Measurement Time

MRO.UnnecInterRatHoMeasTime

User-defined

This parameter specifies the measurement time used to determine whether an inter-RAT handover is an unnecessary handover. If a UE is successfully handed over to a UTRAN or GERAN cell and the RSRP of an E-UTRAN cell is larger than or equal to the specified threshold within the duration specified by this parameter, the handover is an unnecessary inter-RAT handover. To decrease the probability that the eNodeB determines an unnecessary inter-RAT handover, set this parameter to a larger value. To increase that the eNodeB determines an unnecessary inter-RAT handover, set this parameter to a smaller value.

InterRAT MRO Statistics Number Threshold

MRO.InterRatStatNumThd

User-defined

This parameter the threshold of the number of handovers (including outgoing handover attempts and delayed handovers) required for enabling optimization of inter-RAT mobility-related parameters. Optimization of inter-RAT mobility-related parameters is started when the number of handovers from the local cell to inter-RAT neighboring cells reaches this threshold. If the network is newly deployed or the number of UEs is few, set this parameter to a smaller value for more frequent parameter adjustments. However, if the parameter value is too small, t he statistics on handover success rate may lead to unexpected MRO results. For example, a value that should be increased is actually decreased. If handover performance is stable or the network is mature, set this parameter to a larger value to prevent needless performance fluctuations. Use this parameter with MRO.OptPeriod . The eNodeB triggers inter-RAT MRO only when the number of outgoing inter-RAT inter-cell handovers within consecutive MRO periods specified by MRO.OptPeriod is greater than or equal to MRO.InterRatStatNumThd .

8.7 Troubleshooting Fault 1 Fault description: There were a large number of premature and delayed inter-RAT handovers, but the threshold for event A2 or B1 was not adjusted. Fault handling: Identify and rectify the fault by performing the following procedure: 1. Run the LST UTRANNCELL or LST GERANNCELL command to query neighbor relationships with UTRAN or GERAN cells, respectively. If neighboring UTRAN or GERAN cells are found and the neighbor relationship is complete, go to 2. If no neighboring UTRAN or GERAN cells are found or the neighbor relationship is incomplete, configure neighbor relationships. 2. Run the LST UTRANNCELL or LST GERANNCELL command to query the value of No handover indicator in the command output. If the value is Permit Ho, go to 3. If the value is Forbid Ho, check whether the prohibition is reasonable. If it is, go to 3. If it is not, run the MOD UTRANNCELL or MOD GERANNCELL command to set No handover indicator to PERMIT_HO_ENUM(Permit Ho). 3. Subscribe to and make statistics on the counters related to abnormal handovers and inter-RAT handovers. If the counters indicate the measurement result for premature and delayed handovers, calculate the number of abnormal handovers based on the counter values. Compare the calculation result with the specified threshold. Determine whether the parameters related to MRO against abnormal handovers a re configured appropriately. If they are, modify the related threshold parameters. If they are not, contact Huawei technical support.



If the counters do not indicate the measurement result for premature and delayed handovers, the fault handling is complete.

Fault 2 Fault description: After the switch for UTRAN MRO against unnecessary inter-RAT handovers was turned on, MRO was not triggered, that is, the threshold for event A2 was no t adjusted. Fault handling: Identify and rectify the fault by performing the following procedure: 1. Check whether the UTRAN supports identification of unnecessary handovers and the RIM procedure. If it does, go to 2. If it does not, the fault handling is complete. 2. Run the LST UTRANNCELL command to query the neighboring relationship. If neighboring UTRAN cells are found and the neighbor relationship is complete, go to 3. If no neighboring UTRAN cells are found or the neighbor relationship is incomplete, configure the neighbor relationship. 3. Subscribe to and make statistics on the counters related to unnecessary E-UTRAN–to–UTRAN handovers and coverage-based E-UTRAN–to–UTRAN handovers. If the counters indicate the measurement result for unnecessary handovers, calculate the number of unnecessary handovers based on the counter values. Compare the calculation result with the specified threshold. Determine whether the parameters related to MRO against unnecessary h andovers are configured appropriately. If they are, modify the related threshold parameters. If they are not, contact Huawei technical support. If the counters do not indicate the measurement result for unnecessary handovers, the fault handling is complete.

9 Parameters Table 9-1 Parameters MO

Parameter ID

eNBCellRsvdPara

RsvdSwPara2

MML Command

Feature ID

Feature Name

Description

MOD ENBCELLRSVDPARA

None

None

Meaning:

LST ENBCELLRSVDPARA

Indicates reserved 32-bit switch parameter 2 that is reserved for future requirements. Note on parameter replacement: Reserved parameters are temporarily used in patch versions and will be replaced with new parameters. For example, the ID of a new parameter can signify the parameter function. Therefore, avoid using this parameter. GUI Value Range: RsvdSwPara2_bit1(ReservedSwitchParameter2_bit1), RsvdSwPara2_bit2(ReservedSwitchParameter2_bit2), RsvdSwPara2_bit3(ReservedSwitchParameter2_bit3), RsvdSwPara2_bit4(ReservedSwitchParameter2_bit4), RsvdSwPara2_bit5(ReservedSwitchParameter2_bit5), RsvdSwPara2_bit6(ReservedSwitchParameter2_bit6), RsvdSwPara2_bit7(ReservedSwitchParameter2_bit7), RsvdSwPara2_bit8(ReservedSwitchParameter2_bit8), RsvdSwPara2_bit9(ReservedSwitchParameter2_bit9), RsvdSwPara2_bit10(ReservedSwitchParameter2_bit10), RsvdSwPara2_bit11(ReservedSwitchParameter2_bit11), RsvdSwPara2_bit12(ReservedSwitchParameter2_bit12), RsvdSwPara2_bit13(ReservedSwitchParameter2_bit13), RsvdSwPara2_bit14(ReservedSwitchParameter2_bit14), RsvdSwPara2_bit15(ReservedSwitchParameter2_bit15), RsvdSwPara2_bit16(ReservedSwitchParameter2_bit16), RsvdSwPara2_bit17(ReservedSwitchParameter2_bit17), RsvdSwPara2_bit18(ReservedSwitchParameter2_bit18), RsvdSwPara2_bit19(ReservedSwitchParameter2_bit19), RsvdSwPara2_bit20(ReservedSwitchParameter2_bit20), RsvdSwPara2_bit21(ReservedSwitchParameter2_bit21), RsvdSwPara2_bit22(ReservedSwitchParameter2_bit22), RsvdSwPara2_bit23(ReservedSwitchParameter2_bit23), RsvdSwPara2_bit24(ReservedSwitchParameter2_bit24), RsvdSwPara2_bit25(ReservedSwitchParameter2_bit25), RsvdSwPara2_bit26(ReservedSwitchParameter2_bit26), RsvdSwPara2_bit27(ReservedSwitchParameter2_bit27), RsvdSwPara2_bit28(ReservedSwitchParameter2_bit28), RsvdSwPara2_bit29(ReservedSwitchParameter2_bit29), RsvdSwPara2_bit30(ReservedSwitchParameter2_bit30), RsvdSwPara2_bit31(ReservedSwitchParameter2_bit31), RsvdSwPara2_bit32(ReservedSwitchParameter2_bit32) Unit: None Actual Value Range: RsvdSwPara2_bit1, RsvdSwPara2_bit2, RsvdSwPara2_bit3, RsvdSwPara2_bit4, RsvdSwPara2_bit5, RsvdSwPara2_bit6, RsvdSwPara2_bit7, RsvdSwPara2_bit8, RsvdSwPara2_bit9, RsvdSwPara2_bit10, RsvdSwPara2_bit11, RsvdSwPara2_bit12, RsvdSwPara2_bit13, RsvdSwPara2_bit14, RsvdSwPara2_bit15, RsvdSwPara2_bit16, RsvdSwPara2_bit17, RsvdSwPara2_bit18, RsvdSwPara2_bit19, RsvdSwPara2_bit20, RsvdSwPara2_bit21, RsvdSwPara2_bit22, RsvdSwPara2_bit23, RsvdSwPara2_bit24, RsvdSwPara2_bit25, RsvdSwPara2_bit26, RsvdSwPara2_bit27, RsvdSwPara2_bit28, RsvdSwPara2_bit29,


MO

Parameter ID


MML Command

Feature ID

Feature Name

Description RsvdSwPara2_bit30, RsvdSwPara2_bit31, RsvdSwPara2_bit32 Default Value: RsvdSwPara2_bit1:On, RsvdSwPara2_bit2:On, RsvdSwPara2_bit3:On, RsvdSwPara2_bit4:On, RsvdSwPara2_bit5:On, RsvdSwPara2_bit6:On, RsvdSwPara2_bit7:On, RsvdSwPara2_bit8:On, RsvdSwPara2_bit9:On, RsvdSwPara2_bit10:On, RsvdSwPara2_bit11:On, RsvdSwPara2_bit12:On, RsvdSwPara2_bit13:On, RsvdSwPara2_bit14:On, RsvdSwPara2_bit15:On, RsvdSwPara2_bit16:On, RsvdSwPara2_bit17:On, RsvdSwPara2_bit18:On, RsvdSwPara2_bit19:On, RsvdSwPara2_bit20:On, RsvdSwPara2_bit21:On, RsvdSwPara2_bit22:On, RsvdSwPara2_bit23:On, RsvdSwPara2_bit24:On, RsvdSwPara2_bit25:On, RsvdSwPara2_bit26:On, RsvdSwPara2_bit27:On, RsvdSwPara2_bit28:On, RsvdSwPara2_bit29:On, RsvdSwPara2_bit30:On, RsvdSwPara2_bit31:On, RsvdSwPara2_bit32:On

InterRatHoCommGroup UtranB2Thd1Rsrp

ADD INTERRATHOCOMMGROUP MOD INTERRATHOCOMMGROUP

LOFD-001019 / TDLOFD001019

PS Inter-RAT Mobility between E-UTRAN and UTRAN

LST INTERRATHOCOMMGROUP

Meaning: Indicates the RSRP threshold 1 in the serving cell of event B2 for triggering E-UTRAN-to-UTRAN handovers. When the measured RSRP in the serving cell is smaller than the value of this parameter and the RSCP or Ec/N0 threshold in the neighboring cell is larger than the value of InterRatHoUtranB1ThdRscp or InterRatHoUtranB1ThdEcn0, the UE reports the event B2. GUI Value Range: -140~-43 Unit: dBm Actual Value Range: -140~-43 Default Value: -115

InterRatHoCommGroup GeranB2Thd1Rsrp

ADD INTERRATHOCOMMGROUP MOD INTERRATHOCOMMGROUP

LOFD-001020 / TDLOFD001020

PS Inter-RAT Mobility between E-UTRAN and GERAN

LST INTERRATHOCOMMGROUP

Meaning: Indicates the RSRP threshold 1 in the serving cell of event B2 for triggering E-UTRAN-to-GERAN handovers. When the measured RSRP in the serving cell is smaller than the value of this parameter and the RSSI in the neighboring cell is larger than the value of InterRatHoGeranB1Thd, the UE reports the event B2. GUI Value Range: -140~-43 Unit: dBm Actual Value Range: -140~-43 Default Value: -115

InterRatHoUtranGroup

InterRatHoUtranB1ThdRscp

ADD LOFD-001019 / INTERRATHOUTRANGROUP TDLOFD001019 MOD INTERRATHOUTRANGROUP TDLOFD001022 LST INTERRATHOUTRANGROUP

PS Inter-RAT Mobility between E-UTRAN and UTRAN SRVCC to UTRAN

Meaning: Indicates the RSCP threshold for event B1 related to coverage-based inter-RAT handover to UTRAN. This parameter specifies the requirement for RSCP of the target UTRAN cell. When the measurement value exceeds this threshold, a measurement report will be sent. GUI Value Range: -120~-25 Unit: dBm Actual Value Range: -120~-25 Default Value: -103

MRO

IntraRatHoTooEarlyTimeThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Optimization(MRO) If the time during which a UE camps on a cell after an intra-RAT handover is less than or equal to this parameter value, the eNodeB considers that the cell is unstable. A larger value of parameter results in a higher probability that intra-RAT MRO determines intra-RAT handovers as premature handovers and adjusts parameters to reduce the number of premature handovers. This decreases the number of handovers and the probability of delayed handovers. A smaller value of this parameter results in a higher probability that intra-RAT MRO determines intra-RAT handovers as delayed handovers and adjusts parameters to reduce the number of delayed handovers. This increases the number of handovers. For details, see descriptions of "short time" in "Intra-RAT MRO use case" in 3GPP TS 36.300. GUI Value Range: 1~60 Unit: s Actual Value Range: 1~60 Default Value: 3

CellMro

InterFreqMroAdjParaSel

MOD CELLMRO LST CELLMRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the selection of inter-frequency Optimization(MRO) adjustable parameters in inter-frequency MRO. InterfreqA1RsrpSwitch: Indicates whether the RSRP threshold for triggering inter-frequency event A1 in the


MO

Parameter ID


MML Command

Feature ID

Feature Name

Description inter-frequency handover parameter group can be adjusted. The RSRP threshold can be adjusted only when this switch is on. InterfreqA2RsrpSwitch: Indicates whether the RSRP threshold for triggering interfrequency event A2 in the inter-frequency handover parameter group can be adjusted. The RSRP threshold can be adjusted only when this switch is on. A3InterfreqA1RsrpSwitch: Indicates whether the RSRP threshold for triggering A3-oriented inter-frequency event A1 in the inter-frequency handover parameter group can be adjusted. The RSRP threshold can be adjusted only when this switch is on. A3InterfreqA2RsrpSwitch: Indicates whether the RSRP threshold for triggering A3-oriented inter-frequency event A2 in the interfrequency handover parameter group can be adjusted. The RSRP threshold can be adjusted only when this switch is on. InterfreqA3CioSwitch: Indicates whether the cell individual offset (CIO) of the inter-frequency neighboring cell for inter-frequency event A3 can be adjusted. The CIO can be adjusted only when this switch is on. InterfreqA4CioSwitch: Indicates whether the CIO of the inter-frequency neighboring cell for inter-frequency event A4 can be adjusted. The CIO can be adjusted only when this switch is on. InterfreqA5Switch: Indicates whether the CIO of the inter-frequency neighboring cell for inter-frequency event A5 and related threshold 1 for triggering inter-frequency event A5 can be adjusted. The CIO and related threshold 1 can be adjusted only when this switch is on. GUI Value Range: InterfreqA1RsrpSwitch(InterfreqA1RsrpSwitch), InterfreqA2RsrpSwitch(InterfreqA2RsrpSwitch), A3InterfreqA1RsrpSwitch(A3InterfreqA1RsrpSwitch), A3InterfreqA2RsrpSwitch(A3InterfreqA2RsrpSwitch), InterfreqA3CioSwitch(InterfreqA3CioSwitch), InterfreqA4CioSwitch(InterfreqA4CioSwitch), InterfreqA5Switch(InterfreqA5Switch) Unit: None Actual Value Range: InterfreqA1RsrpSwitch, InterfreqA2RsrpSwitch, A3InterfreqA1RsrpSwitch, A3InterfreqA2RsrpSwitch, InterfreqA3CioSwitch, InterfreqA4CioSwitch, InterfreqA5Switch Default Value: InterfreqA1RsrpSwitch:Off, InterfreqA2RsrpSwitch:On, A3InterfreqA1RsrpSwitch:Off, A3InterfreqA2RsrpSwitch:On, InterfreqA3CioSwitch:On, InterfreqA4CioSwitch:On, InterfreqA5Switch:On

MRO

InterFreqA2RollBackPeriod

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the number of MRO periods for Optimization(MRO) lowering the reference signal received power (RSRP) threshold. If the conditions for lowering the RSRP threshold in inter-frequency A2-related delayed handovers are met for the consecutive number of MRO periods specified by this parameter, the RSRP threshold for triggering inter-frequency event A2 is lowered. GUI Value Range: 1~30 Unit: None Actual Value Range: 1~30 Default Value: 30

ENodeBAlgoSwitch

MroSwitch

MOD ENODEBALGOSWITCH LST ENODEBALGOSWITCH

LOFD-002005 / TDLOFD002005


Meaning: Indicates whether to enable mobility robust optimization (MRO) algorithms. IntraFreqMroSwitch: If this option is selected, the eNodeB can dynamically adjust intra-frequency handover parameters to decrease the number of abnormal intra-frequency handovers. If this option is deselected, the adjustment is not performed. InterFreqMroSwitch: If this option is selected, the eNodeB can dynamically adjust inter-frequency handover parameters to decrease the number of abnormal inter-frequency handovers. If this option is deselected, the adjustment is not performed. UtranMroSwitch: If this option i s selected, the eNodeB can dynamically adjust the parameters related to inter-RAT handovers to UTRAN to decrease the number of abnormal handovers from E-UTRAN to UTRAN. If this option is deselected, the adjustment is not performed. GeranMroSwitch: If this option is selected, the eNodeB can dynamically adjust the parameters related to inter-RAT handovers to GERAN to decrease the number of abnormal handovers from E-UTRAN to GERAN. If this option is deselected, the adjustment is not performed. UEMroSwitch: If this option is selected, the eNodeB can dynamically adjust the UE-level handover parameters to decrease the number of ping-pong handovers. If this option is deselected, the adjustment is not performed. In


MO

Parameter ID


MML Command

Feature ID

Feature Name

Description this version, the function of UE-level MRO against ping-pong handovers takes effect only in intra-frequency handover scenarios. IntraFreqReselOptSwitch: If this option is s elected, the eNodeB dynamically adjusts intra-frequency cell reselection parameters, which reduces the number of unnecessary handovers and ensures steady handover success rate. If this option is deselected, the eNodeB does not adjust intra-frequency cell reselection parameters. UtranUnnecHoOptSwitch: If this option is selected, the eNodeB dynamically adjusts parameters related to inter-RAT handovers to UTRAN. This adjustment reduces the number of unnecessary handovers from E-UTRAN to UTRAN, increases the probability that UEs camp in LTE networks, and improves user experience. If this option is deselected, the eNodeB does not perform the adjustment. For FDD LTE cells, the switch of UnnecHoOptWithoutRIM must be off, otherwise, the adjustment is not performed. GeranUnnecHoOptSwitch: If this switch is on, the eNodeB dynamically adjusts parameters about handovers from E-UTRAN to GERAN. This adjustment reduces unnecessary handovers from E-UTRAN to GERAN, increases the probability that UEs camp in LTE networks, and improves user experience. If this switch is off, the eNodeB does not perform the adjustment. In the current version, this switch applies only to LTE TDD cells. IntraRatCallbackSwtich: If this switch i s on, after handover parameters are optimized in intra- or interfrequency neighboring cells, the eNodeB monitors the ratio of abnormal handovers within an MRO period for the neighboring cells. If the ratio increases, the eNodeB rolls back the parameter settings. If this switch i s off, the eNodeB does not perform the monitoring or the parameter setting rollback. In the current version, this switch applies only to LTE TDD cells. UnnecHoOptWithoutRIM: If this option is on, the eNodeB uses Huawei proprietary non-RIM-based scheme to perform optimization and adjustment for unnecessary inter-RAT handovers. If this option is off, the eNodeB uses a standard RIM-based scheme to perform optimization and adjustment for unnecessary inter-RAT handovers. In the current version, LTE FDD cells only support the standard RIM-based scheme to perform optimization and adjustment for unnecessary E-UTRAN to UTRAN handovers. GUI Value Range: IntraFreqMroSwitch(IntraFreqMroAlgoSwitch), InterFreqMroSwitch(InterFreqMroAlgoSwitch), UtranMroSwitch(UtranMroSwitch), GeranMroSwitch(GeranMroSwitch), UEMroSwitch(UeMroAlgoSwitch), IntraFreqReselOptSwitch(IntraFreqReselOptSwitch), UtranUnnecHoOptSwitch(UtranUnnecHoOptSwitch), GeranUnnecHoOptSwitch(GeranUnnecHoOptSwitch), IntraRatCallbackSwtich(IntraRatCallbackSwtich), UnnecHoOptWithoutRIM(UnnecHoOptWithoutRIM) Unit: None Actual Value Range: IntraFreqMroSwitch, InterFreqMroSwitch, UtranMroSwitch, GeranMroSwitch, UEMroSwitch, IntraFreqReselOptSwitch, UtranUnnecHoOptSwitch, GeranUnnecHoOptSwitch, IntraRatCallbackSwtich, UnnecHoOptWithoutRIM Default Value: IntraFreqMroSwitch:Off, InterFreqMroSwitch:Off, UtranMroSwitch:Off, GeranMroSwitch:Off, UEMroSwitch:Off, IntraFreqReselOptSwitch:Off, UtranUnnecHoOptSwitch:Off, GeranUnnecHoOptSwitch:Off, IntraRatCallbackSwtich:Off, UnnecHoOptWithoutRIM:Off

MRO

UnnecInterRatHoRatioThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold for the percentage of Optimization(MRO) unnecessary inter-RAT handovers used to evaluate inter-RAT MRO against unnecessary handovers. If the percentage of unnecessary inter-RAT handovers is greater than this parameter value, this type of MRO is triggered. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 20

MRO

UnnecInterRatHoRsrpThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the reference signal received power Optimization(MRO) (RSRP) threshold used to determine whether an inter-RAT handover is an unnecessary handover. After


MO

Parameter ID


MML Command

Feature ID

Feature Name

Description an inter-RAT handover, if the RSRP value of the source E-UTRAN cell measured by the UE in the target cell is consecutively greater than or equal to this parameter value within the specified period of time, the eNodeB considers that the inter-RAT handover is an unnecessary handover. GUI Value Range: -140~-44 Unit: dBm Actual Value Range: -140~-44 Default Value: -115

MRO

UnnecInterRatHoMeasTime

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the measurement time used to Optimization(MRO) determine whether an inter-RAT handover is an unnecessary handover. After an inter-RAT handover, if the reference signal received power (RSRP) value of the source E-UTRAN cell measured by the UE in the target cell is consecutively greater than a preset threshold within the period of time specified by this parameter, the eNodeB considers that the inter-RAT handover is an unnecessary handover. GUI Value Range: 0~100 Unit: s Actual Value Range: 0~100 Default Value: 2

MRO

InterRatAbnormalHoRatioThd MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold for triggering Optimization(MRO) optimization against abnormal i nter-RAT handovers. If the ratio of abnormal i nter-RAT handovers is greater than or equal to this threshold, the eNodeB determines whether to adjust mobility parameters. If the ratio of abnormal inter-RAT handovers is less than this threshold, the eNodeB does not determine whether to adjust mobility parameters. Abnormal handovers include delayed handovers and premature handovers. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 10

MRO

InterRatMeasTooLateHoThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the percentage threshold of delayed Optimization(MRO) inter-RAT handovers caused by delayed inter-RAT measurements to the sum of abnormal inter-RAT handovers (including premature handovers and delayed handovers). If the actual percentage of delayed A2-related inter-RAT handovers is greater than this parameter value, optimization on the threshold for inter-RAT event A2 is triggered. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 20

MRO

Un ne cIn te rRa tHo Opt Thd

M OD MR O LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold for the inter-RAT Optimization(MRO) handover success rate used to evaluate MRO against unnecessary inter-RAT handovers. If the inter-RAT handover success rate is greater than or equal to this parameter value, this type of MRO is triggered. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 95

MRO

OptPeriod

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the period of measurement for MRO. Optimization(MRO) During the period, the number of handovers is measured and abnormal scenarios (including premature handover, delayed handover, and ping-pong handover) are identified. After the period elapses, the eNodeB makes a decision on parameter adjustment. GUI Value Range: 1~70000 Unit: min Actual Value Range: 1~70000 Default Value: 1440

MRO

PingpongTimeThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the time threshold for ping-pong Optimization(MRO) handover. If a UE is handed over back to the source cell after staying in the target cell for a period shorter than this threshold, the eNodeB decides that a ping-pong handover occurs based on the history information about this UE. GUI Value Range: 1~60 Unit: s Actual Value Range: 1~60 Default Value: 1


MO

Parameter ID

MRO

ServingRsrpThd


MML Command

Feature ID

Feature Name

MOD MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the reference signal received power Optimization(MRO) (RSRP) threshold for the serving cell. The threshold is used to identify abnormal coverage in a serving cell. If a UE successfully reestablishes an RRC connection or reaccess the serving cell after a radio l ink failure (RLF) or a handover failure, the UE sends the eNodeB an RLF report, which includes the RSRP values of the serving cell and neighboring cell. If the RSRP value of the serving cell is less than this parameter value and the RSRP value of the neighboring cell is less than the NeighborRsrpThd parameter value, this RLF or handover failure is induced by abnormal coverage rather than inappropriate MRO configurations.

LST MRO

Description

GUI Value Range: -140~-44 Unit: dBm Actual Value Range: -140~-44 Default Value: -116 MRO

NeighborRsrpThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the reference signal received power Optimization(MRO) (RSRP) threshold for neighboring cells. The threshold is used to identify c overage-induced abnormal handovers from the serving cell to the neighboring cell. I f a UE successfully reestablishes an RRC connection or reaccess the serving cell after a radio l ink failure (RLF) or a handover failure, the UE sends the eNodeB an RLF report, which includes the RSRP values of the serving cell and neighboring cell. If the RSRP value of the serving cell is less than the ServingRsrpThd parameter value and the RSRP value of the neighboring cell is less than this parameter value, this RLF is induced by abnormal coverage rather than inappropriate MRO configurations. GUI Value Range: -140~-44 Unit: dBm Actual Value Range: -140~-44 Default Value: -116

MRO

StatNumThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold of the number of Optimization(MRO) handovers (including outgoing handover attempts and delayed handovers) required for enabling optimization of intra-RAT mobility-related parameters. Optimization of intra-RAT mobility-related parameters is started when the number of handovers from the local cell to an intra-RAT neighboring cell reaches this threshold. GUI Value Range: 0~10000 Unit: None Actual Value Range: 0~10000 Default Value: 1000

MRO

CoverAbnormalThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold for the percentage of Optimization(MRO) coverage-induced abnormal handovers to all abnormal handovers from the serving cell to a neighboring cell. I f the percentage is greater than or equal to this threshold when a mobility robustness optimization (MRO) period approaches its end, the eNodeB does not adjust MRO-related parameters of the neighboring cell within this period. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 60

MRO

MroOptMode

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the mode in which MRO takes effect. Optimization(MRO) If this parameter is set to FREE, the eNodeB automatically optimizes handover and reselection parameters. If this parameter is set to CONTROLLED, the eNodeB only reports the handover or reselection parameters to be optimized to the U2000, and the U2000 delivers the optimization on handover or cell reselection parameters after users confirm the optimization. GUI Value Range: FREE(FREE), CONTROLLED(CONTROLLED) Unit: None Actual Value Range: FREE, CONTROLLED Default Value: FREE(FREE)

MRO

IntraRatAbnormalRatioThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold of the proportion of Optimization(MRO) abnormal intra-RAT handovers. If the proportion of abnormal handovers is higher than the threshold, MRO against abnormal intra-RAT handovers is enabled. If the proportion of the abnormal handovers is lower than or equal to the threshold, MRO against abnormal intra-RAT handovers is not enabled. Abnormal handovers include both premature and delayed handovers. GUI Value Range: 0~100


MO

Parameter ID


MML Command

Feature ID

Feature Name

Description Unit: % Actual Value Range: 0~100 Default Value: 10

MRO

IntraRatTooEarlyHoRatioThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold of the proportion of Optimization(MRO) premature intra-RAT handovers. If the proportion of the premature intra-RAT handovers is higher than this threshold and the current cell individual offset (CIO) is greater than the CIO adjustment threshold, mobility parameters need to be adjusted. If the proportion of the premature intra-RAT handovers is less than or equal to this parameter value, mobility parameters do not need to be adjusted. If both this parameter and the IntraRatTooLateHoRatioThd parameter are set to 50% or smaller values, the conditions for optimizing both premature and delayed intra-RAT handovers may be met. In this c ase, delayed intra-RAT handovers, which increase the service drop rate at a higher probability than premature intra-RAT handovers, are optimized by preference. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 70

MRO

IntraRatTooLateHoRatioThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold of the proportion of Optimization(MRO) delayed intra-RAT handovers. If the proportion of the delayed intra-RAT handovers is higher than this threshold and the current cell individual offset (CIO) is less than the CIO adjustment threshold, mobility parameters need to be adjusted. If the proportion of delayed intra-RAT handovers is less than or equal to this parameter value, mobility parameters do not need to be adjusted. If both this parameter and the IntraRatTooEarlyHoRatioThd parameter are set to 50% or smaller values, the conditions for optimizing both premature and delayed intra-RAT handovers may be met. In this c ase, delayed intra-RAT handovers, which increase the service drop rate at a higher probability than premature intra-RAT handovers, are optimized by preference. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 70

CellResel

Qhyst

MOD CELLRESEL LST CELLRESEL

LBFD-00201803 Cell Selection and / TDLBFDRe-selection 00201803 Broadcast of LBFD-002009 / system information TDLBFD002009

Meaning: Indicates the hysteresis for cell reselection when RSRP values are used in the evaluation. This parameter must be set based on the slow fading characteristic of the area covered by the cell. The greater the slow fading variance is, the larger the value of this parameter must be set to. A larger value of the hysteresis results in a larger boundary of the serving cell and a lower probability of cell reselection to neighboring cells. GUI Value Range: DB0_Q_HYST(0dB), DB1_Q_HYST(1dB), DB2_Q_HYST(2dB), DB3_Q_HYST(3dB), DB4_Q_HYST(4dB), DB5_Q_HYST(5dB), DB6_Q_HYST(6dB), DB8_Q_HYST(8dB), DB10_Q_HYST(10dB), DB12_Q_HYST(12dB), DB14_Q_HYST(14dB), DB16_Q_HYST(16dB), DB18_Q_HYST(18dB), DB20_Q_HYST(20dB), DB22_Q_HYST(22dB), DB24_Q_HYST(24dB) Unit: dB Actual Value Range: DB0_Q_HYST, DB1_Q_HYST, DB2_Q_HYST, DB3_Q_HYST, DB4_Q_HYST, DB5_Q_HYST, DB6_Q_HYST, DB8_Q_HYST, DB10_Q_HYST, DB12_Q_HYST, DB14_Q_HYST, DB16_Q_HYST, DB18_Q_HYST, DB20_Q_HYST, DB22_Q_HYST, DB24_Q_HYST Default Value: DB4_Q_HYST(4dB)

EutranIntraFreqNCell

CellQoffset

ADD EUTRANINTRAFREQNCELL MOD EUTRANINTRAFREQNCELL LST EUTRANINTRAFREQNCELL

LBFD-00201801 Coverage Based / TDLBFDIntra-frequency 00201801 Handover

Meaning: Indicates the offset for the intra-frequency neighboring cell, which is used in evaluation for cell reselections. A larger value of this parameter results in a lower probability of cell reselections. If this p arameter is not set to dB0, it is delivered in SIB4. For details, see 3GPP TS 36.331. If this parameter is set to dB0, it is not delivered in SIB4. In this situation, UEs use 0 dB as the offset for cell reselections. For details, see 3GPP TS 36.304. GUI Value Range: dB-24(-24dB), dB-22(-22dB), dB-20(-20dB), dB-18(-18dB), dB-16(-16dB), dB-14(-14dB), dB-12(-12dB), dB-10(-10dB), dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB), dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB), dB1(1dB), dB2(2dB),


MO

Parameter ID


MML Command

Feature ID

Feature Name

Description dB3(3dB), dB4(4dB), dB5(5dB), dB6(6dB), dB8(8dB), dB10(10dB), dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB), dB20(20dB), dB22(22dB), dB24(24dB) Unit: dB Actual Value Range: dB-24, dB-22, dB-20, dB-18, dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4, dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5, dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20, dB22, dB24 Default Value: dB0(0dB)

Cell

CellSpecificOffset

ADD CELL MOD CELL LST CELL

LBFD-00201801 Coverage Based / TDLBFDIntra-frequency 00201801 Handover TDLBFD002018

Mobility Management

TDLBFD00201802

Coverage Based Inter-frequency Handover

TDLBFD00201804 TDLBFD00201805 TDLOFD001019 TDLOFD001043 TDLOFD001072 TDLOFD001020 TDLOFD001046 TDLOFD001073

Distance Based Inter-frequency Handover Service Based Inter-frequency Handover

Meaning: Indicates the cell specific offset for the serving cell. It affects the probability of triggering handovers from the serving cell to its neighboring cells. A smaller value of this parameter leads to a higher probability. For details, see 3GPP TS 36.331. GUI Value Range: dB-24(-24dB), dB-22(-22dB), dB-20(-20dB), dB-18(-18dB), dB-16(-16dB), dB-14(-14dB), dB-12(-12dB), dB-10(-10dB), dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB), dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB), dB1(1dB), dB2(2dB), dB3(3dB), dB4(4dB), dB5(5dB), dB6(6dB), dB8(8dB), dB10(10dB), dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB), dB20(20dB), dB22(22dB), dB24(24dB) Unit: dB


Actual Value Range: dB-24, dB-22, dB-20, dB-18, dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4, dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5, dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20, dB22, dB24

Service based Inter-RAT handover to UTRAN

Default Value: dB0(0dB)

Distance based Inter-RAT handover to UTRAN PS Inter-RAT Mobility between E-UTRAN and GERAN Service based Inter-RAT handover to GERAN Distance based Inter-RAT handover to GERAN

IntraFreqHoGroup

In traF req Ho A3 Off set

A DD I NTR AFR EQ HOG ROU P LBFD-00201801 Coverage Based / TDLBFDIntra-frequency MOD 00201801 Handover INTRAFREQHOGROUP LST INTRAFREQHOGROUP

Meaning: Indicates the offset for event A3. If the parameter is set to a large value, an intra-frequency handover is performed only when the signal quality of the neighboring cell is significantly better than that of the serving cell and other triggering conditions are met. For details, see 3GPP TS 36.331. GUI Value Range: -30~30 Unit: 0.5dB Actual Value Range: -15~15 Default Value: 2

IntraFreqHoGroup

IntraFreqHoA3Hyst

ADD INTRAFREQHOGROUP LBFD-00201801 Coverage Based / TDLBFDIntra-frequency MOD 00201801 Handover INTRAFREQHOGROUP LST INTRAFREQHOGROUP

Meaning: Indicates the hysteresis for intra-frequency handover event A3. This parameter decreases frequent event triggering due to radio signal fluctuations and reduces the probability of handover decision errors and ping-pong handovers. A larger value of this parameter results in a lower probability. The hysteresis for event inter-frequency handover event A3 is the same as the value of this parameter. For details, see 3GPP TS 36.331. GUI Value Range: 0~30 Unit: 0.5dB Actual Value Range: 0~15 Default Value: 2

EutranIntraFreqNCell

CellIndividualOffset

ADD EUTRANINTRAFREQNCELL MOD EUTRANINTRAFREQNCELL LST EUTRANINTRAFREQNCELL

LBFD-00201801 Coverage Based / TDLBFDIntra-frequency 00201801 Handover TDLBFD002018

Mobility Management

Meaning: Indicates the cell individual offset for the intrafrequency neighboring cell, which is used in evaluation for handovers. It affects the probability of triggering intrafrequency measurement reports. A larger value of this parameter indicates a higher probability. For details, see 3GPP TS 36.331. GUI Value Range: dB-24(-24dB), dB-22(-22dB), dB-20(-20dB), dB-18(-18dB), dB-16(-16dB), dB-14(-14dB), dB-12(-12dB), dB-10(-10dB), dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB), dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB), dB1(1dB), dB2(2dB), dB3(3dB), dB4(4dB), dB5(5dB), dB6(6dB), dB8(8dB),


MO

Parameter ID


MML Command

Feature ID

Feature Name

Description dB10(10dB), dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB), dB20(20dB), dB22(22dB), dB24(24dB) Unit: dB Actual Value Range: dB-24, dB-22, dB-20, dB-18, dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4, dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5, dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20, dB22, dB24 Default Value: dB0(0dB)

MRO

InterFreqMeasTooLateHoThd MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the percentage threshold of delayed Optimization(MRO) handovers caused by low threshold of the event A2 and delayed inter-frequency measurements to the sum of premature handovers and delayed handovers. If the actual percentage is greater than this parameter value, the threshold for triggering inter-frequency event A2 is adjusted by the inter-frequency MRO. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 5

CellMro

InterFreqA2RsrpLowLimit


LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the lower limit used to adjust the Optimization(MRO) reference signal received power (RSRP) threshold for triggering inter-frequency event A2. GUI Value Range: -140~-43 Unit: dBm Actual Value Range: -140~-43 Default Value: -115

CellMro

InterFreqA2RsrpUpLimit


LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the upper limit used to adjust the Optimization(MRO) reference signal received power (RSRP) threshold for triggering inter-frequency event A2. GUI Value Range: -140~-43 Unit: dBm Actual Value Range: -140~-43 Default Value: -99

CellMro

A3InterFreqA2RsrpLowLimit


LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the lower limit used to adjust the Optimization(MRO) reference signal received power (RSRP) threshold for triggering A3-oriented inter-frequency event A2. GUI Value Range: -140~-43 Unit: dBm Actual Value Range: -140~-43 Default Value: -115

CellMro

A3InterFreqA2RsrpUpLimit


LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the upper limit used to adjust the Optimization(MRO) reference signal received power (RSRP) threshold for triggering A3-oriented inter-frequency event A2. GUI Value Range: -140~-43 Unit: dBm Actual Value Range: -140~-43 Default Value: -89

MRO

PingpongRatioThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold for the percentage of Optimization(MRO) intra-RAT ping-pong handovers. If the percentage of intra-RAT ping-pong handovers i s greater than this parameter value, parameters are adjusted to reduce the number of ping-pong handovers. If the percentage is less than or equal to this parameter value, parameters are not adjusted. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 5

MRO

NcellOptThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the handover success rate threshold Optimization(MRO) for enabling mobility-related parameter optimization. If the handover success rate is greater than this parameter value, mobility-related parameters are optimized to reduce the number of ping-pong handovers. GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 99

MRO

UePingPongNumThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold for the number of Optimization(MRO) pingpong handovers. If the number of consecutive ping-pong handovers reaches the threshold, the UE is a ping-pong UE. GUI Value Range: 1~7 Unit: None Actual Value Range: 1~7 Default Value: 5


MO

Parameter ID

CellMro

CioAdjLowerLimit


MML Command

Feature ID

Feature Name

MOD CELLMRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the lower limit of cell i ndividual offset Optimization(MRO) (CIO) adjustment range for the cell in mobility robustness optimization (MRO). This parameter needs to be set only when the CioAdjLimitCfgInd parameter is set to CFG.

LST CELLMRO

Description

GUI Value Range: dB-24(-24dB), dB-22(-22dB), dB-20(-20dB), dB-18(-18dB), dB-16(-16dB), dB-14(-14dB), dB-12(-12dB), dB-10(-10dB), dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB), dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB), dB1(1dB), dB2(2dB), dB3(3dB), dB4(4dB), dB5(5dB), dB6(6dB), dB8(8dB), dB10(10dB), dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB), dB20(20dB), dB22(22dB), dB24(24dB) Unit: dB Actual Value Range: dB-24, dB-22, dB-20, dB-18, dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4, dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5, dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20, dB22, dB24 Default Value: dB-24(-24dB) CellMro

CioAdjUpperLimit


LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the upper limit of cell i ndividual offset Optimization(MRO) (CIO) adjustment range for the cell in mobility robustness optimization (MRO). This parameter needs to be set only when the CioAdjLimitCfgInd parameter is set to CFG. GUI Value Range: dB-24(-24dB), dB-22(-22dB), dB-20(-20dB), dB-18(-18dB), dB-16(-16dB), dB-14(-14dB), dB-12(-12dB), dB-10(-10dB), dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB), dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB), dB1(1dB), dB2(2dB), dB3(3dB), dB4(4dB), dB5(5dB), dB6(6dB), dB8(8dB), dB10(10dB), dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB), dB20(20dB), dB22(22dB), dB24(24dB) Unit: dB Actual Value Range: dB-24, dB-22, dB-20, dB-18, dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4, dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5, dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20, dB22, dB24 Default Value: dB24(24dB)

CellMro

CioAdjLimitCfgInd


LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Optimization(MRO) Indicates whether to set the upper and lower limits of the CIO adjustment range for the cell. If this parameter is set to CFG(Configure), the CIO for the cell can be changed by an amount within the range specified by the upper and lower limits. If this parameter is set to NOT_CFG(Not configure), the upper and lower limits of the CIO adjustment range for the cell in intra-frequency MRO are calculated by using the following formulas: Lower limit = Off + Ofs + Ocs Ofn + Hys - 5, Upper limit = Off + Ofs + Ocs - Ofn + Hys - 2, where Off i s the offset f or intra-frequency handover, Ofs and Ofn are the frequency-specific offsets for the serving frequency and neighboring frequency respectively, Ocs is the cell-specific offset for the serving cell, and Hys is the hysteresis for intra-frequency handover. If this parameter is set to NOT_CFG(Not configure) and the Inter-Freq HO trigger Event Type parameter is set to EventA4(EventA4), the upper and lower limits of the CIO adjustment range for the cell in inter-frequency MRO are calculated by using the following formulas: Lower limit = -24, Upper limit < thresh + 110 - Ofn + Hys, where thresh is the RSRP threshold for triggering a coverage-based inter-frequency handover and Hys is the hysteresis for inter-frequency handover. If this parameter is set to NOT_CFG(Not configure) and the Inter-Freq HO trigger Event Type parameter is set to EventA3(EventA3), the upper and lower limits of the CIO adjustment range for the cell in inter-frequency MRO are calculated by using the following formulas: Lower limit = Off + Ofs + Ocs - Ofn + Hys - 5, Upper limit = Off + Ofs + Ocs - Ofn + Hys - 2, where Off is the inter-frequency A3 offset, and Hys is the hysteresis for intra-frequency handover. GUI Value Range: NOT_CFG(Not configure), CFG(Configure) Unit: None Actual Value Range: NOT_CFG, CFG Default Value: NOT_CFG(Not configure)

MRO

In terF req A2Ro ll Bac kT hd

M OD M RO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold of event A2 rollback Optimization(MRO) triggered by inter-frequency MRO. If the percentage of too late handovers caused by late inter-frequency measurement to the sum of too early handovers and too late handovers is less than the threshold, the event A2 rollback is triggered.


MO


Parameter ID

MML Command

Feature ID

Feature Name

Description GUI Value Range: 0~100 Unit: % Actual Value Range: 0~100 Default Value: 2

MRO

InterRatStatNumThd

MOD MRO LST MRO

LOFD-002005 / TDLOFD002005

Mobility Robust Meaning: Indicates the threshold of the number of Optimization(MRO) handovers (including outgoing handover attempts and delayed handovers) required for enabling optimization of inter-RAT mobility-related parameters. Optimization of inter-RAT mobility-related parameters is started when the number of handovers from the local cell to inter-RAT neighboring cells reaches this threshold. GUI Value Range: 0~10000 Unit: None Actual Value Range: 0~10000 Default Value: 1000

CellMro

LocalCellId

LST CELLMRO

None

None

MOD CELLMRO

Meaning: Indicates the local ID of the cell. It uniquely identifies a cell within an eNodeB. GUI Value Range: 0~255 Unit: None Actual Value Range: 0~255 Default Value: None

10 Counters Table 10-1 Counters Counter ID

Counter Name

Counter Description

Feature ID

Feature Name

1526726989

L.IRATHO.E2W.PrepAttOut

Number of inter-RAT handover attempts from E-UTRAN to WCDMA network

Multi-mode: MRFD-101401

UL Unified Video Steering

GSM: None LTE: LOFD-001019


LOFD-001022

CS Fallback to UTRAN

LOFD-001033 TDLOFD-001019


TDLOFD-001022

SRVCC to UTRAN

TDLOFD-001033


Multi-mode: MRFD-101401

UL Unified Video Steering

GSM: None UMTS: None


LTE: LOFD-001019

SRVCC to UTRAN

LOFD-001022


LOFD-001033 TDLOFD-001022


TDLOFD-001033


Multi-mode: None GSM: None


UMTS: None

SRVCC to GERAN

LTE: LOFD-001020 LOFD-001023

CS Fallback to GERAN

1526726991

L.IRATHO.E2W.ExecSuccOut

Number of successful inter-RAT handovers from E-UTRAN to WCDMA network

UMTS: None

TDLOFD-001019

1526726992

L.IRATHO.E2G.PrepAttOut

Number of inter-RAT handover attempts from E-UTRAN to GERAN

LOFD-001034


TDLOFD-001020

SRVCC to GERAN

TDLOFD-001023


TDLOFD-001034 1526726994

L.IRATHO.E2G.ExecSuccOut

Number of successful inter-RAT handovers from E-UTRAN to GERAN

Multi-mode: None GSM: None


UMTS: None

SRVCC to GERAN

LTE: LOFD-001020


LOFD-001023 LOFD-001034


TDLOFD-001020

SRVCC to GERAN

TDLOFD-001023


TDLOFD-001034 1526727378

L.Traffic.User.Avg

Average number of users in a cell

Multi-mode: None

RRC Connection Management

GSM: None

RRC Connection Management

UMTS: None LTE: LBFD-002007 TDLBFD-002007 1526728173

L.HHO.Ncell.PingPongHo

Number of ping-pong handovers Multi-mode: None between two specific cells GSM: None UMTS: None LTE: LBFD-00201801 LBFD-00201802

Coverage Based Intrafrequency Handover Coverage Based Interfrequency Handover PS Inter-RAT Mobility between


Counter ID


Counter Name

Counter Description

Feature ID

Feature Name

LOFD-001019

E-UTRAN and UTRAN

LOFD-001020


LOFD-001021 TDLBFD-00201801 TDLBFD-00201802 TDLOFD-001019 TDLOFD-001020 TDLOFD-002005 LOFD-002005

PS Inter-RAT Mobility between E-UTRAN and CDMA2000 Coverage Based Intra-frequency Handover Coverage Based Inter-frequency Handover PS Inter-RAT Mobility between E-UTRAN and UTRAN PS Inter-RAT Mobility between E-UTRAN and GERAN Mobility Robust Optimization (MRO) Mobility Robust Optimization (MRO)

1526728355

L.HHO.NCell.HoToolate

Number of delayed intra-RAT handovers between two specific cells

Multi-mode: None GSM: None UMTS: None LTE: LOFD-002005

Mobility Robust Optimization (MRO) Mobility Robust Optimization (MRO)

TDLOFD-002005 1526728356

L.HHO.NCell.HoTooearly

Number of premature intra-RAT handovers between two specific cells



TDLOFD-002005 1526728952

L.HHO.NCell.HoToWrgCell

Number of intra-RAT handovers to a wrong cell between two specific cells

Multi-mode: None GSM: None UMTS: None LTE: TDLOFD-002005


LOFD-002005 1526728953

L.HHO.NCell.HoToWrgCell.HoSucc

Number of successful intra-RAT handovers to a wrong cell between two specific cells



LOFD-002005 1526729053

L.HHO.NCell.A2MeasHOTooLate

Number of A2-related delayed intra-RAT handovers



TDLOFD-002005 1526733169

L.HHO.NCell.PingPongHo.Consecutive

Number of consecutive ping-pong handovers between two specific cells



LOFD-002005 1526733170

1526733171

L.HHO.NCell.UeMro.Cio

L.MeasCtrl.InterFreqA3.Coverage.Num.Total

Number of times that the anti-ping-pong-handover parameter CIO is sent in two specific cells based on UE-level MRO


Number of inter-frequency Multi-mode: None measurement configurations for GSM: None event A3 UMTS: None TDLBFD-00201802 LOFD-002005 TDLOFD-002005

L.MeasCtrl.InterFreqA4A5.Coverage.Num.Total Number of inter-frequency Multi-mode: None measurement configurations for GSM: None event A4/A5 sent due to UMTS: None coverage LTE: LBFD-00201802 TDLBFD-00201802 LOFD-002005 TDLOFD-002005

1526737680

L.IRATHO.E2U.HoTooLate

Number of delayed EUTRANto-UTRAN handovers


LOFD-002005

LTE: LBFD-00201802

1526733172


Multi-mode: None GSM: None UMTS: None LTE: LOFD-002005 TDLOFD-002005

Coverage Based Interfrequency Handover Coverage Based Interfrequency Handover Mobility Robust Optimization (MRO) Mobility Robust Optimization (MRO) Coverage Based Interfrequency Handover Coverage Based Interfrequency Handover Mobility Robust Optimization (MRO) Mobility Robust Optimization (MRO) Mobility Robust Optimization (MRO) Mobility Robust Optimization (MRO)

MRO Feature Parameter Description

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