ERAN6.0 Capacity Monitoring Guide 10(PDF)-En

eRAN6.0

Capacity Monitoring Guide Issue

10

Date

2014-08-27

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2014. 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.

Trademarks and Permissions and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd. All other trademarks and trade names mentioned mentioned in this document are the property of of their respective respective holders. holders.

Notice The purchased products, services and features are stipulated by the contract made between Huawei and the customer. All or part of the products, services and features described in this document document may not be within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information, information, and recommendations in this document are provided "AS IS" without warranties, guarantees or representations of any kind, either express or implied. The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations recommendations in this document do not constitute a warranty of any kind, express or implied.

Huawei Technologies Co., Ltd. Address:

Huawei Industrial Industrial Base Bantian, Longgang Shenzhen 518129 People's Republic of China

Website:

http://www.huawei.com

Email:

[email protected]

Issue 10 (2014-08-27)

Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd.

i

Copyright © Huawei Technologies Co., Ltd. 2014. 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.

Trademarks and Permissions and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd. All other trademarks and trade names mentioned mentioned in this document are the property of of their respective respective holders. holders.

Notice The purchased products, services and features are stipulated by the contract made between Huawei and the customer. All or part of the products, services and features described in this document document may not be within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information, information, and recommendations in this document are provided "AS IS" without warranties, guarantees or representations of any kind, either express or implied. The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations recommendations in this document do not constitute a warranty of any kind, express or implied.

Huawei Technologies Co., Ltd. Address:

Huawei Industrial Industrial Base Bantian, Longgang Shenzhen 518129 People's Republic of China

Website:

http://www.huawei.com

Email:

[email protected]

Issue 10 (2014-08-27)


i

eRAN6.0 Capacity Monitoring Guide

About This Document

About This Document

Purpose This document describes the networking and protection of SDH, PDH, Ethernet, ATM, SAN and video services. In addition, network management information, orderwire and clock planning is described briefly. This document provides guides to get the information about how to construct a network. NOTE l

For details about the MML commands, parameters, alarms, and performance counters, see section "Operation and Maintenance" in 3900 Series Base Station Product Documentation for 3900 series base station, "BTS3202E Product Documentation" for BTS3202E base station, and "BTS3203E LTE Product Documentation" for BTS3203E base station.

l

The main control, transmission, and baseband processing units are deployed on the same board and share the CPU for BTS3202E and BTS3203E LTE. The main control board and baseband board in this document are corresponding units in BTS3202E and BTS3203E LTE. The CPU usage of the main control board is the CPU usage of boards in BTS3202E and BTS3203E LTE.

l

This document does not apply to scenarios where a large amount of traffic volume is involved. For guidance in these scenarios, contact Huawei technical support.

Product Versions The following table lists the product version related to this document.

Product Name

Solution Version

BTS3900

l

SRAN8.0

l

eRAN6.0

BTS3900A

Product Version V100R008C00

BTS3900L BTS3900AL DBS3900 BTS3202E BTS3203E LTE

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V100R006C00

ii


About This Document

Intended Audience This document is intended for: l l

Field engineers Network planning engineers engineers

Organization 1 Changes in eRAN Capacity Monitoring Guide

This section describes changes in each issue of this document. 2 Overview

This chapter describes the types of network resources to be monitored and the method of performing capacity capacity monitoring. 3 Capacity Monitoring 4 Resource Allocation Allocation Problem Identification Identification

This chapter describes how to identify resource allocation problems. Network abnormalities can be found found through KPI monitoring. If a KPI is deteriorated, deteriorated, users can can analyze analyze the access access counters counters (RRC resource congestion rate and E-RAB resource congestion rate) to check whether the deterioration is caused by resource congestion. 5 Related Counters Counters

Conventions Symbol Conventions

The symbols that may be found in this document are defined as follows.

Symbol

Description Indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury. Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury.

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About This Document

Symbol

Description Indicates a potentially hazardous situation which, if not avoided, could result in equipment damage, data loss, performance deterioration, or unanticipated results. NOTICE is used to address practices not related to personal injury. Calls attention to important information, best practices and tips. NOTE is used to address information not related to personal injury, equipment damage, and environment deterioration.

General Conventions

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Italic

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Command Conventions

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Italic

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[]

Items (keywords or arguments) in brackets [ ] are optional.

{ x | y | ... }

Optional items are grouped in braces and separated by vertical bars. One item is selected.

[ x | y | ... ]

Optional items are grouped in brackets and separated by vertical bars. One item is selected or no i tem is selected.

{ x | y | ... } *

Optional items are grouped in braces and separated by vertical bars. A minimum of one item or a maximum of all items can be selected.

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About This Document

Convention

Description

[ x | y | ... ] *

Optional items are grouped in brackets and separated by vertical bars. Several items or no item can be selected.

GUI Conventions

The GUI conventions that may be found in this document are defined as follows.

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Boldface

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>

Multi-level menus are in boldface and separated by the ">" signs. For example, choose File > Create > Folder.

Keyboard Operations

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Format

Description

Key

Press the key. For example, press Enter and press Tab.

Key 1+Key 2

Press the keys concurrently. For example, pressing Ctrl+Alt +A means the three keys should be pressed concurrently.

Key 1, Key 2

Press the keys in turn. For example, pressing Alt, A means the two keys should be pressed in turn.

Mouse Operations

The mouse operations that may be found in this document are defined as follows.

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Action

Description

Click

Select and release the primary mouse button without moving the pointer.

Double-click

Press the primary mouse button twice continuously and quickly without moving the pointer.

Drag

Press and hold the primary mouse button and move the pointer to a certain position.


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Contents

Contents About This Document.....................................................................................................................ii 1 Changes in eRAN Capacity Monitoring Guide.......................................................................1 2 Overview.........................................................................................................................................7 2.1 Network R esources.........................................................................................................................................................8 2.2 Capacity Monitoring Methods......................................................................................................................................10

3 Capacity Monitoring...................................................................................................................11 3.1 Introduction..................................................................................................................................................................12 3.2 Downlink User Perception............................................................................................................................................14 3.3 Synchronized User Capacity Usage.............................................................................................................................15 3.4 PRACH R esource Usage..............................................................................................................................................16 3.5 PDCCH R esource Usage..............................................................................................................................................17 3.6 Connected User License Usage....................................................................................................................................19 3.7 Traffic Volume License Usage.....................................................................................................................................20 3.8 Paging Resource Usage................................................................................................................................................20 3.9 Main-Control-Board CPU Usage.................................................................................................................................21 3.10 Baseband Processing Unit CPU Usage......................................................................................................................22 3.11 Transpor t Resource Group Usage...............................................................................................................................24 3.12 Ethernet Port Traffic...................................................................................................................................................25

4 Resource Allocation Problem Identification..........................................................................28 4.1 Resource Congestion Indicators...................................................................................................................................29 4.1.1 RRC Resource Congestion Rate................................................................................................................................29 4.1.2 E-RAB Resource Congestion Rate............................................................................................................................29 4.2 Resource Allocation Problem Identification Process...................................................................................................30

5 Related Counters.........................................................................................................................32

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1 Changes in eRAN Capacity Monitoring Guide

1

Chang es in eRAN Capacity Monitoring Guide This section describes changes in each issue of this document.

10 (2014-08-27) This is the tenth commercial release. Compared with issue 09 (2014-04-15), this issue does not include any new information. Compared with issue 09 (2014-04-15), this issue includes the following changes.

Topic

Change History

ALL

Optimized the description.

No information in issue 09 (2014-04-15) is deleted from this issue.

09 (2014-04-15) This is the ninth commercial release. Compared with issue 08 (2014-03-14), this issue does not include any new information. Compared with issue 08 (2014-03-14), this issue includes the following changes.

Topic

Change History

3.9 Main-Control-Board CPU Usage

Modified the formula of "Percentage of times that the maincontrol-board CPU usage reaches or exceeds a preconfigured threshold (85%)."

3.10 Baseband Processing Unit CPU Usage

No information in issue 08 (2014-03-14) is deleted from this issue. Issue 10 (2014-08-27)


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08 (2014-03-14) This is the eighth commercial release. Compared with issue 07 (2013-12-23), this issue includes the following new information. l

3.3 Synchronized User Capacity Usage

l

3.7 Traffic Volume License Usage

Compared with issue 07 (2013-12-23), this issue includes the following changes.

Topic

Change History

3.1 Introduction

Modified Table 2-1.

3.2 Downlink User Perception

Changed the monitoring item to downlink user perception, and modified the monitoring principles and the suggested measures.

3.5 PDCCH Resource Usage

Modified the monitoring principles, monitoring methods, and suggested measures.

3.8 Paging Resource Usage

l

Deleted the monitoring item L.Paging.Dis.Num.

l

Added suggested measures for the core network.

3.9 Main-Control-Board CPU Usage

Modified the suggested measures.

3.11 Transport Resource Group Usage

Cancel the monitoring of packet loss rate.


07 (2013-12-23) This is the seventh commercial release. Compared with issue 06 (2013-10-30), this issue does not include any new information. Compared with issue 06 (2013-10-30), this issue includes the following changes.

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Topic

Change History

3.1 Introduction

Added the restriction on the application scope of this document.

2.2 Capacity Monitoring Methods

Added the principle of defining resource consumption thresholds.


Changed the monitoring item to downlink user perception, and modified the monitoring principles.


2



Compared with issue 06 (2013-10-30), this issue includes the following changes. l

SRS Resource Usage: The SRS subframe reconfiguration switch is turned on by default. SRS resources will not become the network bottleneck and therefore will not be monitored.

l

PUCCH Resource Usage: The PUCCH algorithm switch is turned on by default. PUCCH resources will not become the network bottleneck and therefore will not be monitored.

06 (2013-10-30) This is the sixth commercial release. Compared with issue 05 (2013-08-26), this issue includes the following new information. l

5 Related Counters


Topic

Change History


l

Modified formulas for measuring the monitoring items.

l

Added the suggested measures and the conditions for taking measures.

SRS Resource Usage

l

Modified the maximum number of UEs supported by SRS resources when the system bandwidth is 10 MHz.

l

Modified suggested measures when the SRS resource usage exceeds 60%.

l

Modified the value of N in the formula for calculating random preamble usage when the system bandwidth is 5 MHz or 10 MHz.

l

Added a suggested measure: enabling PRACH resource adjustment algorithm if required.

3.4 PRACH Resource Usage

PUCCH Resource Usage

Modified suggested measures when the PUCCH resource usage exceeds 60%.


Modified formulas for measuring the monitoring items.

3.12 Ethernet Port Traffic

Added the bandwidth that operators configure for the BTS3202E and the BTS3023E LTE board, and modified the unit of bandwidth.

4 Resource Allocation Problem Identification

Added the congestion rate threshold. Optimized the resource allocation problem identification process.


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"eNodeB Resources" and "Cell Resources": Deleted these two sections. The contents in these sections are described in Table 2-1, which contains four columns: Resource Type, Meaning, Impact of Resource Insufficiency on the System, and Monitoring Item.


3

eRAN6.0 Capacity Monitoring Guide l


"General Process": Deleted this section. The thresholds for the resources to be monitored and the related handling suggestions are described in Table 3-1. The counters involved in capacity monitoring formulas are provided in 5 Related Counters.

05 (2013-08-26) This is the fifth commercial release. Compared with issue 04 (2013-07-22), this issue does not include any new information. Compared with issue 04 (2013-07-22), this issue includes the following changes.

Topic

Change History


Modified paging specifications of the BTS3202E and BTS3203E.


04 (2013-07-22) This is the fourth commercial release. Compared with issue 03 (2013-06-26), this issue includes the following new information. l



Topic

Change History


Added the figure to illustrate the position of Transport Resource Group in TCP/IP model.

eNodeB Resources

Modified the description of Main-control-board CPU, LBBP CPU, transport resource group and Ethernet port.


Modified the suggested measures.


03 (2013-06-26) This is the third commercial release. Compared with issue 02 (2013-05-27), this issue does not include any new information. Compared with issue 02 (2013-05-27), this issue includes the following changes.

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Topic

Change History


Added the suggested measures when the uplink or downlink PRB usage reaches or exceeds 90%.

SRS Resource Usage

Added the SFN cell scenarios.

2.2 Capacity Monitoring Methods

Modified the figure.

4.2 Resource Allocation Problem Identification Process

Modified the problem identification flow chart.


02 (2013-05-27) This is the second commercial release. Compared with issue 01 (2013-04-28), this issue does not include any new information. Compared with issue 01 (2013-04-28), this issue includes the following changes.

Topic

Change History

3 Capacity Monitoring

Added the descriptions about how to query parameter values.

4.1 Resource Congestion Indicators

Added counters related to KPIs.

3.1 Introduction

Modified tables.


Appendix

01 (2013-04-28) This is the first commercial release. Compared with Draft A (2012-12-30), this issue does not include any new information. Compared with Draft A (2012-12-30), this issue includes the following changes.

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Topic

Change History

Appendix

Added the description about how to query resource-related data.


5



Topic

Change History

2 Overview

Optimized the general process of capacity monitoring and handling.


Revised the description according to the template.


Revised the description according to the template.

No information in Draft A (2012-12-30) is deleted from this issue.

Draft A (2012-12-30) This is the first draft.

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2 Overview

2

Overview

About This Chapter This chapter describes the types of network resources to be monitored and the method of performing capacity monitoring. 2.1 Network Resources 2.2 Capacity Monitoring Methods

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2 Overview

2.1 Network Resources Figure 2-1 shows the network resources to be monitored. Figure 2-1 Network resources to be monitored

Table 2-1 describes the types of network resources to be monitored and impacts of resource insufficiency on the system. Table 2-1 Network resources

Resource Type

Cell resources

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Physical resource blocks (PRBs)

Meaning

Impact of Resource Insufficiency on the System

Resource Monitoring Item

Bandwidth consumed on the air interface

Users may fail to be admitted, and experience of admitted users is affected.



8


2 Overview

Resource Type

eNodeB resources

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Meaning



Synchronized user capacity

Maximum number of synchronized users in a cell

User experience is affected.

3.3 Synchronized User Capacity Usage

Physical random access channel (PRACH) resources

Random access preambles carried on the PRACH

Access delays are prolonged, or even access attempts fail.

3.4 PRACH Resource Usage

Physical downlink control channel (PDCCH) resources

Downlink control channel resources

Uplink and downlink scheduling delays are prolonged, and user experience is affected.


RRC connected user license

Maximum New services permissible cannot be number of users admitted, and in experience of RRC_CONNE admitted users is CTED mode affected.

3.6 Connected User License Usage

Traffic volume license

Maximum traffic volume in an eNodeB

User experience and customer income are affected.


Paging resources

eNodeB paging capacity

Paging messages may be lost, affecting user experience.


Main-control board CPU

Processing capability of the main control board of the eNodeB

KPIs deteriorate.

3.9 MainControl-Board CPU Usage

Baseband processing unit CPU

Processing capability of the baseband processing unit

KPIs deteriorate.

3.10 Baseband Processing Unit CPU Usage


9


2 Overview

Resource Type

Meaning



Transport resource groups

eNodeB logical transport resources

Packets may be lost, affecting user experience.


Ethernet ports

eNodeB physical transport resources

Packets may be lost, affecting user experience.

3.12 Ethernet Port Traffic

2.2 Capacity Monitoring Methods Capacity monitoring can be implemented using the following two methods: l

Daily monitoring for prediction: Counters are used to indicate the load or usage of various types of resources on the LTE network. Thresholds for resource consumption are specified so that preventive measures such as reconfiguration and expansion can be taken to prevent network congestion when the consumption of a type of resource continually exceeds the threshold. For details, see 3 Capacity Monitoring.

l

Problem-driven analysis: This method helps identify whether a problem indicated by counters is caused by network congestion through in-depth analysis. With this method, problems can be precisely located so that users can work out a proper network optimization and expansion solution. For details, see 4 Resource Allocation Problem Identification. NOTE

l

Thresholds defined for capacity monitoring in this document are generally lower than those for alarm triggering so that risks of resource insufficiency can be detected as early as possible.

l

Thresholds given in this document apply to networks experiencing a steady growth. Thresholds are determined based on product specifications and experiences in working with existing networks. For example:

l

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l

The CPU usage threshold 60% is specified based on the CPU flow control threshold 80%.

l

The eNodeB's RRC connected user license usage threshold 60% is specified based on the peak-toaverage ratio (about 1.5:1). When the average usage reaches 60%, the peak usage approaches 100%. Threshold determining considers both average and peak values.

Telecom operators are encouraged to formulate an optimization solution for resource capacity based on prediction and analysis for networks that are experiencing fast development, scheduled to deploy new services, or about to employ new charging plans. If you require services related to resource capacity optimization, such as prediction, evaluation, optimization, reconfiguration, and capacity expansion, contact Huawei technical support.


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3

Capacity Monitoring

About This Chapter

3.1 Introduction This chapter describes monitoring principles and methods, as well as related counters, of all types of service resources. Information about how to locate resource bottlenecks and the related handling suggestions are also provided. 3.2 Downlink User Perception 3.3 Synchronized User Capacity Usage 3.4 PRACH Resource Usage 3.5 PDCCH Resource Usage 3.6 Connected User License Usage 3.7 Traffic Volume License Usage 3.8 Paging R esource Usage 3.9 Main-Control-Board CPU Usage 3.10 Baseband Processing Unit CPU Usage 3.11 Transport Resource Group Usage 3.12 Ethernet Port Traffic

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3.1 Introduction This chapter describes monitoring principles and methods, as well as related counters, of all types of service resources. Information about how to locate resource bottlenecks and the related handling suggestions are also provided. Note that resource insufficiency may be determined by usage of more than one type of service resource. For example, a resource bottleneck can be claimed only when both RRC connected user license usage and main-control- board CPU usage exceed the predefined thresholds. NOTE

You need to determine busy hours of the system for accurate monitoring of counters. You are advised to define busy hours as a period when the system or a cell is undergoing the maximum resource consumption of a day.

Table 3-1 describes types of resources to be monitored, thresholds, and handling suggestions. Table 3-1 Types of resources to be monitored, thresholds, and handling suggestions

Resource Resour Type ce Monito ring Item Cell resources

3.2 Downlink PRB usage ≥ Downlin 70% and downlink userk User perceived rate < 2 Mbit/s Percepti (default value, useron configurable) 3.3 Synchro nized User Capacit y Usage

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Conditions

Synchronized user capacity usage ≥ 60%

Handling Suggestions

Optimize RF performance, expand the cell bandwidth, and add carriers or eNodeBs.

Take one of the following measures: l

Optimize parameters.

l

Optimize RF performance.

l

Expand the cell bandwidth.

l

Add carriers.

l

Split cells.

3.4 PRACH Resourc e Usage

Usage of preambles for contention-based access ≥ 75%

Enable the backoff algorithm for the PRACH.

Usage of preambles for non-contention-based access ≥ 75%

Enable the PRACH resource adjustment algorithm and reuse of dedicated preambles.

3.5 PDCCH Resourc e Usage

CCE usage ≥ 80%

Set PDCCH Symbol Number Adjust Switch to ON(On).

PDCCH Symbol Number Adjust Switch is set to OFF (Off)


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Resource Resour Type ce Monito ring Item

eNodeB resources


PDCCH Symbol Number Adjust Switch is set to ON (On), and uplink or downlink PRB usage ≥ 70%

Take one of the following measures:

Main-control board CPU usage < 60%

Add licenses.

Main-control board CPU usage ≥ 60%

Add eNodeBs.

l

Add carriers.

l

Split cells.

l

Optimize radio frequency (RF) performance.

3.6 Connect ed User License Usage

RRC connecte d user license usage ≥ 60%


Traffic volume license usage of an eNodeB ≥ 80%

Increase the licensed traffic volume.

3.8 Paging Resourc e Usage

Percentage of paging messages received on the S1 interface ≥ 60%


3.9 MainControl -Board CPU Usage

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Conditions

l

l

Average main-control board CPU usage ≥ 60%, or Percentage of times that the CPU usage reaches or exceeds 85% ≥ 5%

l

Decrease the number of cells in t he tracking area list (TAL) that the congested cell belongs to.

l

Adjust the paging policy of the core network to reduce signaling overhead.

l

If the core network is provided by Huawei, enable the precise paging function.

Take one of the following measures: l l

l


Make the loads balance. Use boards with higher specifications to replace old boards. Add eNodeBs.

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Resource Resour Type ce Monito ring Item

Conditions

Average baseband processing unit CPU usage ≥ 60%, or

3.10 Baseban d Processi ng Unit CPU Usage

l

3.11 Transpo rt Resourc e Group Usage

l

Proportion of average transmission rate to configured bandwidth ≥ 80%, or

l

Proportion of maximum transmission rate to configured bandwidth ≥ 90%

3.12 Etherne t Port Traffic

Proportion of average transmission rate to allocated bandwidth ≥ 70% or Proportion of maximum transmission rate to allocated bandwidth ≥ 85%

l

Percentage of times that the CPU usage reaches or exceeds 85% ≥ 5%


Take one of the following measures: l

Add boards.

l

Use boards with higher specifications to replace old boards.

l

Make the inter-BBP loads balance.

Expand the bandwidth of the transport resource group.

Expand the eNodeB transmission capacity.

3.2 Downlink User Perception Monitoring Principles Growing traffic leads to a continuous increase in PRB usage. When the PRB usage approaches to 100%, user-perceived rates will decrease. As downlink is a major concern in an LTE network, this document describes only how to monitor downlink user perception. NOTE

The uplink user perception can be monitored using the same way.

Monitoring Methods The following items are used in monitoring this case: l

Downlink PRB usage L.ChMeas.PRB.DL.Used.Avg/L.ChMeas.PRB.DL.Avail x 100%

l

Downlink user-perceived r ate (Mbit/s) = L.Thrp.bits.DL/L.Thrp.Time.DL/1000

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where: l

L.ChMeas.PRB.DL.Used.Avg indicates the average number of used downlink PRBs.

l

L.ChMeas.PRB.DL.Avail indicates the number of available downlink PRBs.

l

L.Thrp.bits.DL indicates the total throughput of downlink data transmitted at the PDCP layer in a cell.

l

L.Thrp.Time.DL indicates the duration for transmitting downlink data at the PDCP layer in a cell.

Suggested Measures If both of the following conditions are met: l

Downlink PRB usage ≥ 70%

l

Downlink user-perceived rate < a user-defined threshold (default value: 2 Mbit/s)

Then: l

If the cell spectral efficiency is low, you are advised to increase the cell throughput by optimizing RF performance.

l

If the cell spectral efficiency is high, you are advised to: – Add carriers or expand the bandwidth of the existing carrier. – Add eNodeBs.

3.3 Synchronized User Capacity Usage Monitoring Principles When the number of RRC connected users in a cell exceeds the maximum number defined in the product specifications, cell KPIs deteriorate. RRC connected users include synchronized users and users in the out-of-synchronization state. Synchronized users consume air interface resources and the number of synchronized users is approximately equal to the number of RRC connected users by default. Therefore, the number of RRC connected users (instead of synchronized users) is monitored. NOTE

When the number of RRC connected users in a cell reaches or exceeds the preconfigured threshold, the user perceived rate has already decreased to an unacceptable level. Therefore, the user-perceived rate should be considered first. The number of RRC connected users in a cell can be considered first when the user capacity of a cell takes priority over user experience.

Monitoring Methods The following item is used in monitoring this case: ynchronized user capacity usage of a cell = L.Traffic.User.Avg/ Maximum number of synchronized users in a cell x 100% where l

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L.Traffic.User.Avg indicates the average number of RRC connected users in a cell. Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd.

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The maximum number of synchronized users in a cell is 400 for the LBBPc or 1200 for the LBBPd.

Suggested Measures When the synchronized user capacity usage of a local cell reaches or exceeds 60%, you are advised to: l

Release UEs in idle mode as early as possible: Reduce the UE inactivity timer length by running the MOD RRCCONNSTATETIMER command with the UeInactiveTimer parameter specified. This measure lifts signaling overhead and increases CPU usage.

l

Transfer UEs out of the local cell: If a neighboring cell is lightly loaded, adjust the antenna downtilt angle or decrease the transmit power of the local cell to shrink the coverage area and reduce the number of users in the l ocal cell. In addition, expand the coverage area of the neighboring cell for load balancing.

l

Add cells or expand the local cell bandwidth.

l

Split the local cell into multiple cells

3.4 PRACH Resource Usage Monitoring Principles The PRACH transmits preambles during random access procedures. If the number of contention-based random access attempts in a second reaches or exceeds N, the preamble conflict probability and access delay increase. The values of N are determined during preamble design, considering factors such as that the preamble conflict probability should be less than 1%. If more than 100 non-contention-based random access attempts are initiated per second, dedicated preambles will become insufficient and the eNodeB will instruct the UE to initiate contention-based random access instead, increasing the access delay for the UE. In handover scenarios, the handover procedure is prolonged.

Monitoring Methods The following items are used in monitoring t his case: l

Random preamble usage = (L.RA.GrpA.Att + L.RA.GrpB.Att)/3600/N x 100%

l

Dedicated preamble usage = L.RA.Dedicate.Att/3600/100 x 100%

where l

L.RA.GrpA.Att indicates the number of times that random preambles in group A are received.

l

L.RA.GrpB.Att indicates the number of times that random preambles in group B are received.

l

L.RA.Dedicate.Att indicates the number of times that dedicated preambles are received.

l

The value of N varies as follows: – If the system bandwidth is 15 MHz or 20 MHz, N is 100.

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– If the system bandwidth is 5 MHz or 10 MHz and the PRACH resource adjustment

algorithm is disabled, N is 50. – If the system bandwidth is 5 MHz or 10 MHz and the PRACH resource adjustment

algorithm is enabled, N is 100. To check whether the PRACH resource adjustment algorithm is enabled, run the LST CELLALGOSWITCH command to query the value of the RachAlgoSwitch.

Suggested Measures You are advised to take the following measures: l

f the random preamble usage reaches or exceeds 75% for X days (three days by default) in a week, enable the adaptive backoff function by running the following command to help reduce the peak RACH load and average access delay: MOD CELLALGOSWITCH: LocalCellId=x, RachAlgoSwitch=BackOffSwitch-1;

If the system bandwidth is 5 MHz or 10 MHz, it is good practice to enable the PRACH resource adjustment algorithm by running the following command: MOD CELLALGOSWITCH: LocalCellId=x,RachAlgoSwitch=RachAdjSwitch-1; l

If the dedicated preamble usage reaches or exceeds 75% for X days (three days by default) in a week, enable the PRACH resource adjustment algorithm and reuse of dedicated preambles between UEs by running the following command: MOD CELLALGOSWITCH: LocalCellId=x,RachAlgoSwitch= RachAdjSwitch-1,RachAlgoSwitch=MaksIdxSwitch-1;

This helps reduce the probability of UEs initiating contention-based random access in the case of dedicated preamble insufficiency and therefore helps reduce the access delay.

3.5 PDCCH Resource Usage Monitoring Principles This capacity indicator measures the number of control channel elements (CCEs) that can be used by the PDCCH. l

If PDCCH symbols are insufficient or the cell is heavily loaded, CCEs may fail to be allocated to UEs to be scheduled, which will result in a long service delay and unsatisfactory user experience.

l

If PDCCH symbols are excessive and the cell is lightly loaded, the resources that can be used by the PDSCH increases. This will also result in low spectral efficiency.

Monitoring Methods The following item is used in monitoring this case: CCE usage = (L.ChMeas.CCE.CommUsed + L.ChMeas.CCE.ULUsed + L.ChMeas.CCE.DLUsed)/3600/1000/ Max number of PDCCH CCEs x 100% where l

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L.ChMeas.CCE.CommUsed indicates the number of PDCCH CCEs used for common signaling. Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd.

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l

L.ChMeas.CCE.ULUsed indicates the number of PDCCH CCEs used for uplink scheduling.

l

L.ChMeas.CCE.DLUsed indicates the number of PDCCH CCEs used for downlink scheduling.

l

Maximum number of PDCCH CCEs is defined in the following table. Table 3-2 Maximum number of PDCCH CCEs

System Bandwidth (Configurabl e)

Ng

5 MHz

10 MHz

15 MHz

20 MHz

Maximum Number of PDCCH CCEs Number of PDCCH Symbols = 1

Number of PDCCH Symbols = 2

Number of PDCCH Symbols = 3

1/6

4

13

21

1/2

4

12

21

1

3

12

20

2

2

11

19

1/6

10

26

43

1/2

9

26

42

1

8

25

41

2

6

23

39

1/6

15

40

65

1/2

14

39

64

1

12

37

62

2

9

34

59

1/6

20

54

87

1/2

19

52

86

1

17

50

84

2

13

46

80

In the preceding table: – The number of PDCCH symbols depends on the PDCCH Symbol Number Adjust

Switch parameter value, which can be queried by running the LST CELLPDCCHALGO command: – If the parameter value is Off , the number of PDCCH symbols is equal to the PDCCH

Initial Symbol Number parameter value, which can be queried by running the LST CELLPDCCHALGO command. Issue 10 (2014-08-27)


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3 Capacity Monitoring – The value of Ng is equal to the PHICH resource parameter value, which can be

queried by running the LST PHICHCFG command.

Suggested Measures l

If the PDCCH Symbol Number Adjust Switch parameter value is Off , you are advised to set this parameter to On by running the following command: MOD CELLPDCCHALGO: LocalCellId=x, PdcchSymNumSwitch=ON;

l

If the PDCCH Symbol Number Adjust Switch parameter value is set to On and the uplink or downlink PRB usage reaches or exceeds 70%, you are advised to take one of the following measures: – Add cells or split existing cells. – Optimize RF performance to reduce the interference to PDCCH from neighboring cells.

3.6 Connected User License Usage Monitoring Principles The RRC connected user license specifies the maximum permissible number of users in RRC_CONNECTED mode. If the RRC connected user license usage exceeds a preconfigured threshold, users may fail to access the network.

Monitoring Methods The following item is used in monitoring this case: RRC connected user license usage = ∑L.Traffic.User.Avg/ Licensed number of RRC connected users x 100% where l

L.Traffic.User.Avg indicates the average number of RRC connected users in a cell. ∑ L.Traffic.User.Avg indicates the sum of the average number of RRC connected users in all cells under an eNodeB.

l

The licensed number of RRC connected users can be queried by running the following command: DSP LICENSE: FUNCTIONTYPE=eNodeB;

In the command output, the value of LLT1ACTU01 in the Allocated column is the licensed number of RRC connected users.

Suggested Measures Measures to be taken also depend on the main-control-board CPU usage. If the RRC connected user license usage reaches or exceeds 60% for X days (three days by default) in a week, you are advised to take the following measures: l

If the main-control-board CPU usage is less than 60%, increase the licensed limit.

l

If the main-control-board CPU usage reaches or exceeds 60%, add an eNodeB.

For details about main-control-board CPU usage, see section 3.9 Main-Control-Board CPU Usage. Issue 10 (2014-08-27)


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3.7 Traffic Volume License Usage Monitoring Principles When the traffic volume of an eNodeB reaches or exceeds the licensed volume, the eNodeB performs flow control, which affects user experience and customer income.

Monitoring Methods The following item is used in monitoring this case: Traffic volume license usage of an eNodeB = ∑(L.Thrp.bits.UL+L.Thrp.bits.DL)/( Licensed eNodeB traffic volume x 3600) x 100% where l

L.Thrp.bits.UL and L.Thrp.bits.DL indicate the uplink traffic volume and downlink traffic volume of a cell, respectively. ∑(L.Thrp.bits.UL+L.Thrp.bits.DL) indicates the sum of uplink and downlink traffic volume of all cells under an eNodeB.

l

The licensed eNodeB traffic volume can be queried by running the following command: DSP LICENSE: FUNCTIONTYPE=eNodeB;

The licensed eNodeB traffic volume is equal to the Allocated parameter value in the record whose License Identifier is LLT1THRUL01 .

Suggested Measures If the traffic volume license usage of an eNodeB reaches or exceeds 80% for X days (three days by default) in a week, you are advised to increase the licensed traffic volume.

3.8 Paging Resource Usage Monitoring Principles The eNodeB and BTS3202E and BTS3203E LTE can process a maximum of 750 and 500 paging messages per second, respectively. If the number of paging messages exceeds that capacity, paging messages sent from the eNodeB to UEs may be discarded, which leads to a decrease in the call completion rate.

Monitoring Methods The following item is used in monitoring this case: Percentage of paging messages received over the S1 interface = L.Paging.S1.Rx/3600/ Maximum number of paging messages that can be processed per second x 100% In the preceding formula, L.Paging.S1.Rx indicates the number of paging messages received over the S1 interface. Issue 10 (2014-08-27)


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Suggested Measures If the percentage of paging messages received by the eNodeB over the S1 interface reaches or exceeds 60% for X days (three days by default) in a week, you are advised to: l

Decrease the number of cells in the tracking area list (TAL) that the congested cell belongs to.

l

Adjust the paging policy of the core network. That is, reduce the number of paging messages sent after the first or second paging failures to reduce signaling overhead.

l

Enable the precise paging function if the core network is provided by Huawei.

3.9 Main-Control-Board CPU Usage Monitoring Principles The CPU usage of the main control board reflects the busy level of the eNodeB. If the maincontrol-board CPUs are busy processing control plane or user plane data, signaling-related KPIs may deteriorate, and users may experience a low access success rate, low E-RAB setup success rate, or high service drop rate. Operators can determine whether signaling-related KPI deterioration is caused by insufficient main-control-board CPU processing capability or poor radio conditions. The evaluation is as follows: l

If the CQI related performance counters indicate that the channel quality is poor, KPI deterioration may not be caused by main-control-board CPU overload but by deterioration in channel quality.

l

If the KPIs deteriorate and the main-control-board CPU usage exceeds a preconfigured threshold, you are advised to perform capacity expansion according to "Suggested Measures."

Monitoring Methods The following items are used in monitoring t his case: l l

VS.Board.CPUload.Mean Percentage of times that the main-control-board CPU usage reaches or exceeds a preconfigured threshold (85%) = VS.Board.CPULoad.CumulativeHighloadCount/ (3600/5) x 100%

where l

VS.Board.CPUload.Mean indicates the average main-control-board CPU usage.

l

VS.Board.CPULoad.CumulativeHighloadCount indicates the number of times that the main-control-board CPU usage exceeds a preconfigured threshold.

Suggested Measures The main-control-board CPU of a local eNodeB becomes overloaded if either of the following conditions is met for X days (three days by default) in a week: Issue 10 (2014-08-27)


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l

VS.Board.CPUload.Mean reaches or exceeds 60%.

l

The percentage of times that the main-control-board CPU usage reaches or exceeds 85% is greater than or equal to 5%.


l

Transfer UEs from the eNodeB: If a neighboring eNodeB is lightly loaded, adjust the antenna downtilt angles or decrease the transmit power of the local eNodeB to shrink the coverage area and reduce the CPU load of the local eNodeB. In addition, expand the coverage area of the neighboring eNodeB for load balancing.

l

Replace the main control board with a UMPT: If the main control board is an LMPT, replace it with a UMPT.

l

Add eNodeBs.

3.10 Baseband Processing Unit CPU Usage Monitoring Principles If the eNodeB receives too much traffic, which is expressed either in bit/s or packet/s, the baseband processing unit CPU responsible for user plane processing is heavily loaded. As a result, the eNodeB has a low RRC connection setup success rate, low E-RAB setup success rate, low handover success rate, and high service drop rate.

Monitoring Methods The following item is used in monitoring this case:

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Percentage of times that the baseband processing unit CPU usage reaches or exceeds a preconfigured threshold (85%) = VS.Board.CPULoad.CumulativeHighloadCount/ (3600/5) x 100%

where l

VS.Board.CPUload.Mean indicates the average baseband processing unit CPU usage.

l

VS.Board.CPULoad.CumulativeHighloadCount indicates the number of times that the baseband processing unit CPU usage exceeds a preconfigured threshold.

Suggested Measures The baseband processing unit CPU becomes overloaded if either of the following conditions is met for X days (three days by default) in a week: l

The average baseband processing unit CPU usage reaches or exceeds 60%.

l

The percentage of times that the baseband processing unit CPU usage reaches or exceeds 85% is greater than or equal to 5%.

When the CPU usage of baseband processing unit is high, you are advised to perform capacity expansion as follows:

l

Migrate cells in the eNodeB. If the eNodeB has multiple baseband processing units and one of them is overloaded, move cells from the overloaded baseband processing unit to a baseband processing unit with a lighter load. Baseband processing unit load can be indicated by the following: – Average CPU usage – Percentage of times that the CPU usage reaches or exceeds a preconfigured threshold

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– Number of cells established on a baseband processing unit l

Substitute a baseband processing unit with high specifications for one with low specifications. For example, if the baseband processing unit is an LBBPc, replace the LBBPc with an LBBPd or a UBBP. If the baseband processing unit is an LBBPd, replace the LBBPd with a UBBP.

l

If the eNodeB has a vacant slot, add a baseband processing unit to share the network load, and then move existing cells to the new baseband processing unit.

l

Add an eNodeB: If the eNodeB already has the maximum number of baseband processing units and more baseband processing units are required, add an eNodeB.

3.11 Transport Resource Group Usage Monitoring Principles A transport resource group carries a set of data streams, which can be local data or forwarded data. Local data is classified into control plane, user plane, operation and maintenance (OM), and IP clock data. Forwarded data is not divided into different types. If a transport resource group is congested, it cannot transmit or forward data, which affects service provision. A transport resource group for user plane data is a monitored object. Figure 3-1 shows the position of transport resource group in the TCP/IP model. Figure 3-1 The position of the transport resource group


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Proportion of the average transmission rate to the configured bandwidth = VS.RscGroup.TxMeanSpeed/Bandwidth configured for the transport resource group x 100%


24



Proportion of the maximum transmission rate to the configured bandwidth = VS.RscGroup.TxMaxSpeed/Bandwidth configured for the transport resource group x 100%

where l

VS.RscGroup.TxMeanSpeed indicates the average transmission rate of a transport resource group.

l

VS.RscGroup.TxMaxSpeed indicates the maximum transmission rate of a transport resource group.

l

The bandwidth configured for a transport resource group can be queried by running the following command: DSP RSCGRP: CN=x, SRN=x, SN=x, BEAR=xx, SBT=xxxx, PT=xxx;

In the command output, the value of Tx Bandwidth is the bandwidth configured for the transport resource group.

Suggested Measures A transport resource group is congested if one of the following conditions is met: l

The proportion of the average transmission rate to the configured bandwidth reaches or exceeds 80% for five days in a week.

l

The proportion of the maximum transmission rate to the configured bandwidth reaches or exceeds 90% for two days in a week.

When a transport resource group is congested, you are advised to expand the bandwidth of the transport resource group. The following is an example command: MOD RSCGRP: CN=x, SRN=x, SN=x, BEAR=IP, SBT=BASE_BOARD, PT=ETH, PN=x, RSCGRPID=x, RU=x, TXBW=xxxx, RXBW=xxxx;

If the problem persists after the bandwidth adjustment, you are advised to expand the eNodeB bandwidth.

3.12 Ethernet Port Traffic Monitoring Principles The Ethernet port traffic is the channel traffic at the physical layer, including uplink and downlink traffic. The eNodeB Ethernet port traffic reflects the throughput and communication quality of the Ethernet ports on the main control board of the eNodeB. Based on the monitoring results, you can determine whether the transmission capacity allocated by an operator for the S1 and X2 interfaces on the eNodeB meet the requirements for uplink and downlink transmissions.


Issue 10 (2014-08-27)

(Item 1) Proportion of the average uplink transmission rate to the allocated bandwidth = VS.FEGE.TxMeanSpeed/Allocated bandwidth x 100% Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd.

25



l

(Item 2) Proportion of the maximum uplink transmission rate to the allocated bandwidth = VS.FEGE.TxMaxSpeed/Allocated bandwidth x 100%

l

(Item 3) Proportion of the average downlink reception rate to the allocated bandwidth = VS.FEGE.RxMeanSpeed/Allocated bandwidth x 100%

l

(Item 4) Proportion of the maximum downlink reception rate to the allocated bandwidth = VS.FEGE.RxMaxSpeed/Allocated bandwidth x 100%

where l

VS.FEGE.TxMeanSpeed indicates the average transmission rate of an Ethernet port.

l

VS.FEGE.TxMeanSpeed indicates the average transmission rate of an Ethernet port.

l

VS.FEGE.TxMaxSpeed indicates the maximum transmission rate of an Ethernet port.

l

VS.FEGE.RxMeanSpeed indicates the average reception rate of an Ethernet port.

l

VS.FEGE.RxMaxSpeed indicates the maximum reception rate of an Ethernet port.

l

The allocated bandwidth can be queried by referring to Table 3-3.

Table 3-3 Allocated bandwidth

Value of LR Switch

Main Control Board

Allocated Bandwidth

Disable

UMPT

Min(1.5 Gbit/s, the transmission bandwidth of the Ethernet port)

LMPT

l

For items 1 and 2: 300 Mbit/s

l


Boards in BTS3202E and BTS3203E LTE

l


l


UMPT

l

For items 1 and 2: value of UL Committed Information Rate (Kbit/s)

l

For items 3 and 4: value of DL Committed Information Rate (Kbit/s)

Enable

LMPT Boards in BTS3202E and BTS3203E LTE

l

You can run the LST LR command to query the values of LR Switch, UL Committed Information Rate (Kbit/s), and DL Committed Information Rate (Kbit/s).

l

The types of main control boards can be queried by running the following command: DSP BRD: CN=x, SRN=x, SN=x;

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In the command output, the value of Config Type is the type of the main control board.

Suggested Measures You are advised to perform transmission capacity expansion if either of the following conditions is met: l

The proportion of the average uplink transmission rate (or downlink reception rate) to the allocated bandwidth reaches or exceeds 70% for at least five days in a week. The actually allocated bandwidth can be obtained from the operator.

l

The proportion of the maximum uplink transmission rate (or downlink reception rate) to the allocated bandwidth reaches or exceeds 85% for at least two days in a week.

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4

Resource Allocation Problem Identification

About This Chapter This chapter describes how to identify resource allocation problems. Network abnormalities can be found through KPI monitoring. If a KPI is deteriorated, users can analyze the access counters (RRC resource congestion rate and E-RAB resource congestion rate) to check whether the deterioration is caused by resource congestion. 4.1 Resource Congestion Indicators 4.2 Resource Allocation Problem Identification Process

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4.1 Resource Congestion Indicators Resource congestion indicators (such as the RRC resource congestion rate and E-RAB resource congestion rate) can be used to check whether the network is congested. Table 4-1 lists the counters related to KPIs. Table 4-1 Counters related to KPIs

Performance Counter

Description

L.RRC.ConnReq.Att

Number of RRC Connection Request messages received from UEs in a cell (excluding retransmitted messages)

L.RRC.ConnReq.Succ

Number of RRC Connection Setup Complete messages received from UEs in a cell

L.E-RAB.AttEst

Number of E-UTRAN radio access bearer (E-RAB) setup attempts initiated by UEs in a cell

L.E-RAB.SuccEst

Number of successful E-RAB setups initiated by UEs in a cell

L.E-RAB.AbnormRel

Number of times that the eNodeB abnormally releases E-RABs that are transmitting data in a cell

L.E-RAB.NormRel

Number of times that the eNodeB normally releases E-RABs in a cell

4.1.1 RRC Resource Congestion Rate The RRC resource congestion rate is a cell-level indicator. It is calculated using the following formula: RRC resource congestion rate = L.RRC.SetupFail.ResFail/L.RRC.ConnReq.Att x 100% where l

L.RRC.SetupFail.ResFail indicates the number of RRC connection setup failures due to resource allocation failures.

l

L.RRC.ConnReq.Att indicates the number of RRC connection setup requests.

If the RRC resource congestion rate is higher than 0.2%, KPI deterioration is caused by resource congestion.

4.1.2 E-RAB Resource Congestion Rate The E-RAB resource congestion rate is a cell-level indicator. It is calculated using the following formula: E-RAB resource congestion rate = L.E-RAB.FailEst.NoRadioRes/L.E-RAB.AttEst x 100% Issue 10 (2014-08-27)


29



where l

L.E-RAB.FailEst.NoRadioRes indicates the number of E-RAB setup failures due to radio resource insufficiency.

l

L.E-RAB.AttEst indicates the number of E-RAB setup attempts.

If the E-RAB resource congestion rate is higher than 0.2%, KPI deterioration is caused by resource congestion.

4.2 Resource Allocation Problem Identification Process Figure 4-1 shows the Resource Allocation Problem Identification Process. Figure 4-1 Resource allocation problem identification process

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The fault location procedure begins with the identification of abnormal KPIs, followed up by selecting and performing a KPI analysis on the top N cells. Cell congestion mainly results from insufficient system resources. Bottlenecks can be detected by analyzing the access counters (RRC resource congestion rate and E-RAB resource congestion rate).

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5 Related Counters

5

Related Counters

Table 5-1 lists counters involved in capacity monitoring. Table 5-1 Counters involved in capacity monitoring

Resource Type

Counter Name

Description

PRBs

L.ChMeas. PRB.DL.Used.Avg

Average number of used downlink PRBs

L.ChMeas.PRB.DL.Avail

Number of available downlink PRBs

L.Thrp.bits.DL

Total downlink traffic volume for PDCP SDUs in a cell

L.Thrp.Time.DL

Total transmit duration of downlink PDCP SDUs in a cell

L.RA.GrpA.Att

Number of times the contention preamble in group A is received

L.RA.GrpB.Att

umber of times the contention preamble in group B is received

L.RA.Dedicate.Att

Number of times the non-contention based preamble is received

L.ChMeas.CCE.CommUsed

Number of PDCCH CCEs used for common DCI

L.ChMeas.CCE.ULUsed

Number of PDCCH CCEs used for uplink DCI

L.ChMeas.CCE.DLUsed

Number of PDCCH CCEs used for downlink DCI

L.ChMeas.CCE.Avail

Number of available CCEs

PRACH resources

PDCCH resources

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ERAN6.0 Capacity Monitoring Guide 10(PDF)-En

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