01 GUL Interworking Principal & Solution Introduction V1.1

GUL Interworking Principal & Solution Introduction

HUAWEI TECHNOLOGIES CO., LTD.

1

GUL Interworking Background & Challenges

2

GUL Idle Mode/Connected Mode/CSFB/MLB

3

GUL Interworking KPI Introduction


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Page 2

Typical Network Deployment Trend Network Deployment Strategy

O operation in A Country

2015

L2300(TDD-20M) L2300(TDD-20M) L2600(FDD-20M) L1800(FDD-15M) L700(FDD-10M)

U2100(20M) U900(4.2M) G900(4.2M)

Different RAT used for Coverage & Capacity layer, Increases Network complexity & interworking problems


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Typical Network Top and Structure IRAT interworking, especially applied in the LTE early establishment stage, while the coverage not continues and no voice barer network (IMS). The typical network structure as follows:

The following is typical GUL network coverage : GSM with widest coverage, UMTS and LTE with hotpot coverage, solutions needed for UE power on, register, handover requirement.

UMTS

LTE

LTE UMTS

GSM


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Operator’s Problems 1. Cell edge coverage not good enough, which network to camp? 2. How to keep continuous service in connecting status?

Which network to camp？

L2600 L1800

L2600

L1800

L800

U2100

L1800

Heavy load cell

L800

U2100 U900

G900/1800

U2100 U900

How to balance cell load, increase user experience?

G900/1800

1. How to adjust idle strategies to balance traffic load when connected. 2. How to raise efficiency of new network(LTE e.g)?


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Complicate network situation: Multi

mode, multi freq.



Different coverage with different freq.



New network cannot get a perfect coverage



Cell load is too heavy for hot spot or dense

area

Facing problems

Idle mode camping

1）In multi mode and multi freq. network, which network to camp? 2）How to reselect when coverage is not good?

Service continuity

How to keep service continuity when user is in cell edge?

Load balance

When cell load is heavy, how to balance between cells belonged to different freq/mode.

Traffic layer

1）How to keep voice service continuous from LTE network? 2）What is the traffic layer strategy within UMTS network? 3）What is the traffic layer strategy between GSM and UMTS?

Page 5

1


2


3



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Inter-working Solution Overview(1/2) Idle mode solution

Traffic continuity solution

Terminal optimized

Basic Solutions

CS&PS service seamless

camping & seamless

 Idle mode solution

between different network

reselection between modes

 Traffic continuity solution

LTE coverage solution

and freq.

Necessary solution for every

UMTS coverage solution

 inter network camping

network

GSM coverage solution

 intra network camping

Broad pipe Load balance solution Raise network internetwork efficiency GSM heavy load solution UMTS heavy load solution

LTE heavy load solution HUAWEI TECHNOLOGIES CO., LTD.

Option Solutions

Traffic layer solution Traffic steered to suitable network, to get better user experiences & capacity GU Traffic layer solution L->U CSFB solution UMTS intra network Traffic layer solution Huawei Confidential

 Load balance solution  Traffic layer solution To choose based on terminal

penetration, network load, operator requirement.

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Inter-working Solution Overview(2/2) Base on the SW version and UE ability, 3 stages suggested as follows :

Idle mode mobility

LTE/EPC PS service mobility

UMTS

Voice service mobility

•

VoIP through IMS is agreed as target voice solution of LTE

•

CSFB is migration solution before VoIP over LTE is available (IMS deployment and terminal supporting VoIP/SRVCC are available) and CSFB would co-exist with

Cell Reselection

Step1

 Blind Redirection

+ Measurement

Step 2 + PSHO

CSFB over Blind Redirection

VoIP when VoIP is deployed. •

SRVCC supports the LTE VoIP handover to UMTS CS Voice when out of LTE

Step1

Step2

coverage •

If VoIP is implemented over HSPA, only PS handover for LTE to UMTS voice continuity


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Step3

GU Version Required & UE recommended for Probe Test System

Target RAN ability

Required Version

Suggested Version

GSM to LTE reselection

GBSS12.0

GBSS14.0

LTE to GSM PSHO

GBSS12.0

GBSS14.0

LTE to GSM CCO/NACC

GBSS12.0

GBSS14.0

LTE to GSM SRVCC

GBSS12.0

GBSS14.0

UMTS to LTE reselection

RAN 12

RAN 14

LTE to UMTS PSHO

RAN 13

RAN 14

LTE to UMTS SRVCC

RAN 15

RAN 15

GSM

UMTS


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Recommended UE for Probe Test： Samsung S5，G620sL01/L02/L03

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1.Idle Mode Reselection


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Idle Mode Camping Solution (1/2) Camping 1. Cell edge coverage not good enough, which network to camp? 2. How to keep continuous service in connecting status?

Which network to camp？

L2600 L1800

U2100

Multi-mode camping strategies

LTE camping prior, if no LTE or bad LTE coverage, reselect to UMTS; If no UMTS or weak UMTS coverage, reselect to GSM.

GU dual-mode Camping strategies

UMTS prior camping, If no UMTS or weak UMTS coverage, reselect to GSM.

L2600

L1800

L800

solution

L1800 L800

U2100 U900

G900/1800

U2100 U900 G900/1800

Heavy load cell How to balance cell load, increase user experience?

Single mode Camping strategies

1. How to adjust idle strategies to balance traffic load when connected. 2. How to raise efficiency of new network


LTE intra system camping UMTS intra system camping GSM intra system camping

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Idle Mode Camping Solution (2/2) High

Single mode Camping strategies L2600

L1800

L1800

Priority1

L800

U2100

U2100

U900

Priority3

7

10

7

U900

2 G900/1800

8

4

8

The same frequency with the same priority

Scenario 2: traffic layer in UMTS network： Recommend to camp in R99 carrier.

G900/1800

Coverage

Mode priority



Scenario 1: without traffic layer：  The UE preferentially camp on the carrier with contiguous coverage. If all carriers’ coverage are contiguous, the UE randomly camp on any cell.  Both U900 and U2100 are contiguous coverage, choose U2100 for camping or random camping

U2100

1

High frequency with high priority for camping

UMTS camping strategies：

5

L800

Priority2

Priority3

Priority2

L1800

6



Priority1

L2600

9

High

LTE camping strategies：

Frequency priority

Cell reselection

GSM camping strategies： • The same frequency with the same priority • High frequency TRX with high priority

Priority tip: Different system priority cannot be same.


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Inter-working Key Features No.

ID

Feature

Release

1 1

GBFD-114301

GSM/WCDMA Interoperability

2 2

GBFD-511301

Cell Reselection Between GSM and LTE GBSS12.0

GL cell reselection based on neighbor level and mode priority.

3 3

WRFD-010401

RAN 2.0

Support handover between different frequency.

4 4

WRFD-020303

System Information Broadcasting Inter-RAT Handover Based on Coverage

RAN2.0

Handover Based on Coverage

5 5

WRFD-020126

Mobility Between UMTS and LTE Phase RAN12.0 1

Cell selection and reselection between UMTS and LTE ; LTE to UMTS PS handover

6 6

LBFD-00201803

Cell Selection and Re-selection

eRAN1.0

LTE intra system Cell selection and reselection

7 7

LOFD-001019

PS Inter-RAT Mobility between EUTRAN and UTRAN

eRAN1.0

L2U Cell selection and reselection Based on Coverage

8 8

LOFD-001020

9 9 10 10

LBFD-00201802 WRFD-020302

GBSS6.0

Description

PS Inter-RAT Mobility between EeRAN1.0 UTRAN and GERAN Coverage Based Inter-frequency eRAN2.0 Handover Inter Frequency Hard Handover Based RAN2.0 on Coverage

U2G reselection or handover; G2U reselection or handover

L2G Cell selection and reselection Based on Coverage LTE intra system Cell selection and reselection Based on Coverage UMTS intra system Cell selection and reselection Based on Coverage

*The features above comply with the protocols, can interconnect with networks by other vendors. So as the features below, except features with special remarks.


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Cell Reselection Principle for absolute priority Measure：Srxlev<=SnonIntraSearchP or Squal<=SnonIntraSearchQ

SservingCell is worse than Thresh_serving.low &

SNonservingCell is better than Thresh_x.low Cell Reselection High Prio. eNodeB

SNonservingCell is better than Thresh_x.high

Low Prio. eNodeB/BTS

LTE

SIB

(High)

UMTS

SIB

(Medium)

GSM (Low)

Cell Reselection From High -> Low


Suggested RAT Priority:  LTE(High)  UMTS(Medium)  GSM(Low)

Cell Reselection From Low > High

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SIB

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Camping - Cell Reselection between LTE and GSM/UMTS Cell Reselection from LTE to GSM/UMTS network only when UE is out of LTE coverage area

Threshold and Measurement Threshold Threshx,high:

threshold of reselecting to High Priority Cell

Threshx,low:

threshold of reselecting to Low Priority Cell

Measurement parameter SServingCell: Signal quality of serving cell SNonServingCell:

LTE

Signal quality of target reselection cell

GSM/UMTS

Cell Reselection Strategy LTE->GSM/UMTS (High to Low)

SServingCell Threshx,low  Length of camping on serving cell > 1 sec 

Cell Reselection from GSM/UMTS to LTE network when UE enters the LTE coverage area

GSM/UMTS->LTE (Low to High)  SNonServingCell > Threshx,high 


Length of camping on serving cell > 1 sec

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Camping - Cell Reselection between GSM and UMTS Threshold and Measurement Cell Reselection from UMTS to GSM network only when UE is out of UMTS coverage area

Threshold  FDDQOFF：the

differ between UMTS candidate cell signal and GSM target cell signal  FDDQMIN：Ec/No UTRAN FDD cell reselection minimum threshold  FDD RSCP threshold  FDDRSCPMIN：UMTS cell reselection minimum threshold

Measurement parameter  RLA_C:

UMTS

GSM

GSM service cell average receive level  CPICH RSCP：UMTS neighbor cell RSCP measurement value  CPICH Ec/No：UMTS neighbor cell Ec/No measurement value

Cell Reselection Strategy

Cell Reselection from GSM to UMTS network when UE enters the UMTS coverage area


UMTS->GSM  Squal ≤ SsearchRATm  Rn > Rs GSM->UMTS  CPICH RSCP>RLA_C+FDDQOFF CPICH Ec/No≥FDDQMIN - FDDQMINOFFSET CPICH RSCP≥FDD RSCP threshold

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LTE Reselection to GU Signaling LTE Side

UMTS Side

2G接入网信令


GSM Side

3G接入网信令

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2.Connected Mode-Redirection/PS HO


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Traffic continuity solution How

to keep continuous service in connecting status, especially at the edge of different mode network?

9 L1800

L2600

L2600

L1800

L800

Three scenarios:

L1800

LTE bad Coverage

L800

7 U2100

Choose coverage based handover to other system. Adjacent cell priority: inter freq. >UMTS>GSM

U2100

7

First handover to inter freq. If no proper cell, then handover or steer to GSM

7

UMTS bad Coverage

U2100

10 U900

U900

4 G900/1800

Coverage

LTE handover based on coverage L2U PS handover based on coverage UMTS PS handover based on coverage

8

8

8

First handover to inter freq. If no proper cell, then handover or steer to UMTS.

GSM bad Coverage

G900/1800

L2G PS handover based on coverage U2G handover based on coverage


In U900 discontinuously covered network, it is recommended to handover to U2100 based on coverage. 

In U900 continuously covered network, it is NOT recommended to handover to U2100 based on coverage. 

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Data Service Mobility Solution

LTE Coverage

Data service handover (LTE->GSM/UMTS): 1. Ongoing data service is beared by LTE 2. UE handovers to GSM/UMTS 3. PS service will be on G/U PS domain

GSM/UMTS Coverage

Data service handover (GSM/UMTS->LTE):

1. Ongoing data service is beared by G/U 2. UE moves into LTE coverage area, two options for data continuity: i. Service handover to LTE directly ii. Service provided by G/U, after service ends, UE camp on LTE by cell reselection


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• Support cell reselection between eUTRAN & GERAN/UTRAN • LTE to GSM/UMTS Redirection/PS handover based on coverage in initial phase • Guarantee users’ data service quality when handover occurs • Keep network performance stable and service continuity

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Inter RAT Handover Strategy based on different Scenarios Coverage

Moves to neighbor LTE cell Moves out of LTE coverage

LTE

UMTS

Overload, offload to neighbor LTE cell

Load

LTE

UMTS

Intra-LTE Intra-LTE

Based on the radio link quality (LTE: RSRP/RSRQ) UL Quality

Inter-RAT

Based on the RB utilization (cell load) Service

√ LTE

Overload, offload to neighbor G/U cells

X

Inter-RAT UMTS

LTE

UMTS

Based on the service

Based on UL Quality • Coverage based is recommended by default at initial stage

Distance

• Load based is useful when LTE traffic significantly increased • Service based is for better utilization of each radio technologies HUAWEI TECHNOLOGIES CO., LTD.

Based on the distance bet. eNodeB & UE Huawei Confidential

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LTE To UMTS/GSM Handover Based On Coverage Description: • When the LTE signal quality is poor and the UMTS or GSM signal quality is good, UE with active PS service can be handover or redirection to the UMTS or GSM network based on UE capability, to ensure the continuity of PS services and avoid service drops. • Compared with PS redirection, PS handover shortens the service interruption duration, improving user experience.

LTE LTE Coverage Coverage L2U/G PS HO based on coverage

UMTS/GSM Coverage

Benefits: • Improves end user’s PS service experience when UE is moving out of LTE coverage Dependency: • Redirection: UE should support 3GPP R8 & UL or GL dual mode. • PS Handover: The UE should support 3GPP R8, L2U PS handovers & LTE measurements. UMTS or GSM CN and LTE CN should support LTE to UMTS or GSM PS handover

Difference between B1 & B2: B2 event requires the serving cell RSRP < A2Thresh(ERAN 8.0 support setting separately ) HUAWEI TECHNOLOGIES CO., LTD.

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Coverage-Based PS Handover/Redirection from UMTS to LTE Description: • When the UMTS signal quality is poor and the LTE signal quality is good, UE with active PS service can be handover or redirection to the LTE network based on UE capability, to ensure the continuity of PS services and avoid service drops. • Compared with PS redirection, PS handover shortens the service interruption duration, improving user experience.

LTE

PS Service

Handover/Redirection

UMTS

Benefits: • Improves end user’s PS service experience when UE is moving out of UMTS coverage Dependency: • Redirection: UE should support 3GPP R8 & UMTS/LTE dual mode. • PS Handover: The UE should support 3GPP R8, UMTS-toLTE PS handovers & LTE measurements. UMTS/LTE CN should support UMTS to LTE PS handover

Event Trigger: QUsed <= TUsed - H3a/2 & MOtherRAT >= TOtherRAT + H3a/2 Periodic report: MOtherRAT ≥ TOtherRAT + HystforPeriodLTE/2 *The feature comply with the protocols, can interconnect with networks by other vendors. It is recommended the whole network use Huawei products to avoid Ping-pong effect.


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RIM Based UMTS Target Cell Selection for LTE Description: • UMTS cell load information are transferred to LTE by

RIM procedure

LTE Cell

(1) UMTS Cell1

• In the L->U CSFB or L->U PS handover based on load, when choosing UMTS target cells, congestion cells

(2) UMTS Cell2

have the lowest priority

Benefits: • Increases the success rate of redirection & handover

Target UMTS cell congestion may cause access failure

from LTE to UMTS, reduces inter-RAT ping-pong

LTE Cell

handover. Dependency:

(1)

• UE should support flash CSFB in 3GPP R9 • CN should support RIM procedure defined in 3GPP Release 9.


Congestion

Select a suitable cell

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Congestion

UMTS Cell1

UMTS Cell2

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Inter-RAT Handover Trigger Phases • Coverage based: Event A2 : Serving cell signal quality lower than Specified threshold • Load based: MLB algorithm • Service based: UE service type. InterRatHoState to set MUST_HO, NO_HO, & PERMIT_HO. • UL Quality based: UL signal quality • Distance based: distance between eNodeB & UE

• GAP-Assisted Measurement

• LTE: RSRP/ RSRQ

• Event Triggered Periodical

• GSM: RSSI

Reporting A4/B1

• UMTS: RSCP/ECNO

• A4: Inter-frequency

• Apply for Resource (Admission) • Signalling Procedure Execution • Retry Mechanism If Admission or Handover Fail • Update Parameters to UE

• B1: Inter-RAT

Note: Coverage, Load, Service, UL-quality & Distance based inter-RAT hand over uses same procedure except for Measurement triggering phase.


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Basic Concept- Redirection Trigger Redirection reason: Coverage, MLB, off load, uplink power

Redirection is performed as RRC release with redirection indicator, making UE choose and access target cell( Realized

Redirection flow similar as reselection, but the target cell frequency,

by inter RAT measurement, or blind HO cell configured ). Redirection is controlled by RAN system, and Core Network not

system information included in RRC release message. (Based on R9)

involved. UE

restrict, S1 interface down, CSFB….

eNB

RNC

MME

SGSN

S/P-GW

1. Measurement Report

2.Handover decision

3. RRC CONNECTION RELEASE

4. UE reselect the target UTRAN cell and launch RAU procedure


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Basic Concept- PS Handover MS

Source eNodeB

Target RNC

Old MME

Serving GW

New Gn/Gp SGSN

P-GW

1. Decision to perform handover to UTRAN 2. Handover Required 3. Forward Relocation Request 4. Relocation Request Establishment of Radio Access Bearers 4. Relocation Request Acknowledge 5. Forward Relocation Response 6. Create Indirect Data Forwarding Tunnel Request 7. Create Indirect Data Forwarding Tunnel Response 8. Handover Command 9. Forwarding of data

PS Handover is with measurement , need neighbor relation

10. HO from E-UTRAN Command

configured, making PS service continuity.

MS detected by target RNC 12. Relocation Detect 13. RRC message 14. Relocation Complete 15. Forward Relocation Complete 15. Forward Relocation Complete Acknowledge 16. Update PDP Context Request 16. Update PDP Context Response 17. Routeing Area Update

C2 C3

18. Delete Session Request 18b. Release Resources 18a. Delete Session Response


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Basic Concept- PS Handover VS Redirection PS Handover

Redirection

RAN

Need all equipment software support PS handover (LTE eRAN , UMTS/GSM RAN, Core Network) ,usually need software upgrade

No need UMTS/GSM support and upgrade, but after redirection to GU, Core network should support IP context transfer , RAU procedure, and Authentication

UE

Most of UE cannot support GUL PS handover, some UE support L->U PS handover. Currently no commercial UE support GUL PS handover.

Most of UE support GUL redirection

User Experien ce

User- plane latency less than Redirection and Cell Change Order, especially for voice service

User- plane latency worse, but acceptable for PS service on user experience , and optimized in R9 with RIM.


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Case: Performance for Service Continuity Solution （K Country V Operator)


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3.Voice Solution-CSFB


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LTE Voice Solution Options

Voice & Data on LTE

IMS/SR-VCC: Voice over IMS over LTE; handover & roaming to 2G/3G is supported

IMS only*, E2012 IMS-SRVCC, 2013

OTT Mode: To rely on OTT applications for voice service offering

Not standardized Project specific

LTE Voice Solution

Data on LTE Voice on 2G/3G

CS Fallback: UE is attached on LTE, and fallback to 2G/3G for voice calls (MTC and MOC) SVLTE (Dual Standby): Dual simultaneously radio access running on the same UE allowing data on LTE and voice on 2G/3G CS in parallel


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LG Optimus, Samsung Galaxy SII HD, SK Telecom South Korea since 10-2011

Samsung Craft LTE smartphone, USA MetroPCS, Verizon since Q4-2010

Network Strategies for Delivering Voice to LTE Subscribers LTE PS Data

VoIP

2G/3G PS Data

CS Voice

2 EPC Core

EPC Core

LTE Access

LTE Access

1a Initial: Data Only   

2G/3G PS Core

2G/3G CS Core

EPC Core

2G/3G Access

LTE Access

1b

CSFB Voice

Intermediate Solution: Voice CS Fall Back

2G/3G PS Core

2G/3G CS Core

2G/3G Access

OUT of LTE

Target Solution: VoIP + SRVCC

Option 1a: To start using CSFB voice solution as an intermediate step Option 1b: To migrate to IMS/SRVCC as the target solution when it is available and mature Option 2: To straight forward move to IMS/SRVCC (SRVCC supports the LTE+IMS VoIP handover to 2G/3G CS voice when out of LTE coverage)


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CS Fallback (CSFB) Introduction Scenario: •

Internet

CSFB Principles: •

PS data

PS data LTE Core

LTE initial phase for data services, IMS is not deployed

GSM/UMTS PS Core

Handover to G/U voice service in the overlay coverage area between LTE and G/U

GSM/UMTS CS Core

•

If CSFB voice service is triggered, there are 2 options for the

pre-existing LTE data services: •

Data services are hand-over to GSM/UMTS networks (DTM supported by G/U network)

•

LTE Access

(e.g. DTM not supported)

2G/3G Access •

Voice fall back to GU

No addition Core equipment, Reuse traditional GU Core network

Voice •


SMS services do not need to fall back GSM/UMTS

Dependency: •

PS data

Data services are suspended in LTE until voice call is released

Multimode G/U/L Terminals to support CSFB

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CS Fallback: Performance and E2E Impact (UTRAN) Call Setup Latency

4.4 ~ 5.04s

Conclusion:

5.62 ~ 6.26s

•

6.58 ~ 7.22s Success Rate

Both PS handover and R9 Redirection w/ SIB (Flash

CSFB) are better realization mechanism for CSFB to UTRAN considering latency and impact for UTRAN

Impact on LTE

and UE. •

3GPP Rel9 Terminal is needed to support R9

Redirection w/ SIB. •

Impact on UTRAN

New Signaling

R8 Redirection PS Handover

CSFB with PS HO requires UMTS PS/CS software upgrade to support PS HO function

Terminal Requirement

R9 Redirection w/ SIB


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CS Fallback: Performance and E2E Impact (GERAN) Call Setup Latency

5.4 ~ 8.04s 6.8 ~ 9.44s 8.8 ~ 11.44s

Success Rate

Conclusion: •

R9 Redirection w/ SIB (Flash CSFB) is a better

realization mechanism for CSFB to GERAN

Impact on LTE

considering small change to legacy network and good success rate. •

3GPP Rel9 Terminal is needed to support R9

Redirection w/ SIB Impact on GERAN

New Signaling

R8 Redirection PS Handover

•

Current Device chipsets do not support LTE to GERAN PS handover

Terminal Requirement

R9 Redirection w/ SIB


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Flash CSFB to UTRAN/GERAN (R9 PS Redirection with SIBs) Principle: 2. RIM : RAN Information Mgt Exchange

EPC Core

5. 2G/3G RAN Information

MME

BSC/RNC

3. BSC/RNC processes RIM 1. RAN information request

4. 2G/3G RAN Information

3. RAN Information RQ

SGSN

1. eNB request system information from BSC/RNC 2. Request is sent toward core network

6. MME Direct Information Transfer

GSM/UMTS Core

4. BSC/RNC replies with updated system information 5. Core Network does not handle the message and

directly forwards it to eUTRAN 6. eNodeB does not translate the message from BSC/RNC and directly sends it to UE

7. Frequency and target cell system information

2G/3G Access

LTE Access

Flash CSFB:

7. eNodeB extracts the target frequency and related

neighboring cell information Dependency: •

procedure

• Saving 1-1.5s for UMTS compare with R8 CSFB • Saving 2s for GSM compare with R8 CSFB

Both GSM/UMTS and LTE core network support R9 RIM

•

Terminal support R9 redirection with SIB

*The feature comply with the protocols, can interconnect with networks by other vendors. The network need support RIM protocol.


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RIM Based CS Fallback MME

MSC/ SGSN

2.resource allocation

Core Network

•The MSC server and MME need to support the SGs interface. • MSCs need to support Rel.8 • MME and SGSN need to support RIM due to flash CSFB.

MSC 4. Initiate CS service

1. Voice service request

SGSN BSC/ RNC

LTE

MME

3. Fallback to GSM/UMTS with PS handover, PS redirection or flash CSFB

eNodeB/ UTRAN/GERAN

G/U

Terminal Deployment requirement:

•GUL networks support CSFB function. •Data preparation: neighbor cell, frequency, CSFB way, etc. •For incumbent vendors, it is easy to deploy without complex IOT. HUAWEI TECHNOLOGIES CO., LTD.

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Blind/With measurement: Recommended to use blind when LTE share same site with G/U. (0.3s saving on call setup time) PS HO/Redirection RIM procedure

•L to G with PS HO: None terminal support •L to U with PS HO: main stream terminal •L to G/U with Redirection: main stream terminal

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GSM/UMTS Fast Return to LTE 8s after UE idle Camp in LTE

Camp in LTE Without Fast Return

CS call on UMTS

LTE “Fast Return” Channel release with LTE frequencies

CSFB

500ms after CS call Camp in LTE With Fast Return

Camp in LTE

CS call on UMTS GSM/UMTS

•

When a Multimode UE terminates a call in GSM/UMTS network, the frequency information of LTE cell is sent in RRC Connection Release message in order to instruct the UE to camp on the LTE cell instead of cell re-selection to LTE

U->L Fast Return by PS redirection

UMTS Fast Return to LTE Cell reselection time from GSM to LTE in idle mode reduced to 480ms

GSM Fast Return to LTE HUAWEI TECHNOLOGIES CO., LTD.

Search Cycle and Cell Re-selection

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Basic Concept- CSFB flow CSFB to UMTS Based on Redirection


CSFB to UMTS Based on PS Handover

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Case: Performance for LTE Voice Solution P3 test latency and success rate reach NO.1

CSFB of Operator X in Europe Priority in idle state L1800

First to camp

L1800

L1800

1. Measured CSFB to U 2. Blind CSFB to G if no U coverage Fast return after CS call

Second to camp

Third to camp

U2100

U2100

U2100

U2100

U2100

U2100

U2100

U2100

U2100

G900/1800

G900/1800

CSFB Success rate(P3 DT): +99.6% CSFB M2M delay(P3 DT): 6.0~6.5s Compared to other vendors in the same city: NO.1


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4.IRAT MLB


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Load Balance Solution 

Avoid cell overload, get the highest efficiency of resource utility.



Raise user experiences through balancing between different mode or frequency cells L2600

First to balance inter-

L2600

11 L1800

L800

frequency, then balance to

LTE High Load L1800

UMTS or GSM

L800

First to balance interU2100 F2

U2100 F2

14

15

12 U2100 F1

U2100 F1


UMTS High Load 13

LTE or GSM

U2100 F1

16 U900

U900

First to balance inter-

U900


GSM High Load

UMTS or LTE G900/1800

G900/1800


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Inter-working Key Features No.

ID

Feature

Release

11

LOFD-001032

Intra-LTE Load Balancing

eRAN2.0

12

LOFD-001044

Inter-RAT Load Sharing to UTRAN

eRAN2.0

13

LOFD-001045

Inter-RAT Load Sharing to GERAN

eRAN2.0

WRFD-020120

Service Steering and Load Sharing in RRC Connection RAN11.0 Setup

WRFD-02040004

Traffic Steering and Load Sharing During RAB Setup

RAN10.0

WRFD-020103

Inter Frequency Load Balance

RAN3.0

WRFD-150217

Load Based PS Handover from UMTS to LTE

RAN15.0

WRFD-020120

Service Steering and Load Sharing in RRC Connection RAN11.0 Setup

WRFD-020306

Inter-RAT Handover Based on Load

RAN3.0

WRFD-020310

3G/2G Common Load Management

RAN10.0

WRFD-070004*

Load Based GSM and UMTS Handover Enhancement Based on Iur-g

RAN11.1

WRFD-070006*

GSM and UMTS Load Balancing Based on Iur-g

RAN12.0

14

15

16

* These two features use Huawei private protocol.


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Inter-RAT Load Balance Between LTE and UMTS eNodeB

MME

load measurement and evaluation

eNodeB

Cell load Info.

RIM includes cell load status (overload, congestion, normal).

MME SGSN

RNC

SGSN balance Load and reduce call drop & handover failure rate

Load

GU RAN

NodeB

RIM includes GU cell load status (overload, congestion, normal). Perform Inter-RAT MLB

Interoperation: eNodeB and GU RAN Criteria vary based on different vendors policy

LTE Threshold LTE UMTS

OSS introduced to coordinate eNodeB and

UMTS

GBSS&UMTS and further improve GUL network performance

Before

After

15% UL Network Throughput Increase HUAWEI TECHNOLOGIES CO., LTD.

Huawei Confidential

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Load-Based PS Handover/Redirection from UMTS to LTE Description: • In some scenarios, such as after a CSFB call or moving at the edge of LTE coverage, although LTE coverage is available, UE still use UMTS to do PS service. • In case of UMTS load is high, those UEs can be pushed back to LTE cells by PS handover or redirection based on the UE’s capability.

Trigger : • service cell Load_Value > Thresh_Load • Neighbor cell Qual_N>Thresh_Qual, and neighbor load
LTE

Serving Cell

UMTS LDR triggered

Benefits: • Reduces the possibility of UMTS congestion by allowing more UEs in the UMTS to handover/redirection to LTE. • Improves the LTE network resource utilization at the early stage of LTE network deployment.

LTE

Handover/Redirection triggered

Dependency: • Redirection: UE should support 3GPP R8 & UMTS/LTE dual mode. • PS Handover: The UE should support 3GPP R8, UMTS-to-LTE PS handovers & LTE measurements. UMTS/LTE CN should support UMTS to LTE PS handover


Target Cell

Huawei Confidential

UMTS

Page 45

Case：Performance for Load Balance Solution(K Country V Operator) L2U MLB of Operator X in middle east Asia Background：The LTE network is high load as half ratio UE type is dongle and the UE DL throughput is lower in the peak

time. The UMTS network load is not very high and. The load can be balanced between UMTS and LTE network.

LTE1800

L2U coverage based PS HO

LTE1800

L2U Mobility Load Balance F3

UMTS2100

UMTS Intra band HO

UMTS2100

UMTS Inter band LDR F2

UMTS2100

UMTS2100

UMTS2100

F1

UMTS2100

UMTS2100

UMTS2100

UMTS Coverage based HO

On IRAT HO

The L2U Handover success rate is above 99% after on IRAT HO


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1


2


3



Huawei Confidential

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KPI-IRAT PS HO PS HO Statistic Counter ID

Counter Name

Counter Description

1526726986 1526726987 1526726988

L.IRATHO.E2C.PrepAttOut L.IRATHO.E2C.ExecAttOut L.IRATHO.E2C.ExecSuccOut

Number of Outgoing Handover Attempts from E-UTRAN to CDMA2000 Number of Performed Outgoing Handovers from E-UTRAN to CDMA2000 Number of Successful Outgoing Handovers from E-UTRAN to CDMA2000

1526726989 1526726990 1526726991 1526726992 1526726993 1526726994 1526727226 1526727227 1526727228

L.IRATHO.E2W.PrepAttOut L.IRATHO.E2W.ExecAttOut L.IRATHO.E2W.ExecSuccOut L.IRATHO.E2G.PrepAttOut L.IRATHO.E2G.ExecAttOut L.IRATHO.E2G.ExecSuccOut L.IRATHO.E2T.PrepAttOut L.IRATHO.E2T.ExecAttOut L.IRATHO.E2T.ExecSuccOut

Number of Outgoing Handover Attempts from E-UTRAN to UTRAN Number of Performed Outgoing Handovers from E-UTRAN to UTRAN Number of Successful Outgoing Handovers from E-UTRAN to UTRAN Number of Outgoing Handover Attempts from E-UTRAN to GERAN Number of Performed Outgoing Handovers from E-UTRAN to GERAN Number of Successful Outgoing Handovers from E-UTRAN to GERAN Number of Outgoing Handover Attempts from E-UTRAN to TD-SCDMA Number of Performed Outgoing Handovers from E-UTRAN to TD-SCDMA Number of Successful Outgoing Handovers from E-UTRAN to TD-SCDMA

KPI

Formula

LTE->WCDMA LTE->GSM LTE->CDMA2000

L2W Handover Success Rate exec L2G Handover Success Rate exec L2C Handover Success Rate exec

[L.IRATHO.E2W.ExecSuccOut]/[L.IRATHO.E2W.ExecAttOut]*{100} [L.IRATHO.E2G.ExecSuccOut]/[L.IRATHO.E2G.ExecAttOut]*{100} [L.IRATHO.E2C.ExecSuccOut]/[L.IRATHO.E2C.ExecAttOut]*{100}

LTE->TD-SCDMA

L2T Handover Success Rate exec

[L.IRATHO.E2T.ExecSuccOut]/[L.IRATHO.E2T.ExecAttOut]*{100}


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KPI-IRAT PS HO failures IRAT counters for PS HO different failure reasons Counter ID

Counter Name

1526728306

L.IRATHO.E2G.Prep.FailOut.MME

1526728307

L.IRATHO.E2G.Prep.FailOut.NoReply

1526728308

L.IRATHO.E2G.Prep.FailOut.PrepFailure

1526728309

L.IRATHO.E2T.Prep.FailOut.MME

1526728310

L.IRATHO.E2T.Prep.FailOut.NoReply

1526728311

L.IRATHO.E2T.Prep.FailOut.PrepFailure

1526728316

L.IRATHO.E2W.Prep.FailOut.MME

1526728317

L.IRATHO.E2W.Prep.FailOut.PrepFailure

1526728318

L.IRATHO.E2C.Prep.FailOut.NoReply


Counter Description Number of handover prepare failure from LTE to GERAN for MME reason Number of handover prepare failure from LTE to GERAN for no reply with GERAN Number of handover prepare failure from LTE to GERAN for prepare failure indication from GERAN Number of handover prepare failure from LTE to TD-SCDMA for MME reason Number of handover prepare failure from LTE to TD-SCDMA for no reply with TD-SCDMA Number of handover prepare failure from LTE to TD-SCDMA for prepare failure indication from TD-SCDMA Number of handover prepare failure from LTE to WCDMA for MME reason Number of handover prepare failure from LTE to WCDMA for prepare failure indication from WCDMA Number of handover prepare failure from LTE to WCDMA for no reply with WCDMA

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KPI-IRAT redirection & CSFB counters Redirection Counters Counter ID

Counter Name

Counter Description

1526728326

L.RRCRedirection.E2W

Number of Redirction to WCDMA

1526728327

L.RRCRedirection.E2G

Number of Redirction to GERAN

1526728330

L.RRCRedirection.E2W.PrepAtt

Number of attempt Redirction to WCDMA

1526728331

L.RRCRedirection.E2G.PrepAtt

Number of attempt Redirection to GERAN

CSFB Counters Counter ID

Counter Name

Counter Description

1526728321

L.CSFB.PrepAtt

Number of CS fallback indicators received by the eNodeB

1526728323

L.CSFB.E2W

Number of CS fallback procedures to UTRAN

1526728324

L.CSFB.E2G

Number of CS fallback procedures to GERAN

1526728322

L.CSFB.PrepSucc

Number of successful CS fallback responses from the eNodeB


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KPI-MLB Performance 1/2 Level

Counter name

Counter Description

Cell

L.RRCRel.DedicatePri.UMTS.High

Dedicated Priority (UMTS highest) RRC Release Time

Cell

L.IRATHO.E2W.PrepAttOut

Number of Inter-RAT Handover Attempts from E-UTRAN to WCDMA Network

Cell

L.IRATHO.E2W.ExecAttOut

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

Cell

L.IRATHO.E2W.ExecSuccOut

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

Cell

L.Thrp.Time.DL

Transmit duration of downlink PDCP SDUs

Cell

L.ChMeas.PRB.DL.Used.Avg

Average number of used PDSCH PRBs

Cell

L.Thrp.bits.DL

Total downlink traffic volume for PDCP SDUs

Cell

L.HHO.IntereNB.InterFreq.PrepAttOut

Number of inter-eNodeB inter-frequency outgoing handover attempts

Cell

L.HHO.IntereNB.InterFreq.ExecAttOut

Number of inter-eNodeB inter-frequency outgoing handover executions

Cell

L.HHO.IntereNB.InterFreq.ExecSuccOut

Number of inter-eNodeB inter-frequency outgoing handover success


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KPI-MLB Performance 1/2 Level

Counter name

Counter Description

Cell

L.HHO.InterFreq.UeNumLoad.PrepAttOut

Number of user-number-load-based inter-frequency handover preparation attempts

Cell

L.HHO.InterFreq.UeNumLoad.ExecAttOut

Number of user-number-load-based inter-frequency handover executions

Cell

L.HHO.InterFreq.UeNumLoad.ExecSuccOut

Number of successful user-number-load-based inter-frequency handover executions

Cell

L.Traffic.User.Ulsync.Avg

Average number of UL synchronized users in a cell

Cell

L.Thrp.bits.DL

Total downlink traffic volume for PDCP SDUs

Cell

L.Thrp.Time.DL

Transmit duration of downlink PDCP SDUs

Cell

L.InterFreq.UeNumLoad.Dur.Cell

Total duration of inter frequency user high load status

Cell

L.IRATHO.E2W.Load.PrepAttOut

Number of Handover Preparation Attempts from E-UTRAN to WCDMA Network Triggered Because of High Load

Cell

L.IRATHO.E2W.Load.ExecAttOut

Cell

L.IRATHO.E2W.Load.ExecSuccOut

Number of inter-RAT handover execution attempts from E-UTRAN to WCDMA network triggered because of high load Number of successful inter-RAT handover executions from E-UTRAN to WCDMA network triggered because of high load

Cell

L.RRCRedirection.E2W.Load

Cell

L.RRCRel.DedicatedPri.WCDMA.High


Number of redirections from E-UTRAN to WCDMA network triggered because of high load Number of times that the WCDMA network is configured as the highest frequency priority in an IMMCI IE

Huawei Confidential

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DT KPI Recorded and analyzed by Probe/Assistant


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Thank you www.huawei.com Copyright©2009 Huawei Technologies Co., Ltd. All Rights Reserved. The information contained in this document is for reference purpose only, and is subject to change or withdrawal according to specific customer requirements and conditions.

01 GUL Interworking Principal & Solution Introduction V1.1

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