LTE_WCDMA IRAT Saudi Team Tutorial 10-01-2012

LTE/UMTS IRAT Features Tutorial

Xingkai Bao

Alcatel-Lucent

10/01/2012

All Rights Reserved Alcatel-Lucent 2006, #####

LTE/WCDMA IRAT Features Overview

LTE to WCDMA mobility LTE to WCDMA blind redirection: ready in LA2, LA3, LA4 LTE to WCDMA blind enhanced redirection: ready in LA4 and beyond LTE to WCDMA idle reselection: Ready in LA2, LA3, LA4 LTE to WCDMA PSHO: Ready in LA3, LA4, LA5 and beyond

WCDMA to LTE mobility WCDMA to LTE idle Reselection: ready in LA2 LA3 LA4 and beyond WCDMA to LTE redirection: Under development WCDMA to LTE PSHO: Under development

Voice calls in LTE network Circuit switched voice call fall back (CSFB) via redirection: Ready in LA3 CSFB via enhanced redirection: Ready in LA4 (ALU SGSN not ready) CSFB via PSHO: ready in LA3 and beyond Single radio voice call continuity (SRVCC): droped from LA5 to LA6 Enhanced SRVCC (eSRVCC): planned in LA6


UTRAN

NBNBNB RNCRNCRNCIuB

LTE/WCDMA IRAT Network Diagram in Deployment Phase 1

PCRFPCRFE-UTRAN

SGWSGWeNBeNB

MMEMME

PGW / GGSN PGW / GGSN

S11

S1-u S5/S8

LTE HSS WCDMA HLR

LTE HSS WCDMA HLR

S1-mme

SGSNSGSNSGSN

S10

UE

Gx

SS7

Internet / Servers

SGi/Gi

Gn-data

Iu-PS

S6a

Gn-signaling


LTEWCDMA IRAT Mobility Features in Deployment Phase 1

LTE to WCDMA reselection LTE in idle mode. LTEs RRC connection is released when it becomes idle already Routing area update procedure

LTE to WCDMA redirection LTE RRC connection is released, and WCDMA bearers are re-established Large PS data interruption time, and data is lost LE5.0 data interruption time: 3.2-5.0sec, Avg: 3.4sec

WCDMA to LTE reselection Idle mobility from WCDMA to LTE WCDMA RRC stays in PCH for 10 second, and LTE RSRP>-104dBm LE5.0 reselection time(From UE makes decision to TAU complete): 8-10 sec Avg:

8.9sec


LTE -> WCDMA/GSM Cell Reselection/Routing Area Update (Ref: 23.401 V8.15.0)

Alcatel - Lucent Proprietary

MS eNodeB New SGSN Old MME SGW Old SGSN PGW HSSUE reselects from LTE to UTRAN

or GERAN

(M1) Routing Area Update Request:

(M2) SGSN Context Request:

(M3) SGSN Context Response:

ME1: Security Functions

(M4) SGSN Context Acknowledge:

(M5) Update PDP Context Request:

(M6) Update PDP Context Response:

(M7) Update Location:

(M8) Cancel Location:

(M9) Cancel Location Ack:

(M10) Insert Subscriber Data:

(M11) Insert Subscriber Data Ack:

(M12) Update Location Ack:

(M13) Routing Area Update Accept:

(M14) Routing Area Update Complete:

(M15) Delete Session Request:

(M16) Delete Session Response:

ME2: S1-AP S1 Release:


LTE to WCDMA Redirection(FTS for FRS84807, 5.1.2.3)

UE eNodeB MME SGW SGSN GERAN UTRAN PGW

Alcatel Lucent Proprietary

ME1: Uplink and Downlink User Plane

UE sends event A2_blind when radio conditions in service cell are very bad. Threshold for A2_blind is lower than threshold for A2_MG

(M1) RRC-MeasurementReport (event A2_blind)

eNodeB decides to redirect the UE to GERAN/UTRAN carrier without measurements on target cell

(M2) RRC-ConnectionRelease (cause=other, redirectedCarrierInfo, optional IdleModeMobilityControlInfo)

(M3) S1-AP-UE Context Release Request (cause=Inter-RAT redirection)

S1 connection released by MME and S1-U bearers removed in SGW

(M4) S1-AP-UE Context Release Command

(M5) S1-AP-UE Context Release Complete

ME2: Cell Selection

ME3: Routing Area Update

ME4: Uplink and Downlink User Plane


WCDMA-> LTE Cell Reselection/Tracking Area Update (TS 23.401 v 8.15.0)

Alcatel Lucent Proprietary

UE eNodeB RNC BSC old MME MME SGSN SGW PGW PCRF HSSTrigger to start TAU Procedure

(M1) Tracking Area Update Request

(M2) Tracking Area Update Request

(M3) SGSN Context Request

(M4) SGSN Context Response

ME1: Security procedures

(M5) Context Acknowledge

(M6) Create Session Request

(M7) Modify Bearer Request

(M8) PCEF Initiated CC Request IP-CAN Session Establishment

(M9) CC Answer IP-CAN Session Establishment

(M10) Modify Bearer Response

(M11) Create Session Response

(M12) Update Location Request

(M13) Cancel Location

(M14) Cancel Location Acknowledge

(M15) Cancel Location

(M16) Iu Release Command

(M17) Iu Release Complete

(M18) Cancel Location Acknowledge

(M19) Update Location Acknowledge

(M20) Tracking Area Update Accept

(M21) Tracking Area Update Complete


UTRAN

NBNBNB RNCRNCRNCIuB

LTE/WCDMA IRAT Network Diagram in Deployment Phase 2

PCRFPCRFE-UTRAN

SGWSGWeNBeNB

MMEMME


S11

S1-u S5/S8

LTE HSS WCDMA HLR

LTE HSS WCDMA HLR

S1-mme

SGSNSGSNSGSN

S10

UE

Gx

SS7

Internet / Servers

SGi/Gi

Gn-data

Iu-PS

S6a

Gn-signaling

UMTSMSC

UMTSUMTSMSCMSC

Iu-CSCircuitVoice

Network

SGs

SS7



LTE to WCDMA Circuit Switched Call Fall Back (CSFB) through redirection Mobile Originated CSFB

UE initiates a voice call, UE fall back to 3G WCDMA for both PS data and CS call

PS data interruption time: 3-5 seconds CS call setup time: about 4-5 seconds

Mobile Terminated CSFB Network initiates a voice call, UE fall back to 3G WCDMA for both PS data

and CS call PS data interruption time: 3-5 seconds CS call setup time: about 4-5 seconds

Idle CSFBs LTE is idle mode, MO or MT, the UE fall back to 3G WCDMA with CS call RRC connection is firstly established RRC connection is then released Reestablish the LTE RRC waits about 200 ms



CSFB through enhanced redirection (eCSFB) The enhancement is on the UTRAN container on each LTE sectors UTRAN neighbor All UMTSs MIB and SIB information are sent to UMTS in the LTE RRC connection release. The UE

does not need to wait for MIB and SIB information after it connects to WCDMA

MIB: Master Information Block SIB1: The system information block type 1 contains NAS system information as

well as UE timers and counters to be used in idle mode and in connected mode.

SIB3: The system information block type 3 contains parameters for cellselection and re-selection.

SIB5: The system information block type 5 contains parameters for theconfiguration of the common physical channels in the cell.

SIB7: The system information block type 7 contains the fast changingparameters UL interference and Dynamic persistence level

CS call setup time is 0.5 seconds shorter

PS data interruption time is 0.3 seconds shorter


Mobile Originating CSFB using Redirection

UE/MS MME BSS/RNS MSC eNodeB

2. Optional Measurement Report Solicitation

9. CS MO call

10b. Location Area Update

10a. Service Reject In case MSC is changed

10c. CS MO call

6. LA Update or Combined RA/LA Update or RA Update or LA Update and RA Update

3a. NACC,

5. S1 UE Context Release

1a. Extended Service Request

S-GW

4. S1-AP: S1 UE Context Release Request

1b. S1-AP message with CS Fallback indicator

7a. Suspend (see 23.060)

8. Update bearer(s)

SGSN

7b. Suspend Request / Response

11. Routing Area Update or Combined RA/LA Update

3b. RRC connection release

eNB initiated handover based on CSFB Indication

Release with Redirection

RRC Connection and SGSN Relocation Procedures

Circuit Call Request

Source: 3GPP TS 23.272


Mobile Terminating CSFB using Redirection

9a. Connection Reject

1a. CS Paging Notification 1a. Paging Request

If the MSC is changed

SGSN

10. CS Call Establishment procedure

6. LA Update or Combined RA/LA Update or RA Update or LA Update and RA Update

5. S1 UE Context Release

BSS/RNS

4. S1-AP: S1 UE Context Release Request

1a. Service Request

UE/MS MME MSC

3a. NACC, 3b. Signalling connection release

eNodeB

2. Optional Measurement Report

9. Paging Response

9b. Location Area Update or Combined RA/LA Update

9a. Signalling Connection Release

S-GW

1b. Extended Service Request

1d. S1-AP message with CS Fallback indicator

1c. CS Paging Reject

7a. Suspend (see TS 23.060)

8. Update bearer(s) 7b. Suspend Request / Response

Page request is sent to MME

Service request from UE after user answers the terminating call with CSFB indication.

Redirection, mobile retunes to 3G. RAB are established in 3G

Page response in 3G. Circuit call is established.



Mobile Terminating Call In Idle Mode

1. IAM

3. IAM 4. Paging Request

5. Paging 6. Paging

8a. PS handover 8b. CCO/NACC or RRC Connection Release

8d. Paging Response

9a. Establish CS connection

2. SRI procedure in TS 23.018

G-MSC eNodeB RNC/BSCUE MME HSS MSCVLR

Location Area Update and Roaming Retry for CS Fallback (clause 7.5)

9b. Signalling Connection Release Option 2: MSC is changed

Option 1: MSC is not changed

9b. Connection Reject

8d. Paging Response

8c. Location Area Update

7a. Extended Service Request

7b. Initial UE Context Setup

7a. Service Request

Mobile termination request delivered to MSC

Page request is sent to MME

Service request from UE after user answers the terminating call with CSFB indication.

PS HO or redirection, mobile retunes to 3G.

Page response in 3G. Circuit call is established.



UTRAN

NBNBNB RNCRNCRNCIuB

LTEWCDMA IRAT Network Diagram in Deployment Phase 3

PCRFPCRF

E-UTRAN

SGWSGWeNBeNB

MMEMME


S11

S1-u S5/S8

LTE HSS WCDMA HLR

LTE HSS WCDMA HLR

S1-mme

SGSNSGSNSGSN

S10

UE

Gx

SS7

Internet / Servers

SGi/Gi

Gn-data

Iu-PS

S6a

S3

UMTSMSC

UMTSUMTSMSCMSC

Iu-CSCircuitVoice

Network

SGs

SS7

Direct Utran tunnel

S12

S4



New features supported LTE to WCDMA PS Handover (PSHO) LTE to WCDMA CSFB through PSHO

Interface change Gn-c link S3 link between LTE MME and UMTS SGSN Gn-d link should be only used by GGSN, not for data forwarding New S12 link between LTE SGW and UMTS RNC New S4 link between LTE SGW and UMTS SGSN


LTE to WCDMA PS Handover (PSHO) Introduction

PSHO has much less data interruption time than redirection Redirection: 3-7 seconds PSHO:470-700 milliseconds

PSHO has two Phases Preparation phase

Setup bearer and context in WCDMA Setup the data forwarding tunnel between eNodeB and RNC

Execution phase Mobility from eUtran to Utran Data is forwarded from eNodeB to RNC


LTE to WCDMA PS Handover (PSHO) Introduction

Data forwarding from eNodeB to RNC No data is lost during the PS handover Direct data forwarding Indirect data forwarding with indirect tunnel Indirect data forwarding with direct tunnel

PSHO without data forwarding

Data will be lost during PS handover Longer data interruption time: about 650 milliseconds

CSFB through PSHO

PS data handover to WCDMA much faster CS call setup time is faster by 0.4 to 0.5 seconds due to UtranContainer is sent to UE

before handover execution


Call Follow for the Preparation Phase


Call Follow for the Execution Phase


RF trigger Mechanism in PSHO Blind PSHO

Trigger event: A1_belowServingFloor This feature is in 3GPP but not supported in real products

PS Handover with Measurement Gap

Trigger event 1: A2_enterCoverageAlarm After UE sends the measurement report to eNodeB, eNodeB configs the UE to enter

measurement gap mode. The UE then measures the signal strength of both LTE and WCDMA back and forth

Trigger event 2: B2_mobilityToUtran After the UE sends the measurement report to eNodeB, eNodeB sends the handover_required

message to MME to indicate the handover preparation start

Trigger event 3: A1_leaveingCoverageAlarm If the UE is in measurement gap mode, but the LTEs RSRP becomes stronger than the

A1_leaveingCoverageAlarm thresholds, the eNB indicates the UE to exit measurement gap mode


Data Forwarding Mechanism in LTE to WCDMA PSHO Data forwarding

No data loss during PSHO Reduce the data interruption time during PSHO: 470-480ms in lab

Direct data forwarding from eNB to RNC

eNodeBRNC The fastest way to conduct PSHO: 470-480ms in lab

Indirect data forwarding from eNB to RNC

Through indirect tunnel eNBSGWPGWGGSNSGSNRNC

Through direct S3/S4 tunnel S4 tunnel is between SGW and SGSN eNBSGWSGSNRNC

Through direct S12 tunnel S12 link is between SGW and RNC eNodeBSGWRNC

No Data Forwarding

Data is lost during PSHO Data interruption time is increased to 680ms in lab


CSFB through PSHO Introduction

The data mobility is through PSHO but not redirection when CSFB happens

Much shorter data interruption time 470-500ms compared to 3-5 seconds

No data is lost during lost Higher successful rate due to measurement gap B1 measurement gap is configured for CSFB through PSHO

Only measure WCDMA signal strength Different from the B2 event which needs both LTE and WCDMA

measurement

Much shorter CS call setup time B1 measurement gap increase the RF trigger by 100ms Attaching WCDMA RRC is much faster which saves 2.6 seconds


UTRAN

NBNBNB RNCRNCRNCIuB


PCRFPCRF

E-UTRAN

SGW/PGWSGW/PGWeNBeNB

WMMWMM

S11

S1-u

SDM SDM

S1-mme

UE

Gx

Iu-PS

S6a

MSCMGWMSCMSCMGWMGW

Iu-CS

CircuitVoice

Network

Sv

SS7

Direct Utran tunnel

S4

MGCF

TASSCC ASMGC-8

SCG CTS

ICS

MRF

IMS

Gm

ISCISC

P-CSCF

IBC4

MGW

Rx



Single Radio Voice Call Continuity (SRVCC)

Designed for VoIP in LTE (VoLTE)s mobility to 3G Triggered by RF condition: LTEs signal strength is too weak VoLTE call moves to 3G (WCDMA) CS call When LTEs RF signal strength becomes strong again Voice call stays in 3G (WCDMA)

Anchored the call in IMS SCC AS (5420 SCG) SCC AS manages the leg switching between LTE and UMTS SCC AS for a subscriber is always set in his home PLMN


UTRAN

NBNBNB RNCRNCRNCIuB


PCRFPCRF

E-UTRAN

SGW/PGWSGW/PGWeNBeNB

WMMWMM

S11

S1-u

SDM SDM

S1-mme

UE

Gx

Iu-PS

S6a

MSCMGWMSCMSCMGWMGW

Iu-CS

CircuitVoice

Network

Sv

SS7

Direct Utran tunnel

S4

MGCF

TASSCC ASMGC-8

SCG CTS

ICS

MRF

IMS

Gm

ISCISC

P-CSCFATCFATGW

IBC4

MGW

Rx



New network elements added

ATCF ATGWNew feature: enhanced SRVCC (eSRVCC)

Working scenario is similar to SRVCC but more efficient Moving the anchor for the call to the visited IMS network Anchor no longer in the SCC AS in the subscribers home network Reducing the media latency significantly Need new SDM support


Thank you!

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LTE_WCDMA IRAT Saudi Team Tutorial 10-01-2012

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