136873757 huawei eran3 0 csfb feature introduction

Huawei eRAN3.0 CSFB Feature Introduction

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Node B Products of Huawei Apr. 2006 HUAWEI TECHNOLOGIES CO., LTD.

Huawei CSFB Feature Roadmap Released

CSFB to UTRAN • PS HO • PS redirection

CSFB to GERAN • PS HO • PS redirection • CCO

Flash CSFB to UTRAN

CSFB to UTRAN with LAI

Adaptive blind CSFB

Flash CSFB to GERAN

CSFB to GERAN with LAI

CSFB Steering CSFB with eMPS

CSFB to GERAN • CCO with NACC

CSFB to CDMA2000 1xRTT

eRAN2.1

eRAN2.2

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eRAN3.0

Huawei Confidential

Next Evolutions

Planned Planning

Chapter One ： Feature Introduction 

Architecture and functionalities



Mobile Originating call



Mobile Terminating call



SMS



Emergency call

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CSFB: brief introduction

Circuit Switched Fallback (CSFB, 3GPP TS23.272) The CS fallback in EPS enables the provisioning of voice and other CS-domain services (e.g. SMS/ LCS) by reuse of CS infrastructure when the UE is served by E‑UTRAN.

 This function is only available in case E‑UTRAN coverage is overlapped by either GERAN coverage or UTRAN coverage.

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CSFB: Architecture and functionalities •Need to be R8 ready •Maintaining SGs association with MME

for the mobility management and paging procedures between EPS and CS domain.

MSC/VLR A

GERAN

Gb

Gs SGSN

Iu-cs

C/D Gr

UTRAN •Multi-mode G/U/L •CSFB capable •Support of procedures: Combined EPS/IMSI Attach, Update, Detach.

HSS/HLR

SGs

Iu-ps S3

S6a

S12 PCRF

S4

MME

•Deriving a VLR number and LAI from the TAI of the current cell, or using a default VLR number and LAI. •Maintaining SGs association with MSC/VLR for EPS/IMSI Attached UE •Triggering paging to eNodeB (when MSC-S pages the UE) •Initiating IMSI Detach at EPS Detach

S11

S5

SGi

S1-U G/U/L handset

E-UTRAN

S-GW •Forwarding paging request for CS domain to the UE. •Directing the UE to the target CS capable cell. (PS HO/redirection with or without SIBs).

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Rx

S7

S1-MME

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Internet / intranet / Operators & 3rd Party Applications

PDN-GW

Page 5

CSFB: Mobile Originating call 7.IAM 6.Initiate voice call

NodeB

MSC-VLR

RNC

HSS/HLR

SGSN SGs

3G

e gna hc met sys- r et nI

LTE

1. Ext Service RQ (CSFB indicator)

S HO 4. P

3.optional measurement eNodeB 5. eNB direct the UE to G/U

n ectio r i d S re or P

MME

r) icato d n i SFB ge (C a s s e AP M 2. S1

SAE-GW

 RAT change (and selection) is under full network control (eNodeB triggers the RAT change towards to 2G/3G based on the UE’s capability\measurement\SPID indication from MME.) HUAWEI TECHNOLOGIES CO., LTD.

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CSFB: Mobile Terminating call 1.IAM

9.Voice call establishment

e gna hc met sys- r et nI

LTE

SGs

or O H PS .

6

2. Paging RQ (Domain indicator: CS) 3. Ext Service RQ (CSFB indicator)

5.measurement

MSC-VLR

SGSN

8.P ag in g

3G

RNC

Re sp on se

NodeB

4.

eNodeB

7. eNB direct the UE to G/U

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PS

M AP 1 S

n tio c ire red

ge sa s e

B SF C (

MME

) t or a ic ind

SAE-GW

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HSS/HLR

CSFB to UMTS (PS HO) MO call

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MT call

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CSFB to UMTS (PS RRC Redirection w/o RIM) MO call (R9: with RIM)

MO call (R8: without RIM)

PS Suspend

PS Suspend

*MT call’s procedure is same.

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CSFB to GERAN (PS HO) MO call

MT call

BSC

In case GERAN or UE can’t support DTM (Dual transfer Mode) the PS service will be suspended

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CSFB to GERAN (PS RRC Redirection w/o RIM) MO call (R9: with RIM)

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MO call (R8: without RIM)

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CSFB to GERAN (CCO w/o RIM) MO call (w/o RIM)

In case GERAN or UE can’t support DTM (Dual transfer Mode) the PS service will be suspended

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CSFB to UTRAN: Three mechanisms

R8 PS Handover: base on the inter-RAT PS handover procedures

R8 PS redirection: RRC release with “redirectedCarrierInfo”IE to UE

R9 PS redirection: RRC release with a carrier frequency and UTRAN cell’s SIBs acquired by RIM procedures before CSFB.

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CSFB to GERAN: Four mechanisms

R8 PS Handover: base on the inter-RAT PS handover procedures

R8 PS redirection: RRC release with “redirectedCarrierInfo”IE to UE R9 PS redirection: RRC release with a carrier frequency list and cell’s SIBs acquired by RIM procedures before CSFB. R8 CCO with NACC: HandoverCommand With target cell and SI

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CSFB: SMS  UE is EPS/IMSI attached and the CS access domain is chosen by the UE and/or the home PLMN for delivering short messages.  SMS support is based on the connectionless SGs reference point between the MME and the MSC Server and use of NAS signalling between the UE and the MME.  The MO SMS and MT SMS are signalled over SGs and do not cause any CS Fallback to GERAN/UTRAN RATs, and consequently does not require any overlapped GERAN/UTRAN coverage.

No CS Fa llba ck is pe rforme d for S MS HUAWEI TECHNOLOGIES CO., LTD.

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CSFB: Emergency call

 E-UTRAN may use the emergency indication for selecting a particular radio access network (2G or 3G) for CS emergency handling.  If PS handover is initiated, E-UTRAN may indicate priority level of the CSFB to the target RAT, in order to prepare radio resource at target RAT in appropriate way, e.g. priority allocation of the RAB resource.

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Chapter Two: CSFB Algorithm at eNB ď ś Triggering phase The eNodeB receives a CS Fallback Indicator from the MME. If the eNodeB supports blind handovers to an inter-RAT system, it performs a blind handover without delivering the measurement configuration to the UE. Otherwise, the eNodeB delivers the measurement configuration to the UE. Compared with measurementbased handovers, blind handovers can reduce the access delay. Therefore, blind handovers take precedence over measurement-based handovers.

Blind handovers, however, have an impact on the handover success rate.

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

The eNodeB delivers



The eNodeB checks

The eNodeB executes

the inter-RAT

the measurement

CSFB to enable the UE

measurement

results and

to initiate the voice call

configuration, and the

generates a list of

in the target cell.

UE performs inter-RAT

candidate cells.

measurements



The ongoin2g PS services of the UE might

accordingly. 



be handed over to the

In abnormal cases, eNB

target cell or suspended

performs blind

in the source cell.

procedure.

Measurement Phase

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Decision Phase

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Execution Handover

eRAN2.0/2.1

R8 CSFB  Blind Scenario ：  

A list of candidate cells is generated on the basis of the blind handover priorities, which are determined by both the RAT-specific priorities and the cell-specific priorities.

The RAT-specific priorities used in blind handovers for CSFB are defined through the InterRatHighestPri, InterRatSecondPri, and InterRatLowestPri parameters.

 Measure Scenario ： 

eNB sends the UE the measurement configuration, according to which the UE performs measurements on the specified system. The measurement configuration sent to the UE contains the configuration information for only the RATs and frequencies that are supported by the UE.



eNB selects the best cell from UE’s measurement report.

B1 entering condition:

Mn + Ofn − Hys > Thresh

Mn is the measurement result of the neighboring cell. Ofn is the frequency-specific offset for the frequency of the neighboring cell. Hys is the hysteresis for event B1. Thresh is the threshold for event B1. The values of Thresh are set on the basis of the measurement quantities of each RAT. The Received Signal Code Power (RSCP) threshold for CSFB to UTRAN, Ec/No threshold for CSFB to UTRAN, threshold for CSFB to GERAN, and threshold for CSFB to CDMA2000 1xRTT are specified through the CsfbHoUtranB1ThdRSCP, CsfbHoUtranB1ThdECN0, CsfbHoGeranB1Thd, and CsfbHoCDMAB1ThdPS parameters respectively.

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eRAN2.2

Flash CSFB ( R9 redirection with SIBs ） GSM/UMTS Core

RIM : RAN information exchanging

LTE Core

Ke y P oint:

SGSN

RAN information

BSC/RNC

RAN information request

1.

MME

eNB request system information from BSC/RNC when establish Inter-RAT neighbor relation;

Frequency and target cell system information

2.

BSC/RNC reply system information. If system information update ， BSS/RNC notify eNodeB and send the latest information;

3.

Core Network doesn’t handle the message, only forward;

4.

2G/3G Access

LTE Access

Flash CSFB:

•

Saving 1s for UMTS compare with R8 CSFB

•

Saving 2s for GSM compare with R8 CSFB

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eNB doesn’t translate message from BSC/RNC ， send to UE directly;

5.

eNB fill out the target frequency and related neighbor cell information in RRC_Release message.

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eRAN3.0

CSFB to UTRAN/GERAN with LAI LTE Core

Step1: eNB receives “Registered LAI” from MME MME sends “Registered LAI” to eNB via “Initial Context Setup Request” or “UE Context Modification Request” message.

TA1/LA1

MME

GUL

TAI/L AI

CSFB to LA1

Select same LA to CSFB

GUL

TA3/LA1

TA2/LA2

GUL

LAI Based CSFB:

1. Priority to select target GU cells with same LAC as UE registered in GU NW during CSFB to avoid LAU (0.5s~3s).

2. Support National Roaming Ue to select suitable fallback RAT/Cell bases on LAI

Step2: eNB selects target network with LAI consideration 1> Blind case: following the priority below.

1>Neighboring cell with the same LAI with “Registered LAI”; 2>Neighboring cell with the same PLMN with “registered LAI”; 3>Neighboring cell with the same PLMN with the UE current serving PLMN. 2>Measurement case: 1>if any of the neighboring frequency’s cell PLMN is the same with “Registered LAI”, or if any of the neighboring frequency’s cell PLMN is the same with the UE current serving PLMN, and the UE supports the RAT and the frequency, eNB will send these frequency to UE for measuring.

2>eNB will choose the same LAI from the measurement reports.

Indicator among multi-PLMNs. HUAWEI TECHNOLOGIES CO., LTD.

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CSFB key parameters MO Parameter ID CSFallBackBlindHoCfg InterRatHighestPri

CSFallBackBlindHoCfg UtranLcsCap

Description Indicates the high-priority system to be considered in blind handovers for CS fallback. It is UTRAN by default.

Indicates the medium-priority system to be considered in blind handovers for CS fallback. It is GERAN by default. If this parameter is set to null, the system with the medium blind handover priority is not specified. In this case, only the blind handovers to the high-priority system are applicable.

Indicates the low-priority system to be considered in blind handovers for CS fallback.

It is CDMA2000 by default. If this parameter is set to null, the system with the low blind handover priority is not specified. In this case, only the blind handovers to the high- and medium-priority systems are applicable.

Indicates the Location Services (LCS) capability of the UTRAN.

CSFallBackBlindHoCfg GeranLcsCap

Indicates the Location Services (LCS) capability of the GERAN.

CSFallBackBlindHoCfg CdmaLcsCap

Indicates the Location Services (LCS) capability of the CDMA2000.

CSFallBackHo

CsfbHoUtranTimeToTrig

CSFallBackHo

CsfbHoGeranTimeToTrig

Indicates the time-to-trigger for event B1 that is used in CS fallback to UTRAN/GERAN/CDMA2000. When CS fallback to UTRAN/GERAN/CDMA2000 is applicable, this parameter is set for UEs and used in the evaluation of whether to trigger event B1. When detecting that the signal quality in at least one UTRAN/GERAN/CDMA2000 cell meets the entering condition, the UE does not send a measurement report to the eNodeB immediately. Instead, the UE sends a report only when the signal quality continuously meets the entering condition during the time-to-trigger. This parameter helps decrease the number of occasionally triggered event reports, the average number of handovers, and the number of wrong handovers, and thus helps prevent unnecessary handovers. For details, see 3GPP TS 36.331.

CSFallBackHo

CsfbHoCDMATimeToTrig

CSFallBackBlindHoCfg InterRatSecondPri

CSFallBackBlindHoCfg InterRatLowestPri

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MO CSFallBackHo

Parameter ID Description CsfbHoUtranB1ThdRSCP Indicates the RSCP threshold for event B1, which is used in CS fallback to UTRAN. When CS fallback to UTRAN is applicable, this parameter is set for UEs and used in the evaluation about whether to trigger event B1. This parameter indicates the RSCP requirement for the UTRAN cells to be included in the measurement report.

A UE sends a measurement report related to event B1 to the eNodeB when the RSCP in at least one UTRAN cell exceeds this threshold and other triggering conditions are met. For details, see 3GPP TS 36.331.

CSFallBackHo

CsfbHoUtranB1ThdECN0

Indicates the Ec/No threshold for event B1, which is used in CS fallback to UTRAN. When CS fallback to UTRAN is applicable, this parameter is set for UEs and used in the evaluation about whether to trigger event B1. This parameter indicates the Ec/No requirement for the UTRAN cells to be included in the measurement report.

A UE sends a measurement report related to event B1 to the eNodeB when the Ec/No in at least one UTRAN cell exceeds this threshold and other triggering conditions are met. For a cell with large signal fading variance, set this parameter to a large value to prevent unnecessary handovers. For a cell with small signal fading variance, set this parameter to a small value to ensure that the handover is performed in time. For details, see 3GPP TS 36.331.

CSFallBackHo

CsfbHoGeranB1Thd

Indicates the RSSI threshold for event B1 that is used in CS fallback to GERAN. A UE sends a measurement report related to event B1 to the eNodeB when the RSSI in at least one GERAN cell exceeds this threshold and other triggering conditions are met. For details, see 3GPP TS 36.331.

CSFallBackHo

CsfbHoCDMAB1ThdPS

Indicates the pilot strength threshold related to event B1, which is used in CS fallback to CDMA2000. A UE sends a measurement report related to event B1 to the eNodeB when the pilot strength in at least one CDMA2000 cell exceeds this threshold and other triggering conditions are met. For details, see 3GPP TS 36.331.

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MO Parameter ID Default Value CSFallBackBlindHoCf InterRatHighestPri UTRAN UTRAN, GERAN, g CDMA2000

Actual UTRAN, GERAN, CDMA2000

Unit None

CSFallBackBlindHoCf InterRatSecondPri GERAN g

UTRAN, GERAN, CDMA2000, NULL

UTRAN, GERAN, CDMA2000, NULL

None

CSFallBackBlindHoCf InterRatLowestPri CDMA2000 g

UTRAN, GERAN, CDMA2000, NULL

UTRAN, GERAN, CDMA2000, NULL

None

CSFallBackBlindHoCf UtranLcsCap g

OFF(Off)

OFF(Off), ON(On)

OFF, ON

None

CSFallBackBlindHoCf GeranLcsCap g

OFF(Off)

OFF(Off), ON(On)

OFF, ON

None

CSFallBackBlindHoCf CdmaLcsCap g

OFF(Off)

OFF(Off), ON(On)

OFF, ON

None

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MML Command MOD CSFALLBACKBLINDHOCF G LST CSFALLBACKBLINDHOCF G MOD CSFALLBACKBLINDHOCF G LST CSFALLBACKBLINDHOCF G MOD CSFALLBACKBLINDHOCF G LST CSFALLBACKBLINDHOCF G MOD CSFALLBACKBLINDHOCF G LST CSFALLBACKBLINDHOCF G MOD CSFALLBACKBLINDHOCF G LST CSFALLBACKBLINDHOCF G MOD CSFALLBACKBLINDHOCF G LST CSFALLBACKBLINDHOCF G

MO

Parameter ID

Default Value

CSFallBackHo

CsfbHoUtranTim 40ms eToTrig

CSFallBackHo

CsfbHoGeranTi 40ms meToTrig

CSFallBackHo

CsfbHoCDMATi 40ms meToTrig

CSFallBackHo

CsfbHoUtranB1T -106 hdRSCP

CSFallBackHo

Actual 0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 512ms, 480ms, 640ms, 1024ms, 1280ms, 2560ms, 5120ms

Unit

MML Command

0ms, 40ms, 64ms, ms 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, ms 512ms, 480ms, 640ms, 1024ms, 1280ms, 2560ms, 5120ms ms

MOD CSFALLBACKHO LST CSFALLBACKHO

-120~-25

-120~-25

dBm

MOD CSFALLBACKHO LST CSFALLBACKHO

CsfbHoUtranB1T -13 hdECN0

-48~0

-24~0

0.5dB

MOD CSFALLBACKHO LST CSFALLBACKHO

CSFallBackHo

CsfbHoGeranB1 -103 Thd

-110~-48

-110~-48

dBm

MOD CSFALLBACKHO LST CSFALLBACKHO

CSFallBackHo

CsfbHoCDMAB1 -34 ThdPS

-63~0

-31.5~0

0.5dB

MOD CSFALLBACKHO LST CSFALLBACKHO

MOD CSFALLBACKHO LST CSFALLBACKHO MOD CSFALLBACKHO LST CSFALLBACKHO

Switches are not shown here. Please refer to CSFB FPD.

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Chapter Three: Algorithm Relationship  LOFD-001033 CS Fallback to UTRAN depends on LOFD-001019 PS Inter-RAT Mobility between E-UTRAN and UTRAN.  LOFD-001034 CS Fallback to GERAN depends on LOFD-001020 PS Inter-RAT Mobility between E-UTRAN and GERAN.  LOFD-001035 CS Fallback to CDMA2000 1xRTT depends on LOFD-001021 PS Inter-RAT Mobility between E-UTRAN and CDMA2000.  LOFD-001052 Flash CS Fallback to UTRAN depends on LOFD-001033 CS Fallback to UTRAN.  LOFD-001053 Flash CS Fallback to GERAN depends on LOFD-001034 CS Fallback to GERAN.  LOFD-001068 CS Fallback with LAI to UTRAN depends on LOFD-001033 CS Fallback to UTRAN.  LOFD-001069 CS Fallback with LAI to GERAN depends on LOFD-001034 CS Fallback to GERAN.

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Chapter Four: Use Case  Deployment Scenario  No IMS support in LTE/SAE or roaming.  E‑UTRAN coverage is overlapped by either GERAN coverage or UTRAN coverage.

G/U coverage

UL dual mode UE

Camping (LTE)

Voice (G/U)

 PLMN selection indicator in SIM card  Frequency priority in network system information broadcast

 CSFB to G/U to make the CS call

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LTE coverage

Back to LTE Idle UE:  Frequency priority in G/U system information broadcast Active UE:  PS redirection  PS HO based on service

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Thank You

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