11_CSFB call flow_II.....................

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1. CSFB CALL FLOW

2. CS Fallback will be the option for single radio UEs to provide CS services until VoIP is available and implemented. CS Fallback requires the UE to fallback from E-UTRAN and rather uses either GSM or WCDMA if it must connect to the CS domain. The CS Fallback function is of course only possible to realize in areas where E-UTRAN coverage is overlapped with GSM and WCDMA coverage. When CSFB is triggered, LTE terminal will be released from the LTE network and attach to the neighboring GSM or WCDMA network with minimal disruption for the end user. CSFB Basic knowledge

3. CS Fallback decision is only based on information stored in the eNB and the cababilities of the terminal. No measurements will be performed to determine what IRAT cells the terminal can hear. The eNB will select the highest priority frequency relation that is supported by the terminal and perform a blind Release with Redirect to that frequency. The eNB makes the frequency selection based on the following criteria: 1, Terminal capabilities. 2, csFallbackPrio value of each available frequency relation CSFB Basic knowledge

4. RNC Feature ： Feature 1: CS Voice Fallback from LTE //Feature name, on RNC, release in W11.0 CsFallbackLte // Moshell name Feature 2: Release with redirect to LTE //Feature name, on RNC, release in W12.1 ReleaseRedirectLte // Moshell name This feature is an inter-RAT mobility function that provides basic mobility for an LTE-capable UE from WCDMA to LTE Feature 3: LTE Cell Reselection //Feature name, on RNC, release in W11.0 LteCellReselection // Moshell name CSFB CONFIGURATION

5. EnodeB Feature ： Feature 1: CS Fallback to GERAN and UTRAN //Feature name, on eNodeB CsfbToGeranUtran // Moshell name This feature supports the UE to release from the LTE network and attach to the neighboring GERAN or UTRAN with minimal disruption for the end user. This feature requires at least one of the following RAN features to be active: 1.Coverage-Triggered GERAN Session Continuity 2.Coverage-Triggered WCDMA Session Continuity Feature 2: Coverage-Triggered WCDMA Session Continuity //Feature name, on eNodeB WcdmaSessionContinuity // Moshell name This feature prerequisite for CS fallback to UTRAN FDD CSFB CONFIGURATION

6. Activate CS Fallback on RNC: 1.Create EutraNetwork // EutraNetwork : 代表 LTE network cr RncFunction =1,EutraNetwork=1 2.Create EutranFrequency // EutranFrequency : LTE 侧使用的频点 cr RncFunction =1,EutraNetwork=1,EutranFrequency=450 450 # earfcnDl //LTE 侧指定 cell 的 earfcnDl 3.Create EutranFreqRelation // 代表 W cell 和 LTE frequency 的临区 . cr RncFunction =1,UtranCell=YORBS36W1_13,EutranFreqRelation=450 EutraNetwork =1,EutranFrequency=450 CSFB CONFIGURATION

7. Activate CS Fallback on LTE ： 1.Create UtraNetwork // UtraNetwork : W network cr ENodeBFunction =1,UtraNetwork=1 2.Create UtranFrequency // UtranFrequency : W network cr ENodeBFunction =1,UtraNetwork=1,UtranFrequency=10812 10812 # arfcnValueUtranDl // Wcell uarfcnDl 3.Create ExternalUtranCellFDD // ExternalUtranCellFDD ： W Cell cr ENodeBFunction =1,UtraNetwork=1,UtranFrequency=10812,ExternalUtranCellFDD=YORBS36W1_13 371 # physicalCellIdentity //RNC cell primaryScramblingCode rncId =116,cId=3801 # cellIdentity // RNC rncid cell cid mcc=440,mnc=20,mncLength=2 # plmnIdentity // RNC PLMN CSFB CONFIGURATION

8. Activate CS Fallback on LTE ： 4.Create UtranFreqRelation // L cell W frequency cr ENodeBFunction =1,EUtranCellFDD=44020-200014-1,UtranFreqRelation=10812 UtraNetwork =1,UtranFrequency=10812 # utranFrequencyRef 6 # cellReselectionPriority //cell reselection 5.Create UtranCellRelation //L cell W cell . cr ENodeBFunction =1,EUtranCellFDD=44020-200014-1,UtranFreqRelation=10812,UtranCellRelation=YORBS36W1_13 UtraNetwork =1,UtranFrequency=10812,ExternalUtranCellFDD=YORBS36W1_13 # externalUtranCellFDDRef CSFB CONFIGURATION

9. Note: After created relation on ENB and RNC, raise a request to EPC guy for adding mapping info between TAC and LAC on MME . (Important) CSFB CONFIGURATION

10. CSFB Call flow

11. CSFB Signaling flow CSFB BY RRC CONNECTION RELEASE WITH REDIRECT TO UTRAN MO CALL, 3GPP 23.272

12. CSFB Signaling flow CSFB BY RRC CONNECTION RELEASE WITH REDIRECT TO UTRAN MT CALL, 3GPP 23.272