Tuesday 1 November 2016

CSFB Call Flow( in LTE)

CSFB to UMTS network while UE was in idle mode and receive Paging for MT CALL.
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UE <=========================================================> eNodeB
–>Paging for MT Call.
FREQUENCY_SCAN_IND
PAGING_IND CS paging, identity:S-TMSI, reason:MT_CALL
PAGING_IND pagingReason: MT_CALL
–>Extended Service request for MT CS fall back
EXTENDED_SERVICE_REQUEST_AIRMSG
earfcn/pci:39000/167(B40), rsrp: -84.5, rsrq:-10.50, snr:7.00;
rb:0; UL_CCCH: rrcConnectionRequest, cause:mt_Access
rb:0; DL_CCCH: rrcConnectionSetup, txMode:tm2, ttiBundling:no, ulHarqProcesses:5
rb:33; UL_DCCH: rrcConnectionSetupComplete; NAS:Extended service request
rb:33; UL_DCCH: ueCapabilityInformation
rb:33; DL_DCCH: securityModeCommand, cipheringAlgorithm eea2, integrityProtAlgorithm eia2
rb:33; UL_DCCH: securityModeComplete
rb:33; DL_DCCH: rrcConnectionReconfiguration; srb:2; drb:1
rb:33; UL_DCCH: rrcConnectionReconfigurationComplete
rb:33; DL_DCCH: rrcConnectionReconfiguration; measConfig EUTRA
rb:33; UL_DCCH: rrcConnectionReconfigurationComplete
–>redir. to UMTS, uarfcn:10833, psc:370
rb:33; DL_DCCH: rrcConnectionRelease, cause:other(redir. to UMTS, uarfcn:10833, psc:370)
–>UE tunes to UMTS network and read SIB information ( specially SIB19)
MasterInformationBlock
SysInfoType1
SysInfoType5
SysInfoType19
LTE –> UMTS
UARFCN=10833; Rscp=-115
0_URRC_STATE_REPORT_IND
camped on UMTS 404/45(INA/AirTel); LAC=34253; RAC=0; cell_id=27898773; Band=UMTS_BAND_I
NAS RR: Paging Response
UMTS: IDLE_CCCH
–> MT Call/PS call is established in UMTS network.
uarfcn:10833, psc:486, crc:ok, BCCH_BCH_Message
RB0: UL_CCCH: rrcConnectionRequest cause:terminatingConversationalCall
RB0: DL_CCCH: rrcConnectionSetup, RB:1,2,3,4 SRNCI:1A90h SRNTI:020950h
RB2: UL_DCCH: rrcConnectionSetupComplete
RB3: UL_DCCH: initialDirectTransfer(CS domain), NAS RR:Paging Response
CS connection established over new RRC connection
RB3: UL_DCCH: initialDirectTransfer(PS domain), NAS GMM:Routing Area Update Request
RB3: DL_DCCH: downlinkDirectTransfer, NAS MM:Authentication Request
RB3: UL_DCCH: uplinkDirectTransfer, NAS MM:Authentication Response
RB2: DL_DCCH: securityModeCommand(PS domain)
RB2: UL_DCCH: securityModeComplete
RB3: DL_DCCH: downlinkDirectTransfer, NAS GMM:Identity Request
RB3: DL_DCCH: downlinkDirectTransfer, NAS GMM:Routing Area Update Accept
NAS GMM: Routing Area Update Accept, identity:TMSI, T3312:9
NAS GMM: Routing Area Update Complete
RB3: DL_DCCH: downlinkDirectTransfer, NAS CallSS:Connect Acknowledge
NAS CallSS: Setup (mobile terminated call establishment)
NAS CallSS: Call Confirmed
RB2: DL_DCCH: radioBearerSetup RB:5,6,7 state:cell_DCH psc: (DC_Off) (CPC_Off) NB AMR:12.2,
RB2: UL_DCCH: radioBearerSetupComplete
NAS CallSS: Alerting (mobile station to NETWORK direction)
–> Call is disconnected and UE comes in UMTS: IDLE
NAS CallSS: Disconnect (network to mobile station direction), cause:Normal call clearing
NAS CallSS: Release (mobile station direction to network), cause:Normal call clearing
NAS CallSS: Release Complete (network to mobile station direction), cause:Normal call clearing
RB1: DL_DCCH: rrcConnectionRelease cause:normalEvent
RB1: UL_DCCH: rrcConnectionReleaseComplete
UMTS: IDLE
–> UE read SIB 19, UE tunes to LTE network by COMBINED_TA_LA_UPDATING if LTE is preferred n/w
earfcn:39000 (TDD Band 40), pci:167, status:OK, num PRBs:100
earfcn:39000 (TDD Band 40), pci:167, status:OK, num PRBs:100
BCCH_DL_SCH: SIB1, plmn:404/45(INA/AirTel), TDD config:SA2 D s U D D D s U D D, followingSibs:3,6
UMTS –> LTE
UMTS: INACTIVE
camped on LTE 404/45(INA/AirTel); TAC=1037; cell_id=667904; Band=LTE_BAND_40
RAT:LTE, PLMNs found: 404/45(INA/AirTel);
TRACKING_AREA_UPDATE_REQUEST_AIRMSG
COMBINED_TA_LA_UPDATING
earfcn:39000 (TDD Band 40), pci:354, status:OK, num PRBs:100
L1E_MIB_IND
earfcn:39000 (TDD Band 40), pci:354, status:OK, num PRBs:100
rb:0; UL_CCCH: rrcConnectionRequest, cause:mo_Signalling
rb:0; DL_CCCH: rrcConnectionSetup, txMode:tm3, ttiBundling:no, ulHarqProcesses:5
rb:33; UL_DCCH: rrcConnectionSetupComplete; EPS:[ciphered]
rb:33; DL_DCCH: dlInformationTransfer; EPS:[ciphered]
result:TA_UPDATED_COMBINED_TA_LA_UPDATED
TRACKING_AREA_UPDATE_COMPLETE_AIRMSG



CSFB to UMTS network while UE was in connected mode and received paging for MT Call.
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1 comment:

  1. nice explanation......
    I have one doubt... How enodeb finds the redirected carrier info which it sends to UE in rrc connection release message?

    ReplyDelete

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