Thursday 8 December 2016

RRC Connection Reconfiguration

Signalling radio bearer: SRB1
RLC-SAP: AM
Logical channel: DCCH
Direction: E‑UTRAN to UE






The RRCConnectionReconfiguration message is the command to modify an RRC connection. It may convey information for measurement configuration, mobility control, radio resource configuration (including RBs, MAC main configuration and physical channel configuration) including any associated dedicated NAS information and security configuration.
RRCConnectionReconfiguration-r8-IEs:= SEQUENCE {
       MeasConfig                               MeasConfig
       MobilityControlInfo                     MobilityControlInfo
       DedicatedInfoNASList               SEQUENCE (SIZE (1…maxDRB)) OF DedicatedInfoNAS
       RadioResourceConfigDedicated                    RadioResourceConfigDedicated
       SecurityConfigHO                         SecurityConfigHO
}
RRCConnectionReconfiguration-v1020-IEs: = SEQUENCE {
       SCellToReleaseList-r10                   SCellToReleaseList-r10
       SCellToAddModList-r10                   SCellToAddModList-r10
}
Question: Why and what for “RRCConnectionReconfiguration” message is sent to UE although RRC connection is already there? What parameters are modified in the existing RRC?
RRC Connection Reconfiguration message is the command to modify an RRC connection.
Purpose of this procedure is to:
  • Establish/modify/release Radio bearers
  • Perform HO
  • Setup/modify/release Measurements
  • Add/modify/release secondary cells
  • NAS info might also transferred from eNB to UE
  • RRC Connection Reconfiguration is the only message used to perform all Logical, Transport and PHY channel configuration RRC.
Example: 1
DL_DCCH: rrcConnectionReconfiguration; TM3; measConfig EUTRA; srb:2; drb:4; EPS:[ciphered]
======================================================================
Pointer_1 : ASN1 Message -------- ASN1 3GPP 36.331 R11 value DL_DCCH_Message ::= { message c1 : rrcConnectionReconfiguration : { rrc_TransactionIdentifier 1, criticalExtensions c1 : rrcConnectionReconfiguration_r8 : { measConfig { measObjectToAddModList { { measObjectId 1, measObject measObjectEUTRA : { carrierFreq 1650, allowedMeasBandwidth mbw100 -- 5 --, presenceAntennaPort1 TRUE, neighCellConfig '00'B -- '00'H --, blackCellsToAddModList { { cellIndex 1, physCellIdRange { start 450 } } } } } }, reportConfigToAddModList { { reportConfigId 1, reportConfig reportConfigEUTRA : { triggerType event : { eventId eventA3 : { a3_Offset 6, reportOnLeave FALSE }, hysteresis 0, timeToTrigger ms320 -- 8 -- }, triggerQuantity rsrp -- 0 --, reportQuantity both -- 1 --, maxReportCells 8, reportInterval ms640 -- 3 --, reportAmount infinity -- 7 -- } }, { reportConfigId 2, reportConfig reportConfigEUTRA : { triggerType event : { eventId eventA5 : { a5_Threshold1 threshold_RSRP : 24, a5_Threshold2 threshold_RSRP : 26 }, hysteresis 0, timeToTrigger ms320 -- 8 -- }, triggerQuantity rsrp -- 0 --, reportQuantity both -- 1 --, maxReportCells 8, reportInterval ms640 -- 3 --, reportAmount infinity -- 7 -- } }, { reportConfigId 3, reportConfig reportConfigEUTRA : { triggerType event : { eventId eventA2 : { a2_Threshold threshold_RSRP : 20 }, hysteresis 0, timeToTrigger ms480 -- 9 -- }, triggerQuantity rsrp -- 0 --, reportQuantity sameAsTriggerQuantity -- 0 --, maxReportCells 8, reportInterval min60 -- 12 --, reportAmount r1 -- 0 -- } }, { reportConfigId 4, reportConfig reportConfigEUTRA : { triggerType event : { eventId eventA2 : { a2_Threshold threshold_RSRP : 22 }, hysteresis 0, timeToTrigger ms320 -- 8 -- }, triggerQuantity rsrp -- 0 --, reportQuantity sameAsTriggerQuantity -- 0 --, maxReportCells 8, reportInterval min60 -- 12 --, reportAmount r1 -- 0 -- } }, { reportConfigId 5, reportConfig reportConfigEUTRA : { triggerType periodical : { purpose reportStrongestCells -- 0 -- }, triggerQuantity rsrp -- 0 --, reportQuantity both -- 1 --, maxReportCells 8, reportInterval ms10240 -- 7 --, reportAmount infinity -- 7 -- } } }, measIdToAddModList { { measId 1, measObjectId 1, reportConfigId 1 }, { measId 2, measObjectId 1, reportConfigId 2 }, { measId 4, measObjectId 1, reportConfigId 3 }, { measId 6, measObjectId 1, reportConfigId 4 }, { measId 9, measObjectId 1, reportConfigId 5 } }, quantityConfig { quantityConfigEUTRA { } }, measGapConfig release : NULL, s_Measure 90, speedStatePars setup : { mobilityStateParameters { t_Evaluation s180 -- 3 --, t_HystNormal s180 -- 3 --, n_CellChangeMedium 10, n_CellChangeHigh 10 }, timeToTrigger_SF { sf_Medium oDot5 -- 1 --, sf_High oDot5 -- 1 -- } } }, dedicatedInfoNASList { '276929578B06074202491C0B64F010188218831884188518861887188818E418E518E618E718EA00705232C10506FFFFFFFF190533676E6574066D6E63303031066D63633436300 46770727305010A30B22B5D010030100B911F7396FEFE7649FFFF00FA0088003203813401005E06FEFEFA880000272280802110030100108106D21646038306D2165403000D04D2164 603000D04D2165403500BF664F0108800D0C6C0AC901364F010A8252305F480C2C517172C5949640100'H }, radioResourceConfigDedicated { srb_ToAddModList { { srb_Identity 2, rlc_Config explicitValue : am : { ul_AM_RLC { t_PollRetransmit ms100 -- 19 --, pollPDU pInfinity -- 7 --, pollByte kBinfinity -- 14 --, maxRetxThreshold t16 -- 6 -- }, dl_AM_RLC { t_Reordering ms50 -- 10 --, t_StatusProhibit ms0 -- 0 -- } }, logicalChannelConfig defaultValue : NULL } }, drb_ToAddModList { { eps_BearerIdentity 5, drb_Identity 4, pdcp_Config { discardTimer ms750 -- 5 --, rlc_AM { statusReportRequired TRUE }, headerCompression notUsed : NULL }, rlc_Config am : { ul_AM_RLC { t_PollRetransmit ms120 -- 23 --, pollPDU p64 -- 4 --, pollByte kB750 -- 8 --, maxRetxThreshold t16 -- 6 -- }, dl_AM_RLC { t_Reordering ms50 -- 10 --, t_StatusProhibit ms50 -- 10 -- } }, logicalChannelIdentity 3, logicalChannelConfig { ul_SpecificParameters { priority 9, prioritisedBitRate kBps8 -- 1 --, bucketSizeDuration ms300 -- 3 --, logicalChannelGroup 3 } } } }, mac_MainConfig explicitValue : { ul_SCH_Config { periodicBSR_Timer sf10 -- 1 --, retxBSR_Timer sf320 -- 0 --, ttiBundling FALSE }, drx_Config setup : { onDurationTimer psf10 -- 7 --, drx_InactivityTimer psf50 -- 11 --, drx_RetransmissionTimer psf8 -- 4 --, longDRX_CycleStartOffset sf320 : 206, shortDRX { shortDRX_Cycle sf80 -- 9 --, drxShortCycleTimer 2 } }, timeAlignmentTimerDedicated sf10240 -- 6 --, phr_Config setup : { periodicPHR_Timer sf20 -- 1 --, prohibitPHR_Timer sf0 -- 0 --, dl_PathlossChange dB3 -- 1 -- } }, physicalConfigDedicated { antennaInfo_r10 explicitValue_r10 : { transmissionMode_r10 tm3 -- 2 --, codebookSubsetRestriction_r10 '11'B -- 'C0'H --, ue_TransmitAntennaSelection release : NULL }, cqi_ReportConfig_r10 { cqi_ReportAperiodic_r10 setup : { cqi_ReportModeAperiodic_r10 rm30 -- 3 -- }, nomPDSCH_RS_EPRE_Offset 0, cqi_ReportPeriodic_r10 setup : { cqi_PUCCH_ResourceIndex_r10 8, cqi_pmi_ConfigIndex 44, cqi_FormatIndicatorPeriodic_r10 widebandCQI_r10 : { }, ri_ConfigIndex 1, simultaneousAckNackAndCQI TRUE } } } } } } }

Example:2
DL_DCCH: rrcConnectionReconfiguration; drb:4; NAS ESM:Modify EPS bearer context request
===================================================================
value DL_DCCH_Message ::= {  
         message c1 : rrcConnectionReconfiguration : {  
           rrc_TransactionIdentifier 1,  
           criticalExtensions c1 : rrcConnectionReconfiguration_r8 : {  
             dedicatedInfoNASList {  
               '279E374EF7025200C95B0506FFFFFFFF30100B911F7396FEFE7649FFFF00FA0088003203825E06FEFEFA880000'H  
             },  
             radioResourceConfigDedicated {  
               drb_ToAddModList {  
                 {  
                   drb_Identity 4,  
                   logicalChannelConfig {  
                     ul_SpecificParameters {  
                       priority 9,  
                       prioritisedBitRate kBps8  -- 1 --,  
                       bucketSizeDuration ms300  -- 3 --,  
                       logicalChannelGroup 3  
                     }  
                   }  
                 }  
               }  
rrcConnectionReconfiguration
UL_DCCH: rrcConnectionReconfigurationComplete
=======================================
value UL_DCCH_Message ::= {  
         message c1 : rrcConnectionReconfigurationComplete : {  
           rrc_TransactionIdentifier 1,  
           criticalExtensions rrcConnectionReconfigurationComplete_r8 : {  
           }  
         } 
rrcConnectionReconfigurationComplete

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