RRC Connection Reconfiguration in a nutshell



  • RRCConnectionReconfiguration in LTE does everything required to establish NR NSA
  • In NSA setup, this is the most important and complicated message you need to understand
  • Followings are several important configurations in this message
    • Measurement for NR cell : B1-NR event
    • NR Cell Information : Band, Frequency, SSB location, RACH configuration, Split Bearer Configuration
    • NR Carrier Aggregation (if NR CA is to be applied)




RRC ConnectionReconfiguration in Detail


As in LTE, RRC Reconfiguration is the most important steps in establishing Radio Connection between UE and Network. Understanding every details of RRC Reconfiguration would imply understanding almost everything in NR Radio Stack.  I would take around an year to get the understandings on the details of this single message to a certain degree and you would need to keep learning further details and new things throughout the whole life cycles of 5G/NR. So.. don't be too hurry trying to understand everything at a time and read / think on small pieces and analyze the protocol log when available whenever you have chance. This page also will be updated piece by piece and linked to many other pages for the details.




Overall Sequence of RRC Reconfiguration for NR


Following sequence shows what triggers NR RRC Reconfiguration on UE. As you see here, this can be triggered by LTE (in NSA(Non-Standalone) deployment) or by NR (in SA(Standalone) deployment).





Purpose (Function) of RRC Reconfiguration


As you can guess from the word itself, the major functionality of RrcReconfiguration is to setup or modify RRC configuration. This imply that there should have already been some RRC Configuration process before this message. It is true. In LTE, there is a step RrcConnectionSetup message before RrcConnectionReconfiguration and in NR there is RRC Setup message before RrcReconfiguration.



The major functionality of RRC Reconfiguration are to configure following RRC Components/Functions

  • Radio Bearer

  • Measurement

  • Scells or Cell Group


For each of the RRC Component/Functions, RrcReconfiguration message can do following operations

  • Radio Bearer
    • Establish
    • Modify
    • Release
  • Measurement
    • Setup
    • Modify
    • Release
  • Scells or Cell Group
    • Add

    • Modify

    • Release




What should UE do when it gets  RRCReconfiguration message ?


What should a UE do when it gets RrcReconfiguration message ? The answer is simple. Do whatever the message tell you to do. I know this is not the answer you want to hear :). Like in LTE, RRCReconfiguration is the most complicated message in NR. Understanding this message in full detail is like understanding the full protocol stack of NR. You will see a good framework or starting point of understanding this message in 3GPP 38.331 - Reception of an RRCReconfiguration by the UE. Followings are some of the highest level IE(Information Elements) that you may start with.



Since this message carries too many parameters (Information Elements), you would easily get lost if you try to go through each and every items from the beginning. I would suggest you to pick up any one of the high level items from the items listed above and try to understand the overall functionality of the high level item ,and then move to next item and get an overview and so on. When you have overall understandings on every items listed above, then move down to next level (one-step down) in each section.




RRC Reconfiguration Message structure


Followings are RRC Reconfiguration Message structure from 38.331. (NOTE : This is not necessarily from the latest specification. So just get the overal structure from this note and double check with 3GPP document version that you are specifically interested in).


RRCReconfiguration ::=              SEQUENCE {

    rrc-TransactionIdentifier           RRC-TransactionIdentifier,

    criticalExtensions                  CHOICE {

        rrcReconfiguration                  RRCReconfiguration-IEs,

        criticalExtensionsFuture            SEQUENCE {}





RRCReconfiguration-IEs ::=          SEQUENCE {

    radioBearerConfig           RadioBearerConfig   OPTIONAL, -- Need M

    secondaryCellGroup          OCTET STRING (CONTAINING CellGroupConfig) OPTIONAL, -- Need M

    measConfig                  MeasConfig  OPTIONAL, -- Need M

    lateNonCriticalExtension                OCTET STRING    OPTIONAL,

    nonCriticalExtension                    SEQUENCE {} OPTIONAL





< RadioBearerConfig >



RadioBearerConfig ::=                   SEQUENCE {

    srb-ToAddModList        SRB-ToAddModList    OPTIONAL, -- Need N

    srb3-ToRelease          ENUMERATED{true}    OPTIONAL, -- Need N

    drb-ToAddModList        DRB-ToAddModList    OPTIONAL, -- Need N

    drb-ToReleaseList       DRB-ToReleaseList   OPTIONAL, -- Need N

    securityConfig          SecurityConfig      OPTIONAL, -- Cond M






SRB-ToAddModList ::=                    SEQUENCE (SIZE (1..2)) OF SRB-ToAddMod


SRB-ToAddMod ::=    SEQUENCE {

    srb-Identity        SRB-Identity,

    reestablishPDCP     ENUMERATED{true}    OPTIONAL, - Need N

    discardOnPDCP       ENUMERATED{true}    OPTIONAL, -- Need N

    pdcp-Config         PDCP-Config     OPTIONAL, -- Cond PDCP






DRB-ToAddModList ::=                    SEQUENCE (SIZE (1..maxDRB)) OF DRB-ToAddMod

DRB-ToAddMod ::=                        SEQUENCE {

    cnAssociation                           CHOICE {

        eps-BearerIdentity                  INTEGER (0..15)      OPTIONAL,      

        sdap-Config                         SDAP-Config     OPTIONAL  


    drb-Identity                            DRB-Identity,

    reestablishPDCP                         ENUMERATED{true}     OPTIONAL,

    recoverPDCP                             ENUMERATED{true}     OPTIONAL,     

    pdcp-Config                             PDCP-Config          OPTIONAL, 





SDAP-Config ::= SEQUENCE {

   pdu-Session                PDU-SessionID,

   sdap-HeaderDL              ENUMERATED {present, absent},

   sdap-HeaderUL              ENUMERATED {present, absent},

   defaultDRB                 BOOLEAN,

   mappedQoS-FlowsToAdd       SEQUENCE (SIZE (1..maxNrofQFIs)) OF QFI OPTIONAL,

   mappedQoS-FlowsToRelease   SEQUENCE (SIZE (1..maxNrofQFIs)) OF QFI OPTIONAL,




QFI ::= INTEGER (0..maxQFI)

PDU-SessionID ::= INTEGER (0..255)


PDCP-Config ::= SEQUENCE {

    drb SEQUENCE {

        discardTimer ENUMERATED {ms10, ms20, ms30, ms40, ms50, ms60, ms75, ms100, ms150, ms200,

                            ms250, ms300, ms500, ms750, ms1500, infinity} OPTIONAL, --Cond Setup

        pdcp-SN-SizeUL ENUMERATED {len12bits, len18bits} OPTIONAL, -- Cond Setup2

        pdcp-SN-SizeDL ENUMERATED {len12bits, len18bits} OPTIONAL, -- Cond Setup2

        headerCompression CHOICE {

        notUsed NULL,

        rohc SEQUENCE {

            maxCID INTEGER (1..16383) DEFAULT 15,

            profiles SEQUENCE {

                profile0x0001 BOOLEAN,

                profile0x0002 BOOLEAN,

                profile0x0003 BOOLEAN,

                profile0x0004 BOOLEAN,

                profile0x0006 BOOLEAN,

                profile0x0101 BOOLEAN,

                profile0x0102 BOOLEAN,

                profile0x0103 BOOLEAN,

                profile0x0104 BOOLEAN


            drb-ContinueROHC ENUMERATED { true } OPTIONAL -- Need N


        uplinkOnlyROHC SEQUENCE {

            maxCID INTEGER (1..16383) DEFAULT 15,

            profiles SEQUENCE {

                profile0x0006 BOOLEAN


            drb-ContinueROHC ENUMERATED { true } OPTIONAL -- Need N




        integrityProtection ENUMERATED { enabled } OPTIONAL, -- Cond ConnectedTo5GC

        statusReportRequired ENUMERATED { true } OPTIONAL, -- Cond Rlc-AM

        outOfOrderDelivery ENUMERATED { true } OPTIONAL -- Need R

    } OPTIONAL, -- Cond DRB

    moreThanOneRLC SEQUENCE {

        primaryPath SEQUENCE {

            cellGroup              CellGroupId               OPTIONAL, -- Need R

            logicalChannel         LogicalChannelIdentity    OPTIONAL -- Need R


        ul-DataSplitThreshold      UL-DataSplitThreshold     OPTIONAL, -- Cond SplitBearer

        pdcp-Duplication           BOOLEAN                   OPTIONAL -- Need R


    t-Reordering ENUMERATED {

                        ms0, ms1, ms2, ms4, ms5, ms8, ms10, ms15, ms20, ms30, ms40,

                        ms50, ms60, ms80, ms100, ms120, ms140, ms160, ms180, ms200, ms220,

                        ms240, ms260, ms280, ms300, ms500, ms750, ms1000, ms1250,

                        ms1500, ms1750, ms2000, ms2250, ms2500, ms2750,

                        ms3000, spare28, spare27, spare26, spare25, spare24,

                        spare23, spare22, spare21, spare20,

                        spare19, spare18, spare17, spare16, spare15, spare14,

                        spare13, spare12, spare11, spare10, spare09,

                        spare08, spare07, spare06, spare05, spare04, spare03,

                        spare02, spare01 } OPTIONAL, -- Need S



    cipheringDisabled ENUMERATED {true} OPTIONAL -- Cond ConnectedTo5GC




UL-DataSplitThreshold ::= ENUMERATED {

    b0, b100, b200, b400, b800, b1600, b3200, b6400, b12800, b25600, b51200, b102400, b204800,

    b409600, b819200, b1228800, b1638400, b2457600, b3276800, b4096000, b4915200, b5734400,

    b6553600, infinity, spare8, spare7, spare6, spare5, spare4, spare3, spare2, spare1}



DRB-ToReleaseList ::=                   SEQUENCE (SIZE (1..maxDRB)) OF DRB-Identity



SecurityConfig ::=                      SEQUENCE {  

    securityAlgorithmConfig                 SecurityAlgorithmConfig    OPTIONAL, 

    keyToUse                                ENUMERATED{KeNB, S-KgNB}   OPTIONAL




SecurityAlgorithmConfig ::= SEQUENCE {

    cipheringAlgorithm           CipheringAlgorithm,

    integrityProtAlgorithm       IntegrityProtAlgorithm  OPTIONAL,   -- Need R   




IntegrityProtAlgorithm ::=  ENUMERATED {

                    nia0, nia1, nia2, nia3, spare4, spare3,

                    spare2, spare1, ...}


CipheringAlgorithm ::=  ENUMERATED {

                    nea0, nea1, nea2, nea3, spare4, spare3,

                    spare2, spare1, ...}



CellGroupConfig ::= SEQUENCE {

    cellGroupId CellGroupId,

    rlc-BearerToAddModList      SEQUENCE (SIZE(1..maxLC-ID)) OF RLC-Bearer-Config   OPTIONAL,  

    rlc-BearerToReleaseList     SEQUENCE (SIZE(1..maxLC-ID)) OF LogicalChannelIdentity  OPTIONAL,

    mac-CellGroupConfig         MAC-CellGroupConfig          OPTIONAL,

    physicalCellGroupConfig     PhysicalCellGroupConfig      OPTIONAL,

    spCellConfig                SpCellConfig                 OPTIONAL,

    sCellToAddModList           SEQUENCE (SIZE (1..maxNrofSCells)) OF SCellConfig   OPTIONAL,

    sCellToReleaseList          SEQUENCE (SIZE (1..maxNrofSCells)) OF SCellIndex    OPTIONAL,





MAC-CellGroupConfig ::=     SEQUENCE {

    drx-Config                  SetupRelease { DRX-Config } OPTIONAL, -- Need M

    schedulingRequestConfig     SchedulingRequestConfig     OPTIONAL, -- Need M

    bsr-Config                  BSR-Config                  OPTIONAL, -- Need M

    tag-Config                  TAG-Config                  OPTIONAL, -- Need M 

    phr-Config                  SetupRelease { PHR-Config } OPTIONAL, -- Need M

    skipUplinkTxDynamic         BOOLEAN,

    cs-RNTI                     SetupRelease { RNTI-Value } OPTIONAL -- Need M



DRX-Config ::=          SEQUENCE {

    drx-onDurationTimer     CHOICE {

                               subMilliSeconds INTEGER (1..31),

                               milliSeconds    ENUMERATED {

                                   ms1, ms2, ms3, ms4, ms5, ms6, ms8, ms10, ms20, ms30,

                                   ms40, ms50, ms60, ms80, ms100, ms200, ms300, ms400, ms500,

                                   ms600, ms800, ms1000, ms1200, ms1600, spare9, spare8, spare7,

                                   spare6, spare5, spare4, spare3, spare2, spare1 }


    drx-InactivityTimer        ENUMERATED {

                                   ms0, ms1, ms2, ms3, ms4, ms5, ms6, ms8, ms10, ms20, ms30,

                                   ms40, ms50, ms60, ms80, ms100, ms200, ms300, ms500, ms750,

                                   ms1280, ms1920, ms2560, spare9, spare8, spare7, spare6,

                                   spare5, spare4, spare3, spare2, spare1},

    drx-HARQ-RTT-TimerDL         INTEGER (0..56),

    drx-HARQ-RTT-TimerUL         INTEGER (0..56),

    drx-RetransmissionTimerDL    ENUMERATED {

                                   sl0, sl1, sl2, sl4, sl6, sl8, sl16, sl24, sl33, sl40, sl64,

                                   sl80, sl96, sl112, sl128, sl160, sl320, spare15, spare14,

                                   spare13, spare12, spare11, spare10, spare9, spare8, spare7,

                                   spare6, spare5, spare4, spare3, spare2, spare1},

    drx-RetransmissionTimerUL    ENUMERATED {

                                   sl0, sl1, sl2, sl4, sl6, sl8, sl16, sl24, sl33, sl40, sl64,

                                   sl80, sl96, sl112, sl128, sl160, sl320, spare15, spare14,

                                   spare13, spare12, spare11, spare10, spare9, spare8, spare7,

                                   spare6, spare5, spare4, spare3, spare2, spare1 },

    drx-LongCycleStartOffset        CHOICE {

        ms10                            INTEGER(0..9),

        ms20                            INTEGER(0..19),

        ms32                            INTEGER(0..31),

        ms40                            INTEGER(0..39),

        ms60                            INTEGER(0..59),

        ms64                            INTEGER(0..63),

        ms70                            INTEGER(0..69),

        ms80                            INTEGER(0..79),

        ms128                           INTEGER(0..127),

        ms160                           INTEGER(0..159),

        ms256                           INTEGER(0..255),

        ms320                           INTEGER(0..319),

        ms512                           INTEGER(0..511),

        ms640                           INTEGER(0..639),

        ms1024                          INTEGER(0..1023),

        ms1280                          INTEGER(0..1279),

        ms2048                          INTEGER(0..2047),

        ms2560                          INTEGER(0..2559),

        ms5120                          INTEGER(0..5119),

        ms10240                         INTEGER(0..10239)


    shortDRX              SEQUENCE {

        drx-ShortCycle        ENUMERATED  {

                                  ms2, ms3, ms4, ms5, ms6, ms7, ms8, ms10, ms14, ms16, ms20,

                                  ms30, ms32, ms35, ms40, ms64, ms80, ms128, ms160, ms256,

                                  ms320, ms512, ms640, spare9, spare8, spare7, spare6, spare5,

                                  spare4, spare3, spare2, spare1 },

        drx-ShortCycleTimer                 INTEGER (1..16)

    }       OPTIONAL,         -- Need R

    drx-SlotOffset                      INTEGER (0..31)




PHR-Config ::=                      SEQUENCE {

    phr-PeriodicTimer       ENUMERATED {sf10, sf20, sf50, sf100, sf200,sf500, sf1000, infinity},

    phr-ProhibitTimer       ENUMERATED {sf0, sf10, sf20, sf50, sf100,sf200, sf500, sf1000},

    phr-Tx-PowerFactorChange            ENUMERATED {dB1, dB3, dB6, infinity},

    multiplePHR                         BOOLEAN,

    phr-Type2PCell                      BOOLEAN,

    phr-Type2OtherCell                  BOOLEAN,

    phr-ModeOtherCG                     ENUMERATED {real, virtual}





TAG-Config ::=              SEQUENCE {

    tag-ToReleaseList         SEQUENCE (SIZE (1..maxNrofTAGs)) OF TAG-Id   OPTIONAL,-- Need N

    tag-ToAddModList          SEQUENCE (SIZE (1..maxNrofTAGs)) OF TAG-ToAddMod OPTIONAL -- Need N



TAG-ToAddMod ::=            SEQUENCE {

    tag-Id                      TAG-Id,

    timeAlignmentTimer          TimeAlignmentTimer,




TAG-Id ::=                  INTEGER (0..maxNrofTAGs-1)


TimeAlignmentTimer ::=      ENUMERATED {ms500, ms750, ms1280, ms1920, ms2560, ms5120,

                                        ms10240, infinity}


BSR-Config ::=              SEQUENCE {

    periodicBSR-Timer        ENUMERATED {

                                sf1, sf5, sf10, sf16, sf20, sf32, sf40, sf64, sf80, sf128,

                                sf160, sf320, sf640, sf1280, sf2560, infinity},

    retxBSR-Timer            ENUMERATED { sf10, sf20, sf40, sf80, sf160, sf320, sf640, sf1280,

                                sf2560, sf5120, sf10240, spare5, spare4,spare3, spare2, spare1},

    logicalChannelSR-DelayTimer     ENUMERATED { sf20, sf40, sf64, sf128, sf512, sf1024, sf2560,

                                                spare1}    OPTIONAL    -- Need R




SchedulingRequestConfig ::=         SEQUENCE {

    schedulingRequestToAddModList       SEQUENCE (SIZE (1..maxNrofSR-ConfigPerCellGroup)) OF

                                                SchedulingRequestToAddMod    OPTIONAL, -- Need N

    schedulingRequestToReleaseList      SEQUENCE (SIZE (1..maxNrofSR-ConfigPerCellGroup)) OF

                                                SchedulingRequestId          OPTIONAL  -- Need N



SchedulingRequestToAddMod ::=       SEQUENCE {

    sr-ConfigIndex      SchedulingRequestId,

    sr-ProhibitTimer                    ENUMERATED {ms1, ms2, ms4, ms8, ms16,

                                                    ms32, ms64, ms128}  OPTIONAL,   -- Need S

    sr-TransMax                         ENUMERATED {n4,n8,n16,n32,n64,spare3,spare2,spare1}



SchedulingRequestId ::= INTEGER (0..7)



CellGroupId ::=                  INTEGER (1.. maxSCellGroups)


LCH-Config ::=                   SEQUENCE {

    logicalChannelIdentity             LogicalChannelIdentity,

    servedRadioBearer                       INTEGER (1..32)       OPTIONAL,   

    reestablishRLC                          ENUMERATED {true}     OPTIONAL,   

    rlc-Config                              RLC-Config           OPTIONAL,  

    mac-LogicalChannelConfig                LogicalChannelConfig    OPTIONAL 



LogicalChannelIdentity ::=                  INTEGER (1..FFS)



PhysicalCellGroupConfig ::=                 SEQUENCE {

    harq-ACK-SpatialBundlingPUCCH       ENUMERATED {true}    OPTIONAL,   -- Need S

    harq-ACK-SpatialBundlingPUSCH       ENUMERATED {true}    OPTIONAL,   -- Need S

    p-NR                                P-Max                OPTIONAL,   -- Need R

    pdsch-HARQ-ACK-Codebook           ENUMERATED {semiStatic, dynamic},

    tpc-SRS-RNTI                        RNTI-Value           OPTIONAL,   -- Need R

    tpc-PUCCH-RNTI                      RNTI-Value           OPTIONAL,   -- Need R

    tpc-PUSCH-RNTI                      RNTI-Value           OPTIONAL,   -- Need R

    sp-CSI-RNTI                         RNTI-Value           OPTIONAL,   -- Cond SP-CSI-Report

    cs-RNTI                             SetupRelease { RNTI-Value }  OPTIONAL,    -- Need R





< MeasConfig >



MeasConfig ::= SEQUENCE {

    measObjectToRemoveList     MeasObjectToRemoveList OPTIONAL, -- Need N

    measObjectToAddModList     MeasObjectToAddModList OPTIONAL, -- Need N

    reportConfigToRemoveList   ReportConfigToRemoveList OPTIONAL, -- Need N

    reportConfigToAddModList   ReportConfigToAddModList OPTIONAL, -- Need N

    measIdToRemoveList         MeasIdToRemoveList OPTIONAL, -- Need N

    measIdToAddModList         MeasIdToAddModList OPTIONAL, -- Need N

    s-MeasureConfig CHOICE {

        ssb-RSRP RSRP-Range,

        csi-RSRP RSRP-Range

    } OPTIONAL, -- Need M

    quantityConfig             QuantityConfig OPTIONAL, -- Need M

    measGapConfig              MeasGapConfig OPTIONAL, -- Need M

    measGapSharingConfig       MeasGapSharingConfig OPTIONAL, -- Need M



MeasObjectToRemoveList ::= SEQUENCE (SIZE (1..maxNrofObjectId)) OF MeasObjectId

MeasIdToRemoveList ::= SEQUENCE (SIZE (1..maxNrofMeasId)) OF MeasId

ReportConfigToRemoveList ::= SEQUENCE (SIZE (1..maxReportConfigId)) OF ReportConfigId



MeasGapConfig ::= SEQUENCE {

    gapFR2 SetupRelease { GapConfig } OPTIONAL, -- Need M




GapConfig ::= SEQUENCE {

    gapOffset INTEGER (0..159),

    mgl ENUMERATED {ms1dot5, ms3, ms3dot5, ms4, ms5dot5, ms6},

    mgrp ENUMERATED {ms20, ms40, ms80, ms160},

    mgta ENUMERATED {ms0, ms0dot25, ms0dot5},





MeasGapSharingConfig ::= SEQUENCE {

    gapSharingFR2 SetupRelease { MeasGapSharingScheme } OPTIONAL, -- Need M



MeasGapSharingScheme ::= ENUMERATED { scheme00, scheme01, scheme10, scheme11 }



QuantityConfig ::= SEQUENCE {

    quantityConfigNR-List       SEQUENCE (SIZE (1..maxNrofQuantityConfig))

                                       OF QuantityConfigNR OPTIONAL, -- Need M




QuantityConfigNR::= SEQUENCE {

    quantityConfigCell         QuantityConfigRS,

    quantityConfigRS-Index     QuantityConfigRS OPTIONAL -- Need M



QuantityConfigRS ::= SEQUENCE {

    ssb-FilterConfig           FilterConfig,

    cs-RS-FilterConfig         FilterConfig



FilterConfig ::= SEQUENCE {

    filterCoefficientRSRP      FilterCoefficient DEFAULT fc4,

    filterCoefficientRSRQ      FilterCoefficient DEFAULT fc4,

    filterCoefficientRS-SINR   FilterCoefficient DEFAULT fc4





< SpcellConfig >



SpCellConfig ::=       SEQUENCE {

    servCellIndex                   ServCellIndex       OPTIONAL,   -- Cond SCG

    reconfigurationWithSync         ReconfigurationWithSync         OPTIONAL,  

    rlf-TimersAndConstants          etupRelease { RLF-TimersAndConstants } OPTIONAL,   -- Need M

    rlmInSyncOutOfSyncThreshold     INTEGER (0..1)                         OPTIONAL,   -- Need M

    spCellConfigDedicated           ServingCellConfig                   OPTIONAL,   -- Need M





ReconfigurationWithSync ::=         SEQUENCE {

    spCellConfigCommon                ServingCellConfigCommon       OPTIONAL,   -- Need M

    newUE-Identity                      RNTI-Value,

    t304                                ENUMERATED {ms50, ms100, ms150, ms200, ms500, ms1000

                                                   , ms2000, ms10000},

        rach-ConfigDedicated            CHOICE {

            uplink                              RACH-ConfigDedicated,

            supplementaryUplink                 RACH-ConfigDedicated

    }                                 OPTIONAL,   -- Need N





ServingCellConfig ::=       SEQUENCE {

    tdd-UL-DL-ConfigurationDedicated    TDD-UL-DL-ConfigDedicated   OPTIONAL,-- Cond TDD

    initialDownlinkBWP                  BWP-DownlinkDedicated  OPTIONAL,  -- Cond ServCellAdd

    downlinkBWP-ToReleaseList           SEQUENCE (SIZE (1..maxNrofBWPs)) OF BWP-Id  OPTIONAL,

    downlinkBWP-ToAddModList        SEQUENCE (SIZE (1..maxNrofBWPs)) OF BWP-Downlink OPTIONAL

    firstActiveDownlinkBWP-Id       BWP-Id      OPTIONAL,   -- Need R

    bwp-InactivityTimer         ENUMERATED {ms2, ms3, ms4, ms5, ms6, ms8, ms10, ms20,

                                            ms30, ms40,ms50, ms60, ms80, ms100, ms200,

                                            ms300, ms500, ms750, ms1280, ms1920, ms2560,

                                            spare10, spare9, spare8, spare7, spare6,

                                            spare5, spare4, spare3, spare2, spare1 } OPTIONAL, 

    defaultDownlinkBWP-Id       BWP-Id      OPTIONAL,   -- Need M

    uplinkConfig                UplinkConfig    OPTIONAL, -- Cond ServCellAdd-UL

    supplementaryUplink         UplinkConfig    OPTIONAL, -- Cond ServCellAdd-SUL

    pdsch-ServingCellConfig     SetupRelease { PDSCH-ServingCellConfig } OPTIONAL, -- Need M

    csi-MeasConfig              SetupRelease { CSI-MeasConfig } OPTIONAL,   -- Need M

    carrierSwitching            SetupRelease { SRS-CarrierSwitching} OPTIONAL,  -- Need M

    sCellDeactivationTimer      ENUMERATED {ms20, ms40, ms80, ms160, ms200, ms240, ms320,

                                            ms400, ms480, ms520, ms640, ms720, ms840,

                                            ms1280, spare2,spare1} OPTIONAL,-- Cond     ServingCellWithoutPUCCH

    crossCarrierSchedulingConfig    CrossCarrierSchedulingConfig    OPTIONAL,   -- Need M

    tag-Id                          TAG-Id,

    ue-BeamLockFunction             ENUMERATED {enabled}    OPTIONAL,   -- Need R

    pathlossReferenceLinking        ENUMERATED {pCell, sCell} OPTIONAL  -- Cond SCellOnly




PDSCH-ServingCellConfig ::=         SEQUENCE {

    codeBlockGroupTransmission       SetupRelease {


                                     }   OPTIONAL,   -- Need M

    xOverhead                        ENUMERATED { xOh6, xOh12, xOh18 }       OPTIONAL,-- Need S

    nrofHARQ-ProcessesForPDSCH       ENUMERATED {n2, n4, n6, n10, n12, n16}  OPTIONAL,-- Need S

    pucch-Cell                       ServCellIndex      OPTIONAL    ,   -- Cond SCellAddOnly





PDSCH-CodeBlockGroupTransmission ::=    SEQUENCE {

    maxCodeBlockGroupsPerTransportBlock     ENUMERATED {n2, n4, n6, n8},

    codeBlockGroupFlushIndicator            BOOLEAN,






UplinkConfig ::=    SEQUENCE {

    initialUplinkBWP            BWP-UplinkDedicated OPTIONAL,   -- Cond ServCellAdd.

    uplinkBWP-ToReleaseList     SEQUENCE (SIZE (1..maxNrofBWPs)) OF BWP-Id OPTIONAL,-- Need N

    uplinkBWP-ToAddModList      SEQUENCE (SIZE (1..maxNrofBWPs)) OF BWP-Uplink  OPTIONAL,

    firstActiveUplinkBWP-Id     BWP-Id  OPTIONAL,   -- Need R

    pusch-ServingCellConfig     SetupRelease { PUSCH-ServingCellConfig } OPTIONAL, 





ServingCellConfigCommon ::= SEQUENCE {

    physCellId                  PhysCellId  

    downlinkConfigCommon        DownlinkConfigCommon,

    uplinkConfigCommon          UplinkConfigCommon 

    supplementaryUplinkConfig   UplinkConfigCommon  

    n-TimingAdvanceOffset        ENUMERATED { n0, n25600, n39936 }

    ssb-PositionsInBurst        CHOICE {

        shortBitmap               BIT STRING (SIZE (4)),

        mediumBitmap              BIT STRING (SIZE (8)),

        longBitmap                BIT STRING (SIZE (64))

    }   OPTIONAL, -- Need R,

    ssb-periodicityServingCell      ENUMERATED { ms5, ms10, ms20, ms40, ms80, ms160,

                                                 spare2, spare1 }OPTIONAL,  -- Need S

    dmrs-TypeA-Position             ENUMERATED {pos2, pos3},

    lte-CRS-ToMatchAround           SetupRelease { RateMatchPatternLTE-CRS } OPTIONAL,  

    rateMatchPatternToAddModList    SEQUENCE (SIZE (1..maxNrofRateMatchPatterns)) OF


    rateMatchPatternToReleaseList   SEQUENCE (SIZE (1..maxNrofRateMatchPatterns)) OF


    ssbsubcarrierSpacing            SubcarrierSpacing   

    tdd-UL-DL-ConfigurationCommon   TDD-UL-DL-ConfigCommon   

    ss-PBCH-BlockPower              INTEGER (-60..50),





RateMatchPatternLTE-CRS ::= SEQUENCE {

    carrierFreqDL                   INTEGER (0..16383),

    carrierBandwidthDL              ENUMERATED {n6, n15, n25, n50, n75, n100, spare2, spare1},

    mbsfn-SubframeConfigList        EUTRA-MBSFN-SubframeConfigList OPTIONAL,

    nrofCRS-Ports                   ENUMERATED {n1, n2, n4},

    v-Shift                         ENUMERATED {n0, n1, n2, n3, n4, n5}




RateMatchPattern ::= SEQUENCE {

    rateMatchPatternId RateMatchPatternId,

    patternType CHOICE {

        bitmaps SEQUENCE {

        resourceBlocks              BIT STRING (SIZE (275)),

        symbolsInResourceBlock CHOICE {

            oneSlot                 BIT STRING (SIZE (14)),

            twoSlots                BIT STRING (SIZE (28))


        periodicityAndPattern CHOICE {

            n2                      BIT STRING (SIZE (2)),

            n4                      BIT STRING (SIZE (4)),

            n5                      BIT STRING (SIZE (5)),

            n8                      BIT STRING (SIZE (8)),

            n10                     BIT STRING (SIZE (10)),

            n20                     BIT STRING (SIZE (20)),

            n40                     BIT STRING (SIZE (40))

        } OPTIONAL, -- Need S



        controlResourceSet          ControlResourceSetId


        subcarrierSpacing           SubcarrierSpacing OPTIONAL, -- Cond CellLevel

        mode                        ENUMERATED { dynamic, semiStatic },





EUTRA-MBSFN-SubframeConfigList ::=

            SEQUENCE (SIZE (1..maxMBSFN-Allocations)) OF EUTRA-MBSFN-SubframeConfig


EUTRA-MBSFN-SubframeConfig ::= SEQUENCE {

    radioframeAllocationPeriod          ENUMERATED {n1, n2, n4, n8, n16, n32},

    radioframeAllocationOffset          INTEGER (0..7),

    subframeAllocation CHOICE {

        oneFrame                        BIT STRING (SIZE(6)),

        fourFrames                      BIT STRING (SIZE(24))


    subframeAllocation-v1430 CHOICE {

        oneFrame-v1430                  BIT STRING (SIZE(2)),

        fourFrames-v1430                BIT STRING (SIZE(8))

    } OPTIONAL, -- Need R






SubcarrierSpacing ::=  ENUMERATED {kHz15, kHz30, kHz60, kHz120, kHz240, spare3, spare2, spare1}



UplinkConfigCommon ::=      SEQUENCE {.

    frequencyInfoUL     FrequencyInfoUL     

    initialUplinkBWP    BWP-UplinkCommon    




FrequencyInfoDL ::=         SEQUENCE {

    absoluteFrequencySSB        ARFCN-ValueNR,

    frequencyBandList           MultiFrequencyBandListNR,

    absoluteFrequencyPointA     ARFCN-ValueNR,

    scs-SpecificCarrierList     SEQUENCE (SIZE (1..maxSCSs)) OF SCS-SpecificCarrier,





SCS-SpecificCarrier ::=             SEQUENCE {

    offsetToCarrier                     INTEGER (0..2199),

    subcarrierSpacing                   SubcarrierSpacing,

    carrierBandwidth                    INTEGER (1..maxNrofPhysicalResourceBlocks),



    txDirectCurrentLocation-v1530   INTEGER (0..4095)  OPTIONAL            -- Need S





absoluteFrequencySSB : Frequency of the SSB to be used for this serving cell. SSB related parameters (e.g. SSB index) provided for a serving cell refer to this SSB frequency unless mentioned otherwise. The frequency provided in this field identifies the position of resource element RE=#0 (subcarrier #0) of resource block RB#10 of the SS block. The cell-defining SSB of the PCell is always on the sync raster. Frequencies are considered to be on the sync raster if they are also identifiable with a GSCN value. If the field is absent, the SSB related parameters should be absent, e.g. ssb-PositionsInBurst, ssb-periodicityServingCell and subcarrierSpacing in ServingCellConfigCommon IE. If the field is absent, the UE obtains timing reference from the SpCell. This is only supported in case the Scell is in the same frequency band as the SpCell


absoluteFrequencyPointA :  Absolute frequency position of the reference resource block (Common RB 0). Its lowest subcarrier is also known as Point A. Note that the lower edge of the actual carrier is not defined by this field but rather in the scs-SpecificCarrierList. Corresponds to L1 parameter 'offset-ref-low-scs-ref-PRB' . See this page for further details.


carrierBandwidth : Width of this carrier in number of PRBs (using the subcarrierSpacing defined for this carrier) Corresponds to L1 parameter 'BW


offsetToCarrier : Offset in frequency domain between Point A (lowest subcarrier of common RB 0) and the lowest usable subcarrier on this carrier in number of PRBs (using the subcarrierSpacing defined for this carrier). The maximum value corresponds to 275*8-1. Corresponds to L1 parameter 'offset-pointA-low-scs'


SubcarrierSpacing : Subcarrier spacing of this carrier. It is used to convert the offsetToCarrier into an actual frequency. Only the values 15 or 30 kHz (<6GHz), 60 or 120 kHz (>6GHz) are applicable. The network configures all SCSs of configured BWPs configured in this serving cell. Corresponds to L1 parameter 'ref-scs'


txDirectCurrentLocation : Indicates the downlink Tx Direct Current location for the carrier. A value in the range 0..3299 indicates the subcarrier index within the carrier. The values in the value range 3301..4095 are reserved and ignored by the UE. If this field is absent, the UE assumes the default value of 3300 (i.e. "Outside the carrier").


offsetToPointA : The offset in PRB between the Point A and the lowest subcarrier of the lowest PRB of the cell-defining SSB after floating SSB is resolved. See this page for further details.


Example 01 : spCellConfig.FrequencyInfoDL


IE(Information Element)































FrequencyInfoUL ::=      SEQUENCE {

    frequencyBandList           MultiFrequencyBandListNR            

    absoluteFrequencyPointA     ARFCN-ValueNR                   

    scs-SpecificCarriers        SEQUENCE (SIZE (1..maxSCSs)) OF SCS-SpecificCarrier,

    additionalSpectrumEmission  AdditionalSpectrumEmission  

    p-Max               P-Max       

    frequencyShift7p5khz        ENUMERATED {true}





subcarrierSpacingCommon : Indicates Subcarrier spacing for SIB1, Msg.2/4 for initial access and SI-messages.

                            Values 15, and 30 kHz are applicable for carrier frequencies <6GHz;

                            Values 60 and 120 kHz are applicable for carrier frequencies >6GHz

ssb-subcarrieroffset :  The frequency domain offset between SSB and the overall resource block grid in number of subcarriers. Absence of the field indicates that no offset if applied (offset = 0). See 38.211,

ssb-PositionsInBurst : Indicates the time domain positions of the transmitted SS-blocks in an SS-burst. It corresponds to L1 parameter 'SSB-Transmitted' (see 38.213, section 4.1)

                         shortBitmap : bitmap for sub 3 GHz

                         mediumBitmap : bitmap for 3-6 GHz

                         longBitmap : bitmap for above 6 GHz

ssb-periodicityServingCell : The SSB periodicity in msec for the rate matching purpose (see 38.211-  

dmrs-TypeA-Position : Position of (first) DL DM-RS (see 38.211, section This field is usually in MIB. Assuming that the UE does not need to acquire MIB before sending RA to target cell, this parameter should also be here.

subcarrierSpacingSSB : Subcarrier spacing of SSB. Used only for non-initial access (e.g. SCells, PCell of SCG).

ss-PBCH-BlockPower : TX power that the NW used for SSB transmission. The UE uses it to estimate the RA preamble TX power

rach-ConfigCommon : Parameters that are also conveyed via system information (SIB1) but which are provided here to accelerate handover and to avoid that UEs need to read system information from SCells. See rach-ConfigCommon details in RACH page.


newUE-Identity : This is used as an RNTI assigning a C-RNTI to a UE. 38.331(v15.1)- states 'apply the value of the newUE-Identity as the C-RNTI for this cell group'




Example :


Example 01 : Initial NR Addition.

   Following is a RrcConnectionReconfiguration for NR Addition from Amarisoft. Click here to get the decoded message.