5G學習筆記之系統消息

時間  2021-04-05
標籤 spa code orm rem ast form class 欄目 Java 简体版
原文   原文鏈接 
參考資料：3GPP 38.300、3GPP 38.331
SI：System Information
MIB：Master Information Block
SIB：SystemInformation Block
SSB：Synchronization Signal Block
RMSI：Remaining Minimum SI，剩餘最小SI，即除MIB外的最小SI。
PSCell：Primary SCG Cell
BWP：Bandwidth Part
1. 系統消息

SI包括一個MIB和多個SIB。SI分爲最小SI 和其它SI。spa

（1）最小SI ：包括了初始接入和如何獲取其它SI的基本信息。code

  • MIB：包含了如何獲取SIB1的信息，以及其它。
    ★★ 攜帶的消息：systemFrameNumber、subCarrierSpacingCommon、 ssb-SubcarrierOffset、dmrs-TypeA-Position、pdcch-ConfigSIB一、cellBarred 、 intraFreqReselection（是否容許同頻重選）。
    ★★ MIB消息在BCH上週期性重複廣播，週期爲80ms。重複次數由SSB的週期決定。



  • SIB1：包括了初始接入須要的信息以及其它SI的調度信息。
    ★★ 攜帶的消息： cellSelectionInfo 、cellAccessRelatedInfo 、connEstFailureControl、si-SchedulingInfo、 servingCellConfigCommon、ims-EmergencySupport、eCallOverIMS-Support 、ue-TimersAndConstants 、uac-BarringInfo、useFullResumeID。
    ★★ SIB1也叫RMSI，剩餘最小SI，即除MIB外的最小SI。
    ★★ SIB1在DL-SCH上週期性重複廣播，週期爲160ms。在每一個週期內重複廣播的次數是不固定的，其取決於具體實現。默認是8次。
    ★★ 當UE處於RRC_CONNECTED態時，可經過週期廣播，或者經過RRCReconfiguration消息獲取SIB1。
    ★★ SIB1指示其它SI是週期性廣播，仍是按需提供。若按需提供其它SI，則SIB1還需包括UE執行SI請求的信息。




（2）其它SI：不包括在最小SI的其他全部系統消息。orm

  • 獲取其它SI的方式：
    ① 週期性廣播，其廣播信息由SIB1中攜帶的si-SchedulingInfo決定；
    ② 按需廣播（ RRC_IDLE、RRC_INACTIVE），或者經過RRCReconfiguration發送給特定UE（ RRC_CONNECTED）；

  • SIB2：包括了小區重選公共信息（同頻、異頻、RAT間），服務小區小區重選信息、同頻小區重選信息。
SIB2 ::=                            SEQUENCE {
    cellReselectionInfoCommon           SEQUENCE {
        nrofSS-BlocksToAverage              INTEGER (2..maxNrofSS-BlocksToAverage)          OPTIONAL,       -- Need R
        absThreshSS-BlocksConsolidation     ThresholdNR                                     OPTIONAL,       -- Need R
        rangeToBestCell                     RangeToBestCell                                 OPTIONAL,       -- Need R
        q-Hyst                              ENUMERATED {
                                                dB0, dB1, dB2, dB3, dB4, dB5, dB6, dB8, dB10,
                                                dB12, dB14, dB16, dB18, dB20, dB22, dB24},
        speedStateReselectionPars           SEQUENCE {
            mobilityStateParameters             MobilityStateParameters,
            q-HystSF                        SEQUENCE {
                sf-Medium                       ENUMERATED {dB-6, dB-4, dB-2, dB0},
                sf-High                         ENUMERATED {dB-6, dB-4, dB-2, dB0}
            }
        }                                                                                   OPTIONAL,       -- Need R
    ...
    },
    cellReselectionServingFreqInfo      SEQUENCE {
        s-NonIntraSearchP                   ReselectionThreshold                            OPTIONAL,       -- Need R
        s-NonIntraSearchQ                   ReselectionThresholdQ                           OPTIONAL,       -- Need R
        threshServingLowP                   ReselectionThreshold,
        threshServingLowQ                   ReselectionThresholdQ                           OPTIONAL,       -- Need R
        cellReselectionPriority             CellReselectionPriority,
        cellReselectionSubPriority          CellReselectionSubPriority                      OPTIONAL,       -- Need R
        ...
    },
    intraFreqCellReselectionInfo        SEQUENCE {
        q-RxLevMin                          Q-RxLevMin,
        q-RxLevMinSUL                       Q-RxLevMin                                      OPTIONAL,       -- Need R
        q-QualMin                           Q-QualMin                                       OPTIONAL,       -- Need S
        s-IntraSearchP                      ReselectionThreshold,
        s-IntraSearchQ                      ReselectionThresholdQ                           OPTIONAL,       -- Cond RSRQ
        t-ReselectionNR                     T-Reselection,
        frequencyBandList                   MultiFrequencyBandListNR-SIB                    OPTIONAL,       -- Need S
        frequencyBandListSUL                MultiFrequencyBandListNR-SIB                    OPTIONAL,       -- Need R
        p-Max                               P-Max                                           OPTIONAL,       -- Need R
        smtc                                SSB-MTC                                         OPTIONAL,       -- Need R
        ss-RSSI-Measurement                 SS-RSSI-Measurement                             OPTIONAL,       -- Need R
        ssb-ToMeasure                       SSB-ToMeasure                                   OPTIONAL,       -- Need R
        deriveSSB-IndexFromCell             BOOLEAN,
        ...,
        [[
        t-ReselectionNR-SF                  SpeedStateScaleFactors                          OPTIONAL        -- Need N
        ]]
    },
    ...
}

RangeToBestCell    ::= Q-OffsetRange
  • SIB3：包括了同頻鄰區信息和同頻黑名單小區信息，用於同頻小區重選。
SIB3 ::=                            SEQUENCE {
    intraFreqNeighCellList              IntraFreqNeighCellList      OPTIONAL,   -- Need R
    intraFreqBlackCellList              IntraFreqBlackCellList      OPTIONAL,   -- Need R
    lateNonCriticalExtension            OCTET STRING                OPTIONAL,
    ...
}

IntraFreqNeighCellList ::=          SEQUENCE (SIZE (1..maxCellIntra)) OF IntraFreqNeighCellInfo

IntraFreqNeighCellInfo ::=          SEQUENCE {
    physCellId                          PhysCellId,
    q-OffsetCell                        Q-OffsetRange,
    q-RxLevMinOffsetCell                INTEGER (1..8)              OPTIONAL,   -- Need R
    q-RxLevMinOffsetCellSUL             INTEGER (1..8)              OPTIONAL,   -- Need R
    q-QualMinOffsetCell                 INTEGER (1..8)              OPTIONAL,   -- Need R
    ...
}

IntraFreqBlackCellList ::=          SEQUENCE (SIZE (1..maxCellBlack)) OF PCI-Range
  • SIB4：包括了異頻小區重選信息，異頻鄰區信息，以及異頻黑名單小區信息，用於異頻小區重選。
SIB4 ::=                            SEQUENCE {
    interFreqCarrierFreqList            InterFreqCarrierFreqList,
    lateNonCriticalExtension            OCTET STRING                                OPTIONAL,
    ...
}

InterFreqCarrierFreqList ::=        SEQUENCE (SIZE (1..maxFreq)) OF InterFreqCarrierFreqInfo

InterFreqCarrierFreqInfo ::=        SEQUENCE {
    dl-CarrierFreq                      ARFCN-ValueNR,
    frequencyBandList                   MultiFrequencyBandListNR-SIB                OPTIONAL,   -- Cond Mandatory
    frequencyBandListSUL                MultiFrequencyBandListNR-SIB                OPTIONAL,   -- Need R
    nrofSS-BlocksToAverage              INTEGER (2..maxNrofSS-BlocksToAverage)      OPTIONAL,   -- Need R
    absThreshSS-BlocksConsolidation     ThresholdNR                                 OPTIONAL,   -- Need R
    smtc                                SSB-MTC                                     OPTIONAL,   -- Need R
    ssbSubcarrierSpacing                SubcarrierSpacing,
    ssb-ToMeasure                       SSB-ToMeasure                               OPTIONAL,   -- Need R
    deriveSSB-IndexFromCell             BOOLEAN,
    ss-RSSI-Measurement                 SS-RSSI-Measurement                         OPTIONAL,
    q-RxLevMin                          Q-RxLevMin,
    q-RxLevMinSUL                       Q-RxLevMin                                  OPTIONAL,   -- Need R
    q-QualMin                           Q-QualMin                                   OPTIONAL,   -- Need S,
    p-Max                               P-Max                                       OPTIONAL,   -- Need R
    t-ReselectionNR                     T-Reselection,
    t-ReselectionNR-SF                  SpeedStateScaleFactors                      OPTIONAL,    -- Need S
    threshX-HighP                       ReselectionThreshold,
    threshX-LowP                        ReselectionThreshold,
    threshX-Q                           SEQUENCE {
        threshX-HighQ                       ReselectionThresholdQ,
        threshX-LowQ                        ReselectionThresholdQ
    }                                                                               OPTIONAL,   -- Cond RSRQ
    cellReselectionPriority             CellReselectionPriority                     OPTIONAL,   -- Need R
    cellReselectionSubPriority          CellReselectionSubPriority                  OPTIONAL,   -- Need R
    q-OffsetFreq                        Q-OffsetRange                               DEFAULT dB0,
    interFreqNeighCellList              InterFreqNeighCellList                      OPTIONAL,   -- Need R
    interFreqBlackCellList              InterFreqBlackCellList                      OPTIONAL,   -- Need R
    ...
}

InterFreqNeighCellList ::=          SEQUENCE (SIZE (1..maxCellInter)) OF InterFreqNeighCellInfo

InterFreqNeighCellInfo ::=          SEQUENCE {
    physCellId                          PhysCellId,
    q-OffsetCell                        Q-OffsetRange,
    q-RxLevMinOffsetCell                INTEGER (1..8)                              OPTIONAL,   -- Need R
    q-RxLevMinOffsetCellSUL             INTEGER (1..8)                              OPTIONAL,   -- Need R
    q-QualMinOffsetCell                 INTEGER (1..8)                              OPTIONAL,   -- Need R
    ...

}

InterFreqBlackCellList ::=          SEQUENCE (SIZE (1..maxCellBlack)) OF PCI-Range
  • SIB5：包括了E-UTRA小區重選信息、E-UTRA小區信息，E-UTRA黑名單小區信息，用於RAT間小區重選。 
SIB5 ::=                            SEQUENCE {
    carrierFreqListEUTRA                CarrierFreqListEUTRA                        OPTIONAL,       -- Need R
    t-ReselectionEUTRA                  T-Reselection,
    t-ReselectionEUTRA-SF               SpeedStateScaleFactors                      OPTIONAL,       -- Need S
    lateNonCriticalExtension            OCTET STRING                                OPTIONAL,
    ...
}

CarrierFreqListEUTRA ::=            SEQUENCE (SIZE (1..maxEUTRA-Carrier)) OF CarrierFreqEUTRA

CarrierFreqEUTRA ::=                SEQUENCE {
    carrierFreq                         ARFCN-ValueEUTRA,
    eutra-multiBandInfoList             EUTRA-MultiBandInfoList                     OPTIONAL,       -- Need R
    eutra-FreqNeighCellList             EUTRA-FreqNeighCellList                     OPTIONAL,       -- Need R
    eutra-BlackCellList                 EUTRA-FreqBlackCellList                     OPTIONAL,       -- Need R
    allowedMeasBandwidth                EUTRA-AllowedMeasBandwidth,
    presenceAntennaPort1                EUTRA-PresenceAntennaPort1,
    cellReselectionPriority             CellReselectionPriority                     OPTIONAL,       -- Need R
    cellReselectionSubPriority          CellReselectionSubPriority                  OPTIONAL,       -- Need R
    threshX-High                        ReselectionThreshold,
    threshX-Low                         ReselectionThreshold,
    q-RxLevMin                          INTEGER (-70..-22),
    q-QualMin                           INTEGER (-34..-3),
    p-MaxEUTRA                          INTEGER (-30..33),
    threshX-Q                           SEQUENCE {
        threshX-HighQ                       ReselectionThresholdQ,
        threshX-LowQ                        ReselectionThresholdQ
    }                                                                               OPTIONAL        -- Cond RSRQ
}

EUTRA-FreqBlackCellList ::=         SEQUENCE (SIZE (1..maxEUTRA-CellBlack)) OF EUTRA-PhysCellIdRange

EUTRA-FreqNeighCellList ::=         SEQUENCE (SIZE (1..maxCellEUTRA)) OF EUTRA-FreqNeighCellInfo

EUTRA-FreqNeighCellInfo ::=         SEQUENCE {
    physCellId                          EUTRA-PhysCellId,
    q-OffsetCell                        EUTRA-Q-OffsetRange,
    q-RxLevMinOffsetCell                INTEGER (1..8)                              OPTIONAL,       -- Need R
    q-QualMinOffsetCell                 INTEGER (1..8)                              OPTIONAL        -- Need R
}
  • SIB6：ETWS主通知。
  • SIB7：ETWS輔通知
  • SIB8：CMAS告警通知
  • SIB9：GPS和UTC相關信息。UE可根據SIB9獲取GPS、UTC以及本地時間。
     
2. UE獲取系統消息

（1）UE什麼時候須要獲取系統消息？ci

  • 小區選擇（剛開機）、小區重選、從未覆蓋的區域到有覆蓋的區域、從其它RAT進入到當前RAT、收到系統消息變動的指示、收到PWS通知、存儲的SI已過時、after reconfiguration with sync completion。

（2）UE如何獲取系統消息？rem

  • 獲取MIB和SIB1：
    ★★ 當UE獲取MIB和SIB1消息失敗時，則認爲該小區禁止接入。
    ★★ 處於RRC_IDLE或 RRC_INACTIVE的UE，根據38.213協議所述，在BCCH信道上獲取MIB消息；
    ★★ 處於RRC_IDLE、 RRC_INACTIVE，或已激活BWP，searchSpaceSIB1 和pagingSearchSpace配置了公共搜索空間且被指示系統消息已變動RRC_CONNECTED的UE，根據MIB消息，在DL-SCH信道上獲取SIB1。


    it

  • 獲取其它SI：io

（3）UE存儲系統消息

ast


  •  
3. 系統消息的有效性
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