学习笔记之MIB相关

CORESET0时频域资源位置

SSB块与CORESET0的时频域资源都有很大的灵活性,使用MIB中有限的bit位数"pdcch-ConfigSIB1"(4MSB+4LSB)来表示两者的关系,必须对两者的映射关系做一定约束,也就是协议38.213的table 13-1~13-10与table 13-11~13-15。

MIB ::=                             SEQUENCE {
     
    systemFrameNumber                   BIT STRING (SIZE (6)),
    subCarrierSpacingCommon             ENUMERATED {
     scs15or60, scs30or120},
    ssb-SubcarrierOffset                INTEGER (0..15),
    dmrs-TypeA-Position                 ENUMERATED {
     pos2, pos3},
    pdcch-ConfigSIB1                    PDCCH-ConfigSIB1,
    cellBarred                          ENUMERATED {
     barred, notBarred},
    intraFreqReselection                ENUMERATED {
     allowed, notAllowed},
    spare                               BIT STRING (SIZE (1))
}
PDCCH-ConfigSIB1 ::=                SEQUENCE {
     
    controlResourceSetZero              ControlResourceSetZero,
    searchSpaceZero                     SearchSpaceZero
}
ControlResourceSetZero ::=                  INTEGER (0..15)
SearchSpaceZero ::=                 INTEGER (0..15)

ControlResourceSetZero即为4bit MSB,index取值0-15,查38213表table 13-1~13-10可确定符号数、PRB offset等配置;

SearchSpaceZero即为4bit LSB,index取值0-15,查表table 13-11~13-15,可确定SFN、时隙索引、时域相关配置;

以{ssb,pdcch}scs is {30,30}kHZ为例

学习笔记之MIB相关_第1张图片

  • For operation without shared spectrum channel access, a UE assumes that the offset in Tables 13-1 through 13-10 is defined with respect to the SCS of the CORESET for Type0-PDCCH CSS set, provided by subCarrierSpacingCommon, from the smallest RB index of the CORESET for Type0-PDCCH CSS set to the smallest RB index of the common RB overlapping with the first RB of the corresponding SS/PBCH block. In Tables 13-7, 13-8, and 13-10 Kssb is defined in [4, TS 38.211].
  • For operation with shared spectrum channel access, a UE determines an offset from a smallest RB index of the CORESET for Type0-PDCCH CSS set to a smallest RB index of the common RB overlapping with a first RB of the corresponding SS/PBCH block.

通过Pdcch-configSIB1查表可确定CORESET0与searchspacezero的时频域位置,终端“盲检”PDCCH,接收RMSI(SIB1)

SIB1 ::=        SEQUENCE {
     
    cellSelectionInfo                   SEQUENCE {
     
        q-RxLevMin                          Q-RxLevMin,
        q-RxLevMinOffset                    INTEGER (1..8)                                              OPTIONAL,   -- Need S
        q-RxLevMinSUL                       Q-RxLevMin                                                  OPTIONAL,   -- Need R
        q-QualMin                           Q-QualMin                                                   OPTIONAL,   -- Need S
        q-QualMinOffset                     INTEGER (1..8)                                              OPTIONAL    -- Need S
    }                                                                                                   OPTIONAL,   -- Cond Standalone
    cellAccessRelatedInfo               CellAccessRelatedInfo,
    connEstFailureControl               ConnEstFailureControl                                           OPTIONAL,   -- Need R
    si-SchedulingInfo                   SI-SchedulingInfo                                               OPTIONAL,   -- Need R
    servingCellConfigCommon             ServingCellConfigCommonSIB                                      OPTIONAL,   -- Need R
    ims-EmergencySupport                ENUMERATED {
     true}                                               OPTIONAL,   -- Need R
    eCallOverIMS-Support                ENUMERATED {
     true}                                               OPTIONAL,   -- Need R
    ue-TimersAndConstants               UE-TimersAndConstants                                           OPTIONAL,   -- Need R
    uac-BarringInfo                     SEQUENCE {
     
        uac-BarringForCommon                UAC-BarringPerCatList                                           OPTIONAL,   -- Need S
        uac-BarringPerPLMN-List             UAC-BarringPerPLMN-List                                         OPTIONAL,   -- Need S
        uac-BarringInfoSetList              UAC-BarringInfoSetList,
        uac-AccessCategory1-SelectionAssistanceInfo CHOICE {
     
            plmnCommon                           UAC-AccessCategory1-SelectionAssistanceInfo,
            individualPLMNList                   SEQUENCE (SIZE (2..maxPLMN)) OF UAC-AccessCategory1-SelectionAssistanceInfo
        }                                                                                                   OPTIONAL    -- Need S
    }                                                                                                   OPTIONAL,   -- Need R
    useFullResumeID                     ENUMERATED {
     true}                                               OPTIONAL,   -- Need R
    lateNonCriticalExtension            OCTET STRING                                                    OPTIONAL,
    nonCriticalExtension                SIB1-v1610-IEs                                                  OPTIONAL
}

SIB1-v1610-IEs ::=               SEQUENCE {
     
    idleModeMeasurementsEUTRA-r16    ENUMERATED{
     true}                                                   OPTIONAL,  -- Need R
    idleModeMeasurementsNR-r16       ENUMERATED{
     true}                                                   OPTIONAL,  -- Need R
    posSI-SchedulingInfo-r16         PosSI-SchedulingInfo-r16                                           OPTIONAL,  -- Need R
    nonCriticalExtension             SEQUENCE {
     }                                                        OPTIONAL
}

UAC-AccessCategory1-SelectionAssistanceInfo ::=    ENUMERATED {
     a, b, c}
ServingCellConfigCommonSIB ::=      SEQUENCE {
     
    downlinkConfigCommon                DownlinkConfigCommonSIB,
    uplinkConfigCommon                  UplinkConfigCommonSIB                                       OPTIONAL, -- Need R
    supplementaryUplink                 UplinkConfigCommonSIB                                       OPTIONAL, -- Need R
    n-TimingAdvanceOffset               ENUMERATED {
      n0, n25600, n39936 }                           OPTIONAL, -- Need S
    ssb-PositionsInBurst                SEQUENCE {
     
        inOneGroup                          BIT STRING (SIZE (8)),
        groupPresence                       BIT STRING (SIZE (8))                                   OPTIONAL  -- Cond FR2-Only
    },
    ssb-PeriodicityServingCell          ENUMERATED {
     ms5, ms10, ms20, ms40, ms80, ms160},
    tdd-UL-DL-ConfigurationCommon       TDD-UL-DL-ConfigCommon                                      OPTIONAL, -- Cond TDD
    ss-PBCH-BlockPower                  INTEGER (-60..50),
    ...,
    [[
    channelAccessMode-r16               CHOICE {
     
        dynamic                             NULL,
        semiStatic                          SemiStaticChannelAccessConfig
    }                                                                                               OPTIONAL, -- Cond SharedSpectrum
    discoveryBurstWindowLength-r16      ENUMERATED {
     ms0dot5, ms1, ms2, ms3, ms4, ms5}               OPTIONAL, -- Need R
    highSpeedConfig-r16                 HighSpeedConfig-r16                                         OPTIONAL  -- Need R
    ]]
}
DownlinkConfigCommonSIB ::=     SEQUENCE {
     
    frequencyInfoDL                 FrequencyInfoDL-SIB,
    initialDownlinkBWP              BWP-DownlinkCommon,
    bcch-Config                         BCCH-Config,
    pcch-Config                         PCCH-Config,
    ...
}

BCCH-Config ::=                 SEQUENCE {
     
    modificationPeriodCoeff         ENUMERATED {
     n2, n4, n8, n16},
    ...
}

PCCH-Config ::=             SEQUENCE {
     
    defaultPagingCycle                  PagingCycle,
    nAndPagingFrameOffset               CHOICE {
     
        oneT                                NULL,
        halfT                               INTEGER (0..1),
        quarterT                            INTEGER (0..3),
        oneEighthT                          INTEGER (0..7),
        oneSixteenthT                       INTEGER (0..15)
    },
    ns                                  ENUMERATED {
     four, two, one},
    firstPDCCH-MonitoringOccasionOfPO   CHOICE {
     
        sCS15KHZoneT                                                                SEQUENCE (SIZE (1..maxPO-perPF)) OF INTEGER (0..139),
        sCS30KHZoneT-SCS15KHZhalfT                                                  SEQUENCE (SIZE (1..maxPO-perPF)) OF INTEGER (0..279),
        sCS60KHZoneT-SCS30KHZhalfT-SCS15KHZquarterT                                 SEQUENCE (SIZE (1..maxPO-perPF)) OF INTEGER (0..559),
        sCS120KHZoneT-SCS60KHZhalfT-SCS30KHZquarterT-SCS15KHZoneEighthT             SEQUENCE (SIZE (1..maxPO-perPF)) OF INTEGER (0..1119),
        sCS120KHZhalfT-SCS60KHZquarterT-SCS30KHZoneEighthT-SCS15KHZoneSixteenthT    SEQUENCE (SIZE (1..maxPO-perPF)) OF INTEGER (0..2239),
        sCS120KHZquarterT-SCS60KHZoneEighthT-SCS30KHZoneSixteenthT                  SEQUENCE (SIZE (1..maxPO-perPF)) OF INTEGER (0..4479),
        sCS120KHZoneEighthT-SCS60KHZoneSixteenthT                                   SEQUENCE (SIZE (1..maxPO-perPF)) OF INTEGER (0..8959),
        sCS120KHZoneSixteenthT                                                      SEQUENCE (SIZE (1..maxPO-perPF)) OF INTEGER (0..17919)
    }      OPTIONAL,           -- Need R
    ...,
    [[
    nrofPDCCH-MonitoringOccasionPerSSB-InPO-r16                                  INTEGER (2..4)             OPTIONAL  -- Cond SharedSpectrum2
    ]]
}
FrequencyInfoDL-SIB ::=             SEQUENCE {
     
    frequencyBandList                   MultiFrequencyBandListNR-SIB,
    offsetToPointA                      INTEGER (0..2199),
    scs-SpecificCarrierList             SEQUENCE (SIZE (1..maxSCSs)) OF SCS-SpecificCarrier
}

通过SIB1可知offsetToPointA的值,计算可知PointA的值。拿大神图镇楼,侵删。
学习笔记之MIB相关_第2张图片摘自自由之路66
学习笔记之MIB相关_第3张图片添加链接描述

  • offset查表可得,from the smallest RB index of the CORESET0 to the smallest RB index of the common RB overlapping with the first RB of the corresponding SS/PBCH block.
  • OffsetToPointA,由基站侧SIB1配置,represents the frequency offset between point A and the lowest subcarrier of the lowest resource block,which has the subcarrier spacing provided by the higher-layer parameter subCarrierSpacingCommon and overlaps with the SS/PBCH block used by the UE for initial cell selection
  • Kssb,MIB配置
    在这里插入图片描述

FR1, kSSB的范围{0,1,2…,23} , 需要5个bit来表示—MIB指示了4bit,剩余1bit在PBCH payload(共8bit)中,详见38.212 clause 7.1.1

FR2, kSSB的范围{0,1,2…,11}, 4bit 足以表示这个范围

学习笔记之MIB相关_第4张图片

NR PBCH内容

学习笔记之MIB相关_第5张图片

NR PBCH的载荷为56bit,24bit高层配置+32bit物理层提供的PBCH,详见下图

学习笔记之MIB相关_第6张图片

总结:

  • SSB盲检得到,初始小区接入,UE按20ms的周期检测;
  • PointA在SIB1中指示,解析流程为,SSB→PBCH→MIB→Kssb,Offset→Type0-PDCCH→SIB1;
  • MIB中的SFN与Kssb会出现结合PBCH附加比特计算的情况;

部分引自
5G NR SSB和CORESET0复用模式
NR PointA

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