在5G(NR)网络提出后，3GPP针对终端在空闲态下4G->5G的重选制定了特定的系统消息SIB24；其在4G(LTE)网络中进行广播，以供终端从4G重选到5G，而SIB24消息中的主要内容如下：

SIB 24( InterRAT/NR Neighbouring cells for cell reselection).

SystemInformationBlockType24-r15 ::= SEQUENCE {

carrierFreqListNR-r15                              CarrierFreqListNR-r15 OPTIONAL, -- Need----NR载频列表

t-ReselectionNR-r15                               T-Reselection,                                         ----NR重选指示

t-ReselectionNR-SF-r15                          SpeedStateScaleFactors OPTIONAL, -- Need OR ----NR重选速度因子

lateNonCriticalExtension                          OCTET STRING OPTIONAL,...}

CarrierFreqListNR-r15                                     ::= SEQUENCE (SIZE (1..maxFreq)) OF CarrierFreqNR-r15

CarrierFreqNR-r15 ::= SEQUENCE {

carrierFreq-r15                                     ARFCN-ValueNR-r15,                           ----NR载频点列表

multiBandInfoList-r15                             MultiFrequencyBandListNR-r15 OPTIONAL, -- Need OR

multiBandInfoListSUL-r15                        MultiFrequencyBandListNR-r15 OPTIONAL, -- Need OR

measTimingConfig-r15                            MTC-SSB-NR-r15 OPTIONAL, -- Need OR ----NR小区(SSB MTC) subcarrierSpacingSSB-r15                      ENUMERATED {kHz15, kHz30, kHz120, kHz240},----NR子载波间隔

ss-RSSI-Measurement-r15                     SS-RSSI-Measurement-r15 OPTIONAL, -- Cond RSRQ2---NR RSSI测量 

cellReselectionPriority-r15                      CellReselectionPriority OPTIONAL, -- Need OP

cellReselectionSubPriority-r15                 CellReselectionSubPriority-r13 OPTIONAL, -- Need OR

threshX-High-r15                                  ReselectionThreshold,       ---NR  重选的X-High

threshX-Low-r15                                  ReselectionThreshold,         ---NR 重选的X-LOW

threshX-Q-r15 SEQUENCE {

threshX-HighQ-r15                       ReselectionThresholdQ-r9,

threshX-LowQ-r15                       ReselectionThresholdQ-r9

} OPTIONAL, -- Cond RSRQ

q-RxLevMin-r15                                   INTEGER (-70..-22),               ---NR 重选主小区最小接入电平 

q-RxLevMinSUL-r15                              INTEGER (-70..-22) OPTIONAL, -- Need OR  ---NR 重选SUL小区最小接入电平 

p-MaxNR-r15                                       P-MaxNR-r15,                             ---NR小最大发射功率

ns-PmaxListNR-r15                               NS-PmaxListNR-r15 OPTIONAL, -- Need OR

q-QualMin-r15                                     INTEGER (-43..-12) OPTIONAL, -- Need OP

deriveSSB-IndexFromCell-r15                 BOOLEAN,

maxRS-IndexCellQual-r15                      MaxRS-IndexCellQualNR-r15 OPTIONAL, -- Need OR

threshRS-Index-r15                             ThresholdListNR-r15 OPTIONAL, -- Need OR

...,

[[ multiBandNsPmaxListNR-v1550            MultiBandNsPmaxListNR-1-v1550 OPTIONAL, -- Need OR

multiBandNsPmaxListNR-SUL-v1550         MultiBandNsPmaxListNR-v1550 OPTIONAL, -- Need OR

ssb-ToMeasure-r15                              SSB-ToMeasure-r15 OPTIONAL -- Need OR

]]}

MultiBandNsPmaxListNR-1-v1550    ::= SEQUENCE (SIZE (1.. maxMultiBandsNR-1-r15)) OF NS-PmaxListNR-r15

MultiBandNsPmaxListNR-v1550       ::= SEQUENCE (SIZE (1.. maxMultiBandsNR-r15)) OF NS-PmaxListNR-r15

原文来自：www.sharetechnote.com
整理：kangguoying20201206
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