LTE 小区选择和重选
https://blog.csdn.net/wc_wc_8613/article/details/83866745
1. 小区选择
小区选择满足S准则，UE接入该小区：
R8: Srxlev > 0
R9: Srxlev > 0 AND Squal > 0
其中：
Srxlev = Qrxlevmeas – (Qrxlevmin + Qrxlevminoffset) – Pcompensation
Squal = Qqualmeas – (Qqualmin + Qqualminoffset)
其中:
Srxlev Cell selection RX level value (dB)
Squal Cell selection quality value (dB)
Qrxlevmeas UE Measured cell RX level value (RSRP)
Qqualmeas UE Measured cell quality value (RSRQ)
Qrxlevmin 小区最低接收功率 (dBm) sib1-> q-RxLevMin IE*2dbm
Qqualmin 小区最低接收质量 (dB) sib1-> q-QualMin-r9 IE*1db 不存在为负无穷
Qrxlevminoffset sib1-> q-RxLevMinOffset IE*2db 不存在为0
Qqualminoffset Sib1-> q-QualMinOffset-r9 IE*1db 不存在为0
Pcompensation max(PEMAX –PPowerClass, 0) (dB)
PEMAX 小区允许的UE最大功率 sib1-> p-Max
PPowerClass UE 最大输出功率
2. 小区重选
2.1 同频小区重选
2.1.1 测量开启
条件满足，UE开启测量：
R8: SServingCell <= Sintrasearch, or Sintrasearch is not sent in the serving cell
R9: Srxlev <= SIntraSearchP or Squal <= SIntraSearchQ
Srxlev Cell selection RX level value (dB)
Squal Cell selection quality value (dB)
SIntraSearchP Sib3-> s-IntraSearch / Sib3-> s-IntraSearchP-r9 IE*2db
SIntraSearchQ Sib3-> s-IntraSearchQ-r9 IE*1db
2.1.2 判决
小区排序准则：
| Rs = Qmeas,s + QHyst Rn = Qmeas,n - Qoffset
|
其中:
Qmeas RSRP measurement quantity used in cell reselections.
Rs 服务小区
Rn 邻区
Qhyst Sib3-> q-Hyst IE*1db
Qoffset
同频：sib4-> q-OffsetCell IE*1db 不存在则为0；
异频：sib5-> q-OffsetCell (不存在为0)+ sib5-> q-OffsetFreq,
若Rn > Rs 则执行重选。
对于满足S准则的小区，UE会进行排序（Rank）.若有多个小区满足重选标准，则按如下准则执行小区重选：
若最高优先级的小区是LTE小区，则在满足条件的小区中选择排名最高的LTE小区；
若最高优先级的小区是异系统小区，则在满足条件的小区中选择排名最高的RAT小区。
2.2 异频/异系统重选
2.2.1 测量开启
R8: SServingCell <= Snonintrasearch or Snonintrasearch is not sent in the serving cell
R9: Srxlev <= SnonIntraSearchP or Squal<=> SnonIntraSearchQ
高优先级邻区： 一直进行测量
同优先级或低优先级邻区： 满足上述条件，开启测量
Snonintrasearch Sib3-> s-NonIntraSearch IE*2db
SnonIntraSearchP Sib3-> s-NonIntraSearchP-r9 IE*2db
SnonIntraSearchQ Sib3-> s-NonIntraSearchQ-r9 IE*1db
2.2.2 判决
高优先级邻区
R8:
SnonServingCell,x > Threshx, high
R9：
邻区为EUTRAN or UTRAN FDD RAT/ frequency：
Squal > ThreshX, HighQ
邻区为UTRAN TDD, GERAN or CDMA2000 RAT/ frequency：
Srxlev > ThreshX, HighP
2.2.2 判决
高优先级邻区
R8:
SnonServingCell,x > Threshx, high
R9：
邻区为EUTRAN or UTRAN FDD RAT/ frequency：
Squal > ThreshX, HighQ
邻区为UTRAN TDD, GERAN or CDMA2000 RAT/ frequency：
Srxlev > ThreshX, HighP
Threshx, high Sib（5,6,7）->threshX-High IE*2db
ThreshX, HighQ Sib(5,6,7)-> threshX-HighQ-r9 IE*1db
ThreshX, HighP Sib（5,6,7）->threshX-High IE*2db
同优先级邻区
按照2.1.2要求。
低优先级邻区
R8:
服务小区： SServingCell < Threshserving, low
邻区 ： SnonServingCell,x > Threshx, low
R9:
邻区为EUTRAN or UTRAN FDD RAT/ frequency 小区：
服务小区：Squal < ThreshServing, LowQ
邻区 ： Squal > ThreshX, LowQ
邻区为UTRAN TDD, GERAN or CDMA2000 RAT/ frequency：
服务小区： Squal < ThreshServing, LowQ
邻区 ： Srxlev > ThreshX, LowP
hreshserving, low Sib3-> threshServingLow IE*2db
Threshx, low Sib(5,6,7)-> threshX-Low IE*2db
ThreshServing, LowQ Sib3-> threshServingLowQ-r9 IE*1db
ThreshX, LowQ Sib(5,6,7)-> threshX-LowQ-r9 IE*1db
ThreshX, LowP Sib(5,6,7)-> threshX-Low IE*2db
3. 参数汇总
Srxlev Cell selection RX level value (dB)
Squal Cell selection quality value (dB)
Qrxlevmeas UE Measured cell RX level value (RSRP)
Qqualmeas UE Measured cell quality value (RSRQ)
Qrxlevmin 小区最低接收功率 (dBm) sib1-> q-RxLevMin IE*2dbm
Qqualmin 小区最低接收质量 (dB) sib1-> q-QualMin-r9 IE*1db 不存在为负无穷
Qrxlevminoffset sib1-> q-RxLevMinOffset IE*2db 不存在为0
Qqualminoffset Sib1-> q-QualMinOffset-r9 IE*1db 不存在为0
Pcompensation max(PEMAX –PPowerClass, 0) (dB)
PEMAX 小区允许的UE最大功率 sib1-> p-Max
PPowerClass UE 最大输出功率
SIntraSearchP Sib3-> s-IntraSearch / Sib3-> s-IntraSearchP-r9 IE*2db
SIntraSearchQ Sib3-> s-IntraSearchQ-r9 IE*1db
Qmeas RSRP measurement quantity used in cell reselections.
Rs 服务小区
Rn 邻区
Qhyst Sib3-> q-Hyst IE*1db
Qoffset 同频：sib4-> q-OffsetCell IE*1db 不存在则为0；
异频：sib5-> q-OffsetCell (不存在为0)+ sib5-> q-OffsetFreq,
Threshx, high Sib（5,6,7）->threshX-High IE*2db
ThreshX, HighQ Sib(5,6,7)-> threshX-HighQ-r9 IE*1db
ThreshX, HighP Sib（5,6,7）->threshX-High IE*2db
Threshserving, low Sib3-> threshServingLow IE*2db
Threshx, low Sib(5,6,7)-> threshX-Low IE*2db
ThreshServing, LowQ Sib3-> threshServingLowQ-r9 IE*1db
ThreshX, LowQ Sib(5,6,7)-> threshX-LowQ-r9 IE*1db
ThreshX, LowP Sib(5,6,7)-> threshX-Low IE*2db
Snonintrasearch Sib3-> s-NonIntraSearch IE*2db
SnonIntraSearchP Sib3-> s-NonIntraSearchP-r9 IE*2db
SnonIntraSearchQ Sib3-> s-NonIntraSearchQ-r9 IE*1db
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作者：安得广厦
来源：CSDN
原文：https://blog.csdn.net/wc_wc_8613/article/details/83866745
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