LTE 小区选择和重选

小区选择和重选，都在Idle态下进行。

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

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

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

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