下载文档原格式
LTE系统事件简介一、LTE事件概述LTE切换时需要UE上报测量的结果（包括RSRP，RSRQ等），而上报又分为周期性上报和事件触发的上报。
➢周期性上报由基站配置，UE直接上报测量的结果。
➢事件触发的上报又分为系统内的事件和系统间的事件。
LTE系统内切换主要事件包括：➢A1事件，服务小区质量高于门限；这个事件可以用来关闭频间测量。
➢A2事件，服务小区质量低于门限；这个事件可以用来打开频间测量和系统间测量，因为这个事件发生后可能发生切换等操作。
➢A3事件，邻小区质量好于服务小区质量；这个事件一般用于频内/间基于覆盖的切换。
➢A4事件，邻小区质量好于门限；这个事件一般用于基于负荷的切换。
➢A5事件，服务小区质量低于一个门限并且邻小区质量高于一个门限；这个事件也可以用于频内/间基于覆盖的切换。
目前LTE同频切换都是基于A3/A5事件进行的切换（现网主要是基于A3事件的）二、切换流程举例三、切换流程简要说明- RRC Connection Reconfiguration（Measurement Control）测量控制，一般在初始接入或上一次切换命令中的重配消息里携带- Measurement Report测量报告，终端根据当前小区的测量控制信息，将符合切换门限的小区进行上报- HO Request源小区在收到测量报告后向目标小区申请资源及配置信息（站内切换的话为站内交互，站间切换会使用X2口或者S1口，优先使用X2口）- HO Request Ack目标小区将终端的接纳信息以及其它配置信息反馈给源小区- RRC Connection Reconfiguration（HO Command）将目标小区的接纳信息及配置信息发给终端，告知终端目标小区已准备好终端接入，重配消息里包含目标小区的测量控制- SN Status Transfer源小区将终端业务的缓存数据移至目标小区- Random Access Preamble终端收到第5步重配消息（切换命令）后使用重配消息里的接入信息进行接入- Random Access Response目标小区接入响应，收到此命令后可认为接入完成了，然后终端在RRC层上发重配完成消息（第9步）- RRC Connect Reconfiguration complete（HO Confirm）上报重配完成消息，切换完成- Release Resource当终端成功接入后，目标小区通知源小区删除终端的上下文信息四、协议对LTE事件的定义和说明4.1 A1事件定义Event A1 (Serving becomes better than threshold)The UE shall:1> consider the entering condition for this event to be satisfied when condition A1-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A1-2, as specifiedbelow, is fulfilled;1> for this measurement, consider the primary or secondary cell that is configured on the frequencyindicated in the associated measObjectEUTRA to be the serving cell;Inequality A1-1 (Entering condition)-Ms>HysThreshInequality A1-2 (Leaving condition)Ms<+ThreshHysThe variables in the formula are defined as follows:Ms is the measurement result of the serving cell, not taking into account any offsets.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Thresh is the threshold parameter for this event (i.e. a1-Threshold as defined within reportConfigEUTRA for this event).Ms is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Hys is expressed in dB.Thresh is expressed in the same unit as Ms.4.2 A2事件定义Event A2 (Serving becomes worse than threshold)The UE shall:1> consider the entering condition for this event to be satisfied when condition A2-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A2-2, as specifiedbelow, is fulfilled;1> for this measurement, consider the primary or secondary cell that is configured on the frequencyindicated in the associated measObjectEUTRA to be the serving cell;Inequality A2-1 (Entering condition)+Ms<HysThreshInequality A2-2 (Leaving condition)Ms>-HysThreshThe variables in the formula are defined as follows:Ms is the measurement result of the serving cell, not taking into account any offsets.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Thresh is the threshold parameter for this event (i.e. a2-Threshold as defined within reportConfigEUTRA for this event).Ms is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Hys is expressed in dB.Thresh is expressed in the same unit as Ms.4.3 A3事件定义Event A3 (Neighbour becomes offset better than PCell)The UE shall:1> consider the entering condition for this event to be satisfied when condition A3-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A3-2, as specifiedbelow, is fulfilled;NOTE The cell(s) that triggers the event is on the frequency indicated in the associated measObject which may be different from the (primary) frequency used by the PCell.Inequality A3-1 (Entering condition)++>+Mn++-OcnOfpOcpMpHysOffOfnInequality A3-2 (Leaving condition)++<Mn++++MpOcpOfnOfpOffHysOcnThe variables in the formula are defined as follows:Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ofn is the frequency specific offset of the frequency of the neighbour cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell).Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Mp is the measurement result of the PCell, not taking into account any offsets.Ofp is the frequency specific offset of the primary frequency (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the primary frequency).Ocp is the cell specific offset of the PCell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the primary frequency), and is set to zero if not configured for the PCell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Off is the offset parameter for this event (i.e. a3-Offset as defined within reportConfigEUTRA for this event).Mn, Mp are expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ofn, Ocn, Ofp, Ocp, Hys, Off are expressed in dB.4.4 A4事件定义Event A4 (Neighbour becomes better than threshold)The UE shall:1> consider the entering condition for this event to be satisfied when condition A4-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A4-2, as specifiedbelow, is fulfilled;Inequality A4-1 (Entering condition)-+Mn>+HysThreshOcnOfnInequality A4-2 (Leaving condition)Mn<+++ThreshOfnHysOcnThe variables in the formula are defined as follows:Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ofn is the frequency specific offset of the frequency of the neighbour cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell).Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Thresh is the threshold parameter for this event (i.e. a4-Threshold as defined within reportConfigEUTRA for this event).Mn is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ofn, Ocn, Hys are expressed in dB.Thresh is expressed in the same unit as Mn.4.5 A5事件定义Event A5 (PCell becomes worse than threshold1 and neighbour becomes better than threshold2)The UE shall:1> consider the entering condition for this event to be satisfied when both condition A5-1 andcondition A5-2, as specified below, are fulfilled;1> consider the leaving condition for this event to be satisfied when condition A5-3 or condition A5-4, i.e. at least one of the two, as specified below, is fulfilled;NOTE: The cell(s) that triggers the event is on the frequency indicated in the associatedmeasObject which may be different from the (primary) frequency used by the PCell.Inequality A5-1 (Entering condition 1)1Thresh Hys Mp <+Inequality A5-2 (Entering condition 2)2Thresh Hys Ocn Ofn Mn >-++Inequality A5-3 (Leaving condition 1)1Thresh Hys Mp >-Inequality A5-4 (Leaving condition 2)2Thresh Hys Ocn Ofn Mn <+++The variables in the formula are defined as follows:Mp is the measurement result of the PCell, not taking into account any offsets.Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ofn is the frequency specific offset of the frequency of the neighbour cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell).Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Thresh1 is the threshold parameter for this event (i.e. a5-Threshold1 as defined within reportConfigEUTRA for this event).Thresh2 is the threshold parameter for this event (i.e. a5-Threshold2 as defined within reportConfigEUTRA for this event).Mn, Mp are expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ofn, Ocn, Hys are expressed in dB.Thresh1 is expressed in the same unit as Mp .Thresh2 is expressed in the same unit as Mn .Event A6 (Neighbour becomes offset better than SCell)The UE shall:1> consider the entering condition for this event to be satisfied when condition A6-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A6-2, as specifiedbelow, is fulfilled;1> for this measurement, consider the (secondary) cell that is configured on the frequency indicatedin the associated measObjectEUTRA to be the serving cell;NOTE: The neighbour(s) is on the same frequency as the SCell i.e. both are on the frequency indicated in the associated measObject.Inequality A6-1 (Entering condition)+>Mn++-MsOcsOffHysOcnInequality A6-2 (Leaving condition)+<+Mn++OcsOffMsHysOcnThe variables in the formula are defined as follows:Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Ms is the measurement result of the serving cell, not taking into account any offsets.Ocs is the cell specific offset of the serving cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the serving frequency), and is set to zero if not configured for the serving cell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Off is the offset parameter for this event (i.e. a6-Offset as defined within reportConfigEUTRA for this event).Mn, Ms are expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ocn, Ocs, Hys, Off are expressed in dB.Event B1 (Inter RAT neighbour becomes better than threshold)The UE shall:1> for UTRA and CDMA2000, only trigger the event for cells included in the correspondingmeasurement object;1> consider the entering condition for this event to be satisfied when condition B1-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition B1-2, as specifiedbelow, is fulfilled;Inequality B1-1 (Entering condition)Thresh+Mn>-HysOfnInequality B1-2 (Leaving condition)++Mn<ThreshHysOfnThe variables in the formula are defined as follows:Mn is the measurement result of the inter-RAT neighbour cell, not taking into account any offsets.For CDMA 2000 measurement result, pilotStrength is divided by -2.Ofn is the frequency specific offset of the frequency of the inter-RAT neighbour cell (i.e. offsetFreq as defined within the measObject corresponding to the frequency of the neighbour inter-RAT cell).Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigInterRAT for this event).Thresh is the threshold parameter for this event (i.e. b1-Threshold as defined within reportConfigInterRAT for this event). For CDMA2000, b1-Threshold is divided by -2.Mn is expressed in dBm or in dB, depending on the measurement quantity of the inter-RAT neighbour cell.Ofn, Hys are expressed in dB.Thresh is expressed in the same unit as Mn.4.8 B2事件定义Event B2 (PCell becomes worse than threshold1 and inter RAT neighbour becomes better than threshold2)The UE shall:1> for UTRA and CDMA2000, only trigger the event for cells included in the correspondingmeasurement object;1> consider the entering condition for this event to be satisfied when both condition B2-1 andcondition B2-2, as specified below, are fulfilled;1> consider the leaving condition for this event to be satisfied when condition B2-3 or conditionB2-4, i.e. at least one of the two, as specified below, is fulfilled;Inequality B2-1 (Entering condition 1)+HysMp<Thresh1Inequality B2-2 (Entering condition 2)-+Mn>Ofn2ThreshHysInequality B2-3 (Leaving condition 1)Hys-Mp>1ThreshInequality B2-4 (Leaving condition 2)Mn<++OfnHys2ThreshThe variables in the formula are defined as follows:Mp is the measurement result of the PCell, not taking into account any offsets.Mn is the measurement result of the inter-RAT neighbour cell, not taking into account any offsets.For CDMA2000 measurement result, pilotStrength is divided by -2.Ofn is the frequency specific offset of the frequency of the inter-RAT neighbour cell (i.e. offsetFreq as defined within the measObject corresponding to the frequency of the inter-RAT neighbourcell).Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigInterRAT for this event).Thresh1 is the threshold parameter for this event (i.e. b2-Threshold1 as defined within reportConfigInterRAT for this event).Thresh2 is the threshold parameter for this event (i.e. b2-Threshold2 as defined within reportConfigInterRAT for this event). For CDMA2000, b2-Threshold2 is divided by -2.Mp is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Mn is expressed in dBm or dB, depending on the measurement quantity of the inter-RAT neighbour cell.Ofn, Hys are expressed in dB.修正版Thresh1 is expressed in the same unit as Mp. Thresh2 is expressed in the same unit as Mn.。
1 4.5.1 切换正常流程同频切换同时支持同eNodeB切换，同MME的异eNodeB切换，跨MME的异eNodeB切换场景。
对于后两种场景依据eNodeB间是否建立X2接口，切换信令流程略有不同。
图4-2 同MME异eNodeB间切换流程同MME异eNodeB间的同频切换信令流程如图4-2所示：1. 在无线承载建立时，源eNodeB下发RRC ConnectionReconfiguration至UE，其中包含source eNodeB 配置的Measurement Configuration消息，用于控制UE连接态的测量过程。
2. UE根据测量结果上报Measurement Report。
3. 源eNodeB根据测量报告进行切换决策。
4. 当源eNodeB决定切换后，源eNodeB发出HandoverRequest消息给目标eNodeB，通知目标eNodeB准备切换。
5. 目标eNodeB进行准入判断，若判断为资源准入，再由目标eNodeB依据EPS的QoS信息执行准入控制。
6. 目标eNodeB在L1/L2准备切换并对源eNodeB发送HANDOVERREQUEST ACKNOWLEDGE消息。
3.1.2 报告配置事件触发上报是3GPP 36.331协议中为切换测量与判决定义的一个概念。
报告配置包含相应事件的相关参数。
目前eNodeB应用以下事件触发相应动作：事件A1表示服务小区质量高于一定门限，当满足事件触发条件时UE便上报测量报告，eNodeB停止异频/异系统测量。
但在基于频率优先级的切换中，事件A1用于启动异频测量。
事件A2表示服务小区质量低于一定门限，当满足事件触发条件时UE便上报测量报告，eNodeB启动异频/异系统测量。
但在基于频率优先级的切换中，事件A2用于停止异频测量。
事件A3表示同频/异频邻区质量相比服务小区质量高出一定门限，当满足事件触发条件的小区信息被上报时，源eNodeB启动同频/异频切换请求。
LTE 支持的切换事件有A 类和B 类，其中A 类本用作系统内测量，B 类被用作系统间测量A1事件：表示服务小区信号质量高于一定门限； A2事件：表示服务小区信号质量低于一定门限；A3事件：表示邻区质量高于服务小区质量，用于同频、异频的基于覆盖的切换； A4事件：表示邻区质量高于一定门限，用于基于负荷的切换，可用于负载均衡；A5事件：表示服务小区质量低于一定门限并且邻区质量高于一定门限，可用于负载均衡; 异系统测量事件： B1事件：邻小区质量高于一定门限，用于测量高优先级的异系统小区；B2事件：服务小区质量低于一定门限，并且邻小区质量高于一定门限，用于相同或较低优先级的异系统小区的测量。
LTE 移动性参数(全局)最小接入电平基本信息参数功能该参数表示UE 在该小区驻留需满足的最小接收电平门限。
该值取值范围是2G/3G 接收电平的实际值，对于LTE/3G ,?实际的RxlevMin?等于SIB3/SIB6的IE value 的两倍，调整步长为2dbm 。
对于2G ，实际的RxlevMin 等于SIB7的?(IE value * 2)? ?115，调整步长为2dBm 当UE 测量到的2G/3G 电平满足S 准则时，UE 才可能驻留在该小区。
参数调整影响调整该参数的门限值，会对小区的选择和驻留有所影响。
QrxLevMin 如果设置过高，则UE 将无法驻留到该小区。
高优先级重选门限基本信息参数功能当高优先级小区的S值在一定时间内高于该阀值(threshXHigh)后，UE可以重选到该小区。
参数调整影响调整该参数的门限值，会对小区的选择和驻留有所影响。
threshXhigh如果设置过高，?会增加UE重选到高优先级小区的难度。
低优先级重选门限基本信息参数功能当低优先级小区的S值在一定时间内高于该阀值(threshXLow)后，同时主服务小区的S值低于threshServingLow，UE可以重选到该低优先级小区。
LTE系统事件介绍一、LTE事件概述LTE切换时需要UE上报测量的结果（包括RSRP，RSRQ等），而上报又分为周期性上报和事件触发的上报。
周期性上报由基站配置，UE直接上报测量的结果。
事件触发的上报又分为系统内的事件和系统间的事件。
LTE系统内切换主要事件包括：A1事件，服务小区质量高于门限；这个事件可以用来关闭频间测量。
A2事件，服务小区质量低于门限；这个事件可以用来打开频间测量和系统间测量，因为这个事件发生后可能发生切换等操作。
A3事件，邻小区质量好于服务小区质量；这个事件一般用于频内/间基于覆盖的切换。
A4事件，邻小区质量好于门限；这个事件一般用于基于负荷的切换。
A5事件，服务小区质量低于一个门限并且邻小区质量高于一个门限；这个事件也可以用于频内/间基于覆盖的切换。
目前LTE同频切换都是基于A3/A5事件进行的切换（现网主要是基于A3事件的）二、切换流程举例- RRC Connection Reconfiguration（Measurement Control）测量控制，一般在初始接入或上一次切换命令中的重配消息里携带- Measurement Report测量报告，终端根据当前小区的测量控制信息，将符合切换门限的小区进行上报- HO Request源小区在收到测量报告后向目标小区申请资源及配置信息（站内切换的话为站内交互，站间切换会使用X2口或者S1口，优先使用X2口）- HO Request Ack目标小区将终端的接纳信息以及其它配置信息反馈给源小区- RRC Connection Reconfiguration（HO Command）将目标小区的接纳信息及配置信息发给终端，告知终端目标小区已准备好终端接入，重配消息里包含目标小区的测量控制- SN Status Transfer源小区将终端业务的缓存数据移至目标小区- Random Access Preamble终端收到第5步重配消息（切换命令）后使用重配消息里的接入信息进行接入- Random Access Response目标小区接入响应，收到此命令后可认为接入完成了，然后终端在RRC层上发重配完成消息（第9步）- RRC Connect Reconfiguration complete（HO Confirm）上报重配完成消息，切换完成- Release Resource当终端成功接入后，目标小区通知源小区删除终端的上下文信息四、协议对LTE事件的定义和说明4.1 A1事件定义Event A1 (Serving becomes better than threshold)The UE shall:1> consider the entering condition for this event to be satisfied when condition A1-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A1-2, as specifiedbelow, is fulfilled;1> for this measurement, consider the primary or secondary cell that is configured on the frequencyindicated in the associated measObjectEUTRA to be the serving cell;Inequality A1-1 (Entering condition)-Ms>HysThreshInequality A1-2 (Leaving condition)Ms<+ThreshHysThe variables in the formula are defined as follows:Ms is the measurement result of the serving cell, not taking into account any offsets.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigEUTRA for this event).Thresh is the threshold parameter for this event (i.e. a1-Threshold as defined within reportConfigEUTRA for this event).Ms is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Hys is expressed in dB.Thresh is expressed in the same unit as Ms.4.2 A2事件定义Event A2 (Serving becomes worse than threshold)The UE shall:1> consider the entering condition for this event to be satisfied when condition A2-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A2-2, as specifiedbelow, is fulfilled;1> for this measurement, consider the primary or secondary cell that is configured on the frequencyindicated in the associated measObjectEUTRA to be the serving cell;Inequality A2-1 (Entering condition)+Ms<HysThreshInequality A2-2 (Leaving condition)Ms>-HysThreshThe variables in the formula are defined as follows:Ms is the measurement result of the serving cell, not taking into account any offsets.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigEUTRA for this event).Thresh is the threshold parameter for this event (i.e. a2-Threshold as defined within reportConfigEUTRA for this event).Ms is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Hys is expressed in dB.Thresh is expressed in the same unit as Ms.4.3 A3事件定义Event A3 (Neighbour becomes offset better than PCell)The UE shall:1> consider the entering condition for this event to be satisfied when condition A3-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A3-2, as specifiedbelow, is fulfilled;NOTE The cell(s) that triggers the event is on the frequency indicated in the associated measObject which may be different from the (primary) frequency used by the PCell.Inequality A3-1 (Entering condition)++>+Mn++-OcnOfpOcpMpHysOffOfnInequality A3-2 (Leaving condition)++<Mn++++MpOcpOfnOfpOffHysOcnThe variables in the formula are defined as follows:Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ofn is the frequency specific offset of the frequency of the neighbour cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell).Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Mp is the measurement result of the PCell, not taking into account any offsets.Ofp is the frequency specific offset of the primary frequency (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the primary frequency).Ocp is the cell specific offset of the PCell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the primary frequency), and is set to zero if not configured for the PCell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Off is the offset parameter for this event (i.e. a3-Offset as defined within reportConfigEUTRA for this event).Mn, Mp are expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ofn, Ocn, Ofp, Ocp, Hys, Off are expressed in dB.4.4 A4事件定义Event A4 (Neighbour becomes better than threshold)The UE shall:1> consider the entering condition for this event to be satisfied when condition A4-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A4-2, as specifiedbelow, is fulfilled;Inequality A4-1 (Entering condition)-+Mn>+HysThreshOcnOfnInequality A4-2 (Leaving condition)Mn<+++ThreshOfnHysOcnThe variables in the formula are defined as follows:Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ofn is the frequency specific offset of the frequency of the neighbour cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell).Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigEUTRA for this event).Thresh is the threshold parameter for this event (i.e. a4-Threshold as defined within reportConfigEUTRA for this event).Mn is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ofn, Ocn, Hys are expressed in dB.Thresh is expressed in the same unit as Mn.4.5 A5事件定义Event A5 (PCell becomes worse than threshold1 and neighbour becomes better than threshold2)The UE shall:1> consider the entering condition for this event to be satisfied when both condition A5-1 andcondition A5-2, as specified below, are fulfilled;1> consider the leaving condition for this event to be satisfied when condition A5-3 or conditionA5-4, i.e. at least one of the two, as specified below, is fulfilled;NOTE: The cell(s) that triggers the event is on the frequency indicated in the associated measObject which may be different from the (primary) frequency used by the PCell.Inequality A5-1 (Entering condition 1)+Mp<HysThresh1Inequality A5-2 (Entering condition 2)+-+Mn>Thresh2HysOcnOfnInequality A5-3 (Leaving condition 1)-Mp>HysThresh1Inequality A5-4 (Leaving condition 2)2++Mn<+OfnHysThreshOcnThe variables in the formula are defined as follows:Mp is the measurement result of the PCell, not taking into account any offsets.Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ofn is the frequency specific offset of the frequency of the neighbour cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell).Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigEUTRA for this event).Thresh1 is the threshold parameter for this event (i.e. a5-Threshold1 as defined within reportConfigEUTRA for this event).Thresh2 is the threshold parameter for this event (i.e. a5-Threshold2 as defined within reportConfigEUTRA for this event).Mn, Mp are expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ofn, Ocn, Hys are expressed in dB.Thresh1is expressed in the same unit as Mp.Thresh2is expressed in the same unit as Mn.Event A6 (Neighbour becomes offset better than SCell)The UE shall:1> consider the entering condition for this event to be satisfied when condition A6-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A6-2, as specifiedbelow, is fulfilled;1> for this measurement, consider the (secondary) cell that is configured on the frequency indicatedin the associated measObjectEUTRA to be the serving cell;NOTE: The neighbour(s) is on the same frequency as the SCell i.e. both are on the frequency indicated in the associated measObject.Inequality A6-1 (Entering condition)+>Mn++-MsOcsOffHysOcnInequality A6-2 (Leaving condition)+<+Mn++OcsOffMsHysOcnThe variables in the formula are defined as follows:Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Ms is the measurement result of the serving cell, not taking into account any offsets.Ocs is the cell specific offset of the serving cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the serving frequency), and is set to zero if not configured for the serving cell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Off is the offset parameter for this event (i.e. a6-Offset as defined within reportConfigEUTRA for this event).Mn, Ms are expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ocn, Ocs, Hys, Off are expressed in dB.Event B1 (Inter RAT neighbour becomes better than threshold)The UE shall:1> for UTRA and CDMA2000, only trigger the event for cells included in the correspondingmeasurement object;1> consider the entering condition for this event to be satisfied when condition B1-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition B1-2, as specifiedbelow, is fulfilled;Inequality B1-1 (Entering condition)Thresh+Mn>-HysOfnInequality B1-2 (Leaving condition)++Mn<ThreshHysOfnThe variables in the formula are defined as follows:Mn is the measurement result of the inter-RAT neighbour cell, not taking into account any offsets.For CDMA 2000 measurement result, pilotStrength is divided by -2.Ofn is the frequency specific offset of the frequency of the inter-RAT neighbour cell (i.e. offsetFreq as defined within the measObject corresponding to the frequency of the neighbour inter-RAT cell).Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigInterRAT for this event).Thresh is the threshold parameter for this event (i.e. b1-Threshold as defined within reportConfigInterRAT for this event). For CDMA2000, b1-Threshold is divided by -2.Mn is expressed in dBm or in dB, depending on the measurement quantity of the inter-RAT neighbour cell.Ofn, Hys are expressed in dB.Thresh is expressed in the same unit as Mn.4.8 B2事件定义Event B2 (PCell becomes worse than threshold1 and inter RAT neighbour becomes better than threshold2)The UE shall:1> for UTRA and CDMA2000, only trigger the event for cells included in the correspondingmeasurement object;1> consider the entering condition for this event to be satisfied when both condition B2-1 andcondition B2-2, as specified below, are fulfilled;1> consider the leaving condition for this event to be satisfied when condition B2-3 or conditionB2-4, i.e. at least one of the two, as specified below, is fulfilled;Inequality B2-1 (Entering condition 1)+HysMp<Thresh1Inequality B2-2 (Entering condition 2)-+Mn>Ofn2ThreshHysInequality B2-3 (Leaving condition 1)Hys-Mp>1ThreshInequality B2-4 (Leaving condition 2)Mn<++OfnHys2ThreshThe variables in the formula are defined as follows:Mp is the measurement result of the PCell, not taking into account any offsets.Mn is the measurement result of the inter-RAT neighbour cell, not taking into account any offsets.For CDMA2000 measurement result, pilotStrength is divided by -2.Ofn is the frequency specific offset of the frequency of the inter-RAT neighbour cell (i.e. offsetFreq as defined within the measObject corresponding to the frequency of the inter-RAT neighbourcell).Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigInterRAT for this event).Thresh1 is the threshold parameter for this event (i.e. b2-Threshold1 as defined within reportConfigInterRAT for this event).Thresh2 is the threshold parameter for this event (i.e. b2-Threshold2 as defined within reportConfigInterRAT for this event). For CDMA2000, b2-Threshold2 is divided by -2.Mp is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Mn is expressed in dBm or dB, depending on the measurement quantity of the inter-RAT neighbour cell.Ofn, Hys are expressed in dB.Thresh1is expressed in the same unit as Mp.Thresh2is expressed in the same unit as Mn.第11页。
LTE切换时需要UE上报测量的结果（包括RSRP，RSRQ等），而上报又分为周期性上报和事件触发的上报。
周期性上报由基站配置，UE直接上报测量的结果。
事件触发的上报又分为同频系统的事件和不同系统间的事件：同频切换报告事件包括：
1. 事件A1，服务小区好于绝对门限；这个事件可以用来关闭某些小区间的测量。
2. 事件A2，服务小区差于绝对门限；这个事件可以用来开启某些小区间的测量，因为这个事件发生后可能发生切换等操作。
3. 事件A3，邻居小区好于服务小区；这个事件发生可以用来决定UE是否切换到邻居小区。
4. 事件A4，邻居小区好于绝对门限；
5. 事件A5，服务小区差于一个绝对门限并且邻居小区好于一个绝对门限；这个事件也可以用来支持切换
Event B1(Inter RAT neighbour becomes better than threshold)：表示异系统邻区质量高于一定门限，满足此条件事件被上报时，源eNodeB启动异系统切换请求；类似于UMTS的3C事件。
Event B2(Serving becomes worse than threshold1 and inter RAT neighbour becomes better than threshold2)：表示服务小区质量低于一定门限并且异系统邻区质量高于一定门限，类似于UMTS的3A事件。
LTE系统事件简介LTE系统事件简介一、LTE事件概述LTE切换时需要UE上报测量的结果（包括RSRP，RSRQ等），而上报又分为周期性上报和事件触发的上报。
周期性上报由基站配置，UE直接上报测量的结果。
事件触发的上报又分为系统内的事件和系统间的事件。
LTE系统内切换主要事件包括：A1事件，服务小区质量高于门限；这个事件可以用来关闭频间测量。
A2事件，服务小区质量低于门限；这个事件可以用来打开频间测量和系统间测量，因为这个事件发生后可能发生切换等操作。
A3事件，邻小区质量好于服务小区质量；这个事件一般用于频内/间基于覆盖的切换。
A4事件，邻小区质量好于门限；这个事件一般用于基于负荷的切换。
A5事件，服务小区质量低于一个门限并且邻小区质量高于一个门限；这个事件也可以用于频内/间基于覆盖的切换。
目前LTE同频切换都是基于A3/A5事件进行的切换（现网主要是基于A3事件的）二、切换流程举例三、切换流程简要说明- RRC Connection Reconfiguration（Measurement Control）测量控制，一般在初始接入或上一次切换命令中的重配消息里携带- Measurement Report测量报告，终端根据当前小区的测量控制信息，将符合切换门限的小区进行上报- HO Request源小区在收到测量报告后向目标小区申请资源及配置信息（站内切换的话为站内交互，站间切换会使用X2口或者S1口，优先使用X2口）- HO Request Ack目标小区将终端的接纳信息以及其它配置信息反馈给源小区- RRC Connection Reconfiguration（HO Command）将目标小区的接纳信息及配置信息发给终端，告知终端目标小区已准备好终端接入，重配消息里包含目标小区的测量控制- SN Status Transfer源小区将终端业务的缓存数据移至目标小区- Random Access Preamble终端收到第5步重配消息（切换命令）后使用重配消息里的接入信息进行接入- Random Access Response目标小区接入响应，收到此命令后可认为接入完成了，然后终端在RRC层上发重配完成消息（第9步）- RRC Connect Reconfiguration complete（HO Confirm）上报重配完成消息，切换完成- Release Resource当终端成功接入后，目标小区通知源小区删除终端的上下文信息四、协议对LTE事件的定义和说明4.1 A1事件定义Event A1 (Serving becomes better than threshold)The UE shall:1> consider the entering condition for this event to be satisfied when condition A1-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A1-2, as specifiedbelow, is fulfilled;1> for this measurement, consider the primary or secondary cell that is configured on the frequencyindicated in the associated measObjectEUTRA to be the serving cell;Inequality A1-1 (Entering condition)-Ms>HysThreshInequality A1-2 (Leaving condition)Ms<+ThreshHysThe variables in the formula are defined as follows:Ms is the measurement result of the serving cell, not taking into account any offsets.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Thresh is the threshold parameter for this event (i.e. a1-Threshold as defined within reportConfigEUTRA for this event).Ms is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Hys is expressed in dB.Thresh is expressed in the same unit as Ms.4.2 A2事件定义Event A2 (Serving becomes worse than threshold)The UE shall:1> consider the entering condition for this event to be satisfied when condition A2-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A2-2, as specifiedbelow, is fulfilled;1> for this measurement, consider the primary or secondary cell that is configured on the frequencyindicated in the associated measObjectEUTRA to be the serving cell;Inequality A2-1 (Entering condition)+Ms<HysThreshInequality A2-2 (Leaving condition)Ms>-HysThreshThe variables in the formula are defined as follows:Ms is the measurement result of the serving cell, not taking into account any offsets.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Thresh is the threshold parameter for this event (i.e. a2-Threshold as defined within reportConfigEUTRA for this event).Ms is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Hys is expressed in dB.Thresh is expressed in the same unit as Ms.4.3 A3事件定义Event A3 (Neighbour becomes offset better than PCell)The UE shall:1> consider the entering condition for this event to be satisfied when condition A3-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A3-2, as specifiedbelow, is fulfilled;NOTE The cell(s) that triggers the event is on the frequency indicated in the associated measObject which may be different from the (primary) frequency used by the PCell.Inequality A3-1 (Entering condition)++>+Mn++-OcnOfpOcpMpHysOffOfnInequality A3-2 (Leaving condition)++<Mn++++MpOcpOfnOfpOffHysOcnThe variables in the formula are defined as follows:Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ofn is the frequency specific offset of the frequency of the neighbour cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell).Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Mp is the measurement result of the PCell, not taking into account any offsets.Ofp is the frequency specific offset of the primary frequency (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the primary frequency).Ocp is the cell specific offset of the PCell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the primary frequency), and is set to zero if not configured for the PCell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Off is the offset parameter for this event (i.e. a3-Offset as defined within reportConfigEUTRA for this event).Mn, Mp are expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ofn, Ocn, Ofp, Ocp, Hys, Off are expressed in dB.4.4 A4事件定义Event A4 (Neighbour becomes better than threshold)The UE shall:1> consider the entering condition for this event to be satisfied when condition A4-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A4-2, as specifiedbelow, is fulfilled;Inequality A4-1 (Entering condition)-+Mn>+HysThreshOcnOfnInequality A4-2 (Leaving condition)Mn<+++ThreshOfnHysOcnThe variables in the formula are defined as follows:Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ofn is the frequency specific offset of the frequency of the neighbour cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell).Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Thresh is the threshold parameter for this event (i.e. a4-Threshold as defined within reportConfigEUTRA for this event).Mn is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ofn, Ocn, Hys are expressed in dB.Thresh is expressed in the same unit as Mn.4.5 A5事件定义Event A5 (PCell becomes worse than threshold1 and neighbour becomes better than threshold2)The UE shall:1> consider the entering condition for this event to be satisfied when both condition A5-1 andcondition A5-2, as specified below, are fulfilled;1> consider the leaving condition for this event to be satisfied when condition A5-3 or condition A5-4, i.e. at least one of the two, as specified below, is fulfilled;NOTE: The cell(s) that triggers the event is on the frequency indicated in the associatedmeasObject which may be different from the (primary) frequency used by the PCell.Inequality A5-1 (Entering condition 1)1Thresh Hys Mp <+Inequality A5-2 (Entering condition 2)2Thresh Hys Ocn Ofn Mn >-++Inequality A5-3 (Leaving condition 1)1Thresh Hys Mp >-Inequality A5-4 (Leaving condition 2)2Thresh Hys Ocn Ofn Mn <+++The variables in the formula are defined as follows:Mp is the measurement result of the PCell, not taking into account any offsets.Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ofn is the frequency specific offset of the frequency of the neighbour cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell).Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Thresh1 is the threshold parameter for this event (i.e. a5-Threshold1 as defined within reportConfigEUTRA for this event).Thresh2 is the threshold parameter for this event (i.e. a5-Threshold2 as defined within reportConfigEUTRA for this event).Mn, Mp are expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ofn, Ocn, Hys are expressed in dB.Thresh1 is expressed in the same unit as Mp .Thresh2 is expressed in the same unit as Mn .Event A6 (Neighbour becomes offset better than SCell)The UE shall:1> consider the entering condition for this event to be satisfied when condition A6-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition A6-2, as specifiedbelow, is fulfilled;1> for this measurement, consider the (secondary) cell that is configured on the frequency indicatedin the associated measObjectEUTRA to be the serving cell;NOTE: The neighbour(s) is on the same frequency as the SCell i.e. both are on the frequency indicated in the associated measObject.Inequality A6-1 (Entering condition)+>Mn++-MsOcsOffHysOcnInequality A6-2 (Leaving condition)+<+Mn++OcsOffMsHysOcnThe variables in the formula are defined as follows:Mn is the measurement result of the neighbouring cell, not taking into account any offsets.Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell.Ms is the measurement result of the serving cell, not taking into account any offsets.Ocs is the cell specific offset of the serving cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the serving frequency), and is set to zero if not configured for the serving cell.Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event).Off is the offset parameter for this event (i.e. a6-Offset as defined within reportConfigEUTRA for this event).Mn, Ms are expressed in dBm in case of RSRP, or in dB in case of RSRQ.Ocn, Ocs, Hys, Off are expressed in dB.Event B1 (Inter RAT neighbour becomes better than threshold)The UE shall:1> for UTRA and CDMA2000, only trigger the event for cells included in the correspondingmeasurement object;1> consider the entering condition for this event to be satisfied when condition B1-1, as specifiedbelow, is fulfilled;1> consider the leaving condition for this event to be satisfied when condition B1-2, as specifiedbelow, is fulfilled;Inequality B1-1 (Entering condition)Thresh+Mn>-HysOfnInequality B1-2 (Leaving condition)++Mn<ThreshHysOfnThe variables in the formula are defined as follows:Mn is the measurement result of the inter-RAT neighbour cell, not taking into account any offsets.For CDMA 2000 measurement result, pilotStrength is divided by -2.Ofn is the frequency specific offset of the frequency of theinter-RAT neighbour cell (i.e. offsetFreq as defined within the measObject corresponding to the frequency of the neighbour inter-RAT cell).Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigInterRAT for this event).Thresh is the threshold parameter for this event (i.e. b1-Threshold as defined within reportConfigInterRAT for this event). For CDMA2000, b1-Threshold is divided by -2.Mn is expressed in dBm or in dB, depending on the measurement quantity of the inter-RAT neighbour cell.Ofn, Hys are expressed in dB.Thresh is expressed in the same unit as Mn.4.8 B2事件定义Event B2 (PCell becomes worse than threshold1 and inter RAT neighbour becomes better than threshold2)The UE shall:1> for UTRA and CDMA2000, only trigger the event for cells included in the correspondingmeasurement object;1> consider the entering condition for this event to be satisfied when both condition B2-1 andcondition B2-2, as specified below, are fulfilled;1> consider the leaving condition for this event to be satisfied when condition B2-3 or conditionB2-4, i.e. at least one of the two, as specified below, is fulfilled;Inequality B2-1 (Entering condition 1)+HysMp<Thresh1Inequality B2-2 (Entering condition 2)-+Mn>Ofn2ThreshHysInequality B2-3 (Leaving condition 1)Hys-Mp>1ThreshInequality B2-4 (Leaving condition 2)Mn<++OfnHys2ThreshThe variables in the formula are defined as follows:Mp is the measurement result of the PCell, not taking into account any offsets.Mn is the measurement result of the inter-RAT neighbour cell, not taking into account any offsets.For CDMA2000 measurement result, pilotStrength is dividedby -2.Ofn is the frequency specific offset of the frequency of the inter-RAT neighbour cell (i.e. offsetFreq as defined within the measObject corresponding to the frequency of the inter-RAT neighbourcell).Hys is the hysteresis parameter for this event (i.e. hysteresis as defined withinreportConfigInterRAT for this event).Thresh1 is the threshold parameter for this event (i.e. b2-Threshold1 as defined within reportConfigInterRAT for this event).Thresh2 is the threshold parameter for this event (i.e. b2-Threshold2 as defined within reportConfigInterRAT for this event). For CDMA2000, b2-Threshold2 is divided by -2.Mp is expressed in dBm in case of RSRP, or in dB in case of RSRQ.Mn is expressed in dBm or dB, depending on the measurement quantity of the inter-RAT neighbour cell.Ofn, Hys are expressed in dB.Thresh1 is expressed in the same unit as Mp. Thresh2 is expressed in the same unit as Mn.。
LTE支持的切换事件有A类和B类两种，其中A类事件被用作系统内的测量，B类事件被用作系统间的测量;
A事件和B事件一般是基于覆盖的测量控制和判决事件，
A1测量停止事件，A2测量启动事件，A3同频测量控制/判决事件，A4异频测量判决事件，
B1/B2异系统启动和判决事件。
这个是指测量事件，详细可参考3GPP 36.331，当网络信号强度满足一定条件时，终端上报相关的事件报告给网络
同系统测量事件：
A1事件：表示服务小区信号质量高于一定门限；用于关闭正在进行的频间测量和去激活Gap。
A2事件：表示服务小区信号质量低于一定门限；用于打开频间测量和激活Gap。
A3事件：表示邻区质量高于服务小区质量，且大于偏置值，用于同频、异频的基于覆盖的切换；
A4事件：表示邻区质量高于一定门限，用于基于负荷的切换，可用于负载均衡；
A5事件：表示邻区质量高于一定门限并且服务小区质量低于一定门限，可用于负载均衡;
异系统测量事件：
B1事件：邻小区质量高于一定门限，用于测量高优先
级的异系统小区；
B2事件：邻小区质量高于一定门限并且服务小区质量低于一定门限，用于相同或较低优先级的异系统小区的测量。
LTE支持的切换事件有A类和B类，其中A类本用作系统内测量，B类被用作系统间测量A1事件：表示服务小区信号质量高于一定门限；A2事件：表示服务小区信号质量低于一定门限；A3事件：表示邻区质量高于服务小区质量，用于同频、异频的基于覆盖的切换；A4事件：表示邻区质量高于一定门限，用于基于负荷的切换，可用于负载均衡；A5事件：表示服务小区质量低于一定门限并且邻区质量高于一定门限，可用于;异系统测量事件：B1事件：邻小区质量高于一定门限，用于测量高的异系统小区；B2事件：服务小区质量低于一定门限，并且邻小区质量高于一定门限，用于相同或较低优先级的异系统小区的测量。
LTE移动性参数(全局)最小接入电平基本信息参数功能该参数表示UE在该小区驻留需满足的最小接收电平门限。
该值取值范围是2G/3G接收电平的实际值，对于LTE/3G,?实际的RxlevMin?等于SIB3/SIB6的IEvalue的两倍，调整步长为2dbm。
对于2G，实际的RxlevMin等于SIB7的?(IEvalue*2)? ?115，调整步长为2dBm当UE测量到的2G/3G电平满足S准则时，UE才可能驻留在该小区。
参数调整影响调整该参数的门限值，会对小区的选择和驻留有所影响。
QrxLevMin如果设置过高，则UE将无法驻留到该小区。
高优先级重选门限基本信息参数功能当高优先级小区的S值在一定时间内高于该阀值(threshXHigh)后，UE可以重选到该小区。
参数调整影响调整该参数的门限值，会对小区的选择和驻留有所影响。
threshXhigh如果设置过高，?会增加UE重选到高优先级小区的难度。
低优先级重选门限基本信息参数功能当低优先级小区的S值在一定时间内高于该阀值(threshXLow)后，同时主服务小区的S值低于threshServingLow，UE可以重选到该低优先级小区。
参数调整影响调整该参数的门限值，会对小区的选择和驻留有所影响。
threshXLow如果设置过高，?会增加UE 重选到低优先级小区的难度。
LTE支持的切换事件有A类和B类，其中A类本用作系统内测量，B类被用作系统间测量A1事件：表示服务小区信号质量高于一定门限；A2事件：表示服务小区信号质量低于一定门限；A3事件：表示邻区质量高于服务小区质量，用于同频、异频的基于覆盖的切换；A4事件：表示邻区质量高于一定门限，用于基于负荷的切换，可用于负载均衡；A5事件：表示服务小区质量低于一定门限并且邻区质量高于一定门限，可用于负载均衡; 异系统测量事件：B1事件：邻小区质量高于一定门限，用于测量高优先级的异系统小区；B2事件：服务小区质量低于一定门限，并且邻小区质量高于一定门限，用于相同或较低优先级的异系统小区的测量。
LTE移动性参数(全局)1最小接入电平基本信息参数名称(中文)参数名称(英文)取值范围单位最小接收电平QrxLevMin LTE (-140 (44)3G (-119 (25)2G (-115 (25)dBm缺省值开局建议值配置步长参数类型LTE:-1403G邻区频点:-119 2G邻区频点:-115LTE:-1223G:-1192G:-1152长整型影响范围修改生效方式参数出处适用制式LTE小区2G/3G邻区频点修改立即生效3GPP TS 36.331通用参数功能该参数表示UE在该小区驻留需满足的最小接收电平门限。
该值取值范围是2G/3G接收电平的实际值，对于LTE/3G , 实际的RxlevMin 等于SIB3/SIB6的IE value的两倍，调整步长为2dbm。
对于2G，实际的RxlevMin等于SIB7的 (IE value * 2) 115，调整步长为2dBm当UE测量到的2G/3G电平满足S准则时，UE才可能驻留在该小区。
参数调整影响调整该参数的门限值，会对小区的选择和驻留有所影响。
QrxLevMin如果设置过高，则UE将无法驻留到该小区。
2高优先级重选门限基本信息参数功能当高优先级小区的S值在一定时间内高于该阀值(threshXHigh)后，UE可以重选到该小区。
1 4.5.1 切换正常流程同频切换同时支持同eNodeB切换，同MME的异eNodeB切换，跨MME的异eNodeB切换场景。
对于后两种场景依据eNodeB间是否建立X2接口，切换信令流程略有不同。
图4-2 同MME异eNodeB间切换流程同MME异eNodeB间的同频切换信令流程如图4-2所示：1.在无线承载建立时，源eNodeB下发RRC Connection Reconfiguration至UE，其中包含source eNodeB 配置的Measurement Configuration消息，用于控制UE连接态的测量过程。
2.UE根据测量结果上报Measurement Report。
3.源eNodeB根据测量报告进行切换决策。
4.当源eNodeB决定切换后，源eNodeB发出HandoverRequest消息给目标eNodeB，通知目标eNodeB准备切换。
5.目标eNodeB进行准入判断，若判断为资源准入，再由目标eNodeB依据EPS的QoS信息执行准入控制。
6.目标eNodeB在L1/L2准备切换并对源eNodeB发送HANDOVER REQUESTACKNOWLEDGE消息。
3.1.2 报告配置事件触发上报是3GPP 36.331协议中为切换测量与判决定义的一个概念。
报告配置包含相应事件的相关参数。
目前eNodeB应用以下事件触发相应动作：●事件A1表示服务小区质量高于一定门限，当满足事件触发条件时UE便上报测量报告，eNodeB 停止异频/异系统测量。
但在基于频率优先级的切换中，事件A1用于启动异频测量。
●事件A2表示服务小区质量低于一定门限，当满足事件触发条件时UE便上报测量报告，eNodeB 启动异频/异系统测量。
但在基于频率优先级的切换中，事件A2用于停止异频测量。
●事件A3表示同频/异频邻区质量相比服务小区质量高出一定门限，当满足事件触发条件的小区信息被上报时，源eNodeB启动同频/异频切换请求。
●事件A4表示异频邻区质量高于一定门限，满足事件触发条件的小区信息被上报时，源eNodeB 启动异频切换请求。
●事件A5表示服务小区质量低于一定门限，同时异频邻区质量高于一定门限，满足事件触发条件的小区信息被上报时，源eNodeB启动异频切换请求。
●事件B1表示异系统邻区质量高于一定门限，满足事件触发条件的小区信息被上报时，源eNodeB启动异系统切换请求。
●事件B2表示服务小区质量低于一定门限，同时异系统邻区质量高于一定门限，满足事件触发条件的小区信息被上报时，源eNodeB启动异系统切换请求。
事件转周期上报事件被触发并上报之后将转为周期上报满足该事件的测量信息，此方式称为事件转周期上报。
UE的测量结果通过事件转周期的方式上报给eNodeB。
周期上报将在事件取消条件满足或达到最大上报次数或UE收到切换命令后后取消。
事件转周期上报方式有如下作用：●可有效防止因测量报告的遗失或内部处理流程的失败对切换造成影响。
●对于准入拒绝，可以起到重试的作用。
●测量报告中，邻区可能一次报不完。
并且随着UE的移动，会上报不同的邻区，通过事件转周期可以得到比较完整的测量结果。
4.2.2 事件A3的触发（LST INTRAFREQHOGROUP）同频切换通过事件A3触发，且事件上报方式采用事件转周期的上报方式。
事件A3的触发，即邻区质量高于服务小区一定偏置值。
参照3GPP协议36.331规定事件A3的判决公式。
触发条件：Mn+Ofn+Ocn-Hys>Ms+Ofs+Ocs+Off公式中的变量有如下定义：●Mn是邻区测量结果。
●Ofn是邻区频率的特定频率偏置，由参数QoffsetFreq决定，此参数在测量控制消息的测量对象中下发。
●Ocn是邻区的特定小区偏置，由参数CellIndividualOffset决定。
当该值不为零，此参数在测量控制消息中下发；否则当该值为零时不下发，公式计算时默认取值为0。
eNodeB将根据小区负载情况临时修改邻区与服务小区的CIO，触发基于负载的同频切换。
●Ms是服务小区的测量结果。
●Ofs是服务小区的特定频率偏置，由参数QoffsetFreq决定，此参数在测量控制消息的测量对象中下发。
●Ocs是服务小区的特定小区偏置，由参数CellSpecificOffset决定。
此参数在测量控制消息中下发。
●Hys是事件A3迟滞参数，由参数IntraFreqHoA3Hyst决定，在测量控制消息中下发。
●Off是事件A3偏置参数，由参数IntraFreqHoA3Offset决定。
该参数针对事件A3设置，用于调节切换的难易程度，该值与测量值相加用于事件触发和取消的评估。
此参数在测量控制消息的测量对象中下发，可取正值或负值，当取正值时，此时增加事件触发的难度，延缓切换；当取负值时，此时降低事件触发的难度，提前进行切换。
事件A2触发异频测量（LST INTERFREQHOGROUP）在基于覆盖的异频切换中，事件A2用于异频测量的触发，表示服务小区的质量已经低于一定门限值。
当事件A2满足上报条件并上报eNodeB后，将触发异频测量配置的下发。
3GPP TS 36.331中，事件A2的判决公式如下。
触发条件：Ms+Hys<Thresh公式中的变量由如下定义：●Ms是服务小区的测量结果。
●Hys是事件A2迟滞参数，由参数InterFreqHoA1A2Hyst决定。
事件A1停止异频测量在基于覆盖的异频切换中，事件A1用于停止异频测量，表示服务小区的质量已经高于一定门限值。
当事件A1满足上报条件并上报eNodeB后，将触发异频测量的停止。
3GPP协议36.331中事件A1的判决公式如下。
触发条件：Ms-Hys>Thresh公式中的变量由如下定义：●Ms是服务小区的测量结果。
●Hys是事件A1迟滞参数，由参数InterFreqHoA1A2Hyst决定。
事件A4的触发事件A4的触发，即邻区质量高于一定门限值。
参照3GPP协议36.331规定的事件A4判决公式如下。
触发条件：Mn+Ofn+Ocn-Hys>Thresh公式中的变量有如下定义：●Mn是邻区测量结果。
●Ofn是邻区频率的特定频率偏置，由参数QoffsetFreq决定，此参数在测量控制消息的测量对象中下发。
●Ocn是邻区的特定小区偏置，由参数CellIndividualOffset决定。
当该值不为零，此参数在测量控制消息中下发；否则当该值为零时不下发，公式计算时默认取值为0。
●Hys是事件A4迟滞参数，由参数InterFreqHoA4Hyst决定，在测量控制消息中下发。
●事件A4的时间迟滞由参数InterFreqHoA4TimeToTrig设置。
邻区质量在Time to Trigger （InterFreqHoA4TimeToTrig）的时间内一直高于任一门限值，并满足事件的上报条件，将上报事件A4。
3.3.3 切换失败后的RRC连接重建当切换失败后，UE将自动进行RRC连接重建：UE先进行小区选择，再对所选小区发起RRC连接重建过程。
eNodeB通过判断是否有该UE的context，对发起RRC连接重建请求的UE进行重建判决。
若UE获得eNodeB侧准许消息，UE将接入所选择小区，有效减少由于切换失败而带来的掉话。
按照3GPP协议36.331，只有prepared cell才可能有该UE的上下文，prepared cell所属的eNodeB通过判断该UE上下文内容，准许UE的RRC 连接重建请求，其他小区对其RRC连接重建请求进行拒绝。
5.3.1 RRC连接重建触发条件UE在如下几种情况会触发RRC连接重建：●检测到无线链路失败●切换失败●从E-UTRAN向异系统网络切换失败时●从底层收到了完整性检查失败指示●RRC连接重配置失败在满足如下任一条件时，UE认为检测到无线链路失败：●定时器T310超时●随机接入失败且定时器T300、T301、T304（T304ForEutran、T304ForGeran）或者T311都未运行时●RLC达到最大重传次数RRC连接重建成功后，SRB1可以被恢复，其他无线承载不进行恢复。
eNodeB处理RRC连接重建将会重配置SRB1，并重新开始此无线承载上的数据传输。
定时器310定时器300系统内切换T304定时器1 定时器3115.3.2 RRC连接重建流程RRC连接重建过程如图5-4所示。
图5-4 RRC连接重建流程图步骤1UE发送RRC Connection Reestablishment Request消息。
根据不同的场景，消息中携带的重建原因与小区信息不同。
−重配置失败触发的重建原因为“reconfigurationFailure”，其中的C-RNTI和physCellId 为本小区信息。
−切换失败触发的重建原因为“handoverFailure”，其中的C-RNTI和physCellId为源小区的信息。
−无线链路失败触发的重建原因为“otherFailure”，其中的C-RNTI和physCellId为本小区信息。
步骤2eNodeB进行安全参数认证，如果UE的安全参数认证信息与eNodeB的一致，则UE认证通过。
UE身份认证后，eNodeB将原资源释放，重新进行准入和资源分配。
如果UE认证不通过，则eNodeB拒绝该UE这次的RRC连接重建请求。
步骤3eNodeB在CCCH信道上向UE发送RRC Connection Reestablishment消息，消息中携带新分配资源的信息。
UE收到RRC Connection Reestablishment消息，根据消息指示重新配置无线资源，激活加密和完整性保护。
步骤4UE发送RRC Connection Reestablishment Complete消息给eNodeB。
3.2 小区选择与重选当UE选择了一个PLMN之后，就会在该PLMN中选择一个小区驻留。
UE在该小区驻留后，通过监听系统消息，根据邻区测量规则和小区重选规则，对当前小区以及邻区进行测量，选择一个信号质量更好的小区进行驻留。
小区选择与小区重选流程如图3-2所示，小区选择可以采用Stored Information Cell Selection和Initial Cell Selection两种方式，先采用Stored Information Cell Selection选择小区，如果搜索不到suitable cell时，则启用Initial Cell Selection进行小区选择。
详细请参见3GPP TS 36.304。
图3-2 小区选择与小区重选流程图3.2.2 小区选择当UE从连接态转移到空闲态时，或当UE选择一个PLMN后，都需要进行小区选择，选择一个小区驻留。
