LTE中各事件定义与应用
LTE常见事件解释及定时器
1.1 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。
1.2 报告配置(A1至A5 B1至B2)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 A1-A5 B1-B2事件
LTE支持的切换事件有A类和B类，其中A类被用作系统内测量，B类被用作系统间测量B1：邻小区比绝对门限好。
用于测量高优先级的RAT小区B2：服务小区比绝对门限1差，邻小区比绝对门限2好，用于相同或者低优先级的RAT 小区的测量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是否切换到邻区4. 事件A4，邻区好于绝对门限；5. 事件A5，服务小区差于一个绝对门限并且邻区好于一个绝对门限；这个事件也可以用来支持切换Intra-Frequency-HO切换都是基于A3/A5事件进行的切换A3事件：邻区的服务质量（RSRP/RSRQ）比服务小区高一个绝对门限，触发A3事件切换。
A5事件：服务小区的服务质量低于一个绝对门限1，邻区的服务质量高于一个绝对门限2，触发A5事件切换。
1.A3或A5事件触发。
2.Source eNB 向UE发送mearsurement control 4q;d6C1[1m+_,M+N1j:l3.Source eNB 向UE发送UL allocation MSG4.UE向Source eNB发送Measurement report MSG5.Source eNB内部进行HO decision6.Source eNB向Target eNB发送Handover request MSG7.Target eNB内部进行Admission controlMSCBSC 移动通信论坛,x"w3Q)j'V8.Target eNB向Source eNB回复Handover request ack MSG 9.Source eNB向UE回复DL allocation MSG10.Source eNB向UE发送RRC Connection reconfiguration MSGMSCBSC 移动通信论坛.k)C1b7\)C+x7W(j11.UE与Source eNB进行Detach，并开始同步到Target eNB12.Source eNB进行缓存控制并向Target eNB传送数据包以及进行SN status transfer （序列数转移）13.Source eNB向Target eNB进行数据转移传送"T/`2L4F [:u*v14.UE与Target eNB同步完成MSCBSC 移动通信论坛$b1e3x3~"X G8A15.Target eNB向UE发送UL Allocation+TA UE MSG16.UE向Target eNB发送RRC connection complete MSG 17.UE与Target eNB，Target eNB与S-GW之间进行数据交互;Q:u5O&m)F1h18.Target eNB向MME发起Path switch request 19.MME向S-GW发起user plane update requestMSCBSC 移动通信论坛!w!P,U5c5}3T5y9H20.S-GW与Source eNB进行Switch DL Path，并发起End marker MSGmscbsc 移动通信论坛拥有30万通信专业人员，超过50万份GSM/3G等通信技术资料，是国内领先专注于通信技术和通信人生活的社区。
LTE常见事件以及解析
名称含义具体说明AttachAttempt 附着尝试UE发送Attach Request消息请求附着到数据业务。
AttachSuc 附着成功UE发送Attach Request消息后，在45秒内发送Attach Complete消息，表示附着数据业务成功。
AttachFail 附着失败UE发送Attach Request消息后，在45秒内未发送Attach Complete消息，表示附着数据业务失败。
DetachAttempt 去附着尝试UE发送Detach Request消息或基站发送Detach Request消息请求去附着到数据业务。
DetachSuc 去附着成功"以下情况表示UE去附着数据业务成功：UE向基站发送Detach Request消息后，在15秒内收到基站发出的Detach Accept消息。
基站向UE发送Detach Request消息后，在15秒内收到UE发出的Detach Accept消息" RRCSetupReq RRC（Radio Resource Control）连接建立请求UE 发送RRC Connection Request消息请求建立RRC连接。
RRCSetupSuc RRC连接建立成功MS发出RRC Connection Request，并且内UE发出RRC Connection Setup Complete，则触发该事件。
RRCSetupFail RRC连接建立失败MS发出RRC Connection Request，并且内UE没有发出RRC Connection Setup Complete，或者收到RRC Connection Reject，则触发该事件。
ERABSetupAttempt ERAB（Evolved Radio Access Bearer）建立尝试如果RRC Connection Reconfiguration消息中包含特定的信元（“drb-ToAddModList”或“drb-ToAddModifyList”），并且不包含信元“mobilityControlInfo”，表示ERAB建立尝试。
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 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.。
A1-B2事件
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。
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。
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。
3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。
LTE切换事件介绍
Ocn：邻小区个性偏移（CIO）
Hys(5)：A5事件迟滞参数 Thersh1:A5事件门限1参数 Thersh2:A5事件门限2参数
B1事件的切换参数配置
B1事件表示：异系统邻区质量高于一个绝对门限，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，用于基于负荷的切换 B1事件判决公式： 触发条件： Mn + Ofn - Hys(b1) > Thersh(b1) 取消条件：Mn + Ofn + Hys(b1) > Thersh(b1) 其中： Mn:邻小区测量结果 Ofn：邻小区频率特定的偏差，默认为0
根据A1事件触发条件：Ms – Hys(1) > Thersh(1）可以算出： Ms>-86时关闭异频测量。 根据A2事件触发条件：Ms + Hys(2) < Thersh(2) 可以算出： Ms<-92时开启异频测量 则当UE测量到的A小区RSRP值为红色区域时，UE不进行异频测量；当 UE测量到的A小区RSRP值为绿色区域时，UE进行异频测量；当UE测量到的A 小区RSRP值为黄色区域时，UE是否进行异频测量取决于UE之前的状态，即 UE的测量状态并不改变。
频内/频间基于覆盖的切换 B1事件：异系统邻区质量高于一个绝对门限，用于基于负荷的切换。
B2事件：服务小区质量低于一个绝对门限1且异系统邻区质量高于一个绝对门限2，
用于基于覆盖的切换。
A1事件的切换参数配置
A1事件触发条件：Ms – Hys(1) > Thersh(1） A1事件取消条件：Ms + Hys(2) < Thersh(2) 其中： Ms:服务小区测量结果 Hys(1)：A1事件迟滞参数 Hys(2)：A2事件迟滞参数 Thersh（1）:A1事件门限参数 Thersh（2）:A2事件门限参数
AB事件LTE
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。
移动LTE系统事件介绍
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。
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Ø Event A1 (Serving becomes better than threshold)：表示服务小区信号质量高于一定门限，满足此条件的事件被上报时，eNodeB停止异频/异系统测量；类似于UMTS里面的2F事件；
ØEvent A2 (Serving becomes worse than threshold)：表示服务小区信号质量低于一定门限，满足此条件的事件被上报时，eNodeB启动异频/异系统测量；类似于UMTS里面的2D事件；
ØEvent A3 (Neighbour becomes offset better than serving)：表示同频邻区质量高于服务小区质量，满足此条件的事件被上报时，源eNodeB启动同频切换请求；
ØEvent A4 (Neighbour becomes better than threshold)：表示异频邻区质量高于一定门限量，满足此条件的事件被上报时，源eNodeB启动异频切换请求；
ØEvent A5 (Serving becomes worse than threshold1 and neighbour becomes better than threshold2)：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；类似于UMTS里的2B事件；
ØEvent 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里的3C 事件；
ØEvent 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里进行异系统切换的3A事件。
从定义上就可以看出来，A5和B2的条件最苛刻，必须满足服务小区低于某绝对门限，同时邻区高于某绝对门限才会上报。
而A3只是邻区比服务小区强某个相对门限时就会上报。
A4和B1只对邻区作判断，A1和A2只是对服务小区作判断。
因为在实际应用中，A3通常用于同频切换。
原因是同频测量在任何时刻都可以进行，而异频和异系统测量需要配置GAP，在GAP周期内，只测量邻区，不测量服务小区。
不同的厂家有不同的算法，我了解的是同频用A3，如果上报A2，再配置A4或B1，如果上报了A4和B1，就会触发异频或异系统切换(或重定向），如果没上报A4或B1，上报了A1，就会删除A4和B1。
这个算法的原则就是，尽量简化UE的测量内容，先测同频，同频切换该切就切，如果在这种情况下服务小区变差，说明同频覆盖有问题，就要配置异频或异系统测量，配置GAP，如果服务小区变好了，就删除异频或异系统测量，取消GAP。