目录

LTE(4G) - NR(5G) RRC连接重配置(RRC Connection Reconfiguration)

描述

RRC Connection Reconfiguration可传递信息

流程图

Log

总结

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LTE(4G) - NR(5G) RRC连接重配置(RRC Connection Reconfiguration)

描述

RRC连接重配置的主要功能是修改RRC连接。我们知道当UE第一次接入网络时，必须进行RRC连接和建立的原因是建立SRB1等承载。 如果UE需要传IP需要建立包DRB或者SRB他们是如何建立的？就是通过RRC连接重配置进行建立

RRC Connection Reconfiguration可传递信息

传递信息	案例
无线资源配置	包括DRB SRB等RB操作，MAC 主要配置和66道无线信配置
相关专用NAS信息和安全配置
修改控制信息	例如，发送切换命令UE要进入邻区，基站发送一个RRC连接重配置信令，UE会先建立一个DRB而后UE会发起一个重配置成功消息
测试配置	建立 , 修改 , 释放 , 测量 。如何测量，网络侧将通过自己的测量信息RRC重配置给UE的

流程图

过程很简单，基站发起了重配置，UE收到后，根据重配置协议信息进行配置，UE发起连接重配置的成功信函

Log

RRCConnectionReconfiguration Type: DCCH_DL Direction: Downlik Computer Timestamp: 14:33:22.943 Earfcn\Pci: 32432 - 55 DL - DCCH-Message  message   c1    rrcConnectionReconfiguration     rrc-TransactionIdentifier: 0      criticalExtensions      c1       rrcConnectionReconfiguration-r8        measConfig  //配置相应的测量，如何测量，如何测量，需要基站通知UE的         measObjectToAddModList          measObjectId: 2          measObjectId //测量对象           measObjectEUTRA            carrierFreq: 344213 ///测量目标频点            allowedMeasBandWidhth: (0)mbw6  //允许测量的带宽            presenceAntennaPrort1: false            neighCellConfig: 0x1  //配置邻区            offsetFreq: (15) dB0  //偏移量         reportConfigToAddModList            ReportConfigToAddMod           reportConfigId: 1           reportConfig   //            reportConfigEUTRA             triggerType              event               eventId                eventA3 //基于测量报告A3进行发送的                 a3-Offset: 6  //A3的偏移量                 reportOnLeave: false               hysteresis: 2               timeToTrigger: (1) ms40             triggerQuantity: (0) rerp             reportQuantity: (1) both             maxReportCells: 4  //最大上报社区             reportInterval: (2) ms480             reportAmount: (7) infinity           reportConfigId: 2           reportConfig            reportConfigEutra             triggerType              event               eventId                eventA2 //A2测试报告事件                 a2-Threshold                  threshold-RSRP: 0               hysteresis: 2               timeToTrigger: (11) ms661             triggerQuantity: (0) rsrp             reportQuantity: (1) both             maxReportCells: 5             reportInterval: (2) ms441             reportAmount:(7) infinity           reportConfigId: 3           reportConfig            reportConfigEUTRA             triggerType              event               eventId                eventA2                 a2-Threshold                  threshold-RSRQ: 1               hysteresis: 2               timeToTrigger: (11) ms642             triggerQuantity: (1) resrq             reportQuantity: (1) both             maxReportCells: 4             reportInterval: (2) ms480             reportAmount: (7) infinity         measIdToAddModList          MeasIdToAddMod           measId: 1           measObjectId: 1           reportConfigId :1           measId: 2           measObjectId: 1           reportConfigId: 2           measId: 3           measObjectId: 1           reportConfigId: 3         quantityConfig          quantityConfigEUTRA           filterCoefficentRSRP: (4) fc4
										filterCoefficientRSRQ: (5) fc11
									speedStatePars: release
							radioResourceConfigDedicated  //无线资源的专用配置
								srb-ToAddModList 
									SRB-ToAddMod
										srb-Identity: 2   //配置SRB2
										rlc-Config
											explicitValue
												am
													ul-AM-RLC
														t-PollRetransmit: (8) ms45
														pollPDU: (7) pInfinity
														pollByte: (14)kBinfinity
														maxRetxThreshold: (5) t8
													dl-AM-RLC
														t-Reordering: (7) ms35
														tStatusProhibit: (0) ms0
										logicalChannelConfig
											explicitValue
												ul-SpecificParameters
													priority: 3
													prioritisedBitRate: (7) infinity
													bucketSizeDuration: (0) ms50
													logicalChannelGroup: 0
								drb-ToAddModList
									DRB-ToAddMod
										eps-BearerIdentity:5  //EPS 承载
										drb-Identity: 3     //配置DRB
										pdcp-Config
											discardTimer: (7) infinity
											rlc-AM
												statusReportRequired: false
											headerCompression: notUsed
										rlc-Config
											am
												ul-AM-RLC
													t-PollRetransmit: (9) ms50
													pollPDU: (2) p13
													pollByte: (14) kBinfinity
													maxRetxThreshold: (5) t8
												dl-AM-RLC
													t-Reordering: (7) ms35
													t-StatusProhoibit: (5) ms25
										logicalChannelIdentity: 3
										logicalChannelConfig
											ul-SpecificParameters
												priority: 4
												prioritisedBitRate: (1) kBps8
												bucketSizeDuration: (0) ms50
												logicalChannelGroup: 1
												

总结

通过查看基站反馈的RRC Connection Reconfiguration后，UE会读取协议中的内容配置UE相关信息，比如建立SRB2,DRB,还有pdcp层配置等。