UECapabilityEnquiry The UECapabilityEnquiry message is used to request the transfer of UE radio access capabilities for E-UTRA as well as for other RATs. The UECapabilityInformation message is used to transfer of UE radio access capabilities requested by the E-UTRAN The UEInformationRequest is the command used by E-UTRAN to retrieve information from the UE. The UEInformationResponse message is used by the UE to transfer the information requested by the E-UTRAN. The ULHandoverPreparationTransfer message is used for the uplink transfer of handover related CDMA2000 information when requested by the higher layers. The DLInformationTransfer message is used for the downlink transfer of dedicated NAS information. The ULInformationTransfer message is used for the uplink transfer of dedicated NAS information. UECapabilityInformation UEInformationRequest UEInformationResponse ULHandoverPreparation Transfer (CDMA2000) (DLInformationTransfer) (ULInformationTransfer)
SRB2:承载NAS消息,映射到DCCH信道 消息名 DLInformationTransfer 消息含义 The DLInformationTransfer message is used for the downlink transfer of dedicated NAS information. The ULInformationTransfer message is used for the uplink transfer of dedicated NAS information. ULInformationTransfer
UE的RRC连接未建立时,由SRB0承载RRC信令;SRB2未建立时,由SRB1承载NAS信令 NAS消息其他承载方式
由于带宽增加,数据传输性能增强,LTE的RRC消息的数据携带能力显著提升;因此LTE中所有NAS消息可填充在RRC消息中携带传输,进一步精简了信令流程
NAS消息通过四条RRC消息传递:
ULInformationTransfer 和 DLInformationTransfer(由SRB2承载,SRB2未建立时由SRB1承载) RRCConnectionSetupComplete和
RRCConnectionReconfiguration(由SRB1承载)
RRCConnectionSetupComplete(只携带NAS的初始直传消息)
LTE业务总体流程
2、LTE信令流程介绍
系统消息
系统消息概述
? 系统信息在小区范围内的所有UE进行广播,目的是告诉UE网络接入层和非接入层的公共信息,以便用户在发起呼叫之前了解网络的配置情况
? 非接入层的信息包括运营商信息、CN域信息