02LF_SP2001_C03_1LTE协议原理.pptVIP

接入层：RRC以下的都是接入层；RRC以上的都是非接入层。 无线网络层能理解的，都是接入层，不需要无线网络层解析的是非接入层消息。 接入层就是UE和核心网之间需要读懂的东西 * * * 对于TDD，同一个时刻，一个子帧要么分配给下行，要么分配给上行。 子帧0、5和DwPTS总是用于下行发送 支持5ms和10ms的切换周期 * ASN.1：ASN.1是一种 ISO/ITU-T 标准，描述了一种对数据进行表示、编码、传输和解码的数据格式。它提供了一整套正规的格式用于描述对象的结构，而不管语言上如何执行及这些数据的具体指代，也不用去管到底是什么样的应用程序。在任何需要以数字方式发送信息的地方，ASN.1 都可以发送各种形式的信息（声频、视频、数据等等）。ASN.1 和特定的 ASN.1 编码规则推进了结构化数据的传输，尤其是网络中应用程序之间的结构化数据传输，它以一种独立于计算机架构和语言的方式来描述数据结构。 AMC：自适应调制编码 * LTE中的HARQ技术采用增量冗余（Incremental Redundantcy，IR）HARQ,即通过第一次传输发送信息bit和一部分冗余bit，而通过重传（Retransmission）发送额外的冗余bit，如果第一次传输没有成功解码，则可以通过重传更多冗余bit降低信道编码率，从而实现更高的解码成功率。如果加上重传的冗余bit仍然无法正常解码，则进行再次重传。随着重传次数的增加，冗余bit不断积累，信道编码率不断降低，从而可以获得更好的解码效果。 * 4.3.1 Services provided to upper layers The following services are provided by RLC to upper layer (i.e. RRC or PDCP): - TM data transfer; - UM data transfer; - AM data transfer, including indication of successful delivery of upper layers PDUs. 4.3.2 Services expected from lower layers The following services are expected by RLC from lower layer (i.e. MAC): - data transfer; - notification of a transmission opportunity, together with the total size of the RLC PDU(s) to be transmitted in the transmission opportunity. * * E-UTRAN initiates the paging procedure by transmitting the Paging message at the UEs paging occasion as specified in TS?36.304 [4]. E-UTRAN may address multiple UEs within a Paging message by including one PagingRecord for each UE. E-UTRAN may also indicate a change of system information, and/ or provide an ETWS notification or a CMAS notification in the Paging message. * * The purpose of this procedure is to modify an RRC connection, e.g. to establish/ modify/ release RBs, to perform handover, to setup/ modify/ release measurements. As part of the procedure, NAS dedicated information may be transferred from E-UTRAN to the UE. E-UTRAN may initiate the RRC connection reconfiguration procedure to a UE in RRC_CONNECTED. E-UTRAN applies the procedure as follows: - the mobilityControlInfo is included only