LTE通信系统中D2D多播传输方案设计

Design of the D2Dmulticast transmission scheme in the LTE communication system

为了提高长期演进通信系统中的频谱效率以及传输可靠性,将长期演进通信网络的终端用户划分成终端直通通信簇,通过基站多播数据包给所有簇头以及各簇头在终端直通通信簇内广播数据包这两跳传输,实现长期演进通信系统中数据包的多播传输.鉴于终端直通通信簇内用户链路不可靠,考虑采用基于网络编码的自动重传请求重传算法,利用建立的丢失数据包列表,簇头对需要重传的数据包进行网络编码,广播编码数据包,减少重传次数.性能分析和仿真结果表明,该方案可以获得与已有基于时间的网络编码重传方案相同的传输效率,具有较低的计算复杂度.相对于传统蜂窝通信模式下基于网络编码的多播重传方案,只在终端直通簇内进行数据包重传,高丢包率时有效减少基站发送数据包的次数,降低了蜂窝网络频谱资源的消耗.

In order to improve spectrum efficiency and transmission reliability of the LTE communication system, its terminal users can be divided into the D2D communication cluster. Specially, the multicast transmission of data packets in the LTE system can be realized through two hop transmissions, namely, the base station multicasts data packets to all cluster-heads and each cluster-head in the D2D communication cluster broadcasts the received packets. Considering that the links may be unreliable in the D2D communication cluster, the ARQ retransmission algorithm based on network coding is adopted. By establishing the lost-packet list, the cluster-head operates the lost-packets by network coding, and broadcasts the encoded packets to reduce the number of retransmission. Performance analysis and simulation results show that the proposed scheme can achieve almost the same transmission efficiency as the existing scheme, but has a lower computational complexity. Compared with the traditional multicast retransmission scheme based on network coding in the cellular communication mode, the scheme only retransmits the lost-packets in D2D cluster, to reduce the pachets transmission number of base stations and decrease the spectrum resource consumption of the cellular network effectively at a high packet loss rate.