基于卷积码的网络编码协助IDMA系统容量分析

摘要

This paper designs a network-coded non-orthogonal multi-access user cooperative system, and convolutional code is employed to transfer messages. The source users' messages obtained in the relay where they get correctly decoded are XOR together and re-transmitted forward to the destination to obtain diversity gain. In the receiver, a dual iterative multi-user detection scheme is developed and the receiver architecture is redesigned. Besides, a novel performance evaluation technique for the chip-by-chip algorithm called SNR evolution technique is investigated to analyze the system capacity. Simulation results confirm that the proposed network-coded cooperation Interleave-Division Multiple-Access(IDMA) scheme based on convolutional code is an effective way to combat channel fading. It can provide obvious cooperation diversity gain and achieve noticeable Bit Error Rate (BER) improvement, and has a high system capacity.%设计了一个由网络编码协作下的非正交用户合作系统,并引入了卷积码进行编码传输.中继用户处解码后的源用户有效数据通过线性网络编码组合在一起,传送到基站从而获得分集增益.在接收端,采用一种二重迭代多用户检测办法,并提出了新的接收机方案.采用一种码片级的算法性能评估技术“SNR evolution”,对系统容量进行分析.对BER和系统容量的仿真分析表明:文中所讨论的合作机制是对付信道衰落的有效办法,它能够提供可观的用户合作分集增益,减少多用户系统的误码率；整个系统具有较高的系统容量.