简单高效的新型多向中继网络编码方法

为进一步提升全信息交互的多用户多向中继网络的吞吐量和传输可靠性,提出一种简单高效的新型网络编码方法.本文方法基于多级双向网络编码操作,用户两两配对同时向中继节点发送信息符号,中继通过对接收的叠加信号进行硬判决检测以确定这两个符号是否同号,并将判决结果广播给所有用户.如果同号,则可确定这两个用户各自的发送信息;如果异号,则任意选出其中一个用户,参与下一轮配对,直到实现所有用户的信息交互.理论分析和仿真结果表明提出方法较传统路由方法和现有的二进制网络编码方法,单源单信道的吞吐量都有显著的提升.而且,由于三电平脉冲幅度调制(3-PAM)的简单特性,与大规模多向中继网络的文献方法相比,本文方法的复杂度更低,可靠性更高.此外,在加性高斯白噪声(AWGN)信道下,采用基于低密度校验(LDPC)码的新型网络编码可以进一步增强可靠性.仿真结果表明:用户数目越多,本文方法较文献方法的增益越大,并且联合信道编码后的增益进一步加大.

Simple and efficient novel multi-way relay network coding scheme

A simple and efficient novel network coding scheme was proposed to improve the throughput and transmission reliability of multi-user multi-way relay network with full-data exchange. It was based on a multi-stage two-way network coding scheme. Two paired users transmitted their information symbols to the relay node simultaneously. Then, the relay node judged whether these two symbols have the same sign by hard decision for the received superimposed signal and broadcasted the decision result to all the users. If the two symbols had the same sign, the transmitted symbols could be known. Otherwise, anyone of the two users was selected to perform the network coding in the next round. Each pair of users performed in this manner sequentially until the transmitted symbols of all the users are obtained by each other. Both theoretical analysis and simulation results indicate that compared to the plain routing scheme and the binary-signaling network coding reference scheme, the throughput per source per channel use is increased remarkably. Besides, due to the simple nature of 3-plus amplitude modulation (3-PAM), the proposed scheme has much lower complexity and much higher reliability compared to the referenced scheme for large-scale multi-way relay channels. On the additive white Gaussian noise (AWGN)channel, low density parity check (LDPC) codes are utilized in this scheme to improve the reliability. The simulation results show that the signal-to-noise ratio (SNR) gains to reference scheme increase as the number of users increases, and the SNR gains of the LDPC-coding scheme are even bigger than the uncoding scheme.