合作分集无线网络中一种改进的分布式空时编码

A modified distributed space-time code in cooperative diversity wireless network

将多天线系统中线性空时编码的思想用于合作分集无线网络,提出一种改进的分布式线性空时编码。在通信时采用两段协议,第一阶段信源向所有的合作伙伴发送信息T个符号,在第二阶段各合作伙伴对接收到的经噪声干扰的信号根据瞬时信道状态进行分布式线性处理后发送到接收端。对成对错误概率(PEP)进行分析,给出一种chernoff上界,并与多天线系统进行比较。对于总发送功率P固定的无线网络,最优功率分配方法是信源分配一半的功率,分配给网络中所有合作伙伴一半发送功率。仿真结果表明在高信噪比时,所提出的分布式空时编码方法在各终端均配置单天线的条件下可以达到R根发送天线的多天线系统的分集度。

The idea of linear space-time coding devised for multiple-antenna system is applied to communication over wireless cooperative network. A two-stage protocol is used in the network communications, where in one stage the transmitter transmits information and in the other, the cooperative partners process their received signals linearly and then transmit the code signals to the receiver. The pair error probability is analysised and get a chernoff upper bound. It is further shown that for a fixed total transmit power across entire network, the optimal power allocation is that the transmitter expend half the power and the partners collectively expend the other half. The simulation shows that the network has the same diversity as a multiple antenna system with R transmit antenna, which is same as assuming that R partners can fully cooperate and have full knowledge of the transmit signal.