基于不完全信道信息的MIMO双向中继系统线性预编码算法

Linear precoding scheme for MIMO two-way relay system with imperfect channel state information

针对配置两个通信节点的多输入多输出双向中继系统,提出一种基于不完全信道状态信息的预编码设计方案,该方案综合考虑信道估计误差与信道反馈延迟的情况。在中继发射功率受限的条件下,以最小均方误差为准则设计以预编码矩阵为变量的优化问题,提出矩阵分解和联合迭代两种线性预编码算法。矩阵分解法通过矩阵分解推导得到中继矩阵的闭式解;联合迭代法利用迭代算法交替迭代来联合优化预编码矩阵和接收端处理矩阵,直到算法收敛数。仿真结果表明,随着信噪比由0到25dB逐渐增大,与现有方案相比,矩阵分解法能有效地降低系统的误比特率,联合迭代法能获得最佳的系统性能提升。

A linear precoding design scheme based on imperfect channel state information is proposed for multiple input multiple output MIMO two-way relay system with two communication nodes.This scheme considers the channel estimation error and feedback delay.The design of transceiver is simplified as an optimal problem with precoding matrix variables,which is deduced with the maximum power constraint at the relay station based on the minimum mean-square error criterion.With channel feedback delay at both ends of the channel and the channel estimation errors are taken into account,the matrix decomposition scheme and the joint iterative scheme are proposed to minimize the average sum mean-square error.Numerical simulation results show that the matrix decomposition scheme can improve the system bit error rate（BER）effectively and the joint iterative scheme achieves the best performance of BER with the increase of signal-to-noise ratio against existing methods.