上行多用户MIMO中继系统中基于不完全信道状态信息的预编码算法

摘要

This paper investigates transceiver design for dual-hop up-link multi-user Multiple-Input Multiple- Output (MIMO) system with Amplify-and-Forward (AF) relay to improve the performance of Bit Error Ratio (BER) under the imperfect Channel State Information (CSI). Since the antenna correlation at both ends of the channel and the channel estimation errors are taken into account, a robust transceiver design is proposed. The optimization issue is formed with Minimum Mean-Square Error (MMSE) rule firstly. Then the relaying matrix and the optimal source precoding matrix are optimized at the maximum power constraint of the transmitter and relay station subsequently. Finally, the equalizer is optimized by a gradient-based line search algorithm. Simulation results indicate that the proposed design approach achieves better robustness against antenna correlation and channel estimation errors than existing methods.%论文研究了存在信道估计误差及天线相关条件下，上行多用户MIMO中继系统的预编码问题，目标是提升系统的误比特率性能。针对基于放大转发中继技术的上行多用户 MIMO 中继系统，考虑源-中继和中继-目的端信道中存在的信道估计误差及天线相关，提出一种基于不完全信道状态信息(Channel State Information, CSI)的预编码设计方案。首先根据最小均方误差(Minimum Mean-Squared Error, MMSE)准则设计代价函数，以发射端和中继端最大功率为约束条件，通过理论推导求得中继端和发射端的线性预编码矩阵，最后采用迭代下降法得到接收端处理矩阵的闭式解。数值仿真结果表明，在存在信道估计误差和天线相关的条件下，与现有算法相比，所提算法能有效降低系统的误比特率。