基于不完全信道状态信息的预编码算法

Precoding Algorithm Based on Imperfect Channel State Information

针对下行多用户多输入多输出中继系统,提出一种考虑信道估计误差和天线相关的线性预编码算法。在发射端和中继端功率约束条件下,根据最小均方误差准则设计代价函数,通过理论推导求得中继端和发射端的预编码矩阵。接收端的各个用户之间相互独立时,接收端的处理矩阵为对角矩阵,通过直接求导法得到接收端预处理矩阵的闭式解,并设计迭代法联合优化预编码矩阵和接收端的处理矩阵。数值仿真结果表明,与未综合考虑各端口的预编码算法相比,该算法能降低系统的误码率。

For down-link multi-user Multiple Input Multiple Output（MIMO） relay system, a linear precoding algorithm is proposed with the channel estimation errors and the antenna correlation taken into account. The cost function is designed with Minimum Mean Square Error （MMSE） rule under the power constraint at the transmitter and relay terminals. The precoding matrix of relay and transmitter is obtained by theoretical deduction. Assuming that each user of receiver is independent of each other, the processing matrix is a diagonal matrix, so the closed form of receiving precoding matrix can be obtained by direct derivation. The iterative method is designed to jointly optimize the precoding matrix and the processing matrix at the receiver. Numerical simulation results show that compared with precoding algorithms that failed to take each port into account, the proposed algorithm can reduce bit error rate of the system.