一种OFDM中继系统的有限反馈预编码方法

摘要

Based on OFDM amplify-and-forward cooperative relay system, in order to reduce the transmission bit error rate, while increasing the channel capacity and improving the usability, the paper presents a practical limited bits feedback precoding method where the source node precoder and the relay node precoder are jointly optimized. Through the use of the two downlink with three nodes, the two-hop cooperative communications are achieved, and the precoding matrices are designed using both orthogonal triangular (QR) decomposition and Singular Value Decomposition (SVD), in which the source node precoder contains only one precoding matrix per OFDM frame. By choosing a better codebook, the quantization precoders are feedbacked to the transmitter. The simulation results indicate that the proposed method is able to improve the system average sum-rate, reduce the error rate and improve the performance of outage probability, indicating a chance of better usability as result of fewer bits.%基于正交频分复用的放大转发协作中继系统，为了减少系统误比特率、增加信道容量和增强实用性，该文提出一种实用的源节点预编码和中继节点预编码的联合优化有限比特反馈的预编码方法。利用3节点构成的两个下行链路，实现两跳协作通信方式；采用SVD分解和QR(orthogonal triangular)分解相结合设计预编码，其中源节点预编码每帧只要一个；优选量化码本，把预编码矩阵量化后反馈到发射端。仿真结果表明，该方案能提高平均和速率、降低误码率和改善中断概率特性，且反馈比特数较少具有更好的实用价值。