基于预编码的双路径中继系统信号传输方案研究

针对转发放大(Amplify-and-Forward, AF)模式下的双路径中继网络，为了降低训练序列设计相互约束关系的复杂度，并提升系统误码性能，本文提出了一种基于预编码的信号传输方案。新方案采用一对相互正交的预编码矩阵，分别在两个中继处对信号进行预编码，在目的点右乘相应的解码矩阵将两路叠加信号分离。新方案能够将两路信号完全分离从而使原本需要考虑三处训练序列设计的问题转化为两处，简化了训练序列设计复杂度。由于预编码方案能够在目的点压缩噪声功率，并且避免两路中继信号的互相干扰，单路径误码性能和双路径分集合并误码性能都得到提升。仿真结果验证了新方案的有效性。 

Research on Signal Transmission Scheme of Two-Path Relay System Based on Precoding

In order to reduce the complexity of the constraints between training sequences and improve the performance in amplify-and-forward (AF) two path relay network, this paper proposes a signal transmission scheme based on precoding. In this new scheme, a pair of orthogonal precoding matrices are used to precode the signals at two relays, and the superimposed signals are separated by multiplying the corresponding decoding matrices at the destination. The new scheme can completely separate the two signals so that the original need to consider three training sequence design problems can be converted into two, which simplifies the complexity of training sequence design. Because the precoding scheme can compress the noise power and avoid the interference between two relay signals at the destination, the performance of single-path and two-path diversity combining bite error rate (BER) are improved. The simulation results verify the effectiveness of the new scheme.