放大转发OFDM中继系统的一种叠加导频辅助信道估计和联合数据检测算法

Superimposed pilot aided channel estimation and joint signal detection for amplify-and-forward relays in an OFDM system

针对源节点和目的节点之间没有直接路径的放大转发（AF）OFDM中继系统，提出了一种利用叠加导频（SP）进行信道估计和联合数据检测的算法。该算法首先将接收信号通过白化滤波器进行信号白化，然后利用SP获得等效信道的信道状态信息（CSI）初始估计值，并联合目的节点上的最大比合并（MRC）接收机，通过判决反馈迭代操作不断改进信道估计的性能。据此算法推导出了使用白化滤波器的AFOFDM系统平均误符号率（ASER）的理论闭式表达式。理论分析和仿真结果表明，由于使用叠加导频，此算法在提高系统频谱利用率的同时，能够获得较好的信道估计和数据检测性能。

The authors of the paper utilized the superimposed pilot （SP） to estimate the initial channel state information （CSI） of the equivalent channels of amplify-and-forward （AF） OFDM relaying systems without the direct channel between the source node and the destination node, and formed the SP aided channel estimation and joint signal detection algorithm with the help of the maximal ratio combining （MRC） receiver at the destination node. Meanwhile, the closed form of the theoretical average symbol error ratio （ASER） for the proposed algorithm was derived. The simulation results show that the proposed algorithm can obtain the satisfactory performance while the spectral efficiency can be improved because of using the SP.