基于期望最大化算法的联合符号检测和相位估计算法

Joint symbol detection and phase estimation algorithm based on expectation-maximum

针对带有未知载波相位的符号检测问题,提出了一种基于期望最大化(EM)算法的联合符号检测与相位估计算法,该算法改变了传统最佳接收算法中先估计载波相位再进行符号检测的分级处理方式,直接通过EM算法进行符号检测。在算法收敛之后,判决获得符号信息的同时,可得到未知载波相位的最大似然(ML)估计,从而实现了符号信息与载波相位的联合估计与检测。由于该算法不需要进行同步参数估计,因此可以大大降低传统最佳接收方法分级处理方式所带来的性能损失。仿真实验表明,该算法与传统最佳接收算法中先通过非数据辅助(NDA)方法估计载波相位再进行符号检测相比,性能有明显提升,可以达到导频辅助下的符号检测性能,由于不需要估计载波相位,因此处理复杂度大大降低。

In this studied. A joint paper, the problem of symbol detection in the presence of unknown carrier phase is symbol detection and phase estimation algorithm based on the Expectation-Maximum （EM） algorithm is developed, which is different from the traditional optimum receive algorithm. The algorithm does not need to estimate the carrier phase and obtain symbol information directly. After the algorithm convergence, it obtains signal information, at the same time estimates the maximum- likelihood （ML） of unknown carrier phase, and consequently realizes the joint symbol detection and phase estimation. Because the algorithm does not require synchronization parameters estimation, it can reduce the loss of performance, which is brought by the hierarchical processing of the traditional method. Simulation results show that, in comparison with the traditional optimum receive algorithm, which has to estimate the phase by non-data-aided first, then detect symbol information, the performance of the proposed algorithm is improved significantly.