基于高斯消息传递的频域EM信道估计算法

基于turbo迭代原理和高斯消息传递EM算法，对单载波传输系统进行联合信道估计与均衡。利用高斯消息传递的观点在因素图中对期望最大化进行描述，分析并提出合理的简化算法，避免了复杂矩阵求逆运算，之后借助于快速傅里叶变换，使得算法只有对数复杂度。仿真结果表明，在时变多径信道下，所提算法在获得较好的性能同时，显著降低了计算复杂度。

Frequency Domain EM Channel Estimation Algorithm Based on Gaussian Message Passing

A new joint equalization and channel estimation algorithm is proposed for single carrier systems based on turbo principle and Gaussian message passing algorithm, and the expectation-maximization （EM） algorithm is viewed as message passing in factor graphs. By using a frequency-domain system model and introducing proper approximations in the message computations, the complexity of the proposed approach avoids matrix inversion and grows logarithmically with the length of the observation vector. Simulation results show that the new algorithm can achieve good performance with low computational complexity over time-varying frequency selective channels.