Abstract: A frequency offset estimation algorithm with pilot-data assisted jointly based on the framework of the Expectation-Maximum（EM） algorithm is proposed in order to deal with the conflict between estimation accuracy and spectral efficiency for burst-mode transmission systems.Furthermore，the improved recursive EM estimation algorithm is proposed.Theoretical analysis and simulation results show that it is more accurate to estimate frequency offset from both pilot symbols and data symbols than from pilot symbols only.The joint estimator attains the CRLB with a large number of pilot symbols at moderate high Signal-to-Noise Ratios（SNR），and is superior in performance to the non-data aided blind estimator at low SNR.

Key words: Expectation-Maximum（EM） algorithm, frequency offset estimation, joint estimation, data-aided, blind estimation

摘要： 针对突发通信系统在保证频率估计精度和频谱效率时存在的矛盾，提出了一种基于EM算法结构的导频与数据联合辅助的频偏估计算法，在此基础之上进而提出了改进的递归EM估计算法。理论分析和仿真实验表明，相比于仅使用导频的估计算法，联合使用导频和数据进行频偏估计的性能更加精确，在高信噪比下达到了使用更多导频符号估计的克拉美罗下界，并且在低信噪比条件下，其性能要优于非数据辅助的盲估计算法。

关键词: 期望最大化算法, 频偏估计, 联合估计, 数据辅助, 盲估计