基于EM算法的OFDM系统频偏跟踪和信号检测技术

正交频分复用（OFDM）技术对载波频偏具有敏感性,而实际通信系统中频偏随收发两端振荡频率差和多普勒频移的变化而变化,对时变的频偏进行有效地跟踪可以提高整个通信系统的性能。根据最大似然（ML）检测准则,提出了基于最大期望（EM）算法的频偏跟踪和信号检测技术。计算机仿真结果表明,算法可以在保证信号进行最大似然检测的基础上,有效的跟踪时变频偏。

Frequency Offset Track and Signal Detective Technique in OFDM Systems Based on EM Algorithm

Orthogonal frequency division multiplexing（OFDM） system has the sensitivity to frequency offset.The frequency offset is mutative,because the difference of frequency between transmitter and receiver and the doppler shifts of channel is mutative in the actual communication systems.So tracking mutative frequency offset accurately can enhance the performance of whole OFDM system.Based on maximum-likelihood（ML） detective rule,this paper presents the frequency offset track and signal detective technique in OFDM systems based on EM algorithm.Computer simulations show that this technique can ML detect signal,and track frequency offset effectively.