改进的OFDM迭代最大似然定时同步方法

Improved Iterative ML Symbol Timing Algorithm for OFDM Systems

针对基于循环前缀的ML定时同步方法和迭代ML算法不适用于多径信道和瑞利衰落信道的问题,提出一种改进算法。进行一次ML算法得到定时估计,作为迭代ML算法的初始值,利用多组数据联合估计来克服多径衰落和瑞利衰落的影响。仿真结果表明,该算法在AWGN信道、多径信道和瑞利衰落信道条件下均能进行有效定时同步。

The maximum likelihood （ML） timing algorithm based on cyclic prefixes and the iterative ML algorithm are inefficient for multi-path and Rayleigh channels. An improved timing synchroniza- tion algorithm is presented. This algorithm conducts initial symbol timing offset （STO） estimation following the traditional ML algorithm, and updates the STO estimation during the iteration. An unit- ed estimation of multiple segments of received data is utilized to overcome multipath fading and Ray- leigh fading. The simulation results indicate that the proposed algorithm is efficient for the AWGN channel, multipath channel as well as Rayleigh channel.