OFDM系统中面向判决的同步与信道联合估计算法

A Combined Symbol Timing and Frequency Synchronization and Channel Estimation Technique Based on Detected Data for OFDM Systems

该文提出了一种新的面向判决的OFDM时间和载波频率偏差与信道的联合跟踪算法,并给出了开环和闭环两种结构,不同结构适用于不同的信道环境。该算法提取出信道估计结果所包含的同步信息用于实现同步估计,然后利用当前同步估计结果对信道估计结果进行修正,使之尽量逼近真实信道。采用闭环结构并适当地选择块长和反馈因子的取值,该算法可以有效地对时变信道进行跟踪。

A new combined symbol timing and frequency synchronization and channel estimation technique by using the detected data is developed for OFDM systems. Open-loop and closed-loop schemes are described in details. The synchronization information contained in the channel estimated results which is gained by LS channel estimation method is extracted based on the Maximum Likelihood （ML） criterion for synchronization estimation, and then the estimated results of symbol timing and frequency are used to correct the initial estimated channel and make it be more equal to the real channel more. Select appropriate length of the block and the value of feedback factors, the algorithm can be used to tracking the time variable channel.