OFDM系统中基于导符号和判决数据的频率跟踪环路  

The Frequency Tracking Loop for OFDM Systems Based on Pilot Symbols and Decision Data

作　　者：郑来波[1] 胡健栋[2] 

机构地区：[1]山东大学信息科学与工程学院,山东济南250100 [2]北京邮电大学电信工程学院,北京100876

出　　处：《电子学报》2006年第1期127-130,共4页Acta Electronica Sinica

摘　　要：在相干正交频分复用(OFDM)系统中为跟踪多径信道的实时变化通常在时频网格上插入导符号来进行信道估计.对利用这些导符号结合判决数据进行频率跟踪的算法作了进一步的研究.在时域和频域都重新推导了频偏的估计结果,经过合理近似,得到了时域最大似然估计的近似解;在频域推导了另一种形式的似然函数,得出了最大似然估计的解析表达式.新的频率跟踪算法降低了计算量,提高了频率同步的精确度.In coherent orthogonal frequency division multiplexing systems, the pilot symbols are often inserted into time-frequency grid to tracking the real time variation of the channel response. The frequency synchronization algorithm using these pilot symbols was further analyzed. By modifying the derivation procedures both in time domain and frequency domain, and by the proper approximation, the approximate maximum likelihood estimation result in time domain was derived. Meanwhile, a different form of likelihood function in frequency domain was derived, and the analytical estimation result was also given. The new tracking algorithm decreases the computational complexity greatly, and increases the accuracy of the frequency synchronization.

关 键 词：OFDM系统 载波频率偏移 最大似然 跟踪 

分 类 号：TN911.7[电子电信—通信与信息系统]