无线信道中基于代价函数的OFDM频偏跟踪算法  

Frequency Offset Tracking Algorithms Base on Cost Functions For OFDM in Wireless Channel

作　　者：李鹏怀[1] 徐佩霞[1] 

机构地区：[1]中国科学技术大学电子工程与信息科学系,合肥230027

出　　处：《信号处理》2006年第2期219-225,共7页Journal of Signal Processing

摘　　要：在OFDM系统中,频偏对系统的性能有很大的影响。本文推导出两种新的实际频偏和估计频偏的差值表达式, 在此基础上,提出了相应的基于代价函数的自适应频偏跟踪算法,并在多径瑞利衰落信道中针对多种时变频偏的情况进行了计算机仿真,获得了频偏跟踪曲线和均方误差曲线。仿真结果表明,由于算法的快速收敛特性,取得了较好的频偏跟踪性能。它们克服了非自适应方法和跟踪缓慢的自适应算法难以适应时变频偏的缺点。将跟踪到的频偏在接收端补偿以后, 可以减小子载波间串扰,降低系统解调后的误码率。Carrier frequency offset influences orthogonal frequency division multiplexing system＇ s performance much. Two new expressions of difference between actual frequency offset and estimation value are proposed in this paper. Based on them, corresponding adaptive frequency offset algorithms using cost functions are presented and the tracking performance of the algorithms for many kinds of time-varying frequency offsets is simulated. The tracking curve and mean square error curve are presented. Computer simulations confirm that the algorithms have good tracking performance because their fast convergence. The algorithms overcome the non-adaptive and slow adaptive algorithms＇ difficulty to track time-varying frequency offsets. Inter-carrier interface（ICI） is minished and hit error rate of system＇ s demodulation is reduced after the value of frequency offset estimation is compensated for demodulation.

关 键 词：正交频分复用 自适应频偏跟踪 二相相移键控 多径瑞利衰落 

分 类 号：TN929.5[电子电信—通信与信息系统] TN953[电子电信—信息与通信工程]