基于最大似然算法的OFDM频偏估计研究

摘要

Because the high spectrum efficiency and transmission reliability for OFDM are based on the orthogonality between the sub-carriers, it has very important significance to estimate and compensate the frequency deviation for OFDM symbol effectively. Since almost multi-carrier system through inserting the cyclic prefix to eliminate ISI, and the samples of each N interval has the correlation after the introduction of the cyclic prefix, the Maximum Likelihood algorithm was employed to estimate the frequency deviation. At last, the algorithm was confirmed by Monte Carlo approach, the results indicate that the deviation between the estimated frequency deviation and the actual frequency deviation is very small.%由于OFDM的高频谱利用率和传输可靠性均是以子载波间的正交性为基础的,因此对OFDM符号的频率偏差进行有效的估计和补偿具有非常重要的意义。由于多载波系统几乎都采用插入循环前缀的方法来消除符号间干扰，引入循环前缀后，每对间隔为N的样值之间具有相关性,因此利用循环前缀所携带的信息,采用最大似然估计方法进行频率偏差的估计，最后通过Monte Carlo方法对其进行了仿真验证,结果显示估计频偏与实际频偏的偏差很小。