说明：  ：载波频率偏移是OFDM系统实现的关键问题之一。分析了OFDM 系统载频偏移估计的2 种算法，即利用循环前缀和训练序列方法。它们均为最大似然估计方法。分别讨论了它们的基本 思想、实现方法和仿真结果。可以看出基于循环前缀算法复杂度较小，精度不高，而基于训练序列 的算法有较高的估计精度，但降纸了系统传输效率。
(Abstract：Carrier frequency ofset is one of the key problems in OFDM system．Two foundational methods 。cycling prefix—based and training sequence—based algorithms。to estimate OFDM carriers~equency ofset are analyzed．Then it discusses their basic thoughts。implementing methods and simulation resuits． Finally。merits and demerits of every algorithm are supposed．It concludes that the cycling prefix— based algorithm has less complexity and less precision。and that the training sequence—based algorithm has better estimation performance at the cost of transmission efficiency．)