正交频分复用（OFDM，Orthogonal Frequency Division Multiplexing）技术已经在无线通信领域有了广泛应用，被定为第四代移动通信系统的核心技术，也是未来无线宽带接入系统的基本技术之一。OFDM系统对载波频偏十分敏感，微小的频偏都将造成系统性能的急剧下降，对系统的性能影响很大，载波频偏是OFDM技术应用要解决的关键问题之一，近年来成为人们研究的热点。研究准确、高效的载波频偏估计算法是本论文的主要目的。 论文研究了当前一些典型的载波频偏估计算法，并通过仿真结果对其性能进行分析比较。论文的主要工作如下： 一、介绍OFDM系统的基本原理、结构及系统模型以及OFDM系统的主要特征。详细分析了OFDM系统中的DFT实现方法、串并变换、保护间隔和循环前缀的功能。 二、分析OFDM系统中符号定时偏差、采样定时偏差和载波频率偏差，重点分析三者对OFDM系统产生的影响。其中载波频率偏差主要的危害有两个：一是信号幅度的降低，二是相邻子载波会产生载波间干扰（ICI，Inter-Carrier Interference）。 三、研究一种基于循环前缀和两种基于虚子载波的频偏估计算法。在阐明算法基本思想的基础上，重点比较了类MUSIC和类ESPRIT算法，仿真结果表明：类MUSIC算法和类ESPRIT算法都能实现载波频偏的盲估计。类MUSIC算法可以取得很高的估计精度，其性能优于类ESPRIT算法。类MUSIC算法采用了遍历的方法使其性能受步长的影响较大，而且运算量太大，不太适应未来移动环境的要求。

OFDM (Orthogonal Frequency Division Multiplexing) technology has been widely used in wireless communication areas and defined not only the core of the fourth generation mobile communication technology but also one of the fundamental techniques of wireless broadband access system in future. OFDM system is very sensitive to carrier frequency offset and the system performance can be seriously degraded even by slight frequency offset. Carrier frequency offset is one of the key problems to be solved in OFDM technology application and has become a hot research topic recently. The paper focuses on research of accurate and efficient estimate algorithms of carrier frequency offset. The paper studies several typical estimate algorithms of carrier frequency offset currently and compares their performance based on simulation results. The paper mainly involves works as follow: (1) Introduction of fundamental principles, structure and system model, characteristics of OFDM system. Detailed analysis of DFT implement methods, series-parallel transformation, guard intervals and cyclic prefix function. (2) Analysis of symbol timing offset, sampling timing offset and carrier frequency offset of OFDM system, with the focal point of their influence on OFDM system. There are two main jeopardizes of carrier frequency offset. One is degradation of signal amplitude and the other is ICI (Inter-Carrier Interference) due to adjacent subcarriers. (3)Analysis of one frequency offset estimate algorithm that based on cyclic prefix and another two based on virtual subcarriers. Similar MUSIC and similar ESPRIT algorithms are analyzed and compared after illustration of principal thoughts of the algorithms. Simulation result shows that both of the two methods can realize blind estimate of carrier frequency offset. Similar MUSIC algorithm can achieve relative high estimate accuracy and its performance exceeds that of similar ESPRIT algorithm. The performance of similar MUSIC algorithm is largely influenced by step-length due to its adoption of ergodic method. Besides, similar MUSIC algorithm has relatively large calculation volume and is not suitable for mobile environment requirement in future.