【作者】 李新民；

【导师】 韦惠民；

【作者基本信息】 西安科技大学 ， 通信与信息系统， 2004， 硕士

【摘要】 正交频分复用(OFDM)技术已经在无线通信领域有了广泛应用，它将是未来无线宽带接入系统的基本技术之一，并且已经被业界定为未来移动通信系统的核心技术。载频偏移问题是OFDM技术应用要解决的关键之一，它对系统的性能影响很大，近年来成为人们研究的热点。 本文简单介绍了OFDM系统的产生、发展，及其基本工作原理、特点和技术优势。在此基础上讨论了四类载波频率偏移估计算法的主要思想和各自的优缺点，并提出了一些改进方法。 作者研究了MLE、SCA及其改进方法和两种基于子空间的算法：类 MUSIC和类ESPRIT算法．分析了它们的主要思想、实现方法和各自的优缺点．并分别进行了仿真；改进了MLE结合SCA的方法，提出了在得到较准确的帧定时后使用SCA算法进行整个粗细频偏估计的方法，仿真结果表明它有更好的估计精度和较小的计算量；创造性地采用两种经典的ESPRIT方法(LS．ESPRIT和TLS—ESPRIT)估计载波频率偏移，也达到了与类ESPRIT算法相近甚至更好的估计性能；最后作者把频偏估计算法应用于一个设计的OFDM系统中，仿真表明应用频偏估计及校正方法很好地消除了载频偏移的影响，保证了良好的系统性能。更多还原

【Abstract】 Orthogonal Frequency Division Multiplexing(OFDM)has been extensively used in theareaofradio communication systems，itwillbethebasictechniqueofthefuturebroadband radioaccess system，and also has been considered as the core technique of future mobilecommunication system．Cartier frequency offset is the key problem to use OFDM,soresearchers recently focus on it． This paper simply introduces the emergence，development,basic working theory,characteristics and the merits of OFDM systems．Four calTier frequency offset estimationalgorithms are respectively discussed about their chief theories，classical algorithms andproblems that they have．Then it proposes some new modified methods to estimate CalTierfrequency offset． With the basic MLE，SCA algorithms and MUSIC-Like，ESPRIT-Like which belong tothe subspace cartierfrequency Offset estimation algorithms being researched,they are simulatedrespectively．Then this paper modified the combination method,itfirst attains more exact timingestimation based on MLE，then estimates entire frequency offset based on SCA．Simulation results show that this new method is of better precision and little computation．Two Novel algorithms belonging to classical subspace method,LS—ESPRIT and TLS-ESPRIT,are also proposed to estinaate carrier frequency offset．They have the same even better estimation performance as ESPRIT-Like．At the end ofthis paper a simple simulation about appfication estimation algorithms to OFDM systems shows that they are feasible and efficient to maintain good system performance．更多还原