【作者】 贾玉晶；

【导师】 李一兵；

【作者基本信息】 哈尔滨工程大学 ， 通信与信息系统， 2007， 硕士

【摘要】 OFDM(正交频分复用)的基本原理是将高速的数据流分解成许多低速率的子数据流，利用相互正交且重叠的多个子载波同时传输。它的主要优点是多径失真低，抗符号间干扰(ISI)能力强，频带利用率很高。无线信道的一个重要特点是多径传播，它使接收信号相互重叠，产生符号间干扰(Intersymbol Interference，ISI)。OFDM在频域把频谱分成许多正交子载波，各子载波间保持正交，频谱相互重叠，提高了频谱利用率，同时大大减小了符号间干扰。OFDM适用于多径环境和频率选择性衰落信道中的高速数据传输。OFDM系统面临的一个主要问题是对频率偏移的敏感性，频率偏移将导致载波间干扰(ICI)的产生，从而大大降低系统性能。本文对由频率偏移而导致的ICI进行了理论分析，并对抑止ICI的三种方法：自消除方法(SC)、最大似然估计方法(MLE)及扩展Kalman滤波方法(EKF)进行了仿真和性能比较。更多还原

【Abstract】 The basic principle of OFDM is to split a high rate data stream into a number of lower rate streams that are transmitted simultaneously over a number of sub carriers. The benefits of OFDM are lower multi-path distortion, resiliency to inter symbol interference and high spectral efficiency.One of the most important characteristics of wireless communication is multipath transmition. Multipath transmition results in signals overlapping each other, and brings to Intersymbol Interference (ISI). The Orthogonal Frequency Division Multiplexing (OFDM) technique divides the frequency spectrum available into many independent sub-carriers. The sub-carriers keep orthogonal to one another and the spectrum overlap. It increases the spectral usage efficiency, and at the same time, it can reduce ISI greatly. The OFDM technique is applicable to high-speed data transfer in environment of multipath and frequency selectivity channel.OFDM system faces a major problem is the sensitivity of frequency offset. Frequency Offset will lead to the ICI. It greatly reduces system performance. This article analysis the ICI caused by the frequency offset, ICI is also curbed by the three methods: SC, MLE and EKF for the simulation and performance ratio more.更多还原