【作者】 陈伟；

【导师】 席志红； 李景辉；

【作者基本信息】 哈尔滨工程大学 ， 电子与通信工程（专业学位）， 2016， 硕士

【摘要】 均衡技术在现代移动通信系统中发挥着重要的作用。在单载波系统中,抵抗频率选择性衰落信道的符号间干扰均衡器得到了广泛的研究。对于OFDM系统而言,尽管其自身的调制和解调结构可以天然的抵抗频率选择性信道,然而随着近年来研究的深入,在频率时间双选择性衰落信道下OFDM系统的均衡技术研究也日益成为了 OFDM接收机研究热点之一。论文首先介绍了 OFDM系统在时变多径衰落信道下ICI均衡技术的基础知识。主要包括利用FFT变换快速得到频域信道矩阵的方法,ICI功率分布的数学表达式和时变多径瑞利信道下的匹配滤波界的推导过程,以及经典的ICI均衡算法。接着本文重点研究了低复杂度的ICI均衡算法。传统均衡器的复杂度是很高的,因此次优的低复杂度均衡器成为了人们研究的重点。本文分析了基于递推求逆的LMMSE均衡算法和基于矩阵分解的LMMSE均衡算法,在此基础上得出了简化的LMMSE均衡算法,该算法能够实现性能和复杂度的折衷,计算复杂度相对较低,易于工程实现。更多还原

【Abstract】 Equalization techniques play important roles in modern wireless communication systems.For single carrier systems, the inter symbol interference equalization method, which can resist frequency selective fading channel, has attracted extensive research work. For OFDM systems,the multi-path interference can be suppressed by its inherent characteristics. Recently, a variety of equalization methods have been proposed to mitigate frequency-time selective fading channel for OFDM systems.Firstly, we introduce the basic knowledge of ICI equalization for OFDM systems over time-varying multi-path channels,including a method about how to quickly get the frequency domain channel metrix using FFT, the derivation process of ICI power distribution and matched-filter bound, also the traditional ICI equalization algorithms.This thesis focused on reduced-complexity equalizers. The traditional equalizers have a prohibitive complexity, which leads researchers to paying more efforts to the suboptimum but low-complexity equalizer. In this paper we study several low-complexity equalization algorithms, including recursive linear MMSE equalizer and another equalizer based on matrix decomposition. Based on this,we propose a partial MMSE equalizer,which can achieve a compromise of performance and complexity for the relatively low computational complexity and implementing easily to project implementation.更多还原