宽带无线通信中的MIMO-OFDM技术研究

【作者】 童军；

【导师】 龚耀寰；

【作者基本信息】 电子科技大学 ， 信号与信息处理， 2004， 硕士

【摘要】 未来无线通信系统应能在时间-频率选择性衰落信道中以低成本提供可靠的高速数据传输服务。多入多出(MIMO)技术作为近年来无线通信传输技术研究中最大的突破之一，利用信道多径效应，能够极大改善无线通信的频谱效率和通信可靠性，为实现这一目标提供了强有力的技术手段。同时，1960年代提出的多载波调制技术(OFDM技术)，由于能够显著简化系统接收机的设计并具有优越的频谱效率，最近也获得了极大的关注。二者的结合即MIMO-OFDM系统以被认为是未来移动通信系统(B3G/4G)最有可能选用的技术方案并开始被标准化系统采纳。然而，为在实际系统中获得优异的性能改善，一方面必须对MIMO-OFDM系统特性作深入研究，另一方面也必须研究和开发更为有效的信号处理算法。面向这一目标，针对MIMO-OFDM系统，本文主要：1)研究了宽带MIMO双选择衰落信道特性、重要参数、建模和计算机仿真方法；2)分析了MIMO-OFDM系统中子载波数和循环前缀等重要参数对通信速率和服务质量(QoS)的影响及折中的MIMO-OFDM系统参数设计方法；针对更广泛的MIMO无线信道，分析了MIMO-OFDM系统的容量；3)研究了发射分集MIMO-OFDM系统的发射接收方案，重点讨论了空频编码(SFC)和空时分组编码(STBC)在MIMO-OFDM系统中的应用及分组分层方案在MIMO-OFDM系统中的应用，通过计算机仿真探索了系统配置和信道特性对系统性能的影响；4)设计了适用于MIMO-OFDM系统的基于插值的导频符号辅助的信道估计算法，并提出了一种新型的适用于MIMO-OFDM系统的自适应信道估计方案，包括其参考导频图案及LMS和RLS自适应信道追踪算法。本文关于MIMO-OFDM的研究工作可为改善无线通信系统的信息传输速率及提高其可靠性提供参考。更多还原

【Abstract】 Future broadband wireless communication systems should be able to provide reliable high-data-rate transmissions at low cost in time and frequency selective wireless channel. Multiple Input Multiple Output (MIMO) technique, one of the most significant breakthroughs in wireless communications field offers an effective way to combat and even exploit fading. However, in order to put this novel idea into practice, more effective signal processing techniques should be developed. After near 30 year’s development, Orthogonal Frequency Division Multiplexing (OFDM), proposed in 1960s, now has gained much attention with its ability to reduce system complexity. MIMO combined with OFDM has been regarded as a potential candidate for Fourth Generation (4G) mobile communication.To make a thorough understanding of MIMO-OFDM system, in this thesis the author: 1) Ananlyzed the characteristics, modeling and simulation of double-selective wideband MIMO channels; 2) Ananlyzed MIMO-OFDM architectures with various trade-off between throughputs and Quality of Service (QoS); ananlyzed the channel capacity of MIMO-OFDM systems; 3)Researched the design criteria of Space-Frequency codes (SFC) and their application in MIMO-OFDM systems, and researched into the influence of system configuration and channel type on the system performance; 4) Explored the channel estimation methods based on pilot symbol assistance to provide channel status information which are necessary for utilizing the benefit of MIMO-OFDM . The research on MIMO-OFDM offers the potential for enhanced performance, capacity and high-speed delivery of information in broadband wireless communication systems. The ultimate goal is to provide more choices for future multimedia wireless networks.更多还原