【作者】 朱隆晶；

【导师】 肖井华；

【作者基本信息】 北京邮电大学 ， 物理电子学， 2008， 硕士

【摘要】 随着社会的发展,人们希望移动通信系统能够支持视频、图像、数据、话音等多种业务同时综合传输,这就要求未来的B3G移动通信系统提高系统传输的有效性来满足这种快速传输大量数据的需求。因此,在未来移动通信关键技术的研究中,能够提高系统传输有效性的技术始终是研究的热点。由于有效性这个评价通信系统优劣的重要指标与另一个重要指标可靠性通常是矛盾的,因此往往是根据实际要求互相兼顾,有所侧重。本文研究的AMC(自适应编码调制)技术就是一种在满足一定可靠性的情况下提高传输有效性的技术。论文介绍了MIMO-OFDM通信系统的原理。首先介绍了MIMO的信号模型、信道容量以及MIMO技术的种类,重点讨论了我们研究中要用到的V-BLAST的原理及其检测算法、预编码的原理;然后介绍了OFDM的基本原理,包括其基本模型、OFDM信号的生成、保护时间和循环前缀、加窗技术、OFDM系统的PAPR问题等;最后给出了MIMO-OFDM的系统基本模型和信号模型。论文阐述了自适应编码调制技术的原理与实现。在介绍了这种技术的基本原理之后讨论了在本文中这种技术要用到的Turbo码的编译码方法,QPSK和16QAM两种调制解调方式;然后讨论了在OFDM系统中实现AMC需要用到的计算有效信噪比的EESM映射方法,以及AMC传输模式选择的两种准则:误块率达到一定要求或吞吐率最大。论文研究了MIMO-OFDM系统中的AMC技术的性能。通过仿真得出了不采用AMC技术的V-BLAST系统、采用AMC技术的V-BLAST系统、同时采用AMC技术和预编码技术的V-BLAST系统这三种情况下的性能结果。通过对仿真结果的分析可知,采用了AMC技术和预编码技术之后,系统的吞吐率有了比较大的提高,即系统的有效性提高了,系统性能得到了改善。更多还原

【Abstract】 With the development of society, mobile communication system support video, image, data and conversation services simultaneously are required. In order to satisfy the demand of transmitting large data rapidly, it need improve the efficiency of system transmitting data in the future Beyond Third Generation mobile communication systems. Therefore, the future mobile communication key techniques that can improve the efficiency of system transmitting data are always hot research topics.Efficiency is one of important indexes to evaluate a communication system performance. But efficiency generally conflict with robustness which is another important evaluating index. Therefore, it should banlance the two indexes according to request and emphasize particularly on one of them some times. The Adaptive Modulation and Coding (AMC) technique studied in this thesis is a kind of technique that can improve efficiency when robustness satisfies the system request.The thesis introduces the principle of MIMO-OFDM communication system. Firstly, we present the signal model, channel capacity and types of MIMO. We emphasize the principle and detecting algorithm of V-BLAST and the principle of precoding which will be used in our research. Then, the thesis introduces OFDM principle include system model, the creation of OFDM signal, guard interval, cyclic prefix, windowing and PAPR of OFDM system. Based on the descriptions of MIMO and OFDM, we introduce the MIMO-OFDM system model and signal model.The thesis illuminates the principle and realization of AMC. After introducing the AMC principle, we analyze the coding and decoding of Turbo code and two modulate modes that is QPSK and 16QAM.Then discuss EESM mapping method which can calculate effictive SINR of OFDM subchannel, and two rules selected from AMC transmission pattern that is Block Error Rate attain requires and throughput maximum.The thesis researches the performance of AMC in the MIMO-OFDM system. By simulating, we acquire the performance curve about V-BLAST system has no AMC, V-BLAST system using AMC and V-BLAST system using AMC and precoding. Analyzing the curve, it can conclude that the system will achieve a significant gain on the throughput performance after using AMC and precoding.That is to say, AMC and precoding can improve system efficiency.更多还原