摘要在接收端采用多元天线来获得接收分集，发射端仍然采用一个阵元的的单输入多输出系统，和在发射端采用阵列结构而接收天线采用单天线结构的多输入单输出系统，两种系统相结合，即接收端和发射端同时采用阵列天线的系统就是多输入多输出（multiple input multiple output即MIMO）系统。84608

它具备以下几个特点:第一能利用或减轻多径衰落，MIMO技术能够充分采用多径的各种发射/合成技术，提高通信系统的性能。第二MIMO系统内容能够采用自适应波束形成技术或者多用户检测技术多共道干扰进行有效的的抑制和消除。第三MIMO技术能够提高频谱利用率，提高发射效率，减小发射功率，减小空间电磁干扰以及增大系统容量，而且还能减小对生态环境的影响。

本文主要研究了MIMO系统的信道模型，信号在无线信道传输中会遇到各种衰落问题，所以信道的研究可以为我们接下来的研究奠定基础。其次我找出最大似然（ML)、迫零检测（ZF)、最小均方误差检测（MMSE)和改进的MMSE-SIC检测算法这四种较为传统的信号检测算法，研究他们的原理以及各自的性能优劣，最后基于MATLAB仿真平台，对这几种算法进行仿真制图，在不同的条件下对他们的性能以仿真图的方式进行观察和分析。

毕业论文关键词：多输入多输出；信号检测；最大似然 

Abstract At the receiving end using multiple antennas to obtain receive persity, the transmitting end is still a single-input multi-output system a picket of, and at the transmitter uses an array structure and receiving antennas using multiple-input single-output system single antenna structure, two systems combined, namely receiving end and the transmitting end while using an array antenna system is a MIMO (multiple input multiple output that is MIMO) system。

It has the following characteristics: first they can use or mitigate multipath fading, MIMO technology can fully use the various multipath transmission / synthesis technology to improve the performance of the communication system。 Content second MIMO system can employ adaptive beamforming technology or multi-user detection technology and more effective co-channel interference suppression and elimination。 The third MIMO technology can improve the spectrum utilization, improve emission efficiency, reduce transmission power to reduce the space electromagnetic interference and increase system capacity, but also reduce the impact on the ecological environment。

This paper studies the MIMO channel model system, the signal transmission in the radio channel fading encounter various problems, the study channel may lay the foundation for our next study。 Secondly, I find the maximum likelihood (ML), zero forcing detection (ZF), minimum mean square error detection (MMSE) and improved MMSE-SIC detection algorithm four more traditional signal detection algorithms and study their respective principles performance will last based on MATLAB simulation platform, these different kinds of mapping algorithm simulation under different conditions for their performance to simulate FIG manner were observed and analyzed。

Keywords: Multiple input multiple output(MIMO)；signal detection ；maximum likelihood

目录

第一章 绪论 1

1。1研究背景和意义 1

1。2国内外研究现状 2

1。3论文结构与主要内容 3

第二章 空间复用MIMO系统理论基础 4

2。1空间复用MIMO技术概述 4

2。 2 MIMO系统信道模型 5

2。2。1路径衰落