【作者】 王琳；

【导师】 曾锋；

【作者基本信息】 中南大学 ， 软件工程， 2013， 硕士

【摘要】 摘要：随着移动用户的不断增加,人们对无线通信中的传输速率和可靠的要求也越来越高。仅仅依靠提高发射功率和增加频带宽度已经不能满足需求,由于MIMO系统可以在不增加发射功率和带宽的情况下,能够成倍的提高系统容量和信道传输的可靠性,所以引起人们的重视。无线通信系统存在多径效应,对信号传输是有害的,它引起信号传输的衰落。MIMO技术将这些由于反射和散射等原因引起的多条路径变为传送信息子流的“虚拟信道”,然后在发射端通过多个天线把信息发送出去,在接收端可用单一天线,也可用多个天线进行接收。MIMO系统的空间复用增益和空间分集增益可以显著的提高信道的容量和信道的可靠性。为解决频率选择衰落问题,出现了正交频分复用技术(OFDM)。OFDM把一个宽带信道划分成几个正交的子信道,发射端发射信号的频谱在接收端不会改变,这样每个子信道都是平坦性衰落。因此MIMO和OFDM技术相结合成为最有前途的发展技术。其中,接收端的信号检测技术对整个MIMO-OFDM系统的效率有重要影响。本文分析了MIMO系统中最大似然检测、线性检测、并行检测、干扰消除以及OR分解检测等信号检测算法,对这些算法进行了Matlab仿真,比较了算法性能和时间复杂度。重点分析了球形检测算法,并在此基础上,结合其他一些确定初始半径的方法,提出一种新的确定初始半径的方法,在不降低性能的前提下,降低了计算复杂度。最后,本文对QRD-M检测算法进行改进,应用Matlab对其性能进行仿真、分析。更多还原

【Abstract】 Abstract:In a wireless communication system, reliability and transmission rate are importance with the growing number of mobile users. Relying solely on increased transmit power and bandwidth can not meet the increasing demand. MIMO system can exponentially increase system capacity and reliability of channels without increasing the transmit power and bandwidth in the case.signal often through multiple reflections and scattering to reach the receiving end because of the presence of various obstacles, the phenomenon is multi-path effects and is harmful for signal transmission. MIMO technology use those multiple paths to transfer information. Spatial multiplexing and spatial diversity gain can significantly increase the channel capacity and channel reliability.However, MIMO systems for frequency selective fading powerless, OFDM (Orthogonal Frequency Division Multiplexing) is a technology that a channel is divided into a number of orthogonal sub-channels, each sub-channel signal bandwidth is less than the channel coherence bandwidth, so that in each sub-channel frequency selective fading can be seen as a flat fading. Therefore, the combination of MIMO and OFDM technology is important for the new Mobile, the signal detection at the receiving end is crucial for the MIMO-OFDM system’efficiency.This thesis detailed analysis of some of detection algorithm for MIMO systems,such as ML, ZF, MMSE,PD,OR etc. these algorithms are simulated with Matlab and compare their performance and algorithms complexity. Then we analysis sphere detection algorithm and proposed a new method of determining the initial radius through learn some other methods of determining the initial radius, without compromising performance, the reduction of the computational complexity. Finally, the QRD-M detection algorithm has been improved, and its performance using Matlab simulation, analysis.更多还原