【作者】 王锋；

【导师】 刘联会；

【作者基本信息】 西安科技大学 ， 通信与信息系统， 2007， 硕士

【摘要】 信息论领域近期的研究表明,在无线通信中使用MIMO技术可以显著的提高通信的容量,并改善无线通信系统的性能,非常适合下一代移动通信系统中高速率业务的要求。在以往的多天线传输研究中,一般假定MIMO信道是独立同分布的,但在实际的多天线传输环境中,衰落往往是相关的。为此,本文对相关衰落对MIMO系统容量的影响进行了研究。要实现MIMO系统,在接收端除了需要低复杂度、高性能的检测算法外,还需要对MIMO信道进行精确的估计。由于MIMO信道的参数远多于SISO信道,复杂度明显增加,给接收机的实现带来了困难。因此,本文也对MIMO系统中的信道估计技术进行了研究。本文首先分析了MIMO系统的信道特点,研究了相关信道中的两个重要参数--天线间间距和角度扩展对信道传输矩阵的影响,给出了三种典型MIMO衰落信道的相关模型。其次,分析和仿真了SISO、MISO、SIMO和MIMO系统的平均信道容量,比较了这几种系统之间容量的差异,讨论了独立同分布和相关衰落条件下MIMO信道的容量以及采用不同功率分配方案时信道容量的变化特点。然后研究了MIMO系统的信道估计算法,给出了基于训练序列的典型信道估计算法的性能分析与仿真,实验结果表明增加训练序列数据比可以提高信道估计算法的性能。最后构建了MIMO系统实验仿真平台,在该平台下研究了相关衰落和信道估计对MIMO系统性能的影响,给出了仿真实验结果。实验结果表明该仿真平台能够对一些特定模块进行分析与测试,从而能够对各个模块中的算法、方案等作一个比较综合的性能分析比较,有助于对各个模块进行深入研究,选择或提出性能较好的算法或方案。更多还原

【Abstract】 The recent research on information theory indicates that, MIMO technology can increase the capacity of wireless communication remarkably. It’s extremely suitable for the next generation radio communication system. In the past, most research on MIMO has made the assumption that channel between antenna pairs is independent. However, in the actual wireless transmission environment, correlation usually exists in MIMO channel. In this thesis, the effect of correlation on MIMO systems is researched. To develop a MIMO system, exact channel estimation is necessary. MIMO channel estimation is more complex than SISO channel, which leads to the complexity of the receiver.Firstly, this thesis analyzes channel characteristic in MIMO system, studies the effect of two important parameters—antenna separation and angle spread in correlation channel on the channel transmission matrix, and presents three correlation models of MIMO fading channel. Secondly, the average capacity of several typical systems, such as SISO, MISO, SIMO, MIMO, is theoretically analyzed and simulated, and the relationship between the capacity and different schemes for power distributing is discussed. Thirdly, MIMO channel estimation algorithm based on pilot symbol assistance in the case of flat fading channel is researched, some simulation results are presented, and the performance of several typical methods is analyzed. The results of simulation show that enhancing the pilot data ratio in a frame can improve the performance of channel estimation algorithm. In the end, a MIMO system simulation platform is designed, and bases on this platform, the effect of correlated fading and channel estimation on the MIMO system is researched. The results of simulation show that,with the platform, each main module of MIMO system can be analyzed from the view of system, and the better approach for each module to improve the system performance can be chose.更多还原