MIMO系统的信道容量分析.docVIP

PAGE PAGE I 摘 要 MIMO技术是无线通信技术发展的一次重大飞跃，它能够突破无线频率资源限制，大幅度提高无线通信系统效率，被认为是无线通信技术未来发展的方向。然而，MIMO技术也彻底打破传统的无线通信模式，它要求系统使用多根发射和接收天线同时地发射和接收数据，使得无线通信系统结构、分析方法、调制、编码、信道估计、检测和多址方式等各个方面面临挑战。本文在国内外相关研究工作的基础上，针对MIMO信道容量理论进行深入研究。首先介绍了MIMO的研究现状，包括已取得的进展和存在的问题。并在移动无线信道特点的基础上，阐述了MIMO信道的特征，建立了数学模型。然后，仿真了数种典型恒定信道参数系统的容量以及空间相关性对信道容量的影响，进而得出结论：MIMO系统可以有效的提高信道容量, 但是由于天线之间相关性的影响，MIMO系统容量也有所下降。其次，分析了STBC系统的容量，并将其与全开环MIMO系统的容量进行了比较。最后重点实现了OFDM技术的仿真，并讨论了MIMO-OFDM系统在频率选择性信道下的容量以及多径和空间相关对其系统容量的影响。 关键词： 多输入多输出 信道容量 空间相关性 空时分组码 正交频分复用 Abstract Multiple-input-multiple-output(MIMO) technology is a significant breakthrough in the development of wireless communication technologies. It can get rid of the constraint of radio frequency resource and greatly increase the spectral efficiency of wireless systems, and thus is considered as the future development trend of wireless communication technologies. However, MIMO technology thoroughly breaks the mode of traditional wireless communications, since it requires multiple transmit and receive antennas to simultaneously transmit and receive data information in the same time, which challenges all the aspects of wireless communications including system architecture, analytical methods, modulation, coding, detection, channel estimation, multiple access, and so on. On the basis current research works, this paper investigates MIMO channel capacity . Firstly, the author introduces the current study of MIMO, include the inprovements which were received and the challenges which are faceing to. Then, it analyses the wireless channels, and expounds the MIMO channel characteristic, and models the MIMO channel . Secondly, it simulates the capacity of several typical invariableness parameter channels and the impact of channel space correlation on the capacity of MIMO system . From the simulation, we can take the conclusion that MIMO system can effictively improve thannel is decreased. Thirdly, it analyzes the capacity of STBC system , then comparises the