【作者】 刘琳；

【导师】 田红心；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2010， 硕士

【摘要】 MIMO技术由于能够显著提高信道容量而成为无线通信关键技术的一大研究热点。基于TDD技术的MIMO系统能够利用信道互易性,直接为发端提供信道状态信息(CSI),而不需要采取反馈措施,节省了额外的系统开销。但是实际情况下,由于上下行链路引入的干扰不同,这种信道互易性会遭到破坏。本文针对存在邻小区干扰和多用户干扰的TDD MIMO系统,研究干扰对TDD MIMO信道互易性的影响以及联合干扰抑制方法。具体内容如下:1.建立了单链路MIMO-OFDM系统模型,并对系统中关键技术,如预编码、注水原理进行详细分析;研究了仿真中用到的信道模型SCM-E,对仿真中的几种环境进行了介绍;2.以SCM-E信道模型为基础,建立了多小区多用户TDD MIMO系统模型,并分析了上下行链路中的干扰形式;3.通过系统容量公式推导,分析了干扰对TDD MIMO系统互易性的影响,并在不同的仿真场景中进行了验证,理论分析和仿真表明干扰会破坏TDD MIMO信道互易性,严重影响系统性能;4.在已有的干扰抑制算法基础上,给出一种邻小区干扰和多用户干扰的联合抑制算法,并在不同的仿真环境下进行了验证,仿真结果表明,该算法能在多小区多用户环境中有效抑制干扰,并且减少了反馈的环节。更多还原

【Abstract】 There has been considerable recent interest in MIMO system, due to its potential for significant gain in channel capacity. By using channel reciprocity in time division duplex (TDD) MIMO systems, channel state information (CSI) was directly provided to BS, which reduced the additional system overhead. But in fact,channel reciprocity was destroyed because of unsymmetrical interference between uplink and downlink. To solve this problem,the impact of interference on the channel reciprocity of TDD-MIMO systems was analyzed. The main contributions are as follows:1 Simulation model of single-link MIMO-OFDM systems are built, and the key technologies in the system such as precoding and water flooding are analyzed in detail. 3GPP spatial channel model is studied and several environments used in simulation are introduced.2 Simulation model of multi-cell multi-user systems are built based on SCM-E channel model. Difference of interference between uplink and downlink in the previous models was compared.3 System capacity is derived and verified in different simulation scenarios. Simulation results show that interference destroys the channel reciprocity and degrades the system capacity of TDD-MIMO systems.4 A new interference suppression algorithm is given, which is used to suppress inter-cell interference and intra-cell interference. Its performance is simulated in different environments. Simulation results show that, interference can be suppressed effectively by the proposed algorithm without any feedback for the transmitter.更多还原