WiFi系统中MU-MIMO传输接入技术研究
发布时间：2018-08-12 21:03
【摘要】：无线通信在人们的生活中几乎无处不在。Wifi在人类生活中更是扮演着不可替代的角色。2004年,IEEE802.11n标准中加入了MIMO技术。在MIMO技术中,接收信号的检测技术,是衡量通信系统性能的重要指标。而良好的通信系统性能要求检测算法具有计算复杂度低且误码率性能好的特点。所以如何对MIMO接收信号进行检测,并且怎样对检测算法的性能进行提升变得尤为重要。在IEEE802.11标准中,另一个影响无线局域网性能的重要因素就是接入技术。因此接入技术的研究对无线网络性能的提升起着关键性的作用。本文首先针对MIMO检测算法,先详细介绍了已有的几种基本MIMO检测算法,对文献中已有的基于SIC的多反馈MIMO检测算法进行了分析和仿真。在多反馈算法中使用阴影区域约束,干扰消除中通过引入星座点作为解决判决来解决反馈环路中的误差传播问题。在多反馈算法地基础上,研究了一种多反馈改进算法,算法使用了递归的方法,减少了误差传播,提高了误码性能。其次针对多用户接入技术,研究了多用户MIMO接入方案,对方案进行了理论分析。对相应的控制帧进行改进,使用基于马尔科夫链的分析模型来评估所提出的方案的性能。结果显示系统性能明显优于单用户传输。在CSMA/CA的基础上,研究了一种异步多用户接入方案。方案允许一个信道下同时接入多个用户,并对涉及到的帧格式进行了改进,详细阐述了方案的流程并对吞吐量性能进行了仿真。对比了异步多用户接入方案和多用户MIMO接入方案的吞吐量性能,结果显示异步接入方案的性能要优于上行多用户MIMO传输方案。
[Abstract]:Wireless communication is almost everywhere in human life. Wifi plays an irreplaceable role in human life. In 2004, IEEE 802.11n standard added MIMO technology. In MIMO technology, the detection technology of received signal is an important index to measure the performance of communication system. The good performance of communication system requires that the detection algorithm has the characteristics of low computational complexity and good bit error rate (BER) performance. So how to detect the received signals of MIMO and how to improve the performance of the detection algorithm become more important. In the IEEE802.11 standard, another important factor affecting the performance of WLAN is access technology. Therefore, the research of access technology plays a key role in improving the performance of wireless networks. In this paper, several basic MIMO detection algorithms are introduced in detail for MIMO detection algorithms, and the existing multi-feedback MIMO detection algorithms based on SIC in literature are analyzed and simulated. Shadow region constraints are used in multi-feedback algorithms, and constellation points are introduced to solve the error propagation problem in feedback loop in interference cancellation. On the basis of multi-feedback algorithm, a multi-feedback improved algorithm is studied, which uses recursive method to reduce error propagation and improve error performance. Secondly, the multi-user MIMO access scheme is studied, and the scheme is analyzed theoretically. The corresponding control frame is improved to evaluate the performance of the proposed scheme using Markov chain based analysis model. The results show that the performance of the system is better than that of single user transmission. Based on CSMA/CA, an asynchronous multi-user access scheme is studied. The scheme allows multiple users to be accessed simultaneously in a single channel and improves the frame format involved. The flow of the scheme is described in detail and the throughput performance is simulated. The throughput performance of asynchronous multi-user access scheme and multi-user MIMO access scheme is compared. The results show that the performance of asynchronous access scheme is better than that of uplink multi-user MIMO transmission scheme.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.3;TN92
本文编号：2180361
[Abstract]:Wireless communication is almost everywhere in human life. Wifi plays an irreplaceable role in human life. In 2004, IEEE 802.11n standard added MIMO technology. In MIMO technology, the detection technology of received signal is an important index to measure the performance of communication system. The good performance of communication system requires that the detection algorithm has the characteristics of low computational complexity and good bit error rate (BER) performance. So how to detect the received signals of MIMO and how to improve the performance of the detection algorithm become more important. In the IEEE802.11 standard, another important factor affecting the performance of WLAN is access technology. Therefore, the research of access technology plays a key role in improving the performance of wireless networks. In this paper, several basic MIMO detection algorithms are introduced in detail for MIMO detection algorithms, and the existing multi-feedback MIMO detection algorithms based on SIC in literature are analyzed and simulated. Shadow region constraints are used in multi-feedback algorithms, and constellation points are introduced to solve the error propagation problem in feedback loop in interference cancellation. On the basis of multi-feedback algorithm, a multi-feedback improved algorithm is studied, which uses recursive method to reduce error propagation and improve error performance. Secondly, the multi-user MIMO access scheme is studied, and the scheme is analyzed theoretically. The corresponding control frame is improved to evaluate the performance of the proposed scheme using Markov chain based analysis model. The results show that the performance of the system is better than that of single user transmission. Based on CSMA/CA, an asynchronous multi-user access scheme is studied. The scheme allows multiple users to be accessed simultaneously in a single channel and improves the frame format involved. The flow of the scheme is described in detail and the throughput performance is simulated. The throughput performance of asynchronous multi-user access scheme and multi-user MIMO access scheme is compared. The results show that the performance of asynchronous access scheme is better than that of uplink multi-user MIMO transmission scheme.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.3;TN92
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