多用户MIMO系统预编码技术研究

发布时间：2018-01-10 01:12

本文关键词：多用户MIMO系统预编码技术研究　出处：《南京邮电大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着无线通信技术的迅速发展，人们对通信的数据速率和通信质量有了更高层次的要求。而MIMO技术因其发送端和接收端均配置多根天线，使得系统和容量得到成倍增加，而且它还能在有限的系统带宽资源内提高频谱效率以及改善系统性能，因此MIMO技术得到迅速发展和广泛的应用，特别是应用在无线通信系统的下行链路。也正因为如此，MIMO技术已成为LTE的技术标准之一。尽管MIMO技术应用在无线通信系统中有诸多优势，但MIMO系统中也存在着一些亟需解决的问题，特别是干扰问题。例如，在MIMO系统下行链路信道中，用户接收端很难采取有效的干扰抑制技术来抑制干扰，但可以将问题转移到基站发送端来解决，基站发送端设计有效的预编码方案，再结合合理的功率分配方案，可以抑制或降低干扰，从而使得系统性能得到有效的改善。因此，预编码技术成为了研究MIMO系统干扰抑制的关键技术之一。基于上述观点，本文主要研究了多用户MIMO系统和多小区MIMO系统为了抑制干扰所采用的预编码算法和功率分配算法。首先，本文针对多用户MIMO系统中存在的用户间共信道干扰问题，采用了基于最优功率分配的最大化SLNR预编码算法，降低了共信道干扰，仿真表明，该算法比传统的BD算法和MMSE算法性能要好，且接近于SLNR迭代算法，但计算复杂度明显要低。然后，针对多用户MIMO系统每个用户存在的多数据流间干扰问题，本文采用了基于最优功率分配的两次预编码算法来消除干扰，第一次采用BD算法完全消除用户间共信道干扰，第二次采用ZF或MMSE算法用于消除用户多数据流间干扰，仿真表明，该算法明显要比只采用一次BD算法的性能要好。最后，针对多小区MIMO系统存在的小区间干扰问题，本文提出了基于最大化SLNR和最小化干扰信号的迭代算法，先通过BD算法消除每个小区内用户间共信道干扰，，然后再通过迭代优化降低小区间干扰，仿真表明，该算法在性能上要优于基于最优功率分配的BD算法和基于平均功率分配的SLNR算法。
[Abstract]:With the rapid development of wireless communication technology, people have higher requirements on data rate and quality of the communication. MIMO technology for the sender and the receiver are equipped with multiple antennas, and makes the system capacity is increased exponentially, and it can improve the spectrum efficiency in the system of limited bandwidth resources and improve the system the performance, therefore MIMO technology has been rapid development and wide application, especially in wireless communication downlink system. Because of this, MIMO technology has become one of the technical standards of LTE.
Although the application of MIMO technology has many advantages in the wireless communication system, but the MIMO system also exists some problems, especially the problem of interference. For example, in the MIMO system in the downlink channel, the receiver is difficult to take effective interference to suppress interference suppression, but the problem can be transferred to the base station transmitter to solve the transmitter design effective precoding scheme, combined with power allocation scheme is reasonable, can inhibit or reduce the interference, so that the system performance is improved. Therefore, the pre encoding technology into one of the key techniques to study MIMO system interference suppression.
Based on the above viewpoints, this paper studies the multi user MIMO system and multi cell MIMO system in order to suppress the interference using precoding and power allocation algorithms. Firstly, aiming at the existing in the multiuser MIMO system between the co channel interference, the maximum SLNR pre encoding algorithm based on the optimal power allocation. To reduce the co channel interference, simulation results show that this algorithm is better than the traditional BD algorithm and the MMSE algorithm performance is better, and close to the SLNR algorithm, but the computational complexity is significantly lower. Then, according to data users in multi user MIMO system each of the inter flow interference problem, this paper adopts two pre algorithm power allocation based on encoding to eliminate interference, first uses BD algorithm to completely eliminate the co channel interference between users, second times by ZF or MMSE algorithm is used to eliminate the interference between users of data flow, simulation This algorithm, than using only a BD algorithm for better performance. Finally, aiming at the problems of interference in multi cell MIMO system inter cell, this paper proposes an iterative algorithm for maximizing and minimizing the interference signal based on SLNR, the first through the BD algorithm to eliminate the users in each cell between the co channel interference, and then through the iterative optimization reduce inter cell interference, simulation results show that this algorithm performs better than the BD algorithm based on the optimal power allocation algorithm based on SLNR and the average power allocation.

【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.3

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