MIMO系统中的干扰处理技术研究

发布时间：2018-03-25 16:28

本文选题：多输入多输出　切入点：预编码　出处：《北京邮电大学》2014年博士论文

【摘要】：随着多媒体业务和宽带因特网业务迅速发展,无线用户数量快速增长,人们对无线数据业务的要求越来越高。然而由于频谱资源的有限性,无线通信系统面临越来越严重的干扰。为了提高无线通信系统的有效性和可靠性,多小区、多用户MIMO是无线通信研究的重点课题之一。本文对多输入多输出(Multiple Input Multiple Output, MIMO)系统中的干扰处理技术进行了深入的研究,针对各场景设计了相应的干扰处理方案,有效地提高了无线通信系统的容量,降低了误码率。本文的主要工作及创新成果如下： (1)为了提高多小区MIMO下行信道和多用户MIMO干扰信道中无线通信的有效性和可靠性,本文对空时分集的干扰对齐技术进行了研究,分别提出了多小区中空时分集的干扰对齐方案和MIMO干扰信道中空时分集的干扰对齐方案,所提两个方案结合具体的场景,在不同时隙分别采用不同的干扰对齐方法,将每个用户的等效信道转变为等效时变信道,由此将空间分集转换为等效信道的时间分集,并结合空时处理技术,获得了分集增益。理论分析和仿真验证,所提方案与原有方案相比,在获得相同自由度的同时获得了更高的分集增益,有效地降低了系统的误码率,提高了系统的可靠性。 (2)针对MIMO异构网络中的分层干扰对齐方案在低信噪比条件下容量较小的问题,本文提出了一种加权最小均方误差的规则化干扰对齐方案,所提方案利用分层干扰对齐方案的信道增益作为加权矩阵,通过迭代优化预处理和后处理矩阵,实现了干扰的消除和功率的分配。理论分析和仿真表明,所提方案能通过少量迭代迅速收敛,提高了整个信噪比范围内系统的容量。 (3)为了进一步提高多小区MIMO下行传输的有效性和可靠性,本文针对非线性的干扰对齐方案进行了研究,提出了一种多小区多用户THP(Tomlinson-Harashima Precoding)的干扰对齐方案,并给出了所提方案的设计准则,所提方案利用THP构造多小区传输模型,通过设计合适的反馈三角矩阵、前馈矩阵和后处理矩阵,实现了干扰对齐,从而有效地提升了各小区的容量,降低了误码率。理论分析及仿真验证,与已有干扰对齐方案相比,所提方案可以获得更大的容量和更低的误码率。 (4)干扰对齐技术可以有效提高MIMO X中继系统传输的自由度,然而为了实现完全的干扰对齐,用户需要配置较多的天线。为了提高MIMO X中继系统中在用户天线数较小情况下的容量,本文针对MIMO X中继系统提出了一种部分干扰对齐传输方案,推导出了MIMO X中继部分干扰对齐的可行性条件,并给出了一种迭代的实现算法,所提算法能灵活适应各种用户和中继天线配置,可以有效地提高系统传输的自由度。仿真结果验证了所提方案的有效性。 (5)为了提高MIMO多向中继系统的容量,本文研究了MIMO多向中继的并行传输,提出了一种多向中继非对称传输方案,所提方案通过建立一个新的多向中继传输模型,采用多天线并行非对称发送和接收多流数据,设计相应的预处理矩阵及迫零检测矩阵消除干扰,在不增加中继天线数的前提下,实现了多向中继的并行非对称传输。本文推导出了所提方案的系统容量,理论分析和仿真结果表明,所提方案能有效地降低了中继的能耗,提高了传输效率,在多组传输时进一步降低了对中继天线数的要求。
[Abstract]:With the rapid development of multimedia services and broadband Internet services, the rapid growth in the number of wireless users, the wireless data services have become increasingly demanding. However, due to the limited spectrum resources, wireless communication system is facing more and more serious interference. In order to improve the effectiveness and reliability of wireless communication systems, multi area, multi user MIMO is one of the the key issue in wireless communication research.
Based on multiple input multiple output (Multiple Input Multiple Output, MIMO) interference processing technology in the system is studied, according to the scene design the interference of appropriate treatment, can effectively improve the capacity of wireless communication systems, reduce the bit error rate. The main work and innovation are as follows:
(1) in order to improve the effectiveness of wireless communication in multi cell downlink MIMO and multi-user MIMO channel interference and reliability, interference alignment technique based on space-time diversity were studied, respectively, proposed interference alignment scheme for multi cell space-time diversity interference alignment scheme and space-time MIMO interference channel diversity, the the two scheme combined with the specific scene, using interference alignment method in different time slots, the equivalent channel of each user into equivalent time-varying channel, which will be converted to equivalent spatial diversity time diversity channel, combined with space-time processing technology, obtain diversity gain. Theoretical analysis and simulation verification, the proposed and compared to the original program, obtain higher diversity gain in the same degree of freedom at the same time, effectively reduce the error rate of the system, improve the reliability of the system.
(2) according to the hierarchical interference alignment scheme in MIMO network in the condition of low SNR small capacity problem, this paper proposes a weighted least mean square error rule of interference alignment scheme, the proposed scheme using hierarchical channel gain interference alignment scheme as the weighting matrix, by optimizing the pretreatment and after the distribution of matrix interference and power. Theoretical analysis and simulation results show that the proposed scheme can converge quickly through several iterations to improve the signal-to-noise ratio within the range of the capacity of the system.
(3) in order to further improve the effectiveness of the multi cell MIMO downlink transmission and reliability, this paper studies the nonlinear interference alignment scheme was put forward, a multi cell multi user THP (Tomlinson-Harashima Precoding) of the interference alignment scheme, and gives the proposed design criterion scheme, the proposed scheme is constructed using THP multi cell the transmission model, through the design of appropriate feedback triangular matrix, feedforward matrix and postprocessing matrix, realize interference alignment, so as to effectively improve the capacity of each cell, which reduces the error rate. Theoretical analysis and simulation results, compared with the existing interference alignment scheme, the bit error rate of the proposed scheme can obtain larger capacity and lower.
(4) interference alignment technology can effectively improve the MIMO X relay transmission system degrees of freedom, but in order to achieve interference alignment completely, antenna users need to configure more users. In order to capacity in the condition of small number of antennas to improve MIMO X relay system, according to the MIMO X relay system presents a partial interference alignment transmission scheme, deduced the feasibility conditions of MIMO X relay interference alignment, and gives the realization of iterative algorithm, the proposed algorithm can flexibly adapt to the configuration of various users and relay antennas, can effectively improve the system transmission freedom. The simulation results verify the effectiveness of the proposed scheme.
(5) in order to improve the capacity of MIMO multi relay system, this paper studies the parallel transmission of multi MIMO relay, proposes a multi relay asymmetric transmission scheme, the proposed scheme through the establishment of a new multi relay transmission model, using multiple antennas parallel non symmetric sending and receiving multi stream data, the design of preconditioning matrix zero forcing detection to eliminate the interference matrix and the corresponding, without increasing the number of relay antennas, realizes parallel asymmetric transmission of multi relay. This paper proposed the system capacity scheme, theoretical analysis and simulation results show that the proposed scheme can effectively reduce the energy consumption of the relay transmission is improved. In the groups of transmission efficiency, further reduce the number of relay antennas.

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

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