非正交多址系统中下行链路预编码技术研究

发布时间：2018-03-05 04:07

本文选题：多输入多输出技术　切入点：非正交多址　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：随着现代信息社会的飞速发展,高速率移动多媒体业务成为除传统语音和低速率数据传输业务之外最主要的移动通信业务之一。为了应对高速增长的移动数据流量,第五代(5G)移动通信系统面临着众多挑战,这些挑战包括,在有限的频谱资源下提供更好的用户体验,更高的数据传输速率,以及更优的用户服务质量。而在这些挑战中,最关键的在于提高通信系统的频谱利用率。近年来,已有的大量研究表明,使用多输入多输出(MIMO,Multiple Input Multiple Output)技术可以提高系统频谱效率,改善系统通信质量。在假设信道状态信息(Channel State Information,CSI)已知的条件下,采用合适的预编码方法,可以使系统的性能得到进一步的提升。另一方面,不同于传统的正交多址技术(Orthogonal Multiple Access,OMA),采用非正交多址(Non-Orthogonal Multiple Access,NOMA)技术可以进一步的提高系统的频谱利用率,因此也受到了研究人员的广泛关注,并被认为是5G系统中富有前景的多址技术之一。本文以5G的应用需求为背景,结合目前两大可以提升频谱效率的主流技术,MIMO技术和NOMA技术,研究MIMO广播信道(BC,Broadcast Channels)系统的预编码策略及其低复杂度实现算法。具体研究工作可以概括如下:1)在误符号率(SER,Symbol Error Rate)性能的约束下,研究两用户MIMO BC系统的预编码优化设计。首先利用格理论(Lattice Theory)和递归构造的思想,设计MIMO单播系统的最小欧氏距离(MED,Minimum Euclidean Distance)预编码器;然后,结合 GSVD(Generalized Singular Value Decomposition)和交替优化的思想,将MIMO单播系统的MED预编码算法扩展到两用户MIMO BC系统中,得到两用户MIMO BC系统的NOMA-MED预编码器。2)在可达传输速率性能的约束下,研究两用户MISO(Multiple Input Single Output)BC系统的预编码优化设计。首先,基于优化对偶理论,设计两用户MISO系统的最优NOMA预编码器,并分析研究其性质和性能;其次,通过分析对比两用户MISO BC的最优NOMA预编码和DPC(Dirty Paper Coding)预编码的性能,提出准退化信道(Quasi-Degradation)的概念;再次,基于准退化的概念和性质,设计两用户MISO BC系统的低复杂度H-NOMA预编码器(Hybrid NOMA Precoder);最后,深入分析H-NOMA预编码器的性能,并与最优NOMA预编码器以及传统的ZFBF(Zero-Forcing Beamforming)和 DPC 比较。3)分别在SER性能和可达传输速率性能的约束下,研究多用户混合多址MIMO BC系统的预编码优化设计。在混合多址系统中,用户被分成多个小簇,簇内采用NOMA技术,而簇间采用OMA技术来消除簇间干扰。分别在给定所有用户的最低传输速率约束和最差SER性能约束的条件下,以最小化总发射功率为目标,设计混合多址MIMO BC系统的预编码策略。本工作的主要内容包括以下两个方面,其一是,针对基于SER性能约束的预编码器设计问题,在簇内采用两用户MIMOBC系统的NOMA-MED预编码器,通过研究相应的用户配对算法,得到多用户混合多址MIMO BC系统的预编码方法;其二是,针对基于传输速率约束的预编码器设计问题,在簇内采用两用户MISOBC系统的H-NOMA预编码器,通过研究用户配对算法,得到多用户混合多址MISO BC系统的预编码方法。
[Abstract]:With the rapid development of modern information society, high-speed mobile multimedia services become the traditional voice and low rate data transmission business outside the main business of mobile communication. In order to cope with the rapid growth of mobile data traffic, the fifth generation (5G) mobile communication system is facing many challenges. These challenges include, to provide a better user experience in the limited spectrum, high data rate, and better quality of service. And in these challenges, the most important is to improve the spectral efficiency of the communication system. In recent years, there have been a number of studies have shown that the use of multiple input multiple output (MIMO, Multiple Input Multiple Output) technology can improve the system spectral efficiency, improve the quality of communication system. On the assumption that the channel state information (Channel State, Information, CSI) under the condition of knowing the appropriate precoding method, can In order to make the performance of the system has been further improved. On the other hand, orthogonal multiple access technology is different from the traditional (Orthogonal Multiple Access, OMA), using the non orthogonal multiple access (Non-Orthogonal Multiple, Access, NOMA) technology can improve the spectrum utilization rate of the system further, so it has been attracting the attention of researchers, and is considered to be one of the most promising multiple access technology in 5G system. Based on the background of the 5G application demand, combined with the current mainstream technology two can enhance the spectral efficiency, MIMO technology and NOMA technology, the research of MIMO broadcast channel (BC Broadcast, Channels) system precoding strategy and low complexity algorithm. The research work can be summarized as follows: 1) the symbol error rate (SER, Symbol Error Rate) performance under the constraints of the two user MIMO BC system precoding optimization. First using lattice theory (Lattice Theor Y) and recursive construction theory, the minimum Euclidean distance of the unicast system design of MIMO (MED, Minimum Euclidean Distance) precoder; then, combined with GSVD (Generalized Singular Value Decomposition) and alternating optimization theory to extend MED encoding algorithm MIMO unicast system to two users of MIMO BC system,.2 NOMA-MED encoder two user MIMO BC system) in the transmission rate up to the performance constraints of two users of MISO (Multiple Input Single Output) BC system precoding optimization. Firstly, based on the theory of dual optimization, optimal NOMA precoder design two user MISO system, and studies its properties and performance; secondly, through the optimal pre NOMA encoding and DPC comparative analysis of two user MISO BC (Dirty Paper Coding) performance of the pre encoding, the quasi degenerate channel (Quasi-Degradation) concept; thirdly, based on the quasi degenerate The concept and properties of low complexity H-NOMA precoder design two user MISO BC system (Hybrid NOMA Precoder); finally, in-depth analysis of the performance of H-NOMA precoder, and the optimal NOMA precoder and the traditional ZFBF (Zero-Forcing Beamforming) and DPC.3) respectively in SER performance and transmission rate up to performance constraints under the research of multi user multiple access MIMO BC system precoding optimization design. In the hybrid multiple access system, the user is divided into a plurality of small clusters, using NOMA technology in the cluster and inter cluster using OMA technology to eliminate inter cluster interference. In the minimum transmission rate constraint for all users and worst SER the performance constraints, to minimize the total transmission power as the goal, the design of hybrid multiple access MIMO BC system precoding strategy. The main contents of this work include the following two aspects, one is that the performance constraint based on SER The precoder design problem using the NOMA-MED precoder two user MIMOBC system within the cluster, through the study of the corresponding user pairing algorithm, multi user multiple access MIMO BC system precoding method; secondly, according to the transmission rate constraint based precoder design problem using the H-NOMA precoder two user MISOBC system in the cluster, through the study of user pairing algorithm, multi user multiple access MISO BC system precoding method.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN929.5

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