大规模MIMO多对双向中继系统性能分析

发布时间：2018-03-01 00:02

本文关键词： 大规模多输入多输出系统多对双向中继硬件失真信道估计误差全双工　出处：《北京交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：第四代(4th generation,4G)移动通信系统已经大规模商用。目前世界各国都在大力研究第五代(5th generation,5G)移动通信系统。为了满足5G极高的性能指标,大规模MIMO(Massive Multiple-Input Multiple-Output)作为可以极大提高系统容量的关键技术之一被广泛研究。大规模MIMO通过部署成百上千根天线,在同一频谱资源上同时传输多路信号,可以有效利用稀缺而宝贵的频带资源,大幅度提升系统容量。另一方面,物联网作为5G重要的应用场景之一,不仅需要极大的系统容量,并且需要支持海量设备同时通信。所以,大规模MIMO多对双向中继(Multi-pair Two-way Relay)系统凭借其允许多组设备同时通信以及系统容量高等特点,符合5G物联网海量连接与通信的需求,是目前5G物联网的研究热点。本文首先针对大规模MIMO成本过高问题,提出基于低成本射频链路的大规模MIMO半双工多对双向中继系统架构。针对低成本射频链路引入的硬件失真(Hardware Impairment)问题,分析其对系统频谱和能量效率的影响,并基于大数定理推导出天线数量趋近于无穷时该系统频谱和能量效率的近似闭式表达式,得到使能量效率最优的天线数和设备对数。另外,本文提出了该场景下的硬件缩放定律(Hardware Scaling Law),证明可以通过部署多根低成本的天线节约硬件成本而系统性能没有损失。然后,针对实际场景中难以获取准确的信道状态信息问题,提出基于硬件失真的大规模MIMO半双工多对双向中继系统信道估计误差模型。研究证明系统频谱效率与能量效率会随着信道估计误差的增加而降低。该场景下的硬件缩放定律证明,信道估计误差会增加硬件部署成本,中继需要部署更多的天线才能使系统性能没有损失。最后,为了进一步满足5G物联网对系统容量的需求,本文提出基于硬件失真的大规模MIMO全双工多对双向中继系统架构。研究证明,全双工系统能显著提高系统的频谱效率与能量效率。但是,当全双工系统引入的环路干扰(Loop Interference)较为严重时,系统将失去时间效率优势,其性能反而低于半双工系统。同时,本文证明了全双工系统拥有与半双工系统相同的硬件缩放定律。综上所述,本文分析了天线数量、设备数量、信道衰落、硬件失真度、信道估计误差以及环路干扰等参数对大规模MIMO多对双向中继系统性能的影响,为实际系统设计提供理论指导。研究表明,该系统可提高5G物联网海量连接与通信场景高速数据传输能力。
[Abstract]:The 4th generation 4th Generation 4G) mobile communication system has been widely used. At present, all countries in the world are making great efforts to study the 5th Generation Generation 5G mobile communication system. In order to meet the extremely high performance index of 5G, Large-scale MIMO(Massive Multiple-Input Multiple-Output has been widely studied as one of the key technologies that can greatly improve the system capacity. Large-scale MIMO transmits multiple signals simultaneously over the same spectrum resource by deploying hundreds of antennas. On the other hand, as one of the important application scenarios of 5G, the Internet of things not only needs great system capacity, Therefore, the large scale MIMO multi-pair multi-pair Two-way Relay system, which allows multiple sets of devices to communicate at the same time and has high system capacity, meets the needs of mass connectivity and communication in the 5G Internet of things. 5G Internet of things is a hot research topic. Firstly, this paper aims at the problem of high cost of large-scale MIMO. This paper presents a large scale MIMO half-duplex multi-pair bidirectional relay system architecture based on low cost RF link. Aiming at the problem of hardware distortion introduced by low cost RF link, this paper analyzes its influence on the spectrum and energy efficiency of the system. Based on the large number theorem, an approximate closed-form expression of the frequency spectrum and energy efficiency of the system is derived when the antenna number approaches infinity, and the number of antennas and the logarithm of the equipment are obtained to optimize the energy efficiency. In this paper, the hardware scaling law and hardware Scaling law in this scenario are presented. It is proved that the hardware cost can be saved by deploying multiple low-cost antennas without loss of system performance. Then, it is difficult to obtain accurate channel state information in practical scenarios. A large scale MIMO half-duplex multi-pair channel estimation error model based on hardware distortion is proposed. It is proved that the spectral efficiency and energy efficiency of the system decrease with the increase of channel estimation error. The laws of scaling prove that, Channel estimation error will increase the cost of hardware deployment, and the relay will need to deploy more antennas to make the system performance without loss. Finally, in order to further meet the 5G Internet of things system capacity requirements, In this paper, a large scale MIMO full-duplex multi-pair bidirectional relay system architecture based on hardware distortion is proposed. It is proved that the full-duplex system can significantly improve the spectral efficiency and energy efficiency of the system. When the loop interference introduced into the full-duplex system is more serious, the system will lose the advantage of time efficiency, and its performance will be lower than that of the half-duplex system. In this paper, we prove that the full-duplex system has the same law of hardware scaling as the half-duplex system. In summary, we analyze the number of antennas, the number of devices, the channel fading, the hardware distortion. The influence of parameters such as channel estimation error and loop interference on the performance of large scale MIMO multi-pair two-way relay system provides theoretical guidance for practical system design. This system can improve 5 G Internet of things mass connection and communication scene high speed data transmission ability.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.3

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