多小区3D MIMO系统波束成形方法的研究

发布时间：2018-04-01 04:36

本文选题：三维多入多出　切入点：联合传输　出处：《华北电力大学》2017年硕士论文

【摘要】：三维多入多出(3D Multiple Input Multiple Output,3D MIMO)技术作为第五代移动通信关键技术之一,受到了越来越多的关注。与传统的MIMO技术相比,3D MIMO能充分利用垂直维度的空间自由度,提升无线通信系统的传输性能,并能进一步降低小区间干扰,提高频谱效率。目前对多小区3D MIMO系统的研究还比较少,小区间的干扰问题是需要解决的一个难点。将多小区联合传输技术和3D波束成形技术应用于3D MIMO系统中,通过基站间的协作消除小区间的干扰,能够提高系统的频谱效率和能源效率。本文首先介绍了3D MIMO系统及其信道模型的建立,针对小区间的干扰问题,引出了3D MIMO联合传输技术。通过研究下行3D MIMO系统,采用迫零波束成形算法,并结合多小区联合传输方案,分析了基站天线下倾角、用户与基站之间的距离以及小区中的用户数对系统传输速率的影响。仿真结果表明,多小区联合传输相比于单小区传输在提高系统吞吐量方面具有更优的性能。其次,考虑到3D MIMO系统中较大的信息交互量,针对有限数目的反馈比特数如何在水平维度和垂直维度进行合理的分配,建立了以最小化有限反馈与理想反馈间SINR的差值为目标的优化模型,并结合对水平维度和垂直维度信道增益比值的分析,给出了特定天线配置和固定反馈比特数目条件下的最优比特分配结果。最后,在所构建的3D MIMO系统仿真环境下,针对多小区协作的场景,利用3D波束成形技术提高了用户接收到的有用信号的功率,并采用能效功率控制方法有效地抑制了小区间的干扰,提高了系统能源效率。通过仿真表明,基于3D波束成形方法的能效功率控制方案在提升系统性能方面具有很大的优越性。
[Abstract]:As one of the key technologies of the fifth generation mobile communication, 3D Multiple Input Multiple output 3D Mimo (3D MMI) technology has attracted more and more attention.Compared with traditional MIMO technology, 3D MIMO can make full use of the spatial degree of freedom of vertical dimension, improve the transmission performance of wireless communication system, further reduce inter-cell interference and improve spectral efficiency.At present, there are few researches on multi-cell 3D MIMO system, and intercellular interference is a difficult problem to be solved.Multi-cell joint transmission technology and 3D beamforming technology are applied to 3D MIMO system. The spectral efficiency and energy efficiency of the system can be improved by eliminating intercellular interference through the cooperation between base stations.In this paper, the establishment of 3D MIMO system and its channel model is introduced firstly. Aiming at the intercellular interference, the 3D MIMO joint transmission technology is introduced.By studying the downlink 3D MIMO system, using zero-forcing beamforming algorithm and combining with the multi-cell joint transmission scheme, the influence of the base station antenna downdip angle, the distance between the user and the base station and the number of users in the cell on the transmission rate of the system are analyzed.The simulation results show that multi-cell joint transmission has better performance than single-cell transmission in improving system throughput.Secondly, considering the large amount of information exchange in 3D MIMO system, how to allocate the finite number of feedback bits in horizontal dimension and vertical dimension is reasonable.An optimization model with the objective of minimizing the difference between finite feedback and ideal feedback is established, and the channel gain ratio between horizontal dimension and vertical dimension is analyzed.The optimal bit allocation results for a given antenna configuration and a fixed number of feedback bits are given.Finally, in the simulation environment of 3D MIMO system, 3D beamforming technology is used to improve the power of the useful signals received by the user.The energy efficiency power control method is used to effectively suppress the interference between the cells and improve the energy efficiency of the system.Simulation results show that the energy efficiency power control scheme based on 3D beamforming has great advantages in improving system performance.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.3

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