论文总字数：25034字

摘 要

第五代移动通信（5G）建设不仅仅是对当前网络结构的简单升级与进化，更加是通信与信息科技领域的一次革命。第五代移动通信技术将会给每位用户，每个终端（自感知设备，信息物理系统）有效的提供更加安全，可靠的，低延迟的服务。5G关键能力比以前几代移动通信更加丰富，用户体验速率、连接数密度、端到端时延、峰值速率和移动性等都将成为5G的关键性能指标。然而，与以往只强调峰值速率的情况不同，业界普遍认为用户体验速率是5G最重要的性能指标，它真正体现了用户可获得的真实数据速率，也是与用户感受最密切的性能指标。基于5G主要场景的技术需求，5G用户体验速率应达到Gbps量级。面对多样化场景的极端差异化性能需求，5G很难像以往一样以某种单一技术为基础形成针对所有场景的解决方案。此外，当前无线技术创新也呈现多元化发展趋势，除了新型多址技术之外，大规模天线阵列、波束赋形技术、超密集组网、全频谱接入、新型网络架构等也被认为是5G主要技术方向，均能够在5G主要技术场景中发挥关键作用。

大规模MIMO技术与新型多址技术的结合是未来5G系统的根本技术之一，由于用户间干扰、信道噪声的影响，为了满足用户QOS需求，在大规模MIMO基站发射端加上波束赋形技术，可以大大改善接收端的信噪比。

链路自适应是提高通信性能和系统利用率的有效办法，通过自动调整发射机的参数来克服信道环境的改变，从而获得最优通讯效果。无线信道的主要特点就是其开放的链路和链路时变特性，并且移动用户的增加和各用户不同的服务需求也增大了环境的复杂性和随机性。因此通过反馈，动态的调制发射端波束成形矩阵参数，可以使得系统的性能得到进一步的提升。

关键词：5G；大规模MIMO；波束赋形；链路自适应技术；预编码；建模与仿真。

Abstract

The article is mainly about the foundation of the fifth generation of wireless commuunication.Fifth generation mobile communication (5 g) construction is not only a simple upgrade to the current network structure and evolution, more is a revolution in the field of communications and information technology.Fifth generation mobile communication technology will give each user, each terminal (physical self-sensing equipment, information systems) effectively provide more secure, reliable, low latency.5 g key ability to generations of mobile communications more rich than before, the user experience rate, the density of the number of connections, end-to-end delay, peak rate and mobility will be 5 g key performance indicators (kpis)., however, is different with the past only emphasize the peak rate, rate of the industry generally believe that the user experience is the most important performance index of 5 g, it truly reflects the users can obtain the true data rate, but also the most closely with the user feel performance metrics.Based on the technical requirement of 5 g scene mainly rate should achieve Gbps magnitude 5 g the user experience.In the face of diverse scenarios extreme differentiation performance requirements, 5 g hard as usual on the basis of a single technology form solutions for all scenarios.In addition, the current wireless technology innovation also presents the diversified development trend, in addition to the new multiple access technology, large-scale antenna array, the beam informs technology, super dense network, full spectrum access, a new network architecture is also thought to be main technical direction, 5 g all can in 5 g major technology play a key role in the scene.
Multi-input multi-output (MIMO) technology and the new multiple access technology combined with mass is one of the fundamental technology of the future 5 g system, due to the interference between users, the influence of channel noise, in order to satisfy the user's QOS requirements, in large-scale MIMO base station transmitting terminal and beam with vehicle technology, can greatly improve the signal-to-noise ratio at the receiving end.
Link adaptive is a effective way to improve communication performance and system utilization, by automatically adjusting the parameters of the transmitter to overcome the change of the channel environment, and obtain the optimal communication effect.The main characteristics of wireless channel is its link and link time-varying characteristic of open, and the increase of mobile users and the users of different service demand also increases the environmental complexity and randomicity.So by feedback, dynamic modulation transmitter beam forming matrix parameters, can get further improve performance of the system.Fifth generation mobile communication (5 g) construction is not only a simple upgrade to the current network structure and evolution, more is a revolution in the field of communications and information technology.Fifth generation mobile communication technology will give each user, each terminal (physical self-sensing equipment, information systems) effectively provide more secure, reliable, low latency.5 g key ability to generations of mobile communications more rich than before, the user experience rate, the density of the number of connections, end-to-end delay, peak rate and mobility will be 5 g key performance indicators (kpis)., however, is different with the past only emphasize the peak rate, rate of the industry generally believe that the user experience is the most important performance index of 5 g, it truly reflects the users can obtain the true data rate, but also the most closely with the user feel performance metrics.Based on the technical requirement of 5 g scene mainly rate should achieve Gbps magnitude 5 g the user experience.In the face of diverse scenarios extreme differentiation performance requirements, 5 g hard as usual on the basis of a single technology form solutions for all scenarios.In addition, the current wireless technology innovation also presents the diversified development trend, in addition to the new multiple access technology, large-scale antenna array, the beam informs technology, super dense network, full spectrum access, a new network architecture is also thought to be main technical direction, 5 g all can in 5 g major technology play a key role in the scene.
Multi-input multi-output (MIMO) technology and the new multiple access technology combined with mass is one of the fundamental technology of the future 5 g system, due to the interference between users, the influence of channel noise, in order to satisfy the user's QOS requirements, in large-scale MIMO base station transmitting terminal and beam with vehicle technology, can greatly improve the signal-to-noise ratio at the receiving end.
Link adaptive is a effective way to improve communication performance and system utilization, by automatically adjusting the parameters of the transmitter to overcome the change of the channel environment, and obtain the optimal communication effect.The main characteristics of wireless channel is its link and link time-varying characteristic of open, and the increase of mobile users and the users of different service demand also increases the environmental complexity and randomicity.So by feedback, dynamic modulation transmitter beam forming matrix parameters, can get further improve performance of the system.

KEYWORDS: 5G ;massive mimo ;Link adaptaion.,beamforming.

目录

第五代移动通信系统链路自适应技术研究

摘 要 I

Abstract

II

第1章 绪论 6

1.1 研究背景与意义 6

1.2 5G技术的背景与研究现状 7

1.3 课题研究现状 8

1.4 论文主要工作与结构 10

第2章 理论分析：大规模MIMO的系统结构及性能以及链路自适应技术（波束赋形）

2.1 无线信道的特性 12

2.2 大规模MIMO系统综述 12

2.3 大规模MIMO系统模型，信道容量及功率分配 13

2.3.1 MIMO 系统模型

2.3.2 信道容量和注水原理

2.4 MIMO 信道空时编码技术 16

2.5 MIMO系统中的链路自适应技术 17

2.6 波束赋形技术介绍 19

2.6.1 波束赋形技术的理论基础

2.6.2几种已有的基本波束赋形种类

第3章 仿真验证及对波束赋形技术的改良 24

3.1 Matlab仿真验证

3.2 改良的波束赋形矩阵及性能验证

第4章 总结及展望 27

4.1 本文总结

4.2 对未来大规模MIMO技术的展望

参考文献 28。

致谢 29。

绪论

研究背景与意义

在过去的几十年时间里，移动通信系统的发展是爆炸式的，移动通信系统的发展目前已经经历了4代技术的变革，从1G,2G，再到3G以及到已得到广泛被采用的第四代移动通信系统，它们经历了迅速的发展，提高了人们的生活质量，每一次移动通信系统的技术升级，都意味着通信水平又达到了一个新的档次。4G LTE技术是为满足更高级移动通信的需求而建立的。在4G系统中，关键技术包括OFDM，新型的调制与编码，全IP技术等。4G网络中，以我们所用的手机为例的移动终端，可以达到100MB每秒左右的速率。4G网络现在发展很快，在世界范围内已经得到了较好的商用。近年来，移动通信产业已经成为当今社会中不可或缺的一部分，并且随着人们生活水平的提高，对更有质量的信息服务的需求也是日益见长。人们对通信的需求不再局限于电话，而是在信息的需求量以及更方便的通信方式度上呈现爆炸式增进，于是已有的技术也产生了一些短板，如流量的限制，频谱资源利用率不高等问题也得以凸显。由此产生了对第五代移动通信技术的研究，5G技术理论上可以满足未来十年网络流量增加一千倍的需求。5G技术需满足以下条件：

1. 满足大量的，高增长速率用户群体；
2. 更高的频谱利用率，更高的通信传输速率；
3. 更低的功耗。
4. 更高的灵活性，以应对信息社会的快速变化。

对5G的研究目前尚处于初级的探索阶段，要想让其真正得以运用，还需要面对许多技术上以及经营上的挑战。但是5G市场的发展也是朝气蓬勃的，它促成了新终端的产生，新的网路结构的部署以及更多的应用场景。因此需要我们不断开展研究，了解5G网络的最终需要及其核心技术体系以及发展前景为 5G 技术发展和普及寻找道路。

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