摘要
伴随着移动终端和移动应用业务的不断发展,我们正逐渐迈入移动互联网时代。如何满足移动用户对高速率,低干扰等通信环境的要求,已经成为下一代无线通信网络所面临的重要课题。为此,第三代合作伙伴组织(3GPP)在LTE网络架构基础上引进了多点协作传输(CoMP)等关键技术。CoMP技术通过处于不同地理位置的多个传输点之间的协作为用户提供数据服务,降低了传输点之间的干扰,提高了小区吞吐量尤其是小区边缘吞吐量。该技术已经成为近年来LTE-Advanced的研究热点之一。
CoMP技术的实现方式主要分为联合处理(JP)和协作调度/协作波束赋形技术(CS/CB)两种。其中CoMP-JP技术通过多个发送点联合为用户传输数据信息,实现干扰消除与系统吞吐能力的提升。COMP-CS/CB技术通过独立传输点为用户传输数据,但对用户的调度和波束赋形通过多个传输点之间协作决定。相对于CoMP-JP技术而言,COMP-CS/CB系统易于实现,同时也可以有效地避免干扰,达到较好的系统性能。
本论文主要针对COMP技术中的COMP-CS/CB技术进行研究,以该技术方案为基础,利用系统仿真,对CoMP-CS/CB技术的两种实现方案进行了研究,并对这两种实现方案进行了改进及验证。本文主要做了以下工作：
(1)根据3GPP仿真要求,按照3GPPTR36.819中的仿真场景,搭建了CoMP-CS/CB的系统级仿真平台。并进行了COMP-CS/CB技术的实现与评估。
(2)针对显式信道信息反馈集中式CS/CB调度过程中调度复杂度较高的问题,提出了区分首用户的CS/CB调度算法及调度器实现,并对算法进行了评估和分析。
(3)针对隐式信道信息反馈分布式CS/CB调度过程中上行信道反馈量较高的问题,提出了基于信干噪比和最佳预编码指示配对进行反馈用户选择的分布式最差合作伙伴实现方式,并对算法进行了评估与分析。
Along with the continuous development of the mobile terminals and mobile applications, we are moving into the era of mobile Internet. How to meet the requirements of the mobile users for high-speed, low interference communication environment has become an important issue facing the next generation of wireless communication network. For that The3rd Generation Partnership Project (3GPP) has introduced several key technologies such as Coordinated Multi-Point transmission/reception (CoMP). CoMP shall reduce the inter-cell interference and improve the system throughput especially the cell edge user throughput by the cooperation of several different transfer points Located in different geographic positions. This technology has become one of the hot spots of LTE-Advanced Research in recent years.
As a general view two main families of coordination methods have emerged for CoMP, Joint Processing (JP) and Coordinated scheduling and beamforming(CS/CB). JP means a coordination in which multiple entities are simultaneously transmitting/receiving to/from UEs located in the coordination area. CS/CB means coordination where each UE is communicating with a single transmission/reception point, but the transmission/reception is made with an exchange of control information among the coordinated entities. Compared with CoMP-JP, the CS/CB system is easier to implement, and also can effectively avoid interference to achieve a good system performance.
This thesis mainly study the Coordinated scheduling and beamforming(CS/CB) technique of CoMP. Based on this technique we focus on two main implementations'simulations and improvements. The contributions of this paper as follow:
First, CoMP-CS/CB system simulation platform has been built according to the requirement of3GPP standard and the simulation scenario of Technique Specification36.819. The evaluation includes the centralized and distributed CoMP-CS/CB system.
Second, according to the high degree of complexity of the explicit feedback centralized CS/CB scheduling process, this thesis proposes a CS/CB scheduling algorithms with distinguishing the first user. And the validity of the algorithm is evaluated by several results and analysis.
Third, focusing on the problem of high amount of the uplink feedback of the implicit feedback distributed CS/CB scheduling proposes, the author proposes a distributed Worst Companion Instruction (WCI) scheme based on the feedback users selection. And the validity of the algorithm is evaluated by several results and analysis.
引文
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