LTE-A中继蜂窝系统调度算法研究及性能评估

发布时间：2018-02-15 21:42

本文关键词： LTE-A 中继蜂窝系统系统级仿真资源调度算法　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：LTE-A系统在数据速率、频谱效率、时延等方面具有比LTE系统更高的需求。为了达到LTE-A的性能要求,3GPP提出了多用户MIMO、多点协同、载波聚合和中继等增强型技术。其中,中继技术可以扩大网络覆盖、有效消除盲区、提高系统吞吐量,以及降低网络建设成本,已成为LTE-A系统中的研究热点。而中继的引入增加了新的数据链路,增大了系统的资源消耗,使系统中的资源调度和分配问题变得更加复杂,因此在中继增强的蜂窝系统中进行合理的资源调度以提高系统性能,具有重要的研究意义。本文首先详细介绍了中继技术并对中继蜂窝系统进行了概述,之后结合3GPP相关协议和提案,搭建了LTE-A TDD下行中继系统级仿真平台,为后文的调度算法研究奠定了基础,并重点阐述了各中继增强模块的设计,包括小区拓扑模型、无线信道建模、天线模型、用户生成和接入选择、接收上行反馈、资源调度模块、链路质量模块以及链路性能模块。其次,研究了传统蜂窝系统的三种经典调度算法:轮询调度RR、最大载干比调度MAX C/I和比例公平调度PF,并在建立的中继系统仿真平台上实现了这三种算法,仿真结果显示PF算法能获得吞吐量和公平性的折中,达到相对较好的性能。然后,重点研究了中继蜂窝系统的资源调度算法,分析了中继蜂窝系统中常用的自适应分布式比例公平ADPF调度算法,ADPF不能有效地保证backhaul和access链路吞吐量的平衡,公平性较差。随后本文提出了一种基于中继缓存的两跳平衡分布式调度算法TBDRC。在第一跳调度时,基站根据中继的缓存信息自适应调整平衡backhaul和direct链路占用的资源块数目,以达到提高资源利用率、资源块公平性和传输吞吐量的目的。在第二跳调度时,中继根据各中继用户的传输块大小计算应该给各中继用户分配的资源块数目,避免了资源浪费,可以减少access和direct链路之间的干扰,提高用户公平性。并在建立的中继系统仿真平台上实现了ADPF和TBDRC算法。通过与PF和ADPF算法进行仿真比较,验证了TBDRC能通过平衡backhaul和access链路的吞吐量,大幅提高资源利用率和用户公平性,并在一定程度上提高了系统吞吐量,能获得系统吞吐量和用户公平性的折中。最后,基于中继系统仿真平台和本文所提的TBDRC算法,从多方面评估了不同中继数目对系统性能的影响。
[Abstract]:LTE-A system has higher demand than LTE system in data rate, spectrum efficiency, delay and so on. In order to meet the performance requirement of LTE-A, 3GPP has proposed multi-user Mimo, multi-point cooperation, carrier aggregation and relay, etc. Relay technology can expand network coverage, effectively eliminate blind areas, improve system throughput, and reduce network construction costs, which has become a research hotspot in LTE-A systems, and the introduction of relay has added new data links. It increases the resource consumption of the system and makes the problem of resource scheduling and allocation in the system more complicated. Therefore, reasonable resource scheduling is carried out in the relaying enhanced cellular system to improve the performance of the system. This paper introduces the relay technology in detail and gives an overview of the relay cellular system. Then the simulation platform of LTE-A TDD downlink relay system is built based on 3GPP protocols and proposals. It lays a foundation for the research of scheduling algorithm in the future, and focuses on the design of each relay enhancement module, including cell topology model, wireless channel modeling, antenna model, user generation and access selection, and receiving uplink feedback. Resource scheduling module, link quality module and link performance module. Secondly, In this paper, three classical scheduling algorithms for traditional cellular systems: polling scheduling, maximum load to interference ratio scheduling MAX C / I and proportional fair scheduling are studied, and these three algorithms are implemented on the established relay system simulation platform. Simulation results show that the PF algorithm can achieve a tradeoff between throughput and fairness, and achieve relatively good performance. This paper analyzes that the adaptive distributed proportional fair ADPF scheduling algorithm commonly used in relay cellular systems can not effectively guarantee the balance of backhaul and access link throughput. The fairness is poor. Then we propose a two-hop balanced distributed scheduling algorithm based on relay cache. In the first hop scheduling, the base station adaptively adjusts the number of resource blocks occupied by the balanced backhaul and direct links according to the buffer information of the relay. In order to improve resource utilization, resource block fairness and transmission throughput, in the second hop scheduling, relay calculates the number of resource blocks to be allocated to each relay user according to the size of each relay user, thus avoiding the waste of resources. It can reduce the interference between access and direct links and improve the user fairness. ADPF and TBDRC algorithms are implemented on the established relay system simulation platform. The simulation results are compared with PF and ADPF algorithms. It is verified that TBDRC can improve resource utilization and user fairness by balancing the throughput of backhaul and access links, improve system throughput to a certain extent, and achieve a compromise between system throughput and user fairness. Based on the relay system simulation platform and the TBDRC algorithm proposed in this paper, the effects of different relay numbers on the system performance are evaluated from many aspects.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5

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