LTE下行链路分组调度算法研究和仿真.pdf

Research And Simulation On Packet SchedulingFor LTE Downlink ThesisSubmitted toNanjing University of Posts and munications for the Degree of Masterof EngineeringByChengping GuiSupervisor: Prof. Xuerong QianFebruary 2013I摘要LTE项目是3G技术的演进发展,最早于2004年3GPP的多伦多会议被提出,并得到广泛的关注,对LTE的研究已经成为通信领域研究的主流方向。由于无线资源的有限性,如何进一步提高无线资源的利用率和尽可能的增加系统容量,逐渐成为当今通信界的研究热点。性能良好的分组调度算法是解决这一问题的关键,本文正是以LTE系统下行链路为研究背景,对分组调度算法进行研究。论文在对移动通信系统和LTE的发展演进做简要介绍之后,首先对LTE系统的框架结构、主要接口及无线接口协议和关键技术进行了概括性描述,通过介绍对LTE系统获得一个整体了解和认识;然后对无线通信系统中的无线资源管理和分组调度算法展开了详细说明,并对四种经典的分组调度进行阐述和性能比较;最后针对LTE下行链路中的分组调度算法进行了深入的研究,并通过仿真进行验证。本文的研究重点在第四章和第五章,在对现有分组调度算法的研究的基础上,提出了一种针对实时性业务的性能良好的分组调度算法,该算法使用动态的优先级函数来确定系统中用户被调度的优先级顺序,该优先级函数以系统中用户的HOL数据包延迟、丢包率、用户的瞬时速率和QoS要求的延迟门限以及用户可以接受的最大丢包率为参数。如此设置使得在对系统中的用户进行调度时,既考虑到实时性业务服务类型对于延时比较敏感的特点,又将用户的不同的信道情况考虑在调度决策中,因而实现了在满足用户不同服务的QoS需求的前提下,尽可能增加系统吞吐量的目标。通过仿真结果,验证了提出算法的可行性和性能的改善。关键词:LTE,分组调度,服务质量,HOL数据包延迟IIAbstractLTE project is the evolution of 3Gtechnology. Researchon LTE has received widespread attention and has e the mainstreamdirectionof the communications industry. Due to the limited radio resources, research on how to improve the system throughputand spectral efficiency has ethe hot spot of today's communication sector. Good performance packet scheduling algorithm isthe keymethodto solve this problem. This paper is aim to researcha well-performedpacket scheduling algorithmapplied to the downlink LTE of the LTE systeminclude LTE frame structure, the main interface and wireless interface protocolsand main key technologies are propised in the beginning of the detailed description on the radio resource management in munication system andsome packet scheduling algorithmsare this thesis shows a detailed introductionon a newproposed packet scheduling algorithm and the simulationresults are given in Chapters IV and main point of this paperisin Chapters IV and V, a good performance packet scheduling alg