【作者】 陈东；

【导师】 张冰；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2008， 硕士

【摘要】 WiMAX标准定义了无线城域网的MAC层和物理层技术规范。在MAC层,标准将不同的业务流归类为UGS,rtPS,nrtPS和BE四种类型,分别对四种业务流进行QoS保证。在物理层,采用OFDM等技术为数据在复杂的物理环境中传输提供可靠的保证。虽然标准为不同业务提供了QoS保障机制,但是标准并没有给出保证这些QoS需求所要使用的资源调度算法。因此,这些问题成为人们对WiMAX技术进行深入研究的热点。本文主要研究了基于WiMAX的QoS保障机制的资源调度算法设计与实现。首先对WiMAX标准的内容做了简单的介绍,接着对WiMAX的带宽管理机制和现有的各种分组调度算法做了综述。在此基础上提出了DRR算法在WiMAX系统中的改进算法(I-DRR)。利用搭建的WiMAX仿真平台对改进的DRR算法性能进行了仿真研究。仿真结果表明,I-DRR算法在吞吐量、时延、带宽利用率方面确实比DRR算法有了很大的提高。通过与PQ算法相比较发现,I-DRR算法具有更好的公平性。更多还原

【Abstract】 The MAC layer and PHY layer specifications are defined in WiMAX standard. Service flows are classified into the UGS, rtPS, nrtPS and BE types according to their QoS requirements, and the QoS requirements are satisfied by the MAC layer mechanisms respectively. In PHY layer, OFDM technique is introduced to guarantee the reliable data transmission in complicated physical environments. Although perfect QoS guarantee are provided for different services, the packet scheduling algorithms to implement the QoS support are not given by the standard. All these issues are left for people to reaserch.The design and implementation of packet scheduling algorithms based on WiMAX’s QoS guarantee are discussed in this thesis.In this paper, WiMAX standard is described firstly. Then we give an introduction to the basic knowledge and research on bandwidth management mechanism and existing packet scheduling algorithms. Based on these, the I-DRR(Improved-DRR) algorithm which is improved from Deficit Round Robin algorithm is given and is simulated on simulation tool we have implemented for WiMAX. The simulation results show that compared with DRR, the I-DRR has better performaces on throughput, delay and bandwidth usage ratio and shows better fairness than Priority Queue algorithm.更多还原