基于ieee 802.16的mac层qos技术研究based on the ieee 802.16 mac layer qos technology research.docx

Classified index: :
Dissertation for the Master’s Degree in Engineering
RESEARCH ON MAC LAYER QOS TECHNOLOGY BASED ON IEEE
Candidate: Zhao Jinkui
Supervisor: Prof. Gu Xuemai
Academic Degree Applied for: Master of Engineering
Specialty: Information munication
Engineering
School of
Electronics
and
Information
June, 2009
Engineering
Affiliation:
Date of Denfence:
Degree-conferring-Institution: Harbin Institute of Technology
摘 要
随着无线通信技术的发展,人们对 VoIP 电话、视频会议等多媒体业务的需求不断增加,与网页浏览、FTP 服务、E-mail 等传统业务相比它们对网络性能提出了不同的要求。不同类型的业务具有各自明确的服务质量成为现代网络通信的一大特征。而由于无线资源的缺乏、无线信道的不可靠性和时变特性, 如何针对不同类型业务的特点提供相应可靠的 QoS 保证成为当前无线网络中研究的热点问题。
IEEE 宽带无线接入技术作为有竞争力的下一代无线网络技术,已经把为多种业务提供 QoS 支持的问题提上了日程。IEEE 的 MAC 层协议对服务流、业务类型、带宽请求与分配机制以及 QoS 架构和相应的信令交互机制等进行了详细的定义,却把接纳控制、分组调度等一系列重要问题留待开发者来解决。
本文主要针对 IEEE 中未定义的接纳控制和分组调度部分展开研究。在对 IEEE 的 MAC 层 QoS 机制系统理解的基础上,对已有的接纳控制算法和分组调度算法进行了深入的分析和研究。对于接纳控制部分,本文设计了一种基于门限的抢占式接纳控制算法,该算法为不同类型的业务设置相应的“软”门限或“硬”门限,在保证了系统带宽利用率的同时提高了不同业务的公平性;对于分组调度部分,本文提出了一种改进的分层带宽调度架构, 基于该架构提出了一种改进的调度算法 I-DFPQ 并利用 C++实现。实测结果表明,本文提出的 I-DFPQ 算法能够很好的适应无线链路的可变性,在系统吞吐量、带宽利用率、时延和公平性等方面都有很好的表现。
关键词:IEEE ;QoS;接纳控制;分组调度
Abstract
With the development of munication, people have more and more demands on VOIP telephone, video conference and other multimedia services, compare with the traditional web browser, FTP service and E-mail, they put forward different requirements work performance. Different services have their own specific quality of service has e a major character of munication. Because of the limited wireless resources, the unreliable and time-varying characteristics of wireless channels, how to provide reliable QoS for different services es a hot issue in work.
As petitive next-generation work technology, IEEE broadband wireless access technology has put it on the agenda that provide QoS support for multiple services. IEEE standard specifies QoS mechanisms such as service flow, service types, bandw