计算机工程 ›› 2010, Vol. 36 ›› Issue (18): 285-287.doi: 10.3969/j.issn.1000-3428.2010.18.099

• 开发研究与设计技术 • 上一篇    下一篇

基于时隙选择概率分布的DCF区分服务机制

徐 颖1,白光伟1,王明超1,曹 磊1,2   

  1. (1. 南京工业大学计算机科学与技术系,南京 210009;2. 南京大学软件新技术国家重点实验室,南京 210093)
  • 出版日期:2010-09-20 发布日期:2010-09-30
  • 作者简介:徐 颖(1985-),女,硕士研究生,主研方向:区分服务,DCF性能分析与评价;白光伟,教授、博士;王明超,硕士研究生;曹 磊,博士研究生
  • 基金项目:

    国家自然科学基金资助项目(60673185);教育部留学回国人员科研启动基金资助项目(教外司留[2007]1108号);2006年度江苏省“青蓝工程”中青年学术带头人培养对象基金资助项目(苏教师[2007]2号)

Differentiated Services Mechanism Based on PDoSS in DCF

XU Ying1, BAI Guang-wei1, WANG Ming-chao1, CAO Lei1,2   

  1. (1. Dept. of Computer Science and Technology, Nanjing University of Technology, Nanjing 210009, China; 2. State Key Laboratory for Novel Software Technology, Nanjing University, Nanjing 210093, China)
  • Online:2010-09-20 Published:2010-09-30

摘要:

针对IEEE 802.11 DCF不能为实时业务提供服务质量保证的问题,提出一种简单的基于优先级的退避机制,根据不同等级数据业务的QoS需求提供区分服务。高优先级数据流采用减少数据包重传次数策略,低优先级数据流采用改进的RWBO+BEB退避机制,使得时隙选择概率分布均匀,能减少数据包碰撞概率。采用马尔科夫链模型对该机制进行数学分析与评价,结果表明,该机制不仅能够有效支持区分服务,并且能够提高系统饱和吞吐量。

关键词: 分布式协调功能, 服务质量, 时隙选择概率分布, 马尔科夫链模型

Abstract:

Considering that 802.11 DCF does not support any Quality of Service(QoS) for real-time traffic, this paper proposes a novel and simple priority-based backoff scheme to provide service differentiation according to different QoS requirements from different classes of traffic. For high-priority data flow, a strategy of reducing retransmissions is adopted. For low-priority data flow, an improved RWBO+BEB backoff algorithm is introduced to make the Probability Distribution of Slot Selection(PDoSS) even, and thus to reduce the packet collision probability. A Markov chain model is deployed and used to analyze and evaluate the mechanism performance. The mathematical analyses demonstrate that the proposed mechanism can support QoS in 802.11 DCF effectively, moreover, improve the overall system performance significantly.

Key words: Distributed Coordination Function(DCF), Quality of Service(QoS), Probability Distribution of Slot Selection(PDoSS), Markov chain model

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