| 摘要: |
| IEEE 802.11 网络中的传统退避算法利用竞争窗口机制进行冲突解析,冲突节点被重新分布在一个更大的窗口范围内以避免冲突.然而,只要这些分布窗口之间存在着交集,就仍有可能引发冲突.为了解决一个问题,提出了一种冲突分类模型,将网络中的分组冲突分成交叉冲突和同级冲突,并且提出针对这两种不同类型的冲突应该采取不同的策略进行解析.利用顺序离散窗口分布机制(sequential discrete window distribution,简称SDWD)解析交叉冲突,通过节点分布窗口的离散化避免交叉冲突;同时,通过 |
| 关键词: IEEE 802.11 分布协调函数 退避 冲突分类模型 顺序离散窗口分布 |
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| 基金项目:Supported by the National Natural Science Foundation of China under Grant Nos.60602029, 60772088 (国家自然科学基金); the Young and Middle-Aged Elitists’ Scientific and Technological Innovation Team Project of the Institutions of Higher Education in Hubei Province of China under Grant No.T200902 (湖北省高等学校优秀中青年科技创新团队资助计划项目); the Scientific Research Projects of Hubei Education Department of China under Grant Nos.D20081904, Q20091903, B20091904 (湖北省教育厅科研项目); the Young Scientific Research Project of Hubei University of Economics of China under Grant No.XJ2009011 (湖北经济学院校级青年项目) |
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| Collision Classification Model-Based Collision Resolution Algorithm |
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ZHANG Qi-Fei,LIU Wei,SUN Bao-Lin,GUI Chao,YAN Bing
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| Abstract: |
| Traditional backoff algorithms in IEEE 802.11 networks adopt contention window scheme for collision resolution. Collided nodes are redistributed in extended window ranges to avoid further collisions. However, as long as these distribution windows intersect with each other, collision may still occur. To solve this problem, this paper puts forward a collision classification model to classify collisions into cross collision and intra collision and proposes to solve them with different policies. It utilizes sequential discrete window distribution (SDWD) scheme to resolve cross collision by distributing the collided nodes in a series of discrete Elementary Windows and the intra collision is resolved with an appropriate elementary window size to achieve a tradeoff between intra collision probability and packet latency. Based on this proposal, two algorithms are developed featuring cross collision resolution (CCR) and collision-free CCR (CF-CCR). The extensive simulations demonstrate that compared with IEEE 802.11 DCF protocol, the CCR and CF-CCR algorithms consistently excel, in terms of collision rate,throughput, delay, fairness and delay jitter. Moreover, CCR and CF-CCR exhibit their respective advantages in different scenarios. |
| Key words: IEEE 802.11 DCF backoff collision classification model sequential discrete window distribution |
