计算机与现代化

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一种基于邻接节点信息的合作式Ad Hoc网络协议

  

  1. 厦门大学信息科学与技术学院,福建厦门361005
  • 收稿日期:2014-02-12 出版日期:2014-03-24 发布日期:2014-03-31
  • 作者简介:袁鹏飞(1989-),男,江西乐平人,厦门大学信息科学与技术学院硕士研究生,研究方向:计算机网络技术; 井正伟(1987-),男,河南信阳人,硕士,研究方向:计算机网络技术。

A Cooperative MAC Protocol Based on Neighbor Nodes Information for Ad Hoc Networks

  1. School of Information Science and Technology, Xiamen University, Xiamen 361005, China
  • Received:2014-02-12 Online:2014-03-24 Published:2014-03-31

摘要: 在802.11协议中,DCF(Distributed Coordination Function)机制是节点共享无线信道进行数据传输的基本接入方式,为了解决无线网络中隐藏节点问题,使用RTS/CTS机制减少冲突,然而当网络节点数增加时,节点传输的冲突次数亦增加,从而使网络性能明显下降。因此,需要设计新的MAC协议,以适应当前Ad Hoc网络应用的快速发展。在IEEE 802.11的分布式协调功能访问机制(DCF)基础上,本文设计新的节点合作式的网络协议(C-MAC)。C-MAC节点通过控制帧获得本节点2跳内的邻接节点信息,并且根据邻接节点的信息设计调度算法,使节点以轮询的合作方式传输数据,有效地避免冲突。仿真实验表明,在改变节点速率、帧长度、网络节点数等参数情况下,分别以吞吐量、单帧传输时间和公平性为指标,对DCF和CMAC协议进行性能比较。在节点传输速率为11Mbps时,CMAC协议吞吐量比标准DCF最多可增加50%。

关键词: DCF, 合作式MAC协议, Ad Hoc网络, 吞吐量, 邻接节点列表

Abstract: DCF (Distributed Coordination Function) is a compulsory medium access control (MAC) scheme in IEEE 802.11 protocol. In order to avoid the performance degradation due to hidden nodes, DCF adopts RTS/CTS mechanism to decrease collisions. However, hidden node problem degrades system performance sharply when the number of wireless nodes increases. Therefore, it is necessary to design a novel MAC protocol to satisfy the requirements of Ad Hoc networks. Based on the Distributed Coordination Function (DCF) of IEEE 802.11, we design a cooperative MAC protocol (C-MAC). C-MAC node achieves the information of two-hop neighbor nodes from control frames, and according to the information of two-hop neighbor nodes, we design a scheduling algorithm to schedule each node to transmit at a particular time slot. We build a simulator to evaluate the performance of CMAC in terms of throughput, transmission time per hop and fairness index. When the transmission rate is 11Mbps, the throughput of CMAC increases 50% at most compared with the one of DCF.

Key words: DCF, cooperative MAC Protocol, Ad Hoc network, throughput, neighbor node list

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