一种IEEE 802.11接入机制的新退避算法

无线传感器网络采用类似开放式系统互联模型的协议栈,作为第一个完全针对无线传感网络设计的MAC协议,S-MAC采用了IEEE802.11DCF的接入机制。本文在分析了IEEE802.11协议的二进制指数退避算法(BEB),以及倍数增线性减退避算法(MILD)后,提出了一种基于网络性能指标的新退避算法。新算法将无线信道中的时隙利用率映射网络性能指标传输概率,对网络中连续两次发送的时隙利用率进行平均滤波处理,改变重传节点的发送优先级,来调整节点在竞争使用窗口的退避值,以达到有效减少网络的碰撞、提高无线信道的使用效率和网络吞吐率的目的。仿真结果表明,新退避算法能更准确地估计网络当前的竞争状态,有效地提高了网络吞吐率,获得较好的网络性能。

A New Backoff Algorithm Based on the IEEE 802.11 Access Mechanism

Wireless Sensor Networks used a similar open systems interconnection model of the protocol stack,as the first MAC protocol completely designed for Wireless Sensor Networks,S-MAC used the IEEE 802.11 DCF access mechanism.After the analysis of Binary Exponential in the IEEE 802.11 protocol and Multiplicative Increase Linear Decrease Backoff Algorithm,a new backoff algorithm based on the network performance was proposed.The new algorithm reflected slot utilization to transmission probability in the wireless channel,making a average filter of every twice sending slot and changing sending priority of the re-node in the network to modulate the backoff collision window of the node,which reduced the network collision effectively and improved the use of wireless channel and network throughput efficiency.The simulation results show that,the new backoff algorithm can estimate the current network competition more accurately,increase the network throughput effectively,and make a better network performance.