基于数据优先级的IEEE 802.15.4自适应占空比方案

AN ADAPTIVE DUTY CYCLE SCHEME IN IEEE 802.15.4 BASED ON DATA PRIORITY

IEEE 802.15.4 MAC标准采用可选的活跃/休眠交替的超帧结构来节省网络的能耗,从而大大延长了网络生命周期。无线传感器网络节点的业务流量是时刻变化的,数据信息也存在不同优先级。而IEEE 802.15.4采用统一CSMA/CA方式访问信道没有考虑数据优先级,另外活跃期和休眠期的固定占空比在动态适应性方面表现不佳。由此,提出一种节点根据业务流量不同,区分数据优先级的自适应的改变节点占空比的方案。仿真结果表明,该方案能够动态自适应网络业务流量的变化,降低了网络功耗并且提高了网络吞吐量。

The IEEE 802.15.4 standard adopts optional superframe structure which alternates the activity and dormancy to save network energy so that the network lifetime is extended greatly.The traffic load is varying from time to time in WSN, and the data information has different priority as well.But IEEE 802.15.4 adopts uniform CSMA/CA pattern to access the channel without considering the data priority. Besides, the fixed duty cycle performs poorly in both active and dormant period in terms of dynamic adaptability.Therefore, we propose an adaptive scheme to alter duty cycle of nodes, in it the node will differentiate the data priority according to different traffic load.Simulation results show that the scheme can dynamically adapt to the changes in network traffic load, reduces network energy consumption and improves network throughput.