一种超低功耗无线传感器网络MAC协议

An Ultra-Low Power MAC Protocol for Wireless Sensor Networks

在无线传感器网络中,能量是一个关键资源。传感器网络节点通常在大部分时间里处于休眠状态以节约能量。其中,节点间精确地同步和超低的休眠功耗能够本质上延长无线传感器网络节点的寿命。然而现实中节点在唤醒周期设置、时钟源选择和网络节点同步时很难满足理论研究时提出的要求。因此,提出了一种低功耗无线传感器网络MAC协议:允许节点使用多种时钟源实现功耗最优配置,在休眠时采用内部时钟以达到最低功耗,在工作时采用外部晶振以保证射频性能,同时为了解决多时钟源误差增大且休眠周期变化带来的问题,提出了多时钟源休眠唤醒机制和节点同步策略。最后文章在IEEE802.15.4硬件测试平台上完成了多时钟源MAC协议与SMAC协议的实证测试,结果表明对比SMAC协议的唤醒和同步机制,低功耗无线传感器网络MAC协议在传感器网络节点上能够极大地减少休眠功耗并显著地节约同步的时间,从而大大延长节点寿命。

Energy is a critical resource in wireless sensor networks. In order to save the power,sensor nodes need to sleep most of time. Therefore,precise synchronization between nodes and ultra-low sleeping energy consumption is essential for prolonging network lifetime. However,when considering the configuration of wake-up time,clock source selection and the nodes synchronization problem in the actual use of the environment. There are some problems diffi-cult to meet the requirements of the theory research. A new ultra-low power WSN MAC protocol（ ULP-MAC） is pro-posed：Allow the sensor nodes to use serval kinds of clock to realize the optimal configuration of power consumption, using internal clock for the lowest power comsumption and switching to outside clock for the RF transceiver. At the same time,in order to slove the problem about the clock error increasing and the change of sleep cycle,this paper proposes the multi-clock wake-up mechanism and the nodes synchronization strategy. Finally this paper evaluates the introduced protocol and the SMAC protocol in a realistic IEEE802.15.4 test bed. The results show that,com-pared to SMAC mechanism,the ULP-MAC,which significantly decrease the sleep power comsumption and the syn-chronization time,greatly extend the life of the nodes.