Iwata Masanari, Tang Suhua, Obana Sadao
Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan.
Sensors (Basel). 2018 Apr 6;18(4):1121. doi: 10.3390/s18041121.
In large-scale wireless sensor networks (WSNs), nodes close to sink nodes consume energy more quickly than other nodes due to packet forwarding. A mobile sink is a good solution to this issue, although it causes two new problems to nodes: (i) overhead of updating routing information; and (ii) increased operating time due to aperiodic query. To solve these problems, this paper proposes an energy-efficient data collection method, Sink-based Centralized transmission Scheduling (SC-Sched), by integrating asymmetric communication and wake-up radio. Specifically, each node is equipped with a low-power wake-up receiver. The sink node determines transmission scheduling, and transmits a wake-up message using a large transmission power, directly activating a pair of nodes simultaneously which will communicate with a normal transmission power. This paper further investigates how to deal with frame loss caused by fading and how to mitigate the impact of the wake-up latency of communication modules. Simulation evaluations confirm that using multiple channels effectively reduces data collection time and SC-Sched works well with a mobile sink. Compared with the conventional duty-cycling method, SC-Sched greatly reduces total energy consumption and improves the network lifetime by 7.47 times in a WSN with 4 data collection points and 300 sensor nodes.
在大规模无线传感器网络（WSN）中，靠近汇聚节点的节点由于数据包转发而比其他节点更快地消耗能量。移动汇聚节点是解决此问题的一个好方法，尽管它给节点带来了两个新问题：（i）更新路由信息的开销；以及（ii）由于非周期性查询导致运行时间增加。为了解决这些问题，本文提出了一种基于汇聚节点的集中式传输调度（SC-Sched）的节能数据收集方法，通过集成非对称通信和唤醒无线电。具体来说，每个节点都配备了一个低功耗唤醒接收器。汇聚节点确定传输调度，并使用大发射功率发送唤醒消息，直接同时激活一对将以正常发射功率进行通信的节点。本文进一步研究了如何处理由衰落引起的帧丢失以及如何减轻通信模块唤醒延迟的影响。仿真评估证实，使用多个信道有效地减少了数据收集时间，并且SC-Sched在移动汇聚节点的情况下工作良好。与传统的占空比方法相比，在具有4个数据收集点和300个传感器节点的WSN中，SC-Sched大大降低了总能耗，并将网络寿命提高了7.47倍。
