Xu Zhezhuang, Liu Guanglun, Yan Haotian, Cheng Bin, Lin Feilong
School of Electrical Engineering and Automation, Fuzhou University, Fuzhou 350116, China.
Department of Electronic and Information Engineering, Hong Kong Polytechnic University, Hong Kong 999077, China.
Sensors (Basel). 2017 Oct 27;17(11):2468. doi: 10.3390/s17112468.
In wireless sensor and actor networks, when an event is detected, the sensor node needs to transmit an event report to inform the actor. Since the actor moves in the network to execute missions, its location is always unavailable to the sensor nodes. A popular solution is the search strategy that can forward the data to a node without its location information. However, most existing works have not considered the mobility of the node, and thus generate significant energy consumption or transmission delay. In this paper, we propose the trail-based search (TS) strategy that takes advantage of actor's mobility to improve the search efficiency. The main idea of TS is that, when the actor moves in the network, it can leave its composed of continuous footprints. The search packet with the event report is transmitted in the network to search the actor or its footprints. Once an is discovered, the packet will be forwarded along the trail until it is received by the actor. Moreover, we derive the condition to guarantee the trail connectivity, and propose the redundancy reduction scheme based on TS (TS-R) to reduce nontrivial transmission redundancy that is generated by the trail. The theoretical and numerical analysis is provided to prove the efficiency of TS. Compared with the well-known expanding ring search (ERS), TS significantly reduces the energy consumption and search delay.
在无线传感器与执行器网络中，当检测到事件时，传感器节点需要发送事件报告以通知执行器。由于执行器在网络中移动以执行任务，传感器节点始终无法获取其位置。一种常见的解决方案是搜索策略，该策略可以将数据转发到没有其位置信息的节点。然而，大多数现有工作并未考虑节点的移动性，从而产生了大量的能量消耗或传输延迟。在本文中，我们提出了基于轨迹的搜索（TS）策略，该策略利用执行器的移动性来提高搜索效率。TS的主要思想是，当执行器在网络中移动时，它可以留下由连续足迹组成的轨迹。带有事件报告的搜索数据包在网络中传输以搜索执行器或其足迹。一旦发现轨迹，数据包将沿着轨迹转发，直到被执行器接收。此外，我们推导了保证轨迹连通性的条件，并提出了基于TS的冗余减少方案（TS-R）以减少由轨迹产生的不必要的传输冗余。提供了理论和数值分析以证明TS的效率。与著名的扩展环搜索（ERS）相比，TS显著降低了能量消耗和搜索延迟。
