Mobility Support in Wireless Sensor Networks
The focus is on the development of a novel, intelligent controller to support mobility in wireless sensor networks (WSNs). Particularly, the deployment of such mobility solution is in critical applications, like personnel safety in an industrial environment. A fuzzy logic-based mobility controller is proposed to aid sensor Mobile Nodes (MN) to decide whether they have to trigger the handoff procedure and perform the handoff to a new connection position or not. To do so, we use a combination of two locally available metrics, the RSSI and the Link Loss, in order to “predict" the End-to-End losses and support the handoff triggering procedure. As a performance evaluation environment, a real industrial setting (oil refinery) is used. Based on onsite experiments run in the oil refinery testbed area, the proposed mobility controller has shown significant benefits compared to other conventional solutions, in terms of packet loss, packet delivery delay, energy consumption, and ratio of successful handoff triggers. Further, we have evaluated the stability and boundedness of our system using phase plane analysis, with supportive results.
The uniqueness of this work is threefold. Firstly, an intelligent controller, based on fuzzy logic is proposed. Secondly, a real industrial setting (oil refinery) is used as the evaluation environment, something that poses new challenges regarding the design of mobility support. Thirdly, the approach taken has greater applicability to any WSN industrial environment or testbed setting with mobility requirements, due to the fact that it is designed based on network state parameters that are available to all sensor MNs. The selection of fuzzy logic system is based on its simplicity and the fact that since it processes experts-defined rules governing the target control system, it can be modified to improve system performance.