A Mobility Management Protocol for Wireless Sensor Networks

Wireless sensor networks supporting the free mobility of nodes can be useful for several applications. For example, in residential areas and rehab centres, sensors can be attached to subjects to monitor their movements, body exertions, and cardiac activities. These benefits, however, are also challenged by the difficulty of establishing reliable and stable links. In cellular networks, mobile stations are always associated with the nearest base station through intra- and inter-cellular handover. The underlying process is that the quality of an established link is continually evaluated and handover decisions are dully made by resource rich base stations. In wireless sensor networks, should a seamless handover be carried out, the task has to be accomplished by energy constraint, resource-limited, and low-power wireless sensor nodes in a distributed manner. In this paper we propose a sender-initiated mobility management protocol to enable seamless handover. We have fully implemented the protocol in TinyOS environment for the TelosB and Imote2 platforms, experiment results showing that our protocol achieves high reliability and triggers less handover requests (less than 50% to 80%) compared to three state-of-the-arts. Furthermore, our protocol reduces the signalling overhead by up to 95%.