Performance Analysis of a Handover Mechanism for a Mobile Wireless Sensor Network

Several applications have been proposed for mobile wireless sensor networks. Some of these applications require the transfer of a large amount of data in a short period of time. This is challenging, since the mobile node may be required to repeatedly establish a link with multiple relay nodes which proceed to forward the data to the base station. Apart from the technical difficulty mobility may cause, there is an associated latency to the data transfer. One way to deal with the problem of latency is to timely foresee the deterioration in the quality of a link and to seamlessly transfer the communication to a more stable link. This paper extends the RI-MAC protocol to support a seamless handover. Once a mobile node realizes that its data packets cannot be completely transmitted before an existing link breaks, it will search for a new relay node without interrupting the communication with the current node. The paper sets up a mathematical model to investigate the latency associated with a handover. The analytic model quantifies the handover latency as a function of the network density and the duty cycle.