Timing and Radius Considerations for Maintaining Connectivity QoS

Given the potential scale on which a Wireless Sensor Network (WSN) can be deployed, multi-hop communication will be a pivotal component of the system. When redundant nodes are deployed, which are hibernated opportunistically to conserve energy, it is crucial that sub-graphs of the network are not disconnected by the hibernation of a node. In order to ensure connectivity is preserved for all nodes in the area, a protocol is required that oversees routing integrity is maintained. Since this routing topology must be present at all times, this set represents the minimum number of nodes that must be active at any given time for a functioning network. In this paper, the performance of such a protocol is evaluated, in terms of message delivery and node lifetime for various timing and radius parameters. The selection of these, control the potential energy conserved by the nodes through the hibernation process, which can increase operational longevity. In addition, the radius governs the networks resilience to expired nodes, while timing parameters manage the responsiveness of the topology to failed and exhausted sensors. In this paper, we demonstrate the trade-offs that exist when selecting specific values for these variables as well as the impact these have on a number of Quality of Service (QoS) metrics for WSN performance, namely longevity and message delivery.