ECCRA: An energy-efficient coverage and connectivity preserving routing algorithm under border effects in wireless sensor networks

Wireless sensor networks can be used to monitor the interested region using multi-hop communication. Coverage is a primary metric to evaluate the monitoring capacity. Connectivity also should be guaranteed so that the sink node can receive all sensed data for future processing. In this paper, combining these two problems, we study the connected, coverage problem given a specific network coverage ratio under border effects. We consider the scenario where the sensor nodes are distributed in a circle-shaped region uniformly. We first derive the network coverage provided by N sensor nodes by the mathematical formulae exactly. The lower bound of the network connectivity probability is also derived. Since sensor nodes are equipped with energy-limited batteries, energy conservation in such networks is of paramount importance to prolong the network lifetime. Accordingly, we then propose a location-independent, energy-efficient routing algorithm ECCRA which achieves the required network coverage and sensor connectivity simultaneously. The extensive simulation results demonstrate that our algorithm is correct and effective. (C) 2008 Elsevier B.V. All rights reserved.