Efficiency Impairment of Sensor Area Coverage Protocols under Realistic Physical Layer Conditions

Most of existing works about sensor networks focus on energy management. Already proposed solutions often consist in balancing energy consumption by taking advantage of the redundancy induced by the random deployment of nodes; some nodes are active while others are in sleep mode, thus consuming less energy. Such a dynamical topology should not impact the monitoring activity. Area coverage protocols aim at turning off redundant sensor nodes in order to constitute a set of active nodes that covers as large an area as the whole set of nodes. In this paper, we focus on localized algorithms that require 1-hop knowledge only to allow nodes to choose their activity status. The unit disk model is the most commonly used assumption; if a node emits a message, any node within its communication range receives it while any node outside the disk does not. In this article, the impact of a realistic radio channel on area coverage protocols for wireless sensor networks is studied. It is shown that a non-binary reception probability can lead to very different results for protocols that could though provide great performances with the unit disk model. An optimization of a protocol to keep increasing the network lifetime once a realistic energy consumption model is considered is also provided