On Configuring Directional Transmission for Path Exposure Reliability in Energy Harvesting Wireless Sensor Networks

In this paper, we consider a path exposure problem in energy harvesting wireless sensor networks (EH-WSNs) where nodes are equipped with directional communication devices. Nodes harvest energy from ambient environment (e.g., solar power), and manage fluctuations in their stored energy by adjusting some of their directional transmission parameters. Using a probabilistic graph model we formalize a problem, denoted DirEXPO-RU, that quantifies the ability of a network to detect and report traversal along a given path as probability representing the reliability of the network in performing the path monitoring task. A problem that arises in managing the network resources to maximize this reliability measure is to adjust the transmission beam width of each node, given that nodes beam centers are given as input. We develop a heuristic algorithm to deal with the problem, and use the algorithm in a framework for computing lower bounds on the reliability of the overall network. The obtained numerical results show improvement in the achieved network reliability.