Coverage Optimizing and Node Scheduling in Directional Wireless Sensor Networks

Most of previous works on coverage problem are based on omni-directional sensing model. Due to different sensing capability in different direction, directional sensor networks require new solutions. We present two direction optimizing algorithms: greedy direction adjusting (GDA) algorithm and equitable direction optimizing (EDO) algorithm. GDA algorithm optimizes direction merely according to the amount of covered targets. EDO algorithm adjusts the directions of nodes to cover the critical targets superiorly and allocates sensing resource among nodes fairly to minimize the coverage difference between nodes. We also propose neighbors sensing scheduling (NSS) protocol based on neighbors´ sensing directions. Through local cover set, NSS identifies a redundant node and decides whether or not it sleeps while taking residual energy to account. Simulation results show the performance of our algorithms.