Date Added: Jan 2012
In this paper, the authors focus on a roadside directional sensor network where sensors with directional Field Of Views (FOVs) are placed along a roadway. They study the problem of wakeup scheduling, with the objective of maximizing network lifetime under the constraint that full coverage and network connectivity are maintained at all times. First, they present centralized polynomial time algorithms to optimally solve the problems of scheduling sensor nodes with fixed sensing orientations. Moreover, an effective heuristic algorithm is proposed to solve the problem of scheduling sensor nodes with variable sensing orientations. In addition, they also present distributed algorithms for both fixed and variable cases.