Improved Algorithms in Directional Wireless Sensor Networks

Recent advances in wireless sensor networks (WSNs) allow directional antennas to be used instead of omni-directional antennas. However, the problem of maintaining (symmetric) connectivity in directional wireless sensor networks (DWSNs) is significantly harder. Contributing to this field of research, in this paper, we study the Antenna Orientation problem in WSNs equipped with k directional antennas (3 <= k <= 4). Antenna Orientation (AO) is the problem that given a set S of nodes equipped with omni-directional antennas of unit range, the goal is to replace omni-directional antennas by directional antennas with beam-width theta >= 0 and to find a way to orient them such that the required range r to yield a symmetric connected communication graph (SCCG) is minimized. For this problem, we propose an O(n log n) time algorithm yielding r = 2sin (180 degrees/k). Our results show that the proposed algorithms achieve good performance in both theory and practice.