Directional antennas MAC protocol for energy-efficient wireless sensor networks with mobile sink.

Using mobile sink with directional antennas (DAs) is one of the major efforts in the literature to improve energy efficiency in wireless sensor networks (WSNs). However, there are three important concerns that have remained unresolved when utilizing this method: namely, (i) packets may be lost because of the continuous motion of the mobile sink; (ii) energy may be wasted when the mobile sink is transiting from one point to another; and (iii) the antennas may not completely scan the entire vicinity of the mobile sink because of continuous directional motion. Our research for this paper targeted these three concerns. For this purpose, a novel semi-Markov decision process-based model is constructed for energy-efficient WSNs with a mobile sink using DAs. Optimal results in terms of the average optimal value of the sum of expected total discounted energy consumption is achieved. Through this optimal analysis, the conclusion is reached that packet loss due to the continuous directional motion of the mobile sink will be eliminated, energy will be preserved, and the mobile sink will completely scan its vicinity using the four DAs. Our results may provide guidelines for using mobile sinks with DAs to further improve energy efficiency in WSNs. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]