Talk Half Listen To Half: An Energy-Efficient Neighbor Discovery Protocol in Wireless Sensor Networks

Abstract

Due to the combination of constrained power, low duty cycle, and high mobility, neighbor discovery is one of the most challenging problems in wireless sensor networks. Existing discovery designs can be divided into two types: pairwise-based and group-based. The former schemes suffer from high discovery delay, while the latter ones accelerate the discovery process but increase transmission package size or incur too much energy overhead, far from practical. Guided by the Talk More Listen Less (TMLL) principle (published in 2016), in which beacons are not necessarily placed in the wakeup slots, we propose two different versions of a group-based protocol we called Talk Half Listen Half (THLH). For the first time, a group-based protocol uses the Channel Occupancy Rate (COR), one of the fundamental novel components of the TMLL model, for performance improvements, in the same way, Duty Cycle (DC) was used in previous group-based protocols. Both versions of the protocol use low transmission overhead in comparison with previous group-based discoveries. After analyzing pros and cons of each approach, we arrived at the conclusion that both behave the best for networks where the average number of new neighbors per slot (β) is low, a metric that sets the bases for performance comparisons of any current/future work with variable COR usage. We also derived a formula that links this new metric with the worst case avg. COR usage of our proposed protocols. Finally, simulation results show that our protocol can improve the average discovery latency and worst case latency close to 50% given low β values.