Dynamic Slot-Length Control for Reducing Neighbor Discovery Latency in Wireless Sensor Networks

The state of art protocols in neighbor discovery in wireless sensor networks can be divided into two categories: the quorum based, and the co-primality based protocols, which are confirmed by simulations to have a small "theoretical" latency according to their wake-up schedule designs. However, these works fail to consider the collision of neighbor discovery beacons, when multiple pairs of nodes search for discovery simultaneously, which could lead to a greater "practical" latency. In this paper, we seek to reduce such practical latency in neighbor discovery protocols caused by the collision of neighbor discovery beacons by a dynamic slot-length control mechanism that allows each node to autonomously vary its slot length based on the detection of beacon collisions. We develop a real-world testbed of neighbor discovery on Android smartphones by implementing a few classic neighbor discovery protocols in literature, and evaluate their performance with and without the proposed slot-length control. Experimental results show that the slot-length control can help reduce the practical latency of neighbor discovery by more than 15% under both types of neighbor discovery protocols.