Optimal Radius for Connectivity in Duty-Cycled Wireless Sensor Networks

TL;DR

This paper determines the optimal transmission radius for ensuring connectivity in duty-cycled wireless sensor networks, proving a new necessary and sufficient condition and validating it through simulations.

Contribution

It introduces a new vertex-based random connection model and establishes an optimal radius condition for connectivity in duty-cycled WSNs, settling a prior conjecture.

Findings

Derived a weak sufficient condition for connectivity in DC-WSN.

Proved the existence of a finite component of size >1 approaches zero at high density.

Designed a minimum-radius duty-cycling scheme close to the theoretical optimal radius.

Abstract

We investigate the condition on transmission radius needed to achieve connectivity in duty-cycled wireless sensor networks (briefly, DC-WSN). First, we settle a conjecture of Das et. al. (2012) and prove that the connectivity condition on Random Geometric Graphs (RGG), given by Gupta and Kumar (1989), can be used to derive a weak sufficient condition to achieve connectivity in DC-WSN. To find a stronger result, we define a new vertex-based random connection model which is of independent interest. Following a proof technique of Penrose (1991) we prove that when the density of the nodes approaches infinity then a finite component of size greater than 1 exists with probability 0 in this model. We use this result to obtain an optimal condition on node transmission radius which is both necessary and sufficient to achieve connectivity and is hence optimal. The optimality of such a radius is also tested via simulation for two specific duty-cycle schemes, called the contiguous and the random selection duty-cycle scheme. Finally, we design a minimum-radius duty-cycling scheme that achieves connectivity with a transmission radius arbitrarily close to the one required in Random Geometric Graphs. The overhead in this case is that we have to spend some time computing the schedule.