Self-Stabilizing Robots in Highly Dynamic Environments

TL;DR

This paper presents a self-stabilizing algorithm for exploring highly dynamic rings with robots, ensuring perpetual node visitation despite unpredictable edge changes, by characterizing the minimum number of robots needed for different ring sizes.

Contribution

It provides a complete characterization of the minimum number of robots required to solve the exploration problem in highly dynamic rings, with a self-stabilizing approach.

Findings

Determines necessary and sufficient robot counts for ring exploration.

Proposes a self-stabilizing algorithm resilient to dynamic environments.

Ensures perpetual exploration despite unpredictable edge changes.

Abstract

This paper deals with the classical problem of exploring a ring by a cohort of synchronous robots. We focus on the perpetual version of this problem in which it is required that each node of the ring is visited by a robot infinitely often. The challenge in this paper is twofold. First, we assume that the robots evolve in a highly dynamic ring, \ie edges may appear and disappear unpredictably without any recurrence, periodicity, nor stability assumption. The only assumption we made (known as temporal connectivity assumption) is that each node is infinitely often reachable from any other node. Second, we aim at providing a self-stabilizing algorithm to the robots, i.e., the algorithm must guarantee an eventual correct behavior regardless of the initial state and positions of the robots.In this harsh environment, our contribution is to fully characterize, for each size of the ring, the necessary and sufficient number of robots to solve deterministically the problem.