Approximation and Heuristic Algorithms for Computing Backbones in Asymmetric Ad-Hoc Networks

TL;DR

This paper introduces new approximation and heuristic algorithms for efficiently computing minimal strongly connected dominating-absorbent sets, or backbones, in asymmetric wireless ad-hoc networks modeled as disk graphs, with practical distributed solutions.

Contribution

It presents the first distributed approximation algorithm with a constant factor and a simple heuristic, validated through extensive simulations.

Findings

Distributed approximation algorithm has a constant approximation factor.

Heuristic algorithm outperforms previous methods in simulations.

Algorithm runs in O(Diam) time, scalable to network size.

Abstract

We consider the problem of dominating set-based virtual backbone used for routing in asymmetric wireless ad-hoc networks. These networks have non-uniform transmission ranges and are modeled using the well-established disk graphs. The corresponding graph theoretic problem seeks a strongly connected dominating-absorbent set of minimum cardinality in a digraph. A subset of nodes in a digraph is a strongly connected dominating-absorbent set if the subgraph induced by these nodes is strongly connected and each node in the graph is either in the set or has both an in-neighbor and an out-neighbor in it. Distributed algorithms for this problem are of practical significance due to the dynamic nature of ad-hoc networks. We present a first distributed approximation algorithm, with a constant approximation factor and O(Diam) running time, where Diam is the diameter of the graph. Moreover we present a simple heuristic algorithm and conduct an extensive simulation study showing that our heuristic outperforms previously known approaches for the problem.