Duty-Cycle-Aware Minimum-Energy Multicasting in Wireless Sensor Networks

TL;DR

This paper addresses the complex problem of energy-efficient multicasting in duty-cycled wireless sensor networks by formulating a new problem, proving its computational hardness, and proposing an effective approximation algorithm with distributed implementation.

Contribution

The paper introduces the MEMTCS problem for duty-cycled networks, proves its NP-hardness, and provides a polynomial-time approximation algorithm with a distributed version.

Findings

The proposed algorithm achieves a performance ratio of O(H(Δ+1)).

Simulation results show significant energy savings over existing algorithms.

The algorithm reduces transmission redundancy and total energy cost.

Abstract

In duty-cycled wireless sensor networks, the nodes switch between active and dormant states, and each node may determine its active/dormant schedule independently. This complicates the Minimum-Energy Multicasting (MEM) problem, which has been primarily studied in always-active wireless ad-hoc networks. In this paper, we study the duty-cycle-aware MEM problem in wireless sensor networks, and we present a formulation of the Minimum-Energy Multicast Tree Construction and Scheduling (MEMTCS) problem. We prove that the MEMTCS problem is NP-hard, and it is unlikely to have an approximation algorithm with a performance ratio of $(1-o(1))\ln\Delta$, where $\Delta$ is the maximum node degree in a network. We propose a polynomial-time approximation algorithm for the MEMTCS problem with a performance ratio of $\mathcal{O}(H(\Delta+1))$, where $H(\cdot)$ is the harmonic number. We also provide a distributed implementation of our algorithm. Finally, we perform extensive simulations and the results demonstrate that our algorithm significantly outperform other known algorithms in terms of both the total energy cost and the transmission redundancy.