Digital Network Coding Aided Two-way Relaying: Energy Minimization and Queue Analysis

TL;DR

This paper optimizes energy consumption in a two-way relay network with network coding by allocating resources efficiently and analyzing queue stability using Markov chain models.

Contribution

It introduces an energy minimization framework for two-way relay systems with network coding, including optimal resource allocation and queue analysis methods.

Findings

Optimal resource allocation for energy efficiency identified.

Conditions for superposition coding energy savings derived.

Queue stability analyzed via Markov chain modeling.

Abstract

In this paper, we consider a three node, two-way relay system with digital network coding over static channels where all link gains are assumed to be constant during transmission. The aim is to minimize total energy consumption while ensuring queue stability at all nodes, for a given pair of random packet arrival rates. Specifically, we allow for a set of transmission modes and solve for the optimal fraction of resources allocated to each mode, including multiaccess uplink transmission mode and network coding broadcasting mode. In addition, for the downlink, we find the condition to determine whether superposition coding with excess data over the better link and network coded data for both users is energy efficient and the corresponding optimization is formulated and solved. To tackle the queue evolution in this network, we present a detailed analysis of the queues at each node using a random scheduling method that closely approximates the theoretical design, through a two-dimensional Markov chain model.