Energy-delay considerations in coded packet flows

Abstract

We consider a line of terminals which is connected by packet erasure channels and where random linear network coding is carried out at each node prior to transmission. In particular, we address an online approach in which each terminal has local information to be conveyed to the base station at the end of the line and provide a queueing theoretic analysis of this scenario. First, a genie-aided scenario is considered and the average delay and average transmission energy depending on the link erasure probabilities and the Poisson arrival rates at each node are analyzed. We then assume that all nodes cannot send and receive at the same time. The transmitting nodes in the network send coded data packets before stopping to wait for the receiving nodes to acknowledge the number of degrees of freedom, if any, that are required to decode correctly the information. We analyze this problem for an infinite queue size at the terminals and show that there is an optimal number of coded data packets at each node, in terms of average completion time or transmission energy, to be sent before stopping to listen.

A Constrained Coding Approach to Error-Free Half-Duplex Relay Networks

“…We note that ON-OFF patterns have also been exploited for neighbor discovery in half-duplex-constrained networks using a compressed sensing approach [8]- [10]. Another problem, namely a line of three nodes where the first two nodes are half-duplex sources and where all nodes are connected by packet erasure channels, was addressed in [11] within a queuing-theoretic framework. In [12] a Gaussian point-topoint channel with a sender subject to a duty cycle constraint (e.g., a half-duplex constraint) and an average power constraint is considered.…”