Characterization of Random Linear Network Coding with Application to Broadcast Optimization in Intermittently Connected Networks

TL;DR

This paper analyzes the performance of random linear network coding in intermittently connected mobile networks, revealing underutilization issues and proposing an improved protocol to significantly boost throughput with minimal delay.

Contribution

It provides a novel analysis linking RLNC to message selection strategies and introduces an enhanced forwarding protocol for better throughput in challenging network environments.

Findings

RLNC is equivalent to a random message selection strategy with buffer exchange.

Network coding is often underutilized in intermittent networks.

Proposed protocol significantly increases throughput with negligible delay.

Abstract

We address the problem of optimizing the throughput of network coded traffic in mobile networks operating in challenging environments where connectivity is intermittent and locally available memory space is limited. Random linear network coding (RLNC) is shown to be equivalent (across all possible initial conditions) to a random message selection strategy where nodes are able to exchange buffer occupancy information during contacts. This result creates the premises for a tractable analysis of RLNC packet spread, which is in turn used for enhancing its throughput under broadcast. By exploiting the similarity between channel coding and RLNC in intermittently connected networks, we show that quite surprisingly, network coding, when not used properly, is still significantly underutilizing network resources. We propose an enhanced forwarding protocol that increases considerably the throughput for practical cases, with negligible additional delay.