Network Coding for Multi-Resolution Multicast

TL;DR

This paper introduces a distributed network coding algorithm for multi-resolution multicast that improves total data rates by combining inter-layer and intra-layer coding, outperforming traditional routing schemes.

Contribution

A novel two-stage pushback algorithm for network coding in multi-resolution multicast that enhances total throughput and guarantees base layer decodability.

Findings

Pushback algorithm outperforms routing and intra-layer coding in simulations.

Performance gap increases with more receivers and network nodes.

Naive inter-layer coding can perform worse than intra-layer schemes under certain conditions.

Abstract

Multi-resolution codes enable multicast at different rates to different receivers, a setup that is often desirable for graphics or video streaming. We propose a simple, distributed, two-stage message passing algorithm to generate network codes for single-source multicast of multi-resolution codes. The goal of this "pushback algorithm" is to maximize the total rate achieved by all receivers, while guaranteeing decodability of the base layer at each receiver. By conducting pushback and code generation stages, this algorithm takes advantage of inter-layer as well as intra-layer coding. Numerical simulations show that in terms of total rate achieved, the pushback algorithm outperforms routing and intra-layer coding schemes, even with codeword sizes as small as 10 bits. In addition, the performance gap widens as the number of receivers and the number of nodes in the network increases. We also observe that naiive inter-layer coding schemes may perform worse than intra-layer schemes under certain network conditions.