Multi-Way Relay Networks: Orthogonal Uplink, Source-Channel Separation and Code Design

TL;DR

This paper investigates reliable communication in multi-way relay networks with orthogonal uplinks and correlated sources, providing a theoretical characterization, a separation theorem for two nodes, and a practical coding scheme with performance analysis.

Contribution

It offers a single-letter characterization of reliable communication, proves a separation theorem for two nodes, and proposes a practical LDPC-based coding scheme with performance analysis.

Findings

Single-letter expression for reliable communication

Separation theorem for two-node networks

LDPC-based coding scheme with density evolution analysis

Abstract

We consider a multi-way relay network with an orthogonal uplink and correlated sources, and we characterise reliable communication (in the usual Shannon sense) with a single-letter expression. The characterisation is obtained using a joint source-channel random-coding argument, which is based on a combination of Wyner et al.'s "Cascaded Slepian-Wolf Source Coding" and Tuncel's "Slepian-Wolf Coding over Broadcast Channels". We prove a separation theorem for the special case of two nodes; that is, we show that a modular code architecture with separate source and channel coding functions is (asymptotically) optimal. Finally, we propose a practical coding scheme based on low-density parity-check codes, and we analyse its performance using multi-edge density evolution.