Slepian-Wolf Coding for Broadcasting with Cooperative Base-Stations

TL;DR

This paper introduces a cooperative base-station broadcasting model with two operational modes, establishing the theoretical limits and optimal coding strategies for each, leveraging hash-and-forward and helper source coding techniques.

Contribution

It develops a new information-theoretic framework for cooperative broadcasting with helper base stations, including optimal coding schemes and a duality between operational modes.

Findings

Optimal hash-and-forward coding in Mode 1

Source coding with helper sources in Mode 2

Operational duality between the two modes

Abstract

We propose a base-station (BS) cooperation model for broadcasting a discrete memoryless source in a cellular or heterogeneous network. The model allows the receivers to use helper BSs to improve network performance, and it permits the receivers to have prior side information about the source. We establish the model's information-theoretic limits in two operational modes: In Mode 1, the helper BSs are given information about the channel codeword transmitted by the main BS, and in Mode 2 they are provided correlated side information about the source. Optimal codes for Mode 1 use \emph{hash-and-forward coding} at the helper BSs; while, in Mode 2, optimal codes use source codes from Wyner's \emph{helper source-coding problem} at the helper BSs. We prove the optimality of both approaches by way of a new list-decoding generalisation of [8, Thm. 6], and, in doing so, show an operational duality between Modes 1 and 2.