Wyner-Ziv Coding over Broadcast Channels: Digital Schemes

TL;DR

This paper proposes a digital layered coding scheme for lossy source transmission over broadcast channels with correlated side information, analyzing its performance in Gaussian and binary cases and identifying optimal strategies based on receiver quality.

Contribution

It introduces a novel layered digital coding scheme combining Slepian-Wolf and dirty paper coding for broadcast channels with side information, providing analysis and optimality conditions.

Findings

The scheme is optimal when all receivers have equal overall quality.

Sending refinement information to the better receiver improves overall quality.

The scheme's effectiveness varies with receiver quality and channel parameters.

Abstract

This paper addresses lossy transmission of a common source over a broadcast channel when there is correlated side information at the receivers, with emphasis on the quadratic Gaussian and binary Hamming cases. A digital scheme that combines ideas from the lossless version of the problem, i.e., Slepian-Wolf coding over broadcast channels, and dirty paper coding, is presented and analyzed. This scheme uses layered coding where the common layer information is intended for both receivers and the refinement information is destined only for one receiver. For the quadratic Gaussian case, a quantity characterizing the overall quality of each receiver is identified in terms of channel and side information parameters. It is shown that it is more advantageous to send the refinement information to the receiver with "better" overall quality. In the case where all receivers have the same overall quality, the presented scheme becomes optimal. Unlike its lossless counterpart, however, the problem eludes a complete characterization.