Hybrid Coding for Gaussian Broadcast Channels with Gaussian Sources

TL;DR

This paper demonstrates that hybrid coding achieves optimal or improved distortion regions in Gaussian broadcast channels with Gaussian sources, outperforming separate source-channel coding especially for correlated sources at lower SNRs.

Contribution

It establishes the optimality of hybrid coding for independent sources and shows its advantages over separate coding for correlated sources in Gaussian broadcast channels.

Findings

Hybrid coding achieves the optimal distortion region for independent sources.

Uncoded transmission is suboptimal in this setting.

Hybrid coding outperforms separate coding for correlated sources below a certain SNR.

Abstract

This paper considers a degraded Gaussian broadcast channel over which Gaussian sources are to be communicated. When the sources are independent, this paper shows that hybrid coding achieves the optimal distortion region, the same as that of separate source and channel coding. It also shows that uncoded transmission is not optimal for this setting. For correlated sources, the paper shows that a hybrid coding strategy has a better distortion region than separate source-channel coding below a certain signal to noise ratio threshold. Thus, hybrid coding is a good choice for Gaussian broadcast channels with correlated Gaussian sources.