Robust Joint Source-Channel Coding for Delay-Limited Applications

TL;DR

This paper introduces a new robust joint source-channel coding scheme for delay-limited Gaussian channels that achieves optimal signal-to-distortion slope and maintains a bounded gap to the ideal SDR curve, highlighting fundamental limits.

Contribution

It proposes a novel coding scheme with optimal SDR slope and a family of codes close to the theoretical performance bounds for delay-limited scenarios.

Findings

Achieves the optimal slope of the SDR curve.

Provides a family of codes with bounded gap to the optimal SDR.

Shows unbounded performance loss for delay-limited hybrid digital-analog codes.

Abstract

In this paper, we consider the problem of robust joint source-channel coding over an additive white Gaussian noise channel. We propose a new scheme which achieves the optimal slope of the signal-to-distortion (SDR) curve (unlike the previously known coding schemes). Also, we propose a family of robust codes which together maintain a bounded gap with the optimum SDR curve (in terms of dB). To show the importance of this result, we drive some theoretical bounds on the asymptotic performance of delay-limited hybrid digital-analog (HDA) coding schemes. We show that, unlike the delay-unlimited case, for any family of delay-limited HDA codes, the asymptotic performance loss is unbounded (in terms of dB).