Limits on the Robustness of MIMO Joint Source-Channel Codes

TL;DR

This paper investigates the fundamental limits of robustness in MIMO joint source-channel coding, revealing significant gaps between achievable and optimal diversity-fidelity tradeoffs under robustness constraints.

Contribution

It characterizes the asymptotic performance limits of robust MIMO joint source-channel codes using upper bounds on the diversity-fidelity tradeoff.

Findings

Significant gap between robust and optimal tradeoffs.

Upper bounds on diversity-fidelity tradeoff established.

Robust codes cannot achieve the same performance as non-robust ones.

Abstract

In this paper, the theoretical limits on the robustness of MIMO joint source channel codes is investigated. The case in which a single joint source channel code is used for the entire range of SNRs and for all levels of required fidelity is considered. Limits on the asymptotic performance of such a system are characterized in terms of upper bounds on the diversity-fidelity tradeoff, which can be viewed as an analog version of the diversity-multiplexing tradeoff. In particular, it is shown that there is a considerable gap between the diversity-fidelity tradeoff of robust joint source-channel codes and the optimum tradeoff (without the constraint of robustness).