Space-time design for deep joint source channel coding of images Over MIMO channels

TL;DR

This paper introduces deep joint source-channel coding algorithms for wireless image transmission over MIMO channels, leveraging space-time design to improve robustness and efficiency under different channel conditions.

Contribution

It presents two novel schemes exploiting MIMO diversity and multiplexing gains for deep JSCC, with detailed analysis and performance comparisons.

Findings

Diversity scheme outperforms multiplexing at low SNR and fewer receive antennas.

Both schemes achieve performance close to the channel's capacity bound.

Full-diversity scheme is less beneficial with more than two transmit antennas.

Abstract

We propose novel deep joint source-channel coding (DeepJSCC) algorithms for wireless image transmission over multi-input multi-output (MIMO) Rayleigh fading channels, when channel state information (CSI) is available only at the receiver. We consider two different schemes; one exploiting the spatial diversity and the other exploiting the spatial multiplexing gain of the MIMO channel, respectively. For the former, we utilize an orthogonal space-time block code (OSTBC) to achieve full diversity and increase the robustness against channel variations. In the latter, we directly map the input to the antennas, where the additional degree of freedom can be used to send more information about the source signal. Simulation results show that the diversity scheme outperforms the multiplexing scheme for lower signal-to-noise ratio (SNR) values and a smaller number of receive antennas at the AP. When the number of transmit antennas is greater than two, however, the full-diversity scheme becomes less beneficial. We also show that both the diversity and multiplexing schemes can achieve comparable performance with the state-of-the-art BPG algorithm delivered at the instantaneous capacity of the MIMO channel, which serves as an upper bound on the performance of separation-based practical systems.