Joint Source-Channel Coding Via Model Predictive Control

We propose a joint source-channel coding (JSCC) scheme based on model-predictive control (MPC) for encoding an analog discrete-time source over a memoryless communication channel. The decoder is assumed to be fixed and given, and the MPC encoder is set to minimize the frequency-weighted mean-squared error (FWMSE) while satisfying a channel input constraint. We derive analytic expressions for the associated finite-horizon optimization MPC problem for an asymptotic (in time) average or sum channel input constraint. For the case of complex additive white Gaussian noise channel and an M-quadrature-amplitude modulation (M-QAM) decoder, these expressions can be written explicitly, which allows for an efficient numerical solution. For the case M=4 and considering a frequency weighting criterion that models the sensitivity of the human hearing, we show by simulations that our proposed scheme yields an FWMSE significantly smaller than that yielded by the corresponding non-JSCC scheme (a 2-bit uniform quantizer in tandem with a 4-QAM channel encoder and decoder). (C) 2021 Published by Elsevier Ltd on behalf of European Control Association.