Low-Latency Source-Channel Coding for Fading Channels with Correlated Interference

We investigate the problem of sending a Gaussian source over a Rayleigh fading channel with Gaussian correlated interference known to the transmitter using low-latency codes. For the matched bandwidth case between the source and the channel, we show that among all single-letter codes, the uncoded scheme achieves the lowest mean square error distortion under full correlation between source and interference, and hence it is optimal. To benefit from nonlinear strategies for other scenarios, we derive the necessary conditions for optimality and propose an iterative algorithm based on joint optimization between the encoder and the decoder. A reduced-complexity approach for the implementation of the design algorithm is presented based on Monte-Carlo (at the encoder side) and importance sampling (at the decoder side) techniques. Furthermore, the scalability of our low-latency scheme is improved by modifying the search process at the encoder side using a targeted search method.