Zero-Delay Joint Source-Channel Coding for a Bivariate Gaussian on a   Gaussian MAC
  In this paper, delay-free, low complexity, joint source-channel coding (JSCC) for transmission of two correlated Gaussian memoryless sources over a Gaussian Multiple Access Channel (GMAC) is considered. The main contributions of the paper are two distributed JSCC schemes: one discrete scheme based on nested scalar quantization, and one hybrid discrete-analog scheme based on a scalar quantizer and a linear continuous mapping. The proposed schemes show promising performance which improve with increasing correlation and are robust against variations in noise level. Both schemes exhibit a constant gap to the performance upper bound when the channel signal-to-noise ratio gets large. 
Paal Anders Floor, Anna N. Kim, Niklas Wernersson, Tor A. Ramstad,   Mikael Skoglund, Ilangko Balasingham
cs.IT math.IT