  In this paper, communication of a Multivariate Gaussian over a Gaussian
Multiple Access Channel is studied. Distributed zero-delay joint source-channel
coding (JSCC) solutions to the problem are given. Both nonlinear and linear
approaches are discussed. The performance upper bound (signal-to-distortion
ratio) for arbitrary code length is also derived and Zero-delay cooperative
JSCC is briefly addressed in order to provide an approximate bound on the
performance of zero-delay schemes. The main contribution is a nonlinear hybrid
discrete-analog JSSC scheme based on distributed quantization and a linear
continuous mapping named Distributed Quantizer Linear Coder (DQLC). The DQLC
has promising performance which improves with increasing correlation, and is
robust against variations in noise level. The DQLC exhibits a constant gap to
the performance upper bound as the signal-to-noise ratio (SNR) becomes large
for any number of sources and values of correlation. Therefore it outperforms a
linear solution (uncoded transmission) in any case when the SNR gets
sufficiently large.
