Analog mappings for flexible rate transmission of Gaussian sources with side information

This paper considers the problem of designing bandwidth expansion zero-delay analog joint source-channel coding (JSCC) schemes for the transmission of memoryless Gaussian samples over additive white Gaussian noise (AWGN) channels when side information is present at the receiver (Wyner-Ziv scenario). We first propose a 1 : 1 scheme and a 1 : M scheme based on the use of Shannon-Kotel´nikov mappings in a periodic fashion. Then, we combine the two proposed mappings to construct a flexible rate bandwidth expansion mapping whose rate can be anywhere from 1 : 1 to 1 : M. Different from digital systems, the proposed scheme offers low delay, low complexity and high robustness. Simulation results show that the performance of the proposed 1 : 2 scheme is better than that of existing zero-delay systems for a wide range of signal to noise ratios, but especially for high signal to noise ratios and highly correlated side information. The proposed flexible rate bandwidth expansion system also offers satisfactory performance, specially when considering its great flexibleness in terms of rate.