Uncoded transmission of correlated Gaussian sources over broadcast channels with feedback

Abstract

Motivated by the practical requirement for delay and complexity constrained broadcasting, we study uncoded transmission of a pair of correlated Gaussian sources over a two-user Gaussian broadcast channel with unit-delay noiseless feedback links (GBCF). Differently from previous works, in the present work we focus on the finite horizon regime. We present two joint source-channel coding schemes, one is based on the Ozarow-Leung (OL) coding scheme for the GBCF and the other is based on the linear quadratic Gaussian (LQG) code by Ardestanizadeh et al. Our LQG-oriented code uses an improved decoder which outperforms the original decoder of Ardestanizadeh et al. in the finite horizon regime. We further derive lower and upper bounds on the minimal number of channel uses needed to achieve a specified pair of distortion levels for each scheme, and using these bounds, we explicitly characterize a range of transmit powers in which the OL code outperforms the LQG-oriented code.