Analog index coding over block-fading MISO broadcast channels with feedback

We define an “analog” index coding problem where a transmitter wishes to send a set of analog sources to be reconstructed with a desired distortion level at K receivers, each of which is characterized by a set of desired sources and by its own side information. The transmission channel is a multi-input single-output (MISO) broadcast channel with independent fading, perfect channel state information at the receiver and (strictly causal) feedback at the transmitter. An outer bound on the rate-distortion region is derived, revealing an interesting tradeoff between the communication rate (source samples per channel use) and the distortion exponential decay with snr in dB. We focus on the high-SNR and low-distortion regime, in which the proposed outer bound is shown to be tight for some cases of particular interest.