Distortion exponent in fading MIMO channels with time-varying side information

Abstract

The joint source-channel coding problem of sending a Gaussian source over a multiple input-multiple output (MIMO) fading channel with time-varying correlated side information at the decoder is studied. A block fading model for both the channel and the side information qualities is considered, and perfect (channel and side information) state information at the receiver is assumed, while the transmitter has only a statistical knowledge. In particular, the high SNR performance is studied by deriving the distortion exponent of various transmission schemes. An upper bound on the distortion exponent is derived by providing the channel state to the encoder while the side information state remains unknown. Separate source and channel coding is considered as well as joint decoding at the receiver. The joint decoding scheme is extended to multiple digital layers. Finally, a hybrid digital-analog (HDA) scheme is analyzed. While the optimal distortion exponent is completely characterized for MISO/SIMO channels, for general MIMO channels, the optimal distortion exponent is characterized in the small bandwidth ratio regime.