Multiresolution joint source-channel coding using embedded constellations for power-constrained time-varying channels

CONSTELLATIONS FOR POWER-CONSTRAINED TIME-VARYING CHANNELS. Igor Kozintsev Kannan Ramchandran Beckman Institute and ECE Dept. University of Illinois at Urbana-Champaign, Urbana, IL 61801 [email protected], [email protected] ABSTRACT We explore joint source-channel coding (JSCC) for time-varying (slow-fading Rayleigh) channels, using a multiresolution (MR) framework for both source coding and transmission (via a novel MR modulation constellation). We tackle the important case of informed receiver but uninformed transmitter, i.e. where the receiver has access to the channel state information (CSI), but the transmitter does not. We describe an algorithm which jointly optimizes the design of the MR source codebook, the MR constellation, and the decoding strategy of optimally matching the source and signal constellation resolution trees according to the time-varying channel, and show how this leads to improved performance over separately designed source and channel coders.