Hybrid Digital-Analog strategies for Source-Channel Broadcast

We consider the problem of transmission of information sources with memory ov er a broadcast channel. This is motivated by the practical application of the des ign of audiovisual broadcast systems for digital TV /digital radio. Using a parallel Gaussian source model and an additive white Gaussian noise broadcast channel model, we consider the problem of information source transmission with the goal of attaining trade-o ffs in meansquare error distortion achieved by individual receivers under a tra nsmission power constraint. Our approach is driven by the high-level recognition that analog (uncoded) and digital (coded) transmission methods o ffer a somewhat complementary set of cost /benefit trade-off options with regard to this problem. Our proposed solution is accordingly motivated at extracting the best of both worlds. Specifically, we invoke a hybr id constructive framework consisting of building blocks derived from a number of tools fr om multi-user information theory – source coding with side information, channel coding with side information, successive refinement source coding and super-position broa dcast channel coding. Our solution delivers interesting quality trade-o ffs for the delivery of colored Gaussian sources over AWGN broadcast channels. When specialized to the case of white source with bandwidth mismatched to the channel bandwidth, our scheme performs as w ell or in some cases strictly better than all currently known strategies