Multiresolution broadcast for digital HDTV using joint source-channel coding

In the context of digital terrestrial broadcast of high-definition television (HDTV), the use of multiresolution joint source-channel coding is shown to provide an attractive alternative to traditional single resolution (SR) digital techniques. While SR schemes suffer from a sharp threshold effect in the fringes of the broadcast area, it is shown that a matched multiresolution approach to both source and channel coding can provide a stepwise graceful degradation. Furthermore, this multiresolution approach improves the behavior, in terms of coverage and robustness of the transmission scheme, over systems that are not specifically designed to broadcast situations. The authors examine the alternatives available for multiresolution transmission, through embedded modulation, possibly trellis-coded to increase coverage range. From a systems point of view, they also discuss the tradeoffs involved in the choice of coverage areas for the low- and high-resolution signals