MULTIRESOLUTION BROADCAST FOR DIGITAL HDTV USING JOINT SOURCE CHANNEL CODING

The use of multiresolution (MR) joint source-channel coding in the context of digital terrestrial broadcasting of high definition television (HDTV) is shown to be an efficient alternative to traditional single-resolution techniques. While the single-resolution schemes suffer from a sharp threshold effect in the fringes of the broadcast area, we show how 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 for broadcast situations. This paper examines the alternatives available for multiresolution transmission through embedded modulation and error correction codes. We also show how multiresolution trellis-coded modulation (TCM) can be used to increase coverage range. We present coding results and simulations of noisy transmission. From a systems point of view, we also discuss the tradeoffs involved in the choice of the low- and high-resolution coverage areas as well as the comparative costs and complexities of the different multiresolution transmission alternatives.