MULTIRESOLUTION BROADCAST FOR DIGITAL HDTV USING JOINT SOURCE CHANNELCODING

The use of multiresolution (MR) joint source-channel coding in the con text 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 sho w how a matched multiresolution approach to both source and channel co ding can provide a stepwise graceful degradation. Furthermore, this mu ltiresolution approach improves the behavior, in terms of coverage and robustness of the transmission scheme, over systems that are not spec ifically designed for broadcast situations. This paper examines the al ternatives available for multiresolution transmission through embedded modulation and error correction codes. We also show how multiresoluti on trellis-coded modulation (TCM) can be used to increase coverage ran ge. We present coding results and simulations of noisy transmission. F rom 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 multiresolutio n transmission alternatives.