Possible coding and modulation approaches to improve service availability for digital HDTV satellite broadcasting at 22 GHz

Novel coding/modulation approaches for improving the service availability of digital HDTV (high-definition television) satellite broadcasting services at 22 GHz are considered. Two possible approaches are described which use the concept of layered modulation in conjunction with layered picture coding and channel coding. By means of this technique, the service continuity can be extended without the needs to increase the satellite transmitted power, the service quality under severe atmospheric attenuations being reduced from high definition to normal definition. Most of the time, e.g., for up to 99% of the worst month, the service provides nominal HDTV quality, while during heavy rain fades the receiver decodes the normal TV picture