Combined multilevel coding and multiresolution modulation

The performance of a combined multilevel coding and a multiresolution modulation is analyzed. The performance of the system, which depends strongly on the two parameters α₁, α₂ and on the codes is optimized. The optimization is done by considering a hierarchical HDTV transmission where the PV and the TV signals are embedded in the HDTV signal. It is shown that for different receiver conditions one can assume a graceful degradation by using such a combination and obtaining a coding gain at least of about 7.5 dB. This may used for enlarging the broadcasting area or to reduce the transmitter power. For compatible systems one can obtain different receiver complexities, depending on the desired signal quality