Signal points from a PCM-derived constellation are selected for transmission via a modulation technique which employs different levels of redundancy coding--including the possibility of no redundancy coding--for respective different sub-constellations of the overall PCM-derived constellation. The coding...http://www.google.com/patents/US5953376?utm_source=gb-gplus-sharePatent US5953376 - Probabilistic trellis coded modulation with PCM-derived constellations
