Patent ID: 7046975

Claim:
A method of demodulating a symbol in a receiver of a communication system without knowledge of the modulation constellation employed in a transmitter to modulate the symbol before transmission, the method comprising: (a) demodulating the symbol according to an assumed modulation constellation; (b) interpreting the modulation symbol as a symbol of one of a family of hierarchical modulation constellations; (c) decoding the demodulated symbol using a forward error correction (FEC) technique; and (d) checking the decoded symbol for correctness, wherein during the interpretation step Mmax−Ks of the symbol bits are applied to the FEC decoder where Mmax denotes the number of symbol bits of highest order modulation constellation, Ks is a value which varies for each assumed modulation constellation according to Ks=Mmax−Ms, where Ms is the number of symbol bits of the respective assumed modulation constellation.