Patent ID: 7555052

Claim:
A method of performing turbo trellis coded modulation (TTCM) on an n bit information word in a discrete multitone (DMT) system comprising: passing at least one least significant bit of the n bit information word into a redundant bit turbo-engine to generate an m bit code word, wherein passing the at least one information bits into the redundant bit turbo-engine comprises splitting the at least one least significant bit into duplicate first and second serial data streams, passing the first serial data stream through a first systematic recursive encoder and passing the second serial data stream through a second systematic recursive encoder preceded by an interleaver; alternately selecting bits output from the first and second systematic recursive encoders to form an m-bit serial data stream; converting the m-bit serial data stream into the m-bit code word through serial to parallel conversion; appending the m-bit code word to the n bit information word at the least significant bit position to create an (n+m) bit codeword v; and preparing the codeword v for transmission over a communications channel, wherein the (n+m) bit code is mapped onto two identical 2 dimensional 8-QAM constellation mappings.