Patent ID: 7532666

Claim:
A multi-tone modem configured to transmit and receive communication channels each associated with a corresponding one of a plurality of transmission lines, the multi-tone modem comprising: at least one in-channel forward error correction (FEC) component discretely encoding and decoding data from each communication channels transmitted and received over the plurality of transmission lines; a cross-channel forward error correction module encoding data from all communication channels and buffering the corresponding cross-channel redundancy symbols of each resulting cross-channel codeword; and a cross-channel FEC decoder responsive to an in-channel error condition to cross-map and decode un-recoverable in channel errored codewords with corresponding cross-channel codeword counterparts and to map back resultant decoded cross-channel codewords to corresponding in-channel counterparts for input to the at least one in-channel FEC correction component for another round of in-channel FEC decoding; whereby errored codewords are recovered by exploiting orthogonality between the in-channel and cross-channel FEC decoders.