Method and apparatus for error correction in multi-line multi-tone gigabit transmission systems

1. 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.

2. The multi-tone modem of claim 1 , wherein further:

the cross-channel forward error correction module includes responsiveness to an error signal received on one of the communication channels to inject a corresponding one of the cross-channel redundancy symbols identified by the error signal into at least one of the communication channels transmitted by the multi-tone modem.

3. The multi-tone modem of claim 1 , wherein further:

the cross-channel forward error correction module configured to inject the buffered cross-channel redundancy symbols into at least one of the communication channels transmitted by the multi-tone modem.

4. The multi-tone modem of claim 1 , wherein the at least one in-channel forward error correction component further comprises:

at least one switch for switchably coupling each in-channel FEC decoder to the cross-channel FEC decoder responsive to an error condition of the in-channel codewords of one or more channels thereby switchably forming a feedback loop between the in-channel FEC decoder components and the cross-channel FEC decoder module which combines the two orthogonal FEC decoders with one another to recover the error codeword(s).

5. A means for error correction in a multi-tone modem configured to transmit and receive communication channels each associated with a corresponding one of a plurality of transmission lines, and the means comprising:

means for discretely encoding and decoding in-channel codewords from each of the communication channels transmitted and received over the plurality of transmission lines;

means for cross-channel encoding cross-channel codewords across all communication channels;

means for detecting an error condition resulting from errored codewords in the decoding of in-channel codewords in the act of discretely encoding and decoding in-channel codewords; and responsive thereto:

means for decoding un-recoverable in-channel errored codewords with corresponding cross-channel codeword counterparts encoded by the means for cross-channel encoding; and

means for mapping back resultant decoded cross-channel codewords to corresponding in-channel counterparts for another round of in-channel decoding; thereby recovering errored codewords by exploiting orthogonality between the in-channel and cross-channel codewords.

6. The means for error correction of claim 5 , further comprising:

means for injecting a corresponding one of the cross-channel redundancy symbols identified by the error signal into at least one of the communication channels transmitted by the multi-tone modem, responsive to an error signal received on one of the communication channels.