Patent ID: 7111221

Claim:
A digital signal transmission system for transmitting encoded bit streams including a normal bit stream and a robust bit stream, said system comprising: first forward error correction (FEC) unit for encoding the normal bit stream and the robust bit stream; a robust processor unit for receiving and processing said encoded robust bit stream to generate a processed robust bit stream and passing through said encoded normal bit stream as an unaltered encoded normal bit stream; a trellis encoder unit for receiving the unaltered encoded normal bit stream and the processed robust bit stream, and for producing a stream of trellis encoded data bits corresponding to bits of said unaltered encoded normal bit stream and bits of said processed robust bit stream; a second forward error correction (FEC) unit for reading in only portions of said trellis encoded data bits corresponding to said bits of said processed robust bit stream from the trellis encoder unit and enabling generation of parity bytes only for said processed robust bit stream; and a transmitter device for transmitting said stream of trellis encoded data bits corresponding to said bits of said unaltered encoded normal bit stream and said bits of said processed robust bit stream including said parity bytes over a communication channel to a receiver device.