Synchronization scheme in a turbo decoder based FEC system

An apparatus adapted to determine synchronization between incoming data and turbo frame boundaries in a turbo decoder based forward error correction system, said system comprising a turbo decoder adapted to receive incoming data and provide a turbo decoder output, an optional deinterleaver adapted to receive said turbo decoder output and provide a deinterleaver output, and an optional block code decoder adapted to receive said deinterleaver output and provide a block code decoder output, the apparatus comprising:

• a conditional synchronizer module, adapted to provide a first synchronization check of said incoming data frame markers to said turbo decoder, and being further adapted to declare conditional synchronization if a first condition is met, said declaration being required to allow transfer of data to said turbo decoder;
• an optional first sync check module, adapted to provide a second synchronization check of sync bytes from said turbo decoder output, and being further adapted to reset said conditional synchronization declaration if a second condition is not met;
• and
• an optional second sync check module, adapted to provide a third synchronization check of error sets from said block decoder output, and being further adapted to reset said conditional synchronization declaration if a third condition is met;
• and
• wherein said conditional synchronizer module is further adapted to repeat said first synchronization check if said conditional synchronization declaration is reset.

A method for determining synchronization between incoming data and turbo frame boundaries in a turbo decoder based forward error correction system, said system comprising a turbo decoder adapted to receive incoming data and provide a turbo decoder output, an optional deinterleaver adapted to receive said turbo decoder output and provide a deinterleaver output, and an optional block code decoder adapted to receive said deinterleaver output and provide a block code decoder output, the method comprising:

• performing a first synchronization check at said system turbo decoder input by monitoring said incoming data to said turbo decoder and declaring conditional synchronization if X+1 data sets in a row each have less than or equal to e errors, said declaration being required to allow transfer of data to said turbo decoder, and wherein said variables X and e are selectable;
• performing optionally one or both of the following two operations:
• a second synchronization check at said system turbo decoder output comprising monitoring said turbo decoder output and declaring first sync if S sync bytes in a row from said turbo decoder output match Y+5 bits of a total number of bits U and resetting said conditional synchronization declaration if first sync not declared, and wherein said variables S, Y and U are selectable;
• and
• a third synchronization check at said system block code decoder output comprising monitoring said block decoder output and resetting said conditional synchronization declaration if said block decoder generates Z error sets in a row, where each said error set is T or more uncorrectable frames of a total number of frames V, said variables Z, T and V are selectable;
• and
• repeating said first synchronization check if said conditional synchronization declaration is reset.

An apparatus for determining synchronization between incoming data and turbo frame boundaries in a turbo decoder based forward error correction system, said system comprising a turbo decoder adapted to receive incoming data and provide a turbo decoder output, an optional deinterleaver adapted to receive said turbo decoder output and provide a deinterleaver output, and an optional block code decoder adapted to receive said deinterleaver output and provide a block code decoder output, the apparatus comprising:

• a conditional synchronizer module, adapted to provide a first synchronization check at said system turbo decoder input, and being further adapted to monitor said incoming data to said turbo decoder and declare conditional synchronization if X+1 data sets in a row each have less than or equal to e errors, said declaration being required to allow transfer of data to said turbo decoder, said variables X and e are selectable;
• an optional first sync check module, adapted to monitor said turbo decoder output and declare first sync if S sync bytes in a row from said turbo decoder output match Y+5 bits of a total number of bits U, and being further adapted to reset said conditional synchronization declaration if first sync not declared, said variables S, Y and U are selectable;
• and
• an optional second sync check module, adapted to monitor said block decoder output and reset said conditional synchronization declaration if said block decoder generates Z error sets in a row, where each said error set is T or more uncorrectable frames of a total number of frames V, said variables Z, T and V are selectable;
• and
• wherein said conditional synchronizer module is further adapted to repeat said first synchronization check if said conditional synchronization declaration is reset.