Method and apparatus for enhanced forward error correction in network

Abstract

A method and apparatus for performing error correction. A stream of data is encoded using concatenated error correcting codes. The encoded data is communicated over a transmission system. The encoded data is decoded using the codes.

What is claimed is:  
     
         1 . A method of performing error correction of transmitted information comprising: 
 encoding a stream of data using concatenated reed-solomon and turbo-code error correcting codes;    communicating said encoded data over a transmission system; and decoding said encoded data using said reed-solomon and said turbo-code error correcting codes.    
     
     
         2 . A method according to  claim 1 , wherein said transmission system is a long-haul transmission system.  
     
     
         3 . A method according to  claim 1 , wherein said long haul transmission system communicates said encoded data at least 600 kilometers.  
     
     
         4 . A method according to  claim 1 , wherein said encoding comprises: 
 packing said stream of data into a frame of first blocks;    generating said reed-solomon code for each of said first blocks;    appending said reed-solomon code to said first blocks to create a second frame of second blocks;    packing said second frame of second blocks into a third frame of third blocks; and    generating said turbo-code using said third blocks to create a fourth frame.    
     
     
         5 . A method according to  claim 4 , wherein a length of said second frame matches a length of said third frame.  
     
     
         6 . A method according to  claim 4 , wherein a length of said second frame is less than a length of said third frame.  
     
     
         7 . A method according to  claim 6 , further comprising padding said third frame with padding symbols until said length of said third frame matches said length of said second frame.  
     
     
         8 . A method according to  claim 4 , wherein said packing said second frame of second blocks into a third frame of third blocks comprises interleaving said second blocks into said third blocks.  
     
     
         9 . A method according to  claim 8 , wherein said interleaving comprises bit interleaving.  
     
     
         10 . A method according to  claim 8 , wherein said interleaving comprises byte interleaving.  
     
     
         11 . A method according to  claim 8 , wherein said third frame has a number 1-N of third blocks, with N matching an interleave depth for said encoding.  
     
     
         12 . A method of  claim 11 , wherein N is at most 64.  
     
     
         13 . A method of  claim 11 , wherein N is 16.  
     
     
         14 . A method according to  claim 1 , wherein said reed-solomon error correcting code is (255/247) code and said turbo-code is a (64,57) TPC code.  
     
     
         15 . A method according to  claim 1 , wherein said turbo-code is one of a group comprising turbo convolutional codes and turbo product codes.  
     
     
         16 . A method according to  claim 4 , wherein said decoding comprises: 
 recovering said turbo-code and said third blocks from said fourth frame;    correcting errors for said third blocks using said turbo code; unpacking said second blocks from said third blocks;    recovering said reed-solomon code and said first blocks from said second blocks; and    correcting errors for said first blocks using said reed-solomon code.    
     
     
         17 . A machine-readable medium whose contents cause a computer system to perform error correction comprising: 
 encoding a stream of data using concatenated reed-solomon and turbo-code error correcting codes;    communicating said encoded data over a transmission system; and    decoding said encoded data using said reed-solomon and turbo-code error correcting codes.    
     
     
         18 . A machine-readable medium according to  claim 17 , wherein said transmission system is a long-haul transmission system.  
     
     
         19 . A machine-readable medium according to  claim 17 , wherein said long haul transmission system communicates said encoded data at least 600 kilometers.  
     
     
         20 . A machine-readable medium according to  claim 17 , wherein said encoding comprises: 
 packing said stream of data into a frame of first blocks;    generating said reed-solomon code for each of said first blocks;    appending said reed-solomon code to said first blocks to create a second frame of second blocks;    packing said second frame of second blocks into a third frame of third blocks; and    generating said turbo-code using said third blocks to create a fourth frame.    
     
     
         21 . A machine-readable medium according to  claim 20 , wherein a length of said second frame matches a length of said third frame.  
     
     
         22 . A machine-readable medium according to  claim 20 , wherein a length of said second frame is less than a length of said third frame.  
     
     
         23 . A machine-readable medium according to  claim 22 , said method further comprising padding said third frame with padding symbols until said length of said third frame matches said length of said second frame.  
     
     
         24 . A machine-readable medium according to  claim 20 , wherein said packing said second frame of second blocks into a third frame of third blocks comprises interleaving said second blocks into said third blocks.  
     
     
         25 . A machine-readable medium according to  claim 24 , wherein said interleaving comprises bit interleaving.  
     
     
         26 . A machine-readable medium according to  claim 24 , wherein said interleaving comprises byte interleaving.  
     
     
         27 . A machine-readable medium according to  claim 24 , wherein said third frame has a number 1-N of third blocks, with N matching an interleave depth for said encoding.  
     
     
         28 . A machine-readable medium of  claim 27 , wherein N is at most 64.  
     
     
         29 . A machine-readable medium of  claim 27 , wherein N is 16.  
     
     
         30 . A machine-readable medium according to  claim 17 , wherein said reed-solomon error correcting code is (255/247) code and said turbo-code is a (64,57) TPC code.  
     
     
         31 . A machine-readable medium according to  claim 17 , wherein said turbo-code is one of a group comprising turbo convolutional codes and turbo product codes.  
     
     
         32 . A machine-readable medium according to  claim 20 , wherein said decoding comprises: 
 recovering said turbo-code and said third blocks from said fourth frame;    correcting errors for said third blocks using said turbo code;    unpacking said second blocks from said third blocks;    recovering said reed-solomon code and said first blocks from said second blocks; and    correcting errors for said first blocks using said reed-solomon code.    
     
     
         33 . An apparatus for performing error correction, comprising: 
 a forward error correction encoder configured to encode a stream of data using concatenated reed-solomon and turbo-code error correcting codes; and    a transceiver coupled to said encoder to communicate said encoded stream of data over a transmission system.    
     
     
         34 . An apparatus according to  claim 33 , wherein said transmission system is a long-haul transmission system.  
     
     
         35 . An apparatus according to  claim 33 , wherein said encoder comprises: 
 a first level encoder configured to encode said stream of data using said reed-solomon code;    an interleaver configured to interleave said first level encoded stream of data; and    a second level encoder configured to encode said interleaved stream of data using said turbo-code.    
     
     
         36 . An apparatus according to  claim 33 , wherein said reed-solomon error correcting code is (255/247) code and said turbo-code is a (64,57) TPC code.  
     
     
         37 . An apparatus according to  claim 33 , wherein said turbo-code is one of a group comprising turbo convolutional codes and turbo product codes.  
     
     
         38 . An apparatus for performing error correction, comprising: 
 a transceiver configured to receive an encoded stream of data from a transmission system, said encoded stream of data being encoded using concatenated reed-solomon and turbo-code error correcting codes; and    a forward error correction decoder configured to decode said encoded stream of data using said reed-solomon and turbo-code error correcting codes.    
     
     
         39 . An apparatus according to  claim 38 , wherein said transmission system is a long-haul transmission system.  
     
     
         40 . An apparatus according to  claim 38 , wherein said decoder comprises: 
 a first level decoder configured to decode said encoded stream of data using said turbo-code;    a deinterleaver configured to deinterleave said first level decoded stream of data; and    a second level decoder configured to decode said deinterleaved stream of data using said reed-solomon code.    
     
     
         41 . An apparatus according to  claim 38 , wherein said reed-solomon error correcting code is (255/247) code and said turbo-code is a (64,57) TPC code.  
     
     
         42 . An apparatus according to  claim 38 , wherein said turbo-code is one of a group comprising turbo convolutional codes and turbo product codes.  
     
     
         43 . A system for performing error correction, comprising: 
 a forward error correction encoder configured to encode a data stream using concatenated reed-solomon and turbo-code error correcting codes;    a long-haul communication network configured to communicate said encoded stream over a distance of at least 600 kilometers; and    a forward error correction decoder configured to decode said encoded data stream using said concatenated reed-solomon and turbo-code error correcting codes.