Method of identifying a correct decoding codeword

Abstract

A method of searching for candidate codewords for a telecommunications system, the method comprising receiving a sequence of constellation points, producing a received FEC vector comprised of bits from the received constellation points, comparing the received FEC vector with a plurality of candidate codewords within a Dorsch decoding process using an ordered pattern, and terminating the search when a candidate codeword from among the plurality of candidate codewords is found residing within a predetermined range of a specified distance of the received FEC vector.

1 . A method of searching for candidate codewords for a telecommunications system, the method comprising:
 receiving a sequence of constellation points;   producing a received FEC vector comprised of bits from the received constellation points;   comparing the received FEC vector with a plurality of candidate codewords within a Dorsch decoding process using an ordered pattern; and   terminating the search when a candidate codeword from among the plurality of candidate codewords is found residing within a predetermined range of a specified distance of the received FEC vector.   
     
     
         2 . The method of  claim 1 , further comprising ordering the plurality of candidate codewords according to a probability that each of the candidate codewords will occur within the predetermined range of the specified distance of the received point. 
     
     
         3 . The method of  claim 1 , further comprising sorting the received FEC vector according to a probability of reliability of each bit position of the received FEC vector. 
     
     
         4 . The method of  claim 3 , further comprising generating one or more candidate codewords among the plurality of candidate codewords by creating one or more perturbations to one or more first bits of a base codeword of a sorted received FEC vector. 
     
     
         5 . The method of  claim 3 , further comprising classifying a magnitude of each bit position as a logarithmic likelihood ratio (LLR) that is calculated as a logarithm of a probability that one received bit position has one sent value divided by a probability that the one received bit has a value opposite the one sent value. 
     
     
         6 . The method of  claim 5 , further comprising quantizing the bit positions having a highest magnitude into a fixed number of levels using a uniform integer scalar quantizer. 
     
     
         7 . A method of searching for candidate codewords for a telecommunications system, the method comprising:
 receiving one or more constellation points;   mapping the received constellation points into a received FEC vector representing a point in an N-dimensional space;   determining whether a bit position in the codeword has a positive value or a negative value;   determining whether a corresponding position element of the received FEC vector has a positive value or a negative value;   comparing the bit position value with the corresponding position element value;   re-mapping one or more position elements onto one or more planes of a hypercube surface;   calculating a squared distance between the re-mapped received FEC vector and a candidate codeword; and   terminating the search if the comparison of the values result indicates a confidence level of the one or more constellation points that is higher than a predetermined confidence threshold.   
     
     
         8 . The method of  claim 7 , further comprising mapping one or more received FEC vector elements to a codeword at a center of a region comprised of points that are less than a fixed square distance from the codeword. 
     
     
         9 . A method of searching for candidate codewords for a telecommunications system, the method comprising:
 receiving a plurality of constellation points;   producing a one or more received FEC vectors comprised of bits from the received constellation points;   decoding the one or more received FEC vectors using a plurality of Dorsch decoders;   comparing the one or more received FEC vectors with a plurality of candidate codewords within a Dorsch decoding process using an ordered pattern;   releasing a best match codeword into an output buffer; and   terminating the search when a codeword is found residing within a predetermined range of a specified distance of the one or more received FEC vectors.   
     
     
         10 . The method of  claim 9 , wherein the one or more received FEC vectors comprise a unique identifier indicating an order in which the one or more received FEC vectors is received by the plurality of Dorsch decoders. 
     
     
         11 . The method of  claim 9 , further comprising recording, by an ordering device, an order in which the one or more received FEC vectors is received by the plurality of Dorsch decoders. 
     
     
         12 . The method of  claim 9 , further comprising simultaneously decoding two or more received FEC vectors using two or more decoders of the plurality of Dorsch decoders. 
     
     
         13 . The method of  claim 9 , further comprising releasing by the output buffer to a downstream receiver, best match codewords in an order in which the codewords were received. 
     
     
         14 . A method of searching for candidate codewords for a telecommunications system, the method comprising:
 receiving one or more constellation points;   mapping the received constellation points into one or more received FEC vectors, each received FEC vector representing a point in an N-dimensional space;   decoding the one or more received FEC vectors using a plurality of Dorsch decoders;   determining whether a bit position in a candidate codeword has a positive value or a negative value;   determining whether a corresponding position element of the one or more received FEC vectors has a positive value or a negative value;   comparing the bit position value and the corresponding element position value;   re-mapping one or more position elements onto one or more planes of a hypercube surface;   calculating a squared distance between the re-mapped received FEC vector and the candidate codeword; and   terminating the search if the bit position value and the corresponding element position value indicate a confidence level of the one or more constellation points that is higher than a predetermined confidence threshold.   
     
     
         15 . The method of  claim 14 , wherein each of the one or more received FEC vectors comprises a unique identifier indicating an order in which the one or more FEC vectors is received by the plurality of Dorsch decoders. 
     
     
         16 . The method of  claim 14 , further comprising recording, by an ordering device, an order in which the one or more FEC vectors is received by the plurality of Dorsch decoders. 
     
     
         17 . The method of  claim 14 , further comprising simultaneously decoding two or more received FEC vectors using two or more decoders of the plurality of Dorsch decoders. 
     
     
         18 . The method of  claim 14 , further comprising releasing by the output buffer to a downstream receiver, best match codewords in an order in which the codewords were received.