Patent ID: 6760390
Filing Date: 2004-07-06
Classification: H04L

Abstract:
A method for a decoder to perform log domain maximum a posteriori (log-MAP) decoding, the method comprising the steps of:generating a code graph; processing information comprising a plurality of transformed probabilities; manipulating the information for creating forward and backward recursions on the code graph; combining the information and the forward and backward recursions for producing log-likelihood ratios on the code graph; the manipulating and combining steps comprise a log-add kernel operation of computing a logarithm of a sum of a plurality of exponentiated input arguments; and representing the log-add kernel operation as a summation of an average of a plurality of the input arguments and a correction factor; wherein the log-add kernel operation is represented by the summation of the average of the plurality of input arguments and a correction factor for a range of the plurality of input arguments, and is used by the decoder for decoding data.