Patent ID: 7260762

Claim:
A method of adapting a number of test patterns in a soft-input soft-output decoder to generate a soft-output vector, comprising: finding L+a least reliable positions within a soft-input vector; constructing a set of test patterns where the set of test patterns is related to L least reliable positions; for each test pattern vector Zi in the set of test patterns, performing a hard-decision decoding on a vector (Y+Zi) wherein Y is a binary vector constructed from the soft-input vector; if the hard-decision decoder finds a valid codeword Ci associated with the vector (Y+Zi), saving the valid codeword Ci into a set S; if the hard-decision decoder is unable to find a valid codeword, constructing an augmented test pattern Zi′ using at least one of a least reliable positions, further comprising: if hard-decision decoding the augmented binary vector (Y+Zi′) finds a valid codeword Ci′ associated with the binary vector (Y+Zi′), saving the valid codeword Ci′ into the set S; and generating the soft-output vector based on the set S.