Patent ID: 8650459

Claim:
A method for determining a log-likelihood ratio (LLR) for a bit bi in a message being generated, comprising: obtaining: (1) a codebook which includes a plurality of messages and a plurality of codewords and (2) a specified bit value, wherein the LLR for bit bi is based at least in part on the codebook and the specified bit value; for bit bi in the message being generated, generating a first term, including by: accessing the codebook in order to determine those messages which have a bit bi with a value of 0; selecting, from those messages determined to have a bit bi with a value of 0, a first selected message, wherein the first selected message corresponds to a first selected codeword in the codebook; and summing one or more LLRs corresponding to bits in the first selected codeword having the specified bit value; for bit bi in the message being generated, generating a second term, including by: accessing the codebook in order to determine those messages which have a bit bi with a value of 1; selecting, from those messages determined to have a bit bi with a value of 1, a second selected message, wherein the second selected message corresponds to a second selected codeword in the codebook; and summing one or more LLRs corresponding to bits in the second selected codeword having the specified bit value; and for bit bi in the message being generated, using a processor to generate the LLR based at least in part on the first term and the second term.