Patent ID: 7917834

Claim:
A method of computing a log likelihood ratio (LLR) being executed on an apparatus for computing the LLR, the method comprising: (a) calculating alpha values, beta values and gamma values of at least two time sections; (b) calculating transition probabilities in the at least two time sections using the alpha values, beta values and gamma values; (c) performing a comparison operation between some of the transition probabilities to determine a high value, selecting one of the other transition probabilities according to the determined high value, comparing the determined high value with the selected value to select a higher value, and thereby obtaining the highest of the transition probabilities; and (d) determining an operation to apply according to the highest transition probability and calculating an LLR, wherein (a) and (b) are performed for values (0, 0), (0, 1), (1, 0) and (1, 1) in two time sections, and wherein (c) comprises: (c1) comparing a transition probability to (0, 0) with a transition probability to (0, 1) and selecting the higher value; (c2) selecting a transition probability to (1, 0) when the transition probability to (0, 0) is higher than the transition probability to (0, 1), and selecting a transition probability to (1, 1) when the transition probability to (0, 1) is higher than the transition probability to (0, 0); and (c3) selecting the higher of the value selected in (c1) and the value selected in (c2) as the highest transition probability.