A decoder for a wireless communication device comprising a calculator for calculating the modulo of a linear approximation of a MAX* function; and a selector for selecting a MAX* output value from the group a(n)mod F, b(n)mod F, and the calculated modulo based upon a determination as to whether a predetermined threshold value for |a(n)-b(n)| has been met, where a(n) is a first state metric, b(n) is a second state metric, C is the predetermined threshold value and F is a value greater than |a(n)-b(n)|.