STATE METRIC COMPUTATION APPARATUS FOR TURBO DECODING

摘要

PURPOSE: A state metric calculation device for a turbo decoder is provided to efficiently reduce an operation delay time by reducing hardware complexity in comparison with an improved Max-Log-Map method. CONSTITUTION: A first adding unit(301,302) outputs each sum of two pairs of previous state metrics and a branch metric to the sum of a first metric sum and a second metric sum. A second adding unit(311,312,313) outputs first and second output values by adding the first metric sum and the second metric sum of the first adding unit to a constant value. A second adding unit outputs the average of the first and second metric sums to a third output value. A minimum value operating unit selectively outputs the minimum among the first to third output values of the second adding unit.