Correcting output of a Max-Log-MAP algorithm using a mask

摘要

The invention relates to an arithmetic circuit to correct an approximate value computed by a Max-Log-MAP (based on Log-MAP) algorithm. The arithmetic circuit comprises a maximum value output circuit which outputs a maximum value of the Max-Log-MAP algorithm and a correction circuit which corrects the maximum value. The correction circuit includes:

i) a mask value generator which calculates a mask value based on a path metric value composed of a plurality of bits,

ii) a mask processor which performs mask processing on the path metric value based on the mask value; and

iii) a logic circuit calculating a logical OR of the maximum value and an output of the mask processor. The invention can also be carried out using the minimum value of the Max-Log-MAP algorithm, which changes the logic circuit so that it calculates a logical AND of the minimum value and the output of the mask processor.