Apparatus for processing received signal, method thereof, and method for selecting mapping rule

A method for mapping rule selecting, which is applied to an iterative decoding scheme for performing decoding by using reliability information of a received bit signal, the method comprising the steps of:

• calculating a mean bit error value, a first metric value, and a second metric value for at least one mapping rule corresponding to a specific modulation scheme;
• grouping the at least one mapping rule with reference to the mean bit error value;
• first selecting at least one mapping rule having a maximum first metric value from the mapping rules belonging to a specific group;
• and
• second selecting at least one mapping rule having a maximum second metric value from the first selected mapping rules.

A method of selecting a mapping rule, the method applied to an iterative bit-interleaved coded modulation (BICM) system, the method comprising the steps of:

• grouping an available mapping rule for a specific modulation scheme according to a selection reference;
• selecting a group according to the selection reference;
• and
• selecting a specific mapping rule among the mapping rules in the selected group.