Apparatus and method for decoding maximum a posteriori
AssigneeElectronics and Telecommunications Research Institute
InventorsYong Ho LEE, Deock Gil OH
Life of this patent
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Abstract
A maximum a posteriori (MAP) decoding apparatus and method are provided, which select a path having a maximum value without calculating all path metrics by generating metric difference vectors based on generated tables, calculating metrics of a path formed through a combination of a state and a branch each having a maximum metric, and calculating an index and a metric of a current state to which a calculation value is to be applied based on a result of comparing a state metric difference vector and a branch metric difference vector.
Claims19
A maximum a posteriori (MAP) decoding apparatus comprising:
- a table generation unit to generate a state table and a branch table;
- a metric difference vector generation unit to generate a state metric difference vector based on state table and generate a branch metric difference vector based on the branch table;
- a first calculation unit to calculate a metric of a path formed through a combination of a state and a branch each having a maximum metric;
- a comparison unit to compare the state metric difference vector with the branch metric difference vector;
- a second calculation unit to calculate an index value and a metric of a current state to which a calculation value is to be applied through an increase of an index value of the branch metric difference vector according to a result of the comparison;
- and
- a third calculation unit to calculate the index value and the metric of the current state to which a calculation value is to be applied through an increase of an index value of the state metric difference vector according to a result of the comparison.
A maximum a posteriori (MAP) decoding method comprising:
- generating a state table and a branch table;
- generating a state metric difference vector based on state table;
- generating a branch metric difference vector based on the branch table;
- calculating a metric of a path formed through a combination of a state and a branch each having a maximum metric;
- comparing the state metric difference vector with the branch metric difference vector;
- calculating an index value and a metric of a current state to which a calculation value is to be applied through an increase of an index value of the branch metric difference vector according to a result of the comparison;
- and
- calculating the index value and the metric of the current state to which a calculation value is to be applied through an increase of an index value of the state metric difference vector according to a result of the comparison.
Dependencies are inferred from the claim text.