Abstract: A low density parity check (LDPC) coding unit performs LDPC coding. An interleaving unit interleaves the LDPC-coded data, based on an array according to the number of bits that constitute a modulated symbol. A per-area division rearrangement unit divides to classify the interleaved data into a plurality of areas in a manner such that each area is formed by contiguous data and also outputs data, according to the number of bits that constitute the modulated symbol, by successively changing the areas. A symbol mapping unit generates the modulated symbol based on the data fed from the per-area division rearrangement unit.

Abstract: A frame data storage unit inputs LDPC encoded data via a communication path. An estimation unit estimates, based on the inputted data, a situation of the communication path. A selection unit select, in accordance with the estimated situation of the communication path, one of a plurality of normalization constants that have been specified in advance and are to be used in updating an exterior value ratio based on a priori value ratio in check node processing according to a min-sum algorithm. A min-sum processing unit executes, on the inputted data, the min-sum algorithm by using the selected normalization constant.