Radio communication apparatus, and radio communication method

A radio communication apparatus comprising:

• a receiver, which, in operation, receives control information associated with a number of bits;
• and
• circuitry, which, in operation:
• generates a bit sequence by forcing setting each place of the number of bits determined from the control information of a plurality of bits to a 1, the plurality of bits forming a modulation symbol in the bit sequence;
• and
• modulates the bit sequence by mapping the plurality of bits on a single modulation mapper, the single modulation mapper having first signal points,
• wherein said circuitry, in operation, forcibly sets each place of the number of bits to the 1 in a way that the plurality of bits are mapped to one of second signal points, which are a part of the first signal points, such that said modulation symbol is detected by positive or negative decision only with respect to at least one of an I-axis and a Q-axis in the single modulation mapper.

A radio communication method comprising:

• receiving control information associated with a number of bits;
• generating a bit sequence by forcibly setting each place of the number of bits determined from the control information of a plurality of bits to a 1, the plurality of bits forming a modulation symbol in the bit sequence;
• and
• modulating the bit sequence by mapping the plurality of bits on a single modulation mapper, the single modulation mapper having first signal points,
• wherein each place of the number of bits is forcibly set to the 1 in a way that the plurality of bits are mapped to one of second signal points, which are a part of the first signal points, a distance between the second signal points being equivalent to a largest of distances existing among the first signal points in an I-Q plane of the single modulation mapper.

A radio communication method comprising:

• receiving control information associated with a number of bits;
• generating a bit sequence by forcibly setting each place of the number of bits determined from the control information of a plurality of bits to a 1, the plurality of bits forming a modulation symbol in the bit sequence;
• and
• modulating the bit sequence by mapping the plurality of bits on a single modulation mapper, the single modulation mapper having first signal points,
• wherein each place of the number of bits is forcibly set to the 1 in a way that the plurality of bits are mapped to one of second signal points, which are a part of the first signal points, such that said modulation symbol is detected by positive or negative decision only with respect to at least one of an I-axis and a Q-axis in the single modulation mapper.