Transmission device and transmission method

A transmission apparatus, comprising:

• memory;
• and
• circuitry which, in operation, performs:
• selecting one transmission scheme from among transmission scheme candidates, the transmission scheme candidates including a first transmission scheme and a second transmission scheme,
• (i) when the first transmission scheme is selected,
• modulating a first bit sequence using Quadrature Phase Shift Keying (QPSK) to generate a single symbol sequence;
• performing a first precoding on N first symbols included in the single symbol sequence to generate N first precoded symbols, where N is an integer equal to or greater than two;
• and
• transmitting the N first precoded symbols at same time, the N first precoded symbols being mapped on N subcarriers, and
• (ii) when the second transmission scheme is selected,
• modulating a second bit sequence using QPSK to generate M symbol sequences, where M is an integer equal to or greater than two;
• performing a second precoding on M second symbols to generate 2M second precoded symbols, the M second symbols including one symbol included in each of the M symbol sequences;
• and
• transmitting the 2M second precoded symbols through 2M antennas at same time, the 2M second precoded symbols being mapped on same subcarrier.