Pre-coding method and transmitter

A transmission apparatus comprising:

• signal processing circuitry, which in operation,
• modulates a first data sequence to a first modulation symbol sequence s1(t) and a second data sequence to a second modulation symbol sequence s2(t);
• selects whether to perform a precoding process,
• generates a first transmission symbol sequence z1(t) and a second transmission symbol sequence z2(t) by using a first modulation symbol sequence s1(t) and a second modulation symbol sequence s2(t), wherein t is an integer no less than 0;
• and
• transmission circuitry, which in operation, transmits the first transmission symbol sequence z1(t) and the second transmission symbol sequence z2(t) from a first transmission antenna and a second transmission antenna respectively in the same frequency at the same time, wherein
• in a case where the result of the selecting indicates that the precoding process is performed,
• the first transmission symbol sequence z1(t) and the second transmission symbol sequence z2(t) are generated by performing the precoding process using N matrices F[i] on the first modulation symbol sequence s1(t) and the second modulation symbol sequence s2(t);
• and
• the N matrices F[i] have one or more matrix elements that changes according to i,
• wherein i is an integer no less than 0 and no more than N−1, i varies according to t, and N is an integer 2 or greater,
• the first transmission symbol sequence z1(t) includes the first modulation symbol sequence s1(t) to which the precoding process is not applied and the second modulation symbol sequence s2(t) to which the precoding process is not applied, and
• the second transmission symbol sequence z2(t) includes the first modulation symbol sequence s1(t) to which the precoding process is applied and the second modulation symbol sequence s2(t) to which the precoding process is applied.

A reception method comprising:

• receiving a plurality of signals transmitted from a plurality of transmission antennas in the same frequency at the same time, the plurality of signals including one or more control signals related to generation of a first transmission symbol sequence z1(t) and a second transmission symbol sequence z2(t), wherein t is an integer no less than 0;
• and
• generating a first data sequence and a second data sequence by demodulating the first transmission symbol sequence z1(t) and the second transmission symbol sequence z2(t) based on the one or more control signals, wherein
• in a case where the one or more control signals indicates that the precoding process is performed,
• the plurality of signals are transmitted based on the first transmission symbol sequence z1(t) and the second transmission symbol sequence z2(t) that are generated by performing the precoding process using N matrices F[i] on a first modulation symbol sequence s1(t) and a second modulation symbol sequence s2(t),
• the N matrices F[i] have one or more matrix elements that changes according to i, wherein i is an integer no less than 0 and no more than N−1, i varies according to t, and N is an integer 2 or greater,
• the first transmission symbol sequence z1(t) includes the first modulation symbol sequence s1(t) to which the precoding process is not applied and the second modulation symbol sequence s2(t) to which the precoding process is not applied, and
• the second transmission symbol sequence z2(t) includes the first modulation symbol sequence s1(t) to which the precoding process is applied and the second modulation symbol sequence s2(t) to which the precoding process is applied.

A reception apparatus comprising:

• reception circuitry, which in operation, receives a plurality of signals transmitted from a plurality of transmission antennas in the same frequency at the same time, the plurality of signals including one or more control signals related to generation of a first transmission symbol sequence z1(t) and a second transmission symbol sequence z2(t), wherein t is an integer no less than 0;
• signal processing circuitry, which in operation, generates a first data sequence and a second data sequence by demodulating the first transmission symbol sequence z1(t) and the second transmission symbol sequence z2(t) based on the one or more control signals, wherein
• in a case where the one or more control signals indicates that the precoding process is performed,
• the plurality of signals are transmitted based on the first transmission symbol sequence z1(t) and the second transmission symbol sequence z2(t) that are generated by performing the precoding process using N matrices F[i] on a first modulation symbol sequence s1(t) and a second modulation symbol sequence s2(t), wherein t is an integer no less than 0,
• the N matrices F[i] have one or more matrix elements that changes according to i, wherein i is an integer no less than 0 and no more than N−1, i varies according to t, and N is an integer 2 or greater,
• the first transmission symbol sequence z1(t) includes the first modulation symbol sequence s1(t) to which the precoding process is not applied and the second modulation symbol sequence s2(t) to which the precoding process is not applied, and
• the second transmission symbol sequence z2(t) includes the first modulation symbol sequence s1(t) to which the precoding process is applied and the second modulation symbol sequence s2(t) to which the precoding process is applied.