Signal generation method and signal generation device
A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.
1. A transmitting apparatus comprising:
signal processing circuitry configured to:
generate a first frame and a second frame; and
apply a phase change to the second frame to generate a second phase-changed frame, the phase change not being applied to the first frame; and
a transmitter configured to transmit the first frame and the second phase-changed frame from a first antenna and a second antenna, respectively, wherein in the phase change:
a first phase change value is applied to a first symbol in the second frame;
a second phase change value is applied to a second symbol adjacent to the first symbol in a time direction in the second frame;
a third phase change value is applied to a third symbol adjacent to the first symbol in the second frame;
the second phase change value is different from the first phase change value; and
the third phase change value is different from the first phase change value.
2. The transmitting apparatus according to claim 1 , wherein
a phase change pattern of the phase change is determined based at least in part on a combination of a coding rate and a modulation scheme, and
at least two different phase change patterns are provided for a same combination of the coding rate and the modulation scheme.
3. The transmitting apparatus according to claim 1 , wherein
the second frame includes a pilot symbol and a data symbol, and
the phase change is not applied to the pilot symbol but applied to the data symbol.
4. A receiving apparatus comprising,
a receiver configured to receive a first frame and a second phase-changed frame from a first antenna and a second antenna, respectively; and
signal processing circuitry configured to decode the first frame and the second phase-changed frame, wherein
the first frame and the second phase-changed frame are generated by a coding process, and
the coding process comprises:
generating the first frame and a second frame; and
applying a phase change to the second frame to generate the second phase-changed frame, the phase change not being applied to the first frame; and
in the phase change:
a first phase change value is applied to a first symbol in the second frame;
a second phase change value is applied to a second symbol adjacent to the first symbol in a time direction in the second frame;
a third phase change value is applied to a third symbol adjacent to the first symbol in a frequency direction in the second frame;
the second phase change value is different from the first phase change value; and
the third phase change value is different from the first phase change value.