Transmission device, reception device, transmission method, and reception method

A reception device comprising:

• a receiver configured to receive a multiplexed signal on which a first modulated symbol stream and a second modulated symbol stream are superposed at an amplitude ratio, the first modulated symbol stream being generated by mapping a first bit stream of a first data series, the second modulated symbol stream being generated by mapping a second bit stream of a second data series, the first modulated symbol stream and the second modulated symbol stream being representable on a complex plane extending in a first direction and a second direction perpendicular to the first direction;
• and
• a deriver configured to derive at least one of the first data series or the second data series from the multiplexed signal, wherein
• the receiver receives the multiplexed signal on which the second modulated symbol stream is converted in accordance with the first modulated symbol stream only in the first direction on the complex plane.

A transmission method comprising:

• mapping a first bit stream of a first data series to generate a first modulated symbol stream;
• mapping a second bit stream of a second data series to generate a second modulated symbol stream, the first modulated symbol stream and the second modulated symbol stream being representable on a complex plane extending in a first direction and a second direction perpendicular to the first direction;
• converting the second modulated symbol stream in accordance with the first modulated symbol stream only in the first direction on the complex plane;
• superposing the first modulated symbol stream and the second modulated symbol stream, at an amplitude ratio, to generate a multiplexed signal after the second modulated symbol stream is converted;
• and
• transmitting the multiplexed signal.

A reception method comprising:

• receiving a multiplexed signal on which a first modulated symbol stream and a second modulated symbol stream are superposed at an amplitude ratio, the first modulated symbol stream being generated by mapping a first bit stream of a first data series, the second modulated symbol stream being generated by mapping a second bit stream of a second data series, the first modulated symbol stream and the second modulated symbol stream being representable on a complex plane extending in a first direction and a second direction perpendicular to the first direction;
• and
• deriving at least one of the first data series or the second data series from the multiplexed signal, wherein
• the second modulated symbol stream is converted in accordance with the first modulated symbol stream only in the first direction on the complex plane when the multiplexed signal is received.