Transmission station and receiving station that switch between otfs modulation and ofdm modulation

A transmission station that performs wireless communication with a receiving station at a predetermined carrier frequency, comprising:

• an orthogonal frequency division multiplexing unit configured to perform orthogonal frequency division multiplexing on a symbol sequence;
• a orthogonal time frequency space multiplexing unit configured to perform orthogonal time frequency space multiplexing on a symbol sequence;
• a switching unit configured to switch between the orthogonal frequency division multiplexing unit and the orthogonal time frequency space multiplexing unit to input a symbol sequence obtained by mapping a bitstream, to only one of the orthogonal frequency division multiplexing unit and the orthogonal time frequency space multiplexing unit;
• a Doppler frequency estimation unit configured to receive a reference signal from the receiving station, and estimating a Doppler frequency based on displacement in terms of an amplitude and phase in the reference signal;
• a switching control unit configured to control the switching unit based on the Doppler frequency;
• and
• a switching notification unit configured to transmit a switching notification that is a control signal to the receiving station, when the switching unit is controlled.

A receiving station that performs wireless communication with a transmission station at a predetermined carrier frequency, comprising:

• an orthogonal frequency division multiplexing unit configured to perform orthogonal frequency division multiplexing on a symbol sequence;
• an orthogonal time frequency space multiplexing unit configured to perform orthogonal time frequency space multiplexing on a symbol sequence;
• a switching unit configured to switch between the orthogonal frequency division multiplexing unit and the orthogonal time frequency space multiplexing unit to input a symbol sequence obtained by mapping a bitstream, to only one of the orthogonal frequency division multiplexing unit and the orthogonal time frequency space multiplexing unit;
• a velocity obtaining unit configured to obtain a relative velocity between the receiving station and the transmission station;
• a switching control unit configured to control the switching unit based on a velocity;
• and
• a switching notification unit configured to transmit a switching notification that is a control signal to the transmission station, when the switching unit is controlled.

A receiving station that performs wireless communication with a transmission station at a predetermined carrier frequency, comprising:

• an orthogonal frequency division multiplexing unit configured to perform orthogonal frequency division multiplexing on a symbol sequence;
• an orthogonal time frequency space multiplexing unit configured to perform orthogonal time frequency space multiplexing on a symbol sequence;
• a switching unit configured to switch between the orthogonal frequency division multiplexing unit and the orthogonal time frequency space multiplexing unit to input a symbol sequence obtained by mapping a bitstream, to only one of the orthogonal frequency division multiplexing unit and the orthogonal time frequency space multiplexing unit;
• a Doppler frequency estimation unit configured to receive a reference signal from the transmission station, and estimating a Doppler frequency based on displacement in terms of an amplitude and phase in the reference signal;
• a switching control unit configured to control the switching unit based on the Doppler frequency;
• and
• a switching notification unit configured to transmit a switching notification that is a control signal to the transmission station, when the switching unit is controlled.