Signal generating method and signal generating device
A transmission method for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. Each signal has been modulated according to a different modulation scheme. The transmission method applies precoding on both signals using a fixed precoding matrix, applies different power change to each signal, and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.
1. A transmission apparatus comprising:
signal processing circuitry which, in operation, performs precoding and phase change on a modulated symbol sequence s 1 and a modulated symbol sequence s 2 according to a control signal; and
transmission circuitry which, in operation, transmits two signals including the control signal and the modulated symbol sequences s 1 and s 2 applied the precoding and the phase change, from a plurality of antennas, wherein
the modulated symbol sequences s 1 and s 2 applied the precoding and the phase change are demodulated by a reception apparatus,
the control signal includes a first field and a second field,
the first field indicates a precoding matrix selected either (i) as a first precoding matrix used for the precoding, a matrix selected from among a plurality of different matrices based on a combination of respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 or (ii) as a second precoding matrix used for the precoding, a matrix obtained by multiplying an identity matrix by a coefficient other than zero,
the second field indicates the combination of the respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 , and
the phase change is performed on the modulated symbol sequences s 1 and s 2 using a phase that changes for each symbol.
2. A reception apparatus comprising:
reception circuitry which, in operation, receives one or more signals including a control signal and a modulated symbol sequence s 1 and a modulated symbol sequence s 2 applied precoding and phase change; and
demodulation circuitry which, in operation, demodulates the modulated symbol sequences s 1 and s 2 based on a combination of respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 , the combination being indicated by the control signal, wherein
the one or more signals are generated by a transmission apparatus performing:
the precoding and the phase change on the modulated symbol sequences s 1 and s 2 according to the control signal; and
transmission of two signals including the control signal and the modulated symbol sequences s 1 and s 2 applied the precoding and the phase change, from a plurality of antennas, wherein
the control signal includes a first field and a second field,
the first field indicates a precoding matrix selected either (i) as a first precoding matrix used for the precoding, a matrix selected from among a plurality of different matrices based on the combination of the respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 or (ii) as a second precoding matrix used for the precoding, a matrix obtained by multiplying an identity matrix by a coefficient other than zero,
the second field indicates the combination of the respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 , and
the phase change is performed on the modulated symbol sequences s 1 and s 2 using a phase that changes for each symbol.
3. A transmission method comprising:
performing precoding and phase change on a modulated symbol sequence s 1 and a modulated symbol sequence s 2 according to a control signal; and
transmitting two signals including the control signal and the modulated symbol sequences s 1 and s 2 applied the precoding and the phase change, from a plurality of antennas, wherein
the modulated symbol sequences s 1 and s 2 applied the precoding and the phase change are demodulated by a reception apparatus,
the control signal includes a first field and a second field,
the first field indicates a precoding matrix selected either (i) as a first precoding matrix used for the precoding, a matrix selected from among a plurality of different matrices based on a combination of respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 or (ii) as a second precoding matrix used for the precoding, a matrix obtained by multiplying an identity matrix by a coefficient other than zero,
the second field indicates the combination of the respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 , and
the phase change is performed on the modulated symbol sequences s 1 and s 2 using a phase that changes for each symbol.
4. A reception method comprising:
receiving one or more signals including a control signal and a modulated symbol sequence s 1 and a modulated symbol sequence s 2 applied precoding and phase change; and
demodulating the modulated symbol sequences s 1 and s 2 based on a combination of respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 , the combination being indicated by the control signal, wherein
the one or more signals are generated by a transmission apparatus performing:
the precoding and the phase change on the modulated symbol sequences s 1 and s 2 according to the control signal; and
transmission of two signals including the control signal and the modulated symbol sequences s 1 and s 2 applied the precoding and the phase change, from a plurality of antennas, wherein
the control signal includes a first field and a second field,
the first field indicates a precoding matrix selected either (i) as a first precoding matrix used for the precoding, a matrix selected from among a plurality of different matrices based on the combination of the respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 or (ii) as a second precoding matrix used for the precoding, a matrix obtained by multiplying an identity matrix by a coefficient other than zero,
the second field indicates the combination of the respective modulation schemes applied to the modulated symbol sequences s 1 and s 2 , and
the phase change is performed on the modulated symbol sequences s 1 and s 2 using a phase that changes for each symbol.