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:
encoding circuitry which, in operation, generates two codeword sequences;
modulation circuitry which, in operation, generates a modulated symbol sequence s 1 and a modulated symbol sequence s 2 from the two codeword sequences according to a control signal;
signal processing circuitry which, in operation, performs precoding and phase change on the modulated symbol sequences s 1 and s 2 according to the 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 whether (i) a first precoding matrix or (ii) a second precoding matrix is used to perform the precoding, the first precoding matrix being selected from among a plurality of different matrices based on modulation schemes applied to the modulated symbol sequences s 1 and s 2 , the second precoding matrix corresponding to an identity matrix,
the second field indicates the modulation schemes applied to the modulated symbol sequences s 1 and s 2 , and the phase change is performed on the modulated symbol sequences sl 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;
and decoding circuitry which, in operation, generates two codeword sequences from the modulated symbol sequences s 1 and s 2 , wherein the one or more signals are generated by a transmission apparatus performing:
generation of the two codeword sequences;
generation of the modulated symbol sequences sl and s 2 from the two codeword sequences according to the control signal;
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 whether (i) a first precoding matrix or (ii) a second matrix is used to perform the precoding, the first precoding matrix being selected from among a plurality of different matrices based on modulation schemes applied to the modulated symbol sequences s 1 and s 2 , the second precoding matrix corresponding to an identity matrix,
the second field indicates the 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:
generating two codeword sequences;
generating a modulated symbol sequence s 1 and a modulated symbol sequence s 2 from the two codeword sequences according to a control signal;
performing precoding and phase change on the modulated symbol sequences s 1 and s 2 according to the 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 whether (i) a first precoding matrix or (ii) a second precoding matrix is used to perform the precoding, the first precoding matrix being selected from among a plurality of different matrices based on modulation schemes applied to the modulated symbol sequences s 1 and s 2 , the second precoding matrix corresponding to an identity matrix,
the second field indicates the 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;
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; and
generating two codeword sequences from the modulated symbol sequences s 1 and s 2 , wherein
the one or more signals are generated by a transmission apparatus performing:
generation of the two codeword sequences;
generation of the modulated symbol sequences s 1 and s 2 from the two codeword sequences according to the control signal;
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 whether (i) a first precoding matrix or (ii) a second precoding matrix is used to perform the precoding, the first precoding matrix being selected from among a plurality of different matrices based on modulation schemes applied to the modulated symbol sequences s 1 and s 2 , the second precoding matrix corresponding to an identity matrix,
the second field indicates the 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.