Transmission method, transmission device, reception method, and reception device
Provided is a transmission method that improves data reception quality in radio transmission using a single-carrier scheme and/or a multi-carrier scheme. The transmission method includes: generating a plurality of first modulated signals s 1 ( i ) and second modulated signals s 2 ( i ) from transmission data, the plurality of first modulated signals s 1 ( i ) being signals generated using a QPSK modulation scheme, and the plurality of second modulated signals s 2 ( i ) being signals generated using 16QAM modulation; generating, from the plurality of first modulated signals s 1 ( i ) and the plurality of second modulated signals s 2 ( i ), a plurality of first signal-processed signals z 1 ( i ) and a plurality of second signal-processed signals z 2 ( i ) which satisfy a predetermined equation; and transmitting the plurality of first signal-processed signals z 1 ( i ) and the plurality of second signal-processed signals z 2 ( i ) using a plurality of antennas. A first signal-processed signal and a second signal-processed signal having identical symbol numbers are simultaneously transmitted at the same frequency.
1. A transmission method, comprising:
modulating quadrature phase shift keying (QPSK) points s 1 ( i ) by using bits of a first stream and 16-quadrature amplitude modulation (QAM) points s 2 ( i ) by using bits of a second stream, where i is an integer greater than or equal to 0;
converting the QPSK points s 1 ( i ) and the 16-QAM points s 2 ( i ) to first converted points z 1 ( i ) and second converted points z 2 ( i ), the first converted points z 1 ( i ) and the second converted points z 2 ( i ) satisfying Equation (1),
(
z
1
(
i
)
z
2
(
i
)
)
=
(
1
0
0
y
(
i
)
)
1
2
(
1
1
1
-
1
)
(
2
/
3
0
0
4
/
3
)
(
s
1
(
i
)
s
2
(
i
)
)
Equation
(
1
)
where y(i) varies according to index i; and
transmitting a first orthogonal frequency division multiplexing (OFDM) signal including the first converted points z 1 ( i ) and a second OFDM signal including the second converted points z 2 ( i ) using a plurality of antennas.
2. A transmission device, comprising:
a mapper that, in operation, modulates quadrature phase shift keying (QPSK) points s 1 ( i ) by using bits of a first stream and 16-quadrature amplitude modulation (QAM) points s 2 ( i ) by using bits of a second stream, where i is an integer greater than or equal to 0;
a signal processor that, in operation, converts the QPSK points s 1 ( i ) and the 16-QAM points s 2 ( i ) to first converted points z 1 ( i ) and second converted points z 2 ( i ), the first converted points z 1 ( i ) and the second converted points z 2 ( i ) satisfying Equation (1),
(
z
1
(
i
)
z
2
(
i
)
)
=
(
1
0
0
y
(
i
)
)
1
2
(
1
1
1
-
1
)
(
2
/
3
0
0
4
/
3
)
(
s
1
(
i
)
s
2
(
i
)
)
Equation
(
1
)
where y(i) varies according to index i; and
a transmitter that, in operation, transmits a first orthogonal frequency division multiplexing (OFDM) signal including the first converted points z 1 ( i ) and a second OFDM signal including the second converted points z 2 ( i ) using a plurality of antennas.
3. A reception method, comprising:
obtaining reception signals by receiving one or more orthogonal frequency division multiplexing (OFDM) signals including first converted signals z 1 ( i ) and second converted signals z 2 ( i ) transmitted by using a plurality of antennas, where i is an integer greater than or equal to 0,
wherein the first converted signals z 1 ( i ) and the second converted signals z 2 ( i ) are generated by converting quadrature phase shift keying (QPSK) points s 1 ( i ) and 16-quadrature amplitude modulation (QAM) points s 2 ( i ), the QPSK points s 1 ( i ) are modulated by using bits of a first stream and the 16-QAM points s 2 ( i ) are modulated by using bits of a second stream, the first converted signals z 1 ( i ) and the second converted signals z 2 ( i ) satisfy Equation (1),
(
z
1
(
i
)
z
2
(
i
)
)
=
(
1
0
0
y
(
i
)
)
1
2
(
1
1
1
-
1
)
(
2
/
3
0
0
4
/
3
)
(
s
1
(
i
)
s
2
(
i
)
)
Equation
(
1
)
where y(i) varies according to index i; and
demodulating the reception signals according to the conversion applied to the QPSK points s 1 ( i ) and the 16-QAM points s 2 ( i ).
4. A reception device, comprising:
a receiver that, in operation, obtains reception signals by receiving one or more orthogonal frequency division multiplexing (OFDM) signals including first converted signals z 1 ( i ) and second converted signals z 2 ( i ) transmitted by using a plurality of antennas, where i is an integer greater than or equal to 0,
wherein the first converted signals z 1 ( i ) and the second converted signals z 2 ( i ) are generated by converting quadrature phase shift keying (QPSK) points s 1 ( i ) and 16-quadrature amplitude modulation (QAM) points s 2 ( i ), the QPSK points s 1 ( i ) are modulated by using bits of a first stream and the 16-QAM points s 2 ( i ) are modulated by using bits of a second stream, the first converted signals z 1 ( i ) and the second converted signals z 2 ( i ) satisfy Equation (1),
(
z
1
(
i
)
z
2
(
i
)
)
=
(
1
0
0
y
(
i
)
)
1
2
(
1
1
1
-
1
)
(
2
/
3
0
0
4
/
3
)
(
s
1
(
i
)
s
2
(
i
)
)
Equation
(
1
)
where y(i) varies according to index i; and
a demodulator that, in operation, demodulates the reception signals according to conversion applied to the QPSK points s 1 ( i ) and the 16-QAM points s 2 ( i ).
5. The transmission method of claim 1 , further comprising:
generating, with a first radio unit, a first transmission signal based on the first OFDM signal; and
generating, with a second radio unit, a second transmission signal based on the second ODFM signal.
6. The transmission method of claim 5 , further comprising:
outputting, from a first antenna unit, first radio waves based on the first transmission signal; and
outputting, from a second antenna unit, second radio waves based on the second transmission signal.
7. The transmission method of claim 1 , further comprising:
converting the QPSK points s 1 ( i ) and the 16-QAM points s 2 ( i ) to first converted points z 1 ( i ) and second converted points z 2 ( i ) based on a control signal.
8. The transmission device of claim 2 , wherein the transmitter comprises:
a first radio unit to generate a first transmission signal based on the first OFDM signal; and
a second radio unit to generate a second transmission signal based on the second ODFM signal.
9. The transmission device of claim 8 , wherein the transmitter further comprises:
a first antenna unit to output first radio waves based on the first transmission signal; and
a second antenna unit to output second radio waves based on the second transmission signal.
10. The transmission device of claim 2 , wherein the signal processor is further to:
convert the QPSK points s 1 ( i ) and the 16-QAM points s 2 ( i ) to first converted points z 1 ( i ) and second converted points z 2 ( i ) based on a control signal.
11. The reception method of claim 3 , further comprising:
generating a first channel estimate corresponding to the first converted signals;
generating a second channel estimate corresponding to the second converted signals; and
demodulating the reception signals based on the first and second channel estimates.
12. The reception device of claim 4 , further comprising:
a first channel estimation unit to generate a first channel estimate corresponding to the first converted signals; and
a second channel estimation unit to generate a second channel estimate corresponding to the second converted signals,
wherein the demodulator is to demodulate the reception signals based on the first and second channel estimates.
13. One or more non-transitory, computer-readable media having instructions that, when executed by processing circuitry, cause a device to:
modulate quadrature phase shift keying (QPSK) points s 1 ( i ) by using bits of a first stream and 16-quadrature amplitude modulation (QAM) points s 2 ( i ) by using bits of a second stream, where i is an integer greater than or equal to 0;
convert the QPSK points s 1 ( i ) and the 16-QAM points s 2 ( i ) to first converted points z 1 ( i ) and second converted points z 2 ( i ), the first converted points z 1 ( i ) and the second converted points z 2 ( i ) satisfying Equation (1),
(
z
1
(
i
)
z
2
(
i
)
)
=
(
1
0
0
y
(
i
)
)
1
2
(
1
1
1
-
1
)
(
2
/
3
0
0
4
/
3
)
(
s
1
(
i
)
s
2
(
i
)
)
Equation
(
1
)
where y(i) varies according to index i; and
transmit a first orthogonal frequency division multiplexing (OFDM) signal including the first converted points z 1 ( i ) and a second OFDM signal including the second converted points z 2 ( i ) using a plurality of antennas.
14. The one or more non-transitory, computer-readable media of claim 13 , wherein the instructions, when executed, further cause the device to:
generate a first transmission signal based on the first OFDM signal; and
generate a second transmission signal based on the second ODFM signal.
15. The one or more non-transitory, computer-readable media of claim 13 , wherein the instructions, when executed, further cause the device to:
generate a control signal; and
convert the QPSK points s 1 ( i ) and the 16-QAM points s 2 ( i ) to first converted points z 1 ( i ) and second converted points z 2 ( i ) based on the control signal.
16. One or more non-transitory, computer-readable media having instructions that, when executed by processing circuitry, cause a device to:
obtain reception signals by receiving one or more orthogonal frequency division multiplexing (OFDM) signals including first converted signals z 1 ( i ) and second converted signals z 2 ( i ) transmitted by using a plurality of antennas, where i is an integer greater than or equal to 0,
wherein the first converted signals z 1 ( i ) and the second converted signals z 2 ( i ) are generated by converting quadrature phase shift keying (QPSK) points s 1 ( i ) and 16-quadrature amplitude modulation (QAM) points s 2 ( i ), the QPSK points s 1 ( i ) are modulated by using bits of a first stream and the 16-QAM points s 2 ( i ) are modulated by using bits of a second stream, the first converted signals z 1 ( i ) and the second converted signals z 2 ( i ) satisfy Equation (1),
(
z
1
(
i
)
z
2
(
i
)
)
=
(
1
0
0
y
(
i
)
)
1
2
(
1
1
1
-
1
)
(
2
/
3
0
0
4
/
3
)
(
s
1
(
i
)
s
2
(
i
)
)
Equation
(
1
)
where y(i) varies according to index i; and
demodulate the reception signals according to conversion applied to the QPSK points s 1 ( i ) and the 16-QAM points s 2 ( i ).
17. The one or more non-transitory, computer-readable media of claim 16 , wherein the instructions, when executed, further cause the device to:
demodulate the reception signals based on a control signal.
18. The one or more non-transitory, computer-readable media of claim 16 , wherein the instructions, when executed, further cause the device to:
generate a first channel estimate corresponding to the first converted signals;
generate a second channel estimate corresponding to the second converted signals; and
demodulate the reception signals based on the first and second channel estimates.