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

A transmission device, comprising:

• a mapper that, in operation, modulates quadrature phase shift keying (QPSK) points s1(i) by using bits of a first stream and 16 quadrature amplitude modulation (QAM) points s2(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 s1(i) and the 16-QAM points s2(i) to first converted points z1(i) and second converted points z2(i), the first converted points z1(i) and the second converted points z2(i) satisfying Equation (1), wherein the Equation (1) is defined as:
• (
• 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
• )
• )
• ,
• where y(i) is a function represented by ejδ(i), where δ(i) is a real value incremented by a constant value for every i, a value of y(i) periodically varies with a period of N, where N is 8;
• and
• a transmitter that, in operation, transmits the first converted points z1(i) and the second converted points z2(i) using a plurality of antennas.

A reception method, comprising:

• obtaining reception signals by receiving first converted signals z1(i) and second converted signals z2(i) transmitted by using plurality of antennas, where i is an integer greater than or equal to 0,
• wherein the first converted signals z1(i) and the second converted signals z2(i) are generated by converting quadrature phase shift keying (QPSK) points s1(i) and 16 quadrature amplitude modulation (QAM) points s2(i), the QPSK points s1(i) are modulated by using bits of a first stream and the 16-QAM points s2(i) are modulated by using bits of a second stream, the first converted points z1(i) and the second converted points z2(i) satisfy Equation (1), wherein the Equation (1) is defined as:
• (
• 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
• )
• )
• ,
• where y(i) is a function represented by ejδ(i), where δ(i) is a real value incremented by a constant value for every i, a value of y(i) periodically varies with a period of N, where N is 8;
• and
• demodulating the reception signals according to the conversion applied to the QPSK points s1(i) and the 16-QAM points s2(i).

A reception device, comprising:

• a receiver that, in operation, obtains reception signals by receiving first converted signals z1(i) and second converted signals z2(i) transmitted by using plurality of antennas, where i is an integer greater than or equal to 0,
• wherein the first converted signals z1(i) and the second converted signals z2(i) are generated by converting quadrature phase shift keying (QPSK) points s1(i) and 16 quadrature amplitude modulation (QAM) points s2(i), the QPSK points s1(i) are modulated by using bits of a first stream and the 16-QAM points s2(i) are modulated by using bits of a second stream, the first converted points z1(i) and the second converted points z2(i) satisfy Equation (1), wherein the Equation (1) is defined as:
• (
• 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
• )
• )
• ,
• where y(i) is a function represented by ejδ(i), where δ(i) is a real value incremented by a constant value for every i, a value of y(i) periodically varies with a period of N, where N is 8;
• and
• a demodulator that, in operation, demodulates the reception signals according to the conversion applied to the QPSK points s1(i) and the 16-QAM points s2(i).