WIRELESS COMMUNICATION METHOD, WIRELESS COMMUNICATION SYSTEM, AND WIRELESS TRANSMISSION DEVICE

1 . A wireless communication method using a wireless transmitter and a wireless receiver that support at least two multi-level modulation schemes,

the at least two multi-level modulation schemes including a first modulation scheme and a second modulation scheme having a shorter minimum Euclidean distance on a constellation and a lower peak to average power ratio (PAPR) than the first modulation scheme, and

the wireless transmitter having a function of controlling a power amplifier to change transmission power, the wireless communication method comprising:

determining, by the wireless transmitter, the transmission power;

comparing, by the wireless transmitter, the transmission power with a threshold value set on the basis of a boundary point at which a linear region and a nonlinear region of the power amplifier are switched;

selecting, by the wireless transmitter, the first modulation scheme as a multi-level modulation scheme used for communication when the transmission power is not greater than the threshold value;

selecting, by the wireless transmitter, the second modulation scheme as a multi-level modulation scheme used for communication when the transmission power is greater than the threshold value;

commanding, by the wireless transmitter, the wireless receiver to perform communication using the selected modulation scheme; and

communicating, by the wireless receiver, with the wireless transmitter using the commanded modulation scheme.

2 . The wireless communication method according to claim 1 , wherein the threshold value is a value obtained by applying back-off corresponding to a first PAPR, which is a PAPR of the first modulation scheme, to transmission power corresponding to the boundary point.

3 . The wireless communication method according to claim 2 , wherein the first PAPR is a convergence value for the first modulation scheme.

4 . The wireless communication method according to claim 3 , wherein the first PAPR is a value set to allow generation of a symbol with peak power exceeding a value of the first PAPR at a probability corresponding to required communication quality.

5 . The wireless communication method according to claim 2 , wherein the first PAPR is calculated on the basis of a plurality of symbols generated within a range divided by a predetermined rule, and is updated at a predetermined cycle.

6 . The wireless communication method according to claim 1 , wherein the first modulation scheme and the second modulation scheme are QAM and APSK having the same number of symbols.

7 . A wireless communication system comprising a wireless transmitter and a wireless receiver that support at least two multi-level modulation schemes, wherein

the at least two multi-level modulation schemes include a first modulation scheme and a second modulation scheme having a shorter minimum Euclidean distance on a constellation and a lower PAPR than the first modulation scheme,

the wireless transmitter

has a function of controlling a power amplifier to change transmission power, and

being configured to execute:

determining the transmission power;

comparing the transmission power with a threshold value set on the basis of a boundary point at which a linear region and a nonlinear region of the power amplifier are switched;

selecting the first modulation scheme as a multi-level modulation scheme used for communication when the transmission power is not greater than the threshold value;

selecting the second modulation scheme as a multi-level modulation scheme used for communication when the transmission power is greater than the threshold value; and

commanding the wireless receiver to perform communication using the selected modulation scheme, and

the wireless receiver is configured to communicate with the wireless transmitter using the commanded modulation scheme.

8 . A wireless transmitter that supports at least two multi-level modulation schemes and has a function of communicating with a wireless receiver that supports the at least two multi-level modulation schemes, wherein

the at least two multi-level modulation schemes include a first modulation scheme and a second modulation scheme having a shorter minimum Euclidean distance on a constellation and a lower PAPR than the first modulation scheme, and

the wireless transmitter

has a function of controlling a power amplifier to change transmission power, and

being configured to execute:

determining the transmission power;

comparing the transmission power with a threshold value set on the basis of a boundary point at which a linear region and a nonlinear region of the power amplifier are switched;

selecting the first modulation scheme as a multi-level modulation scheme used for communication when the transmission power is not greater than the threshold value;

selecting the second modulation scheme as a multi-level modulation scheme used for communication when the transmission power is greater than the threshold value; and

commanding the wireless reception device receiver to perform communication using the selected modulation scheme.

9 . The wireless communication method according to claim 2 , wherein the first modulation scheme and the second modulation scheme are QAM and APSK having the same number of symbols.

10 . The wireless communication method according to claim 3 , wherein the first modulation scheme and the second modulation scheme are QAM and APSK having the same number of symbols.

11 . The wireless communication method according to claim 4 , wherein the first modulation scheme and the second modulation scheme are QAM and APSK having the same number of symbols.

12 . The wireless communication method according to claim 5 , wherein the first modulation scheme and the second modulation scheme are QAM and APSK having the same number of symbols.