RADIO COMMUNICATION SYSTEM, RADIO COMMUNICATION METHOD, AND RADIO COMMUNICATION DEVICE

1 . A wireless communication system comprising:

a wireless communication device circuitry and a communication partner device circuitry that establish communication by using a plurality of channels in a multiplexed manner, wherein

each of the wireless communication device circuitry and the communication partner device circuitry has a function responding to a change of a modulation scheme used for wireless communication,

the wireless communication device circuitry is configured to execute:

detecting an occurrence of an unusable state for each of the plurality of channels;

changing a working modulation scheme to another modulation scheme that generates a larger transmission capacity in a case where the unusable state is detected; and

notifying the communication partner device circuitry of the change; and

the communication partner device circuitry is configured to receive the notification and change the modulation scheme to the another modulation scheme.

2 . The wireless communication system according to claim 1 , wherein

the plurality of channels includes a plurality of working channels assumed to be used in a normal time and at least one backup channel assumed to be used as backup, and

the wireless communication device circuitry is configured to:

not instruct use of the backup channel during a period in which a working channel capacity that is a sum of transmission capacities of usable working channels satisfies a desired transmission capacity by a change of the modulation scheme;

determine whether or not the change of the modulation scheme, which causes achievement of the working channel capacity that satisfies the desired transmission capacity, is possible; and

instruct use of the backup channel in a case where the determination is denied.

3 . The wireless communication system according to claim 1 , wherein

the wireless communication device circuitry is configured to execute:

enhancing C/N that is an intensity ratio between a carrier wave and noise which are included in a wireless signal transmitted and received to and from the communication partner device circuitry, in a case where the unusable state is detected; and

the working modulation scheme is changed to the another modulation scheme after the enhancement of the C/N is executed.

4 . The wireless communication system according to claim 3 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the enhancement of the C/N is executed in a case where the current C/N does not satisfy the required C/N.

5 . The wireless communication system according to claim 4 , wherein the wireless communication device circuitry is configured to change the working modulation scheme to the another modulation scheme in a case where C/N satisfying the required C/N is obtained as a result of the enhancement of the C/N.

6 . The wireless communication system according to claim 1 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the working modulation scheme is changed to the another modulation scheme in a case where the current C/N satisfies the required C/N.

7 . A wireless communication method using a wireless communication device circuitry and a communication partner device circuitry that establish communication by using a plurality of channels in a multiplexed manner,

each of the wireless communication device circuitry and the communication partner device circuitry having a function responding to a change of a modulation scheme used for wireless communication, the wireless communication method comprising:

detecting an occurrence of an unusable state for each of the plurality of channels;

changing a working modulation scheme to another modulation scheme that generates a larger transmission capacity in a case where the unusable state is detected; and

causing the wireless communication device circuitry and the communication partner device circuitry to share the change.

8 . A wireless communication device circuitry that establishes communication with a communication partner device circuitry by using a plurality of channels in a multiplexed manner, the wireless communication device circuitry being configured to execute:

detecting an occurrence of an unusable state for each of the plurality of channels;

changing a working modulation scheme to another modulation scheme that generates a larger transmission capacity in a case where the unusable state is detected; and

notifying the communication partner device circuitry of the change.

9 . The wireless communication system according to claim 2 , wherein

the wireless communication device circuitry is configured to execute:

enhancing C/N that is an intensity ratio between a carrier wave and noise which are included in a wireless signal transmitted and received to and from the communication partner device circuitry, in a case where the unusable state is detected; and

the working modulation scheme is changed to the another modulation scheme after the enhancement of the C/N is executed.

10 . The wireless communication system according to claim 9 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the enhancement of the C/N is executed in a case where the current C/N does not satisfy the required C/N.

11 . The wireless communication system according to claim 10 , wherein the wireless communication device circuitry is configured to change the working modulation scheme to the another modulation scheme in a case where C/N satisfying the required C/N is obtained as a result of the enhancement of the C/N.

12 . The wireless communication system according to claim 2 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the working modulation scheme is changed to the another modulation scheme in a case where the current C/N satisfies the required C/N.

13 . The wireless communication system according to claim 3 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the working modulation scheme is changed to the another modulation scheme in a case where the current C/N satisfies the required C/N.

14 . The wireless communication system according to claim 4 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the working modulation scheme is changed to the another modulation scheme in a case where the current C/N satisfies the required C/N.

15 . The wireless communication system according to claim 5 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the working modulation scheme is changed to the another modulation scheme in a case where the current C/N satisfies the required C/N.

16 . The wireless communication system according to claim 9 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the working modulation scheme is changed to the another modulation scheme in a case where the current C/N satisfies the required C/N.

17 . The wireless communication system according to claim 10 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the working modulation scheme is changed to the another modulation scheme in a case where the current C/N satisfies the required C/N.

18 . The wireless communication system according to claim 11 , wherein

the wireless communication device circuitry is configured to execute:

in a case where the unusable state is detected, calculating current C/N realized at that time; and

determining whether or not the current C/N satisfies required C/N necessary in a case where the another modulation scheme is used; and

the working modulation scheme is changed to the another modulation scheme in a case where the current C/N satisfies the required C/N.