Communication device and communication method

1. A communication device comprising circuitry configured to:

perform wireless communication;

acquire information regarding a communication quality of one or more radio links including at least one of a direct first radio link, or a second radio link via a relay terminal, which is movable, between a remote terminal and a base station, information regarding the communication quality of the second radio link includes information regarding a communication quality of a third radio link between the remote terminal and the relay terminal;

acquire information regarding the communication quality of the third radio link in accordance with an estimation result of the communication quality based on a first threshold value for evaluating whether or not the communication quality reaches a predetermined level, a second threshold value for evaluating whether or not the communication quality no longer reaches a predetermined level, and a measurement result regarding the communication quality of the third radio link; and

switch the radio link to be used in communication between the remote terminal and the base station on a basis of the acquired information regarding the communication quality.

2. The communication device according to claim 1 , in which at least one of the first threshold value or the second threshold value is set by the base station or the relay terminal.

3. The communication device according to claim 1 , wherein a resource for measurement of the communication quality is set by the base station or the relay terminal.

4. The communication device according to claim 1 ,

wherein the communication device is one communication terminal of the remote terminal and the relay terminal, and

the circuitry is configured to measure the information regarding the communication quality of the third radio link from the other communication terminal different from the one communication terminal.

5. The communication device according to claim 1 ,

wherein the communication device is one communication terminal of the remote terminal and the relay terminal, and

the circuitry is configured to acquire the communication quality of the third radio link and the information regarding the communication quality of the third radio link in accordance with the estimation result based on the measurement result, the first threshold value, and the second threshold value.

6. The communication device according to claim 5 , wherein the circuitry is configured to intermittently measure a communication quality of a resource pool associated with the third radio link in time series and acquire the information regarding the communication quality of the third radio link on a basis of the measurement result.

7. The communication device according to claim 6 , wherein the circuitry is configured to measure a communication quality of each of a plurality of the resource pools associated with the third radio link in time series.

8. The communication device according to claim 1 ,

wherein the communication device is the base station, and

the circuitry is configured to acquire the information regarding the communication quality of the third radio link from the remote terminal or the relay terminal.

9. The communication device according to claim 1 , wherein, of the information regarding the communication quality of the second radio link, the circuitry is configured to acquire information regarding the communication quality of a fourth radio link between the relay terminal and the base station on a basis of a measurement result regarding the communication quality of the fourth radio link.

10. The communication device according to claim 9 ,

wherein the communication device is the remote terminal, and

the circuitry is configured to acquire the information regarding the communication quality of the fourth radio link by determining the communication quality of the fourth radio link on a basis of a second criterion that is different from a first criterion for the communication quality of the direct first radio link.

11. The communication device according to claim 10 , wherein the second criterion is set such that degradation or improvement of the communication quality of the fourth radio link is determined on a basis of a smaller change in the communication quality than in a case in which the communication quality of the direct first radio link is determined.

12. The communication device according to claim 10 , wherein the second criterion is set by the base station.

13. The communication device according to claim 10 , wherein the circuitry is configured to calculate the second criterion on a basis of the first criterion.

14. The communication device according to claim 9 ,

wherein the communication device is the relay terminal or the base station, and

the circuitry is configured to acquire the information regarding the communication quality of the fourth radio link by measuring the communication quality of the fourth radio link.

15. The communication device according to claim 9 ,

wherein the communication device is one communication terminal of the remote terminal and the relay terminal, and

the circuitry is configured to acquire the information regarding the communication quality of the fourth radio link from the other communication terminal that is different from the one communication terminal.

16. The communication device according to claim 1 ,

wherein the communication device is the relay terminal, and

the circuitry is configured to perform control such that, in a case in which the radio link to be used in communication between the remote terminal and the base station is switched from the second radio link via a first relay terminal to the second radio link via a second relay terminal that is different from the first relay terminal, the second relay terminal is notified of a request for the switch directly or indirectly via the base station.

17. The communication device according to claim 16 ,

wherein the circuitry is configured to

perform control such that the second relay terminal is directly notified of the request for the switch in a case in which the second relay terminal is discovered on a basis of a search result for another relay terminal located in a vicinity, and

perform control such that the second relay terminal is indirectly notified of the request for the switch via the base station in a case in which the second relay terminal is not discovered.

18. A communication device comprising circuitry configured to:

perform wireless communication;

acquire information regarding a communication quality of at least one of a direct first radio link or a second radio link via a relay terminal, which is movable, between a remote terminal and a base station, information regarding the communication quality of the second radio link includes information regarding a communication quality of a third radio link between the remote terminal and the relay terminal;

acquire information regarding the communication quality of the third radio link in accordance with an estimation result of the communication quality based on a first threshold value for evaluating whether or not the communication quality reaches a predetermined level, a second threshold value for evaluating whether or not the communication quality no longer reaches a predetermined level, and a measurement result regarding the communication quality of the third radio link; and

directly or indirectly notify an external device that switches the radio link to be used in communication between the remote terminal and the base station of the acquired information regarding the communication quality.

19. The communication device according to claim 18 ,

wherein the communication device is the relay terminal, and

the circuitry is configured to notify the remote terminal of the acquired information regarding the communication quality directly or indirectly via the base station.

20. The communication device according to claim 18 ,

wherein the communication device is the remote terminal, and

the circuitry is configured to notify the relay terminal of the acquired information regarding the communication quality directly or indirectly via the base station.

21. A communication device comprising circuitry configured to:

perform wireless communication;

allocate a resource for communication between a first relay terminal and a second relay terminal in a case in which, on a basis of information regarding a communication quality of one or more radio links including at least one of a direct first radio link or a second radio link via a relay terminal, which is movable, between a remote terminal and a base station, information regarding the communication quality of the second radio link includes information regarding a communication quality of a third radio link between the remote terminal and the relay terminal;

acquire information regarding the communication quality of the third radio link in accordance with an estimation result of the communication quality based on a first threshold value for evaluating whether or not the communication quality reaches a predetermined level, a second threshold value for evaluating whether or not the communication quality no longer reaches a predetermined level, and a measurement result regarding the communication quality of the third radio link; and

decide that the radio link to be used in communication between the remote terminal and the base station is to be switched from the second radio link via the first relay terminal to the second radio link via the second relay terminal.

22. A communication method comprising:

performing wireless communication;

acquiring, by a computer, information regarding a communication quality of one or more radio links including at least one of a direct first radio link or a second radio link via a relay terminal, which is movable, between a remote terminal and a base station via wireless communication, information regarding the communication quality of the second radio link includes information regarding a communication quality of a third radio link between the remote terminal and the relay terminal;

acquiring, by a computer, information regarding the communication quality of the third radio link in accordance with an estimation result of the communication quality based on a first threshold value for evaluating whether or not the communication quality reaches a predetermined level, a second threshold value for evaluating whether or not the communication quality no longer reaches a predetermined level, and a measurement result regarding the communication quality of the third radio link; and

switching the radio link to be used in communication between the remote terminal and the base station on a basis of the acquired information regarding the communication quality.

23. A communication method comprising:

performing wireless communication;

acquiring, by a computer, information regarding a communication quality of at least one of a direct first radio link or a second radio link via a relay terminal, which is movable, between a remote terminal and a base station via wireless communication, information regarding the communication quality of the second radio link includes information regarding a communication quality of a third radio link between the remote terminal and the relay terminal;

acquiring, by a computer, information regarding the communication quality of the third radio link in accordance with an estimation result of the communication quality based on a first threshold value for evaluating whether or not the communication quality reaches a predetermined level, a second threshold value for evaluating whether or not the communication quality no longer reaches a predetermined level, and a measurement result regarding the communication quality of the third radio link; and

directly or indirectly notifying an external device that switches the radio link to be used in communication between the remote terminal and the base station of the acquired information regarding the communication quality.

24. A communication method comprising:

performing wireless communication;

allocating, by a computer, a resource for communication between a first relay terminal and a second relay terminal in a case in which, on a basis of information regarding a communication quality of one or more radio links including at least one of a direct first radio link or a second radio link via a relay terminal, which is movable, between a remote terminal and a base station, information regarding the communication quality of the second radio link includes information regarding a communication quality of a third radio link between the remote terminal and the relay terminal, information regarding the communication quality of the third radio link in accordance with an estimation result of the communication quality based on a first threshold value for evaluating whether or not the communication quality reaches a predetermined level, a second threshold value for evaluating whether or not the communication quality no longer reaches a predetermined level, and a measurement result regarding the communication quality of the third radio link; and

deciding that the radio link to be used in communication between the remote terminal and the base station is to be switched from the second radio link via the first relay terminal to the second radio link via the second relay terminal.