Communication method, optical communication system, station-side optical-line terminal apparatus, and user-side optical-line terminal apparatus

1. A communication method of an optical communication system in which a user-side optical-line terminal (ONU) apparatus is connected to a station-side optical-line terminal (OLT) apparatus by an optical fiber, comprising:

allocating, by the OLT to the ONU, a transmission bandwidth for transmitting a response signal in a tentative wake-up period in a sleep mode in which a transmission function of the ONU is activated in the tentative wake-up period and deactivated in a sleep period, and transmitting a transmission bandwidth notification to the ONU; and

transmitting, to the ONU, a notification of the sleep period in which deactivation of the transmission function is allowed.

2. The communication method according to claim 1 , wherein the ONU stops power supply to a laser of an optical transmitter in the sleep period.

3. The communication method according to claim 1 , wherein the OLT transmits, to the ONU, a signal that grants the ONU permission to transition to the sleep mode.

4. The communication method according to claim 1 , wherein when the sleep mode is continued after the sleep period, the ONU in the sleep mode transmits a signal requesting transition to the sleep mode with respect to the transmission bandwidth notification.

5. The communication method according to claim 1 , wherein the OLT causes a transmission bandwidth allocation cycle with respect to the ONU in the sleep mode to be longer than a transmission bandwidth allocation cycle with respect to the ONU not in the sleep mode.

6. An optical communication system in which a user-side optical-line terminal (ONU) apparatus is connected to a station-side optical-line terminal (OTL) apparatus by an optical fiber, wherein the OLT includes:

an optical transceiver connected to the optical fiber, and

a control device that allocates to the ONU a transmission bandwidth for transmitting a response signal in a tentative wake-up period in a sleep mode in which a transmission function of an optical transmitter of the ONU is activated in the tentative wake-up period and deactivated in a sleep period, and transmits, to the ONU, a notification of the sleep period in which deactivation of the transmission function is allowed.

7. The optical communication system according to claim 6 , wherein the ONU stops power supply to a laser of the optical transmitter in the sleep period.

8. The optical communication system according to claim 6 , wherein the OLT transmits, to the ONU, a signal that grants the ONU permission to transition to the sleep mode.

9. The optical communication system according to claim 6 , wherein when the sleep mode is continued after the sleep period, the ONU in the sleep mode transmits a signal requesting transition to the sleep mode with respect to the transmission bandwidth notification.

10. The optical communication system according to claim 6 , wherein the control device causes a transmission bandwidth allocation cycle with respect to the ONU in the sleep mode to be longer than a transmission bandwidth allocation cycle with respect to the ONU not in the sleep state.

11. A user-side optical-line terminal apparatus of an optical communication system in which a user-side optical-line terminal apparatus and a station-side optical-line terminal apparatus are connected by an optical fiber, comprising:

an optical transceiver connected to the optical fiber; and

a control device that, when a transmission bandwidth is allocated by the station-side optical-line terminal apparatus in a sleep mode, causes the optical transceiver to transmit a response signal to the station-side optical-line terminal apparatus, wherein

the control device deactivates, in the sleep mode, a transmission function of the optical transceiver in a sleep period according to a notification received from the station-side optical-line terminal apparatus and activates, in the sleep mode, the transmission function of the optical transceiver to transmit the response signal in the transmission bandwidth in a tentative wake-up period after the sleep period.

12. The user-side optical-line terminal apparatus according to claim 11 , wherein the optical transceiver stops power supply to a laser of the optical transceiver in the sleep period.

13. The user-side optical-line terminal apparatus according to claim 11 , wherein the optical transceiver operates in the sleep mode after receiving a signal that grants permission to transition to the sleep mode from the station-side optical-line terminal apparatus.

14. The user-side optical-line terminal apparatus according to claims 11 , wherein in the sleep mode, when the sleep mode is continued, the control device causes the optical transceiver to transmit a signal of requesting transition to the sleep mode as a response signal in the allocated transmission bandwidth.

15. The user-side optical-line terminal apparatus according to claim 11 , wherein the control device causes a transmission bandwidth allocation cycle in the sleep mode to be longer than a transmission bandwidth allocation cycle not in the sleep mode.

16. A station-side optical-line terminal apparatus of an optical communication system in which a user-side optical-line terminal apparatus and a station-side optical line terminal apparatus are connected an optical fiber, comprising:

an optical transceiver connected to the optical fiber; and

a control device that allocates to a user optical-line terminal apparatus a transmission bandwidth for transmitting a response signal in a tentative wake-up period in a sleep mode in which a transmission function of an optical transmitter of the user-side optical-line terminal apparatus is activated in the tentative wake-up period and deactivated in a sleep period in the sleep mode, and transmits a transmission bandwidth notification to the user-side optical-line terminal apparatus, and transmits, to the user-side optical-line terminal apparatus, a notification of the sleep period in which deactivation of the transmission function of the optical transmitter is allowed.

17. The station-side optical-line terminal apparatus according to claim 16 , wherein the control device causes the optical transceiver to transmit, to the user-side optical-line terminal apparatus, a signal that grants the user-side optical-line terminal apparatus permission to transition to the sleep mode.

18. The station-side optical-line terminal apparatus according to claim 16 , wherein the control device causes a transmission bandwidth allocation cycle with respect to the user-side optical-line terminal apparatus in the sleep mode to be longer than a transmission bandwidth allocation cycle with respect to the user-side optical-line terminal apparatus not in the sleep mode.

19. A control device of a user-side optical-line terminal apparatus of an optical communication system in which a user-side optical-line terminal apparatus and a station-side optical-line terminal apparatus are connected by an optical fiber, wherein:

the control device controls an optical transceiver of the user-side optical-line terminal apparatus and causes the optical transceiver to transmit a response signal to the station-side optical-line terminal apparatus, and

when a transmission bandwidth is allocated by the station-side optical-line terminal apparatus in a sleep mode, the control device deactivates a transmission function of the user-side optical-line terminal apparatus in a sleep period according to a notification received from the station-side optical-line terminal apparatus and activates the transmission function to transmit the response signal in the transmission bandwidth in a tentative wake-up period after the sleep period.

20. The control device according to claim 19 , wherein the control device causes power supply to a laser of the optical transceiver to be stopped in the sleep period.

21. The control device according to claim 19 , wherein the control device causes the optical transceiver to be operated in the sleep mode after receiving a signal that grants permission to transition to the sleep mode from the station-side optical-line terminal apparatus.

22. The control device according to claim 19 , wherein in the sleep mode, when the sleep mode is continued after the sleep period, the control device causes the optical transceiver to transmit a signal of requesting transition to the sleep mode as a response signal in the allocated transmission bandwidth.

23. A control device of a station-side optical-line terminal apparatus of an optical communication system in which a user-side optical-line terminal apparatus and a station-side optical-line terminal apparatus are connected by an optical fiber, wherein:

the control device allocates to the user-side optical-line terminal apparatus a transmission bandwidth for transmitting a response signal in a tentative wake-up period in a sleep mode in which a transmission function of an optical transmitter of the user-side optical-line terminal apparatus is activates in the tentative wake-up period and deactivated in a sleep period, and transmits a transmission bandwidth notification to the user-side optical-line terminal apparatus, and

transmits, to the user-side optical-line terminal apparatus, a notification of the sleep period in which deactivation of the transmission function is allowed.

24. The control device according to claim 23 , wherein the control device causes the optical transceiver to transmit, to the user-side optical-line terminal apparatus, a signal that grants the user-side optical-line terminal apparatus permission to transition to the sleep mode.

25. The control device according to claim 23 , wherein the control device causes a transmission bandwidth allocation cycle with respect to the user-side optical-line terminal apparatus transitioned to the sleep mode to be longer than a transmission bandwidth allocation cycle with respect to the user-side optical-line terminal apparatus not in the sleep mode.