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

Abstract

A communication method of an optical communication system in which a user-side optical-line terminal apparatus (ONU) is connected to a station-side optical-line terminal apparatus (OLT) by an optical fiber includes allocating by the OLT to the ONY 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. The method also includes 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.

The invention claimed is:   
     
       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.