Method and apparatus for setting quiet window in passive optical network system

1. A method for setting a quiet window in a passive optical network system, comprising:

measuring a first response time from a time after an optical line terminal (OLT) transmits a serial number request up to a time in which the OLT receives a first response signal to the serial number request;

measuring a second response time up to a time in which the OLT receives a final response signal to the serial number request; and

adjusting the quiet window on the basis of distance information of the an Optical Network Unit (ONU) including the first response time and the second response time,

wherein the adjusting of the quiet window includes:

adjusting a time in which the OLT transmits the serial number request by using the first response time; and

adjusting a time in which the OLT transmits an empty by using the second response time.

2. The method for setting a quiet window of claim 1 , wherein:

the method for setting a quiet window is performed in a serial number acquisition process of the OLT, and the measuring of the first response time and the second response time in the serial number acquisition process is performed per set period.

3. The method for setting a quiet window of claim 1 , wherein:

in the adjusting of the quiet window, a time in which the quiet window is opened is adjusted by adjusting times in which the empty and the serial number request are transmitted on the basis of the distance information of the ONU.

4. The method for setting a quiet window of claim 1 , wherein:

the adjusting of the time in which the OLT transmits the serial number request by using the first response time includes:

adjusting the time in which the OLT transmits the serial number request depending on a first time calculated by using the first response time; and

adjusting of the time in which the OLT transmits an empty by using the second response time includes adjusting a time in which the OLT transmits the empty depending on a second time calculated by using the second response time.

5. The method for setting a quiet window of claim 4 , wherein:

the first time is calculated according to a condition of S=Clock_count T 1 −(max_random_delay+α), and the second time is calculated according to a condition of E=Clock_count T 2 +(max_random_delay+α), where Clock_count T 1 indicates a first count value of a count using a clock counted from a count start up to the first response time, Clock_count (T 2 ) indicates a second count value of the count counted from the count start up to the second response time, and α indicates a delay time of the ONU.

6. The method for setting a quiet window of claim 1 , wherein:

the measuring of the first response time includes:

starting a count using a clock when a predetermined number of frames elapse and the quiet window is opened after the serial number request is transmitted; and

measuring the first response time using a first count value of the count counted from a time in which the count is started up to a time in which the first response signal is received, and

the measuring of the second response time includes measuring the second response time using a second count value of the count counted from the time in which the count is started up to a time in which the final response signal is received.

7. A method for registering an Optical Network Unit (ONU) by an Optical Line Termination (OLT) in a passive optical network system, comprising:

performing a serial number acquisition process in which the OLT transmits a serial number request and receives a response to the serial number request from the ONU; and

performing a ranging process on ONUs of which serial numbers are acquired to transmit corresponding delay values to the ONUs,

wherein the performing of the serial number acquisition process includes:

measuring a first response time from a time in which the OLT transmits the serial number request up to a time in which the OLT receives a first response signal;

measuring a second response time up to a time in which the OLT receives a final response signal to the serial number request;

and

adjusting a quiet window on the basis of distance information of an Optical Network Unit (ONU) including the first response time and the second response time,

wherein the adjusting of the quiet window includes:

adjusting a time in which the OLT transmits the serial number request by using the first response time; and

adjusting a time in which the OLT transmits an empty by using the second response time.

8. The method for registering an ONU of claim 7 , wherein:

the adjusting of the time in which the OLT transmits the serial number request by using the first response time includes:

adjusting the time in which the OLT transmits the serial number request depending on a first time calculated by using the first response time; and

adjusting the time in which the OLT transmits the empty by using the second response time includes adjusting the time in which the OLT transmits the empty depending on a second time calculated by using the second response time.

9. The method for registering an ONU of claim 8 , wherein:

the first time is calculated according to a condition of S=Clock_count T 1 −(max_random_delay+α), and the second time is calculated according to a condition of E=Clock_count T 2 +(max_random_delay+α), where Clock_count T 1 indicates a first count value of a count using a clock counted from a count start up to the first response time, Clock_count T 2 indicates a second count value of the count counted from the count start up to the second response time, and α indicates a delay time of the ONU.

10. An apparatus for setting a quiet window in a passive optical network system, comprising:

a signal transceiver transmitting and receiving an optical signal; and

a processor connected to the signal transceiver and executing setting of the quiet window,

wherein the processor is configured to

measure a first response time from a time after a serial number request is transmitted up to a time in which a first response signal to the serial number request is received,

measure a second response time up to a time in which a final response signal to the serial number request is received, and

adjust the quiet window on the basis of distance information of an Optical Network Unit (ONU) including the first response time and the second response time, and

wherein the processor is configured to adjust a time in which the Optical Line Termination (OLT) transmits the serial number request by using the first response time and adjust a time in which the OLT transmits an empty by using the second response time.

11. The apparatus for setting a quiet window of claim 10 , wherein:

the processor is configured to perform acquisition of the distance information of the ONU in a serial number acquisition process of an Optical Line Termination (OLT) per set period.

12. The apparatus for setting a quiet window of claim 10 , wherein:

the processor is configured to adjust a time in which the quiet window is opened by adjusting times in which the empty and the serial number request are transmitted on the basis of the distance information of the ONU.

13. The apparatus for setting a quiet window of claim 10 , wherein:

the processor is configured to adjust the time in which the OLT transmits the serial number request depending on a first time calculated by using the first response time and adjust the time in which the OLT transmits the empty depending on a second time calculated by using the second response time.

14. The apparatus for setting a quiet window of claim 13 , wherein:

the first time is calculated according to a condition of S=Clock_count T 1 −(max_random_delay+α), and the second time is calculated according to a condition of E=Clock_count T 2 +(max_random_delay+α), where Clock_count T 1 indicates a first count value of a count using a clock counted from a count start up to the first response time, Clock_count T 2 indicates a second count value of the count counted from the count start up to the second response time, and α indicates a delay time of the ONU.

15. The apparatus for setting a quiet window of claim 10 , wherein:

the processor is configured to start a count using a clock when a predetermined number of frames elapse and the quiet window is opened after the serial number request is transmitted, measure the first response time using a first count value of the count counted from a time in which the count is started up to a time in which the first response signal is received, and measure the second response time using a second count value of the count counted from the time in which the count is started up to a time in which the final response signal is received.