PON system, optical network unit, optical line terminal, method of registering optical network unit, and data structure

Patent metadata

Field	Value
Publication number	US-11070295-B2
Application number	US-201816765715-A
Country	US
Kind code	B2
Filing date	Sep 25, 2018
Priority date	Nov 22, 2017
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

A PON system according to one manner of the present invention includes an optical line terminal (OLT), at least one optical network unit (ONU), and an optical fiber that connects the optical line terminal and the optical network unit to each other. A reception level category for categorizing a reception level in the optical network unit, of an optical signal sent from the optical line terminal through the optical fiber is set. In discovery processing for searching for and registering an unregistered optical network unit, the optical line terminal registers an optical network unit corresponding to the reception level category.

First claim

The invention claimed is:

1. A PON system comprising:
an optical line terminal;
at least one optical network unit; and
an optical fiber that connects the optical line terminal and the optical network unit to each other, wherein
the optical network unit determines a reception level category that categorizes a reception level of an optical signal at the optical network unit, the optical signal being sent from the optical line terminal through the optical fiber, and
the optical line terminal configured to perform discovery processing, the discovery processing including designating the reception level category, searching for an unregistered optical network unit, and registering the unregistered optical network unit corresponding to the reception level category,
the unregistered optical network unit configured to respond to the optical line terminal when the reception level designated by the optical line terminal corresponds to the determined reception level category.

2. The PON system according to claim 1 , wherein
the unregistered optical network unit determines the reception level category based on the reception level.

3. The PON system according to claim 1 , wherein
the optical line terminal includes an amplifier that amplifies the optical signal received from the optical network unit with a variable gain and designates the reception level category in the discovery processing,
the reception level category is associated with the gain of the amplifier, and
the unregistered optical network unit attempts to respond to the discovery processing in an ascending order of the gain of the amplifier, and the reception level category designated in the discovery processing under which response is successful is set as the reception level category of the unregistered optical network unit.

4. The PON system according to claim 1 , wherein
the optical line terminal determines the reception level category, and the optical line terminal includes an amplifier that amplifies the optical signal received from the optical network unit with a variable gain,
the reception level category is brought in correspondence with one gain level category or a plurality of gain level categories of the gain, and
when the plurality of gain level categories are allocated to a single reception level category, the unregistered optical network unit attempts to respond to the discovery processing in an ascending order of the plurality of gain level categories.

5. The PON system according to claim 4 , wherein
the optical line terminal transmits the reception level category determined by the optical line terminal to the optical network unit.

6. The PON system according to claim 4 , wherein
when the unregistered optical network unit has responded to the discovery processing, the optical line terminal determines whether the unregistered optical network unit can be registered.

7. The PON system according to claim 6 , wherein
determination by the optical line terminal includes comparison of a frequency of correction in error correction processing with a threshold value.

8. The PON system according to claim 1 , wherein
the reception level category is determined based on reception power of the optical network unit.

9. The PON system according to claim 1 , wherein
the reception level category is determined based on line loss of the optical fiber that corresponds to a difference between transmission power of the optical line terminal and reception power of the optical network unit.

10. The PON system according to claim 1 , wherein
the reception level category is determined based on a maximum value of the reception level of the optical network unit and a minimum value of the reception level of the optical network unit.

11. The PON system according to claim 10 , wherein
when the optical line terminal performs the discovery processing, the optical line terminal incorporates the maximum value and the minimum value into a discovery gate message.

12. The PON system according to claim 10 , wherein
at least one of the maximum value and the minimum value is variable.

13. The PON system according to claim 10 , wherein
the optical line terminal changes the reception level category from a first category to a second category overlapping in range with the first category, and
when the reception level of the optical network unit is included in both of the first category and the second category, the optical network unit responds to the optical line terminal at time when the reception level category higher in reception level, of the first category and the second category, is determined.

14. The PON system according to claim 10 , wherein
the optical network unit measures the reception level of the optical network unit and determines whether the reception level corresponds to the reception level category based on a measured value of the reception level.

15. The PON system according to claim 10 , wherein
the reception level category is determined based on line loss of the optical fiber that corresponds to a difference between transmission power of the optical line terminal and reception power of the optical network unit.

16. The PON system according to claim 10 , wherein
the optical line terminal sets a plurality of times, a set of the maximum value and the minimum value,
a plurality of sets of the maximum value and the minimum value include a first set and a second set that satisfy relation that the maximum value of the second set is larger than the minimum value of the first set, and
the optical line terminal performs the discovery processing for the plurality of sets in a descending order of the maximum value.

17. A PON system comprising:
an optical line terminal;
at least one optical network unit; and
an optical fiber that connects the optical line terminal and the optical network unit to each other,
the optical line terminal including an amplifier that receives an optical signal from the optical network unit and amplifies an output signal with a variable gain, and determining and registering a category of the gain in discovery processing, wherein
in the discovery processing, the optical line terminal sets a reception level category corresponding to the category of the gain of the amplifier,
an unregistered optical network unit attempts to respond to the discovery processing when a reception level of an optical signal at the unregistered optical network unit corresponds to the reception level category, and
when response from the unregistered optical network unit has been acknowledged, the optical line terminal sets the gain category for the unregistered optical network unit.

18. The PON system according to claim 17 , wherein
the optical line terminal repeatedly makes setting of the gain of the amplifier in the discovery processing and sets the gain category for the optical network unit from which the response has been acknowledged at a gain lower than the registered gain category.

19. The PON system according to claim 17 , wherein
when intensity of the output signal amplified by the amplifier is higher than a threshold value, the optical line terminal selects the gain category lowest in gain and sets again the gain category.

20. The PON system according to claim 1 , wherein
the optical network unit monitors the reception level of the optical network unit, and when the reception level exceeds a threshold value, the optical network unit stops optical output, and
the optical line terminal determines that the optical network u

Assignees

• Sumitomo Electric Industries

Inventors

• Funada Tomoyuki
• Umeda Daisuke
• Jinen Keisuke
• Tanaka Naruto
• Kawase Daisuke

Classifications

• H04Q2011/0064

  Arbitration, scheduling or medium access control aspects · CPC title

• H04B10/67 Primary

  Optical arrangements in the receiver · CPC title

• H04Q11/0067 Primary

  Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring · CPC title

• H04B10/272

  Star-type networks {or tree-type networks} · CPC title

• H04B10/27

  Arrangements for networking · CPC title