# US 2008/0187312 A1 · Passive optical network system and operating method thereof

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2008/0187312 A1
- Document ID: US20080187312A1
- Status: Published application
- Kind: A1
- Application number: 11/806,130
- Filed: 2007-05-30
- Published: 2008-08-07
- Earliest claimed: 2007-02-02
- Assignees: Hitachi Communication Tehcnologies, Ltd.
- Inventors: Tohru Kazawa; Masaki Ohira; Yusuke Yajima
- Web page: https://patentgrep.com/patent/US20080187312A1

## CPC

- H04J 3/1694: {Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers (Passive Optical Networks H04Q11/0062)}
- H04Q 11/0067: {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}
- H04Q 2011/0079: {Operation or maintenance aspects}
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)
- H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W)

## Abstract

A Passive Optical Network system implementing a parent station capable of receiving high-speed burst signals transmitted from a plurality of subsidiary stations to a parent station, with excellent bandwidth utilization efficiency in the link from the stations to the parent. The system is provided with a configuration in which, when launched or an addition of a new subsidiary station, the parent stores threshold values appropriate for the received signals on the basis of the strength of the received signal for each subsidiary station, from among a plurality of preset threshold value candidates, and in response to the parent station's sending of a transmission grant with respect to each subsidiary station each time the subsidiary station transmitting optical signals changes, the stored threshold value corresponding to the subsidiary station is set in the receiver circuit.

## Claims

### Claim 1

A Passive Optical Network system for connecting a parent station and each of a plurality of subsidiary stations by means of an optical fiber network including an optical splitter, wherein said parent station is provided with:
a receiver circuit receiving optical signals from each of said plurality of subsidiary stations by using threshold values discriminating 0's and 1's;
and a control part including: both a bandwidth setting part deciding on the timing with which each of said plurality of subsidiary stations transmits optical signals and reporting the same to each of said subsidiary stations; and a threshold value management part providing a plurality of optical signal threshold value candidates and selecting and storing, from among said plurality of threshold value candidates, threshold values with respect to the subsidiary stations with which optical signals are received from each of said plurality of subsidiary stations;
and wherein said control part, at the time of receiving an optical signal from an arbitrary subsidiary station, sets, in said receiver circuit, the threshold value corresponding to said subsidiary station which is stored in said threshold value management part, on the basis of the timing decided on by said bandwidth setting part, if the optical signal transmission of a separate subsidiary station transmitting an optical signal before said subsidiary station comes to an end.

### Claim 2 (depends on 1)

The Passive Optical Network system according to claim 1, wherein said control part, at the time of the initial setting of said Passive Optical Network system, or at the time of connecting a new subsidiary station, selects and stores, on the basis of a rule prescribed by said threshold value management part, a threshold value corresponding to each of said plurality of subsidiary stations from among said plurality of threshold value candidates.

### Claim 3 (depends on 2)

The Passive Optical Network system according to claim 2, wherein said control part is provided with a counter measuring the time period during which a threshold value corresponding to an arbitrary subsidiary station is selected from among said plurality of threshold value candidates and dividing the time period into a plurality of intervals and, when said counter detects the switchover from the first interval to the second interval, switches to and sets, from among said plurality of threshold value candidates, the threshold value set in said receiver circuit in said second interval to be a threshold value equal to or below the threshold value set in said first interval and stores, as the threshold value corresponding to said subsidiary station, the threshold value with which it has been possible to receive an optical signal from said subsidiary station.

### Claim 4

An operating method of a Passive Optical Network system connecting a parent station and a plurality of subsidiary stations by means of an optical fiber network including an optical splitter, wherein said parent station: at the time of the initial setting of said Passive Optical Network system, selects and stores threshold values, discriminating as 0's or 1's the optical signals received from each of said connected plurality of subsidiary stations, to correspond to said plurality of subsidiary stations, from among a plurality of threshold value candidates;
during operation, decides on the timing with which each of said plurality of subsidiary stations transmits optical signals and reports the same to each of said plurality of subsidiary stations;
and receives, at the time of receiving an optical signal from an arbitrary subsidiary station, optical signals from each subsidiary station by setting, in said receiver circuit, the threshold value corresponding to said stored subsidiary station, on the basis of said decided timing, if the optical signal transmission of a separate subsidiary station transmitting an optical signal before said subsidiary station comes to an end.

### Claim 5 (depends on 4)

The operating method of a Passive Optical Network system according to claim 4, wherein said parent station, also at the time of connection of a new subsidiary station, selects and stores, from among a plurality of threshold values, a threshold value discriminating as 0's or 1's optical signals received from said subsidiary station, and during operation of said subsidiary station, receives optical signals from said subsidiary station by setting the stored threshold value of said subsidiary station in said receiver circuit on the basis of said decided timing, if the optical signal transmission of a separate subsidiary station transmitting an optical signal before said subsidiary station comes to an end.

### Claim 6 (depends on 5)

The operating method of a Passive Optical Network system according to claim 5, wherein:
the time period during which a threshold value corresponding to an arbitrary subsidiary station is selected from among said plurality of threshold value candidates is divided into a plurality of intervals; when time passes from the first interval to the second interval, the threshold value set in said receiver circuit in said second interval is switched over and set to a threshold value equal to or lower than the threshold value set in said first interval, from among said plurality of threshold value candidates; and the threshold value for which the receiver of optical signals from said subsidiary station was successful is stored as a threshold value corresponding to said subsidiary station.

### Claim 7

A Passive Optical Network system connecting a parent station and a plurality of subsidiary stations by means of an optical fiber network including an optical splitter, wherein said parent station is constituted by:
a wavelength multiplexing filter transmitting and receiving optical signals to and from each of said plurality of subsidiary stations;
a receiver circuit receiving, using a threshold value discriminating as 0's or 1's, an optical signal coming from each of said plurality of subsidiary stations through said wavelength multiplexing filter and constituted by overhead and burst data consisting of a control signal and a main signal, and outputting said burst data;
a frame disassembly circuit separating said received burst data into said control signal and main signal;
a frame assembly circuit assembling said plurality of main signals and control signals, destined for said plurality of subsidiary stations, into a frame signal;
an electrical/optical circuit converting said frame signal into an optical signal and sending it through said wavelength multiplexing filter to said plurality of subsidiary stations;
a network interface connecting a host network and said parent station; and
a control part carrying out control of said parent station as a whole;
wherein said control part is provided with a plurality of optical signal threshold value candidates and selects and stores, corresponding to the subsidiary station, threshold values with which optical signals from each of said plurality of subsidiary stations are received from among said plurality of threshold value candidates;
and decides on the timing with which each of said plurality of subsidiary stations transmits optical signals and reports the same to said plurality of subsidiary stations through said frame assembly circuit;
and which, during receiver of optical signals from an arbitrary subsidiary station, sets, in said receiver circuit, a threshold value corresponding to said stored subsidiary station, on the basis of said decided timing, to receive optical signals from said plurality of subsidiary stations, if the optical signal transmission of a separate subsidiary station transmitting an optical signal before said subsidiary station comes to an end.

### Claim 8 (depends on 7)

The Passive Optical Network system according to claim 7, wherein said control part consists of:
a bandwidth setting part deciding on the timing with which each of said plurality of subsidiary stations transmits optical signals and reporting the same to each of said plurality of subsidiary stations; and a threshold value management part, provided with said plurality of optical signal threshold value candidates, and selecting and storing, from among said plurality of threshold value candidates, threshold values corresponding to the subsidiary station with which optical signals from each of said plurality of subsidiary stations are received; and
sets, during receiver of optical signals from an arbitrary subsidiary station, the threshold values corresponding to said subsidiary station stored by said threshold value management part in said receiver circuit, on the basis of the decided timing of said bandwidth setting part, if the optical signal transmission of a separate subsidiary station transmitting an optical signal before said subsidiary station comes to an end.

### Claim 9 (depends on 8)

The Passive Optical Network system according to claim 8, wherein said control part is provided with a counter measuring the time period during which a threshold value corresponding to an arbitrary subsidiary station is selected from among said plurality of threshold value candidates and dividing the time period into a plurality of intervals and, if said counter detects the switchover from the first interval to the second interval, switches to and sets, from among said plurality of threshold value candidates, the threshold value set in said receiver circuit in said second interval to be a threshold value equal to or below the threshold value set in said first interval and stores, as the threshold value corresponding to said subsidiary station, the threshold value with which it has been possible to receive an optical signal from said subsidiary station.