KR101078054B1 - Optical line termination apparatus and method for control of abnormal optical network unit in TDM PON - Google Patents

Abstract

The present invention relates to an apparatus and method for detecting and remotely blocking a subscriber station transmitting an abnormal uplink signal. An optical transceiver for transmitting and receiving an uplink or downlink signal with a plurality of optical network units (ONUs) according to the present invention, and continuous for at least a threshold time from at least one subscriber station of the plurality of subscriber stations through the optical transceiver When the uplink signal is received, the subscriber station transmitting a continuous uplink signal is requested, and the remote node (Remote Node: RN) connected to a plurality of subscriber stations to block the uplink signal transmission of the detected subscriber station It characterized in that it comprises a control unit.

Time Division Multiplexing, Passive Optical Subscriber Network, Fiber Optic Termination Device, Subscriber Terminal

Description

Optical line termination apparatus and method for control of abnormal optical network unit in TDM PON}

The present invention relates to a device and a method for detecting and blocking a subscriber station transmitting an abnormal uplink signal, and more particularly, to detect a subscriber station transmitting an abnormal uplink signal in a time division multiplexing passive subscriber network system and remotely. A light ray termination device and method are provided.

This study was derived from the research conducted as part of the original technology development project of the Ministry of Knowledge Economy and the Korea Institute of Information and Telecommunications Promotion. [Task name: FTTH Service Development Experiment Project]

Passive optical network (PON) system is an optical subscriber network technology that provides high-speed services based on optical fiber to enterprises, small office home offices, and general homes. It is called passive optical subscriber network. The general structure of a PON is provided with an optical line termination (OLT) installed in a central office (CO), connected to a remote node (RN) through an optical fiber, and a plurality of optical terminals. network units (ONU) are connected as 1: N.

Such a PON system is based on a PON of Time Devision Multiplexing (TDM) and a Wave Devision Multiplexing (WDM) according to a method of sharing optical fiber media between subscriber stations and remote nodes. It is divided into PON.

The WDM PON system is used for remote nodes in the AWG and shares the optical fiber between the fiber termination device and the remote node in a wavelength division multiplexed manner. Accordingly, communication between each of the optical path terminators and the subscriber station is performed using a specific optical wavelength, and operates in a 1: 1 connection method. Such a WDM PON system does not seriously affect the communication of other subscriber stations even when an abnormal uplink transmission occurs due to a failure of a specific subscriber station. That is, when an error occurs in the optical transmitter of the subscriber station, the WDM PON system only affects communication between the corresponding subscriber station and the optical fiber termination device, and does not affect the communication of other subscriber stations.

TDM PON systems, on the other hand, use an optical power divider at a remote node and share the optical fiber between the optical fiber terminator and the optical power divider in a time division multiplexed manner. That is, the plurality of subscriber stations can transmit an uplink signal only at a specific time designated by the optical fiber termination device, and if it violates this, the uplink signal of other subscriber stations is prevented. As such, when a specific subscriber station transmits an abnormal uplink signal, another normal subscriber station cannot normally communicate with the optical fiber terminal device. In addition, the optical power divider used in the TDM PON system is a passive element that simply divides the optical power equally by the number of ports. There is a problem in that a number of subscriber stations distributed in a range of several tens of kilometers must be investigated.

On the other hand, in order to solve such a problem, conventionally, by monitoring the difference in the reception position of the uplink signal received by the optical fiber termination device, or by analyzing the frequency of the uplink signal to block the abnormal uplink transmission.

The method of monitoring the difference in the reception position of the uplink signal is a method of monitoring the difference between the actual position of the upstream signal and the expected reception position of the uplink signal, and determining that an abnormality has occurred in the corresponding subscriber station when it exceeds a preset value. Such a method of monitoring a difference in the reception position of an uplink signal detects a gradual abnormality of a plurality of subscriber stations, but it is difficult to process a subscriber station having an irregular uplink transmission position, and detects a subscriber station having abnormally continuous uplink transmission. This has a hard disadvantage.

On the other hand, the method using the frequency analysis of the uplink signal stops the transmission of the uplink signal of the subscriber station in the optical fiber terminal device, and then transmits a pattern having a specific frequency upward from each subscriber station. Thereafter, the optical fiber terminal device checks whether the uplink signal transmission is performed at the frequency requested by the optical fiber terminal device through frequency analysis of the uplink signals received from the subscriber terminals. Such a method can detect an abnormal subscriber station not following the uplink signal transmission instruction of the optical fiber termination device, and can determine whether other subscriber stations are normally present even when there is an abnormal subscriber station for continuous uplink signal transmission. For example, in order to block an uplink signal detected by an abnormal subscriber station, an administrator is eventually dispatched to a site where an abnormal subscriber station is located, so that the abnormal subscriber station should be restored normally.

The present invention aims to solve such a problem, and aims to detect abnormal subscriber terminals and remotely block the detected abnormal subscriber terminals.

Furthermore, an object of the present invention is to prevent abnormal communication between a plurality of normal subscriber terminals by detecting abnormal subscriber terminals and remotely blocking the detected subscriber terminals.

Furthermore, an object of the present invention is to recover an abnormal subscriber station quickly so that normal operation is performed.

The foregoing technical problem is achieved by the characteristic aspects of the present invention described below. An optical transceiver for transmitting and receiving an uplink or downlink signal with a plurality of optical network units (ONUs) according to the present invention, and continuous for at least a threshold time from at least one subscriber station of the plurality of subscriber stations through the optical transceiver When the uplink signal is received, the subscriber station transmitting a continuous uplink signal is requested, and the remote node (Remote Node: RN) connected to a plurality of subscriber stations to block the uplink signal transmission of the detected subscriber station It characterized in that it comprises a control unit.

The remote controller according to an additional aspect of the present invention refers to an uplink signal received from the optical transceiver and an uplink signal detector for continuously detecting whether an uplink signal is received for a time greater than or equal to a threshold; A control signal generator for generating an electrical signal to control all the optical switches connected to the node, an all-optical converter for converting the electrical signal generated from the control signal generator into an optical signal, and a remote node through the optical transmitter and receiver. And a first wavelength division multiplexing (WDM) coupler for combining the downlink signal to be transmitted to the optical signal converted from the all-optical conversion unit and transmitting the combined optical signal to the remote node.

According to an additional aspect of the present invention, when an uplink signal is received from a subscriber station associated with an optical switch in an on state through an optical switch controller, the uplink signal detector determines that the subscriber station is a subscriber station transmitting an abnormal uplink signal. Characterized in that it comprises a detection unit.

According to a further aspect of the present invention, a remote node includes a second wavelength division multiplexing coupler for separating an optical signal converted from an all-optical conversion unit among signals coupled from the first wavelength division multiplexing coupler, and a second wavelength division multiplexing coupler separated from the second wavelength division multiplexing coupler. A photoelectric conversion unit for receiving an optical signal and converting the same into an electrical signal, and controlling all the optical switches connected to the plurality of subscriber stations with reference to the electrical signal converted from the photoelectric conversion unit in an off state, And an optical switch controller for sequentially controlling the optical switch to the on state.

According to this aspect of the present invention, when an abnormal uplink signal is detected, the uplink transmission of all subscriber stations is instructed to stop, and the remote node is controlled so that all the optical switches are turned off, and the optical switches in the off state are sequentially turned on. When the upstream signal is received from the subscriber station connected to the optical switch in the on state by controlling the remote node to be in the state, it is determined that the subscriber station is an abnormal subscriber station, thereby detecting the abnormal subscriber station, and the detected subscriber station is remote The node can block communication with the fiber termination device.

As described above, the optical fiber terminal device and method for controlling an abnormal subscriber terminal in a time division multiplexing passive optical subscriber network according to the present invention are an abnormal subscriber terminal continuously transmitting an uplink signal to the optical fiber terminal device for a time greater than or equal to a threshold. By detecting a quick and easy to block the corresponding subscriber station to the communication with the terminal device in the light beam, it is possible to prevent an error in the operation of the subscriber station that normally transmits the uplink signal by the abnormal subscriber station. In addition, it is possible to quickly detect the location of the abnormal subscriber terminal to recover the abnormal subscriber terminal is an effect that the abnormal subscriber terminal can quickly operate normally.

The foregoing and further aspects of the present invention will become more apparent through the preferred embodiments described with reference to the accompanying drawings. Hereinafter, the present invention will be described in detail so that those skilled in the art can easily understand and reproduce the present invention through these embodiments.

1 is a diagram illustrating the configuration of a TDM PON.

As shown in FIG. 1, the TDM PON includes a single fiber termination device 100 and a plurality of subscriber stations 300 connected to the remote node 200. That is, the plurality of subscriber stations 300 connected to the optical fiber terminal 100 and the remote node 200 have a tree structure corresponding to 1: N. The plurality of subscriber stations 300 of the TDM PON may transmit an uplink signal to the optical fiber termination device 100 only for a time allocated to each subscriber terminal 300. The downlink signal transmitted from the optical fiber termination device 100 to the plurality of subscriber stations 300 is transmitted to all the subscriber stations 300 through the optical power divider so that no failure occurs. However, when at least one subscriber station 300 of the plurality of subscriber stations 300 transmits an uplink signal in addition to the time allocated to the subscriber station, the other subscriber station 300 cannot normally transmit the uplink signal and thus all the subscribers. There is a problem that the terminal 300 does not normally transmit the uplink signal.

 FIG. 2 is a block diagram schematically illustrating a configuration of an optical fiber terminal device for remotely controlling an abnormal subscriber station according to an embodiment of the present invention.

As shown, the optical fiber termination device 100 includes an optical transceiver 110 and a remote controller 120. The optical transceiver 110 receives an uplink signal from the plurality of subscriber stations 300 or a plurality of downlink signals to the subscriber stations 300.

The remote controller 120 determines whether the uplink signal received from the optical transceiver 110 is an abnormal uplink signal. That is, when an abnormal signal pattern is received from at least one subscriber station 300 of the plurality of subscriber stations 300, the remote controller 120 requests the detection of the subscriber station 300 that transmits the abnormal uplink signal. The remote node 200 connected to the plurality of subscriber stations 300 is controlled to block the detected uplink signal transmission of the subscriber station 300. Here, the abnormal signal pattern means that the uplink signal is continuously received for a period of time above the threshold. On the other hand, the above-mentioned remote node 200 is configured to control the abnormal operation of the subscriber terminal device 300 in response to the request of the remote control unit 120 will be described in detail below.

The remote controller 120 for controlling the remote node 200 is a remote node through an uplink signal detector 121, a control signal generator 125, an all-optical converter 127, and a first wavelength division multiplexing coupler 129. Control 200. The uplink signal detector 121 detects whether the uplink signal received from the optical transmitter 110 is an abnormal uplink signal. That is, the uplink signal detector 121 detects whether at least one of the plurality of subscriber stations 300 continuously transmits the uplink signal for a time equal to or greater than a threshold. When it is detected that the uplink signal is continuously transmitted from the specific subscriber station 300 for a time greater than or equal to the threshold value, the uplink signal detector 121 determines that there is an abnormal subscriber station 300. When the control signal generator 125 detects that there is an abnormal subscriber terminal 300 through the uplink signal detector 121, the control signal generator 125 may provide an electrical signal to control all the optical switches 230 connected to the remote node 200. Create

The all-optical converter 127 converts the electrical signal generated from the control signal generator 125 into an optical signal. That is, the all-optical converter 127 receives the electrical signal generated from the control signal generator 125 so that the control signal can be transmitted through the optical line connected between the optical fiber terminal 100 and the remote node 200. Convert to an optical signal. Such an optical signal is preferably a signal of a wavelength separate from the upward or downward wavelength used by the optical fiber termination device 100. The first wavelength division multiplexing coupler 129 combines the downlink signal to be transmitted to the remote node 200 through the optical transceiver 110 and the optical signal converted from the all-optical converter 127 and transmits it to the remote node 200. do. Accordingly, the remote node 200 controls all the optical switches 230 with reference to the signals received from the first wavelength division multiplexing coupler 129 of the optical path termination device 100 as shown in FIG. 3.

3 is a block diagram illustrating a configuration of a remote node 200 for controlling an abnormal subscriber terminal device 300 according to an embodiment of the present invention.

As shown, the remote node 200 includes a second wavelength division multiplexing coupler 210, an optical power splitter 220, an optical switch 230, an optical receiver 240, and an optical switch controller 250. The second wavelength division multiplexing coupler 210 may transmit an optical signal converted from the all-optical converter 127 and a downlink signal to be transmitted to the plurality of subscriber stations 300 among the signals coupled from the first wavelength division multiplexing coupler 129. Separate. The separated downlink signal is transmitted to the optical power splitter 220, and the plurality of subscriber stations 300 receive the downlink signal transmitted from the optical power splitter 220 through the optical switch 230 connected thereto.

Meanwhile, the optical signal separated by the second wavelength division multiplexing coupler 210 is converted into an electrical signal through the photoelectric conversion unit 240. The optical switch controller 250 controls all the optical switches 230 connected to the plurality of subscriber stations 300 to the off state with reference to the electrical signal converted from the photoelectric conversion unit 240, and the optical switch in the off state 230 is sequentially controlled to the on state. As such, the remote node 200 controls the optical switch 230 to be turned on or off with reference to an optical signal among the signals received from the first wavelength division multiplexing coupler 129 through the optical switch controller 250. .

As described above, when all the optical switches 230 are controlled to the off state through the optical switch controller 250, the abnormal subscriber station detection unit 123 detects the abnormal subscriber terminal 300. When the abnormal subscriber station detection unit 123 receives an uplink signal from the subscriber station 230 associated with the optical switch 230 in the on state through the optical switch controller 250 of the remote node 200, the corresponding subscriber station ( 230 is a configuration for determining that the subscriber station 230 for transmitting an abnormal uplink signal. That is, as the abnormal uplink signal is detected, when all the optical switches 230 connected to the remote node 300 are controlled to the off state, the abnormal subscriber station detection unit 123 requests the detection of the abnormal subscriber station 300. Accordingly, the control signal generator 125 generates an electrical signal to sequentially control the optical switch 230 in the off state to the on state. Thereafter, the all-optical converter 127 converts the electrical signal generated from the control signal generator 125 into an optical signal, and the converted optical signal is transmitted to the remote node 200 through the first wavelength division multiplexing coupler 129. Is sent to. Thereafter, the remote node 200 separates the signal received from the first wavelength division multiplexing coupler 129 through the second wavelength division multiplexing coupler 210, and the separated optical signal is electrically transferred through the photoelectric conversion unit 240. Converts to a negative signal. Thereafter, the optical switch controller 250 sequentially controls the optical switch 230 in the off state to the on state according to the converted signal. The optical switch controller 250 may sequentially control the optical switch 230 to the on state according to previously stored information.

Thereafter, the abnormal subscriber station detection unit 123 checks whether an uplink signal is received from the subscriber station 300 connected to the optical switch 230 which is sequentially turned on through the optical transceiver 110. When it is checked that the uplink signal is received through the optical transceiver 110, the abnormal subscriber station detection unit 123 determines that the subscriber station 300 that transmits the uplink signal is the abnormal subscriber station 300, and the corresponding subscriber. The remote node 200 is controlled to turn off the optical switch 230 connected to the terminal 300. Accordingly, the optical switch controller 250 controls the optical switch 230 in the off state. When the operation state check of all the subscriber stations 300 is completed, the abnormal subscriber station detection unit 123 may perform the operation of the subscriber station 300 other than the subscriber station 300 which has transmitted the abnormal uplink signal to resume the remote node 200. To control. Accordingly, the optical fiber terminal device 100 detects the subscriber terminal 300 that transmits an abnormal uplink signal and controls the operation so that the other subscriber terminal 300 can normally communicate with the optical fiber terminal device 100. It becomes possible.

Hereinafter, a method of remotely controlling the abnormal subscriber station 300 by the optical fiber terminal device 100 will be described in detail with reference to FIGS. 4 and 5.

4 is a flowchart illustrating a method of remotely controlling an abnormal subscriber station according to an embodiment of the present invention.

As shown, the optical fiber termination device 100 receives a plurality of subscriber stations 300 through the remote node upstream signal. That is, the plurality of subscriber stations 300 transmits an uplink signal to the optical fiber termination device 100 at the time allocated to the subscriber station 300. Accordingly, the optical fiber termination apparatus 100 checks whether an uplink signal is normally received from the plurality of subscriber stations 300 (S100). When the uplink signal is continuously received from the at least one subscriber station 300 among the plurality of subscriber stations 300 for a time equal to or greater than a threshold value, the optical fiber termination device 100 determines that the corresponding subscriber station 300 is abnormal. Subsequently, the optical fiber termination apparatus 100 requests the remote node 200 to which the plurality of subscriber stations 300 are connected as shown in FIG. 5 to stop the uplink signal transmission of the plurality of subscriber stations 300. When uplink signal transmission of the plurality of subscriber stations 300 is stopped, the optical fiber termination apparatus 100 sequentially operates the plurality of stationary subscriber terminals 300 to detect the subscriber station 300 transmitting abnormal abnormal uplink signals. Then, the remote node 200 is controlled to block the detected uplink signal transmission of the subscriber station 300 (S200).

5 is a flowchart illustrating a method of detecting and blocking an abnormal subscriber station according to an embodiment of the present invention.

As the uplink signal is continuously received from the specific subscriber station 300 for a threshold time or more, the optical fiber termination apparatus 100 requests the remote node 200 not to transmit a plurality of uplink signals to the subscriber station 300. . Accordingly, the remote node 200 controls the optical switch connected to the plurality of subscriber station 300 in the off state (S210). When all the optical switches are controlled to the off state, the optical fiber terminal device 100 controls the remote node 200 to be turned on (S220). Accordingly, the remote node 200 sequentially turns on the optical switch in the off state. When the optical switch in the off state is turned on through the remote node 200, the optical fiber terminal 100 checks whether an uplink signal is received from the subscriber terminal 300 connected to the optical switch in the on state (S230). . When the uplink signal is received from the subscriber station 300 connected to the optical switch in the on state, the optical fiber terminal 100 determines that the corresponding subscriber station 300 is an abnormal subscriber station 300. Thereafter, the optical fiber terminal device 100 requests the remote node 200 to block the operation of the corresponding subscriber terminal 300, and the remote node 200 controls the optical switch of the corresponding subscriber terminal 300 to the off state. (S240). In this case, it is preferable that the optical fiber termination device 100 checks whether an uplink signal is received from all subscriber stations 300 connected to the optical switch in the on state.

When the operation status check of all the subscriber stations 300 is completed, the optical fiber terminal device 100 is configured to resume operation of the subscriber stations 300 other than the subscriber station 300 that has transmitted an abnormal uplink signal. (S300). Accordingly, the optical fiber terminal device 100 quickly detects the subscriber terminal 300 that transmits an abnormal uplink signal and controls the operation so that the other subscriber terminal 300 can normally communicate with the optical fiber terminal device 100. Will be.

So far I looked at the center of the preferred embodiment for the present invention.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a block diagram showing a configuration of a TDM PON,

2 is a block diagram schematically illustrating a configuration of an optical fiber terminal device for remotely controlling an abnormal subscriber terminal according to an embodiment of the present invention;

3 is a block diagram illustrating a configuration of a remote node 200 for controlling an abnormal subscriber terminal device 300 according to an embodiment of the present invention.

4 is a flowchart illustrating a method of remotely controlling an abnormal subscriber station according to an embodiment of the present invention;

5 is a flowchart illustrating a method of detecting and blocking an abnormal subscriber station according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: optical fiber terminal 110: optical transceiver

120: remote control 121: uplink signal detector

123: abnormal subscriber station detection unit 125: control signal generation unit

127: all-optical conversion unit 129: first wavelength division multiplexing coupler

200: remote node 210: second wavelength division multiplexing coupler

220: optical power divider 230: optical switch

240: photoelectric conversion unit 250: optical switch control unit

300: subscriber terminal

Claims (6)

An optical transceiver for transmitting and receiving an uplink or downlink signal with a plurality of optical network units (ONUs); When an abnormal signal pattern is received from at least one subscriber station among the plurality of subscriber stations through the optical transceiver, request detection of a subscriber station transmitting the abnormal signal pattern, and transmit uplink signal transmission of the detected subscriber station. A remote control unit controlling a remote node (RN) connected to the plurality of subscriber stations to block; The optical fiber terminal device capable of remote control of an abnormal subscriber terminal, comprising: a. The method of claim 1, wherein the remote control: An uplink signal detector for detecting whether an uplink signal is continuously received for a time equal to or greater than a threshold value by referring to an abnormal signal pattern received from the optical transceiver; A control signal generator for generating an electrical signal to control all optical switches connected to the remote node when detected through the uplink signal detector; An all-optical converter converting the electrical signal generated from the control signal generator into an optical signal; A first wavelength division multiplexing (WDM) coupler for combining a downlink signal to be transmitted to the remote node through the optical transmission receiver and an optical signal converted from the all-optical conversion unit and transmitting the combined optical signal to the remote node; The optical fiber terminal device capable of remote control of an abnormal subscriber terminal, comprising: a. The method of claim 2, The remote node A second wavelength division multiplexing coupler for separating the optical signal converted from the all-optical conversion unit among the signals coupled from the first wavelength division multiplexing coupler; A photoelectric conversion unit which receives the optical signal separated from the second wavelength division multiplexing coupler and converts the optical signal into an electrical signal; An optical switch controller for controlling all optical switches connected to the plurality of subscriber terminals in an off state with reference to the electrical signal converted from the photoelectric conversion unit, and sequentially controlling the optical switches in the off state in an on state; The optical fiber terminal device capable of remote control of an abnormal subscriber terminal, comprising: a. The method of claim 3, wherein the uplink signal detector comprises: An abnormal subscriber station detection unit determining that the corresponding subscriber station is a subscriber station transmitting an abnormal uplink signal when an uplink signal is received from a subscriber station associated with the optical switch in an on state through the optical switch controller; The optical fiber terminal device capable of remote control of an abnormal subscriber terminal, comprising: a. Checking whether an uplink signal is normally received from a plurality of subscriber stations; If the uplink signal is continuously received from a particular subscriber station for a time period equal to or greater than a threshold value, the subscriber station transmitting an abnormal uplink signal by stopping the uplink signal transmission of the plurality of subscriber stations and sequentially operating the plurality of suspended subscriber stations. Controlling remote nodes coupled to the plurality of subscriber stations to detect and block; Controlling to perform uplink signal transmission of all subscriber stations other than the abnormal subscriber station; Remote control method of the subscriber station abnormal in the optical fiber termination device comprising a. 6. The method of claim 5, wherein controlling remote nodes connected to the plurality of subscriber stations to detect and block the subscriber stations transmitting the abnormal uplink signal includes: Controlling all optical switches associated with the plurality of subscriber stations to an off state; Sequentially controlling the optical switch in the off state to an on state; Checking whether an uplink signal is received from a subscriber station associated with the optical switch in the on state; If an uplink signal is received from a subscriber station associated with the optical switch in the on state, controlling the optical switch of the subscriber station in the off state; Remote control method of the subscriber station abnormal in the optical fiber termination device comprising a.

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