KR102034268B1 - WDM-based PON Reach Extender Providing Redundant Line - Google Patents

Abstract

The present invention is a WDM-based PON distance expansion device that provides a reserve line, more specifically, having a reserve line, even if an error occurs in the optical line termination device (OLT) located in the national office to secure a bypass path through the reserve line to the subscriber A WDM-based PON distance extension device for maintaining a connection.

Description

WDM-based PON Reach Extender Providing Redundant Line}

The present invention is a WDM-based PON distance expansion device that provides a reserve line, more specifically, having a reserve line, even if an error occurs in the optical line termination device (OLT) located in the national office to secure a bypass path through the reserve line to the subscriber A WDM-based PON distance extension device for maintaining a connection.

Passive Optical Networks (PON) have become the core of the implementation of the FTTH environment and the implementation of Giga-bit Ethernet, and currently occupy most of the domestic subscriber network network.

In PON, the same data goes down from the optical line terminal (OLT) to the optical network terminal (ONT) / optical network unit (ONU) in the down direction, and the burst that raises data at the time allocated from each ONT / ONU in the upward direction. Operate in Burst Mode.

In the case of a typical PON, a light distance is reduced because a passive element, an optical node (Remote Node or Splitter), is used, and thus a transmission distance limit of about 20 km exists. The optical branch is used passively in the FTTH (Fiber To The Home) environment because it does not require a separate power supply because it is a passive device, and can increase subscribers at a simple and low cost.

In order to overcome this distance limitation, Reach Extender technology has been proposed. The distance extension device is a technology that extends the link budget by amplifying or remodulating a signal using an active element in the middle. This extends the transmission distance and number of branches in existing optical networks.

Although different from company to company, one PON OLT line card typically houses eight 10G OLT PON optical modules, while the OLT accommodates ten OLT line cards. In addition, the optical line can be branched into 32 lines by an optical branch, which theoretically accommodates 2,560 subscribers per OLT system. The OLT is connected to a server, IDC, etc. through a network to enable subscriber access.

At this time, there is a problem that the communication of the entire subscriber is disconnected in case of sudden OLT failure or emergency occurs.

An object of the present invention is to provide a WDM-based PON distance extension device that maintains the connection by securing a detour path through the reserve line even when an error occurs in the optical line termination device (OLT) located in the national office with a reserve line. do.

In order to solve the above problems, the present invention, as a central base station terminal (COT) of the WDM-based PON distance expansion apparatus for providing a reserve circuit, a reserve circuit module connected to the reserve circuit; One or more ONU optical modules for receiving an optical signal transmitted from each of the ports of the optical line terminator and converting the optical signal into an electrical signal; Two or more COT converters converting the electrical signals of the preliminary circuit module and the ONU optical modules into a WDM signal and outputting the WDM signal; And a COT control unit for controlling and monitoring the operation and communication of the central base station terminal (COT).

In order to solve the above problems, the present invention, as a remote terminal (RT) of the WDM-based PON distance extension device for providing a preliminary line, two or more RT conversion unit for receiving two or more WDM signals converted into electrical signals and output ; An interface module for retiming the electrical signals output from the RT converters, and determining a port to be output based on whether LOS of the electrical signals output from the RT converters is output; One or more PON optical modules for converting an electrical signal output from the interface module into an optical signal and outputting the optical signal; And an RT controller for controlling and monitoring the operation and communication of the remote terminal (RT).

In the present invention, one of the two or more RT conversion unit receives a signal through the preliminary line, except for this one or more RT conversion unit may receive a signal through each of the ports of the optical line termination device.

In the present invention, the interface module, the OLT module for receiving a signal through the preliminary line from the RT converter to distribute the signal to the PON optical modules of the remote terminal; At least one retiming interface module for receiving a signal through each of the ports of the optical line terminator from the RT converters and retiming the signal to the PON optical modules of the remote terminal; And an interface module control module for controlling the operation of the interface module.

In the present invention, the interface module control module, when the signal loss is not detected through the RT control unit, outputs a signal through each of the ports of the optical line terminator through the retiming interface module, the RT control unit When the loss of the signal is detected through, through the OLT module can output the signal through the preliminary line.

In the present invention, the interface module may further include a LOS detection module for detecting whether the signal received from the RT converter is lost.

In the present invention, when no signal loss is detected through the LOS sensing module or the RT controller, the interface module control module outputs a signal through each of the ports of the optical line terminator through the retiming interface modules. When the signal loss is detected through the LOS sensing module or the RT controller, the signal through the preliminary line may be output through the OLT module.

In order to solve the above problems, the present invention is a WDM-based PON distance extension device for providing a preliminary line, the distance extension device is a central base station terminal (COT), wavelength division multiplexer (WDM MUX), wavelength division multiplexer (WDM DeMUX) and a remote terminal (RT), wherein the central base station terminal (COT), a reserve circuit module connected to the reserve circuit; One or more ONU optical modules for receiving an optical signal transmitted from each of the ports of the optical line terminator and converting the optical signal into an electrical signal; Two or more COT converters converting the electrical signals of the preliminary circuit module and the ONU optical modules into a WDM signal and outputting the WDM signal; And a COT control unit for controlling and monitoring the operation and communication of the central base station terminal (COT), wherein the remote terminal (RT) includes two or more RT conversions for receiving two or more WDM signals and converting them into electrical signals and outputting them reed mace; An interface module for retiming the electrical signals output from the RT converters and determining a port to be output based on whether the LOS of the electrical signals output from the RT converters is output; One or more PON optical modules for converting an electrical signal output from the interface module into an optical signal and outputting the optical signal; And an RT control unit for controlling and monitoring the operation and communication of the remote terminal (RT).

In the present invention, one of the two or more RT conversion unit receives a signal through a preliminary line, except for this one or more RT conversion unit receives a signal through each of the ports of the optical line termination device, the interface module, An OLT module which receives a signal through the preliminary line from the RT converter and distributes the signal to the PON optical modules of the remote terminal; At least one retiming interface module for receiving a signal through each of the ports of the optical line terminator from the RT converters and retiming the signal to the PON optical modules of the remote terminal; And an interface module control module for controlling the operation of the interface module.

According to an embodiment of the present invention, an active module of a remote terminal in a passive optical communication network can exert an effect of extending the transmission distance of the communication network.

According to an embodiment of the present invention, it is possible to reduce an optical line through wavelength division multiplexing and to have an effect of accommodating a large number of subscribers per optical line.

According to an embodiment of the present invention by providing a preliminary line bypassing the optical line termination device, it is possible to achieve the effect of continuously maintaining the connection of the subscriber even when a failure or an emergency of the optical line termination device occurs.

1 is a view schematically showing the structure of a PON according to an embodiment of the present invention.
2 is a diagram schematically illustrating a structure of a PON using WDM according to an embodiment of the present invention.
3 is a block diagram schematically showing the inside of a central base station terminal (COT) according to an embodiment of the present invention.
4 is a block diagram schematically showing the inside of a remote terminal RT according to an embodiment of the present invention.
5 is a block diagram schematically illustrating the inside of an interface module according to an embodiment of the present invention.
6 is a diagram schematically showing an example of an operation of an interface module according to an embodiment of the present invention.
7 is a diagram schematically showing an example of an operation of an interface module according to an embodiment of the present invention.

In the following, various embodiments and / or aspects are now disclosed with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. However, it will also be appreciated by one of ordinary skill in the art that this aspect (s) may be practiced without these specific details. The following description and the annexed drawings set forth in detail certain illustrative aspects of the one or more aspects. However, these aspects are exemplary and some of the various methods in the principles of the various aspects may be used and the descriptions described are intended to include all such aspects and their equivalents.

Moreover, various aspects and features will be presented by a system that may include a number of devices, components, and / or modules, and the like. The various systems may include additional devices, components, and / or modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in connection with the drawings. It must be understood and recognized.

As used herein, “an embodiment”, “an example”, “aspect”, “an example”, etc., may not be construed as having any aspect or design described being better or advantageous than other aspects or designs. . The terms '~ part', 'component', 'module', 'system', 'interface', etc. used generally mean a computer-related entity, for example, hardware, hardware And a combination of software and software.

In addition, the terms "comprises" and / or "comprising" mean that such features and / or components are present, but exclude the presence or addition of one or more other features, components, and / or groups thereof. It should be understood that it does not.

In addition, terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

In addition, in the embodiments of the present invention, unless otherwise defined, all terms used herein including technical or scientific terms are generally understood by those skilled in the art to which the present invention belongs. Has the same meaning as Terms such as those defined in the commonly used dictionaries should be interpreted as having meanings consistent with the meanings in the context of the related art, and ideally or excessively formal meanings, unless explicitly defined in the embodiments of the present invention. Not interpreted as

1 is a view schematically showing the structure of a PON according to an embodiment of the present invention.

Referring to FIG. 1, a passive optical network (PON) according to an embodiment of the present invention includes an optical line terminal device (Optical Line Terminal) connected to a server and / or an IDC 10 through the Internet 20. OLT) 100, an optical distribution network 40 for transmitting a PON signal transmitted from the OLT 100, and an optical distribution unit 50 for distributing optical signals in the optical distribution network. Optical network terminal (ONT) 60-1 at the end of the PON to provide a service interface to a single subscriber and DSL, coaxial cable or An optical network unit (hereinafter referred to as ONU) 60-2 that provides a converged interface such as Ethernet.

The OLT 100 is an optical termination device of a provider side of a PON, and performs a control function, a switch function, and a service network interface function of the PON. The OLT 100 is connected to the server and / or IDC 10 via the Internet 20 to allow subscribers of the PON to access the server and / or IDC 10.

The optical distribution network 40 transmits a signal transmitted from the OLT 500 to the subscriber. The optical distribution network 40 has a transmission distance of about 20 km.

The ODU 50 distributes the signal in the optical distribution network 40. The ODU 50 is composed of an optical splitter, which is a passive element, and can distribute signals to up to 32 ports. The optical communication network distributed through the ODU 50 is connected to a plurality of ONTs 60-1 and / or ONUs 60-2.

The ONT 60-1 is an optical termination device at the subscriber side of the PON, and includes an apparatus connected to the subscriber's device such as an optical modem to receive an optical signal from the PON and transmit an electrical signal to the subscriber's device.

The ONU 60-2 is an optical termination device on the subscriber side of the PON. The ONU 60-2 receives an optical signal from the PON, converts it into an electrical signal, and is connected to a LAN connected to a plurality of subscribers to provide a service.

In the case of such a PON, the transmission distance is only about 20 km, and many ONTs and ONUs are connected to one OLT in a single-to-multipoint connection method. Failure may occur.

2 is a diagram schematically illustrating a structure of a PON using WDM according to an embodiment of the present invention.

Referring to FIG. 2, a passive optical network (PON) using wavelength division multiplexing (WDM) according to an embodiment of the present invention is connected to a server or IDC 10 through the Internet 20.1. Optical Line Terminal (OLT) 100, a central office terminal (COT) 200 for receiving a PON signal from the OLT 100 and converting it into a WDM signal, and the WDM signal WDM Multiplexer (WDM MUX) 300 for multiplexing, trunk trunk network 30 for transmitting multiplexed WDM signals, WDM Demultiplexer (WDM DeMUX) for distributing multiplexed WDM signals 400, a remote terminal 500 for converting the received WDM signal into a PON signal, an optical distribution network 40 for transmitting the PON signal converted from the RT 500, and the distribution. Optical Distribution Unit (ODU) for distributing optical signals in networks 50) an optical network terminal (ONT) 60-1 located between the ends of the PON to provide a service interface to one subscriber and a DSL, coaxial cable or An optical network unit (hereinafter referred to as ONU) 60-2 that provides a converged interface such as Ethernet.

Like the OLT 100 of FIG. 1, the OLT 100 is an optical termination device of a provider side of a PON, and performs a control function, a switch function, and a service network interface function of the PON. The OLT 100 is connected to the server and / or IDC 10 via the Internet 20.1 to allow subscribers of the PON to access the server or IDC 10.

The COT 200 is a terminal located in the operator's central base station and is required for signal multiplexing in the PON. In a passive optical communication network using wavelength division multiplexing as shown in FIG. 2, the COT 200 receives a signal from the OLT 100 and converts the signal into a WDM signal. In this case, the COT 200 may not only access the server and / or IDC 10 through the OLT 100 connected to the Internet 20.1, but also connect the OLT 100 through the Internet 20.2 through a preliminary circuit. It is possible to connect with the server and / or IDC (10) without going through).

The WDM MUX 300 multiplexes the WDM signal converted by the COT 200. By multiplexing the signals as described above, an optical line connected to subscribers can be reduced.

The trunk relay network 30 transmits a wavelength division multiplexing signal. Although the general PON transmission distance is only about 20 km, since the above-described COT 200 and the RT 500 to be described later modulate the signal into a WDM signal and amplify and retransmit the signal, the transmission distance is increased to about 40 km. It becomes possible.

The WDM DeMUX 400 demultiplexes the signal multiplexed by the WDM MUX 300 again and distributes the signal through each port.

The RT 500 is a terminal located in a densely populated subscriber area requiring multiple circuits, and is required for demultiplexing of signals in a PON. The RT 500 receives the WDM signal distributed by the WDM DeMUX 400 and converts the WDM signal into a PON signal to provide a service to a subscriber.

The optical distribution network 40 transmits the signal converted by the RT 500 to the subscriber. The optical distribution network 40 has a transmission distance of about 20 km.

The ODU 50 distributes the signal of the optical distribution network 40. The ODU 50 is composed of an optical splitter, which is a passive element, and can distribute signals to up to 32 ports. The optical communication network distributed through the ODU 50 is connected to a plurality of ONTs 60-1 and / or ONUs 60-2.

The ONT 60-1 is an optical termination device at the subscriber side of the PON, and includes an apparatus connected to the subscriber's device such as an optical modem to receive an optical signal from the PON and transmit an electrical signal to the subscriber's device.

The ONU 60-2 is an optical termination device on the subscriber side of the PON. The ONU 60-2 receives an optical signal from the PON, converts it into an electrical signal, and is connected to a LAN connected to a plurality of subscribers to provide a service.

As described above, according to an embodiment of the present invention, the transmission distance of the PON can be extended, and the WDM can reduce the optical line and have an effect of accommodating a large number of subscribers per optical line.

3 is a block diagram schematically showing the inside of a central base station terminal (COT) according to an embodiment of the present invention.

Referring to FIG. 3, the central base station terminal (COT) 200 according to an embodiment of the present invention inputs an optical signal transmitted from each of the ports of the preliminary circuit module 210 and the optical line terminator connected to the preliminary line. One or more ONU optical modules 220.1 to 220.M for receiving and converting the signals into electrical signals, and converting the electrical signals of the preliminary circuit module 210 and the ONU optical modules 220.1 to 220.M to WDM signals for output. Two or more COT conversion units 230.1 to 230.N, and the COT control unit 240 for controlling and monitoring the operation and communication of the central base station terminal (COT) (200).

The reserve circuit module 210 transmits and receives information through a server and / or IDC 10 connected through a reserve circuit connected to a COT. Since the preliminary line is connected to the server and / or IDC 10 without passing through the OLT, it is possible to stably maintain the connection to the server and / or IDC 10 even in the event of a failure or an emergency OLT.

The ONU optical modules 220.1 to 220.M receive an optical signal output from the PON port of the OLT 200 and convert the optical signal into an electrical signal. The COT 200 includes one or more M ONU optical modules to receive an optical signal from the OLT 200.

The COT conversion units 230.1 to 230.N convert electrical signals output from the preliminary circuit module 210 and the ONU optical modules 220.1 to 220.M into WDM signals. The converted WDM signal is then input to the WDM MUX 300 and multiplexed, and then transmitted through the trunk relay network 30. To this end, the COT converters include an apparatus for generating an optical signal having a wavelength conforming to the WDM standard. The COT 200 includes two or more N COT converters to correspond one-to-one to the preliminary circuit module 210 and the M ONU optical modules 220.1 to 220.M. Therefore N must be greater than M. If the PON distance extension device according to an embodiment of the present invention has one spare line, N is preferably M + 1.

The COT control unit 240 controls and monitors the operation and communication of the COT. The COT control unit 240 controls the operations of the preliminary circuit module 210, the ONU optical modules 220.1 to 220.M, and the COT conversion units 230.1 to 230.N, and the operating and communication conditions of the modules. Monitor this to detect any abnormality or control the communication service according to the administrator's command. Preferably, the command of the administrator may be made through a Simple Network Management Protocol (SNMP) channel. Also, if an abnormality is detected, it can be reported to the manager and other devices through the SNMP channel.

4 is a block diagram schematically showing the inside of a remote terminal RT according to an embodiment of the present invention.

Referring to FIG. 4, a remote terminal (RT) 500 according to an embodiment of the present invention receives two or more RTD converters 510.1 to 510.N for receiving two or more WDM signals and converting them into electrical signals. Retiming the electrical signals output from the RT converters 510.1 to 510.N, and output ports according to whether LOS (Loss Of Signal) of the electrical signals output from the RT converters 510.1 to 510.N. Interface module 520 for determining, one or more PON optical modules (530.1 to 530.N) for converting the electrical signal output from the interface module 520 into an optical signal and outputs, and the remote terminal (RT) 500 It includes; RT control unit 540 for controlling and monitoring the operation and communication.

The RT converters 510.1 to 510.N receive a WDM signal from each port of the WDM DeMUX 400 and convert the WDM signal into an electric signal. At this time, one RT converter 510.1 of the two or more RT converters receives a signal through a preliminary line, and one or more RT converters 510.2 to 510. N except this are optical line terminators (OLT) ( It receives a signal through each of the ports of 100). At this time, the number N of the RT converter 510 is preferably equal to the number N of the COT converter 230 of FIG. 3. In addition, the wavelength of the optical signal converted by each of the RT converter 510 is preferably the same as the wavelength of the optical signal output from each of the corresponding COT converter 230.

The interface module 520 receives an electrical signal from the RT converters 510.1 to 510.N and outputs an electrical signal to the PON optical modules 530.1 to 530.N. The interface module 520 receives electrical signals from the N RT converters 510.1 to 510.N and outputs electrical signals to the M PON optical modules 530.1 to 530.M. In this case, preferably, the N RT converters 510.1 to 510.N output a signal through a preliminary line and a signal through M OLTs 100.

The interface module 520 retimes and outputs an output signal of the RT converters 510.2 to 510.N outputting a signal through the OLT 100 during normal operation, and outputs an abnormal or emergency situation to the OLT 100. In this case, when the LOS (Loss Of Signal) is generated in the signal through the OLT 100, the signal through the reserve line is output. As such, by selectively outputting a signal through the OLT 100 or a signal through a preliminary line, communication disconnection may occur in the optical distribution network through the PON optical modules 530.1 to 530.M. .

The PON optical modules 530.1 to 530.M convert electrical signals output from the interface module 520 into optical signals. The converted optical signal is transmitted to the subscriber's ONT 60-1 and / or ONU 60-2 through the optical distribution network 40 and the ODU 50. At this time, the number M of the PON optical modules 530.1 to 530.M is preferably equal to the number M of the ONU optical modules 220.1 to 220.M of FIG. 3.

The RT controller 540 controls and monitors the operation and communication of the RT. The RT controller 540 controls the operations of the RT converters 510.1 to 510.N, the interface module 520, and the PON optical modules 530.1 to 530.M, and controls operation and communication conditions of the modules. Monitors and detects abnormality or controls communication service according to administrator's command. Preferably, the command of the administrator may be made through a Simple Network Management Protocol (SNMP) channel. Also, if an abnormality is detected, it can be reported to the manager and other devices through the SNMP channel.

According to an embodiment of the present invention, when the LOS occurs, the RT controller 540 directly monitors the signal to determine the LOS, checks whether the LOS according to the input of the administrator who recognizes the LOS, or other devices detect You can check whether there is LOS by receiving a report of LOS. When the LOS generation is confirmed as described above, the RT controller 540 transmits a command to the interface module 520 to control the communication through the reserve line.

5 is a block diagram schematically illustrating the inside of an interface module according to an embodiment of the present invention.

Referring to Figure 5, the interface module 520 according to an embodiment of the present invention, the PON optical modules (530.1 to 530) of the remote terminal 500 receives a signal through the preliminary line from the RT converter (510.1). M) OLT module 521 for distributing and outputting signals to the PON optical modules of the remote terminal 500 receiving signals from the RT converters 510.2 to 530.M through respective ports of the optical line terminator. One or more retiming interface modules 522.1 to 522.M for retiming and outputting to 530.1 to 530.M; A LOS detection module 523 for detecting whether a signal received from the RT converter is lost; And an interface module control module 524 for controlling the operation of the interface module 520.

The OLT module 521 acts on behalf of the OLT 100 when a failure or emergency occurs in the OLT 100. The OLT module 521 receives a signal from the preliminary line from the RT converter 520.1 which receives a signal through the preliminary line, and replaces the OLT 100 when there is a signal loss from the OLT 100. The signal of the preliminary line is output to the PON optical modules 530.1 to 530.M.

The retiming interface modules 522.1 to 522.M receive a signal from the RT converters 510.2 to 510.N and output the signals to the PON optical modules 530.1 to 530.M. The retiming interface modules 522.1 to 522.M retime the signals of the RT converters 510.2 to 510.N according to the control of the interface module control module 524, which will be described later. 522.M) or stop the output.

The LOS sensing module 523 senses a LOS (Loss Of Signal) of an output signal of the RT converters 510.1 to 510.N. According to an embodiment of the present invention, the LOS detection module 523 determines the LOS by determining that the input signals are all zero, no bit transition of the signal, or the signal strength is less than or equal to a predetermined value for a predetermined time. Can be detected.

The interface module control module 524 controls the operation of the interface module 520. The interface module control module 524 activates the retiming interface modules 522.1 to 522.M to operate the PON signals received from the RT converters 510.2 to 510.N during normal operation. 530.1 to 530.M), and when the LOS is detected, the OLT module 521 receiving the signal through the preliminary line distributes the input signal to the PON optical modules 530.1 to 530.M. Do it. Through this method, PON subscribers can maintain the connection continuously in the event of OLT failure or emergency.

When the LOS detection module 523 detects the LOS or receives a control command from the RT controller 540, the interface module control module 524 may PON the retiming interface modules 522.1 to 522.M. The output of the signals to the optical modules (530.1 to 530.M) is interrupted, and the OLT module (521) receiving the signal through the preliminary line distributes the signals of the preliminary line to the PON optical modules (530.1 to 530.M). To be printed).

6 is a diagram schematically showing an example of an operation of an interface module according to an embodiment of the present invention.

Referring to FIG. 6, when an interface module according to an exemplary embodiment of the present invention operates normally, signals are received from the RT converters 510.2 to 510.N that output signals through the OLT 100, respectively. The interface modules 522.1 to 522.M are output to the PON optical modules 530.1 to 530.M.

That is, the optical signals output from the M OLT PON ports of the OLT 100 are converted into electrical signals by the M ONU optical modules 220.1 to 220.M of the COT 200, and then M COT conversion units ( 230.2 to 230.N) is converted into a WDM signal, and the converted WDM signal is converted into an electrical signal through M RT converting units 510.2 to 510.N, and then M L of the interface module 520 is converted. Through the timing interface modules 522.1 to 522.M, the M PON optical modules 530.1 to 530.M are converted into optical signals and transmitted to the subscriber's ONT and / or ONU to transmit signals at the PON. do.

7 is a diagram schematically showing an example of an operation of an interface module according to an embodiment of the present invention.

Referring to FIG. 7, when the interface module directly detects the LOS or when the control signal is received from the RT controller, the RT converters 510.2 to 517 output a signal through the OLT 100. PON optical modules receive the signal received by the OLT module 521 by receiving the signal from the RT converter 510.1 outputting the signal through the preliminary circuit without outputting the received signal from 510.N). And distributes it to (530.1 to 530.M).

That is, when the signal through the OLT 100 cannot be received, the signal through the preliminary line directly connected to the COT 200 passes through the preliminary line module 210 of the COT 200 in the COT conversion unit 1 (230.1). The WDM signal is converted into a WDM signal, and the converted WDM signal is converted into an electrical signal through an RT converter 1 (510.1), and after the signals are distributed in the OLT module 521 of the interface module 520, each signal is PON optical modules (530.1 to 530.M) is converted into an optical signal and transmitted to the subscriber's ONT and / or ONU to perform a signal transmission in the PON.

That is, when configuring a PON providing a spare circuit through the COT 200 and the RT 500 according to an embodiment of the present invention, in the passive optical communication network to extend the transmission distance of the communication network through the active module of the remote terminal It can be effective.

In addition, according to an embodiment of the present invention it is possible to reduce the optical line through the wavelength division multiplexing, and to have the effect of accommodating a large number of subscribers per optical line.

In addition, according to an embodiment of the present invention by having a preliminary line bypassing the optical line termination device, it is possible to achieve the effect of continuously maintaining the connection of the subscriber in the event of a failure or emergency of the optical line termination device.

Although the embodiments have been described by the limited embodiments and the drawings as described above, various modifications and variations are possible to those skilled in the art from the above description. For example, the described techniques may be performed in a different order than the described method, and / or components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different form than the described method, or other components. Or even if replaced or substituted by equivalents, an appropriate result can be achieved. Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims (9)

delete delete delete delete delete delete delete A WDM-based PON distance extender providing a spare line, the distance extender comprising a central base station terminal (COT), a wavelength division multiplexer (WDM MUX), a wavelength division demultiplexer (WDM DeMUX), and a remote terminal (RT). Including,
The central base station terminal (COT),
A reserve circuit module connected to the reserve circuit;
One or more ONU optical modules for receiving an optical signal transmitted from each of the ports of the optical line terminator and converting the optical signal into an electrical signal;
Two or more COT converters converting the electrical signals of the preliminary circuit module and the ONU optical modules into a WDM signal and outputting the WDM signal; And
And a COT control unit for controlling and monitoring the operation and communication of the central base station terminal (COT).
The reserve line may be connected to the server or IDC without passing through the OLT,
The remote terminal (RT), two or more RT converters for receiving two or more WDM signals to convert the electrical signal output;
An interface module for retiming the electrical signals output from the RT converters and determining a port to be output based on whether the LOS of the electrical signals output from the RT converters is output;
One or more PON optical modules for converting an electrical signal output from the interface module into an optical signal and outputting the optical signal; And
It includes; RT control unit for controlling and monitoring the operation and communication of the remote terminal (RT),
The interface module,
An OLT module which receives a signal through the preliminary line from the RT converter and distributes the signal to the PON optical modules of the remote terminal;
At least one retiming interface module for receiving a signal through each of the ports of the optical line terminator from the RT converters and retiming the signal to the PON optical modules of the remote terminal;
An interface module control module for controlling the operation of the interface module; And
It includes; LOS detection module for detecting whether the signal received from the RT converter loss;
The interface module control module,
If no signal loss is detected through the LOS sensing module or the RT controller, output a signal through each of the ports of the optical line terminator through the retiming interface modules,
When the signal loss is detected through the LOS detection module or the RT control unit, characterized in that for outputting a signal through a preliminary line through the OLT module, PON distance extension device.
The method according to claim 8,
One of the two or more RT conversion unit receives a signal through a preliminary line, except for this one or more RT conversion unit, characterized in that for receiving a signal through each of the ports of the optical line termination device, PON distance extension device.

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