KR100903121B1 - Optical link module of ONT/ONU with wavelength tuning function in WDM-PON, optical link system therefor, and method for wavelength tuning - Google Patents

Abstract

A link module of an optical subscriber network device (ONT / ONU) having an optical wavelength alignment function in a WDM-PON, a link module of an optical fiber termination device (OLT) supporting the same, an optical transmission / reception link system, and an optical wavelength alignment method are disclosed. The link module of ONT / ONU with optical wavelength alignment function generates link initialization information, which is logical information in a predetermined format for checking the transmission status, and sequentially specifies the output wavelength which is the wavelength to be output from the set of outputable wavelengths. When the wavelength is designated, the designated optical signal, which is an optical signal including link initialization information generated at the designated output wavelength, is transmitted, and when the response optical signal including response initialization information, which is response information about the link initialization information, is received, the sequential assignment ends. It aligns the optical wavelength of the link module of ONT / ONU by indicating.

WDM-PON, wavelength alignment, wavelength initialization

Description

Optical link module of ONT / ONU with wavelength tuning function in WDM-PON, optical link system therefor, and method for wavelength tuning }

The present invention relates to a link module, a link system, and an optical wavelength alignment method of an optical subscriber network device having an optical wavelength alignment function in a WDM-PON.

The present invention is derived from the research conducted as part of the IT new growth engine core technology development project of the Ministry of Information and Communication and the Korea Electronics and Telecommunications Research Institute. ]

Research and development on the Wavelength Division Multiplexing (WDM) -based subscriber network (VDM) to provide voice, data, and broadcast convergence services that will be greatly activated in a few years is being actively conducted worldwide.

The wavelength division multiplexing passive optical network (WDM-PON) is a method in which communication between a central base station and a subscriber is performed using respective wavelengths assigned to each subscriber. As the dedicated wavelength is used for each subscriber, security is excellent, high-capacity communication service is possible, and it is possible to apply different transmission technology, that is, different link rate and different frame format, by subscriber or service. Has an advantage.

However, WDM-PON, which has many of these advantages, uses WDM technology that multiplexes multiple wavelengths on a single optical fiber, and thus requires various different light sources as many as the number of subscribers branched by a remote node. Difficulties in the production, installation and management of different light sources are recognized as a major problem in the commercialization of WDM-PON.

In order to solve this problem, a method of using a variable light source capable of selectively changing wavelength through electric control has been actively studied.

In addition, the Optical Network Terminal / Optical Network Unit (ONT / ONU) connected to the end of WDM-PON automatically installs the optical fiber termination device without user intervention when connecting to the network to facilitate installation and reduce installation costs. It should be aligned with the wavelength assigned by (Optical Line Terminal: OLT). The wavelength assigned to the optical subscriber network device is determined by the pass wavelength of the connected arrayed waveguide grating (AWG).

Therefore, ONU / ONT equipped with a variable light source, especially the link module of ONT / ONU, must support a series of initialization functions to automatically align to the fixed wavelength allocated by the link module of the OLT during initial network connection.

Among the initialization methods for such an initialization function, a method of determining the wavelength of the link module of the ONT / ONU based on the optical signal transmitted from the OLT to the ONT is most preferred. In this case, the optical transmitter used in the link module of ONT / ONU cannot use the independent light source that is self-oscillating, and uses the light source locking or reflection type light source using a separate seed light source provided by OLT. Done.

In case of using Seed light source, input wavelength is used so no additional wavelength initialization function is required. However, this approach only applies to injection locking based FP-LDs or reflective semicondutor optical amplifiers (RSOAs) using locking or reflection mechanisms. This is possible and not applicable to tunable light sources having a general control interface. In addition, since the method using the seed light source does not use a self-oscillating independent light source, the optical quality of the output light of the ONT / ONU, in particular, the link module of the ONT / ONU is dependent on the input seed optical signal, thereby developing a modular system. This difficult, due to the polarization mode dispersion (Parization Mode Dispersion), which is one of the color dispersion and time delay phenomenon, there is a problem that long distance and high speed transmission is difficult.

The technical problem to be achieved in the present invention, WDM-PON using a variable wavelength light source, ONT / ONU link module having an optical wavelength alignment function automatically without the user or installer intervention, OLT link module that supports them, including these To provide a link system and a wavelength alignment method.

In order to achieve the above technical problem, an embodiment of a link module of an optical network terminal (Optical Network Terminal / Optical Network Unit) having an optical wavelength alignment function according to the present invention is a logical form of a predetermined format for checking the transmission status. An initialization information generation unit for generating link initialization information as information; A wavelength control unit that sequentially specifies an output wavelength that is a wavelength to be output from a set of outputable wavelengths; An optical transmitter for transmitting a designated optical signal which is an optical signal including the generated link initialization information at the designated output wavelength every time the output wavelength is designated by the wavelength controller; And a wavelength selecting unit for instructing termination of the sequential designation in the wavelength controller when receiving a response optical signal including response initialization information which is response information about the link initialization information.

In order to achieve the above technical problem, an embodiment of a link module of an optical line terminal according to the present invention is an optical receiver capable of receiving only an assigned wavelength optical signal, which is an optical signal of a pre-assigned wavelength. ; A response information generator for generating response initialization information, which is response information to the link initialization information, if the received wavelength-signal optical signal includes link initialization information that is logical information in a predetermined format for transmission state checking; And an optical transmitter for transmitting a response optical signal, which is an optical signal including the generated response initialization information.

In order to achieve the above technical problem, an embodiment of a link system having an optical wavelength alignment function according to the present invention is to generate link initialization information, which is logical information in a predetermined format for checking transmission status, and to output a set of wavelengths. Sequentially designates an output wavelength that is a wavelength to be outputted by the ACC, and transmits a designated optical signal that is an optical signal including the generated link initialization information at the designated output wavelength every time the output wavelength is specified, and responds to the link initialization information. A link module of the optical subscriber network device for terminating the sequential designation upon receiving a response optical signal including response response initialization information; And receiving only an assigned wavelength optical signal that is an optical signal of a pre-assigned wavelength among the designated optical signals, and generating the response initialization information when the received assigned wavelength optical signal includes the link initialization information, and generating the generated response initialization. And a link module of an optical line termination device for transmitting the response optical signal including information to the link module of the optical subscriber network device.

Another embodiment of the optical wavelength alignment method according to the present invention in a link module of an optical subscriber network device for achieving the above technical problem comprises the steps of: generating link initialization information which is logical information in a predetermined format for transmission status checking; Sequentially designating an output wavelength that is a wavelength to be output from a set of outputable wavelengths; Transmitting a designated optical signal which is an optical signal including the generated link initialization information at the designated output wavelength every time the output wavelength is designated; And terminating the sequential designation when receiving a response optical signal including response initialization information that is response information about the link initialization information.

In order to achieve the above technical problem, another embodiment of the optical wavelength alignment method according to the present invention in the link module of the optical line termination device in the WDM-PON, the step of receiving only the assigned wavelength optical signal which is an optical signal of a pre-assigned wavelength ; Generating the response initialization information that is response information to the link initialization information if the received allocated wavelength optical signal includes link initialization information that is logical information in a predetermined format for transmission status checking; And transmitting a response optical signal which is an optical signal including the generated response initialization information.

Another embodiment of an optical wavelength alignment method according to the present invention in a link system including a first link module of an optical subscriber network device and a second link module of an optical line termination device for achieving the above technical problem is the first link module. Generating link initialization information which is logical information in a predetermined format for the transmission status check in the link module; Sequentially specifying an output wavelength that is a wavelength to be output in the set of wavelengths output from the first link module; Transmitting, by the first link module, a designated optical signal that is an optical signal including the generated link initialization information at the designated output wavelength every time the output wavelength is designated; Receiving only an assigned wavelength optical signal, which is an optical signal of a pre-assigned wavelength, among the designated optical signals by the second link module; Generating, by the second link module, response initialization information that is response information to the link initialization information if the received allocated wavelength optical signal includes the link initialization information; Transmitting, by the second link module, a response optical signal that is an optical signal including the generated response initialization information; And terminating the sequential designation when the first link module receives the response optical signal.

This provides WT-PON's link module of ONT / ONU with automatic wavelength alignment function without user or installer intervention, OLT's link module, optical transmit / receive link system and optical wavelength alignment method.

According to the present invention, in a WDM-PON network including an ONT / ONU link module equipped with a wavelength variable light source, communication is possible by automatically initializing the optical wavelength of the link module of the ONT / ONU without user or installer intervention. . The user can automate the installation, management and operation of ONT / ONU through automatic initialization. In addition, utilizing the link initialization method of commercial Ethernet in the manner used in the present invention can be easily developed and implemented at low cost.

Hereinafter, a link module of ONT / ONU having an optical wavelength alignment function in the WDM-PON according to the present invention, a link module of the OLT, a link system, and an optical wavelength alignment method supporting the same will be described in detail with reference to the accompanying drawings.

1 is a view showing a structure on a WDM-PON of a link system having an optical wavelength alignment function according to the present invention.

Referring to FIG. 1, the WDM-PON is located in the subscriber's home or Curb, and is located in the ONT / ONU 100 connecting the subscriber devices and the central office to connect the subscriber traffic to the upper network. The multiplexer 133, the demultiplexer 135, and the AWG based router for connecting the link module 110 of the ONT / ONU 100 and the link module 140 of the OLT 130 for each wavelength. 123 and an optical fiber, a WDM filter 121 for transmitting and receiving an optical signal for each wavelength located on the ONT / ONU 100 side, and a circulator 131 located on the OLT 130 side.

Here, the link modules 110 and 140 are located on the ONT / ONU 100 side or the OLT 130 side on the WDM-PON, and have a specific transmission wavelength and a reception wavelength within the entire band of this network. One physical or logical unit that can transmit and receive. Usually, one link module is located in one ONT / ONU, and a plurality of link modules may be located in one OLT for the connected ONT / ONU.

The multiplexer 133 located in the OLT 130 multiplexes optical signals of different wavelengths output from the link modules 140 of the OLT to an optical fiber connected to an AWG-based router 123 which is a remote node. To pass. The AWG-based router 123, which is a remote node, demultiplexes the optical signal input from the OLT 130 for each wavelength and inputs the optical signal connected to the ONT / ONU 100 of each subscriber, and the ONT / ONU 100 of each subscriber. Multiplex the optical signal input from the output to the optical fiber connected to the OLT (130). The demultiplexer 135 of the OLT 130 demultiplexes the optical signal input by being multiplexed from the AWG based router 123 for each wavelength and transmits the demultiplexer 135 to the link module 140 of the OLT. Therefore, the link module 140 of the OLT and the link module 110 of the ONT / ONU are connected in a point-to-point structure through independent wavelengths.

Accordingly, a point-to-point structure is physically or at least logically formed between the link module 110 of the ONT / ONU and the link module 140 of the OLT on the WDM-PON of FIG. 1, which will be represented as a link system by FIG. 2. Can be.

2 is a diagram illustrating an embodiment of a link system having an optical wavelength alignment function according to the present invention.

Referring to FIG. 2, the link system having the wavelength alignment function according to the present invention has a point-to-point structure between the link module 110 of the ONT / ONU and the link module 140 of the OLT. Each component of FIG. 2 and the corresponding steps in FIGS. 5 and 6 will be described together.

5 is a flowchart illustrating an embodiment of an optical wavelength alignment method of a link module of an ONT / ONU according to the present invention. The optical wavelength alignment method illustrated in FIG. 5 may be performed by the link module 110 of the ONT / ONU illustrated in FIG. 2.

6 is a flow chart showing the flow of one embodiment of the optical wavelength alignment method in the link module of the OLT according to the present invention. The optical wavelength alignment method illustrated in FIG. 6 may be performed by the link module 140 of the OLT illustrated in FIG. 2.

Each link module 110 and 140 includes an optical transmitter 115 and 145 for converting an electrical signal into an optical signal and transmitting the optical signal to an optical fiber, and an optical receiver 117 and 141 for converting an optical signal input from the optical fiber into an electrical signal. Doing.

The optical transmitter 115 of the link module 110 of the ONT / ONU should have a variable wavelength optical transmitter, and the optical transmitter 145 of the link module 140 of the OLT transmits an optical signal having a fixed wavelength. Will mount.

The link module 110 of the ONT / ONU includes an initialization information generator 111, a wavelength controller 113, an optical transmitter 115, an optical receiver 117, and a wavelength selector 119.

In order to perform step 510, the initialization information generation unit 111 generates link initialization information that is logical information in a predetermined format for checking a transmission state. (S510) The initialization information generation unit 111 is a higher layer described later. It can be mounted on a protocol unit.

In this case, the logical information in a predetermined format for checking the transmission status refers to a frame or a message on a pre-promised protocol for confirming transmission conditions or transmission and reception for securing a stable transmission path. This may be a frame or message format defined in Auto Negotiation of 1000Base-X PCS / PMA specified in IEEE 802.3z or Auto Discovery of EPON MAC specified in IEEE 802.3ah.

Therefore, the link initialization information may be a first auto-negotiation message which is a message for performing an auto-negotiation function in the point-to-point environment between the ONT 100 and the OLT 130. When the optical receiver 117 of the link module of the ONT / ONU receives the response optical signal, the response initialization information, which is response information about the link initialization information included in the response optical signal, is also based on the auto-negotiation. It may be a second auto-negotiation message that is a response message to.

In addition, the link initialization information may be a first auto discovery message which is a message for performing an auto discovery function in a point-to-multipoint environment between the ONT 100 and the OLT 130. When the optical receiver 117 of the link module of the ONT / ONU receives the response optical signal, the response initialization information, which is response information about the link initialization information included in the response optical signal, is also based on the automatic discovery. It may be a second auto-discovery message that is a response message to.

To perform step 520 after step 510, the wavelength controller 113 outputs at {λ ₁ , λ ₂ , ..., λ _N } which is a set of wavelengths that the link module 110 of the ONT / ONU can output. The output wavelength λ _k , which is the wavelength to be specified, is sequentially designated (S520).

If the wavelength controller 113 instructs the wavelength selection unit 119 to finish the sequential designation within a predetermined time after designating the output wavelength λ _k , the sequential designation is terminated and the output wavelength λ _k is designated. If the case in which the wavelength selection unit 119 instructs to finish the sequential designation within a predetermined time does not occur, it is possible to designate λ _{k + 1} , which is the next output wavelength of the designated output wavelength, among the set of outputable wavelengths. . I.e. 520 steps may be carried out via the following directives specify the output wavelength of the output wavelength λ _k is given output wavelength λ _k do not occur if the instruction to terminate the sequence specified within the time specified, then binary appointed.

Herein, the time determined after designating the output wavelength means the time taken for the stable generation of the designated optical signal of the output wavelength λ _k by the optical transmitter 115 of the link module of the ONT / ONU after the output wavelength is designated. This may be determined by considering an optical stabilization time (OST) and a registration time (RT) indicating a link establishment time expected after generating a stable designated optical signal. That is, at least the predetermined time should be greater than or equal to the time when the OST elapses (OSTO), it is preferable to set larger than the time (RT) Registration Time Out (RTO).

The wavelength controller 113 includes an output wavelength value designator for sequentially specifying an output wavelength value and a control current generator for generating a control current corresponding to the value of the designated output wavelength when the output wavelength value designator is specified. Can be configured. That is, step 520 may include sequentially specifying an output wavelength value in the output wavelength designation unit and generating a control current corresponding to the value of the designated output wavelength in the control current generation unit in the designation. Can be.

In this case, the wavelength control unit 113 considers that the optical transmission unit 115 of the ONT / ONU link module includes an external resonant laser as a wavelength variable laser which is a wavelength variable light source. When receiving the control current generated by the current generation unit includes an external cavity laser (External Cavity Laser) for transmitting a designated optical signal corresponding to the control current.

When the external resonant laser is included, the wavelength controller 113 includes a look up table having a relationship between control current values capable of generating an optical signal of each wavelength for each wavelength of the set of outputable wavelengths. The control current generation unit may further generate a control current corresponding to the value λ _k of the designated output wavelength based on the lookup table.

In order to perform step 530 after step 520, the optical transmitter 115 transmits a designated optical signal including an optical signal including link initialization information to the designated output wavelength every time the output wavelength is specified by the wavelength controller 113. The optical transmitter 115 should be equipped with a wavelength tunable optical transmitter, and the wavelength tunable optical transmitter may be equipped with a wavelength tunable light source capable of changing the output wavelength through external control. The tunable light source may be an external cavity laser, which is a tunable laser, whose oscillation wavelength is a wavelength controlled current such as a phase section current or a WBG section current. Determined by

In order to perform steps 540 and 550 after the step 530, the wavelength selector 119 receives the response optical signal including the response initialization information, which is response information about the link initialization information, from the light receiver 117. In step 113, it is indicated that the sequential designation is terminated. (S540, S550) Specifically, when receiving a response optical signal including response initialization information such as a message for performing autonegotiation or autodiscovery, the wavelength selection unit 119 Steps 540 and 550 are generated through an upper layer protocol unit for generating a link setting signal indicating that a link to be connected is established and instructing termination of sequential designation in the wavelength controller 113. Can be done.

That is, the upper layer protocol unit is a means for distinguishing and processing logical data from electrical signals of the transmitted response optical signals.

As mentioned above, the upper layer protocol unit may be implemented as one chip including the function of the initialization information generator 111. In particular, the chip may be implemented by a chip for implementing a link initialization function in Ethernet. Such chips include commercial Gigabit Ethernet chips, including 1000Base-X PCS, commercial EPON chips, including EPON MAC, and the like.

In general, higher layer protocol units that can be implemented by the chip or the like exchange information through a protocol promised to each other through a transmission line connected point-to-point or point-to-multipoint. This information exchange checks the state of interconnected transmission paths at the beginning of communication, and exchanges initial values necessary for the initialization of a link, which is optical wavelength alignment or other interconnected transmission paths. In general, the upper layer protocol unit expresses the link state detected through this initialization process to the external pin as an electrical signal.

The higher layer protocol unit may include a physical coding layer (Physical Coding Layer) and a physical media attachment (PMA) of 1000Base-X that performs autonegotiation.

Alternatively, the upper layer protocol unit may include a slave and a PMA of an Ethernet passive optical network media access control (EPON MAC) that performs an autodiscovery function.

The link module 140 of the OLT includes an optical receiver 141, a response information generator 143, and an optical transmitter 145.

In order to perform step 610, the optical receiver 141 of the link module 140 of the OLT transmits the designated optical signal to the designated optical signal of the output wavelength λ _k transmitted from the link module 110 of the ONT / ONU. Only when the link module 140 has a wavelength previously allocated to the link module 110 of the ONT / ONU, that is, only the assigned wavelength optical signal among the designated optical signals is received.

To perform steps 620 and 630 after step 610, the response information generator 143 of the link module 140 of the OLT determines whether the received allocated wavelength optical signal includes link initialization information (S620). When the link initialization information is included, response initialization information that is response information to the link initialization information is generated (S630).

The link initialization information may be the first auto-negotiation message that performs the auto-negotiation function as mentioned above, and in this case, the response initialization information may also be the second auto-negotiation message which is a response message to the first auto-negotiation message based on the auto-negotiation. Can be.

In addition, the link initialization information may be the first auto-discovery message that performs the auto-discovery function, as described above, and in this case, the response auto-discovery message may also be a response message to the first auto-discovery message based on the auto-discovery. Can be.

The response information generator 170 may be configured as a higher layer protocol unit that generates response initialization information based on the auto-negotiation function or the auto-discovery function for the link initialization information. That is, steps 620 and 630 may be performed through an upper layer protocol unit.

The upper layer protocol unit is composed of the same type as the upper layer protocol unit of the link module 110 of the ONT / ONU and includes the PCS and PMA of 1000Base-X that performs the auto-negotiation function, or the EPON that performs the auto-discovery function. It can be done including MAC master and PMA.

The link system having an optical wavelength alignment function according to the present invention may include the ONT / ONU link module 110 and the OLT link module 140.

3 is a diagram illustrating an embodiment of a link module of an ONT / ONU having an optical wavelength alignment function according to the present invention.

Referring to FIG. 3, the main components of the ONT / ONU link module 110, including a variable light source, for example an external resonant laser 330, are shown.

The link module 110 of the ONT / ONU is a higher layer protocol unit including the initialization information generator 111 and the wavelength selector 119. The parent board includes the EPON MAC slave or the 1000Base-X PCS / PMA 310. (mother board) and the optical transmitter 115 is equipped with an external resonant laser 330, the wavelength controller 113 is mounted a small control unit (Micro Control Unit: MCU) 320 and the wavelength determined by the light receiver 115 A child board equipped with an optical receiver 380 for receiving an optical signal to generate an electrical conversion signal may be configured to be connected to a connector. Signals connected to the connector pin are defined as general power, serial data transmission and reception signals, and serial signals for MCU communication. The MCU 320 performs control / monitoring of the external resonant laser 330 and communication with the outside, and WBG section control current Iw, which is a control current for controlling the external resonant laser 330, and And a control current generator for generating a phase section control current (Ip). It also includes a laser diode driver (LD driver) 370 to generate a data signal and a bias current (ECL bias current) of a suitable external resonant laser.

For the automatic wavelength alignment function implemented in the MCU 320, the LDON signal, the Link up signal, and the RESET signal should be connected from the upper layer protocol unit 310, and the signal level may be selected according to the input condition of the MCU. have. In addition, the MCU 320 may include a lookup table to generate a control current capable of outputting a designated optical signal having a specified output wavelength. Important signals used are:

a. RESET: Reset signal due to power ON / OFF or link failure

b. LDON: Always keep High for the upper layer protocol unit 310 including the PCS of 1000Base-X, and define the LDON signal of the EPON MAC for the upper layer protocol unit 310 including the EPON MAC. do.

c. Link up: In case of the upper layer protocol unit 310 including the PCS of 1000Base-X, it is a link setting signal (High Active) by the auto-negotiation function, and in the case of the upper layer protocol unit 310 including the EPON MAC, the automatic discovery is performed. Indicates the completion signal for setting the logical link identifier (LLID) by the function.

The link up signal is used as a signal for instructing the termination of the sequential designation to the MCU 320 as the wavelength controller 113.

4A is a diagram illustrating an embodiment of a link system using a PCS / PMA of 1000Base-X performing an auto-negotiation function as an upper layer protocol unit according to the present invention.

Referring to FIG. 4A, the link module 110 of the ONT / ONU of FIG. 4A may be in the form of a link module 110 of the ONT / ONU equipped with the legacy 1000Base-X PCS 310 of FIG. 3.

Currently, the PCS (420, 440) of 1000Base-X defined in IEEE 802.3z, which is most commonly used in the point-to-point communication environment between ONT / ONU (100) and OLT (130), has autonegotiation function as an initialization function of Ethernet link. It is included. Ethernet commercial chip including 1000Base-X PCS 440 of the link module 140 of the OLT and 1000Base-X PCS 420 of the link module 110 of the ONT / ONU is configured as an auto-negotiation message by an auto-negotiation procedure. The mutual information is exchanged using Ordered Set and Config Register. After confirming link setting with Acknowledge, the link status is transmitted to outside of chip through Link up signal.

Specifically, the auto-negotiation procedure of the PCS 420 of the link module of the ONT / ONU and the PCS 440 of the link module of the OLT is based on the normal configuration ordered-set and Config Register values received from the link module 110 of the ONT / ONU. When the PCS 440 of the link module of the OLT receives it, it determines an operation mode and generates a link up signal through mutual acknowledgment. When the output wavelength of the external resonant laser included in the optical transmitter 115 of the link module of the ONT / ONU matches the wavelength allocated by the link module 140 of the OLT, a normal optical signal is transmitted to generate a link up signal. If the output wavelength and the assigned wavelength do not match, the link up signal is not generated because a normal optical signal cannot be transmitted. Accordingly, when the link up signal is used in the structure of FIG. 4A capable of determining whether the wavelength matches, the automatic wavelength alignment function may be performed. In the present invention, such a point-to-point 1000Base-X operating environment is referred to as a continuous mode operating environment.

4B is a diagram illustrating an embodiment of a link system using an EPON MAC as an upper layer protocol unit performing an auto discovery function according to the present invention.

Referring to FIG. 4B, the link module 110 of the ONT / ONU of FIG. 4B may be in the form of a link module 110 of the ONT / ONU equipped with the legacy EPON MAC slave 310 of FIG. 3.

In case of Ethernet Passive Optical Network Media Access Control (EPON MAC) used in a point-to-multipoint environment between ONT 100 and OLT 130, the EPON MAC master of link module 140 of OLT. The EPON MAC slave 421 of the 441 and the link module 110 of the ONT / ONU has an auto discovery function for registering the ONT / ONU 100, that is, the link module 110 of the ONT / ONU. It is equipped. The automatic discovery procedure of the EPON MAC master 441 periodically transmits registration time window information from the link module 140 of the OLT to the EPON MAC slave 421 of the link module 110 of the ONU / ONT. . The link module 110 of the ONU / ONT sends a Register_Request message to the link module 140 of the OLT within the allocated time window, and the link module 140 of the OLT transmits the LLID to the ONU / ON through the register message. After the initial registration process by transmitting to the link module 110 of the ONT, the MAC chip 411 of the link module 110 of the ONU / ONT displays the status to the outside of the chip through the link up signal.

Therefore, the link up signal generated by the EPON MAC slave 421 mounted on the link module 110 of the ONT / ONU is set through a discovery handshake, which is a transmission / reception of a synchronization message. The external resonant lasers 115 and 330 generate the link up signal only when the OLT link module 140 operates at the assigned wavelength. Accordingly, the wavelength alignment function may be performed by using an EPON MAC-based higher layer protocol unit capable of determining wavelength matching. In the present invention, such a point-to-multipoint EPON MAC operating environment is referred to as a burst mode operating environment.

7 is a flow chart showing the flow of one embodiment of an optical wavelength alignment method in a link system according to the present invention. This will be described with reference to FIG. 2.

The optical wavelength alignment method illustrated in FIG. 7 may be performed in a link system including the link module 110 of the ONT / ONU and the link module 140 of the OLT shown in FIG. 2.

First, link initialization information is generated by the initialization information generating unit 111 in the link module 110 of the ONT / ONU (S710 and S510). The output wavelength is sequentially generated from a set of wavelengths that can be output from the wavelength control unit 113. If the output wavelength is specified, the optical transmitter 115 of the ONT / ONU link module 110 transmits the designated optical signal including the link initialization information to the designated output wavelength. S730, S530)

Next, the OLT link module 140 receives only an optical signal having an assigned wavelength among its designated optical signals through its optical receiver 141. (S740, S610) In this case, response information of the OLT link module 140 is generated. In step 143, the controller 20 determines whether the allocated wavelength optical signal includes link initialization information (S750, S620) and generates response initialization information when the link initialization information is included (S760, S630). The optical transmitter 145 of the OLT link module 140 receives the response initialization information and transmits a response optical signal including the response initialization information. (S770, S640).

When the wavelength selector 119 of the link module 110 of the ONT / ONU confirms that the optical receiver 117 receives the response optical signal (S780, S540), the wavelength designator 113 ends the sequential designation. (S790, S550)

8 is a timing diagram illustrating a flow of an embodiment of the continuous mode based optical wavelength alignment method through autonegotiation according to the present invention. The case where the link system of FIG. 1, FIG. 2 and the link module 110 of ONT / ONU in FIG. 3 are used is demonstrated.

First, the following two time parameters defined above are used to describe FIGS. 8 to 10. In other words, the optical stabilization time (OST) is a control current is applied after the output wavelength is designated by the MCU 320, through which the optical signal of the output wavelength is stably generated by the external resonant laser 330. Representation time (Registration Time (RT)) is the generation of a stable optical signal, and then transmits and receives a signal defined between upper layers (1000Base-X PCS / PMA or EPON MAC) through the stable optical signal, based on the higher layer The maximum expected time required for the Link up signal to occur in the protocol unit 310.

In addition, the following additional time parameter is defined.

Link Setup Time with Auto Negotiation / Discovery (ALST) means the time taken to establish a full duplex link by the 1000Base-X auto-negotiation function. RT must be set higher than ALST. In addition, * ALST is the link module 110 of the ONT / ONU delivers the link initialization information including the auto-discovery message to the link module 140 of the OLT and receives the LLID by the EPON-based auto-discovery function to establish the link. This is defined as the time taken to complete. The link setup time (LST) means a time required for link establishment after applying a reset signal from the upper layer protocol unit 310 of the ONT / ONU link module 110.

Referring to FIG. 8, in the continuous mode, the LDON signal of the upper layer protocol unit 310 is always in the ACTIVE state in the link module 110 of the ONT / ONU, and the algorithm is started by the reset signal 801. The 1000Base-X PCS included in the upper layer protocol unit 310 continuously transmits an Idle ordered set for code synchronization setting and a configuration order set for auto negotiation as link initialization information along with Power-ON. The information generated by the higher layer protocol unit is called upper layer information (ULI) for convenience. The ULI is modulated to a designated optical signal after the OST of the link module 110 of the ONT / ONU 803 and transmitted to the link. The designated designated optical signal on the link is transmitted to the link module 140 of the OLT only when it matches the wavelength allocated by the OLT link module 140, otherwise it is not transmitted to the link module 140 of the OLT. If not, the MCU 320 performing the optical wavelength automatic alignment procedure of the link module 110 of the ONT / ONU after the RT (Registration Time Out: RTO) 804 specifies the next output wavelength and the method. Repeat by When the idle ordered set and the configuration ordered set are transmitted to the OLT link module 140 due to the same wavelength, the OLT link module 140 transmits the response optical signal including the response initialization information by the auto-negotiation procedure to the ONT / ONT link module. The link is established in handshake mode to transmit the link up signal while transmitting to (110), and the wavelength automatic alignment procedure is completed.

9 is a timing diagram illustrating a flow of an embodiment of a burst mode based optical wavelength alignment method through automatic discovery according to the present invention. The case where the link system of FIG. 1, FIG. 2 and the link module 110 of ONT / ONU in FIG. 3 are used is demonstrated.

Referring to FIG. 9, in the burst mode, the LDON signal of the upper layer protocol unit 310 in the link module 110 of the ONT / ONU is a multiple layer that is a higher layer protocol to prevent collision with another link module of the ONT / ONU. It remains high only at the time allotted by the Multi-Point Control Protocol (MPCP). Therefore, as the link initialization information, ULI, which is a message for automatic discovery of EPON, can be delivered only within the LDON window designated by the link module 140 of the OLT. In addition, during the discovery process of the link module 110 of the initial ONU / ONT, the ULI for registration is generated at any time in the LDON window by an automatic discovery algorithm. This is specified in IEEE 802.3ah. The LDON signal in this burst mode is referred to as * LDON signal for convenience.

Therefore, in the burst mode, an RTO including at least one LDON window must be set after the OSTO 904 of the link module 110 of the ONT / ONU. The output wavelength of the designated optical signal including the ULI as the link initialization information of the link module 110 of the ONT / ONU transferred on the link in the LDON window only when it matches the wavelength allocated by the link module 140 of the OLT. It is delivered to the link module 140 of the OLT, otherwise it is not delivered to the link module 140 of the OLT. If it does not match, the MCU 320 which performs the automatic optical wavelength alignment procedure after the RTO 907 specifies the next output wavelength and repeats the above method. When the wavelength-matched register-request message, which is ULI as link initialization information, is transmitted to the link module 140 of the OLT, the register message, which is ULI as response initialization information, is responded by the link module 140 of the OLT by an automatic discovery procedure. It is included in the optical signal and transmitted to the link module 110 of the ONT / ONU, through which the LLID is assigned to the ONT / ONU 100, that is, the link module 110 of the ONT / ONU, and the Link up signal is generated. When the automatic light wavelength alignment procedure is completed.

FIG. 10 is a state transition diagram showing a state transition of an algorithm for aligning optical wavelengths in the wavelength controller 113 of the link module 110 of the ONT / ONU according to the present invention. This will be described with reference to the link module 110 of the ONT / ONU of FIG. 3.

Referring to FIG. 10, when the MCU 320 is the wavelength controller 113, the MCU 320 may generate an external resonant laser 330 capable of generating wavelengths λ _k ∈ {λ ₁ ,..., Λ _N }. And a lookup table 1030 indicating the control current value of the control unit. The operation is started by a RESET signal transmitted from the upper layer protocol unit 310. After setting the output wavelength value λ _k corresponding to k in the SET state 1000, the system transitions to the wait state 1010 in consideration of the * LDON signal, which is an event occurring after the OSTO, in the case of the OSTO and the burst mode. In the wait state 1010, the RT is initialized, and when the RTO is reached, the k is increased by 1 and then the state transitions to the SET state 1000.

If the link up signal indicates High before the RTO, the signal transitions to the run state 1020 to complete the algorithm. When k is larger than the defined N, the wavelength λ _k is λ ₁ to find an appropriate wavelength continuously.

When Reset is applied in the Run state 1020, λ ₁ is set to λ _k , the link state is monitored through a Link up signal input from a higher layer protocol unit, and an event is generated when an optical signal is not transmitted through the link. When a Link Down event occurs, the state transitions to the Set state 1000 while maintaining the current lambda _k value.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. 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 diagram showing a structure on a WDM-PON of a link system having an optical wavelength alignment function according to the present invention;

2 illustrates an embodiment of a link system having an optical wavelength alignment function according to the present invention;

3 is a view showing an embodiment of a link module of an ONT / ONU having an optical wavelength alignment function according to the present invention;

4A is a diagram illustrating an embodiment of a link system using a PCS / PMA of 1000Base-X as an upper layer protocol unit performing an autonegotiation function according to the present invention;

4B is a diagram illustrating an embodiment of a link system using an EPON-MAC as an upper layer protocol unit performing an auto discovery function according to the present invention;

5 is a flowchart showing an embodiment of the optical wavelength alignment method of the link module of the ONT / ONU according to the present invention;

6 is a flow chart showing the flow of one embodiment of an optical wavelength alignment method in a link module of an OLT according to the present invention;

7 is a flow chart showing the flow of one embodiment of an optical wavelength alignment method in a link system according to the present invention;

8 is a timing diagram showing the flow of an embodiment of the continuous mode based optical wavelength alignment method through autonegotiation according to the present invention;

9 is a timing diagram illustrating a flow of an embodiment of a burst mode based optical wavelength alignment method through automatic discovery according to the present invention;

FIG. 10 is a state transition diagram showing a state transition of an algorithm for aligning optical wavelengths in a wavelength controller of a link module of an ONT / ONU according to the present invention.

Claims (32)

An initialization information generation unit for generating link initialization information which is logical information of a predetermined format for checking a transmission status; A wavelength control unit that sequentially specifies an output wavelength that is a wavelength to be output from a set of outputable wavelengths; An optical transmitter for transmitting a designated optical signal which is an optical signal including the generated link initialization information at the designated output wavelength every time the output wavelength is designated by the wavelength controller; And And a wavelength selection unit for instructing termination of the sequential designation when the response optical signal including response initialization information, which is response information about the link initialization information, is received. Link module of (Optical Network Terminal / Optical Network Unit). The method of claim 1, The link initialization information is a first auto-negotiation message which is a message for performing an auto negotiation function. And the response initialization information is a second auto-negotiation message, which is a response message based on auto-negotiation with respect to the first auto-negotiation message. The method of claim 1, The link initialization information is a first auto discovery message which is a message for performing an auto discovery function. And the response initialization information is a second auto discovery message which is a response message based on the auto discovery for the first auto discovery message. The method of claim 1, wherein the wavelength control unit When the sequential designation termination instruction is generated in the wavelength selector within a predetermined time after designating the output wavelength, the sequential designation is terminated, and the sequential designation termination instruction is instructed by the wavelength selector within a predetermined time after designating the output wavelength. If is not generated, the link module of the optical subscriber network device, characterized in that for specifying the next output wavelength of the specified output wavelength. The method of claim 1, The wavelength control unit includes an output wavelength value designation unit that sequentially specifies the value of the output wavelength; And a control current generator for generating a control current corresponding to the value of the designated output wavelength when the output wavelength value designator is specified. The optical transmitter includes an external cavity laser for transmitting the designated optical signal corresponding to the control current when the control current generated by the control current generator is input. Link module of the device. The method of claim 5, The wavelength control unit may further include a look up table having a relationship between a control current value capable of generating an optical signal of each wavelength for each wavelength of the set of outputable wavelengths. And the control current generation unit generates a control current corresponding to the value of the specified output wavelength based on the lookup table. The method of claim 2 or 3, wherein the wavelength selection unit In case of receiving the response optical signal, a link setting signal, which is a signal indicating that a link to be connected is set, is generated and constitutes an upper layer protocol unit instructing the termination of the sequential designation in the wavelength controller. A link module of an optical subscriber network device. 8. The method of claim 7, wherein the higher layer protocol unit is A link module of an optical subscriber network device, comprising a physical coding layer of 1000Base-X and a physical media attachment, which perform an auto-negotiation function. 8. The method of claim 7, wherein the higher layer protocol unit is A link module of an optical subscriber network device comprising an Ethernet passive optical network media access control slave performing a self-discovery function and a physical medium connection. An optical receiver capable of receiving only an assigned wavelength optical signal, which is an optical signal of a pre-assigned wavelength; A response information generator for generating response initialization information, which is response information to the link initialization information, if the received wavelength-signal optical signal includes link initialization information that is logical information in a predetermined format for transmission state checking; And And an optical transmitter for transmitting a response optical signal, which is an optical signal including the generated response initialization information. 10. The link module of an optical line terminal. The method of claim 10, The link initialization information is a first auto-negotiation message, which is a message for performing an auto-negotiation function. And the response initialization information is a second auto-negotiation message which is a response message based on auto-negotiation of the first auto-negotiation message. The method of claim 10, The link initialization information is a first auto discovery message, which is a message for performing an auto discovery function. And the response initialization information is a second auto discovery message which is a response message based on the auto discovery for the first auto discovery message. The method of claim 11 or 12, wherein the response information generating unit And a higher layer protocol unit for generating the response initialization information based on an auto-negotiation function or an auto-discovery function with respect to the link initialization information. The method of claim 13, wherein the higher layer protocol unit A link module of an optical line termination device comprising a physical encoding sublayer of 1000Base-X performing an auto-negotiation function and a physical medium connection. The method of claim 13, wherein the higher layer protocol unit A link module of an optical line termination device comprising an Ethernet passive optical subscriber network medium access control master performing a self-discovery function and a physical medium connection. delete Generating link initialization information which is logical information in a predetermined format for checking the transmission status; Sequentially designating an output wavelength that is a wavelength to be output from a set of outputable wavelengths; Transmitting a designated optical signal which is an optical signal including the generated link initialization information at the designated output wavelength every time the output wavelength is designated; And And terminating the sequential designation when receiving a response optical signal including response initialization information that is response information about the link initialization information. (Optical Network Terminal / Optical Network Unit) Optical wavelength alignment of the link module. The method of claim 17, The link initialization information is a first auto-negotiation message, which is a message for performing an auto-negotiation function. And the response initialization information is a second auto-negotiation message which is a response message based on auto-negotiation with respect to the first auto-negotiation message. The method of claim 17, The link initialization information is a first auto discovery message, which is a message for performing an auto discovery function. And the response initialization information is a second auto discovery message which is a response message based on an auto discovery for the first auto discovery message. 18. The method of claim 17, wherein the step of sequentially specifying the output wavelength And the next output wavelength of the designated output wavelength is specified unless the sequential specification is completed within a predetermined time after the output wavelength designation. The method of claim 17, The step of sequentially specifying the output wavelength comprises the step of sequentially specifying the value of the output wavelength; And generating a control current corresponding to the value of the designated output wavelength upon the designation. The transmitting of the designated optical signal is performed by an external cavity laser which transmits the designated optical signal corresponding to the control current when the generated control current is input. How to align the optical wavelength of the link module. The method of claim 21, wherein generating the control current A value corresponding to the value of the specified output wavelength based on a look up table having a relationship between control current values capable of generating an optical signal of each wavelength for each wavelength in the set of outputable wavelengths; An optical wavelength alignment method of a link module of an optical subscriber network device, characterized by generating a control current. 20. The method of claim 18 or 19, wherein terminating the sequential designation When the response optical signal is received, the link generation signal, which is a signal indicating that the link to be established is generated, is performed through an upper layer protocol unit which indicates the termination of the sequential designation. Optical wavelength alignment method of link module of subscriber network device. The method of claim 23, wherein the higher layer protocol unit A method of aligning an optical wavelength of a link module of an optical subscriber network device, comprising a physical encoding sublayer of 1000Base-X performing an autonegotiation function and a physical medium connection. The method of claim 23, wherein the higher layer protocol unit An optical wavelength alignment method of a link module of an optical subscriber network device comprising an Ethernet passive optical subscriber network medium access control slave performing a self-discovery function and a physical medium connection. Receiving only an assigned wavelength optical signal, which is an optical signal of a pre-assigned wavelength; Generating the response initialization information that is response information to the link initialization information if the received wavelength-signal optical signal includes link initialization information that is logical information in a predetermined format for transmission status checking; And And transmitting a response optical signal, which is an optical signal including the generated response initialization information. 2. The optical wavelength alignment method of claim 1, wherein the response optical signal comprises a response optical signal. The method of claim 26, The link initialization information is a first auto-negotiation message, which is a message for performing an auto-negotiation function. And the response initialization information is a second auto-negotiation message which is a response message based on auto-negotiation with respect to the first auto-negotiation message. The method of claim 26, The link initialization information is a first auto discovery message, which is a message for performing an auto discovery function. And the response initialization information is a second automatic discovery message which is a response message based on the automatic discovery of the first automatic discovery message. The optical wavelength alignment method of the link module of the optical line terminating device in the WDM-PON. 29. The method of claim 27 or 28, wherein generating the response initialization information And an upper layer protocol unit for generating the response initialization information based on the auto-negotiation function or the auto-discovery function with respect to the link initialization information. 30. The system of claim 29, wherein the higher layer protocol unit is A method of aligning an optical wavelength in a link module of an optical line terminator, comprising a physical encoding sublayer of 1000Base-X performing an autonegotiation function and a physical medium connection. 30. The system of claim 29, wherein the higher layer protocol unit is An optical wavelength alignment method in a link module of an optical line termination device comprising an Ethernet passive optical subscriber network medium access control master performing an autodiscovery function and a physical medium connection. In the optical wavelength alignment method in a link system comprising a first link module of an optical network terminal (Optical Network Unit) and a second link module of an optical line terminal (Optical Line Terminal), Generating link initialization information which is logical information in a predetermined format for the transmission status check in the first link module; Sequentially specifying an output wavelength that is a wavelength to be output in the set of wavelengths output from the first link module; Transmitting, by the first link module, a designated optical signal that is an optical signal including the generated link initialization information at the designated output wavelength every time the output wavelength is designated; Receiving only an assigned wavelength optical signal, which is an optical signal of a pre-assigned wavelength, among the designated optical signals by the second link module; Generating, by the second link module, response initialization information that is response information to the link initialization information if the received allocated wavelength optical signal includes the link initialization information; Transmitting, by the second link module, a response optical signal that is an optical signal including the generated response initialization information; And And terminating the sequential designation when the response optical signal is received by the first link module.

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