KR102112785B1 - Wavelength selection system and method for multi-wavelength passive optical network - Google Patents

Abstract

The present invention relates to a wavelength selection system and a method for a multi-wavelength passive optical network (PON) and, specifically, to a wavelength selection system and the method for a multi-wavelength passive optical network, wherein for an ONT which performs transmission and reception through a specified wavelength and an OLT, the OLT quickly defines the transmission and reception wavelength of the ONT so that the ONT performs transmission and reception at the specified wavelength. According to one embodiment of the present invention, the wavelength selection system and the method for the multi-wavelength passive optical network, which minimize a delay required for the OLT to define and reflect an appropriate wavelength for a new ONT, and a delay required for reflecting the wavelength change if the OLT wants to change the wavelength of the ONT to adjust the communication load, the present invention has an effect of improving the stability and performance of the system.

Description

Wavelength selection system and method for multi-wavelength passive optical network

The present invention relates to a wavelength selection system and method for a multi-wavelength passive optical network (PON), in particular, for an ONT that performs transmission and reception at a specified wavelength with an OLT, the OLT quickly designates the transmission and reception wavelength of the ONT, It relates to a wavelength selection system and method for a multi-wavelength passive optical network that enables ONT to perform transmission and reception at a specified wavelength.

The passive optical network (PON) technology is for constructing a high-speed subscriber network, and is configured to process simultaneous access of multiple subscribers through a time division method or a wavelength division method. Among these methods, a time-sharing method with high cost-effectiveness is mainly used, such as EPON (Ethernet PON), 10G-EPON (10 Gigabit EPON), and ITUT (International Telecommunication Union) according to the Institute of Electrical and Electronics Engineers (IEEE) 802.3av / ah. Typical examples include-Gigabit PON (GPON) according to Telecommunication Standardization Sector (G.984 / 7), 10 Gigabit PON (XGPON), and NGPON2 (Next Generation PON) according to G.989.

Looking at the configuration of such a PON, one optical line terminal (OTL) installed in a telephone company and an optical network terminal (ONT) or optical network unit (ONU) of a plurality of subscribers are remote nodes, which are passive optical branch devices. It has a point-to-multipoint network structure through (using an optical splitter).

Figure 1 shows the configuration of a general PON, as shown, the OLT (1) with an optical transceiver (1a) for converting electrical signals and optical signals to each other through a remote node (RN) a plurality of subscriber ONT (2 ), Each of the ONT (2) is also composed of an optical transceiver (2a). Through this configuration, a high-speed communication service for a plurality of subscriber ONTs 2 can be provided.

2 is a conceptual diagram illustrating a downlink signal transmission method and an uplink signal transmission method of the PON. FIG. 2A is a conceptual diagram for explaining a downlink signal transmission method of a passive optical network. As illustrated, when the OLT 1 continuously transmits downlink data to be transmitted to the ONT 2, a plurality of ONTs 2_1 and 2_2 are It selects and receives frame data for itself from downlink frame data. Accordingly, such a downlink signal can continuously transmit data without signal collision only by continuously transmitting the signal modulated by the OLT 1 with its own clock. In addition, since all of the downlink signals made of the continuous data use the clock of the OLT (1), each ONT (2) only needs to restore and synchronize the clock for these downlink signals once.

However, in the case of an uplink signal in which ONT (2) transmits uplink frame data to OLT (1) as shown in FIG. 2B, when a plurality of ONTs (2_1, 2_2) randomly transmit an uplink signal, signals may collide. If the OLT (1), which knows the information (number, distance, etc.) about the ONT (2) transmits control information for the transmission time and data amount of the uplink signal for the individual ONT (2) through the downlink signal, each ONT ( 2_1 and 2_2) generate upstream burst signals of various sizes based on the corresponding control information and transmit them without collision.

As described above, the ONTs 2_1 and 2_2 generate upward signals of a predetermined data amount at different times and transmit them to the OLT 1, and each upward signal is divided into a guard section (a) to prevent collision. In the case of such an uplink signal, the signals are continuously segmented as shown, and since each signal uses its own clock of individual ONT (2_1, 2_2), the clocks of the uplink burst signal are not synchronized with each other or with the OLT clock. Therefore, there is a deviation from the clock of the OLT 1 that receives it.

That is, in the illustrated case, since the individual start points t1, t2, and t3 of the uplink burst signal have a deviation from the clock of the OLT (1), the OLT (1) restores the clock each time for each uplink burst signal and accordingly recovers data. The restoration process will be performed.

As the speed of communication increases, the communication speed is improved by changing the PON configuration using a single wavelength to a configuration using multiple wavelengths. By selecting multiple transmission wavelengths and multiple reception wavelengths between the OLT (1) and ONT (2), communication is performed. I am using the way to do it.

For example, λ1 is 1532nm for λ1, 1533nm for λ2, 1534nm for λ3, 1535nm for λ4, and λ5 is 1596nm for λ5, 1597nm for λ6, 1598nm for λ7, 1599nm for λ8, and 1599nm for λ8. Is selectively used.

In this case, the OLT should be able to transmit and receive multiple wavelength signals simultaneously using a plurality of laser diodes and a plurality of photodiodes, and in the case of ONT, transmit at a selected wavelength among a plurality of wavelengths, and also select a plurality of wavelengths Since it is necessary to receive in one wavelength, the transceiver's laser diode must use a tunable laser diode that can select the desired wavelength, and reception must also receive only the optical signal for a specified wavelength, so only a specified optical signal is selected by applying a tunable filter. To receive the photodiode.

Basically, in the case of such a tunable filter applied to ONT, there is a problem of increasing cost in that it is very expensive. Since only a signal of a set wavelength is received, it takes a long time to perform a wavelength setting process to change to another wavelength during use. This takes, and when a new ONT is connected to the OLT, it takes considerable time to determine the transmission / reception wavelength for the corresponding ONT and reflect it. Classes are classified according to the required time, and class 3 for general use requires a wavelength conversion time of less than 1 second. In the case of high class, it is possible to change the wavelength with a delay of several ms or hundreds-microseconds, but for this, a more expensive tunable filter is required, so there is a low economical limitation.

Therefore, in a PON configuration including ONT using a conventional tunable transceiver, when the OLT increases the communication load for a specific wavelength, it takes a long time to disperse some ONTs to other wavelengths, and there is a problem that communication becomes unstable. There is a problem in that the bandwidth of the reference wavelength is reduced because information regarding wavelength selection is exchanged with a fixed reference wavelength when a new ONT is connected.

As a result, research is being conducted to improve the performance of the system by allowing the wavelength to be set or updated quickly while reducing the cost of the tunable transceiver applied to the ONT in the multi-wavelength PON configuration.

Korean Patent Registration No. 10-1044412 [GEM frame synchronization circuit, system and method including the circuit] Korean Patent Publication No. 10-2014-0112903 [Upper wavelength allocation device and method in multi-wavelength optical communication system]

Therefore, the object of the present invention for solving this problem is to specify the appropriate wavelength for the new ONT in the multi-wavelength PON configuration and the delay necessary to reflect it and the OLT to change the wavelength of the ONT to adjust the communication load. It is to provide a wavelength selection system and method for a multi-wavelength passive optical network that can improve system stability and performance by minimizing the delay required to reflect a wavelength change for a wavelength.

Another object of the present invention is to maintain a communication performance while reducing the cost of a tunable transceiver applied to ONT in a multi-wavelength PON configuration, and to rapidly change the wavelength of use, and to reduce the power consumption. It is to provide a wavelength selection system and method for.

Another object of the present invention is that the OLT inserts information for wavelength selection into Psync data that has no problem in synchronization due to the characteristics of stable downlink frame data of PON even if there are some errors, and ONT wavelength selection information inserted into Psync data. It is possible to immediately change the wavelength by checking the physical layer, but by performing the Psync data verification in the SoC type Media Access Control (MAC) processing unit in the physical layer, it is possible to suppress the increase in cost. It is to provide a wavelength selection system and method for an optical network.

Another object of the present invention is to apply a low-cost fixed filter instead of using an expensive tunable filter at the receiver of the ONT transceiver for receiving a multi-wavelength optical signal, and use a set of photodiodes and transimpedance amplifiers as a plurality of optical receiving channels. The configured TO-CAN package type receiver is applied, and the limit amplifier and deserializer for receiving the corresponding channel are configured in the SoC type Media Access Control (MAC) processor, and receive signals according to the wavelength determination from the MAC processor. It is to provide a wavelength selection system and method for a multi-wavelength passive optical network that can reduce power consumption by shutting off power to a TO-CAN package type receiver that is not used by one power management unit.

In the wavelength selection system for a multi-wavelength passive optical network including OLT and ONT according to an embodiment of the present invention, the ONT is desired while tuning the wavelength of a pre-configured tunable laser diode that transmits an uplink signal to the OLT. It includes a laser diode driver for controlling the tunable laser diode to output the upward signal of the wavelength, according to the received light selected through a pre-configured fixed filter unit for dispersing the received light from the OLT to a predetermined light path A transceiver including a power management unit that provides power to only the used optical receiving unit and cuts off the power of the unused optical receiving unit among a plurality of pre-configured optical receiving units that generate a current signal and convert and amplify the voltage to a predetermined signal processing level, and All received from any one of the plurality of optical receivers Is compared with a reference voltage, outputs as a digital signal, selects PB data of PSBd from frame data generated by parallelizing the digital signal, and detects transmit / receive wavelengths based on information of a predetermined location in the Psync data. It may be characterized in that it comprises a MAC processor for providing information on the transmission wavelength to the laser diode driver, and providing power management information for the light receiving unit according to the information about the reception wavelength.

As an example related to the present invention, the transceiver includes a tunable laser diode that transmits an upward signal to the OLT, a laser diode driver that controls to output the desired upward signal while tuning the wavelength of the tunable laser diode, A fixed filter unit for dispersing the received light into a preset optical path, a photodiode generating a current signal according to the received light selected through the fixed filter unit, and a weak current generated by the photodiode are generated at a signal processing level. It includes; a plurality of optical receivers incorporating a transimpedance amplifier that converts and amplifies to voltage and a power management unit that provides power to only the optical receiver used among the plurality of optical receivers and cuts off the power of the unused optical receiver; The processing unit determines the voltage received from the plurality of light receiving units. PB data of PSBd is received from the frame data received from the plurality of parallel information generation units and the plurality of parallel information generation units, which consists of a limiting amplifier that outputs a digital value compared to a voltage and a deserializer that parallelizes the digital signals of the limiting amplifier. Selects, detects transmit / receive wavelengths based on information of a predetermined location in the corresponding Psync data, provides information on the corresponding transmit wavelengths to the laser diode driver, and provides power management information of the optical receiver according to the information on the received wavelengths It may be characterized in that it comprises a wavelength selector provided to the power management unit.

As an example related to the present invention, the power management unit may cut off the power of the remaining light receiving units except for a specific light receiving unit corresponding to the receiving wavelength among the plurality of light receiving units based on the information on the receiving wavelength. have.

As an example related to the present invention, each of the plurality of light receiving units may be characterized in that the photodiode and the transimpedance amplifier are integrally configured with a TO-CAN package type device.

As an example related to the present invention, when the ONT is a new ONT that is first registered in the OLT, the power management unit enables all light receiving units to be in an operating state and receives wavelength designation information for a new registered ONT at an arbitrary wavelength. The light is received from the OLT, and the MAC processing unit checks the wavelength designation information from frame data obtained from the received light containing the wavelength designation information, and transmits the wavelength designation information to the power management unit according to the wavelength designation information. After setting the wavelength, a new ONT registration process may be performed.

As an example related to the present invention, the OLT may be characterized by inserting information for wavelength selection related to the transmission / reception wavelength detected by the MAC processor in Psync data of downlink frame data included in the received light.

As an example related to the present invention, the MAC processing unit may check the transmission / reception wavelength information at a physical layer level based on information for selecting the wavelength included in Psync data.

As an example related to the present invention, if the MAC processing unit receives the Psync data at the same value at least twice, it is determined that it is the transmission / reception wavelength information, and the laser diode driver receives information on the transmission wavelength according to the transmission / reception wavelength information. It may be provided, and it is characterized in that the power management information of the light receiving unit according to the information on the reception wavelength included in the transmission / reception wavelength information is provided to the power management unit.

As an example related to the present invention, the OLT inserts fixed identification information different from the original Psync information when inserting information for wavelength selection at a part of the Psync data, and changes information in other areas to designate a transmission / reception wavelength. It may be characterized by designating a set of transmission / reception wavelengths using 2 bits.

In the wavelength selection method for a multi-wavelength passive optical network including OLT and ONT according to an embodiment of the present invention, the OLT performs optical communication to the ONT to determine whether a wavelength change is necessary for the ONT, and When a change is necessary, information for wavelength selection is inserted into Psync data of downlink frame data transmitted as an optical signal transmitted to the ONT, and a downlink data frame including a PSBd in which information for wavelength selection is inserted as an optical signal Transmitting to the ONT, and the transceiver constituting the ONT receives the received light corresponding to the optical signal received from the OLT through a plurality of channels and at least one of a plurality of pre-configured optical receivers corresponding to each one-to-one. And outputs an output voltage corresponding to the received light through the plurality of light receiving units for converting the received light into a voltage and outputting it. And the MAC processing unit constituting the ONT compares the output voltage with a reference voltage and outputs it as a digital signal, selects PB data of PSBd from the frame data generated by parallelizing the digital signal, and selects the corresponding Psync data. Checking whether or not to change the transmit / receive wavelength based on the information of the pre-promised location, and when the MAC processing unit confirms the information for selecting the wavelength for the transmit / receive wavelength change in the Psync data, select the wavelength. It may include the step of changing the transmission and reception wavelength of the transceiver based on the information for, and cutting off the power of the remaining light receiving unit except for the light receiving unit corresponding to the receiving wavelength of the plurality of light receiving units.

In the wavelength selection system and method for a multi-wavelength passive optical network according to an embodiment of the present invention, the OLT specifies an appropriate wavelength for a new ONT and the delay required to reflect it and the OLT changes the wavelength of the ONT to adjust the communication load. In this case, there is an effect of improving system stability and performance by minimizing the delay required to reflect the wavelength change.

In addition, in a multi-wavelength PON configuration, while maintaining the communication performance while reducing the cost of the tunable transceiver applied to the ONT, it is possible to respond quickly to changing wavelengths of use, and also to reduce the power consumption, which can satisfy both system performance, reliability, and economy. It has an effect.

Furthermore, OLT is intentionally adding error information to Psync data by inserting information for wavelength selection into Psync data, which has no problem in synchronization due to the nature of stable down-frame data of PON even if some errors exist, and ONT is added to Psync data. By checking the inserted wavelength selection information in the physical layer, it is possible to change wavelengths instantly by stably enabling high-speed wavelength setting or switching, reducing the burden of OLT registration of new ONTs or load balancing between ONTs. There is.

In addition, instead of using an expensive tunable filter at the receiver of ONT's transceiver for multi-wavelength optical signal reception, a TO-CAN package composed of a set of photodiodes and transimpedance amplifiers as a plurality of optical receiving channels is applied instead of a low-cost fixed filter. A type of receiver is applied, and the limit amplifier and deserializer for receiving the corresponding channel are composed of a SoC type media access control (MAC) processing unit and used by a power management unit that receives a signal according to a wavelength determination from the MAC processing unit. By configuring the multi-wavelength ONT transceiver economically by turning off the power of the TO-CAN package type receiver, which is not possible, the MAC processing unit can perform a part of the increased configuration to minimize the increase in the size of the ONT transceiver. There is an effect that can respond to (stick type, equipment type, etc.).

1 is an exemplary view showing a configuration of a conventional passive optical network.
2 is a conceptual diagram illustrating a downlink and uplink signal transmission method of a passive optical network.
3 is a conceptual diagram illustrating a downlink frame transmission method of a passive optical network.
Figure 4 is a first wavelength transceiver configuration of the ONT for multi-wavelength optical communication.
Fig. 5 is a configuration diagram of a second wavelength transceiver for multi-wavelength optical communication.
6 is a conceptual diagram for explaining a wavelength setting of an ONU (ONT) management and control interface (OMCI) level according to the addition of a new ONT in a multi-wavelength PON structure.
7 is a block diagram of an ONT transceiver and a MAC processing unit according to an embodiment of the present invention.
8 is a block diagram of a downlink physical frame according to an embodiment of the present invention.
9 and 10 are Psync data configuration diagram of a downlink physical synchronization block according to an embodiment of the present invention.
11 is a flowchart illustrating an operation method of a wavelength selection system for a multi-wavelength passive optical network according to an embodiment of the present invention.

It should be noted that the technical terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. In addition, technical terms used in the present invention should be interpreted as meanings generally understood by a person having ordinary knowledge in the technical field to which the present invention belongs, unless defined otherwise. It should not be interpreted as a meaning or an excessively reduced meaning. In addition, when the technical term used in the present invention is a wrong technical term that does not accurately represent the spirit of the present invention, it should be understood as being replaced by a technical term that can be correctly understood by those skilled in the art. In addition, the general terms used in the present invention should be interpreted as defined in the dictionary or according to context before and after, and should not be interpreted as an excessively reduced meaning.

In addition, the singular expression used in the present invention includes a plural expression unless the context clearly indicates otherwise. In the present invention, terms such as “consisting of” or “comprising” should not be construed to include all of the various components or steps described in the invention, and some of the components or some steps may not be included. It should be construed that it may or may further include additional components or steps.

Further, terms including ordinal numbers such as first and second used in the present invention may be used to describe elements, but the elements should not be limited by terms. The terms are used only to distinguish one component from other components. For example, the first component may be referred to as a second component without departing from the scope of the present invention, and similarly, the second component may be referred to as a first component.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings, but the same or similar elements will be given the same reference numbers regardless of the reference numerals, and redundant descriptions thereof will be omitted.

In addition, in the description of the present invention, when it is determined that detailed descriptions of related known technologies may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted. In addition, it should be noted that the accompanying drawings are only for easy understanding of the spirit of the present invention and should not be interpreted as limiting the spirit of the present invention by the accompanying drawings.

Particularly, in describing the present invention, the subscriber-side optical communication terminal is referred to as an ONT (Optical Network Terminal), but this is used to represent the subscriber-side optical communication terminal including the same concept of ONU (Optical Network Unit), so ONT is ONU. And other types of optical communication modems or optical communication terminal devices.

In addition, the embodiments of the present invention are described as an example of Gigabit PON (GPON) or XGPON (also referred to as 10Gigabit PON, XGSPON) according to ITUT (International Telecommunication Union-Telecommunication Standardization Sector) G.984 / 7, but G.989 The same for various types of passive optical network systems including NGPON2 (Next Generation PON) in accordance with, or Ethernet PON (EPON) in accordance with the Institute of Electrical and Electronics Engineers (IEEE) 802.3av / ah, or 10G-EPON (10Gigabit EPON) It can be applied in principle.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.

3 is a conceptual diagram for explaining a method for transmitting a downlink frame of a passive optical network, and the downlink frame data 10 for transmitting data in the physical layer is largely a Physical Synchronization Block (PSBd) corresponding to a header and a physical frame pay. It consists of a rod.

In the ITU-T standard specification, the downlink frame data 10 has a fixed length of 125 km, and in the case of the recently discussed XGS-PON, one downlink frame data has a size of 155520 bytes at a rate of 9.95328 Gbit / s.

The PSBd includes synchronization data for synchronization, sequence numbers of frames, and operation control information. If communication is actually being performed, synchronization of each ONT (2) is easily performed for continuous frame downlink reception. In this case, even if there are some errors in the synchronization signal included in the PSBd, synchronization is achieved without problems.

FIG. 4 is a configuration diagram of a first type transceiver for ONT for multi-wavelength optical communication. As shown, a tunable transceiver 20 for multi-wavelength optical communication and a MAC processing unit 30 interworked therewith are shown.

The laser diode for transmitting the upward signal is a tunable laser diode 25 as shown, and a laser diode driver 26 configured to output a desired signal while tuning the wavelength of the tunable laser diode 25 is configured. In general, the tunable laser diode 25 may provide a laser output of a desired wavelength by setting an operating temperature including a precise temperature control configuration.

On the other hand, looking at the configuration of the receiving unit for receiving a downlink signal, a tunable filter 21 for selecting a selected one of a plurality of wavelengths (λ5 to λ8), and the reception selected through the tunable filter 21 A photodiode 22 for generating a current signal according to light, a transimpedance amplifier (TIA) 23 for amplifying and converting the weak current generated by the photodiode 22 into a voltage at a signal processing level, and a transimpedance amplifier And a limiting amplifier 24 for comparing the output voltage of (23) with a reference voltage and outputting it as a digital value. The uplink signal is controlled by the ONT MAC processing unit 30, and the downlink signal is transmitted to the ONT MAC processing unit 30 to perform subsequent data processing.

In this configuration, the tunable filter 21 is very expensive and has a problem in that it is not easy to mass-produce the transceiver due to variable filter characteristics. In addition, when the speed of wavelength selection is slow and a specific wavelength is selected, there is a limitation that a signal received at another wavelength cannot be checked at all.

Therefore, it is possible to configure the receiver of the method shown in FIG. 5 while taking the problem of increasing the size of the transceiver and also taking the complexity of assembly.

FIG. 5 is a configuration diagram of a second-way transceiver for multi-wavelength optical communication. This is an unusual method. When using such a configuration, since the size of the transceiver increases, there is a problem that it is not easy to configure the ONT in the form of a plug type stick. have.

The transceiver 40 as shown is composed of a tunable laser diode 45 and a laser diode driver 46.

In addition, looking at the configuration of the receiver in the transceiver 46 for receiving the downlink signal, a fixed filter (for example, four for four wavelengths) that distributes each of the plurality of wavelengths (λ5 to λ8) to a corresponding output path. Configuration having different output paths) 41 and photodiode PD generating a current signal according to the received light selected through the fixed filter 41 and weak current generated by the photodiode PD A plurality of optical receivers 42 configured with an integrated transimpedance amplifier (TIA) for converting and amplifying to a voltage of a signal processing level are configured.

In this case, the photodiode and the transimpedance amplifier are arranged in a single package by arranging semiconductor elements adjacent to each other to amplify the micro-current, and typically use a TO-CAN package type receiver element.

In addition, an analog switch 43 for transmitting the output voltage received from the plurality of optical receivers 42 to the limiting amplifier 44 is configured in the transceiver 40, the output transmitted through the analog switch 43 The voltage is transmitted to the ONT MAC processing unit 30 through the limiting amplifier 44.

At this time, the ONT MAC processing unit 30 internally serializes the parallel data for generating an uplink signal (SER) 31 and the deserializer (DES) 32 for parallelizing the received downlink data. Included, internally, it processes data transmitted and received based on parallel data.

6 is a conceptual diagram for explaining a wavelength setting of an ONU (ONT) management and control interface (OMCI) level according to the addition of a new ONT in a multi-wavelength PON structure, when a new ONT (ONT n + 1) is added, OLT (1) ) Must provide the wavelength information to be used for the new ONT. In the case of the new ONT, the basic wavelengths (eg, λ1, λ5) are specified, and through this, the process of registration, distance measurement, and use wavelength designation through new access through OMCI Is performed.

Upon completion of this process, the new ONT will communicate after adjusting the tunable laser diode and the tunable filter of the transceiver to the designated wavelength. Since this process is performed by checking the information inside the frame at the upper layer, not the physical layer, it takes a considerable amount of time, and depending on the class, delays ranging from several ms to several seconds occur.

Therefore, the delay required for new ONT registration is long, and the process of changing the wavelength for communication load management (load balancing) during OLT is not easily performed.

The present invention is intended to solve this problem, and when the OLT designates an appropriate wavelength for a new ONT and the delay necessary to reflect it, and when the OLT wants to change the wavelength of the ONT to adjust the communication load, it reflects the wavelength change therefor. In addition to minimizing the necessary delay, the cost of the tunable transceiver applied to the ONT is maintained while maintaining communication performance, the wavelength change can be quickly responded, and the power consumption can be reduced.

This will be described with reference to FIGS. 7 to 10.

7 is a diagram illustrating an ONT configuration including a transceiver and a MAC processing unit in a wavelength selection system for a multi-wavelength passive optical network including an OLT and one or more ONTs according to an embodiment of the present invention.

As illustrated, the ONT controls the tunable laser diode 113 to output the uplink signal of a desired wavelength while tuning the wavelength of the preconfigured tunable laser diode 113 that transmits the uplink signal to the OLT. It includes a laser diode driver 114, and generates a current signal according to the received light selected through a pre-configured fixed filter unit 111 that disperses the received light received from the OLT into a preset optical path, and then sets a preset signal. A power management unit 115 that provides power to only the light receiving unit 112 used among a plurality of preconfigured light receiving units 112 that converts and amplifies the voltage to a processing level and cuts off the power of the light receiving unit 112 that is not used includes The voltage received from any one of the transceiver 110 and the plurality of light receiving units 112 is compared with a reference voltage and output as a digital signal. The PSBd Psync data is selected from the frame data generated by parallelizing the digital signal, the transmission / reception wavelength is detected based on the information of the predetermined location in the Psync data, and the information on the transmission wavelength is transmitted to the laser diode driver 114 ), And may include a MAC processor 120 that provides power management information of the light receiving unit according to the information on the received wavelength to the power management unit 115.

When the configuration of the transceiver 110 and the MAC processor 120 is described in more detail, the transceiver 110 includes a tunable laser diode 113 that transmits an uplink signal to the OLT, and a wavelength of the tunable laser diode. The laser diode driver 114 for controlling to output the desired upward signal while tuning, a fixed filter unit 111 for dispersing the received light into a preset optical path, and selected through the fixed filter unit 111 A plurality of optical receivers 112 including a photodiode (PD) generating a current signal according to the received light and a transimpedance amplifier (TIA) that converts and amplifies the weak current generated by the photodiode into a voltage having a signal processing level. ) And the power management unit 115 that provides power to only the light receiving unit 112 used among the plurality of light receiving units 112 and cuts off the power of the light receiving unit 112 which is not used. ).

Here, the light receiving unit may be in the form of a TO-CAN package type device in which a photodiode (PD) and a transimpedance amplifier (TIA) are integrated.

In addition, the MAC processing unit 120 parallelizes the digital signals of the limiting amplifier LA and the limiting amplifier LA outputting the voltage received from the plurality of optical receivers 112 as a digital value and outputting it as a digital value. PSBd Psync data is selected from the frame data received from the plurality of parallel information generating units 122 and the plurality of parallel information generating units 122 composed of a deserializer (DES), and a predetermined location in the corresponding Psync data It detects the transmission and reception wavelengths based on the information of, provides information on the transmission wavelength to the laser diode driver 114, and provides power management information to the light receiving unit according to the information on the reception wavelength to the power management unit 115 A wavelength selector 123 may be included.

In this case, the plurality of light receiving units 112 may be connected to each other in a one-to-one correspondence according to the wavelengths corresponding to the plurality of parallel information generating units 122.

In addition, the MAC processor 120 includes a serializer (SER) 121 that serializes internally parallel data for generating an uplink signal, and the wavelength selector 123 through the serializer 121 Information about the transmission wavelength may be transmitted to the laser diode driver 114.

In addition, the power management unit 115, on the basis of the information on the received wavelength provided by the wavelength selection unit 123, the remaining light receiving unit except for a specific light receiving unit corresponding to the receiving wavelength of the plurality of light receiving unit 112 Can cut off the power.

In addition, when the ONT is a new ONT that is first registered in the OLT, the power management unit 115 sets all the light receiving units 112 configured in the transceiver 110 into an operating state, and for the new registered ONT at an arbitrary wavelength. The received light including wavelength designation information may be received from the OLT.

In addition, the MAC processing unit 120 checks the wavelength designation information from frame data obtained from the received light including the wavelength designation information and transmits the wavelength designation information to the power management unit 115 according to the wavelength designation information. After setting the wavelength, a new ONT registration process can be performed.

That is, the power management unit 115 does not receive the wavelength designation information for the new registration ONT at a fixed reference wavelength by making all the light receiving units 112 in an operating state in the case of the new ONT registration, and the new registration ONT at any wavelength. It is also possible to receive wavelength designation information.

This makes it possible to prevent the situation in which the band for the reference wavelength is reduced by providing the wavelength designation information for the newly registered ONT only with the fixed reference wavelength. That is, the wavelength designation information of the newly registered ONT can be inserted into a downlink frame of the wavelength with the lowest current load and broadcast, and the ONT according to an embodiment of the present invention checks the wavelength designation information inserted into the downlink frame of an arbitrary wavelength. Accordingly, after setting the wavelength, a new ONT registration process may be performed.

FIG. 8 shows the configuration of the downlink frame data, and as shown, one downlink frame data consists of a PSBd (Physical Synchronization Block, downstream) 310 and a physical frame payload 320 corresponding to the header. The PSBd 310 includes 8 bytes of synchronous data (Psync) 311, 8 bytes of sequence number information (SFC: SuperFrame Counter structure) 312, and 8 bytes of operation control information (OC) 313. It consists of.

The sequence number information 312 and the operation control information 313 are composed of 51 bits of practical information and 13 bits of header error correction information, respectively. That is, among the information constituting the PSBd 310, the sequence number information 312 and the operation control information 313 corresponding to the actual header information are HEC (Header Error Correction) information that can be corrected even if an error occurs in the corresponding data. Since is included, even if an error occurs in some bits, normal data can be restored.

Of course, the physical frame payload which is real data also includes forward error correction (FEC) information for error correction.

Therefore, since data having substantial information in downlink frame data can be corrected even if an error occurs in some bits, it is possible to transmit data robust to bit errors generated in the line.

Of all the downlink frame data, only synchronization data for synchronization, that is, 8-byte Psync, does not contain information on error detection or correction, which is a unique synchronization code (fixed 64-bit pattern) corresponding to 8 bytes. This is to accurately determine the starting position of the frame data. As an example, XGS-PON has a value of '0xC5E51840 FD59BB49'. The probability that a specific value of 64 bits exists in a region other than Psync has a probability of 1/2 ⁶⁴ and thus rarely occurs. Therefore, in the current standard, when 64 bits that exactly match these special fixed values are received, the start position of the downlink frame can be specified, and the received information is corrected even if a slight error occurs, thereby improving reception performance. Is regulated.

However, as described above, in the case of downlink frame data, since the data is repeated at a uniform rate, synchronization through Psync is less likely to fail, and even if some errors are included in a few bits, there is no problem in synchronization.

Therefore, in the embodiment of the present invention, even if there are some errors in the OLT, information for wavelength selection (error information) is inserted into the Psync data that has no problem in synchronization due to the characteristics of the stable down frame data of the PON.

That is, the OLT may insert information for selecting wavelengths related to the transmission / reception wavelengths detected by the MAC processing unit 120 of the ONT in Psync data of downlink frame data included in the received light.

In addition, the wavelength selection unit 123 of the MAC processing unit 120, which receives this and grasps the start position of the received frame, confirms information for selecting the wavelength included in the Psync for synchronizing the start position of the corresponding frame. Information is immediately available at the physical layer level. Of course, when receiving the synchronization information at the same value at least twice, it may be confirmed that the wavelength setting information.

For example, the wavelength selection unit 123 of the MAC processing unit 120 is the transmission / reception wavelength information (or information for wavelength selection) when the Psync data is received at the same value at least twice (or two or more times). It is determined, and provides information on the transmission wavelength according to the transmission / reception wavelength information to the laser diode driver 114, and the power management unit provides power management information on the light receiving unit according to the information on the reception wavelength included in the transmission / reception wavelength information. 115).

9 is a diagram illustrating Psync data configuration of a downlink physical synchronization block according to an embodiment of the present invention, and inserting information for wavelength selection at a portion of the Psync 311, after designating a 4 bit region, 2 bits at a corresponding location Is for transmitting wavelength, and 2 bits is for receiving wavelength.

In this case, when the same information is received for a certain number of times to distinguish it from normal Psync information and Psync information including actual errors, it is considered that wavelength selection information is included and the wavelength can be changed.

10 is a block diagram of Psync data of a downlink physical synchronization block according to another embodiment of the present invention, in which information for wavelength selection is inserted at a part of the Psync 311, fixed identification information different from the original Psync information is inserted, and (For example, the original 01 information is changed to 10.) It is a case where it is promised to designate a transmission / reception wavelength by changing information in another area.

Of course, as shown in the figure, 6 bits or 8 bits can be used for the selection of the identification information and the wavelength, but since the set of the transmission wavelength and the reception wavelength is usually fixed, the transmission / reception wavelength using 2 bits as illustrated You can also specify a set.

11 is a flowchart illustrating an operation method of a wavelength selection system for a multi-wavelength passive optical network according to an embodiment of the present invention.

As shown in the figure, the OLT performs optical communication to the ONT to determine whether a wavelength change for the ONT is necessary.

When a wavelength change is required as a result of the determination, the OLT may insert information for wavelength selection into Psync data of downlink frame data transmitted as an optical signal transmitted to the ONT.

In addition, the OLT transmits a downlink data frame including a PSBd in which information for the wavelength selection is inserted as an optical signal to the ONT.

On the other hand, the transceiver constituting the ONT receives the received light corresponding to the optical signal received from the OLT through at least one of a plurality of channels and a plurality of pre-configured optical receivers corresponding to each one-to-one, and receives the received light. The output voltage corresponding to the received light is output through any one of the plurality of light receiving units which is converted to a voltage and output.

In addition, the MAC processing unit constituting the ONT compares the output voltage with a reference voltage and outputs it as a digital signal, selects PB data of PSBd from frame data generated by parallelizing the digital signal, and promises in advance from the Psync data It is possible to check whether the transmission / reception wavelength is changed based on the location information.

In addition, when the transmission / reception wavelength information for changing the transmission / reception wavelength is confirmed in the Psync data as a result of the verification, the MAC processing unit changes the transmission / reception wavelength of the transceiver based on the transmission / reception wavelength information, and the received wavelength among the plurality of optical receivers. The power of the remaining light receiving units other than the corresponding light receiving unit may be cut off.

Through this method, instead of using an expensive tunable filter at the receiver of ONT's transceiver for multi-wavelength optical signal reception, a low-cost fixed filter is applied, and the TO- consisting of a set of photodiodes and transimpedance amplifiers as a plurality of optical receiving channels A CAN package type receiver is applied, and the limit amplifier and deserializer for receiving the corresponding channel are composed of a SoC type MAC (Media Access Control) processor and a power management unit that receives a signal according to the wavelength determination from the MAC processor. The multi-wavelength ONT transceiver can be economically configured by cutting off the power of the TO-CAN package type receiver that is not used, while the MAC processing unit can perform a part of the increased configuration to minimize the increase in the size of the ONT transceiver. It will be able to respond to ONT configuration (stick type, equipment type, etc.).

The above-described contents may be modified and modified without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present invention.

1: OLT 1a: Optical transceiver
2: ONT 2a: Optical transceiver
10: Downlink frame data 110: Transceiver
111: fixed filter 112: light receiving unit
113: tunable laser diode 114: laser diode driver
115: power management unit 120: MAC processing unit
121: serializer 122: parallel information generation unit
123: wavelength selector

Claims (10)

In the wavelength selection system for a multi-wavelength passive optical network including OLT and ONT,
The ONT
And a laser diode driver that controls the tunable laser diode to output the upward signal having a desired wavelength while tuning a wavelength of a preconfigured tunable laser diode that transmits an upward signal to the OLT, and receives light received from the OLT. Power is supplied only to the optical receiver used among the plurality of preconfigured optical receivers that generate a current signal according to the received light selected through a pre-configured fixed filter unit that disperses the signal into a preset optical path and converts and amplifies it into a voltage of a preset signal processing level A transceiver including a power management unit that provides and cuts off the power to the unused optical receiver; And
The voltage received from any one of the plurality of optical receivers is compared with a reference voltage and output as a digital signal, and the PB data of PSBd is selected from frame data generated by parallelizing the digital signal, and the Psync data is previously promised. MAC processing unit that detects transmit / receive wavelengths based on location information, provides information on the transmission wavelength to the laser diode driver, and provides power management information to the light receiving unit according to the information on the receiving wavelength.
Wavelength selection system for a multi-wavelength passive optical network comprising a.
The method according to claim 1,
The transceiver,
A tunable laser diode that transmits an upward signal to the OLT;
A laser diode driver that controls to output the desired upward signal while tuning the wavelength of the tunable laser diode;
A fixed filter unit for dispersing the received light into a preset optical path;
A plurality of light receiving units including a photodiode generating a current signal according to the received light selected through the fixed filter unit and a transimpedance amplifier converting and amplifying the weak current generated by the photodiode into a voltage at a signal processing level; And
It includes; a power management unit that provides power only to the optical receiver used among the plurality of optical receivers and cuts off the power of the unused optical receiver;
The MAC processing unit,
A plurality of parallel information generators comprising a limiting amplifier outputting the voltage received from the plurality of optical receivers as a reference voltage as a digital value and a deserializer parallelizing the digital signals of the limiting amplifier; And
The PSBd Psync data is selected from the frame data received from the plurality of parallel information generation units, and the transmission / reception wavelength is detected based on information of a predetermined location in the corresponding Psync data, and the information on the transmission wavelength is the laser diode. A wavelength selection unit provided to a driver and providing power management information of a light receiving unit according to information on a received wavelength to a power management unit
Wavelength selection system for a multi-wavelength passive optical network comprising a.
The method according to claim 1,
The power management unit selects a wavelength for a multi-wavelength passive optical network, characterized in that it cuts off the power of the remaining optical receivers except for a specific optical receiver corresponding to the received wavelength among the plurality of optical receivers based on the information on the received wavelength. system.
The method according to claim 2,
Each of the plurality of optical receivers is a wavelength selection system for a multi-wavelength passive optical network, characterized in that each of the photodiode and the transimpedance amplifier is a package type device that is integrally formed.
The method according to claim 1,
When the ONT is a new ONT that is first registered with the OLT, the power management unit causes all light receiving units to operate, and receives received light including wavelength designation information for the new registered ONT at an arbitrary wavelength from the OLT,
The MAC processor checks the wavelength designation information from frame data obtained from the received light including the wavelength designation information, transmits the wavelength designation information to the power management unit, sets a wavelength according to the wavelength designation information, and then registers a new ONT Wavelength selection system for a multi-wavelength passive optical network, characterized in that to perform the process.
The method according to claim 1,
The OLT is a wavelength selection system for a multi-wavelength passive optical network, characterized in that information for selecting wavelengths related to the transmission / reception wavelengths detected by the MAC processing unit is inserted into Psync data of downlink frame data included in the received light.
The method according to claim 6,
The MAC processing unit is based on the information for selecting the wavelength included in the Psync data, the wavelength selection system for a multi-wavelength passive optical network, characterized in that for checking the transmission and reception wavelength information at the physical layer level.
The method according to claim 7,
When receiving the Psync data at the same value at least twice, the MAC processing unit determines that it is the transmission / reception wavelength information, and provides information on the transmission wavelength according to the transmission / reception wavelength information to the laser diode driver, and the transmission / reception wavelength information Wavelength selection system for a multi-wavelength passive optical network, characterized in that to provide power management information for the optical receiver according to the information on the received wavelength included in the power management unit.
The method according to claim 6,
The OLT inserts fixed identification information different from that of the original Psync when inserting information for wavelength selection at a part of the Psync data, changes the information in other areas to designate the transmit / receive wavelength, and transmits and receives using 2 bits. A wavelength selection system for a multi-wavelength passive optical network characterized by specifying a set of wavelengths.
In the wavelength selection method for a multi-wavelength passive optical network including OLT and ONT,
The OLT performs optical communication to the ONT to determine whether a wavelength change is necessary for the ONT, and when a wavelength change is necessary, for selecting a wavelength in Psync data of downlink data transmitted as an optical signal transmitted to the ONT Inserting information and transmitting a downlink data frame including a PSBd in which the information for wavelength selection is inserted, to the ONT as an optical signal;
The transceiver constituting the ONT receives the received light corresponding to the optical signal received from the OLT through at least one of a plurality of channels and a plurality of pre-configured optical receivers corresponding to each one-to-one, and receives the received light as a voltage. Outputting an output voltage corresponding to the received light through the plurality of light receiving units converting and outputting;
The MAC processing unit constituting the ONT compares the output voltage with a reference voltage, outputs it as a digital signal, selects PB data of the PSBd from frame data generated by parallelizing the digital signal, and pre-appointed locations in the Psync data Checking whether a transmission / reception wavelength is changed based on the information of; And
When the MAC processing unit confirms the information for selecting the wavelength for changing the transmission / reception wavelength in the Psync data as a result of the verification, changes the transmission / reception wavelength of the transceiver based on the information for selecting the wavelength, and among the plurality of optical receivers Cutting off the power of the other light receiving units except the light receiving unit corresponding to the reception wavelength;
Wavelength selection method for a multi-wavelength passive optical network comprising a.

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