KR102469727B1 - Method for registering a new optical network unit in a passive optical network and an optical line terminal performing the same - Google Patents

Abstract

A method for registering a new optical network unit in a passive optical network and an optical line terminal performing the same are disclosed. A method of registering a new optical network unit (ONU) performed by an optical line terminal (OLT) includes periodically receiving a registration request of a new ONU existing in a service area; if the registration request for the new ONU is received in a first cycle period, stopping allocation of bandwidth to ONUs currently in service in a second cycle period immediately after the first cycle period; broadcasting a serial number request message for registration of a new ONU existing in the service area in a third cycle period immediately after the cycle period in which the uplink data transmission is completed, when uplink data transmission of the currently serving ONUs is completed; ; and when a serial number response message is received from the new ONU in response to the serial number request message, registering the new ONU that has transmitted the serial number response message, wherein the broadcasting step extends the service area within a radius. According to , the serial number request message can be broadcast by dividing the virtual area into a plurality of virtual areas and adjusting the size of a quiet window based on the number of the divided virtual areas.

Description

Method for registering a new optical network unit in a passive optical network and an optical line terminal performing the same}

The present invention is a new optical network unit (Optical Network Unit, ONU) relates to a method of providing registration.

In Time Division Multiple Access (TDMA) passive optical network technology (TDMA-PON), one Optical Line Terminal (OLT) and multiple ONUs connect point-to-multipoint through a passive optical splitter. (Point-to-Multipoint) connection method. Accordingly, the TDMA-PON technology transmits signals in a downlink broadcast method and transmits signals in an uplink method in a burst method.

In the conventional TDMA-PON technology, a quiet window with a period of 250 μs is used for registration of a new ONU. This is a time for discovering ONUs existing at a distance of a minimum of 0 km and a maximum of 20 km. Therefore, during this time, the upstream bandwidth is not allocated 2 cycles in advance to prevent normally registered ONUs from transmitting data. That is, for the quiet window period, the OLT controls ONUs that are already in service not to transmit data so that registration is possible without colliding with signals of ONUs that have not yet been discovered.

Recently, however, network operators are seeking to accommodate 5G mobile fronthaul and backhaul services through next-generation TDMA-PON technology. In particular, to accommodate the mobile fronthaul service, a delay time of 150 μs or less must be guaranteed in the PON section. However, in the conventional TDMA-PON technology, a quiet window period of 250 μs is used for discovering and registering a new ONU, and as a result, a delay time of 250 μs occurs for ONUs already registered and in service.

Accordingly, a method for controlling a quiet window capable of ensuring low latency is required in order to accommodate a mobile fronthaul service in the conventional TDMA-PON technology.

The present invention divides a service area into a plurality of virtual zones according to the distance or installation information of ONUs measured in advance, and adjusts the size of a quiet window based on the number of divided virtual zones to discover and discover new ONUs. A method and apparatus capable of guaranteeing a short delay while registering are provided.

A method for registering a new optical network unit (ONU) performed by an optical line terminal (OLT) according to an embodiment of the present invention includes periodically receiving a registration request for a new ONU existing in a service area. step; if the registration request for the new ONU is received in a first cycle period, stopping allocation of bandwidth to ONUs currently in service in a second cycle period immediately after the first cycle period; broadcasting a serial number request message for registration of a new ONU existing in the service area in a third cycle period immediately after the cycle period in which the uplink data transmission is completed, when uplink data transmission of the currently serving ONUs is completed; ; and when a serial number response message is received from the new ONU in response to the serial number request message, registering the new ONU that has transmitted the serial number response message, wherein the broadcasting step extends the service area within a radius. According to , the serial number request message can be broadcast by dividing the virtual area into a plurality of virtual areas and adjusting the size of a quiet window based on the number of the divided virtual areas.

The serial number request message includes an identifier for distinguishing a service area divided into a plurality of virtual areas according to the radius, and a new ONU existing in the service area includes a serial number request message including an identifier corresponding to its own location. In response, a serial number response message may be transmitted to the OLT.

Upon receiving the serial number request message from the OLT, the new ONU may transmit the serial number response message to the OLT after a minimum response time and a random delay time.

The step of registering the new ONU may include allocating an identifiable ID to the new ONU that has transmitted the serial number response message; and completing the registration of the new ONU by measuring a distance to the new ONU to which the ID is assigned and allocating a correction value.

An Optical Line Terminal (OLT) according to an embodiment of the present invention includes a processor, and the processor periodically receives a registration request of a new ONU existing in a service area, and transmits the registration request of the new ONU. If reception is received in the first cycle period, bandwidth allocation to the currently serving ONUs is stopped in the second cycle period immediately after the first cycle period, and when the uplink data transmission of the currently serving ONUs is completed, the uplink A serial number request message for registration of a new ONU existing in the service area is broadcasted in the third cycle immediately after the cycle period in which data transmission is completed, and a serial number response message is received from the new ONU in response to the serial number request message. is received, the new ONU that has transmitted the serial number response message is registered, the service area is divided into a plurality of virtual areas according to the radius, and a quiet window is created based on the number of the divided virtual areas. The serial number request message can be broadcast by adjusting the size of .

The serial number request message includes an identifier for distinguishing a service area divided into a plurality of virtual areas according to the radius, and a new ONU existing in the service area includes a serial number request message including an identifier corresponding to its own location. In response, a serial number response message may be transmitted to the OLT.

Upon receiving the serial number request message from the OLT, the new ONU may transmit the serial number response message to the OLT after a minimum response time and a random delay time.

The processor completes the registration of the new ONU by allocating an identifiable ID to the new ONU that has transmitted the serial number response message, measuring the distance to the new ONU to which the ID is assigned, and allocating a correction value. can do.

According to the present invention, a service area is divided into a plurality of virtual areas according to the distance or installation information of ONUs measured in advance, and the size of a quiet window is adjusted based on the number of divided virtual areas. Latency can be guaranteed.

1 is a diagram illustrating a first method of discovering and registering a new ONU in TDMA-PON according to an embodiment of the present invention.
2 is a diagram illustrating a method of discovering a new ONU by dividing a service area into a plurality of virtual zones according to an embodiment of the present invention.
3 and 4 are diagrams illustrating a procedure of discovering and registering a new ONU using multiple quiet windows.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a first method of discovering and registering a new ONU in TDMA-PON according to an embodiment of the present invention.

1 shows an example in which a quiet window with a period of 250 μs is applied in order for the OLT to discover new ONUs existing in a service area of a minimum distance of 0 km to a maximum of 20 km. A procedure for the OLT to discover and register new ONUs in TDMA-PON is as follows.

① First, the OLT may receive a registration request for a new ONU existing in the service area. In this case, the OLT may periodically receive a registration request for a new ONU.

② Upon receiving the registration request for the new ONU, the OLT can broadcast a serial number request message downstream at the time when the quiet window is applied for registration of the new ONU.

③ When a new, unregistered ONU receives a serial number request message broadcast from the OLT, the new ONU that receives the serial number request message receives a serial number response message after the minimum response time (ResTime) and random delay time (Rand). can be transmitted to the OLT. At this time, existing ONUs already registered ignore and do not respond even if they receive the serial number request message broadcasted from the OLT.

④ When the OLT receives the serial number response message from the new ONU, it can transmit an ONU-ID assignment message that can identify the new ONU. In addition, the new ONU may store the assigned ONU-ID if the serial number included in the ONU-ID assignment message is the same as its own serial number.

⑤ The OLT may transmit a distance measurement message for each new ONU in order to calibrate the distance of the newly discovered ONUs. Further, the time until the distance measurement response message is received for each new ONU may be measured. When the distance measurement is completed, the OLT may transmit a correction time equal to the amount obtained by subtracting the measured time from 250 μs to each new ONU through a correction time allocation message. The ONU allocated the calibration time through the calibration time assignment message completes registration and can operate in a normal mode.

⑥ Uplink data of ONUs operating in normal mode after registration is completed always arrives at the OLT after 250 μs.

However, as mentioned above, recent network operators are trying to accommodate 5G mobile fronthaul and backhaul services through next-generation TDMA-PON technology. In particular, to accommodate mobile fronthaul services, latency within 150 μs must be guaranteed in the PON section. .

Therefore, the present invention provides a control method for registering new ONUs by dividing the existing 250 μs quiet window period into multiple quiet window periods of short period according to distance information of new ONUs in order to guarantee a delay time of 150 μs required for fronthaul service. additionally presented.

2 is a diagram illustrating a method of discovering a new ONU by dividing a service area into a plurality of virtual zones according to an embodiment of the present invention.

The new ONU registration method performed by the OLT of the present invention divides a service area into a plurality of virtual areas according to a radius as shown in FIG. 2 to ensure a short delay time of 150 μs or less, and Based on this, the size of the quiet window can be adjusted.

More specifically, the OLT may classify service areas into a plurality of virtual zones based on distances to a plurality of new ONUs. For example, the OLT may classify virtual areas every 5km or 10km to discover and register ONUs existing in a service area of up to 20km.

At this time, when the service area is divided every 5 km, the OLT can discover and register new ONUs existing from 0 km to 20 km by opening a quiet window of a 62.5 μs section four times. As another example, when the service area is divided every 10 km, the OLT may open a quiet window of 125 μs twice to discover and register new ONUs existing from 0 km to 20 km. If the maximum serviceable radius of the OLT is within 10 km, the OLT can discover and register new ONUs by opening a Quiet Window of 125 μs once.

The virtual area of the ONU may be determined through an Optical Time-Domain Reflectometer (OTDR) method or an Optical Distribution Network (ODN) map. Alternatively, the ONU installer can determine the virtual area based on the distance between the OLT and the ONU. Alternatively, the virtual area of the ONU can be divided by the actual maximum service radius of the PON, and by providing multiple quiet windows or a single quiet window in conjunction with the number of divided virtual areas, short delay time while discovering and registering a new ONU can guarantee

3 and 4 are diagrams illustrating a procedure of discovering and registering a new ONU using multiple quiet windows.

① First, the OLT may receive a registration request for a new ONU existing in the service area. In this case, the OLT may periodically receive a registration request for a new ONU.

② Upon receiving the registration request for the new ONU, the OLT can broadcast a serial number request message downstream at the time when the quiet window is applied for registration of the new ONU. At this time, the serial number request message may include an Alloc-ID value that is an identifier capable of classifying a service area into a plurality of virtual areas. In addition, the ONU may include an identification value indicating which virtual area among the service areas it is included in during the initial installation process.

Referring to FIG. 3 , the OLT may broadcast a serial number request message including an Alloc-ID value capable of identifying the first virtual zone in order to discover and register new ONUs existing in the first virtual zone Zone1. can To this end, as shown in FIG. 3 , the OLT may stop (Halt) band allocation of existing ONUs already in service in the cycle period following the request for registration of the new ONU.

③ When a new ONU located in the first virtual area receives the broadcast serial number request message, the new ONU that receives the serial number request message receives the serial number after the minimum response time (ResTime) and random delay time (Rand). A response message may be transmitted to the OLT. On the other hand, new ONUs located in the second virtual area and already registered existing ONUs ignore the serial number request message broadcasted from the OLT and do not respond.

④ When the OLT receives the serial number response message from the new ONU located in the first virtual area, it may transmit an ONU-ID assignment message capable of identifying the new ONU. In addition, the new ONU located in the first virtual area may store the assigned ONU-ID if the serial number included in the ONU-ID assignment message is the same as its own serial number.

⑤ The OLT may transmit a distance measurement message for each new ONU in order to calibrate a distance between newly discovered ONUs located in the first virtual area. In addition, the correction time determined by measuring the time until the distance measurement response message is received for each new ONU may be transmitted to each new ONU through a correction time assignment message. The ONU allocated the calibration time through the calibration time assignment message completes registration and can operate in a normal mode.

⑥ In order to discover and register new ONUs existing in the second virtual zone (Zone1), the OLT may broadcast a serial number request message including an Alloc-ID value capable of identifying the second virtual zone. To this end, as shown in FIG. 4 , the OLT may stop (Halt) bandwidth allocation of existing ONUs already in service in the second cycle period following a request for registration of a new ONU. That is, there may be a time interval of 250 μs between the Hlat command and the Quiet Window.

⑦ When a new ONU located in the second virtual area receives the serial number request message broadcasted, the new ONU that receives the serial number request message receives the serial number after the minimum response time (ResTime) and random delay time (Rand). A response message may be transmitted to the OLT. On the other hand, new ONUs located in the first virtual area and already registered existing ONUs ignore the serial number request message broadcasted from the OLT and do not respond.

⑧ When the OLT receives a serial number response message from a new ONU located in the second virtual area, it may transmit an ONU-ID assignment message capable of identifying the new ONU. In addition, the new ONU located in the second virtual area can store the assigned ONU-ID if its own serial number is the same as the serial number included in the ONU-ID assignment message.

⑨ The OLT may transmit a distance measurement message for each new ONU in order to calibrate a distance between newly discovered ONUs located in the second virtual area. In addition, the correction time determined by measuring the time until the distance measurement response message is received for each new ONU may be transmitted to each new ONU through a correction time assignment message. The ONU allocated the calibration time through the calibration time assignment message completes registration and can operate in a normal mode.

In this way, the OLT of the present invention divides the service area of the PON into a plurality of virtual areas, and adjusts the size of the quiet window based on the number of the divided virtual areas to ensure a short delay time and achieve fronthaul through high transmission efficiency. It can provide service acceptance and ultra-low latency service.

Meanwhile, the method according to the present invention is written as a program that can be executed on a computer and can be implemented in various recording media such as magnetic storage media, optical reading media, and digital storage media.

Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or combinations thereof. Implementations may be a computer program product, i.e., an information carrier, e.g., a machine-readable storage, for processing by, or for controlling, the operation of a data processing apparatus, e.g., a programmable processor, computer, or plurality of computers. It can be implemented as a computer program tangibly embodied in a device (computer readable medium) or a radio signal. A computer program, such as the computer program(s) described above, may be written in any form of programming language, including compiled or interpreted languages, and may be written as a stand-alone program or in a module, component, subroutine, or computing environment. It can be deployed in any form, including as other units suitable for the use of. A computer program can be deployed to be processed on one computer or multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

Processors suitable for processing a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from read only memory or random access memory or both. Elements of a computer may include at least one processor that executes instructions and one or more memory devices that store instructions and data. In general, a computer may include, receive data from, send data to, or both, one or more mass storage devices that store data, such as magnetic, magneto-optical disks, or optical disks. It can also be combined to become. Information carriers suitable for embodying computer program instructions and data include, for example, semiconductor memory devices, for example, magnetic media such as hard disks, floppy disks and magnetic tapes, compact disk read only memory (CD-ROM) ), optical media such as DVD (Digital Video Disk), magneto-optical media such as Floptical Disk, ROM (Read Only Memory), RAM (RAM) , Random Access Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and the like. The processor and memory may be supplemented by, or included in, special purpose logic circuitry.

In addition, computer readable media may be any available media that can be accessed by a computer, and may include both computer storage media and transmission media.

Although this specification contains many specific implementation details, they should not be construed as limiting on the scope of any invention or what is claimed, but rather as a description of features that may be unique to a particular embodiment of a particular invention. It should be understood. Certain features that are described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable subcombination. Further, while features may operate in particular combinations and are initially depicted as such claimed, one or more features from a claimed combination may in some cases be excluded from that combination, and the claimed combination is a subcombination. or sub-combination variations.

Similarly, while actions are depicted in the drawings in a particular order, it should not be construed as requiring that those actions be performed in the specific order shown or in the sequential order, or that all depicted actions must be performed to obtain desired results. In certain cases, multitasking and parallel processing can be advantageous. Further, the separation of various device components in the embodiments described above should not be understood as requiring such separation in all embodiments, and the program components and devices described may generally be integrated together into a single software product or packaged into multiple software products. You have to understand that you can.

On the other hand, the embodiments of the present invention disclosed in this specification and drawings are only presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. In addition to the embodiments disclosed herein, it is obvious to those skilled in the art that other modified examples based on the technical idea of the present invention can be implemented.

Claims (8)

In the method of registering a new optical network unit (ONU) performed by an optical line terminal (OLT),
periodically receiving a registration request of a new ONU existing in the service area;
if the registration request for the new ONU is received in a first cycle period, stopping allocation of bandwidth to ONUs currently in service in a second cycle period immediately after the first cycle period;
broadcasting a serial number request message for registration of a new ONU existing in the service area in a third cycle period immediately after the cycle period in which the uplink data transmission is completed, when uplink data transmission of the currently serving ONUs is completed; ; and
registering the new ONU that sent the serial number response message when a serial number response message is received from the new ONU in response to the serial number request message;
including,
The broadcasting step is
The new ONU registration method of dividing the service area into a plurality of virtual areas according to a radius and broadcasting the serial number request message by adjusting the size of a quiet window based on the number of the divided virtual areas. According to claim 1,
The serial number request message,
An identifier for distinguishing a service area divided into a plurality of virtual areas according to the radius,
The new ONU existing in the service area,
A method for registering a new ONU in which a serial number response message is transmitted to the OLT in response to a serial number request message including an identifier corresponding to its location. According to claim 1,
The new ONU,
The new ONU registration method of transmitting a serial number response message to the OLT after a minimum response time and a random delay time when receiving a serial number request message from the OLT. According to claim 1,
In the step of registering the new ONU,
allocating an identifiable ID to a new ONU that has transmitted the serial number response message; and
Completing registration of the new ONU by measuring a distance to the new ONU to which the ID is assigned and allocating a correction value thereto
A new ONU registration method including. In an optical line terminal (OLT),
processor
including,
the processor,
ONUs that periodically receive registration requests for new ONUs existing in the service area, and are currently serving in the second cycle period immediately after the first cycle period when the registration request for the new ONU is received in the first cycle period Band allocation is stopped, and when the uplink data transmission of the ONUs currently in service is completed, a serial number for registering a new ONU existing in the service area in the third cycle period immediately after the cycle period in which the uplink data transmission is completed. broadcasting a number request message, and when a serial number response message is received from the new ONU in response to the serial number request message, registering the new ONU that has transmitted the serial number response message;
The optical fiber terminal for broadcasting the serial number request message by dividing the service area into a plurality of virtual areas according to a radius and adjusting the size of a quiet window based on the number of the divided virtual areas. According to claim 5,
The serial number request message,
An identifier for distinguishing a service area divided into a plurality of virtual areas according to the radius,
The new ONU existing in the service area,
An optical line terminal that transmits a serial number response message to the OLT in response to a serial number request message including an identifier corresponding to its location. According to claim 5,
The new ONU,
An optical fiber terminal for transmitting a serial number response message to the OLT after a minimum response time and a random delay time when receiving a serial number request message from the OLT. According to claim 5,
the processor,
An optical fiber that completes the registration of the new ONU by assigning an identifiable ID to the new ONU that has transmitted the serial number response message, measuring the distance to the new ONU to which the ID is assigned, and allocating a correction value. Terminal.

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