KR20210064748A - Method for registering a new optical network unit in a passive optical network and an optical line terminal performing the same - Google Patents

Abstract

Disclosed are a method for registering a novel optical network unit in a passive optical network and an optical line terminal performing the same. The method for registering a novel optical network unit, performed by an optical line terminal, comprises the steps of: periodically receiving a registration request of a novel ONU existing in a service area; stopping, when the registration request of the novel ONU is received in a first cycle period, bandwidth allocation for ONUs being currently serviced in a second cycle period immediately after the first cycle period; broadcasting, when the uplink data transmission of the ONUs being currently serviced is completed, a serial number request message for registration of the novel ONU existing in the service area in a third cycle period immediately after the cycle period in which the uplink data transmission is completed; and registering, when a serial number response message is received from the novel ONU in response to the serial number request message, the novel ONU which has transmitted the serial number response message. In the step of broadcasting, the service area is divided into a plurality of virtual areas in accordance with a radius, and the size of a quiet window is adjusted based on the number of the divided virtual areas such that the serial number request message may be broadcast. In accordance with the present invention, the device can ensure a short delay time while discovering and registering new ONUs.

Description

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

In order to accommodate a fronthaul service that requires a latency of 150 μs in a passive optical network (PON), the present invention subdivides a quiet window of 250 μs to provide a new optical network unit (Optical Network). Unit, ONU).

Time Division Multiple Access (TDMA) Passive optical network technology (TDMA-PON) allows one Optical Line Terminal (OLT) and multiple ONUs to be connected to a point-to-multipoint It is configured in a (Point-to-Multipoint) connection method. Therefore, the TDMA-PON technology transmits a signal in a broadcast method downlink, and transmits a signal in a burst method uplink.

In the conventional TDMA-PON technology, a quiet window of 250 μs period is used for registration of a new ONU. This is the time to discover ONUs that exist at a distance of at least 0 km and at a maximum of 20 km. Therefore, at this time, the uplink band is not allocated in advance two cycles before the normally registered ONUs from transmitting data. That is, for the quiet window period, the OLT can be registered without colliding with signals of ONUs that have not yet been discovered by controlling the ONUs already in service not to transmit data.

However, recently, network operators are trying to accommodate 5G mobile fronthaul and backhaul services through next-generation TDMA-PON technology. In particular, in order to accommodate the mobile fronthaul service, a delay time within 150 μs must be guaranteed in the PON section. However, in the conventional TDMA-PON technology, a quiet window period of 250 μs is used for discovery and registration of a new ONU, and as a result, the ONUs that are already registered and in service have a delay time of 250 μs.

Therefore, there is a need for a method of controlling a quiet window that can guarantee low delay in order to accommodate the mobile fronthaul service in the conventional TDMA-PON technology.

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

A new optical network unit (ONU) registration method performed by an optical line terminal (OLT) according to an embodiment of the present invention includes periodically receiving a registration request of a new ONU existing in a service area. step; stopping bandwidth allocation to ONUs currently serving in a second cycle period immediately after the first cycle period when the registration request of the new ONU is received in 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 the 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 a new ONU that has transmitted the serial number response message, wherein the broadcasting includes a radius of the service area. The serial number request message may be broadcast by dividing a plurality of virtual regions according to the method and adjusting the size of a quiet window based on the number of the divided virtual regions.

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

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

The registering of 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 assigning a correction value.

An optical line terminal (OLT) according to an embodiment of the present invention includes a processor, wherein the processor periodically receives a registration request of a new ONU existing in a service area, and receives the registration request of the new ONU In case of reception 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 Broadcast a serial number request message for registration of a new ONU existing in the service area in the third cycle period immediately after the cycle period in which data transmission is completed, and a serial number response message from the new ONU in response to the serial number request message is received, registers a new ONU that has transmitted the serial number response message, divides the service area into a plurality of virtual areas according to a radius, and performs a quiet window based on the number of the divided virtual areas. By adjusting the size of , the serial number request message can be broadcast.

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

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

The processor assigns an identifiable ID (ID) to the new ONU that has transmitted the serial number response message, measures the distance to the new ONU to which the ID is assigned, and assigns a correction value to complete the registration of the new ONU can do.

The present invention divides the service area into a plurality of virtual areas according to the distance or installation information of the ONUs measured in advance, and adjusts the size of the quiet window based on the number of the divided virtual areas to discover and register new ONUs while maintaining a short The delay time 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 for discovering and registering a new ONU using a multi-quiet window.

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.

FIG. 1 shows an example in which the OLT applies a quiet window of 250 μs period to discover new ONUs existing in a service area of a minimum distance of 0 km to a maximum of 20 km. The 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 may broadcast a serial number request message downward at the time when a 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 receiving the serial number request message sends a serial number response message after the minimum response time (ResTime) and random delay time (Rand). It can be transmitted with OLT. At this time, the existing ONUs that have already been registered ignore the serial number request message broadcast from the OLT and do not respond.

④ When the OLT receives the serial number response message from the new ONU, the OLT may transmit an ONU-ID assignment message for identifying the new ONU. In addition, if the serial number included in the ONU-ID assignment message and its own serial number are the same, the new ONU may store the assigned ONU-ID.

⑤ The OLT may transmit a distance measurement message for each new ONU in order to correct the distances of the newly discovered ONUs. In addition, time can be measured until a distance measurement response message is received for each new ONU. When the distance measurement is completed, the OLT can transmit a correction time equal to 250 μs minus the measured time to each new ONU through a correction time assignment message. The ONU assigned the calibration time through the calibration time assignment message is registered and can operate in the normal mode.

⑥ Upstream 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 want to accommodate 5G mobile fronthaul and backhaul services through next-generation TDMA-PON technology. In particular, in order to accommodate mobile fronthaul services, a delay time of less than 150μs in the PON section must be guaranteed. .

Therefore, the present invention divides the existing 250 μs quiet window section into multiple quiet window sections of a short period according to the distance information of the new ONUs in order to guarantee the 150 μs delay time required for the fronthaul service. A control method for registering new ONUs. 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 the service area into a plurality of virtual areas according to the radius as shown in FIG. 2 in order to ensure a short delay time within 150 μs, and depends on the number of divided virtual areas. Based on this, the size of the silent window can be adjusted.

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

In this case, when the OLT divides the service area every 5 km, it can open a quiet window of 62.5 μs section 4 times to discover and register new ONUs existing from 0 km to 20 km. As another example, when the OLT divides the service area every 10 km, it can discover and register new ONUs existing from 0 km to 20 km by opening a quiet window of 125 μs twice. If the maximum service radius that can be serviced by the OLT is within 10 km, the OLT can discover and register new ONUs by opening a 125 μs Quiet Window once.

Such a 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 may 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 virtual areas divided in this way, a new ONU is discovered and registered while short delay time can guarantee

3 and 4 are diagrams illustrating a procedure for discovering and registering a new ONU using a multi-quiet window.

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 may broadcast a serial number request message downward at the time when a quiet window is applied for registration of the new ONU. In this case, the serial number request message may include an Alloc-ID value, which is an identifier for classifying a service area into a plurality of virtual areas. In addition, the ONU may include an identification value for which virtual area of the service area it is included in during the initial installation process.

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

③ When the new ONU located in the first virtual area receives the broadcast serial number request message, the new ONU receiving the serial number request message responds with the serial number after the minimum response time (ResTime) and random delay time (Rand) Messages can be sent to the OLT. On the other hand, new ONUs located in the second virtual area and existing ONUs already registered ignore the serial number request message broadcast from the OLT and do not respond.

④ When the OLT receives a serial number response message from the new ONU located in the first virtual area, the OLT may transmit an ONU-ID assignment message for 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 and its own serial number are the same.

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

⑥ The OLT may broadcast a serial number request message including an Alloc-ID value for identifying the second virtual area in order to discover and register new ONUs existing in the second virtual area Zone1. To this end, the OLT may stop allocating bands of existing ONUs already in service in the second cycle period after registration of a new ONU is requested as shown in FIG. 4 . That is, there may be a time interval of 250 μs between the Hlat command and the quiet window.

⑦ When the new ONU located in the second virtual area receives the broadcast serial number request message, the new ONU receiving the serial number request message responds with the serial number after the minimum response time (ResTime) and random delay time (Rand) Messages can be sent to the OLT. On the other hand, new ONUs located in the first virtual area and existing ONUs already registered ignore the serial number request message broadcast from the OLT and do not respond.

⑧ When the OLT receives a serial number response message from the new ONU located in the second virtual area, the OLT may transmit an ONU-ID assignment message for identifying the new ONU. In addition, the new ONU located in the second virtual area may store the assigned ONU-ID when the serial number included in the ONU-ID assignment message and its own serial number are the same.

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

As described above, the OLT of the present invention divides the service area of the PON into a plurality of virtual areas, adjusts the size of the quiet window based on the number of divided virtual areas, thereby guaranteeing a short delay time, and fronthauling through high transmission efficiency. It can accommodate service and provide 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 implemented for processing by, or for controlling the operation of, a data processing device, eg, a programmable processor, computer, or number of computers, a computer program product, ie an information carrier, eg, a machine readable storage It may be embodied as a computer program tangibly embodied in an apparatus (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, as a standalone program or in a module, component, subroutine, or computing environment. It can be deployed in any form, including as other units suitable for use in A computer program may be deployed to be processed on one computer or multiple computers at one site or to be distributed across multiple sites and interconnected by a communications 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. In general, 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 one or more mass storage devices for storing data, for example magnetic, magneto-optical disks, or optical disks, receiving data from, sending data to, or both. may be combined to become Information carriers suitable for embodying computer program instructions and data are, 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 recording media such as DVD (Digital Video Disk), magneto-optical media such as optical disk, ROM (Read Only Memory), RAM (RAM) , Random Access Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and the like. Processors and memories may be supplemented by, or included in, special purpose logic circuitry.

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

While this specification contains numerous specific implementation details, they should not be construed as limitations on the scope of any invention or claim, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. should be understood Certain features that are described herein in the context of separate embodiments may be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments, either individually or in any suitable subcombination. Furthermore, although features operate in a particular combination and may be initially depicted as claimed as such, one or more features from a claimed combination may in some cases be excluded from the combination, the claimed combination being a sub-combination. or a variant of a sub-combination.

Likewise, although acts are depicted in the drawings in a particular order, it should not be construed that all acts shown must be performed or that such acts must be performed in the specific order or sequential order shown to achieve desirable results. In certain cases, multitasking and parallel processing may be advantageous. Further, the separation of the various device components of the above-described embodiments should not be construed 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 the present specification and drawings are merely presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. It will be apparent to those of ordinary skill in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

Claims (8)

In a new optical network unit (ONU) registration method performed by an optical line terminal (OLT),
periodically receiving a registration request of a new ONU existing in a service area;
stopping bandwidth allocation to ONUs currently serving in a second cycle period immediately after the first cycle period when the registration request of the new ONU is received in a 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 the 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 a new ONU that has transmitted the serial number response message;
including,
The broadcasting step is
A new ONU registration method 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 1,
The serial number request message is
an identifier for classifying a service area divided into a plurality of virtual areas according to the radius;
The new ONU existing in the service area,
A new ONU registration method for transmitting 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 1,
The new ONU is
When a serial number request message is received from the OLT, a new ONU registration method for transmitting a serial number response message to the OLT after a minimum response time and a random delay time. According to claim 1,
The step of registering the new ONU comprises:
allocating an identifiable ID (ID) to a new ONU that has transmitted the serial number response message; and
Completing the registration of the new ONU by measuring the distance to the new ONU to which the ID is assigned and assigning a correction value
A new ONU registration method, including In the optical line terminal (Optical Line Terminal, OLT),
processor
including,
The processor is
When a registration request of a new ONU existing in the service area is periodically received and the registration request of the new ONU is received in the first cycle period, ONUs currently in service in the second cycle period immediately after the first cycle period When the uplink data transmission of the ONUs currently in service is completed, the serial for registration of 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 Broadcast a number request message, and when a serial number response message is received from a new ONU in response to the serial number request message, register a new ONU that has transmitted the serial number response message;
An optical line 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. 6. The method of claim 5,
The serial number request message is
an identifier for classifying 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 for transmitting a serial number response message to the OLT in response to a serial number request message including an identifier corresponding to its location. 6. The method of claim 5,
The new ONU is
When the serial number request message is received from the OLT, the optical line terminal transmits the serial number response message to the OLT after a minimum response time and a random delay time. 6. The method of claim 5,
The processor is
An optical line that completes the registration of the new ONU by allocating an identifiable ID (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 assigning a correction value terminal.

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