METHOD AND APPARATUS FOR IDENTIFICATION OF TERMINAL MODULES IN PASSIVE OPTICAL NETWORKS FOR OCCUPANCY STATUS DETECTION

Description

1 / 14 METHOD AND APPARATUS FOR IDENTIFICATION OF TERMINAL MODULES IN PASSIVE OPTICAL NETWORKS FOR OCCUPANCY STATUS DETECTION

[001] The present invention relates to a method and apparatus for identifying terminal equipment in a Passive Optical Network (PON) in order to detect the occupancy status of a customer service optical fiber. More specifically, the invention deals with the identification of connected transmission and reception equipment through the detection of upstream optical signal power, allowing efficient monitoring and management of optical fiber utilization in PON networks. FIELD OF APPLICATION

[002] This invention applies to the telecommunications sector, focusing on optical network infrastructure, more specifically passive optical networks, which are widely used to provide high-capacity data transmission services (e.g., internet, television, and telephony) over optical fiber directly to homes and businesses. The proposed method is particularly relevant for network operators, Internet Service Providers (ISPs), and other agents who need an efficient solution for monitoring, identifying, and managing equipment connected to a PON. The application of this method allows for the detection of the occupancy status of optical fibers, essential for proactive maintenance, optimization of network performance, and ensuring the continuity of services provided to end users.Furthermore, the invention can be applied in scenarios where rapid identification of connection problems or optical fiber failures is necessary, facilitating corrective interventions and minimizing network downtime. This innovation is relevant both to existing PON networks and to future expansions and technological evolutions in the field of optical networks, such as XGS-PON (10 Gigabit Symmetrical Passive Optical Network) and NG-PON2 (Next Generation Passive Optical Network 2), where efficient management and monitoring of network integrity remain critical challenges. Petition 870240110269, dated 12 / 26 / 2024, page 6 / 51 2 / 14

[003] Within this context, two main application scenarios for the invention are foreseen. In the first, if the developed device is placed on the primary side of the splitter, i.e., on the OLT (Optical Line Terminal) side, after calibrating a reference power signal, the user must remove the connectors on the secondary side, one by one, checking if there is a decrease in the power of one of the signals compared to the reference value. The decrease in power will indicate the presence of an ONT (Optical Network Terminal) or ONU (Optical Network Unit) connected to the port that was disconnected. On the other hand, if no variation occurs, this means that the port is available and a new device can be connected.

[004] In the second anticipated application scenario, if the developed device is placed on the secondary side of the splitter, i.e., on the ONT or ONU side, the user must identify the presence of optical power. If this is verified, it means that there is an ONT / ONU connected to that port of the splitter. If there is no power, assuming the connections are adequate, the port is available. OBJECTIVE OF THE INVENTION

[005] The present invention aims to develop an innovative and efficient method and apparatus for identifying equipment connected to PON networks and for detecting the occupancy status of optical fibers. In PON networks, the management and monitoring of terminal equipment and optical fibers are necessary to ensure service continuity and optimize available resources. However, field technicians have great difficulty in identifying whether a given service fiber has an associated customer or not. In the current scenario, when a technician encounters an optical fiber, it is not uncommon for them to lack accurate information about the occupancy status of that fiber, leading to difficulties in maintenance, installation, and troubleshooting of connection problems. This invention seeks to provide a practical and efficient solution to overcome this challenge, allowing technicians to obtain this information quickly and reliably.

[006] The proposed method allows the technician, upon connecting the measuring apparatus, to immediately identify whether there is an active terminal device, such as an ONU or ONT, on that specific fiber. This is achieved by measuring the optical power of the signal. Petition 870240110269, dated 12 / 26 / 2024, p. 7 / 51 3 / 14 upstream, which provides a clear indication of the fiber occupancy status. With this information, the technician can make informed decisions, such as proceeding with an installation, performing preventive maintenance, or quickly identifying the cause of a service outage.

[007] In addition to identifying connected devices, the invention also allows the field technician to detect the state of the optical fiber in terms of its integrity and transmission capacity. By analyzing the signal strength, the technician can verify whether the fiber is functioning correctly or if there are problems such as excessive attenuation or transmission failures, which could compromise customer service. This real-time diagnostic capability ensures that the fiber is in perfect condition before any intervention.

[008] Another important aspect of the invention is its ease of use and integration with established work procedures for the maintenance and installation of passive optical networks. The method was developed to be intuitive, allowing technicians with different levels of experience to use it effectively. The information collected in the field can be used to update the operator's records, facilitating the management and documentation of the activities performed. By monitoring and analyzing the status of the optical fibers and connected devices, operators can ensure that the network is not being underutilized or overloaded at any point. This optimization is essential to ensure that all network resources are being used efficiently, which is particularly important in high-demand network environments, such as those found in densely populated urban areas. PROBLEM TO BE SOLVED

[009] The central problem that this invention aims to solve is the lack of accurate, real-time information for field technicians about the occupancy status and integrity of optical fibers in PON networks. In many situations, technicians are faced with the need to quickly identify whether a specific service fiber is connected to an active terminal device, such as an ONU or ONT, and whether that connection is operating within the appropriate parameters. Petition 870240110269, dated 12 / 26 / 2024, page 8 / 51 4 / 14

[010] Currently, the methods available for this verification are often inadequate, time-consuming, or require additional complex equipment, which can result in inaccurate diagnoses and delays in maintenance, installation, and troubleshooting operations. This lack of visibility not only impacts operational efficiency but can also lead to underutilization of the network or, in extreme cases, interruption of customer service.

[011] Another aspect of the problem involves the difficulty in detecting the integrity status of the optical fiber. Fibers that exhibit degradation or faults may continue to operate, but with suboptimal performance, compromising service quality without the field technician having an adequate tool to quickly and accurately identify these anomalies. The absence of an effective method for monitoring and diagnosing fiber status compromises the ability of network operators to guarantee service continuity and quality.

[012] In this context, the invention aims to solve these problems by providing a method and apparatus that allow, through the upstream signal power level, the real-time identification of connected equipment and the detection of the occupancy and integrity status of the optical fiber, directly in the field. This provides technicians with the information necessary to perform their tasks with greater precision and efficiency, ensuring the maintenance of service quality in a PON network. STATE OF THE ART

[013] PON networks are widely used to provide telecommunications services, including broadband internet, television, and telephony. In a PON, a single optical fiber is shared among multiple end users for bidirectional transmission of downstream and upstream signals. Therefore, monitoring and managing the use of this fiber aims to ensure service quality and efficient network maintenance. To this end, several techniques are proposed in the literature for managing fiber optic occupancy. Usually, monitoring ONTs and ONUs in modern optical networks uses advanced Network Management Systems (NMS) and protocols such as the Optical Network Unit Management Control Interface (OMCI). Petition 870240110269, dated 12 / 26 / 2024, page 9 / 51 5 / 14 combining real-time analytics and machine learning algorithms to predict failures and optimize performance. Additionally, current networks apply predictive diagnostics and big data for proactive maintenance and automated provisioning, ensuring high reliability and efficiency.

[014] However, in many cases, data on the occupancy status of optical fibers and equipment in the field is outdated, leading to significant problems during the installation of new equipment. When technicians install new equipment, the lack of accurate information can result in the accidental disconnection of an occupied fiber, causing service interruption for an existing customer. Furthermore, after a customer's contract ends, it is common for the fiber to the customer's home to be left connected, creating confusion about whether the fiber is actually in use. This makes it difficult for technicians to accurately identify which ports are available to serve new customers, increasing the risk of errors and service interruptions. In such a context, the use of NMS and OMCI-based equipment is complex and costly, not offering a scalable and low-cost solution for constant use by multiple distributed field teams.

[015] In order to overcome this limitation, there are some patent documents and scientific articles that describe techniques, methods and instruments for monitoring ONTs / ONUs connected to the network. However, as will be detailed later, none of these documents describes the configuration and method proposed in this patent. Among these documents, the following stand out:

[016] The patent document EP2579524A1 “Method and System for Identifying 'Accessing Network for Home Gateway' provides a method and system for identifying and accessing a Home Gateway (HG) network. The process involves an ONU that receives the HG's MAC address and a management VLAN resource code sent by a network manager. The ONU automatically identifies the HG connected to it by associating the MAC address and management VLAN, and then reports this data to the network manager. After confirmation of access to the HG network by a resource system, the manager configures the ONU's access identifier and sends service VLAN translation rules. The ONU, in turn, translates the Petition 870240110269, dated 12 / 26 / 2024, page 10 / 51 6 / 14 The HG's VLANs are placed within a recognized service VLAN, allowing for automatic identification and network access for the HG. Conversely, the method and apparatus proposed here offer a low-cost and low-complexity solution for field monitoring of such systems, if based on optical power measurement techniques rather than packet identification in communication protocols.

[017] Patent document US7907843 “Technique of Identifying a Defective Subscriber Device in a Point-to-Multipoint Network Without Stopping Normal Subscriber Devices” describes a method for identifying a defective ONU in a point-to-multipoint network, composed of an OLT and multiple ONUs. Since in PON systems each ONU can only send signals during a specific period of time, the presented technique proposes that the OLT measures the optical reception level of the signal for each period and stores these levels in a table, associating them with each ONU. Under normal conditions, the ONU signals are received without collisions, so the OLT compares the measured reception levels with the stored levels to determine if an ONU signal was received exclusively or if there was a collision. If an ONU signal is not received exclusively, the OLT identifies the defective ONU by comparing the measured reception level with the stored level associated with the corresponding time period.As mentioned, this prior art solves the problem of interference caused by defective ONUs transmitting outside permitted periods, ensuring service continuity for other network users. In contrast, the method and apparatus proposed in the present invention aim to solve the problem of a lack of accurate field information about the occupancy status of optical fibers and the presence of connected devices, facilitating maintenance and troubleshooting, and are fundamentally different from the prior art presented.

[018] In turn, patent document US7916983B2 “Signal Identifying Apparatus for an Optical Fiber” aims to develop a device capable of detecting and identifying high-transmission-rate signals, such as upstream and downstream signals, in an optical fiber, without interrupting traffic or disconnecting the fibers. The device separates and isolates the desired signal using adjustable filters, facilitating monitoring and maintenance in Petition 870240110269, dated 12 / 26 / 2024, page 11 / 51 7 / 14 Passive Optical Networks. As mentioned, the prior art focuses on the separation and identification of high-speed transmission signals in PON networks, aiming to maintain service integrity and continuity, based on protocol-level techniques of the transmitted signals. In contrast, the method and apparatus proposed here are focused on facilitating fieldwork and improving the detection of connected equipment through monitoring the optical power of the upstream signal, as well as allowing monitoring of the installed fiber status, fundamentally differing from the prior art presented.

[019] Complementarily, patent document US 9432114B2 Method for Identifying the Optical Network Unit Power Off Reason addresses a system and method in passive optical networks for identifying the reasons for power loss in optical network units. The invention involves detecting power-off scenarios and transmitting a message indicating the reason for the power loss, such as manual shutdown by a subscriber, external power failure, or internal circuit faults. This allows the network to differentiate between intentional shutdowns and actual power failures, improving the response and management of network components. As mentioned, the prior art focuses on providing information about the reason for ONU shutdowns to the network management system.In contrast, the method and apparatus proposed here aim to provide a practical and easy-to-use solution for field technicians, focusing on identifying connected devices by monitoring the optical power of the upstream signal and verifying the status of the optical fiber to ensure the efficiency and continuity of service, being fundamentally different from the previously presented approach.

[020] Patent document US20120008939A1, “Method for Identifying an Optical Network Unit and an Optical Access System and Device,” addresses a method for identifying ONUs in an optical access system. The main focus is the automatic identification of ONUs based on point-to-point (P2P) connections that have been erroneously connected in an optical access system based on point-to-multipoint (P2MP) connections, such as PON systems. The method involves receiving upstream signals sent by multiple ONUs through a path of Petition 870240110269, dated 12 / 26 / 2024, p. 12 / 51 8 / 14 shared optical transmission, extraction of detection signals from these upstream signals, and obtaining characteristics of the detection signal. These characteristics are then compared to a reference value to determine if a P2P ONU is connected in the system. If a P2P ONU is incorrectly identified in a P2MP system, a fault alarm is quickly generated to facilitate system maintenance and troubleshooting. As mentioned, the prior art focuses on detecting and correcting problems with P2P ONUs incorrectly connected in P2MP systems, with an emphasis on automatic detection and prevention of system interference.In contrast, the method and apparatus proposed here focus on providing a practical solution for field technicians to identify connected devices by monitoring the optical power of the upstream signal, as well as allowing verification of the optical fiber's condition, and are fundamentally different from the previously presented approach.

[021] In turn, patent document WO2021098330A1 Method for Identifying Optical Network Units, Apparatuses, and System addresses a method for identifying optical network units, devices, and systems in an optical access network. The method may include the measurement and analysis of optical signals, as well as the detection of the status of connected equipment, to improve network management and maintenance. The objective is to ensure that the network operates efficiently, reducing problems such as connection failures and identifying possible configuration or installation errors. As mentioned, the prior art solves the problem of automatic identification and continuous evaluation of devices connected to the PON network, ensuring that the network operates without anomalies or connectivity failures. In contrast, the method and apparatus proposed here are focused on offering a solution for field operation, based exclusively on optical power level information of the signals.

[022] Finally, patent document WO2009008869A1 Method and Apparatus for Managing Optical Network Units describes a system and method for monitoring and managing devices in passive optical networks, such as ONUs and ONTs. The objective is to ensure the correct operation of connected devices and to quickly identify network faults, using optical signals to detect and diagnose problems, optimizing Petition 870240110269, dated 12 / 26 / 2024, page 13 / 51 9 / 14 thus the maintenance and performance of the network. As mentioned, the prior art addresses a more comprehensive and automated solution for the continuous management and monitoring of devices through parameters encapsulated in the PON network communication protocol. In contrast, the method and apparatus proposed here are focused on providing a solution for field operation, based exclusively on optical power level information of the signals. DESCRIPTION OF THE FIGURES

[023] The following figures illustrate the operation and preferred method of implementation of the invention, aiming to allow continuous and real-time measurement of the optical signal power in a PON network, without causing interruptions in the data flow and thus guaranteeing the integrity and quality of the transmitted signal.

[024] Figure 1 illustrates a schematic of a traditional passive optical network with an optical splitter to serve N clients (ONTs / ONUs) from a single OLT (001). The identified fiber optic cable (100) provides the input signal to the optical splitter (020), which is responsible for dividing the input signal into multiple signals for distribution. Reference (120) indicates one of the output cables that connects the optical splitter to one of the network devices, identified as ONT / ONU.Reference (130) represents another output cable from the splitter, with a dashed line indicating a variation in the configuration, showing that the ONT / ONU does not have a connection. Finally, the ONT / ONU elements (030) represent the terminal units or optical network units that receive the signal split by the optical splitter. The figure shows what a traditional PON network looks like and how optical signals are distributed to multiple network devices through the splitter, with different connection options represented by the solid and dashed lines.

[025] Figure 2 illustrates a passive optical network scheme, presented in Figure 1, in which the invention is positioned on the primary side of the network, i.e., on the OLT side (001), which connects to the invention via the optical fiber cable identified by reference (100). The invention is represented by element (010), located before the optical splitter, identified by reference (020), which is responsible for dividing the signal arriving from the invention into multiple output signals. The outputs of the optical splitter Petition 870240110269, dated 12 / 26 / 2024, page 14 / 51 10 / 14 are indicated by references (120) (solid line) and (130) (dashed line), connecting to multiple network devices identified as ONT / ONU (030). This configuration demonstrates how the invention interacts with the optical signal before its distribution to network devices, emphasizing its role in the primary phase of the PON network, before the optical splitter.

[026] Figure 3 shows a passive optical network scheme, as shown in Figure 1, in which the invention is positioned on the secondary side of the network, on the ONU / ONT side (030). Again, the OLT (001) is connected to the optical splitter, identified by reference (020), by means of an optical fiber cable (100), allowing the signal to be divided into multiple output cables. The invention, represented by element (010), is connected to the splitter on the output side of the splitter, after the signal division. The outputs of the optical splitter are connected to the invention by means of cables identified by numerical reference (120), which then distributes the signals to the ONT / ONU devices (030) installed at each customer. The figure also shows a dashed line representing an alternative or optional configuration, indicated by numerical reference (130).This configuration demonstrates the operation of the invention on the secondary side of the PON network, after the signal has been split by the optical splitter, highlighting its role in the final distribution of the signal to the network devices.

[027] Figure 4 details the internal configuration of the apparatus (010) proposed for the preferred implementation of the invention. The OLT, identified by reference (001) in the previous figures, is connected to the invention by means of the fiber optic cable (100). The optical signal enters the apparatus (010) through the input and output connectors (301), following the path represented by the arrows indicated by (330), which show the direction of the bidirectional flow, containing downstream (340) and upstream (350) signals. Within the invention, the signal is divided into two parallel paths: one path, represented by flow (334), goes towards the central element which is an unbalanced coupler (320), which measures a portion of the optical signal power for monitoring, while the other path goes directly towards the output connector (301) via flow (332).On the path leading to the power meter, the optical signal passes through components called circulators (C) that separate the signal from. Petition 870240110269, dated 12 / 26 / 2024, page 15 / 51 11 / 14 upstream of the downstream signal in the paths identified by (334) and (332), respectively, allowing the signals of interest to be directed to an unbalanced coupler responsible for diverting a small fraction of the upstream signal for measurement without interrupting the main transmission. The power meter (310) is responsible for evaluating the intensity of the optical signal passing through the element (320), being connected to it by the fiber (330) for the signal flow (350), and thus informing the technician whether the fiber is being used for service or not.

[028] Figure 5 presents a flowchart describing the method for verifying and identifying active or available ports in an optical splitter using the apparatus shown in Figure 4 through analysis of the primary side of the network. Initially, the equipment is connected to the primary side of the splitter, where the reference power measurement is performed and then saved. Next, the ports on the secondary side are disconnected sequentially, and, with each disconnection, it is checked whether the reference power has changed: if there is a change, the port is identified as active; otherwise, it is considered available. The active port is reconnected for confirmation and the process is repeated for other ports, if any. The procedure is completed when all ports have been verified.

[029] Figure 6 presents a flowchart describing the method for identifying active or inactive ports in a PON from the secondary side of the splitter using the apparatus shown in Figure 4. The procedure begins with the selection of the port to be tested, followed by the connection of the measuring equipment. After waiting a few seconds for signal stabilization, the optical power detection is checked: if power is detected, the port is considered active; otherwise, it is marked as inactive. Then, the active port is reconnected to confirm the reading. The process is repeated for other ports, if any, until all are tested, ending the procedure. GENERAL DESCRIPTION OF THE INVENTION

[030] The proposed invention consists of a method and apparatus for identifying active and available ports in an optical splitter used for signal distribution in passive optical networks, facilitating the work of field technicians in monitoring. Petition 870240110269, dated 12 / 26 / 2024, p. 16 / 51 12 / 14 and testing of these systems. The method involves connecting the proposed measuring apparatus to the primary or secondary side of the splitter. On the primary side, the equipment performs a reading of the reference optical power, which allows the identification of ports with active equipment connected and those that are available, through the analysis of variations in optical power when ports on the secondary side are disconnected. On the secondary side, the equipment can be used to directly identify active ports, contributing to the flexibility of the process. The invention aims to simplify the process of verifying and documenting connections in PON networks, providing a fast, efficient and intuitive procedure that minimizes errors and improves service quality. The system is capable of storing the information obtained, enabling the updating of network records and contributing to the optimization of maintenance and planning of optical networks. DETAILED DESCRIPTION AND METHOD OF CARRYING OUT THE INVENTION

[031] The proposed invention aims to facilitate the identification of active and available ports in passive optical networks, according to the topology shown in Figure 1, and, for this purpose, employs the apparatus shown in Figure 4. The proposed equipment receives the optical signal from the OLT through an optical fiber and divides it into two parallel paths: one path goes towards the central element, which is an unbalanced coupler that measures a portion of the optical signal power, while the other path goes directly towards the output connector. For this purpose, optical circulators are used to separate the upstream signal from the downstream signal, directing the former to an unbalanced coupler responsible for diverting a small fraction of its optical power for measurement without interrupting the main transmission.Finally, a power meter is responsible for evaluating the intensity of the optical monitoring signal and thus informing the technician whether the fiber is being used to serve a customer or not.

[032] The apparatus proposed in this invention can be inserted into the passive optical network between the OLT and the splitter for analysis on the primary side of the network, as described in Figure 2, or it can be inserted between the splitter and each ONT / ONU for analysis on the secondary side. Petition 870240110269, dated 12 / 26 / 2024, page 17 / 51 13 / 14 of the network, a situation described in Figure 3. Associated with each of these possible scenarios, the present invention proposes a method for using the measuring device.

[033] Specifically, Figure 5 presents a flowchart describing the process of verifying and identifying active or available ports on an optical splitter by analyzing the primary side of the PON network. To do this, initially, the equipment is connected to the primary side of the splitter, where the reference power is measured. Then, each port on the secondary side is disconnected sequentially, and it is checked whether the reference power has changed: if there is a change, the port is identified as active; otherwise, it is considered available. The active port is reconnected for confirmation, and the process is repeated for other ports, if any. The procedure is completed when all ports have been verified.

[034] Finally, Figure 6 presents a flowchart describing the process of identifying active or inactive ports in a PON from the secondary side of the splitter. The procedure begins with the selection of the port to be tested, followed by the connection of the proposed measuring equipment. After waiting a few seconds for signal stabilization, the optical power detection is checked: if power is detected, the port is considered active; otherwise, it is marked as inactive. Then, the active port is reconnected to confirm the reading. The process is repeated for other ports, if any, until all are tested, ending the procedure. ADVANTAGES

[035] The proposed method and apparatus for identifying active and available ports in an optical splitter for signal distribution in passive optical networks offer several important advantages. First, there is the versatility to be used on both the primary and secondary sides of the splitter, expanding its application possibilities in different PON network scenarios. Additionally, the proposed invention provides greater operational efficiency by allowing a quick and low-complexity verification of the ports, significantly reducing the time required for identification compared to manual methods or those based on packet reading in communication protocols. In this way Petition 870240110269, dated 12 / 26 / 2024, page 18 / 51 In addition to the 14 / 14 system, it also facilitates the updating of network records by storing the information collected during the process. This advantage is especially useful for network maintenance and planning, ensuring that information is always up-to-date and accurate. Finally, the equipment is easy and inexpensive to use, having been designed to be intuitive, allowing technicians with varying levels of experience to use the method effectively, reducing the need for extensive training and enabling greater efficiency in field operations. Petition 870240110269, dated 12 / 26 / 2024, page 19 / 51

Claims

1 / 2 CLAIMS 1 - Apparatus for identifying terminal modules in passive optical networks for detecting the occupied state, characterized by using an optical assembly based on circulators, for separating and combining the bidirectional components of the optical signal, an unbalanced coupler, for separating a small fraction of the optical power insufficient to interrupt the upstream communication flow, and an optical power meter, for measuring the optical power level in each test scenario foreseen in the proposed method. 2 - Method for identifying terminal modules in passive optical networks for detecting the occupied state, characterized by allowing the identification of terminal equipment (ONTs / ONUs) connected to a passive optical network (PON) through the measurement of the optical power of the upstream signal under different test conditions and, consequently, enabling the determination of the presence of an active terminal equipment and detection of the occupied state of that fiber. 3 - Method for identifying terminal modules in passive optical networks for detecting the occupied state, according to claim 2, characterized by allowing the verification of the occupied state of a given passive optical network through tests on the primary side of the optical power splitter, employing a procedure based solely on measuring optical power levels using the proposed apparatus connected between the OLT and the splitter; for this purpose, an initial measurement of a reference power is performed, which is compared with new measurements performed after the sequential disconnection of each fiber present on the secondary side of the optical power splitter. 4 - Method for identifying terminal modules in passive optical networks for detecting the occupied state, according to claim 2, characterized by allowing the verification of the occupied state of a given passive optical network through tests on the secondary side of the optical power splitter, employing a procedure based solely on measuring optical power levels using the proposed apparatus connected to each port between the splitter and each ONT / ONU, for this purpose, Petition 870240110269, dated 12 / 26 / 2024, p. 20 / 51 2 / 2 the presence of optical power is measured at each port connected to the secondary side of the splitter using the proposed apparatus, a procedure that must be repeated with the positioning. Petition 870240110269, dated 12 / 26 / 2024, p. 21 / 51

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