Portable device for checking coverage of optical fiber link

Abstract

Disclosed is an apparatus for checking the coverage of an optical fiber link of an optical fiber network, the link connecting a device at a central office of a telecommunications service provider and terminal equipment within the network. The device comprises a processing unit, a positioning unit, a modem unit and a connection enabler. The modem unit is configured to connect to the optical fiber link at the terminal equipment and retrieve data indicating that the optical fiber link is established. The positioning unit is configured to provide geographic coordinates of the device. The processing unit is configured to provide encrypted data by encrypting data indicating that the optical fiber link is established and geographic coordinates. The connection enabler is configured to transmit encrypted data to a further device located in the vicinity of the device.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber networks. In particular, the present invention relates to the field of checking the coverage of optical fiber links in optical fiber networks, especially in FTTH (Fiber-To-The-Home) networks. Background Art

[0002] As is known, in a FTTH (Fiber to the Home) network, an optical fiber link is provided between a telecommunications service provider's (referred to as service provider) central office (wherein the Optical Line Terminal (OLT) equipment is housed) and a customer's premises (where the Optical Network Terminal (ONT) equipment is located).

[0003] In a point-to-point topology, the connection between the OLT and the ONTs comprises a dedicated optical fiber link. In a point-to-multipoint topology, a PON (Passive Optical Network), in particular a GPON (Gigabit-capable Passive Optical Network), is typically used to deliver optical signals from the OLT to multiple ONTs by deploying optical fibers with optical splitters in a tree-like architecture, which is often referred to as an optical distribution network (ODN). The OLT typically comprises a plurality of ports, and each of these ports, when active, implements an operating optical tree at the end of which a plurality of users are connected.

[0004] When deploying an FTTH network, an optical terminal box (OTB) is typically installed at the location where the distribution network is terminated (eg, in a building where the customer's premises are located). The OTB provides connectivity to the customer, whose equipment is typically connected to the OTB via a drop cable.

[0005] At the end of the OTB deployment process, it is necessary to check the coverage of the fiber link between the OLT and the OTB (i.e., test whether the fiber link reaches the OTB in question correctly from the OLT) to verify that the installation is working correctly. The prior art provides for testing the fiber link by an optical time domain reflectometer (OTDR) equipment installed in the central office of the service provider. Alternatively, an operator with a portable OTDR equipment can perform the test at the OTB location.

[0006] Examples of prior art techniques and devices are briefly identified below.

[0007] US8,588,571B1 discloses a technology for installing an optical fiber network, which includes preparing physical points to install a feeder cable and a plurality of access stub lines along a plurality of customer premises, which can potentially be connected to the feeder cable to obtain communication services. Each access stub line extends from the feeder cable toward the customer premises, and each access stub line ends at a different initial terminal point. There is a one-to-one correspondence between the user premises and the access stub lines extending from the feeder cable. A demarcation device is attached to the end of each access stub line at each initial terminal point. The demarcation device includes an optical reflector that reflects an optical test signal for testing the integrity of the associated access stub lines in the feeder cable and the access stub line.

[0008] WO 2014 / 070511 A1 discloses a splitter assembly, which includes a splitter housing, a passive optical power splitter positioned in the splitter housing, and a plurality of splitter output leads extending outwardly from the splitter housing. Each splitter output lead includes an optical fiber structure having a first end optically coupled to the passive optical power splitter and a second end mounted with an optical fiber connector. Each splitter output lead has different test characteristics, so that the splitter output leads can be individually identified during optical network testing.

[0009] US2013 / 022350 A1 discloses an OFN radio frequency identification (RFID) method for deploying and / or providing services and / or locating faults in an optical fiber network (OFN). The method includes: providing at least one RFID tag on at least one OFN component among a plurality of OFN components constituting the OFN, and writing OFN component data to the at least one RFID tag, the data relating to at least one attribute of the OFN component associated with the RFID tag. Using one or more mobile RFID readers to write RFID tag data to and read RFID tag data from the RFID tag. The OFN component data is recorded and stored in an OFN database unit. A plurality of OFN components are deployed, and the OFN component data is used to provide operation of the OFN. The method may also include locating faults in the OFN using the OFN component data and a plurality of locations on a spatial map. Summary of the invention

[0010] The inventors have noticed that checking the coverage of the fiber link between the OLT and the OTB by testing the fiber link at the OLT is cumbersome (also from the point of view of the costs involved in the test equipment) and may be unreliable. In fact, FTTH networks are passive networks and the identification of the OTB is usually done by an operator who has to determine the reflected signal on a layout image of the reflection measurement. This technique may provide a false association between the estimated location of the OTB determined by the operator based on the data provided by the test equipment and the actual address of the building where the OTB is located.

[0011] The option of an operator sending it on-site at the building where the OTB is located using portable OTDR equipment is also cumbersome, being expensive and requiring specialized skills.

[0012] In view of this, the Applicant has solved the problem of providing a device for checking the coverage of an optical fiber link that overcomes the above-mentioned disadvantages. In particular, the Applicant has solved the problem of providing a device and a system for checking the coverage of an optical fiber link, which allows testing the optical fiber link in a simpler and more reliable way relative to the prior art. As will be apparent from the following description, the invention also allows testing the optical fiber link in a safe way.

[0013] In the following description and claims, the expression “checking the coverage of a fiber optic link”, wherein the fiber optic link is deployed within a fiber optic network between equipment located at a central office of a telecommunication service provider (e.g., OLT) and terminal equipment (e.g., OTB or ONT) located at an expected location within the fiber optic network, means:

[0014] - checking whether a fibre link is established between the central office equipment and the terminal equipment under consideration (this includes checking whether the identifier of the means for checking the coverage of the fibre link at the terminal equipment under consideration is actually included in the list of identifiers of equipment connected to the active ports of the equipment and / or checking whether a specific coverage check code set at the terminal equipment under consideration corresponds to a corresponding code available at the central office equipment); and

[0015] - Checking the position of the terminal equipment of the optical fiber link, which means making sure that the actual position of the terminal equipment of the optical fiber link is its expected position.

[0016] Furthermore, in the following description and claims, two devices are referred to as being "near each other" when a distance between the two devices is less than one meter, preferably less than a few centimeters (eg, one centimeter).

[0017] According to a first aspect, the present invention provides an apparatus for checking the coverage of an optical fiber link of an optical fiber network, the optical fiber link connecting equipment at a central office of a telecommunications service provider and terminal equipment within the optical fiber network, the apparatus comprising:

[0018] - Processing unit;

[0019] - positioning unit;

[0020] - a modem unit; and

[0021] - connection enabler,

[0022] The modem unit is configured to connect to the optical fiber link at the terminal equipment and retrieve data indicating that the optical fiber link is established,

[0023] The positioning unit is configured to provide geographical coordinates of the device.

[0024] Preferably, the processing unit is configured to provide encrypted data by encrypting the data indicating that the optical fiber link is established and the geographical coordinates.

[0025] Preferably, the connection enabler comprises a short-range transceiver, such as an RFID tag.Alternatively, the connection enabler may comprise a cable connector or a cable interface instead of or in addition to a short-range transceiver.

[0026] Preferably, the connection enabler is configured to transmit the encrypted data to another device located in the vicinity of the device. Preferably, the connection enabler is further configured to transmit an identifier of the modem unit to the further device.

[0027] Preferably, the short-range transceiver comprises an antenna configured to transmit encrypted data to a further device located in the vicinity of the device.

[0028] Preferably, the positioning unit is a satellite positioning unit, more preferably a global navigation satellite system unit.

[0029] Preferably, the processing unit is configured to encrypt the data indicating that the optical fiber link is established and the geographical coordinates by using 64-bit encryption technology.

[0030] Preferably, the processing unit is configured to retrieve information indicating a date and time of day when said geographical coordinates are provided and to encrypt said information indicating a date and time of day together with said data indicating that said optical fibre link is established and said geographical coordinates.

[0031] Preferably, the device further comprises a rechargeable battery for supplying power to the processing unit, the positioning unit, the modem unit and the connection enabler.

[0032] Preferably, the apparatus further comprises a LAN interface connected to the modem unit and the processing unit, the LAN interface being configured to make available to the processing unit electrical signals generated by conversion of optical signals received by the modem unit from the optical fibre link.

[0033] Preferably, the device further comprises a visual signalling unit configured to show the data and / or the geographical coordinates indicating that the optical fibre link is established to an operator operating the device.

[0034] According to an embodiment of the invention, the processing unit is configured to provide a machine-readable optical label containing the encrypted data. The visual signaling unit is configured to display the machine-readable optical label to be read by the further device. Preferably, the machine-readable optical label further contains an identifier of the modem unit.

[0035] Preferably, the device is portable.

[0036] According to an embodiment of the invention, the processing unit is configured to start a timer when the geographical coordinates are provided by the positioning unit, the timer having a predetermined duration between one minute and ten minutes.

[0037] Preferably, the modem unit is further configured to retrieve a received power indicating the power of optical signals received by the modem unit from the optical fiber link, and a transmitted power indicating the power of optical signals transmitted by the modem unit through the optical fiber link.

[0038] Preferably, the device further comprises a container, wherein the processing unit, the positioning unit, the modem unit and the connection enabler are non-releasably encapsulated in the container.

[0039] According to a second aspect, the present invention provides a system comprising a first device as described above and a second device configured to connect to the first device and receive the encrypted data from the first device. According to an embodiment of the present invention, the second device is configured to receive the encrypted data from a connection enabler of the first device. Alternatively or additionally, the second device is configured to receive the encrypted data by reading a machine-readable optical label containing the encrypted data, the machine-readable optical label being displayed on a visual signaling unit of the first device.

[0040] Preferably, the first device is further configured to receive an identifier of the modem unit from the first device.

[0041] Preferably, the second device comprises a coverage check application software configured to decrypt the encrypted data, retrieve the geographic coordinates and compare the geographic coordinates with the expected geographic coordinates of the terminal equipment stored in a network inventory managed by the service provider. According to an embodiment of the present invention, the coverage check application is configured to use an identifier of the modem unit to retrieve an encryption key uniquely associated with the first device to decrypt the encrypted data.

[0042] Preferably, the coverage check application is further configured to check whether the identifier of the modem unit of the first apparatus is included in a list of identifiers of equipment connected to the active port of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention will become more apparent from the following detailed description read with reference to the accompanying drawings, given by way of example and not limitation, in which:

[0044] - Figure 1 schematically illustrates a fiber optic network comprising fiber optic links;

[0045] - Figure 2 is a block diagram of an apparatus for checking the coverage of an optical fiber link according to the present invention;

[0046] - Figure 3 is a flow chart illustrating the operation of the apparatus according to the present invention; and

[0047] - Figure 4 is a flow chart illustrating the steps of a method for checking the coverage of a fiber optic link using the apparatus of the present invention. DETAILED DESCRIPTION

[0048] Figure 1 Schematically illustrated is an optical fiber network, in particular an exemplary FTTH network, which is to be regarded as a non-limiting example of an optical fiber network to which the present invention may be applied. More particularly, Figure 1 The exemplary fiber optic network schematically shown in FIG. 1 is a passive optical network.

[0049] Figure 1 The exemplary optical fiber network 1 shown is a point-to-multipoint optical fiber network. This is not restrictive, as the invention can also be similarly applied to other types of networks, such as point-to-point networks. Figure 1 The fiber optic network of FIG. 1 comprises an optical line terminal (OLT) 11 located at a central office 12 of a service provider. As is known, the OLT is connected to a core network of the service provider (not shown in the figure) on one side and to a plurality of ports (one of which is at Figure 113 ) is connected to the distribution network. From each port, an optical fiber cable of the distribution network connects the OLT to a corresponding optical splitter 13, from which a plurality of further optical fiber cables of the distribution network leave, each of which reaches one or more user nodes 14 installed at the user's premises, which are generally referred to as optical network units (ONUs) or optical network terminals (ONTs). When a port of the OLT is configured to be connected to one or more ONTs via a corresponding optical fiber link, the port of the OLT is indicated as "active". Figure 1 There is schematically shown one single ONT 14 at a customer's premises located in a building 15. An end-to-end link comprising a plurality of spans of optical fibre cables connects the OLT 11 and the ONTs at the customer's premises. Figure 1 The exemplary fiber optic network 1 of also includes an optical terminal box (OTB) 16 located outside or inside (eg, on a wall or underground) a building 15. A drop cable is typically used to reach the user's premises from the OTB 16.

[0050] As is known, telecommunications service providers that provide services over a fiber optic network typically maintain a server, hereinafter referred to as a "library server," that includes a network database or network library containing data identifying network elements that have been deployed within the fiber optic network (i.e., in the above-mentioned passive optical network, OLTs, optical splitters, OTBs, etc.). For each network element, the data may include an identifier associated with the network element (e.g., a serial number) and the geographic coordinates (latitude and longitude) of the location of the network element.

[0051] The following description will be related to checking the coverage of a fiber link (which will be indicated as fiber link 17) starting from OLT 11 and terminating at OTB 16. This is not limiting in any way, as the apparatus to be described below can be used to check the coverage of any fiber link connecting the OLT and terminal equipment of the fiber link located within a fiber network (such as, in a passive optical network, a fiber link connecting the OLT and OTB, the OLT and ONT, the OLT and an optical splitter, etc.).

[0052] The present invention relates to a device and a system for checking the coverage of an optical fiber link. The device of the present invention is configured to be manipulated by an operator to check the coverage of an optical fiber link of a considered optical fiber network. Therefore, the device is a portable device. The device will also be indicated as a "verification device".

[0053] Figure 2 Shown is a block diagram illustrating the building blocks of a portable device 2 (or simply, a verification device) for checking the coverage of an optical fiber link according to an embodiment of the present invention.

[0054] Figure 2The verification device 2 schematically shown in FIG. 1 preferably comprises:

[0055] - processing unit 21;

[0056] - a battery 22;

[0057] - positioning unit 23;

[0058] - connection enabler 24;

[0059] - Modem unit 25;

[0060] - Local Area Network (LAN) interface 26; and

[0061] - Optionally, a visual signalling unit 27, such as a display.

[0062] The components indicated above are arranged in a container and preferably enclosed therein in a non-releasable manner. For example, the components are tamper-proof sealed in the container by embedding them in the container, for example using a resin, to avoid any falsification of the verification device 2.

[0063] The battery 22 is connected to the other components of the verification device 2. These connections are Figure 2 The processing unit 21 is connected to a satellite positioning unit 23, a connection enabler 24, a LAN interface 26 and an optional display 27. The LAN interface 26 is connected to a modem unit 25.

[0064] The processing unit 21 may be a microcontroller and is configured to control the operation of the verification device 2. For example, the processing unit 21 may be a commercially available microchip, such as an Atmel ATmega328P microcontroller manufactured by Atmel Corporation.

[0065] The positioning unit 23 is configured to provide the geographical coordinates (latitude and longitude) of the location of the verification device. The positioning unit 23 is preferably a satellite positioning unit, more preferably a GNSS (Global Navigation Satellite System) unit. More preferably, the satellite positioning unit 23 is a GPS (Global Positioning System) receiver. Alternatively, the positioning unit 23 can be a mobile network-based or mobile network-assisted positioning unit that complies with, for example, 3GPP standard TS36.305 or TS38.305.

[0066] The connection enabler preferably has a short-range connectivity function, because the connection enabler is configured to connect to a transmission unit 3 located in its vicinity, which is preferably an independent device external to the verification device 2. According to an embodiment of the present invention, the verification device 2 and the transmission unit 3 are configured to exchange data via the connection enabler 24.

[0067] In particular, according to this embodiment of the invention, the connection enabler 24 comprises a short-range transceiver. Optionally, instead of or in addition to the short-range transceiver, the connection enabler 24 may comprise a connector or interface for a cable to allow a short-range cable connection (e.g., 1 to 5 m long) to an adjacent transmission unit 3.

[0068] In addition, the connection enabler 24 preferably includes non-volatile memory that is configured to store data, as will be described below, including an identifier (e.g., a serial number) associated with the modem unit 25 of the verification device 2 and other data provided by the verification device 2 and related to link connectivity.

[0069] According to an embodiment of the present invention, the short-range transceiver included in the connection enabler 24 is a radio transceiver with a range of radio coverage from several centimeters (e.g., one centimeter) to one meter (e.g., the radio coverage range can be about ten centimeters). The short-range transceiver includes an antenna for transmitting the data stored in the memory to the transmission unit 3. The short-range radio transceiver is preferably an RFID transceiver or an RFID tag. More preferably, the short-range transceiver is a passive RFID tag, and the above-mentioned memory is a memory of the RFID tag. Alternatively, the short-range transceiver can be, for example, a Bluetooth transceiver, a ZigBee transceiver or a Wi-Fi transceiver. It should be noted that the use of an RFID tag increases security because the operator needs to bring the transmission unit 3 close to the verification device 2 (e.g., within a few centimeters) to read the data stored in the memory. This advantageously prevents the data from being maliciously read by other devices in the vicinity of the verification device 2.

[0070] The transmission unit 3 is preferably a device configured to provide a wireless connection (such as a 3G+, 4G or 5G connection) to, for example, the Internet via a mobile communication network managed by any service provider. The transmission unit 3 may be a smartphone with a SIM card, such as Figure 1Schematically represented in . The transmission unit 3 may include an RFID reader and / or a Bluetooth transceiver and / or a ZigBee transceiver and / or a Wi-Fi transceiver. The transmission unit 3 can advantageously be configured to read a machine-readable optical label or a barcode (such as a QR code). The transmission device 3 is provided with a client component of an application software (hereinafter referred to as an application or app for short), as will be described in detail below, the application software is configured to specifically process data provided to the transmission unit 3 by the verification device 2 via the connection enabler 24. The application is preferably a web application that utilizes the processing power residing on an application server managed by a service provider. In particular, as will be described below, the application server can be connected to a library server of the service provider for exchanging data with the library server to process data provided to the transmission unit 3 by the verification device 2 via the connection enabler 24. The application is indicated as a "coverage check application" and the application server is the "coverage check server" already mentioned above.

[0071] The modem unit 25 comprises a modem configured to connect to a fiber optic network. The modem unit 25 is preferably associated with an identifier (e.g., a serial number). The modem may be a commercially available modem. In particular, the modem unit 25 may be in the form of a GPON ONT SFP (Small Form Factor Pluggable) module. The operation of the modem is known and will not be described in further detail. Figure 1 In the exemplary optical fiber network of FIG. 1 , the modem unit 25 is an ONT provided with an optical fiber connector (not shown in the figure) for connecting an optical fiber cable. Figure 1 In the exemplary optical fiber network of , the modem unit 25 is configured to be connected to the OTB 16 via an optical fiber cable having a length of several meters (eg, five meters), and is configured to receive an optical signal transmitted through the tested optical fiber link 17 from the OTB 16.

[0072] The LAN interface 26 includes a port (e.g., an Ethernet port) through which the LAN interface 26 is connected to the modem unit 25. The LAN interface 26 connects the modem unit 25 to the processing unit 21. In particular, the LAN interface 26 makes the electrical signal generated by the conversion of the optical signal received by the modem unit 25 available to the processing unit 21.

[0073] The battery 22 is provided with a connector (not shown in the figure) for connecting a power cable. The battery 22 is preferably a rechargeable battery. The battery 22 may be a 12V 6AH rechargeable lithium battery.

[0074] The optional visual signal notification unit 27 may be, for example, an LCD (Liquid Crystal Display). The visual signal notification unit 27 is configured to provide visual indications to an operator manipulating the verification device 2. Furthermore, as will be described in more detail below, the visual signal notification unit 27 is configured to display a machine-readable optical label or barcode (e.g., a QR code) provided by the processing unit 21 that may contain data to be read by the transmission unit 3. Alternatively or additionally, the verification device 2 may include an audio signal notification unit (such as a buzzer or a beeper) to provide an audio indication to the operator, such audio indication replacing or integrating the visual indication provided by the visual signal notification unit 27.

[0075] According to the present invention, the coverage check operation of the optical fiber link 17 includes connecting the verification device 2 to the OTB 16, and:

[0076] (i) checking that an optical fiber link 17 is established between the OLT 11 and the modem unit 25 of the verification device 2 connected to the OTB 16;

[0077] (ii) checking that the location of the OTB 16 corresponds to the expected location stored in the network repository; and

[0078] (iii) Checking that the identifier (eg, serial number) of the modem unit 25 of the verification device 2 is included in the list of identifiers of the ONTs actually connected to the active ports of the OLT 11 .

[0079] According to a variant, as an alternative to or in addition to the checking operation at point (iii) above, the operation of coverage checking of the optical fiber link 17 at the OTB 16 includes checking that the configuration information associated with the modem unit 25 when the verification device 2 is operated to check the coverage at the OTB 16 corresponds to the configuration information associated with the modem unit 25 stored at the OLT 11 when the link is established between the OTL 11 and the modem unit 25, as will be described in more detail below. The configuration information may be the content of a "password" field configured in the modem unit 25 by the processing unit 21 via the LAN interface 26. Advantageously, the processing unit 21 may set a different value of this configuration information in the modem unit 25 each time the verification device 2 is used to check the coverage of the corresponding optical fiber link. The configuration information will be indicated as "coverage check code" hereinafter. Therefore, the coverage check code is uniquely associated with the modem unit 25 and the coverage check operation at a specific OTB 16, and when the coverage check at the location of the OTB 16 is performed, the coverage check code can be used to safely check that the OLT 11 is connected to the verification device 2. In fact, the use of the serial number of the modem unit 25 at point (iii) above may have potential disadvantages. In fact, the serial number of the modem unit 25 can be cloned to another ONT that may be located far away from the location of the OTB 16, and the serial number may be used to provide an erroneous coverage check. Using the coverage check code as defined above advantageously allows overcoming this potential disadvantage.

[0080] The following will refer to Figure 3 and Figure 4 The flowchart shown is used to describe Figure 2 The verification device 2 schematically represented in FIG. 1 checks the operation of the coverage of the optical fiber link 17 .

[0081] Assume that an operator manning the verification device 2 arrives at the location of the OTB 16 to check the coverage of the optical fiber link 17 terminating therein.

[0082] When the verification device 2 is turned on at the OTB location, the processing unit 21 preferably operates the positioning unit 23 to provide the geographical coordinates of the verification device 2 (step 301), i.e. the latitude and longitude. These geographical coordinates substantially correspond to the geographical coordinates of the OTB 16. Once the geographical coordinates are determined, the processing unit 21 preferably operates the visual signal notification unit 27 (if present) to show the geographical coordinates to the operator. On the other hand, the processing unit 21 can start a timer with a predetermined duration, which can vary between one minute and ten minutes (for example, four minutes). The timer sets a time interval with the above-mentioned predetermined duration, as will be referred to below. Figure 4As described in the flowchart of , within this time interval, the operator should connect the verification device 2 to the OTB 16 and complete the process of checking the coverage of the optical fiber link 17. If the timer expires before the operator completes the process, the coverage check is considered invalid.

[0083] It will be appreciated by those skilled in the art that the use of a timer allows to increase the security of the coverage check, since it allows to avoid any mismatch between the actual location of the OTB 16 and the location where the operator is currently collecting the geo-coordinates. In practice, this will reduce the risk of fraudulent behavior by an operator who collects geo-coordinates at a location that does not correspond to the actual location of the OTB 16 and then moves away from that location to the actual location of the OTB 16 to physically connect the verification device 2 to the OTB 16 to perform the other operations necessary to complete the coverage check.

[0084] At step 302, preferably, the verification device 2 is connected to the OTB 16 via a fiber optic cable that is plugged into a fiber optic connector of the modem unit 25 of the verification device 2 at one end and into a corresponding connector included in the OTB 16 at the other end. At this point, the operator preferably waits until the modem unit 25 is aligned with the port of the active OLT 11 at the central office node 12. In other words, the operator waits for a connection to be established between one of the available ports at the OLT 11 and the modem unit 25 of the test device 2. The alignment process of the modem is known and will not be described in further detail below. Once aligned, the modem unit 25 starts receiving optical signals from the optical fiber link 17 and then starts transmitting optical signals through the optical fiber link 17. The modem unit 25 preferably converts the received optical signal into an electrical signal, which is transmitted to the processing unit 21 via the LAN interface 26.

[0085] The processing unit 21 then preferably processes the received electrical signal and retrieves the following data (which will be referred to as link connectivity data):

[0086] - Link status information indicating that the optical fiber link 17 is established;

[0087] - information indicating the actual alignment port of the OLT 11 (ie the active port of the OLT to which the modem unit 25 is connected) (ie the port identifier);

[0088] - Received power (or RX power) indicating the power of the optical signal received by the modem unit 25 from the optical fiber link 17. In current commercial modems, this information is usually indicated as "RX level"; and

[0089] - The transmit power (or TX power) indicating the power with which the modem unit 25 transmits the optical signal over the optical fiber link 17. In current commercial modems, this information is usually indicated as TX level.

[0090] Once the optical fibre link 17 is established and the link connectivity data is retrieved, the processing unit 21 preferably operates the visual signalling unit 27 (if present) to show the link connectivity data to the operator.

[0091] For example, when the optical fiber link 17 is established between the OLT 11 and the OTB 16, the link status information indicates the presence of an optical signal on the optical fiber link 17. In this case, the visual signal notification unit 27 may show the link status information represented by a message such as "Link Status OK". In addition, the received power and transmitted power information may be processed (automatically by the device or by an operator) to check whether the RX power is too low, and thus detect a possible failure or degradation in the optical fiber link 17. In addition, the operator may also process the port identifier of the OLT active port retrieved by the verification device 2, and detect a possible OLT port reversal, which, as is known, may cause problems.

[0092] The processing unit 21 also recovers the identifier of the modem unit 25 .

[0093] According to the advantageous variant already mentioned above, when the verification device 2 is turned on at the OTB location, the processing unit 21 also generates a pseudo-random number (e.g., a 10-digit number) and configures the modem unit 25 via the LAN interface 26 with a coverage check code comprising the generated pseudo-random number. In particular, for example, the processing unit 21 can use the coverage check code to set the content of the "password" field of the modem unit 25. As described below, when the optical fiber link 17 is established between the OLT 11 and the OTB 16, the OLT 11 preferably reads the coverage check code from the modem unit 25 and stores it for future checks.

[0094] At step 303, the processing unit 21 preferably associates the link connectivity data and the coverage check code according to the above-mentioned variant with the geographical coordinates detected by the positioning unit 23 and with information indicating the date and time of day when the link connectivity data was determined, and the date and time of day correspond to the date and time of day when the coverage check of the optical fiber link 17 was performed. The data set including the link connectivity data, the geographical coordinates and the information indicating the date and time of day is called "verification data". According to the above-mentioned variant, the verification data also includes the coverage check code. At step 303, the processing unit 21 preferably encrypts the verification data. For example, encryption according to the known DES (Data Encryption Standard) protocol, such as 64-bit encryption technology, can be used.

[0095] Preferably, the processing unit 21 uses an encryption key that is uniquely associated with the verification device 2. In this way, different verification devices are preferably provided with different encryption keys. Then, if one encryption key becomes public inadvertently, malicious use of the key can be easily avoided by not using a single verification device associated with the key that became public. According to an embodiment of the present invention, the encryption keys of the verification devices are stored in a key table provided and maintained by the service provider in the coverage check server. The respective encryption keys are preferably stored in the key table as being uniquely associated with the identifier of the modem unit of the corresponding verification device.

[0096] At step 304, the processing unit 21 preferably transmits the encrypted authentication data and the identifier of the modem unit 25 to the connection enabler 24, wherein the encrypted authentication data and the identifier of the modem unit 25 are stored in a memory.

[0097] Alternatively or additionally, at step 304, processing unit 21 provides a machine-readable optical label or barcode (e.g., QR code) including the encrypted authentication data and an identifier of modem unit 25. The machine-readable optical label may then be displayed by visual signaling unit 27 to be read by transmission unit 3.

[0098] Figure 4 is a flow chart illustrating actions that may be performed (e.g., by an operator) when checking the coverage of an optical fiber link 17 using the above-described verification device 2 in combination with a transmission unit 3. For simplicity, it is assumed that, according to a preferred embodiment of the present invention, the positioning unit 23 is a GPS receiver and that the connection enabler 24 of the verification device 2 comprises a short-range transceiver (in particular an RFID tag). Furthermore, it is assumed that the OTB 16 comprises another RFID tag comprising an identifier (e.g., a serial number) associated with the OTB 16. Alternatively or additionally, the identifier associated with the OTB 16 may be contained in a barcode (e.g., a QR code) attached to the OTB 16. Finally, it is assumed that the transmission unit 3 is a smartphone.

[0099] When the operator reaches the position of OTB 16, he operates the verification device 2 to perform the above reference Figure 3 The flowchart has shown the steps of the method, which will consist of Figure 4 Step 401 in the flowchart is represented.

[0100] In particular, when the verification device 2 is turned on at the location of the OTB 16, the verification device 2 preferably retrieves the geographical coordinates by means of its GPS receiver 23. Then, the operator connects the OTB 16 and the verification device 2 by means of an optical fiber cable, which is plugged into the optical fiber connector of the modem unit 25 of the verification device 2 at one end and into the corresponding connector included in the OTB 16 at the other end. The operator waits for a connection to be established between one of the available ports at the OLT 11 and the modem unit 25 of the verification device 2. If the modem unit 25 fails to align with the active port of the OLT 11, the coverage check of the optical fiber link 17 fails, and the verification device 2 may return a warning message to the operator, for example, by means of a visual signaling unit 27. When the connection is established, the verification device 2 retrieves the link connectivity data. Furthermore, according to the above variant, the processing unit 21 configures the modem unit 25 with the coverage check code that has been generated for this particular coverage check operation. When the connection is established, the coverage check code is then read by the OLT 11.

[0101] The verification device 2 then preferably encrypts the verification data including the link connectivity data, the geographical coordinates and the date and time of day information. According to the above variant, the verification data also includes a coverage check code. The processing unit 21 preferably stores the encrypted verification data and the identifier of the modem unit 25 in the RFID tag 24. Alternatively or additionally, the encrypted verification data and the identifier of the modem unit 25 are processed by the processing unit 21 to provide a machine-readable optical label, such as a QR code containing the encrypted verification data and the identifier of the modem unit 25, which can be displayed on the visual signal notification unit 27 of the verification device 2.

[0102] At this time, the operator can run the coverage check application installed on the smart phone 3 to implement the following coverage check operation. When the coverage check application is running on the smart phone 3, the smart phone 3 is preferably operated to connect to the application server and use the processing power of the application server to perform the operations described below.

[0103] At step 402, the operator uses the RFID transceiver of the smart phone 3 to read the encrypted verification data and the identifier of the modem unit 25 stored in the memory of the RFID tag 24 of the verification device 2. Alternatively, according to the above variation, the operator can operate the smart phone 3 to read a machine-readable optical label containing the encrypted verification data and the identifier of the modem unit 25, which can be displayed on the visual signal notification unit 27 of the verification device 2. The coverage check application then preferably operates the smart phone 3 to send the encrypted verification data and the identifier of the modem unit 25 to the application server. Once the data is decrypted, the data is used for the inspection described below in this document, and the data is stored by the service provider to track the coverage inspection of the optical fiber link under consideration.

[0104] At step 403, the operator uses the RFID transceiver of the smart phone 3 to read the identifier associated with the OTB 16 stored in the RFID tag associated with the OTB 16. Alternatively, the operator may use the smart phone 3 to read a machine-readable optical tag containing the identifier associated with the OTB 16 and attached to the OTB 16.

[0105] At step 404, the coverage check application preferably decrypts the encrypted verification data. Preferably, the decryption is performed at the coverage check server by reading a key table including encryption keys using the identifier of the modem unit 25 and retrieving the encryption key uniquely associated with the verification device 2. The coverage check server then decrypts the encrypted verification data using the encryption key.

[0106] Then, preferably, the coverage check application checks the geographical coordinates that have been measured by the GPS receiver 23 of the verification device 2. In particular, the coverage check application operates the smartphone 3 to send the identifier of the OTB 16 to the application server, which uses the identifier of the OTB 16 to query the network library of the library server and retrieve the GPS coordinates of the OTB 16 stored in the network library and associated with the identifier of the OTB 16. These GPS coordinates are actually the GPS coordinates of the expected position of the OTB 16. The coverage check application then compares the GPS coordinates measured by the verification device 2 with the GPS coordinates of the OTB 16 stored in the network library of the library server. In particular, the position corresponding to the GPS coordinates measured by the verification device 2 is compared with the position corresponding to the GPS coordinates of the OTB 16 stored in the network library. If the distance between the measured position and the stored position is less than a predetermined tolerance distance of, for example, 30m, the coverage check application preferably determines that the measured position matches the stored (expected) position.

[0107] If the distance between the measured location and the stored location is above a predetermined tolerance distance, the coverage check application preferably operates the smartphone 3 to provide a warning message to the operator (a visual message to be shown on the display of the smartphone 3 or an audio message to be reproduced by the speaker of the smartphone 3) indicating that the coverage check of the optical fiber link 17 has failed. In this case, the GPS coordinates of the OTB 16 stored in the network repository may be overwritten with the GPS coordinates measured by the verification device 2 and sent to the application server.

[0108] At step 405, preferably, the coverage check application provides for the application server to query the OLT 11 at the central office of the service provider and request a list including identifiers (e.g., serial numbers) of the ONTs 14 that are actually connected to the active ports of the OLT 11. Once the list is retrieved from the OLT 11, preferably, the coverage check application checks whether the identifier associated with the modem unit 25 of the verification device 2 is included in the list collected from the OLT 11. If the identifier associated with the modem unit 25 of the verification device 2 is included in the list collected from the OLT 11, the coverage check application preferably determines that the modem unit 25 is actually connected to the active port of the OLT 11, and preferably provides a corresponding confirmation message to the operator on the display of the smart phone 3. Otherwise, if the identifier associated with the modem unit 25 of the verification device 2 is not included in the list collected from the OLT 11, the coverage check application provides a warning message indicating failure to the operator on the display of the smart phone 3.

[0109] According to the variant described above, in addition to or as an alternative to the above-described check of the identifier of the modem unit 25, the coverage check application provides for the application server to check whether the coverage check code included in the verification data corresponds to the coverage check code that has been read by the OLT 11 when the connection has been established. If the coverage check code included in the verification data provided by the verification device 2 corresponds to the coverage check code available at the OLT 11, the coverage check application preferably determines that the OLT 11 is actually connected to the modem unit 25 of the verification device 2 at the location of the OTB 16 (and not to a clone ONT, for example), and provides a corresponding confirmation message to the operator on the display of the smartphone 3. Otherwise, if the coverage check code included in the verification data does not correspond to the coverage check code available at the OLT, the coverage check application provides a warning message indicating failure to the operator on the display of the smartphone 3.

[0110] If all considered checks performed as described above return a positive result, the coverage check application may provide a final confirmation message to the operator on the display of the smartphone 3, indicating that the coverage check of the optical fibre link 17 was successful.

[0111] The above-mentioned device advantageously allows to check the coverage of the optical fiber link in an efficient and reliable manner. In fact, the device is a portable device that can be easily manipulated by an operator and brought to the location where the coverage of the optical fiber link is to be checked to verify that the link is established and works correctly. The verification device has a simple architecture and it can be operated in a simple manner. In addition, the verification device gives reliable and secure information. In particular, the verification device provides the geographical coordinates of the location where the coverage check is performed in a reliable and secure manner. The coordinates are reliable because they are provided by a satellite (or alternatively, network-based or network-assisted) positioning unit of the verification device connected in a way to avoid any falsification (for example, the processing unit sets a timer that avoids the operator from moving during the coverage check process and detecting the coordinates at different locations). In addition, according to a preferred embodiment of the present invention, the components of the verification device are sealed in a container and cannot be falsified. This means that the device provides an extremely reliable association between, for example, the measured location of the OTB and the actual address of the building where the OTB is located. This also ensures that data such as the identifier or geographical coordinates of the modem unit cannot be maliciously modified for coverage inspection. The described use of a specific coverage check code randomly generated at the verification device once the coverage check operation is started allows further improving the reliability of the operation. The security of the data is also enhanced by encrypting the data obtained by the verification device before forwarding it to the transmission unit used by the operator to run the coverage check application.

Claims

1. A device (2) for checking the coverage of an optical fiber link (17) of an optical fiber network (1), the optical fiber link (17) connecting equipment (11) at a central office (12) of a telecommunications service provider and terminal equipment (16) located within the optical fiber network (1), the device (2) comprising: - a processing unit (21); - a positioning unit (23); - a modem unit (25); as well as - connection enabler, The modem unit (25) is configured to connect to the optical fiber link (17) at the terminal equipment (16) and to retrieve data indicating that the optical fiber link (17) is established, The positioning unit (23) is configured to provide the geographical coordinates of the device (2); The processing unit (21) is configured to provide encrypted data by encrypting the data indicating that the optical fiber link (17) is established and the geographical coordinates, The connection enabler (24) is configured to transmit the encrypted data to a further device (3) located in the vicinity of the device (2).

2. The device (2) according to claim 1, wherein: The positioning unit (23) is a Global Navigation Satellite System unit.

3. The device (2) according to claim 1 or 2, wherein: The connection enabler (24) includes an RFID tag.

4. The device (2) according to any one of claims 1 to 3, wherein: The processing unit (21) is configured to encrypt the data indicating that the optical fiber link (17) is established and the geographical coordinates by using 64-bit encryption technology.

5. The device (2) according to any one of the preceding claims, wherein: The processing unit (21) is configured to retrieve information indicating a date and a time of day when the geographical coordinates are provided, and is configured to also encrypt the information indicating a date and a time of day together with the data indicating that the optical fiber link (17) is established and the geographical coordinates.

6. The device (2) according to any of the preceding claims, further comprising a rechargeable battery for supplying power to the processing unit (21), the satellite positioning unit (23), the modem unit (25) and the connection enabler (24).

7. The device (2) according to any of the preceding claims, further comprising a LAN interface (26), which is connected to the modem unit (25) and the processing unit (21), and the LAN interface (26) is configured to make the electrical signal generated by the conversion of the optical signal received by the modem unit (25) from the optical fiber link (17) available to the processing unit (21).

8. The device (2) according to any one of the preceding claims, wherein: The processing unit (21) is configured to provide a machine-readable optical label containing the encrypted data, and the device (2) also includes a visual signal notification unit (27), which is configured to display the machine-readable optical label to be read by the further device (3).

9. The device (2) according to any one of the preceding claims, wherein: The device (2) is portable.

10. The device (2) according to any one of the preceding claims, wherein: The processing unit (21) is configured to start a timer when the geographical coordinates are provided by the positioning unit (23), the timer having a predetermined duration between one minute and ten minutes.

11. The device (2) according to any one of the preceding claims, wherein: The modem unit (25) is further configured to retrieve a received power indicating the power of an optical signal received by the modem unit (25) from the optical fiber link (17), and a transmitted power indicating the power of an optical signal transmitted by the modem unit (25) through the optical fiber link (17).

12. The device (2) according to claim 1, wherein: The device (2) further comprises a container, in which the processing unit (21), the positioning unit (23), the modem unit (25) and the connection enabler (24) are non-releasably enclosed.

13. A system comprising a first device (2) and a second device (3) according to any one of the preceding claims, wherein: The second device (3) is configured to connect to the first device (2) and receive the encrypted data from the first device (2).

14. The system according to claim 13, wherein: The second device (3) comprises a coverage check application software configured to decrypt the encrypted data, retrieve the geographical coordinates, and compare the geographical coordinates with the expected geographical coordinates of the terminal equipment (16) stored in a network library managed by the service provider.

15. The system of claim 14, wherein: The coverage check application is further configured to check whether the identifier of the modem unit (25) of the first device (2) is included in the list of identifiers of equipment connected to the active port of the apparatus (11).

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