Methods for laying FTTH fiber optic cables

Abstract

The invention relates to the FTTH installation of fiber optic cables in a building (9) to create a fiber optic connection between a fiber optic termination unit (4) at a building entry point (BEP) and at least one fiber optic termination unit (2) designed as a fiber optic terminal adapter in the form of an optical network termination box (OTO), wherein the fiber optic connection is optionally routed via a further fiber optic termination unit (3, 3') designed as a hallway box (FB). The fiber optic cable length required between a fiber optic termination unit (2, 3, 3') to be arranged at an installation location and the fiber optic termination unit (3, 3', 4) nearest to the BEP (1) is determined as the installation distance.At the installation site, a fiber optic termination point (2, 3, 3') is provided, supplied with a coiled length (7) of fiber optic cable (5) exceeding the installation distance. The fiber optic cable (5) is equipped with at least one fiber optic connector (6) at each end. Fiber optic cable (5) of a length corresponding to the installation distance is unwound from the coil (7), and the at least one fiber optic connector (6) is connected to a fiber optic connector of the next fiber optic termination point (3, 3', 4). These steps are repeated as necessary until a fiber optic connection exists between the OTO and the BEP (1).

Description

[0001] The invention relates to a solution for FTTH installation of fiber optic cables within a building. It relates to a method for creating a fiber optic connection between a building entry point (hereinafter also referred to as BEP = Building Entry Point) and at least one optical network termination outlet (hereinafter also referred to as OTO = Optical Termination Outlet).

[0002] In recent years, the expansion of fiber optic networks has been greatly accelerated to provide broadband internet connections and other broadband data connections. At least in metropolitan areas, fiber optic cables have been increasingly laid and installed in public spaces, bringing fiber optic technology to so-called street cabinets or central offices in many locations. These optical line terminals (OLTs) provide telecommunications services to residential areas, city districts, or streets.Now that the penetration of the public communication infrastructure with fiber optic technology has progressed considerably, the so-called last mile, namely the section between the aforementioned Street Cabinet and the house connection or the subscriber connection of a respective user household or in the business premises of a user, is increasingly being given greater attention in order to be able to exploit the advantages of optical transmission technology even better.

[0003] From the perspective of network operators and companies providing telecommunications services, a distinction is made in this context between network level 3 and network level 4. Network level 3 refers to the area between the street cabinet or central office with the OLT (Optical Locator Terminal) and the building entry point (BEP), which is equipped with a passive termination device for an access network. In contrast, network level 4 encompasses the area between the aforementioned BEP and a terminal adapter at the customer's / user's premises, to which the customer can connect their own equipment used for accessing the wide area network, also known as customer premises equipment (PE). In the context of implementing the Fiber to the Home (FTTH) concept, this terminal adapter is a so-called Gf-TA (fiber optic terminal adapter).The focus of the invention described here is on the previously described network level 4 and on its fiber optic equipment.

[0004] However, the buildings in which fiber optic technology is to be installed vary considerably in size, layout, and other structural characteristics. In particular, the distances to be bridged by a single fiber optic connection also differ greatly. Therefore, it has become standard practice in the market to supply fiber optic cables by the meter for on-site installation of fiber optic technology in buildings. The additional components are then permanently connected to the fiber optic cable on-site, either directly or via special fiber optic connectors. Sections of the fiber optic cable supplied by the meter also need to be connected on-site.

[0005] Great care must be taken when creating splice connections and connecting the fiber optic cables to minimize attenuation (insertion loss) and reflections at the respective transition points. Accordingly, installation technicians must carry various specialized technical devices and tools to ensure a suitably efficient installation.

[0006] Such an approach is therefore very resource- and time-intensive. Furthermore, it should be noted that longer installation times, i.e., longer construction periods, as well as the requirement to install numerous additional components and equipment in hallways and stairwells of apartment buildings or multi-unit dwellings, negatively impact customer acceptance of FTTH deployment. On the other hand, the use of pre-terminated cables on both ends has hardly become established in the market due to the aforementioned individuality of different buildings, but is rather reserved for specific application and installation conditions.

[0007] The object of the invention is to avoid the aforementioned disadvantages. Therefore, a solution for FTTH deployment is to be provided that is flexible, resource-efficient, and time-saving with regard to the construction process, as well as contributing to better customer acceptance of the necessary measures. A corresponding method for this purpose will be described.

[0008] The problem is solved by a method with the features of claim 1. Advantageous embodiments and further developments of the invention are given by the dependent claims.

[0009] Before the proposed solution for this task is described in more detail below, some of the abbreviations already used in the description and in the patent claims and their meaning underlying this document will first be presented in the form of an overview.

[0010] This means: BEP = Building Entry Point CPE = Customer-owned communication equipment (CustomerPremises Equipment) FB = Hallway box (plural FBs) FTTH = Fiber to the home (fiber optic cable installation to the customer / user on site) Gf-TA = Fiber optic terminal adapter ≙ OTO = network termination box (Optical Termination Outlet at the customer / user - plural OTOs).

[0011] The proposed method for solving the aforementioned problem enables the creation of a fiber optic connection between a passive fiber optic termination device located at a BEP (Building Access Point) and an optical termination box (OTO) in a single installation. The fiber optic termination device at the BEP is a termination device for an access network to the public wide area network. The OTO is also a passive fiber optic termination device. Specifically, it is a fiber optic terminal adapter (FTA) designed as an optical termination box (OTO) that allows the connection of customer-owned equipment (CPE) for use with the wide area network. The corresponding fiber optic connection is established between the BEP and the OTO either directly or via at least one other passive fiber optic termination device, namely a floor box (FB).Corresponding passive fiber optic termination devices (OTO or FB) are disclosed, for example, in US 2015 / 0355428 A1 and in US 2017 / 0139169 A1.

[0012] According to the procedure presented below, the fiber optic connection between the BEP and the OTO is established according to the following steps: a) An installation distance is determined. This installation distance is the length of fiber optic cable required for laying the cable between a fiber optic termination point to be located at its designated installation location and the nearest fiber optic termination point in the direction of the building entry point (BEP). b) Arranging the fiber optic termination device intended for the installation location specified in a) at the installation location, wherein this fiber optic termination device is provided with a length of fiber optic cable exceeding the installation distance determined according to a) by a specified minimum amount. This cable consists of a fiber optic cable already fitted at both ends with at least one fiber optic connector (often with multiple fiber optic connectors), namely one fiber optic connector per fiber, which is at least partially wound (coiled) within the fiber optic termination device. One end of the fiber optic cable forming the cable length is connected to the fiber optic termination device by at least temporarily fixing the fiber optic connector located at that end of the fiber optic cable inside the fiber optic termination device.At least temporarily, the aforementioned fiber optic connector in the fiber optic handover device is fixed insofar as the position it occupies is either already a final position where it can be coupled with another fiber optic connector during the installation process or later (in which case it may be fixed there not only temporarily, but permanently), or insofar as the at least one fiber optic connector is only subsequently moved into its final position. c) Unwinding (releasing) the free end of the fiber optic cable, equipped with at least one fiber optic connector, from the cable supply of the fiber optic termination point to a length corresponding to the installation distance, leaving any remaining cable supply at the fiber optic termination point. Then, connecting the at least one fiber optic connector at the unwound free end of the cable to a fiber optic connector of the next fiber optic termination point. d) Repeat steps a) to c) while the OTO is not yet connected to the terminal device at the BEP.

[0013] The repetition of the preceding steps required according to step d) refers to the possibility that, depending on the structural conditions, several Flurboxes FBs may be cascaded between the fiber optic handover device at the BEP and an OTO or a Gf-TA, especially in multi-family houses, and thus installed according to the procedure described above.

[0014] If the at least one fiber optic connector at the end connected to the respective fiber optic termination device is only temporarily fixed inside it, it is moved into its final position after the length of fiber optic cable corresponding to the installation distance has been unwound from the cable supply (step c) or before it is coupled to another fiber optic connector. This final position can be inside the fiber optic termination device or accessible from the outside for coupling to another fiber optic connector.

[0015] In corridor boxes (FB) installed in public stairwells / hallways, the at least one fiber optic connector is regularly placed inside the fiber optic termination unit, even when in its final position, to prevent tampering. To protect against unauthorized access, the housing of the fiber optic termination unit (box) can be secured with a metric screw with a coded head, regardless of whether the at least one fiber optic connector is positioned before the required cable length is unwound from the cable supply or only afterward. This ensures that access to the at least one fiber optic connector is restricted to the installer.

[0016] As previously stated, each fiber optic termination point is provided with a cable length that exceeds the determined installation distance by a specified minimum. It is currently assumed that the cable length should be at least 10% longer than the determined installation distance. Based on existing practical experience with the local conditions in buildings being equipped with FTTH fiber optic cables, it is proposed that fiber optic termination points be provided with a cable length of 10 m or an integer multiple thereof. The cable length of an OTO (Optical Termination Unit) should therefore be at least 10 m, and that of a floor box (FB) at least 20 m. Floor boxes are used particularly in connection with FTTH deployment in apartment buildings or multi-unit buildings.They are preferably installed within the hallway or stairwell of multi-story apartment buildings or multi-party buildings.

[0017] Fiber optic termination units (OTOs) or fiber optic access points (FBs) may have a housing designed to accommodate, for example, due to tolerances, a length of cable exceeding the minimum specified length for that fiber optic termination unit by 10%. This means, for instance, that the housing of an OTO designated as having a 10 m cable length can actually accommodate 11 m of cable. Therefore, in the case of a specific construction project where the determined installation distance slightly exceeds 10 m (by a few centimeters), it could potentially be delivered with 11 m of cable. The same applies analogously to fiber optic termination units designed as floor boxes.

[0018] Based on the minimum cable lengths proposed above for OTOs and FBs (10 m for OTO, 20 m for FB) and the possibility of providing the fiber optic handover device with an integer multiple thereof, for example, OTOs with cable lengths of 10 m, 20 m, 30 m and 40 m and FBs with cable lengths of 20 m, 30 m, 40 m up to 40 + nx 10 m could be provided, whereby the cable length is wound up or coiled on a spool within the respective fiber optic handover device at least to the extent of its minimum length (10 m for OTO, 20 m for FB).In particular, variants with longer supply lengths can also be designed or provided in such a way that the cable supply is wound onto the spool inside the fiber optic transfer device only with a portion of its length, and is stored wound up outside the fiber optic transfer device with its remaining length, including the at least one fiber optic connector arranged at its free end, for transport.

[0019] The following describes possible structural situations at installation sites for FTTH deployment and possible configurations of the repeatedly mentioned fiber optic termination units (OTO and FB). The accompanying drawings provide explanations to facilitate a better understanding of the previously described procedure. The drawings show the following in detail: Fig. 1: an example of the conditions existing in an apartment building with regard to FTTH installation, Fig. 2: a possible form of training in the scenario according to the Fig. 1 fiber optic handover device used during FTTH installation, Fig. 3: one with the Fig. 2. A comparable form of training for a fiber optic handover device in a different view, Fig. 4: a modified version of the training format according to the Fig. 3.

[0020] The Fig.Figure 1 shows a schematic representation of a possible configuration for the conditions during FTTH deployment in an apartment building (Building 9). This scenario depicts the installation of fiber optic cables 5 to the premises of several customers / users on three floors of Building 9. A fiber optic connection was established between a fiber optic termination unit 4 at a building entry point (BEP 1) and a passive fiber optic termination unit 2 in the form of an optical network termination box (OTO) at each customer / user's premises. The fiber optic termination unit 4 located at the building entry point (BEP 1) is a termination device for an access network to the public wide area network.This is connected to the active technology of an OLT (Optical Line Terminal) in a (not shown here) Street Cabinet or a Central Office outside Building 9 and via this connected to the access network.

[0021] The focus of the presented solution, however, is, as already explained, the creation of the necessary fiber optic cable connections in the so-called network level 4, i.e., inside building 9, between the network termination device of the fiber optic handover device 4 at the building entry point BEP 1 and the fiber optic handover device 2, configured as a network termination box (OTO), at the respective customer / user's premises. As a fiber optic terminal adapter (FTA), the OTO enables a customer / user to connect their own equipment (CPE = Customer Premises Equipment) to use the wide area network. The customer / user can connect their own local network to the access network, for example, via a fiber optic cable connected to the FTA and an ONT (Optical Network Termination, such as a fiber optic modem, possibly combined with a router) connected to the other end of this cable. In the cases described in the Fig.The fiber optic handover devices 2, 3, 3` (OTO and FB) shown in Figure 1 are devices that serve as examples of an OTO and its design, as described below. Fig. 2, Fig. 3 to Fig. 4 will be explained.

[0022] The Fig. Figure 2 shows a possible embodiment of a fiber optic termination device 2, designed as an optical termination box (OTO), in a symbolic representation of its closed housing. An optical port 8 for connecting the customer's equipment via a fiber optic cable is located at the bottom right of the housing. Above this port, a section of a fiber optic cable 5 protrudes, the remaining length of which is contained within the housing of the OTO (fiber optic termination device 2) and is secured there by at least one fiber optic connector (not shown here).

[0023] According to the solution presented here, the fiber optic termination device 2 (OTO) shown is provided for the installation process during FTTH deployment with a cable supply 7, in which the fiber optic cable 5 forming this cable supply 7 is already connected at both ends. The fiber optic connector 6, located at the protruding free end of the fiber optic cable 5 or at the end of a fiber of this fiber optic cable 5, is visible in the illustration.

[0024] A corresponding fiber optic connector, not visible here, is also attached to the other end of the fiber optic cable 5, which is wound with its remaining length onto a spool inside the housing of the OTO (fiber optic termination unit 2). This fiber optic connector is fixed to the spool onto which the fiber optic cable is wound, so that the fiber optic cable 5 can be pulled out of the OTO with the rotating spool without twisting. For installation purposes, the fiber optic cable 5 is pulled out or unwound from the spool to a length corresponding to the previously determined installation distance. The fiber optic connector 6 on the free end of the cable pulled out of the OTO can then be connected, with regard to the Fig.1. The fiber optic cable can be connected either to a connector of a floor box FB (fiber optic termination unit 3) or (depending on local conditions) directly to the termination unit of the fiber optic termination unit 4 at the building entry point BEP 1. The externally accessible port 8 represents the final position into which the fiber optic connector, temporarily fixed inside the box (OTO = fiber optic termination unit 2) during the unwinding process, must be positioned after the length of cable corresponding to the installation distance has been unwound from the cable spool 7. To do this, it is detached from the spool and repositioned accordingly at the OTO.

[0025] The Fig. 3 shows one with the Fig. 2. Comparable form of design of an OTO or fiber optic handover device. 2. In the symbolic or schematic representation, the coil for the cable supply 7 inside the OTO is also indicated. Fig.Figure 4, in contrast, shows a modified version of the OTO (fiber optic termination unit 2), which is provided with a significantly longer cable length 7. In this version, 10 m of the corresponding cable length 7 are wound onto the spool inside the housing, whereas the remaining length of the cable length 7 is stored outside the housing of the fiber optic termination unit 2, namely wound around it.

[0026] The one in Fig. The floor boxes (FBs) shown in section 1 (fiber optic handover devices 3.3) have a connection to the one shown in the Fig. 2, Fig. 3 to Fig.The network termination boxes (OTO) shown in Figure 4 have a largely comparable design. However, for practical reasons, these are provided with a slightly larger cable length (a cable length of at least 20 m seems appropriate). The fiber optic termination boxes (FTs) can have a slightly larger housing and therefore accommodate a larger cable length (7) within their housing than comparable OTOs. To reduce the required cables and fibers, the fiber optic termination boxes (FTs) 3, 3' can also be equipped internally with a passive optical splitter.

Claims

[1] Method for FTTH installation of fiber optic cables (5) within a building (9), according to which a fiber optic connection is created in an installation process between a passive fiber optic termination device (4) arranged at a building entry point (BEP) (1) with a termination device for an access network to the public wide area network and at least one passive fiber optic termination device (2), which is designed as a fiber optic terminal adapter (FTA) in the form of an optical termination box (OTO) and enables the connection of customer-owned equipment (CPE) for the use of the wide area network, wherein the fiber optic connection is established over a variable route length between the fiber optic termination device (4) at the building entry point (BEP) (1) and the fiber optic termination device (2) either directly or via at least one further passive fiber optic termination device (3, 3') designed as a hallway box (FB), characterized by a.) Determining an installation distance, namely the length of fiber optic cable required for laying the cable between a fiber optic termination point (2, 3, 3') to be arranged at an installation location in the building (9) and the nearest fiber optic termination point (3, 3', 4) in the direction of the building entry point BEP (1), b.) Arranging the fiber optic termination device (2, 3, 3`) at the installation site, which is provided with a coiled cable supply (7) of a fiber optic cable (5) whose length exceeds the determined installation distance by a specified minimum amount, the fiber optic cable being provided at both ends with at least one fiber optic connector (6), namely one fiber optic connector (6) per fiber, and the fiber optic cable being at least temporarily fixed with at least one fiber optic connector at one of its ends inside the fiber optic termination device (2, 3, 3`), c.) Unwinding the free end of the fiber optic cable (5) equipped with at least one fiber optic connector (6) from the cable supply (7) of the fiber optic handover device (2, 3, 3`) to a length corresponding to the installation distance, leaving a remaining cable supply at the fiber optic handover device (2, 3, 3`), and coupling the at least one fiber optic connector (6) at the unwound cable end with a fiber optic connector of the next fiber optic handover device (3, 3`, 4), d.) Repeat steps a) to c) as long as there is still no fiber optic connection between the fiber optic termination device (2) designed as an optical network termination box (OTO) and the termination device of the fiber optic termination device (4) at the building entry point (BEP) (1), wherein the at least one fiber optic connector inside the respective fiber optic termination device (2, 3, 3'), insofar as it is only temporarily fixed there, is moved after step c) or before its coupling with another fiber optic connector into a fixed final position located inside this fiber optic termination device or accessible from the outside for coupling with another fiber optic connector. [2] Method according to claim 1, characterized by , that each fiber optic handover device (2, 3, 3`) is provided with a cable supply (7) whose length exceeds the determined installation distance by at least 10%. [3] Method according to claim 1 or 2, characterized by , that each fiber optic handover device (2, 3, 3`) is provided with a cable supply (7) which has a length of 10 m or an integer multiple thereof. [4] Method according to claim 3, characterized by , that each fiber optic handover point (2, 3, 3`) is provided with a cable supply (7) whose length exceeds the minimum length specified for the fiber optic handover point in question by 10%.

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