Patent Application
20150063815
1. Field
The present invention relates to fiber optic demarcation units and, more particularly, to fiber optic demarcation units for use in fiber-to-the-antenna (FTTA) systems.
2. Background
Radio networks use radio transceivers elevated by radio towers to broadcast or receive radio signals. Conventionally, coaxial cable operatively couples the radio transceiver to communication equipment on the ground. Coaxial cable has a large diameter, for example, about ½ inch to ¾ inch, and is heavy, which makes installation difficult. Coaxial cable also has high power consumption. Accordingly, there is need for radio networks that are easier to install and have improved power consumption.
In some embodiments, a FTTA system comprises a multi-fiber cable configured to be operatively coupled to fiber optic equipment on the ground. The FTTA system also comprises a fiber optic demarcation unit optically coupled to the multi-fiber cable, and a multi-fiber jumper cable comprising a push-pull connector at one end configured to be optically coupled to the fiber optic demarcation unit. Additionally, the FTTA system comprises a remote radio head optically coupled to the adapter of the fiber optic demarcation unit.
In some embodiments, a FTTA system comprises a multi-fiber cable operatively coupled to fiber optic equipment on the ground. The fiber optic demarcation unit is optically coupled to the multi-fiber cable and to a remote radio head. The fiber optic demarcation unit comprises a housing and a strain relief device attached to the housing and to the multi-fiber cable such that a load of the multi-fiber cable is transferred from an interface between the multi-fiber cable and the housing of the fiber optic demarcation unit.
In some embodiments, a housing for a fiber optic demarcation unit in a fiber-to-the-antenna system comprises a first housing portion comprising a first wall, a side wall extending from an edge of the first wall, and a mounting flange extending outward from the side wall. The side wall defines a port for holding an adapter. The housing also comprises a second housing portion comprising a second wall. The first housing portion and the second housing portion are configured to be coupled to create an environmental seal.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts.
While the invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those skilled in the art with access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the invention would be of significant utility.
Demarcation unit 101 comprises a housing 102 that encloses optical components. In some embodiments, housing 102 defines an environmentally sealed cavity for housing the optical components. Housing 102 may comprise two or more separate housing portions. For example, as shown in
Demarcation unit 101 is optically coupled to a multi-fiber cable 107. Cable 107 can comprise two or more fibers. For example, cable 107 can comprise twelve fibers. Cable 107 may comprise less than twelve fibers or more than twelve fibers. Cable 107 is optically coupled to fiber optic equipment on the ground, for example, an access terminal or electronic equipment in a ground enclosure proximate to the radio tower.
In some embodiments, cable 107 is fixedly coupled to demarcation unit 101. For example, cable 107 is fixedly coupled to demarcation unit 101 using a packing (PG) gland. In some embodiments, cable 107 is selectively coupled to demarcation unit 101. For example, demarcation unit 101 can comprise an adapter configured to optically couple with a connectorized end of cable 107. Cable 107 runs from the ground and vertically up a radio tower to the location of demarcation unit 101. In some embodiments, cable 107 has a diameter that ranges between about 3 mm to about 6 mm.
Demarcation unit 101 comprises one or more ports 108. As shown in
At each port 108, demarcation unit 101 can comprise an adapter 110. Each adapter 110 is optically coupled to two or more fibers of cable 107. Adapters 110 are configured to couple to a connectorized end of a jumper cable 112. Adapters 110 can be configured to create an environmental seal with the connectorized ends of jumper cables 112. For example, in some embodiments, adapters 110 can be configured to create a water-tight seal with a push-pull connector at one end of jumper cables 112. Each jumper cable 112 is optically coupled to one radio head 114. Jumper cables 112 run from demarcation unit 101 to radio head 114. The ends of jumper cables 112 opposite demarcation unit 101 can be spliced with remote radio heads 114 or can have connectors configured to optically couple to an adapter 115 of the remote radio heads 114. In some embodiments, jumper cables 112 are multi-fiber cables that each comprise two or more fibers.
In some embodiments, housing 102 defines an opening 116 configured to allow a user to handle or secure demarcation unit 101. In some embodiments, second housing portion 106 defines a rectangular opening 116 as shown in
In some embodiments, housing 102 defines one or more openings 118 configured to allow a fastening device to pass through. The fastening device(s) couple demarcation unit 101 to a radio tower or other desired location. As shown in
In some embodiments, demarcation unit 101 includes a strain relief device 120. Strain relief device 120 may be a cord, cable, rope, thread, or any other suitable strain relief device. Strain relief device 120 is coupled to housing 102 of demarcation unit 101 and to a point 121 of cable 107 such that the load of cable 107 is transferred away from the interface between housing 102 and cable 107. In some embodiments, location 121 may be about two feet away from housing 102.
In some embodiments, optical component 224 can be a wavelength division multiplexer configured to split the fibers of cable 107 into separate fibers or smaller bundles of two or more fibers, each transmitting an optical signal of a different wavelength. In some embodiments, in which optical component 224 is a wavelength division multiplexer, cable 107 can include only two fibers.
First housing portion 104 comprises an outer wall 223 and side wall 225 extending from the outer wall 223. Side wall 225 defines one or more ports 108. For example, as seen in
While an illustrative embodiment of the invention has been described above, it is, of course, understood that various modifications will be apparent to those of ordinary skill in the art. Such modifications are within the spirit and scope of the invention, which is limited and defined only by the appended claims.
