WO2018178389A1 - Dropwire - Google Patents

Dropwire Download PDF

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Publication number
WO2018178389A1
WO2018178389A1 PCT/EP2018/058424 EP2018058424W WO2018178389A1 WO 2018178389 A1 WO2018178389 A1 WO 2018178389A1 EP 2018058424 W EP2018058424 W EP 2018058424W WO 2018178389 A1 WO2018178389 A1 WO 2018178389A1
Authority
WO
WIPO (PCT)
Prior art keywords
dropwire
strength members
pair
conductors
copper
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2018/058424
Other languages
French (fr)
Inventor
Christopher MUNNINGS
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
British Telecommunications PLC
Original Assignee
British Telecommunications PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by British Telecommunications PLC filed Critical British Telecommunications PLC
Publication of WO2018178389A1 publication Critical patent/WO2018178389A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B11/00—Communication cables or conductors
    • H01B11/007—Communication cables or conductors for overhead application
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/18—Protection against damage caused by wear, mechanical force or pressure; Sheaths; Armouring
    • H01B7/185—Sheaths comprising internal cavities or channels
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B11/00—Communication cables or conductors
    • H01B11/02—Cables with twisted pairs or quads
    • H01B11/06—Cables with twisted pairs or quads with means for reducing effects of electromagnetic or electrostatic disturbances, e.g. screens
    • H01B11/08—Screens specially adapted for reducing cross-talk
    • H01B11/085—Screens specially adapted for reducing cross-talk composed of longitudinal tape conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/18—Protection against damage caused by wear, mechanical force or pressure; Sheaths; Armouring
    • H01B7/22—Metal wires or tapes, e.g. made of steel
    • H01B7/221—Longitudinally placed metal wires or tapes
    • H01B7/225—Longitudinally placed metal wires or tapes forming part of an outer sheath

Definitions

  • the present invention relates to a dropwire for use in an access network, and in particular to a dropwire for use in a hybrid fibre-copper access network.
  • Asymmetric Digital Subscriber Line (ADSL) technology over existing copper wires can provide data rates of up to 24 Mbit/s, but many customers will experience significantly lower data rates due to the length of the network connection.
  • FTTP Fibre to the Premises
  • PONs Passive Optical Networks
  • FIG. 1 shows a schematic depiction of a hybrid fibre-copper access network 100 in which a telephone exchange 1 10 is connected to a plurality of customer premises 500 (the customer premises may be domestic, commercial or industrial premises).
  • One network architecture is Fibre to the Cabinet (FTTC [or FTTCab]), in which the telephone exchange 1 10 is connected to cabinets 120 by optical fibre cable 1 15.
  • FTTC Fibre to the Cabinet
  • VDSL Very-high-bit-rate Digital Subscriber Line
  • the customer premises are connected to the cabinet via a distribution point 130, which is typically located near to the customer premises, for example at a telephone pole.
  • the distribution point is typically connected to the customer premises 500 using a dropwire 135, via a telephone pole (not shown).
  • a further network architecture is Fibre to the Node (FTTN) in which optical fibre is installed to the distribution point and the opto-electronic conversion of signals takes place in a node which is located at the distribution point. Electrical data signals are then transmitted from the node to the user, via the dropwire.
  • FTTN Fibre to the Node
  • the dropwire needs to be mechanically robust enough to withstand the additional loads caused by ice formation on the dropwire and/or high winds. However, it is important that the dropwire is not too strong. In the event that a dropwire is struck by a tall vehicle it is desirable that dropwire effectively acts as a mechanical fuse, such that it breaks before the mechanical load becomes sufficient to damage the telephone pole and/or the building to which the dropwire is connected.
  • Figure 2 shows a schematic depiction of the cross-section of a conventional dropwire 200 which comprises a pair of copper conductors 210, a plurality of steel strength members 220 and a ripcord 230, all of which are received within a sheath 240.
  • the pair of copper conductors are preferably received within a plastic film 250 such that they are separated from the other dropwire components.
  • the copper conductors 210 will have a slight twist imposed on them during the cable manufacturing process.
  • Each of the plurality of steel strength members will be formed from a plurality of strands.
  • New data transmission technologies such as G.fast enable downstream data rates of up to 1 Gbit/s to be transmitted over the copper portion of a hybrid fibre-copper access network, such as FTTC or FTTN network, dependent on the length of the copper link length.
  • FTTC hybrid fibre-copper access network
  • Previous deployments of VDSL over FTTC networks have provided downstream data rates of up to 80 Mbit/s.
  • G.fast provides greater data throughput, in part, through the use of higher frequencies than those used in VDSL. It has been observed that at high data rates the losses in conventional dropwires increase such that the very high bit- rates associated with G.fast cannot be delivered reliably and consistently.
  • a dropwire for use in an access network comprising:
  • a body a plurality of metallic strength members and a pair of metallic conductors adapted for carrying data signals characterised in that the pair of metallic conductors are located substantially near to the longitudinal axis of the dropwire and the plurality of metallic strength members are located within the body away from the longitudinal axis of the dropwire.
  • the dropwire may comprise two strength members.
  • the body of the dropwire may comprise a void formed substantially near to the central axis of the dropwire and the pair of metallic conductors are received within the void.
  • the two strength members may be located such that one strength member is located on each side of the void.
  • Each of the plurality of strength members may comprise multiple stranded elements.
  • the dropwire body may comprise medium density polyethylene.
  • Figure 1 shows a shows a schematic depiction of a hybrid fibre-copper access network
  • Figure 2 shows a schematic depiction of the cross-section of a conventional dropwire
  • Figure 3 shows a schematic depiction of the cross-section of a dropwire according to the present invention.
  • Figure 4 shows a graphical depiction of the transmission loss for a dropwire.
  • FIG. 3 shows a schematic depiction of the cross-section of a dropwire 300 according to the present invention.
  • the dropwire 300 comprises a body 340 which is formed around a pair of twisted copper conductors 310.
  • the pair of twisted copper conductors 310 are received at, or near to, the central axis of the dropwire.
  • the copper conductors are each preferably 0.5mm copper wires, covered with an appropriate insulating material.
  • the dropwire comprises a pair of strength members 320a 320b, which are received within the dropwire body such that they are away from the central axis of the dropwire.
  • the pair of strength members 320a 320b preferably comprise three steel wires, each of diameter 0.32mm, wound around each other.
  • the strength members are located on opposite sides of the copper conductors.
  • the body of the dropwire may be formed directly over the pair of twisted copper conductors, or the body may comprise a void 370 within which the pair of twisted copper conductors can be received.
  • the inner surface 360 of the dropwire body which defines the void may be coated in a layer of a material which comprises anti- static carbon black particles.
  • the dropwire may comprise three, or more, strength members received within the dropwire body.
  • the body preferably comprises medium density polyethylene (MDPE) although it will be understood that other suitable materials could be used.
  • MDPE medium density polyethylene
  • the Applicant's earlier application EP - A 0 432 171 provides teaching on materials which can be used in similar transmission lines.
  • LDPE low density polyethylene
  • HDPE high density polyethylene
  • Figure 4 shows a graphical depiction of the transmission loss for a dropwire according to the present invention and a conventional dropwire (that is, one described above with reference to Figure 2) for an installed length of 50m of dropwire.
  • the upper trace shows the loss in the dropwire according to the present invention
  • the lower trace shows the loss in a conventional dropwire.
  • a dropwire for use in an access network such as a hybrid fibre-copper access network, in which the dropwire comprises a central bore, defined by the dropwire body, in which a pair of conductors are received.
  • the strength members are received within the body of the dropwire and are remote from the conductors.
  • Such a cable design reduces the electromagnetic interference which can be generated when using conventional dropwires.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Communication Cables (AREA)
  • Insulated Conductors (AREA)

Abstract

A dropwire for use in an access network, such as a hybrid fibre-copper access network, in which the dropwire comprises a central bore, defined by the dropwire body, in which a pair of conductors are received. The strength members are received within the body of the dropwire and are remote from the conductors. Such a cable design reduces the electromagnetic interference which can be generated when using conventional dropwires.

Description

DROPWIRE
Field of the Invention
The present invention relates to a dropwire for use in an access network, and in particular to a dropwire for use in a hybrid fibre-copper access network.
Background to the Invention
Since the advent of the World Wide Web, there has been a need to provide internet access to customers at ever increasing data rates. Asymmetric Digital Subscriber Line (ADSL) technology over existing copper wires can provide data rates of up to 24 Mbit/s, but many customers will experience significantly lower data rates due to the length of the network connection. One solution is to install Fibre to the Premises (FTTP) networks, such as PONs (Passive Optical Networks), but this approach requires very significant investment.
Another approach is to install limited amounts of optical fibre and to utilise it in conjunction with the legacy copper cabling. Figure 1 shows a schematic depiction of a hybrid fibre-copper access network 100 in which a telephone exchange 1 10 is connected to a plurality of customer premises 500 (the customer premises may be domestic, commercial or industrial premises). One network architecture is Fibre to the Cabinet (FTTC [or FTTCab]), in which the telephone exchange 1 10 is connected to cabinets 120 by optical fibre cable 1 15. VDSL (Very-high-bit-rate Digital Subscriber Line) data signals can be transmitted over the fibre cable to equipment in the cabinet which converts the optical signal to an electrical signal which can then be transmitted over a copper cable 125 to the customer premises 500. The customer premises are connected to the cabinet via a distribution point 130, which is typically located near to the customer premises, for example at a telephone pole. The distribution point is typically connected to the customer premises 500 using a dropwire 135, via a telephone pole (not shown). A further network architecture is Fibre to the Node (FTTN) in which optical fibre is installed to the distribution point and the opto-electronic conversion of signals takes place in a node which is located at the distribution point. Electrical data signals are then transmitted from the node to the user, via the dropwire.
The dropwire needs to be mechanically robust enough to withstand the additional loads caused by ice formation on the dropwire and/or high winds. However, it is important that the dropwire is not too strong. In the event that a dropwire is struck by a tall vehicle it is desirable that dropwire effectively acts as a mechanical fuse, such that it breaks before the mechanical load becomes sufficient to damage the telephone pole and/or the building to which the dropwire is connected.
Figure 2 shows a schematic depiction of the cross-section of a conventional dropwire 200 which comprises a pair of copper conductors 210, a plurality of steel strength members 220 and a ripcord 230, all of which are received within a sheath 240. The pair of copper conductors are preferably received within a plastic film 250 such that they are separated from the other dropwire components. The copper conductors 210 will have a slight twist imposed on them during the cable manufacturing process. Each of the plurality of steel strength members will be formed from a plurality of strands.
New data transmission technologies such as G.fast enable downstream data rates of up to 1 Gbit/s to be transmitted over the copper portion of a hybrid fibre-copper access network, such as FTTC or FTTN network, dependent on the length of the copper link length. Previous deployments of VDSL over FTTC networks have provided downstream data rates of up to 80 Mbit/s. G.fast provides greater data throughput, in part, through the use of higher frequencies than those used in VDSL. It has been observed that at high data rates the losses in conventional dropwires increase such that the very high bit- rates associated with G.fast cannot be delivered reliably and consistently.
It was assumed that the losses were due to electro-magnetic interference which was caused by the presence of the steel strength members in the dropwire. A new dropwire design was tested with the steel strength members being replaced by glass-fibre plastics
(GRP) strength members. Whilst the observed transmission losses decreased, due to decreased levels of electromagnetic interference, the new dropwire design did not have sufficient mechanical strength for it to be deployed in a network. Summary of the Invention
According to a first aspect of the invention, there is provided a dropwire for use in an access network, the dropwire comprising:
a body, a plurality of metallic strength members and a pair of metallic conductors adapted for carrying data signals characterised in that the pair of metallic conductors are located substantially near to the longitudinal axis of the dropwire and the plurality of metallic strength members are located within the body away from the longitudinal axis of the dropwire..
The dropwire may comprise two strength members. The body of the dropwire may comprise a void formed substantially near to the central axis of the dropwire and the pair of metallic conductors are received within the void. The two strength members may be located such that one strength member is located on each side of the void. Each of the plurality of strength members may comprise multiple stranded elements. The dropwire body may comprise medium density polyethylene.
Brief Description of the Figures
In order that the present invention may be better understood, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings in which:
Figure 1 shows a shows a schematic depiction of a hybrid fibre-copper access network;
Figure 2 shows a schematic depiction of the cross-section of a conventional dropwire;
Figure 3 shows a schematic depiction of the cross-section of a dropwire according to the present invention; and
Figure 4 shows a graphical depiction of the transmission loss for a dropwire. Detailed Description of Embodiments
Figure 3 shows a schematic depiction of the cross-section of a dropwire 300 according to the present invention. The dropwire 300 comprises a body 340 which is formed around a pair of twisted copper conductors 310. The pair of twisted copper conductors 310 are received at, or near to, the central axis of the dropwire. The copper conductors are each preferably 0.5mm copper wires, covered with an appropriate insulating material. The dropwire comprises a pair of strength members 320a 320b, which are received within the dropwire body such that they are away from the central axis of the dropwire. The pair of strength members 320a 320b preferably comprise three steel wires, each of diameter 0.32mm, wound around each other. As shown in Figure 3, preferably the strength members are located on opposite sides of the copper conductors. The body of the dropwire may be formed directly over the pair of twisted copper conductors, or the body may comprise a void 370 within which the pair of twisted copper conductors can be received. In the latter case, the inner surface 360 of the dropwire body which defines the void may be coated in a layer of a material which comprises anti- static carbon black particles.
It will be understood that variants of the dropwire described above with reference to Figure 3 will fall within the scope of the present invention. For example, the dropwire may comprise three, or more, strength members received within the dropwire body. The body preferably comprises medium density polyethylene (MDPE) although it will be understood that other suitable materials could be used. The Applicant's earlier application EP - A 0 432 171 provides teaching on materials which can be used in similar transmission lines. LDPE (low density polyethylene) may be used although there is a risk that higher tensile loads may lead to the cable stretching (or breaking). HDPE (high density polyethylene) may be used but the increased hardness will make it more difficult for technicians to cut and manipulate the cable during installation and maintenance processes.
Figure 4 shows a graphical depiction of the transmission loss for a dropwire according to the present invention and a conventional dropwire (that is, one described above with reference to Figure 2) for an installed length of 50m of dropwire. The upper trace (shown by the solid line) shows the loss in the dropwire according to the present invention and the lower trace (shown by the dashed line) shows the loss in a conventional dropwire. In summary, there is provided a dropwire for use in an access network, such as a hybrid fibre-copper access network, in which the dropwire comprises a central bore, defined by the dropwire body, in which a pair of conductors are received. The strength members are received within the body of the dropwire and are remote from the conductors. Such a cable design reduces the electromagnetic interference which can be generated when using conventional dropwires.

Claims

1 . A dropwire (300) for use in an access network, the dropwire comprising:
a body (340), a plurality of metallic strength members (320) and a pair of metallic conductors (310) adapted for carrying data signals wherein the pair of metallic conductors are located substantially near to the longitudinal axis of the dropwire and characterised in that the plurality of metallic strength members are located within the body, away from the longitudinal axis of the dropwire..
2. A dropwire according to Claim 1 , wherein the dropwire comprises 2 strength members (320a, 320b).
3. A dropwire according to any preceding Claim wherein the body comprises a void (370) formed substantially near to the central axis of the dropwire and the pair of metallic conductors are received within the void.
4. A dropwire according to Claim 3 when dependent on Claim 2 wherein the strength members are located on either side of the void.
5. A dropwire according to any preceding Claim wherein each of the plurality of strength members comprises multiple stranded elements.
6. A dropwire according to any preceding Claim wherein the body comprises medium density polyethylene.
PCT/EP2018/058424 2017-03-31 2018-04-03 Dropwire Ceased WO2018178389A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB1705224.2A GB2560987A (en) 2017-03-31 2017-03-31 Dropwire
GB1705224.2 2017-03-31

Publications (1)

Publication Number Publication Date
WO2018178389A1 true WO2018178389A1 (en) 2018-10-04

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ID=58682520

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PCT/EP2018/058424 Ceased WO2018178389A1 (en) 2017-03-31 2018-04-03 Dropwire

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WO (1) WO2018178389A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6509526B2 (en) * 2000-07-07 2003-01-21 Servicies Conoumex S.A. Dec.V. Telephone lead-in cable for ordinary voice service and high performance data and video transmission services
US20050126817A1 (en) * 2003-12-11 2005-06-16 Arzate Fermin M. Overhead and underground telephone lead-in cable for voice, data and video transmission services
US20140137974A1 (en) * 2012-11-16 2014-05-22 3M Innovative Properties Company Adhesive backed cabling system
US20140241677A1 (en) * 2011-08-04 2014-08-28 Ralph Sutehall Multipurpose optical fibre drop cable
US9116322B1 (en) * 2012-12-13 2015-08-25 Superior Essex International LP Cables including strength members that limit jacket elongation

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4801764A (en) * 1986-02-11 1989-01-31 Cooper Industries, Inc. Cable assembly for use under carpeting
US20100104126A1 (en) * 2008-10-24 2010-04-29 Andrea Martina Greene Tangle resistant audio cord and earphones
US9728302B1 (en) * 2016-09-30 2017-08-08 Superior Essex International IP Flame retardant communication cables incorporating extinguishants

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6509526B2 (en) * 2000-07-07 2003-01-21 Servicies Conoumex S.A. Dec.V. Telephone lead-in cable for ordinary voice service and high performance data and video transmission services
US20050126817A1 (en) * 2003-12-11 2005-06-16 Arzate Fermin M. Overhead and underground telephone lead-in cable for voice, data and video transmission services
US20140241677A1 (en) * 2011-08-04 2014-08-28 Ralph Sutehall Multipurpose optical fibre drop cable
US20140137974A1 (en) * 2012-11-16 2014-05-22 3M Innovative Properties Company Adhesive backed cabling system
US9116322B1 (en) * 2012-12-13 2015-08-25 Superior Essex International LP Cables including strength members that limit jacket elongation

Also Published As

Publication number Publication date
GB201705224D0 (en) 2017-05-17
GB2560987A (en) 2018-10-03

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