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WO2002015439A1 - Systeme de communication a liaison a fibres optiques - Google Patents

Systeme de communication a liaison a fibres optiques Download PDF

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Publication number
WO2002015439A1
WO2002015439A1 PCT/SE2001/001768 SE0101768W WO0215439A1 WO 2002015439 A1 WO2002015439 A1 WO 2002015439A1 SE 0101768 W SE0101768 W SE 0101768W WO 0215439 A1 WO0215439 A1 WO 0215439A1
Authority
WO
WIPO (PCT)
Prior art keywords
master unit
repeater
unit
signals
optic
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/SE2001/001768
Other languages
English (en)
Inventor
Jesper Slettenmark
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.)
Allgon AB
Original Assignee
Allgon AB
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
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=20280731&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=WO2002015439(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Allgon AB filed Critical Allgon AB
Priority to AU2001280407A priority Critical patent/AU2001280407A1/en
Publication of WO2002015439A1 publication Critical patent/WO2002015439A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/08—Access point devices
    • H04W88/085—Access point devices with remote components
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2575—Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
    • H04B10/25752—Optical arrangements for wireless networks
    • H04B10/25753—Distribution optical network, e.g. between a base station and a plurality of remote units
    • H04B10/25755—Ring network topology

Definitions

  • the present invention concerns a cellular radio communication system of the kind including a base station with an associated master unit and a number of remotely located repeater units, which are connected to the master unit by means of fiber optical transmission cables, each repeater unit representing -a cell for wireless communication with mobile telephones.
  • Signal processing and communication control is carried out within the base station, whereas the repeater units only serve to amplify the communication signals and retransmit them in both directions to and from the mobile telephones.
  • Such a system is preferably used to achieve cellular coverage in radio shaded environments, such as in underground transport systems, large building structures, and the like.
  • the system is particularly advantageous when differently coded signals are carried by the same RF frequency, in particular code-division-mulptiple access (CDMA) signals, but may be used with any kind of information distribution scheme.
  • CDMA code-division-mulptiple access
  • US patent 6,025,944 discloses a fiber optic communication system which uses wavelength division multiplexing (WDM) as well as a code division multiple access (CDMA) format, in particular a hybrid device for transferring a multitude of communication signals at a very high rate.
  • WDM wavelength division multiplexing
  • CDMA code division multiple access
  • the system includes a number of ports, each being pro- vided with a coder and a decoder and being coupled to an associated fiber or fiber bundle in a network.
  • the present invention generally aims at providing a simple and inexpensive solution to the problem of distributing the RF- modulated optical signals between a master unit and a group of remotely located repeater units in a cellular communication system, which is particularly advantageous when the cellular communication system operates with differently coded signals carried by the same RF frequency. Specifically, it is an object to decrease the amount of fibers used in such a system.
  • This object is achieved for a system according to the invention wherein a single fiber optical transmission cable is connected between the master unit and a distribution network connected to the group of repeater units .
  • Mutually separated op- tical frequency bands are used for transferring RF-modulated optical signals between the master unit and the repeater units in the group, each optical frequency band corresponding to a particular repeater unit.
  • Corresponding splitting and filtering means are arranged at said master unit as well at each repeater unit.
  • the optic frequency bands used in the uplink may be identical to or separated from those used in the downlink.
  • the system according to the invention is rela- tively simple and inexpensive, since all components are passive devices except for the lasers and amplifiers. No complicated electrical multiplexing or signal processing devices are needed.
  • Fig. 1 shows schematically a system according to the invention, including a base station with a master unit coupled to a group of repeaters; and
  • Fig. 2 shows, in greater detail, the master unit and the repeaters of fig.l.
  • a part of a cellular system including a base station 1 with a master unit 2 and a group of four repeaters 3,4,5,6, one for each cell constituted by a local area to be served by the base station for wireless RF communication to and from mobile telephones located in the respective local area.
  • the base station 1 can be disposed adjacent to an underground railway system with tunnels and underground stations positioned along a transport line.
  • the base station 1 with the master unit 2 may then be located at one underground station, whereas the cell repeaters 3,4,5,6 are disposed at other underground stations, located at a distance from each other, typically one or several kilometers apart.
  • the base station 1 has separate cables 11,12,13,14, e.g. coaxial cables connected to the master unit 2, for communication to and from each repeater unit 3-6.
  • cables 11,12,13,14 e.g. coaxial cables connected to the master unit 2, for communication to and from each repeater unit 3-6.
  • fiber optical transmission cables are used for the transmission to and from the cell repeaters. Such cables can easily be installed in the tunnels between the underground stations .
  • the communication RF signals all have the same carrier frequency, e.g. CDMA signals (code division multiplex access) , and it is therefore a problem to filter out a particular signal intended for a given cell repeater, so as to avoid interference and disturbances from signals associated with other cells.
  • CDMA signals code division multiplex access
  • this problem is solved by using mutually separated optical frequency bands for transferring the RF-modulated optical signals through a single fiber optical transmission cable between the master unit 1 and the repeater units 3-6.
  • these cables are de- noted 15,16,17 and 18 and are typically disposed in a respective tunnel between two underground stations .
  • the single fiber optical transmission cable 15,16,17 and 18, respectively, must carry communication signals in both direc- tions, and it is therefore necessary to insert corresponding splitting and filtering means in the master unit 1 as well as at each repeater unit 3-6.
  • an optic splitter 21 is arranged in the master unit 2 so as to connect the single fiber optical transmission cable to first and second master unit branches 22,23.
  • the first master unit branch 22 is a downlink branch provided with an optical isolator 24 which attenuates signals propagating in the uplink direction.
  • the signals propagating in the downlink direction are carried by optical waves generated by a number of lasers 25,26,27,28, each being associated with a corresponding cell repeater 3,4,5,6, respectively, and having a specific frequency or wavelength.
  • a number of optical splitters 29,30,31 are used.
  • the RF signals which are transmitted from the base station on the coaxial cables 11,12,13,14 and are designated for the different cell repeaters 3,4,5,6, are modulated onto the optical signals generated by the lasers 25,26,27,28 in the master unit 2.
  • the separated frequency bands correspond to the wavelengths 1510 n , 1530 nm, 1550 nm, and 1570 nm, respectively.
  • the lasers are of single mode type, e.g. a distributed feed back laser generating a well-defined wavelength with relatively low temperature drift (less than O.lnm per degree) .
  • the other master unit branch 23 is an uplink branch having a number of optical band pass filters 32,33 and 34 connected to four optical receivers 35,36,37,38.
  • Each repeater unit includes an optical splitter 46,47,48 and 49, respectively, an optic isola- tor 50,51,52 and 53, respectively, and a laser 54,55,56 and 57, respectively, for generating a specific optical carrier wave in the uplink direction.
  • Each optical splitter 46,47,48,49 is also connected to an associated optical receiver 58,59,60,61.
  • the four RF signals from the base station 1 are modu- lated onto optical carrier waves generated in the master unit lasers 25,26,27,28 and are transferred through the single fiber transmission cable 15. These modulated signals are separated in the optical pass band filters 39,40,41 and are transferred to the associated receivers 58,59,60,61, where the res- pective RF signals are demodulated, amplified and transmitted via associated antennas (not shown) to any mobile telephones possibly being located in the local areas surrounding the cell repeaters 3,4,5,6.
  • the RF-modulated optical signal is transferred via the associated isolator, the optical splitter, the network branch and the single fiber optical transmission cable 15 to the master unit 2. In the latter, the optical signal will be transferred to one of the receivers 35,36,37,38, where it is demo- dulated and forwarded to the base station via the associated coaxial cable 11,12,13 or 14 (fig. 1).
  • signals transmitted between the master unit and one of the repeaters are modulated on one optical carrier frequency, which is the same in the downlink and the uplink but totally separated from the optical carrier frequencies used for transmission of information between the master unit and all other repeaters.
  • the optical carrier frequency for transmission from the master unit to one specific repeater i.e. in the downlink
  • These two optical carrier frequencies are then totally separated from all other optical carrier frequencies transmitted through the single fiber transmission cable 15.
  • the isolators 24,50,51,52,53 can be dispensed with in case the associated lasers have built in isolating means .

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Optical Communication System (AREA)

Abstract

L'invention porte sur un système de communication radiocellulaire comprenant une station de base (1) pourvue d'une unité maître associée (2) qui est raccordée par des câbles de fibres optiques (15, 16, 17, 18) à une quantité d'unités de répétition à distance (3, 4, 5, 6). Des signaux codés sont distribués sous forme de signaux optiques à modulation HF par un câble unique de transmission de fibres optiques (15) raccordé entre l'unité maître (2) et un réseau de distribution (15, 42, 16, 43, 17, 44, 18) à son tour raccordé aux unités de répétition (3, 4, 5, 6). Un premier ensemble de bandes de fréquence optiques séparées, spécifiques, sont utilisées pour transférer des signaux optiques à modulation HF de l'unité maître (2) aux unités de répétition (3, 4, 5, 6), tandis qu'un second ensemble de bandes de fréquence optiques sont utilisées pour transférer des signaux dans le sens opposé. Chaque bande de fréquence optique de chaque ensemble correspond à une unité de répétition spécifique. Les premier et second ensembles de bandes de fréquence optiques peuvent être séparés l'un de l'autre ou identiques l'un à l'autre.
PCT/SE2001/001768 2000-08-18 2001-08-17 Systeme de communication a liaison a fibres optiques Ceased WO2002015439A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2001280407A AU2001280407A1 (en) 2000-08-18 2001-08-17 Communication system with fiber optical link

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0002948A SE523506C2 (sv) 2000-08-18 2000-08-18 Kommunikationssystem med fiberoptisk länk
SE0002948-8 2000-08-18

Publications (1)

Publication Number Publication Date
WO2002015439A1 true WO2002015439A1 (fr) 2002-02-21

Family

ID=20280731

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2001/001768 Ceased WO2002015439A1 (fr) 2000-08-18 2001-08-17 Systeme de communication a liaison a fibres optiques

Country Status (3)

Country Link
AU (1) AU2001280407A1 (fr)
SE (1) SE523506C2 (fr)
WO (1) WO2002015439A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1339179A3 (fr) * 2002-02-26 2004-12-22 Matsushita Electric Industrial Co., Ltd. Système de transmission optique bidirectionnel et stations maítres et esclaves associés

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0448832A (ja) * 1990-06-18 1992-02-18 A T R Koudenpa Tsushin Kenkyusho:Kk 光リンク無線通信方式
US5377035A (en) * 1993-09-28 1994-12-27 Hughes Aircraft Company Wavelength division multiplexed fiber optic link for RF polarization diversity receiver
JPH08191478A (ja) * 1995-01-11 1996-07-23 Nec Corp 光ネットワークおよび無線基地局
EP0994582A1 (fr) * 1998-10-15 2000-04-19 Lucent Technologies Inc. Réseau reconfigurable à fibres optiques pour la communication sans fil

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0448832A (ja) * 1990-06-18 1992-02-18 A T R Koudenpa Tsushin Kenkyusho:Kk 光リンク無線通信方式
US5377035A (en) * 1993-09-28 1994-12-27 Hughes Aircraft Company Wavelength division multiplexed fiber optic link for RF polarization diversity receiver
JPH08191478A (ja) * 1995-01-11 1996-07-23 Nec Corp 光ネットワークおよび無線基地局
EP0994582A1 (fr) * 1998-10-15 2000-04-19 Lucent Technologies Inc. Réseau reconfigurable à fibres optiques pour la communication sans fil

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
FUTAKATA TOSHIYUKI ET AL.: "Noise reduction device using novel automatic wavelength-offset control for highly stable optical-microwave transmission systems", IEICE TRANS. ELECTRON., vol. E79-C, no. 5, May 1996 (1996-05-01), pages 657 - 663 *
KAJIYA SATOSHI ET AL.: "Proposal of fiber-optic radio highway networks using CDMA method", 1995 FOURTH IEEE INTERNATIONAL CONFERENCE ON UNIVERSAL PERSONAL COMMUNICATIONS, 1995, pages 496 - 500 *
PATENT ABSTRACTS OF JAPAN *
SMITH G.H. ET AL.: "A millimeter-wave full-duplex fiber-radio star-tree architecture incorporating WDM and SCM", IEE PHOTONICS TECHNOLOGY LETTERS, vol. 10, no. 11, November 1998 (1998-11-01), pages 1650 - 1652 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1339179A3 (fr) * 2002-02-26 2004-12-22 Matsushita Electric Industrial Co., Ltd. Système de transmission optique bidirectionnel et stations maítres et esclaves associés
EP1605614A1 (fr) * 2002-02-26 2005-12-14 Matsushita Electric Industrial Co., Ltd. Système de transmission optique bidirectionnel et stations maítres et esclaves associés

Also Published As

Publication number Publication date
SE0002948D0 (sv) 2000-08-18
AU2001280407A1 (en) 2002-02-25
SE0002948L (sv) 2002-02-19
SE523506C2 (sv) 2004-04-27

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