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WO2001086847A1 - Procede de controle de qualite et d"identite de canaux de transmission a une certaine longueur d"onde dans des reseaux de transmission optiques - Google Patents

Procede de controle de qualite et d"identite de canaux de transmission a une certaine longueur d"onde dans des reseaux de transmission optiques Download PDF

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Publication number
WO2001086847A1
WO2001086847A1 PCT/DE2001/001858 DE0101858W WO0186847A1 WO 2001086847 A1 WO2001086847 A1 WO 2001086847A1 DE 0101858 W DE0101858 W DE 0101858W WO 0186847 A1 WO0186847 A1 WO 0186847A1
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WO
WIPO (PCT)
Prior art keywords
quality
control signal
signal
transmission
frequency
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/DE2001/001858
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German (de)
English (en)
Inventor
Michael Rohde
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.)
Fraunhofer Institut fuer Nachrichtentechnik Heinrich Hertz Institute HHI
Original Assignee
Fraunhofer Institut fuer Nachrichtentechnik Heinrich Hertz Institute HHI
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 Fraunhofer Institut fuer Nachrichtentechnik Heinrich Hertz Institute HHI filed Critical Fraunhofer Institut fuer Nachrichtentechnik Heinrich Hertz Institute HHI
Publication of WO2001086847A1 publication Critical patent/WO2001086847A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
    • H04B10/0775—Performance monitoring and measurement of transmission parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0298—Wavelength-division multiplex systems with sub-carrier multiplexing [SCM]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2210/00—Indexing scheme relating to optical transmission systems
    • H04B2210/07—Monitoring an optical transmission system using a supervisory signal
    • H04B2210/078—Monitoring an optical transmission system using a supervisory signal using a separate wavelength

Definitions

  • optical transmission networks the data signals that are transmitted in very high density and at very high speed are degraded by the transport routes and the transmission components present in the networks.
  • Communication network users expect error-free data transmission.
  • the quality of the transmitted data must be checked continuously or at defined intervals to ensure that it is free of errors.
  • the quality of the data transmission must be determined at least before a transmission link is started up or put back into operation. It is also necessary to check the identity of wavelength channels in optical networks.
  • network management information e.g. for signaling or control purposes
  • a proven method for determining the signal quality is to determine the bit error rate (BER).
  • BER bit error rate
  • This method either a known data signal of sufficient length in which an error is likely to occur, or an error detection code is transmitted and the errors determined are counted.
  • the disadvantage of this method is in the large number of bits to be transmitted and evaluated, which means that this method is very time-consuming and no immediate (real-time) information about the quality of the data signals is possible.
  • Another disadvantage is that the broadband facilities that are required at high data rates are expensive.
  • this method cannot be used during the operating phase since a known signal must be transmitted instead of the useful signal.
  • histogram methods are used in which the useful signal is used to generate amplitude statistics, from which conclusions can be drawn about the useful signal quality and possible causes of interference.
  • Such a method is described in C.M. Weinert et al "Histogram method for identification and evaluation of crosstalk" (OFC 2000, Technical Digest, ThD5, pp. 56-58, 2000).
  • management information eg for signaling or controlling network elements
  • ECOC 99 Session In-band signaling Channel for all optical WDM networks
  • Nice, France CDMA method has been described.
  • a signaling signal is modulated onto the useful signal.
  • the data rate of the signaling channel is limited by the spread spectrum and the tolerable interference with the useful signal.
  • a statement about the quality of the useful signal cannot and should not be derived with this method; a statement about the identity would in principle be possible.
  • the object of the invention is to provide a method with which both identity indicators for identifying the respective wave length channel are transmitted as well as a statement on the transmission quality of the useful signal over an optical transmission path is made possible and signaling information is possibly transmitted to network components with the useful signal.
  • a low-rate control signal of a carrier frequency is modulated and added to the useful signal in an electrical frequency multiplexing method, the carrier frequency being selected immediately above the highest useful signal frequency relevant for the transmission.
  • the control signal is provided by a control signal transmitter and contains coded information for identifying the wavelength channels and for the quality assessment of the transmission link, as well as network management information, for example for controlling network elements. The sum signal is then coupled into the optical transmission network.
  • an optical transmission path which can be a part of an optical transmission path
  • a small part of the optical power for the evaluation of the control signal is coupled out of the sum signal at an optical network node or a network element.
  • a fast photodetector ensures opto-electrical conversion. Filtering and renewed frequency conversion means that the low-rate digital control signal is recovered and evaluated in terms of information content and quality in the digital receiver.
  • the information that is transmitted with the control signal serves on the one hand to identify the signal, ie to verify the optical switching functionality, and on the other hand to transmit network management information between network elements or between network management system and network elements.
  • the quality of the control signal ie the bit error frequency BER, is determined using conventional methods.
  • the quality of the useful signal is inferred from the quality of the control signal. Because the degradation effects on the optical transmission link impair the control signal more than the useful signal due to its higher frequency components, a "worst-case" estimate can be made of the quality of the control signal and the quality of the useful signal. A defined quality of the useful signal can thus always be ensured.
  • the advantage of this method is, in particular, that commercially available and inexpensive electronic components can be used for the generation and evaluation of the control signal, since it is modulated onto a narrow-band carrier frequency.
  • the determination z. B. the bit error rate of the low-rate control signal can be done much easier than for the broadband and high-rate useful signal. Since the transmission quality of the optical transmission link is determined on the basis of the quality of the control signal, this can, in addition to the continuous monitoring of the current useful signal during operation, also before start-up or recommissioning, e.g. B. after maintenance work of the network can be determined without transmitting a useful signal.
  • this method there is the possibility of concluding by increasing the carrier frequency of the control signal and evaluating the quality of the transmitted control signal that the useful signal frequency and thus the data rate can be increased with sufficient useful signal quality.
  • Another advantage of the inventive solution is that at any optical network node or network element within the optical transmission path, a small part of the optical power is decoupled from the sum signal for evaluating the control signal. In this way, the relevant information such as identity tags and network management information can be received and evaluated. The quality of the transmission path covered up to this point is determined at each of these network nodes or network elements, as a result of which the causes of errors in the optical transmission can be determined specifically and quickly.
  • FIG. 1 Schematic representation of a transmission link.
  • Fig. 2 useful signal and control signal in the RF spectrum.
  • Fig. 3 useful signal and control signal in the optical spectrum
  • the control signal 3 is provided by a control signal transmitter 3.1. It contains information that can be used to identify the useful signal 2, i.e. the verification of the optical switching functionality, as well as the determination of the transmission quality and possibly the network management, for example as signaling and control information for the network elements of an optical network.
  • the control signal 3 is modulated onto a carrier frequency in an RF modulator 3.3. The selected carrier frequency lies above the highest useful signal frequency relevant for the transmission.
  • the useful signal 2 is combined by an electrical frequency multiplexer 4.1 with the control signal 3 to form a sum signal 4.
  • This sum signal 4 is modulated by an optical modulator 5 to an optical carrier frequency provided by a laser and is coupled into the optical transmission network 1 at the feed-in point 1.1.
  • the optical signal is integrated into one by means of an optical demodulator 6 (eg photo receiver) electrical signal, the sum signal 4, consisting of useful signal 2 and control signal 3, converted.
  • the useful signal 2 and the control signal 3 are separated from the sum signal 4 in an electrical frequency demultiplexer 4.2.
  • the useful signal 2 is made available for further transmission purposes.
  • control signal 3 is transformed back into the baseband in an HF demodulator 3.4 and forwarded to the control signal receiver 3.2 for evaluation.
  • the information transmitted with the control signal 3 is evaluated using conventional methods and used for signal identification and optionally as network management information, for example as control information for network elements.
  • the quality of the control signal 3 received by the control signal receiver 3.2 is evaluated using known and customary methods for determining the bit error rate BER in order to be able to draw conclusions about the quality of the transmission link. Since the control signal 3 is narrowband and has a low data rate, the bit error rate BER can be determined with comparatively little effort. Conventional methods of channel coding or forward error correction (FEC) can be used to reliably transmit the information. These methods include error protection coding optimized for the respective channel, for which a certain additional capacity (overhead, redundancy) must be reserved in the respective data channel.
  • FEC forward error correction
  • a "worst-case estimate" can be carried out for the bit error rate of the useful signal 2 from the bit error rate of the control signal 3. That is, if the transmitted control signal 3 at the control signal receiver 3.2 is of sufficient quality, an adequate transmission quality of the useful signal 2 is ensured in any case.
  • the transmission quality does not have to be determined particularly quickly, since a trend can be recognized here and the error rate of the control signal always rises before the useful signal is impaired, so that appropriate measures can be initiated in good time.
  • the transmission quality of the optical transmission link 1 is determined on the basis of the determined quality of the transmitted control signal 3, this can also be determined without a useful signal 2 being transmitted must become. This method can therefore also be used before the start-up of a transmission link 1 in order to ensure the quality of the useful signal from the beginning.
  • the different carrier frequencies can be provided by means of a tunable RF modulator 3.3 or RF demodulator 3.4 or as graduated carrier frequencies by various fixed RF carriers.
  • the useful signal 2 shows the useful signal 2 and the control signal 3 in the HF spectrum as it is available as a sum signal 4 before the modulation onto the optical carrier frequency.
  • the electrical power density is plotted on a logarithmic scale.
  • the useful signal 2 covers a spectrum from 0 to approx. 9.75 GHz, while the control signal 3 has a frequency spectrum from approx. 9.75 to 10.25 GHz.
  • the control signal 3 is a low-rate signal that is modulated onto a carrier frequency that is selected above the highest useful signal frequency relevant for the transmission. In this example, the carrier frequency for the control signal 3 was chosen to be 10 GHz.
  • Above the control signal 3, a portion of the useful signal spectrum is shown that is not used for the transmission of the useful signal 2. This portion has a very high attenuation (between 10 and 40 dB). It can be filtered out of the HF spectrum by means of appropriately selected filters or attenuated even more so that it is practically no longer available.
  • the useful signal 2 and the control signal 3 in the optical spectrum shows the useful signal 2 and the control signal 3 in the optical spectrum, as it is coupled into the optical transmission link 1 as a sum signal 4 after the modulation onto the optical carrier frequency, shown.
  • the optical power density is plotted on a logarithmic scale. It is based on the optical carrier frequency (laser frequency) of 193.1 THz used.
  • the portion of the useful signal spectrum above the control signal 3 that is not used for the transmission of the useful signal 2 is also shown here. This portion has an even stronger attenuation here than in the HF spectrum. If this portion has already been filtered out of the HF spectrum, it is practically no longer present in the optical spectrum.
  • the main advantage in receiving and evaluating the control signal 3 is that, owing to the narrowband nature and low nature of the control signal 3, commercially available and inexpensive electronic components can be used.

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

Abstract

Pour garantir la qualité de la transmission de données, il faut que la qualité des données transmises soit contrôlée. En outre, le contrôle de l'identité de canaux de transmission à une certaine longueur d'onde ainsi que la transmission d'informations de gestion de réseau sont nécessaires. Selon l'invention, un signal de contrôle de faible débit est modulé sur une fréquence porteuse qui se trouve directement au-dessus de la fréquence de signal utile la plus élevée servant à la transmission, puis ajouté au signal utile selon un procédé de multiplexage en fréquence électrique, puis injecté en tant que signal total dans le réseau de transmission. Le signal de contrôle contient des informations pour la détermination de l'identité des canaux de transmission à une certaine longueur d'onde, pour l'évaluation de la qualité, ainsi que des informations de gestion de réseau.
PCT/DE2001/001858 2000-05-12 2001-05-11 Procede de controle de qualite et d"identite de canaux de transmission a une certaine longueur d"onde dans des reseaux de transmission optiques Ceased WO2001086847A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10024238A DE10024238B4 (de) 2000-05-12 2000-05-12 Verfahren zur Qualitäts-und Identitätskontrolle von Wellenlängenkanälen in optischen Übertragungsnetzen
DE10024238.3 2000-05-12

Publications (1)

Publication Number Publication Date
WO2001086847A1 true WO2001086847A1 (fr) 2001-11-15

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DE (1) DE10024238B4 (fr)
WO (1) WO2001086847A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1355441A1 (fr) * 2002-04-18 2003-10-22 Alcatel Procédé et système de contrôle de la transmission de signaux optiques

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10216279A1 (de) * 2002-04-12 2003-10-30 Siemens Ag Verfahren zur Detektion eines Kontrollsignals in einem optischen Übertragungssystem

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0782279A2 (fr) * 1995-12-27 1997-07-02 AT&T Corp. Entretien de résaux optiques

Family Cites Families (2)

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Publication number Priority date Publication date Assignee Title
DE19538755A1 (de) * 1995-10-18 1997-04-24 Bosch Gmbh Robert Überwachungs- und/oder Steuereinrichtung und -Verfahren
GB2314224A (en) * 1996-06-11 1997-12-17 Stc Submarine Systems Ltd Fibre optic transmission

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0782279A2 (fr) * 1995-12-27 1997-07-02 AT&T Corp. Entretien de résaux optiques

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
GAUDINO R ET AL: "MOSAIC: A MULTIWAVELENGTH OPTICAL SUBCARRIER MULTIPLEXED CONTROLLEDNETWORK", IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, IEEE INC. NEW YORK, US, vol. 16, no. 7, 1 September 1998 (1998-09-01), pages 1270 - 1285, XP000785944, ISSN: 0733-8716 *
HO K-P ET AL: "METHODS FOR CROSSTALK MEASUREMENT AND REDUCTION IN DENSE WDM SYSTEMS", JOURNAL OF LIGHTWAVE TECHNOLOGY, IEEE. NEW YORK, US, vol. 14, no. 6, 1 June 1996 (1996-06-01), pages 1127 - 1135, XP000598518, ISSN: 0733-8724 *
ROSSI G ET AL: "Optical performance monitoring in reconfigurable WDM optical networks using subcarrier multiplexing", JOURNAL OF LIGHTWAVE TECHNOLOGY, DEC. 2000, IEEE, USA, vol. 18, no. 12, December 2000 (2000-12-01), pages 1639 - 1648, XP002179167, ISSN: 0733-8724 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1355441A1 (fr) * 2002-04-18 2003-10-22 Alcatel Procédé et système de contrôle de la transmission de signaux optiques
FR2838901A1 (fr) * 2002-04-18 2003-10-24 Cit Alcatel Procede et systeme de controle de la transmission de signaux optiques
CN100338895C (zh) * 2002-04-18 2007-09-19 阿尔卡塔尔公司 光信号传送的控制方法和系统
US7295775B2 (en) 2002-04-18 2007-11-13 Alcatel Method and a system for monitoring the transmission of optical signals

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Publication number Publication date
DE10024238B4 (de) 2006-11-23
DE10024238A1 (de) 2002-01-03

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