WO1992020179A1 - Procede et agencement pour la modulation differentielle de signaux dans un systeme de transmission a canaux multiples - Google Patents

Procede et agencement pour la modulation differentielle de signaux dans un systeme de transmission a canaux multiples Download PDF

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Publication number
WO1992020179A1
WO1992020179A1 PCT/EP1992/000841 EP9200841W WO9220179A1 WO 1992020179 A1 WO1992020179 A1 WO 1992020179A1 EP 9200841 W EP9200841 W EP 9200841W WO 9220179 A1 WO9220179 A1 WO 9220179A1
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WO
WIPO (PCT)
Prior art keywords
data
subcarrier
subcarriers
frequency
arrangement
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/EP1992/000841
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German (de)
English (en)
Inventor
Andreas MÜLLER
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.)
Daimler Benz AG
Original Assignee
Daimler Benz AG
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 Daimler Benz AG filed Critical Daimler Benz AG
Priority to CA002109211A priority Critical patent/CA2109211A1/fr
Priority to AU16430/92A priority patent/AU652052B2/en
Priority to EP92908599A priority patent/EP0589895A1/fr
Priority to JP4507989A priority patent/JPH06507053A/ja
Priority to FI934830A priority patent/FI934830L/fi
Publication of WO1992020179A1 publication Critical patent/WO1992020179A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure

Definitions

  • the invention relates to a digital modulation method and an arrangement for a multichannel transmission system, in which the data stream is divided into a number of subcarriers which lie next to one another in the frequency range.
  • the invention finds i.a. Use in the COFDM (Coded Orthogonal Freguency Division Multiplexing) method used in digital broadcasting.
  • COFDM Coded Orthogonal Freguency Division Multiplexing
  • the data stream to be transmitted is divided into a number (for example several 100) subcarriers, which lie next to one another in the frequency range, the spectra of the subcarriers also being able to overlap.
  • This procedure means that an order of magnitude lower than the original data rate is transmitted in each subcarrier, which increases the symbol duration accordingly. This has an advantageous effect if echoes occur on the transmission channel.
  • a multi-channel modulation method can always be designed in such a way that the symbol duration is large compared to the maximum echo delay to be expected.
  • the echo influence can e.g. switch off completely in that the symbols are not sent in direct succession, but rather that a protection time is provided between two successive symbols in which the echoes of the symbol sent first decay.
  • a multi-channel modulation method is e.g. as a digital method, for example as a program on at least one microprocessor with which the transmission signal in the complex baseband is calculated on the transmitter side or on an intermediate frequency. With known analog technology methods, this can then be placed in the carrier frequency position. Accordingly, the signal is first received in an analog manner in the receiver, then reduced to baseband or to an intermediate frequency and then further processed digitally.
  • the multi-channel modulation signal consists of time-frequency slots.
  • the time slots are determined by the discrete symbol clock, the frequency slots by the subcarrier Frequency spacing formed. If measures for combating echoes, for example the protection time mentioned above, are provided, the influence of the radio channel in each time-frequency slot consists in an attenuation and phase shift. Attenuation and phase shift are generally variable in time and frequency.
  • the known phase modulation is preferably used as the modulation method for a subcarrier of the multichannel signal.
  • the different data symbols are mapped onto different phase profiles of the transmission signal.
  • the channel-related phase shift then has an effect as a disturbance variable, which must be compensated for by suitable measures.
  • differential demodulation and differential precoding are differential demodulation and differential precoding.
  • the data are not transmitted in the phase of a symbol but in the phase difference of two successive symbols.
  • the differential demodulation and precoding are carried out separately in each subcarrier.
  • the differential precoding takes place in the transmitter (FIG. 1 a) and the differential demodulation takes place in the receiver (FIG. 1 b).
  • the multiplication of complex numbers corresponds to an addition of their phases, the formation of the conjugate complex number of the inversion of the sign of the phase.
  • the differential demodulation or precoding is based on the assumption that the channel-related phase rotation does not change from one symbol to the next. However, this assumption is often not met in the case of time-varying radio channels, particularly in the case of multi-channel methods with their relatively long symbol duration. Then transmission errors occur even in the noise-free state.
  • the invention is therefore based on the object
  • parts of a transmission-side and a reception-side arrangement are shown with a plurality of subcarriers ... k-1, k, k + 1 ..., each of which contains a multiplier on the transmitter side and the receiver side , which links the data of neighboring subcarriers.
  • the multiplied data of the subcarriers k-1, k are fed to the multiplier of the subcarrier k + 1 and multiplied by the data of the subcarrier k + 1.
  • this signal of subcarrier k + 1 is multiplied by the conjugate complex signal of subcarrier k.
  • This method is referred to as frequency differential modulation.
  • the method implemented with this arrangement is based on the assumption that the channel-related phase rotation does not change from one subcarrier to the next. This assumption is similar to that in the known differential modulation, only that the frequency invariance is substituted for the time invariance. Especially in the case of multichannel modulation methods, however, the latter is often more likely because the long symbol duration corresponds to a small frequency spacing of the subcarriers.
  • an arrangement on the transmitting and receiving side is specified, in which both data symbols of a subcarrier, which are consecutive in time, and data of neighboring subcarriers are linked to one another.
  • data which are transmitted in phase difference between two successive data symbols are given to a multiplier by the multiplied data of the subcarriers k-1, k.
  • This multiplied, complex signal of the subcarrier k + 1 is multiplied in the receiver by the conjugate complex signal of the subcarrier k. Then this multiplied signal with the conjugate complex, time-delayed signal is given to another multiplier.
  • the signals of the subcarriers are precoded differentially first and then frequency differential in the transmitter and then in the Receiver first demodulated differentially and then frequency differentially.
  • the double differential modulation can also be carried out first on the transmitter and receiver side by means of a frequency differential and a subsequent differential modulation.
  • double differential modulation has the decisive advantage that it does not require the assumption of a temporal invariance or a frequency invariance of the channel-related phase rotation, but rather the channel phase curve over time and frequency by a Approximate level. In radio channels, this approximation is significantly better than the approximation due to a phase curve that is constant over time and frequency.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radio Transmission System (AREA)
  • Transmitters (AREA)

Abstract

La présente invention se rapporte à un procédé de molulation numérique et à un agencement pour un système de transmission à canaux multiples dans lequel le flux de données est répartie sur plusieurs sous-porteuses juxtaposées dans la gamme de fréquences. Des sous-porteuses voisines sont reliées entre elles de telle manière que les données de deux sous-porteuses voisines sont transmises en différence de phase. Si l'on relie une telle modulation différentielle en fréquence à une modulation différentielle usuelle, dans laquelle des symboles de données successifs d'une sous-porteuse sont transmis en différence de phase, on obtient une qualité de transmission nettement meilleure des signaux dans les canaux radio.
PCT/EP1992/000841 1991-05-02 1992-04-14 Procede et agencement pour la modulation differentielle de signaux dans un systeme de transmission a canaux multiples Ceased WO1992020179A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CA002109211A CA2109211A1 (fr) 1991-05-02 1992-04-14 Methode et dispositif de modulation differentielle de signaux dans un systeme de transmission multicanal
AU16430/92A AU652052B2 (en) 1991-05-02 1992-04-14 Process and arrangement for the differential modulation of signals in a multi-channel transmission system
EP92908599A EP0589895A1 (fr) 1991-05-02 1992-04-14 Procede et agencement pour la modulation differentielle de signaux dans un systeme de transmission a canaux multiples
JP4507989A JPH06507053A (ja) 1991-05-02 1992-04-14 多チャネル伝送システムにおける信号の差分変調方法および装置
FI934830A FI934830L (fi) 1991-05-02 1992-09-14 Foerfarande och anordning foer differentiell modulation av signaler i ett flerkanals-oeverfoeringssystem

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4114274A DE4114274A1 (de) 1991-05-02 1991-05-02 Verfahren und anordnung zur differentiellen modulation von signalen in einem mehrkanal-uebertragungssystem
DEP4114274.8 1991-05-02

Publications (1)

Publication Number Publication Date
WO1992020179A1 true WO1992020179A1 (fr) 1992-11-12

Family

ID=6430783

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1992/000841 Ceased WO1992020179A1 (fr) 1991-05-02 1992-04-14 Procede et agencement pour la modulation differentielle de signaux dans un systeme de transmission a canaux multiples

Country Status (7)

Country Link
EP (1) EP0589895A1 (fr)
JP (1) JPH06507053A (fr)
AU (1) AU652052B2 (fr)
CA (1) CA2109211A1 (fr)
DE (1) DE4114274A1 (fr)
FI (1) FI934830L (fr)
WO (1) WO1992020179A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998012880A3 (fr) * 1996-09-20 1998-08-13 Siemens Ag Systeme de transmission numerique de donnees, procede et dispositifs appropries
EP0877504A1 (fr) * 1997-05-10 1998-11-11 Robert Bosch Gmbh Procédé de transmission de données, transmetteur et récepteur
GB2373148A (en) * 2001-02-01 2002-09-11 Roke Manor Research Intra symbol differential modulation of a multi-carrier signal
EP0787412A4 (fr) * 1994-10-21 2002-09-18 Seiko Comm Holding N V Transmission de donnees numeriques a l'aide de sous-porteuses multiples
GB2383726A (en) * 2001-12-31 2003-07-02 Calum Ian Bruce Gorton Dual frequency radian differential information transfer

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7239666B1 (en) 1994-09-09 2007-07-03 Sony Corporation Communication system
JP3577754B2 (ja) * 1994-09-09 2004-10-13 ソニー株式会社 通信方法及び装置
FI99252C (fi) * 1995-07-03 1997-12-29 Nokia Mobile Phones Ltd Yhdistetty radiosignaalin modulointi- ja monikäyttömenetelmä
EP0991237A1 (fr) * 1998-09-30 2000-04-05 TELEFONAKTIEBOLAGET L M ERICSSON (publ) Procédé de communication multiporteuse avec codage différentiel espace-temps
US8361045B2 (en) † 2006-03-10 2013-01-29 Kimberly-Clark Worldwide, Inc. Apparatus and method for manufacturing several distinct disposable absorbent articles on a single machine

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4029478C2 (de) * 1989-09-28 1995-08-03 Siemens Ag Verfahren zur Übertragung von Daten in einem Bussystem
DE3935911A1 (de) * 1989-10-27 1991-05-02 Deutsche Forsch Luft Raumfahrt Verfahren zur empfangsseitigen bitdetektion von differentiell codierten binaeren oder quaternaeren psk-signalen bei differentiellkohaerenter demodulation

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
IEEE International Conference on Communications, 11-14 Juni, 1989, Boston, US; IEEE, New York, US, 1989; Seiten 275 - 280, Makrakis: "A novel fading cancellation scheme for trellis coded ø systems based on a multichannel approach" *
PHILIPS RESEARCH REPORTS + SUPPLEMENTS. Nr. 4, 1973, EINDHOVEN NL Seiten 91 - 98; SCH]ELI: 'Schnelle Parallel - Daten}bertragung mit zeitbegrenzten Impulsen' *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0787412A4 (fr) * 1994-10-21 2002-09-18 Seiko Comm Holding N V Transmission de donnees numeriques a l'aide de sous-porteuses multiples
WO1998012880A3 (fr) * 1996-09-20 1998-08-13 Siemens Ag Systeme de transmission numerique de donnees, procede et dispositifs appropries
EP0877504A1 (fr) * 1997-05-10 1998-11-11 Robert Bosch Gmbh Procédé de transmission de données, transmetteur et récepteur
GB2373148A (en) * 2001-02-01 2002-09-11 Roke Manor Research Intra symbol differential modulation of a multi-carrier signal
GB2383726A (en) * 2001-12-31 2003-07-02 Calum Ian Bruce Gorton Dual frequency radian differential information transfer

Also Published As

Publication number Publication date
JPH06507053A (ja) 1994-08-04
CA2109211A1 (fr) 1992-11-03
FI934830A7 (fi) 1993-11-01
EP0589895A1 (fr) 1994-04-06
FI934830A0 (fi) 1993-11-01
AU1643092A (en) 1992-12-21
AU652052B2 (en) 1994-08-11
FI934830L (fi) 1993-11-01
DE4114274A1 (de) 1992-11-05

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