EP2097987A1 - Système pour une communication sans fil - Google Patents

Système pour une communication sans fil

Info

Publication number
EP2097987A1
EP2097987A1 EP06819923A EP06819923A EP2097987A1 EP 2097987 A1 EP2097987 A1 EP 2097987A1 EP 06819923 A EP06819923 A EP 06819923A EP 06819923 A EP06819923 A EP 06819923A EP 2097987 A1 EP2097987 A1 EP 2097987A1
Authority
EP
European Patent Office
Prior art keywords
modulation
frequency
signal
transmission
band
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.)
Withdrawn
Application number
EP06819923A
Other languages
German (de)
English (en)
Inventor
Wolfgang Konrad
Janos Gila
Peter Veith
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.)
Siemens AG Oesterreich
Original Assignee
Siemens AG Oesterreich
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 Siemens AG Oesterreich filed Critical Siemens AG Oesterreich
Publication of EP2097987A1 publication Critical patent/EP2097987A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/30—Circuits for homodyne or synchrodyne receivers
    • H04B1/302—Circuits for homodyne or synchrodyne receivers for single sideband receivers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D3/00—Demodulation of angle-, frequency- or phase- modulated oscillations
    • H03D3/001—Details of arrangements applicable to more than one type of frequency demodulator
    • H03D3/002—Modifications of demodulators to reduce interference by undesired signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/12—Frequency diversity

Definitions

  • the invention relates to a system for wireless communication with a transmitting unit and at least one receiving unit.
  • frequency diversity method improves the transmission reliability by transmitting the same information at different frequencies simultaneously, exploiting the effect that different frequency ranges offer different transmission characteristics and interference signals usually do not affect all frequencies used choose the frequency that gives the most favorable reception situation at its location.
  • this "frequency diversity method" is very expensive since the transmitter according to the prior art must contain a plurality of complete transmission devices corresponding to the number of different frequencies used can be used to determine the optimal frequency.
  • modulation An important term in wireless communication is the so-called modulation. This is understood to mean the imposition of information on a carrier signal, which may for example also be a DC signal with the frequency 0. In this case we are talking about baseband modulation. Frequently, however, the modulation is used to put the modulated signal in a different frequency band, and adapt the transmission characteristics to special requirements. In this case we are talking about a bandpass modulation.
  • the information is transmitted by the carrier properties, such as amplitude and / or phase. Thus, others, especially higher
  • Frequency ranges for wireless transmission available are known.
  • modulation methods for example the frequency modulation, the phase modulation, the amplitude modulation and many, for each own applications advantageous, further method.
  • Amplitude modulation is one of the simplest and most commonly used modulation techniques.
  • An amplitude-modulated signal is produced by multiplying the useful signal by a, generally substantially higher-frequency, carrier signal.
  • the final carrier frequency position is achieved by an intermediate step, in which case the modulation is first impressed on an intermediate frequency with fixed frequency and converted in a next step in the final frequency position.
  • the spectrum of an amplitude-modulated signal consists of the carrier signal and the two so-called sidebands, which both contain identical information content, that of the useful signal. If the modulation is first impressed on an intermediate frequency carrier, two frequency bands are formed around this intermediate frequency carrier, the upper and lower sideband. By further multiplication with a local oscillator signal - a so-called êtstrager - the final transmission signal is obtained.
  • the mirror band is usually suppressed in practical applications because it contains the same information as the modulation spectrum and, moreover, in many applications leaves the frequency range prescribed by regulations. In order to suppress the unwanted mirror band, expensive circuits such as filters or I / Q modulators in the transmitter unit are required.
  • the invention has for its object to provide a system by which a communication of a
  • Sending unit can take place with one or more receiving units and the transmission reliability is increased.
  • the object is solved according to the invention with a system for wireless communication with a transmitting unit and at least one receiving unit, in which the transmitting unit emits a modulated signal at a carrier frequency, which also contains its mirror band in addition to a modulation spectrum, and the receiving unit contains means for selecting or demodulating either the modulation spectrum or its mirror band as a function of predetermined criteria.
  • the characteristics of a 2 frequency diversity transmission can be achieved with very little effort.
  • This low cost of components also leads to a high reliability, lower space requirements and lower power consumption.
  • the signal emitted by the transmitting unit contains the respective image frequencies in addition to the two side bands, it is possible, for example, to omit the filters or I / Q modulators provided in conventional transmitting circuits. In addition to these cost and complexity reduction effects, the information is simultaneously transmitted in two frequency bands and thus an inherent frequency diversity is realized.
  • a further advantageous feature of the solution is that the carrier signal is suppressed and thus the entire transmitted power is conducted into the side band containing the information and its mirror band.
  • reception quality of the demodulated signal is provided as a predetermined criterion for the selection of one of the side bands. This can be the Transmission reliability can be increased to a particular extent.
  • This error rate can be easily determined and provides a reliable statement about the property of the transmission channel.
  • Modulation method is kept low.
  • the application of a binary FSK method with a large stroke leads to realization advantages for receiving units.
  • Fig. 1 shows the typical spectrum of a signal in
  • Fig. 2 is a functional diagram of a transmitting unit according to the invention
  • Fig. 3 is a block diagram of a system according to the invention.
  • Fig. 4 is a functional diagram of an inventive
  • FIG. 5 shows a functional diagram of an embodiment of a transmitting unit
  • FIG. 1 shows a spectrum of a signal which consists of an intermediate frequency carrier signal Ft and the two associated sidebands USB and OSB. Such a signal is typical for double sideband modulation.
  • the horizontal axis represents the frequency f, the vertical axis the signal level Sig.
  • FIG. 2 shows a functional block diagram of a transmitting unit S and the respectively generated spectra, wherein according to the invention the modulation spectrum MS and its mirror band SB are transmitted.
  • a modulation frequency Fmod is by means of a first modulation stage Ml to a
  • the resulting spectrum Sigl corresponds to the spectrum shown in FIG.
  • the applied multiplication suppresses the transmission carrier FIo.
  • the figure also includes negative spectral components, which merely form a statement that the applied
  • Modulation method generates a real signal.
  • the signal Sig2 applied to the output of the second modulation stage M2
  • FIG. 3 shows, by way of example and schematically, a block diagram of a conversion according to the invention.
  • the transmitting unit S transmits a signal Sig2 with the spectrum shown in FIG. 2, which is received by a receiving unit E.
  • This receiving unit E demodulates the received signal Sig2 and makes it available to an evaluation decision unit AE.
  • This evaluation decision unit AE determines the reception quality on the basis of criteria from the received signal Sig2 and switches the reception unit E to the reception of the modulation band MS or its mirror band SB by means of a frequency selection FA.
  • This can be achieved, for example, by selecting the frequency selection FA between two, on the Mirror band frequencies tuned, generated by quartz frequencies, which are provided to the receiver E as an intermediate frequency.
  • the frequency selector FA can drive, for example, a PLL (Phase Locked Loop) in order to generate the two required frequencies.
  • PLL Phase Locked Loop
  • the evaluation decision unit AE switches back to the originally used band. This ensures that the band offering the most favorable transmission conditions is selected.
  • the reception level of the modulation spectrum MS or its mirror band SB can be determined in order to derive therefrom the criterion for switching to the respective other band.
  • signal quality measures such as e.g. To determine and evaluate bit error rate or packet error rate. These signal quality measures are used as the basis for selecting either the modulation spectrum MS or its mirror band SB.
  • FIG. 4 shows a functional diagram of an exemplary receiving unit E, the receiving signal being alternative demodulated either by means of a first demodulation frequency Flol or a second demodulation frequency Flo2.
  • the selection of the demodulation frequency to be used is made by the evaluation decision unit AE, which makes this selection depending on certain criteria.
  • FIG. 5 shows a functional diagram of a favorable embodiment of a transmitting unit S with which a frequency shift keying method is implemented.
  • 2 frequency generators such as quartz oscillators QOl, QO2 or ceramic oscillators, etc. which each have slightly different, adapted to the desired spectrum of the transmitted signal frequencies are of, in this case digital modulation signal Fmod respectively alternatively, via a signal former SF and a frequency divider FT, on the modulated in this case also digital transmitter signal.
  • the divider and / or the signal conditioning stage can be omitted.
  • the XOR gate X can also be replaced by a multiplier.

Landscapes

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

Abstract

La présente invention concerne un système pour une communication sans fil avec une unité émettrice et au moins une unité réceptrice, caractérisé en ce que l'unité émettrice S émet à une fréquence porteuse de transmission Flo un signal modulé qui contient outre un spectre de modulation MS, également sa bande image SB, et en ce que l'unité réceptrice contient des moyens AE pour sélectionner ou démoduler en fonction de critères prédéfinis soit le spectre de modulation MS soit sa bande image SB. Ainsi, on peut obtenir l'avantage que la sécurité de transmission peut être sensiblement augmentée par rapport au cas où seulement un spectre de modulation est transmis, étant donné que des influences perturbatrices sur le chemin de transmission entre l'unité émettrice et l'unité réceptrice ne concernent que rarement aussi bien les plages de fréquences du spectre de modulation que sa bande image.
EP06819923A 2006-12-07 2006-12-07 Système pour une communication sans fil Withdrawn EP2097987A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2006/069434 WO2008067851A1 (fr) 2006-12-07 2006-12-07 Système pour une communication sans fil

Publications (1)

Publication Number Publication Date
EP2097987A1 true EP2097987A1 (fr) 2009-09-09

Family

ID=38357989

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06819923A Withdrawn EP2097987A1 (fr) 2006-12-07 2006-12-07 Système pour une communication sans fil

Country Status (3)

Country Link
EP (1) EP2097987A1 (fr)
CN (1) CN101584122A (fr)
WO (1) WO2008067851A1 (fr)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5008939A (en) * 1989-07-28 1991-04-16 Bose Corporation AM noise reducing
EP1164533B1 (fr) * 2000-06-12 2006-09-20 Supersensor (Proprietary) Limited Lecteur pour des bandes différentes latérales d'un système d'identification électronique
GB2397973A (en) * 2003-01-30 2004-08-04 Radiodetection Ltd Comparing sideband signal quality metrics

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2008067851A1 *

Also Published As

Publication number Publication date
WO2008067851A1 (fr) 2008-06-12
CN101584122A (zh) 2009-11-18

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