EP0571366A1 - Dispositif pour la transmission d'informations entre plusieurs stations d'abonnes d'un reseau de communication local - Google Patents

Dispositif pour la transmission d'informations entre plusieurs stations d'abonnes d'un reseau de communication local

Info

Publication number
EP0571366A1
EP0571366A1 EP19900916272 EP90916272A EP0571366A1 EP 0571366 A1 EP0571366 A1 EP 0571366A1 EP 19900916272 EP19900916272 EP 19900916272 EP 90916272 A EP90916272 A EP 90916272A EP 0571366 A1 EP0571366 A1 EP 0571366A1
Authority
EP
European Patent Office
Prior art keywords
pulse
radiation
stations
station
transmission
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Withdrawn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
EP19900916272
Other languages
German (de)
English (en)
Inventor
Wolfgang Kemmler
Amer Amin
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.)
Wincor Nixdorf International GmbH
Original Assignee
Wincor Nixdorf International GmbH
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 Wincor Nixdorf International GmbH filed Critical Wincor Nixdorf International GmbH
Publication of EP0571366A1 publication Critical patent/EP0571366A1/fr
Withdrawn legal-status Critical Current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
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • H04B10/114—Indoor or close-range type systems
    • H04B10/1149—Arrangements for indoor wireless networking of information

Definitions

  • the invention relates to a system for transmitting data in half duplex mode between a plurality of subscriber stations of a local communication network via at least two intermediate stations, the data being transmitted between a subscriber station and an intermediate station in each case by means of modulated radiation in the room.
  • Such a system which is used for data transmission for a local network in the field of computer-aided manufacturing (CIM) is known from an article "Data transmission with infrared light" in the specialist journal Electronics 24 / 25.11.1988, pages 82 to 90 .
  • Several intermediate stations establish the wireless connection by means of an infrared transmission link to subscriber stations of a flexible transport system in a spacious factory hall.
  • the intermediate stations are connected to each other via lines and connected to a master computer that controls data traffic.
  • the data transmission takes place in half-duplex operation, in which a subscriber station either sends or receives data, however, simultaneous data traffic in both directions is not intended.
  • the intermediate stations usually mounted on the ceiling of the room have to be connected to one another by a permanently installed data line network. If such a system is expanded to a larger hall area or if the transmission system is modified, in which the subscriber stations are assigned new locations, complex installation work for the line network is required.
  • This object is achieved for a system of the type mentioned at the outset in that the data transmission between the intermediate stations of the same structure is also carried out by radiation, in that the radiation for transmitting binary data is subjected to pulse modulation in that the intermediate stations each arrive transmit a pulse in response to a pulse, and that the readiness to receive is at least for a time T after the arrival of a pulse, which is equal to the sum of twice the pulse transit time between the transmitting station and the most distant receiving station within the transmission range and the pulse duration .
  • pulse modulation is used for data transmission.
  • the pause following a pulse is varied depending on the binary value of the data to be transmitted.
  • a long pause is assigned to the binary value 1, and a short pause to the value 0.
  • the pulse duration itself, ie the The time in which radiation is emitted is such that the intermediate stations switched to receive and the subscriber stations can safely receive the pulse.
  • This type of modulation means that the radiation energy required for data transmission is minimal, since the information is essentially contained in the length of the pause.
  • the pulse amplitude can be high for a predetermined amount of radiation energy, so that a large transmission range and a high signal-to-noise ratio with respect to the ambient radiation are achieved.
  • pulse modulation can also be used.
  • a modulation with a fixed time pattern can be carried out, in which the binary information is encrypted in successive predetermined time segments of constant length. This can be done in such a way that the emission of a radiation pulse is interpreted as binary value 1 within a time period. The absence of such a pulse is then interpreted as a binary value 0.
  • the pulse which is generally emitted in all directions, loses intensity as a result of the divergence of the radiation and as a result of scattering and absorption in air and on particles along its path of propagation. Accordingly, a transmission range can be defined for the respective subscriber station or intermediate station, which indicates the distance at which a sufficiently good reception signal is still present.
  • the decisive factor here is compliance with a predefined signal-to-noise ratio to interference signals such as, for example, noise, background radiation and interference radiation.
  • the pulse received by an intermediate station within the range of a transmitting station triggers the transmission of a new pulse, which in turn is received by intermediate stations within its range.
  • the intermediate stations constructed in the same way generally send their pulses in all directions and can also receive pulses from all directions. This means that after the transmission of a pulse, the intermediate stations receive pulses again from intermediate stations adjacent to them. Without further measures, these impulses would cause new impulses to be sent which are not related to the data to be transmitted and thus interfere with the transmission.
  • the invention provides that the readiness for reception of a transmitting station is at a standstill T. During this time, incoming impulses cannot trigger new impulses.
  • the time T is at least the sum of twice the pulse transit time between the sending station and the most distant receiving station within the transmission range and the pulse duration.
  • This measure also ensures that the crosstalk from the sending station or impulses generated by reflection on obstacles in the transmission path are suppressed and consequently no erroneous impulses are received and transmitted again.
  • the readiness for reception of the subscriber stations also rests for the time T, so that their data reception is not disturbed by returning pulses.
  • the data transmission between the intermediate stations is carried out by radiation, the installation of a line network for the intermediate stations is not necessary.
  • the spatial expansion of an existing data transmission system can therefore be carried out without great technical outlay, since further intermediate stations can be arranged in the room in a simple manner.
  • the system according to the invention does not require a central control for the data traffic, as is the case with the prior art, since the data transmission can take place asynchronously and the intermediate stations work independently of one another without interfering with one another.
  • the intermediate stations themselves are very simple, since they do not have to perform any storage function or signal processing function. They can be implemented using simple electronic means.
  • the system according to the invention allows a high transmission speed and data transmission rate, since the transmission of the data from a sending to a receiving subscriber station takes place almost at the speed of light.
  • the pulse repetition frequency for the transmission is also influenced by the time T during which the stations are ready to receive.
  • time T is also determined by the pulse transit time between the stations, which in turn depends on the speed of light in air and the transmission range. The latter can be optimized so that the time T becomes minimal. If pulses with a short pulse duration are used, a high pulse repetition frequency and thus a high data transmission rate can be achieved.
  • Both visible light and infrared radiation can be used as radiation.
  • the latter has the advantage that with the aid of simpler electronic components, such as light-emitting diodes, a high radiation intensity and thus a long transmission range are achieved in pulse mode.
  • electromagnetic radiation in the radio frequency range or in the micelle range can also be used as radiation.
  • a preferred embodiment of the invention is characterized in that when the pulse is sent out delayed by a reaction time, the time T is additionally extended by at least this reaction time.
  • the response time is due to the switching time and the delay of inductive and capacitive components of the electronic components in the intermediate stations. Since the unfavorable timing behavior of such components can be compensated for with the aid of the measures mentioned, it is possible to use very simple and inexpensive electronic components with long switching times when implementing the intermediate stations in terms of circuitry.
  • the intermediate stations are arranged at equal distances from one another.
  • the intermediate stations then form a connection network composed of equilateral triangles, at the corners of which an intermediate station is arranged.
  • This arrangement ensures that each intermediate station, with the exception of those which are arranged at the edge of the network, is surrounded by six directly adjacent intermediate stations. If one or even more of these stations fails, it is still guaranteed that the pulse emitted by a remaining neighboring station can still be received and further pulse transmission is thus ensured. This means that the system still works very reliably even if individual intermediate stations fail.
  • this arrangement achieves a high and uniform density of intermediate stations in the room, so that data transmission from one subscriber station to another can take place reliably regardless of the location of the subscriber stations in the room.
  • a further development of the described embodiment provides that the distances are equal to the transmission range. This measure minimizes the number of intermediate stations required and reduces the technical complexity of the system.
  • FIG. 1 a shows a sequence of pulses after pulse modulation with variable pulse pauses
  • Fig. Lb a sequence of pulses with a fixed time pattern
  • 2 shows an arrangement with two subscriber stations and two intermediate stations
  • 3 shows a schematic structure of the electronic components of an intermediate station in a block representation
  • Fig. 7 pulse diagrams over time for three intermediate stations, which are within a transmission range
  • FIG. 1 a shows pulse sequences over time t for the pulse modulation used to transmit binary data.
  • Radiation pulses with the pulse height H and the duration tp are emitted over time t with different pauses to, tl.
  • a short pause tO corresponds to the binary value 0
  • a long pause tl is the binary value 1.
  • the pulse duration tp should be as short as possible so that the radiated radiation energy • is low or the pulse height H is large for a given radiation energy.
  • This pulse height H essentially determines the transmission range and the signal-to-noise ratio to interference signals.
  • Fig. 1b Another possible type of pulse modulation is shown in Fig. 1b.
  • the duration tp of the pulse may not exceed the length t2 of the time segment.
  • the pulse duration tp is preferably chosen to be considerably smaller than the length t2 in order to obtain a large pulse height H for a predetermined pulse energy.
  • the subscriber stations 10, 12 can be, for example, computer terminals, personal computers with a communication interface, work stations for computer-aided production or automatic cash register stations and are located near the floor of the room.
  • the subscriber stations 10, 12 are mobile, i.e. depending on the application, they can be located in different places in the room.
  • the subscriber stations 10, 12 each have one
  • Transmitter-receiver unit 14 or 16 each with a structure corresponding to an intermediate station have, which is described in more detail.
  • the transmitter-receiver units 14, 16 have a spherical directional characteristic 15 for the radiation to be received and emitted and are aligned with the intermediate stations 18 and 20 adjacent to them. This improves the interference immunity of the transmission link between the intermediate station 18 or 20 and the respective subscriber station 10, 12.
  • the data traffic between the subscriber stations 10, 12 is processed after the half-duplex operation. This means that the subscriber stations 10, 12 alternately send and receive data.
  • one of the transmitter / receiver units 14, 16 is activated, which transmits data in the form of modulated radiation pulses which are forwarded in space by the intermediate stations 18, 20. All subscriber stations 10, 12 of the room receive these pulses via their respective transmitter-receiver units 14, 16. The pulses are then evaluated in the respective subscriber stations 10, 12 according to known methods and the corresponding data are further processed.
  • the 'intermediate stations 18, 20 are arranged on the ceiling 24 of the room at a distance from each other, at least the transmission range of the intermediate stations 18, corresponding to the 20th Infrared radiation with a wavelength of approximately 1 micron typical for semiconductor radiation sources is used as radiation.
  • the receiving elements of the intermediate stations 18, 20 and the transceiver units 14, 16 are provided with filters (not shown), the wavelength range of which is matched to the radiation from the semiconductor radiation sources is.
  • the intermediate stations 18, 20 are each supplied with power from a power supply unit (not shown).
  • a receiving module 26 equipped with a photodiode detects a pulse 25 which has been emitted by an intermediate station or a transceiver unit of a subscriber station and converts this into an electrical signal. This is fed via a switch arrangement 28 to a preamplifier 30, the impedance of which is matched to the receive module 26 for as low-noise amplification as possible.
  • the output signal of the amplifier 30 is fed to a threshold switch 32, which compares it with a predetermined threshold value 31. If the output signal exceeds this threshold value 31, the threshold value switch outputs a signal 33 by means of which the presence of a valid pulse 25 can be determined.
  • the signal 33 can then be used in a transceiver unit 14, 16 for evaluating the binary information in a subscriber station.
  • the signal 33 is also fed to a pulse shaping stage 36, which generates a control pulse with the pulse duration tp and thus controls a diode array 38.
  • the diode array 38 consists of a plurality of light emitting diodes (LED) which emit infrared radiation with a wavelength of approximately 1 micrometer.
  • the diodes operate in so-called pulse mode, ie their pulse pause is considerably longer than the time in which they emit radiation. This makes it possible to apply high pulse currents to the diodes, which generate a high radiation intensity. By using several diodes, the total radiated power is enlarged and by different alignment of the diodes, the radiation can be emitted in a large solid angle.
  • the output signal 33 of the threshold switch 32 is also fed to a timing element 34, which opens the switching path of the switch arrangement 28 for a predetermined time T. During this time T, pulses 25 detected by the receiving module 26 are not forwarded to the preamplifier 30, so that the threshold switch 32 does not emit a signal 33 which signals a valid pulse.
  • FIG. 4 shows test results in a diagram for determining the transmission range.
  • the critical value of 0.5 V is used as the threshold value 31 in the comparison in the threshold value switch 32.
  • FIG. 5 shows pulse diagrams over time t, which show the transmission of pulses between two Intermediate stations 42, 44 lying within the transmission range R.
  • the pulse 48 arrives with a time delay ti which corresponds to the duration of the radiation Air to station 44 corresponds to station 44.
  • tr which is due to switching times of the electronic components of the intermediate station 44
  • the station 44 sends out a pulse 50 in all directions.
  • the pulse 50 subsequently arriving at the previously sending station 42 will be considered in more detail below. It arrives at station 42 after the pulse transit time ti and would trigger another pulse there without further countermeasures. In the further course, this would lead to the stations 42, 44 continuously exchanging pulses at the time interval ti.
  • the transmission of binary information would not be possible.
  • the readiness for reception of the station 42 is stopped for a time T when its pulse 48 is transmitted, so that pulses arriving during this time T cannot trigger any further pulses.
  • this time T must satisfy the relationship T ti + tr + ti + tp. Only then is it ensured that the station 42 does not emit any disturbing follow-up pulses.
  • the pulse 50 sent out by the station 44 is received by the station 46 and triggers a subsequent pulse there. Its intensity is too low to be recognized as a valid pulse at station 42.
  • 6 shows in five representations a) to e) the transmission of data between a plurality of subscriber stations 52 to 58 of a local communication network. The subscriber stations 52 to 58 are identified by a triangle.
  • a large number of intermediate stations identified by circles are provided for data transmission and form a transmission network.
  • the intermediate stations are arranged at equal distances from one another, as indicated by the dashed circle 60 in illustration a).
  • the distances between the intermediate stations are equal to the transmission range R.
  • the subscriber station 52 sends out a pulse which the intermediate station closest to it receives. This then sends out a subsequent pulse which, according to illustration c), is received by two neighboring intermediate stations.
  • the simultaneous reception of these impulses is marked by a connecting line.
  • This connecting line can be understood as a wave front of propagating impulses.
  • this wavefront has advanced by further intermediate stations and in the illustration e) reaches the subscriber station 54 which is furthest away from the subscriber station 52.
  • the pulses from the sending subscriber station 52 must therefore be passed on via eight intermediate stations.
  • the subscriber stations 56 and 58 receive the transmitted data after the impulses have been forwarded five times through intermediate stations.
  • FIG. 7 shows further pulse diagrams over time t, which provide information about the time "T" required for a station to be ready to receive give if there are several stations in the transmission range R with different distances from the transmitting station.
  • a station 60 which may be an intermediate station or a subscriber station, transmits a pulse 66 which is well received by both a station 62 and a station 64 further away.
  • the pulse 66 requires the transit time ti, as does the pulse 68 sent back by the station 62.
  • the response time tr has been set to zero for a better understanding of the relationships described below.
  • the pulse 66 requires the transit time ti 'until it arrives at the further distant station 64.
  • the pulse 70 sent back from station 64 to station 60 has the same transit time ti '.
  • T For interference-free data transmission, as can be seen from FIG. 7, it is necessary for station 60 to be ready for reception at least the time T, which results from the relationship T> ti '+ ti' + tp.
  • the reaction time tr has to be added, which has been neglected in this example. It should therefore be noted that the time T is essentially determined by the pulse transit time ti 'between the transmitting station 60 and the receiving station 64, which is the most distant within the transmission range.
  • FIG. 8a shows an exemplary embodiment of an intermediate station 72, the emitted radiation of which has a rotationally symmetrical directional characteristic with a spherical main lobe 74 and two secondary lobes 76, 78.
  • the intermediate station 72 is fastened below the ceiling 24 of the room.
  • the Main lobe 74 has an axis 86 which runs parallel to the surface normal of the ceiling 24.
  • subscriber stations which are usually located near the bottom of the surface.
  • the side lobes 76, 78 have axes 82, 80 which run parallel to the ceiling 24.
  • Adjacent intermediate stations are located in the direction of these axes 82, 80. This directional characteristic ensures that the radiated energy is preferably radiated both in the direction of the subscriber stations and in the direction of the intermediate stations, so that on the one hand the energy consumption is minimized and on the other hand a large transmission range is achieved.
  • the intermediate station 72 has an approximately hemispherical directional characteristic 90, i.e. the radiation intensity radiated into the room - indicated by arrows 91 to 94 - is the same for all solid angles of the half-space.
  • a directional characteristic 90 can e.g. by arranging several radiation-emitting semiconductor components, such as LEDs or laser diodes, on a carrier. The components are aligned in such a way that the main axes of their radiation point in different directions and run along normal to the surface of a hemisphere, the central axis of which points towards the interior of the room. The resulting radiation intensity in space is then approximately constant for all solid angles.

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

Abstract

Dans un dispositif pour la transmission d'informations, en exploitation semi-duplex, entre plusieurs stations d'abonnés (10, 12) d'un réseau de communication local, la transmission des informations entre une station d'abonné (10 ou 12) et une station intermédiaire (18 ou 20) s'effectue par rayonnement modulé dans l'espace. Conformément à l'invention, la transmission des informations s'effectue également entre les stations intermédiaires (18, 20) par rayonnement. Celui-ci est soumis, pour la transmission d'informations binaires à une modulation par impulsions. Les stations intermédiaires (18, 20) émettent respectivement une impulsion à chaque arrivée d'une impulsion. La disponibilité de réception des stations (10, 12, 18, 20) est au repos après réception d'une impulsion, au moins pour un temps T qui est égal à la somme de la durée double de propagation de l'impulsion ti entre la station émettrice et la station réceptrice la plus éloignée dans le domaine de transmission R, et de la durée de l'impulsion tp. Le nouveau dispositif est remarquable par le fait qu'il présente une grande souplesse et qu'il peut être réalisé avec des moyens simples.
EP19900916272 1989-11-07 1990-10-31 Dispositif pour la transmission d'informations entre plusieurs stations d'abonnes d'un reseau de communication local Withdrawn EP0571366A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3937096 1989-11-07
DE19893937096 DE3937096A1 (de) 1989-11-07 1989-11-07 System zum uebertragen von daten zwischen mehreren teilnehmerstationen eines lokalen kommunikationsnetzes

Publications (1)

Publication Number Publication Date
EP0571366A1 true EP0571366A1 (fr) 1993-12-01

Family

ID=6393065

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900916272 Withdrawn EP0571366A1 (fr) 1989-11-07 1990-10-31 Dispositif pour la transmission d'informations entre plusieurs stations d'abonnes d'un reseau de communication local

Country Status (4)

Country Link
EP (1) EP0571366A1 (fr)
JP (1) JPH0793626B2 (fr)
DE (1) DE3937096A1 (fr)
WO (1) WO1991007028A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4026073A1 (de) * 1990-08-17 1992-02-20 Telefunken Systemtechnik Schnittstelle
DE4140306A1 (de) * 1991-12-06 1993-06-09 Guenther Dipl.-Kaufm. 2000 Hamburg De Beilicke Datenuebertragungseinrichtung
SE470518B (sv) * 1992-11-09 1994-06-27 Pricer Norden Ab Förfarande och anordning för kvittering av information
SE502430C2 (sv) * 1994-02-23 1995-10-16 Pricer Norden Ab Förfarande och anordning för kvittering av mottagandet av en information utsänd till en adresserad elektronisk prismärkningsetikett.
GB9412031D0 (en) * 1994-06-16 1994-08-03 Iml Ltd Improvements in signalling devices employing line of sight radiation
DE10116838C1 (de) * 2001-04-04 2002-11-28 Siemens Ag Verfahren zur Halbduplexübertragung von Informationen zwischen Kommunikationseinrichtungen mit Repeatern

Family Cites Families (6)

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Publication number Priority date Publication date Assignee Title
DE2554637A1 (de) * 1975-12-04 1977-06-08 Siemens Ag Verfahren zur fernsteuerung durch infrarotlicht-uebertragung
US4090067A (en) * 1976-11-02 1978-05-16 Sperry Rand Corporation Optical data communication system
DE3244712A1 (de) * 1982-12-03 1984-06-14 Standard Elektrik Lorenz Ag, 7000 Stuttgart Geraeteanordnung der unterhaltungs- und/oder gebaeudeelektronik mit einem drahtlosen uebertragungsweg zwischen einem gebergeraet und einem empfaengergeraet
DE3434742A1 (de) * 1984-09-21 1986-04-03 Siemens AG, 1000 Berlin und 8000 München Sende- und empfangsverfahren fuer relais-stationen
JPH01176127A (ja) * 1987-12-28 1989-07-12 Ncr Corp 光空間通信システム
JPH0724387B2 (ja) * 1988-01-11 1995-03-15 富士通株式会社 無線信号中継方法および装置

Non-Patent Citations (1)

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Title
See references of WO9107028A1 *

Also Published As

Publication number Publication date
WO1991007028A1 (fr) 1991-05-16
DE3937096C2 (fr) 1991-11-21
DE3937096A1 (de) 1991-05-08
JPH0793626B2 (ja) 1995-10-09
JPH04505083A (ja) 1992-09-03

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