EP0651361B1 - Alarm system with a radio link between the peripheral stations and a central unit - Google Patents
Alarm system with a radio link between the peripheral stations and a central unit Download PDFInfo
- Publication number
- EP0651361B1 EP0651361B1 EP94116871A EP94116871A EP0651361B1 EP 0651361 B1 EP0651361 B1 EP 0651361B1 EP 94116871 A EP94116871 A EP 94116871A EP 94116871 A EP94116871 A EP 94116871A EP 0651361 B1 EP0651361 B1 EP 0651361B1
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- Prior art keywords
- transmission
- alarm system
- frequencies
- external stations
- radio
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
- G08B25/003—Address allocation methods and details
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
- G08B25/007—Details of data content structure of message packets; data protocols
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
- G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
- G08B25/10—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using wireless transmission systems
Definitions
- the invention relates to a method for operating a radio alarm system a radio link mix the outstations and the central unit one Alarm system according to the preamble of claim 1.
- the field strength of the received signals of the signaling units is checked and a warning is triggered if a predetermined field strength value is exceeded for a certain period of time.
- the frequency hopping method is also known from message transmission. Such a method is given, for example, in German published application DE-A-34 15 032. According to this method, the messages or data which are transmitted by radio between two stations synchronized with one another are divided and transmitted in blocks. The carrier frequency is changed pseudorandomly at short intervals within a predetermined frequency band. A code generator is arranged in the transmitting and receiving devices of the radio stations, which generates a hopping scheme which characterizes the transmission device. To further increase the transmission security, the hopping frequencies are monitored for interference interference and the frequencies at which interference frequently occurs are no longer used for transmission.
- the frequency hopping process as it emerged from the Telecommunications is known, but is for use too complex in the area of security technology, because transmitters and the receiver must be synchronized.
- the transmission frequency on which the Outstations send their messages to the headquarters, after sending one or more blocks of information changed.
- Each block of information becomes multiple sent to ensure reception at headquarters.
- the available transmission spectrum is in the head office scanned. There is still an evaluation of whether all reported sensors within a given Time interval have sent a message and whether the Error rate of the messages submitted a predetermined Value does not exceed.
- the advantage of the radio alarm system according to the invention results from the repeated transmission of a Message using different transmission frequencies.
- a predefinable number of carrier frequencies on which the information blocks are transmitted is determined within the available transmission bandwidth.
- the period of time within which a carrier frequency is transmitted corresponds to the transmission period of an information block or a multiple thereof. In this way, one or more or all of the entire information blocks are transmitted on one frequency before switching to the next transmission frequency, and the transmitted information is not transmitted simultaneously over several frequencies.
- the Invention contain the individual transmitted Information blocks one synchronization block, one Useful information block and an error correction block.
- the error correction block in the Central unit an evaluation of the received Information regarding transmission errors.
- This Transmission errors can be at least partially corrected become.
- the errors can be targeted Fault can be closed. So this way you can the otherwise usual monitoring of radio alarm systems Reception field strength can be dispensed with.
- the error correction can be implemented by a processor that is used for Decoding of the received signals is required anyway.
- Another possibility is the parallel reception of several or all possible transmission frequencies, whereby the Transmission security of the radio alarm system is further increased becomes.
- Another advantageous embodiment of the invention stipulates that the sequence of the monitoring process for the possible transmission frequencies at random is set to provide even greater immunity to interference To achieve radio transmission.
- FIG. 1 shows the structure an information block (Figure 1a) and the division of the channel in the time and frequency domain ( Figure 1b).
- FIG. 1a shows an information block which consists of a first synchronization block Sync, a subsequent block with the useful information and a third block with a correction code.
- An information block for radio alarm systems that is emitted by the respective alarm transmitters can consist of less than 100 bits.
- the synchronization block Sync can consist of 24 bits
- the user information block can consist of 32 bits, for example 24 bits of the user information block being provided for the detector address and 8 bits for the status message. Finally, 31 bits are made available for the error detection and correction code.
- Figure 1b shows the division of a channel in the time and frequency domain.
- a bandwidth B transmission channel is available for transmission.
- the bandwidth B is approximately 100 MHz in the 2.4 GHz band, for example.
- With simple modulation methods about 100 Mbit / s can be transmitted.
- Within this bandwidth B is transmitted on different carrier frequencies, which are designated f1-fn in the figure. If one assumes that the carrier frequencies are separated from one another by clear gaps and that, for example, a factor of 10 lies between the bandwidth used and the available bandwidth, 10 Mbit / s can still be transmitted.
- 10 Mbit / s With an information block of length 100 bits, 100,000 information blocks, i.e. 100,000 slots per second, can be transmitted.
- the information block is 10,000 per carrier Blocks of information transferable.
- the selection at which point in time and on which carrier frequency an information block is transmitted is selected at random in the alarm transmitter.
- slot x is used to transmit an information block on the carrier frequency f4 and a slot y on the carrier frequency f n-1 .
- An algorithm is advantageously selected for the transmission, in which an average of k messages per second are sent out on randomly selected slots.
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- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Mobile Radio Communication Systems (AREA)
- Alarm Systems (AREA)
Description
Die Erfindung betrifft ein Verfahren zum Betrieb einer Funkalarmanlage mit
einer Funkstrecke mischen den Außenstationen und der Zentraleinheit einer
Alarmanlage nach dem Oberbegriff des Anspruches 1. The invention relates to a method for operating a radio alarm system
a radio link mix the outstations and the central unit one
Alarm system according to the preamble of
Zur Überwachung von Gewerbe- oder Privatgebäuden werden in der Regel Alarmanlagen installiert, die eine Innenraumüberwachung und eine Außenhautsicherung ermöglichen. Bereits bei vergleichsweise kleinen Gebäuden ist eine Vielzahl von einzelnen Sensoren notwendig, um die einzelnen Räume und deren Zugangsmöglichkeiten, beispielsweise Fenster, zu überwachen.For monitoring commercial or private buildings usually alarm systems installed that a Interior surveillance and an outer skin protection enable. Even in comparatively small buildings a large number of individual sensors is necessary to the individual rooms and their access options, monitor windows, for example.
Um den Installationsaufwand, der durch das Verlegen von Leitungen, die die einzelnen Sensoren und die Zentraleinheit verbinden, zu verringern, wird in der europäischen Patentanmeldung EP 0 253 156 A1 vorgeschlagen, in jedem Raum eine Kommunikationseinheit anzubringen. Diese Kommunikationseinheit wird mit der Zentraleinheit über eine Meldeleitung verbunden. Die einzelnen Überwachungssensoren sind mit einer Sende- und Empfangseinrichtung ausgestattet, so daß sie mit der Kommunikationseinheit drahtlos verbunden werden können. Bei dieser Ausführung einer Alarmanlage verringert sich der Installationsaufwand zwar beträchtlich, es müssen aber immer nach Leitungen in die einzelnen Räume gelegt werden.To the installation effort caused by laying Lines that the individual sensors and the Connect central unit, will decrease in the European patent application EP 0 253 156 A1 proposed a communication unit in each room to attach. This communication unit is with the Central unit connected via an alarm line. The individual monitoring sensors are with a transmit and Receiving device equipped so that it with the Communication unit can be connected wirelessly. This type of alarm system is reduced the installation effort is considerable, it must but always laid according to cables in the individual rooms become.
Eine verbesserte Alarmanlage ist aus der deutschen
Offenlegungsschrift DE 40 35 070 A1 bekannt. Bei dieser
Alarmanlage werden alle Meldeeinheiten, die aus Sensoren
und Sende-/Empfangseinheiten bestehen, direkt über eine
Funkstrecke mit der Zentraleinheit drahtlos verbunden.
Bei einer derartigen Anlage entfallen sämtliche
Installationsarbeiten. Um die vom Verband- der
Sachversicherer gestellten bzw. zu erwartenden
Forderungen an die Betriebssicherheit zu erfüllen, werden
Vorkehrungen getroffen, die eine Fehlalarmauslösung und
eine Blockierung des Alarms verhindern.
Dies wird erreicht, indem, die Meldeeinheiten jeweils zwei
Funksignale abstrahlen, die eine unterschiedliche
Trägerfrequenz aufweisen und in Datentelegrammen fest
vorgegebener Codierung verschlüsselt sind. Weiterhin wird
die Feldstärke der empfangenen Signale der Meldeeinheiten
überprüft und bei Überschreiten eines vorgegebenen
Feldstärkewertes über einen bestimmten Zeitraum wird eine
Warnanzeige ausgelöst.
Mit einer derartigen Alarmanlage können Störungen zwar
gut erkannt werden, so daß sie zur Alarmgabe führen, eine
Störung der Funkstrecke kann damit aber nicht verhindert
werden. An improved alarm system is known from German Offenlegungsschrift DE 40 35 070 A1. With this alarm system, all signaling units consisting of sensors and transmitter / receiver units are connected wirelessly directly to the central unit via a radio link. With such a system, all installation work is eliminated. In order to meet the requirements placed on the operational security by the association of property insurers or to be expected, precautions are taken to prevent a false alarm from being triggered and the alarm to be blocked.
This is achieved in that the signaling units each emit two radio signals which have a different carrier frequency and are encoded in data telegrams of a fixed, predetermined coding. Furthermore, the field strength of the received signals of the signaling units is checked and a warning is triggered if a predetermined field strength value is exceeded for a certain period of time.
With such an alarm system, faults can be recognized well, so that they lead to the alarm being issued, but a fault in the radio link cannot be prevented.
Zur störsicheren Funkübertragung ist aus der
Nachrichtenübertragung weiterhin das
Frequenz-Hopping-Verfahren bekannt. Ein derartiges
Verfahren ist beispielsweise in der deutschen
Offenlegungsschrift DE-A-34 15 032 angegeben. Gemäß
diesem Verfahren werden die Nachrichten oder Daten, die
über Funk zwischen zwei miteinander synchronisierten
Stationen übertragen werden, blockweise aufgeteilt und
übertragen. Dabei wird die Trägerfrequenz in kurzen
Intervallen pseudozufällig-innerhalb eines vorgegebenen
Frequenzbandes verändert. In den Sende- und
Empfangseinrichtungen der Funkstationen ist ein
Codegenerator angeordnet, welcher ein die
Übertragungseinrichtung kennzeichnendes Hoppschema
erzeugt.
Zur weiteren Erhöhung der Übertragungssicherheit werden
die Sprungfrequenzen auf Interferenzstörungen hin
überwacht und die Frequenzen, bei denen häufig Störungen
auftreten, werden zur Übertragung nicht mehr benutzt.For interference-free radio transmission, the frequency hopping method is also known from message transmission. Such a method is given, for example, in German published application DE-A-34 15 032. According to this method, the messages or data which are transmitted by radio between two stations synchronized with one another are divided and transmitted in blocks. The carrier frequency is changed pseudorandomly at short intervals within a predetermined frequency band. A code generator is arranged in the transmitting and receiving devices of the radio stations, which generates a hopping scheme which characterizes the transmission device.
To further increase the transmission security, the hopping frequencies are monitored for interference interference and the frequencies at which interference frequently occurs are no longer used for transmission.
Zur Verbesserung der Übertragungssicherheit und der Erhöhung der Signalübertragungsrate wird in der deutschen Offenlegungsschrift DE-A-41 28 167 vorgeschlagen, bereits während eines gerade übertragenen Blockes oder Rahmens den Sendeempfänger durch den Steuerprozessor auf die bevorstehende Kanalumschaltung vorzubereiten. Im Modem wird am Ende des jeweils laufenden Rahmens ein von der Testsignalfolge dieses Rahmens abgeleitetes Schaltsignal erzeugt und an den Sendeempfänger weitergeleitet. Nach der Detektion dieses Schaltsignales durch den Sendeempfänger wird dort die Kanalumschaltung vorgenommen. Auf diese Weise können die Pausen zwischen den Rahmen bei gleichbleibender Übertragungssicherheit verkürzt werden.To improve transmission security and Increasing the signal transmission rate is in the German DE-A-41 28 167 proposed, already during a block or frame being transferred the transceiver through the control processor to the prepare for upcoming channel switching. In the modem at the end of the current frame, one of the Test signal sequence of this frame derived switching signal generated and forwarded to the transceiver. To the detection of this switching signal the channel changeover is carried out there by the transceiver performed. This way, the breaks between the frame with constant transmission security be shortened.
Das Frequenz-Hopping-Verfahren, wie es aus der Nachrichtentechnik bekannt ist, ist aber für den Einsatz im Bereich der Sicherheitstechnik zu aufwendig, da Sender und Empfänger synchronisiert sein müssen. The frequency hopping process as it emerged from the Telecommunications is known, but is for use too complex in the area of security technology, because transmitters and the receiver must be synchronized.
Es ist deshalb Aufgabe der Erfindung ein Verfahren zum Betrieb einer Funkalarmanlage mit einer Funkstrecke zwischen den Außenstationen und der Zentraleinheit einer Alarmanlage anzugeben, bei welchem Störungen der Funkübertragungsstrecke bei vertretbarem Aufwand reduziert werden können. It is therefore an object of the invention to provide a method for operating a Radio alarm system with a radio link between the outstations and the Central unit of an alarm system to indicate at which faults the Radio transmission path can be reduced with reasonable effort.
Diese Aufgabe wird, ausgehend vom Oberbegriff des
Anspruches 1, erfindungsgemäß durch die kennzeichnenden
Merkmale des Anspruches 1 gelöst.This task is based on the generic term of
Vorteilhafte Ausgestaltungen der Erfindung sind in den abhängigen Ansprüchen angegeben.Advantageous embodiments of the invention are in the dependent claims specified.
Gemäß der Erfindung wird die Sendefrequenz, auf der die Außenstationen ihre Meldungen an die Zentrale senden, nach dem Absetzen eines oder mehrerer Informationsblöcke verändert. Jeder Informationsblock wird dabei mehrfach gesendet, um den Empfang in der Zentrale sicherzustellen. In der Zentrale wird das verfügbare Übertragungsspektrum gescannt. Es findet weiterhin eine Auswertung statt, ob alle gemeldeten Sensoren innerhalb eines vorgegebenen Zeitintervalles eine Meldung abgesetzt haben und ob die Fehlerrate der abgegebenen Meldungen einen vorgegebenen Wert nicht überschreitet. According to the invention, the transmission frequency on which the Outstations send their messages to the headquarters, after sending one or more blocks of information changed. Each block of information becomes multiple sent to ensure reception at headquarters. The available transmission spectrum is in the head office scanned. There is still an evaluation of whether all reported sensors within a given Time interval have sent a message and whether the Error rate of the messages submitted a predetermined Value does not exceed.
Der Vorteil der erfindungsgemäßen Funkalarmanlage resultiert aus der wiederholten Übertragung einer Nachricht unter Verwendung verschiedener Sendefrequenzen. Durch die Verwendung verschiedener Sendefrequenzen werden bandbegrenzte Störer umgangen sowie eine gezielte Sabotage erschwert. Weiterhin werden Fading-Einbrüche durch Reflexionen, die bei schmalbandigen Systemen zur Auslöschung bestimmter Frequenzen führen, durch die Verwendung der verschiedenen Sendefrequenzen umgangen.The advantage of the radio alarm system according to the invention results from the repeated transmission of a Message using different transmission frequencies. By using different transmission frequencies bypassed band-limited interferers as well as a targeted Sabotage difficult. Further fading drops due to reflections that are used in narrowband systems Extinction of certain frequencies through which Bypassed the use of the different transmission frequencies.
Gemäß einer Ausführungsform der Erfindung wird innerhalb
der zur Verfügung stehenden Übertragungsbandbreite eine
vorgebbare Anzahl von Trägerfrequenzen bestimmt, auf
denen die Informationsblöcke übertragen werden. Die
Zeitdauer, innerhalb der auf einer Trägerfrequenz
übertragen wird, entspricht der Übermittlungsdauer eines
Informationsblockes oder eines Vielfachen davon.
Auf diese Weise werden jeweils ein gesamter oder mehrere
gesamte Informationsblöcke auf einer Frequenz
übertragen, bevor auf die nächste Übertragungsfrequenz
umgestellt wird, und die übertragenen Informationen
werden nicht gleichzeitig auf mehrere Frequenzen verteilt
übertragen.According to one embodiment of the invention, a predefinable number of carrier frequencies on which the information blocks are transmitted is determined within the available transmission bandwidth. The period of time within which a carrier frequency is transmitted corresponds to the transmission period of an information block or a multiple thereof.
In this way, one or more or all of the entire information blocks are transmitted on one frequency before switching to the next transmission frequency, and the transmitted information is not transmitted simultaneously over several frequencies.
Gemäß einer weiteren vorteilhaften Ausgestaltung der Erfindung enthalten die einzelnen übertragenen Informationsblöcke einen Synchronisationsblock, einen Nutzinformationsblock und einen Fehlerkorrekturblock. Mit Hilfe des Fehlerkorrekturblockes erfolgt in der Zentraleinheit eine Auswertung der empfangenen Information im Hinblick auf Übertragungsfehler. Diese Übertragungsfehler können zumindest teilweise korrigiert werden. Weiterhin kann aus den Fehlern auf eine gezielte Störung geschlossen werden. Auf diese Weise kann also auf die bei Funkalarmanlagen sonst übliche Überwachung der Empfangsfeldstärke verzichtet werden. Die Fehlerkorrektur kann durch einen Prozessor implementiert werden, der zur Dekodierung der Empfangssignale ohnehin erforderlich ist.According to a further advantageous embodiment of the Invention contain the individual transmitted Information blocks one synchronization block, one Useful information block and an error correction block. With the help of the error correction block in the Central unit an evaluation of the received Information regarding transmission errors. This Transmission errors can be at least partially corrected become. Furthermore, the errors can be targeted Fault can be closed. So this way you can the otherwise usual monitoring of radio alarm systems Reception field strength can be dispensed with. The error correction can be implemented by a processor that is used for Decoding of the received signals is required anyway.
In einer weiteren vorteilhaften Ausgestaltung der Erfindung werden in der Zentrale alle möglichen Übertragungskanäle seriell überwacht. Dadurch kann mit einem Einkanalempfang sukzessive das gesamte Übertragungsband empfangen werden.In a further advantageous embodiment of the Invention are all possible at headquarters Transmission channels monitored serially. This allows using a single channel reception successively the whole Transmission band can be received.
Eine weitere Möglichkeit ist der Parallelempfang mehrerer oder aller möglichen Übertragungsfrequenzen, wodurch die Übertragungssicherheit der Funkalarmanlage weiter erhöht wird.Another possibility is the parallel reception of several or all possible transmission frequencies, whereby the Transmission security of the radio alarm system is further increased becomes.
Eine weitere vorteilhafte Ausgestaltung der Erfindung sieht vor, daß die Abfolge des Überwchungsvorganges für die möglichen Sendefrequenzen nach dem Zufallsprinzip festgelegt wird, um eine noch höhere Störsicherheit der Funkübertragung zu erreichen.Another advantageous embodiment of the invention stipulates that the sequence of the monitoring process for the possible transmission frequencies at random is set to provide even greater immunity to interference To achieve radio transmission.
Im weiteren wird die Erfindung an Hand der Figur 1 beispielhaft erläutert. Die Figur 1 zeigt den Aufbau eines Informationsblockes (Figur 1a) sowie die Aufteilung des Kanals im Zeit- und Frequenzbereich (Figur 1b).The invention is further illustrated in FIG. 1 exemplified. Figure 1 shows the structure an information block (Figure 1a) and the division of the channel in the time and frequency domain (Figure 1b).
In Figur 1a ist ein Informationsblock dargestellt, der
aus einem ersten Synchronisationsblock Sync, einem
nachfolgenden Block mit der Nutzinformation und einem
dritten Block mit einem Korrekturcode besteht.
Ein Informationsblock für Funkalarmanlagen, der von den
jeweiligen Alarmgebern abgestrahlt wird, kann aus weniger
als 100 bit bestehen. Bei dem dargestellten
Informationsblock kann beispielsweise der
Synchronisationsblock Sync aus 24 bit bestehen, der
Nutzinformationsblock aus 32 bit, wobei beispielsweise 24
bit des Nutzinformationsblockes für die Melderadresse und
8 bit für die Statusmeldung vorgesehen werden.
Schließlich werden noch 31 bits für den Fehlererkennungs- und
Korrekturcode zur Verfügung gestellt.FIG. 1a shows an information block which consists of a first synchronization block Sync, a subsequent block with the useful information and a third block with a correction code.
An information block for radio alarm systems that is emitted by the respective alarm transmitters can consist of less than 100 bits. In the information block shown, for example, the synchronization block Sync can consist of 24 bits, the user information block can consist of 32 bits, for example 24 bits of the user information block being provided for the detector address and 8 bits for the status message.
Finally, 31 bits are made available for the error detection and correction code.
Figur 1b zeigt die Aufteilung eines Kanals im Zeit- und
Frequenzbereich.
Für die Übertragung steht ein Übertragungskanal der
Bandbreite B zur Verfügung. Die Bandbreite B beträgt
beispielsweise im 2,4 GHz-Band etwa 100 MHz. Mit
einfachen Modulationsverfahren sind so etwa 100 Mbit/s
übertragbar. Innerhalb dieser Bandbreite B wird auf
verschiedenen Trägerfrequenzen übertragen, die in der
Figur mit f1 - fn bezeichnet sind.
Geht man davon aus, daß die Trägerfrequenzen durch
deutliche Lücken voneinander getrennt sind und
beispielsweise ein Faktor 10 zwischen genutzter und
verfügbarer Bandbreite liegt, können immer noch 10 Mbit/s
übertragen werden. Mit einem Informationsblock der Länge
100 bit sind somit 100.000 Informationsblöcke, also
100.000 Slots pro Sekunde übertragbar.Figure 1b shows the division of a channel in the time and frequency domain.
A bandwidth B transmission channel is available for transmission. The bandwidth B is approximately 100 MHz in the 2.4 GHz band, for example. With simple modulation methods, about 100 Mbit / s can be transmitted. Within this bandwidth B is transmitted on different carrier frequencies, which are designated f1-fn in the figure.
If one assumes that the carrier frequencies are separated from one another by clear gaps and that, for example, a factor of 10 lies between the bandwidth used and the available bandwidth, 10 Mbit / s can still be transmitted. With an information block of length 100 bits, 100,000 information blocks, i.e. 100,000 slots per second, can be transmitted.
Werden innerhalb der vorgegebenen Bandbreite beispielsweise 10 unterschiedliche Trägerfrequenzen vorgesehen und die einzelnen Träger kontinuierlich genutzt, dann wäre pro Träger ein Informationsfluß von 1 Mbit/sec möglich. Bei einer Länge von 100 bit für einen Informationsblock sind somit pro Träger 10.000 Informationsblöcke übertragbar. Be within the given range for example 10 different carrier frequencies provided and the individual carriers continuously used, then there would be an information flow of 1 per carrier Mbit / sec possible. With a length of 100 bits for one The information block is 10,000 per carrier Blocks of information transferable.
Die Auswahl, zu welchem Zeitpunkt und auf welcher
Trägerfrequenz ein Informationsblock übertragen wird,
wird im Alarmgeber nach dem Zufallsprinzip ausgewählt. In
der Figur 1b wird beispielsweise mit Slot x ein
Informationsblock auf der Trägerfrequenz f4 übertragen
und ein Slot y auf der Trägerfrequenz fn-1. Zur
Übertragung wird in vorteilhafter Weise ein Algorithmus
gewählt, bei dem im Schnitt k Meldungen pro Sekunde auf
zufällig gewählten Slots ausgesendet werden.
Die Wahrscheinlichkeit, daß bei Parallelempfang in der
Zentrale eine Meldung eines Sensors verlorengeht, ist
dadurch gegeben, daß ein weiterer Melder gleichzeitig auf
der selben Trägerfrequenz eine Meldung abgibt. Bei 10
Meldern ergibt sich im ungünstigsten Fall eine
Verlustwahrscheinlichkeit von:
The probability that a message from a sensor will be lost when receiving in parallel at the control center is given by the fact that another detector simultaneously issues a message on the same carrier frequency. With 10 detectors, the worst case scenario is a loss probability of:
Geht man davon aus, daß in der Umgebung 10 Alarmanlagen
mit jeweils 10 Meldern vorhanden sind, ergibt sich eine
Verlustwahrscheinlichkeit von:
Die Wahrscheinlichkeit, daß alle Meldungen eines Sensors
verlorengehen ergibt sich zu:
Werden also pro Sensor 10 Meldungen pro Sekunde abgegeben
und enthält die Alarmanlage 10 Melder, ergibt sich ein
Verlust aller Meldungen eines Melders alle 1016 Sekunden,
das entspricht in etwa 317 Millionen Jahren, wenn im
Umkreis der Alarmanlage weitere 10 Alarmanlagen aktiv
sind.
Diese Berechnung zeigt, daß ein sicheres Funktionieren
der Alarmanlage auch bei dichter Belegung gewährleistet
ist, zumal die heutigen Richtlinien nicht wie im
Rechenbeispiel eine Meldung pro Sekunde, sondern nur eine
Meldung in 10 Sekunden vorsehen. Es sind also genügend
Sicherheitsreserven vorhanden, die zur Vereinfachung der
Zentrale genutzt werden können. Insbesondere kann auf den
Parallelempfang verzichtet werden und ein Einkanalempfang
zur Anwendung kommen, d.h. die Trägerfrequenzen werden in
der Zentrale nacheinander gescannt.So if 10 messages per second are sent per sensor and the alarm system contains 10 detectors, all messages from one detector are lost every 10 16 seconds, which corresponds to approximately 317 million years if another 10 alarm systems are active in the vicinity of the alarm system.
This calculation shows that the alarm system functions reliably even when there is a dense occupancy, especially since today's guidelines do not provide one message per second as in the calculation example, but only one message in 10 seconds. So there are enough security reserves that can be used to simplify the control center. In particular, parallel reception can be dispensed with and single-channel reception can be used, ie the carrier frequencies are scanned one after the other in the control center.
Claims (7)
- Method of operating a radio alarm system, having a radio link between the external stations and the central unit of an alarm system, the external stations transmitting in a specified transmission spectrum on a plurality of frequencies and the radio signals containing data telegrams that each represent an event and the central unit being tuned to the radio signals of the external stations belonging to the alarm system, characterized in thatthe transmission frequencies of the external stations are each altered after the transmission of one or more information blocks, each information block being transmitted repeatedly,the centre scans the available transmission spectrum and evaluates whether all the signalled sensors have transmitted a signal within a specified time interval,the centre continuously checks whether the error rate in signals emitted does not exceed a specified value.
- Method according to Claim 1, characterized in that, within the available bandwidth, a specified number of carrier frequencies is determined on which the information blocks are transmitted and the time duration within which transmission takes place on a carrier frequency corresponds to the transmission duration of an information block or of a multiple thereof.
- Method according to Claim 1 or 2, characterized in that the individual information blocks each contain a synchronization block, a useful information block and an error correction block.
- Method according to one of Claims 1 to 3, characterized in that all the possible channels are monitored consecutively in the centre.
- Method according to one of Claims 1 to 3, characterized in that a plurality of or all the transmission channels are monitored in parallel in the centre.
- Method according to one of Claims 1 to 5, characterized in that the change in the transmission frequencies in the external stations and the sequence of the monitoring operation are determined on the basis of the random principle.
- Radio alarm signal comprising external stations and at least one central unit for performing the method according to one of Claims 1 to 6, characterized by means for altering the transmission frequency of the external stations after each transmission of one or more information blocks, each information block being transmitted repeatedly.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4337211 | 1993-10-30 | ||
| DE4337211A DE4337211C1 (en) | 1993-10-30 | 1993-10-30 | Radio alarm system with a radio link between the remote stations and the central unit of an alarm system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0651361A1 EP0651361A1 (en) | 1995-05-03 |
| EP0651361B1 true EP0651361B1 (en) | 2000-04-26 |
Family
ID=6501504
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP94116871A Expired - Lifetime EP0651361B1 (en) | 1993-10-30 | 1994-10-26 | Alarm system with a radio link between the peripheral stations and a central unit |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0651361B1 (en) |
| DE (2) | DE4337211C1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4408268C2 (en) * | 1994-03-11 | 2000-11-02 | Grundig Ag | Procedure for increasing the interference immunity of a radio alarm system |
| DE19505199A1 (en) * | 1995-02-16 | 1996-08-29 | Wolfgang Dipl Ing Sachs | Anti-theft radio alarm installation with in-built security |
| DE19506385C2 (en) * | 1995-02-23 | 2002-03-07 | Peter John Goddard | Wireless hazard detection system and notification procedure |
| DE19539312A1 (en) * | 1995-10-23 | 1997-04-24 | Grundig Emv | Procedure for increasing the transmission security in radio alarm systems |
| SE9700471L (en) * | 1997-02-12 | 1998-08-13 | Telia Ab | radio Alarm |
| DE19757235C2 (en) * | 1997-12-22 | 2000-01-05 | Honeywell Ag | Control system for a building or for one or more rooms in a building |
| DE102008001555A1 (en) * | 2008-05-05 | 2009-11-12 | Robert Bosch Gmbh | Procedure for submitting at least one date |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3415032C2 (en) * | 1983-04-27 | 1985-06-20 | Siemens AG, 1000 Berlin und 8000 München | Method for interference-resistant radio transmission |
| DE3429453C1 (en) * | 1984-08-10 | 1992-05-27 | Siemens Ag | Procedure for secure radio signal transmission |
| DE3521996C1 (en) * | 1985-06-20 | 1990-05-17 | Rohde & Schwarz | Arrangement for recombining a message transmitted by a frequency hopper |
| EP0253156A1 (en) * | 1986-06-25 | 1988-01-20 | Siemens Aktiengesellschaft | Intrusion alarm system |
| EP0293627A1 (en) * | 1987-05-19 | 1988-12-07 | Ascom Radiocom AG | Radio transmission method |
| DE4035070A1 (en) * | 1990-11-05 | 1992-05-07 | Norbert Schaaf | RADIO ALARM SYSTEM |
| DE4128167C2 (en) * | 1991-08-24 | 2001-12-06 | Daimlerchrysler Aerospace Ag | Method for controlling the channel switching in a radio device operating according to the frequency hopping method |
| DE4314282C1 (en) * | 1993-04-30 | 1994-06-01 | Grundig Emv | Radio antitheft alarm, e.g. for home - has optical or electrical sensors to detect fire or break-in and transmits alarm signal via transceiver antennae |
-
1993
- 1993-10-30 DE DE4337211A patent/DE4337211C1/en not_active Expired - Fee Related
-
1994
- 1994-10-26 DE DE59409303T patent/DE59409303D1/en not_active Expired - Lifetime
- 1994-10-26 EP EP94116871A patent/EP0651361B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0651361A1 (en) | 1995-05-03 |
| DE59409303D1 (en) | 2000-05-31 |
| DE4337211C1 (en) | 1994-12-15 |
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