EP0100523B1 - Method for information transmission on a single communication channel, and application of this method, particularly in devices constituting an alarm system - Google Patents

Description

The present invention relates to a method for transmitting information according to claims 1 and 2, as well as an application of this method in particular to an alarm system according to claim 3.

In the fields of transmission or transfer of information, in particular by radio, optical, ultrasonic or carrier current, applied in particular to alarm systems for the protection of goods and people and to automatic systems, comprising transmission means and information reception means, it is particularly advantageous to use a single information exchange channel, the latter being able to be defined as being the use of a single carrier frequency or of a single physical medium for carry out the transmission or transfer of information between transmitters and receivers, the information thus exchanged being liable to disturb each other if several transmitters transmit simultaneously on this same channel and consequently they can make the reception of different information difficult or impossible.

Systems are known in which the different elements communicate with each other by a single transmission loop or by a network. In some of these systems, each transmitter includes a means enabling it to determine at any time whether the network is already in use and whether communication is possible. As soon as the network is free, the transmitter in question transmits the information it has to transmit. In other systems, described in the American review "National Telecommunications Conference 1980" volume 2, at pages 37.4.1 to 37.4.6, in the article by ICHIRO IIDA et al, entitled: "Random access packet switched local computer network with priority function ", the information sent by the transmitters is assigned preambles of different transmission times in order to give them different priority levels. These preambles do not, however, contain any other information than that making it possible to distinguish and prioritize the different issuers.

In other known cases, the transmission or transfer of information capable of being transmitted simultaneously on the same transmission channel consists, in order to differentiate it, either of using different carrier sub-frequencies as in the case of Herzian beams by performing a frequency sharing of the channel used, or by multiplexing the information over time by performing a time sharing of the single channel. The first case leads to the use of expensive and complex modulation, demodulation, and filtering systems both in transmitters and in receivers, and the second case leads to the use of equally complex and costly sampling and multiplexing systems as well. than the need to synchronize between them the multiplexers and the demultiplexers.

In currently known alarm systems and using a single information exchange channel, it is considered sufficiently unlikely that two transmitters, for which a very short transmission time is generally chosen, would transmit at the same time and the most important connections are also made, for example between the central unit and the signaling devices such as sirens, by wires in order to avoid any interference. It has also been proposed in US Pat. No. 4,020,477 to repeat the information to be transmitted successively so as to be sure that at one time or another the information transmitted will be received. This solution does not, however, in itself offer all the guarantees. _NOT

It follows that the state of the art provides no simple and inexpensive solution to the problems posed by the transmission or transfer of information by a single information exchange channel.

The present invention aims precisely to solve, in a simple and economical manner, the main problems posed by the transmission or transfer of information by a single exchange channel when the information is likely to disturb each other when it is transmitted simultaneously, especially in the case where the information to be transmitted is relatively scarce and occurs quite rarely and at random times.

The present invention consequently proposes a method for the transmission, on a single exchange channel in particular of the radioelectric or wired type, of information transmitted in the form of signals of the binary or digital type between several transmitters or groups of transmitters and at least a receiver in which each of the transmitters is capable of transmitting, for a limited period and at random times, by successively repeating the information that it has to transmit.

It therefore appears that the present invention seeks on the one hand to obtain the advantages resulting from the use of a single information exchange channel or of a single frequency of information transmission, which is advantageous because that the number of possible or usable frequencies is limited for technical or legislative reasons, and on the other hand the advantages of a transmission or a transfer of information transmitted in the form of signals of the binary or digital type which, for reasons of reliability of the transmission are repeated.

To solve the problem posed by the transmission of information likely to disturb each other, the method according to the present invention consists in ranking each of said transmitters or groups of transmitters by assigning to each of them a total duration transmission and to select or take into account, during the simultaneous reception by said receiver of signals emanating from different transmitters or groups of transmitters and overlapping partially or completely, the information emanating from the transmitter whose transmission time is the longest.

In a first variant, the method according to the present invention consists, for each of said transmitters, or groups of transmitters, in repeating a different number of times the transmission of the information to be transmitted, the latter being represented by words or successive bits of identical format and duration for each of the transmitters.

In a second variant, the method according to the present invention consists in repeating the same number of times the transmission of the information to be transmitted, the latter being represented by successive words or bits, by assigning to each of said transmitters or said groups of transmitters, a different information transmission duration for each of said transmitters or groups of transmitters.

The hierarchy of the different transmitters among themselves by their different transmission times combined with the repetition of the information to be transmitted is such that it is possible for the receiver to be able to validate the information coming from the transmitter of the highest rank in the event of simultaneous transmission and therefore reception of information from transmitters or groups of transmitters of different ranks. As a result, information from transmitters of lower ranks may be lost or not interpretable.

The method according to the present invention can be applied to the prioritization of the devices making up any installation.

However, it finds a particularly interesting application for the prioritization of the devices making up an alarm system for the protection of property and people and comprising in particular at least one state detection device formed in particular by position sensors in order to perform a perimeter protection and / or at least one movement detection device in order to detect any movement within a volume and / or at least one centralization device and / or at least one signaling device such as for example a siren or a telephone transmitter and / or at least one control device with a view in particular to controlling the centralization device and / or at least one call device using, for example portable and commanding, for example, directly a signaling device some of these devices include transmitting means and others receiving means for exchanging type b information inary or digital on a single exchange channel.

Indeed, in an alarm system where it is sought to obtain the greatest possible trigger security, it is particularly advantageous that the information originating from different transmitters cannot cancel each other out in the event of simultaneous transmission. For example, the emission coming from a state detection device should preferably not mask that of a movement detection device, one signaling an attack on the periphery of the premises to be protected and the other signaling an intrusion already characterized and which therefore presents a more urgent or dangerous character for the goods and people to be protected. Likewise, the transmission of an order to actuate a signaling device emanating for example from the centralization device should preferably prevail over the emission of a detection device again signaling the presence of an intruder already spotted. Likewise, the transmission from the call for help device, which has a certain urgency, must have priority over all the others.

It follows that the application to an alarm system intended for the protection of a room of the process according to the present invention can advantageously lead to prioritizing at least two of the different transmitting devices of this alarm system, in order increasing in importance, as follows: peripheral detection device outside the room to be protected, perimeter detection device on the perimeter of the room to be protected, state or movement detection device inside the room to be protected, centralization device, control device, call for help device. It may be advantageous to prioritize by area the devices from different geographic areas and / or the devices within each geographic area. Furthermore, the same alarm system or installation does not necessarily include all the devices indicated above and may include several of the same type.

The present invention will be better understood from the study of an alarm system in which the various devices composing it communicate with each other by radio and on a single information exchange channel, that is to say on a single frequency. , this alarm system being described by way of nonlimiting example and illustrated diagrammatically by the drawing in which:

• - la figure 2 représente un émetteur particulier prévu pour cette installation;
• - et la figure 3 représente un récepteur particulier prévu pour cette installation.

- Figure 1 shows a diagram of the installation;

• - Figure 2 shows a particular transmitter provided for this installation;
• - And Figure 3 shows a particular receiver provided for this installation.

It can be seen in FIG. 1 that the alarm system represented and generally identified by the reference 1 comprises a series of detection devices generally identified by the references 2, 3 and 4, a device for centralization or central identified generally by the reference 5, a control device of the central identified generally by the reference 6, a device signaling generally identified by the reference 7 and a portable aid call device generally identified by the reference 8. In a more complex installation, the devices could each be in greater number or arranged differently.

In the alarm system 1, the detection devices 2, 3 and 4 and the control device 6 can transmit respectively by radio links 2a, 3a, 4a and 6a information and / or orders to the central unit 5, the control unit 5 can transmit actuation orders via a radio link 5a to the signaling device 7 and the call for help device can transmit actuation orders via a radio link 8a directly to the signaling device 7. The connections radio frequencies 2a, 3a, 4a, 5a, 6a and 8a take place on a single information exchange channel which is in the example a single carrier frequency.

For this purpose, the detection devices 2, 3 and 4, the control unit 5, the control device 6 and the call for help device 8 respectively comprise transmitters 9, 10, 11, 12, 13 and 14 and , the central unit 5 and the signaling device 7 respectively comprise receivers 15 and 16.

The detection devices 2, 3 and 4 can be devices for detecting state or change of state, for example devices for detecting the position or changing the position of closing elements such as windows or doors or devices for detecting movement of these closing elements, or devices for detecting movement within a determined space or volume. In one example, it is considered that the detection devices 2 and 3 are state detection or state change devices and for this purpose comprise state or state change sensors 17 and 18 respectively capable of supply their transmitters 9 and 10 respectively with transmission orders and the detection device 4 is a volumetric protection device comprising for this purpose a motion detection sensor 19 capable of supplying transmission orders to its transmitter 11.

The control device 6 is a control device for example of on-off of the central 5 and for this purpose comprises a control member 20 provided for example with a button of a key or a keyboard maneuverable manually in view provide transmission instructions to the transmitter 13.

As we have seen, the central unit 5 comprises a receiver 15 and a transmitter 12. Between this receiver and this transmitter, the central unit 5 comprises a member 21 for processing information coming from the receiver 15 in order to supply, as the case may be , issuing orders to the issuer 12.

In addition to its receiver 16, the signaling device 7 comprises for example a siren 22 capable of being triggered on the order of the receiver 16.

The device for calling for help 8, which in a variant may be of the portable type, comprises a member 23 capable of supplying transmission orders to its transmitter 14 when it is actuated, for example, by a manual button.

Referring to Figure 2, we will now describe a transmitter generally identified by the reference 24 and capable of forming the transmitters 9, 10, 11, 12, 13 and 14 of the alarm system 1 shown in the figure 1. This transmitter 24 is designed to transmit information of the binary type contained in eight-bit words as will be seen below.

This transmitter 24 comprises an input line 25 capable of receiving, at a random moment, an order to transmit from a member 26 formed for example by one of the sensors 17, 18, 19, the processing member 21, or one of the control members 20 and 23.

The order arriving by the input line 25 acts on a flip-flop 27 which unlocks the reset input of a binary counter 28. The latter then starts to count at the frequency of a clock 29.

The first two binary output lines 30 and 31 of the binary counter 28 are connected to the inputs of a bit generator 32 and its next three binary output lines 33, 34, 35 are connected to the three inputs of a multiplexer 36 whose output is connected to the bit generator 32 so that the bit generator 33 provides on its output line 37, to a transmitting member 38 connected to an antenna 39 and via a gate 40, the another input is connected to the sixth binary output of the binary counter 28 by line 41, the information to be transmitted displayed to the eight inputs of the multiplexer 36, this information being contained in a programming member 42, formed, in the example shown, by eight switches that can occupy either a closed position or an open position, the value of the eight bits representing this information appearing in series per eight-bit word on the output line 37 of the bit generator 32 to be sent.

The binary counter 28 is capable of generating successively, on the lines 37 of the bit generator 32, several times the word contained in the programming member 42 and representing the information. This number is determined by the choice of one of its outputs 43 by connecting it to the reset input of flip-flop 27 by line 44.

It can be noted that the sixth output line 41 of the binary counter 28 is connected to the gate 40 and serves to inhibit the transmission between two words to allow the receiver which will be described later with reference to FIG. 3 to synchronize .

In addition, the frequency of the clock 29 can be modified by modifying its time constant determined by one of the resistors 45, 46 and 47 and the capacitor 48. Other resistors and other capacitors could be provided.

It appears from the above that the transmitter 24 makes it possible to transmit information of binary type the content of which is determined by the word represented in the programming member 42, having the information contained in the binary word successively repeated a number of times determined by the choice of one of the outputs 43 of the binary counter 28, and to fix a total duration of emission by the choice of one of the resistors 45,46,47 determining the time constant of the clock 29.

With reference to FIG. 3, we will now describe a receiver generally identified by the reference 49 and capable of receiving binary information coming from a transmitter similar to the transmitter 24 represented in FIG. 2 this receiver 49 being capable of forming respectively the receivers 15 and 16 of the alarm system 1 shown in FIG. 1.

The receiver 49 comprises an antenna 50 connected to a reception member 51 supplying on its output line 52 the binary information received in series.

The output line 52 of the reception unit 51 is connected to a bit decoder 53 capable of extracting the information contained in each bit so as to record it and gradually store it in two shift registers 54 and 55 to eight bits connected in series, the output line 52 being also connected to a bit synchronization unit 56, the output of which is connected to the clock inputs of the bit decoder 53 and of the shift registers 54 and 55. The eight parallel outputs shift registers 54 and 55 are connected to a word comparator 57 whose order of comparison of the two words it receives from shift registers 54 and 55 is supplied to it by a word synchronizer 58 activated by the output line 52 of the receiving agency 51.

As soon as the two eight-bit words contained in the shift registers 54 and 55 are identical, the word comparator 57 provides a gate 59 with an order to transfer the eight-bit word contained in the shift register 55 representing the information received and decoded to a processing device 60. This control device 60 can be, in the example, either the processing device 21 or a device for actuating the siren 22.

In order to be able to decode in parallel information represented by words and bits of different duration and / or format received by the single receiving member 51, provision is made, between the receiving member 51 on its output line 52, and the processing member 60 of the assemblies generally identified by the references 61 and 62 identical to that which has just been described, their synchronization members not having the same time constants. It is thus possible, with the same receiving member 51, to receive information of different formats and duration in any number.

. It follows from the above that the receiver 49 is particularly suitable for taking into account information contained in a binary word as soon as it has successively received two identical words representing this information.

We will now describe how it is possible to adapt the transmitter 24 and the receiver 49 shown respectively in FIGS. 2 and 3 to the alarm system 1 represented in FIG. 1, with the aim that this alarm system has a greatest possible trigger safety.

It should be noted that in an alarm system such as that shown in FIG. 1, it is particularly advantageous that certain radio links have priority over others in the event of simultaneous transmission. It is therefore interesting to prioritize the devices making it up.

Indeed, it can be considered that the link 4a between the motion detection device 4 and the central unit 5 must have priority over the links 2a and 3a between the state detection devices 2 and 3 in order to be taken into account. by the control unit 5, given that the movement detection device 4 is placed, as we have seen, inside a room and that the state detection devices 2 and 3 are placed, in general , at its perimeter, the motion detection device 4 detecting an intruder already introduced into the room. In addition, so that at least one of the links 2a and 3a of one of the state detection devices 2 and 3 and the control unit 5 is taken into account by this control unit, it can be considered that the detection device status 3 has priority over status detection device 2.

It can be considered advantageous that the link 5a between the central unit 5 and the signaling device 7 has priority over the links 2a, 3a and 4a then that it transmits an actuation order to the siren 22.

It can also be considered that the link 6a between the control device 6 and the central unit 5 has priority over the links 2a, 3a, 4a and 5a, since the purpose of this control device 6 is to control the operating state of the control unit 5.

We can finally consider that the link 8a between the call for help device 8 and the signaling device 7, which has an emergency nature, as we saw previously, must have priority over all the others.

The devices forming the alarm system are therefore preferably prioritized in the following manner: state detection device 2, state detection device 3, movement detection device 4, central unit 5, control device 6, and device call for help 8.

The transmitter 24 and the receiver 49 are particularly suitable for being able to achieve this hierarchy.

In fact, it has been seen that the receiver 49 is adapted to take into account information as soon as it has successively received two identical binary words representing this information, and that it can be provided to be able to decode words and bits of duration and / or different formats.

We have also seen that the transmitter 24 can transmit a binary word representing a information a number of times determined by the choice of one of the outputs 43 of the binary counter 28. Then, as the receiver 49 is able to take into account information insofar as it receives it twice successively, it is necessary that the minimum difference in the number of repetitions of the same words of identical format and duration by two hierarchically contiguous transmitters 24 must be four words so that the receiver can take into account the information of the hierarchically highest transmitter if these two transmitters transmit simultaneously. In general, it can be noted that this difference (n _l -n _o ) in the number of repetitions (n _o and n,) between two contiguous hierarchical levels must be at least equal to twice the number (k) of words identical successive that the receiver must receive to take into account the information contained in the word, this inequality being n, -n _o > 2k.

We have also seen that the transmitter 24 is adapted to transmit words of different formats by choosing a particular time constant for the clock 29, for example by choosing one of the resistors 45,46,47 and that the receiver 49 can decode words of different format and duration. If we consider that the number of words transmitted is n, that the duration of non-priority words is d _o and that the duration of priority words is and that the receiver must receive k identical successive words, for example two in the case of receiver 49, for information to be taken into account, the total transmission time d, of the word containing the priority information must be at least equal to the total transmission time d _o of the words containing the non-priority information multiplied by the number n of words transmitted divided by the difference between the number n of words transmitted and twice the number k of identical successive words, this inequality being d,> d _o xn / n - 2k.

Applied to the alarm system 1 represented in FIG. 1, the detection device 2, the detection device 3, the detection device 4, the control unit 5 and the device for calling for help 8 can be prioritized. sending words of the same format and the same duration and modifying the number of repetitions of the word for each of these devices while the control device 6 can be ranked by choosing a word of different format, so as to be able to discriminate between device compared to all the others.

In an example in which the number of repetitions has been deliberately increased, it has been chosen that the transmitter 9 of the detection device 2 repeats a word eight times during 128 milliseconds, which leads to a total transmission time of 1024 milliseconds that the transmitter 10 of the detection device 3 repeats the word sixteen times, which leads to a total transmission time of 2048 milliseconds, that the transmitter 11 of the detection device 4 repeats the word twenty-four times, which leads to a total transmission time of 3,072 milliseconds, and that the transmitter 12 of control panel 5 repeats the word thirty two times, which leads to a total transmission time of 4,096 milliseconds, while for the transmitter 14 of the call device using 8 is chosen for safety, a number of repetitions of the word much greater to lead to a total duration of transmission for example greater than thirty seconds.

In this same example, we choose that the transmitter 13 of the control device 6, which, as we have seen, must have priority over devices 2, 3, 4 and 5, repeats a word thirty-two times for 256 milliseconds, which leads to a total transmission duration of 8,182 milliseconds, the transmission duration of this word being equal to twice the transmission duration of each word chosen for the transmitters of devices 2, 3, 4 and 5.

With regard to the receiver 15 of the centralization device 5, it should be noted that it comprises, in this example, a single reception member 51 and two decoding assemblies connected after this reception member 51 taking into account the fact that it must be able to decode two words of different duration.

The present invention is obviously not limited to the example described above. We can indeed consider prioritizing installation devices other than alarm systems and in particular using a single exchange channel other than radioelectric, in particular of the carrier current, optical, sonic or wired type.

Claims (5)

1. Process for transmitting and ranking, in a single exchange channel, particularly of the radioelectric or wired type, information transmitted in the form of signals of the binary or digital type between several emitters or groups of emitters and at least one receiver, in which each of the emitters is capable of emitting, for a limited period and at random times, repeating in succession the information which it has to transmit, which process is characterized in that it consists in ranking each of the said emitters or groups of emitters by allotting to each of them a different total emission period while repeating a different number of times the emission of the information represented by successive words or bits of a format or a duration which is identical for all the emitters, and in selecting or taking into account, during the reception by the said receiver of signals issuing from the different emitters or groups of emitters and partially or completely overlapping each other, the information issuing from the emitter whose emission period is the longest.

2. Process for transmitting and ranking, in a single exchange channel, particularly of the radioelectric or wire type, information transmitted in the form of signals of the binary or digital type between several emitters or groups of emitters and at least one receiver, in which each of the emitters is capable of emitting, for a limited period and at random times, repeating in succession the information which it has to transmit, which process is characterized in that it consists in ranking each of the said emitters or groups of emitters by allocating to each of them a different total emission period while repeating the same number of times the emission of the information represented by successive words or bits of a different duration of emission, for each of the said emitters or the said groups of emitters and in selecting or taking into account, during the reception by the said receiver of signals issuing from different emitters or groups of emitters and partially or completely overlapping each other, the information issuing from the emitter whose period of emission is the longest.

3. Application of the process according to either of Claims 1 and 2 to the ranking of the emitting devices of an alarm system intended to protect premises comprising in particular at least one state detection device and/or at least one movement detection device and/or at least one centralization device and/or at least one signalling device and/or at least one control device and/or at least one device for summoning assistance, devices which comprise means of emission and/or means of reception with a view to exchanging data of a binary type in a single exchange channel.

4. Application according to Claim 3, in which at least two of the emitter devices of the alarm system are ranked, in increasing order of importance, in the following manner: peripheral detection device placed outside the premises to be protected, perimetric detection device placed on the perimeter of the premises to be protected, state or movement detection device placed inside the premises to be protected, centralizing device, control device, device for summoning assistance.

5. Application according to either of Claims 3 and 4, to the ranking by regions of the devices of different geographical regions of the premises to be protected.

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