EP1282094B1 - Method for wireless transmission in an alarm system - Google Patents

Abstract

The method involves switching on the receiver cyclically at defined time points, a substation (1,4,7) intending to send transmitting a preamble, a receiver (3,6,9) remaining on until the end of a preamble and switching off again if there is no preamble. The starting time of a data message is contained in the preamble. The receiver switches off after receiving the starting time and switches on again at this time.

Description

The invention relates to a method for radio transmission in a danger detection system according to the preamble of patent claim 1.

Funk is a nearly ideal transmission medium for building technology. Devices with radio technology are quick to install and easy to adapt to changing requirements. However, a disadvantage is the relatively short range in buildings with carrier frequencies in the gigahertz range. If so-called repeaters are used to increase the range, the high energy consumption still requires mains-powered devices. This is especially true for radio equipment in the new SRD band between 868 and 870 MHz.

In systems with repeaters to increase the range of information across multiple stations in a short time must reach their destination. This short time is measured in terms of building security (fire alarm, intrusion protection) in just a few seconds and in building automation (lighting systems) in less than a second.

However, powerful computers are needed to find the right path through a widely ramified network. It probes probabilities, preselects paths, creates statistics, etc. All this requires space, computing power, and last but not least lots of electrical energy. Even a year-long supply of batteries is currently not possible.

Document D1 ( WO-A-0143350 ) describes a radio link with transmitters and with a receiver which transmits data packets of a data stream at regular intervals. To receive the data packets, the data stream is in a snap mode sampled for the presence of data packets. In addition, times for an expected input of each data packet are predetermined. In a transmission mode, a data packet is sampled at regular time intervals, it being determined from a comparison of a test code with the content of the data packet whether a faultless data packet is present.

Out EP 0 911 775 a method for radio transmission in a hazard detection system is known, which is suitable for battery operation. In this case, an acknowledgment signal is output from the central office for routine signals from peripheral elements sends, which is used by ready-to-send peripheral elements as a start signal for the transmission of detector data to the control center. In the case of several available radio channels, the routine signals are transmitted in successive channel time slots on changing radio channels and the acknowledgment signals are expected until an acknowledgment signal is received in a time slot with a connection. This acknowledgment signal receives a ready-to-transmit peripheral element, which then transmits its detector data to the control center in the next time slot for detector data transmission on the same radio channel which is recognized as free. This process is characterized by minimal energy consumption in conjunction with short monitoring and reaction times in the seconds range. A disadvantage is the relatively complex procedure and the long reaction times in the repeater mode. Since the participants of the system must keep in sync, they must synchronize their internal clocks. This results in a relatively large radio load and as a result, the need for multiple radio channels.

Out DE 19905 316 a data transmission system, in particular for consumption data acquisition, is known, which has at least one transmitter and one receiver for receiving data packets that are sent at intervals from a respective transmitter. The receiver comprises a timing device for timing its receive operation, which estimates the respective time of the expected next data transmission on the basis of desired values for the time intervals of successive data packets of the respective transmitter and the receiver temporarily each in a tolerance interval, the estimated time of the expected next Estimates the data transmission and temporarily switches the receiver to reception in each case within a tolerance interval containing the estimated time. The length of the data packets is limited to the tolerance interval.

It is therefore an object of the invention to provide a method for radio transmission in a hazard detection system, which is suitable for the repeater operation, ensures short reaction times, works to save energy and allows flexible data telegram lengths.

The object is achieved by a method for radio transmission of the type mentioned above with the characterizing features of claim 1.

In this case, the receiving devices of the subscribers are cyclically switched on at predetermined times, and send-willing subscribers send preambles which contain the address of the subscriber who is to receive the preamble. If a receiving device now receives one of the preambles which is addressed to this receiving device, the receiving device remains switched on until the complete preamble has been received, and in the event that no preamble has been received, the receiving device is switched off again. It is provided that in the preamble, only the start time of the actual data telegram is transmitted, and the receiving device turns on at this start time and the transmitting party sends out the corresponding data telegram at this start time. This procedure ensures that the receivers remain operational for a few years via a battery, for example a low-cost AA cell.

The radio traffic can be further reduced by sending the preamble only once in the case of a desired transmission to several participants intended for reception and the associated reception devices remain switched on until the preamble has been received.

In the advantageous embodiment of the method according to claim 2, the receiving device changes in the on state, the frequency of the receiving frequency to meet the currently valid in the US FCC rule for frequency hopping.

According to claim 3, the cycles are selected so that the time interval in which the receiving device is turned off compared to the time interval in which the receiving device is switched on by more than a factor of 5, the corresponding data telegram is sent out to this start time.

In order to build the largest possible danger network, it is provided in accordance with claim 4, that telegrams are transmitted by send participants to participants intended for reception via so-called. Mediating participants and that in a memory device of the participants a list is stored in which the addresses of the mediating Participants are saved.

For the joint achievement of different participants is provided according to claim 5 in an advantageous manner that this list also includes a group affiliation.

In methods in which the frequency is changed, it is advantageously provided according to claim 7 that in the list is also noted, over which frequency channel of the intended for receiving participants can be achieved.

In accordance with claim 8, a method with frequency change can be made simpler by the fact that a change of the frequency channels takes place according to an education law known to all participants.

According to claim 9 is provided in a disturbance of the transmission between two participants, that for the reception provided participants also on other - then mediating - participants is achieved.

According to claim 10 is provided in an advantageous manner that an excellent participant optimizes the lists of other participants and sends these optimized lists to the other participants.

A particularly simple configuration method according to claim 11 provides that the participants themselves are brought into a configuration mode during initial commissioning, in which the participants search for the other participants and include them in their lists when they are found. This minimizes the configuration effort.

In the following the invention will be explained in more detail with reference to the figures in the drawing.

• Figur 1 eine schematische Ansicht eines Gefahrenmeldesystems mit drei Teilnehmern,
• Figur 2a und 2b Beispiele für Listen, wie sie in der Speichereinrichtung abgespeichert sind,
• Figur 3a und 3b die Listen zweier Teilnehmer im Konfigurationsmodus, die Figuren 4a, 4b und 4c die Listen von drei Teilnehmern im Konfigurationsmodus,
• Figur 5 die Liste eines Teilnehmers, in der zusätzlich die Gruppenzugehörigkeit der verschiedenen Teilnehmer eingetragen ist und
• Figur 6 die Liste eines Teilnehmers mit Frequenzkanälen, die für die Übertragung vorgesehen sind.

Show

• FIG. 1 shows a schematic view of a hazard detection system with three subscribers,
• FIGS. 2a and 2b show examples of lists as stored in the memory device,
• FIGS. 3a and 3b show the lists of two subscribers in the configuration mode; FIGS. 4a, 4b and 4c show the lists of three subscribers in configuration mode;
• FIG. 5 shows the list of a subscriber in which additionally the group affiliation of the different subscribers is entered and
• Figure 6 shows the list of a subscriber with frequency channels, which are intended for transmission.

FIG. 1 shows how a first subscriber 1 is equipped with a first transmitter 2 and a first receiver 3, the first subscriber 1 being equipped with a second subscriber 4 (which likewise comprises a second transmitter 5 and a second receiver 6) and with a third participant 7 (with a third transmitter 8 and a third receiver 9) forms a hazard detection system. The individual subscribers 1, 4, 7 can have, for example, additional sensors which, for example, detect a fire hazard or detect a burglary attempt as motion detectors. In addition, subscribers 1, 4, 7 can also assume central functions, for example initiate an alarm or display a building view with the corresponding alarm locations. It is also conceivable that the individual participants have 1,4,7 actuators to close doors, turn on lights or set blinds in motion.

The necessary RF receivers in the range of 1 GHz today typically consume 10 to 30 mA from 3 V. The life of a battery should be about 4 years. For low-cost AA cells (mignon), such a current is 300 to 1000 times larger.

According to the invention, the receiver checks regularly (for example every 300 ms) whether a subscriber willing to send is active. The settling time of the receiver must be so small that the resulting average current does not load the batteries too much. Settling times of less than 1 ms are currently technically possible.

A subscriber willing to send now sends a preamble that allows the recipient to recognize the request. In the present example, this preamble must be sent for 300 ms to ensure that the subscriber intended for reception then also has its receiver switched on.

Additional information in the preamble indicates the start time of the actual telegram. The receiver is then turned off again until the beginning of the payload and thus can save power.

To comply with the US FCC Frequency Change Policy, the frequency of the receiving channels will be changed during the time the receiver is turned on.

If a station willing to send has to make contact with several other subscribers, the preamble is sent out only once and the associated subscribers intended for receiving do not switch off immediately but wait for the telegrams to be exchanged.

For the organization of the network, it is provided that in a radio cell with, for example, n-subscribers, each subscriber keeps a list that provides information about which next subscriber (mediator) that can reach any other subscriber of the radio cell. Such a list is shown by way of example in FIG. 2a. In this list for the subscriber 7, the subscriber to be reached is entered in the first line and the first mediator provided for this purpose in the second line. The subscriber 7 shown in FIG. 2a reaches the subscribers 5, 6 and 8 directly, while the subscribers 1 to 4 can be reached via the subscriber 5, the subscribers 9 and 10 can be reached via the subscriber 6. In this case, the statement that the subscriber 2 is to be reached via the subscriber 5 does not mean that the subscriber 5 has direct contact with the subscriber 2. A further mediator can certainly be provided, as shown in the exemplary list of the subscriber 5 in FIG. 2b.

According to the invention, it is provided that the first-time extraction of the list is done without an additional tool. For this purpose, the following steps are performed: first, the first participant of the radio cell is brought into a configuration mode. The subscriber searches for existing subscribers in configuration mode. Since the first party does not find another such party, that party itself defines a cell number and waits for other participants to log in to it. The second station of the radio cell is put in the configuration mode. He finds the participant 1 and proceeds in such a way that he is the number 2 himself. Both have now each occupied a place in their list, as shown in Figure 3a for the participant 1 and Figure 3b for the participant 2.

Subsequently, the third party is brought into the configuration mode. If, for example, he finds only subscriber 2, but not subscriber 1, he can have his list transmitted to him. Thus, the third participant knows that he can reach the participant 1 via the participant 2 and is integrated as participant 3 into the system. The participant 2 now transmits to the participant 1 that the participant 3 can reach him (the participant 2). The corresponding stored lists then correspond to the participant 1 of FIG. 4a, to the participant 2 of FIG. 4b and to the participant 3 of FIG. 4c.

If the connection between two subscribers n and m is lost, n tries to re-establish the connection via another subscriber. For this purpose, this participant turns to the participants, which he can reach directly and checks whether they have contact to n. If so, the participant will correct his list accordingly. For the participant m the corresponding applies.

FIG. 5 shows that each subscriber of a radio cell can be assigned to one or more functional groups. These functional groups are mapped in further lines of the lists, as shown in Figure 5 with the letters A, B and C. In this case, each participant, as shown, at the same time belong to several groups, as it is in the example of the participants 6, who also belongs to the groups A and B. With the help of such groups, for example, lamp collectives can be switched together.

If a broadcast message is now sent to such a group, and a subscriber receives such a message and belongs to the specified collective, he executes the command, even if he is not addressed directly to him. In this case, a receipt is omitted. In this way, the reaction time of a group can be drastically shortened. A following directly addressed command with the same content has no effect, but is acknowledged. To optimize the lists, it is envisaged that an excellent subscriber of the cell has the right to optimize the list of other subscribers. For this purpose, this excellent participant collects the lists of all participants and optimizes them on the basis of, for example, further attributes of the connections such as field strength or error frequency. After the winning subscriber has optimized the cell's connection network, he returns the lists back to each subscriber.

For systems with frequency changes, it is additionally provided that it is shown in the lists via which frequency channel the respective subscriber can be reached in the next cycle. Such an example is shown in FIG. The list shown in Figure 6 applies to the participant 5. If this sends a telegram to the subscriber 8, he turns to the subscriber 7 and uses the frequency channel No. 12. Since the channel numbers must be changed regularly, this has in Frame of normal telegrams to happen. The future channel number of the old telegram will be indicated.

If the channel change is performed according to an education law known to all subscribers, then even in the case in which a telegram is lost, the corresponding partner can einphasen by the fact that he tries to recreate the contact via the subsequent channels according to the Bildgesetz.

This represents a power-saving, spontaneously responding radio system, which enables battery-powered repeaters. However, the microcontrollers used need only a small main memory. Despite the possibility of autorouting, one word per station is sufficient for the radio cell.

Claims (11)

1. Method for radio transmission in an alarm system with a plurality of stations (1,4,7) each comprising a transmitter (2,5,8) and a receiver (3,6,9),
   wherein the receivers (3,6,9) are cyclically activated at specified times,
   stations wishing to transmit send a preamble,
   in the event of a preamble being received, the receivers (3,6,9) remain activated until the end of the entire preamble, and, in the event of no preamble being received, are deactivated again,
   the start time of a data telegram is communicated in the preamble,
   on receiving the start time, the receiver (3,6,9) is deactivated and reactivated again at said start time,
   at said start time, the station wishing to transmit (1,4,7) sends out the telegram via its transmitter (2,5,8) and this is received by the receiver (3, 6, 9),
   characterised in that, if transmission to a plurality of stations intended to receive (1,4,7) is required, the station wishing to transmit (1,4,7) sends out the preamble with the associated receive addresses only once.
2. Method for radio transmission according to claim 1,
   characterised in that the stations change the frequency channel.
3. Method for radio transmission according to one of claims 1 or 2,
   characterised in that the time interval during which the receiver (3,6,9) is deactivated is greater by a factor of 5 than the time interval during which the receiver is activated (3,6,9).
4. Method for radio transmission according to one of claims 1 to 3,
   characterised in that telegrams are sent by stations wishing to transmit (1,4,7) to a station intended to receive (1,4,7) via one or more intermediary stations (1,4,7) and
   that in a memory device of the stations (1,4,7) a list is stored containing the addresses of intermediary stations (1,4,7) via which the stations intended to receive (1,4,7) are reached.
5. Method for radio transmission according to claim 4,
   characterised in that a plurality of stations (1,4,7) are combined into a group and the group membership is likewise recorded in the list.
6. Method for radio transmission according to claim 5,
   characterised in that certain telegrams are sent to a group and the content of said certain telegrams is complied with by all the stations belonging to the group addressed.
7. Method for radio transmission according to one of claims 4 to 6, referring back to claim 2,
   characterised in that the list records the frequency channel via which the corresponding station (1,4,7) can be reached.
8. Method for radio transmission according to claim 7,
   characterised in that the frequency channels are changed in accordance with a formation rule known to all the stations (1,4,7).
9. Method for radio transmission according to one of claims 4 to 8,
   characterised in that if the connection between two stations (1,4,7) is lost, the station wishing to transmit (1,4,7) interrogates all the stations reachable directly without the help of the intermediary stations (1,4,7) to ascertain whether the station intended to receive (1,4,7) can be reached from these reachable stations (1,4,7),
   that if the station intended to receive (1,4,7) can be reached via another directly reachable station (1,4,7), the list is corrected accordingly in the station wishing to transmit (1,4,7).
10. Method for radio transmission according to one of claims 4 to 9,
    characterised in that the lists of all the stations (1,4,7) are communicated to a designated station (1,4,7),
    that said designated station (1,4,7) optimises the lists of the other stations (1,4,7) and
    that the designated station (1,4,7) sends the optimised lists to the other stations (1,4,7) which store them in their memory unit in place of the original list.
11. Method for radio transmission according to one of claims 4 to 10,
    characterised in that for configuring the stations (1,4,7) the latter have a configuration mode in which the stations (1,4,7) look for other stations (1,4,7) in configuration mode and, if other stations (1,4,7) are found, incorporate them in their list,
    that information concerning the stations (1,4,7) which have not been found directly in configuration mode is transmitted to these stations (1,4,7) via the intermediary stations (1,4,7), whereupon these stations (1,4,7) supplement their lists.

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