Communication system, in particular for alarms and method for its operation

Technical area

0001The invention relates to a communication system, in particular for hazard warning systems from interlinked hazard detectors, and a method for operating such a communication system, as well as a communication terminal using the method for use in the communication system.

State of the art

0002In the case of permanently installed communication systems, changes in the transmission paths always lead to a deterioration in the transmission quality and to the loss of communication, both in the case of line-bound and non-conducting transmission sections, even after careful installation. This is often due to changes in the surrounding area, such as new walls or furniture, which result in a higher signal attenuation or reflections. In the case of line-connected systems, creeping short circuits or interruptions in the communication lines due to reflections and increased attenuation lead to impairments in communication. Especially in the case of safety systems such as hazard warning systems for signaling to hazards such as smoke, fire and gas, a secure communication among the system subscribers is necessary. From the<patcit id="pcit0001" dnum="US4754261A"><text>U.S. 4,754,261</text></patcit> A danger notification system is known in this respect in which the receivers are brought into an installation mode during the system installation in which the received signal at the receiver is disturbed and therefore a reception signal of higher quality is required than in normal operation. If the receivers in the installation mode can receive all transmitters of the system, a quality reserve for the communication in normal operation is assumed. The<patcit id="pcit0002" dnum="EP0874341A"><text>EP0874341</text></patcit> Proposes to reduce the transmission energy compared to normal operation during the installation of an alarm system. The receivers that are installed are changed to their position until a position is found at which the signals transmitted with a lower transmission power can be received.

0003Both systems limit the communication range during the installation of the system and can only detect faults during this phase. They also require additional switching elements in the transmission or reception circuit, which can switch between different power stages during transmission or reception, and are inflexible with regard to range control and limited to the installation mode. In the embodiment shown in FIG<patcit id="pcit0003" dnum="US5801626A"><text>US 5,801,626</text></patcit> , Transmission errors can also be detected after the installation phase. Separate monitoring signals are sent to check for undisturbed reception. When a signal is received, the signal strength is measured and determines whether it is a monitoring signal. When the received signal is a monitoring signal, the measured signal strength is compared with a fixed threshold value. If the measured signal strength exceeds the threshold value, the monitoring signal is discarded and not answered. For all other signals, the reception strength is not taken into account. Also from the<patcit id="pcit0004" dnum="US20110014910A"><text>US 2011/0014910</text></patcit> It is known to measure the signal strength of a signal and to compare it with a threshold value. However, the threshold value is here determined in the receiving device on the basis of the signal strength which is measured during the reception of at least a part of the signal, for example, of the preamble. If the signal strength exceeds the threshold value determined by means of the measured values, the signal is further processed, otherwise it is discarded. The latter reduces the interfering influence of adjacent systems, but remains susceptible to errors when, for example, a weak signal is received as a first signal and therefore the threshold value is determined too low, and the range can also not be influenced here in a targeted and flexible manner.

Object of the invention

0004SUMMARY OF THE INVENTION The object of the invention is therefore to provide an operating method, a communication system and a communication terminal, in particular for communication in danger sign systems which do not have the disadvantages of the prior art, or at least defuse them.

Description of the invention

0005The solution of the object is carried out according to the features of the claims and is described in more detail below.

0006In a method according to the invention for operating a communication system, a limit value for the reception strength of a receiver in a telegram to be transmitted is provided for controlling the communication range. For this purpose, a transmitting system subscriber selects, for example, a smoke alarm detector, depending on its operating mode or the type of the receiving device, a limit value and, for example, inserts it into the header of a telegram to be sent. The receiving circuit, which can switch between different power stages during transmission or reception and are inflexible with respect to the range control, and are limited to the installation mode. In the embodiment shown in FIG<patcit id="pcit0005" dnum="US5801626A"><text>US 5,801,626</text></patcit> , Transmission errors can also be detected after the installation phase. Separate monitoring signals are sent to check for undisturbed reception. When a signal is received, the signal strength is measured and determines whether it is a monitoring signal. If the received signal is a monitoring signal, the measured signal strength is compared with a fixed threshold value. If the measured signal strength exceeds the threshold value, the monitoring signal is discarded and not answered. For all other signals, the reception strength is not taken into account. Also from the<patcit id="pcit0006" dnum="US20110014910A"><text>US 2011/0014910</text></patcit> It is known to measure the signal strength of a signal and to compare it with a threshold value. However, the threshold value is here determined in the receiving device on the basis of the signal strength which is measured during the reception of at least a part of the signal, for example, of the preamble. If the signal strength exceeds the threshold value determined by means of the measured values, the signal is further processed, otherwise it is discarded. The latter reduces the interfering influence of adjacent systems, but remains susceptible to errors when, for example, a weak signal is received as a first signal and therefore the threshold value is determined too low, and the range can also not be influenced here in a targeted and flexible manner. Moreover, the<patcit id="pcit0007" dnum="WO2006102183A2"><text>WO 2006 102 183 A2</text></patcit> A system for the monitoring and control of shopping carts became known. In this system several access points or basic units are distributed in the rooms and on the premises of a business. The access points send in part different commands received by transceivers in shopping carts. To limit a transmission or reception area of ​​the access points, fixed RSSI limits (reception strength limits) are defined, which are transmitted in each telegram transmitted via the antenna of the respective transmission / reception area. A shopping cart that receives a telegram sent from an access point measures the RSSI value with which the telegram is received and compares the measured value with the value sent in the telegram during the reception of the telegram. Only when the measured RSSI value reaches or exceeds the transmitted RSSI value, the received telegram is further processed and contained commands are executed. Otherwise the telegram is rejected. By assigning a fixed RSSI value to each transmission-receiving region, a plurality of transmission-reception regions of different sizes can be defined in a simple manner. However, the size of a single transmission / reception area can not be changed flexibly during operation.

Object of the invention

0007It is therefore an object of the invention to specify an operating method, a communication system and a communication terminal, in particular for communication in danger sign systems which do not have the disadvantages of the prior art, or at least defuse them, and with which the receiving range is flexibly adapted to different circumstances Can

Description of the invention

0008The solution of the object is carried out according to the features of the claims and is described in more detail below.

0009In a method according to the invention for operating a communication system, a limit value for the reception strength of a receiver in a telegram to be transmitted is provided for controlling the communication range. For this purpose, a transmitting system subscriber selects, for example, a smoke alarm detector, depending on its operating mode or the type of the receiving device, a limit value and, for example, inserts it into the header of a telegram to be sent. Of the

0010Limit value can be provided in the form of a reception field strength value (RSSI) or also only as a relative value from a relative scale of, for example, 0-10. A low limit value can be selected, for example, during an installation mode, whereas an alarm may even select the maximum possible value. However, it is also conceivable to generally set a low value even after an installation in order not to interfere with neighboring systems which have the same address range. As soon as the telegram has been completed and the limit value is inserted, the telegram is sent. All receivers within the physical range can receive the transmitted telegram. When receiving a telegram, the receivers simultaneously determine the receive strength with which the telegram is received. You can do this using, for example, an RSSI (Received Signal Strength Indication) function built into most radio chips. Even during the reception or shortly thereafter, the limit value for the reception strength is extracted from the telegram and compared with the reception strength during the reception. If this result shows that the measured reception strength falls below the limit, the telegram is discarded, or the reception still running is interrupted. Before comparing the reception strength with the limit value, a comparison of the receiver's own address with the address of the receiver to which the telegram may be directed may also be performed. If it is already established here that the addresses do not match, the comparison of the received strength with the limit value may be omitted since the telegram is rejected anyway. Preferably, the limit value for the received strength is to be transmitted in the same telegram with the reception strength of which the limit value is compared.

0011However, it is also conceivable that the limit value for the reception strength and the remaining data to be transmitted are divided into two or more telegrams. It is therefore particularly preferable to transmit and receive the limit value within the same telegram group, for whose telegrams the limit value applies. For example, the limit value for a reception field strength which applies to the following or a series of subsequent telegrams could be sent in a telegram. The telegram, which contains the reception threshold value for subsequent telegrams, is preferably transmitted with a higher transmission power and / or redundant, possibly even on different channels, and / or must be acknowledged by the receiver only before the subsequent telegrams are sent.

0012The method for operating a communication system regulates, in particular, the range of the communication and thus also represents a method for communicating. In a preferred embodiment of the invention, the communication system is formed by a danger message system. The invention therefore also relates to a method for communicating in a hazard message system. Such a hazard warning system often consists of at least one device, such as a danger reporting center, for receiving messages and from detectors with sensors for hazard characteristics such as smoke, wherein the detectors have at least one transmitter for sending alarms or status messages. A preferred type of dangers system is formed from a plurality of mutually interlinked hazard detectors, wherein each hazard detector is equipped, in addition to sensors and transmitters, with receivers and alarming and indicating means. In this method as well, a system subscriber, in particular a hazard detector, provides a limit value for a reception strength in a telegram to be sent. Subsequently, the telegram is sent and can be received by a second system subscriber, in particular a hazard detector. During the reception of the telegram, the reception strength is determined, for example, as an RSSI value and compared with the limit value from a previously received telegram, but preferably with the limit value received from the same telegram. If, in this comparison, it is determined that the reception strength is below the limit value, then the telegram is rejected.

0013The invention also relates to a communication system with at least one sending system subscriber, which is set up in particular for sending hazard messages, and with at least one receiving system subscriber, which is in particular configured to receive hazard messages. The transmitting system subscriber contains a first range-wide control, which provides the receiving system subscriber with a limit value for the reception strength in a telegram. The receiving system subscriber contains a second range-wide control, which comprises a measuring device for the reception strength of the received telegrams and a comparison device. The comparison device is configured to compare the received strength measured on reception of a telegram with the limit value which was provided by the sending system subscriber in a previously transmitted telegram, but preferably in the same telegram. The second range control is also configured to reject the received telegram if the measured reception strength falls below the limit value. In this case, a transmitting system subscriber can also receive corresponding devices for receiving and a receiving system subscriber can also contain the corresponding devices for transmission.

0014In a preferred embodiment of the communication system according to the invention, the communication system is formed by a dangers system in which the system subscribers, in particular, communicate danger messages among one another, for example, to exchange status and alarm messages among one another and finally to indicate system users. Such a hazard warning system consists of at least two mutually interlinked hazard detectors, which are in particular configured for detecting and reporting smoke, temperature, fire and / or gases. Each of these hazard detectors includes a transmitter and a receiver and a first and second range control. The first range control is set up to provide a limit value for a received strength in a telegram to be sent. The second range control comprises a first measuring device for the reception strength of the received telegrams and a comparison device. The comparison device is configured to compare the received strength measured on reception of a telegram with the limit value provided by the first range control of the sending danger indicator in a previously transmitted limit which is preferably provided in the same telegram. The second range control is configured to reject the received telegram if the measured reception strength falls below the limit value.

0015Finally, the invention relates to a communication terminal, which in a preferred embodiment is designed as a hazard detector with one or more sensors. In the embodiment as a hazard detector, the sensors are configured, in particular, for recognizing hazard characteristics such as smoke, temperature, fire and / or gas. The communication terminal according to the invention has a transmitter, a receiver and a control device, as well as a first and a second range-wide control. The first range control is set up to provide a limit value for a received strength in a telegram to be sent. The second range control comprises a measuring device for the reception strength of received telegrams and a comparison device. The comparison device is again set up to compare the received strength measured on reception of a telegram with the limit value provided by the first range control of a sending danger indicator in a previously transmitted telegram but preferably in the same telegram. The second range control or the control device is configured to reject the received telegram if the measured reception strength falls below the limit value.

Brief Description of the Drawings

0016The single FIGURE shows a communication system according to the invention with two communication terminals according to the invention which are designed as a hazard warning alarm.

FIG

0017The invention is explained in more detail below with reference to the single drawing. This shows, by way of example, a communication system (1) in the form of a hazard warning system (1), which is illustrated here by way of example with several hazard warning alarms (2). Alternatively, the system could also consist of a danger center (possibly 14) with one or more satellites such as hazard detectors (2). The danger warning devices (2) have a control unit (9) which controls and coordinates environmental measurements by means of the sensors (10) and the communication with other hazard warning devices. The control unit (9) also takes over the evaluation of the signals from the sensors (10). The hazard warning devices (2) also comprise display and alarming means (13) with which states, for example, faults such as a too low battery of the detectors (2) and alarms can be displayed. In this case, a hazard warning device (2) can display both its own states and alarms, as well as those of other hazard warning devices (2). For this purpose, a hazard warning device (2) contains at least one receiver (3) with which it can receive corresponding information from other hazard warning devices (2). A hazard warning device (2) also contains a transmitter (4) for sending status and alarm information. According to the invention, a first range control (5) is assigned to the transmitter (4). The first range control (5) inserts a limit value for the reception strength, which is selected at the time of reception, into selected telegrams, which are sent by the hazard warning alarm (2) to other hazard warning alarms (2) or, if appropriate, to a control center Of the telegram is evaluated by a hazard warning device (2) or, as the case may be, a control center. The limit value is preferably inserted into the header of a telegram. In order to receive messages from other hazard warning devices (2), a danger warning device (2) according to the invention also contains a receiver (3). A second range control (6) is assigned to the receiver (3). It is shown in the FIGURE that the second range control (6) comprises a measuring device (7) for the reception strength with which a telegram is received and a comparison device (8). In practice, the measuring device (7) for the reception strength will usually be a part of the receiver (3), which provides the reception strength of the second range control (6) eg in the form of an RSSI signal or value. Therefore, the logical as well as the physical allocation is shown here. The comparison device (8) compares the measured received strength with the limit value previously extracted from a telegram, whereby the limit value is extracted from a telegram sent before, but preferably from the same telegram. If, in this comparison, it is determined that the measured reception strength falls below the limit value, the received telegram is rejected. In the event that the reception of the telegram is still in progress, the telegram can then be terminated immediately. The rejection of the telegram can be effected in that the second range control (6) does not forward the telegram to the control unit (9), or outputs a signal to the control unit (9) which indicates to the control unit (9) Received telegram is not evaluated but discarded.

0018The selection of the reception strength limit values ​​by the first range control (5) is based on different criteria. The first range control (5) can, for example, select a very low limit value during an installation mode, which can be set in the operating mode Further operation is always exceeded. In this case, an adequate signal-to-noise ratio is maintained even in the case of subsequent changes in the transmission characteristics. In addition, it is also conceivable to provide a mute switching command with different ranges in the case of an alarm, which is reflected by all the detectors (2) in the system (1) when the danger warning alarms (2) are interconnected. If, for example, a mute-switching command is sent by a hazard warning device (2) which has not detected an alarm itself, then a low limit value could be provided in the telegram containing the mute-switching command, whereupon only detectors (2) Close this detector (2) to stop the alarm. If, however, the mute switch command is sent by the detector (2), which itself has detected an alarm, a high limit value can be selected so that all other detectors (2) in the system (1) terminate the alarm. It is also conceivable to set a low limit value for all detectors (2) even in the normal operating mode in order not to disturb neighboring systems (1) of the same type. By virtue of the physical range which is unchanged in contrast to the logical range, it is also conceivable to use a servicetool (14), for example, a laptop, a tablet PC or a smartphone with a suitable app which is used to monitor the states of the individual systems in a system (1 ) Hazard warning alarm (2) is to be used to receive and evaluate all telegrams from a larger distance without being restricted by a reduced transmission power. This service tool would simply ignore the limit value.