METHOD FOR WIRELESSLY SENDING AT LEAST ONE MESSAGE FROM A REPEATER TO A RECEIVER VIA A WIRELESS TRANSMISSION CHANNEL

Description

[0001] The invention relates to a method for wirelessly transmitting at least one message from a repeater to a receiver via a wireless transmission channel. Furthermore, the invention relates to a repeater with means for implementing the method, a system comprising the repeater, a computer program, and a computer-readable storage medium comprising the computer program.

[0002] Repeaters are used to increase the radio range of wireless message transmission between a meter and / or control unit in a building or multiple buildings and a receiver. These repeaters are typically installed at the edge of a developing radio cell for the meter and / or control unit, which is intended to transmit the messages wirelessly to the receiver using radio technology. Such repeaters receive the range at the edge of the radio cell and retransmit the message wirelessly to the receiver using the same radio technology. This can effectively increase the range of the meters and / or control units.

[0003] However, wireless communication is not an unlimited resource. Instead, wireless transmission channels based on a radio protocol stack with a given frequency range typically have only a limited utilization rate that they are permitted to use. The utilization rate, also known as the "duty cycle," is the ratio of transmission time—the time during which a device sends messages in the frequency range—to a given time period, such as one hour. Especially when using license-free frequency ranges, the permissible or maximum utilization rates per device are strictly limited and must not be exceeded to prevent the communication participants using the frequency range from completely occupying the frequency range, which can lead to collisions and message loss during message transmission.

[0004] As with all communications devices, a repeater, as a communications device in the aforementioned radio protocol stack with the specified frequency range, is therefore assumed to have a maximum utilization factor that must not be exceeded. The maximum utilization factor specifies a maximum transmission time of the repeater for continuous, predefined time periods. In the example of the predefined time periods of one hour, for example, the repeater can use a specific transmission time, for example, 3.6 seconds. This corresponds to a maximum utilization factor or duty cycle of 0.1%. In other words, the repeater and any other communications device may send messages over the wireless transmission channel with the radio protocol stack with the specified frequency range for a maximum of 0.1% of the predefined time period – in this example, one hour and thus 3.6 seconds.This predefined time period repeats or is continuous. This means that the repeater and all other communication devices communicating via the radio protocol stack with the specified frequency range are permitted to use the maximum transmission time, in this example, 3.6 seconds, for each new hour.

[0005] The state of the art in this area is US 2013 / 0237777 A1, which discloses a wireless network in which medical sensor data is transmitted via transceivers. Current information on the utilization level of the transmission frequencies corresponding to the maximum utilization level is determined, signaled, and used.

[0006] US 2016 / 0021433 A1 discloses relaying data for a wireless network of battery-powered sensors. Data is buffered in the relay, and the timing of data transmission is based on the relay's utilization limit.

[0007] In the prior art, it can happen that the repeater receives a number and / or size of messages in a predefined time period, for example, the example hour, which may in particular have been sent by several different meters and / or control units of one or more buildings, and that the maximum transmission time allocated to the repeater according to the maximum utilization level or duty cycle is not sufficient to immediately send or forward all of the received messages to the recipient within the predefined time period. In other words, the repeater requires more transmission time than it has available. It would have to violate the maximum utilization level or duty cycle as a condition, which is not permitted. Therefore, repeaters known from the prior art no longer forward messages if a current utilization level already corresponds to the maximum utilization level.This inevitably leads to a loss of messages and the information they contain, as they can no longer reach the recipient.

[0008] Accordingly, the object of the invention is to provide an improved method for wirelessly transmitting at least one message from a repeater to a receiver via a wireless transmission channel, which no longer has the disadvantages described above, in particular no longer leads to message and information loss and reduces the delayed transmission of time-critical information.

[0009] The above object is achieved by the subject matter of the patent claims. Further advantages and details of the invention emerge from the dependent claims, the description, and the drawings. Features and details disclosed in connection with the method according to the invention naturally also apply in connection with the repeater, system, computer program, and computer-readable storage medium according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0010] A first aspect is provided by a method for wirelessly transmitting at least one message from a repeater to a receiver via a wireless transmission channel based on a radio protocol stack. The radio protocol stack has a predetermined frequency range and a maximum utilization level of the frequency range by the repeater. The maximum utilization level specifies a maximum transmission time of the repeater for recurring and predefined time periods. The method comprises the following steps: Receiving the at least one message from at least one meter and / or at least one control unit of one or more buildings by the repeater, determining a current utilization level of the frequency range of the wireless transmission channel by the repeater, wherein the current utilization level indicates a previous transmission time of the repeater in a current one of the recurring and predefined time periods, and locally buffering the at least one received message on the repeater if the current utilization level has reached the maximum utilization level or the current utilization level would exceed the maximum utilization level by sending the at least one received message.

[0011] The received messages can be sent to the receiver via the wireless transmission channel when the repeater has available transmission time, i.e., when the current utilization level does not yet correspond to the maximum utilization level and does not exceed this level upon transmission of the message. As an alternative to local buffering, the method can therefore comprise a step of initiating transmission of the at least one received message from the repeater to the receiver, provided that the at least one received message can be sent to the receiver without the current utilization level becoming greater than the maximum utilization level, in particular provided that the current utilization level is less than the maximum utilization level. The invention starts at the point where the maximum utilization level is reached.For this purpose, it is proposed that in a predefined time period in which the current utilization level corresponds to the maximum utilization level or no further messages can be sent without exceeding the maximum utilization level, the received messages are buffered locally, i.e. on the repeater, so that these messages are not lost.

[0012] To determine whether the at least one received message can be sent to the recipient without the current utilization level becoming greater than or exceeding the maximum utilization level, a comparison of the current utilization level with the maximum utilization level can be carried out in one step of the method. In particular, a difference of any still available transmission time can be calculated. In other words, the previous transmission time can be subtracted from the maximum transmission time. This results in the still available transmission time within the predefined time period. For the next received message to be transmitted in the predefined time period, the necessary transmission time can be determined or estimated in an optional and further step of the method, in particular based on at least one parameter of the message, such as a size of the message.If the estimated required transmission time for the next message exceeds the available transmission time, it can be determined that at least one received message cannot be sent to the recipient without the current utilization level exceeding the maximum utilization level. Otherwise, the message can be initiated to be sent, as previously explained, because the required transmission time is less than the transmission time still available in the predefined time period.

[0013] The proposed method can be completely computer-implemented or some or all of the method steps can be executed and carried out by a computer.

[0014] In particular, multiple, especially different, messages can be received and sent. In other words, the method can be executed for multiple messages.

[0015] The method can of course comprise further method steps that precede receiving the at least one message and follow initiating the transmission of the at least one received message. Thus, the method can also comprise a step of transmitting the at least one message from the at least one meter and / or the at least one control unit of the one or more buildings to the repeater. The method can also comprise the step of transmitting the at least one received message from the repeater to the receiver, which can follow its initiation, which can be carried out by a computer, while the actual transmission can be carried out by a corresponding communication unit or transmission unit of the repeater, which establishes the wireless transmission channel or operates on the basis of the radio protocol stack with the predetermined frequency range.

[0016] It is provided that the method further comprises the step of initiating a transmission of the at least one received message that is temporarily stored locally on the repeater as soon as the current utilization level is below the maximum utilization level and the current utilization level would not exceed the maximum utilization level by sending the at least one received message. The transmission time can be determined as described above. The transmission of the message can accordingly be initiated in a further one of the repeating or continuous time periods after a previous orThe current time period in which the current utilization level already corresponds to the maximum utilization level or is at least already so high that no further message can be sent without exceeding the maximum utilization level has expired, because the new utilization level in the new time period is zero or no utilization has yet occurred. This ensures, on the one hand, that the cached messages can be received by the recipient and are not lost, and that they can be received by the recipient in a timely manner and without excessive delay.

[0017] Furthermore, it is provided that addresses of meters and / or control units associated with various received messages are compared with a predefined prioritization of various addresses of meters and / or control units. The transmission or buffering of the multiple received messages is then initiated in an order corresponding to the predefined prioritization. This means that the meters and / or control units that transmit messages to the repeater each have an address for the wireless message transmission used between the meters and / or control units and the repeater.For wireless message transmission between the meters and / or control units and the repeater, a wireless transmission channel based on a radio protocol stack with a specified frequency range can also be used. The radio protocol stack and the frequency range can be the same as that of the repeater. The address can be detected by the repeater to identify the meters and / or control units. Prioritization then specifies a sort of ranking in which the buffered messages are sent. Accordingly, in a predefined time period in which the current utilization rate is lower than the maximum utilization rate or there is still transmission time available for the repeater, those messages with a high priority can be sent first.Other messages with a lower priority can then be sent later, especially in a future predefined time period, if the sending time is limited.

[0018] The predefined prioritization is determined based on the frequency of receipt of messages associated with each address within a predetermined time period. In other words, the frequency of messages received by each counter and / or control unit can be determined. The frequency is the number of messages received per unit of time, for example, per day, per hour, or per predefined time period. Prioritization can then be performed for each counter and / or control unit, or for the addresses associated with it, such that addresses, counters, and / or control units with a high frequency or, in other words, frequency of messages are prioritized over addresses with a lower frequency or frequency, i.e., which are sent less frequently per unit of time.If, for example, a first counter and / or a first control unit with a first address sends a message every 15 minutes and a second counter and / or a second control unit with a second address sends a message every 300 minutes, the priority of the first address can be determined or specified to be higher than that of the second address. In the simplest case, the prioritization can be organized or designed as a table in which the addresses are ordered or numbered according to their priority. The buffered messages associated with the addresses can then be sent according to their order or numbering. In the given example of the two counters and / or control units, it can thus be ensured that the messages from the first address, which are sent with the significantly higher frequency orFrequency can reach the recipient faster than those from the second address, which, due to the low frequency, are less time-critical than those from the first address.

[0019] It can also be provided that an address of the at least one counter and / or the at least one control unit associated with the at least one received message is compared with a positive list of various addresses of counters and / or control units. Accordingly, initiating the transmission or locally caching the at least one received message can only occur if the address associated with the at least one received message is on the positive list. The repeater can then have a positive list (also referred to as a "white list"), which can be stored in particular on a storage medium of the repeater, with which it compares the address of the received message. If the address is present in the positive list, the repeater can send the message to the recipient or cache it locally, depending on the current load level.If the address is not in the whitelist, meaning it is unknown to the repeater, the message can be ignored, neither sent nor cached. This provides security against unknown or untrusted meters and / or control units. It also prevents messages from exhausting the repeater's available storage capacity and maximum transmission time, which, according to the whitelist, are not required or desired by the receiver operator.

[0020] Furthermore, it can be provided that the method additionally comprises the step of checking the occupancy of the wireless transmission channel over which the at least one message is sent, before initiating transmission of the at least one received message. In particular, the check can determine whether the wireless transmission channel is free or occupied in the frequency range of the radio protocol stack. This can additionally prevent messages from being lost due to collisions with other messages in a busy transmission protocol, even when transmission time is available. The occupancy of the wireless transmission channel can be checked, for example, using the so-called Carrier Sense Multiple Access / Collision Avoidance method.

[0021] In this case, it can be provided that the at least one received message is only sent if the check shows that the wireless transmission channel is not occupied. Otherwise, if the message has not yet been buffered, the at least one received message can be buffered locally on the repeater. However, if the message has already been buffered, local buffering can occur as described herein, even if transmission time is available.

[0022] In particular, it can be provided that the at least one message contains at least one meter reading. The meter reading is understood to be the measured value of the meter, in particular the consumption meter. In particular, the consumption of water, gas, heat, and cooling can be measured. Such consumption is recorded in one or more buildings, for example, building complexes.

[0023] In this respect, it can be specifically provided that the at least one meter or consumption meter is at least one from the group of gas meters, water meters, heat meters, and / or cooling meters. In particular, these can be electronic meters or at least meters equipped with electronic reading devices and wireless communication devices. If there are multiple meters from which messages are received by the repeater, they can each be the same or different meter types from this group.

[0024] Alternatively or additionally, it is possible for the at least one message to contain at least one control value or, in other words, a control specification from the at least one control unit. This can be used in various applications in buildings, such as a heating control unit, alarm system, or the like, which are considered as special embodiments of control units in one or more buildings.

[0025] In particular, the at least one meter can be a self-sufficient, particularly battery-operated meter. Self-sufficient operation means that a self-sufficient energy or power supply is used, meaning that the meter is not connected to a power grid. An example of this is a battery-operated meter, or in other words, a battery-operated meter. Unlike electricity meters that are typically connected to the power grid and supplied with power via it, self-sufficient electricity meters cannot continuously send messages because they only have a limited amount of energy available to them.

[0026] It can also be provided that the receiver is a central communications unit of an intelligent metering system. The intelligent metering system is also known as a smart meter gateway. Electronic meters can be connected to the smart meter gateway via a local area network (LMN). The meter readings recorded by the electronic meters for water, gas, heat, and / or cooling, or similar, can then be sent to the network operator via a wide area network (WAN) of the intelligent metering system.

[0027] The radio protocol stack can also be a wireless M-Bus radio protocol stack. The wireless M-Bus radio protocol stack has become particularly popular for utility meters in buildings.

[0028] Furthermore, it may be stipulated that the frequency range is a license-free frequency range. These frequency ranges, also known as ISM bands (ISM stands for "Industrial, Scientific and Medical Band"), can be used free of charge. In return, they are subject to the previously explained restriction regarding the maximum utilization rate or duty cycle.

[0029] The frequency range can be below 1,000 MHz, for example, 868 MHz. This comparatively low frequency is advantageously used for the transmission of (consumption) meter readings, as free-space attenuation is low, thus allowing a long range to be achieved. However, other frequency ranges are also possible, for example, the frequency of 433 MHz, which can be used preferably for control units such as those described here.

[0030] According to a second aspect of the invention, the object mentioned at the outset is achieved by a repeater having means for carrying out the method according to one of claims 1-9.

[0031] The means may, in particular, comprise a computer or a CPU, for example in the form of a microcontroller. Furthermore, the means may comprise a computer-readable data memory or a storage medium on which the received messages can be locally buffered. Furthermore, the repeater may comprise a communication means, in particular one or more antennas, which has a common receiving and transmitting unit or separate receiving and transmitting units, each for receiving the at least one message and for transmitting the at least one message.

[0032] According to a third aspect of the invention, the object mentioned at the outset is achieved by a system comprising a repeater according to the second aspect of the invention, at least one meter which is or can be connected to the repeater for communication purposes and / or a control unit which is or can be connected to the repeater for communication purposes in one or more buildings, and a receiver to which the repeater can send the at least one message via the wireless transmission channel.

[0033] As already explained, the receiver can in particular be a central communication unit of an intelligent measuring system.

[0034] According to a fourth aspect of the invention, the object mentioned at the outset is further achieved by a computer program comprising instructions which, when the program is executed by a computer, cause the computer to execute the method according to the first aspect of the invention.

[0035] Finally, according to a fifth aspect of the invention, the object mentioned at the outset is further achieved by the computer-readable storage medium on which the computer program according to the fourth aspect of the invention is stored.

[0036] The invention is explained in more detail below with reference to exemplary embodiments, based on the accompanying drawings. All features apparent from the claims, the description, or the figure, including structural details, may be essential to the invention both individually and in any combination. Figure 1 shows a schematic representation of a system according to an embodiment of the invention.

[0037] Elements with the same function and mode of action are Figure 1Each is provided with the same reference symbols. If an element with the same function and mode of operation is represented more than once, it is numbered consecutively, with the consecutive numbering separated from the reference symbol by a dot.

[0038] Figure 1 schematically shows a system 1 according to an embodiment of the invention. The system 1 comprises a plurality of meters 20.1, 20.2, 20.3 in the form of consumption meters, which can be from the group of gas meters, water meters, heat meters, and / or cooling meters. The meters 20.1, 20.2, 20.3 can be of different or the same meter type. Purely by way of example, it will be assumed below that the meter 20.1 is a water meter, the meter 20.2 is a heat meter, and the meter 20.3 is a gas meter. All meters 20.1, 20.2, 20.3 are operated autonomously, in particular battery-operated.

[0039] The meters 20.1, 20.2, 20.3 are located in a building 10, but can also be distributed across multiple buildings or a building complex, or the like. The type of building is irrelevant. Rather, what is crucial is that the meters 20.1, 20.2, 20.3 can be located in one building 10 or multiple buildings 10 to record meter readings of energy consumption, such as water consumption, heat consumption, cooling consumption, and / or gas consumption. The meters 20.1, 20.2, 20.3 can be located in the building 10 or buildings 10 themselves, or on the building 10 or buildings 10, i.e., in the immediate vicinity.

[0040] System 1 also includes a repeater 30 and an intelligent measuring system 41. These are also arranged in the building 10 in the present example, but can also be arranged in or on neighboring buildings 10 or simply in the immediate vicinity.

[0041] The repeater 30 comprises a computer 31, a data storage device 32, and a communication device 33. A computer program (not shown) is stored on the data storage device 32. The intelligent metering system 41 comprises a central communication unit 33 as a receiver 40, by means of which the meter readings contained in messages 3.1, 3.2, 3.3 from the meters 20.1, 20.2, 20.3 can be sent to a network operator 50 via a secure wide area network 4.

[0042] The repeater 30 is used to repeat the messages 3.1, 3.2, 3.3 with the meter readings contained therein, because the radio range of the wireless transmission or communication channels 2.1, 2.2, 2.3 at the installation location of the meters 20.1, 20.2, 20.3 does not reach the intelligent metering system 41 or its communication unit 40.

[0043] For the wireless transmission channels 2.1, 2.2, 2.3 between the meters 20.1, 20.2, 20.3 and the repeater 30 or its communication device 33, and for the wireless transmission channel 2.4 between the repeater 30 and the intelligent metering system 41, a wireless M-Bus radio protocol stack with a specified frequency range is used here as an example. The specified frequency range can, for example, be 868 MHz. This is a license-free frequency range. It is subject to a restriction regarding the so-called "duty cycle" and has a maximum utilization rate with regard to transmission time. The maximum utilization rate is defined by the ratio of a permissible transmission time to a specified time period, for example, one hour. The transmission time is the time during which the repeater 30 can transmit messages 3.1, 3.2, 3.3 in the frequency range of the wireless transmission channel 2.4 to the intelligent metering system 41.In other words, the maximum utilization rate determines how long repeater 30 may transmit messages 3.1, 3.2, 3.3, and 3.4 per specified time period in the frequency range of the wireless M-Bus radio protocol stack used. For ease of description, the maximum utilization rate is assumed to be 0.1%. This means that repeater 30 has a transmission time of 0.1% per recurring time period, which is chosen here purely as an example as one hour. Accordingly, repeater 30 may transmit for 3.6 seconds per hour, or has a permitted transmission time of 3.6 seconds per hour, to transmit messages 3.1, 3.2, and 3.3, which it receives from meters 20.1, 20.2, and 20.3, to intelligent metering system 41.

[0044] In a method according to an embodiment of the invention, it is now provided that the repeater 30 receives the messages 3.1, 3.2, 3.3, which is done by the communication means 33. The computer 31 of the repeater 30 then determines a current utilization level for the frequency range of the wireless transmission channel 2.4, i.e., the previous transmission time of the repeater 30 within the predefined time period of one hour. The computer 31 then compares the previous transmission time or the current utilization level with the maximum transmission time or the maximum utilization level in the current hour or time period. The computer 31 then initiates the transmission or forwarding of the received messages 3.1, 3.2, 3.3 if the maximum utilization level has not yet been determined. However, it can also be provided that the computer 31 determines the required transmission time for the respective messages 3.1, 3.2, 3.3 and sends the respective messages 3.1, 3.2, 3.3 are only sent via the wireless transmission channel 2.4 to the intelligent metering system 41 when sufficient transmission time is still available without exceeding the maximum transmission time. Otherwise, those messages 3.1, 3.2, 3.3 that cannot be sent without exceeding the maximum transmission time are buffered locally in the current time period. The buffered messages 3.1, 3.2, 3.3 can be sent at a later time period or hour when transmission time is available again or the current utilization level is so far below the maximum utilization level that the buffered messages 3.1, 3.2, 3.3 can be sent from the repeater 30 to the intelligent metering system 41 without exceeding the maximum utilization level.

[0045] The procedure is explained below using a concrete example and with reference to Fig. 1This example will be explained in more detail, assuming that the current broadcast time is 3.4 seconds and that a time period of one hour is considered, with 3.6 seconds of broadcast time available. The example figures, especially broadcast times, are purely fictitious and are chosen to facilitate understanding of the process.

[0046] First, message 3.1 arrives at repeater 30, containing a water meter reading from meter 20.1, which is configured as a water meter. The current utilization rate is then determined, which in this example is 3.4 seconds of previous transmission time out of 3.6 seconds of maximum transmission time in this hour. Computer 31 initiates the immediate transmission of message 3.1 from repeater 30 or via communication unit 33 to receiver 40. The new, current transmission time is now 3.4 + 0.1 = 3.5 seconds in the current hour.

[0047] The same process as with message 3.1 now occurs with message 3.2 with regard to the heat meter reading from meter 20.2, which is configured as a heat meter. Here, too, message 3.2 is immediately repeated or sent from repeater 30 to intelligent metering system 41. The new, current transmission time is now 3.5 + 0.1 = 3.6 seconds. The maximum utilization rate has thus been reached.

[0048] There is no more transmission time available for sending or forwarding message 3.1 because the maximum capacity has been reached. This message 3.3 is buffered. It is irrelevant whether messages 3.1, 3.2, and 3.3 are encrypted, which may or may not be the case, because messages 3.1, 3.2, and 3.3 are merely forwarded or buffered, not read by repeater 30.

[0049] At the beginning of the following hour or time period, the buffered message 3.3 can then be sent from the repeater 30 to the receiver 41 because the current utilization rate is then zero again or no transmission time of the maximum transmission time has yet been used. List of reference symbols

[0050] 1System 2Wireless transmission channel 3Message 4Wide area network 10Building 20Meter 30Repeater 31Computer 32Storage medium 33Wireless communication unit 40Receiver, central communication unit 41Intelligent metering system 50Network operator

Claims

1. A method of wirelessly transmitting at least one message (3) from a repeater (30) to a receiver (40) over a wireless transmission channel (2), the wireless transmission channel (2) being based on a radio protocol stack having a predetermined frequency range and a maximum utilization level of the frequency range by the repeater (30), the maximum utilization level specifying a maximum transmission time of the repeater (30) for repetitive and predefined duration time periods, the method comprising the following steps: - receiving at least one message (3) from at least one meter (20) and / or at least one control unit of one or more buildings (10) by the repeater (30), - determining a current utilization level of the frequency range of the wireless transmission channel (2) by the repeater (30), wherein the current utilization level indicates a previous transmission time of the repeater (30) in a current one of the repetitive and predefined time periods, and - local buffering of the at least one received message (3) on the repeater (30) if the current utilization level has reached the maximum utilization level or the current utilization level would exceed the maximum utilization level by transmitting the at least one received message (3), - initiating transmission of the at least one received message (3) temporarily stored locally on the repeater (30) as soon as the current utilization level is below the maximum utilization level and the current utilization level would not exceed the maximum utilization level by transmitting the at least one received message (3), wherein addresses of meters (20) and / or control units associated with different received messages (3) are compared with a predetermined prioritization of different addresses of meters (20) and / or control units, and causing transmission of the plurality of received messages (3) in an order following the predetermined prioritization, wherein the predetermined prioritization is determined based on a frequency of reception of the messages (3) associated with each address in a predetermined time period.

2. Method according to claim 1, wherein an address of the at least one meter (20) and / or the at least one control unit associated with the at least one received message (3) is compared with a positive list of different addresses of meters (20) and / or control units and the initiation of the transmission or the local buffering of the at least one received message (3) only takes place if the address associated with the at least one received message (3) is on the positive list.

3. Method according to any one of the preceding claims, wherein the method further comprises the step of checking an occupancy of the wireless transmission channel (2) over which the at least one message (3) is sent, before causing transmission of the at least one received message (3), wherein in particular transmission of the at least one received message (3) is initiated only if the checking shows that the wireless transmission channel (2) is not occupied and otherwise the at least one received message (3) is buffered locally on the repeater (30).

4. Method according to one of the preceding claims, wherein the at least one message (3) contains at least one meter reading.

5. Method according to one of the preceding claims, wherein the at least one meter (20) is at least one of the group of gas meters, water meters, heat meters and / or cooling meters.

6. Method according to one of the preceding claims, wherein the at least one meter (20) is an autonomously operated, in particular battery-operated, meter (20).

7. Method according to one of the preceding claims, wherein the receiver (40) is a central communication unit (40) of an intelligent measuring system (41).

8. Method according to any one of the preceding claims, wherein the radio protocol stack is a wireless M-Bus radio protocol stack.

9. Method according to one of the preceding claims, wherein the frequency range is a license-free frequency range and / or is below 1,000 MHz.

10. A repeater (30) comprising means for carrying out the method according to any one of the preceding claims.

11. System (1) with a repeater (30) according to claim 10, at least one meter (20) in communication with the repeater (30) and / or at least one control unit in one or more buildings (10) in communication with the repeater (30), and a receiver (40) to which the repeater (30) can send the at least one message (3) via the wireless transmission channel (2).

12. A computer program comprising instructions which, when the program is executed by a computer (31), the computer causes a repeater (30) to execute the method according to any one of claims 1 - 9.

13. A computer-readable storage medium (32) on which the computer program according to claim 12 is stored.