The invention relates to a method for transmitting data, in particular measurement data. Furthermore, the invention is directed towards a measuring appliance, such as a thermal energy meter, which uses the method.

It is known that in a low power wide area network low-energy appliances, such as measuring appliances, are connected to a server at least temporarily, wherein a protocol is configured so that a great range and a low energy consumption of the low-energy appliances can be achieved with low operating costs and a longer service-life in the case of battery-operated appliances.

The LoRa transmission method (long range or low radiation), for example, allows compensation for poor data connections between gateways and low-energy appliances. To this end, there are used (LoRa) spreading factors which determine how many symbols for coding (signal) data are used.

It is generally the case that the transmission duration of the data from the low-energy appliance to the gateway is extended and the range can be increased if the spreading factor is increased. At higher spreading factors, the low-energy appliances consume an identical transmission current in order to transmit the same quantity of data. However, overall a higher energy consumption results because the transmission duration becomes greater and therefore the transmission current flows for a longer time. As a result of the extended transmission time, the higher average transmission current consumption per time is reduced again. The extension of the transmission time is a counter-measure in order to reduce the average transmission current. In this case, it is disadvantageous that the data are transmitted less frequently and are accordingly available. The service-life or duration of use of a corresponding low-energy appliance is therefore shortened if a higher spreading factor is used, which is often a disadvantage.

Therefore, the object of the invention is to provide a method for transmitting data which is particularly energy-saving and current-saving and extremely resistant to disruption. A corresponding measuring appliance is further intended to be provided.

This object is achieved according to the invention by the features set out in the main claims 1 and 16. The notion of the invention involves prioritisation of the data to be transmitted in accordance with a present spreading factor. A selection decision is particularly reached as to what importance, relevance or the like the data to be transmitted, or partial quantities thereof, have. For example, the priorities are established one after the other. In accordance with the character of the data to be transmitted, they are subdivided into different priorities. The data are thus placed in a specific sequence.

In particular, in all spreading factors all desired data or data to be transmitted are transmitted. An anticipated service-life or duration of use of the measuring appliance is thus also achievable in the case of poor conditions or in the event of transmission disruptions occurring. The spreading factor changes, whereby the effective data rate also changes.

The spreading factor is particularly defined as a chip rate divided by a symbol rate. The chip rate is an internal processing speed or transmission rate/data rate, in particular after the spreading. As a result of higher spreading factors, a spreading increase is also increased so that the signal better stands out from a background noise (SNR). The chip rate is preferably always the same. Advantageously, a doubling of the ratio between the chip rate and the symbol rate is carried out with each increase to the next spreading factor. The spreading increase also becomes greater with a greater spreading factor. The higher a data rate is, the higher is a bit rate. For the same information length, therefore, the time period of the transmission at a higher data rate becomes shorter. When the data rate is increased, at the same time the sensitivity with respect to disruptions, distortion or the like also increases.

The selection of the data rate is carried out, for example, by a gateway by means of feedback to the measuring appliance. Alternatively, the measuring appliance has implemented at least one individual algorithm in order to adapt to a quality of the data transmission. Preferably, the selection of the data rate is carried out by a network server which advantageously communicates this selection to at least one gateway, which in turn preferably transmits this information to at least one measuring appliance.

The range or quality of the data transmission is, for example, highly dependent on the environment, obstacles, such as walls, or antennae/radio modules. The transmission is preferably carried out at intervals. Preferably, the data are subjected to the spreading before transmission. In particular, a time spreading is carried out. As a result of the time spreading, an energy consumption is distributed over a longer time period, which makes the transmission more robust with respect to short-term disruptions. A maximum flexibility of access is further ensured.

The method is capable of operating under variable environmental influences. It is also capable of operating with asymmetrical data rates. A data transmission, the parameters of which can be individually adapted, is made available. Different environmental conditions can be considered. Noise signals and other disruption signals can be suppressed. The system can react accordingly.

The data transmission is preferably carried out wirelessly, in particular by means of radio technology. The at least one data transmission unit accordingly operates advantageously with radio technology. The data to be transmitted are preferably converted into electromagnetic waves. Advantageously, a modulation technique is used. A protocol used is preferably completely bi-directional. For example, a test is carried out as to whether the data transmission is possible with the parameters established or transmitted.

The data to be transmitted are connected particularly with the measuring appliance and/or a measurement. They are, for example, measurement data, useful data, measuring appliance data or the like.

Preferably, a LoRa transmission is used. The LoRa network protocol is particularly configured for long ranges with low energy consumption. Advantageously, an end-to-end encryption is provided.

The measuring appliance is, for example, in the form of a heat meter or cold meter.

The at least one storage unit for electrical energy is, for example, in the form of a battery or accumulator.

Additional advantageous embodiments of the invention are set out in the dependent claims.

The method according to the subordinate claim 2 is particularly efficient. The defined data quantity corresponds, for example, to a number of bytes available.

The method according to the subordinate claim 3 has an extremely low energy requirement. The transmission time is in particular a sending time. In particular, the transmission time is a corresponding transmission duration or time period. The method according to the subordinate claim 4 again has a particularly low energy consumption. The transmission power is preferably a sending power. Advantageously, the transmission power is considered for the definition of the transmission time. Preferably, the necessary transmission power is calculated taking into account the peripheral conditions. A transmission at full sending power is preferably carried out, particularly at all times.

The method according to the subordinate claim 5 is extremely user-friendly. The data to be transmitted with the highest priority are preferably particularly important or relevant data, for example, the most important or most relevant data, such as energy, volume, appliance number, appliance time and/or error flags/error indicators.

The method according to the subordinate claim 6 is particularly user-friendly. The transmission time can, for example, be preset by a user or server.

According to the subordinate claim 7, the transmission time is increased or extended during the transmission of data with a lower priority, which leads to a higher electrical energy requirement. Per time (unit), however, the average energy requirement is reduced. Data with a lower priority are, for example, flow (rate), power, temperature supply and/or temperature return.

The method according to the subordinate claim 8 is extremely efficient.

The method according to the subordinate claim 9 is particularly efficient. Each data transmission has only an extremely low energy requirement.

In the method according to the subordinate claim 10, the data are transmitted in an extremely advantageous manner. At the lowest data rate, a transmission of data which have a lower priority in comparison with the highest priority is accordingly omitted.

In a method according to the subordinate claim 11, data of different priorities are transmitted. At the second-lowest data rate or higher, a transmission quality is better than at the lowest data rate.

In the method according to the subordinate claim 12, for example, data of a specific priority can be omitted.

The method according to the subordinate claim 13 also allows a transmission of data of different priorities.

The transmission power according to the subordinate claim 15 is preferably requested by a network server which preferably takes over the control in a network. The network server advantageously estimates how well data are received and, for example, transmits transmission parameters which are optimum for the measuring appliance so that the data can still be received reliably, but at the same time the consumption of the measuring appliance is reduced. The network server carries out the estimate, for example, with physical parameters which are measured by a gateway, such as reception strength, SNR (signal-to-noise ratio). The optimum transmission parameters are, for example, dependent on a data rate, reduction of a transmission power and/or channel list.

A number of preferred embodiments of the invention are described below by way of example with reference to the appended drawings, in which: Figure 1 shows a network architecture with measuring appliances which use a method according to the invention, and

Figure 2 shows a data transmission with different time periods.

Initially with reference to Figure 1, a network architecture which is illustrated therein in its entirety and which is in particular star-like comprises a plurality of terminals 1 which are in the form of LoRa terminals or LoRa measuring appliances here. Each LoRa terminal 1 has a measuring function and is preferably also capable of performing a calculation function. Furthermore, it has a radio module for converting the data, in particular measurement data, into a radio signal. The network is, for example, regional, national or global.

The LoRa terminals 1 are at least temporarily in radio connection with LoRa gateways 2 and are capable of communicating therewith accordingly. The LoRa terminals 1 can transmit data to the LoRa gateways 2 and advantageously also receive data. Each LoRa gateway 2 is preferably a hardware device which receives all the LoRa data/messages from the LoRa terminals 1. These messages are then preferably converted into an array of bytes.

The LoRa gateways 2 are capable of sending data, in particular data packets, to a LoRa network server 3 which takes over control in the network architecture. In comparison with the LoRa network server 3, the LoRa gateways 2 have only a limited calculation power.

The LoRa network server 3 is in turn capable of communicating with a connection server 4 which receives, for example, connection requests from the LoRa network server 3.

The LoRa network server 3 and the connection server 4 are capable of communicating with an application server 5, on which application programmes are installed or which is capable of carrying out application programmes.

The LoRa network server 3 is capable, for example, of forwarding messages/data to the correct application, selecting the best LoRa gateway 2 for messages/data, in particular downlink messages/data, removing duplicated messages/data if they have been received by several LoRa gateways 2, decrypting messages/data which are sent by LoRa terminals 1 and/or encrypting messages/data which are sent back to the LoRa terminals 1. A selection of the best LoRa gateways 2 is generally carried out on the basis of a link quality display. It is advantageous if an interface with the application server 5 is controlled by the LoRa network server 3.

The application server 5 is capable of communicating with a dashboard 6 which is capable of displaying or evaluating data of the LoRa terminals 1. The data of the LoRa terminals 1 are gathered in the dashboard 6.

The network is capable of automatically optimising the speed at which the LoRa terminals 1 transmit their data. An adaptive data rate can be achieved. The LoRa terminals 1 are capable, for example, of transmitting different information items/data. For the transmission, the data are subdivided into different priorities.

A table in which different data of the LoRa terminals 1 are contained by way of example with corresponding priority and size is set out below:

The highest priority is priority 1, the second-highest priority is priority 2. The priority 2 is lower in comparison with the priority 1. This applies similarly if a subdivision of the data to be transmitted into more than two priorities is carried out.

According to a first embodiment, a data transmission of a LoRa terminal 1 is carried out via LoRa in such a manner that the service-life thereof is complied with for transmission of all “Priority 1” data with a fixed transmission time T1 at a data rate DRO. If only the data rate DRO can be used, only the “Priority 1” data are transmitted by the LoRa terminal 1. A transmission of data with a lower priority, in this instance the “Priority 2” data, is consequently not carried out.

If the quality of the data transmission or radio connection is better, that is to say, instead of the data rate DRO the data rate DR1 or higher is used, both the “Priority 1” data and the “Priority 2” data are transmitted with the fixed transmission time T1 in the same data transmission. The extent of the “Priority 2” data is selected here so that, in the event of a change from the data rate DRO to the data rate DR1, the extent of the (signal) data does not more than double. At the data rate DR1, approximately twice as many data items can be transmitted in the same time as at the data rate DRO.

A second embodiment is described below. Reference may be made to the preceding explanations. According to the second embodiment, the data to be transmitted are subdivided into three different priorities. In this instance, the number of bytes in the “Priority 1” data and the “Priority 2” data and the “Priority 3” data is also not more than twice as great as the bytes in the “Priority 1” data and “Priority 2” data or not more than four times the “Priority 1” data. At the data rate DRO, the “Priority 1” data are transmitted. At the data rate DR1, the “Priority 1” data and “Priority 2” data are transmitted. At the data rate DR2 or better, the “Priority 1” data and “Priority 2” data and the “Priority 3” data are transmitted at the fixed transmission time Tl.

A third embodiment is described below. Reference may be made to the preceding explanations. In this case, this substantially involves a generalisation of the first and second embodiments. The data to be transmitted are subdivided into up to six different priorities. In this case, the rule is complied with, according to which per priority level more bytes do not become added than the sum of the bytes of all the lower priority levels together and/or the transmission duration does not become greater than for all the “Priority 1” data. The transmission is again carried out at the fixed transmission time Tl and the selection of the data by means of the priorities is determined by the data rate. For example, at the data rate DR4 all the data of the priorities 1 to 5 are transmitted. In this case, priority levels may also be omitted. A fourth embodiment is described below. Reference may be made to the preceding explanations. According to the fourth embodiment, the data transmission is configured in such a manner that the servicelife of the LoRa terminal 1 is complied with during the transmission of a number of (signal) bytes N at a fixed transmission time T1 at the data rate DRO. In this case, the number of (signal) bytes N is greater than the number P of the “Priority 1” data bytes, wherein N is selected so that (N - P) > a greatest data item from the other priorities.

For example, let N = 38. The data definition is preferably in the above table. Per transmission at the fixed transmission time T1 at the data rate DRO, therefore, all the “Priority 1” data and two data items from the priority 2 can alternately be transmitted. This is illustrated in Figure 2. Data according to positions 1 to 5 are transmitted at the transmission time Tl, while data according to positions 6 + 7 or positions 8 + 9 are transmitted at double the transmission time 2 x Tl, mutually offset by the transmission time Tl.

A fifth embodiment is described below. Reference may be made to the preceding explanations. This substantially involves a generalisation of the fourth embodiment. A dimensioning of the transmissible (signal) bytes NO to N4 is generally carried out per data rate DRO to DR4. Enough bytes are always free so that additional data bytes can be inserted from the subsequent priorities. For example, at the data rate DRO the “Priority 1” data are transmitted at the transmission time Tl, while the “Priority 2” data are transmitted, for example, alternately with the doubled transmission time 2 x T 1 and, for example, the “Priority 3” data are transmitted alternately with the four-fold transmission time 4 x T 1. This method can also be applied to the other data rates DR1 to DR4.

A sixth embodiment is described below. Reference may be made to the preceding explanations. The division of the data according to the above Table is again present. The data rate DRO is used for radio transmission. The LoRa terminal 1 evaluates the transmission power requested by the gateway 2. There is a connection between the transmission power of the LoRa terminal 1 and the consumption of the battery capacity of the LoRa terminal 1. At a lower transmission power, naturally less battery capacity is required so that at the data rate DRO “Priority 2” data can also be transmitted at the transmission time TL

A seventh embodiment is described below. Reference may be made to the preceding explanations. This is generally the generalisation of the sixth embodiment for any number of priorities of the data.

An eighth embodiment is described below. Reference may be made to the preceding explanations. This is a combination of the embodiments 1 to 5 and 6, 7. The transmission time Tl is increased per priority. Furthermore, the data selection from the priorities is controlled via the requested transmission power.