Field of the invention

[0001] The present invention relates to controlling the battery lifetime of battery- powered consumption meters that provide meter readings wirelessly.

Background of the invention

[0002] In the field of battery-powered consumption meters that are read wirelessly through radio communication, there is a challenge relating to areas where a large number of consumption meters are not experiencing the same radio coverage with respect to concentrators. A straightforward solution built into many radio transceivers is, that the consumption meters automatically adjust the transmitting power depending on the signal quality, so with obstacles or longer distance to a concentrator they transmit with higher power, and thereby consumes more power from their battery, than the consumption meters with shorter distance to a concentrator. With originally equal battery capacity, the different transmission power in turn means that the batteries of the farther consumption meters discharge faster than the batteries of the closer consumption meters and thereby need to be replaced earlier. While this would also seem straightforward to do, reality is that replacement of a few meters here and a few meters there at infrequent intervals over an extended time period of several months or even years, is actually less desirable in many real use-cases than simply replacing all the consumption meters in the area when the first one dies due to discharged battery. Either way, replacing all at once, with a majority of them still having years of battery life left, or replacing one at a time at infrequent intervals over a period of several years, it is undesirable to the system manager/owner.

[0003] Putting up more concentrators in the area to reduce the distance to the farthest consumption meters reduces the problem, but there will always be a difference in distance between the meters, and thereby a difference in battery lifetime, and the increased amount of concentrators adds to the cost and complexity. Requiring all meters to transmit with the same power, which then has to be the power of the worst located meter, causes all meters to discharge substantially equally and thereby makes the servicing simple, but poses also a waste of battery and the overall transmitted radio energy in the area may supersede regulation limits, as the meters are not intended to all operate at high power transmission. Finally, it is an option to employ different meters in the area, in particular with different battery capacity or different radio transceiver technologies, to try to match the battery lifetime of meters at different distances from the concentrators. However, this is a complicated solution to manage and service, and it is not always possible to know beforehand, which meter locations will require higher power, as also obstacles and interference may influence required transmission power in addition to distance.

[0004] A challenge in the prior art is, for the operators who have this desire, to achieve that the battery lifetime of consumption meters can be coordinated or at least controlled within a group of consumption meters with less disadvantages than known solutions causes. Summary of the invention

[0005] The inventors have identified the above-mentioned problems and challenges related to controlling the battery lifetime within a group of consumption meters, and subsequently made the below-described invention by which the average power consumption may advantageously be controlled, which in effect may control the battery lifetime, and by which the average power consumption may be controlled even in accordance with a reference power consumption, which may thereby provide possibility for aiming at a predetermined battery lifetime determined by the reference power consumption.

[0006] In an aspect, the invention relates to a consumption meter arranged to measure a value, such as accumulated volume, relating to a fluid flowing in a connected fluid pipe system. The consumption meter is arranged to perform wireless communication of a data package relating to said value. The consumption meter comprises transmission quality parameters and information quantity parameters for controlling said wireless communication. The consumption meter is arranged to control said transmission quality parameters to achieve said wireless communication. The consumption meter is powered by a battery and comprises a reference power consumption. The consumption meter is arranged to control said information quantity parameters to control an average power consumption of said consumption meter in accordance with said reference power consumption.

[0007] According to the invention, the consumption meter is thereby advantageously controlling its average power consumption, which in effect controls its battery lifetime, as the battery has a finite capacity.

[0008] Further, the present invention provides for controlling the average power consumption even in accordance with a reference power consumption, thereby providing possibility for aiming at a predetermined battery lifetime determined by the reference power consumption.

[0009] In other words, the reference power consumption together with the battery capacity determines the battery lifetime of the consumption meter, as long as the average power consumption is controlled to be substantially equal to the reference power consumption, at least on average, or at least within a goal tolerance thereof defining an acceptable uncertainty of battery lifetime.

[0010] The control of average power consumption is achieved through enabling control of two main contributors to determining power consumption, namely the transmission quality parameters and the information quantity parameters. As the consumption meter is required to communicate the measured values, the free control of transmission quality parameters may under some conditions be restricted, for example where location and/or obstacles forces the consumption meter to transmit at highest transmission power setting, or using an extensive error correction method or a high degree of repetition of data packets, all of which would increase power consumption. However, the information quantity parameters are often freely controllable, at least to a larger extent, e.g. by reducing the number of data packages communicated, reducing the amount of non-essential information communicated, etc., all of which reduces power consumption, and may therefore according to the invention, be used to counteract the power consumption increase caused by the transmission quality parameters.

[0011] The present invention thereby discloses a consumption meter having a balancing mechanism between transmission quality parameters, which is to some extent decided by the circumstances, and information quantity parameters, which to a large extent can be adjusted for the purpose of achieving a predetermined power consumption by the consumption meter.

[0012] A possible advantage of the present invention is that the consumption meter can aim for a predetermined level of power consumption, i.e. a reference power consumption, and thereby facilitate a predictable battery lifetime to the extent that battery capacity can be known. This feature also provides the consumption meter with a technical solution to actually meet a battery lifetime expectation by the user, e.g. based on promises in the data sheet or by marketing materials, e.g. a statement promising 7 or 10 or 12 years battery lifetime.

[0013] Another possible advantage of the present invention is, that even when large variations in transmission quality parameters are necessary between consumption meters scattered over an area due to variations in communication distance and obstacle conditions, and thereby variations in transmission power etc., such variations can be reduced or eliminated by allowing a control of consumption meter power consumption to achieve a common level of power consumption among all the consumption meters in the area, i.e. a reference power consumption. When all the consumption meters have identical estimated remaining battery capacity, which is usually the case for new consumption meters of the same type, the commonly controlled power consumption results in all the consumption meters having identical battery lifetime. By coordinating several new consumption meters to have the same reference power consumption, e.g. selected to allow for 7 years of battery lifetime, and being equipped with the technology of the present invention to control their individual average power consumption in accordance therewith, all the consumption meters in the area may achieve equal or at least similar battery lifetimes, making them all due for replacement at about the same time. [0014] A further possible advantage of the present invention is, that if or when the transmission conditions change over time, e.g. because obstacles are introduced or removed, like the rising of a new, tall concrete building in the transmission path, which requires change of transmission quality parameters, the expected battery lifetime may be preserved by proper counter-balancing of the information quantity parameters according to the invention, to maintain the same average power consumption as before, in accordance with the reference power consumption.

[0015] Yet a further possible advantage of the present invention is, that if the control logic of a consumption meter at some point estimates that the remaining battery capacity is less than expected, e.g. due to variations in batteries, bad conditions over time, e.g. prolonged exposure to low temperatures, etc., the originally decided battery lifetime may be maintained by reducing the reference power consumption appropriately, and thereby cause the future controlling of the information quantity parameters to target the new reference power consumption. Similarly, if the user, e.g. a drinking water utility company, of a group of consumption meters after a number of years wishes to prolong the lifetime of the already installed consumption meters, this may according to the invention simply be done by reducing the reference power consumption of the consumption meters, thereby causing all the consumption meters in the group to control the information quantity parameters in accordance with the new reference power consumption, thereby reducing their power consumption and prolonging the expected remaining battery lifetime.

[0016] In the present disclosure, a consumption meter is for example an ultrasonic water meter, or any other fluid metering device for measuring flow and/or volume of a fluid, such as water, such as cold water, hot water, central heating water, district heating water, etc. The measured value relating to the fluid may represent current flow rate, average flow rate, accumulated volume, fluid temperature, etc.

[0017] According to the present disclosure, the consumption meter is battery driven as it comprises a battery, such as an alkaline battery or a lithium battery, such as an Li SOCb battery, or any other kind of electricity storage. [0018] Further, the consumption meter is in the present disclosure configured to communicate by wireless communication, e.g. for transmitting measured values relating to the fluid. The wireless communication is preferably conducted by radio technology, such as proprietary, open or standardized narrow-band or spread spectrum radio technologies, for example using ISM-bands, e.g. the 433 MHz band, 868 MHz, 915 MHz band or 2.4 GHz band, such as technologies like Open Metering System OMS, Wireless M-Bus (EN13757), LPWAN, NB-IoT (3 GPP Release 13), LoRaWAN ^® , IEEE 802.11 (Wi-Fi ^® ), IEEE 802.11 ah (Wi-Fi HaLow™), IEEE 802.15.4 (ZigBee ^® ), etc., or any other suitable radio communication technology for wireless consumption meters, such as smart meters, automatic meter reading AMR enabled meters, advanced metering infrastructure AMI meters, e.g. radio technologies for remote meter reading, as know by the skilled person within the field of battery- powered wireless water meters.

[0019] The wireless communication is according to the present disclosure arranged to communicate a data package related to the measured value, to a fixed or mobile data collector of a meter reading system, sometimes referred to as a concentrator. The data package may for example include the measured value, or at least a representation of it, preferably together with other data such as a time indication regarding the time of measurement of the measured value, an identifier for the consumption meter, other fluid-related data, such as several measurement values, temperatures, etc., status information e.g. regarding battery state, environment, e.g. regarding temperatures. Several data packages related to the same measure value and/or the other data may be necessary, depending on the communication technology chosen.

[0020] The wireless communication is said to be achieved in accordance with the present disclosure, when the data package and thereby the included measured value related to the fluid, has been received in an acceptable quality by a receiver, such as a data collector.

[0021] Transmission quality parameters are according to the present disclosure controlled in order to achieve the wireless communication. Depending on the reason that wireless communication is challenged for a specific consumption meter in a specific scenario, different types of transmission quality parameters may be more or less efficient in achieving reliable wireless communication. Such reasons may for example be longer than average range between consumption meter and receiver, e.g. consumption meters at the outskirts of the covered area, obstacles of different material affecting the wireless communication differently, interference and noise from the vast number of other wireless devices found in many places especially urban areas and often using the same radio frequency bands, etc. Further, the reasons for a challenging wireless communication is often a combination of several of these reasons, as a challenging range or obstacle, for example, weakening the transmission quality also increases the susceptibility to interference and other disturbances.

[0022] Transmission quality parameters may for example include transmission strength which can be increased until a reliable wireless communication is achieved and thereby affects transmission quality. Another transmission quality parameter may for example be data rate, which can be decreased until a reliable wireless communication is achieved, as slower transmission of a radio data package generally increases the quality of the transmission in terms of reliability. Yet other transmission quality parameters may relate to the degree and type of error correction applied, modulation type, whether to automatically repeat all transmissions, etc.

[0023] The skilled person within the field of wireless communication is well aware of different challenges to the transmission quality, and knows various parameters to adjust, some to increase, others to reduce, or introduce, in order to improve the signal quality. Such parameters are referred to as transmission quality parameters in the present disclosure.

[0024] The transmission quality parameters only affect the transmission quality, not the effective amount of usable data that is being delivered. For example, when a transmission quality parameter regarding data rate is being decreased in order to ensure signal quality and reliable receipt, it only means the transmission takes longer, not that less data are sent. And for example, when a transmission quality parameter regarding package repetition is introduced so each package is sent several times to increase the chance of receiving each package at least once, the amount of transmission is multiplied the same several times, but only the same amount of useful data are sent in total, because most of the transmitted data is redundant.

[0025] The information quantity parameters, on the other hand, according to the present disclosure relates to parameters which control the total amount of useful data being transmitted via the wireless communication. In this context, quantity refers to the quantity of usable data that is actually transmitted, for example the number of fluid measurements that should be sent per day, the precision of measurements values to include in transmissions, the possible use of destructive data compression or reduction, etc. [0026] The information quantity parameters are thereby opposed to the transmission quality parameters which for example repeats the same data or sends error correction information relating to transmitted data, instead of controlling the quantity of actual data. Put simpler, as example, the relationship between information quantity parameters and transmission quality parameters may be compared to the relationship between quantity and range.

[0027] By controlling the transmission quality parameters, the consumption meter is able to control the range for the communication, whether it is necessary due to extended actual geographical range, due to obstacles such as concrete buildings, due to bad wireless conditions such as interference or other noise, etc. [0028] By controlling the information quantity parameters, the consumption meter is able to increase or reduce the amount of actual usable data transmitted, for example to avoid or reduce the transmitting of non-essential measurements, status information, auxiliary data, etc.

[0029] According to the invention, the consumption meter controls the transmission quality parameters to ensure communication of data packages works. This influences the power consumption of the consumption meter, as many of the transmission quality parameters causes a higher power consumption to increase transmission quality. A direct example is the transmission quality parameters of increasing transmission strength, which naturally increase power consumption. But also the prolonged transmission times required when the data rate is decreased or error correction added, or the additional transmissions performed when package repetitions are introduced, causes a higher power consumption, as one significant factor for power consumption in a consumption meter, is the amount of time the radio transmitter is active.

[0030] The average power consumption of a consumption meter is, according to the present disclosure, referring to an average over a reasonable time causing the average power consumption to be substantially constant with unchanging parameters. The average power consumption preferably refers to the power consumption of the entire consumption meter, i.e. the power consumption from the included battery, as the power consumption of only the communicating unit may be difficult to isolate, and some of the information quantity parameters also influences the power consumption of other units of the consumption meter, e.g. the measurement unit. Further, when considering battery life time, the entire power consumption is relevant.

[0031] The power consumption related to fluid measurements in the consumption meter is pulsing in sync with the measurement interval, but an average over longer time than several measurement periods will determine a substantially constant power consumption related to measurements, as long as no communication is taking place.

[0032] The power consumption related to wireless communication is pulsing in sync with the transmission interval, but an average over longer time than several transmission periods will determine a substantially constant power consumption related to communication, as long as no measurements are made.

[0033] Thereby, an average over longer time than several of the longest periods among the measurement intervals and the communications intervals, provides a substantially constant average power consumption of the consumption meter, as long as none of the transmission quality parameters or information quantity parameters are changed. The longest period will typically be the communication interval, and thereby an average over several communication periods, e.g. considering a running average with a time window of several communication periods, will be sufficient to determine an average power consumption. For example, a consumption meter may be measuring fluid values, e.g. accumulated fluid volume, every two seconds, and may be transmitting the measurements every 1 minute. In this case a measurement power consumption pulse happens every two seconds, always approximately the same amount, and likewise a transmission power consumption pulse happens every minute, also at approximately equal amounts each time. Considering the average power consumption over a 10 or 100 minutes window would provide a reasonably constant average power consumption. If the intervals were longer, the averaging window to consider would also have to be longer. For instance, transmitting every 10 minutes, every hour, or maybe only once per day, would require longer windows when considering average power consumption, such as for example 4 hours, a week, or maybe a month.

[0034] The average power consumption relates to a specific set of transmission quality parameters and information quantity parameters. If any of the transmission quality parameters or information quantity parameters are changed, the average power consumption will also change. According to the invention, as the transmission quality parameters have to be set with the primary goal of achieving communication of the data package, the consequent change in average power consumption can be compensated for by controlling the information quantity parameters.

[0035] According to the present disclosure, the average power consumption need not necessarily be measured by the consumption meter. The average power consumption resulting from various combinations of transmission quality parameters and information quantity parameters for a certain model of consumption meter may be measured by the vendor and the measured average power consumption values be stored as predetermined power consumptions in the consumption meter. The predetermined power consumptions may be stored as actual power consumption values for example in units of Watts [W], or may be classified or categorized into a discrete number of power consumption classes or categories, to make the device management simpler and to identify combinations of parameter values that actually lead to substantially same average power consumption. For example, a doubling of signal strength combined with only transmitting half as many data packages may lead to an average power consumption similar to the average power consumption of consumption meter before the change. From a power consumption perspective, any of these combinations would provide substantially the same battery life time, and can be considered same category or class of power consumption, whereas increasing signal strength alone would increase the power consumption category or class one or more levels, and decimating the number of transmissions alone would decrease the power consumption category or class.

[0036] In an embodiment each parameter may have a categorization or classification or weight assigned to its possible values, in order to be able to consider or compare the consequence for power consumption of changing to a certain value, without having to try it out and measure the result. For example, the signal strength transmission quality parameter may have its possible strength values categorized into intervals, each having a category number or weight reflecting the consequential impact on average power consumption. The same can be done for other transmission quality parameters and the information quantity parameters, for example assigning a power consumption category or weight to each possible value or bucket of values of data package interval. Then, when considering increasing the signal strength by, say, two power consumption categories or a power consumption weight of, say, 1.25, the consumption meter if aiming for a status quo in average power consumption, need to find another parameter, e.g. data package interval, which can be changed oppositely, say, two power consumption categories down, or, say, by a power consumption weight of 0.80.

[0037] In an embodiment of measuring average power consumption, the average power consumption may be measured once upon each change of parameter values, and considered constant as long as the parameter values are constant, or be measured at very long intervals, such as once each month or quarter of year. The average power consumption may also be measured frequently to achieve a continuous monitoring and regulation.

[0038] In the present disclosure, the reference power consumption refers to a reference power consumption of the consumption meter, defined and determined in the same way as the average power consumption to be comparable therewith, i.e. for example for the entire consumption meter, using the same units of measure or categories, etc. The reference power consumption may be determined as the average power consumption at default parameter values, for example best practice parameter values, or the parameters values that work for most consumption meters in a deployment area. The reference power consumption may preferably be set to reflect a desired battery life time, as the reference power consumption with efficient control of parameter values may be considered the lifetime-average power consumption of the consumption meter, and thereby directly determine the battery lifetime as the battery capacity divided by the reference power consumption. For example, if the operator wants a battery lifetime of, say, 10 years, and the battery capacity is, say, 1200 mAh @ 3.6 V, the reference power consumption should ideally be 1200 mAh * 3.6 V / (10 years * 365.2422 days * 24 hours), i.e. around 49.3 pW (around 0.05 mW) on average throughout the lifetime. The person skilled in the art of battery powered consumption meters is aware about this simplification being the ideal scenario, and knows how to adapt to real life devices, by taking into account battery performance reducing over time, self-discharge, impact from surroundings, e.g. low temperature environments, variations in real capacity compared to nominal battery capacity, allowing for reserve lifetime as a safety tolerance or to provide a time slot of several months or years for operator to decide a best time for replacing the lot of consumption meters, factoring in different profiles and challenges of different battery technologies, etc. etc. As the skilled person is aware of these challenges and knows how to manage them in practice, the simplified examples and calculations are used in the present disclosure to describe the invention and embodiments for the convenience of the readers, who can adjust themselves to the actual battery challenges relevant to their scenarios.

[0039] According to the present disclosure, the consumption meter controls the average power consumption in accordance with the reference power consumption. Depending on the tightness of the regulation and the several tolerances and uncertainties about batteries, the battery lifetime can thereby be controlled.

[0040] In an embodiment, the reference power consumption is set to achieve a desired battery lifetime from a certain battery capacity. Then the transmission quality parameters are selected to achieve communication of the meter readings, i.e. the main purpose of the consumption meter. By determining, by measurement or estimation, possibly indirectly by using categorized or weighted values, a resulting average power consumption and comparing this to the reference power consumption, the consumption meter may determine the degree of mismatch, and compensate by controlling the information quantity parameters accordingly. Thereby may be achieved an average power consumption that matches the reference power consumption, and the consumption meter may function for approximately the desired lifetime, depending on the correctness of assumptions and tolerances applied by the person skilled in battery powered consumption meters as mentioned above.

[0041] In an embodiment, the reference power consumption may be stored in the consumption meter as a model-specific reference, e.g. in accordance with nominal battery lifetime and nominal battery capacity. In an embodiment, the reference power consumption may be adjusted for a group of consumption meters, e.g. after installation of the group, to reflect the power consumption of the consumption meter consuming, e.g., least power, an average power, or the power consumption similar among the highest number of consumption meters to limit adjustments to the least number of consumption meters.

[0042] In an embodiment, at least one of said transmission quality parameters is selected from the list of: transmission power, data transmission rate, error correction type, modulation type and number of transmission repetitions.

[0043] These parameters are all parameters that affect the transmission quality, and depending on the conditions for wireless communication at a specific location, different of these parameters may have to be adjusted to achieve or improve the wireless communication. The parameter adjustments to make to compensate for a longer line-of-sight distance may for example be different from the parameters adjustments that best improve communication through obstacles of concrete or metal, which may again be different from the adjustments most promising for communication in areas with high degree of interference from other radio-based transceivers or general electromagnetic noise. The person skilled in the area of practical radio communication in urban areas knows the characteristics of the different parameters that affect transmission quality and what challenges they are each good for overcoming. Error correction type may refer to various techniques for making a signal more robust to partial corruption. Modulation type may refer to various modulation types of the radio signal which may have different advantages and disadvantages and respond differently to various kinds of obstacles and noise types. Transmission repetitions is a simple way to improve the chance of getting the signal through, by transmitting it several times an assuming that at least one of the times is successful.

[0044] In an embodiment, at least one of said information quantity parameters is selected from the list of: transmission interval, data package payload size, data reduction method, data compression algorithm, measuring interval and display sleep mode.

[0045] These parameters are all parameters that relate to the total amount of useful data being transmitted, i.e. the effective information quantity. As a general rule, varying the information quantity of transmissions also varies the power consumption of the transmissions, provided the transmission quality parameters are not changed. Hence, when targeting a reference power consumption, the information quantity parameters can according to the invention be used to compensate for necessary changes to the transmission quality parameters. Payload size may refer to the amount of data that is actually transmitted when disregarding the data that are used for the transmission itself, but has nothing to do with the metering or meter, and reduction of payload may thereby for example involve reducing the number of meter readings included, reducing the metadata for the reading such leaving out year from timestamps, leaving out battery information every second time, etc. Data reduction method may refer to algorithms to reduce the amount of data, and compression algorithm refers to various algorithms to compress the digital representation of data as known by the skilled person. Measuring interval may refer to the frequency of making measurements and thereby the number of readings that is made and stored and possibly transmitted, whereas transmission interval refers to how often data are transmitted, which may typically be more rare than the measuring interval. Display sleep mode may refer to various approaches to reduce the power consumption of the display, for example by dimming or turning of the display when no user action such as button presses is detected, or according to a schedule or other events.

[0046] In an embodiment, said information quantity parameters comprise transmission information quantity parameters, preferably selected from the list of: transmission interval, data package payload size, data reduction method and data compression algorithm.

[0047] The parameters affecting power consumption related to information quantity may be divided into those that are related to the information quantity being transmitted, and those that relate to other information quantities that consume power. The above- listed information quantity parameters affect the power consumption of the transmissions, for example by changing the number of data packages being sent through a period, e.g. changing from hourly updates to daily updates, the quantity of raw data being transmitted in each update, e.g. whether or not to include nice-to-have information such as status information and data resolution in addition to the need-to- have information which first of all includes the measurement value itself, etc.

[0048] In an embodiment, said information quantity parameters comprise local information quantity parameters, preferably selected from the list of: measuring interval and display sleep mode.

[0049] Information quantity parameters that affect other aspects of power consumption of the consumption meter than the transmission itself is here referred to as local information quantity parameters, and may for example relate to the information provided locally in a display of the consumption meter, or relate to how often the measurement process should be performed, which typically involves power consumption by digital and analog electronic circuitry.

[0050] In an embodiment, said control of said information quantity parameters to control said average power consumption comprises controlling said transmission information quantity parameters. [0051] In this embodiment, the balancing of power consumption between transmission quality and information quantity is at least involving the transmission related quantity parameters, to allow disregarding the variation in power consumption related to the mere measuring and possible displaying of values.

[0052] In an embodiment, at least one of said transmission quality parameters is transmission power and/or data transmission rate, and at least one of said information quantity parameters is transmission interval and/or data package payload size.

[0053] Thereby a particularly advantageous and useful combination of parameters is provided, which allows adjustment of transmission power and/or transmission rate to achieve the desired transmission quality, i.e. achieve successful wireless communication of the data packages, and balancing the power consumption by counter-adjusting the transmission interval and/or amount of data being sent. For example may an increase in transmission power that turns out to be necessary to communicate a longer distance be balanced by also increasing the delay between transmissions or simply sending less data, i.e. operating the transmitter for a shorter time. Correspondingly, where data transmission rate can be increased because of good signal conditions, the transmitter is on for shorter time for each transmission, which may allow sending more often or including more nice-to-have information, without consuming more power in total.

[0054] In an embodiment, said controlling said transmission quality parameters to achieve said wireless communication comprises increasing said transmission power and/or decreasing said data transmission rate, and said controlling said information quantity parameters to control said average power consumption comprises increasing said transmission interval and/or decreasing said data package payload size to counteract an increased power consumption caused by said increased transmission power and/or decreased transmission rate.

[0055] In an embodiment, predetermined parameter combinations of specific transmission quality parameters and specific information quantity parameters are each associated with a predetermined average power consumption, and wherein said controlling said average power consumption comprises selecting one of said predetermined parameter combinations of specific transmission quality parameters and specific information quantity parameters based on its predetermined average power consumption and said reference power consumption.

[0056] To simplify the selection of appropriate parameters, and reduce the effort needed to finding a suitable value for counter-balancing parameters, a table or similar containing predetermined, suitable combinations of values of transmission quality parameters and values of information quantity parameters may advantageously be predetermined and stored in the consumption meter. For example, combinations of different values of transmission power with different values of transmission intervals, and the average power consumption estimated or measured for each combination may be predetermined and stored. With respect to a particular reference power consumption, the consumption meter may choose between all predetermined combinations that are associated with an average power consumption corresponding t to the reference power consumption. The meter may then determine the transmission quality parameters appropriate for achieving the wireless communication, and among the predetermined parameter combinations find a combination associated with the desired power consumption and having the determined transmission quality parameters, and thereby look-up the corresponding information quantity parameters.

[0057] In an embodiment, said consumption meter comprises a plurality of predetermined parameter combinations of specific transmission quality parameters and specific information quantity parameters, and wherein predetermined average power consumptions associated with two or more of said plurality of predetermined parameter combinations deviates by less than 25%, such as less than 20%, such as less than 15% such as less than 10%.

[0058] Thereby the consumption meter has at least two different predetermined parameter combinations of parameters to choose from and still achieve substantially the same power consumption, at least within 25%. The different predetermined parameter combinations thus balanced with similar power consumption preferably offer a range of combinations from those that have transmission quality parameters requiring more power and thereby information quantity parameters requiring less power, to those that oppositely require less power for transmission for good conditions and thereby can spend more power on information quantity.

[0059] In an embodiment, predetermined power consumption classes or power consumption weights are assigned to specific transmission quality parameters and to specific information quantity parameters, and wherein said controlling said average power consumption comprises selecting one of said power consumption classes or power consumption weights for said transmission quality parameter and one of said power consumption classes or power consumption weights for said information quantity parameters based on said reference power consumption.

[0060] As an alternative to predetermining combinations of parameters with associated average power consumptions, it may be advantageous to classify the different parameters values according to how they affect the power consumption. For example, various possible levels of transmission power may be assigned to different power consumption classes. The same are various possible sizes of data packages. By performing an appropriate classification of the parameter values according to their impact on power consumption, the balancing of transmission quality parameters and information quantity parameters may be based on these power consumption classes. For example, if the transmission power needs to be changed to a value classified two classes higher to achieve wireless communication, one of the other parameters have to be changed two classes down. Or two different parameters can be changed one class down, each. Thereby the average power consumption may be maintained constant. Instead of classification into discrete classes, each parameter value may be assigned a power consumption weight indicating its impact on power consumption. When changing a parameter value to a different power consumption weight, another parameter value may for example be changed to the reciprocal consumption weight so that their product is 1, provided the weights are assigned around 1. Other weighting schemes may be applied, e.g. based on percentages. [0061] In an embodiment, said controlling said transmission quality parameters is based on operator input, such as manual setting or template setting of transmission quality parameters, to achieve said wireless communication.

[0062] According to this embodiment, an operator, e.g. a person installing and configuring the consumption meter or a building caretaker, may select and input appropriate transmission quality parameters such as e.g. transmission power, to achieve successful communication.

[0063] In an embodiment, said controlling said transmission quality parameters is based on an automatic algorithm, e.g. a trial-and-error algorithm, for setting transmission quality parameters, to achieve said wireless communication.

[0064] According to this embodiment, an automatic algorithm may select appropriate parameter values, e.g. by increasing transmission power or decreasing data rate until wireless communication is achieved, or employing error correction when the error rate is unacceptable.

[0065] In an embodiment, said consumption meter is arranged to update said transmission quality parameters, when said wireless communication fails, to achieve said wireless communication.

[0066] The initiation of an update of transmission quality parameters may for example be caused by the consumption meter not getting acknowledge messages or too often being requested to re-transmit data. In an embodiment, the data collector may request the meter to improve transmission quality, or a human operator may decide that an update is relevant.

[0067] In an embodiment, said consumption meter is arranged to update said information quantity parameters upon change of said reference power consumption or said transmission quality parameters.

[0068] In order for the settings of transmission quality parameters and information quantity parameters to cooperate in targeting a specific average power consumption, they should be balanced in the sense that if one setting is changed to, e.g., increase power consumption by a certain amount, another setting should be changed to, e.g., reduce power consumption by approximately the same amount. As the transmission quality parameters are preferably prioritized in order to achieve successful wireless communication, and advantageous embodiment comprises updating the information quantity parameters consequently whenever the transmission quality parameters change. Similarly, whenever the reference power consumption changes, the parameters should be changed to target the new reference power consumption, and this in practice means to maintain the transmission quality parameter as long as the wireless communication works, and preferably only adjust the information quantity parameters to target the new reference power consumption.

[0069] In an embodiment, said consumption meter is arranged to counter-balance said information quantity parameters upon change of said transmission quality parameters to maintain said average power consumption in accordance with said reference power consumption.

[0070] In an embodiment, said controlling said average power consumption in accordance with said reference power consumption comprises controlling said average power consumption to be within a predetermined goal tolerance of said reference power consumption.

[0071] According to the invention, when controlling the average power consumption in accordance with the reference power consumption, it means that parameters values are set so that the average power consumption approaches the reference power consumption. Preferably, a goal tolerance is predetermined to allow a minor deviance between the achieved average power consumption and the targeted reference power consumption. The goal tolerance allows some degree of freedom to the controller in setting the parameters. The goal tolerance on reference power consumption in practice defines an acceptable uncertainty of battery lifetime.

[0072] In an embodiment, said predetermined goal tolerance is not more than ±40%, such as not more than ±25%, such as not more than ±15%, preferably not more than ±10%, most preferably not more than ±5% of said reference power consumption. [0073] In an embodiment, said consumption meter is arranged to estimate a remaining battery lifetime of said battery as an estimated remaining battery capacity of said battery divided by said average power consumption.

[0074] In an embodiment, said consumption meter is arranged to estimate a remaining battery lifetime of said battery on the basis of an estimated remaining battery capacity of said battery and current settings of said transmission quality parameters and said information quantity parameters.

[0075] In an embodiment, said reference power consumption is determined on the basis of an estimated remaining battery capacity and a predetermined battery lifetime.

[0076] This embodiment is useful in several practical applications, where the provider or manager of a meter reading system specifies a desired lifetime rather than specific power consumption levels. The reference power consumption is in turn determined from the desired lifetime and the battery capacity. This embodiment may further adapt to changing wishes of the manager, in that the manager may change the expected remaining lifetime, for example to postpone the time where meters have to be replaced or have new batteries installed, and when changing the lifetime, an update of the reference power consumption may be made accordingly, and in turn cause an update of at least the information quantity parameters to accommodate the new, probably lower, reference power consumption.

[0077] In an embodiment, said consumption meter, e.g. an ultrasonic water meter, is a fluid metering device for measuring flow and/or volume of a fluid, such as water, such as cold water, hot water, central heating water, district heating water, etc.

[0078] In an embodiment, said measured value represents one or more of current flow rate, average flow rate, accumulated volume, fluid temperature, etc.

[0079] In an embodiment, said wireless communication is based on radio technology.

[0080] In an embodiment, said consumption meter is arranged to perform said wireless communication of said data package with a fixed or mobile data collector of a meter reading system, such as a concentrator. [0081] In an embodiment, said data package comprises said measured value or a representation of said measured value, and preferably further comprises other data such as a time indication regarding the time of measurement of the measured value, an identifier for the consumption meter, other fluid-related data, such as several measurement values, temperatures, etc., status information e.g. regarding battery state, environment, e.g. regarding temperatures.

[0082] In an embodiment, said wireless communication is bidirectional wireless communication.

[0083] Meter reading systems may be based on unidirectional or bidirectional radio communication between meters and data collectors. With unidirectional configurations, meter data can be collected, but neither acknowledgments, nor configuration or control data, can be transmitted to the meters by that communication link. Bidirectional communication allows the meter and collector to negotiate optimal transmission quality parameters, or at least enables the meter to know whether the data packages are being received, by exchange of acknowledgment messages. Further, bidirectional communication allows the collector or other unit, e.g. a backend system, in the meter reading system to upload updated configurations, firmware, etc., to the consumption meters. Such configurations may for example include settings of reference power consumption or even transmission quality parameters and information quantity parameters.

[0084] In an embodiment, said consumption meter is arranged to receive configuration data, such as predetermined battery lifetime or reference power consumption, from a data collector or from a backend system directly or via a data collector through said wireless communication.

[0085] In an embodiment, said average power consumption is an average over several transmission intervals, such as at least 3 transmission intervals, e.g. at least 10 transmission intervals, such as at least 100 transmission intervals.

[0086] As the instantaneous power consumption typically increase significantly, and significantly more than any other periodic power change, during wireless transmission, an averaging over several transmissions, i.e. including several periods without transmission and several periods with transmission, may provide a reliable and fairly constant average power consumption as long as the parameter values are maintained. The person skilled in the art of electric power metrics and evaluation knows several ways of determining an averaged power, including both the measuring part and the calculation part thereof, and knows advantages and disadvantages of various averaging methods. According to the present invention, the specific averaging method being applied is not relevant. The skilled person should aim at an averaging method yielding a substantial constant average over a time window containing several, for example 3- 300, transmission intervals, to be able to use the average value in a regulation loop where it is compared to the reference power consumption and adjusted by means of controlling the transmission quality parameters and information quantity parameters as described above. As these parameters are mostly discrete-valued parameters and changed in steps, or even only allowing two levels: on and off, and/or require confirmation of feasibility after each adjustment, such as successful wireless communication should be confirmed after each adjustment of transmission quality parameters, it is desirable to adjust these parameters as rarely as possible, and therefore not apply too short an average or too fast a regulation loop. On the other hand, the average should be fast enough to indicate changes reasonable soon after power- affecting parameters are changed, and/or the averaging be reset at each parameter adjustment.

[0087] In an embodiment, said average power consumption is an average over at least 10 minutes, such as at least 60 minutes, e.g. at least 24 hours, such as at least 7 days or a month.

[0088] In an embodiment, said controlling said average power consumption of said consumption meter is based on an estimated average power consumption based on measurements of current and/or voltage.

[0089] In an embodiment, said controlling said average power consumption of said consumption meter is based on an estimated average power consumption based on predetermined power consumptions of predetermined parameter combinations of specific transmission quality parameters and specific information quantity parameters.

[0090] Instead of measuring current and/or voltage to determine the power consumption, the different possible parameters values may be assigned to different levels of predetermined power consumption, thereby allowing an estimation of power consumption based on the parameter values. This also improves the controlling of parameters because the power consumption of different parameter combinations can be estimated in theory, before actually setting the values.

[0091] In an embodiment, said controlling said average power consumption of said consumption meter is based on predetermined power consumption classes or power consumption weights of predetermined specific transmission quality parameters and predetermined specific information quantity parameters.

[0092] In an embodiment, said consumption meter is arranged to estimate said average power consumption after a change of transmission quality parameters or information quantity parameters.

[0093] Preferably, the average power consumption is estimated either by measuring or by considering predetermined power consumption levels for the selected parameter values, each time parameter values are changed, in order to confirm that new values still allows targeting the predetermined reference power consumption. If not, the parameter value update should be cancelled, or other parameter values be updated oppositely to compensate for the change.

[0094] In an aspect, the invention relates to a meter reading system comprising a data collector and a plurality of consumption meters. Each consumption meter is arranged to measure a value, such as accumulated volume, relating to a fluid flowing in a connected fluid pipe system and to perform wireless communication to said data collector of a data package relating to said value. Each of said consumption meters comprises transmission quality parameters and information quantity parameters for controlling said wireless communication. Each of said consumption meters is arranged to control said transmission quality parameters to achieve said wireless communication with said data collector. Each of said consumption meters is powered by a battery. Each of said consumption meters comprises a reference power consumption determined on the basis of a predetermined battery lifetime common to said plurality of consumption meters. Each of said consumption meters is arranged to control said information quantity parameters to control an average power consumption of said consumption meter in accordance with said reference power consumption.

[0095] Everything described above in relation to consumption meters, measured values, data packages, wireless communication, transmission quality parameters, information quantity parameters and the controlling of them, as well as average power consumption and reference power consumption, battery capacity and lifetime, etc., also applies to this aspect of the invention.

[0096] In an embodiment, said consumption meters are the consumption meters according to any of the above disclosure.

[0097] In an embodiment, said consumption meters are distributed geospatially.

[0098] The invention is particularly advantageous when several consumption meters are distributed in an area, such as mainly horizontally distributed in a low-rise urban area or countryside, or vertically and possibly horizontally in a high-rise urban area or a single building, as the distribution will in almost all cases cause the consumption meters to operate under different conditions for wireless communication, for example in terms of different distances to the data collector, or different degrees of obstacles or noise between meters and data collectors.

[0099] In an embodiment, at least two of said consumption meters have different distances to said data collector.

[0100] In an embodiment, at least two of said consumption meters are located so they experience different conditions for wireless communication with said data collector.

[0101] In an embodiment, said data collector is a distributed data collector comprising separate data collection units geospatially distributed. [0102] In an embodiment, said meter reading system comprises a backend system communicatively coupled to said data collector and comprising a database for storing said measured values communicated to said data collector from said consumption meters.

[0103] The backend system may also take part in the configuration of the consumption meters, e.g. by setting the reference power consumption.

[0104] In an embodiment, said data collector forms part of said backend system.

[0105] In an embodiment, said backend system is located at a geospatially different location than said data collector.

[0106] In an embodiment, said data collector is a fixed or mobile data collector, such as a concentrator, and said wireless communication is based on radio technology.

[0107] In an embodiment, said wireless communication is bidirectional wireless communication.

[0108] In an embodiment, said consumption meters are arranged to receive configuration data, such as predetermined battery lifetime or reference power consumption, from said data collector through said wireless communication.

[0109] In an embodiment, said consumption meters are arranged to receive configuration data, such as predetermined battery lifetime or reference power consumption, from said backend system directly or via said data collector through said wireless communication.

[0110] In an embodiment, an individual reference power consumption is determined for each of said consumption meters on the basis of an estimated remaining battery capacity for the respective consumption meter and said predetermined battery lifetime common to said plurality of consumption meters.

[0111] In systems where the consumption meters do not have equal estimated remaining battery capacity, e.g. because of variations in capacity of new batteries, or because some meters have been operated more aggressively in the past, the reference power consumptions to target in each meter should be individual for each consumption meter based on the individual estimated remaining battery capacity.

[0112] In an embodiment, said reference power consumption is equal in consumption meters having equal estimated remaining battery capacity.

[0113] This may for example apply to new meters where the new batteries are manufactured with a high degree of similarity.

[0114] In an embodiment, said batteries of said consumption meters have equal battery capacity from manufacture.

[0115] In an embodiment, said reference power consumption is different in consumption meters having different estimated remaining battery capacity.

[0116] For example, consumption meters that have been operated more aggressively, or are having trouble with achieving the wireless communication, e.g. due to ever- changing wireless conditions in the environment, or is being used to relay data packages from meters located even further away.

[0117] In an embodiment, said reference power consumption is determined by each of said consumption meters.

[0118] In an embodiment, said reference power consumption is determined by said data collector and transmitted to said consumption meters.

[0119] In an embodiment, said reference power consumption is determined by a backend system of said meter reading system and transmitted to said consumption meters.

[0120] Data collectors or backend systems tasked with determining reference power consumption, may determine a common reference power consumption and transmit it to all consumption meters, or they may determine individual reference power consumptions for a number of consumption meters, and transmit them individually. [0121] In an embodiment, said predetermined battery lifetime common to said plurality of consumption meters is stored in the consumption meters during manufacture or installation.

[0122] Thereby for example a default datasheet lifetime value may be stored in the meters during manufacture, or the installer may input the predetermined battery lifetime into the consumption meters in connection with the installation process.

[0123] In an embodiment, said predetermined battery lifetime common to said plurality of consumption meters is negotiated among the consumption meters.

[0124] The consumption meters may agree on the common battery lifetime based on for example a suggestion from the consumption meters that are located in the best positions.

[0125] In an embodiment, said predetermined battery lifetime common to said plurality of consumption meters is controlled by said data collector.

[0126] The data collector, which communicates with all the consumption meters, or likewise a backend system, may be configured to determine the common predetermined battery lifetime.

[0127] In an embodiment, said predetermined battery lifetime common to said plurality of consumption meters is controlled by a backend system of said meter reading system.

[0128] In an embodiment, said predetermined battery lifetime common to said plurality of consumption meters is transmitted to said consumption meters from said data collector or said backend system.

[0129] In an embodiment, a first consumption meter of said plurality of consumption meters has transmission quality parameters that requires more power, such as higher transmission power and/or lower transmission rate, than a second consumption meter of said plurality of consumption meters and information quantity parameters that requires less power, such as longer transmission interval and/or lower data package payload size, than said second consumption meter.

[0130] According to the invention, the different consumption meters may certainly apply different settings of the parameters. As the different consumption meters, however, most often target the same average power consumption, the different settings will typically be balanced, so that meter with, e.g., higher transmission power necessarily applies less power consuming information quantity parameters, and vice versa for other consumption meters at more optimal locations not requiring high transmission power.

[0131] In an embodiment, the average power consumptions of the first and second consumption meters deviates less than 25%, such as less than 20%, such as less than 15%, such as less than 10%, from each other.

[0132] Despite possibly different parameter settings, the different consumption meters preferably target similar average power consumption.

[0133] In an embodiment, selected predetermined parameter combinations of specific transmission quality parameters and specific information quantity parameters are different in a first and a second consumption meter, respectively, of said plurality of consumption meters, wherein the average power consumptions of the first and second consumption meters deviates less than 25%, such as less than 20%, such as less than 15%, such as less than 10%, from each other.

[0134] In an embodiment, when said wireless communication has been achieved, at least one of said plurality of consumption meters has different settings of transmission quality parameters than a different at least one of said plurality of consumption meters.

[0135] In an embodiment, when said average power consumption is controlled according to said reference power consumption, at least one of said plurality of consumption meters has different settings of information quantity parameters than a different at least one of said plurality of consumption meters. [0136] In an aspect, the invention relates to a method of controlling average power consumption of a battery-powered consumption meter arranged to measure a value, such as accumulated volume, relating to a fluid flowing in a connected fluid pipe system and arranged to perform wireless communication of a data package relating to said value. The method comprises the steps of: controlling transmission quality parameters of said consumption meter to achieve said wireless communication; and controlling information quantity parameters of said consumption meter to control an average power consumption of said consumption meter in accordance with a reference power consumption of said consumption meter.

[0137] Everything described above in relation to consumption meters, meter reading systems, data collectors, backend systems, measured values, data packages, wireless communication, transmission quality parameters, information quantity parameters and the controlling of them, as well as average power consumption and reference power consumption, battery capacity and lifetime, etc., also applies to this aspect of the invention.

[0138] In an embodiment, said consumption meter is the consumption meter according to any of the above disclosure.

[0139] In an embodiment, said consumption meter forms part of a meter reading system according to any of the above disclosure, and wherein said wireless communication of said data package is to a data collector of said meter reading system.

[0140] In an embodiment, said step of controlling said transmission quality parameters comprises a step of increasing a transmission power and/or decreasing a data transmission rate until said wireless communication is achieved.

[0141] In an embodiment, said step of controlling said information quantity parameters to control said average power consumption, comprises a step of increasing said transmission interval and/or decreasing said data package payload size to counteract an increased power consumption caused by said controlling of said transmission quality parameters. [0142] In an embodiment, said steps of controlling said transmission quality parameters and controlling said information quantity parameters comprise selecting a predetermined parameter combination of specific transmission quality parameters and specific information quantity parameters based on a predetermined average power consumption associated with the predetermined parameter combination and said reference power consumption.

[0143] In an embodiment, said consumption meter comprises a plurality of predetermined parameter combinations of specific transmission quality parameters and specific information quantity parameters, and wherein predetermined average power consumptions associated with two or more of said plurality of predetermined parameter combinations deviates by less than 25%, such as less than 20%, such as less than 15% such as less than 10%.

[0144] Thereby the consumption meter has at least two different predetermined parameter combinations of parameters to choose from and still achieve substantially the same power consumption, at least within 25%. The different predetermined parameter combinations thus balanced with similar power consumption preferably offer a range of combinations from those that have transmission quality parameters requiring more power and thereby information quantity parameters requiring less power, to those that oppositely require less power for transmission for good conditions and thereby can spend more power on information quantity.

[0145] In an embodiment, predetermined power consumption classes or power consumption weights are assigned to specific transmission quality parameters and to specific information quantity parameters, and wherein said step of controlling said information quantity parameters comprises selecting one of said power consumption classes or power consumption weights for said information quantity parameters based on said reference power consumption to counteract one of said power consumption classes or power consumption weights for said transmission quality parameters selected at said step of controlling said transmission quality parameters. [0146] In an embodiment, said method comprises a step of receiving an operator input, such as manual setting or template setting, of transmission quality parameters and wherein said step of controlling said transmission quality parameters is based on said received operator input.

[0147] In an embodiment, said method comprises a step of automatically by an algorithm, e.g. a trial -and-error algorithm, setting said transmission quality parameters and wherein said step of controlling said transmission quality parameters is based on said automatically set transmission quality parameters.

[0148] The algorithm may for example increase transmission power or decrease data rate until wireless communication is achieved, or employ error correction when the error rate is unacceptable.

[0149] In an embodiment, said method comprises a step of updating said transmission quality parameters when said wireless communication fails, to achieve said wireless communication.

[0150] In an embodiment, said method comprises a step of updating said information quantity parameters upon change of said reference power consumption or said transmission quality parameters.

[0151] In an embodiment, said method comprises a step of counter-balancing said information quantity parameters upon change of said transmission quality parameters to maintain said average power consumption in accordance with said reference power consumption.

[0152] In an embodiment, said controlling said average power consumption in accordance with said reference power consumption comprises controlling said average power consumption to be within a predetermined goal tolerance of said reference power consumption.

[0153] In an embodiment, said predetermined goal tolerance is not more than ±40%, such as not more than ±25%, such as not more than ±15%, preferably not more than ±10%, most preferably not more than ±5% of said reference power consumption. [0154] In an embodiment, said method comprises a step of estimating a remaining battery lifetime of a battery of said battery-powered consumption meter by dividing an estimated remaining battery capacity of said battery by said average power consumption. [0155] In an embodiment, said method comprises a step of estimating a remaining battery lifetime of a battery of said battery-powered consumption meter on the basis of an estimated remaining battery capacity of said battery and current settings of said transmission quality parameters and said information quantity parameters.

[0156] In an embodiment, said method comprises a step of determining said reference power consumption on the basis of an estimated remaining battery capacity and a predetermined battery lifetime.

[0157] In an embodiment, said method comprises a step of measuring flow and/or volume of a fluid, such as water, such as cold water, hot water, central heating water, district heating water, etc., using said consumption meter, e.g. an ultrasonic water meter, being a fluid metering device.

[0158] In an embodiment, said method comprises a step of the consumption meter receiving configuration data, such as predetermined battery lifetime or reference power consumption, from a data collector or from a backend system directly or via a data collector through said wireless communication.

The drawings

[0159] Various embodiments of the invention will in the following be described with reference to the drawings where fig. 1 illustrates a prior art system, fig. 2 illustrates an embodiment of a meter reading system according to the invention, fig. 3 illustrates an embodiment of a consumption meter according to the invention, fig. 4 illustrates an embodiment of a meter reading system according to the invention, figs. 5 and 6 illustrate different scenarios of power consumption according to the invention, and fig. 7 illustrates an embodiment of a method of controlling average power consumption according to the invention.

Detailed description

[0160] To put the invention into perspective, Fig. 1 is provided as an illustration of a prior art system showing at least one of the problems related thereto. In the illustrated prior art system, four water consumption meters are transmitting data to a concentrator. The meters are distributed in a neighborhood at different distances to the concentrator. All the meters transmit several different kinds of data that are necessary and/or helpful for the system, administrator or users, for example meter reading, timestamp, status information, etc. As the meter in the lower right part of Fig. 1 is located very close to the concentrator, it only transmits at a low transmission power illustrated by the thin lines emerging from the antenna. This means, that its power consumption is low as illustrated by the “A” power consumption symbol. Consequently, its battery capacity is still close to full as illustrated by the full battery capacity symbol. The meter to the upper right is located a little farther away, so it communicates at a slightly higher transmission power, which makes its power consumption a little higher as illustrated by the “B” power consumption symbol, and thereby has already used more of the battery, as illustrated by the 75% battery capacity symbol. At approximately the same distance from the concentrator, is the lower left meter. However, as it has to transmit through a heavy concrete building, it has to apply the highest transmission power setting. This leads to the “D” power consumption symbol, and it has thus already used most of its battery capacity. To the upper left if the meter with the longest distance to the concentrator. It, too, has to use the highest transmission power setting, and leading the “C” power consumption system, and it has used about half of the battery already.

[0161] It is clear from Fig. 1, that this prior art system experiences very different battery lifetime of the water consumption meters. Some of the meters can go on for much longer, whereas others must soon be replaced. As described above in the background section, this may often be an undesired scenario for many administrators.

[0162] Fig. 2 illustrates an embodiment of a meter reading system according to the invention. It is drawn to facilitate comparison with the prior art system of Fig. 1. Fig. 2 is merely an example embodiment, and several other variations and possibilities are disclosed below with respect to the further drawings. Fig. 2 is further, for reasons of simplicity and illustration, deliberately exaggerated. A data collector DC, e.g. a concentrator, is provided strategically in a neighborhood. Consumption meters CM, e.g. water meters, are distributed in connection with fluid pipe systems, for example in each building or apartment in the neighborhood. Each consumption meter CM comprises a display D to locally indicate a meter reading or other information. The consumption meters CM also comprise an antenna A to establish wireless communication WLC of data packages DP with the data collector DC.

[0163] In order to achieve the wireless communication WLC, the different consumption meters CM because of their different locations and environments, may require different transmission settings. For example, the lower right consumption meter is closest to the data collector DC and therefore may communicate at the weakest transmission power setting as illustrated by the thin lines besides the antenna. The upper right consumption meter is a little farther from the data collector DC, and needs a higher transmission power as illustrated by stronger lines. The farthest consumption meter is the one at the upper left, and requires the highest transmission power as illustrated by bold lines around the antenna. The same goes for the lower left meter, which is only at medium distance from the neighborhood center, but needs to transmit through a heavier obstacle O than the other consumption meters.

[0164] The different transmission power settings of the four consumption meters CM in Fig. 2 are the same as in the prior art system of Fig. 1. However, by the solutions of the present invention, this embodiment achieves equal remaining battery lifetime as illustrated by the identical, 75% battery capacity symbols of batteries B of the consumption meters.

[0165] In order to achieve this coordinated remaining battery lifetime, the present embodiment has the different consumption meters CM transmit different amounts of data, thereby sending different data package DP sizes. For example, the lower right consumption meter using the least power for transmission, transmits a lot of need-to- know and nice-to-know information to the data collector DC. This requires a huge data package. The lower left consumption meter, which uses a lot of power to get data through the obstacle O, is set to only transmit the absolutely most necessary need-to- know data, such as for example the meter reading and related time of day. This makes for a very small data package. Similar adjustments to data package size are made to the remaining two consumption meters, leading to medium sized data packages.

[0166] As it requires longer time to transmit a large data package compared to a small data package, the transmission power of a consumption meter must be multiplied by the “on”-time of the radio to calculate the actual power consumption required for a transmission in order to be able to compare the meters. Thereby, the present invention has achieved for this embodiment that the combination of weak transmission power applied for relatively long time to transmit the largest data package, in fact is similar in terms of power consumption, to the combination of high transmission power applied for relatively short time to transmit the tiniest data package. The medium power multiplied by medium package size, also can be adjusted to give the same power consumption.

[0167] In other words, the average power consumption PA of all the consumption meters CM can be adjusted by careful selection of for example transmission power and data package size for each consumption meter independently. In the present embodiment, all the consumption meters CM are adjusted to consume equal average power as illustrated by the “B” power consumption symbols. In turn, the equal average power consumption also causes the battery capacities to remain equal over time, and thereby have the lifetime of the meters coordinated for the convenience of, for example, the administrator.

[0168] In the present embodiment, in order to coordinate the consumption meters CM to target the same average power consumption PA, the data collector DC decides on a common reference power consumption PREF which is transmitted to all the consumption meters CM. In this example, the data collector DC, or a backend system controlling the data collector, has decided that an appropriate power consumption level PREF to target throughout the meter reading system, would be level “B” as illustrated. Based on this, all consumption meters have managed to achieve the reference power consumption PREF for their individual average power consumption PA by means of the present invention. [0169] Meter reading systems may be based on unidirectional or bidirectional radio communication between meters and data collectors. Bidirectional communication allows the meter and collector to negotiate optimal transmission quality parameters, or at least enables the meter to know whether the data packages are being received, by exchange of acknowledgment messages. Further, bidirectional communication allows the collector or other unit, e.g. a backend system, in the meter reading system to upload updated configurations, firmware, etc., to the consumption meters. Such configurations may for example include settings of reference power consumption or even transmission quality parameters and information quantity parameters. With unidirectional configurations, meter data can be collected, but neither acknowledgments, nor configuration or control data, can be transmitted to the meters by that communication link straightaway. Unidirectional configurations may therefore implement a permanent or temporary alternative communication route for the transmission of the common reference power consumption PREF to the individual meters. For example, the common reference power consumption PREF can be brought to the meters by the installer who can set it upon installation and configuration of the meter, or the installer may utilize a temporary secondary communication route to test the transmission from the meter to the collector while on location for installation, and thereby set the common reference power consumption PREF and appropriate transmission quality parameters TQL to achieve the transmissions. Such a temporary secondary communication route may for example involve bidirectional near-field communication between the meter and the installer’s smartphone, and bidirectional telecom data communication between the smartphone and the backend. Thereby the transmission quality parameters TQL can be tested by the meter CM transmitting data packages DP to the data collector DC, and the data collector or connected backend system transmitting quality evaluations or configuration data to the communication meter CM via the installer’s smartphone.

[0170] As mentioned, Fig. 2 is merely one example of available adjustments according to the invention. Further possibilities within the invention are described below. [0171] Fig. 3 illustrates an embodiment of a consumption meter CM according to the invention. It is mounted on or in connection with a fluid pipe system FPS, carrying a fluid, for example cold water or hot water, and arranged to measure a value MV related to this fluid, for example flow rate, volume, temperature, etc. The consumption meter CM may for example be installed in a one-family house, an apartment building, an office building, an industrial building, an underground infrastructure system, etc., and it may for example be a water meter, a heat meter, a gas meter, a cooling meter, a waste water meter, or any other fluid measuring meter.

[0172] The consumption meter CM comprises a measuring unit MU arranged to perform the measurements and establish the measured value MV. The person skilled in the art of consumption meters knows several technologies for flow metering, etc., and may find examples of mechanical, ultrasonic or induction flow meters in text books and on the market in general, and it therefore poses no problem to provide a consumption meter CM with a measuring unit MU that is arranged to establish measured values MV such as flow rate or volume.

[0173] A processor P, a memory M, a battery B, a display D, an antenna A and a communication unit CU are also provided in the consumption meter CM, as also readily available to the skilled person.

[0174] The communication unit CU is configured to establish a wireless communication WLC using the antenna A, for example in order to transmit data packages DP to a data collector, backend system, etc.

[0175] Different from anything seen before, according to the invention, the consumption meter CM comprises a reference power consumption PREF, and some of its various settings and options related to communication and measurements are categorized into transmission quality parameters TQL and information quantity parameters IQN.

[0176] The transmission quality parameters TQL are the settings and options related to achieving the wireless communication WLC. This may for example in particular be the applied transmission power, as illustrated in Fig. 2, but other settings and options also belong to the transmission quality parameters TQL, such as data transmission rate, error correction type, modulation type and number of transmission repetitions. In various embodiments, various transmission quality parameters TQL, or combinations thereof, may provide the most optimal transmission quality, which basically means achieving the most reliable wireless communication at the lowest possible power consumption. In some scenarios with some kinds of challenges for the wireless communication, the best tools is increasing the transmission power, whereas in other scenarios with other kinds of obstacles or noise, more optimal adjustments may be to repeat all transmissions a number of times, transmitting at a lower data rate, change the modulation type, applying an error correction technique, etc. In an embodiment, such as systems based on LoraWan, NBIoT or WMBus, a single radio telegram can be retransmitted a number of times until a successful reception is confirmed by a receiver. Such transmission repetitions in close succession with a confirmation is often called retries, and the number of retries is then used as a Transmission quality Parameter.

[0177] The information quantity parameters IQN are the settings and options related to the amount of actual new information that is communicated by the data packages. For example when the transmission quality parameters are set to repeat data packages a certain number of times to increase the chance of at least one of them getting through, the additional data packages do not mean that more information is communicated, because it is just repetition of the same information. The amount of new information, on the other hand, in the settings of the information quantity parameters IQN refers for example to the amount of information in each data package, the intervals between new meter readings being transmitted, etc., such as transmission interval, data package payload size, data reduction method, data compression algorithm, etc.

[0178] In the example of Fig. 2, the solution applied to achieve equal average power consumption PA, was for example to reduce the data package DP payload size for each consumption meter CM depending on the available power after setting the transmission quality parameters TQL, as illustrated by the different sized data packages DP on the drawing. However, instead of adjusting the data package payload size, for example because it is not desirable if all the types of data are valuable, or the payload size is already reduced to the minimum, the solution could according to the invention have been to adjust other information quantity parameters, e.g. by letting the farther consumption meters CM transmit more rarely, e.g. only once for each 4 transmissions from the nearest consumption meter CM, or apply a compression technique to the data to be able to send the same amount of information by a smaller data package. The data compression may be a lossless compression, a lossy compression, or may for example remove information that the data collector DC or backend system BES will be able to derive automatically, so transmittal is not necessary. Example of the latter may for example include leaving out the date from a measurement timestamp if the system scheme is that measurements always belong to the same day they are transmitted, leaving out the major digits of the measurement value if consumption between measurement transmissions always is so low, that major digits never increase by more than one, leaving out part of an identification number, e.g. serial number, when for example all meters in the neighborhood shares the same first part of the number which thereby is redundant, etc.

[0179] The above-described information quantity parameters IQN primarily relates to the amount of information transmitted by the wireless communication WLC and are therefore herein denoted transmission information quantity parameters. Other information quantity parameters IQN may also be included in the power optimization, such as measuring interval, display sleep mode, etc. Such information quantity parameters IQN, which may be referred to as local information quantity parameters, may for example reduce the number of flow measurements or other measurements being made, thereby decreasing the measuring power consumption, or turn off the local meter display and thereby also allow display updates to be suspended, and requiring pressing a button to turn on the display for a short time. Combinations of different information quantity parameters IQN may preferably be adjusted for optimal efficiency, e.g. when the transmission interval is reduced, the measuring interval may also in some embodiments as well be reduced, if there is no further use of the additional measurements. [0180] The reference power consumption PREF may be stored in the consumption meter CM as part of a configuration, be determined by the consumption meter CM based on estimates of for example battery capacity, and/or be received as an instruction from for example a data collector DC or backend system BES. In any case, the reference power consumption PREF is the target power consumption for the consumption meter CM, which will lead to a certain estimated battery lifetime, and thereby also often consumption meter lifetime. As the instantaneous power consumed by the consumption meter CM of course varies with time, primarily depending on when measurements and transmission are made, the reference power consumption PREF serves as a target for the average power consumption PA by the consumption meter CM. Provided the consumption meter on average consumes the reference power, then the battery lifetime ideally will be the remaining battery capacity divided by the reference power consumption PREF. In order to target the reference power consumption PREF, the consumption meter CM comprises an average power consumption PA, which may for example be estimated or measured over time. Examples of the averaging of power consumption is disclosed on more detail with reference to Figs. 5 and 6.

[0181] As disclosed above, adjustments of transmission quality parameters TQL and information quantity parameters IQN also affects the average power consumption PA, and can thereby be used actively by the processor of the consumption meter CM to steer the average power consumption PA in a direction approaching the reference power consumption PREF. As the transmission quality parameters TQL and information quantity parameters IQN are often adjustable in discrete levels rather than continuously, and only to certain minimum or maximum values, and as some scenarios have more stable power consumption than others, the consumption meter CM may not be able to control the average power consumption PA to always stay exactly at the ordered reference power consumption PREF. The consumption meter CM may therefore comprise a goal tolerance GT defining the acceptable tolerance to which the average power consumption PA should equal the reference power consumption PREF. The goal tolerance GT may depend on the stability of the scenario, the available adjustable parameters vs the degree of fixed settings that the consumption meter is not allowed to adjust for power controlling purposes, etc. In turn, the goal tolerance GT thereby also affects how different the actual battery lifetime is allowed to become from the desired battery lifetime. In the most difficult embodiments with respect to for example instability and fixed settings, the goal tolerance may be as high as for example ±40%, meaning that the average power can be 40% lower or higher than the reference power, causing the same for the lifetime expectations. This may, however, still be better than prior art embodiments in such tough conditions. More preferably, the goal tolerance may be for example ±25%, ±15%, ±10% or ±5%. With ±5% tolerance and 10 years lifetime expectancy, all meters in a setup would reach a state of flat batteries within one year of each other (9.5-10.5 years), which is usually acceptable.

[0182] A less controllable factor to consider is the initial capacity of the batteries, and the self-discharge. The initial battery capacities are usually not perfectly equal, and the self-discharge depends on the local installation environments, in particular temperature. As the battery lifetime depends on both initial capacity, controlled power consumption and the self-discharge or uncontrolled power consumption, a certain degree of battery lifetime tolerance must be accepted. However, advanced embodiments of the present invention may provide some degree of control also over these aspects, by estimating the remaining battery capacity and self-discharge over time, and take this into account when estimating average power consumption PA and when adjusting parameters to target the reference power consumption PREF or when determining an individual or updated reference power consumption PREF to take into account an estimated difference in initial battery capacity or self-discharge from the expected values.

[0183] Fig. 4 illustrates an embodiment of a meter reading system MRS according to the invention. It comprises several consumption meters CM as described above, and a data collector DC. Other embodiments may have several data collectors DC, for example to better cover a large or difficult area. The consumption meters CM are distributed geospatially around the data collector DC, for example over an urban neighborhood, a suburban area, a countryside, etc., or vertically distributed in a high- rise building with one or more consumption meters on each floor, and a data collector DC on only some of the floors.

[0184] The data collectors DC may be fixed or mobile data collectors, e.g. concentrators, such as known by the person skilled in the art of radio-based meter reading. The data collectors DC are preferably communicatively coupled to a backend system BES, for example through public networks, such as the Internet by wired connection or WiFi, or telecom networks, landline or cell-based, or by proprietary communication technology. In some embodiments, the backend system BES is integrated together with the data collector DC for small-scale local meter reading systems MRS. The backend system BES may for example store the meter readings MV and other received information from the consumption meters CM and from other parties, e.g. utility providers, and perform the aggregation and other processing of the data to be able to produce consumption information, billing, etc.

[0185] The consumption meters CM are configured to perform wireless communication WLC at least of data packages DP comprising measured values MV to the data collector DC. In some embodiment, the wireless communication WLC is two-way communication and also provides for the data collector DC or other system, e.g. backend system BES to transmit control data or requests to the consumption meters CM. Such embodiments for example provide for updating the reference power consumption PREF of all or some consumption meters CM even long after the system has been deployed and configured, e.g. several years after.

[0186] As illustrated in Fig. 4, and readily reasonable to the skilled person, the different consumption meters CM may typically be located at different distances from the data collector DC and/or with different obstacles O for the wireless communication WLC, where for example metal objects and concrete objects may typically cause disturbance. Also, other external factors may affect the wireless communication WLC, e.g. disturbances from high voltage lines or wireless radio-based communication, e.g. WiFi and telecom, and other electromagnetic noise, etc. [0187] Despite the different challenges at different locations, the communication meters CM may achieve successful wireless communication WLC as disclosed above by adjusting the transmission quality parameters TQL. Because the kind and grade of wireless communication challenges differ between the individual consumption meters CM depending on their individual locations, the transmission quality parameter TQL settings will typically end up being different between the consumption meters, and thereby the power required for the wireless communication will differ between the consumption meters CM. According to the invention, to anyway achieve that the average power consumption PA of each consumption meter CM approaches the reference power consumption PREF, the consumption meters CM adjust the information quantity parameters IQN individually, for thereby making individual adjustments of their individual average power consumption PA. This is also further disclosed with reference to Fig. 7.

[0188] Figs. 5 and 6 illustrate different scenarios of power consumption according to embodiments of the invention. Fig. 5 illustrates a diagram of the instantaneous power P of a consumption meter CM over time t. The power pulses of highest level are the communication power level Pc, which occurs every time the consumption meter CM establishes wireless communication WLC to transmit a data package DP as described above. In the illustrated diagram, this occurs 5 times in Fig. 5. A smaller power pulse of a measurement power level Pm is experienced each time the consumption meter CM performs a measurement, for example an ultrasonic flow measurement. This occurs quite often in the scenario of Fig. 5, with a total of 18 times. One of the times, the measurement and wireless communication coincides in time, making the highest power level as both the measurement power Pm and the communication power Pc are drawn at the same time. When neither measurement, nor communication, takes place, the consumption meter CM in this simplified illustration draws a constant base power level Pb. The person skilled in the art of power behavior of digital circuits understands the simplified illustration of Figs. 5-6, appreciating that real-life power behavior is more complicated but nonetheless explainable by the principles of these diagrams. The same applies to the relative levels between the communication power Pc, the measuring power Pm and the base power Pb, and the relative timing between communication pulses, measuring pulses and idle time, as both levels and timing in various real systems may be quite different but can be explained in principle by the drawing. In an embodiment an even lower sleep mode power level may be applied.

[0189] With the simplified example of Fig. 5, the average power consumption PA is indicated by the dashed line. The average power consumption PA of consumption meter CM may be determined on the basis of the power consumption during the entire life so far of the consumption meter, or it may be determined on the basis of a reasonable time window. In the latter case, the time window on which the averaging is based should preferably cover several instances of all the different power levels and patterns in order to provide a sufficiently stable average. However, estimating a lifetime average power consumption may not be suitable for all embodiments, as changes in the average power consumption PA need to be discovered, at least when adjustments are made to the parameters, and/or the reference power consumption PREF is changed.

[0190] Fig. 6 illustrates the situation of another consumption meter CM located at a longer distance from the data collector DC. According to the invention, the transmission quality parameters TQL have been adjusted to achieve the wireless communication WLC, which in this case means that the communication power level Pc has been increased, as seen by the higher pulses compared to Fig. 5. In order to maintain the same average power consumption PA as the consumption meter of Fig. 5, the consumption meter CM is adjusting its information quantity parameters IQN to transmit only at a double transmission interval compared to Fig. 5, meaning that the consumption meter CM of Fig. 6 only transmits a data package every second time the meter of Fig. 5 is transmitting. The measurement power Pm and base power/ ¹ / are not adjusted. The backend system BES thereby receives measurement values MV from the Fig. 5-meter at a double time-resolution compared to the Fig. 6-meter. This means that the fluid value and derived information such as for example water consumption or water billing can only be calculated and visualized more roughly and with a larger latency for the Fig. 6-meter. Despite this drawback, the configuration according to the invention is assumed to be considered an advantage for many meter reading systems, over the usual case of having the remotely or non-ideally located meters run flat over a range of different unexpected times much sooner than the more ideally located meters.

[0191] Fig. 7 illustrates an embodiment of a method of controlling average power consumption according to the invention. The consumption meter CM first determines the reference power consumption PREF in accordance to which the controlling should be performed. The determination of reference power consumption PREF may as described above for example involve receiving a reference power consumption PREF or having it configured at installation time or estimating it locally by the consumption meter CM. The latter may for example comprise the consumption meter estimating a remaining battery capacity and calculating a reference power consumption PREF on the basis of remaining battery capacity and a predetermined, desired battery lifetime.

[0192] Next step is to adjust transmission quality parameters TQL until wireless communication WLC of data packages DP is achieved. This may as described above involve adjusting parameters such as transmission power, data rate, modulation type, etc. This step may be performed iteratively, by trying out certain settings and combinations of settings, check if acceptable wireless communication is achieved, try again with other settings, etc., until successful. The step may also include receiving specific instructions from a data collector or operator about specific values of transmission quality parameters TQL to apply.

[0193] After the wireless communication WLC is achieved, the average power consumption PA is now adjusted in accordance with the determined reference power consumption PREF. The average power consumption PA is preferably adjusted by adjusting information quantity parameters IQN, affecting the amount of data being sent from the consumption meter CM, and thereby also affecting the average power consumption PA. This step may be performed iteratively as described above for the TQL adjustment step, or be performed by looking up or calculating counter-balancing values of information quantity parameters IQN corresponding to the adjusted transmission quality parameters TQL. Prioritization or minimum and maximum values for the information quantity parameters IQN may also be received from an external party such as the data collector DC, backend system BES or an operator, for example to set which data should at least be transmitted at a minimum, the maximum transmission interval, whether data compression is supported, etc. When adjustments make the average power consumption PA to be similar to the reference power consumption PREF within a predetermined goal tolerance GT, the method can go on to next step, or attempt further optimization of the information quantity parameters IQN.

[0194] With the above result of average power consumption PA approaching reference power consumption PREF and wireless communication working, the power controlling method becomes idle until changes appear or become necessary.

[0195] One kind of change that requires a little more work from the algorithm is when the reference power consumption PREF is changed. This may for example be by instruction from outside the consumption meter, e.g. received from data collector DC, backend system BES or an operator by configuration data, or come from the consumption meter CM itself. The change of reference power consumption PREF may for example be caused by an operator extending the desired lifetime by a couple of years, or because it is realized that the batteries have less capacity or higher self discharge than originally expected. When the reference power consumption PREF is changed, the power controlling method method goes back to the step of adjusting the information quantity parameters IQN to make the average power consumption PA approach the new reference power consumption PREF. It is not necessary to go back to the step of adjusting transmission quality parameters TQL, as no changes to the wireless communication WLC situation is expected.

[0196] Another kind of change which will engage the method again, is when the wireless communication WLC experiences trouble. This may e.g. be caused by changes in the environment of the consumption meter CM, in the line of sight to the data collector DC or by changes to the data collector DC or its environment. When the wireless communication WLC gets into trouble, the method goes back to the step of adjusting transmission quality parameters TQL, in order to solve the communication problems. When this is done, the information quantity parameters IQN are again adjusted until the average power consumption PA approaches the reference power consumption PREF and the method goes back to idling.

[0197] The method is preferably carried out automatically by the processor P of the consumption meter CM, but may also be carried out semi-automatically or manually by an operator overlooking the result of each step before continuing or even performing each step.

[0198] List of reference signs:

A antenna

B battery

BES backend system

CM consumption meter

CU communication unit

D display

DC data collector

DP data package

FPS fluid pipe system

GT goal tolerance

IQN information quantity parameter

M memory

MRS meter reading system

MU measuring unit

MV measured value such as accumulated volume

O obstacle

P processor

PA average power consumption

Pb base power level

Pc communication power level

Pm measuring power level

PREF reference power consumption

TQL transmission quality parameter

WLC wireless communication