Method and apparatus for triggering an uplink transmission at an ambient IoT device based on a level of stored electrical energy

Abstract

The present disclosure relates to methods and apparatus for enabling a user equipment (UE) (20) including a wireless device (25) having an energy harvesting unit (254) that stores electrical energy in an energy storage unit (255) of the wireless device to determine whether to initiate an uplink data transmission based on an amount of electrical energy stored in the energy storage unit (255).

Description

Technical FieldThe present disclosure relates to wireless communication systems, and more particularly relates to methods and apparatus for enabling a very low power consumption wireless device to determine whether to initiate an uplink data transmission based on at least one amount of electrical energy stored in an energy storage unit of the wireless device.BackgroundThe Internet of Things (IoT) allows various devices to connect to the Internet to send data, receive instructions, or both. Dozen billions of IoT devices are already deployed and the global number of IoT devices is expected to increase rapidly. Thus, massive connectivity is needed. However, supplying these billions of IoT devices with power presents a critical challenge and the deployment of power cables or periodic replacement / recharging of batteries is not a practicable solution.3GPP (third generation partnership project) is currently investigating new loT technologies to discover within the 3GPP systems new markets whose number of connections and / or device density may be orders of magnitude higher than existing 3GPP IoT technologies and which may provide complexity and power consumption orders of magnitude lower than existing 3GPP technologies such as narrowband IoT (NB-IoT / oT) and long-term evolution-machine-type (LTE-MTC) communication. Specifically, 3GPP currently defines A-loT (ambient / oT) technologies (see, e.g., technical report TR 38.848 V18.0.0) that aim to enable loT devices with very low power consumption that could be either batteryless devices with no power storage capability (that perform backscatter transmission) or devices with a power storage that does not need to be manually replaced or recharged (that performs wireless energy harvesting (EH) from one or more power sources).With "very low power consumption" or "A-loT" devices, the authors mean devices having a peak power consumption of less than 1 mW or even less than 100 μW or less than 10 μW. For example, Ambient IoT currently aims to enable A-IoT devices having the following characteristics:about 1 μW peak power consumption with energy storage, with neither DL (downlink) nor UL (uplink) amplification in the device (the UL transmission of the device is backscattered on an externally provided carrier wave),below a few hundred μW peak power consumption with energy storage, with DL and / or UL amplification in the device (the UL transmission of the device may be generated internally by the device or backscattered on an externally provided carrier wave).Typically, such A-IoT devices have only a limited energy storage and the usage of the stored electrical energy must be optimized to reduce the likelihood that uplink data transmission fails. This is because failed data transmissions result in a waste of uplink resources and an increased consumption of electric power and must be avoided.SummaryThe present disclosure aims to improve the situation. In particular, the present disclosure aims to address at least some of the limitations of the prior art discussed above. In particular, the present disclosure aims to propose a solution that makes it possible to reduce the probability of failed uplink data transmissions from wireless devices, such as A-IoT devices.To this end, it is proposed to evaluate a measure of electrical energy stored in a wireless device and use the measure of electrical energy stored to determine whether the wireless device can proceed with uplink data transmission or whether the uplink data transmission should instead be delayed.According to a first aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, the method being implemented by a wireless device of the wireless communication system, the wireless device comprising an energy harvesting unit configured to convert ambient energy into electrical energy stored in an energy storage unit of the wireless device, the wireless device further comprising a communication unit configured to exchange data with a radio access network (RAN) of the wireless communication system, the method comprising: in response to determining that uplink data is to be transmitted to the RAN:measuring a measure of the electrical energy stored in the energy storage unit,evaluating a triggering criterion for an uplink transmission by comparing the measure of the stored electrical energy with a predetermined threshold value of the energy measure,in response to the uplink transmission triggering criterion being verified: transmitting uplink data to the RAN,in response to the uplink transmission triggering criterion not being verified: delaying transmission of the uplink data to the RAN.In some embodiments, the method according to the first aspect may further comprise one or more of the following optional features, which are considered either alone or in a technically possible combination.In some embodiments of the method according to the first aspect, the threshold value of the energy measure is determined based on information received from the RAN regarding at least one threshold value of the energy measure.In some embodiments of the method according to the first aspect, the information regarding at least one threshold value of the energy measure is received in system information broadcast by the RAN and / or in a signaling message specifically addressed to the wireless device or to a group of wireless devices including the wireless device.In some embodiments of the method according to the first aspect, the transmission of the uplink data to the RAN is delayed until the triggering criterion for an uplink transmission is verified.In some embodiments of the method according to the first aspect, the triggering criterion for an uplink transmission is verified if the amount of stored electrical energy is greater than the predetermined threshold value of the amount of energy.In some embodiments of the method according to the first aspect, the triggering criterion for an uplink transmission is verified regardless of the measure of the stored electrical energy:when the delay introduced for performing the transmission of the uplink data reaches a predetermined maximum delay, orwhen the number of uplink discarded transmission opportunities reaches a predetermined maximum number of uplink discarded transmission opportunities.In some embodiments of the method according to the first aspect, the wireless device determines that uplink data is to be transmitted by receiving a trigger signal for uplink transmission from the RAN.In some embodiments of the method according to the first aspect, the energy harvesting unit is a radio unit configured to convert a received radio frequency signal into electrical energy.According to a second aspect, the present disclosure relates to a wireless device comprising at least one memory and at least one processor configured to perform a method according to any of the embodiments of the first aspect.According to a third aspect, the present disclosure relates to a user equipment (UE) including a wireless device according to any one of the embodiments of the present disclosure.According to a fourth aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, the method being implemented by a base station (BS) of a radio access network (RAN) of the wireless communication system, the BS being configured to exchange data with a wireless device comprising an energy harvesting unit configured to convert ambient energy into electrical energy stored in an energy storage unit of the wireless device, the method comprising transmitting, to the wireless device, information relating to at least one threshold value of the energy measure.In some embodiments, the method according to the fourth aspect may further comprise one or more of the following optional features, which are considered either alone or in a technically possible combination.In some embodiments, the method according to the fourth aspect comprises estimating a channel quality value of a propagation channel between the BS and the wireless device and determining the at least one threshold value of the energy measure based on the estimated channel quality value.In some embodiments, the method according to the fourth aspect includes transmitting a trigger signal for an uplink transmission to the wireless device as an indication that uplink data is to be transmitted by the wireless device to the RAN.In some embodiments, the method according to the fourth aspect includes starting transmitting an energy harvesting signal to the wireless device before transmitting the trigger signal for an uplink transmission to this wireless device.In some embodiments of the method according to the fourth aspect, the information regarding at least one threshold value of the energy measure is broadcast in system information and / or transmitted in a signaling message specifically addressed to the wireless device or to a group of wireless devices containing the wireless device.According to a fifth aspect, the present disclosure relates to a base station (BS) comprising at least one memory and at least one processor configured to perform a method according to any of the embodiments of the fourth aspect.According to a sixth aspect, the present disclosure relates to a wireless communication system including at least one base station according to any one of the embodiments of the present disclosure and at least one user equipment according to any one of the embodiments of the present disclosure.According to a seventh aspect, the present disclosure relates to a computer program product comprising instructions which, when executed by at least one processor, configure the at least one processor to perform a method for exchanging data according to one of the embodiments of the present disclosure. The computer program product may use any programming language and may be in the form of source code, object code, or any form between source code and object code, such as in a partially compiled form, or in any other desired form.According to an eighth aspect, the present disclosure relates to a (non-transitory) computer readable storage medium comprising instructions which, when executed by at least one processor, configure the at least one processor to perform a method for transmitting control messages according to one of the embodiments of the present disclosure.Brief Description of the DrawingsThe invention will be better understood from reading the following description, given as an example which is by no means restrictive, and in which reference is made to the figures which show:FIG. 1 : schematic representations of various possible topologies of a wireless communication system,FIG. 2 is a schematic illustration of an example of a wireless device,FIG. 3 is a schematic illustration of an example of a BS,FIGS. 4 and 5 are flowcharts illustrating examples of methods for exchanging data implemented by a wireless device of a UE and a BS, respectively,FIGS. 6 and 7 are flowcharts illustrating other examples of methods for exchanging data implemented by a wireless device of a UE and a BS, respectively,FIGS. 8 and 9 are flowcharts illustrating other examples of methods for exchanging data implemented by a wireless device of a UE and a BS, respectively.In these figures, reference numerals identical from one figure to another denote identical or analogous elements. For clarity, the elements shown are not to scale unless expressly stated otherwise.DETAILED DESCRIPTIONThe following detailed description with reference to the figures is intended to be a description of various configurations and not to represent the only configurations in which the concepts described herein may be practiced. The detailed description contains specific details for the purpose of comprehensively understanding the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. For example, although 3GPP terminology, e.g., from 5G NR, may be used in this disclosure to explain embodiments herein, this should not be considered limiting of the scope of the present disclosure.In general, all terms used herein should be interpreted according to their usual meaning in the respective technical field, unless another meaning is clearly indicated and / or arises from the context in which it is used. All references to a / the / the / the element, device, component, means, step, etc. are open to be construed as referring to at least one occurrence of the element, device, component, means, step, etc., unless expressly stated otherwise. Also, the order of steps of any methods disclosed herein, particularly in the figures, is provided for illustrative purposes only and is not intended to limit the present disclosure, which may be applied with the same steps performed in a different order and / or with all or a portion of the steps performed in parallel or together unless a step is expressly described as following or preceding another step and / or where it is implicit that a step must follow or preceding another step. Furthermore, steps shown in a figure, which are surrounded by a dashed line, are to be considered as optional for the embodiment shown in this figure. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment as appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objects, features, and advantages of the included embodiments will become apparent from the following description.FIG. 1 schematically illustrates an example of a wireless communication system, which may be, for example, a 5G NR wireless communication system. In particular, FIG. 1 illustrates a RAN of the wireless communication system used to exchange data with UEs 20 via radio signals. The RAN may, for example, send data (DL) to the UEs 20, for example data received from a core network (CN, not shown in the figures). The RAN may also receive data from the UEs 20 (uplink UL) and this data may be forwarded to the CN.In the example illustrated by FIG. 1, the RAN includes a base station (BS) 30. of course, the RAN may include more than one BS 30 to increase the coverage area of the wireless communication system. Each of these BSs may be referred to as NB, eNodeB (or eNB), gNodeB (or gNB in the case of a 5G NR wireless communication system), an access point, or the like, depending on the wireless communication standard or standards implemented.In the example illustrated by FIG. 1, only one UE 20 is shown including a wireless device 25 that provides the UE 20 with wireless connectivity to the RAN of the wireless communication system. Part a) of FIG. 1 schematically illustrates an example in which the UE 20 directly exchanges data (payload data and control data) with a BS 30 of the RAN (referred to as Topology 1 in TR 38.848 V18.0.0). Part b) of FIG. 1 schematically illustrates an example in which the UE 20 indirectly exchanges data (payload data and control data) with a BS 30 of the RAN via one or more intermediate nodes 31 (referred to as Topology 2 in TR 38.848 V18.0.0). Each intermediate node 31 may be, for example, a relay, an IAB (Integrated Access and Backhaul) node, another UE 20, a repeater, a reconfigurable intelligent surface (RIS), etc.FIG. 2 schematically illustrates an example of a wireless device 25 suitable for implementing any method discussed in the present disclosure as performed at a UE 20. Basically, the wireless device 25 corresponds to a device that provides wireless connectivity with the RAN of the wireless communication system and that can be used to exchange data with the RAN. The wireless device 25 is, for example, an A-IoT device, i.e., a wireless device having a peak current consumption of less than 1 mW or even less than 100 μW or even less than 10 μW.Such a wireless device 25 may be included in a UE 20 as illustrated by FIG. 2. The UE 20 may be, for example, a mobile phone, a wireless modem, a wireless communication device, a handheld device, a laptop computer, or the like. In preferred examples, the UE 20 may also be an Internet of Things (IoT) device, such as a wireless camera, smart sensor, smart meter, smart glasses, vehicle (manned or unmanned), global positioning system device, etc., or any other device capable of executing applications where data needs to be exchanged with remote receivers via the wireless device 25.As illustrated by FIG. 2, the wireless device 25 includes one or more processors 250 and one or more memories 251. The one or more processors 250 may include, for example, a central processing unit (CPU), a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc. The one or more memories 251 may include any type of computer readable volatile and nonvolatile memory (magnetic hard disk, solid state memory, optical disk, electronic memory, etc.). The one or more memories 251 may store a computer program product 252 in the form of a set of program-encoded instructions to be executed by the one or more processors 250 to implement all or part of the steps of a method for exchanging data performed on the side of a UE according to any of the embodiments disclosed herein.As illustrated by FIG. 2, the wireless device 25 also includes a (wireless) communication unit 253 configured to (directly or indirectly) exchange data with BSs 30 of the RAN using radio signals. The communication unit 253 may implement one or more wireless communication protocols and may be, for example, a 3G, 4G, 5G, NR, WiFi, WiMax, etc. transceiver or the like. In preferred embodiments, the (wireless) communication unit 253 comprises a 5G NR wireless communication unit.As discussed above, in some examples, communication unit 253 may not include either a DL (downlink) or an UL (uplink) enhancement capability (the UL transmission is backscattered on an externally provided carrier wave). In other examples, the communication unit 253 may include a DL and / or UL gain (the UL transmission may be internally generated by the wireless device or backscattered on an externally provided carrier wave).As illustrated by FIG. 2, the wireless device 25 also includes an energy harvesting unit 254 and a wireless device energy storage unit 255.The energy storage unit 255 may be any type of electric energy accumulator and may include, for example, one or more capacitors, one or more batteries, etc. The energy storage unit 255 is used to provide electrical energy to the other devices of the wireless device 25 that require electrical energy, such as the one or more processors 250, the one or more memories 251, and in some cases the (wireless) communication unit 253.The energy harvesting unit 254 is configured to convert ambient energy into electrical energy that is stored in the energy storage unit 255. By "ambient energy", the authors mean energy from energy sources located outside the wireless device 25 received at the wireless device 25 without any wires between the energy sources and the wireless device 25. Thus, the energy harvesting unit 254 is configured such that the wireless device 25 can operate in an autonomous manner without the energy storage unit 255 having to be manually replaced or recharged. The energy harvesting unit 254 may, for example, collect energy from various energy sources, including sun, heat, motion or oscillations, radio frequency (RF), etc.In preferred embodiments, the energy harvesting unit 254 includes at least one radio unit configured to convert RF signals into electrical energy that is stored in the energy storage unit 255. These RF signals may be, for example, external RF signals, i.e., RF signals that do not originate from the interior of the wireless communication system itself, but from RF sources located outside the wireless communication system. For example, external RF signals may originate from external 3G, 4G, 5G, NR, WiFi, WiMax, Bluetooth, DAB, etc. devices located proximate to the wireless device 25. Alternatively, or in combination, the RF signals may originate from within the wireless communication system, for example, BSs 30 of the RAN, which may transmit an energy harvesting (RF) signal to wireless (A-loT) devices 25 in their coverage area, and / or devices separate from the BSs 30, but used to enable energy harvesting at the wireless (A-loT) devices 25 of the wireless communication system. In some examples, when RF signals are used to supply electrical energy to the energy storage unit 255, the energy harvesting unit 254 may be included in the (wireless) communication unit 253.FIG. 3 schematically illustrates an example of a BS 30 suitable for implementing a method discussed in the present disclosure as performed by the RAN.As illustrated by FIG. 3, the OS 30 includes one or more processors 300 and one or more memories 301. The one or more processors 300 may include, for example, a central processing unit (CPU), a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc. The one or more memories 301 may include any type of computer readable volatile and nonvolatile memory (magnetic hard disk, solid state memory, optical disk, electronic memory, etc.). The one or more memories 301 may store a computer program product 302 in the form of a set of program-encoded instructions to be executed by the one or more processors 300 to implement all or part of the steps of a method for exchanging data performed on the side of the RAN according to any of the embodiments disclosed herein.As illustrated by FIG. 3, the BS 30 also includes a wireless communication unit 303 configured to exchange data with UEs 20 using radio signals, and more specifically, with (wireless) communication units 253 of wireless devices 25 included in these UEs 20. The wireless communication unit 303 may be, for example, a 3G, 4G, 5G, NR, WiFi, WiMax, etc. transceiver or the like. In preferred embodiments, the wireless communication unit 303 of the BS 30 comprises a 5G NR transceiver. In some examples, the wireless communication unit 303 may also transmit carrier waves to the wireless devices 25 that perform uplink transmissions with backscatter.As illustrated by FIG. 3, in some examples, the BS 30 may also include a network communication unit 304 configured to exchange data with other base stations of the RAN and / or with the CN. The network communication unit 305 may support one or more suitable communication protocols, which may be wired (including fiber optic) and / or wireless.As illustrated by FIG. 3, in some examples, the BS 30 may also include an energy harvesting signal generator 305 that generates energy harvesting (RF) signals that enable wireless devices 25 in its coverage area to feed electrical energy to their energy storage units 255 via their energy harvesting units 254. The energy harvesting (RF) signals may take any suitable form that enables the energy harvesting units 254 to store electrical energy in the energy storage units 255 of the wireless devices 25. The selection of a specific energy harvesting (RF) data rate is in a specific and non-limiting embodiment of the present disclosure. As mentioned above, such energy harvesting (RF) signals may optionally be generated alternatively or in combination therewith by other devices that are separate from the BSs 30 of the RAN.As discussed above, the above disclosure aims to enable a wireless device 25 to decide whether uplink data transmission can be initiated by directly or indirectly considering a measure of electrical energy stored in its energy storage unit 255. Considering the amount of stored electrical energy may be used to avoid initiating uplink data transmission, for example, when the stored electrical energy is low, which could result in a failed uplink data transmission. Thus, considering the amount of stored electrical energy may reduce the likelihood of failed uplink transmissions for A-IoT devices.The authors now present examples of signaling and arbitration strategies that may be implemented to achieve a higher probability of successful uplink data transmissions by the wireless device 25 and thereby reduce uplink resource waste and power consumption.Measure of Stored Electrical EnergyFIG. 4 illustrates a diagram showing steps of an exemplary embodiment of a method 40 for exchanging data implemented by a wireless device 25 of a UE 20. FIG. 5 illustrates a diagram showing corresponding steps of an example embodiment of a method 50 for exchanging data implemented by a BS 30 of the RAN.As illustrated by FIG. 4, the data exchanging method 40 includes a step S 40 of determining that uplink data is to be transmitted by the wireless device 25.In some examples, step S 40 may consist in detecting that uplink data is available at the UE 20 and is to be transmitted to the RAN by the wireless device 25.Alternatively, or in combination, the wireless device 25 may determine that uplink data is to be transmitted to the RAN when it detects an impending UL transmission opportunity. For example, a UL transmission opportunity corresponds to UL resources that the wireless device 25 can use. For example, such UL resources may be, for example, contention-based UL resources, such as random-access channel (RACH) UL resources or configured grant (CG) UL resources, etc. In other examples, such UL resources may be specifically allocated to wireless device 25, such as scheduling request (SR) resources.Alternatively or in combination, uplink data transmission may be triggered by the RAN. In such examples, step S 40 may include receiving a trigger signal for an uplink transmission from the RAN. Thus, when the wireless device 25 receives such an uplink transmission trigger signal from the RAN, the wireless device 25 may evaluate whether the uplink data transmission may be initiated, for example, at an imminent UL transmission opportunity. Of course, such uplink data transmission should be initiated only when uplink data is available at the UE 20 or may be collected by the UE in response to receiving the trigger signal for uplink transmission from the RAN. In the present disclosure, the authors assume in a non-limiting manner that uplink data is available or may be collected by the UE 20, and focus on other conditions that the wireless device 25 may take into account to decide whether the uplink data transmission should be initiated.To reduce its consumption of electric power, the wireless device 25 may be placed in a sleep mode. In such a case, the wireless device 25 must enter an active mode to be able to perform the uplink data transmission. Such a transition may be triggered by the RAN by sending a wake-up signal to the wireless device 25. In such a case, the trigger signal for an uplink transmission may correspond to the wake-up signal that the wireless device 25 switches from a sleep mode to an active mode, or may be transmitted by the RAN after transmitting a wake-up signal to the wireless device 25.As illustrated by FIG. 4, the method 40 of exchanging data in response to determining, at step S 40, that uplink data is to be transmitted includes a step S 41 of measuring a measure of the electrical energy stored in the energy storage unit 255. The amount of stored electrical energy may be measured using any method known to those skilled in the art, and the selection of a specific method is in accordance with a specific, but non-limiting embodiment of the present disclosure. Also, the measured amount of electrical energy may take any suitable format that allows it to be compared to a threshold, for example. For example, the amount of stored electrical energy may correspond to an energy value expressed, e.g., in joules or watt hours, or a percentage indicative of the charge of energy storage unit 255 (e.g., 0% indicative that energy storage unit 255 is empty and 100% indicative that energy storage unit 255 is fully charged), etc.As illustrated by FIG. 4, the method 40 for exchanging data comprises a step S 42 of evaluating a triggering criterion for an uplink transmission by comparing the measure of the stored electrical energy with a predefined threshold value of the energy measure. When the triggering criterion for an uplink transmission is verified (reference sign S 42 ain FIG. 4 ), the data exchanging method 40 includes a step S 43 of transmitting uplink data (i.e., all or a part of the uplink data available at the wireless device 25) to the RAN. On the other hand, if the uplink transmission triggering criterion is not verified (reference sign S 42 bin FIG. 4 ), the data exchanging method 40 includes a step S 44 of delaying transmission of the uplink data to the RAN.Thus, the wireless device 25 takes into account the amount of stored electrical energy stored in the energy storage unit 255 before initiating uplink data transmission to assess whether the amount of stored electrical energy is sufficient for uplink data transmission to be likely to succeed. For example, the triggering criterion for an uplink transmission is verified if the amount of stored electrical energy is greater than the predefined threshold value of the amount of energy. If the amount of stored electrical energy is considered insufficient, the uplink data transmission is delayed, e.g., upon a subsequent uplink transmission opportunity, to enable the wireless device 25 to continue to feed electrical energy into the energy storage unit 255.It should be noted that in some examples, it is also possible to consider other parameters for determining whether the wireless device 25 can initiate the uplink data transmission. For example, the evaluation of the triggering criterion for an uplink transmission may also take into account the volume of uplink data to be transmitted, the channel quality of the propagation channel between the RAN and the wireless device 25, etc. More generally, the uplink transmission triggering criterion may take into account any parameter relevant to assessing whether uplink data transmission is likely to be successful, wherein the amount of electrical energy stored is an important parameter in the context of A-IoT devices. Thus, in some examples, the triggering criterion for an uplink transmission may be considered verified if the amount of stored electrical energy is greater than the predetermined threshold amount of energy and if one or more other conditions are verified, for example if the channel quality value is greater than a predetermined threshold amount of channel quality value, etc.For example, the threshold amount of energy at the wireless device 25 may be predefined (e.g., indicated by a standard or by a calibration of the wireless device 25).In other examples, and as illustrated by FIG. 4, the method 40 of exchanging data may include a prior step S 45 of receiving, from the RAN, information regarding at least one threshold amount of energy, and the threshold amount of energy may be determined by the wireless device 25 based on the received information. For example, the received information may include the values for one or more thresholds of the amount of energy that may be used by the wireless device 25. For example, the received information may consist of a single threshold amount of energy that the wireless device 25 may directly use in evaluating the triggering criterion for an uplink transmission. In other examples, the received information may include a plurality of different thresholds of the energy measure, which may be associated with respective traffic classes (e.g., priority of uplink data to be transmitted, etc.), respective channel quality values, respective volumes of uplink data to be transmitted, etc., for example. In such a case, the wireless device 25 may select an energy measure threshold from the plurality of received energy measure thresholds based on the transmission context of the uplink data (traffic class, channel quality value, volume of uplink data, etc.).For example, the information regarding at least one threshold amount of energy may be received in system information broadcast by the RAN and / or in a signaling message specifically addressed to the wireless device 25 or to a group of wireless devices 25 containing the wireless device. In the latter case, the trigger signal for uplink transmission may optionally include an identifier of the wireless device 25 or the group of wireless devices to enable the wireless device 25 to detect that it is the receiver of this information.As mentioned above, if the trigger criterion for an uplink transmission is not verified, the uplink data transmission is delayed (step S44). For example, the uplink data transmission may be delayed by a predetermined delay that begins when it is determined that the uplink data transmission is to be delayed. In such a case, the uplink data transmission can be initiated as soon as the predetermined delay has expired without the triggering criterion for an uplink transmission having to be evaluated again.In other examples and as illustrated by FIG. 4, the evaluation of the triggering criterion for an uplink transmission may be repeatedly performed, for example at each subsequent uplink transmission opportunity, until the triggering criterion for an uplink transmission is verified. For example, the uplink data transmission may be initiated as soon as the amount of stored electrical energy is greater than the predetermined threshold value of the amount of energy.In some examples, the triggering criterion for an uplink transmission may be verified at some time, regardless of the amount of electrical energy stored, to ensure that the uplink data transmission is not delayed infinitely. For example, the triggering criterion for an uplink transmission may be verified when the delay introduced for performing the transmission of the uplink data reaches a predetermined maximum delay. According to another example, the triggering criterion for an uplink transmission may be verified when the number of uplink burst opportunities reaches a predetermined maximum number of uplink burst opportunities. Thus, such constraints ensure that the uplink data transmission is not delayed by more than a predetermined maximum delay or by more than a predetermined maximum number of rejected uplink transmission opportunities.In alternative examples, the uplink data to be transmitted may be discarded if the triggering criterion for an uplink transmission is still not verified after a predetermined maximum delay or after a predetermined maximum number of discarded uplink transmission opportunities.As discussed above, FIG. 5 illustrates a diagram illustrating corresponding steps of an example embodiment of a method 50 for exchanging data that may be implemented by a BS 30 when the wireless device 25 implements the method 40 for exchanging data illustrated by FIG. 4.As illustrated by FIG. 5, the method 50 of exchanging data includes a step S 50 of transmitting, to the wireless device 25, information regarding at least one threshold value of the amount of energy (received by the wireless device 25 at step S 45) to be used by the wireless device 25 to evaluate the triggering criterion for an uplink transmission. As discussed above, this information may be broadcast in system information and / or transmitted in a signaling message specifically addressed to the wireless device 25 or to a group of wireless devices that includes the wireless device 25.In some examples, the method 50 of exchanging data may include a step (not shown in the figures) of estimating a channel quality value of the propagation channel between the BS 30 and the wireless device 25 and a step (not shown in the figures) of determining the at least one threshold value of the energy measure based on the estimated channel quality value. This is because the threshold value of the energy measure can be adapted based on the channel quality value. For example, the threshold of the energy measure may be lower when the channel quality is good than when the channel quality is poor. For example, the BS 30 may select an energy measure threshold from a plurality of predetermined energy measure thresholds associated with respective different channel quality values.In the example of FIG. 5, it is assumed in a non-limiting manner that the wireless device 25 determines that uplink data is to be transmitted when receiving a trigger signal for uplink transmission from the RAN. Accordingly, the method 50 for exchanging data includes a step S 51 of transmitting a trigger signal for uplink transmission to the wireless device 25 as an indication that uplink data is to be transmitted to the RAN. It is noted that any suitable format for the uplink trigger signal may be used and that selection of a specific format for the uplink trigger signal corresponds to a specific, but non-limiting embodiment of the present disclosure. It is also noted that in some examples, the information regarding at least one threshold value of the energy measure may be included in the trigger signal for an uplink transmission, i.e., steps S 50 and S 51 may correspond to one and the same step.For example, in examples where the BS 30 includes an energy harvesting signal generator 305, the BS 30 may begin transmitting an energy harvesting (RF) signal to the wireless device 25 before transmitting the uplink transmission trigger signal to the wireless device 25.Measure of Stored Electrical Energy and Channel Quality ValueFIG. 6 illustrates a diagram showing steps of an exemplary embodiment of a method 60 for exchanging data implemented by a wireless device 25 of a UE 20. FIG. 7 is a diagram showing respective steps of an exemplary embodiment of a method 70 for exchanging data implemented by a BS 30 of the RAN.As illustrated by FIG. 6, the method 60 of exchanging data includes a step S 60 of determining a threshold value of the energy measure based on an estimated channel quality value of the propagation channel between the RAN and the wireless device 25.The channel quality value may be estimated by the wireless device 25 or by the RAN and transmitted to the wireless device 25. For example, the channel quality value may correspond to one or more of a reference signal received power (RSRP), a received signal strength indicator (RSSI), a reference signal received quality (RSRQ), a channel quality indicator (CQI), a signal to noise ratio (SNR), etc. The present disclosure may use any method known to those skilled in the art for estimating the channel quality value, and the selection of a specific method corresponds to a specific, but non-limiting embodiment of the present disclosure.For example, the wireless device 25 may determine a threshold amount of energy to use using a preconfigured function that outputs a threshold amount of energy in response to an input channel quality value.For example, the wireless device 25 may be preconfigured with an association between a plurality of different energy measure thresholds and respective associated channel quality values, and the wireless device 25 may select the energy measure threshold associated with the estimated channel quality value according to the preconfigured association.For example, the mapping between the plurality of different thresholds of the energy measure and the respective associated channel quality values may be predefined at the wireless device 25 (e.g., indicated by a standard or by a calibration of the wireless device 25).In other examples and as illustrated by FIG. 6, the method 60 of exchanging data may include a previous step S 66 of receiving, from the RAN, the mapping between the plurality of different thresholds of the energy measure and the respective associated channel quality values. In some examples, the wireless device 25 may receive a plurality of these assignments, which may be associated with respective traffic classes (e.g., a priority of uplink data to be transmitted, etc.), respective volumes of uplink data transmitted, etc., for example. In such a case, the wireless device 25 may select one mapping from the plurality of mappings based on the transmission context of the uplink data (traffic class, volume of uplink data, etc.).For example, the at least one mapping between the plurality of different energy measure thresholds and the respective associated channel quality values may be received in system information broadcast by the RAN and / or in a signaling message specifically addressed to the wireless device 25 or to a group of wireless devices including the wireless device 25. In the latter case, the trigger signal for uplink transmission may optionally include an identifier of the wireless device 25 or the group of wireless devices to enable the wireless device 25 to detect that it is the receiver of this information.As illustrated by FIG. 6, the data exchanging method 60 includes a step S 61 of determining that uplink data is to be transmitted by the wireless device 25. All that has been stated for the step S 40 of the data exchanging method 40 in FIG. 4 applies similarly to the step S 61 of the data exchanging method 60 in FIG. 6.In FIG. 6, the step S 60 of determining the threshold value of the energy amount is illustrated as being performed before the step S 61 of determining that uplink data is to be transmitted. As noted above, the order of steps in the figures is provided for illustrative purposes only and is not by any means limiting. For example, the step S 61 of determining the threshold value of the amount of energy may be performed simultaneously with or after the step S 61 of determining that uplink data is to be transmitted. For example, if the wireless device 25 receives a trigger signal for an uplink transmission as an indication from the RAN that uplink data is to be transmitted, then it is possible to estimate the channel quality value using the received trigger signal for an uplink transmission or, optionally, using the received wake-up signal.As illustrated by FIG. 6, the method 60 of exchanging data in response to determining, at step S 61, that uplink data is to be transmitted includes a step S 62 of measuring a measure of the electrical energy stored in the energy storage unit 255. All that has been stated for the step S 41 of the data exchanging method 40 in FIG. 4 applies similarly to the step S 62 of the data exchanging method 60 in FIG. 6.As illustrated by FIG. 6, the method 60 for exchanging data then comprises a step S 63 of evaluating a triggering criterion for an uplink transmission by comparing the measure of the stored electrical energy with the threshold value of the energy measure determined at step S 62. When the triggering criterion for an uplink transmission is verified (reference sign S 63 ain FIG. 6 ), the data exchanging method 60 includes a step S 64 of transmitting uplink data (i.e., all or a part of the uplink data available at the wireless device 25) to the RAN. On the other hand, if the uplink transmission triggering criterion is not verified (reference sign S 63 bin FIG. 6 ), the data exchanging method 60 includes a step S 65 of delaying transmission of the uplink data to the RAN. All that has been stated for the step S 42 of the data exchanging method 40 in FIG. 4 applies similarly to the step S 63 of the data exchanging method 60 in FIG. 6.As discussed above, FIG. 7 illustrates a diagram illustrating corresponding steps of an example embodiment of a method 70 for exchanging data that may be implemented by a BS 30 when the wireless device 25 implements the method 60 for exchanging data illustrated by FIG. 6.As illustrated by FIG. 7, the method 70 of exchanging data includes a step S 70 of transmitting, to the wireless device 25, information regarding at least one threshold of the channel quality value and at least one associated threshold of the amount of energy (received by the wireless device 25 at step S 66). As discussed above, the transmitted information corresponds to, for example, a function that outputs an energy measure threshold in response to an input channel quality value, or an association between a plurality of different energy measure thresholds and respective associated channel quality values, etc. As discussed above, this information may be broadcast in system information and / or transmitted in a signaling message specifically addressed to the wireless device 25 or to a group of wireless devices that includes the wireless device 25.In the example of FIG. 7, it is assumed in a non-limiting manner that the wireless device 25 determines that uplink data is to be transmitted when receiving a trigger signal for uplink transmission from the RAN. Accordingly, the data exchanging method 70 includes a step S 71 of transmitting a trigger signal for uplink transmission to the wireless device 25 as an indication that uplink data is to be transmitted to the RAN. All that has been stated for the step S 51 of the data exchanging method 50 in FIG. 5 similarly applies to the step S 71 of the data exchanging method 70 in FIG. 7.For example, in examples where the BS 30 includes an energy harvesting signal generator 305, the BS 30 may begin transmitting an energy harvesting (RF) signal to the wireless device 25 before transmitting the uplink transmission trigger signal to the wireless device 25.Measure of Stored Electrical Energy and Volume of Uplink DataFIG. 8 illustrates a diagram showing steps of an exemplary embodiment of a method 80 for exchanging data implemented by a wireless device 25 of a UE 20. FIG. 9 illustrates a diagram showing corresponding steps of an example embodiment of a method 90 for exchanging data implemented by a BS 30 of the RAN.As illustrated by FIG. 8, the data exchanging method 80 includes a step S 80 of determining that uplink data is to be transmitted by the wireless device 25. All that has been stated for the step S 40 of the data exchanging method 40 in FIG. 4 applies similarly to the step S 80 of the data exchanging method 80 in FIG. 8.As illustrated by FIG. 8, the method 80 for exchanging data in response to determining, at step S 80, that uplink data is to be transmitted comprises:a step S81 of measuring a measure of the electric energy stored in the energy storage unit 255; anda step S82 of determining a volume of uplink data to be transmitted.All that has been stated for the step S 41 of the data exchanging method 40 in FIG. 4 applies similarly to the step S 81 of the data exchanging method 80 in FIG. 8.The volume of uplink data to be transmitted may take any suitable format that allows it to be compared to a threshold value, for example. For example, the volume of uplink data may correspond to a number of bits, a number of bytes, etc., that the wireless device 25 needs to transmit to the RAN.As illustrated by FIG. 8, the method 80 for exchanging data then comprises a step S 83 of evaluating a triggering criterion for an uplink transmission by comparing the measure of the stored electrical energy with a predetermined threshold value of the energy measure and by comparing the volume of uplink data to be transmitted with at least one predetermined maximum uplink data volume associated with the at least one threshold value of the energy measure. When the triggering criterion for an uplink transmission is verified (reference sign S 83 ain FIG. 8 ), the data exchanging method 80 includes a step S 84 of transmitting uplink data (i.e., all or a part of the uplink data available at the wireless device 25) to the RAN. On the other hand, if the uplink transmission triggering criterion is not verified (reference sign S 83 bin FIG. 8 ), the data exchanging method 80 includes a step S 85 of delaying transmission of the uplink data to the RAN.Thus, the wireless device 25 takes into account both the amount of stored electrical energy and the volume of uplink data before initiating uplink data transmission. For example, to be verified, the triggering criterion for an uplink transmission may require a higher amount of stored electrical energy for transmitting a large volume of uplink data than for transmitting a small volume of uplink data. Thus, in some examples, the wireless device 25 may adjust the threshold amount of energy based on the volume of uplink data to be transmitted, or alternatively may adjust the maximum uplink data volume based on the amount of energy stored in the energy storage unit 255.It should be noted that in some examples, it is also possible to consider other parameters for determining whether the wireless device 25 can initiate the uplink data transmission. For example, the evaluation of the triggering criterion for an uplink transmission may also take into account the channel quality of the propagation channel between the RAN and the wireless device 25. For example, the triggering criterion for an uplink transmission may be considered unverified as soon as the channel quality value is below a predetermined minimum channel quality value. On the other hand, if the channel quality value is above the predetermined minimum channel quality value, then the wireless device may further evaluate the amount of stored electrical energy and the uplink data volume to be transmitted, as discussed above, to determine whether the uplink data transmission may be initiated.In some examples, the evaluation of the triggering criterion for an uplink transmission may use a preconfigured mapping between a plurality of different thresholds of the energy measure and respective associated different maximum uplink data volumes.For example, the mapping between the plurality of different thresholds of the energy measure and the respective associated maximum uplink data volumes may be predefined at the wireless device 25 (e.g., indicated by a standard or by a calibration of the wireless device 25).In other examples and as illustrated by FIG. 8, the method 80 for exchanging data may include a previous step S 86 of receiving, from the RAN, the mapping between the plurality of different thresholds of the energy measure and the respective associated maximum uplink data volumes. In some examples, the wireless device 25 may receive a plurality of these assignments, e.g., associated with respective traffic classes (e.g., a priority of uplink data to be transmitted, etc.), respective channel quality values, etc. In such a case, the wireless device 25 may select one mapping from the plurality of mappings based on the transmission context of the uplink data (traffic class, channel quality value, etc.).For example, the at least one mapping between the plurality of different thresholds of the energy measure and the respective associated maximum uplink data volumes may be received in system information broadcast by the RAN and / or in a signaling message specifically addressed to the wireless device 25 or to a group of wireless devices including the wireless device 25. In the latter case, the trigger signal for uplink transmission may optionally include an identifier of the wireless device 25 or the group of wireless devices to enable the wireless device 25 to detect that it is the receiver of this information.Table 1 illustrates an example of an association between the plurality of threshold values of the energy measure and the plurality of respective maximum uplink data volumes. Table 1 Table 1EL1DV1EL2DV2EL3DV3In the example of Table 1, the various threshold values of the energy measure are defined by various values EL 1, EL 2, and EL 3, so that 0<EL 1<EL 2<EL 3. The different maximum uplink data volumes are defined by different values DV 1, DV 2 and DV 3, so that: 0<DV 1<DV 2<DV 3. For example, if EL denotes the measured amount of electrical energy stored in the energy storage unit 255, and DV denotes the determined volume of uplink data to be transmitted by the wireless device 25:if EL< EL1, then the triggering criterion for an uplink transmission is not verified, regardless of the volume of uplink data to be transmitted,If EL1< EL< EL2, then the maximum uplink data volume is DV1 and the uplink transmission triggering criterion is verified if DV< DV1 (and not verified if DV> DV1),If EL2< EL< EL3, then the maximum uplink data volume is DV2 and the uplink transmission triggering criterion is verified if DV< DV2 (and not verified if DV> DV2),If EL> EL3, then the maximum uplink data volume is DV3 and the triggering criterion for uplink transmission is verified if DV<DV3 (and not verified if DV>DV3).Thus, the triggering criterion for an uplink transmission is verified, for example, when the volume of uplink data to be transmitted is smaller than the maximum uplink data volume associated with the largest threshold value of the amount of energy being smaller than the amount of stored electrical energy. Of course, other formats may be contemplated for mapping between a plurality of energy measure thresholds and a plurality of maximum uplink data volumes, and other decision strategies may also be contemplated using such mapping.As mentioned above, if the trigger criterion for an uplink transmission is not verified, the uplink data transmission is delayed (step S85). For example, the uplink data transmission may be delayed by a predetermined delay that begins when it is determined that the uplink data transmission is to be delayed. In such a case, the uplink data transmission can be initiated as soon as the predetermined delay has expired without the triggering criterion for an uplink transmission having to be evaluated again.In other examples and as illustrated by FIG. 8, the evaluation of the triggering criterion for an uplink transmission may be repeatedly performed, for example at each subsequent uplink transmission opportunity, until the triggering criterion for an uplink transmission is verified. For example, the uplink data transmission may be initiated as soon as the amount of stored electrical energy is greater than the predetermined threshold value of the amount of energy. In some examples, the uplink transmission triggering criterion may also be verified at some time, regardless of the amount of electrical energy stored, to ensure that the uplink data transmission is not delayed infinitely. For example, the triggering criterion for an uplink transmission may be verified when the delay introduced for performing the transmission of the uplink data reaches a predetermined maximum delay. According to another example, the triggering criterion for an uplink transmission may be verified when the number of uplink burst opportunities reaches a predetermined maximum number of uplink burst opportunities.In alternative examples, the uplink data to be transmitted may be discarded if the triggering criterion for an uplink transmission is still not verified after a predetermined maximum delay or after a predetermined maximum number of discarded uplink transmission opportunities.As discussed above, FIG. 9 illustrates a diagram illustrating corresponding steps of an example embodiment of a method 90 for exchanging data that may be implemented by a BS 30 when the wireless device 25 implements the method 80 for exchanging data illustrated by FIG. 8.As illustrated by FIG. 9, the method 90 for exchanging data includes a step S 90 of transmitting, to the wireless device 25, information regarding at least one threshold value of the amount of energy and at least one maximum uplink data volume (received by the wireless device 25 at step S 86) to be used during the evaluation of the triggering criterion for an uplink transmission. As discussed above, the transmitted information corresponds to, for example, an association between a plurality of threshold values of the energy measure and a plurality of maximum uplink data volumes. As discussed above, this information may be broadcast in system information and / or transmitted in a signaling message specifically addressed to the wireless device 25 or to a group of wireless devices that includes the wireless device 25.In some examples, the method 90 for exchanging data may include: a step (not shown in the figures) of estimating a (current or future) level of utilization of the BS 30; and a step (not shown in the figures) of adjusting, based on the estimated level of utilization, the information regarding at least one threshold of the amount of energy and at least one maximum uplink data volume transmitted to the wireless device 25. The level of utilization represents the amount of traffic that the BS 30 must handle. For example, the degree of utilization may correspond to a total number of UEs 20 having data for exchanging with the BS 30, a total amount of uplink data to be received by the BS 30 from multiple UEs 20, etc. For example, the maximum uplink data volumes may be lower when the degree of utilization is high (e.g., near network congestion) than when the degree of utilization is low. Alternatively, or in combination, the thresholds of the energy measure may be higher when the level of utilization is high (e.g., near congestion) than when the level of utilization is low. For example, the BS 30 may select an assignment between a plurality of threshold values of the energy measure and a plurality of maximum uplink data volumes from a plurality of predetermined assignments associated with respective different levels of utilization.In the example of FIG. 9, it is assumed in a non-limiting manner that the wireless device 25 determines that uplink data is to be transmitted when receiving a trigger signal for uplink transmission from the RAN. Accordingly, the method 90 for exchanging data includes a step S 91 of transmitting a trigger signal for uplink transmission to the wireless device 25 as an indication that uplink data is to be transmitted to the RAN.For example, in examples where the BS 30 includes an energy harvesting signal generator 305, the BS 30 may begin transmitting an energy harvesting (RF) signal to the wireless device 25 before transmitting the uplink transmission trigger signal to the wireless device 25. All that has been stated for the step S 51 of the data exchanging method 50 in FIG. 5 similarly applies to the step S 91 of the data exchanging method 90 in FIG. 9.It is emphasized that the present disclosure is not limited to the above exemplary embodiments. Variations of the above exemplary embodiments also fall within the scope of the present disclosure.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Cited Non-Patent LiteratureReport TR 38.848 V18.0.0

[0003]

Claims

A method (40) for exchanging data in a wireless communication system, the method being implemented by a wireless device (25) of the wireless communication system, the wireless device comprising an energy harvesting unit (254) configured to convert ambient energy into electrical energy stored in an energy storage unit (255) of the wireless device, the wireless device further comprising a communication unit (253) configured to exchange data with a radio access network (RAN) of the wireless communication system, the method comprising: - (S41) measuring a measure of the electrical energy stored in the energy storage unit, in response to determining that uplink data is to be sent to the RAN, (S42) evaluating a triggering criterion for an uplink transmission by comparing the measure of the stored electrical energy with a predetermined threshold value of the energy measure, in response to the triggering criterion for an uplink transmission being verified: (S43) transmitting uplink data to the RAN, in response to the triggering criterion for an uplink transmission not being verified: (S44) delaying the transmission of the uplink data to the RAN.The method (40) of claim 1, wherein the threshold amount of energy is determined based on information received from the RAN regarding at least one threshold amount of energy.The method (40) of claim 2, wherein the information regarding at least one threshold of the energy measure is received in system information broadcast by the RAN and / or in a signaling message specifically addressed to the wireless device or to a group of wireless devices including the wireless device.The method (40) of any preceding claim, wherein the transmission of the uplink data to the RAN is delayed until the triggering criterion for an uplink transmission is verified.The method (40) of any preceding claim, wherein the triggering criterion for an uplink transmission is verified if the amount of stored electrical energy is greater than the predetermined threshold amount of energy.The method (40) according to any of the preceding claims, wherein the triggering criterion for an uplink transmission is verified regardless of the amount of stored electrical energy: - if the delay introduced for performing the transmission of the uplink data reaches a predetermined maximum delay, or - if the number of discarded uplink transmission opportunities reaches a predetermined maximum number of discarded uplink transmission opportunities.The method (40) of any preceding claim, wherein the wireless device determines that uplink data is to be transmitted based on receiving a trigger signal for an uplink transmission from the RAN.The method (40) of any preceding claim, wherein the energy harvesting unit is a radio unit configured to convert a received radio frequency signal into electrical energy.A wireless device (25) comprising at least one memory and at least one processor configured to perform a method (40) according to any preceding claim.A user equipment (UE) (20) comprising a wireless device according to claim 9.A method (50) for exchanging data in a wireless communication system, the method being implemented by a base station (BS) (30) of a radio access network (RAN) of the wireless communication system, the BS being configured to exchange data with a wireless device (25) comprising an energy harvesting unit (254) configured to convert ambient energy into electrical energy stored in an energy storage unit (255) of the wireless device, the method comprising transmitting (S50) to the wireless device (25) information relating to at least one threshold value of the energy measure.The method (50) of claim 11, comprising estimating a channel quality value of a propagation channel between the BS and the wireless device and determining the at least one threshold value of the energy measure based on the estimated channel quality value.The method (50) of any of claims 11 to 12, comprising transmitting (S51) a trigger signal for an uplink transmission to the wireless device as an indication that uplink data is to be transmitted by the wireless device (25) to the RAN.The method (50) of claim 13, comprising beginning to transmit an energy harvesting signal to the wireless device (25) prior to transmitting the trigger signal for an uplink transmission to that wireless device.The method (50) of any of claims 11 to 14, wherein the information regarding at least one threshold of the energy measure is broadcast in system information and / or transmitted in a signaling message specifically addressed to the wireless device or to a group of wireless devices including the wireless device.A base station (BS) (30) comprising at least one memory and at least one processor configured to perform a method (40) according to any of claims 11 to 15.A wireless communication system comprising at least one base station (30) according to claim 16 and at least one user equipment (20) according to claim 9.A computer program product (252, 302) comprising instructions which, when executed by at least one processor, configure the at least one processor to perform a method (40) according to any one of claims 1 to 8 or a method (50) according to any one of claims 11 to 15.A computer readable storage medium comprising instructions which, when executed by at least one processor, configure the at least one processor to perform a method (40) according to any one of claims 1 to 8 or a method (50) according to any one of claims 11 to 15.

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