Method and apparatus for performing an uplink transmission on an ambient IoT device by adapting uplink data packet sizes to 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 adapt uplink data packet sizes to an amount of stored electrical energy.

Description

Technical area

[0001] The present disclosure relates to wireless communication systems, and more particularly, to methods and apparatus for enabling a wireless device that relies on ambient energy harvesting to adapt uplink data packet sizes to an amount of stored electrical energy. background

[0002] The Internet of Things (IoT) enables various devices to connect to the internet to send data, receive instructions, or both. Tens of billions of IoT devices are already deployed, and the global number of IoT devices is expected to grow rapidly. Thus, massive connectivity is required. However, powering these billions of IoT devices presents a critical challenge, and deploying power cables or regularly replacing / recharging batteries is not a practical solution.

[0003] 3GPP (Third Generation Partnership Project) is currently investigating new IoT technologies to open up new markets within 3GPP systems. These technologies can provide orders of magnitude higher connection counts and / or device density than existing 3GPP IoT technologies, and can provide orders of magnitude lower complexity and power consumption than existing 3GPP technologies, such as narrow-band IoT (NB-IoT) and long-term evolution-machine-type communications (LTE-MTC). Specifically, 3GPP currently defines A-IoT (Ambient-IoT) technologies (see, for example, technical report TR 38.848 V18.0).0) aiming to enable very low-power IoT devices, which could be either battery-less devices without energy storage capability (performing backscatter transmission) or devices with an energy storage that does not need to be manually replaced or recharged (performing wireless ambient energy harvesting (EH) from one or more energy sources).

[0004] By "very low-power" or "A-IoT" devices, the authors mean devices with 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 that have 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 can be generated internally by the device or backscattered on an externally provided carrier wave).

[0005] Typically, such A-IoT devices have limited energy storage, and the use of stored electrical energy must be optimized to reduce the likelihood of uplink data transmission failure. Failed data transmissions lead to wasted uplink resources and increased electrical power consumption and must be avoided. Brief description

[0006] The 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.

[0007] For this purpose, it is proposed to evaluate a level of electrical energy stored in a wireless device and to use the level of stored electrical energy to adjust the sizes of uplink data packets transmitted to the radio access network (RAN).

[0008] 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 that is 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 sent to the RAN: - Measuring a measure of the electrical energy stored in the energy storage unit, - Transmitting the uplink data to the RAN in one or more uplink data packets having sizes determined based on the amount of stored electrical energy.

[0009] In some embodiments, the method according to the first aspect may further comprise one or more of the following optional features, which are contemplated either alone or in a technically possible combination.

[0010] In some embodiments, the method according to the first aspect comprises determining, based on the amount of stored electrical energy, a maximum uplink data packet size for transmitting uplink data to the RAN, wherein the sizes of the one or more transmitted uplink data packets are determined based on the determined maximum uplink data packet size.

[0011] In some embodiments, the method according to the first aspect comprises, in response to determining that the amount of uplink data to be transmitted is greater than the determined maximum uplink data packet size, splitting the uplink data to be transmitted into a plurality of uplink data packets having sizes corresponding to the determined maximum uplink data packet size.

[0012] In some embodiments of the method according to the first aspect, information received from the RAN is used in determining uplink data packet sizes based on the level of stored electrical energy.

[0013] In some embodiments of the method according to the first aspect, the information comprises an association between at least one threshold value of the energy measure and at least one maximum uplink data packet size associated therewith.

[0014] In some embodiments of the method according to the first aspect, the information is received in system information broadcast by the RAN or in a signaling message specifically addressed to the wireless device or to a group of wireless devices including the wireless device.

[0015] In some embodiments of the method according to the first aspect, when the uplink data is transmitted in a plurality of uplink data packets, each uplink data packet of the plurality of uplink data packets is transmitted with an indication of remaining uplink data packets pending transmission.

[0016] In some embodiments of the method according to the first aspect, the indication regarding remaining uplink data packets pending transmission corresponds to an indication of the number of remaining uplink data packets pending transmission or an indication of whether uplink data packets pending transmission remain.

[0017] In some embodiments of the method according to the first aspect, the indication regarding remaining uplink data packets pending transmission is transmitted via L1 signaling and / or L2 signaling.

[0018] In some embodiments of the method according to the first aspect, the wireless device determines that uplink data should be transmitted based on receiving a signaling message from the RAN.

[0019] 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.

[0020] 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 one of the embodiments of the first aspect.

[0021] According to a third aspect, the present disclosure relates to a user equipment (UE) comprising a wireless device according to any one of the embodiments of the present disclosure.

[0022] 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 regarding the determination of uplink data packet sizes based on a measure of electrical energy stored in the energy storage unit.

[0023] In some embodiments, the method according to the fourth aspect may further comprise one or more of the following optional features, which are contemplated either alone or in a technically possible combination.

[0024] In some embodiments of the method according to the fourth aspect, the information relating to the determination of uplink data packet sizes based on the level of stored electrical energy comprises an association between at least one threshold value of the energy measure and at least one maximum uplink data packet size associated therewith.

[0025] In some embodiments of the method according to the fourth aspect, the information regarding the determination of the uplink data packet sizes based on the amount of stored electrical energy 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.

[0026] In some embodiments, the method according to the fourth aspect includes controlling the information to be transmitted to the wireless device based on one or more environmental parameters.

[0027] In some embodiments of the method according to the fourth aspect, the information to be transmitted to the wireless device is controlled based on a load level of the BS.

[0028] In some embodiments, the method according to the fourth aspect comprises transmitting a signaling message to the wireless device as an indication that uplink data is to be transmitted by the wireless device to the RAN.

[0029] In some embodiments, the method according to the fourth aspect comprises beginning to transmit an energy harvesting signal to the wireless device prior to transmitting the signaling message to that wireless device.

[0030] In some embodiments, the method according to the fourth aspect comprises receiving an uplink data packet from the wireless device and an associated indication of remaining uplink data packets pending transmission, and generating an energy harvesting signal for the wireless device in response to the indication indicating that there is at least one remaining uplink data packet pending transmission.

[0031] 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 one of the embodiments of the fourth aspect.

[0032] According to a sixth aspect, the present disclosure relates to a wireless communication system comprising at least one base station according to one of the embodiments of the present disclosure and at least one user device according to one of the embodiments of the present disclosure.

[0033] According to a seventh aspect, the present disclosure relates to a computer program product comprising instructions that, when executed by at least one processor, configure the at least one processor to perform a method for exchanging data according to any 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.

[0034] According to an eighth aspect, the present disclosure relates to a (non-transitory) computer-readable storage medium comprising instructions that, when executed by at least one processor, configure the at least one processor to perform a method for transmitting control messages according to any one of the embodiments of the present disclosure. Short description of the drawings

[0035] The invention will be better understood upon reading the following description, given as a non-limiting example, with reference to the figures in which: - Fig. 1: schematic representations of various possible topologies of a wireless communication system, - Fig. 2: a schematic representation of an example of a wireless device, - Fig. 3: a schematic representation of an example of a BS, - Fig. 4 and Fig. 5: Flowcharts illustrating examples of methods for exchanging data implemented by a wireless device of a UE and a BS, respectively.

[0036] In these figures, reference numerals that are identical from one figure to another indicate identical or similar elements. For clarity, the elements shown are not to scale unless expressly stated otherwise. Detailed description

[0037] The following detailed description with reference to the figures is intended to be a description of various configurations and is not intended to represent the only configurations in which the presently described concepts may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of 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, while this disclosure may use 3GPP terminology, e.g., from 5G NR, to explain embodiments herein, this should not be seen as limiting the scope of the present disclosure.

[0038] In general, all terms used herein should be interpreted according to their usual meaning in the relevant technical field, unless another meaning is clearly indicated and / or clear from the context in which it is used. All references to an element, facility, component, means, step, etc., should be interpreted as referring to at least one occurrence of the element, facility, component, means, step, etc., unless expressly stated otherwise.Likewise, 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 part 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 precede another step. Furthermore, steps depicted in a figure that are surrounded by a dashed line are to be considered optional for the embodiment depicted in that figure. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, as appropriate.Likewise, any advantage of one embodiment may apply to any other embodiment, and vice versa. Other objects, features, and advantages of the included embodiments will become apparent from the following description.

[0039] Fig. Figure 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 depicts a RAN of the wireless communication system used to exchange data with UEs 20 via radio signals. The RAN can, for example, send data to the UEs 20 (DL - downlink), such as data received from a core network (CN - core network, not shown in the figures). The RAN can also receive data from the UEs 20 (UL - uplink), and this data can be forwarded to the CN.

[0040] In the Fig. In the example illustrated in Figure 1, the RAN includes a base station (BS) 30. Of course, the RAN may include more than one BS 30 to expand the coverage area of the wireless communication system. Each of these BSs may be referred to as an 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(s) implemented.

[0041] In the Fig. In the example illustrated in Figure 1, only one UE 20 is shown, which includes a wireless device 25 that provides the UE 20 with wireless connectivity to the RAN of the wireless communication system. Part a) of Fig. Figure 1 schematically illustrates an example in which the UE 20 exchanges data (payload and control data) directly with a BS 30 of the RAN (referred to as Topology 1 in TR 38.848 V18.0.0). Part b) of Fig. Figure 1 schematically illustrates an example in which the UE 20 exchanges data (payload and control data) indirectly 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 can be, for example, a relay, an IAB (integrated access and backhaul) node, another UE 20, a repeater, a reconfigurable intelligent surface (RIS), etc.

[0042] Fig. 2 schematically illustrates an example of a wireless device 25 suitable for implementing any method discussed in the present disclosure and performed on a UE 20. Essentially, the wireless device 25 corresponds to a device that provides wireless connectivity to 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 that has a peak power consumption of less than 1 mW, or even less than 100 µW, or even less than 10 µW.

[0043] Such a wireless device 25 may be incorporated in a UE 20 as shown 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, a smart sensor, a smart meter, smart glasses, a (manned or unmanned) vehicle, a Global Positioning System device, etc., or any other device capable of executing applications that require exchanging data with remote receivers via the wireless device 25.

[0044] As through 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 non-volatile memory (magnetic hard drive, 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.

[0045] As through Fig. As illustrated in Figure 2, the wireless device 25 also includes a (wireless) communication unit 253 configured to exchange data (directly or indirectly) with BSs 30 of the RAN using radio signals. The communication unit 253 may implement one or more wireless communication protocols and may, for example, be a 3G, 4G, 5G, NR, WiFi, WiMax, etc., transceiver or the like. In preferred embodiments, the (wireless) communication unit 253 includes a 5G NR wireless communication unit.

[0046] As discussed above, in some examples, communication unit 253 may include neither DL (downlink) nor UL (uplink) amplification capability (the UL transmission is backscattered on an externally provided carrier wave). In other examples, communication unit 253 may include DL and / or UL amplification (the UL transmission may be generated internally by the wireless device or backscattered on an externally provided carrier wave).

[0047] As through Fig. 2, the wireless device 25 also includes an energy harvesting unit 254 and a wireless device energy storage unit 255.

[0048] The energy storage unit 255 may be any type of electrical 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 features 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.

[0049] The energy harvesting unit 254 is configured to convert ambient energy into electrical energy, which is stored in the energy storage unit 255. By "ambient energy," the authors mean energy from energy sources external to the wireless device 25 that is 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 autonomously without the need to manually replace or recharge the energy storage unit 255. The energy harvesting unit 254 can, for example, collect energy from various energy sources, including solar, heat, motion or vibration, radio frequency (RF), etc.

[0050] In preferred embodiments, the energy harvesting unit 254 comprises at least one radio unit configured to convert RF signals into electrical energy, which is stored in the energy storage unit 255. These RF signals may, for example, be external RF signals, i.e., RF signals that do not originate from within 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 in the vicinity of the wireless device 25.Alternatively, or in combination, the RF signals may originate from within the wireless communication system, for example, from BSs 30 of the RAN that may transmit an energy harvesting (RF) signal to wireless (A-IoT) devices 25 within their coverage area, and / or from devices separate from the BSs 30 but deployed to enable energy harvesting on the wireless (A-IoT) devices 25 of the wireless communication system. In some examples, if RF signals are used to feed electrical energy to the energy storage unit 255, the energy harvesting unit 254 may be included in the (wireless) communication unit 253.

[0051] Fig. 3 schematically illustrates an example of a BS 30 suitable for implementing a method discussed in the present disclosure as well as performed by the RAN.

[0052] As through 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 non-volatile 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 RAN side according to any of the embodiments disclosed herein.

[0053] As through Fig. 3, the BS 30 also includes a wireless communication unit 303 configured to exchange data with UEs 20 using radio signals, and in particular with (wireless) communication units 253 of wireless devices 25 included in these UEs 20. The wireless communication unit 303 may, for example, be a 3G, 4G, 5G, NR, WiFi, WiMax, etc. transceiver or the like. In preferred embodiments, the wireless communication unit 303 of the BS 30 includes a 5G NR transceiver. In some examples, the wireless communication unit 303 may also transmit carrier waves to the wireless devices 25, performing uplink transmissions with backscatter.

[0054] As through Fig. As illustrated in Figure 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.

[0055] As through 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 into 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 choice of a specific energy harvesting (RF) signal format is a specific and non-limiting embodiment of the present disclosure. As noted above, such energy harvesting (RF) signals may, where appropriate, alternatively or in combination, be generated by other devices separate from the RAN's BSs 30.

[0056] As discussed above, the above disclosure aims to enable a wireless device 25 to adjust uplink data packet sizes based on the amount of electrical energy stored in its energy storage unit 255. Taking the amount of stored electrical energy into account to adjust the sizes of the uplink data packets makes it possible to reduce the likelihood of an uplink data packet failing to transmit. This is because it makes it possible to ensure that the amount of stored electrical energy is sufficient to transmit a given uplink data packet, and in some cases, it can ensure that it is transmitted with sufficient transmit power to enable the RAN to decode it.

[0057] The authors now present examples of signaling and decision strategies that can be implemented to achieve a higher probability of successful uplink data transmissions by the wireless device 25 and thereby reduce waste of uplink resources and energy consumption.

[0058] Fig. 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 respective steps of an exemplary embodiment of a method 50 for exchanging data implemented by a BS 30 of the RAN.

[0059] As through Fig. 4, the method 40 for exchanging data includes a step S40 of determining that uplink data should be sent by the wireless device 25.

[0060] In some examples, step S40 may consist of detecting that uplink data is available at the UE 20 and is to be transmitted by the wireless device 25 to the RAN.

[0061] Alternatively, or in combination, the wireless device 25 may determine that uplink data should be transmitted to the RAN when it detects an upcoming UL transmission opportunity. For example, a UL transmission opportunity corresponds to UL resources that the wireless device 25 may use. For example, such UL resources may be 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 assigned to the wireless device 25, such as scheduling request (SR) resources.

[0062] Alternatively, or in combination therewith, an uplink data transmission may be initiated by the RAN. In such examples, step S40 may include receiving an uplink transmission trigger signal 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, upon an upcoming UL transmission opportunity. Of course, such an uplink data transmission should only be initiated if uplink data is available at the UE 20 or can be collected by the UE in response to receiving the uplink transmission trigger signal from the RAN.In the present disclosure, the authors assume, in a non-limiting manner, that uplink data is available or can be collected by the UE 20, and focus on other conditions that the wireless device 25 can consider to decide whether to initiate uplink data transmission.

[0063] To reduce its electrical power consumption, the wireless device 25 may be placed in a sleep mode. In such a case, the wireless device 25 must transition to an active mode to be able to perform the uplink data transmission. Such a transition may be triggered by the RAN sending a wake-up signal to the wireless device 25. In such a case, the uplink transmission trigger signal may correspond to the wake-up signal transitioning the wireless device 25 from a sleep mode to an active mode, or it may be transmitted by the RAN after the RAN transmits a wake-up signal to the wireless device 25.

[0064] It is noted that in some examples, it is also possible to consider other parameters for determining whether to transmit uplink data. For example, the wireless device 25 may also consider the channel quality of the propagation channel between the RAN and the wireless device 25 before initiating an uplink data transmission. For example, the wireless device 25 may determine that uplink data may be transmitted if the channel quality value is above a predetermined minimum channel quality value. Conversely, if the channel quality value is below the predetermined minimum channel quality value, the wireless device 25 may decide to delay or abort the transmission of uplink data to the RAN.

[0065] 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, if wireless device 25 receives an uplink transmission trigger signal as an indication from the RAN that uplink data should be transmitted, it is then possible to estimate the channel quality value using the received uplink transmission trigger signal or, if appropriate, the received wake-up signal. The channel quality value may also be estimated using another reference signal transmitted by the RAN.

[0066] As through Fig. 4, the method 40 for exchanging data includes, in response to determining at step S40 that uplink data is to be transmitted, a step S41 of measuring a measure of the electrical energy stored in the energy storage unit 255. The measure of stored electrical energy may be measured using any method known to those skilled in the art, and the selection of a specific method corresponds to a specific, but non-limiting, embodiment of the present disclosure. Also, the measured measure of electrical energy may take any suitable format that allows it to be compared, for example, to a threshold value. For example, the measure of stored electrical energy may correspond to an energy value expressed, for example, in joules or watt-hours, or a percentage indicating the charge of the energy storage unit 255 (where, for example,0% indicates that the energy storage unit 255 is empty, and 100% indicates that the energy storage unit 255 is fully charged), etc.

[0067] As through Fig. 4, the method 40 for exchanging data includes a step S43 of transmitting the uplink data to the RAN in one or more uplink data packets having sizes determined based on the amount of stored electrical energy.

[0068] For example and as in Fig. As illustrated in Figure 4, the sizes of the one or more uplink data packets may be determined based on a maximum uplink data packet size determined based on the amount of stored electrical energy at step S42. The sizes of the one or more uplink data packets to be transmitted may then be determined at step S43 based on the determined maximum uplink data packet size determined at step S42, thereby ensuring that each uplink data packet to be transmitted has a size corresponding to the determined maximum packet size.For example, if the amount of uplink data to be transmitted is greater than the determined maximum uplink data packet size, the wireless device 25 may divide the uplink data to be transmitted into a plurality of uplink data packets such that each resulting uplink data packet has a size smaller than the determined maximum uplink data packet size. When the uplink data is divided into a plurality of uplink data packets based on the amount of stored electrical energy, these uplink data packets are preferably transmitted separately, e.g., during separate uplink transmission occasions, to enable the energy harvesting unit 254 to harvest electrical energy between the transmission of two consecutive uplink data packets.

[0069] For example, in determining, by the wireless device 25, uplink data packet sizes based on the amount of stored electrical energy, predefined information (e.g., specified by a standard or by the calibration of the wireless device 25) or information received from the RAN is used.

[0070] For example, the information used to determine uplink data packet sizes may correspond to a preconfigured function that outputs a maximum uplink data packet size in response to an input amount of electrical energy stored in the energy storage unit 255.

[0071] In other examples, the information used to determine the uplink data packet sizes may correspond to a mapping between at least one energy metric threshold and at least one associated maximum uplink data packet size. In some cases, the information may correspond to a mapping between a plurality of different energy metric thresholds and respective different maximum uplink data packet sizes. Thus, wireless device 25 may select the maximum uplink data packet size by comparing the measured level of stored electrical energy to the plurality of energy metric thresholds of the mapping.

[0072] Table 1 provides an example of a mapping between a plurality of energy measure thresholds and a plurality of respective maximum uplink data packet sizes. Table 1 Schwellenwert des Energiemaßes Maximale Uplink-Datenpaketgröße EL1 DPS1 EL2 DPS2 EL3 DPS3

[0073] In the example of Table 1, the different thresholds of the energy measure are defined by different values EL1, EL2, and EL3, such that: 0 < EL1 < EL2 < EL3. The different maximum uplink data packet sizes are defined by different values DPS1, DPS2, and DPS3, such that: 0 < DPS1 < DPS2 < DPS3. For example, if the measured amount of electrical energy stored in the energy storage unit 255 is denoted by EL, the following applies: - if EL < EL1, then it is possible to delay or abort the transmission of uplink data, - if EL1 < EL < EL2, then the maximum uplink data packet size is DPS1, - if EL2 < EL < EL3, then the maximum uplink data packet size is DPS2, - if EL > EL3, then the maximum uplink data packet size is DPS3.

[0074] Thus, the maximum uplink data packet size used can be the one associated with the largest energy metric threshold that is smaller than the stored electrical energy metric. Of course, other formats for mapping between a plurality of energy metric thresholds and a plurality of maximum uplink data packet sizes can be considered, and other decision strategies can also be considered when using such a mapping.

[0075] In the Fig. 4, it is assumed that the information used to determine the uplink data packet sizes (e.g., a mapping between a plurality of energy measure thresholds and a plurality of maximum uplink data packet sizes) is received from the RAN at step S44 of the method 40 for exchanging data.

[0076] For example, the received information may include a single mapping between a plurality of energy metric thresholds and a plurality of maximum uplink data packet sizes. In other examples, the received information may include a plurality of such mappings, which may be associated, for example, with respective traffic classes (e.g., a priority of uplink data to be transmitted, etc.), with respective channel quality values, etc. In such a case, the wireless device 25 may select one mapping from the plurality of received mappings based on the transmission context of the uplink data (traffic class, channel quality value, etc.).

[0077] For example, the information used to determine uplink data packet sizes 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 that includes the wireless device. In the latter case, the trigger signal for an 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 recipient of this information.

[0078] In some examples, when splitting the uplink data to be transmitted into a plurality of uplink data packets based on the amount of stored electrical energy, the wireless device 25 may then optionally transmit each uplink data packet with an indication of remaining uplink data packets pending transmission. In other words, when transmitting an uplink data packet that is the result of splitting the entire uplink data to be transmitted, the wireless device 25 indicates whether that uplink data packet is followed by at least one other uplink data packet resulting from that same split. Such an indication may, if appropriate, be used by the RAN, for example, to trigger the generation of an energy harvesting signal toward the wireless device 25 to enable it to harvest electrical energy for the transmission of the subsequent uplink data packet.

[0079] For example, the indication regarding remaining uplink data packets pending transmission is transmitted via L1 signaling and / or L2 signaling. However, any suitable format may be used to transmit this indication, and the choice of a specific format corresponds to a specific, but non-limiting, embodiment of the present disclosure.

[0080] For example, the indication regarding remaining uplink data packets waiting to be transmitted corresponds to an indication of the number of remaining uplink data packets waiting to be transmitted. In such a case, the RAN knows how many uplink data packets are expected to be received after the current one. For example, 3 bits can be used to provide such an indication, indicating up to 7 remaining uplink data packets to be received.

[0081] In other examples, the indication regarding remaining uplink data packets awaiting transmission is an indication of whether there are any remaining uplink data packets awaiting transmission. In such a case, the RAN only knows whether the current uplink data packet will be followed by another. Thus, a single bit can be used to provide such an indication, where, for example, a value of '1' indicates that there are more uplink data packets to be received, and a value of '0' indicates that the current uplink data packet is the last one.

[0082] As discussed above, Fig. 5 is a diagram illustrating corresponding steps of an exemplary embodiment of a method 50 for exchanging data that may be implemented by a BS 30 when the wireless device 25 executes the method 40 for exchanging data that may be implemented by Fig. 4 is implemented.

[0083] As through Fig. 5, the method 50 for exchanging data includes a step S51 of transmitting, to the wireless device 25, information regarding the determination of uplink data packet sizes based on a measure of electrical energy stored in the energy storage unit 255 (e.g., a mapping between a plurality of threshold values of the energy measure and a plurality of maximum uplink data packet sizes). 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 including the wireless device 25.

[0084] In some examples and as Fig. 5, the method 50 for exchanging data may include an optional step S50 of controlling the information related to determining uplink data packet sizes to be transmitted to the wireless device 25 based on one or more environmental parameters (channel quality value, load level, etc.).

[0085] For example, step S50 may include estimating a (current or future) utilization level of the BS 30 and adjusting, based on the estimated utilization level, the information relating to the determination of uplink data packet sizes transmitted to the wireless device 25. The utilization level represents the amount of traffic that the BS 30 must handle. For example, the utilization level may correspond to a total number of UEs 20 having data to exchange 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 packet sizes may be smaller when the utilization level is high (e.g., close to network congestion) than when the utilization level is low.For example, the BS 30 may select a mapping between a plurality of energy measure thresholds and a plurality of maximum uplink data packet sizes from a plurality of predetermined mappings associated with respective different utilization levels.

[0086] As noted above, other environmental parameters may also be considered alternatively to, or in combination with, the load factor. For example, the maximum uplink data packet sizes may be smaller when the channel quality is poor than when the channel quality is good (e.g., to enable wireless device 25 to increase transmit power when the channel quality is poor).

[0087] In the example of Fig. 5, it is assumed in a non-limiting manner that the wireless device 25 determines that uplink data should be transmitted when it receives an uplink transmission trigger signal from the RAN. Accordingly, the method 50 for exchanging data includes a step S52 of transmitting an uplink transmission trigger signal to the wireless device 25 as an indication that uplink data should be transmitted to the RAN. It is noted that any suitable format may be used for the uplink transmission trigger signal, and that the selection of a specific format for the uplink transmission 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 the determination of the uplink data packet sizes may be included in the trigger signal for an uplink transmission, ie, steps S51 and S52 may correspond to one and the same step.

[0088] 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 trigger signal for an uplink transmission to the wireless device 25 (in Fig. 5 not shown).

[0089] As discussed above, in some embodiments, the wireless device 25 may receive with an uplink data packet an indication of remaining uplink data packets pending transmission. In the non-limiting example of Fig. 5, it is assumed that such an indication is transmitted by the wireless device 25, and the method 50 for exchanging data includes a step S53 of receiving an uplink data packet from the wireless device 25, in which the BS 30 evaluates whether there are any remaining uplink data packets pending transmission.

[0090] In response to determining that at least one remaining data packet pending transmission is present at the wireless device 25 (reference symbol S53a in Fig. 5), step S53 is repeated. In the non-limiting example of Fig. 5, the BS 30 further begins to generate an energy harvesting signal for the wireless device 25 in a step S54. However, if there are no further uplink data packets pending transmission at the wireless device 25 (reference symbol S53b in Fig. 5), steps S53 and S54 are not repeated.

[0091] It is emphasized that the present disclosure is not limited to the above exemplary embodiments. Variants of the above exemplary embodiments also fall within the scope of the present disclosure.

Claims

[1] 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 that is 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, in response to determining that uplink data is to be sent to the RAN: - (S41) measuring a measure of the electrical energy stored in the energy storage unit, - (S43) transmitting the uplink data to the RAN in one or more uplink data packets having sizes determined based on the amount of stored electrical energy. [2] The method (40) of claim 1, comprising determining (S42) a maximum uplink data packet size for transmitting uplink data to the RAN based on the amount of stored electrical energy, wherein the sizes of the one or more transmitted uplink data packets are determined based on the determined maximum uplink data packet size. [3] The method (40) of claim 2, comprising, in response to determining that the amount of uplink data to be transmitted is greater than the determined maximum uplink data packet size, splitting the uplink data to be transmitted into a plurality of uplink data packets having sizes corresponding to the determined maximum uplink data packet size. [4] A method (40) according to any one of the preceding claims, wherein the determination of uplink data packet sizes based on the level of stored electrical energy uses information received from the RAN. [5] The method (40) of claim 4, wherein the information comprises an association between at least one threshold value of the energy measure and at least one maximum uplink data packet size associated therewith. [6] The method (40) of any one of claims 4 to 5, wherein the information is received in system information broadcast by the RAN or is received in a signaling message specifically addressed to the wireless device or to a group of wireless devices including the wireless device. [7] The method (40) of any preceding claim, wherein, when the uplink data is transmitted in a plurality of uplink data packets, each uplink data packet of the plurality of uplink data packets is transmitted with an indication of remaining uplink data packets pending transmission. [8] The method (40) of claim 7, wherein the indication regarding remaining uplink data packets pending transmission corresponds to an indication of the number of remaining uplink data packets pending transmission or an indication of whether uplink data packets pending transmission remain. [9] Method (40) according to one of claims 7 to 8, wherein the indication regarding remaining uplink data packets pending transmission is transmitted via L1 signaling and / or L2 signaling. [10] A wireless device (25) comprising at least one memory and at least one processor configured to perform a method (40) according to any one of the preceding claims. [11] A user equipment (UE) (20) comprising a wireless device according to claim 10. [12] 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 (S51) to the wireless device (25) information relating to determining uplink data packet sizes based on a measure of electrical energy stored in the energy storage unit. [13] The method (50) of claim 12, wherein the information relating to the determination of uplink data packet sizes based on the level of stored electrical energy comprises an association between at least one threshold value of the energy measure and at least one maximum uplink data packet size associated therewith. [14] The method (50) of any one of claims 12 to 13, wherein the information relating to the determination of uplink data packet sizes based on the level of stored electrical energy 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. [15] The method (50) of any one of the preceding claims 12 to 14, comprising controlling (S50) the information to be transmitted to the wireless device based on one or more environmental parameters. [16] The method (50) of claim 15, wherein the information to be transmitted to the wireless device is controlled based on a load level of the BS. [17] The method (50) of any one of claims 12 to 16, comprising receiving (S53) an uplink data packet from the wireless device and an associated indication of remaining uplink data packets pending transmission, and generating (S54) an energy harvesting signal for the wireless device in response to the indication indicating that there is at least one remaining uplink data packet pending transmission. [18] Base station (BS - base station) (30), comprising at least one memory and at least one processor configured to carry out a method (50) according to one of claims 12 to 17. [19] A wireless communication system comprising at least one base station (30) according to claim 18 and at least one user device (20) according to claim 11. [20] A computer program product (252, 302) comprising instructions that, 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 9 or a method (50) according to any one of claims 12 to 17. [21] A computer-readable storage medium comprising instructions that, 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 9 or a method (50) according to any one of claims 12 to 17.

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