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

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 a channel quality value.

Description

Technical area

[0001] The present disclosure relates to wireless communication systems, and more particularly, to methods and apparatus for enabling a very low power wireless device to determine whether to initiate an uplink data transmission based on at least one channel quality value. 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 ambient (A-loT) 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 channel quality value of a propagation channel and to use the channel quality value to determine whether the wireless device can proceed with uplink data transmission or whether the uplink data transmission should be delayed instead.

[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: - Estimating a channel quality value of a propagation channel between the RAN and the wireless device, - Evaluating a trigger criterion for an uplink transmission by comparing the estimated channel quality value with a predetermined threshold value of the channel quality value, - in response to the trigger criterion for an uplink transmission being verified: transmitting uplink data to the RAN, - in response to the trigger criterion for an uplink transmission not being verified: Delay the transmission of the uplink data to the RAN.

[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 of the method according to the first aspect, the threshold value of the channel quality value is determined based on information received from the RAN regarding at least one threshold value of the channel quality value.

[0011] In some embodiments of the method according to the first aspect, the information regarding at least one threshold of the channel quality value 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.

[0012] In some embodiments of the method according to the first aspect, the transmission of the uplink data to the RAN is delayed until the trigger criterion for an uplink transmission is verified.

[0013] In some embodiments of the method according to the first aspect, the trigger criterion for an uplink transmission is verified when the channel quality value is greater than the predetermined threshold value of the channel quality value.

[0014] In some embodiments of the method according to the first aspect, the trigger criterion for an uplink transmission is verified regardless of the channel quality value: - if the delay introduced to perform the transmission of the uplink data reaches a predetermined maximum delay or - when the number of rejected uplink transmission opportunities reaches a specified maximum number of rejected uplink transmission opportunities.

[0015] In some embodiments of the method according to the first aspect, the maximum delay or the maximum number of rejected uplink transmission opportunities is determined based on information received from the RAN.

[0016] In some embodiments of the method according to the first aspect, the information regarding the maximum delay or the maximum number of missed uplink transmission opportunities 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.

[0017] In some embodiments of the method according to the first aspect, a repetition pattern is used to transmit the uplink data when the trigger criterion for an uplink transmission is verified regardless of the channel quality value.

[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 signal 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 that is stored in an energy storage unit of the wireless device, the method comprising transmitting, to the wireless device, information regarding at least one threshold value of the channel quality value.

[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 regarding at least one threshold value of the channel quality value 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.

[0025] In some embodiments, the method according to the fourth aspect comprises transmitting, to the wireless device, information regarding a maximum delay or a maximum number of missed uplink transmission opportunities.

[0026] In some embodiments of the method according to the fourth aspect, the information regarding the maximum delay or the maximum number of missed uplink transmission opportunities 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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 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.

[0032] 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

[0033] 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.

[0034] 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

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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).

[0045] As through Fig. 2, the wireless device 25 also includes an energy harvesting unit 254 and a wireless device energy storage unit 255.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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 at the RAN side according to any of the embodiments disclosed herein.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] As discussed above, the above disclosure aims to enable a wireless device 25 to decide whether an uplink data transmission can be initiated by directly or indirectly considering a channel quality value of a propagation channel between the RAN and the wireless device 25. Considering the channel quality value can be used, for example, to avoid initiating the uplink data transmission when the channel quality is poor, which could result in a failed uplink data transmission. Thus, considering the channel quality value can reduce the likelihood of failed uplink transmissions for A-IoT devices.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] As through Fig. 4, the method 40 for exchanging data includes a step S41 of estimating a channel quality value of a propagation channel between the RAN and 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.

[0063] 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.

[0064] Likewise, the estimated channel quality value may take any suitable format, in particular any suitable format that allows it to be compared, for example, with a threshold value.

[0065] As through Fig. 4, the method 40 for exchanging data comprises a step S42 of evaluating a trigger criterion for an uplink transmission by comparing the estimated channel quality value with a predetermined threshold value of the channel quality value.

[0066] If the trigger criterion for an uplink transmission is verified (reference sign S42a in Fig. 4), the method 40 for exchanging data comprises a step S43 of transmitting uplink data (ie, all or part of the uplink data available at the wireless device 25) to the RAN. If, however, the trigger criterion for an uplink transmission is not verified (reference sign S42b in Fig. 4), the method 40 for exchanging data comprises a step S44 of delaying the transmission of the uplink data to the RAN.

[0067] Thus, the wireless device 25 considers the channel quality value before initiating the uplink data transmission to evaluate whether the channel quality is sufficient for the uplink data transmission to be likely to succeed. For example, the trigger criterion for an uplink transmission is verified if the estimated channel quality value is greater than the predetermined threshold channel quality value (which, in such a case, corresponds to a minimum channel quality value required for the uplink data transmission). If the channel quality is not considered sufficient, the uplink data transmission is delayed, e.g., at least until the subsequent uplink transmission opportunity, to wait for more favorable channel quality conditions.

[0068] It is 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 trigger criterion for an uplink transmission may also consider the volume of uplink data to be transmitted, the amount of electrical energy stored in the energy storage unit 255, etc. More generally, the trigger criterion for an uplink transmission may consider any parameter relevant to assessing whether the uplink data transmission is likely to be successful, with the channel quality value being an important parameter in the context of A-IoT devices.Thus, in some examples, the trigger criterion for an uplink transmission may be considered verified if the channel quality value is greater than the predetermined threshold of the channel quality value and if one or more other conditions are verified, for example, if the level of stored electrical energy is greater than a predetermined threshold of the energy measure, etc.

[0069] For example, the threshold channel quality value may be predefined at the wireless device 25 (e.g., specified by a standard or by calibration of the wireless device 25).

[0070] In other examples and as Fig. 4, the method 40 for exchanging data may include a prior step S45 of receiving, from the RAN, information regarding at least one threshold of the channel quality value, and the threshold of the channel quality value 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 channel quality value that may be used by the wireless device 25. For example, the received information may consist of a single threshold of the channel quality value that the wireless device 25 may directly use in evaluating the trigger criterion for an uplink transmission. In other examples, the received information may include a plurality of different thresholds of a channel quality value, e.g., associated with respective traffic classes (e.g.,a priority of uplink data to be transmitted, etc.), respective amounts of electrical energy stored in the energy storage unit 255, respective volumes of uplink data to be transmitted, etc. In such a case, the wireless device 25 may select a channel quality value threshold from the plurality of received channel quality value thresholds based on the transmission context of the uplink data (traffic class, amount of stored electrical energy, volume of uplink data, etc.).

[0071] For example, the information regarding at least one threshold of the channel quality value 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 including 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.

[0072] As stated 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, which begins when it is determined that the uplink data transmission should be delayed. In such a case, the uplink data transmission is initiated once the predetermined delay has elapsed, without the need to re-evaluate the trigger criterion for an uplink transmission.

[0073] In other examples and as shown by Fig. As illustrated in Figure 4, the evaluation of the trigger criterion for an uplink transmission may be performed repeatedly, for example, on each subsequent uplink transmission occasion, until the trigger criterion for an uplink transmission is verified. For example, the uplink data transmission may be initiated on an uplink transmission occasion as soon as the estimated channel quality value becomes greater than the predetermined threshold of the channel quality value.

[0074] In some examples, the trigger criterion for an uplink transmission may be verified at some point, regardless of the estimated channel quality value, to ensure that the uplink data transmission is not delayed indefinitely. For example, the trigger criterion for an uplink transmission may be verified when the delay introduced to perform the transmission of the uplink data reaches a predetermined maximum delay. According to another example, the trigger criterion for an uplink transmission may be verified when the number of missed uplink transmission opportunities reaches a predetermined maximum number of missed uplink transmission opportunities. Thus, such specifications 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 missed uplink transmission opportunities.

[0075] For example, the maximum delay or the maximum number of missed uplink transmission opportunities may be predefined at the wireless device 25 (e.g., specified by a standard or by a calibration of the wireless device 25).

[0076] In other examples, the maximum delay or the maximum number of missed uplink transmission opportunities may be determined based on information received from the RAN.

[0077] For example, the maximum delay (or the maximum number of missed uplink transmission opportunities) is received in system information broadcast by the RAN and / or in a signaling message (which may be, for example, a trigger signal for an uplink transmission or a wake-up signal) specifically addressed to the wireless device 25 or to a group of wireless devices including the wireless device 25. For example, the information regarding the maximum delay (or the information regarding the maximum number of missed uplink transmission opportunities) may be received with the information regarding the at least one channel quality value (at step S45) or separately from the information regarding the at least one channel quality value.

[0078] If the trigger criterion for an uplink transmission is verified regardless of the channel quality value (e.g., if the introduced delay reaches the maximum delay or if the number of missed uplink transmission opportunities reaches the maximum number of missed uplink transmission opportunities), then the uplink data transmission could be initiated while the channel quality value is lower than the predetermined threshold channel quality value (i.e., while the channel quality may be poor). In preferred embodiments, a repetition pattern is used to transmit the uplink data. In other words, the same uplink data may be transmitted multiple times, possibly only when the estimated channel quality value is determined to be lower than the threshold channel quality value.This introduces a degree of redundancy, which increases the possibility that the uplink data will be received correctly by the RAN.

[0079] In alternative examples, the uplink data to be transmitted may be discarded if the trigger criterion for an uplink transmission is still not verified after a predetermined maximum delay or after a predetermined maximum number of rejected uplink transmission opportunities.

[0080] 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.

[0081] As through Fig. 5, the method 50 for exchanging data includes a step S50 of transmitting, to the wireless device 25, information regarding at least one threshold of the channel quality value (received by the wireless device 25 at step S45) to be used by the wireless device 25 to evaluate the trigger criterion for an uplink transmission. As discussed above, this information may, for example, 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.

[0082] In some cases, as discussed above, the information regarding a maximum delay or a maximum number of missed uplink transmission opportunities may also be transmitted during a step S50 with the information regarding at least one threshold value of the channel quality value or separately from step S50.

[0083] 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 S51 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 at least one threshold value of the channel quality value may be included in the trigger signal for an uplink transmission, ie, steps S50 and S51 may correspond to one and the same step.

[0084] 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.

[0085] 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: - (S40) Determine that uplink data should be sent to the RAN, - (S41) estimating a channel quality value of a propagation channel between the RAN and the wireless device (25), - (S42) evaluating a trigger criterion for an uplink transmission by comparing the estimated channel quality value with a predetermined threshold value of the channel quality value, - in response to the trigger criterion for an uplink transmission being verified: (S42a) transmitting uplink data to the RAN, - in response to the trigger criterion for an uplink transmission not being verified: (S42b) Delaying the transmission of the uplink data to the RAN. [2] The method (40) of claim 1, wherein the threshold value of the channel quality value is determined based on information received from the RAN regarding at least one threshold value of the channel quality value. [3] The method (40) of claim 2, wherein the information regarding at least one threshold of the channel quality value 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. [4] Method (40) according to one of the preceding claims, wherein the transmission of the uplink data to the RAN is delayed until the trigger criterion for an uplink transmission is verified. [5] Method (40) according to one of the preceding claims, wherein the trigger criterion for an uplink transmission is verified if the channel quality value is greater than the predetermined threshold value of the channel quality value. [6] Method (40) according to one of the preceding claims, wherein the trigger criterion for an uplink transmission is verified regardless of the channel quality value: - if the delay introduced to perform the transmission of the uplink data reaches a predetermined maximum delay or - when the number of rejected uplink transmission opportunities reaches a specified maximum number of rejected uplink transmission opportunities. [7] The method (40) of claim 6, wherein the maximum delay or the maximum number of missed uplink transmission opportunities is determined based on information received from the RAN. [8] The method (40) of any one of claims 6 to 7, wherein a repetition pattern is used to transmit the uplink data when the trigger criterion for an uplink transmission is verified regardless of the channel quality value. [9] The method (40) of any preceding claim, wherein the wireless device determines that uplink data is to be transmitted based on receiving a signaling message signal from the RAN. [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 that is 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 channel quality value. [13] The method (50) of claim 12, wherein the information regarding at least one threshold value of the channel quality value 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. [14] The method (50) of any one of claims 12 to 13, comprising transmitting to the wireless device information regarding a maximum delay or a maximum number of missed uplink transmission opportunities. [15] The method (50) of claim 14, wherein the information regarding the maximum delay or the maximum number of missed uplink transmission opportunities 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. [16] The method (50) of any one of claims 12 to 15, comprising transmitting (S51) a signaling message to the wireless device as an indication that uplink data is to be transmitted by the wireless device (25) to the RAN. [17] Base station (BS - base station) (30), comprising at least one memory and at least one processor configured to carry out a method (40) according to one of claims 12 to 16. [18] A wireless communication system comprising at least one base station (30) according to claim 17 and at least one user device (20) according to claim 11. [19] 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 16. [20] 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 16.

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