Method and device for reducing signaling overhead for triggering uplink transmissions at an ambient-iot device

Abstract

The present disclosure relates to methods and devices for reducing signaling overhead for triggering uplink transmissions at a user equipment, UE (20), which includes a wireless device (25) having an energy harvesting unit (254) which stores electrical energy in an energy storage unit (255) of the wireless device.

Description

Method and device for reducing signaling overhead for triggering uplink transmissions at an ambient-loT deviceTechnical field

[0001] The present disclosure relates to wireless communication systems and relates more specifically to methods and devices for reducing signaling overhead for triggering uplink transmissions at an ambient-loT device.Background

[0002] The internet of things (loT) allows various devices to connect to the internet to send data, receive instructions, or both. Tens of billions of loT devices are already deployed and the global number of loT devices is expected to increase rapidly. Thus, massive connectivity is needed. However, powering these billions of loT devices is a critical challenge, and deploying power cables or regularly replacing / recharging batteries is not a viable solution.

[0003] 3GPP (Third Generation Partnership Project) is investigating new loT technologies to open new markets within 3GPP systems, whose number of connections and / or device density can be orders of magnitude higher than existing 3GPP loT technologies, and which can provide complexity and power consumption orders-of-magnitude lower than existing 3GPP technologies such as narrow-band-loT (NB-loT) and long-term evolution-machine- type communications (LTE-MTC). More specifically, 3GPP is currently defining Ambient- loT (A-loT) technologies (see e.g., the technical report TR 38.848 V18.0.0) aiming at enabling ultra-low power consumption loT devices, which could be either batteryless devices with no energy storage capability (performing backscattering transmission) or devices with energy storage that do not need to be replaced or recharged manually (performing wire-free energy harvesting (EH) from one or more energy sources).

[0004] By “ultra-low power consumption” devices, or “A-loT” devices, we mean devices having a peak power consumption lower than 1 mW, or even lower than 100 pW or lower than 10 pW. For instance, Ambient-loT currently aims at enabling A-loT devices having the following characteristics:- around 1 pW peak power consumption with energy storage, with neither downlink (DL) nor uplink (UL) amplification in the device (the device’s LIL transmission is backscattered on a carrier wave provided externally), below a few hundred pW peak power consumption with energy storage, with DL and / or UL amplification in the device (the device’s UL transmission may be generated internally by the device or be backscattered on a carrier wave provided externally).

[0005] In some cases, such A-loT devices may only initiate an uplink transmission when triggered so by the radio access network, RAN. However, the signaling burden on the RAN, for triggering uplink transmissions by the A-loT devices, will increase drastically as the number of A-loT devices deployed increases.Summary

[0006] The present disclosure aims at improving the situation. In particular, the present disclosure aims at addressing at least some of the limitations of the prior art discussed above. In particular, the present disclosure aims at proposing a solution for enabling reducing the signaling overhead in relation with wireless devices such as A-loT devices.

[0007] For that purpose, it is proposed that the RAN transmits an uplink transmission triggering signal to a wireless device, which indicates that the wireless device may initiate an uplink transmission, and to include in the uplink transmission triggering signal an information regarding characteristics of the triggered uplink transmission. Hence, the uplink transmission triggering signal includes other information in addition to the indication that the wireless device may initiate an uplink transmission, which information needs not to be transmitted in a separate signaling message, thereby reducing signaling overhead.

[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, wherein the wireless device comprises 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, wherein the method comprises:- receiving an uplink transmission triggering signal from the RAN, wherein the uplink transmission triggering signal includes an information regarding at least one characteristic of the triggered uplink transmission,- transmitting uplink data to the RAN, wherein the transmission of uplink data is controlled based on the information regarding at least one characteristic of the triggered uplink transmission.

[0009] In some embodiments, the method according to the first aspect can further comprise one or more of the following optional features, considered either alone or in any technically possible combination.

[0010] In some embodiments of the method according to the first aspect, the information regarding at least one characteristic of the triggered uplink transmission includes an indication of whether the uplink transmission triggering signal triggers recurrent uplinktransmissions.

[0011] In some embodiments of the method according to the first aspect, the information regarding at least one characteristic of the triggered uplink transmission includes an indication of whether the triggered uplink transmission is a periodic uplink transmission.

[0012] In some embodiments of the method according to the first aspect, if the triggered uplink transmission is a periodic uplink transmission, the information regarding at least one characteristic of the triggered uplink transmission includes an indication of a periodicity of the triggered uplink transmission.

[0013] In some embodiments, the method according to the first aspect comprises interrupting recurrent uplink transmissions triggered by the uplink transmission triggering signal in response to receiving an uplink transmission interrupting signal from the RAN.

[0014] In some embodiments of the method according to the first aspect, the uplink transmission interrupting signal is received via L1 signaling and / or L2 signaling.

[0015] In some embodiments of the method according to the first aspect, the uplink transmission interrupting signal is received in a medium access control, MAC, control element, CE, or in downlink control information, DCI.

[0016] In some embodiments of the method according to the first aspect, the uplink transmission triggering signal is a wake-up signal that transitions the wireless device from a sleep mode to an active mode.

[0017] In some embodiments of the method according to the first aspect, the energy harvesting unit is a radio unit configured to convert a received radiofrequency signal into electrical energy.

[0018] 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 carry out a method according to any one of the embodiments of the first aspect.

[0019] 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.

[0020] 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, wherein the BS is configured to exchange data with a wireless device which comprises an energy harvesting unit configured to convert ambient energy into electrical energy that is stored in an energy storage unit of the wireless device, wherein the method comprises transmitting to the wireless device an uplink transmission triggering signal, wherein theuplink transmission triggering signal includes an information regarding at least one characteristic of the triggered uplink transmission.

[0021] In some embodiments, the method according to the fourth aspect can further comprise one or more of the following optional features, considered either alone or in any technically possible combination.

[0022] In some embodiments of the method according to the fourth aspect, the information regarding at least one characteristic of the triggered uplink transmission includes an indication of whether the uplink transmission triggering signal triggers recurrent uplink transmissions.

[0023] In some embodiments of the method according to the fourth aspect, the information regarding at least one characteristic of the triggered uplink transmission includes an indication of whether the triggered uplink transmission is a periodic uplink transmission.

[0024] In some embodiments of the method according to the fourth aspect, if the triggered uplink transmission is a periodic uplink transmission, the information regarding at least one characteristic of the triggered uplink transmission includes an indication of a periodicity of the triggered uplink transmission.

[0025] In some embodiments, the method according to the fourth aspect comprises transmitting an uplink transmission interrupting signal to the wireless device to interrupt recurrent uplink transmissions.

[0026] In some embodiments of the method according to the fourth aspect, the uplink transmission interrupting signal is transmitted via L1 signaling and / or L2 signaling.

[0027] In some embodiments of the method according to the fourth aspect, the uplink transmission interrupting signal is transmitted in a medium access control, MAC, control element, CE, or in downlink control information, DCI.

[0028] In some embodiments of the method according to the fourth aspect, the uplink transmission triggering signal is a wake-up signal that transitions the wireless device from a sleep mode to an active mode.

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

[0030] 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 carry out a method according to any one of the embodiments of the fourth aspect.

[0031] According to a sixth aspect, the present disclosure relates to a wireless communication system comprising at least one base station according to any one of theembodiments of the present disclosure and at least one user equipment according to any one of the embodiments of the present disclosure.

[0032] According to a seventh aspect, the present disclosure relates to a computer program product comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method for exchanging data according to any one of the embodiments of the present disclosure. The computer program product can use any programming language, and can be in the form of source code, object code, or in any intermediate form between source code and object code, such as in a partially compiled form, or in any other desirable form.

[0033] According to an eighth aspect, the present disclosure relates to a (non-transitory) computer-readable storage medium comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method for transmitting control messages according to any one of the embodiments of the present disclosure.Brief description of figures

[0034] The invention will be better understood upon reading the following description, given as an example that is in no way limiting, and made in reference to the figures which show:Figure 1 : schematic representations of different possible topologies of a wireless communication system,Figure 2: a schematic representation of an example of a wireless device,Figure 3: a schematic representation of an example of a BS,- Figures 4 and 5: flow charts illustrating examples of methods for exchanging data implemented by a wireless device of a UE and a BS, respectively.

[0035] In these figures, references identical from one figure to another designate identical or analogous elements. For reasons of clarity, the elements shown are not to scale, unless explicitly stated otherwise.Detailed description

[0036] The detailed description set forth below, with reference to the figures, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein 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 instance, although 3GPP terminology, from e.g., 5G NR, may be used in this disclosure to exemplify embodiments herein, this should not be seen as limiting the scope of the present disclosure.

[0037] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. Also, the order of steps of any methods disclosed herein, in particular in the figures, is provided only for illustration purposes and is not meant to limit the present disclosure which may be applied with the same steps executed in a different order and / or with all or part of the steps executed in parallel or jointly, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Also, in a figure, steps represented surrounded by a dashed line are to be considered as optional for the embodiment represented in this figure. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

[0038] Figure 1 represents schematically an example of wireless communication system, which may be for example a 5G NR wireless communication system. More specifically, figure 1 represents a RAN of the wireless communication system, which is used exchange data with UEs 20 via radio signals. For example, the RAN may send data to the UEs 20 (downlink, DL), for instance data received from a core network (ON, not represented in the figures). The RAN may also receive data from the UEs 20 (uplink, UL), which data may be forwarded to the ON.

[0039] In the example illustrated by figure 1 , the RAN comprises one base station, BS, 30. Of course, the RAN may comprise more than one BS 30 to increase the coverage of the wireless communication system. Each of these BSs may be referred to as NB, eNodeB (or eNB), gNodeB (or gNB, in the case of a 5G NR wireless communication system), an access point or the like, depending on the wireless communication standard(s) implemented.

[0040] In the example illustrated by figure 1 , only one UE 20 is represented, 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 figure 1 represents schematically an example in which the UE 20 exchanges data (useful data 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 figure 1 represents schematically an example in which the UE 20 exchanges data (useful data and control data) indirectly with a BS 30 of the RAN, via one or more intermediate nodes 31 (referred to asTopology 2 in TR 38.848 V18.0.0). Each intermediate node 31 may be e.g., a relay, an integrated access and backhaul (IAB) node, another UE 20, a repeater, a reconfigurable intelligent surface (RIS), etc.

[0041] Figure 2 represents schematically an example of a wireless device 25 suitable for implementing any method, discussed in the present disclosure, performed at a UE 20. Basically, the wireless device 25 corresponds to an apparatus that provides wireless connectivity with the RAN of the wireless communication system, and that can be used to exchange data with said RAN. The wireless device 25 is for example an A-loT device, i.e., a wireless device having a peak power consumption lower than 1 mW, or even lower than 100 pW, or even lower than 10 pW.

[0042] Such a wireless device 25 may be included in a UE 20, as illustrated by figure 2. The UE 20 may for instance be a cellular 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 (loT) equipment, like a wireless camera, a smart sensor, a smart meter, smart glasses, a vehicle (manned or unmanned), a global positioning system device, etc., or any other equipment that may run applications that need to exchange data with remote recipients, via the wireless device 25.

[0043] As illustrated by figure 2, the wireless device 25 comprises one or more processors 250 and one or more memories 251 . The one or more processors 250 may include for instance a central processing unit (CPU), a digital signal processor (DSP), a field- programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc. The one or more memories 251 may include any type of computer readable volatile and nonvolatile memories (magnetic hard disk, solid-state disk, 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-code 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 at a UE’s side, according to any one of the embodiments disclosed herein.

[0044] As illustrated by figure 2, the wireless device 25 comprises also 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 instance be a 3G, 4G, 5G, NR, WiFi, WIMax, etc. transceiver or the like. In preferred embodiments, the (wireless) communication unit 253 comprises a 5G NR wireless communication unit.

[0045] As discussed above, the communication unit 253 may comprise in some examples neither downlink (DL) nor uplink (UL) amplification capabilities (the UL transmission isbackscattered on a carrier wave provided externally). In other examples, the communication unit 253 may comprise DL and / or UL amplification (the UL transmission may be generated internally by the wireless device or be backscattered on a carrier wave provided externally).

[0046] As illustrated by figure 2, the wireless device 25 comprises also an energy harvesting unit 254 and an energy storage unit 255 of the wireless device.

[0047] The energy storage unit 255 may be any type of electrical energy accumulator, and may comprise e.g., one or more capacitors, one or more batteries, etc. The energy storage unit 255 is used to provide electrical energy to the other equipment of the wireless device 25 which require electrical energy, such as the one or more processors 250, the one or more memories 251 and, in some examples, the (wireless) communication unit 253.

[0048] The energy harvesting unit 254 is configured to convert ambient energy into electrical energy that is stored in the energy storage unit 255. By “ambient energy” we mean energy from energy sources that are external to the wireless device 25, which is received at the wireless device 25 without any wires between the energy sources and the wireless device 25. Hence, the energy harvesting unit 254 is such that the wireless device 25 may operate in an autonomous manner, without having to replace or recharge manually the energy storage unit 255. The energy harvesting unit 254 may for example collect energy from various energy sources including solar, thermal, motion or vibration, radiofrequency (RF), etc.

[0049] In preferred embodiments, the energy harvesting unit 254 comprises at least a radio unit configured to convert RF signals into electrical energy that is stored in the energy storage unit 255. These RF signals may for instance be external RF signals, i.e., RF signals which do not originate from within the wireless communication system itself but from RF sources which are external to 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 thereof, the RF signals may originate from within the wireless communication system, for example from BSs 30 of the RAN which may transmit an energy harvesting (RF) signal to (A-loT) wireless devices 25 in their coverage, and / or from equipment separate from the BSs 30 but deployed to enable energy harvesting at the (A-loT) wireless devices 25 of the wireless communication system. In some examples, when RF signals are used to collect electrical energy into the energy storage unit 255, the energy harvesting unit 254 may be included in the (wireless) communication unit 253.

[0050] Figure 3 represents schematically an example of a BS 30 suitable to implement any method, discussed in the present disclosure, performed by the RAN.

[0051] As illustrated by figure 3, the BS 30 comprises one or more processors 300 and one or more memories 301. The one or more processors 300 may include for instance 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 memories (magnetic hard disk, solid-state disk, 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 programcode 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’s side, according to any one of the embodiments disclosed herein.

[0052] As illustrated by figure 3, the BS 30 comprises also a wireless communication unit 303, configured to exchange data with UEs 20 using radio signals, and more specifically with (wireless) communication units 253 of wireless devices 25 included in these UEs 20. The wireless communication unit 303 may for instance 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 comprises a 5G NR transceiver. In some examples, the wireless communication unit 303 may also transmit carrier waves to the wireless devices 25 which perform uplink backscattering transmissions.

[0053] As illustrated by figure 3, the BS 30 may comprise also, in some examples, 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 optical) and / or wireless.

[0054] As illustrated by figure 3, the BS 30 may comprise also, in some examples, an energy harvesting signal generator 305, which generates energy harvesting (RF) signals which enable wireless devices 25 in its coverage to collect electrical energy in their energy storage units 255, via their energy harvesting units 254. The energy harvesting (RF) signals may take any suitable form enabling 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 consists in a specific and non-limitative embodiment of the present disclosure. As mentioned above, when present, such energy harvesting (RF) signals may alternatively, or in combination thereof, be generated by other equipment separate from BSs 30 of the RAN.

[0055] As discussed above, the present disclosure aims at reducing the signaling burden on the RAN for handling wireless devices 25 such as A-loT devices.

[0056] For that purpose, it is proposed that the RAN transmits an uplink transmissiontriggering signal to a wireless device 25, which indicates that the wireless device 25 may initiate an uplink transmission, and to include in the uplink transmission triggering signal an information regarding characteristics of the triggered uplink transmission. Hence, the uplink transmission triggering signal includes other information in addition to the indication that the wireless device 25 may initiate an uplink transmission, which information needs not to be transmitted in a separate signaling message, thereby reducing signaling overhead.

[0057] We now present non-limitative examples of embodiments of the present disclosure.

[0058] Figure 4 represents a diagram showing steps of an exemplary embodiment of a method 40 for exchanging data, which is implemented by a wireless device 25 of a UE 20. Figure 5 represents a diagram showing corresponding steps of an exemplary embodiment of a method 50 for exchanging data, which is implemented by a BS 30 of the RAN.

[0059] As illustrated by figure 4, the method 40 for exchanging data comprises a step S40 of receiving an uplink transmission triggering signal from the RAN.

[0060] The purpose of the uplink transmission triggering signal is to indicate to the wireless device 25 that it can initiate an uplink data transmission.

[0061] For example, the wireless device 25, upon receiving an uplink transmission triggering signal from the RAN, may decide to transmit uplink data in an upcoming uplink transmission occasion. For example, an uplink transmission occasion corresponds to uplink resources that the wireless device 25 can use. For example, such uplink resources may be e.g., contention-based uplink resources such as random-access channel (RACH) uplink resources or configured grant (CG) uplink resources, etc. In other examples, such uplink resources may be allocated specifically to the wireless device 25, such as scheduling request, SR, resources.

[0062] To reduce its electrical energy consumption, the wireless device 25 may be placed in a sleep mode. In such a case, the wireless device 25 needs to transition to an active mode to be able to perform the uplink data transmission. Such a transition may be triggered by the RAN, by sending a wake-up signal to the wireless device 25. In such a case, the uplink transmission triggering signal may correspond to the wake-up signal which transitions the wireless device 25 from a sleep mode to an active mode, or it may be transmitted by the RAN after it has transmitted a wake-up signal to the wireless device 25. Using a same signal for the wake-up signal and the uplink transmission triggering signal further reduces the signaling overhead for the RAN, compared to using separate signals.

[0063] As discussed above, the uplink transmission triggering signal includes an information regarding at least one characteristic of the triggered uplink transmission. Hence, the uplink transmission triggering signal carries also information which is used by thewireless device 25 to control the transmission of uplink data.

[0064] For example, the information included in the uplink transmission triggering signal may include an indication of a traffic class of the uplink data to be included in the triggered uplink transmission. For example, the traffic class may correspond to a priority level of the uplink data to be transmitted (e.g., enabling the wireless device 25 to transmit only uplink data having a priority level which matches the indicated priority level), to a latency requirement (quality of service, QoS) of the uplink data to be transmitted (e.g., enabling the wireless device 25 to transmit only uplink data having a latency requirement which matches the indicated latency requirement), etc.

[0065] Alternatively, or in combination thereof, the information included in the uplink transmission triggering signal may include an indication of the uplink transmission occasions that the wireless device 25 may use to transmit uplink data. It should be noted that, in other examples, the uplink transmission occasions may be known beforehand by the wireless device 25 (e.g., received previously from the RAN, for example in system information broadcasted by the RAN or in a signaling message addressed specifically to the wireless device 25 or to a group of wireless devices which includes said wireless device 25), such that they need not to be indicated in the uplink transmission triggering signal.

[0066] Alternatively, or in combination thereof, the information included in the uplink transmission triggering signal may include an indication of whether the uplink transmission triggering signal triggers recurrent uplink transmissions. In other words, the information may indicate whether the uplink transmission triggering signal triggers a plurality of uplink transmissions or a single uplink transmission. If the information indicates that the uplink transmission triggering signal triggers recurrent uplink transmissions, this means that the wireless device 25 may initiate subsequent recurrent uplink transmissions without having to receive beforehand a further uplink transmission triggering signal from the RAN. This further reduces the signaling overhead for the RAN since the RAN needs to transmit only a single uplink transmission triggering signal to the wireless device 25 to trigger a plurality of recurrent uplink data transmissions.

[0067] For example, the indication regarding whether the uplink transmission triggering signal triggers recurrent uplink transmissions may consist in a single bit, with e.g., a value T indicating that the uplink transmission triggering signal triggers recurrent uplink transmissions and a value ‘0’ indicating that the uplink transmission triggering signal does not trigger recurrent uplink transmissions (e.g., it triggers a single uplink transmission).

[0068] Of course, other formats may be considered for such an indication, and the choice of a specific format consists in a specific but non-limitative embodiment of the presentdisclosure. Also, the information may also, in some cases, include additional information in relation to e.g., the triggered recurrent uplink transmissions. For example, when recurrent uplink transmissions are triggered, the uplink transmission triggering signal may in some examples include an indication on e.g., a maximum number of triggered uplink transmissions (limiting the number of uplink transmissions that the wireless device 25 may initiate uplink transmissions without receiving a further uplink transmission triggering signal), a maximum duration during which the wireless device 25 may initiate uplink transmissions without receiving a further uplink transmission triggering signal, etc.

[0069] In some examples, the triggered recurrent uplink transmissions may be periodic. For example, the periodicity of such uplink transmissions may be preconfigured at the wireless device 25, for example predefined (e.g., specified by a standard) or previously received from the RAN (e.g., in system information broadcasted by the RAN). In other examples, the periodicity of the triggered uplink transmissions may be indicated directly in the uplink transmission triggering signal.

[0070] In the following, we consider in a non-limitative manner that the uplink transmission triggering signal includes at least an indication of whether the uplink transmission triggering signal triggers recurrent uplink transmissions.

[0071] As illustrated by figure 4, the wireless device 25 therefore comprises a step S41 of evaluating the information included in the uplink transmission triggering signal (received in step S40) to determine whether recurrent (e.g., periodical) uplink transmissions are triggered by the RAN.

[0072] In response to determining that the uplink transmission triggering signal does not trigger recurrent uplink transmissions (reference S41a in figure 4), the method 40 for exchanging data comprises a single step S42 of transmitting uplink data. In turn, in response to determining that the uplink transmission triggering signal triggers recurrent uplink transmissions (reference S41 b in figure 4), the method 40 for exchanging data comprises a step S43 of transmitting uplink data which is repeated recurrently (e.g., periodically).

[0073] In the non-limitative example of figure 4, the method 40 for exchanging data comprises a step S44 of evaluating whether the recurrent uplink transmissions should be interrupted. If the wireless device 25 determines that the recurrent uplink transmissions need to be interrupted (reference S44a in figure 4), then the wireless device 25 interrupts the recurrent uplink transmissions. In turn, if the wireless device 25 determines that the recurrent uplink transmissions do not need to be interrupted (reference S44b in figure 4), then the wireless device 25 may repeat the step S43 of transmitting uplink data to the RAN.

[0074] For example, as discussed above, the uplink transmission triggering signal mayinclude information limiting in time the recurrent uplink transmissions (e.g., maximum number or maximum duration of the triggered uplink transmissions), and the wireless device 25 may evaluate whether the indicated limit has been reached.

[0075] Alternatively, or in combination thereof, the RAN may also, in some examples, interrupt the triggered recurrent uplink transmissions by sending an uplink transmission interrupting signal to the wireless device 25. The step S44 may therefore comprise evaluating whether an uplink transmission interrupting signal has been received from the RAN. If no uplink transmission interrupting signal has been received (reference S44b in figure 4), then the wireless device 25 may repeat the step S43 of transmitting uplink data to the RAN. In turn, if the wireless device 25 has received an uplink transmission interrupting signal (reference S44a in figure 4), then the wireless device 25 interrupts the recurrent uplink transmissions. For example, the uplink transmission interrupting signal may be received via L1 signaling and / or L2 signaling from the RAN. For example, the uplink transmission interrupting signal may be transmitted by the RAN as a medium access control, MAC, control element, CE, or in downlink control information, DCI.

[0076] As discussed above, figure 5 represents a diagram showing corresponding steps of an exemplary embodiment of a method 50 for exchanging data, which may be implemented by a BS 30 when the wireless device 25 implements the method 40 for exchanging data illustrated by figure 4.

[0077] As illustrated by figure 5, the method 50 for exchanging data comprises a step S50 of transmitting by the BS 30 an uplink transmission triggering signal (received by the wireless device 25 during step S40).

[0078] It should be noted that any suitable format may be used for the uplink transmission triggering signal, and that the choice of a specific format for the uplink transmission triggering signal corresponds to a specific but non-limitative embodiment of the present disclosure. Also, it should be noted that, in some examples, the uplink transmission triggering signal may correspond to the wake-up signal which transitions the wireless device 25 from a sleep mode to an active mode, or it may be transmitted by the RAN after it has transmitted a wake-up signal to the wireless device 25.

[0079] As discussed above, the uplink transmission triggering signal includes an information regarding at least one characteristic of the triggered uplink transmission, which may correspond to e.g., an indication of a traffic class, an indication of uplink transmission occasions, an indication of whether the uplink transmission triggering signal triggers recurrent uplink transmissions, etc.

[0080] In the example of figure 5, it is assumed in a non-limitative manner that the uplinktransmission triggering signal includes at least an indication of whether the uplink transmission triggering signal triggers recurrent (e.g., periodic) uplink transmissions. Non- limitative examples of such an indication have already been provided above.

[0081] If the uplink transmission triggering signal, transmitted by the BS 30, does not trigger recurrent uplink transmissions (reference S50a in figure 5), the method 50 for exchanging data comprises a single step S51 of receiving uplink data from the wireless device 25. In the example of figure 5, a subsequent uplink data transmission by the wireless device 25 needs to be triggered first by the BS 30. In turn, if the uplink transmission triggering signal triggers recurrent uplink transmissions (reference S50b in figure 5), the method 50 for exchanging data comprises a recurrent step S52 of receiving uplink data which is repeated recurrently (e.g., periodically).

[0082] In the non-limitative example of figure 5, it is assumed in a non-limitative manner that the BS 30 may interrupt the recurrent uplink transmissions by transmitting an uplink transmission interrupting signal to the wireless device 25. Accordingly, the method 50 for exchanging data comprises a step S53 of evaluating whether an uplink transmission interrupting signal needs to be transmitted to the wireless device 25.

[0083] As illustrated by figure 5, if the BS 30 determines that the recurrent uplink transmissions need to be interrupted (reference S53a in figure 5), then the method 50 for exchanging data comprises a step S54 of transmitting an uplink transmission interrupting signal to the wireless device 25. It should be noted that any suitable format may be used for the uplink transmission interrupting signal, and that the choice of a specific format for the uplink transmission interrupting signal corresponds to a specific but non-limitative embodiment of the present disclosure. As discussed above, the uplink transmission interrupting signal may for example be transmitted via L1 signaling and / or L2 signaling by the BS 30 (e.g., MAC CE, DCI, etc.).

[0084] In turn, if the BS 30 determines that the recurrent uplink transmissions do not need to be interrupted (reference S53b in figure 5), then the BS 30 repeats the step S52 of receiving uplink data from the wireless device 25.

[0085] In examples where the BS 30 comprises an energy harvesting signal generator 305, the BS 30 may for example start transmitting an energy harvesting (RF) signal to the wireless device 25 before transmitting the uplink transmission triggering signal to said wireless device 25 (not represented in figure 5).

[0086] It is emphasized that the present disclosure is not limited to the above exemplary embodiments. Variants of the above exemplary embodiments are also within the scope of the present disclosure.

Claims

Claims1. 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, wherein the wireless device comprises 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, wherein the method comprises:- (S40) receiving an uplink transmission triggering signal from the RAN, wherein the uplink transmission triggering signal includes an information regarding at least one characteristic of the triggered uplink transmission,- (S42, S43) transmitting uplink data to the RAN, wherein the transmission of uplink data is controlled based on the information regarding at least one characteristic of the triggered uplink transmission.

2. The method (40) according to claim 1 , wherein the information regarding at least one characteristic of the triggered uplink transmission includes an indication of whether the uplink transmission triggering signal triggers recurrent uplink transmissions.

3. The method (40) according to claim 2, wherein the information regarding at least one characteristic of the triggered uplink transmission includes an indication of whether the triggered uplink transmission is a periodic uplink transmission.

4. The method (40) according to claim 3, wherein, if the triggered uplink transmission is a periodic uplink transmission, the information regarding at least one characteristic of the triggered uplink transmission includes an indication of a periodicity of the triggered uplink transmission.

5. The method (40) according to any one of claims 2 to 4, comprising interrupting recurrent uplink transmissions triggered by the uplink transmission triggering signal in response to receiving an uplink transmission interrupting signal from the RAN.

6. The method (40) according to claim 5, wherein the uplink transmission interrupting signal is received via L1 signaling and / or L2 signaling.

7. The method (40) according to claim 6, wherein the uplink transmission interrupting signal is received in a medium access control, MAC, control element, CE, or in downlink control information, DCI.

8. The method (40) according to any one of the preceding claims, wherein the uplink transmission triggering signal is a wake-up signal that transitions the wireless device from a sleep mode to an active mode.

9. A wireless device (25) comprising at least one memory and at least one processor configured to carry out a method (40) according to any one of the preceding claims.

10. A user equipment, UE (20), comprising a wireless device according to claim 9.

11. 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, wherein the BS is configured to exchange data with a wireless device (25) which comprises 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, wherein the method comprises (S50) transmitting to the wireless device (25) an uplink transmission triggering signal, wherein the uplink transmission triggering signal includes an information regarding at least one characteristic of the triggered uplink transmission.

12. The method (50) according to claim 11 , wherein the information regarding at least one characteristic of the triggered uplink transmission includes an indication of whether the uplink transmission triggering signal triggers recurrent uplink transmissions.

13. The method (50) according to claim 12, wherein the information regarding at least one characteristic of the triggered uplink transmission includes an indication of whether the triggered uplink transmission is a periodic uplink transmission.

14. The method (50) according to claim 13, wherein, ifthe triggered uplink transmission is a periodic uplink transmission, the information regarding at least one characteristic of the triggered uplink transmission includes an indication of a periodicity of the triggered uplink transmission.

15. The method (50) according to any one of claims 12 to 14, comprising (S54) transmitting an uplink transmission interrupting signal to the wireless device to interrupt recurrent uplink transmissions.

16. The method (50) according to claim 15, wherein the uplink transmission interrupting signal is transmitted via L1 signaling and / or L2 signaling.

17. The method (50) according to claim 16, wherein the uplink transmission interrupting signal is transmitted in a medium access control, MAC, control element, CE, or in downlink control information, DCI.

18. The method (50) according to any one of claims 11 to 17, wherein the uplink transmission triggering signal is a wake-up signal that transitions the wireless device from a sleep mode to an active mode.

19. A base station, BS (30), comprising at least one memory and at least one processor configured to carry out a method (50) according to any one of claims 11 to 18.

20. A wireless communication system comprising at least one base station (30) according to claim 19 and at least one user equipment (20) according to claim 10.

21. A computer program product (252, 302) comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method (40) according to any one of claims 1 to 8 or a method (50) according to any one of claims 11 to 18.

22. A computer-readable storage medium comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method (40) according to any one of claims 1 to 8 or a method (50) according to any one of claims 11 to 18.

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