Method and apparatus for efficient uplink resource allocation for an ambient IoT device based on a predicted buffer state report

Abstract

The present disclosure relates to methods and apparatus for enabling efficient allocation of uplink resources to a user equipment (UE) (20) having a wireless device (25) including an energy harvesting unit (254) for harvesting ambient energy by providing a predicted buffer status report (PBSR) to a radio access network (RAN).

Description

Technical area

[0001] The present disclosure relates to wireless communication systems, and more particularly, to methods and apparatus for enabling efficient allocation of uplink resources to a very low power wireless device by transmitting a predicted buffer state report to a radio access network (RAN). 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] Currently, a user equipment (UE) desiring dynamic allocation of uplink resources can rely on the buffer status reporting (BSR) policy defined in TS 38.321 V18.0.0. The buffer status reporting (BSR) policy is used to provide the serving base station (gNB) with information about the uplink data volume present at the UE that the UE intends to transmit to the gNB. This enables the gNB to make informed decisions regarding the scheduling of uplink resources to efficiently manage uplink transmissions.

[0006] The BSR procedure requires the UE to initiate a random access channel (RACH) procedure and / or a scheduling request (SR) procedure. This requires the exchange of various signaling messages between the UE and the gNB. Exchanging various signaling messages before the UE is allocated the desired uplink resources impacts electrical power consumption and is not suitable for A-IoT devices. Brief description

[0007] 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 to enable efficient dynamic allocation of uplink resources to a wireless device, such as an A-IoT device, that requires the exchange of fewer signaling messages while simultaneously allocating an amount of uplink resources adapted to the needs of the wireless device.

[0008] To this end, it is proposed that the wireless device transmit a predicted buffer state report, referred to as PBSR, to the radio access network (RAN) before the wireless device has uplink data to transmit. This PBSR is determined by the wireless device, for example, based on the wireless device's uplink transmission context and represents a volume of uplink data that the wireless device expects to transmit in the future. For a very low-power wireless device, such as an A-IoT device, the RAN typically repeatedly triggers uplink transmissions by the wireless device.When it triggers an uplink transmission, the RAN can then directly allocate uplink resources to the wireless device, with a set of allocated uplink resources determined based on the PBSR previously received from that wireless device, without the need for further signaling messages to be exchanged between the RAN and that wireless device.

[0009] According to a first aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, wherein the method is 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, wherein the wireless device further comprises a communication unit configured to exchange data with a radio access network (RAN) of the wireless communication system, the method comprising: - Transmitting, to the RAN, a predicted buffer status report (PBSR) containing an indication of a volume of uplink data that the wireless device may need to transmit to the RAN, wherein the PBSR is transmitted before the wireless device has the uplink data to be transmitted to the RAN, - receiving an uplink transmission trigger signal from the RAN, wherein the uplink transmission trigger signal includes an allocation of uplink resources to the wireless device.

[0010] 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.

[0011] In some embodiments, the method according to the first aspect comprises transmitting uplink data using the uplink resources allocated to the wireless device.

[0012] In some embodiments, the method according to the first aspect comprises determining the PBSR based on at least one characteristic of uplink data to be transmitted by the wireless device.

[0013] In some embodiments of the method according to the first aspect, the indication of the volume of uplink data that the wireless device may need to transmit corresponds to a maximum volume of uplink data that the wireless device may need to transmit in response to receiving a trigger signal for an uplink transmission.

[0014] In some embodiments of the method according to the first aspect, the PBSR is transmitted in a user equipment (UE) capability message.

[0015] In some embodiments of the method according to the first aspect, the trigger signal for an uplink transmission is received without the wireless device transmitting a prior request for an uplink resource allocation to the RAN.

[0016] In some embodiments of the method according to the first aspect, the trigger signal for an uplink transmission is a wake-up signal from the RAN that transitions the wireless device from a sleep mode to an active mode, or a signaling message received after receiving a wake-up signal from the RAN.

[0017] 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.

[0018] 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.

[0019] According to a fourth aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, wherein the method is 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 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: - receiving, from the wireless device, a predicted buffer status report (PBSR) containing an indication of a volume of uplink data that the wireless device may need to transmit, wherein the PBSR is received before the wireless device has the uplink data to be transmitted to the RAN, - transmitting a trigger signal for an uplink transmission to the wireless device, wherein the trigger signal for an uplink transmission includes an allocation of uplink resources to the wireless device determined based on the PBSR.

[0020] 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.

[0021] In some embodiments, the method according to the fourth aspect comprises receiving uplink data in the uplink resources allocated to the wireless device.

[0022] In some embodiments, the method according to the fourth aspect comprises evaluating a trigger criterion for an uplink transmission and, in response to the trigger criterion for an uplink transmission being verified: allocating uplink resources to the wireless device based on the PBSR and transmitting the trigger signal for an uplink transmission to the wireless device.

[0023] In some embodiments of the method according to the fourth aspect, the trigger criterion for an uplink transmission is verified without requiring the wireless device to receive a prior request for uplink resource allocation.

[0024] In some embodiments of the method according to the fourth aspect, the indication of the volume of uplink data that the wireless device may need to transmit corresponds to a maximum volume of uplink data that the wireless device may need to transmit in response to receiving a trigger signal for an uplink transmission.

[0025] In some embodiments of the method according to the fourth aspect, the PBSR is received in a user equipment (UE) capability message.

[0026] In some embodiments of the method according to the fourth aspect, the trigger signal for an uplink transmission is a wake-up signal that transitions the wireless device from a sleep mode to an active mode, or a signaling message that is transmitted after transmitting a wake-up signal to the wireless device.

[0027] In some embodiments of the method according to the fourth aspect, the trigger signal for an uplink transmission is a signaling message specifically addressed to the wireless device.

[0028] In some embodiments, the method according to the fourth aspect comprises beginning to transmit an energy harvesting signal to the wireless device before transmitting the trigger signal for an uplink transmission 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 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 on 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 present disclosure aims to enable efficient dynamic allocation of uplink resources to a wireless device 25 that requires the exchange of fewer signaling messages while allocating an amount of uplink resources adapted to the needs of the wireless device 25.

[0055] To this end, it is proposed that the wireless device 25 transmit a predicted buffer state report, hereinafter referred to as PBSR, to the radio access network (RAN) before the wireless device 25 has uplink data to transmit. This PBSR represents a volume of uplink data that the wireless device 25 expects to transmit to the RAN in the future. When it triggers an uplink transmission, the RAN can then directly allocate uplink resources to the wireless device 25, with the amount of uplink resources being determined by the RAN based on the PBSR previously received from this wireless device 25, without necessarily requiring further signaling messages to be exchanged between the RAN and the wireless device 25.

[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 transmitting, to the RAN, a predicted buffer status report (PBSR), which corresponds to an indication of a volume of uplink data that the wireless device 25 expects to transmit to the RAN in the future. By "predicted," the authors mean that the PBSR corresponds to an a priori estimate of the volume of uplink data that the wireless device 25 must transmit during the next uplink transmission triggered by the RAN, before the estimated volume of uplink data has actually arrived at the uplink buffer(s) of the wireless device.

[0058] For example, the PBSR is determined by the wireless device 25 based on at least one characteristic of uplink data to be transmitted by the wireless device 25.

[0059] For example, the at least one characteristic of the uplink data to be transmitted may include a traffic class (priority level, latency requirement, etc.) and / or a category of a UE 20 and / or a type of service running on the UE 20, etc. For example, based on the type of service running on the UE, the wireless device 25 may predict the volume of uplink data it may need to transmit during each RAN-triggered uplink transmission.

[0060] Alternatively, or in combination, the wireless device 25 may use a history of past uplink transmissions to predict the volume of uplink data it may need to transmit during the next uplink transmission. Alternatively, or in combination, when the UE 20 periodically generates uplink data of a predetermined size to be transmitted, the wireless device 25 may predict the volume of uplink data it may need to transmit during the next uplink transmission based on the approximate time gap between RAN-triggered uplink transmissions (where the approximate time gap may be estimated, pre-agreed with the RAN, or determined as the average or maximum time gap observed between past RAN-triggered uplink transmissions).

[0061] Any estimation method may be used to predict the volume of uplink data that may be transmitted in the next triggered uplink transmission, and the choice of a specific method corresponds to a specific, but non-limiting, embodiment of the present disclosure.

[0062] In preferred embodiments, the PBSR may be conservative, ie, it may correspond to a maximum volume of uplink data that wireless device 25 may need to transmit during the next RAN-triggered uplink transmission. However, in other examples, the PBSR may also correspond, for example, to an average or minimum volume of uplink data that wireless device 25 may need to transmit during each RAN-triggered uplink transmission.

[0063] It is noted that the transmitted PBSR may correspond to a static configuration or a dynamic configuration.

[0064] By "static configuration," the authors mean that the PBSR remains valid for all subsequent RAN-triggered uplink transmissions unless overwritten by a new static configuration transmitted by the same wireless device 25. With a static configuration, the PBSR does not need to be transmitted before any future RAN-triggered uplink transmission and may even be transmitted to the RAN only once (or at least once per serving BS 30).

[0065] By “dynamic configuration,” the authors mean that the PBSR remains valid only for a specified number of subsequent uplink transmissions and, in some cases, may only remain valid for a single subsequent uplink transmission.

[0066] The PBSR may be transmitted in any type of signaling message, and the choice of a specific type of signaling message corresponds to a specific, but non-limiting, embodiment of the present disclosure.

[0067] For example, the signaling message containing the PBSR may be transmitted by the RAN shortly after the wireless device 25 has been authenticated. For example, the PBSR may be a UE capability message (RRC message) sent by the wireless device 25. Including the PBSR in a UE capability message may be used, for example, for static configuration of the PBSR.

[0068] According to another example, the wireless device 25 may transmit a PBSR during an ongoing uplink transmission or at the end of an ongoing uplink transmission, e.g., before the wireless device 25 enters a sleep mode. Such a PBSR transmitted during or at the end of an ongoing uplink transmission is to be used for the next uplink transmission initiated by the RAN. Such a PBSR transmission scheme can be used, for example, for a dynamic configuration of the PBSR, but also for its static configuration if the transmitted PBSR is to remain valid for all subsequent uplink transmissions (unless overwritten by a new static configuration).

[0069] It is noted that both approaches, a static and a dynamic configuration of the PBSR, may also be combined in some embodiments. For example, the wireless device 25 may transmit a static configuration of the PBSR to be used by default, e.g., in a UE capability message. Subsequently, the wireless device 25 may transmit a dynamic configuration of the PBSR, e.g., during or at the end of an ongoing uplink transmission, which temporarily replaces the static configuration (e.g., only for a predetermined number of triggered uplink transmissions).

[0070] Any suitable format may be used for the PBSR, and the choice of a specific format is a specific, but non-limiting, embodiment of the present disclosure. The format may, in some cases, depend on whether it corresponds to a static configuration or a dynamic configuration. For example, the PBSR format may be based on the BSR media access control (MAC) control element (CE) format.

[0071] As through Fig. As illustrated in Figure 4, the method 40 for exchanging data includes a step S41 of receiving an uplink transmission trigger signal from the RAN. The purpose of the uplink transmission trigger signal is to indicate to the wireless device 25 that it may initiate an uplink transmission on the uplink resources assigned to the wireless device 25.

[0072] 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.

[0073] In the present case, the uplink transmission trigger signal includes an indication of uplink resources dynamically allocated to the wireless device 25, wherein the volume of allocated uplink resources is determined by the RAN based on the PBSR previously transmitted by the wireless device 25.

[0074] It is noted that the uplink transmission may be initiated unilaterally by the RAN without requiring the wireless device 25 to transmit a prior request for dynamic allocation of uplink resources to the RAN, e.g., without requiring the wireless device 25 to send a scheduling request (SR) or without performing a random access channel (RACH) access. As discussed above, in some cases, the wireless device 25 is in a sleep mode and only transitions to an active mode upon receiving the uplink transmission trigger signal (or a wake-up signal transmitted shortly before the uplink transmission trigger signal).

[0075] In the Fig. 4, the method 40 for exchanging data includes a step S42 of transmitting uplink data using all or a portion of the uplink resources allocated to the wireless device 25.

[0076] It is noted that the amount of uplink resources allocated by the RAN may not match the volume of uplink data that the wireless device 25 actually needs to transmit during the triggered uplink transmission because the uplink resources are allocated for the RAN-triggered uplink transmission without being explicitly requested by the wireless device 25 beforehand.

[0077] For example, it may happen that wireless device 25 has no uplink data to transmit. In such a case, wireless device 25 may skip step S42 (which is not executed), or it may use only a portion of the allocated uplink resources to notify the RAN that it has no uplink data in its uplink buffer(s), or it may use all allocated uplink resources, for example, by padding the uplink data with dummy data.

[0078] According to another example, wireless device 25 may have a volume of uplink data to be transmitted that is smaller than the amount of uplink resources allocated by the RAN. This could be the most common situation when the PBSR corresponds to a predicted maximum volume of uplink data. In such a case, wireless device 25 may use only a portion of the allocated uplink resources, or it may use all of the allocated uplink resources, for example, by padding the uplink data with dummy data.

[0079] According to yet another example, wireless device 25 may have a volume of uplink data that is greater than the amount of uplink resources allocated by the RAN. In such a case, wireless device 25 may, for example, discard the excess uplink data (if possible), retain the excess data for the next RAN-triggered uplink transmission (if possible), request additional uplink resources in a conventional manner (e.g., by sending a BSR) during the ongoing uplink transmission, etc.

[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 receiving a PBSR from the wireless device 25. As discussed above, the PBSR may be received, for example, with a UE capability message from the wireless device 25, in a signaling message transmitted by the wireless device 25 before it enters a sleep mode, etc.

[0082] As through Fig. 5, 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 BS 30.

[0083] 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. For example, the uplink transmission trigger signal may correspond to a signaling message specifically addressed to wireless device 25. For example, the uplink transmission trigger signal may include an identifier of wireless device 25 to enable wireless device 25 to detect that it is the recipient of this information.

[0084] Also, in some cases, the uplink transmission trigger signal may correspond to a wake-up signal that transitions the wireless device 25 from a sleep mode to an active mode, or it is a signaling message transmitted after transmitting a wake-up signal to the wireless device 25 (to transition the wireless device 25 to an active mode before transmitting the uplink transmission trigger signal).

[0085] As discussed above, the uplink transmission trigger signal includes a dynamic allocation of uplink resources to the wireless device 25, and the amount of uplink resources allocated to the wireless device 25 is determined by the BS 30 based on the PBSR previously received from that wireless device 25.

[0086] For example, the BS 30 may allocate an amount of uplink resources that is identical to the predicted volume of uplink data indicated in the PBSR. In other examples, the BS 30 may allocate an amount of uplink resources that is different from the predicted volume of uplink data indicated in the PBSR, e.g., less than the predicted volume. For example, if the utilization level of the BS 30 is important, then the BS 30 may allocate fewer uplink resources than those strictly required to transmit the predicted volume of uplink data indicated by the PBSR. This may also be the case if the PBSR corresponds to a predicted maximum volume of uplink data that the wireless device 25 may need to transmit, since the wireless device 25 may have a smaller volume of uplink data than the predicted maximum volume to transmit.For example, if the utilization level of the BS 30 is low, then the BS 30 may also decide to allocate more uplink resources than those strictly required to transmit the predicted volume of uplink data indicated by the PBSR, in particular if the PBSR corresponds to a predicted average or minimum volume of uplink data to be transmitted.

[0087] In the Fig. 5, the method 50 for exchanging data includes a step S52 of receiving uplink data from the wireless device 25 in all or part of the uplink resources allocated to the wireless device 25. As discussed above, there may be times when the wireless device 25 does not have any uplink data to transmit because the uplink resources are allocated without first being explicitly requested by the wireless device 25. In such a case, the wireless device 25 may skip step S42 (which is not executed), and the BS 30 may not receive any uplink data at step S52 (which then consists of searching for uplink data in the allocated uplink resources and determining that no uplink data has been transmitted by the wireless device 25).

[0088] As discussed above, the BS 30 initiates the uplink transmission without having to receive a prior request for uplink resource allocation from the wireless device 25. This is because, in some cases, a wireless device 25 may be in idle mode when the BS 30 decides to initiate an uplink transmission from that wireless device 25.

[0089] In some examples and as Fig. 5, the method 50 for exchanging data comprises a step S53 of evaluating a trigger criterion for an uplink transmission for the wireless device 25. If the trigger criterion for an uplink transmission is met (reference symbol S53a in Fig. 5), the BS 30 allocates uplink resources to the wireless device based on the PBSR received from the wireless device 25 and transmits the uplink transmission trigger signal to the wireless device 25 with an indication of the allocated uplink resources. However, if the uplink transmission trigger criterion is not met (reference symbol S53b in Fig. 5), the trigger signal for an uplink transmission is not transmitted. For example, and as Fig. 5, the step S53 of evaluating the trigger criterion for an uplink transmission is repeatedly executed by the BS 30 until it detects that the trigger criterion for an uplink transmission is verified.

[0090] Various types of trigger criteria for an uplink transmission may be considered, and the selection of a specific trigger criterion for an uplink transmission corresponds to a specific, but non-limiting, embodiment of the present disclosure.

[0091] For example, the trigger criterion for an uplink transmission is verified when the BS 30 assumes that the wireless device 25 has uplink data to transmit. For example, the BS 30 may decide to repeatedly, e.g., periodically transmit a trigger signal for an uplink transmission based on a predetermined time gap or periodicity between BS-triggered uplink transmissions. Such a time gap or periodicity may, for example, be previously agreed upon with the wireless device 25 or with a user / owner of the UE 20, or it may be predetermined based on the uplink transmission context of the wireless device (traffic class, UE category, service type, etc.).Alternatively, or in combination therewith, the trigger criterion for an uplink transmission is verified when the BS 30 receives a trigger command via the CN, for example from an owner of the UE 20 who wishes to receive uplink data from the UE 20.

[0092] For example, in examples where the BS 30 includes an energy harvesting signal generator 305, the BS 30 may begin transmitting an energy harvesting (RF) signal to the wireless device 25 before transmitting the trigger signal for an uplink transmission to the wireless device 25. In some cases, the energy harvesting (RF) signal may be used as a wake-up signal that transitions the wireless device 25 to an active mode.

[0093] 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.

[0094] For example, the present disclosure has been made primarily with respect to a wireless device 25 including an energy harvesting unit 254 configured to convert ambient energy into electrical energy stored in an energy storage unit 255. However, in some cases, the present disclosure may also be applied to wireless devices 25 that do not include such an energy harvesting unit and that operate only with an energy storage unit 255 (which may or may not be rechargeable).

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) transmitting, to the RAN, a predicted buffer status report (PBSR) containing an indication of a volume of uplink data that the wireless device may need to transmit to the RAN, wherein the PBSR is transmitted before the wireless device has the uplink data to be transmitted to the RAN, - (S41) receiving an uplink transmission trigger signal from the RAN, wherein the uplink transmission trigger signal includes an allocation of uplink resources to the wireless device. [2] The method (40) of claim 1, comprising determining the PBSR based on at least one characteristic of uplink data to be transmitted by the wireless device. [3] The method (40) of any preceding claim, wherein the indication of the volume of uplink data that the wireless device may need to transmit corresponds to a maximum volume of uplink data that the wireless device may need to transmit in response to receiving an uplink transmission trigger signal. [4] A method (40) according to any one of the preceding claims, wherein the PBSR is transmitted in a user equipment (UE) capability message. [5] The method (40) of any preceding claim, wherein the trigger signal for an uplink transmission is received without the wireless device transmitting a prior request for uplink resource allocation to the RAN. [6] The method (40) of any preceding claim, wherein the trigger signal for an uplink transmission is a wake-up signal from the RAN transitioning the wireless device from a sleep mode to an active mode, or is a signaling message received after receiving a wake-up signal from the RAN. [7] 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. [8] A user equipment (UE) (20) comprising a wireless device according to claim 7. [9] A method (50) for exchanging data in a wireless communication system, the method being implemented by a base station (BS) (30) of a radio access network (RAN) of the wireless communication system, the BS being configured to exchange data with a wireless device (25) comprising an energy harvesting unit (254) configured to convert ambient energy into electrical energy that is stored in an energy storage unit (255) of the wireless device, the method comprising: - (S50) receiving, from the wireless device, a predicted buffer status report (PBSR) containing an indication of a volume of uplink data that the wireless device may need to transmit, wherein the PBSR is received before the wireless device has the uplink data to be transmitted to the RAN, - (S51) transmitting a trigger signal for an uplink transmission to the wireless device, wherein the trigger signal for an uplink transmission includes an allocation of uplink resources to the wireless device determined based on the PBSR. [10] The method (50) of claim 9, comprising evaluating (S53) a trigger criterion for an uplink transmission and, in response to the trigger criterion for an uplink transmission being verified: allocating uplink resources to the wireless device based on the PBSR and transmitting (S51) the trigger signal for an uplink transmission to the wireless device. [11] The method (50) of claim 10, wherein the trigger criterion for an uplink transmission is verified without requiring the wireless device to receive a prior request for uplink resource allocation. [12] The method (50) of any one of claims 9 to 11, wherein the indication of the volume of uplink data that the wireless device may need to transmit corresponds to a maximum volume of uplink data that the wireless device may need to transmit in response to receiving an uplink transmission trigger signal. [13] The method (50) of any one of claims 9 to 12, wherein the PBSR is received in a user equipment (UE) capability message. [14] The method (50) of any one of claims 9 to 13, wherein the trigger signal for an uplink transmission is a wake-up signal that transitions the wireless device from a sleep mode to an active mode, or is a signaling message transmitted after transmitting a wake-up signal to the wireless device. [15] The method (50) of any one of claims 9 to 14, comprising beginning to transmit an energy harvesting signal to the wireless device (25) prior to transmitting the trigger signal for an uplink transmission to that wireless device. [16] Base station (BS - base station) (30), comprising at least one memory and at least one processor configured to carry out a method (50) according to any one of claims 9 to 15. [17] A wireless communication system comprising at least one base station (30) according to claim 16 and at least one user device (20) according to claim 8. [18] 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 6 or a method (50) according to any one of claims 9 to 15. [19] 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 6 or a method (50) according to any one of claims 9 to 15.

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