Method and device for controlling the signaling effort by a RAN when multiple RA methods are initiated simultaneously by Ambient IoT devices

Abstract

The present disclosure relates to methods and devices for controlling the signaling effort by a radio access network (RAN) when several random access (RA) methods are initiated simultaneously by several wireless devices (25), such as ambient IoT devices.

Description

Technical field

[0001] The present disclosure relates to wireless communication systems and in particular methods and devices for controlling the signaling effort by a radio access network (RAN) when several random access (RA) methods are initiated simultaneously by several wireless devices, such as ambient IoT devices. background

[0002] The Internet of Things (IoT) enables various devices to connect to the internet to send data and / or receive instructions. Tens of billions of IoT devices are already in use, and the global number is expected to increase rapidly. This necessitates massive connectivity. 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 unlock new markets within 3GPP systems. These technologies could offer a significantly higher number of connections and / or device density than current 3GPP IoT technologies, while providing significantly lower complexity and power consumption. Examples include narrowband IoT (NB-IoT) and long-term evolution machine-type communications (LTE-MTC). Specifically, 3GPP is currently defining ambient IoT (A-IoT) technologies (see, for example, technical report TR 38.848 V18.0).0), which aim to enable IoT devices with very low power consumption, which could be either battery-free devices without energy storage capability (performing transmission by backscattering) or devices with an energy storage device that does not need to be manually replaced or recharged (performing wireless energy harvesting from the environment (EH) from one or more energy sources).

[0004] By "very low power consumption" or "A-IoT" devices, the authors mean devices that have 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: - approximately 1 µW peak power consumption with energy storage, neither with 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, the 3GPP specifications for 5G-NR define various types of random-access (RAN) procedures to enable a user equipment (UE) to access RA uplink resources (RACH - random-access channel). These RA procedures can be used to provide the UE with a communication identifier, which is used when exchanging data with the RAN. In 5G-NR, for example, the communication identifier corresponds to the cell-radio network temporary identifier (C-RNTI), which is used as an identifier for the UE's radio resource control (RRC) connection and for scheduling communication resources for the UE.

[0006] The current 5G-NR specifications define contested and non-contested RA procedures. A contested RA procedure is a true RA procedure through which the UE randomly selects RACH uplink resources, such as an RA preamble. For example, the current 5G-NR specifications define a 4-step contested RA procedure based on the exchange of four messages: Msg1 (from the UE to the RAN, using the selected RA preamble), Msg2 (from the RAN to the UE, containing a temporary C-RNTI (TC-RNTI - temporary C-RNTI) and an uplink grant), Msg3 (from the UE to the RAN, transmitted in the uplink resources specified by the uplink grant), and Msg4 (from the RAN to the UE, containing the C-RNTI specified by the RAN for the UE). The non-competitive RA procedure avoids the need for a competitive solution by assigning dedicated RA preambles to some of the UEs.

[0007] Existing concurrent RA methods can be difficult to apply to A-IoT devices, and the use of specific concurrent RA methods for A-IoT devices is being considered. A three-step RA method is being considered, which includes an initial message from the A-IoT device to the RAN containing a direct access identifier generated by the A-IoT device. The direct access identifier is then reflected by the RAN in a second message, which may also contain a communication identifier (e.g., for planning purposes and / or for subsequent non-concurrent RA methods). The A-IoT device can then transmit uplink data (e.g., a unique device identifier and / or higher-layer data) in a third message.An optional fourth message can also be transmitted from the RAN to the A-IoT device, for example to handle a transmission error of the third message.

[0008] In some scenarios, A-IoT devices can initiate a competitive RA procedure when triggered by the RAN, which can lead to many RA procedures being initiated simultaneously by the triggered A-IoT devices.

[0009] However, the risk of collisions increases with the number of deployed A-IoT devices. The RAN could also become overloaded if many A-IoT devices simultaneously initiate RA procedures. Furthermore, in the event of numerous collisions due to many A-IoT devices attempting to access RA uplink resources, the RAN would have to trigger retransmissions from the colliding devices, increasing the signaling overhead for the RAN and the power consumption of the A-IoT devices.

[0010] Therefore, there is a need for improved RA procedures for A-IoT devices. Brief description

[0011] 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. Specifically, the present disclosure aims to propose a solution that enables better control of the signaling overhead by a RAN when multiple RA procedures are initiated simultaneously by wireless devices, such as A-IoT devices.

[0012] To this end, it is proposed to enable the RAN to halt (or not halt) an RA procedure initiated by a wireless device by sending to that wireless device an indication of whether the RA procedure should continue. Such an indication, referred to below as Direct Access Authorization Information, can be used, for example, to halt an RA procedure initiated by a wireless device when the RAN is under high load, when the Direct Access identifier selected by the wireless device conflicts with (i.e., is the same as) a Direct Access identifier selected by another wireless device, and so on.Thus, by transmitting the information to authorize direct access, the RAN can control the number of parallel RA procedures and / or the number of collisions to be resolved, thereby reducing the signaling overhead for the RAN and the power consumption for the wireless devices.

[0013] 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, the wireless device comprising a communication unit configured to exchange data with a radio access network (RAN) of the wireless communication system, wherein the method comprises the following: - Selecting a direct access identifier, - Initiating a direct access procedure by transmitting an initial message to the RAN, the initial message containing the selected direct access identifier, - Receiving a second message from the RAN, the second message containing the selected direct access identifier and the information for authorizing direct access, - in response to the information indicating that the direct access authorization process is not authorized: halting the direct access process, - in response to the information indicating that the direct access authorization procedure is authorized: Continue the direct access procedure.

[0014] In some embodiments, the method according to the first aspect may further comprise one or more of the following optional features, which may be considered either alone or in a technically possible combination.

[0015] In some embodiments of the method according to the first aspect, continuing the direct access method includes transmitting a third message to the RAN in response to the second message, wherein the third message contains uplink data.

[0016] In some embodiments, the procedure according to the first aspect, in response to the information for authorizing direct access indicating that the direct access procedure is not authorized, includes: selecting a different direct access identifier and initiating a different direct access procedure.

[0017] In some embodiments of the method according to the first aspect, the information for authorizing direct access corresponds to a single bit.

[0018] In some embodiments of the method according to the first aspect, a value of 0 in the Direct Access Approval Information indicates that the Direct Access method is approved, and a value of 1 in the Direct Access Approval Information indicates that the Direct Access method is not approved.

[0019] In some embodiments of the method according to the first aspect, wherein the wireless device is configured to exchange data with the RAN using a communication identifier specified by the RAN, the method, in response to the information for authorizing direct access indicating that the direct access procedure is authorized, includes using the selected direct access identifier as the communication identifier.

[0020] In some embodiments of the method according to the first aspect, the direct access method is initiated in response to receiving a trigger signal for an uplink transmission from the RAN.

[0021] In some embodiments of the method according to the first aspect, the trigger signal for an uplink transmission is a paging message.

[0022] 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 one of the embodiments of the first aspect.

[0023] According to a third aspect, the present disclosure relates to a user equipment (UE) comprising a wireless device according to one of the embodiments of the present disclosure.

[0024] 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 network node (NN) of a radio access network (RAN) of the wireless communication system, and wherein the method comprises the following: - Receiving, from a wireless device, a first message of a direct access method, wherein the first message contains a direct access identifier, - Transmitting a second message to the wireless device in response to the first message, the second message containing the received direct access identifier and information for authorizing direct access, indicating whether the direct access procedure should be continued by the wireless device.

[0025] In some embodiments, the method according to the fourth aspect may further include one or more of the following optional features, which may be considered either alone or in a technically possible combination.

[0026] In some embodiments, the method according to the fourth aspect, where the transmitted information for authorizing direct access indicates that the direct access method is to be continued, includes receiving a third message from the wireless device, wherein the third message contains uplink data.

[0027] In some embodiments, the method according to the fourth aspect includes determining the information for authorizing direct access by evaluating a criterion for authorizing direct access.

[0028] In some embodiments of the method according to the fourth aspect, the criterion for authorizing direct access is evaluated by using a utilization level of the NN.

[0029] In some embodiments of the method according to the fourth aspect, the criterion for authorizing direct access is evaluated by comparing the direct access identifier received by the wireless device with direct access identifiers received by other wireless devices.

[0030] In some embodiments of the method according to the fourth aspect, the information for authorizing direct access corresponds to a single bit.

[0031] In some embodiments of the method according to the fourth aspect, a value of 0 in the Direct Access Approval Information indicates that the Direct Access method is approved, and a value of 1 in the Direct Access Approval Information indicates that the Direct Access method is not approved.

[0032] In some embodiments of the method according to the fourth aspect, wherein the wireless device is configured to exchange data with the RAN using a communication identifier specified by the RAN, information for authorizing a direct access, indicating that the direct access method is authorized, further indicates that the received direct access identifier is to be used by the wireless device as a communication identifier.

[0033] According to a fifth aspect, the present disclosure relates to a network node (NN) 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. In some embodiments, the NN is a base station or an intermediate device between a base station and wireless devices.

[0034] According to a sixth aspect, the present disclosure relates to a wireless communication system comprising at least one network node (e.g. a base station or an intermediate device) 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.

[0035] According to a seventh aspect, the present disclosure relates to a computer program product comprising instructions which, when executed by at least one processor, configure the at least one processor to perform a method for exchanging data according to one of the embodiments of the present disclosure. The computer program product may use any programming language and may be in the form of source code, object code, or any form between source code and object code, such as in a partially compiled form, or in any other desired form.

[0036] According to an eighth aspect, the present disclosure relates to a (non-volatile) computer-readable storage medium comprising instructions which, when executed by at least one processor, configure the at least one processor to perform a method for exchanging data according to one of the embodiments of the present disclosure. Brief description of the drawings

[0037] The invention will be better understood by reading the following description, which is given as an example that is in no way limiting, and which refers to the figures that show the following: - 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 data exchange procedures implemented by a wireless device of a UE or BS, - Fig. 6: A flowchart illustrating examples of a sequence of messages exchanged between a wireless device and a network node (BS),

[0038] In these figures, reference symbols that are identical from one figure to the next denote identical or analogous elements. For clarity, the elements shown are not to scale unless explicitly stated otherwise. Detailed description

[0039] The detailed description below, with reference to the figures, is intended to describe various configurations and not to represent the only configurations in which the concepts described herein can be practically implemented. The detailed description includes specific details for the purpose of a comprehensive understanding of the various concepts. However, it is clear to those skilled in the art that these concepts can be practically implemented without these specific details. For example, even if terminology from 3GPP, e.g., from 5G NR, is used in this disclosure to explain embodiments, this should not be seen as limiting the scope of protection of this disclosure.

[0040] In general, all terms used herein shall be interpreted according to their usual meaning in the relevant technical field, unless a different meaning is explicitly stated and / or can be inferred from the context in which they are used. All references to an element, device, component, means, step, etc., shall be interpreted as referring to at least one occurrence of the element, device, component, means, step, etc., unless expressly stated otherwise.Likewise, the sequence of steps of any processes disclosed herein, particularly in the figures, is provided for illustrative purposes only and is not intended to limit the present disclosure, which can be applied with the same steps performed in a different order and / or with all or some of the steps performed in parallel or together, unless a step is expressly described as following or preceding another step and / or it is implicit that a step must follow or precede another step. Furthermore, steps shown in a figure that are surrounded by a dashed line are to be considered optional for the embodiment shown in that figure. Any feature of one of the embodiments disclosed herein may, if appropriate, be applied to any other embodiment.Likewise, any advantage of one embodiment may apply to any other embodiment, and vice versa. Further objectives, features, and advantages of the embodiments included will become apparent from the following description.

[0041] Fig. Figure 1 schematically represents an example of a wireless communication system, which could be, for example, a 5G NR wireless communication system. In particular, it represents Fig. Figure 1 represents 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.

[0042] In the through Fig. In the illustrated example 1, the RAN includes one base station (BS) 30. Naturally, the RAN can include more than one BS 30 to extend the coverage area of ​​the wireless communication system. Each of these BSs can 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 implemented wireless communication standards.

[0043] In the through Fig. In the illustrated example 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 directly exchanges data (user data and control data) with a BS 30 of the RAN (referred to as topology 1 in TR 38.848 V18.0.0). Part b) of Fig. Figure 1 schematically illustrates an example in which the UE 20 indirectly exchanges data (payload and control data) with a BS 30 of the RAN via one or more intermediate devices 31 (referred to as Topology 2 in TR 38.848 V18.0.0). Each intermediate device 31 can be, for example, a relay, an IAB (integrated access and backhaul) node, another UE 20 / wireless device 25, a repeater, a reconfigurable intelligent surface (RIS), etc. TR 38.848 V18.0.0 also defines other topologies, in particular Topology 3, which also uses an intermediate device (referred to as an "assisting node" in TR 38.848 V18.0.0), but only in the uplink or downlink.

[0044] In the following, the authors define a network node (NN) as any device through which a UE 20 can communicate with the RAN. Depending on the topology under consideration, an NN could, for example, correspond to a BS 30 or an intermediate device 31.

[0045] Fig. Figure 2 schematically represents an example of a wireless device 25 suitable for implementing any method discussed in the present disclosure and carried out on a UE 20 or an intermediate device 31. Essentially, the wireless device 25 corresponds to a device that provides wireless connectivity to the RAN of the wireless communication system and can be used to exchange data with the RAN. For example, the wireless device 25 is 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.

[0046] Such a wireless device 25 can be implemented in a UE 20, as described by Fig. 2 illustrated, may be included. The UE 20 may, for example, be 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, a radio-frequency identification (RFID) tag, or the like, etc., or any other device capable of performing applications that require data to be exchanged with remote receivers via the wireless device 25.

[0047] As through Fig. As illustrated in 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, for example, include 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 disk, solid-state storage, optical media, electronic storage, etc.).The one or more memory locations 251 can store a computer program product 252 in the form of a set of program-coded 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, which is carried out on the side of a UE according to one of the embodiments disclosed herein.

[0048] As through Fig. As illustrated in Figure 2, the wireless device 25 also includes a (wireless) communication unit 253, which is designed for (direct or indirect) data exchange with BSs 30 of the RAN using radio signals and, in some cases (e.g., the intermediate device 31), with other wireless devices 25. The communication unit 253 can implement one or more wireless communication protocols and can, 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, for example, with A-IoT capabilities.

[0049] As discussed above, in some examples the communication unit 253 may not include either DL (downlink) or UL (uplink) amplification capability (the UL transmission is backscattered on an externally provided carrier wave). In other examples, the 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).

[0050] In the through Fig. In the non-restrictive example 2, the wireless device 25 also includes an energy harvesting unit 254 and an energy storage unit 255 of the wireless device.

[0051] The energy storage unit 255 can be any type of electrical energy accumulator and can, for example, include one or more capacitors, one or more batteries, etc. The energy storage unit 255 is used to supply electrical energy to the other components of the wireless device 25 that require electrical energy, such as the one or more processors 250, the one or more memory units 251, and, in some cases, the (wireless) communication unit 253.

[0052] 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 located outside the wireless device 25, which is received by the wireless device 25 without any wires between the energy sources and the wireless device 25. Thus, the energy harvesting unit 254 is designed such that the wireless device 25 can operate autonomously without the need for manual replacement or recharging of the energy storage unit 255. The energy harvesting unit 254 can, for example, collect energy from various energy sources, including sunlight, heat, motion or vibrations, radio frequency (RF), etc.

[0053] 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 can be, for example, 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 can originate from external 3G, 4G, 5G, NR, WiFi, WiMAX, Bluetooth, DAB, etc., devices located near the wireless device 25.Alternatively, or in combination with this, the RF signals can originate from within the wireless communication system, for example, from BSs 30 of the RAN that can transmit an energy-harvesting (RF) signal to wireless (A-IoT) devices 25 within their coverage area, and / or from devices that are separate from the BSs 30 but are used to enable energy harvesting at the wireless (A-IoT) devices 25 of the wireless communication system. In some examples, if RF signals are used to feed electrical energy into the energy storage unit 255, the energy harvesting unit 254 can be contained within the (wireless) communication unit 253.

[0054] In some examples, the electrical energy harvested by the energy harvesting unit 254 can be directly supplied to the other facilities of the wireless device 25, with the energy storage unit 255 being optional in this case and not required to be included in the wireless device.

[0055] Fig. Figure 3 schematically represents an example of a BS 30 suitable for implementing a process discussed in the present disclosure and carried out by the RAN.

[0056] As through Fig. As illustrated in Figure 3, the BS 30 comprises one or more processors 300 and one or more memories 301. The one or more processors 300 may, for example, include 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 disk, solid-state storage, optical media, electronic storage, etc.).The one or more memory locations 301 can store a computer program product 302 in the form of a set of program-coded 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, which is carried out on the RAN side according to one of the embodiments disclosed herein.

[0057] As through Fig. As illustrated in Figure 3, 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 contained in these UEs 20. The wireless communication unit 303 can, for example, be a 3G, 4G, 5G, NR, WiFi, WiMax, etc. transceiver or the like. In preferred embodiments, the wireless communication unit 303 of BS 30 includes a 5G NR transceiver, for example, with A-IoT capabilities. In some examples, the wireless communication unit 303 can also transmit carrier waves to the wireless devices 25, which perform uplink transmissions with backscattering.

[0058] As through Fig. As illustrated in Figure 3, the BS 30 may in some examples also include a Network Communication Unit 304, which is 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.

[0059] As through Fig. As illustrated in Figure 3, the BS 30 may in some examples also include an energy-harvesting signal generator 305 that generates energy-harvesting (RF) signals enabling wireless devices 25 within its coverage area to feed electrical energy into their energy storage units 255 via their energy-harvesting units 254. The energy-harvesting (RF) signals can 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 mentioned above, such energy-harvesting (RF) signals may optionally be generated alternatively or in combination with them by other devices separate from the BSs 30 of the RAN.

[0060] As discussed above, the present disclosure aims to propose a solution that enables better control of the signaling overhead by a RAN when multiple RA procedures are initiated simultaneously by wireless devices, such as A-IoT devices 25.

[0061] To this end, it is proposed to enable the RAN to halt (or not halt) an RA procedure initiated by a wireless device 25 by sending to that wireless device 25 information to authorize direct access, indicating whether the RA procedure should be continued by the wireless device 25. For example, the RAN can decide to halt an RA procedure initiated by a wireless device 25 if the RAN's utilization level is high, if the direct access identifier selected by the wireless device 25 conflicts with (i.e., is the same as) a direct access identifier selected by another wireless device, and so on.Thus, the RAN can control the number of parallel RA procedures and / or the number of collisions to be resolved by transmitting the information for authorizing direct access, thereby reducing the signaling overhead for the RAN and the power consumption for the wireless devices 25.

[0062] The authors then consider a non-restrictive case of competition-based RA procedures initiated simultaneously by several wireless devices 25.

[0063] The authors now present non-restrictive examples of methods for exchanging data in a wireless communication system.

[0064] Fig. Figure 4 presents a diagram illustrating the main steps of a method 40 for exchanging data, implemented by a wireless device 25 of a UE 20. Fig. Figure 5 presents a diagram illustrating the key steps of a method 50 for exchanging data, implemented by a RAN NN, e.g., by a BS 30, or by an intermediate device 31 that relays data between wireless devices 25 and a BS 30. Hereinafter, the authors consider, in a non-restrictive manner, that the NN is a BS 30.

[0065] As through Fig. As illustrated in Figure 4, the data exchange procedure 40 includes a step S40 of selecting, by the wireless device 25, a direct access identifier to initiate a RA procedure with the RAN. In the figures, the selected direct access identifier is denoted RA-ID. For example, the direct access identifier RA-ID is generated randomly by the wireless device 25 and / or it is generated by using some input information, which may include, for example, an identifier of the wireless device 25 that may be specific to that wireless device 25 or to a group of wireless devices containing that wireless device 25.

[0066] It is noted that any suitable format can be used for the direct access identifier RA-ID and that the choice of a specific format corresponds to a specific, but not limiting, embodiment of the present disclosure. For example, the direct access identifier RA-ID can be composed of 16 bits or 32 bits.

[0067] In some examples, the wireless device 25 can initiate the RA procedure (and the selection of the direct access identifier RA-ID) in response to receiving a trigger signal for an uplink transmission from the RAN.

[0068] It is noted that any suitable format can be used for the trigger signal for an uplink transmission and that the choice of a specific format corresponds to a specific, but not limiting, embodiment of the present disclosure. For example, the trigger signal for an uplink transmission can be a paging signal.

[0069] In some cases, the RAN can transmit a wake-up signal that switches the wireless device 25 from a sleep mode to an active mode. This is because the wireless device 25 may be placed in a sleep mode to reduce its power consumption. In such a case, the wireless device 25 must enter an active mode to be able to exchange data with the RAN. Such a transition can be triggered by the RAN sending a wake-up signal to the wireless device 25. In such a case, the trigger signal for an uplink transmission can be the same as the wake-up signal that switches the wireless device 25 from a sleep mode to an active mode, or it can be transmitted by the RAN after it has sent a wake-up signal to the wireless device 25.Using the same signal for the wake-up signal and the trigger signal for an uplink transmission reduces the signaling overhead for the RAN compared to using separate signals.

[0070] In other examples, wireless device 25 can initiate the RA procedure (and the selection of the direct access identifier) ​​without being triggered by the RAN. For example, wireless device 25 can initiate the RA procedure in response to the determination that it has received data from a higher layer to be transferred to the RAN, etc.

[0071] As through Fig. As illustrated in Figure 4, the procedure 40 for exchanging data includes a step S41 of initiating the RA procedure by transmitting to the RAN an initial message containing the selected direct access identifier RA-ID.

[0072] As through Fig. As illustrated in Figure 4, the data exchange procedure 40 includes a step S42 of receiving, during the RA procedure, a second message containing information for authorizing direct access from the RAN. In the figures, the direct access authorization information is labeled RA-INFO. As stated above, the direct access authorization information RA-INFO indicates whether continuing the initiated (contest-based) RA procedure is authorized. Thus, if the direct access authorization information RA-INFO indicates that the initiated RA procedure is authorized (“RA-INFO = OK” in the figures), then the data exchange procedure 40 includes a step S43 of continuing the RA procedure. In some examples, continuing the RA procedure involves transmitting a third message to the RAN in response to the authorization of the initiated RA procedure.For example, the third uplink can contain data (e.g., a unique device identifier and / or data from a higher layer).

[0073] If, however, the RA-INFO authorizing direct access information indicates that the initiated RA procedure is not authorized (“RA-INFO = NOK” in the figures), then the data exchange procedure 40 includes a step S44 of halting the RA procedure. In some examples, the RA procedure can be halted completely, such that the wireless device 25 must initiate a different RA procedure, for example, by selecting a different direct access identifier and sending the newly selected direct access identifier in a first message transmitted to the RAN. In other examples, the RA procedure can be temporarily halted, such that the wireless device 25 can suspend the RA procedure for a period of time, for example, until it receives a second message containing RA-INFO authorizing direct access information indicating that the initiated RA procedure is authorized.

[0074] As stated above, in some cases a contest-based RA procedure can be used to establish a communication identifier for the wireless device 25. This communication identifier can then be used when data is to be exchanged between the wireless device 25 and the RAN, for example, for scheduling purposes, to perform a non-contest RA procedure, to trigger a transmission by a specific wireless device through the RAN, etc.

[0075] In some examples, the direct access authorization information can also be used to set a communication identifier for wireless device 25 based on the direct access identifier RA-ID. Direct access authorization information indicating, for example, that the direct access procedure is authorized ("RA-INFO = OK") further indicates that the selected direct access identifier RA-ID should be used by wireless device 25 as its communication identifier. In such examples, when the direct access authorization information indicates that the RA procedure is authorized, wireless device 25 sets the communication identifier to be used to the direct access identifier RA-ID.

[0076] As discussed above, Fig. Figure 5 shows a diagram illustrating the main steps of the data exchange procedure 50, which can be implemented by a NN (i.e., a BS 30 or an intermediate device 31) when the wireless device 25 uses the data exchange procedure 40, which is implemented by Fig. As illustrated in Figure 4, it is implemented. As discussed above, the authors subsequently consider, in a non-restrictive manner, that the NN is a BS 30.

[0077] As through Fig. As illustrated in Figure 5, the data exchange procedure 50 includes a step S50 of receiving, from the wireless device 25, the first message initiating the RA procedure (which contains the direct access identifier RA-ID selected by the wireless device 25).

[0078] As through Fig. As illustrated in Figure 5, the data exchange procedure 50 includes a step S51 of determining RA-INFO authorization information by evaluating a direct access authorization criterion. Essentially, the evaluation of the direct access authorization criterion aims to determine whether the RA procedure initiated by the wireless device 25 can be continued by that wireless device 25. When the direct access authorization criterion is verified (reference S51a in Figure 50), the RA procedure can be continued by the wireless device 25. Fig. 5), then the information for authorizing direct access is set to “OK” (step S52), indicating that the continuation of the RA procedure by the wireless device 25 has been authorized. However, if the criterion for authorizing direct access is not verified (reference S51b in Fig. 5), then the information for authorizing direct access to “NOK” is determined (step S53), indicating that the continuation of the RA procedure by the wireless device 25 has not been authorized.

[0079] It is noted that any suitable format can be used for the RA-INFO authorization information and that the choice of a specific format corresponds to a specific, but not limiting, embodiment of the present disclosure. In preferred embodiments, a single bit is used to encode the RA-INFO authorization information. For example, a value of '0' for the RA-INFO authorization information indicates that the initiated RA procedure is authorized, and a value of '1' for the RA-INFO authorization information indicates that the initiated RA procedure is not authorized.

[0080] It is also noted that any criterion for authorizing direct access can be used to determine the information for authorizing direct access RA-INFO, and that the choice of a specific criterion for authorizing direct access corresponds to a specific, but not restrictive, embodiment of the present disclosure.

[0081] In some examples, the direct access authorization criterion can be evaluated by comparing the selected direct access identifier (RA-ID) received by wireless device 25 with direct access identifiers received by other wireless devices within the radio coverage area of ​​BS 30. For example, if the selected direct access identifier (RA-ID) differs from all direct access identifiers selected by other wireless devices, no collision is detected. In such a case, the direct access authorization criterion is verified, and the continuation of the RA procedure initiated by wireless device 25 is authorized. However, if the selected direct access identifier (RA-ID) has also been selected by another wireless device within the radio coverage area of ​​BS 30, then a collision is detected.In such a case, the criterion for authorizing direct access is not verified and the continuation of the RA procedure initiated by the wireless device 25 is not authorized.

[0082] Alternatively, or in combination with this, the criterion for authorizing direct access can be evaluated in some examples by using a BS 30 utilization level. For example, if the BS 30 utilization level is low (e.g., lower than a predefined first threshold), then the criterion for authorizing direct access is verified, and the continuation of the RA procedure initiated by the wireless device 25 is authorized. Conversely, if the BS 30 utilization level is high (e.g., greater than a predefined second threshold that is greater than or equal to the first threshold), then the criterion for authorizing direct access is not verified, and the continuation of the RA procedure initiated by the wireless device 25 is not authorized.

[0083] It is noted that any suitable method may be used to estimate the utilization rate of BS 30, and that the choice of a specific method for estimating a utilization rate corresponds to a specific, but not limiting, embodiment of the present disclosure. For example, the utilization rate of BS 30 may correspond to one of the following parameters or a combination of two or more of the following parameters: - Number of wireless devices connected to the BS 30: 25 - Number of wireless devices 25 that successfully attempted to access the RAN or BS 30 within a predefined time period, - Number of wireless devices 25 that were blocked from accessing the RAN or BS 30 within a predefined period, - Number of initial messages from RA proceedings received by BS 30 within a predefined period, - Packet buffer status of BS 30, - average time that packages remain in the package buffer, - Ratio of connected A-IoT devices / non-A-IoT devices, - Parameters that represent the use of communication resources (e.g., a ratio of used communication resources to total communication resources), - etc.

[0084] As through Fig. As illustrated in Figure 5, the procedure 50 for exchanging data includes a step S54 of transmitting the specific information to authorize direct access RA-INFO to the wireless device 25 during the RA procedure.

[0085] Fig. Figure 6 presents a flowchart illustrating examples of message sequences exchanged between a wireless device 25 of a UE 20 and a network node (the BS 30 in these examples) during a RA procedure. These examples adopt, in a non-restrictive manner, the 3-step RA procedure discussed above with respect to A-IoT devices. As discussed above, this 3-step RA procedure comprises the following: - an initial message (“MSG1” in the figures) transmitted by the wireless device 25 to the BS 30 (step S41), containing a direct access identifier RA-ID generated by the wireless device 25 (step S40), - a second message (“MSG2” in the figures) transmitted by the BS 30 to the wireless device 25, which reflects the direct access identifier RA-ID (“ACK[RA-ID]” in the figures), - a third message (“MSG3” in the figures) transmitted by the wireless device 25 to the BS 30, containing uplink data (e.g. a unique device identifier and / or higher layer data).

[0086] As discussed above, the RA procedure may optionally include a fourth message (“ACK[MSG3]” in the figures). If present, the fourth message may, for example, be used to handle a transmission error in the third message, MSG3.

[0087] In the example of Fig. 6. The information for authorizing direct access RA-INFO is contained in the second message MSG2 and is transmitted by the BS 30 together with the direct access identifier RA-ID, which is received by the wireless device 25.

[0088] In part a) of Fig. 6. The RA procedure is approved by BS 30, and the RA-INFO direct access approval information indicates that the continuation of the RA procedure initiated by wireless device 25 is approved (“RA-INFO = OK”). Thus, wireless device 25 continues the RA procedure by transmitting a third message MSG3 (and BS 30 responds, if necessary, by transmitting a fourth message ACK[MSG3]).

[0089] In part b) of Fig. 6. A first RA procedure is not authorized by the BS 30, and the RA-INFO authorization information indicates that continuing the first RA procedure initiated by the wireless device 25 is not authorized (“RA-INFO = NOK”). Thus, the wireless device 25 stops the first RA procedure and does not transmit a third message MSG3 in response to the second message MSG2 received by the BS 30.

[0090] In the non-restrictive, by part b) of Fig.In the illustrated example 6, when the first RA procedure is stopped, the wireless device 25 initiates a second RA procedure by selecting a new direct access identifier RA-ID' and transmitting an initial message containing the new direct access identifier RA-ID' to the BS 30. This second RA procedure can be initiated by the wireless device 25, for example, immediately after the first RA procedure is stopped, after waiting for a predefined period, or in response to another trigger signal for an uplink transmission transmitted by the BS 30, etc. The second RA procedure is authorized by the BS 30, and the direct access authorization information RA-INFO indicates that the continuation of the second RA procedure initiated by the wireless device 25 is authorized ("RA-INFO = OK").Thus, the wireless device 25 continues the second RA process by transmitting a third message MSG3 (and the BS 30 responds, if necessary, by transmitting a fourth message ACK[MSG3]).

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

[0092] For example, the present disclosure was prepared primarily with consideration of the case of A-IoT devices. However, the present disclosure can also be used for non-A-IoT devices.

[0093] It is also noted that in the wireless communication system there may be a coexistence of wireless devices 25 that apply the present disclosure and wireless devices that do not apply the present disclosure. For example, the present disclosure may apply only to A-IoT devices and not to non-A-IoT devices.

Claims

[1] Method (40) for exchanging data in a wireless communication system, wherein the method is implemented by a wireless device (25) of the wireless communication system, the wireless device comprising a communication unit configured to exchange data with a radio access network (RAN) of the wireless communication system, the method comprising: - (S40) Selecting a direct access identifier, - (S41) Initiating a direct access procedure by transmitting an initial message to the RAN, the initial message containing the selected direct access identifier, - (S42) Receiving a second message from the RAN, wherein the second message contains the selected direct access identifier and the information for authorizing direct access, - in response to the information for authorizing direct access indicating that the direct access procedure is not authorized: (S44) Stop the direct access procedure, - in response to the information for authorizing direct access indicating that the direct access procedure is authorized: (S43) Continue the direct access procedure. [2] Method (40) according to claim 1, wherein continuing the direct access method comprises transmitting a third message to the RAN in response to the second message, wherein the third message contains uplink data. [3] Method (40) according to any of the preceding claims, comprising, in response to the fact that the direct access authorization information indicates that the direct access procedure is not authorized: selecting a different direct access identifier and initiating a different direct access procedure. [4] Method (40) according to any of the preceding claims, wherein the information for authorizing direct access corresponds to a single bit. [5] Method (40) according to claim 4, wherein a value of 0 of the information for authorizing direct access indicates that the direct access method is authorized, and a value of 1 of the information for authorizing direct access indicates that the direct access method is not authorized. [6] Wireless device (25) comprising at least one memory and at least one processor configured to perform a method (40) according to any of the preceding claims. [7] User equipment (UE) (20) comprising a wireless device according to claim 6. [8] Method (50) for exchanging data in a wireless communication system, wherein the method is implemented by a network node (NN) (30) of a radio access network (RAN) of the wireless communication system, the method comprising: - (S50) Receiving, from a wireless device, a first message of a direct access method, wherein the first message contains a direct access identifier, - (S54) Transmitting a second message to the wireless device in response to the first message, the second message containing the received direct access identifier and direct access authorization information indicating whether the wireless device should continue the direct access procedure. [9] Method (50) according to claim 8, comprising, if the transmitted information for authorizing direct access indicates that the direct access method is to be continued, receiving a third message from the wireless device, wherein the third message contains uplink data. [10] Method (50) according to any one of claims 8 to 9, comprising (S51) determining the information for authorizing direct access by evaluating a criterion for authorizing direct access. [11] Method (50) according to claim 10, wherein the criterion for authorizing direct access is evaluated by using a utilization level of the NN. [12] Method (50) according to one of claims 10 to 11, wherein the criterion for authorizing direct access is evaluated by comparing the direct access identifier received by the wireless device with direct access identifiers received by other wireless devices. [13] Method (50) according to any one of claims 8 to 12, wherein the information for authorizing direct access corresponds to a single bit. [14] Method (50) according to claim 13, wherein a value of 0 of the information for authorizing direct access indicates that the direct access method is authorized, and a value of 1 of the information for authorizing direct access indicates that the direct access method is not authorized. [15] Network node (NN) (30) comprising at least one memory and at least one processor configured to perform a method (50) according to any one of claims 8 to 14. [16] Wireless communication system comprising at least one network node (30) according to claim 15 and at least one user device (20) according to claim 7.

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