Method and device for enhancing the usage of random-access uplink resources by allocating different sets of uplink resources to different ambient IoT devices

Abstract

The present disclosure relates to methods and devices for reducing collision probability on uplink resources by enabling a user equipment, UE (20), for example an ambient-loT device, having a UE identity known to a radio access network, RAN, to use a first set of uplink resources different from a second set of uplink resources used by a UE (20) not having a UE identity known to the RAN.

Description

Method and device for enhancing the usage of random-access uplink resources by allocating different sets of uplink resources to different ambient loT devicesTechnical field

[0001] The present disclosure relates to wireless communication systems and relates more specifically to methods and devices for enhancing the usage of random-access uplink resources by wireless devices, for example wireless devices harvesting ambient energy.Background

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

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

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

[0005] In some cases, such A-loT devices may only initiate an uplink transmission when triggered so by the radio access network, RAN. This holds also for random-access uplink resources, i.e., uplink resources which are shared by a plurality of wireless devices, on which each of these wireless devices can decide on its own when to transmit uplink data, which uplink data may therefore collide with uplink data from other wireless devices with which these uplink resources are shared. Such random-access uplink resources on which uplink data from different wireless devices can collide are also referred to as contentionbased uplink resources. Examples of contention-based uplink resources include randomaccess channel, RACH, uplink resources.

[0006] However, the risk of collisions and of congestion of the contention-based uplink resources increases as the number of A-loT devices deployed increases. Also, with many collisions due to A-loT devices willing to access contention-based uplink resources, the radio access network, RAN, might need to trigger retransmissions by the colliding A-loT devices, which would increase the signaling overhead for the RAN.Summary

[0007] The present disclosure aims at improving the situation. In particular, the present disclosure aims at addressing at least some of the limitations of the prior art discussed above. In particular, the present disclosure aims at proposing a solution for reducing the risk of collisions between uplink data from wireless devices, such as A-loT devices, willing to access uplink resources such as random-access uplink resources.

[0008] For that purpose, it is proposed that different sets of uplink resources are allocated to different user equipment, UEs, wherein each UE then selects the set of uplink resources to be used based on whether it has a UE identity known to the RAN. In other words, UEs attempting to transmit uplink data to the RAN for the first time (e.g., newly deployed A-loT device) will use a different set of uplink resources than those UEs which are already known by the RAN, i.e., from the which the RAN already knows that it may receive uplink data. This enables the RAN to reduce or cancel collisions between UEs having a UE identity known to the RAN and UEs which do not have a UE identity known to the RAN.

[0009] According to a first aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, the method being implemented by a user equipment, UE, of the wireless communication system, wherein the UE comprises a communication unit configured to exchange data with a radio access network, RAN, of the wireless communication system, wherein the method comprises: receiving from the RAN an uplink transmission triggering signal used to trigger an uplink transmission by a plurality of UEs, wherein the uplink transmission triggeringsignal includes an indication of at least one first set of uplink resources and at least one second set of uplink resources, wherein the at least one second set of uplink resources is different from the at least one first set of uplink resources, evaluating whether the UE has a UE identity known to the RAN, in response to the UE having a UE identity known to the RAN: using the at least one first set of uplink resources for performing an uplink transmission, in response to the UE not having a UE identity known to the RAN: using the at least one second set of uplink resources for performing the uplink transmission.

[0010] In some embodiments, the method according to the first aspect can further comprise one or more of the following optional features, considered either alone or in any technically possible combination.

[0011] In some embodiments of the method according to the first aspect, the at least one first set of uplink resources and the at least one second set of uplink resources correspond to random-access uplink resources.

[0012] In some embodiments of the method according to the first aspect, the at least one first set of uplink resources corresponds to contention free uplink resources and the at least one second set of uplink resources corresponds to contention-based uplink resources.

[0013] In some embodiments of the method according to the first aspect, the uplink transmission triggering signal includes an indication of a plurality of first sets of uplink resources and / or a plurality of second sets of uplink resources.

[0014] In some embodiments of the method according to the first aspect, the uplink transmission triggering signal includes an indication of a plurality of first sets of uplink resources together with a plurality of first set identifiers associated to different UEs having UE identities known to the RAN, and the method further comprises, in response to the UE having a UE identity known to the RAN, retrieving the first set identifier associated to said UE and selecting, among the plurality of first sets of uplink resources, the first set of uplink resources identified by the retrieved first set identifier for performing the uplink transmission.

[0015] In some embodiments of the method according to the first aspect, the uplink transmission triggering signal is a paging message and / or a wake-up signal transmitted by the RAN that transitions the UE from a sleep mode to an active mode.

[0016] In some embodiments of the method according to the first aspect, the UE comprises an energy harvesting unit configured to convert ambient energy into electrical energy that is stored in an energy storage unit of the UE.

[0017] According to a second aspect, the present disclosure relates to a user equipment, UE, comprising at least one memory and at least one processor configured to carry out amethod according to any one of the embodiments of the first aspect.

[0018] According to a third aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, the method being implemented by a base station, BS, of a radio access network, RAN, of the wireless communication system, wherein the BS is configured to exchange data with a plurality of user equipment, UEs, wherein the method comprises transmitting to the plurality of UEs an uplink transmission triggering signal which comprises an indication of at least one first set of uplink resources and at least one second set of uplink resources to be used during an uplink transmission, wherein the at least one second set of uplink resources is different from the at least one first set of uplink resources, wherein the at least one first set of uplink resources is to be used by UEs having an UE identity known to the RAN and the at least one second set of uplink resources is to be used by UEs not having an UE identity known to the RAN.

[0019] In some embodiments, the method according to the third aspect can further comprise one or more of the following optional features, considered either alone or in any technically possible combination.

[0020] In some embodiments of the method according to the third aspect, the at least one first set of uplink resources and the at least one second set of uplink resources correspond to random-access uplink resources.

[0021] In some embodiments of the method according to the third aspect, the at least one first set of uplink resources corresponds to contention free uplink resources and the at least one second set of uplink resources corresponds to contention-based uplink resources.

[0022] In some embodiments of the method according to the third aspect, the uplink transmission triggering signal includes an indication of a plurality of first sets of uplink resources and / or a plurality of second sets of uplink resources.

[0023] In some embodiments of the method according to the third aspect, the uplink transmission triggering signal includes an indication of a plurality of first sets of uplink resources together with a plurality of first set identifiers associated to different UEs having UE identities known to the RAN, to be used by the UEs having UE identities for selecting a first set of uplink resources among the plurality of first sets of uplink resources.

[0024] In some embodiments of the method according to the third aspect, the uplink transmission triggering signal is a paging message and / or a wake-up signal that transitions the plurality of UEs from a sleep mode to an active mode.

[0025] In some embodiments of the method according to the third aspect, each of the plurality of UEs comprises an energy harvesting unit configured to convert ambient energy into electrical energy that is stored in an energy storage unit of the UE.

[0026] According to a fourth aspect, the present disclosure relates to a base station, BS, comprising at least one memory and at least one processor configured to carry out a method according to any one of the embodiments of the third aspect.

[0027] According to a fifth aspect, the present disclosure relates to a wireless communication system comprising at least one base station according to any one of the embodiments of the present disclosure and at least one user equipment according to any one of the embodiments of the present disclosure.

[0028] According to a sixth aspect, the present disclosure relates to a computer program product comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method for exchanging data according to any one of the embodiments of the present disclosure. The computer program product can use any programming language, and can be in the form of source code, object code, or in any intermediate form between source code and object code, such as in a partially compiled form, or in any other desirable form.

[0029] According to a seventh aspect, the present disclosure relates to a (non-transitory) computer-readable storage medium comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method for exchanging data according to any one of the embodiments of the present disclosure.Brief description of figures

[0030] The invention will be better understood upon reading the following description, given as an example that is in no way limiting, and made in reference to the figures which show:Figure 1 : schematic representations of different possible topologies of a wireless communication system,Figure 2: a schematic representation of an example of a UE, Figure 3: a schematic representation of an example of a BS, Figures 4 and 5: flow charts illustrating examples of methods for exchanging data implemented by a UE and a BS, respectively.

[0031] In these figures, references identical from one figure to another designate identical or analogous elements. For reasons of clarity, the elements shown are not to scale, unless explicitly stated otherwise.Detailed description

[0032] The detailed description set forth below, with reference to the figures, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understandingof the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. For instance, although 3GPP terminology, from e.g., 5G NR, may be used in this disclosure to exemplify embodiments herein, this should not be seen as limiting the scope of the present disclosure.

[0033] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. Also, the order of steps of any methods disclosed herein, in particular in the figures, is provided only for illustration purposes and is not meant to limit the present disclosure which may be applied with the same steps executed in a different order and / or with all or part of the steps executed in parallel or jointly, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Also, in a figure, steps represented surrounded by a dashed line are to be considered as optional for the embodiment represented in this figure. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

[0034] Figure 1 represents schematically an example of wireless communication system, which may be for example a 5G NR wireless communication system. More specifically, figure 1 represents a RAN of the wireless communication system, which is used exchange data with UEs 20 via radio signals. For example, the RAN may send data to the UEs 20 (downlink, DL), for instance data received from a core network (CN, not represented in the figures). The RAN may also receive data from the UEs 20 (uplink, UL), which data may be forwarded to the CN.

[0035] In the example illustrated by figure 1 , the RAN comprises one base station, BS, 30. Of course, the RAN may comprise more than one BS 30 to increase the coverage of the wireless communication system. Each of these BSs may be referred to as NB, eNodeB (or eNB), gNodeB (or gNB, in the case of a 5G NR wireless communication system), an access point or the like, depending on the wireless communication standard(s) implemented.

[0036] In the example illustrated by figure 1 , only one UE 20 is represented, which includes a wireless device 25 that provides the UE 20 with wireless connectivity to the RAN of the wireless communication system. Part a) of figure 1 represents schematically an example inwhich the UE 20 exchanges data (useful data and control data) directly with a BS 30 of the RAN (referred to as Topology 1 in TR 38.848 V18.0.0). Part b) of figure 1 represents schematically an example in which the UE 20 exchanges data (useful data and control data) indirectly with a BS 30 of the RAN, via one or more intermediate nodes 31 (referred to as Topology 2 in TR 38.848 V18.0.0). Each intermediate node 31 may be e.g., a relay, an integrated access and backhaul (I AB) node, another UE 20, a repeater, a reconfigurable intelligent surface (RIS), etc.

[0037] Figure 2 represents schematically an example of a wireless device 25 suitable for implementing any method, discussed in the present disclosure, performed at a UE 20. Basically, the wireless device 25 corresponds to an apparatus that provides wireless connectivity with the RAN of the wireless communication system, and that can be used to exchange data with said RAN. The wireless device 25 is for example an A-loT device, i.e. , a wireless device having a peak power consumption lower than 1 mW, or even lower than 100 pW, or even lower than 10 pW.

[0038] Such a wireless device 25 may be included in a UE 20, as illustrated by figure 2. The UE 20 may for instance be a cellular phone, a wireless modem, a wireless communication device, a handheld device, a laptop computer, or the like. In preferred examples, the UE 20 may also be an Internet of Things (loT) equipment, like a wireless camera, a smart sensor, a smart meter, smart glasses, a vehicle (manned or unmanned), a global positioning system device, etc., or any other equipment that may run applications that need to exchange data with remote recipients, via the wireless device 25.

[0039] As illustrated by figure 2, the wireless device 25 comprises one or more processors 250 and one or more memories 251. The one or more processors 250 may include for instance a central processing unit (CPU), a digital signal processor (DSP), a field- programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc. The one or more memories 251 may include any type of computer readable volatile and nonvolatile memories (magnetic hard disk, solid-state disk, optical disk, electronic memory, etc.). The one or more memories 251 may store a computer program product 252, in the form of a set of program-code instructions to be executed by the one or more processors 250 to implement all or part of the steps of a method for exchanging data, performed at a UE’s side, according to any one of the embodiments disclosed herein.

[0040] As illustrated by figure 2, the wireless device 25 comprises also a (wireless) communication unit 253 configured to exchange data (directly or indirectly) with BSs 30 of the RAN using radio signals. The communication unit 253 may implement one or more wireless communication protocols, and may for instance be a 3G, 4G, 5G, NR, WiFi, WiMax,etc. transceiver or the like. In preferred embodiments, the (wireless) communication unit 253 comprises a 5G NR wireless communication unit.

[0041] As discussed above, the communication unit 253 may comprise in some examples neither downlink (DL) nor uplink (UL) amplification capabilities (the UL transmission is backscattered on a carrier wave provided externally). In other examples, the communication unit 253 may comprise DL and / or UL amplification (the UL transmission may be generated internally by the wireless device or be backscattered on a carrier wave provided externally).

[0042] In the non-limitative example illustrated by figure 2, the wireless device 25 comprises also an energy harvesting unit 254 and an energy storage unit 255 of the wireless device.

[0043] The energy storage unit 255 may be any type of electrical energy accumulator, and may comprise e.g., one or more capacitors, one or more batteries, etc. The energy storage unit 255 is used to provide electrical energy to the other equipment of the wireless device 25 which require electrical energy, such as the one or more processors 250, the one or more memories 251 and, in some examples, the (wireless) communication unit 253.

[0044] The energy harvesting unit 254 is configured to convert ambient energy into electrical energy that is stored in the energy storage unit 255. By “ambient energy” we mean energy from energy sources that are external to the wireless device 25, which is received at the wireless device 25 without any wires between the energy sources and the wireless device 25. Hence, the energy harvesting unit 254 is such that the wireless device 25 may operate in an autonomous manner, without having to replace or recharge manually the energy storage unit 255. The energy harvesting unit 254 may for example collect energy from various energy sources including solar, thermal, motion or vibration, radiofrequency (RF), etc.

[0045] In preferred embodiments, the energy harvesting unit 254 comprises at least a radio unit configured to convert RF signals into electrical energy that is stored in the energy storage unit 255. These RF signals may for instance be external RF signals, i.e., RF signals which do not originate from within the wireless communication system itself but from RF sources which are external to the wireless communication system. For example, external RF signals may originate from external 3G, 4G, 5G, NR, WiFi, WiMax, Bluetooth, DAB, etc., devices located in the vicinity of the wireless device 25. Alternatively, or in combination thereof, the RF signals may originate from within the wireless communication system, for example from BSs 30 of the RAN which may transmit an energy harvesting (RF) signal to (A-loT) wireless devices 25 in their coverage, and / or from equipment separate from the BSs 30 but deployed to enable energy harvesting at the (A-loT) wireless devices 25 of the wireless communication system. In some examples, when RF signals are used to collectelectrical energy into the energy storage unit 255, the energy harvesting unit 254 may be included in the (wireless) communication unit 253.

[0046] In some examples, the electrical energy collected by the energy harvesting unit 254 may be provided directly to the other equipment of the wireless device 25, in which case the energy storage unit 255 is optional and needs not to be included in the wireless device.

[0047] Figure 3 represents schematically an example of a BS 30 suitable to implement any method, discussed in the present disclosure, performed by the RAN.

[0048] As illustrated by figure 3, the BS 30 comprises one or more processors 300 and one or more memories 301. The one or more processors 300 may include for instance a central processing unit (CPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc. The one or more memories 301 may include any type of computer readable volatile and non-volatile memories (magnetic hard disk, solid-state disk, optical disk, electronic memory, etc.). The one or more memories 301 may store a computer program product 302, in the form of a set of programcode instructions to be executed by the one or more processors 300 to implement all or part of the steps of a method for exchanging data, performed at the RAN’s side, according to any one of the embodiments disclosed herein.

[0049] As illustrated by figure 3, the BS 30 comprises also a wireless communication unit 303, configured to exchange data with UEs 20 using radio signals, and more specifically with (wireless) communication units 253 of wireless devices 25 included in these UEs 20. The wireless communication unit 303 may for instance be a 3G, 4G, 5G, NR, WiFi, WiMax, etc. transceiver or the like. In preferred embodiments, the wireless communication unit 303 of the BS 30 comprises a 5G NR transceiver. In some examples, the wireless communication unit 303 may also transmit carrier waves to the wireless devices 25 which perform uplink backscattering transmissions.

[0050] As illustrated by figure 3, the BS 30 may comprise also, in some examples, a network communication unit 304, configured to exchange data with other base stations of the RAN and / or with the CN. The network communication unit 305 may support one or more suitable communication protocols, which may be wired (including optical) and / or wireless.

[0051] As illustrated by figure 3, the BS 30 may comprise also, in some examples, an energy harvesting signal generator 305, which generates energy harvesting (RF) signals which enable wireless devices 25 in its coverage to collect electrical energy in their energy storage units 255, via their energy harvesting units 254. The energy harvesting (RF) signals may take any suitable form enabling the energy harvesting units 254 to store electrical energy in the energy storage units 255 of the wireless devices 25. The choice of a specificenergy harvesting (RF) signal format consists in a specific and non-limitative embodiment of the present disclosure. As mentioned above, when present, such energy harvesting (RF) signals may alternatively, or in combination thereof, be generated by other equipment separate from BSs 30 of the RAN.

[0052] As discussed above, the present disclosure aims at proposing a solution for reducing the risk of collisions between uplink data from UEs 20, such as A-loT devices, willing to access uplink resources such as random-access uplink resources.

[0053] For that purpose, it is proposed that different sets of uplink resources are allocated to different UEs 20. More specifically, at least one first set of uplink resources is allocated to UEs 20 having UE identities known to the RAN and at least one second set of uplink resources, different from the at least one first set of uplink resources, is allocated to UEs 20 not having UE identities known to the RAN. Then, each UE 20 selects the set of uplink resources to be used based on whether it has a UE identity known to the RAN. In other words, UEs attempting to transmit uplink data to the RAN for the first time (e.g., newly deployed A-loT device) will use the at least one second set of uplink resources while UEs 20 which are already known by the RAN (i.e. , from the which the RAN already knows that it may receive uplink data) will use the at least one first set of uplink resources. This enables the RAN to reduce or cancel collisions between UEs having a UE identity known to the RAN and UEs which do not have a UE identity known to the RAN.

[0054] For example, the UE identity known to the RAN may be an identity assigned to the UE 20 by the RAN and / or an identity previously transmitted to the RAN by the UE 20.

[0055] For example, the identity assigned to the UE 20 by the RAN may correspond to a temporary mobile subscriber identity, TMSI, a 5G-S-TMSI, a 5G globally unique temporary identity, 5G-GUTI, a random identity generated by the RAN, etc., or any new type of identity that may be assigned by the RAN to identify A-loT devices. For example, the identity transmitted to the RAN by the UE 20 may correspond to an international mobile subscriber identity, I MSI , an international mobile equipment identity, I M El , a random identity generated by the UE 20, etc., or any new type of identity that may be associated to the UE 20 as an A-loT device that said UE 20 may share with the RAN.

[0056] In some examples, the UE identity known to the RAN may correspond to a UE contention resolution identity received during a previous successful access on contentionbased uplink resources. In the current RACH procedures of the existing version of the 5G NR standard, the UE contention resolution identity is typically received in the message Msg4 (in case of a 4-step RACH procedure) or in the message MsgB (in case of a 2-step RACH procedure). However, other RACH procedures may be defined for A-loT devices.

[0057] It should be noted that the different sets of uplink resources can be allocated implicitly by the RAN, i.e., the RAN does not need to tell explicitly each UE 20 which set of uplink resources it should use. Indeed, it is sufficient for the UEs 20 to be able to determine which set(s) of uplink resources are to be used by UEs 20 having a UE identity known to the RAN and which set(s) of uplink resources are to be used by UEs 20 not having a UE identity known to the RAN. Then, each UE 20 may determine on its own which set of uplink resources to be used based on whether it has a UE identity known to the RAN.

[0058] Hence, the important aspect is whether the RAN is aware of the presence of a specific UE 20 in its coverage, in which case said RAN already has access to a UE identity for this specific UE 20, which UE identity may be temporary or permanent, received from this specific UE 20 or assigned to this specific UE 20 by the RAN, etc. Hence, the RAN is aware of the presence of the UEs 20 which may use the at least one first set of uplink resources while it is not aware of the presence if the UEs 20 which may use the at least one second set of uplink resources.

[0059] For example, the uplink resources (composing a first or second set) comprise one or more time intervals during which the UE 20 should transmit, or one or more carrier frequencies the UE 20 should use, or a combination thereof. In some examples, the uplink resources can comprise, alternatively or in combination thereof, one or more codes (e.g., RACH preambles, etc.) the UE 20 should use.

[0060] For example, the at least one first set of uplink resources and the at least one second set of uplink resources correspond to random-access uplink resources.

[0061] In some examples, the at least one first set of uplink resources corresponds to contention free uplink resources and the at least one second set of uplink resources corresponds to contention-based uplink resources.

[0062] As discussed above, the at least one first set of uplink resources and the at least one second set of uplink resources are different, to reduce collision probability between UEs 20 having a UE identity known to the RAN and UEs 20 which do not have UE identities known to the RAN. By “different”, we mean that there exist uplink resources in the at least one first set of uplink resources that do not belong to the at least one second set of uplink resources and / or that there exist uplink resources of the at least one second set of uplink resources that do not belong to the at least one first set of uplink resources.

[0063] In preferred embodiments, the at least one first set of uplink resources and the at least one second set of uplink resources are separate. By “separate”, we mean that there are no uplink resources which are both in the at least one first set of uplink resources and in the at least one second set of uplink resources, such that uplink transmissions from UEs20 having a UE identity known to the RAN cannot collide with uplink transmissions from UEs 20 which do not have UE identities known to the RAN.

[0064] Figure 4 represents a diagram showing steps of an exemplary embodiment of a method 40 for exchanging data, which is implemented by a UE 20. Figure 5 represents a diagram showing corresponding steps of an exemplary embodiment of a method 50 for exchanging data, which is implemented by a BS 30 of the RAN.

[0065] As illustrated by figure 4, the method 40 for exchanging data comprises a step S40 of receiving from the RAN an uplink transmission triggering signal. Such an uplink transmission triggering signal is a broadcast or multicast signaling message that will trigger an uplink transmission by a plurality of UEs 20.

[0066] For example, the uplink transmission triggering signal may be a paging message.

[0067] Alternatively, or in combination thereof, the uplink transmission triggering signal may be a wake-up signal transmitted by the RAN that transitions the UEs 20 from a sleep mode to an active mode, or a signaling message transmitted after such a wake-up signal. Indeed, to reduce its electrical energy consumption, the UE 20 (or at least its wireless device 25) may be placed in a sleep mode. In such a case, the UE 20 needs to transition to an active mode to be able to exchange data with the RAN. Such a transition may be triggered by the RAN, by sending a wake-up signal to the UE 20. In such a case, the uplink transmission triggering signal, if any, may correspond to the wake-up signal which transitions the UE 20 from a sleep mode to an active mode, or it may be transmitted by the RAN after the RAN has transmitted a wake-up signal to the UE 20. Using a same signal for the wake-up signal and the uplink transmission triggering signal reduces the signaling overhead for the RAN, compared to using separate signals.

[0068] The uplink transmission triggering signal, received during step S40, comprises an indication of at least one first set of uplink resources and at least one second set of uplink resources, wherein the at least one second set of uplink resources is different from the at least one first set of uplink resources. In preferred examples, the at least one second set of uplink resources is separate from the at least one first set of uplink resources.

[0069] As discussed above, the at least one first set of uplink resources is to be used by UEs 20 having a UE identity known to the RAN, and the at least one second set of uplink resources is to be used by UEs 20 not having a UE identity known to the RAN. Hence, the UEs 20 need to be able to identify which indicated set of uplink resources is a first set of uplink resources and which indicated set of uplink resources is a second set of uplink resources.

[0070] The distinction between first set(s) of uplink resources and second set(s) of uplinkresources may be implicit. For example, the signaling message transmitted by the RAN may be configured to indicate first the first set(s) of uplink resources and then the second set(s) of uplink resources, i.e. , the distinction between first set(s) of uplink resources and second set(s) of uplink resources is based on their position in the signaling message. If there are a plurality of first sets of uplink resources and / or a plurality of second sets of uplink resources, the RAN may e.g. include in the signaling message the number of first sets of uplink resources and / or the number of second sets of uplink resources indicated in said signaling message.

[0071] Alternatively, or in combination thereof, the distinction between first set(s) of uplink resources and second set(s) of uplink resources may be explicit. For example, the signaling message transmitted by the RAN may include, for each indicated set of uplink resources, an information on whether the indicated set of uplink resources is a first set of uplink resources (to be used by UEs 20 having a UE identity known to the RAN) or a second set of uplink resources (to be used by UEs 20 not having a UE identity known to the RAN). For example, this information may consist in a single bit, wherein a bit value of ‘0’ may designate a first set of uplink resources and a bit value of T may designate a second set of uplink resources. According to another example, the signaling message transmitted by the RAN may include such an information only for first set(s) of uplink resources (i.e., a set of uplink resources is a first set of uplink resources if explicitly mentioned as such, otherwise it is a second set of uplink resources).

[0072] The indication of a (first or second) set of uplink resources may use any suitable format and the choice of a specific format corresponds to a specific but non-limitative embodiment of the present disclosure.

[0073] In some examples, there may be a plurality of first sets of uplink resources and / or a plurality of second sets of uplink resources. For example, the first sets of uplink resources and the second sets of uplink resources may be separate. In case of a plurality of first sets of uplink resources, then they may be all different but not separate, or they may be all separate, or some of them may be different with some overlap while the others may be separate. Similarly, in case of a plurality of second sets of uplink resources, then they may be all different but not separate, or they may be all separate, or some of them may be different with some overlap while the others may be separate.

[0074] In some examples, regardless of whether the sets of uplink resources are separate, the amount of uplink resources in the at least one first set of uplink resources is preferably greater than the amount of uplink resources in the at least one second set of uplink resources. In other words, UEs 20 having UE identities known to the RAN will tend to beprioritized over UEs 20 not having UE identities known to the RAN since they will have access to more uplink resources.

[0075] As discussed above, the different sets of uplink resources can be allocated implicitly by the RAN, i.e., the RAN does not need to tell explicitly each UE 20 which set of uplink resources it should use. Indeed, it is sufficient for the UEs 20 to be able to determine which set(s) of uplink resources are to be used by UEs 20 having a UE identity known to the RAN and which set(s) of uplink resources are to be used by UEs 20 not having a UE identity known to the RAN.

[0076] In examples which comprise a plurality of first sets of uplink resources (resp. a plurality of second sets of uplink resources), each UE 20 can for example select one of the first (resp. second) set of uplink resources unilaterally, for example randomly. It is also possible, in other examples, to use a preconfigured mapping between the plurality of first (resp. second) sets of uplink resources and respective different priority levels. In such a case, each UE 20 can for example select one of the first (resp. second) sets of uplink resources based on a priority level of the uplink data said UE 20 will transmit to the RAN.

[0077] In examples which comprise a plurality of first sets of uplink resources, to be used by UEs 20 having UE identities known to the RAN, it is also possible for the RAN to explicitly allocate the plurality of first sets of uplink resources to respective UEs 20 or groups of UEs 20 having UE identities known to the RAN. In other words, the RAN may explicitly indicate to each UE 20 (or group of UEs 20) having a UE identity known to the RAN which first set of uplink resources it shall use among the plurality of first sets of uplink resources. For example, the RAN may provide each UE 20 (or group of UEs 20) having a UE identity known to the RAN with a first set identifier which enables said UE 20 to determine which first set of uplink resources it shall use among the plurality of first sets of uplink resources. Such an explicit allocation may result in the uplink resources of the first sets being used as contention free uplink resources by the UEs 20 having UE identities known to the RAN.

[0078] As illustrated by figure 4, the method 40 for exchanging data comprises a step S41 during which the UE 20 evaluates whether it has a UE identity known to the RAN. For example, the UE 20 evaluates whether it has a UE contention resolution identity.

[0079] If the UE 20 has a UE identity known to the RAN (reference S41a in figure 4), for example if the UE 20 has a UE contention resolution identity, then the method 40 for exchanging data comprises a step S42 of using the at least one first set of uplink resources for performing an uplink transmission. If more than one first set of uplink resources is indicated, the UE 20 may select one first set of uplink resources among the plurality of first sets of uplink resources, as discussed above.

[0080] In turn, if the UE 20 does not have a UE identity known to the RAN (reference S41 b in figure 4), for example if the UE 20 does not have a UE contention resolution identity, then the method 40 for exchanging data comprises a step S43 of using the at least one second set of uplink resources for performing an uplink transmission. If more than one second set of uplink resources is indicated, the UE 20 may select one second set of uplink resources among the plurality of second sets of uplink resources, as discussed above.

[0081] For example, using the first or second set of uplink resources comprises performing a RACH procedure by the UE 20.

[0082] As discussed above, figure 5 represents a diagram showing corresponding steps of an exemplary embodiment of a method 50 for exchanging data, which may be implemented by a BS 30 when the UE 20 implements the method 40 for exchanging data illustrated by figure 4.

[0083] As illustrated by figure 5, the method 50 for exchanging data comprises a step S50 of transmitting to a plurality of UEs 20 an uplink transmission triggering signal which includes an indication of at least one first set of uplink resources and at least one second set of uplink resources to be used by the plurality of UEs 20 to perform uplink transmissions.

[0084] As discussed above, the at least one second set of uplink resources is different from the at least one first set of uplink resources, and the at least one first set of uplink resources is to be used by UEs 20 having a UE identity known to the RAN while the at least one second set of uplink resources is to be used by UEs 20 not having a UE identity known to the RAN.

[0085] As discussed above, in some examples, the at least one first set of uplink resources and the at least one second set of uplink resources may be separate.

[0086] As discussed above, any suitable format may be used for the indication of the at least one first set of uplink resources and the at least one second set of uplink resources and the choice of a specific format corresponds to a specific but non-limitative embodiment of the present disclosure. Also, any suitable signaling message type may be used for the uplink transmission triggering signal and the choice of a specific signaling message type corresponds to a specific but non-limitative embodiment of the present disclosure.

[0087] For example, the uplink transmission triggering signal may be a paging message and / or a wake-up signal that transitions the plurality of UEs 20 from a sleep mode to an active mode (or a signaling message transmitted after such a wake-up signal).

[0088] It is emphasized that the present disclosure is not limited to the above exemplary embodiments. Variants of the above exemplary embodiments are also within the scope of the present disclosure.

[0089] For example, the present disclosure has been made by considering mainly the case of A-loT devices. However, the present disclosure can also be used for non-A-loT devices.

[0090] It should also be noted that there can be a coexistence in the wireless communication system between UEs 20 which apply the present disclosure and UEs which perform legacy contention resolution. For example, the present disclosure may apply e.g. only to A-loT devices whereas non-A-loT devices may perform legacy uplink transmission. Hence, the indication of the at least one first set of uplink resources and the at least one second set of uplink resources may be used only by A-loT devices.

Claims

Claims1. A method (40) for exchanging data in a wireless communication system, the method being implemented by a user equipment, UE (20), of the wireless communication system, wherein the UE comprises a communication unit (253) configured to exchange data with a radio access network, RAN, of the wireless communication system, wherein the method comprises:(540) receiving from the RAN an uplink transmission triggering signal used to trigger an uplink transmission by a plurality of UEs, wherein the uplink transmission triggering signal includes an indication of at least one first set of uplink resources and at least one second set of uplink resources, wherein the at least one second set of uplink resources is different from the at least one first set of uplink resources,(541) evaluating whether the UE has a UE identity known to the RAN, in response to the UE having a UE identity known to the RAN: (S42) using the at least one first set of uplink resources for performing an uplink transmission, in response to the UE not having a UE identity known to the RAN: (S43) using the at least one second set of uplink resources for performing the uplink transmission.

2. The method (40) according to claim 1 , wherein the at least one first set of uplink resources and the at least one second set of uplink resources correspond to random-access uplink resources.

3. The method (40) according to any one of the preceding claims, wherein the at least one first set of uplink resources corresponds to contention free uplink resources and the at least one second set of uplink resources corresponds to contention-based uplink resources.

4. The method (40) according to any one of the preceding claims, wherein the uplink transmission triggering signal includes an indication of a plurality of first sets of uplink resources and / or a plurality of second sets of uplink resources.

5. The method (40) according to claim 4, wherein the uplink transmission triggering signal includes an indication of a plurality of first sets of uplink resources together with a plurality of first set identifiers associated to different UEs having UE identities known to the RAN, and the method further comprises, in response to the UE having a UE identity known to the RAN, retrieving the first set identifier associated to said UE and selecting, among the plurality of first sets of uplink resources, the first set of uplink resources identified by the retrieved first set identifier for performing the uplink transmission.

6. The method (40) according to any one of the preceding claims, wherein the uplink transmission triggering signal is a paging message and / or a wake-up signal transmitted by the RAN that transitions the UE from a sleep mode to an active mode.

7. The method (40) according to any one of the preceding claims, wherein the UE comprises an energy harvesting unit (254) configured to convert ambient energy into electrical energy that is stored in an energy storage unit (255) of the UE.

8. A user equipment, UE (20), comprising at least one memory and at least one processor configured to carry out a method (40) according to any one of the preceding claims.

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, wherein the BS is configured to exchange data with a plurality of user equipment, UEs (20), wherein the method comprises (S50) transmitting to the plurality of UEs an uplink transmission triggering signal which comprises an indication of at least one first set of uplink resources and at least one second set of uplink resources to be used during an uplink transmission, wherein the at least one second set of uplink resources is different from the at least one first set of uplink resources, wherein the at least one first set of uplink resources is to be used by UEs having an UE identity known to the RAN and the at least one second set of uplink resources is to be used by UEs not having an UE identity known to the RAN.

10. The method (50) according to claim 9, wherein the at least one first set of uplink resources and the at least one second set of uplink resources correspond to random-access uplink resources.

11. The method (50) according to any one of claims 9 to 10, wherein the at least one first set of uplink resources corresponds to contention free uplink resources and the at least one second set of uplink resources corresponds to contention-based uplink resources.

12. The method (50) according to any one of claims 9 to 11, wherein the uplink transmission triggering signal includes an indication of a plurality of first sets of uplink resources and / or a plurality of second sets of uplink resources.

13. The method (50) according to claim 12, wherein the uplink transmission triggering signal includes an indication of a plurality of first sets of uplink resources together with a plurality of first set identifiers associated to different UEs having UE identities known to the RAN, to be used by the UEs having UE identities for selecting a first set of uplink resources among the plurality of first sets of uplink resources.

14. The method (50) according to any one of claims 9 to 13, wherein the uplink transmission triggering signal is a paging message and / or a wake-up signal that transitions the plurality of UEs from a sleep mode to an active mode.

15. The method (50) according to any one of claims 9 to 14, wherein each of theplurality of UEs comprises an energy harvesting unit (254) configured to convert ambient energy into electrical energy that is stored in an energy storage unit (255) of the UE.

16. A base station, BS (30), comprising at least one memory and at least one processor configured to carry out a method (50) according to any one of claims 9 to 15.

17. A wireless communication system comprising at least one base station (30) according to claim 16 and at least one user equipment (20) according to claim 8.

18. A computer program product (252, 302) comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method (40) according to any one of claims 1 to 7 or a method (50) according to any one of claims 9 to 15.

19. A computer-readable storage medium comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method (40) according to any one of claims 1 to 7 or a method (50) according to any one of claims 9 to 15.

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