Methods and devices for exchanging data with a wireless device having a low power operating mode

Abstract

The present disclosure relates to methods and devices for saving energy on a user equipment, UE (20), side of a wireless communication system, by enabling a low power wake-up signal received, LP-WUR (254), of a wireless device (25) of the UE to exchange data with a radio access network, RAN, of the wireless communication system.

Description

Methods and devices for exchanging data with a wireless device having a low power operating modeTechnical field

[0001] The present disclosure relates to wireless communication systems and relates more specifically to methods and devices for saving energy on a user equipment, UE, side of the wireless communication system.Background

[0002] To reduce energy consumption, extended discontinuous reception, eDRX, has been introduced in 3GPP (Third Generation Partnership Project) wireless communication systems. Basically, in eDRX, the UE periodically goes to sleep for an asleep duration during which a physical downlink control channel, PDCCH, is not monitored before waking up for an awake duration to monitor the PDCCH for possible downlink data. The amount of energy that can be saved depends on how long and how often the UE remains asleep. Of course, the longer the UE remains asleep, the greater the amount of energy saved. However, increasing the asleep duration comes with increased latency, which makes eDRX not suitable for latency-critical use cases.

[0003] To enhance energy savings without sacrificing latency in 5G or New Radio (NR) wireless communication systems, 3GPP is willing to define a new architecture for UEs (see e.g., the technical report TR 38.869).

[0004] Basically, current UEs need to periodically wake up once per eDRX cycle, which dominates the energy consumption in periods with no signaling or data traffic. If UEs were able to wake up only when they are triggered, e.g., paging, energy consumption could be dramatically reduced. As investigated by 3GPP, this is achieved by providing the UE with both a main radio, MR, unit, and a low power wake-up receiver, LP-WUR.

[0005] Basically, the MR unit corresponds to the 5G NR wireless communication unit, and the LP-WUR corresponds to a wireless communication unit that is used to monitor a wakeup signal with low power consumption. Once the wake-up signal is detected, the LP-WUR can trigger the MR unit which can transition from a low power state to an active state.

[0006] The active state corresponds to any state in which the MR unit can exchange data with a radio access network, RAN, of the wireless communication system without being triggered by the LP-WUR. Hence, a MR unit that is awake is in the active state. Also, a MR unit that is asleep but wakes-up periodically (e.g., eDRX) without being triggered by a LP- WUR is also in the active state.

[0007] The low power state corresponds to a state in which the MR unit cannot exchange data with the RAN without being triggered by the LP-WUR. For instance, the low power state corresponds to the MR unit being always asleep. However, since the MR unit doesnot have to wake-up periodically in the low power state, the MR unit may be even more deeply asleep than in current UEs and may even be turned off since the LP-WLIR can be used to turn the MR unit on.

[0008] By “low power” state, we mean that the mean power consumption of the MR unit in the low power state is lower than (and preferably significantly lower than, e.g., ten times or even a hundred times lower than) the mean power consumption of the MR unit in the active state.

[0009] By “low power” wake-up receiver, we mean that the LP-WLIR is used for receiving a wake-up signal while the MR unit is in the low power state. Of course, the monitoring of the wake-up signal should be done with a low power consumption, and the mean power consumption of the LP-WLIR should therefore be lower than (and preferably significantly lower than, e.g., ten times or even a hundred times lower than) the mean power consumption of the MR unit when it is awake.

[0010] Hence, the energy consumption is reduced by placing the MR unit in the low power state (e.g., turned off). The MR unit is not required to wake-up periodically and may wakeup only when triggered by the LP-WLIR. Since the LP-WLIR may monitor the wake-up signal continuously, or at least frequently, the MR unit can be awakened by the LP-WLIR at any time, thereby reducing latency compared to e.g., eDRX.

[0011] However, new use cases for such an architecture of the UE should be investigated to further reduce the energy consumption of the UE.Summary

[0012] 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 further reducing the energy consumption by enabling the UE to use, in some cases, its LP-WUR for data exchange with the RAN instead of using its MR unit.

[0013] For this purpose, the present disclosure proposes to evaluate whether the data to be exchanged with the RAN verifies a predetermined low power data exchange criterion. If the low power data exchange criterion is verified for the data to be exchanged, then the LP- WUR may be used to receive or transmit this data. For example, the low power data exchange criterion is verified when the volume of data to be exchanged is small and / or can be exchanged using a low data rate.

[0014] According to a first aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, the method being implemented by a wireless device of the wireless communication system, wherein the wireless device comprises a main radio, MR, unit, configured to exchange data with a radio access network, RAN, of the wireless communication system, and a low-power wake-up receiver, LP-WUR, configuredto detect a wake-up signal transmitted by the RAN and to trigger a transition of the MR unit from a very low power state to an active state in response to detecting a wake-up signal transmitted by the RAN, wherein the method comprises exchanging data with the RAN by using the LP-WLIR if a low-power data exchange criterion is verified for the data to be exchanged.

[0015] 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.

[0016] In some embodiments, the method according to the first aspect comprises using the LP-WLIR to receive downlink, DL, data transmitted by the RAN in response to receiving, from the RAN, an indication that the DL data to be transmitted verifies the low-power data exchange criterion.

[0017] In some embodiments of the method according to the first aspect, the indication that the DL data to be transmitted verifies the low-power data exchange criterion is included in the wake-up signal.

[0018] In some embodiments, the method according to the first aspect comprises: evaluating whether uplink, UL, data to be transmitted to the RAN verifies the low- power data exchange criterion, in response to the low-power data exchange criterion being verified for the UL data to be transmitted: transmitting the UL data by using the LP-WUR.

[0019] In some embodiments of the method according to the first aspect, the low-power data exchange criterion is verified if a volume of data to be exchanged is lower than a maximum data volume threshold and / or if a data rate required for exchanging the data is lower than a maximum data rate threshold.

[0020] In some embodiments of the method according to the first aspect, the low-power data exchange criterion is verified if the LP-WUR is determined to be within low power data exchange range of the RAN.

[0021] In some embodiments of the method according to the first aspect, the LP-WUR is determined to be within low power data exchange range of the RAN if an estimated reception level, representative of an expected reception level, by the LP-WUR, of radio signals transmitted by the RAN, is greater than a minimum reception level threshold.

[0022] In some embodiments, the method according to the first aspect comprises receiving the maximum data volume threshold and / or the maximum data rate threshold and / or the minimum reception level threshold from the RAN.

[0023] In some embodiments of the method according to the first aspect, data exchange by using the LP-WUR of the wireless device is carried out with the wireless device in the low power operating mode.

[0024] According to a second aspect, the present disclosure relates to a wireless device comprising at least one memory and at least one processor configured to carry out a method according to any one of the embodiments of the first aspect.

[0025] According to a third aspect, the present disclosure relates to a user equipment, UE, comprising a wireless device according to any one of the embodiments of the present disclosure.

[0026] According to a fourth aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, the method being implemented by a base station, BS, of a radio access network, RAN, of the wireless communication system, wherein the BS is configured to exchange data with a wireless device which comprises a main radio, MR, unit and a low-power wake-up receiver, LP-WLIR, wherein the LP-WLIR is configured to detect a wake-up signal transmitted by the BS and to trigger a transition of the MR unit from a very low power state to an active state in response to detecting a wake-up signal transmitted by the BS, wherein the method comprises exchanging data with the wireless device by using the LP-WLIR if a low-power data exchange criterion is verified for the data to be exchanged.

[0027] In some embodiments, the method according to the fourth aspect can further comprise one or more of the following optional features, considered either alone or in any technically possible combination.

[0028] In some embodiments, the method according to the fourth aspect comprises: evaluating whether downlink, DL, data to be transmitted to the wireless device verifies the low-power data exchange criterion, in response to the low-power data exchange criterion being verified for the DL data to be transmitted: transmitting to the wireless device an indication that the DL data to be transmitted verifies the low-power data exchange criterion and transmitting the DL data to the LP-WUR of the wireless device.

[0029] In some embodiments of the method according to the fourth aspect, the indication that the DL data to be transmitted verifies the low-power data exchange criterion is included in the wake-up signal.

[0030] In some embodiments of the method according to the fourth aspect, the low-power data exchange criterion is verified if a volume of data to be exchanged is lower than a maximum data volume threshold and / or if a data rate required for exchanging the data is lower than a maximum data rate threshold.

[0031] In some embodiments of the method according to the fourth aspect, the low-power data exchange criterion is verified if the LP-WUR is determined to be within low power data exchange range of the RAN.

[0032] In some embodiments of the method according to the fourth aspect, the LP-WUR isdetermined to be within low power data exchange range of the RAN if an estimated reception level, representative of an expected reception level, by the LP-WLIR, of radio signals transmitted by the BS, is greater than a minimum reception level threshold.

[0033] In some embodiments, the method according to the fourth aspect comprises transmitting the maximum data volume threshold and / or the maximum data rate threshold and / or the minimum reception level threshold to the wireless device.

[0034] According to a fifth aspect, the present disclosure relates to a base station, BS, comprising at least one memory and at least one processor configured to carry out a method according to any one of the embodiments of the fourth aspect.

[0035] According to a sixth aspect, the present disclosure relates to a wireless communication system comprising at least one base station according to any one of the embodiments of the present disclosure and at least one user equipment according to any one of the embodiments of the present disclosure.

[0036] According to a seventh aspect, the present disclosure relates to a computer program product comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method for exchanging data according to any one of the embodiments of the present disclosure. The computer program product can use any programming language, and can be in the form of source code, object code, or in any intermediate form between source code and object code, such as in a partially compiled form, or in any other desirable form.

[0037] According to an eighth aspect, the present disclosure relates to a (non-transitory) computer-readable storage medium comprising instructions which, when executed by at least one processor, configure said at least one processor to carry out a method for transmitting control messages according to any one of the embodiments of the present disclosure.Brief description of figures

[0038] 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 : a schematic representation of an example of wireless communication system comprising a BS and UEs,Figure 2: a schematic representation of an example of a wireless device, Figure 3: a schematic representation of an example of a BS,Figures 4 and 5: flow charts illustrating examples of methods for exchanging data implemented by a BS and a wireless device of a UE, respectively,Figures 6 and 7: flow charts illustrating other examples of methods for exchanging data implemented by a wireless device of a UE and a BS, respectively.

[0039] In these figures, references identical from one figure to another designate identicalor analogous elements. For reasons of clarity, the elements shown are not to scale, unless explicitly stated otherwise.Detailed description

[0040] The detailed description set forth below, with reference to the figures, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. For instance, although 3GPP terminology, from e.g., 5G NR, may be used in this disclosure to exemplify embodiments herein, this should not be seen as limiting the scope of the present disclosure.

[0041] 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.

[0042] 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 via radio signals. For example, the RAN may send data to the UEs (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 (uplink, UL), which data may be forwarded to the CN.

[0043] 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 (oreNB), 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.

[0044] In the example illustrated by figure 1 , two UEs 20-1 and 20-2 are represented. The UEs 20-1 and 20-2 are located in a coverage 31 (a.k.a. cell) of the BS 30. The coverage 31 of the BS 30 corresponds basically to the area in which UEs can decode a PDCCH transmitted by the BS 30.

[0045] 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. 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.

[0046] 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. 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.

[0047] 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.

[0048] As illustrated by figure 2, the wireless device 25 comprises also a main radio, MR, unit 253, and a low power wake-up signal receiver, LP-WUR, 254.

[0049] As discussed above, the MR unit 253 corresponds to a main wireless communication unit of the wireless device 25, used for exchanging data with BSs 30 of the RAN using radio signals. The MR 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 MR unit 253 corresponds to a 5G NR wireless communication unit.

[0050] The LP-WUR 254 corresponds to a secondary wireless communication unit of thewireless device 25, that is used to monitor a wake-up signal, transmitted by BSs 30 of the RAN, with low power consumption. The wake-up signal may take any form enabling it to be detected with low power consumption. Non-limitative examples for the wake-up signal and the LP-WLIR 254 are provided in the technical report TR 38.869. It should be noted that, in some examples, the wake-up signal can even be a specific 5G NR signal, for instance using a low-level modulation and coding scheme, MCS, in which case the LP-WLIR 254 can consist in the components of a 5G NR wireless communication unit strictly required to be able to detect such a specific 5G NR signal.

[0051] As discussed above, the purpose of the LP-WLIR 254 is mainly to monitor and detect a (DL) wake-up signal transmitted by the RAN of the wireless communication system. As such, the LP-WLIR 254 may be only unidirectional, i.e. , with only receiving capabilities (DL) and no transmitting capabilities (UL). However, in some examples, the LP-WLIR 254 may also have transmitting capabilities, such that it can also transmit (UL) data to the RAN.

[0052] The wireless device 25 is adapted to be operated in at least two operating modes which include a normal operating mode and a low power operating mode: in the normal operating mode, the MR unit 253 is in an active state, in the low power operating mode, the MR unit 253 is in a low power state and the LP-WUR 254 is configured to trigger a transition to the normal operating mode in response to detecting a wake-up signal transmitted by the RAN.

[0053] As discussed above, the active state corresponds to any state in which the MR unit253 can exchange data with the RAN without being triggered by the LP-WUR. Hence, a MR unit 253 that is awake is in the active state. Also, a MR unit 253 that is asleep but wakesup periodically (e.g., eDRX) without being triggered by a LP-WUR 254 is also in the active state.

[0054] The low power state corresponds to a state in which the MR unit 253 cannot exchange data with the RAN without being triggered by the LP-WUR 254. For instance, the low power state corresponds to the MR unit 253 being always asleep. However, since the MR unit 253 does not have to wake-up periodically in the low power state, thanks to the LP- WUR 254, the MR unit 253 may be ultra-deeply asleep and may even be turned off since the LP-WUR 254 can be used to turn the MR unit 253 on.

[0055] It should be noted that, in some examples, the LP-WUR 254 may also be configured to trigger the MR unit 253 when other conditions are verified. For example, the LP-WUR254 may be configured to trigger the MR unit 253 if a predetermined timer has expired without detecting a wake-up signal. Such a timer may be used to ensure that the wireless device 25 can return to the active state when e.g., the wireless device 25 has moved out of the coverage of the wake-up signal. Of course, the duration of this timer should be sufficiently high to ensure that the MR unit 253 can remain in the low power state over longperiods.

[0056] Figure 3 represents schematically an example of a BS 30 suitable to implement any method, discussed in the present disclosure, performed by the RAN.

[0057] 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.

[0058] 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 MR 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 corresponds to a 5G NR transceiver.

[0059] As illustrated by figure 3, the BS 30 comprises also a wake-up signal transmitter, WUT, 304, configured to transmit wake-up signals to UEs having a wireless device 25 which includes a LP-WUR 254. In the example illustrated by figure 3, the WUT 304 is represented as separate from the wireless communication unit 303. However, the WUT 304 may also be included in the wireless communication unit 303, e.g., if the wireless communication unit 303 is a 5G NR transceiver and if the wake-up signal is a specific 5G NR signal.

[0060] As discussed above for the LP-WUR 254, the purpose of the WUT 304, if separate from the wireless communication unit 30, is mainly to transmit a (DL) wake-up signal. As such, the WUT 304 may be only unidirectional, i.e. , with only transmitting capabilities (DL) and no receiving capabilities (UL). However, in some examples, the WUT 304 may also have receiving capabilities, such that it can also receive (UL) data from a LP-WUR 254 of a UE 20.

[0061] As illustrated by figure 3, the BS 30 may comprise also a network communication unit 305, 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.

[0062] As discussed above, the present disclosure aims at enabling, in some cases, the wireless device 25 to exchange data with a BS 30 of the RAN by using its LP-WUR 254instead of using its MR unit 253. Such data, other than the wake-up signal, may be DL data and / or UL data (provided that the LP-WLIR 254 has transmitting capabilities), depending on the scenarios. Basically, the present disclosure proposes that the LP-WLIR 254 is used to exchange data when the data to be exchanged verifies a predetermined low power data exchange criterion. By “low power” data exchange criterion, we simply mean that the data to be exchanged verifies a criterion enabling it to be exchanged by the LP-WLIR 254.

[0063] In some examples, the low power data exchange criterion depends on the data to be exchanged and is for instance verified if the volume of data to be exchanged is small and / or if the data can be exchanged with a low data rate. In other words, the LP-WLIR 254 can be used to exchange data with the RAN, instead of using the MR unit 253, if the volume of data to be exchanged is small and / or if the data can be exchanged with a low data rate. For example, the low power data exchange criterion is verified if the volume of data to be exchanged is lower than a predetermined maximum data volume threshold. Alternatively, or in combination thereof, the low power data exchange criterion may be considered verified if the data to be exchanged can be exchanged with a data rate that is lower than a predetermined maximum data rate threshold.

[0064] Alternatively, or preferably in combination thereof, the low power data exchange criterion depends on the propagation conditions between the RAN and the wireless device 25 and is for instance verified if these propagation conditions are sufficiently good to exchange data by using the LP-WLIR 254. In other words, the low power data exchange criterion may be considered verified if the LP-WLIR 254 is within low power data exchange range with a BS 30 of the RAN. For example, the LP-WLIR 254 is determined to be within low power data exchange range with the RAN if an estimated reception level, representative of an expected reception level, by the LP-WLIR 254, of radio signals transmitted by the BS 30, is greater than a predetermined minimum reception level threshold. For example, such a minimum reception level threshold may be also used for determining whether the wireless device 25 can be put in the low power operating mode. However, it is also possible to consider a first minimum reception level threshold for authorizing the wireless device 25 to be put in the low power operating mode and a second minimum reception level threshold, greater than the first minimum reception level threshold, for authorizing the wireless device 25 to use its LP-WLIR 254 to exchange data with a BS 30 of the RAN. In other words, exchanging data with the LP-WLIR 254 may require a greater reception level, at the LP- WUR 254, than for just monitoring and detecting a wake-up signal transmitted by the RAN.

[0065] Any threshold (e.g., maximum data volume threshold and / or maximum data rate threshold and / or minimum reception level threshold) possibly considered in the evaluation of the low power data exchange criterion may for example be preconfigured at the wireless device 25. For example, any such threshold may be predefined (e.g., specified by astandard), or it may be e.g., transmitted to the wireless device 25 by the BS 30 (e.g., included in system information broadcasted by the BS 30 or in a message dedicated to this wireless device 25, such as a radio resource control, RRC, message).

[0066] As discussed above, depending on the scenarios, the LP-WLIR 254 may be used to exchange data with the RAN, other than the wake-up signal, that may be DL data and / or UL data (provided that the LP-WLIR 254 has transmitting capabilities). If both DL and UL data exchange is possible with the LP-WLIR 254, then it is possible to use the same low power data exchange criterion for both DL and UL data, or to use different low power data exchange criteria for respectively DL data and UL data. For example, the thresholds possibly used may be different for DL and UL.

[0067] We now provide non-limitative examples of how the LP-WUR 254 can be used to exchange data with a BS 30 of the RAN.

[0068] Examples of DL low power data exchange

[0069] Figure 4 represents a diagram showing steps of an exemplary embodiment of a method 40 for exchanging data, which is implemented by a BS 30. Figure 5 represents a diagram showing corresponding steps of an exemplary embodiment of a method 50 for exchanging data, which is implemented by a wireless device 25 of a UE 20.

[0070] As illustrated by figure 4, the method 40 for exchanging data comprises a step S40 of evaluating whether DL data to be transmitted to the wireless device 25 verifies the low- power data exchange criterion. It is assumed that the DL data to be transmitted is received by the BS 30 while the wireless device 25 is in the low power operating mode.

[0071] In the DL, the low power data exchange criterion is for example verified, at the BS 30, if the wireless device 25 is in the low power operating mode (which may be triggered, at the wireless device 25, by a minimum reception level threshold) and if the volume of DL data to be transmitted is lower than a maximum DL data volume threshold.

[0072] If the DL low power data exchange criterion is not verified (e.g., the DL data volume is greater than the maximum DL data volume threshold) (reference S40b in figure 4), then the method 40 for exchanging data comprises a step S41 of transmitting the wake-up signal to the wireless device 25 and, once the wireless device 25 has detected the wake-up signal and has activated its MR unit 253, a step S42 of transmitting the DL data to the MR unit 253 of the wireless device 25.

[0073] In turn, if the DL low power data exchange criterion is verified (e.g., the DL data volume is lower than the maximum DL data volume threshold) (reference S40a in figure 4), then the method 40 for exchanging data comprises a step S43 of transmitting, to the wireless device 25, the wake-up signal and an indication that the DL data to be transmitted to the wireless device 25 verifies the DL low power data exchange criterion. Such an indication may be transmitted separately from the wake-up signal or, preferably, it may beincluded in the wake-up signal. For example, such an indication may consist in a bit which indicates whether the DL low power data exchange criterion is verified at the BS 30 (e.g., ‘0’ means that the DL low power data exchange criterion is verified and T means that the DL low power data exchange criterion is not verified). Once the wireless device 25 has detected the wake-up signal, the method 40 for exchanging data comprises a step S44 of transmitting, by the BS 30, the DL data to the LP-WUR 254 of the wireless device 25.

[0074] 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 wireless device 25 of a UE 20 when the BS 30 implements the method 40 for exchanging data illustrated by figure 4.

[0075] As illustrated by figure 5, the method 50 for exchanging data comprises a step S50 of receiving, by the wireless device 25 in the low power operating mode, a wake-up signal in relation with DL data to be transmitted from the BS 30.

[0076] If the DL data is to be received by the MR unit 253 of the wireless device 25 (e.g., if the wireless device 25 receives an indication that the DL low power data exchange criterion is not verified) (reference S50b in figure 5), then the method 50 for exchanging data comprises a step S51 of activating the MR unit 253 (i.e. , transition to the normal operating mode) for receiving the DL data.

[0077] In turn, if the DL data is to be received by the LP-WUR 254 of the wireless device 25 (e.g., if the wireless device 25 receives an indication that the DL low power data exchange criterion is verified) (reference S50a in figure 5), then the method 50 for exchanging data comprises a step S52 of receiving the DL data with the LP-WUR 254 (during which the wireless device 25 may remain in the low power operating mode).

[0078] In the non-limitative examples of figures 4 and 5, the DL low power data exchange criterion also includes an evaluation of whether the wireless device 25 is within low power data exchange range with the BS 30. In these examples, the wireless device 25 is considered within low power data exchange range if an estimated reception level, representative of an expected reception level, by the LP-WUR 254, of radio signals transmitted by the BS 30, is greater than a minimum reception level threshold. In the non- limitative examples of figures 4 and 5, the minimum reception level threshold is configured by the BS 30 and: the method 40 for exchanging data comprises a step S45 of transmitting, by the BS 30, the minimum reception level threshold to the wireless device 25, the method 50 for exchanging data comprises a step S53 of receiving, by the wireless device 25, the minimum reception level threshold from the BS 30.

[0079] The minimum reception level threshold may be included in any suitable signaling message. For example, the minimum reception level threshold is included in systeminformation broadcasted by the BS 30 or in a message dedicated to this wireless device 25 (e.g., in a RRC message).

[0080] Also, in the non-limitative examples of figures 4 and 5, the minimum reception level threshold is used for determining whether the wireless device 25 can be put in the low power operating mode. As illustrated by figure 5, the method 50 for exchanging data comprises a step S54 whereby the wireless device 25 goes to the low power operating mode, at least in response to the estimated reception level, representative of an expected reception level, by the LP-WLIR 254, of radio signals transmitted by the BS 30, being greater that the minimum reception level threshold. At the BS 30, the fact that the wireless device 25 is in the low power operating mode implies that the wireless device 25 is within low power data exchange range with the BS 30, such that the BS 30 needs only to evaluate the DL data volume to be transmitted to the wireless device 25.

[0081] Basically, the estimated reception level corresponds to any parameter that can be used to predict if the wireless device 25 will likely be able to decode radio signals transmitted by the BS 30 and received by the LP-WLIR 254. In practice, any measurement which includes a measurement of a pathloss between the BS 30 and the wireless device 25 can be considered representative of the expected reception level, by the LP-WLIR 254, of radio signals (e.g., a wake-up signal) transmitted by the BS 30, since the pathloss depends on the distance between the BS 30 and the LP-WLIR 254. Hence, the estimated reception level can for instance be determined by measuring any radio signal transmitted by the BS 30. For example, the estimated reception level may be determined by measuring a reference signal transmitted by the wireless communication unit 303 of the BS 30 (measured by the MR unit 253), or by the WUT 304 of the BS 30 (measured by the MR unit 253 or by the LP- WUR 254). It is also possible, in other examples, to determine the estimated reception level based on a measurement of a wake-up signal transmitted by the BS 30. For instance, the estimated reception level may be determined based on: the reception level measured by the LP-WLIR 254 of the wireless device 25 for a wake-up signal transmitted by the BS 30 to another wireless device, and / or the reception level measured by the LP-WLIR 254 of the wireless device 25 for a wake-up signal addressed to said wireless device 25, received during a previous period during which the wireless device 25 was in the low power operating mode.

[0082] For instance, the estimated reception level, determined based on the measurement of a reference signal transmitted by the BS 30, may be correspond to a reference signal receive power, RSRP, of the reference signal and / or to a reference signal receive quality, RSRQ, of the reference signal, as defined by the 3GPP specifications.

[0083] Examples of UL low power data exchange

[0084] Figure 6 represents a diagram showing steps of an exemplary embodiment of amethod 60 for exchanging data, which is implemented by a wireless device 25 of a UE 20. Figure 7 represents a diagram showing corresponding steps of an exemplary embodiment of a method 70 for exchanging data, which is implemented by a BS 30.

[0085] As illustrated by figure 6, the method 60 for exchanging data comprises a step S60 evaluating whether UL data to be transmitted by the wireless device 25 verifies the low- power data exchange criterion.

[0086] In the UL, the low power data exchange criterion is for example verified, at the wireless device 25, if the wireless device 25 is in the low power operating mode (which may be triggered, at the wireless device 25, by a minimum reception level threshold) and if the volume of UL data to be transmitted is lower than a maximum UL data volume threshold.

[0087] In the non-limitative example of figure 6, it is assumed that the evaluating step S60 is executed while the wireless device 25 is in the low power operating mode.

[0088] If the UL low power data exchange criterion is not verified (e.g., the UL data volume is greater than the maximum UL data volume threshold) (reference S60b in figure 6), then the method 60 for exchanging data comprises a step S61 of transmitting the UL data by using the MR unit 253. Since the wireless device 25 is assumed to be initially in the low power operating mode, the wireless device 25 is placed in the normal operating mode, by activating the MR unit 253, before transmitting the UL data.

[0089] In turn, if the UL low power data exchange criterion is verified (e.g., the UL data volume is lower than the maximum UL data volume threshold) (reference S60a in figure 6), then the method 60 for exchanging data comprises a step S62 of transmitting, to the BS 30, the UL data by using the LP-WUR 254 of the wireless device 25. The MR unit 253 may remain in the low power state.

[0090] It should be noted that, in other examples not represented in the figures, the UL low power data exchange criterion may not require the wireless device 25 to be in the low power operating mode. In such a case, the wireless device 25 may be in the normal operating mode when evaluating the UL low power data exchange criterion. If the UL low power data exchange criterion is not verified, then the wireless device 25 transmits the UL data by using the MR unit 253. If the UL low power data exchange criterion is verified, then the wireless device 25 transmits the UL data by using the LP-WUR 254. The UL low power data exchange criterion is for example verified if the volume of UL data to be exchanged is lower than a maximum UL data volume threshold. The UL low power data exchange criterion, to be verified, may further require that an estimated reception level (representative of an expected reception level, by the LP-WUR 254, of radio signals transmitted by the BS 30) is greater than a minimum reception level. In the latter case, the wireless device 25, if initially in the normal operating mode, may optionally be placed in the low power operating mode in response to the UL low power data exchange criterion being verified.

[0091] As discussed above, figure 7 represents a diagram showing corresponding steps of an exemplary embodiment of a method 70 for exchanging data, which may be implemented by a BS 30 when the wireless device 25 of a UE 20 implements the method 60 for exchanging data illustrated by figure 6.

[0092] As illustrated by figure 7, the method 70 for exchanging data comprises basically a step S70 of receiving, by the BS 30, the UL data transmitted by the wireless device 25. The UL data may be received by the WUT 304 or by the wireless communication unit 303.

[0093] In the non-limitative examples of figures 6 and 7, the UL low power data exchange criterion also includes an evaluation of whether the wireless device 25 is within low power data exchange range with the BS 30. In these examples, the wireless device 25 is considered within low power data exchange range if an estimated reception level, representative of an expected reception level, by the LP-WUR 254, of radio signals transmitted by the BS 30, is greater than a minimum reception level threshold. Also, in the non-limitative examples of figures 6 and 7, the minimum reception level threshold is used for determining whether the wireless device 25 can be put in the low power operating mode. As illustrated by figure 6, the method 60 for exchanging data comprises a step S64 whereby the wireless device 25 goes to the low power operating mode, at least in response to an estimated reception level, representative of an expected reception level, by the LP-WUR 254, of radio signals transmitted by the BS 30, being greater that the minimum reception level threshold. During the evaluating step S60, the fact the wireless device 25 is in the low power operating mode, before receiving UL data to be transmitted to the BS 30, implies that the wireless device 25 is within low power data exchange range with the BS 30, such that the wireless device 25 needs only to evaluate the UL data volume to be transmitted to the BS 30. It should be noted that, if a different minimum reception level threshold is considered in the UL low power data exchange threshold (for example a second minimum reception level threshold greater than a first minimum reception level threshold used for authorizing the wireless device 25 to go into the low power operating mode), then it can be evaluated during step S60.

[0094] In the non-limitative examples of figures 6 and 7, it is further considered in a non- limitative manner that the one or more thresholds (e.g., maximum UL data volume threshold and / or minimum reception level threshold) are configured by the BS 30 and: the method 70 for exchanging data comprises a step S71 of transmitting, by the BS 30, the one or more thresholds to the wireless device 25, the method 60 for exchanging data comprises a step S63 of receiving, by the wireless device 25, the one or more thresholds from the BS 30.

[0095] These one or more thresholds may be included in any suitable signaling message(s). For example, the one or more thresholds are included in system information broadcastedby the BS 30 and / or in a message(s) dedicated to this wireless device 25.

Claims

Claims1. A method (50, 60) for exchanging data in a wireless communication system, the method being implemented by a wireless device (25) of the wireless communication system, wherein the wireless device comprises a main radio, MR, unit (253), configured to exchange data with a radio access network, RAN, of the wireless communication system, and a low- power wake-up receiver, LP-WLIR (254), configured to detect a wake-up signal transmitted by the RAN and to trigger a transition of the MR unit from a very low power state to an active state in response to detecting a wake-up signal transmitted by the RAN, wherein the method comprises exchanging data with the RAN by using the LP-WLIR if a low-power data exchange criterion is verified for the data to be exchanged.

2. The method (50) according to claim 1 , comprising using the LP-WLIR to receive downlink, DL, data transmitted by the RAN in response to receiving, from the RAN, an indication that the DL data to be transmitted verifies the low-power data exchange criterion.

3. The method (50) according to claim 2, wherein the indication that the DL data to be transmitted verifies the low-power data exchange criterion is included in the wake-up signal.

4. The method (60) according to any one of the preceding claims, comprising:(S60) evaluating whether uplink, UL, data to be transmitted to the RAN verifies the low-power data exchange criterion, in response to the low-power data exchange criterion being verified for the UL data to be transmitted: (S62) transmitting the UL data by using the LP-WUR.

5. The method (50, 60) according to any of the preceding claims, wherein the low- power data exchange criterion is verified if a volume of data to be exchanged is lower than a maximum data volume threshold and / or if a data rate required for exchanging the data is lower than a maximum data rate threshold.

6. The method (50,60) according to any of the preceding claims, wherein the low- power data exchange criterion is verified if the LP-WUR is determined to be within range of the RAN.

7. The method (50, 60) according to claim 6, wherein the LP-WUR is determined to be within low power data exchange range of the RAN if an estimated reception level, representative of an expected reception level, by the LP-WUR, of radio signals transmitted by the RAN, is greater than a minimum reception level threshold.

8. The method (50, 60) according to claim 5 or claim 7, comprising receiving the maximum data volume threshold and / or the maximum data rate threshold and / or the minimum reception level threshold from the RAN.

9. A wireless device (25) comprising at least one memory (251) and at least one processor (250) configured to carry out a method according to any one of the precedingclaims.

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

11. A method (40, 70) for exchanging data in a wireless communication system, the method being implemented by a base station, BS (30), of a radio access network, RAN, of the wireless communication system, wherein the BS is configured to exchange data with a wireless device (25) which comprises a main radio, MR, unit (253) and a low-power wakeup receiver, LP-WLIR (254), wherein the LP-WLIR is configured to detect a wake-up signal transmitted by the BS and to trigger a transition of the MR unit from a very low power state to an active state in response to detecting a wake-up signal transmitted by the BS, wherein the method comprises exchanging data with the wireless device by using the LP-WLIR if a low-power data exchange criterion is verified for the data to be exchanged.

12. The method (40) according to claim 11 , comprising:(S40) evaluating whether downlink, DL, data to be transmitted to the wireless device verifies the low-power data exchange criterion, in response to the low-power data exchange criterion being verified for the DL data to be transmitted: (S43) transmitting to the wireless device an indication that the DL data to be transmitted verifies the low-power data exchange criterion and (S44) transmitting the DL data to the LP-WUR of the wireless device.

13. The method (40) according to claim 12, wherein the indication that the DL data to be transmitted verifies the low-power data exchange criterion is included in the wake-up signal.

14. The method (40, 70) according to any of claims 11 to 13, wherein the low-power data exchange criterion is verified if a volume of data to be exchanged is lower than a maximum data volume threshold and / or if a data rate required for exchanging the data is lower than a maximum data rate threshold.

15. The method (40, 70) according to any of claims 11 to 14, wherein the low-power data exchange criterion is verified if the LP-WUR is determined to be within low power data exchange range of the RAN.

16. The method (40, 70) according to claim 15, wherein the LP-WUR is determined to be within low power data exchange range of the RAN if an estimated reception level, representative of an expected reception level, by the LP-WUR, of radio signals transmitted by the BS, is greater than a minimum reception level threshold.

17. The method (40, 70) according to claim 14 or claim 16, comprising transmitting the maximum data volume threshold and / or the maximum data rate threshold and / or the minimum reception level threshold to the wireless device.

18. A base station, BS (30), comprising at least one memory (301) and at least one processor (300) configured to carry out a method according to any one of claims 11 to 17.

19. A wireless communication system comprising at least one base station (30) according to claim 18 and at least one user equipment (20) according to claim 10.

20. 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 according to any one of claims 1 to 8 or a method according to any one of claims 11 to 17.

21. 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 according to any one of claims 1 to 8 or a method according to any one of claims 11 to 17.

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