Method and device for implementing energy saving on a UE that performs discontinuous reception

Abstract

The present disclosure relates to methods and devices for enabling a user equipment (UE - user equipment) (20) having a low power wake-up signal receiver (LP-WUR) (254) to reduce its energy consumption during an active discontinuous reception (DRX - discontinuous reception) period of a DRX cycle.

Description

Technical field

[0001] The present disclosure relates to wireless communication systems and in particular to methods and devices for saving energy on a user equipment (UE) side of the wireless communication system. background

[0002] To reduce energy consumption, discontinuous reception (DRX) was introduced in 3GPP (Third Generation Partnership Project) wireless communication systems. Essentially, with DRX, the user entity (UE) periodically enters a sleep state for a period of time during which the physical downlink control channel (PDCCH) is not monitored. It then wakes up for a period of time to monitor the PDCCH for any downlink control data. The amount of energy that can be saved depends on how long and how frequently the UE remains in sleep mode. Naturally, the longer the UE remains in sleep mode, the greater the amount of energy saved.

[0003] In order to improve energy savings without increasing latency in wireless 5G or New Radio (NR) communication systems, 3GPP is ready to define a new architecture for UEs (see, for example, technical report TR 38.869).

[0004] Essentially, current UEs must periodically wake up once per DRX cycle, which dominates power consumption during periods without signaling or data traffic. If UEs were able to wake up only when triggered, for example, by a radio call, power consumption could be drastically reduced. As investigated by 3GPP, this is achieved by equipping the UE with both a main radio (MR) unit and a low-power wake-up receiver (LT-WUR).

[0005] Essentially, the MR unit corresponds to the 5G NR unit for wireless communication, and the LT-WUR corresponds to a wireless communication unit used to monitor for a wake-up signal at low power consumption. Once the wake-up signal is detected, the LT-WUR can trigger the MR unit, which can then transition from a low-power to an active state.

[0006] The active state corresponds to a state in which the MR unit can exchange data with a radio access network (RAN) of the wireless communication system. The power-saving state corresponds to any state in which the MR unit cannot exchange data with the RAN.

[0007] By "energy-saving" state, the authors mean that the average power consumption of the MR unit in energy-saving state is lower (and preferably significantly lower, e.g. ten times or even one hundred times lower) than the average power consumption of the MR unit in active state.

[0008] By "receiver for waking from 'power-saving' mode," the authors mean that the LP-WUR is used to receive a wake-up signal while the MR unit is in a power-saving state. Naturally, monitoring the wake-up signal should be performed at low power consumption, and therefore the average power consumption of the LP-WUR should be lower (and preferably significantly lower, e.g., ten times or even one hundred times lower) than the average power consumption of the MR unit when it is active.

[0009] Thus, energy consumption is reduced by putting the MRI unit into a power-saving state (e.g., switching it off). It is not necessary for the MRI unit to wake up periodically; it only needs to wake up when triggered by the LP-WUR. Since the LP-WUR can continuously or at least frequently monitor the wake-up signal, the MRI unit can potentially be woken up by the LP-WUR at any time, further enabling low latency.

[0010] For example, the LP-WUR can be used when the UE is performing DRX. As discussed above, DRX is based on a DRX cycle, which includes an active DRX period, during which the UE must wake up for the wake period, and an inactive DRX period, during which the UE enters sleep mode for the sleep period. Based on the DRX cycle, it is only possible to use the LP-WUR to wake the UE for the next active DRX period if a wake-up signal is detected during the inactive DRX period. If no wake-up signal is received during the inactive DRX period, then the UE can skip the next active DRX period, and the MR unit can remain in a low-power state during the next active DRX period (without monitoring the PDCCH).

[0011] Therefore, the LP-WUR can only be used to wake the UE for an active DRX period if the RAN intends to transmit control data to the UE via the PDCCH during that active DRX period. However, the UE must remain awake for the entire wake-up period of the active DRX period, as the UE does not know in advance when the control data will be transmitted by the RAN during that period.

[0012] Therefore, there is a need for a further reduction in energy consumption. Brief description

[0013] The present disclosure aims to improve the situation. In particular, the present disclosure aims to overcome at least some of the limitations of the prior art discussed above. Specifically, the present disclosure aims to propose a solution for reducing the duration that the MR unit must remain in the active state within an active DRX period of a DRX cycle.

[0014] According to a first aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, wherein the method is implemented by a wireless device of the wireless communication system, the wireless device comprising a 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) configured to monitor for a wake-up signal transmitted by the RAN and, in response to the detection of a wake-up signal, to trigger a transition of the MR unit to an active state, wherein the wireless device is configured with a discontinuous reception (DRX) cycle, the DRX cycle comprising an active DRX period,during which the wireless device can receive control data from the RAN via a physical downlink control channel (PDCCH), and an inactive DRX period during which the wireless device does not perform PDCCH monitoring, wherein the active DRX period comprises an inactive sub-period followed by an active sub-period, and wherein the method, in response to the detection by the LP-WUR of a wake-up signal during an inactive DRX period, during the following active DRX period, comprises the following: - Monitoring for a wake-up signal by the LP-WUR during the inactive sub-period, with the MR unit in a power-saving state, - in response to the detection of a wake-up signal during the inactive period: triggering a transition of the MR unit to the active state and performing PDCCH monitoring during the active period.

[0015] In some embodiments, the method according to the first aspect may further comprise one or more of the following optional features, which may be considered either alone or in any technically possible combination.

[0016] In some embodiments of the method according to the first aspect, the MR unit is kept in a power-saving state during the active part-time in response to the failure to detect a wake-up signal during the inactive part-time.

[0017] In some embodiments of the method according to the first aspect, the LP-WUR does not monitor for a wake-up signal during the active part-time in response to the failure to detect a wake-up signal during the inactive part-time.

[0018] In some embodiments, the method according to the first aspect includes receiving a configuration for an active DRX period that defines the inactive sub-period and the active sub-period within the active DRX period.

[0019] In some embodiments of the method according to the first aspect, the configuration for an active DRX period is received in system information transmitted through the RAN, and / or the configuration for an active DRX period is received in a radio resource control (RRC) reconfiguration message transmitted through the RAN.

[0020] In some embodiments of the method according to the first aspect, if no wake-up signal is detected during an inactive DRX period, the wireless device does not perform PDCCH monitoring during the following active DRX period.

[0021] In some embodiments of the method according to the first aspect, the active DRX period comprises a plurality of active sub-periods and / or the active DRX period comprises a plurality of inactive sub-periods.

[0022] In some embodiments of the method according to the first aspect, the active DRX period begins with an active partial period.

[0023] In some embodiments of the method according to the first aspect, the MR unit is kept in a power-saving state during the inactive DRX period, which is different from the power-saving state used during the inactive part of the active DRX period.

[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 perform a method according to any embodiment 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 embodiment 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, wherein the method is implemented by a base station (BS) of a radio access network (RAN) of the wireless communication system, the BS being configured to exchange data with a wireless device, the wireless device comprising a main radio (MR) unit and a low power wake-up receiver (LP-WUR), the LP-WUR being configured to detect a wake-up signal transmitted by the BS and, in response to the detection of a wake-up signal transmitted by the BS, triggering a transition of the MR unit to an active state, the BS being configured with a discontinuous reception (DRX) cycle, the DRX cycle comprising an active DRX period,during which the BS can transmit control data to the wireless device via a physical downlink control channel (PDCCH), and an inactive DRX period during which the BS does not transmit control data to the wireless device via the PDCCH, wherein the active DRX period includes at least one inactive sub-period and at least one active sub-period, and wherein the BS is configured to transmit control data to the wireless device via the PDCCH only during the at least one active sub-period.

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

[0028] In some embodiments, the method according to the fourth aspect, in response to determining that control data is to be transmitted in an active sub-period following an inactive sub-period of the active DRX period, includes: transmitting a wake-up signal to the wireless device in that inactive sub-period.

[0029] In some embodiments, the method according to the fourth aspect, in response to determining that control data should be transmitted during an active DRX period, includes: transmitting a wake-up signal to the wireless device during the inactive DRX period that follows this active DRX period.

[0030] In some embodiments, the method according to the fourth aspect includes transmitting a configuration for an active DRX period to the wireless device, wherein the configuration for an active DRX period defines the at least one inactive sub-period and the at least one active sub-period within the active DRX period.

[0031] In some embodiments of the method according to the fourth aspect, the configuration for an active DRX period is transmitted in system information sent through the RAN and / or the configuration for an active DRX period is transmitted in a radio resource control (RRC) reconfiguration message that is transmitted to the wireless device.

[0032] In some embodiments of the method according to the fourth aspect, the active DRX period begins with an active partial period.

[0033] According to a fifth aspect, the present disclosure relates to a base station (BS) comprising at least one memory and at least one processor configured to perform a method according to any embodiment of the fourth aspect.

[0034] According to a sixth aspect, the present disclosure relates to a wireless communication system comprising at least one base station according to any embodiment of the present disclosure and at least one user device according to any embodiment of the present disclosure.

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

[0036] 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 the at least one processor to perform a method for transmitting control messages according to any embodiment of the present disclosure. Brief description of the drawings

[0037] The invention will be better understood by reading the following description, which is given as an example that is in no way limiting, and is made with reference to the figures that show the following: - Fig. 1: A schematic representation of an example of a wireless communication system comprising a BS and UEs, - Fig. 2: a schematic representation of an example of a wireless device, - Fig. 3: a schematic representation of an example of a BS, - Fig. 4: Schematic representations of examples for different configurations of an active DRX period, - Fig. 5: Schematic diagrams illustrating the operation of a wireless device during a DRX cycle, - Fig. 6 and Fig. 7: Flowcharts illustrating examples of data exchange procedures implemented by a BS or a wireless device of an UE.

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

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

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

[0041] Fig. Figure 1 schematically represents an example of a wireless communication system, which could be, for example, a 5G NR wireless communication system. In particular, it represents Fig. Figure 1 represents a RAN of the wireless communication system used to exchange data with UEs 20 via radio signals. The RAN can, for example, send data to the UEs 20 (DL - downlink), such as data received from a core network (CN - core network, not shown in the figures). The RAN can also receive data from the UEs 20 (UL - uplink), and this data can be forwarded to the CN.

[0042] In the through Fig. In the illustrated example 1, the RAN includes one base station (BS) 30. Naturally, the RAN can include more than one BS 30 to extend the coverage area of ​​the wireless communication system. Each of these BSs can be referred to as an NB, eNodeB (or eNB), gNodeB (or gNB in ​​the case of a 5G NR wireless communication system), an access point, or the like, depending on the implemented wireless communication standard(s).

[0043] In the through Fig. In the illustrated example 1, two UEs 20 are shown. The UEs 20 are located in a coverage area 31 of the BS 30. The coverage area 31 of the BS 30 corresponds, for example, to the area in which UEs can decode a PDCCH transmitted by the BS 30.

[0044] Fig. Figure 2 schematically represents an example of a wireless device 25 suitable for implementing any method discussed in the present disclosure and carried out on a UE 20. Essentially, the wireless device 25 corresponds to a device that provides wireless connectivity to the RAN of the wireless communication system and can be used to exchange data with the RAN.

[0045] Such a wireless device 25 can be implemented in a UE 20, as described by Fig. 2 illustrated, may be included. The UE 20 can be, for example, a mobile phone, a wireless modem, a wireless communication device, a handheld device, a laptop computer, or the like. The UE 20 can also be an Internet of Things (IoT) device, such as a wireless camera, a smart sensor, smart glasses, a (manned or unmanned) vehicle, a global positioning system device, etc., or any other device capable of running applications that require data to be exchanged with remote receivers via the wireless device 25.

[0046] As through Fig. As illustrated in Figure 2, the wireless device 25 comprises one or more processors 250 and one or more memories 251. The one or more processors 250 may, for example, include a central processing unit (CPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), etc. The one or more memories 251 may include any type of computer-readable volatile and non-volatile memory (magnetic disk, solid-state storage, optical media, electronic storage, etc.).The one or more memory locations 251 can store a computer program product 252 in the form of a set of program-coded instructions to be executed by the one or more processors 250 to implement all or part of the steps of a method for exchanging data, which is carried out on the side of a UE according to any embodiment disclosed herein.

[0047] As through Fig. As illustrated in Figure 2, the wireless device 25 also includes a main radio (MR) unit 253 and a low power wake-up signal receiver (LP-WUR) 254.

[0048] As discussed above, the MR unit 253 corresponds to a main wireless communication unit of the wireless device 25, which is used to exchange data with BSs 30 of the RAN using radio signals. The MR unit 253 can implement one or more wireless communication protocols and can, for example, be a 3G, 4G, 5G, NR, WiFi, WiMax, etc. transceiver or the like. In preferred embodiments, the MR unit 253 corresponds to a 5G NR wireless communication unit.

[0049] The LP-WUR 254 corresponds to a secondary wireless communication unit of the wireless device 25, used to monitor a wake-up signal transmitted by BSs 30 of the RAN at low power consumption. The wake-up signal can take any form that allows it to be detected at low power consumption. Non-restrictive examples of the wake-up signal and the LP-WUR 254 are provided in Technical Report TR 38.869. It is noted that in some examples, the wake-up signal may even be a specific 5G-NR signal using, for example, a low-level modulation and coding scheme (MCS), in which case the LP-WUR 254 may consist of the components of a 5G-NR wireless communication unit that are expressly expected to be capable of detecting such a specific 5G-NR signal.

[0050] As discussed above, the primary purpose of the LP-WUR 254 is to monitor and detect a wake-up (DL) signal transmitted through the RAN of the wireless communication system. Therefore, the LP-WUR 254 can only be unidirectional, meaning it has receive capabilities (DL) only and no transmit capabilities (UL). However, in some examples, the LP-WUR 254 may also possess transmit capabilities, allowing it to transmit data to the RAN (UL).

[0051] The wireless device 25 is designed to operate in at least two operating modes, which include a normal operating mode and an energy-saving operating mode: - In normal operating mode, the MR unit 253 is in an active state, - In energy-saving operating mode, the MR unit 253 is in an energy-saving state and the LP-WUR 254 is configured to trigger a transition to normal operating mode in response to the detection of a wake-up signal transmitted through the RAN.

[0052] As discussed above, the active state corresponds to any state in which the MR unit 253 can exchange data with the RAN without being triggered by the LP-WUR.

[0053] The power-saving state corresponds to a state in which the MR unit 253 cannot exchange data with the RAN unless triggered by the LP-WUR 254. For example, the power-saving state corresponds to the state in which the MR unit 253 is always in sleep mode. However, since the MR unit 253 does not need to wake up periodically in the power-saving state, it can be in an extremely deep sleep state thanks to the LP-WUR 254 and can even be switched off, as the LP-WUR 254 can be used to switch the MR unit 253 on. It is also noted that it is possible to consider different power-saving states for the MR unit 253, each with a different average power consumption.For example, it is possible to consider a very low energy consumption state, which has the lowest average energy consumption, as well as one or more intermediate energy-saving states, which have an average energy consumption that is higher than the average energy consumption of the very low energy consumption state. For example, the very low energy consumption state could correspond to the state in which the MR unit 253 is switched off, and an intermediate energy-saving state could correspond to the state in which the MR unit 253 is in a sleep state without being switched off.

[0054] It is noted that in some examples, the LP-WUR 254 can also be configured to trigger the MR unit 253 when other conditions are verified. For example, the LP-WUR 254 can be configured to trigger the MR unit 253 when a predetermined timer expires without detecting a wake-up signal. Such a timer can be used to ensure that the wireless device 25 can return to the active state if, for example, the wireless device 25 has moved out of the wake-up signal's coverage area. Naturally, the duration of this timer should be sufficiently long to ensure that the MR unit 253 can remain in a low-power state for extended periods.

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

[0056] As through Fig. As illustrated in Figure 3, the BS 30 comprises one or more processors 300 and one or more memories 301. The one or more processors 300 may, for example, include a CPU, a DSP, an FPGA, an ASIC, etc. The one or more memories 301 may include any type of computer-readable volatile and non-volatile memory (magnetic disk, solid-state storage, optical media, electronic storage, etc.). The one or more memories 301 may store a computer program product 302 in the form of a set of program-coded instructions to be executed by the one or more processors 300 to implement all or part of the steps of a data-exchange method performed on the side of the RAN according to any embodiment disclosed herein.

[0057] As through Fig. As illustrated in Figure 3, the BS 30 also includes a wireless communication unit 303 configured to exchange data with UEs 20 using radio signals, and in particular with MR units 253 of wireless devices 25 contained in these UEs 20. The wireless communication unit 303 can, for example, be a 3G, 4G, 5G, NR, WiFi, WiMax, etc. transceiver or the like. In preferred embodiments, the wireless communication unit 303 of the BS 30 corresponds to a 5G NR transceiver.

[0058] As through Fig. As illustrated in Figure 3, the BS 30 also includes a wake-up signal transmitter (WUT) 304, which is configured to transmit wake-up signals to UEs that have a wireless device 25 containing an LP-WUR 254. In the Fig. In the illustrated example 3, the WUT 304 is shown as separate from the wireless communication unit 303. However, the WUT 304 can also be contained within the wireless communication unit 303, for example, if the wireless communication unit 303 is a 5G-NR transceiver and if the wake-up signal is a specific 5G-NR signal.

[0059] As discussed above for the LP-WUR 254, the primary purpose of the WUT 304, when separate from the Wireless Communication Unit 30, is to transmit a (DL) wake-up signal. Therefore, the WUT 304 can only be unidirectional, meaning it has only transmit capabilities (DL) and no receive capabilities (UL). However, in some examples, the WUT 304 may also have receive capabilities, allowing it to receive (UL) data from an LP-WUR 254 of a UE 20.

[0060] As through Fig. As illustrated in Figure 3, the BS 30 can also include a Network Communication Unit 305 configured to exchange data with other RAN base stations and / or with the CN. The Network Communication Unit 305 can support one or more suitable communication protocols, which may be wired (including fiber optic) and / or wireless.

[0061] As discussed above, the present disclosure aims to further reduce energy consumption when discontinuous reception (DRX) is performed. It should be noted that DRX also includes extended DRX (eDRX) as defined by 3GPP. In DRX mode, the wireless device 25 operates according to a DRX cycle comprising the following: - an inactive DRX period during which the wireless device 25 does not perform PDCCH monitoring, and - an active DRX period during which the wireless device can receive 25 control data points from the RAN via the PDCCH.

[0062] To reduce the need to keep the MR unit 253 in an active state during the active DRX period, it is proposed to divide the active DRX period into a plurality of sub-periods, which include the following: - one or more inactive partial periods during which the RAN cannot transmit control data via the PDCCH to the wireless device 25, and - one or more active partial periods during which the RAN can transmit control data via the PDCCH to the wireless device 25.

[0063] Since no control data can be received via the PDCCH during an inactive sub-period of the active DRX period, the MR unit 253 of the wireless device 25 can be placed into a power-saving state during each inactive sub-period of the active DRX period, so that the MR unit 253 no longer needs to remain in the active state for the entire duration of the active DRX period. Also, and as discussed below, if the active DRX period contains an active sub-period that follows an inactive sub-period, the RAN can use this inactive sub-period to indicate whether it intends to send control data via the PDCCH during the following active sub-period. For example, such an indication can be sent as a wake-up signal to be detected by the LP-WUR 254 of the wireless device 25.Thus, if a wake-up signal is detected during an inactive sub-period of the active DRX period, the MR unit 253 can enter the active state for the following active sub-period of the active DRX period. Conversely, if no wake-up signal is detected during an inactive sub-period, the MR unit 253 can remain in a power-saving state during the following active sub-period. Similarly, in some cases, if the LP-WUR 254 does not detect a wake-up signal during an inactive sub-period of the active DRX period, it can also enter a power-saving state (e.g., be switched off) for the duration of the following active sub-period of the active DRX period to further reduce energy consumption during the active DRX period. In some examples, the LP-WUR 254 can also be put into a power-saving state during all active sub-periods of the active DRX period (e.g.be switched off).

[0064] As discussed above, the active DRX period can comprise one or more active sub-periods and one or more inactive sub-periods, arranged such that the active DRX period consists of an alternation of one or more active sub-periods and one or more inactive sub-periods. In other words, no active sub-period can immediately follow or precede another active sub-period, and no inactive sub-period can immediately follow or precede another inactive sub-period. Preferably, an inactive sub-period is always followed by an active sub-period in order to be able to indicate to the wireless device 25 whether its MR unit 253 needs to be put into the active state for this subsequent active sub-period.

[0065] Fig. Figure 4 schematically illustrates various examples of configurations for an active DRX period.

[0066] In the section defined by part a) of Fig. In the 4 illustrated example, the active DRX period comprises a single inactive sub-period followed by a single active sub-period.

[0067] In the section by part b) of Fig. In the illustrated example 4, the active DRX period comprises three sub-periods. Specifically, the active DRX period begins with a first active sub-period, followed by an inactive sub-period, followed by a second active sub-period. In such a case, if a wake-up signal is detected during the preceding inactive DRX period, the MR unit 253 enters the active state for the duration of the first active sub-period to perform PDCCH monitoring. No PDCCH monitoring is performed during the inactive sub-period, and the MR unit 253 may enter a power-saving state. The LP-WUR 254 monitors for a wake-up signal during the inactive sub-period. If a wake-up signal is detected, the MR unit 253 enters the active state for the duration of the second active sub-period to perform PDCCH monitoring.If no wake-up signal is detected, the MR unit 253 can remain in a power-saving state for the duration of the second active period. The LP-WUR 254 does not need to monitor for a wake-up signal during the second active period, so it can be placed in a power-saving state in some examples.

[0068] In the section by part c) of Fig. In the illustrated example 4, the active DRX period comprises four sub-periods. Specifically, the active DRX period begins with a first inactive sub-period, followed by a first active sub-period, followed by a second inactive sub-period, followed by a second active sub-period.

[0069] In the section d) of Fig. In the illustrated example 4, the active DRX period comprises five sub-periods. Specifically, the active DRX period begins with a first active sub-period, followed by a first inactive sub-period, followed by a second active sub-period, followed by a second inactive sub-period, followed by a third active sub-period.

[0070] In some examples, it is possible to consider an identical duration for all inactive sub-periods and for all active sub-periods. However, it is also possible to consider a duration for the inactive sub-periods that differs from the duration of the active sub-periods. Similarly, the inactive sub-periods can all have the same duration, or the duration can vary from one inactive sub-period to another. Likewise, the active sub-periods can all have the same duration, or the duration can vary from one active sub-period to another.

[0071] Other configurations of an active DRX period may be considered, which, compared to those in Fig. The four examples provided include, for instance, additional active sub-periods and / or additional inactive sub-periods. Choosing a specific configuration of an active DRX period represents a specific, but not limiting, embodiment of the present disclosure.

[0072] In some examples, the configuration of an active DRX period may be predefined. In other examples, the configuration of an active DRX period may be determined by the wireless device 25 or by the RAN. In the latter case, the configuration of an active DRX period to be used by the wireless device 25 is received, for example, by the wireless device 25 in system information transmitted by a BS 30 of the RAN and / or in a radio resource control (RRC) reconfiguration message transmitted by a BS 30 of the RAN. Of course, other control messages may be used by the RAN to transmit an active DRX period configuration to the wireless device 25.In some cases, the configuration of an active DRX period can be transferred along with a configuration of a DRX cycle, which defines the active DRX period and the inactive DRX period in the DRX cycle.

[0073] Fig. Figure 5 schematically presents non-restrictive examples of how the wireless device 25 can reduce its energy consumption by assuming, in a non-restrictive manner, the configuration of an active DRX period as described in part d) of Fig. 4 is shown.

[0074] In the through Fig. In the 5 illustrated example, the LP-WUR 254 performs monitoring for a wake-up signal during the inactive DRX period of the DRX cycle, while the MR unit 253 is in a power-saving state, for example, in the very low energy consumption state discussed above.

[0075] In part a) of Fig. 5. If the LP-WUR 254 does not detect a wake-up signal, no PDCCH monitoring is performed during the following active DRX period. The MR unit 253 can therefore remain in a power-saving state for the entire active DRX period, thus reducing energy consumption compared to performing PDCCH monitoring during each active DRX period. Likewise, the LP-WUR 254 can, in some examples and as described in a non-restrictive manner in part a) of Fig. As illustrated in section 5, the device may also be put into a power-saving state (e.g., switched off) during the entire active DRX period.

[0076] In part b) of Fig. At time T0 within the inactive DRX period, the LP-WUR 254 detects a wake-up signal. Accordingly, the wireless device 25 considers that it could receive control data via the PDCCH during the next active DRX period. Since the active DRX period begins with an initial active sub-period, the LP-WUR 254 puts the MR unit 253 into the active state for the duration of this first active sub-period, during which the wireless device 25 can receive control data via the PDCCH. Because no control data should be received via the PDCCH during the first inactive sub-period, the MR unit 253 can be put into a power-saving state for the duration of this first inactive sub-period. However, the LP-WUR 254 monitors for a wake-up signal during this first inactive sub-period.The LP-WUR 254 detects a wake-up signal at time T1 within the first inactive sub-period, which means that the RAN can transmit control messages via the PDCCH during the following active sub-period, i.e., the second active sub-period. Accordingly, the LP-WUR 254 puts the MR unit 253 into the active state for the duration of the second active sub-period, during which the wireless device 25 can receive control data via the PDCCH. Since no control data is to be received via the PDCCH during the second inactive sub-period, the MR unit 253 can be put into a power-saving state for the duration of the second inactive sub-period. However, the LP-WUR 254 monitors for a wake-up signal during the second inactive sub-period. In the section described in part b) of... Fig. In the illustrated example 5, no wake-up signal is detected during the second inactive sub-period, meaning that the RAN does not intend to transmit control data via the PDCCH during the following sub-period, i.e., the third active sub-period. Accordingly, the MR unit 253 can be kept in a power-saving state during the third active sub-period. Likewise, the LP-WUR 254 does not need to monitor for a wake-up signal during the third inactive sub-period. Therefore, the LP-WUR 254 can be placed in a power-saving state during the third active sub-period. For example, the LP-WUR 254 can be switched off during the third active sub-period. In some examples, and as shown in a non-restrictive manner in part b) of Fig. As illustrated in Figure 5, the LP-WUR 254 can also be put into a power-saving state (e.g. switched off) during all active sub-periods of the active DRX period.

[0077] It is noted that the same power-saving state of MR Unit 253 can be used during both the inactive and active DRX periods. However, in some cases, it is also possible to use other power-saving states of MR Unit 253 during the inactive and active DRX periods, respectively. For example, the power-saving state used during the inactive DRX period may correspond to the very low power consumption state of MR Unit 253 discussed above, while the power-saving state used during the active DRX period may correspond to an intermediate power-saving state of MR Unit 253.

[0078] Fig. Figure 6 presents a diagram showing steps of an exemplary embodiment of a method 60 for exchanging data, which is implemented by a BS 30. Fig. Figure 7 presents a diagram illustrating the corresponding steps of an exemplary embodiment of a method 70 for exchanging data, implemented by a wireless device 25 of a UE 20. It is noted that the Fig. 6 and Fig. 7 only show a single inactive sub-period and a single active sub-period, but the corresponding steps can also be repeated if the active DRX period includes more than one inactive sub-period and / or more than one active sub-period.

[0079] As discussed above, the active DRX period comprises one or more inactive sub-periods and one or more active sub-periods, and the BS 30 is configured to transmit control data via the PDCCH to the wireless device 25 of a UE 20 only during one or more active sub-periods. In other words, no control data can be transmitted via the PDCCH to the wireless device 25 during inactive sub-periods of the active DRX period.

[0080] In the through Fig. In the non-restrictive example 6, the procedure 60 for exchanging data during an inactive sub-period of the active DRX period includes a step S60 of evaluating whether control data should be transmitted to the wireless device 25 via the PDCCH in the following active sub-period. If in the following active sub-period (reference S60a in Fig. 6) If control data is to be transmitted via the PDCCH, the data exchange procedure 60 comprises a step S61 of transmitting a wake-up signal to the wireless device 25 in the current inactive sub-period and a step S62 of transmitting control data via the PDCCH to the wireless device 25 during the following active sub-period. In return (reference S60b in Fig. 6) No wake-up signal is transmitted during the current inactive sub-period (and no control data is transmitted via the PDCCH to the wireless device 25 during the following active sub-period).

[0081] In some examples and how through Fig. As illustrated in Figure 6, the procedure 60 for exchanging data during an inactive DRX period includes a step S63 of evaluating whether control data should be transmitted to the wireless device 25 via the PDCCH during the following active DRX period. If, during the following active DRX period (reference S63a in Figure 6), control data should be transmitted to the wireless device 25 via the PDCCH, the procedure 60 will be evaluated as follows: Fig. 6) If control data is to be transmitted via the PDCCH, the data exchange procedure 60 includes step S64 of transmitting a wake-up signal to the wireless device 25 during the current inactive DRX period. In return (reference S63b in Fig. 6) No wake-up signal will be transmitted during the current inactive DRX period (and no control data will be transmitted via the PDCCH to the wireless device 25 during the following active DRX period).

[0082] In some examples, and as in the non-restrictive example of Fig. As illustrated in Figure 6, the data exchange procedure 60 includes step S65 of transmitting an active DRX period configuration to the wireless device 25. As discussed above, the active DRX period configuration can be transmitted, for example, in system information sent by the BS 30 and / or in a radio resource control (RRC) reconfiguration message transmitted to the wireless device 25 (when the wireless device 25 is in the RRC_CONNECTED state).

[0083] As discussed above, Fig. Figure 7 presents a diagram showing corresponding steps of an exemplary embodiment of a method 70 for exchanging data, which can be implemented by a wireless device 25 if the BS 30 implements the method 60 for exchanging data, which is Fig. 6 is illustrated, implemented.

[0084] As through Fig. As illustrated in Figure 7, the procedure 70 for exchanging data during an active DRX period includes a step S70 of performing a monitoring for a wake-up signal during an inactive sub-period by the LP-WUR 254 (while the MR unit 253 is in a power-saving state). If, during the current inactive sub-period (reference S70b in Figure 7), the LP-WUR 254 is inactive during the DRX period, the LP-WUR 254 is inactive during the DRX period. Fig. 7) If no wake-up signal is detected, no PDCCH monitoring is performed during the following active period, and the MR unit 253 can be maintained in a power-saving state for the duration of the following active period (and in some examples, the LP-WUR 254 does not monitor for a wake-up signal during the following active period and can be placed in a power-saving state). Conversely (reference S70a in Fig. 7) The data exchange procedure 70 comprises a step S71 of triggering a transition of the MR unit 253 to the active state and a step S72 of performing PDCCH monitoring during the following active sub-period.

[0085] In some examples and how through Fig. As illustrated in Figure 7, the procedure 70 for exchanging data during an inactive DRX period includes step S73 of performing a monitoring for a wake-up signal by the LP-WUR 254 (while the MR unit 253 is in a power-saving state).

[0086] If during the current inactive DRX period (reference S73b in Fig. 7) If no wake-up signal is detected, no PDCCH monitoring is performed during the following active DRX period, and the MR unit 253 can be kept in a power-saving state for the duration of the following active DRX period (and in some examples, the LP-WUR 254 does not monitor for a wake-up signal during the following active DRX period and can be placed in a power-saving state). Thus, steps S70, S71, and S72 discussed above are not performed.

[0087] In return (reference S73a in Fig. 7) Procedure 70 performs steps S70, S71 and S72 for exchanging data, as discussed above.

[0088] In some examples, and as in the non-restrictive example of Fig.As illustrated in Figure 7, the data exchange procedure 70 includes a step S74 of receiving an active DRX period configuration from the RAN, to be used during one or more active DRX periods. As discussed above, the active DRX period configuration is received, for example, in system information transmitted by the RAN 30 and / or in a radio resource control (RRC) reconfiguration message transmitted by the RAN.

[0089] It is emphasized that the present disclosure is not limited to the exemplary embodiments mentioned above. Variants of these exemplary embodiments are also within the scope of protection of the present disclosure.

Claims

[1] A method (70) for exchanging data in a wireless communication system, the method being implemented by a wireless device (25) of the wireless communication system, the wireless device comprising 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-WUR) (254) configured to monitor a wake-up signal transmitted by the RAN and, in response to detecting a wake-up signal, to trigger a transition of the MR unit to an active state, the wireless device (25) being configured with a discontinuous reception (DRX) cycle, the DRX cycle comprising an active DRX period,during which the wireless device (25) can receive control data from the RAN via a physical downlink control channel (PDCCH), and an inactive DRX period during which the wireless device (25) does not perform PDCCH monitoring, wherein the active DRX period comprises an inactive sub-period followed by an active sub-period, and wherein the method, in response to detecting, by the LP-WUR (254), a wake-up signal during an inactive DRX period, comprises, during the following active DRX period: - (S70) monitoring for a wake-up signal by the LP-WUR (254) during the inactive sub-period, wherein the MR unit is in a power-saving state, - in response to detecting a wake-up signal during the inactive sub-period: (S71) triggering a transition of the MR unit to the active state and (S72) performing PDCCH monitoring during the active sub-period. [2] The method (70) of claim 1, wherein the MR unit is maintained in the power saving state during the active sub-period in response to not detecting a wake-up signal during the inactive sub-period. [3] The method (70) of claim 2, wherein the LP-WUR, in response to not detecting a wake-up signal during the inactive sub-period, does not monitor for a wake-up signal during the active sub-period. [4] The method (70) of any preceding claim, comprising (S74) receiving an active DRX period configuration defining the inactive sub-period and the active sub-period in the active DRX period. [5] The method (70) of claim 4, wherein the configuration for an active DRX period is received in system information sent by the RAN and / or the configuration for an active DRX period is received in a radio resource control (RRC) reconfiguration message transmitted by the RAN. [6] The method (70) of any preceding claim, wherein if no wake-up signal is detected during the inactive DRX period, the wireless device (25) does not perform PDCCH monitoring during the following active DRX period. [7] Method (70) according to one of the preceding claims, wherein the active DRX period comprises a plurality of active sub-periods and / or the active DRX period comprises a plurality of inactive sub-periods. [8] The method (70) of any preceding claim, wherein the active DRX period begins with an active sub-period. [9] The method (70) of any preceding claim, wherein the MR unit is maintained in a power saving state during the inactive DRX period that is different from the power saving state used during the inactive sub-period of the active DRX period. [10] A wireless device (25) comprising at least one memory (251) and at least one processor (250) configured to perform a method (70) according to any one of the preceding claims. [11] A user equipment (UE) (20) comprising a wireless device according to claim 10. [12] A method (60) for exchanging data in a wireless communication system, the method being implemented by a base station (BS) (30) of a radio access network (RAN) of the wireless communication system, the BS being configured to exchange data with a wireless device (25), the wireless device comprising a main radio (MR) unit (253) and a low power wake-up receiver (LP-WUR) (254), the LP-WUR being configured to detect a wake-up signal transmitted by the BS and, in response to detecting a wake-up signal transmitted by the BS, to trigger a transition of the MR unit to an active state, the BS being configured with a discontinuous reception (DRX) cycle, the DRX cycle comprising an active DRX period,during which the BS can transmit control data to the wireless device via a physical downlink control channel (PDCCH), and an inactive DRX period during which the BS does not transmit control data to the wireless device via the PDCCH, wherein the active DRX period comprises at least one inactive sub-period and at least one active sub-period, and wherein the BS is configured to transmit control data to the wireless device via the PDCCH only in the at least one active sub-period. [13] The method (60) of claim 12, comprising, in response to determining that control data is to be transmitted in an active sub-period following an inactive sub-period of the active DRX period: (S60) transmitting a wake-up signal to the wireless device in that inactive sub-period. [14] The method (60) of any one of claims 12 to 13, comprising, in response to determining that control data is to be transmitted in an active DRX period: (S63) transmitting a wake-up signal to the wireless device in the inactive DRX period following that active DRX period. [15] The method (60) of any one of claims 12 to 14, comprising (S65) transmitting an active DRX period configuration to the wireless device, wherein the active DRX period configuration defines the at least one inactive sub-period and the at least one active sub-period within the active DRX period. [16] The method (60) of claim 15, wherein the configuration for an active DRX period is transmitted in system information sent by the RAN and / or the configuration for an active DRX period is transmitted in a radio resource control (RRC) reconfiguration message transmitted by the wireless device. [17] The method (60) of any one of the preceding claims 12 to 16, wherein the active DRX period begins with an active sub-period. [18] Base station (BS - base station) (30), comprising at least one memory (301) and at least one processor (300) configured to carry out a method (60) according to one of claims 12 to 17. [19] A wireless communication system comprising at least one base station (30) according to claim 18 and at least one user device (20) according to claim 11. [20] A computer program product (252, 302) comprising instructions that, when executed by at least one processor, configure the at least one processor to perform a method (70) according to any one of claims 1 to 9 or a method (60) according to any one of claims 12 to 17. [21] A computer-readable storage medium comprising instructions that, when executed by at least one processor, configure the at least one processor to perform a method (70) according to any one of claims 1 to 9 or a method (60) according to any one of claims 12 to 17.

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