Method and apparatus for performing energy saving on a UE that initiates an uplink transmission when it is performing a discontinuous reception

Abstract

The present disclosure relates to methods and devices for enabling a user equipment (UE) (20) to reduce its energy consumption during a discontinuous reception (DRX) cycle when the UE has to initiate an uplink (UL) transmission.

Description

Technical area

[0001] The present disclosure relates to wireless communication systems, and more particularly, to methods and apparatus for conserving power 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 UE periodically enters a sleep state for a sleep period, during which a physical downlink control channel (PDCCH) is not monitored, before waking up for a wake period to monitor the PDCCH for possible downlink control data. The amount of energy that can be saved depends on how long and how frequently the UE remains in the sleep state. Obviously, the longer the UE remains in the sleep state, the greater the amount of energy saved.

[0003] To improve energy savings without sacrificing latency in 5G or New Radio (NR) wireless 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 energy consumption during periods without signaling or data traffic. If UEs were able to wake up only when triggered, e.g., by a page, energy consumption could be drastically reduced. As explored by 3GPP, this is achieved by deploying 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 wireless communication unit, and the LT-WUR corresponds to a wireless communication unit used to monitor a wake-up signal during low-power conditions. 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 a state in which the MR unit can exchange data with a radio access network (RAN) of the wireless communication system. The low power state corresponds to any state in which the MR unit cannot exchange data with the RAN.

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

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

[0009] Thus, power consumption is reduced by placing the MR unit in a low-power state (e.g., turned off). The MR unit does not need to wake up periodically, and 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 MR 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 that includes an active DRX period, during which the UE must wake up for the awake period, and an inactive DRX period, during which the UE enters the sleep state for the dormant period. Based on the DRX cycle, it is only possible to use the LP-WUR to wake up the UE for the next active DRX period if a wake-up signal is detected during the current inactive DRX period. If no wake-up signal is received during the inactive DRX period, the UE can skip the next active DRX period, and the MR unit can remain in a power-saving state (without monitoring the PDCCH) during the next active DRX period.

[0011] Thus, the LP-WUR can only be used to wake up the UE for an active DRX period if the RAN intends to transmit control data to the UE over the PDCCH during this active DRX period.

[0012] However, the MR unit must also be placed in the active state to perform PDCCH monitoring after the UE initiates a UL (uplink) transmission. For example, the UE can initiate a UL transmission by transmitting a random preamble on a random access channel (RACH) to the RAN or by transmitting a scheduling request (SR) message to the RAN. After such a UL transmission (RACH or SR) is initiated by the UE, the UE must monitor the PDCCH with its MR unit in the active state (to receive a random access response (RAR) or a UL grant). However, such a UL transmission may be initiated by the UE itself during an inactive DRX period, which requires that the MR unit be transitioned to the active state during this inactive DRX period.

[0013] There is therefore a need to further reduce energy consumption. Brief description

[0014] The present disclosure aims to improve the situation. In particular, the present disclosure aims to address at least some of the limitations of the prior art discussed above. In particular, the present disclosure aims to propose a solution for reducing power consumption during inactive DRX periods of a DRX cycle.

[0015] In particular, the present disclosure aims, at least in some embodiments, to propose a solution that is applicable even to UEs that are not equipped with an LP-WUR.

[0016] 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 comprising a main radio (MR) unit configured to exchange data with a radio access network (RAN) of the wireless communication system, the wireless device being configured with a discontinuous reception (DRX) cycle, the DRX cycle comprising an active DRX period during which the MR unit may monitor a downlink (DL) to detect a RAN-initiated downlink (DL) transmission, and an inactive DRX period during which the MR unit does not perform DL monitoring to detect a RAN-initiated DL transmission, the method comprising, in response to determining, by the wireless device,during a momentary inactive DRX period that an uplink (UL) transmission is to be initiated by the wireless device, comprising: , - Assess whether the UL transmission can be postponed to a subsequent active DRX period, - in response to determining that the UL transmission can be postponed to a subsequent active DRX period: postponing the UL transmission to a subsequent active DRX period, - in response to determining that the UL transmission cannot be postponed to a subsequent active DRX period: initiating the UL transmission during the current inactive DRX period.

[0017] In some embodiments, the method according to the first aspect may further comprise one or more of the following optional features, contemplated either alone or in any technically possible combination.

[0018] In some embodiments of the method according to the first aspect, the MR unit is in a power saving mode at the beginning of the inactive DRX period and, if the wireless device determines during the current inactive DRX period that a UL transmission should be initiated by the wireless device: - the MR unit is maintained in power saving mode in response to determining that the UL transmission can be postponed to a subsequent active DRX period, - in response to determining that the UL transmission cannot be postponed to a subsequent active DRX period, the MR unit is transitioned to an active state during the current inactive DRX period.

[0019] In some embodiments of the method according to the first aspect, evaluating whether the UL transmission can be postponed to a subsequent active DRX period comprises evaluating whether at least one subsequent active DRX period is set to begin within a predetermined time interval.

[0020] In some embodiments of the method according to the first aspect, different time intervals are each associated with different priority levels and assessing whether the UL transmission can be postponed to a subsequent active DRX period comprises the following: - Determining a priority level associated with the UL transmission to be initiated, - Selecting the time interval associated with the specific priority level.

[0021] In some embodiments of the method according to the first aspect, the priority level of the UL transmission to be initiated is determined based on a logical channel (LCH) for which the UL transmission is to be initiated.

[0022] In some embodiments of the method according to the first aspect, a high priority level is associated with a time interval having a longer duration than a time interval associated with a low priority level.

[0023] In some embodiments, the method according to the first aspect comprises previously receiving, from the RAN, a time interval configuration for each time interval.

[0024] In some embodiments of the method according to the first aspect, each time interval configuration is received in system information sent by the RAN and / or in a radio resource control (RRC) message transmitted by the RAN.

[0025] In some embodiments of the method according to the first aspect: - the wireless device comprises a low-power wake-up receiver (LP-WUR) 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 method comprises, in response to determining that a plurality of subsequent active DRX periods are scheduled to begin within the time interval, initiating the UL transmission in a subsequent active DRX period selected from the plurality of subsequent active DRX periods based on a wake-up signal detection during the time interval.

[0026] In some embodiments of the method according to the first aspect, the following active DRX period selected from the plurality of following active DRX periods corresponds to the following: - the active DRX period immediately following an inactive DRX period within the time interval during which a wake-up signal is detected by the LP-WUR, - or, in response to not detecting a wake-up signal in an inactive DRX period within the time interval: the last following active DRX period of the plurality of following active DRX periods.

[0027] 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 of the embodiments of the first aspect.

[0028] According to a third aspect, the present disclosure relates to a user equipment (UE) comprising a wireless device according to any of the embodiments of the present disclosure.

[0029] According to a fourth aspect, the present disclosure relates to a method for exchanging data in a wireless communication system, wherein the method is implemented by a base station (BS) of a radio access network (RAN) of the wireless communication system, wherein the BS is configured to exchange data with a main radio (MR) unit of a wireless device, wherein the BS is configured with a discontinuous reception (DRX) cycle, wherein the DRX cycle comprises an active DRX period during which the BS can initiate a downlink (DL) transmission to the MR unit of the wireless device, and an inactive DRX period during which the BS cannot initiate a DL transmission to the MR unit of the wireless device.wherein the method comprises transmitting a time interval configuration to the wireless device for configuring a time interval in that wireless device, the time interval to be used by the wireless device to determine whether an uplink (UL) transmission to be initiated in an inactive DRX period can be postponed to a subsequent active DRX period.

[0030] In some embodiments, the method according to the fourth aspect may further comprise one or more of the following optional features, contemplated either alone or in any technically possible combination.

[0031] In some embodiments of the method according to the fourth aspect, the BS transmits to the wireless device different time interval configurations, each associated with different priority levels.

[0032] In some embodiments of the method according to the fourth aspect, each time interval configuration is transmitted in system information sent by the BS and / or in a radio resource control (RRC) message.

[0033] In some embodiments of the method according to the fourth aspect: - the wireless device comprises a low-power wake-up receiver (LP-WUR) configured to monitor a wake-up signal transmitted by the BS and, in response to detecting a wake-up signal, to trigger a transition of the MR unit to an active state, - the method comprises, in response to determining that a DL transmission should be initiated by the BS in an active DRX period following a current inactive DRX period: transmitting a wake-up signal to the wireless device in the current inactive DRX period.

[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 perform a method according to any 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 of the embodiments of the present disclosure and at least one user equipment according to any of the embodiments of the present disclosure.

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

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

[0038] The invention will be better understood by reading the following description, given as a non-limiting example and with reference to the figures, which show: - 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: a flowchart illustrating an example of a method for exchanging data implemented by a wireless device of a UE, - Fig. 5: schematic representations of different scenarios for an example that includes a time interval for evaluating whether a UL transmission can be postponed, - Fig. 6: schematic representations of an example containing different time intervals for evaluating whether a UL transmission can be postponed, - Fig. 7: schematic representations of different scenarios for an example including wake-up signal detection for selecting a subsequent active DRX period to initiate a postponed UL transmission, - Fig. 8: a flowchart illustrating an example of a method for exchanging data implemented by a BS.

[0039] In these figures, reference numerals that are identical from one figure to another indicate identical or similar elements. For clarity, the elements shown are not to scale unless expressly stated otherwise. Detailed description

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

[0041] In general, all terms used herein should be interpreted according to their usual meaning in the relevant technical field, unless another meaning is clearly indicated and / or clear from the context in which it is used. All references to an element, device, component, means, step, etc. should be openly construed as referring to at least one instance of the element, device, component, means, step, etc., unless expressly stated otherwise.Likewise, the order of steps of any methods disclosed herein, particularly in the figures, is provided for illustrative purposes only and does not imply any limitation on the present disclosure, which may be applied with the same steps performed in a different order and / or with all or part of the steps performed in parallel or together, unless a step is expressly described as following or preceding a step and / or where it is implicit that a step must follow or precede another step. Likewise, steps depicted in a figure that are surrounded by a dashed line are to be considered optional for the embodiment depicted in that figure.Any feature of any of the embodiments disclosed herein may be applied to any other embodiment whenever appropriate. Likewise, any advantage of any of the embodiments may be applicable to any other embodiment, and vice versa. Other objects, features, and advantages of the included embodiments will become apparent from the following description.

[0042] Fig. Figure 1 schematically illustrates an example of a wireless communication system, which may be, for example, a 5G NR wireless communication system. In particular, Fig. 1 depicts a RAN of the wireless communication system used to exchange data with UEs 20 via radio signals. The RAN can, for example, send data to the UEs 20 (DL - downlink), such as data received from a core network (CN - core network, not shown in the figures). The RAN can also receive data from the UEs 20 (UL - uplink), and this data can be forwarded to the CN.

[0043] In the Fig. In the example illustrated in Figure 1, the RAN includes a base station (BS) 30. Of course, the RAN may include more than one BS 30 to expand the coverage area of ​​the wireless communication system. Each of these BSs may be referred to as an NB, eNodeB (or eNB), gNodeB (or gNB in ​​the case of a 5G NR wireless communication system), an access point, or the like, depending on the wireless communication standard(s) implemented.

[0044] In the Fig. In the example illustrated in Figure 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.

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

[0046] Such a wireless device 25 may be incorporated in a UE 20 as shown by Fig. 2. The UE 20 may be, for example, a mobile phone, a wireless modem, a wireless communication device, a handheld device, a laptop computer, or the like. The UE 20 may 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 executing applications that require exchanging data with remote receivers via the wireless device 25.

[0047] As through Fig. 2, the wireless device 25 includes one or more processors 250 and one or more memories 251. The one or more processors 250 may include, for example, a central processing unit (CPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), etc. The one or more memories 251 may include any type of computer-readable volatile and non-volatile memory (magnetic hard disk, solid-state memory, optical disk, electronic memory, etc.).The one or more memories 251 may store a computer program product 252 in the form of a set of program-encoded instructions to be executed by the one or more processors 250 to implement all or part of the steps of a method for exchanging data performed on the side of a UE according to any of the embodiments disclosed herein.

[0048] As through Fig. 2, the wireless device 25 also includes a main radio (MR) unit 253. 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 may implement one or more wireless communication protocols and may be, for example, 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] As in the non-limiting example of Fig. 2, the wireless device 25 may optionally include a low power wake-up receiver (LP-WUR) 254.

[0050] It is emphasized that, unless otherwise stated, the embodiments of the present disclosure may be applied with a wireless device 25 having only an MR unit 253 and no LP-WUR 254. Of course, increased power savings may be achieved with an LP-WUR 254, as discussed above. When present, 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 may take any form that allows it to be detected at low power consumption. Non-limiting 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 explicitly expected to be capable of detecting such a specific 5G NR signal.

[0051] 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. Thus, the LP-WUR 254 may be unidirectional, meaning it has only receive (DL) capabilities and no transmit (UL) capabilities. However, in some examples, the LP-WUR 254 may also have transmit capabilities, allowing it to also transmit data to the RAN (UL).

[0052] As discussed above, the MR unit 253 can be placed in an active state or a power saving state.

[0053] The active state corresponds to any state in which the MR unit 253 can exchange data with the RAN.

[0054] The power-saving state corresponds to a state in which the MR unit 253 cannot exchange data with the RAN. For example, the power-saving state corresponds to the state in which the MR unit 253 is in the sleep state. If the wireless device 25 includes an LP-WUR 254, the MR unit 253 does not need to wake up periodically in the power-saving state, and the MR unit 253 can be in an extremely deep sleep state and may even be turned off, since the LP-WUR 254 can be used to turn on the MR unit 253. It is noted that it is possible to consider different power-saving states for the MR unit 253, each having a different average power consumption.For example, it is possible to consider a very low power state having the lowest average power consumption, as well as one or more intermediate power-saving states having an average power consumption greater than the average power consumption of the very low power state. For example, the very low power state may correspond to the one in which the MR unit 253 is turned off, and an intermediate power-saving state may correspond to the one in which the MR unit 253 is in the sleep state without being turned off.

[0055] It should be noted that in some examples, the LP-WUR 254 (if present) may also be configured to trigger the MR unit 253 when other conditions are verified. For example, the LP-WUR 254 may be configured to trigger the MR unit 253 when 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 if, for example, the wireless device 25 has moved out of the coverage area of ​​the wake-up signal. Of course, the duration of this timer should be sufficiently long to ensure that the MR unit 253 can remain in a power-saving state for long periods of time.

[0056] Fig. 3 schematically illustrates an example of a BS 30 suitable for implementing any method discussed in the present disclosure as well as performed by the RAN.

[0057] As through Fig. 3, the OS 30 includes one or more processors 300 and one or more memories 301. The one or more processors 300 may include, for example, a 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 hard disk, solid-state memory, optical disk, electronic memory, etc.). The one or more memories 301 may store a computer program product 302 in the form of a set of program-encoded instructions to be executed by the one or more processors 300 to implement all or part of the steps of a method for exchanging data performed at the RAN side according to any of the embodiments disclosed herein.

[0058] As through Fig. 3, the BS 30 also includes a wireless communication unit 303 configured to exchange data with UEs 20 using radio signals, and in particular with MR units 253 of wireless devices 25 included in these UEs 20. The wireless communication unit 303 may be, for example, 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 in the non-limiting example of Fig. 3, the BS 30 may optionally include a wake-up signal transmitter (WUT) 304 configured to transmit wake-up signals to UEs having a wireless device 25 including an LP-WUR 254. In the embodiment represented by Fig. In the example illustrated in Figure 3, the WUT 304 is shown as separate from the wireless communication unit 303. However, the WUT 304 may also be included in the wireless communication unit 303, e.g., when the wireless communication unit 303 is a 5G NR transceiver and when the wake-up signal is a specific 5G NR signal.

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

[0061] As in the non-limiting example of Fig. 3, the BS 30 may also optionally include 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 that are wired (including fiber optic) and / or wireless.

[0062] As discussed above, the present disclosure aims to further reduce power consumption when performing discontinuous reception (DRX). Note that DRX also includes extended DRX (eDRX) as defined by 3GPP. In DRX, wireless device 25 operates according to a DRX cycle, which includes: - an active DRX period during which the MR unit 253 of the wireless device 25 can monitor a DL to detect a RAN-initiated DL transmission (e.g., control data transmitted to the wireless device 25 via the PDCCH), and - an inactive DRX period during which the MR unit 253 does not perform DL monitoring to detect a RAN-initiated DL transmission.

[0063] By a “RAN-initiated” DL transmission, the authors mean that the DL transmission from the RAN is not triggered by a previous UL transmission from the wireless device 25.

[0064] When performing DL (e.g., PDCCH) monitoring during an active DRX period, the MR unit 253 is typically in the active state. Conversely, the MR unit 253 may be in a power-saving state when DL monitoring is not required (e.g., during an inactive DRX period).

[0065] In the context of this DRX cycle, the present disclosure relates to how UL (uplink) transmissions initiated by the wireless devices 25 may be managed to reduce power consumption during inactive DRX periods.

[0066] By a "wireless device-initiated" UL transmission, the authors mean that the UL transmission from wireless device 25 is not triggered by a prior DL ​​transmission from a RAN BS 30. As discussed above, a UL transmission initiated by wireless device 25 typically triggers a DL transmission by the RAN, so a UL transmission initiated by wireless device 25 typically requires MR unit 253 to be placed in the active state to perform DL (e.g., PDCCH) monitoring. MR unit 253 may also be placed in the active state to perform the UL transmission initiated by wireless device 25. However, in some examples, it is also possible to use the LP-WUR 254 to perform the UL transmission initiated by the wireless device 25 (assuming an LP-WUR 254 is present and has transmission capabilities).

[0067] Thus, in the prior art, if the wireless device 25 initiates a UL transmission during an inactive DRX period, the MR unit 253 may need to be put into the active state during that inactive DRX period to perform at least one DL (e.g., PDCCH) monitoring for a DL transmission triggered by the UL transmission initiated by the wireless device 25, which increases power consumption during the inactive DRX period.

[0068] To reduce power consumption during inactive DRX periods due to UL transmissions initiated by wireless device 25, it is proposed to attempt to postpone the UL transmission to a subsequent active DRX period, if possible. Since the MR unit 253 may need to be placed in the active state for the purpose of performing DL monitoring to detect DL transmissions initiated by the RAN during the active DRX periods, it is indeed possible to benefit from this placement in the active state to continue performing DL monitoring for DL ​​transmissions triggered by the UL transmission initiated by wireless device 25.Therefore, if the UL transmission can be postponed, it is possible to reduce the power consumption during the inactive DRX period and make more efficient use of the active DRX period, during which the MR unit 253 can be placed in the active state to perform DL monitoring, both for detecting DL transmissions initiated by the RAN and for receiving DL transmissions that respond to the UL transmission initiated by the wireless device 25.

[0069] Fig. 4 illustrates a diagram showing steps of an exemplary embodiment of a method 40 for exchanging data implemented by a wireless device 25 of a UE 20. Fig. 8 illustrates a diagram showing respective steps of an exemplary embodiment of a method 80 for exchanging data implemented by a BS 30 of the RAN.

[0070] As through Fig. 4, the method 40 for exchanging data includes a step S40 of determining, during a current inactive DRX period, that a UL request should be initiated by the wireless device 25. For example, the UE 20 may have data related to an application layer running in the UE 20 that needs to be transmitted to the RAN. In such a case, the UE 20 may notify the wireless device 25 that it needs to transmit data to the RAN, and such notification from the application layer of the UE 20 may be used to determine that a UL transmission should be initiated by the wireless device 25.

[0071] As through Fig. 4, the method 40 for exchanging data comprises a step S41 of evaluating whether the UL transmission can be postponed to a following active DRX period.

[0072] If it is determined that the UL transmission is to be postponed to a subsequent active DRX period (reference symbol S41a in Fig. 4), then the method 40 for exchanging data includes a step S42 of postponing the UL transmission to a subsequent active DRX period and, once in that subsequent active DRX period, a step S43 of initiating the UL transmission. As discussed above, in some examples, the step S43 of initiating the UL transmission may include transmitting a random preamble in the RACH or transmitting an SR message to the RAN. Indeed, the SR method allows a wireless device 25 to request UL resources to transmit data to the RAN. For that purpose, the wireless device 25 may be allocated SR (UL) resources, which may be used to transmit a UL request (an SR message requesting additional UL resources for an upcoming transmission).Such SR resources may be allocated, for example, by the RAN of a wireless device 25 in a radio resource control (RRC) connected (RRC_CONNECTED) state or in an RRC inactive (RRC_INACTIVE) state.

[0073] Conversely, if it is determined that the UL transmission does not fall on a subsequent active DRX period (reference sign S41b in Fig. 4), then the method 40 for exchanging data includes a step S44 of initiating the UL transmission during the current inactive DRX period. Similarly, as discussed above, in some examples, the step S44 of initiating the UL transmission may include transmitting a random preamble in the RACH or transmitting an SR message to the RAN.

[0074] Generally, the MR unit 253 of the wireless device 25 is in the power-saving state during the current inactive DRX period when it is determined that a UL transmission should be initiated. If it is determined that the UL transmission can be postponed (reference symbol S41a in Fig. 4), then the MR unit 253 may be maintained in a power-saving state during step S42 of postponing the UL transmission to a subsequent active DRX period, and the MR unit 253 may only be transitioned to the active state during this subsequent active DRX period. If it is determined that the UL transmission cannot be postponed (reference symbol S41b in Fig. 4), then the MR unit 253 may be transitioned to the active state during the step S44 of initiating the UL transmission during the current inactive DRX state, e.g., to initiate the UL transmission and to perform DL monitoring for a DL transmission responding to the initiated UL transmission.

[0075] Various methods may be used to evaluate whether a UL transmission to be initiated can be postponed to a subsequent active DRX period, and the choice of a specific method corresponds to a specific, but non-limiting, embodiment of the present disclosure.

[0076] For example, the evaluation of whether the UL transmission can be postponed to a subsequent active DRX period may be based on a predetermined time interval, e.g., having a predetermined duration. For example, the time interval may be started as soon as it is determined that a UL transmission needs to be initiated by the wireless device 25. If it is determined that at least one subsequent active DRX period should begin within this time interval (i.e., it is determined that the time interval ends after the start of at least one subsequent active DRX period), then it may be considered that the UL transmission is postponed to a subsequent active DRX period (reference symbol S41a in Fig. 4). Conversely, if it is specified that no subsequent active DRX period shall start within this time interval (i.e., it is specified that the time interval shall end before the start of any active DRX period), then it may be considered that the UL transmission is not postponed to a subsequent active DRX period (reference sign S41b in Fig. 4) can be postponed.

[0077] Fig. Figure 5 schematically illustrates various scenarios that include such a predefined time interval. Fig. 5, it is assumed that the time interval under consideration has a duration ΔT and that it is to be started at a time T0 in the current inactive DRX period when it is determined that a UL transmission is to be initiated by the wireless device 25.

[0078] In the case of part a) of Fig. 5, the time interval ends before the start of the active DRX period immediately following the current inactive DRX period. In such a case, it is determined that the UL transmission will not be delayed until a subsequent active DRX period (reference symbol S41b in Fig. 4) can be postponed.

[0079] In the case of part b) of Fig. 5, the time interval ends during the active DRX period immediately following the current inactive DRX period. In such a case, it is determined that the UL transmission is delayed until the active DRX period immediately following the current inactive DRX period (reference symbol S41a in Fig. 4) follows, can be postponed.

[0080] In the case of part c) of Fig. 5, it is determined that a plurality of subsequent active DRX periods begin within the time interval (ie, before T0 + ΔT). In such a case, it is determined that the UL transmission is postponed to a subsequent active DRX period (reference symbol S41a in Fig. 4) can be postponed. Since a plurality of subsequent active DRX periods are specified to begin within the time interval, the UL transmission can be initiated in any active DRX period selected from this plurality of subsequent active DRX periods. The selection of a subsequent active DRX period in such a case is discussed in more detail below.

[0081] In some cases, when assessing whether the UL transmission can be postponed to a subsequent active DRX period, it is possible to consider different time intervals, which may, for example, have different predetermined durations.

[0082] Fig. Figure 6 schematically illustrates an example containing various predefined time intervals. In particular, Fig. 6 three different time intervals are considered: - a first time interval having a duration ΔT1, - a second time interval having a duration ΔT2 greater than ΔT1, - a third time interval having a duration ΔT3 greater than ΔT2.

[0083] In the Fig. 6, each time interval is started at a time T0 in the current inactive DRX period when it is determined that a UL transmission should be initiated by the wireless device 25.

[0084] Part a) of Fig. 6 represents the case where the first time interval is considered. As shown by part a) of Fig. 6, the first time interval ends before the start of any subsequent active DRX period. Accordingly, upon consideration of the first time interval, it is determined that the UL transmission cannot be postponed (reference symbol S41b in Fig. 4).

[0085] Part b) of Fig. 6 represents the case where the second time interval is considered. As shown by part b) of Fig. 6, the second time interval ends during the active DRX period immediately following the current inactive DRX period. Accordingly, upon viewing the second time interval, it is determined that the UL transmission can be postponed (reference symbol S41b in Fig. 4), but only to the active DRX period immediately following the current active DRX period.

[0086] Part c) of Fig. 6 represents the case where the third time interval is considered. As shown by part c) of Fig. 6, the third time interval is such that it covers the beginning of three subsequent active DRX periods. Accordingly, upon considering the third time interval, it is determined that the UL transmission can be postponed (reference symbol S41b in Fig. 4). In practice, the UL transmission can be postponed to any of the three following active DRX periods (denoted by #1, #2 and #3 in Fig. 6) which are specified to start within the third time interval (i.e. before T0 + ΔT).

[0087] For example, the different time intervals that can be considered during step S41 can be associated with respective different priority levels. For example, it is possible to consider a time interval that has a short duration (e.g., the first time interval having duration ΔT1) for a UL transmission that has a high priority level, and to use a time interval that has a shorter duration (e.g., the third time interval having duration ΔT3) for a UL transmission that has a lower priority level. Thus, high-priority UL transmissions can be postponed to a subsequent active DRX period less frequently than low-priority UL transmissions, thereby reducing the latency for high-priority UL transmissions.

[0088] In such a case, for example, wireless device 25 may determine the priority level of the UL transmission to be initiated and then use the time interval associated with the determined priority level. For example, if it is determined that the UL transmission to be initiated has a high priority level, wireless device 25 may select the first time interval. Conversely, if it is determined that the UL transmission to be initiated has a low priority level, wireless device 25 may select the second time interval or the third time interval.

[0089] In some cases, different logical channels (LCHs) associated with respective different priority levels may be defined between the wireless device 25 and the RAN. In such cases, the priority level of the UL transmission to be initiated may be determined based on the LCH for which the UL transmission is to be initiated. For example, it is possible to define three different LCHs, e.g., a first logical channel LCH1 having a high priority level, a second logical channel LCH2 having a medium priority level, and a third logical channel LCH3 having a low priority level. In such a case: - a UL transmission related to the first logical channel LCH1 may use the first time interval to determine whether it can be postponed to a subsequent active DRX period, - a UL transmission related to the second logical channel LCH2 may use the second time interval to determine whether it can be postponed to a subsequent active DRX period, - a UL transmission related to the third logical channel LCH3 may use the third time interval to determine whether it can be postponed to a subsequent active DRX period.

[0090] For example, if data is available on more than one LCH to be transmitted to the RAN, wireless device 25 may use the time interval associated with the LCH having the higher priority level among the LCHs on which data is available. For example, if data is available on the second logical channel LCH2 and the third logical channel LCH3, wireless device 25 may use the second time interval. In other examples, it is also possible to handle these logical channels separately, via separate UL transmissions.

[0091] In some examples, the one or more time intervals may be predefined at the wireless device 25. In other examples, each time interval may be determined by the wireless device 25 or by the RAN. In the latter case, and as described in a non-limiting manner by Fig. 4, the method 40 for exchanging data includes a prior step S45 of receiving, from the RAN, a time interval configuration (e.g., defining the duration of the time interval) for each time interval. For example, such a time interval configuration may be received by the wireless device 25 in system information sent by a BS 30 of the RAN and / or in a radio resource control (RRC) message transmitted by a BS 30 of the RAN. Of course, other control messages may be used by the RAN to transmit a time interval configuration to the wireless device 25.

[0092] As discussed above, in some cases there may be more than one subsequent active DRX period during which the postponed UL transmission may be initiated (see, for example, part c) of Fig. 5). In such a case, various selection strategies may be considered, and the selection of a specific strategy corresponds to a specific, but non-limiting, embodiment of the present disclosure. Various strategies are discussed below as non-limiting examples.

[0093] According to one example, it is possible to always initiate the postponed UL transmission in the first consecutive active DRX period, i.e., the active DRX period immediately following the current inactive DRX period. Such a selection strategy allows limiting the latency introduced by postponing the UL transmission.

[0094] According to another example, it is possible to always initiate the postponed UL transmission in the last following active DRX period, i.e. the following active DRX period which is the last one to start within the considered time interval.

[0095] According to another example, it is possible to randomly select a subsequent active DRX period from the plurality of subsequent active DRX periods that can be considered for postponing the UL transmission.

[0096] According to another example, it is possible to rely on wake-up signal detection to select a subsequent active DRX period when the wireless device 25 includes an LP-WUR 254.

[0097] Indeed, as discussed above, wireless device 25 may be configured to perform PDCCH monitoring during an active DRX period only if it detects a wake-up signal during the previous inactive DRX period. Thus, the RAN may transmit a wake-up signal to wireless device 25 during an inactive DRX period to notify wireless device 25 that this RAN will initiate a DL transmission during the next active DRX period. If no wake-up signal is detected by LP-WUR 254 during the current inactive DRX period, then wireless device 25 may skip PDCCH monitoring during the next active DRX period (and MR unit 253 may remain in the power-saving state).

[0098] Thus, if the wireless device 25 needs to initiate a UL transmission during a subsequent active DRX period, it may rely on wake-up signal detection to attempt to initiate the UL transmission during a subsequent active DRX period during which the RAN also intends to initiate a DL transmission.

[0099] Fig. Figure 7 schematically illustrates various scenarios that include such a selection based on wake-up signal detection. In the Fig. In the examples illustrated in Figure 7, it is assumed in a non-limiting manner that it is determined that three possible subsequent active DRX periods should begin within the considered time interval of duration ΔT. Thus, three possible subsequent active DRX periods (denoted by #1, #2, and #3, respectively, in Fig. 7) during which the postponed UL transmission can be initiated.

[0100] Part a) illustrates an example in which the RAN initiates a DL transmission during one of the three possible active DRX periods. In this example, the DL transmission is initiated during the second possible subsequent active DRX period (#2). Accordingly, the RAN does not transmit a wake-up signal during the inactive DRX period preceding the first possible subsequent active DRX period, and the MR unit 253 of the wireless device 25 may remain in a power-saving state (e.g., powered off) during the first possible subsequent active DRX period because no UL transmission is to be initiated and no DL monitoring is to be performed to detect a RAN-initiated DL transmission. The RAN transmits a wake-up signal to the wireless device 25 at a time T1 during the inactive DRX period preceding the second possible subsequent active DRX period.Accordingly, the MR unit 253 must be transitioned to the active state to perform PDCCH monitoring during the second possible active DRX period (#2), and the wireless device 25 takes advantage of this by initiating the UL transmission also during this second possible active DRX period (#2).

[0101] Part b) illustrates an example in which the RAN does not initiate a DL transmission during one of the three possible active DRX periods. Accordingly, no wake-up signal is transmitted by the RAN during the inactive DRX periods within the considered time interval. In such a case, since no wake-up signal is detected, the wireless device 25 initiates the UL transmission during the third possible subsequent active DRX period, as it is the last possible subsequent active DRX period during which the postponed UL transmission can be initiated by the wireless device 25. Thus, the MR unit 253 of the wireless device 25, while in a power-saving state during the first and second possible subsequent active DRX periods, is transitioned to the active state during the third possible subsequent active DRX period to initiate the postponed UL transmission.

[0102] As discussed above, Fig. 8 is a diagram showing corresponding steps of an exemplary embodiment of a method 80 for exchanging data that may be implemented by a BS 30 when the wireless device 25 executes the method 40 for exchanging data implemented by Fig. 4 (containing the optional step S45).

[0103] As through Fig. 8, the method 80 for exchanging data includes a step S80 of transmitting a time interval configuration to the wireless device 25 to configure, in that wireless device 25, the time interval to be used by the wireless device 25 during step S41. As discussed above, the BS 30 may transmit a plurality of time interval configurations, for example, for configuring, in the wireless device 25, different time intervals each associated with different priority levels. As discussed above, each time interval configuration may be transmitted in system information sent by the BS and / or in an RRC message. Of course, other control messages may be used by the BS 30 to transmit a time interval configuration to the wireless device 25.

[0104] In some examples, the BS 30 may include a WUT 304, which may be used to transmit a wake-up signal to an LP-WUR 254 of the wireless device 25. In such a case, the method 80 for exchanging data, possibly during an inactive DRX period, may include a step S81 of evaluating whether a DL transmission should be initiated by the BS 30 in the next active DRX period. If in the next active DRX period (reference numeral S81a in Fig. 8) a DL transmission is to be initiated, the method 80 for exchanging data comprises a step S82 of transmitting a wake-up signal to the wireless device 25 in the current inactive DRX period and a step S83 of initiating the DL transmission during the next active DRX period. In turn (reference symbol S81b in Fig.8) No wake-up signal is transmitted during the current inactive DRX period, and no DL transmission is initiated by the BS 30 during the active DRX period immediately following the current inactive DRX period. As discussed above, such a wake-up signal may be used by the wireless device 25 to select a subsequent active DRX period for initiating a postponed UL transmission if a plurality of subsequent active DRX periods can be used to initiate that postponed UL transmission.

[0105] It is emphasized that the present disclosure is not limited to the above exemplary embodiments. Variants of the above exemplary embodiments are also within the scope of the present disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] Report TR 38.869

[0003]

Claims

[1] A method (40) for exchanging data in a wireless communication system, the method being implemented by a wireless device (25) comprising a main radio (MR) unit (253) configured to exchange data with a radio access network (RAN) of the wireless communication system, the wireless device (25) being configured with a discontinuous reception (DRX) cycle, the DRX cycle comprising an active DRX period during which the MR unit can monitor a downlink (DL) to detect a RAN-initiated downlink (DL) transmission, and an inactive DRX period during which the MR unit does not perform DL monitoring to detect a RAN-initiated DL transmission, the method comprising, in response to the wireless device determining (S40),during a momentary inactive DRX period that an uplink (UL) transmission is to be initiated by the wireless device, comprising: - (S41) Assess whether the UL transmission can be postponed to a subsequent active DRX period, - in response to determining that the UL transmission can be postponed to a subsequent active DRX period: (S42) Postponing the UL transmission to a subsequent active DRX period, - in response to determining that the UL transmission cannot be postponed to a subsequent active DRX period: (S44) initiating the UL transmission during the current inactive DRX period. [2] The method (40) of claim 1, wherein the MR unit is in a power saving mode at the beginning of the inactive DRX period, and if the wireless device determines during the current inactive DRX period that a UL transmission should be initiated by the wireless device: - the MR unit is maintained in power saving mode in response to determining that the UL transmission can be postponed to a subsequent active DRX period, - the MR unit is transitioned to an active state during the current inactive DRX period in response to determining that the UL transmission cannot be postponed to a subsequent active DRX period. [3] The method (40) of any preceding claim, wherein assessing whether the UL transmission can be postponed to a subsequent active DRX period comprises assessing whether at least one subsequent active DRX period is scheduled to begin within a predetermined time interval. [4] The method (40) of claim 3, wherein different time intervals are each associated with different priority levels, and evaluating whether the UL transmission can be postponed to a subsequent active DRX period comprises: - Determining a priority level associated with the UL transmission to be initiated, - Selecting the time interval associated with the specific priority level. [5] The method (40) of claim 4, wherein the priority level of the UL transmission to be initiated is determined based on a logical channel (LCH) for which the UL transmission is to be initiated. [6] The method (40) of any one of claims 4 to 5, wherein a high priority level is associated with a time interval having a longer duration than a time interval associated with a low priority level. [7] The method (40) of any one of claims 3 to 6, comprising (S45) previously receiving, from the RAN, a time interval configuration for each time interval. [8] The method (40) of claim 7, wherein each time interval configuration is received in system information sent by the RAN and / or in a radio resource control (RRC) message transmitted by the RAN. [9] Method (40) according to one of claims 3 to 8, wherein: - the wireless device comprises 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 method, in response to determining that a plurality of subsequent active DRX periods are scheduled to begin within the time interval, comprises initiating the UL transmission in a subsequent active DRX period selected from the plurality of subsequent active DRX periods based on a wake-up signal detection during the time interval. [10] The method (40) of claim 9, wherein the following active DRX period selected from the plurality of following active DRX periods corresponds to: - the active DRX period immediately following an inactive DRX period within the time interval during which a wake-up signal is detected by the LP-WUR, - or, in response to not detecting a wake-up signal in an inactive DRX period within the time interval: the last following active DRX period of the plurality of following active DRX periods. [11] A wireless device (25) comprising at least one memory and at least one processor configured to perform a method (40) according to any one of the preceding claims. [12] A user equipment (UE) (20) comprising a wireless device according to claim 11. [13] Method (80) for exchanging data in a wireless communication system, wherein the method is implemented by a base station (BS - base station) (30) of a radio access network (RAN - radio access network) of the wireless communication system, wherein the BS is configured to exchange data with a main radio (MR - main radio) unit (253) of a wireless device (25), wherein the BS is configured with a discontinuous reception (DRX) cycle, wherein the DRX cycle includes an active DRX period during which the BS can initiate a downlink (DL) transmission to the MR unit of the wireless device, and an inactive DRX period during which the BS cannot initiate a DL transmission to the MR unit of the wireless device,wherein the method comprises transmitting (S80) a time interval configuration to the wireless device for configuring a time interval in that wireless device, the time interval to be used by the wireless device to determine whether an uplink (UL) transmission to be initiated in an inactive DRX period can be postponed to a subsequent active DRX period., [14] The method (80) of claim 13, wherein the BS transmits to the wireless device different time interval configurations each associated with different priority levels. [15] The method (80) of claim 14, wherein each time interval configuration is transmitted in system information sent by the BS and / or in a radio resource control (RRC) message. [16] Method (80) according to one of claims 13 to 15, wherein: - the wireless device comprises a low-power wake-up receiver (LP-WUR) (254) configured to monitor a wake-up signal transmitted by the BS and, in response to detecting a wake-up signal, to trigger a transition of the MR unit to an active state, - the method, in response to determining that a DL transmission should be initiated by the BS in an active DRX period following a current inactive DRX period, comprises: (S82) transmitting a wake-up signal to the wireless device in the current inactive DRX period. [17] Base station (BS - base station) (30), comprising at least one memory and at least one processor configured to perform a method (80) according to one of claims 13 to 16. [18] A wireless communication system comprising at least one base station (30) according to claim 17 and at least one user device (20) according to claim 12. [19] A computer program product (252, 302) comprising instructions that, when executed by at least one processor, configure the at least one processor to perform a method (40) according to any one of claims 1 to 10 or a method (80) according to any one of claims 13 to 16. [20] A computer-readable storage medium comprising instructions that, when executed by at least one processor, configure the at least one processor to perform a method (40) according to any one of claims 1 to 10 or a method (80) according to any one of claims 13 to 16.

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