Methods, communications devices, and infrastructure equipment

Abstract

A method of operating a communications device comprising a low-power receiver and a main receiver is provided. The method comprises monitoring for receipt of a wake-up signal (WUS) from a wireless communications network within a predefined time window, and triggering, based on receiving the WUS, a receiver of the communications device to monitor for a downlink channel from the wireless communications network during a discontinuous reception (DRX) occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received.

Description

[0001] METHODS, COMMUNICATIONS DEVICES, AND INFRASTRUCTURE EQUIPMENT

[0002] BACKGROUND Field of Disclosure

[0003] The present disclosure relates to communications devices, infrastructure equipment and methods for the more effective power saving of communications devices in wireless communications networks.

[0004] The present application claims the Paris Convention priority from United Kingdom patent application number GB2416442.8, filed on 7 November 2024, the contents of which are hereby incorporated by reference.

[0005] Description of Related Art

[0006] The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.

[0007] Previous generation mobile telecommunication systems, such as those based on the 3GPP defined UMTS and Long Term Evolution (LTE) architecture, are able to support a wider range of services than simple voice and messaging services offered by previous generations of mobile telecommunication systems. For example, with the improved radio interface and enhanced data rates provided by LTE systems, a user is able to enjoy high data rate applications such as mobile video streaming and mobile video conferencing that would previously only have been available via a fixed line data connection. The demand to deploy such networks is therefore strong and the coverage area of these networks, i.e. geographic locations where access to the networks is possible, is expected to continue to increase rapidly.

[0008] Current and future wireless communications networks are expected to routinely and efficiently support communications with an ever-increasing range of devices associated with a wider range of data traffic profiles and types than existing systems are optimised to support. For example, it is expected future wireless communications networks will be expected to efficiently support communications with devices including reduced complexity devices, machine type communication (MTC) devices, high resolution video displays, virtual reality headsets, extended Reality (XR) and so on. Some of these different types of devices may be deployed in very large numbers, for example low complexity devices for supporting the “The Internet of Things”, and may typically be associated with the transmissions of relatively small amounts of data with relatively high latency tolerance. Other types of device, for example supporting high-definition video streaming, may be associated with transmissions of relatively large amounts of data with relatively low latency tolerance. Other types of device, for example used for autonomous vehicle communications and for other critical applications, may be characterised by data that should be transmitted through the network with low latency and high reliability. A single device type might also be associated with different traffic profiles / characteristics depending on the application(s) it is running. For example, different consideration may apply for efficiently supporting data exchange with a smartphone when it is running a video streaming application (high downlink data) as compared to when it is running an Internet browsing application (sporadic uplink and downlink data) or being used for voice communications by an emergency responder in an emergency scenario (data subject to stringent reliability and latency requirements).

[0009] In view of this there is expected to be a desire for current wireless communications networks, for example those which may be referred to as 5G or new radio (NR) systems / new radio access technology (RAT) systems, or indeed future 6G wireless communications, as well as future iterations / releases of existing systems, to efficiently support connectivity for a wide range of devices associated with different applications and different characteristic data traffic profiles and requirements.

[0010] One example of a new service is referred to as Ultra Reliable Low Latency Communications (URLLC) services which, as its name suggests, requires that a data unit or packet be communicated with a high reliability and with a low communications delay. Another example of a new service is extended Reality (XR), which may be provided by various user equipment such as wearable devices. XR combines real- world and virtual environments, incorporating aspects such as augmented reality (AR), mixed reality (MR), and virtual reality (VR), and thus requires high quality and minimised interaction delay. Services such as URLLC and XR therefore represent a challenging example for both LTE type communications systems and 5G / NR communications systems, as well as future generation communications systems.

[0011] 5G NR has continuously evolved and the current work plan includes 5G-NR-advanced in which some further enhancements are expected, especially to support new use-cases / scenarios with higher requirements. The desire to support these new use-cases and scenarios gives rise to new challenges for efficiently handling communications in wireless communications systems that need to be addressed.

[0012] SUMMARY OF THE DISCLOSURE

[0013] The present disclosure can help address or mitigate at least some of the issues discussed above.

[0014] Embodiments of the present technique can provide a method of operating a communications device comprising a low-power receiver and a main receiver. The method comprises monitoring for receipt of a wake-up signal (WUS) from a wireless communications network within a predefined time window, and triggering, based on receiving the WUS, a receiver of the communications device to monitor for a downlink channel from the wireless communications network during a discontinuous reception (DRX) occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received.

[0015] Embodiments of the present technique, which, in addition to methods of operating communications devices, relate to methods of operating infrastructure equipment, communications devices and infrastructure equipment, circuitry for communications devices and infrastructure equipment, computer programs, and computer-readable storage mediums, can allow for the more effective power saving of communications devices operating in a wireless communications network.

[0016] Respective aspects and features of the present disclosure are defined in the appended claims.

[0017] It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the present technology. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019] A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein like reference numerals designate identical or corresponding parts throughout the several views, and wherein:

[0020] Figure 1 schematically represents some aspects of an LTE-type wireless telecommunication system which may be configured to operate in accordance with certain embodiments of the present disclosure; Figure 2 schematically represents some aspects of a new radio access technology (NR) wireless telecommunications system which may be configured to operate in accordance with certain embodiments of the present disclosure;

[0021] Figure 3 is a schematic block diagram of an example infrastructure equipment and communications device which may be configured to operate in accordance with certain embodiments of the present disclosure;

[0022] Figure 4 is a graphical plot of user equipment (UE) processing activity against time illustrating an example of a discontinuous reception (DRX) cycle;

[0023] Figure 5 is a graphical plot of UE processing activity against time illustrating an example of a paging occasion preceded by a wake-up signal (WUS) according to that used for LTE;

[0024] Figure 6 is a graphical plot of UE processing activity against time illustrating an example of a DRX cycle according to that used for 5G / NR;

[0025] Figure 7 illustrates the relationship between a main receiver (MR) and a lower power receiver (LP-WUR) of a UE which may be configured to operate in accordance with certain embodiments of the present disclosure;

[0026] Figure 8 shows an example of how a channel may be monitored for a potential low-power wake-up signal (LP-WUS) by a LP-WUR of a UE prior to a DRX ON duration;

[0027] Figure 9 is reproduced from

[0010] , and illustrates a traffic model for extended Reality (XR);

[0028] Figure 10 shows a part schematic, part message flow diagram representation of a wireless communications system comprising a communications device and an infrastructure equipment in accordance with embodiments of the present technique;

[0029] Figure 11 illustrates an example of how certain parameters (e.g. a starting time) of a DRX ON period may be dependent on when a WUS is received in accordance with embodiments of the present technique; Figures 12A and 12B schematically illustrate examples of how a WUS may comprise a code point indicating how the UE is to interpret the next DRX ON period in accordance with embodiments of the present technique;

[0030] Figure 13 shows a signalling diagram illustrating the signalling between a UE and gNB of various aspects related to embodiments of the present technique; and

[0031] Figure 14 shows a flow diagram illustrating a process of communications in a communications system in accordance with embodiments of the present technique.

[0032] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Long Term Evolution Advanced Radio Access Technology (4G)

[0034] Figure 1 provides a schematic diagram illustrating some basic functionality of a mobile telecommunications network / system 6 operating generally in accordance with LTE principles, but which may also support other radio access technologies, and which may be adapted to implement embodiments of the disclosure as described herein. Various elements of Figure 1 and certain aspects of their respective modes of operation are well-known and defined in the relevant standards administered by the 3GPP (RTM) body, and also described in many books on the subject, for example, Holma H. and Toskala A [1], It will be appreciated that operational aspects of the telecommunications networks discussed herein which are not specifically described (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be implemented in accordance with any known techniques, for example according to the relevant standards and known proposed modifications and additions to the relevant standards.

[0035] The network 6 includes a plurality of base stations 1 connected to a core network 2. Each base station provides a coverage area 3 (i.e. a cell) within which data can be communicated to and from communications devices 4. Although each base station 1 is shown in Figure 1 as a single entity, the skilled person will appreciate that some of the functions of the base station may be carried out by disparate, inter-connected elements, such as antennas (or antennae), remote radio heads, amplifiers, etc. Collectively, one or more base stations may form a radio access network.

[0036] Data is transmitted from base stations 1 to communications devices 4 within their respective coverage areas 3 via a radio downlink (DL). Data is transmitted from communications devices 4 to the base stations 1 via a radio uplink (UL). The core network 2 routes data to and from the communications devices 4 via the respective base stations 1 and provides functions such as authentication, mobility management, charging and so on. Communications devices may also be referred to as mobile stations, user equipment (UEs), user terminals, mobile radios, mobile terminals, terminal devices, wireless transmit and receive units (WTRUs), and so forth. Services provided by the core network 2 may include connectivity to the internet or to external telephony services. The core network 2 may further track the location of the communications devices 4 so that it can efficiently contact (i.e. page) the communications devices 4 for transmitting downlink data towards the communications devices 4.

[0037] Base stations, which are an example of network infrastructure equipment, may also be referred to as transceiver stations, nodeBs, e-nodeBs, eNB, g-nodeBs, gNB and so forth. In this regard different terminology is often associated with different generations of wireless telecommunications systems for elements providing broadly comparable functionality. However, certain embodiments of the disclosure may be equally implemented in different generations of wireless telecommunications systems, and for simplicity certain terminology may be used regardless of the underlying network architecture. That is to say, the use of a specific term in relation to certain example implementations is not intended to indicate these implementations are limited to a certain generation of network that may be most associated with that particular terminology.

[0038] New Radio Access Technology (5G)

[0039] Systems incorporating NR technology are expected to support different services (or types of services), which may be characterised by different requirements for latency, data rate and / or reliability. For example, Enhanced Mobile Broadband (eMBB) services are characterised by high capacity with a requirement to support up to 20 Gb / s. The requirements for Ultra Reliable and Low Latency Communications (URLLC) services are for one transmission of a 32 byte packet to be transmitted from the radio protocol layer 2 / 3 SDU ingress point to the radio protocol layer 2 / 3 SDU egress point of the radio interface within 1 ms with a reliability of 1 - 10"5(99.999 %) or higher (99.9999%) [2],

[0040] Massive Machine Type Communications (mMTC) is another example of a service which may be supported by NR-based communications networks. In addition, systems may be expected to support further enhancements related to Industrial Internet of Things (IIoT) in order to support services with new requirements of high availability, high reliability, low latency, and in some cases, high-accuracy positioning.

[0041] An example configuration of a wireless communications network which uses some of the terminology proposed for and used in NR and 5G is shown in Figure 2. In Figure 2 a plurality of transmission and reception points (TRPs) 10 are connected to distributed control units (DUs) 41, 42 by a connection interface represented as a line 16. Each of the TRPs 10 is arranged to transmit and receive signals via a wireless access interface within a radio frequency bandwidth available to the wireless communications network. Thus, within a range for performing radio communications via the wireless access interface, each of the TRPs 10, forms a cell of the wireless communications network as represented by a circle 12. As such, wireless communications devices 14 which are within a radio communications range provided by the cells 12 can transmit and receive signals to and from the TRPs 10 via the wireless access interface. Each of the distributed units 41, 42 are connected to a central unit (CU) 40 (which may be referred to as a controlling node) via an interface 46. The central unit 40 is then connected to the core network 20 which may contain all other functions required to transmit data for communicating to and from the wireless communications devices and the core network 20 may be connected to other networks 25.

[0042] The elements of the wireless access network shown in Figure 2 may operate in a similar way to corresponding elements of an LTE network as described with regard to the example of Figure 1. It will be appreciated that operational aspects of the telecommunications network represented in Figure 2, and of other networks discussed herein in accordance with embodiments of the disclosure, which are not specifically described (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be implemented in accordance with any known techniques, for example according to currently used approaches for implementing such operational aspects of wireless telecommunications systems, e.g. in accordance with the relevant standards.

[0043] The TRPs 10 of Figure 2 may in part have a corresponding functionality to a base station or eNodeB of an LTE network. Similarly, the communications devices 14 may have a functionality corresponding to the UE devices 4 known for operation with an LTE network. It will be appreciated therefore that operational aspects of a new RAT network (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be different to those known from LTE or other known mobile telecommunications standards. However, it will also be appreciated that each of the core network component, base stations and communications devices of a new RAT network will be functionally similar to, respectively, the core network component, base stations and communications devices of an LTE wireless communications network.

[0044] In terms of broad top-level functionality, the core network 20 connected to the new RAT telecommunications system represented in Figure 2 may be broadly considered to correspond with the core network 2 represented in Figure 1, and the respective central units 40 and their associated distributed units / TRPs 10 may be broadly considered to provide functionality corresponding to the base stations 1 of Figure 1. The term network infrastructure equipment / access node may be used to encompass these elements and more conventional base station type elements of wireless telecommunications systems. Depending on the application at hand the responsibility for scheduling transmissions which are scheduled on the radio interface between the respective distributed units and the communications devices may he with the controlling node / central unit and / or the distributed units / TRPs. A communications device 14 is represented in Figure 2 within the coverage area of the first communication cell 12. This communications device 14 may thus exchange signalling with the first central unit 40 in the first communication cell 12 via one of the distributed units / TRPs 10 associated with the first communication cell 12.

[0045] It will further be appreciated that Figure 2 represents merely one example of a proposed architecture for a new RAT based telecommunications system in which approaches in accordance with the principles described herein may be adopted, and the functionality disclosed herein may also be applied in respect of wireless telecommunications systems having different architectures.

[0046] Thus, certain embodiments of the disclosure as discussed herein may be implemented in wireless telecommunication systems / networks according to various different architectures, such as the example architectures shown in Figures 1 and 2. It will thus be appreciated the specific wireless telecommunications architecture in any given implementation is not of primary significance to the principles described herein. In this regard, certain embodiments of the disclosure may be described generally in the context of communications between network infrastructure equipment / access nodes and a communications device, wherein the specific nature of the network infrastructure equipment / access node and the communications device will depend on the network infrastructure for the implementation at hand. For example, in some scenarios the network infrastructure equipment / access node may comprise a base station, such as an LTE-type base station 1 as shown in Figure 1 which is adapted to provide functionality in accordance with the principles described herein, and in other examples the network infrastructure equipment may comprise a control unit / controlling node 40 and / or a TRP 10 of the kind shown in Figure 2 which is adapted to provide functionality in accordance with the principles described herein.

[0047] A more detailed diagram of some of the components of the network shown in Figure 2 is provided by Figure 3. In Figure 3, a TRP 10 as shown in Figure 2 comprises, as a simplified representation, a wireless transmitter 30, a wireless receiver 32 and a controller or controlling processor 34 which may operate to control the transmitter 30 and the wireless receiver 32 to transmit and receive radio signals to one or more UEs 14 within a cell 12 formed by the TRP 10. As shown in Figure 3, an example UE 14 is shown to include a corresponding transmitter 49, a receiver 48 and a controller 44 which is configured to control the transmitter 49 and the receiver 48 to transmit signals representing uplink data to the wireless communications network via the wireless access interface formed by the TRP 10 and to receive downlink data as signals transmitted by the transmitter 30 and received by the receiver 48 in accordance with the conventional operation.

[0048] The transmitters 30, 49 and the receivers 32, 48 (as well as other transmitters, receivers and transceivers described in relation to examples and embodiments of the present disclosure) may include radio frequency filters and amplifiers as well as signal processing components and devices in order to transmit and receive radio signals in accordance for example with the 5G / NR standard. The controllers 34, 44 (as well as other controllers described in relation to examples and embodiments of the present disclosure) may be, for example, a microprocessor, a CPU, or a dedicated chipset, etc., configured to carry out instructions which are stored on a computer readable medium, such as a non-volatile memory. The processing steps described herein may be carried out by, for example, a microprocessor in conjunction with a random access memory, operating according to instructions stored on a computer readable medium. The transmitters, the receivers and the controllers are schematically shown in Figure 3 as separate elements for ease of representation. However, it will be appreciated that the functionality of these elements can be provided in various different ways, for example using one or more suitably programmed programmable computer(s), or one or more suitably configured application-specific integrated circuit(s) / circuitry / chip(s) / chipset(s). As will be appreciated the infrastructure equipment / TRP / base station as well as the UE / communications device will in general comprise various other elements associated with its operating functionality.

[0049] As shown in Figure 3, the TRP 10 also includes a network interface 50 which connects to the DU 42 via a physical interface 16. The network interface 50 therefore provides a communication link for data and signalling traffic from the TRP 10 via the DU 42 and the CU 40 to the core network 20.

[0050] The interface 46 between the DU 42 and the CU 40 is known as the Fl interface which can be a physical or a logical interface. The Fl interface 46 between CU and DU may operate in accordance with specifications 3GPP TS 38.470 and 3GPP TS 38.473, and may be formed from a fibre optic or other wired or wireless high bandwidth connection. In one example the connection 16 from the TRP 10 to the DU 42 is via fibre optic. The connection between a TRP 10 and the core network 20 can be generally referred to as a backhaul, which comprises the interface 16 from the network interface 50 of the TRP 10 to the DU 42 and the Fl interface 46 from the DU 42 to the CU 40. In order for a UE such as UE 4 or 14 to transmit uplink data to the network (e.g. on a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH)) to, for example, base station 1 or TRP 10, the UE must first ensure it is synchronised with the network on the uplink. Since a particular eNB or gNB expects to be receiving communications from many UEs, it needs to ensure that it shares a common timing understanding with each of these UEs (i.e. they are synchronised in terms of the starting times of frames and Orthogonal Frequency Division Multiplexing (OFDM) symbols). This is so that the eNB is able to schedule communication with each of them in a manner that avoids collisions and to ensure orthogonality of the uplink signals, such that inter-subcarrier interference is avoided or mitigated.

[0051] Power Saving and Discontinuous Reception (DRX) in NR

[0052] In a typical currently deployed network, communications devices can operate in a discontinuous reception (DRX) mode during which the communications devices wake-up (i.e. power-up their receivers) to receive signals during their DRX wake time. DRX operation can occur when the communications devices are in an idle mode or in a connected mode. In connected mode, the communications device is configured to periodically monitor physical downlink control channels (PDCCHs) in groups of slots or subframes. If a PDCCH with a Radio Network Temporary Identifier (RNTI) addressed to the communications device is not detected during the group of slots or subframes, the communications device may sleep for the next cycle of the periodicity. Power saving is an important aspect of a user’s experience of such wireless radio access technologies such as NR, which will influence the adoption of 5G and future generation handsets and / or services. DRX is one method of power saving for NR communications devices.

[0053] In legacy systems such as LTE and NR, a UE in RRC -CONNECTED mode will send a scheduling request when it has UL data to transmit. Following this, the gNB will schedule / allocate some UL transmission resources and inform the UE via DCI on PDCCH where the resources are both in time and frequency and the configuration for the UE’s UL transmission such as MCS, TBS etc. When the UE has no data to transmit in the UL, it waits in RRC-CONNECTED mode. If on the other hand data arrives at the gNB for the UE, the gNB will also schedule DL resources and inform the UE via DCI on PDCCH on the location in frequency and time of the resources and the configuration the UE is to use for DL reception on the allocated resources. Once the UE receives the DL data, it waits in RRC-CONNECTED mode for the next DL data whilst monitoring the PDCCH in every DL subframe for any scheduling information targeted at the UE. The UE battery power consumption whilst in RRC-CONNECTED mode could be quite high because of the continuous PDCCH monitoring by the UE and reception of other DL channels and signals. However, if the network knows that neither DL data for nor UL data from the UE is imminent, it is desirable that the UE goes to sleep while remaining in RRC-CONNECTED mode. In legacy LTE and NR, this entails UE undertaking RRC-CONNECTED mode DRX (C-DRX).

[0054] The basic DRX cycle is shown in Figure 4, which consists of a DRX ON period of duration TDRX-ON and a period of inactivity, i.e. a DRX OFF period, of duration TDRX-OFF where the DRX ON period occurs periodically at a DRX period, PDRX. During the DRX ON period, the UE switches on its receiver to monitor the PDCCH for downlink traffic and switches off its receiver during the DRX OFF period to save power consumption. The DRX parameters TDRX-ON & PDRX are configured by the network.

[0055] The price paid for utilising DRX operation (e.g. C-DRX) is that if data meant for a UE currently in its DRX OFF period arrives at the gNB for delivery to the UE, the gNB can only schedule the data after the DRX OFF period is finished. This latency in data scheduling that arises because of C-DRX can be reduced by initiating a timer, drx-InactivityTimer, immediately after the UE detects a DCI scheduling data to it in one of the PDCCH it monitors during the drx-onDuration intervals of its C-DRX cycle. The effect of this timer is to increase the DRX ON time in anticipation that more data for the UE may arrive at the network. The rationale for this is that if data is being scheduled to the UE now, it is highly likely that more data to the same UE will follow.

[0056] When a UE has no data to transmit and the network has no data for the UE, the UE can transition into RRC-IDLE mode. In legacy systems, there is also RRC-IDLE mode DRX. RRC-IDLE mode DRX is set up to work in conjunction with other RRC-IDLE mode UE procedures such as paging of the UE, tracking area update (TAU) etc. Paging is used by the network to establish mobile terminated connections with the UE. During RRC-IDLE mode the UE can go to sleep to minimise battery power consumption. It is desirable however, for an RRC-IDLE mode UE to wake up regularly and listen for any paging messages that the network may have sent to initiate a mobile terminated connection with the UE or for other established reasons such as TAU. In NR, a UE can also wake up to listen to paging messages in RRC- INACTIVE mode.

[0057] For a UE that is awake, listening for a paging message entails monitoring the PDCCH during configured paging occasions for a DCI Format 1 0 whose cyclic redundancy check (CRC) is scrambled with P- RNTI. For an RRC-IDLE mode UE with which the network is seeking to establish a mobile terminated connection, this DCI carries resource allocation information for a subsequent PDSCH that will carry the actual paging information. If the UE detects the DCI Format 1 0 scrambled with P-RNTI, the UE stays awake to receive the scheduled PDSCH; otherwise, the UE should conclude that it is not being paged and so go back to sleep. The paging information PDSCH carries such information for many targeted UEs. Therefore, the UE needs to decode the PDSCH information to decide whether any of it is meant for the said UE. This is done by determining that some of the information is targeted towards a UE with a network preconfigured UE temporary identity (5G-S-TMSI) that matches the UE’s. The cadence with which the UE wakes up to monitor for paging messages typically follows the RRC-IDLE mode DRX configuration which defines the DRX ON and OFF times in each DRX cycle. Therefore, the network is expected to initiate paging towards a given UE during its DRX ON periods.

[0058] Often, when the UE wakes up to monitor the PDCCH for a DCI Format 1 0 with CRC scrambled with P- RNTI, it would not find it as the UE may not have been paged. Furthermore, even when the UE does find the DCI and then goes on to decode the associated PDSCH, the UE would not find a paging message targeted towards its temporary UE identity. It is only after this that a UE which found the DCI Format 1 0 with CRC scrambled with P-RNTI can conclude that there was no page for it in this paging occasion and go back to sleep. Every time the UE wakes up and does not find a PDCCH scrambled with P-RNTI, the awake UE consumes battery power. Furthermore, every time the UE wakes up, finds a PDCCH scrambled with P-RNTI but does not find a paging message targeted towards its temporary UE identity in the PDSCH, the UE consumes battery power. It should therefore be appreciated by those skilled in the art that such a basic DRX operation may not always be efficient, particularly if a UE frequently does not receive any signals (i.e. any PDCCHs with RNTIs addressed to that UE) during the ON period of the DRX operation. It is therefore desirable to wake the UE up only when there is a paging message actually targeted at the UE in the given paging occasion i.e., when the particular UE is being paged.

[0059] Wake-up Signal (WUS) to Save Power

[0060] There are a number of different ways in which the battery life of a UE may be improved. One such way is by enabling a DRX configuration to adapt to a UE’s expected data reception or transmission profile. For example, a Wake-Up Signal (WUS) may be used to indicate whether a UE should wake up during a DRX ON period. The WUS is a signal or a channel that is transmitted to a UE or a group of UEs prior to a DRX ON period or Paging Occasion (PO) to indicate whether the UE(s) needs to wake up during this ON period and monitor for possible traffic, e.g. monitor the PDCCH. Using a WUS in this way to wakeup a UE recognises that not every DRX ON period contains traffic for the UE, and for such a case, the PDCCH monitoring consumes unnecessary power from the UE, which can be avoided with this WUS signaling. The WUS are typically low complexity signals, e.g., with simple modulation and coding, that can be received by a receiver with lower power consumption than other DL signals or channels, thus resulting in power saving. On the other hand, PDCCH decoding is a power-hungry operation, as it involves such processing as blind decoding. Hence, avoiding PDCCH decoding by detecting WUS signals saves power consumption at the UE.

[0061] Wake-up signals are supported in technologies such as eMTC, NB-IoT and in 5G NR. The eMTC / NB- loT wake-up signal (WUS) is used in RRC-IDLE mode before a paging occasion. If the UE detects a WUS, it wakes up and monitors the following paging occasion for an MTC PDCCH (MPDCCH) or an NB-IoT (NPDCCH) that may further allocate a paging message. If the UE does not receive a WUS, it can go back to sleep. The WUS consists of a known sequence. The UE can monitor for the WUS by performing a correlation against this known sequence. As indicated above, the WUS either can be common to all the UEs associated with the paging occasion, or can be associated with a group of one or more UEs that are associated with the paging occasion.

[0062] An example of a WUS is illustrated by a timing diagram showing a plot of transmission power and UE receiver activity with respect to time provided in Figure 5. As shown in Figure 5, a wake-up signal WUS 51 occurs at a known time offset (i2 - ri) 52 before a paging occasion 54. The time offset 52 allows the UE to “boot-up” its main receiver (MR) after WUS reception and before the paging occasion 54. As a result, the WUS itself can be monitored with a lower power receiver, since the lower power receiver does not need to be able to receive all the features of the signal that the MR is able to receive. The WUS is transmitted prior to the paging occasion 54 as shown in Figure 5 at time n, only when there is an MPDCCH transmission in the paging occasion 54. The MPDCCH transmission in the paging occasion 54 allocates a PDSCH transmission between time , and . The PDSCH transmission comprises paging information such as the Temporary Mobile Subscriber Identity (TMSI) of a UE. The PDSCH transmission allocated by the MPDCCH may be inside or outside the paging occasion 54.

[0063] When the WUS is UE-specific (i.e. each UE has its own WUS), the WUS forthat UE is only sent when there is an MPDCCH in a paging occasion which allocates a PDSCH that is targeted at that UE. When the WUS is group-specific (i.e. a group of UEs share a WUS), the WUS for that group is sent when there is an MPDCCH in a paging occasion which allocates a PDSCH that is targeted to at least one of the UEs in that group. Upon detection of a WUS, the UE will proceed to-fine tune its frequency and timing tracking loops if required and blind detects for an MPDCCH between time 12 and T3 followed by decoding of the PDSCH carrying the paging information between time T3 and . If the UE fails to detect a WUS, it will go back to sleep and skip detecting for MPDDCH. Hence by using WUS, the UE will consume less energy by avoiding unnecessary monitoring of MPDCCH. It should be appreciated that WUS can also be used in connected mode when DRX is used. The paging functionality discussed above has been described with respect to LTE-M / eMTC operation, where the paging PDSCH is allocated using an MPDCCH. Those skilled in the art would appreciate that operation in 5G / NR is similar.

[0064] In some examples, the WUS may be a physical channel containing very little information (e.g. UE ID or a single bit indicating that UEs monitoring that WUS should wake up) and so the UE can decode the WUS very quickly compared with blind decoding for MPDCCH. The WUS can also be encoded with a format that enables low power decoding; for example, the WUS may be a narrow bandwidth signal that can be decoded with low power using a low sampling rate receiver.

[0065] For the example of 5G NR, a wake-up signal WUS is used in CONNECTED mode DRX operation as described in [3], the contents of which are hereby incorporated by reference in their entirety. The 5G NR WUS is based on a PDCCH that carries Downlink Control Information (DCI) format 2 6. The PDCCH may be referred to as Power saving-PDCCH (PS-PDCCH), while the monitoring period for this PDCCH is referred to as a PS-PDCCH monitoring period. Here, the term PS-PDCCH is synonymous with “DCI format 2 6 with CRC scrambled by PS-RNTI”. This monitoring period may also be referred to as a “power saving monitoring period”. The procedure for monitoring DCI format 2 6 is described in detail in section 10.3 of [4], the contents of which are hereby incorporated by reference in their entirety. The NR WUS is described in more detail in [5], the contents of which are hereby incorporated by reference in their entirety.

[0066] An example timing diagram illustrating a transmission of signals with respect to time for a 5G NR operation in CONNECTED mode is shown in Figure 6. As shown in Figure 6, a PS-PDCCH 61 occurs in a search space before a DRX_ON phase 62 of a DRX cycle represented by a double headed arrow 64. This example represents one full CONNECTED mode DRX cycle. A temporal location of the PS- PDCCH 61 is in advance of the DRX ON phase 62 by an amount ps Offset 66. A UE decodes the DCI format 2 6 within the PS-PDCCH. If the DCI indicates that the UE should wake up, the UE wakes up its full receiver circuitry for the next DRX_ON duration 62. Otherwise the UE can go to sleep following the PS-PDCCH and does not have to decode other PDCCH during the DRX ON duration 62. The UE needs to monitor for PS-PDCCH during a monitoring window, where the monitoring window starts at a known time before the start of the DRX_ON period and ends at a time ps_Offset before the start of the next DRX ON period.

[0067] At the time of filing of the present disclosure, 3GPP has completed a study item [6], the contents of which are hereby incorporated by reference in their entirety, on low power receivers and low power wake-up signals for NR-5G.

[0068] At the time of filing of the present disclosure, 3GPP is currently working on the normative phase, in which the objectives are described in [7], The objectives include supporting the 5G NR with LP- WUS / WUR in all RRC states, RRC IDLE / INACTIVE and RRC CONNECTED mode.

[0069] 5G systems are designed and developed targeting for both mobile telephony and vertical use cases. Besides latency, reliability, and availability, UE energy efficiency is also critical to 5G. Currently, 5G devices may have to be recharged per week or day, depending on an individual’s usage time. In general, 5G devices consume tens of milliwatts in RRC idle / inactive state and hundreds of milliwatts in RRC connected state. Designs to prolong battery life therefore are a necessity for improving energy efficiency as well as for providing a better user experience.

[0070] Energy efficiency is even more critical for UEs without a continuous energy source, e.g., UEs using small rechargeable and single coin cell batteries. Among vertical use cases, sensors and actuators are deployed extensively for monitoring, measuring, charging, etc. Generally, their batteries are not rechargeable and are expected to last for at least a few years. Such UEs may be wearable devices which may include smart watches, rings, eHealth related devices, and medical monitoring devices. With typical battery capacities, it is challenging to sustain power for up to one or two weeks as required.

[0071] The power consumption depends on the configured length of wake-up periods, e.g., on the paging cycle. To meet the battery life requirements noted above, eDRX cycles of long durations are expected to be used, resulting in high latency, which is not suitable for services with requirements of both long battery life and low latency. For example, in fire detection and extinguishment use cases, fire shutters should be closed and fire sprinklers should be turned on by the actuators within one or two seconds from the time the fire is detected by sensors; a long eDRX cycle therefore cannot meet the delay requirements. eDRX thus appears not to be suitable for latency-critical use cases. Therefore, the intention is to study ultra-low power mechanisms that can support low latency in Rel-18, e.g. lower than eDRX latency.

[0072] Currently, UEs need to periodically wake up once per DRX cycle, which dominates the power consumption in periods with no signalling or data traffic. If UEs are able to wake up only when they are triggered, e.g. via paging, power consumption could be dramatically reduced. This can be achieved by using a wake-up signal (WUS) - as described above - to trigger the main radio, and a separate receiver at the UE which has the ability to monitor for wake-up signals with ultra-low power consumption without needing to power-up the main radio (MR). The MR is relatively high power consuming, which handles the normal communication with the gNB and works for data transmission and reception, and can be turned off or set to deep sleep when it is not needed to receive data, transmit data or carry out measurements.

[0073] Low Power WUS (LP-WUS)

[0074] The power consumption for monitoring the wake-up signal depends on the wake-up signal design and the hardware module of the wake-up receiver used for wake-up signal detection and processing. The study in [6] was to primarily target low-power WUS and wake-up receiver (WUR) for power-sensitive, small form -factor devices including loT use cases (such as industrial sensors, controllers) and wearable devices. Other use cases are not precluded, e.g. Extended Reality (XR) / smart glasses, smart phones, etc.

[0075] The goal of [6] was hence to support a low power wake up signal (LP-WUS) that is received by a low power wake-up receiver (LP-WUR). While the main receiver (MR) of the UE is asleep, if the LP-WUR detects an LP-WUS in between DRX ON occasions, the MR is woken up by a signal transmitted from the LP-WUR (i.e. a wake-up command), so that the MR can then listen for a paging message in the following paging occasions, and the MR can then subsequently decode any data that is transmitted by the network. Therefore, if the WUS is only transmitted shortly before paging occasions in which the target UE is paged, the MR will be woken up only when an actual paging message targeted at the UE is present in the following paging occasions. This stops the UE MR from waking up to needlessly search for a paging message during paging occasions when the network has not paged the UE, thereby reducing further battery power consumption. A WUS can also be transmitted prior to paging occasions in which the UE is paged for other reasons such as TAU etc.

[0076] Figure 7 shows the relationship between the MR 71 and LP-WUR 72 of a UE. The LP-WUR 72 monitors an LP-WUS occasion (LO) for a signal, RX_sig2, where an LP-WUS is carried by RX_sig2. If the LP- WUR 72 detects an LP-WUS, it wakes up the MR 71 via a wake-up command 73, which may for example be an “ON / OFF” indication. The MR 71 then decodes its input signal, RX_sigl, and receives data 74 which can then be forwarded to the UE’s buffers or processors or the like. In some cases, RX_sig2 is the same as RX_sig 1. For example, RX_sig 1 and RX_sig2 can both exist within the system bandwidth of an NR waveform. In other cases, RX_sigl and RX_sig2 are different. For example, RX sig 1 could be within the system bandwidth of an NR waveform and RX_sig2 could be a narrower bandwidth signal that is in or out of band of the system bandwidth of the NR signal.

[0077] In RRC-IDLE or RRC INACTIVE mode, the LP-WUS can be used to wake up the MR so that the UE can monitor a paging occasion (PO). That is:

[0078] If an LP-WUS is detected, the UE wakes up the MR and the UE decodes the PO; or If an LP-WUS is not detected, the MR is not woken up. Similarly, in RRC-CONNECTED mode, the LP-WUS can be used to wake up the MR so that the UE can monitor for PDCCH during a DRX ON period. That is:

[0079] • If an LP-WUS is detected, the UE wakes up the MR and the UE monitors for PDCCHs during the DRX ON period; or

[0080] • If an LP-WUS is not detected, the MR is not woken up.

[0081] Figure 8 shows the case where an LP-WUS is used to wake up an RRC-CONNECTED mode UE’s MR to monitor for PDCCHs during a DRX ON duration. The UE is configured with connected mode DRX with a certain DRX ON duration and DRX periodicity. The LP-WUR of the UE monitors for an LP-WUS 82 during an LP-WUS occasion (LO) 81 prior to the starting of the next DRX ON duration 83. The UE is aware that if the network were to transmit an LP-WUS 82, it would be transmitted during the LO 81. Hence, the LP-WUR only needs to actively monitor for LP-WUS 82 during the LO 81. There is a minimum T gap from the most recent LO 81 to the start of the next DRX ON duration 83; this gap is needed to start the main radio when an LP-WUS is detected. In the case when there is DL data and the UE is expected to start monitoring for a PDCCH that schedules this DL data in the next DRX ON duration 83, the gNB transmits the LP-WUS signal 82 in the LO 81. If LP-WUS 82 is detected, the LP- WUR wakes the MR up (those skilled in the art would appreciate that this process may take some time, for example up to 100ms). The MR (if not already synchronised) then synchronises to the downlink and monitors for PDCCH during the DRX ON period 83. During the time that the MR wakes up, the MR needs to synchronise with the network and potentially read system information. Vice versa, when there is no DL data, the gNB would not transmit an LP-WUS. This enables the UE will minimize its operation during the next DRX ON period to the LO in which no LP-WUS is received, such as deactivating the main receiver and not having to monitor for PDCCH in the next DRX ON duration (for example, in DRX ON period 84) as no WUS is received during LO 85). This therefore enables a power saving gain to be obtained.

[0082] As those skilled in the art would appreciate, some LP-WUR architectures have sufficiently low power consumption that they can be “ON” all the time. Other LP-WURs have a higher power consumption, or are implemented in UEs which require lower power consumption and / or have less energy storage capacity, and it is therefore advantageous for those LP-WUR to only monitor for LP-WUS in an LP-WUS monitoring window (i.e. in a DRX-like fashion).

[0083] Extended Reality (XR)

[0084] Extended Reality (XR), which covers a number of different types of application such as as augmented reality (AR), mixed reality (MR), and virtual reality (VR), and cloud gaming (CG), refers generally to various types of augmented, virtual, and mixed environments, where human-to-machine and human-to- human communications are performed with the assistance of handheld and wearable end user devices (UEs). XR applications are considered important for NR Rel-18 and beyond (also known as 5G Advanced) [8],

[0085] XR applications may require both a relatively high data rates and low latency. As 5G NR was not designed to support the combination of the aforementioned requirements, XR applications may not be supported optimally in 5G NR networks and user experience may suffer because the required data rate / latency may not be reached and UE power consumption may be high. XR applications may have the unique characteristic that the associated traffic pattern is deterministic (i.e., have a certain periodicity and certain number of traffic flows). There may be further relevant other applications with multiple data streams having different characteristics, like factory automation, remote machine operation, and unmanned aerial vehicle (UAV) operation, or applications requiring a differentiation between video and audio.

[0086] XR traffic is rich in video, especially in the downlink, with a typical frame rate of 60 Hz [9], which leads to a data transmission with non-integer periodicity in NR, i.e. the periodicity is not an integer number of subframes and in this example, the periodicity is 16.67 ms. Due to varying frame encoding delay and network transfer time, the packet arrival at the gNB may experience random jitter. The non-integer and jitter characteristics of XR traffic is known as quasi-periodic traffic. In addition to jitter, the packet size also varies within a range; that is the packet size in each period is random. The jitter and random packet size of UL traffic is illustrated in Figure 9, which is based on a similar figure (figure 5. 1.1-1) in

[0010] ,

[0087] Figure 9 illustrates a single stream traffic model for XR. A first packet 91 is transmitted, representing Internet Protocol (IP) packets belonging to a first video frame. At a later point in time - which, on average, is the inverse of the frame generation rate (i.e., 1 / fps) as denoted by arrow 95 - a second packet 92 is transmitted, representing IP packets belonging to a second video frame. The variable packet size which follows a probability distribution is shown by arrow 93, while the variable jitter which also follows a probability distribution is denoted by arrow 94.

[0088] Technical Problem

[0089] In the above-described WUS operation, a power saving gain can be obtained by only requiring the UE’s receiver (main radio) to monitor for WUS during predefined WUS occasions, and subsequently only monitor DRX ON periods (or paging occasions) if a WUS is received during the corresponding WUS occasion. A further power saving gain can be obtained through use of the above-described UP -WUS operation, by minimizing operation time of the device (main radio) operation when there is no incoming data in the upcoming DRX ON duration, as a separate low-power receiver can be used to monitor for the UP -WUS (or monitoring for the UP -WUS using the main radio, but with a lower power consumption than would be required for monitoring for WUS).

[0090] However, both WUS and UP -WUS operation is still limited in an efficiency sense, in a way that the DRX configuration is static, and the only dynamically controllable aspect of the DRX configuration is that a UE can be controlled to monitor DRX ON periods or not, depending on whether or not the network transmits a WUS. The DRX ON duration is started at a preconfigured time. There is no possibility to start the DRX ON period at different time (e.g., earlier or later). In other examples, there is no possibility to dynamically shorten the DRX ON duration, or change the end time of the DRX ON period. This kind of dynamic behaviour may be needed in some use cases, particularly to adapt to certain traffic types. For example, XR data-traffic, which requires low latency, is typically transmitted in a burst manner and may be affected by jitter as described above with respect to Figure 9. In the case of negative jitter, the device may - in order to ensure that the XR data is aligned with the DRX on period(s) - be required to start the operation of its main radio earlier than the data is received; with fixed durations and start times of main radio operation, the data may not be received in an efficient manner. This dynamic behaviour of traffic types such as XR thus cannot allow for data, with a good power efficiency, be optimally provided by any of the existing solutions as described above.

[0091] In co-pending international patent application with publication number WO 2023 / 160898

[0011] , techniques are proposed for the dynamic adjustment of DRX ON periods in response to the arrival misalignment of XR-type data or the like using new early indication signalling. However, further signalling overheads are introduced through the use of this new early indication signalling, which provides further signals for the UE to monitor for and thus increases power consumption and latency and reduces efficiency. As such, a technical problem to solve is how to enable the dynamic adjustment of DRX ON periods in a manner which addresses the above concerns relating to power consumption, latency, and efficiency. Embodiments of the present technique therefore seek to provide solutions to address such a problem, which exploit the use of wake-up signalling schemes (e.g. WUS, LP-WUS) to enable the dynamic adjustment of DRX ON periods while allowing UEs to reduce power consumption and operate more efficiently.

[0092] Method to Support WUS Operation Indicating Temporarily Adjusted DRX Configuration

[0093] Figure 10 shows a part schematic, part message flow diagram representation of a wireless communications system comprising a communications device (e.g. UE) 101 and an infrastructure equipment (e.g. gNB) 102 in accordance with at least some embodiments of the present technique. The communications device 101 is configured to transmit signals to and / or receive signals from the wireless communications network, for example, to and from the infrastructure equipment 102. Specifically, the communications device 101 may be configured to transmit data to and / or receive data from the wireless communications network (e.g. to / from the infrastructure equipment 102) via a wireless radio interface provided by the wireless communications network (e.g. a Uu interface between the communications device 101 and the Radio Access Network (RAN), which includes the infrastructure equipment 102).

[0094] In the example of Figure 10, the communications device 101 comprises a main receiver (or main receiver circuitry) 101.1, a low-power receiver (or low-power receiver circuitry) 101.2 and at least one controller (or controller circuitry) 101.3, 101.4. Here, a power consumption of the main receiver 101.1 when in use is higher than that of the low-power receiver 101.2 when in use. In other examples of embodiments of the present disclosure however, which are not shown in Figure 10, the communications device 101 may comprise only a single receiver, and no low-power receiver 101.2 such as that shown in the example of Figure 10. The infrastructure equipment 102 comprises a transceiver (or transceiver circuitry) 102.1, and a controller (or controller circuitry) 102.2. Each of the controllers 101.3, 101.4, 102.2 may be, for example, a microprocessor, a CPU, or a dedicated chipset, etc.

[0095] In the example of Figure 10, two controllers 101.3, 101.4 are shown, with a first controller 101.3 operatively coupled to (and hence controlling) the main receiver 101.1, and a second controller 101.4 operatively coupled to (and hence controlling) the low-power receiver 101.2. Those skilled in the art would appreciate that this would be advantageous given that the main CPU (e.g. controller 101.3) of the communications device 101 may be more powerful than a CPU (e.g. controller 101.4) connected to the low-power receiver 101.2 and would consume a lot of power if it needed to be on so as to control the low- power receiver 101.2. Of course, those skilled in the art would appreciate that in some arrangements of embodiments of the present technique - both in which the communications device 101 comprises a single receiver and in which the communications device 101 comprises both a main receiver 101.1 and a low- power receiver 101.2 - the communications device 101 may comprise a single controller (or controller circuitry) used to control either the signal receiver or both of the main receiver 101.1 and the low-power receiver 101.2.

[0096] As shown in the example of Figure 10, the at least one controller 101.3, 101.4 of the communications device 101 is configured to control the communications device 101 to monitor 103 for receipt 104 of a wake-up signal (WUS) from the wireless communications network (e.g. from the infrastructure equipment 102) within a predefined time window, and to trigger 105, based on receiving 104 the WUS, a receiver of the communications device 101 (e.g. the main receiver 101.1) to monitor for a downlink channel 106 (for example, a PDCCH that schedules a PDSCH carrying downlink data at a later time, for example directly a PDSCH carrying downlink data) from the wireless communications network (e.g. from the infrastructure equipment 102) during a discontinuous reception (DRX) occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received 104.

[0097] Here, the communications device 101 may use the low-power receiver 101.2 to monitor 103 for receipt 104 of the WUS, where this WUS may be a low-power WUS (UP -WUS). Alternatively, the communications device 101 may only have a single receiver, which may be used to monitor 103 for receipt 104 of the WUS - which again may be a UP -WUS. Where the single (i.e. main) receiver is used to monitor for an UP -WUS, power saving advantages may still be realised as compared to monitoring for a (non-UP) WUS, as an UP -WUS may be carried by a less complex signal when compared to a (non-UP) WUS. Hence, the UE processes the UP -WUS with a low power consumption.

[0098] Here, the predefined time window - during which the communications device 101 monitors 103 for receipt 104 of the WUS - may be a WUS monitoring occasion (WO) or, in the case of an UP -WUS, a LP- WUS monitoring occasion (LO). In accordance with at least some arrangements of embodiments of the present technique, the WO / LO can be divided into multiple sub-WOs / sub-LOs (sWOs / sLOs) in which each sLO is allocated to the WUS / LP-WUS reception and indicates the associated parameters for the adjusted DRX configuration. That is, the positions within the WO / LO in which the WUS / LP-WUS is received 104 may correspond to different sWOs / sLOs, where each of the sWOs / sLOs is associated with a different parameter / set of parameters (e.g. a different start time) of the next ON period of the configured periodic DRX cycle. Where mention is made below to a WUS, such description should be understood to be equally applicable to an LP-WUS, and vice versa. Similarly, where mention is made below to a WO or sWO, such description should be understood to be equally applicable to an LO or sLO, and vice versa.

[0099] Essentially, embodiments of the present technique therefore propose a method in which a WUS (or LP- WUS) transmission from a gNB to a UE carries information related to potential subsequent action within the same low-power monitoring occasion, which enables the (temporary) change of a current DRX configuration which require the UE to turn its main radio on in advance or with delay e.g. related to a reference configuration.

[0100] Figure 11 illustrates an example of the operation of such embodiments, showing how certain parameters (e.g. a starting time) of a DRX ON period may be dependent on when a WUS is received. Here, a UE is still configured with a legacy DRX operation - i.e. defining a fixed DRX cycle with periodic DRX ON durations with fixed lengths and starting times. This legacy DRX operation (i.e. the fixed, currently configured DRX cycle for a UE) is referred to herein as the reference DRX configuration.

[0101] As can be seen from the example of Figure 11 , prior to each DRX ON occasion, the UE monitors a WU S occasion (WO) or LP-WUS occasion (LO) 111 for receipt of a WUS or LP-WUS 113. Here, the WO / LO may be divided into sub-WOs / LOs (also referred to as sWOs / sLOs) 112 as explained above. In the example of Figure 11, the UE is expecting to receive an LP-WUS 113 in one of a plurality of sLOs 112 of an LO 111, but the skilled person would understand that the example of Figure 11 could similarly apply to monitoring for a WUS in sWOs of a WO. Depending on the sLO 112 in which the LP-WUS 113 is received, the UE is able to determine the parameters of the DRX ON occasion. Since the LP-WUS 113 in the example of Figure 11 is received in the left-most sLO 112, the UE determines that the parameters of the DRX ON occasion (e.g. T offset 115) are such that the DRX ON duration is defined as DRX ON occasion 116, where T offset 115 is defined relative to the reference DRX configuration 117, i.e., the start time of the DRX-ON is advanced by T offset related to the Reference DRX_ON start time Here, a minimum time T gap 114 may be configured such that a DRX ON occasion associated with a particular sWO / sLO is configured to start at least that minimum time T gap 114 from the associated sWO / sLO. Although in the example of Figure 11, the parameter indicated by the sLO 112 in which the LP-WUS 113 is received that defines the associated DRX ON configuration is T offset 115, alternative or additional parameter values (e.g. a duration or a relative end time of the DRX ON occasion) may instead or also be defined as being associated with the possible sLOs.

[0102] In accordance with at least some arrangements of embodiments of the present technique, each DRX occasion (DRX ON) is associated with one sWO and is activated when receiving a WUS within the associated sWO. In more detail, the association of sWO, WUS and DRX ON periods can be configurable. This configuration may be provided either in the existing DRX configuration message (which may be received via RRC signalling) or in a dedicated configuration message. In other words, the communications device may be configured to receive configuration information from the wireless communications network (e.g. from the gNB) before receiving the WUS, wherein the configuration information comprises one or more of: the reference configuration, the time window (i.e. the WO, which may include configured sWOs), and an indication of how parameters (such as the start time) of the next DRX occasion are temporarily adjusted forthat DRX occasion to be dependent on the position (e.g. the time or the sWO) within the time window at which the WUS is received (which may be referred to herein as the new DRX configuration(s)).

[0103] Here, as noted above, the configuration information may be received as higher layer (e.g. RRC) signalling and is specifically provided to the communication device by the network.

[0104] Here, the new DRX configuration(s) may have their own specific parameters, and they may also have common parameters with the reference DRX configuration - in other words, the values of one or more of the parameters associated with at least one of the positions within the time window may be the same as those of the reference DRX configuration, and / or the values of one or more of the parameters associated with at least one of the positions within the time window may be different to those of the reference DRX configuration. For example, the new (i.e. temporarily adjusted) DRX configuration may share all parameters with the reference DRX configuration except for its start time, which may be indicated as the specific parameter T offset as described above.

[0105] In other arrangements of embodiments of the present technique, these configurations may be received separately; i.e. the DRX configuration may be received in accordance with legacy techniques and without changing the current configuration message, while a new configuration message may be defined to update this in accordance with the new DRX configuration of the WO / sWOs and the associated DRX ON period parameters.

[0106] The possible parameter values of the DRX occasion (which depend on the position / sWO in which a WUS is received) that are defined in the configuration message may include any one or more of: the start time of the DRX occasion indicated as an absolute time, the start time of the DRX occasion indicated relative to the reference DRX configuration (i.e. T offset), an absolute end time of the DRX occasion, an end time of the DRX occasion relative to the reference DRX configuration, a duration of the DRX occasion, and an inactivity timer associated with the DRX occasion (i.e. that indicates a time period during which the receiver is to continue to monitor for further downlink channels / signals after receipt of the downlink channel from the network during the DRX ON occasion). Here, the time offset (i.e. T offset) may be indicated as a specified number of symbols, a specified number of slots, a specified number of frames, or the like.

[0107] In accordance with embodiments of the present technique, each sWO can be monitored by the UE for a potential WUS. For instance if the UE detects the WUS in the first allocated sWO - i.e. sLO 113 as shown in the example of Figure 11 - then the UE needs to start the PDCCH monitoring using the main radio in the first DRX occasion (DRX ON) - i.e. DRX ON occasion 116 as shown in the example of Figure 11. Here, in such an example, this basically means the UE turns on its main radio earlier in comparison to the reference DRX (i.e. DRX ON occasion 117 as shown in the example of Figure 11).

[0108] Here, the order of the sWOs - which are disposed in time in advance of the DRX occasion to which they relate - will generally be the same as the order of the new DRX_0N occasion configurations to which they are associated, though it would be appreciated by those skilled in the art that this does not necessarily have to be the case, provided certain requirements (e.g. that a particular sWO / sLO is configured to start at least a minimum time T gap from the associated sWO / sLO) are met. That is, an end of the time window may be arranged earlier in time than an earliest start time of the DRX occasion, and wherein an order in time of the plurality of sWOs is the same as an order in start time of the DRX occasion dependent on the sWOs.

[0109] In accordance with at least some arrangements of embodiments of the present technique, upon the reception WUS in the first sWO, the UE is no longer required to monitor the remaining sWOs as a WUS has already been received. In other words, the communications device is configured to monitor each of the plurality of sWOs in order for reception of the WUS, and to skip monitoring the remaining plurality of sWOs after reception of the WUS.

[0110] While a gNB will generally be able to operate in accordance with embodiments of the present technique as described herein, this is not necessarily true of UEs. Some UEs (such as those more recently deployed into the field) may be able to operate in accordance with the schemes defined by embodiments of the present technique, and explained with reference to the examples of Figures 10 and 11, where activation / selection of the DRX ON period may be based on the location of the sWO / sLO in which a WUS / LP-WUS is received in the time domain. However, other (e.g. legacy or low complexity) UEs may only be configured to operate in accordance with the basic operation as shown in and described above with respect to the example of Figure 8. Other UEs still may be able to operate in accordance with the new schemes according to embodiments of the present technique and with the legacy schemes simultaneously. There may therefore be a requirement for UEs to exchange capability signalling with the network prior to being provided with a DRX configuration.

[0111] Thus, in accordance with at least some arrangements of embodiments of the present technique, a UE may be configured to provide its capability in processing a WUS (or LP-WUS) to the network, as well as indicating whether the UE is able to monitor for WUS / LP-WUS and adjust DRX ON parameters in accordance with the newly defined schemes according to embodiments of the present technique, to operate in accordance with fixed configured DRX ON periods in accordance with the legacy schemes, or both. Such capability signalling may also comprise an indication of the minimum time gap T gap between WUS reception and the DRX ON duration. That is, in other words, the communications device may be configured to transmit, to the wireless communications network (e.g. to the gNB for forwarding to the core network) and before monitoring for the WUS, an indication of capability information associated with the communications device, wherein the capability information indicates a capability of the communications device to monitor for the downlink channel during the DRX occasion when the start time of the DRX occasion is dependent on the position within the time window at which the WUS is received. Such capability information may furthermore indicate a minimum length of time required by the communications device between a first time at which the WUS is received and a second time at which the receiver starts monitoring for the downlink channel.

[0112] In accordance with at least some arrangements of embodiments of the present technique, instead of a position (e.g. time or sWO) in the window at which the WUS is received indicating the DRX ON duration that the UE should monitor for receipt of a PDCCH, the WUS itself may comprise such an indication of the DRX ON duration through a code point included within the WUS. That is, the WUS may comprise an indication that the communications device is to monitor for the downlink channel during the next DRX occasion when the start time of the next DRX occasion is temporarily adjusted such that it is dependent on the position within the time window at which the WUS is received instead of being based on the reference DRX configuration. In accordance with such arrangements of embodiments of the present technique for UEs which may be configured to simultaneously operate in accordance with the new and legacy schemes, the WUS may include one or more different code points indicating whether the UE is to interpret the next DRX ON period in accordance with the new schemes as defined herein or in accordance with the legacy scheme. Here, a code point refers to one bit or one sequence of bits within the WUS, the presence of which within the WUS may mean that the device shall monitor for the PDCCH at a certain adjusted DRX time, while another bit or sequence of bits in the WUS may mean that the PDCCH monitoring shall be done in accordance with the default DRX timing. Thus a WUS can be received at the same time but indicate different DRX timings depending on the content of (i.e. code points included in) the WUS. In another example, a code point can also be uniquely assigned to a UE or a group of UEs. The network, e.g., gNB, can configure the arrangement of such code points.

[0113] Figures 12A and 12B schematically illustrate examples of how a WUS may comprise such a code point or code points, as described in the arrangements above, which indicate how the UE is to interpret the next DRX ON period in accordance with embodiments of the present technique. The examples of Figures 12A and 12B are similar to the example of Figure 11 in terms of the possible DRX ON occasion configurations 116, 117 and the parameters T gap 114 and T offset 115. Figure 12A shows an example where a WUS is received within an sWO 122 of a WO 121, while Figure 12B shows a similar example where an LP-WUS is received within an sLO 126 of an LO 125.

[0114] In the example of Figure 12A, the WUS may comprise two different code points; a first code point 123 and a second code point 124. The code point 124 indicates that the UE is to determine the DRX ON occasion configuration in accordance with the legacy scheme - i.e. this will simply be the currently configured (i.e. reference) DRX ON duration 117 which is affected by the WUS in which it is received. The UE may receive WUS with code point 124 at any time within the entire WO, or only within a separately configured WO length. Most importantly, the WUS carrying code point 124 is not associated with any of the sWOs. The code point 123 on the other hand indicates that the UE is to determine the DRX ON occasion configuration in accordance with arrangements of embodiments of the present technique - i.e. this will be the earliest configured DRX ON duration 116 since the WUS that includes the code point 123is received in the associated earliest configured sWO 122 of the WO 121. Within the entire WO, the UE is expected to receive one WUS. For example, in the first sWO, the UE may receive either a WUS with code point 123 or a WUS with code point 124. If the UE receives a WUS with code point 123 then the UE shall start the DRX ON operation earlier with the T offset from the start time of the reference DRX configuration T reference. If the UE receives a WUS with code point 124 then the UE shall start the DRX ON operation according to the legacy operation; that is at T reference.

[0115] Figure 12B presents a related example to that of Figure 12A, but where an LP-WUS (rather than a WUS) is received in an sLO 126 (rather than sWO) of an LO 125 (rather than a WO). The code point 127 as shown in Figure 12B that may be carried by an LP-WUS corresponds to the code point 123 of Figure 12A, while the code point 128 as shown in Figure 12B that may be carried by an LP-WUS corresponds to the code point 124 of Figure 12A.

[0116] In accordance with at least some arrangements of embodiments of the present technique, each sWO / sLO can contain several monitoring occasions. UEs listening to the same DRX ON can be further sub- grouped and configured to only listen to their associated monitoring occasion within each sWO / sLO. In other words, the communications device may form part of a group of communications devices, the group being one of a plurality of groups each allocated a portion of each of the plurality of sWOs to monitor for reception of the WUS, and wherein the communications device may be further configured to monitor for the WUS during only the portion of each of the plurality of sWOs allocated to the group of which the communications device forms part.

[0117] Figure 13 shows a signalling diagram illustrating the signalling between a UE and gNB of various aspects related to embodiments of the present technique. Such a signalling diagram illustrates all steps from the initial capability exchange and configuration to the receipt of downlink data (i.e. a PDSCH) scheduled by the PDCCH received during the DRX ON period. Those skilled in the art would appreciate that none of the steps of Figure 13 are intended to be either essential to the definition of the invention or not, but are included within the example of Figure 13 so as to present a complete picture of the schemes presented herein so as to enable discussion of various different aspects of embodiments of the present technique.

[0118] In step SI 1, the UE exchanges capability signalling with the gNB, where this capability signalling may be exchanged between the UE and core network (via the gNB) at registration or initial setup, for example. Such capability signalling may, as described above, include an indication of the UE’s capability in processing a WUS (or LP-WUS), as well as indicating whether the UE is able to monitor for WUS / LP- WUS and adjust DRX ON parameters in accordance with the newly defined schemes according to embodiments of the present technique, to operate in accordance with fixed configured DRX ON periods in accordance with the legacy schemes, or both. Such capability signalling may also comprise an indication of the minimum time gap T gap between WUS reception and the DRX ON duration.

[0119] In step S12, the UE receives an RRC configuration message from the gNB, where this RRC configuration message - as noted above - includes the legacy DRX configuration (configuring the reference DRX configuration) as well as an updated DRX configuration (indicating the new parameters for the adjusted DRX occasions) and an updated WUS configuration (indicating the WO and sWOs or LO and sLOs, as well as their association with the new (adjusted) DRX occasions and their parameters). Such a configuration message may be received by the UE at RRC connection step, when the UE is transitioning from RRC IDLE or RRC INACTIVE to RRC CONNECTED. Here, the UE is configured with a single static connected-mode DRX (C-DRX) configuration - i.e. the reference DRX configuration - but the new DRX configuration enables the adjustment of the C-DRX configuration in time. The WUS configuration as noted above may include multiple wake-up occasions (e.g. sLOs or sWOs) which each have a dependency to how the C-DRX configuration is adjusted; i.e. how the UE is to adjust when it starts (and stops) monitoring for PDCCHs during DRX ON periods of the C-DRX cycle.

[0120] In step S13, the UE monitors the newly configured LO or WO window (which may consist as noted above of multiple sLOs or sWOs) for receipt of an LP-WUS or WUS. If no WUS / LP-WUS is received, then the UE refrains from activating PDCCH monitoring, and the receiver (e.g. main radio) of the UE is kept deactivated until the next WO / LO window. Otherwise, processing moves to step S14.

[0121] In step S14, the UE receives the WUS or LP-WUS from the gNB as layer 1 (Ll) / physical (PHY) layer signalling. This WUS / LP-WUS is received within the WO / LO at a certain position (e.g. in a certain sWO / sLO) that indicates a particular new DRX configuration that is associated with that certain position at which the WUS / LP-WUS is received.

[0122] In step S 15, the UE adjusts legacy C-DRX configuration - e.g. the start time of its PDCCH monitoring during the next DRX ON period according to the configured C-DRX cycle. This is, as noted above, based on the reception of the WUS / LP-WUS in a specific position (e.g. sWO / sLO) in the WO / LO. Those skilled in the art would appreciate that, as described above, the start time is only an example of a parameter that the UE may adjust with respect to the configured C-DRX configuration, and that other or additional parameters (such as duration, end time, etc.) may be adjusted. It should also be noted that such adjustment is only temporary, and only valid for the next DRX ON period. The following DRX ON period after that in the C-DRX cycle will depend on the WUS / LP-WUS received prior to that following DRX ON period.

[0123] In step S16, the UE monitors the adjusted DRX ON period for a downlink channel (e.g. PDCCH) from the gNB, where that downlink channel may comprise downlink control information (DCI) carrying a DL grant that schedules a PDSCH carrying data (e.g. XR data) for the UE. The UE may also directly receive the PDSCH carrying data (e.g. XR data) after WUS / LP-WUS detection; for example, when the UE is scheduled with semi-persistent scheduling (SPS). In such a case, the UE monitors the scheduled PDSCH directly in step S17 below and skips step S16.

[0124] In step SI 7, the UE monitors for and receives this scheduled PDSCH. As described above, the steps S16 and S17 may be combined and the UE may directly receive the PDSCH carrying data (e.g. XR data) after WUS / LP-WUS detection.

[0125] Processing then returns back to step S 13 for monitoring of the LO / WO window in the next period of the DRX cycle.

[0126] Figure 14 shows a flow diagram illustrating an example process of communications in a communications system in accordance with embodiments of the present technique. The process shown by Figure 14 is a method of operating a communications device (e.g. UE) comprising a low-power receiver and a main receiver.

[0127] The method begins in step S21. The method comprises, in step S22, monitoring for a potential wake-up signal (WUS) from a wireless communications network (e.g. from a gNB) within a predefined time window. In step S23, the process comprises triggering, based on detecting the target WUS, a receiver of the communications device to monitor for a downlink channel (e.g. a PDCCH) from the wireless communications network (e.g. gNB) during a discontinuous reception (DRX) occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received. The process ends in step S24.

[0128] Those skilled in the art would appreciate that the methods shown by Figures 13 and 14 may be adapted in accordance with embodiments of the present technique. For example, other intermediate steps may be included in (or illustrated steps may be excluded from) such methods, or the steps may be performed in any logical order. Though embodiments of the present technique have been described largely by way of the example communications system shown in Figure 10 and with further reference to Figures 11 and 12, it would be clear to those skilled in the art that they could be equally applied to other systems to those described herein.

[0129] Those skilled in the art would further appreciate that such infrastructure equipment and / or communications devices as herein defined may be further defined in accordance with the various arrangements and embodiments discussed in the preceding paragraphs. It would be further appreciated by those skilled in the art that such infrastructure equipment and communications devices as herein defined and described may form part of communications systems other than those defined by the present disclosure. The following numbered paragraphs provide further example aspects and features of the present technique:

[0130] Paragraph 1. A method of operating a communications device, the method comprising monitoring for receipt of a wake-up signal, WUS, from a wireless communications network within a predefined time window, and triggering, based on receiving the WUS, a receiver of the communications device to monitor for a downlink channel from the wireless communications network during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received.

[0131] Paragraph 2. A method according to Paragraph 1, wherein the receiver is a main receiver and the communications device further comprises a low-power receiver, the low-power receiver being used to monitor for receipt of the WUS.

[0132] Paragraph 3. A method according to Paragraph 1 or Paragraph 2, wherein the WUS is a low-power WUS, UP-WUS.

[0133] Paragraph 4. A method according to any of Paragraphs 1 to 3, wherein the time window is a WUS monitoring occasion, WO, that comprises a plurality of sub-WUS monitoring occasions, sWOs, wherein the start time of the DRX occasion is dependent on which of the plurality of sWOs the WUS is received within.

[0134] Paragraph 5. A method according to Paragraph 4, wherein an end of the time window is arranged earlier in time than an earliest start time of the DRX occasion, and wherein an order in time of the plurality of sWOs is the same as an order in start time of the DRX occasion dependent on the sWOs. Paragraph 6. A method according to Paragraph 5, wherein the communications device is configured to monitor each of the plurality of sWOs in order for reception of the WUS, and wherein the method further comprises monitoring the remaining plurality of sWOs after reception of the WUS.

[0135] Paragraph 7. A method according to any of Paragraphs 4 to 6, wherein the communications device forms part of a group of communications devices, the group being one of a plurality of groups each allocated a portion of each of the plurality of sWOs to monitor for reception of the WUS, and wherein the method further comprises monitoring for the WUS during only the portion of each of the plurality of sWOs allocated to the group of which the communications device forms part.

[0136] Paragraph 8. A method according to any of Paragraphs 1 to 7, comprising transmitting, to the wireless communications network before monitoring for the WUS, an indication of capability information associated with the communications device, wherein the capability information indicates a capability of the communications device to monitor for the downlink channel during the DRX occasion when the start time of the DRX occasion is dependent on the position within the time window at which the WUS is received.

[0137] Paragraph 9. A method according to Paragraph 8, wherein the capability information indicates a minimum length of time required by the communications device between a first time at which the WUS is received and a second time at which the receiver starts monitoring for the downlink channel.

[0138] Paragraph 10. A method according to any of Paragraphs 1 to 9, wherein the position within the time window at which the WUS is received indicates that the start time of the DRX offset is defined by a time offset with respect to a start time of a reference DRX configuration.

[0139] Paragraph 11. A method according to Paragraph 10, wherein the reference DRX configuration is a configuration of the DRX occasion that is currently configured for the communications device before reception of the WUS.

[0140] Paragraph 12. A method according to Paragraph 11, comprising receiving configuration information from the wireless communications network before receiving the WUS, wherein the configuration information comprises one or more of: the reference configuration, the time window, and an indication of how the start time of the DRX occasion is dependent on the position within the time window at which the WUS is received.

[0141] Paragraph 13. A method according to Paragraph 12, wherein the configuration information is received as higher layer signalling and is specifically provided to the communication device.

[0142] Paragraph 14. A method according to Paragraph 12 or Paragraph 13, wherein the indication of how the start time of the DRX occasion is dependent on the position within the time window at which the WUS is received comprises an indication of values of one or more parameters of the DRX occasion associated with each position within the time window, wherein the one or more parameters comprise: the start time of the DRX occasion, the start time of the DRX occasion relative to the reference DRX configuration, an end time of the DRX occasion, an end time of the DRX occasion relative to the reference DRX configuration, a duration of the DRX occasion, and an inactivity timer associated with the DRX occasion that indicates a time period during which the receiver is to remain activated after receipt of the downlink channel from the wireless communications network.

[0143] Paragraph 15. A method according to Paragraph 14, wherein the values of one or more of the parameters associated with at least one of the positions within the time window are the same as those of the reference DRX configuration, and / or the values of one or more of the parameters associated with at least one of the positions within the time window are different to those of the reference DRX configuration.

[0144] Paragraph 16. A method according to any of Paragraphs 11 to 15, wherein the WUS comprises an indication that the communications device is to monitor for the downlink channel during the DRX occasion when the start time of the DRX occasion is dependent on the position within the time window at which the WUS is received instead of being based on the reference DRX configuration.

[0145] Paragraph 17. A method according to any of Paragraphs 10 to 16, wherein the time offset is a specified number of symbols, a specified number of slots, or a specified number of frames.

[0146] Paragraph 18. A communications device comprising a receiver, and a controller configured to control the communications device to monitor for receipt of a wake-up signal, WUS, from a wireless communications network within a predefined time window, and to trigger, based on receiving the WUS, the receiver to monitor for a downlink channel from the wireless communications network during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received. Paragraph 19. Circuitry for a communications device comprising receiver circuitry, and controller circuitry configured to control the communications device to monitor for receipt of a wake-up signal, WUS, from a wireless communications network within a predefined time window, and to trigger, based on receiving the WUS, the receiver circuitry to monitor for a downlink channel from the wireless communications network during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received. Paragraph 20. A method of operating an infrastructure equipment forming part of a wireless communications network, the method comprising transmitting, to a communications device, a wake-up signal, WUS, within a predefined time window, wherein, after transmission of the WUS, the infrastructure equipment is able to transmit a downlink channel to the communications device during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is transmitted.

[0147] Paragraph 21. A method according to Paragraph 20, wherein the WU S is a low-power WU S, UP-WU S . Paragraph 22. A method according to Paragraph 20 or Paragraph 21, wherein the time window is a WUS monitoring occasion, WO, that comprises a plurality of sub-WUS monitoring occasions, sWOs, wherein the start time of the DRX occasion is dependent on which of the plurality of sWOs the WUS is transmitted within.

[0148] Paragraph 23. A method according to Paragraph 22, wherein an end of the time window is arranged earlier in time than an earliest start time of the DRX occasion, and wherein an order in time of the plurality of sWOs is the same as an order in start time of the DRX occasion dependent on the sWOs. Paragraph 24. A method according to Paragraph 22 or Paragraph 23, wherein the communications device forms part of a group of communications devices, the group being one of a plurality of groups each allocated a portion of each of the plurality of sWOs to monitor for reception of the WUS.

[0149] Paragraph 25. A method according to any of Paragraphs 20 to 24, comprising receiving, from the communications device before transmitting the WUS, an indication of capability information associated with the communications device, wherein the capability information indicates a capability of the communications device to monitor for the downlink channel during the DRX occasion when the start time of the DRX occasion is dependent on the position within the time window at which the WUS is transmitted.

[0150] Paragraph 26. A method according to Paragraph 25, wherein the capability information indicates a minimum length of time required by the communications device between a first time at which the WUS is transmitted and a second time at which the communications device starts monitoring for the downlink channel.

[0151] Paragraph 27. A method according to any of Paragraphs 20 to 26, wherein the position within the time window at which the WUS is transmitted indicates that the start time of the DRX offset is defined by a time offset with respect to a start time of a reference DRX configuration.

[0152] Paragraph 28. A method according to Paragraph 27, wherein the reference DRX configuration is a configuration of the DRX occasion that is currently configured for the communications device before transmission of the WUS.

[0153] Paragraph 29. A method according to Paragraph 28, comprising transmitting configuration information to the communications device before transmitting the WUS, wherein the configuration information comprises one or more of: the reference configuration, the time window, and an indication of how the start time of the DRX occasion is dependent on the position within the time window at which the WUS is transmitted.

[0154] Paragraph 30. A method according to Paragraph 29, wherein the configuration information is transmitted as higher layer signalling and is specifically provided to the communication device. Paragraph 31. A method according to Paragraph 29 or Paragraph 30, wherein the indication of how the start time of the DRX occasion is dependent on the position within the time window at which the WUS is transmitted comprises an indication of values of one or more parameters of the DRX occasion associated with each position within the time window, wherein the one or more parameters comprise: the start time of the DRX occasion, the start time of the DRX occasion relative to the reference DRX configuration, an end time of the DRX occasion, an end time of the DRX occasion relative to the reference DRX configuration, a duration of the DRX occasion, and an inactivity timer associated with the DRX occasion that indicates a time period during which a receiver of the communications device is to remain activated after receipt of the downlink channel from the infrastructure equipment.

[0155] Paragraph 32. A method according to Paragraph 31, wherein the values of one or more of the parameters associated with at least one of the positions within the time window are the same as those of the reference DRX configuration, and / or the values of one or more of the parameters associated with at least one of the positions within the time window are different to those of the reference DRX configuration.

[0156] Paragraph 33. A method according to any of Paragraphs 28 to 32, wherein the WUS comprises an indication that the communications device is to monitor for the downlink channel during the DRX occasion when the start time of the DRX occasion is dependent on the position within the time window at which the WUS is transmitted instead of being based on the reference DRX configuration.

[0157] Paragraph 34. A method according to any of Paragraphs 27 to 33, wherein the time offset is a specified number of symbols, a specified number of slots, or a specified number of frames.

[0158] Paragraph 35. An infrastructure equipment forming part of a wireless communications network, the infrastructure equipment comprising a transceiver, and a controller configured to control the infrastructure equipment to transmit, to a communications device, a wake-up signal, WUS, within a predefined time window, wherein, after transmission of the WUS, the infrastructure equipment is able to transmit a downlink channel to the communications device during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is transmitted.

[0159] Paragraph 36. Circuitry for an infrastructure equipment forming part of a wireless communications network, the infrastructure equipment comprising transceiver circuitry, and controller circuitry configured to control the infrastructure equipment to transmit, to a communications device, a wake-up signal, WUS, within a predefined time window, wherein, after transmission of the WUS, the infrastructure equipment is able to transmit a downlink channel to the communications device during a DRX occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is transmitted.

[0160] Paragraph 37. A wireless communications system comprising a communications device according to Paragraph 18 and an infrastructure equipment according to Paragraph 35.

[0161] Paragraph 38. A computer program comprising instructions which, when loaded onto a computer, cause the computer to perform a method according to any of Paragraphs 1 to 17 or any of Paragraphs 20 to 34. Paragraph 39. A non-transitory computer-readable storage medium storing a computer program according to Paragraph 38.

[0162] It will be appreciated that the above description for clarity has described embodiments with reference to different functional units, circuitry and / or processors. However, it will be apparent that any suitable distribution of functionality between different functional units, circuitry and / or processors may be used without detracting from the embodiments. Described embodiments may be implemented in any suitable form including hardware, software, firmware or any combination of these. Described embodiments may optionally be implemented at least partly as computer software running on one or more data processors and / or digital signal processors. The elements and components of any embodiment may be physically, functionally and logically implemented in any suitable way. Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the disclosed embodiments may be implemented in a single unit or may be physically and functionally distributed between different units, circuitry and / or processors.

[0163] Although the present disclosure has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognise that various features of the described embodiments may be combined in any manner suitable to implement the technique.

[0164] References

[0165] [1] Holma H. and Toskala A, “LTE for UMTS OFDMA and SC-FDMA based radio access”, John Wiley and Sons, 2009.

[0166] [2] TR 38.913, “3rdGeneration Partnership Project; Technical Specification Group Radio Access Network; Study on Scenarios and Requirements for Next Generation Access Technologies (Release 14)”, 3GPP, vl4.3.0, August 2017.

[0167] [3] Rl-1708311, “Idle Mode Power Efficiency Reduction,” Sierra Wireless, RAN1#89.

[0168] [4] TS 38.213, “Physical layer procedures for control (Release 18)”, 3GPP, vl8.1.0, December 2023.

[0169] [5] TR 38.840, “NR: Study on UE Power Saving (Release 16, vO.1.0)”, 3GPP, November 2018.

[0170] [6] RP -222644, “Revised SID: Study on low-power Wake-up Signal and Receiver for NR”, RANP#97e, September 2022.

[0171] [7] RP-241824, “Revised WID: Low-power Wake-up Signal and Receiver for NR (LP- WUS / WUR)”, RANP#105, September 2024.

[0172] [8] RP -220285, “Revised SID: Study on XR Enhancements for NR”, Nokia, RAN#95e.

[0173] [9] R2-2302309 (TR 38.835), “Study on XR enhancements for NR”, vl.0.2.

[0174]

[0010] TR 38.838, “Study on XR (Extended Reality) Evaluations for NR (Release 17)”, vl7.0.0.

[0175]

[0011] International patent application with publication number WO 2023 / 160898

Claims

CLAIMSWhat is claimed is:

1. A method of operating a communications device, the method comprising monitoring for receipt of a wake-up signal, WUS, from a wireless communications network within a predefined time window, and triggering, based on receiving the WUS, a receiver of the communications device to monitor for a downlink channel from the wireless communications network during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received.

2. A method according to Claim 1, wherein the receiver is a main receiver and the communications device further comprises a low-power receiver, the low-power receiver being used to monitor for receipt of the WUS.

3. A method according to Claim 1, wherein the WUS is a low-power WUS, LP-WUS.

4. A method according to Claim 1, wherein the time window is a WUS monitoring occasion, WO, that comprises a plurality of sub-WUS monitoring occasions, sWOs, wherein the start time of the DRX occasion is dependent on which of the plurality of sWOs the WUS is received within.

5. A method according to Claim 4, wherein an end of the time window is arranged earlier in time than an earliest start time of the DRX occasion, and wherein an order in time of the plurality of sWOs is the same as an order in start time of the DRX occasion dependent on the sWOs.

6. A method according to Claim 5, wherein the communications device is configured to monitor each of the plurality of sWOs in order for reception of the WUS, and wherein the method further comprises skipping monitoring the remaining plurality of sWOs after reception of the WUS.

7. A method according to Claim 4, wherein the communications device forms part of a group of communications devices, the group being one of a plurality of groups each allocated a portion of each of the plurality of sWOs to monitor for reception of the WUS, and wherein the method further comprises monitoring for the WUS during only the portion of each of the plurality of sWOs allocated to the group of which the communications device forms part.

8. A method according to Claim 1, comprising transmitting, to the wireless communications network before monitoring for the WUS, an indication of capability information associated with the communications device, wherein the capability information indicates a capability of the communications device to monitor for the downlink channel during the DRX occasion when the start time of the DRX occasion is dependent on the position within the time window at which the WUS is received.

9. A method according to Claim 8, wherein the capability information indicates a minimum length of time required by the communications device between a first time at which the WUS is received and a second time at which the receiver starts monitoring for the downlink channel.

10. A method according to Claim 1, wherein the position within the time window at which the WUS is received indicates that the start time of the DRX offset is defined by a time offset with respect to a start time of a reference DRX configuration.

11. A method according to Claim 10, wherein the reference DRX configuration is a configuration of the DRX occasion that is currently configured for the communications device before reception of the WUS.

12. A method according to Claim 11, comprising receiving configuration information from the wireless communications network before receiving the WUS, wherein the configuration information comprises one or more of: the reference configuration, the time window, and an indication of how the start time of the DRX occasion is dependent on the position within the time window at which the WUS is received.

13. A method according to Claim 12, wherein the configuration information is received as higher layer signalling and is specifically provided to the communication device.

14. A method according to Claim 12, wherein the indication of how the start time of the DRX occasion is dependent on the position within the time window at which the WUS is received comprises an indication of values of one or more parameters of the DRX occasion associated with each position within the time window, wherein the one or more parameters comprise: the start time of the DRX occasion, the start time of the DRX occasion relative to the reference DRX configuration, an end time of the DRX occasion, an end time of the DRX occasion relative to the reference DRX configuration, a duration of the DRX occasion, and an inactivity timer associated with the DRX occasion that indicates a time period during which the receiver is to remain activated after receipt of the downlink channel from the wireless communications network.

15. A method according to Claim 14, wherein the values of one or more of the parameters associated with at least one of the positions within the time window are the same as those of the reference DRX configuration, and / or the values of one or more of the parameters associated with at least one of the positions within the time window are different to those of the reference DRX configuration.

16. A method according to Claim 11, wherein the WUS comprises an indication that the communications device is to monitor for the downlink channel during the DRX occasion when the start time of the DRX occasion is dependent on the position within the time window at which the WUS is received instead of being based on the reference DRX configuration.

17. A method according to Claim 10, wherein the time offset is a specified number of symbols, a specified number of slots, or a specified number of frames.

18. A communications device comprising a receiver, and a controller configured to control the communications deviceto monitor for receipt of a wake-up signal, WUS, from a wireless communications network within a predefined time window, and to trigger, based on receiving the WUS, the receiver to monitor for a downlink channel from the wireless communications network during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received.

19. Circuitry for a communications device comprising receiver circuitry, and controller circuitry configured to control the communications device to monitor for receipt of a wake-up signal, WUS, from a wireless communications network within a predefined time window, and to trigger, based on receiving the WUS, the receiver circuitry to monitor for a downlink channel from the wireless communications network during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is received.

20. A method of operating an infrastructure equipment forming part of a wireless communications network, the method comprising transmitting, to a communications device, a wake-up signal, WUS, within a predefined time window, wherein, after transmission of the WUS, the infrastructure equipment is able to transmit a downlink channel to the communications device during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is transmitted.

21. An infrastructure equipment forming part of a wireless communications network, the infrastructure equipment comprising a transceiver, and a controller configured to control the infrastructure equipment to transmit, to a communications device, a wake-up signal, WUS, within a predefined time window, wherein, after transmission of the WUS, the infrastructure equipment is able to transmit a downlink channel to the communications device during a discontinuous reception, DRX, occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is transmitted.

22. Circuitry for an infrastructure equipment forming part of a wireless communications network, the infrastructure equipment comprising transceiver circuitry, and controller circuitry configured to control the infrastructure equipment to transmit, to a communications device, a wake-up signal, WUS, within a predefined time window, wherein, after transmission of the WUS, the infrastructure equipment is able to transmit a downlink channel to the communications device during a DRX occasion, wherein a start time of the DRX occasion is dependent on a position within the time window at which the WUS is transmitted.

23. A wireless communications system comprising a communications device according to Claim 18 and an infrastructure equipment according to Claim 21.

24. A computer program comprising instructions which, when loaded onto a computer, cause the computer to perform a method according to Claim 1 or Claim 20.

25. A non-transitory computer-readable storage medium storing a computer program according to Claim 24.

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