Methods, communications devices, and infrastructure equipment

Abstract

Methods, communications devices and infrastructure equipment for allowing a communications device to identify configuration information for a low-power wake up signal to be monitored for by a low-power receiver of the communications device. The configuration information is available to the UE during RRC idle mode, and based on the configuration information, the low-power receiver monitors for the low-power wake up signal.

Description

[0001] METHODS, COMMUNICATIONS DEVICES, AND INFRASTRUCTURE EQUIPMENT

[0002] The present application claims the Paris Convention priority of European patent application EP23185615.4, filed 14 July 2023, the contents of which are hereby incorporated by reference.

[0003] BACKGROUND

[0004] Field of Disclosure

[0005] The present disclosure relates to communications devices, infrastructure equipment and methods for the more effective power saving of communications devices in wireless communications networks.

[0006] Description of Related Art

[0007] 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.

[0008] 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.

[0009] 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 I 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). 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 I new radio access technology (RAT) systems, or indeed future 6G wireless communications, as well as future iterations I 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 enhanced Mobile Broadband (eMBB) services, which are characterised by a high capacity with a requirement to support up to 20 Gb / s. URLLC and eMBB type services therefore represent challenging examples for both LTE type communications systems and 5G / NR 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] According to a first aspect, there is provided a method of operating a communications device comprising a low-power receiver and a main receiver, wherein the communications device is configured to transmit signals to and / or to receive signals from an infrastructure equipment of a wireless communications network via a wireless radio interface provided by the wireless communications network, the method comprising: identifying configuration information for a low-power wake-up signal, LP-WUS; and based on the identified configuration information, monitoring for the LP-WUS using the low-power receiver while the low-power receiver is in an on state and the main receiver is in an off state.

[0015] According to a second aspect, there is provided a method of operating an infrastructure equipment of a wireless communications network, wherein the infrastructure equipment is configured to transmit signals to and / or to receive signals from a communications device via a wireless radio interface provided by the wireless communications network, the method comprising: transmitting, to the communications device, a low-power wake-up signal, LP- WUS, in accordance with configuration information defined for the LP-WUS.

[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;

[0021] 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;

[0022] 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;

[0023] Figure 4 is a graphical plot of user equipment (UE) processing activity against time illustrating an example of a discontinuous reception (DRX) cycle;

[0024] 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 according to that used for LTE;

[0025] 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;

[0026] 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;

[0027] Figure 8 shows an example of how a low-power wake-up signal (LP-WUS) may be monitored for by an LP-WUR of a UE prior to a paging occasion;

[0028] Figure 9 illustrates an example of a low-power WUS and a number of parameters for the low- power WUS that may be indicated by configuration information for the low-power WUS.

[0029] Figure 10 illustrates a method of operating a communications device according to an example of the present disclosure.

[0030] Figure 11 illustrates a method of operating an infrastructure equipment according to an example of the present disclosure.

[0031] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Long Term Evolution Advanced Radio Access Technology (4G)

[0033] 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. 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.

[0034] Data is transmitted from base stations 1 to communications devices or mobile terminals (MT) 4 within their respective coverage areas 3 via a radio downlink. Data is transmitted from communications devices 4 to the base stations 1 via a radio uplink. 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. The communications or terminal devices 4 may also be referred to as mobile stations, user equipment (UE), user terminal, mobile radio, communications device, 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.

[0035] 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.

[0036] New Radio Access Technology (5G (NR))

[0037] 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 (Dlls) 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.

[0038] 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.

[0039] 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.

[0040] 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 I TRPs 10 may be broadly considered to provide functionality corresponding to the base stations 1 of Figure 1 . The term network infrastructure equipment I 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 lie with the controlling node I central unit and I or the distributed units I 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 I TRPs 10 associated with the first communication cell 12.

[0041] 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.

[0042] Thus, certain embodiments of the disclosure as discussed herein may be implemented in wireless telecommunication systems I 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 I access nodes and a communications device, wherein the specific nature of the network infrastructure equipment I 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 I 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.

[0043] 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 circuit 49, a receiver circuit 48 and a controller circuit 44 which is configured to control the transmitter circuit 49 and the receiver circuit 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 circuit 30 and received by the receiver circuit 48 in accordance with the conventional operation.

[0044] The transmitter circuits 30, 49 and the receiver circuits 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 controller circuits 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) I circuitry I chip(s) I chipset(s). As will be appreciated the infrastructure equipment I TRP I base station as well as the UE I communications device will in general comprise various other elements associated with its operating functionality.

[0045] 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.

[0046] The interface 46 between the DU 42 and the CU 40 is known as the F1 interface which can be a physical or a logical interface. The F1 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 TRP10 to the DU 42 and the F1 interface 46 from the DU 42 to the CU 40.

[0047] Power Saving and Discontinuous Reception (DRX) in NR

[0048] 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.

[0049] 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 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. It should be appreciated by those skilled in the art that such a basic operation may not always be efficient, particularly if a UE frequently does not receive any RNTI addressed to it during the ON period (or active operating mode) of the DRX operation.

[0050] Wake-up Signals to Save Power

[0051] 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 signal in this way to wake-up 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.

[0052] Wake-up signals are supported in technologies such as eMTC, NB-loT and in 5G NR. The eMTC I NB-loT wake-up signal (WUS) is used in 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-loT (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 UEs that are associated with the paging occasion.

[0053] 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 T2 - TI 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. 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 TI , only when there is an MPDCCH transmission in that paging occasion. When the WUS is UE-specific (i.e. each UE has its own WUS), the WUS for that UE is only sent when there is an MPDCCH transmission in that paging occasion 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 only when there is an MPDCCH in that paging occasion 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 T2 and T3 followed by decoding of the PDSCH carrying the paging message between time T3 and T4. 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. Paging functionality has been described above with respect to LTE-M I eMTC operation, where the paging PDSCH is allocated using an MPDCCH. Operation in 5G I NR is similar, as will be appreciated by a skilled artisan.

[0054] 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.

[0055] For the example of 5G NR, a wake-up signal WUS is used in CONNECTED mode DRX operation [3], The 5G NR WUS is based on a PDCCH that carries Downlink Control Information (DCI). 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 “PDCCH that is scrambled with a PS-RNTI”. This monitoring period may also be referred to as a “power saving monitoring period”. The NR WUS is described in more detail in [4],

[0056] An example timing diagram illustrating a transmission of signals with respect to time for a 5G NR operation in a 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 within the PS-PDCCH. Since the UE only has to decode the PS-PDCCH, it does not have to operate its full receiver circuitry, and therefore PS-PDCCH can be decoded with a lower receive power. 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 DRX_ON period.

[0057] At the time of filing of the present disclosure, 3GPP has started a study item [5] on low power receivers and low power wake-up signals for NR-5G. The justification of this study, as described in section 3 of [5], is reproduced below.

[0058] 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. 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.

[0059] 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.

[0060] 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 works for data transmission and reception, and can be turned off or set to deep sleep unless it is turned on.

[0061] The power consumption for monitoring 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 [5] is 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. The goal is hence to support a low power wake up signal (LP-WUS) that is received by a low power wake-up receiver (LP-WUR). If the LP-WUR detects an LP-WUS, the main receiver (MR) of the UE is woken up and the MR can then decode the data that is transmitted by the network. Figure 7 shows the relationship between the MR 71 and LP-WUR 72 of a UE.

[0062] The LP-WUR 72 receives a signal, RX_sig2, and monitors for LP-WUS within RX_sig2. If the LP-WUR 72 detects an LP-WUS, it wakes up the MR 71 via, for example an “ON I OFF” indication 73. The MR 71 then decodes its input signal, RX_sig1 , 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_sig1. For example, RX_sig1 and RX_sig2 can refer to the system bandwidth of an NR waveform. In other cases, RX_sig1 and RX_sig2 are different. For example, RX_sig1 could be the system bandwidth of an NR waveform and RX_sig2 could be a narrower bandwidth that is an in or out of band signal.

[0063] In IDLE mode, the LP-WUS could be used to wake up the MR so that the UE can monitor a paging occasion (PO). That is:

[0064] • If an LP-WUS is detected, the UE wakes up MR and the UE decodes the PO; or

[0065] • If an LP-WUS is not detected, the MR is not woken up. Figure 8 shows the case where an LP-WLIS 81 is used to wake an IDLE mode UE up to monitor for a paging message during a paging occasion (PO). The LP-WLIR of the UE monitors for an LP-WUS 81 during an LP-WUS monitoring window. The LP-WUR of the UE knows that if the network were to transmit an LP-WUS 81 , it would be transmitted during the LP-WUS monitoring window. Hence, the LP-WUR only needs to actively monitor for LP-WUS 81 during this LP-WUS monitoring window. If LP-WUS 81 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 100ms). The MR then synchronises to the downlink and monitors for PDCCH 82 during the paging occasion. If the UE receives a PDSCH 83 containing its identifier during the PO, the UE performs an initial access procedure with the network. During the time that the MR wakes up, the MR needs to synchronise with the network and potentially read system information. It should be appreciated here that if an LP-WUS is not detected, the LP-WUR does not need to wake up the MR.

[0066] 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 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). However, in order for an LP-WUR to do so, the properties of the LP-WUS must be known in advance.

[0067] That is, for an LP-WUS that is transmitted either in-band (using frequencies within the bandwidth of the component carrier being currently used for downlink transmissions to the UE) or out-of-band (not using frequencies within the bandwidth of the component carrier being currently used for downlink transmissions to the UE), the receiving UE may need to know configuration information for the WUS, which may include: the waveform structure and characteristics (e.g. bandwidth, and contents) of the WUS, the start and end times (or the start time and duration) of the WUS, a number of repetitions of the WUS, and the frequency resources used for transmitting the WUS or its start frequency and bandwidth. Furthermore, this configuration information should be available for the UE during RRC idle mode.

[0068] As such, according to the present disclosure, a UE may identify configuration information associated with a LP-WUS, and based on the identified configuration information, monitoring for the LP-WUS using the low-power receiver while the low-power receiver is in an on state and the main receiver is in an off state. The configuration information may include one or more parameters. Such parameters may include, for example, a frequency range for the LP-WUS, a start time of the LP-WUS, a duration of the LP-WUS, a waveform structure of the LP-WUS, a cell identifier of a cell on which the LP-WUS is transmitted, a number of repetitions of the LP-WUS, and / or a periodicity of occurrence of the LP-WUS.

[0069] In some examples, configuration information for the WUS may be broadcast to all UEs in a cell by a base station, e.g. via a system information broadcast (SIB). In this way, all UEs that have obtained downlink synchronisation may also receive the configuration information for the WUS. UEs in RRC idle mode may obtain the configuration information in multiple ways. For example, a UE in RRC connected mode may save the WUS configuration information acquired from reading the relevant SIBs before the UE transitions into RRC idle mode. In some cases the UE may request the relevant SIBs via RRC requests. In other examples, a UE may read an SIB using its main receiver in RRC idle mode and, after saving the WUS configuration information, remain in RRC idle mode but power down its main receiver and maintain / activate its low power receiver in an on state. In other examples, an RRC idle mode UE may periodically wake up its main receiver, acquire the system information and the SIBs carrying the WUS configuration information, which the UE may store before returning to RRC idle mode. Furthermore, in some cases the UE may obtain the WUS configuration information via RRC signalling (either unicast or broadcast), or MAC CE signalling from a base station when the UE is in RRC connected mode. The configuration information (or one or more parameters of the configuration information) may also be defined in the specifications (i.e. predefined). Furthermore, one or more parameters of the WUS configuration information may be included in a SIB, one or more components of the WUS configuration information may be included in RRC or MAC CE signalling, and one or more parameters of the WUS configuration information may be defined in the specifications.

[0070] In some examples, the LP-WUR during RRC idle mode may be used to determine which cell to monitor paging from. This can be done by measuring the power (e.g. received signal strength indicator (RSSI), reference signal received power (RSRP), or reference signal received quality (RSRQ)) of the different WUS signals transmitted from each of the cells in proximity to its current cells. In this case, the UE identifies WUS configuration information for all the neighbouring cells. In this case, the LP-WUS configuration information may also indicate the identity of the cell which transmits the LP-WUS. This allows the UE to perform LP- WUS measurements on different cells by using the appropriate LP-WUS configuration. It should also be noted, that the cell ID of the cell on which an LP-WUS is transmitted may be included in the configuration information in other examples where only a single cell is available to a UE.

[0071] The WUS configuration information may include an indication of the frequency resources occupied by the LP-WUS. In particular, the UE may need to know both the starting frequency and the bandwidth of the WUS for both an in-band and out-of-band WUS, and these may be indicated in a number of different ways.

[0072] For example, the frequency resources may be indicated using an absolute radio frequency (ARF) associated with a particular frequency of the WUS, and a bandwidth. The particular frequency of the WUS may be the middle frequency of the WUS, the lowest frequency of the WUS, or the highest frequency of the WUS. The particular frequency of the WUS may, for example, be designated by an absolute radio frequency number (ARFN) plus an offset from the centre frequency of the ARFN. This may be particularly useful if the WUS is carried in a channel ised / rasterized part of the frequency spectrum. The ARF can be represented by the EARFCN (E-UTRA Absolute Radio Frequency Channel Number), as defined in 3GPP specification 38.101 section 5.7.3 [6], The EARFCN identifies both the carrier frequency and the band. The EARFCN hence unambiguously defines the location of the LP-WUS in the frequency spectrum. This example of using an ARF to identify the frequency resources for the WUS may be used for both an in-band and out-of-band WUS.

[0073] For an in-band WUS, the frequency resources occupied can be designated by the index of the first resource element (RE) and the bandwidth designated as the number of REs occupied. As another example, the occupied frequency resources may be designated in resource blocks (RB), and as such the start frequency may be designated as the index of the first RB occupied whilst the bandwidth is designated as the number of RBs occupied by the WUS. In cases in which the WUS bandwidth incorporates a non-integer number of RBs, the start frequency may be designated as an RB index plus an RE offset, and the bandwidth may be designated as an integer number of RBs plus a number of REs. In some cases, any of the ARF, ARFN, index of the first RE, index of the first RB, the absolute bandwidth, the number of REs and / or the number of RBs occupied may be predefined in specifications.

[0074] As discussed above, the occupied frequency resources may be indicated by absolute frequencies or resource elements / blocks, however in some cases the occupied frequency resources may be occupied relative to an already-configured bandwidth part (BWP). For example, the starting RE or RB index of the WUS may be indicated relative to the downlink (DL) BWP starting RE or RB index in which the WUS occurs. As the configuration of the BWP in which the WUS occurs is already available to the UE in existing implementation, the UE is therefore able to calculate the frequency resources occupied by the WUS. In this case, configuration information for the WUS may include an index for the BWP, a BWP-offset frequency relative to the start of the BWP in which the WUS occurs and the WUS bandwidth information.

[0075] This example is illustrated in Figure 9, where a UE’s DL bandwidth 910 is divided into 4 BWPs 912: BWPs 912A-D. Here, the configuration information for a WUS 920 indicates an index for BWP 912B in which the WUS 920 exists, an offset 924 for the lowest (or middle or highest) frequency of BWP 912B, and a bandwidth 922 for the WUS 920. In some examples, the BWP 912 in which the WUS 920 occurs may be predefined in the specifications. For example, when the UE is in RRC-idle mode, the BWP of the WUS occurrence may be the Initial BWP or a different, default BWP. If the BWP containing the WUS is the Initial BWP, the WUS configuration information can be included in configuration information for the initial BWP.

[0076] In RRC-connected and RRC-inactive modes, the BWP of the WUS may be the current active BWP. That is, the BWP of the WUS may be the BWP that is currently active for a UE to receive DL signals. Alternatively, in RRC-connected and RRC-inactive modes, the WUS can be configured in a separate DL BWP that is different to the active BWP of the UE. The DL BWP occupied by the WUS may also have a different configuration to the active BWP of the UE. For example, the BWP occupied by the WUS may be configured in a way that allows for low power decoding of the BWP (e.g. the BWP could be associated with fewer transmit antenna ports, allowing decoding with less channel estimation; or the BWP could be configured with signals transmitted at a lower MCS (modulation and coding scheme), allowing for decoding of the BWP’s signals with less accuracy while still allowing for reliable decoding). Configuring a separate BWP for the WUS would allow different BWPs to share the same WUS BWP.

[0077] In RRC-IDLE mode, a UE normally monitors the Initial BWP of the cell. In some examples, this initial BWP may contain the LP-WUS. In other examples, in RRC-IDLE mode, UEs in a cell may be configured with two BWPs. A first BWP may be the Initial BWP. The second BWP may be a BWP that contains the WUS. This second BWP can be configured differently to the first BWP (for example, the switching time between the second BWP and the first BWP can be different to the switching time between the initial BWP and another BWP). The second BWP may be the same as the BWP used for carrying WUS in RRC-connected I RRC-inactive modes. This allows the system to use a single BWP to transmit WUS to both RRC-connected / RRC-inactive mode UEs and RRC-idle mode UEs.

[0078] In some examples, the second BWP may be configured via a SIB that is transmitted in the first BWP. In other examples, the second BWP may be configured via unicast signalling in RRC-connected mode. In this case, the UE may decode a SIB in the initial BWP and if the UE determines that it will monitor for the WUS, the UE may initiate an RRC connection. In the RRC connection, the UE may request an LP-WLIS configuration. The UE may then receive its LP-WLIS configuration. In some cases, this LP-WLIS configuration may contain UE-specific information (for example, assigning different UEs to different LP-WLIS configurations).

[0079] Furthermore, in some examples, the second BWP may be in a known frequency location (for example, through standardisation or via a configuration parameter that is stored on the UE’s SIM). The UE may monitor for the LP-WUS in that second BWP. If the UE detects an LP-WUS in the second BWP, the UE may attempt to decode the first BWP. This allows a UE to detect cells in a low power manner, without having to go through the more power hungry approach of decoding PSS I SSS / SIB in the initial BWP. Initial BWP decoding may in some cases only be initiated if the presence of LP-WUS indicates that there is an active cell.

[0080] If LP-WUS for more than one cell are configured to use the same time and frequency resources either in-band or out of band of any of the component carriers of the more than one cell, then the LP-WUS of the more than one cells have to be orthogonal to each other. Such orthogonality may be ensured e.g., either by separating the LP-WUS in frequency and / or time and / or code.

[0081] BWPs such as those described above may be configured via a BWP configuration message. Such a BWP configuration message may indicate frequency resources of the BWP. Furthermore, the BWP configuration may also contain information on MIMO configurations or power saving parameters (such as cross-slot scheduling parameters). According to the present disclosure, the LP-WUS configuration can be included as part of the BWP configuration. This allows the LP-WUS configuration to be different between BWPs. For example, the LP-WUS configuration can change between BWPs in terms of:

[0082] Location in frequency domain;

[0083] Location in time domain. For example, the time offset between the LP-WUS and the start of a DRX cycle (or paging monitoring occasion in IDLE mode) can change between BWPs;

[0084] Number of repetitions. The number of repetitions of the LP-WUS can be different between BWPs. This would allow different BWPs to support different coverage levels for the LP-WUS;

[0085] Waveform. Different BWPs can support different LP-WUS waveforms. For example, one BWP could support an on-off keying (OOK) waveform that supports transmission of 1 bit per OFDM symbol, whereas a second BWP could support an OOK waveform that supports transmission of 2 bits per OFDM symbol;

[0086] In addition or alternatively to an indication of the frequency resources occupied by the WUS, the configuration information for the WUS may also include the time at which the WUS occurs. As shown in Figure 9, this may include the start time 926 of the WUS, and the duration 928 of the WUS.

[0087] The time at which the WUS signal starts may in some cases be configured in two parts: subframe index and an offset from the start of subframe in slots, OFDM symbols, or clock cycles. If the time offset is in slots or OFDM symbols, then the subcarrier spacing used can be that for the WUS itself or the SOS for the BWP in which the WUS signal occurs. In some examples, the time at which the WUS starts can be discerned from the configuration of the DRX. That is, since the WUS will usually occur shortly before a DRX ON time (see Figures 5 and 8) the start time 926 may be indicated as a time offset between a start of the DRX ON time and a start of the WUS. This time offset can be defined in subframes, slots, OFDM symbols, or clock cycles. If the time advance is in slots or OFDM symbols, then the subcarrier spacing used for the OFDM symbols can be that used for the WUS signal itself or the SOS configured for the BWP in which the WUS signal occurs.

[0088] Furthermore, the time duration of the WUS may be configured in OFDM symbols or number of subframes. If configured in OFDM symbols, then the subcarrier spacing used can be that for the WUS itself or the SOS configured for the BWP in which the WUS occurs. In some cases, both the time offset with respect to the DRX ON time, the duration of the WUS and the number of repetitions may be known to the UE and gNB in advance (e.g. predefined in the specifications).

[0089] In addition, or alternatively to an indication of the frequency resources occupied by the WUS and the time at which it occurs and lasts, the configuration information for the WUS may also include the periodicity of occurrence in time of the WUS. This periodicity may be expressed in subframes, slots and / or OFDM symbols. When the time of occurrence of the WUS is configured as an offset from the DRX-ON time of the DRX configuration (or as an offset from the start of the paging occasion), the periodicity of occurrence of the LP-WUS can be the same as that of DRX-ON I paging occasion.

[0090] In addition or as an alternative to the frequency resources and timing, the configuration information for the WUS may include other characteristics that the LP-WUR receiver may need to know to successfully detect and decode the WUS. This is especially the case if the specification has more than one WUS waveform specified. Characteristics that may be indicated in the configuration information include waveform type, subcarrier spacing, and (for a WUS that also carries data) how much data is carried and the form of modulation used. If carried data is coded, the coding rate may also be configured. Some WUS signals may also be repeated, for example for coverage enhancement. In this case, the WUS characteristics may also include a number of repetitions of the WUS.

[0091] In some examples, the system supports multiple BWPs, where the LP-WUS configuration is part of the BWP configuration. Switching between BWPs allows the system to change the configuration of the LP-WUS. For example, BWP1 contains a first configuration and BWP2 contains a second configuration. If the UE is switched between BWP1 and BWP2, the LP- WUS is switched between the first configuration and the second configuration.

[0092] In some examples, the WUS may include multiple parts. The first part of the WUS may indicate the configuration information for the second part of the WUS. For example, the first part of the WUS may consist of synchronisation sequences, allowing for a correlation detector at the UE to detect the sequence and allowing coarse time and frequency synchronisation to be achieved by the UE. The second part of the WUS may contain signalling information for the UE. For example, the second part of the WUS may contain information on the cell ID that the WUS is transmitted from, and / or the UE-ID (or group ID) of the UE being woken up. This second part of the WUS may use a different waveform to the first part of the WUS (for example, the first part of the WUS could consist of a correlation sequence and the second part of the WUS could carry data encoded using OOK, FSK or OFDM).

[0093] In some cases, a particular characteristic of the first part of the WUS may also identify a characteristic of the second part of the WUS. For example: • A preamble sequence (used by the UE to obtain time and frequency synchronisation with the network) in the first part of the WUS may indicate the configuration of the second part of the WUS. For example, if preamble sequence 1 is used, this may indicate that the second part of the WUS uses an OOK-based waveform, and if preamble sequence 2 is used, this may indicate that it uses an FSK-based waveform; However, if, for example, preamble sequence 3 is used, this may indicate that only a preamble is sent in this LP-WUS instance and no second part is transmitted. This may be useful if no LP-WUS has been sent to a group of UEs for some time and only a preamble is sent to enable the LP-WUR of the UEs to resynchronise.

[0094] • The number of preamble sequences in the first part of the WUS may indicate the configuration of the second part of the WUS. For example, if there is a single preamble sequence, this may indicate that the second part of the WUS uses an OOK-based waveform and if there is more than one preamble sequence, the second part of the WUS uses an OFDM-based waveform. This example is based on the observation that preamble repetition could be used when coverage conditions are worse and in these conditions, a more robust WUS would be required (which could be achieved using the OFDM waveform).

[0095] • A preamble sequence of the first part of the WUS may indicate how many bits are carried by the second part of the WUS. This allows the system to adapt to coverage conditions (where it is desirable to transmit fewer bits and hence lower the code rate). Alternatively, the amount of resources used by the second part of the WUS may be adapted based on the preamble sequence used in the first part of the WUS. For example, if few UEs are to be woken up, the second part may transmit fewer bits, or if there is congestion in the system, the amount of data carried by the second part of the WUS can be minimised.

[0096] Figure 10 illustrates a flowchart for an example method of operating a communications device (e.g. UE) according to the present disclosure. In step 1010, the communications device identifies configuration information for a LP-WUS. One or more parameters (e.g. the frequency range, time window and / or waveform structure) of the configuration information may, for example, be received from an infrastructure equipment (e.g. via SIB, RRC or MAC CE signalling), or be defined in the specifications. In step 1020, the communications device monitors for the LP-WUS based on the identified configuration information. That is, the communications device utilises its low-power receiver, while the main receiver is in an off state, to monitor for the LP-WUS according to the configuration parameters. For example, the communications device may monitor for the LP-WUS in a frequency range and / or time window defined in the configuration information. The communications device may also monitor for the LP-WUS according to a number of additional or alternative parameters of the configuration information, as discussed above.

[0097] Figure 11 illustrates a flowchart for an example method of operating an infrastructure equipment (e.g. gNB) according to the present disclosure. In step 1110, the infrastructure equipment transmits, to a communications device, a LP-WUS in accordance with configuration information defined for the LP-WUS. For example, the configuration information for the LP- WUS may define a particular time window and / or frequency range in which the LP-WUS is to be transmitted, and as such the infrastructure equipment transmits the LP-WUS according to this time window and / or frequency range. An indication of one or more parameters of the configuration information (e.g. the frequency range, time window and / or waveform structure) may be transmitted to the communications device by the infrastructure equipment, or by a different infrastructure equipment of the network. Alternatively, one or more parameters of the configuration information may be defined in the specifications.

[0098] As such, from one perspective, there has been described Methods, communications devices and infrastructure equipment for allowing a communications device to identify configuration information for a low-power wake up signal to be monitored for by a low-power receiver of the communications device. The configuration information is available to the UE during RRC idle mode, and based on the configuration information, the low-power receiver monitors for the low-power wake up signal.

[0099] Further examples of feature combinations taught by the present disclosure are set out in the following numbered clauses:

[0100] 1. A method of operating a communications device comprising a low-power receiver and a main receiver, wherein the communications device is configured to transmit signals to and / or to receive signals from an infrastructure equipment of a wireless communications network via a wireless radio interface provided by the wireless communications network, the method comprising: identifying configuration information for a low-power wake-up signal, LP-WLIS; and based on the identified configuration information, monitoring for the LP-WLIS using the low-power receiver while the low-power receiver is in an on state and the main receiver is in an off state.

[0101] 2. The method according to clause 1 , wherein the configuration information indicates a frequency range in which the LP-WLIS is located.

[0102] 3. The method according to clause 2, wherein the frequency range is indicated by an absolute radio frequency (ARF) and a bandwidth.

[0103] 4. The method according to clause 3, wherein the ARF includes an ARF number (ARFN) and an offset relative to the ARFN.

[0104] 5. The method according to clause 2, wherein the frequency range is indicated by a resource element (RE) index and a number of occupied REs.

[0105] 6. The method according to clause 2 or 5, wherein the frequency range is indicated by a resource block (RB) index and a number of occupied RBs.

[0106] 7. The method according to any of clauses 2, 5, or 6, wherein a start or middle of the frequency range is indicated by a resource block (RB) index and an offset of a number of resource elements (REs), and wherein a width of the frequency range is indicated by an integer number of RBs and a number of REs.

[0107] 8. The method according to any of clauses 2-7, wherein the frequency range is indicated relative to a configured bandwidth part (BWP).

[0108] 9. The method according to any of clauses 2-8, wherein the frequency range falls in an initial BWP or a default BWP for the UE.

[0109] 10. The method according to any of clauses 2-9, wherein the frequency range is in a current active BWP. 11 . The method according to any of clauses 2-9, wherein the frequency range is outside a bandwidth of a component carrier used for downlink communications to the communications device.

[0110] 12. The method according to any preceding clause, wherein the configuration information indicates a start time of the LP-WLIS.

[0111] 13. The method according to clause 12, wherein the start time is indicated by an offset relative to a configured discontinuous reception (DRX) ON time.

[0112] 14. The method according to clause 12, wherein the start time is indicated by a subframe index, and an offset from the subframe index.

[0113] 15. The method according to clause 13 or clause 14, wherein the offset is indicated by a number of slots, orthogonal frequency-division multiplexing (OFDM) symbols, or clock cycles.

[0114] 16. The method according to any preceding clause, wherein the configuration information indicates a duration of the LP-WLIS.

[0115] 17. The method according to clause 16, wherein the duration is indicated as a number of OFDM symbols or subframes.

[0116] 18. The method according to any preceding clause, wherein the configuration information indicates a waveform structure of the LP-WLIS.

[0117] 19. The method according to clause 18, wherein the waveform structure includes a subcarrier spacing, modulation, coding rate, amount of data carried, and / or number of repetitions of the LP-WLIS.

[0118] 20. The method according to any preceding clause, wherein the configuration information indicates a cell ID of a cell on which the LP-WLIS is to be transmitted.

[0119] 21 . The method according to any preceding clause, wherein the configuration information indicates a periodicity of occurrence of the LP-WLIS.

[0120] 22. The method according to any preceding clause, wherein identifying the configuration information includes receiving the configuration information in a system information broadcast from the infrastructure equipment.

[0121] 23. The method according to clause 22, further comprising: receiving the system information broadcast comprising the configuration information; and based on receiving the configuration information in the system information broadcast, transitioning to an idle mode in which the low-power receiver is in the on state and the main receiver is in the off state.

[0122] 24. The method according to clause 23, further comprising: activating the main receiver from the off state to the on state to attempt to receive the system information broadcast comprising the configuration information.

[0123] 25. The method according to any preceding clause, wherein identifying the configuration information includes receiving the configuration information in radio resource control (RRC) or medium access control (MAC) control element (CE) signalling from the infrastructure equipment. 26. The method according to any preceding clause, wherein the identifying the configuration information includes receiving the configuration information as part of a BWP configuration.

[0124] 27. The method according to any preceding clause, further comprising transmitting, to the infrastructure equipment, a request for the configuration information.

[0125] 28. The method according to any preceding clause, wherein the LP-WLIS includes two portions, wherein a first portion of the LP-WLIS indicates control information for a second portion of the LP-WLIS.

[0126] 29. The method according to clause 28, wherein the configuration information for the second portion of the LP-WLIS is indicated by one or more characteristics of the first portion of the LP-WUS.

[0127] 30. The method according to clause 29, wherein the one or more characteristics of the first portion of the LP-WUS include a preamble sequence, and / or a number of preamble sequences.

[0128] 31 . The method according to clause 30, wherein a preamble sequence of the first portion of the LP-WUS indicates a waveform structure of the second portion of the LP-WUS and / or a presence of the second portion of the LP-WUS.

[0129] 32. The method according to any preceding clause, wherein one or more parameters of the control information are predefined in specifications.

[0130] 33. The method according to any preceding clause, comprising: identifying configuration information for a LP-WUS for each of a plurality of cells; monitoring, using the low-power receiver while the low-power receiver is in an on state and the main receiver is in an off state, each of the plurality of cells for a respective LP-WUS.

[0131] 34. The method according to clause 33, further comprising: determining a received power of the respective LP-WUS for each of the plurality of cells; and based on the received power of the respective LP-WUS for each of the plurality of cells, determine a cell to monitor for paging.

[0132] 35. A communications device comprising: a low-power receiver; a main receiver; and at least one controller configured to control the communications device to: identify configuration information for a low-power wake-up signal, LP-WUS; and based on the identified configuration information, monitor for the LP-WUS using the low-power receiver while the low- power receiver is in an on state and the main receiver is in an off state.

[0133] 36. Circuitry for a communications device comprising: low-power receiver circuitry, main receiver circuitry, and at least one controller circuitry configured to control the communications device to: identify configuration information for a low-power wake-up signal, LP-WUS; and based on the identified configuration information, monitor for the LP-WUS using the low-power receiver while the low-power receiver is in an on state and the main receiver is in an off state.

[0134] 37. A method of operating an infrastructure equipment of a wireless communications network, wherein the infrastructure equipment is configured to transmit signals to and / or to receive signals from a communications device via a wireless radio interface provided by the wireless communications network, the method comprising: transmitting, to the communications device, a low-power wake-up signal, LP-WLIS, in accordance with configuration information defined for the LP-WLIS.

[0135] 38. The method according to clause 37, further comprising: transmitting, to the communications device, an indication of the configuration information.

[0136] 39. The method according to clause 38, wherein the infrastructure equipment transmits the configuration information in a system information broadcast.

[0137] 40. The method according to clause 38, wherein the infrastructure equipment transmits the configuration information in radio resource control (RRC) or medium access control (MAC) control element (CE) signalling to the communications device.

[0138] 41. The method according to any of clauses 38-40, wherein the infrastructure equipment transmits the configuration information as part of a configuration of a bandwidth part (BWP) for the communications device.

[0139] 42. The method according to any of clauses 38-41 , further comprising: receiving, from the communications device, a request for the configuration information.

[0140] 43. The method according to any of clauses 37-42, wherein one or more parameters of the control information are predefined in specifications.

[0141] 44. The method according to any of clauses 37-43, wherein the LP-WLIS includes two portions, wherein a first portion of the LP-WLIS indicates control information for a second portion of the LP-WLIS.

[0142] 45. The method according to clause 44, wherein the control information for the second portion of the LP-WLIS is indicated by one or more characteristics of the first portion of the LP- WUS.

[0143] 46. The method according to clause 45, wherein the one or more characteristics of the first portion of the LP-WLIS include a preamble sequence, and / or a number of preamble sequences.

[0144] 47. The method according to clause 46, wherein a preamble sequence of the first portion of the LP-WLIS indicates a waveform structure of the second portion of the LP-WLIS and / or a presence of the second portion of the LP-WLIS.

[0145] 48. The method according to any of clauses 37-47, wherein the configuration information defines a frequency range in which the LP-WLIS is located.

[0146] 49. The method according to clause 48, wherein the frequency range is defined by an absolute radio frequency (ARF) and a bandwidth.

[0147] 50. The method according to clause 49, wherein the ARF is defined by an ARF number (ARFN) and an offset relative to the ARFN.

[0148] 51. The method according to clause 48, wherein the frequency range is defined by a resource element (RE) index and a number of occupied REs.

[0149] 52. The method according to clause 48 or 51 , wherein the frequency range is defined by a resource block (RB) index and a number of occupied RBs. 53. The method according to any of clauses 48, 51 , or 52, wherein a start or middle of the frequency range is defined by a resource block (RB) index and an offset of a number of resource elements (REs), and wherein a width of the frequency range is defined by an integer number of RBs and a number of REs.

[0150] 54. The method according to any of clauses 48-53, wherein the frequency range is defined relative to a configured bandwidth part (BWP).

[0151] 55. The method according to any of clauses 48-54, wherein the frequency range falls in an initial BWP or a default BWP for the UE.

[0152] 56. The method according to any of clauses 48-55, wherein the frequency range is in a current active BWP.

[0153] 57. The method according to any of clauses 48-55, wherein the frequency range is outside a bandwidth of a component carrier used for downlink communications to the communications device.

[0154] 58. The method according to any of clauses 37-57, wherein the configuration information defines a start time of the LP-WLIS.

[0155] 59. The method according to clause 58, wherein the start time is defined by an offset relative to a configured discontinuous reception (DRX) ON time.

[0156] 60. The method according to clause 59, wherein the start time is defined by a subframe index, and an offset from the subframe index.

[0157] 61. The method according to clause 59 or clause 60, wherein the offset is defined by a number of slots, orthogonal frequency-division multiplexing (OFDM) symbols, or clock cycles.

[0158] 62. The method according to any of clauses 37-61 , wherein the configuration information defines a duration of the LP-WLIS.

[0159] 63. The method according to clause 62, wherein the duration is defined by a number of OFDM symbols or subframes.

[0160] 64. The method according to any of clauses 37-63, wherein the configuration information defines a waveform structure of the LP-WLIS.

[0161] 65. The method according to clause 64, wherein the waveform structure defines a subcarrier spacing, modulation, coding rate, amount of data carried, and / or number of repetitions of the LP-WLIS.

[0162] 66. The method according to any of clauses 37-65, wherein the configuration information defines a cell ID of a cell provided by the infrastructure equipment.

[0163] 67. The method according to any of clauses 37-66, wherein the configuration information defines a periodicity of occurrence of the LP-WLIS.

[0164] 68. An infrastructure equipment forming part of a wireless communications network, the infrastructure equipment comprising: a transceiver, and a controller configured in combination with the transceiver to: transmit, to the communications device, a low-power wake-up signal, LP-WLIS, in accordance with configuration information defined for the LP-WLIS. 69. Circuitry for infrastructure equipment forming part of a wireless communications network, the circuitry comprising: transceiver circuitry, and controller circuitry configured in combination with the transceiver circuitry to: transmit, to the communications device, a low- power wake-up signal, LP-WLIS, in accordance with configuration information defined for the LP-WUS.

[0165] REFERENCES

[0166] [1] Holma H. and Toskala A, “LTE for UMTS OFDMA and SC-FDMA based radio access”, John Wiley and Sons, 2009.

[0167] [2] TR 38.913, “3rdGeneration Partnership Project; Technical Specification Group Radio Access Network; Study on Scenarios and Requirements for Next Generation Access

[0168] Technologies (Release 14)”, 3GPP, v14.3.0, August 2017.

[0169] [3] R1-1708311 , “Idle Mode Power Efficiency Reduction,” Sierra Wireless, RAN1#89.

[0170] [4] TR 38.840, “NR: Study on UE Power Saving (Release 16, vO.1.0)”, 3GPP, November 2018. [5] RP-222644, “Revised SID: Study on low-power Wake-up Signal and Receiver for NR”,

[0171] RANP#97e, September 2022.

[0172] [6] 3GPP TS 38.101 ; NR; User Equipment (UE) radio transmission and reception; Part 1: Range 1 Standalone.

Claims

CLAIMS1. A method of operating a communications device comprising a low-power receiver and a main receiver, wherein the communications device is configured to transmit signals to and / or to receive signals from an infrastructure equipment of a wireless communications network via a wireless radio interface provided by the wireless communications network, the method comprising: identifying configuration information for a low-power wake-up signal, LP-WUS; and based on the identified configuration information, monitoring for the LP-WUS using the low-power receiver while the low-power receiver is in an on state and the main receiver is in an off state.

2. The method according to claim 1 , wherein the configuration information indicates a frequency range in which the LP-WUS is located.

3. The method according to claim 2, wherein the frequency range is indicated by an absolute radio frequency (ARF) and a bandwidth.

4. The method according to claim 3, wherein the ARF includes an ARF number (ARFN) and an offset relative to the ARFN.

5. The method according to claim 2, wherein the frequency range is indicated by a resource element (RE) index and a number of occupied REs.

6. The method according to claim 2, wherein the frequency range is indicated by a resource block (RB) index and a number of occupied RBs.

7. The method according to claim 2, wherein a start or middle of the frequency range is indicated by a resource block (RB) index and an offset of a number of resource elements (REs), and wherein a width of the frequency range is indicated by an integer number of RBs and a number of REs.

8. The method according to claim 2, wherein the frequency range is indicated relative to a configured bandwidth part (BWP).

9. The method according to claim 2, wherein the frequency range falls in an initial BWP or a default BWP for the UE.

10. The method according to claim 2, wherein the frequency range is in a current active BWP.

11. The method according to claim 2, wherein the frequency range is outside a bandwidth of a component carrier used for downlink communications to the communications device.

12. The method according to claim 1 , wherein the configuration information indicates a start time of the LP-WLIS.

13. The method according to claim 12, wherein the start time is indicated by an offset relative to a configured discontinuous reception (DRX) ON time.

14. The method according to claim 12, wherein the start time is indicated by a subframe index, and an offset from the subframe index.

15. The method according to claim 13, wherein the offset is indicated by a number of slots, orthogonal frequency-division multiplexing (OFDM) symbols, or clock cycles.

16. The method according to claim 1 , wherein the configuration information indicates a duration of the LP-WLIS.

17. The method according to claim 16, wherein the duration is indicated as a number of OFDM symbols or subframes.

18. The method according to claim 1 , wherein the configuration information indicates a waveform structure of the LP-WLIS.

19. The method according to claim 18, wherein the waveform structure includes a subcarrier spacing, modulation, coding rate, amount of data carried, and / or number of repetitions of the LP-WLIS.

20. The method according to claim 1 , wherein the configuration information indicates a cell ID of a cell on which the LP-WLIS is to be transmitted.

21. The method according to claim 1 , wherein the configuration information indicates a periodicity of occurrence of the LP-WLIS.

22. The method according to claim 1, wherein identifying the configuration information includes receiving the configuration information in a system information broadcast from the infrastructure equipment.

23. The method according to claim 22, further comprising: receiving the system information broadcast comprising the configuration information; and based on receiving the configuration information in the system information broadcast, transitioning to an idle mode in which the low-power receiver is in the on state and the main receiver is in the off state.

24. The method according to claim 23, further comprising: activating the main receiver from the off state to the on state to attempt to receive the system information broadcast comprising the configuration information.

25. The method according to claim 1, wherein identifying the configuration information includes receiving the configuration information in radio resource control (RRC) or medium access control (MAC) control element (CE) signalling from the infrastructure equipment.

26. The method according to claim 1 , wherein the identifying the configuration information includes receiving the configuration information as part of a BWP configuration.

27. The method according to claim 1 , further comprising transmitting, to the infrastructure equipment, a request for the configuration information.

28. The method according to any preceding claim, wherein the LP-WLIS includes two portions, wherein a first portion of the LP-WLIS indicates control information for a second portion of the LP-WLIS.

29. The method according to claim 28, wherein the configuration information for the second portion of the LP-WLIS is indicated by one or more characteristics of the first portion of the LP-WUS.

30. The method according to claim 29, wherein the one or more characteristics of the first portion of the LP-WUS include a preamble sequence, and / or a number of preamble sequences.31 . The method according to claim 30, wherein a preamble sequence of the first portion of the LP-WLIS indicates a waveform structure of the second portion of the LP-WLIS and / or a presence of the second portion of the LP-WLIS.

32. The method according to claim 1 , wherein one or more parameters of the control information are predefined in specifications.

33. The method according to claim 1 , comprising: identifying configuration information for a LP-WLIS for each of a plurality of cells; monitoring, using the low-power receiver while the low-power receiver is in an on state and the main receiver is in an off state, each of the plurality of cells for a respective LP-WLIS.

34. The method according to claim 33, further comprising: determining a received power of the respective LP-WLIS for each of the plurality of cells; and based on the received power of the respective LP-WLIS for each of the plurality of cells, determine a cell to monitor for paging.

35. A communications device comprising: a low-power receiver; a main receiver; and at least one controller configured to control the communications device to: identify configuration information for a low-power wake-up signal, LP-WLIS; and based on the identified configuration information, monitor for the LP-WLIS using the low-power receiver while the low-power receiver is in an on state and the main receiver is in an off state.

36. Circuitry for a communications device comprising low-power receiver circuitry, main receiver circuitry, and at least one controller circuitry configured to control the communications device to: identify configuration information for a low-power wake-up signal, LP-WLIS; and based on the identified configuration information, monitor for the LP-WLIS using the low-power receiver while the low-power receiver is in an on state and the main receiver is in an off state.

37. A method of operating an infrastructure equipment of a wireless communications network, wherein the infrastructure equipment is configured to transmit signals to and / or to receive signals from a communications device via a wireless radio interface provided by the wireless communications network, the method comprising: transmitting, to the communications device, a low-power wake-up signal, LP-WLIS, in accordance with configuration information defined for the LP-WLIS.

38. The method according to claim 37, further comprising: transmitting, to the communications device, an indication of the configuration information.

39. The method according to claim 38, wherein the infrastructure equipment transmits the configuration information in a system information broadcast.

40. The method according to claim 38, wherein the infrastructure equipment transmits the configuration information in radio resource control (RRC) or medium access control (MAC) control element (CE) signalling to the communications device.41 . The method according to claim 38, wherein the infrastructure equipment transmits the configuration information as part of a configuration of a bandwidth part (BWP) for the communications device.

42. The method according to claim 38, further comprising: receiving, from the communications device, a request for the configuration information.

43. The method according to claim 37, wherein one or more parameters of the control information are predefined in specifications.

44. The method according to claim 37, wherein the LP-WLIS includes two portions, wherein a first portion of the LP-WLIS indicates control information for a second portion of the LP-WUS.

45. The method according to claim 44, wherein the control information for the second portion of the LP-WUS is indicated by one or more characteristics of the first portion of the LP- WUS.

46. The method according to claim 45, wherein the one or more characteristics of the first portion of the LP-WLIS include a preamble sequence, and / or a number of preamble sequences.

47. The method according to claim 46, wherein a preamble sequence of the first portion of the LP-WLIS indicates a waveform structure of the second portion of the LP-WLIS and / or a presence of the second portion of the LP-WLIS.

48. The method according to claim 37, wherein the configuration information defines a frequency range in which the LP-WLIS is located.

49. The method according to claim 48, wherein the frequency range is defined by an absolute radio frequency (ARF) and a bandwidth.

50. The method according to claim 49, wherein the ARF is defined by an ARF number (ARFN) and an offset relative to the ARFN.

51. The method according to claim 48, wherein the frequency range is defined by a resource element (RE) index and a number of occupied REs.

52. The method according to claim 48, wherein the frequency range is defined by a resource block (RB) index and a number of occupied RBs.

53. The method according to claim 48, wherein a start or middle of the frequency range is defined by a resource block (RB) index and an offset of a number of resource elements (REs), and wherein a width of the frequency range is defined by an integer number of RBs and a number of REs.

54. The method according to claim 48, wherein the frequency range is defined relative to a configured bandwidth part (BWP).

55. The method according to claim 48, wherein the frequency range falls in an initial BWP or a default BWP for the UE.

56. The method according to claim 48, wherein the frequency range is in a current active BWP.

57. The method according to claim 48, wherein the frequency range is outside a bandwidth of a component carrier used for downlink communications to the communications device.

58. The method according to claim 37, wherein the configuration information defines a start time of the LP-WLIS.

59. The method according to claim 58, wherein the start time is defined by an offset relative to a configured discontinuous reception (DRX) ON time.

60. The method according to claim 59, wherein the start time is defined by a subframe index, and an offset from the subframe index.

61. The method according to claim 59, wherein the offset is defined by a number of slots, orthogonal frequency-division multiplexing (OFDM) symbols, or clock cycles.

62. The method according to claim 37, wherein the configuration information defines a duration of the LP-WLIS.

63. The method according to claim 62, wherein the duration is defined by a number of OFDM symbols or subframes.

64. The method according to claim 37, wherein the configuration information defines a waveform structure of the LP-WLIS.

65. The method according to claim 64, wherein the waveform structure defines a subcarrier spacing, modulation, coding rate, amount of data carried, and / or number of repetitions of the LP-WLIS.

66. The method according to claim 37, wherein the configuration information defines a cell ID of a cell provided by the infrastructure equipment.

67. The method according to claim 37, wherein the configuration information defines a periodicity of occurrence of the LP-WLIS.

68. An infrastructure equipment forming part of a wireless communications network, the infrastructure equipment comprising: a transceiver, anda controller configured in combination with the transceiver to: transmit, to the communications device, a low-power wake-up signal, LP-WLIS, in accordance with configuration information defined for the LP-WLIS.

69. Circuitry for infrastructure equipment forming part of a wireless communications network, the circuitry comprising: transceiver circuitry, and controller circuitry configured in combination with the transceiver circuitry to: transmit, to the communications device, a low-power wake-up signal, LP-WLIS, in accordance with configuration information defined for the LP-WLIS.

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