Side link positioning

Abstract

Examples of the present disclosure relate to sidelink positioning. In an example of the present disclosure, a terminal device may be configured to detect a wake-up signal while in a discontinuous reception (DRX) off mode. A wake-up signal is transmitted from the other terminal device, and the wake-up signal includes an indication of a DRX level of the other terminal device. The terminal device may be configured to support positioning of another terminal device based on the DRX level indicated in the wake-up signal.

Description

Technical Field

[0001] Examples of the present disclosure relate to sidelink positioning. Some examples relate to sidelink positioning using discontinuous reception (DRX). Background Art

[0002] Sidelink positioning enables a terminal device to perform a positioning process with other terminal devices without the participation of a base station in the messages. In such a process, some terminal devices will act as anchor devices and some terminal devices will act as target devices. Summary of the Invention

[0003] According to various but not necessarily all examples of the present disclosure, a terminal device may be provided that includes components for:

[0004] detecting a wake-up signal when in discontinuous reception (DRX) off mode, where the wake-up signal is sent from another terminal device and includes an indication of the DRX level of the other terminal device; and

[0005] supporting the positioning of the other terminal device based on the DRX level indicated in the wake-up signal.

[0006] The wake-up signal may include an indication of a sidelink positioning request.

[0007] Supporting the positioning of the other terminal device may include: determining whether a positioning request from the other terminal device will be served by the terminal device, where the positioning request is associated with sidelink signaling between the terminal device and the other terminal device.

[0008] The component may be used to determine how a sidelink positioning request can be served.

[0009] The component may be used to control whether the DRX mode of the terminal device is on or off based on determining whether the sidelink positioning request can be served by the terminal device.

[0010] The component may be used to switch the terminal device to DRX on mode if it is determined that the sidelink positioning request can be served by the terminal device.

[0011] The component may be used to cause the transmission of a message indicating that the sidelink positioning request can be accepted, where the message includes an indication of the DRX level of the terminal device.

[0012] The component may be used to maintain the terminal device in DRX off mode if it is determined that the sidelink positioning request cannot be served by the terminal device.

[0013] Supporting positioning may be based on a DRX level hierarchy.

[0014] The hierarchical structure of DRX levels can be configured such that a terminal device can act as an anchor for another terminal device of a higher or equal level.

[0015] The hierarchical structure of DRX levels can be configured such that higher DRX levels have longer sleep durations than lower DRX levels.

[0016] DRX levels can have predefined sleep cycles.

[0017] DRX levels can be specific to the type of terminal device.

[0018] DRX levels can have at least one of the following: a specific timing of a wake-up signal, a specific signature of a wake-up signal.

[0019] This component can be used to provide anchoring capabilities.

[0020] According to various but not necessarily all examples of the present disclosure, a method can be provided that includes:

[0021] Detecting a wake-up signal when in discontinuous reception (DRX) off mode, where the wake-up signal is sent from another terminal device and includes an indication of the DRX level of the other terminal device; and

[0022] Supporting the positioning of another terminal device based on the DRX level indicated in the wake-up signal.

[0023] According to various but not necessarily all examples of the present disclosure, a computer program can be provided that includes instructions that, when executed by a processor, cause a terminal device to perform at least:

[0024] Detecting a wake-up signal when in discontinuous reception (DRX) off mode, where the wake-up signal is sent from another terminal device and includes an indication of the DRX level of the other terminal device; and

[0025] Supporting the positioning of another terminal device based on the DRX level indicated in the wake-up signal.

[0026] According to various but not necessarily all examples of the present disclosure, a terminal device can be provided that includes components for:

[0027] Causing a wake-up signal to be transmitted to one or more candidate terminal devices, the wake-up signal including an indication of the discontinuous reception (DRX) level of the terminal device; and

[0028] Collecting responses from candidate terminal devices having a suitable DRX level, where the suitability of the DRX level is determined based on the DRX level hierarchical structure.

[0029] The wake-up signal may include an indication of a sidelink positioning request.

[0030] Suitable DRX levels may include matching DRX levels.

[0031] The wake-up signal may be sent after a sidelink positioning request from an application.

[0032] The component may be used to select one or more candidate terminal devices from candidate terminal devices based at least in part on the DRX level.

[0033] The wake-up signal may include a point-to-multipoint signal.

[0034] According to various but not necessarily all examples of the present disclosure, a method may be provided that includes:

[0035] Causing a wake-up signal to be transmitted to one or more candidate terminal devices, the wake-up signal including an indication of a discontinuous reception (DRX) level of the terminal device; and

[0036] Collecting responses from candidate terminal devices having a suitable DRX level, wherein the suitability of the DRX level is determined based on a DRX level hierarchy.

[0037] According to various but not necessarily all examples of the present disclosure, a computer program may be provided that includes instructions that, when executed by a processor, cause a terminal device to at least perform:

[0038] Causing a wake-up signal to be transmitted to one or more candidate terminal devices, the wake-up signal including an indication of a discontinuous reception (DRX) level of the terminal device; and

[0039] Collecting responses from candidate terminal devices having a suitable DRX level, wherein the suitability of the DRX level is determined based on a DRX level hierarchy.

[0040] Although the above examples and optional features of the present disclosure are described separately, it should be understood that their provision in all possible combinations and permutations is included within the present disclosure. It should be understood that various examples of the present disclosure may include any or all of the features described in other examples of the present disclosure, and vice versa. Moreover, it should be understood that any one or more or all of the features may be implemented / included / executed in any combination as needed and appropriately by a device, method, and / or computer program instructions. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Some examples will now be described with reference to the drawings, in which:

[0042] Figure 1 An example network is shown;

[0043] Figure 2 Side link positioning is shown;

[0044] Figure 3 Side link positioning is shown;

[0045] Figure 4 An example method is shown;

[0046] Figure 5 Another example method is shown;

[0047] Figure 6 An example signal diagram is shown;

[0048] Figure 7 An example method is shown;

[0049] Figure 8 Another example method is shown; and

[0050] Figure 9 An example controller is shown.

[0051] These figures are not necessarily drawn to scale. For clarity and conciseness, certain features and views of the figures may be shown schematically or enlarged in scale. For example, the dimensions of some elements in the figures may be enlarged relative to other elements to assist in the explanation. Corresponding reference numerals are used in the figures to designate corresponding features. For clarity, not all reference numerals may be shown in all figures.

[0052] Definition

[0053] AMF Access and Mobility Function

[0054] AoD Angle of Departure

[0055] AS Access Stratum

[0056] DL Downlink

[0057] DRX Discontinuous Reception

[0058] gNB NR Base Station

[0059] HARQ Hybrid Automatic Repeat reQuest

[0060] ID Identification

[0061] IIOT Industrial Internet of Things

[0062] L2 Layer 2

[0063] LDPC Low Density Parity Check

[0064] LPHAP Low Power High Accuracy Positioning

[0065] NR New Radio

[0066] OFDM Orthogonal Frequency Division Multiplexing

[0067] O-RAN Open Radio Access Network

[0068] PSSCH Physical SideLink Control Channel

[0069] QAM Quadrature Amplitude Modulation

[0070] QoS Quality of Service

[0071] RAN Radio Access Network

[0072] RedCap Reduced Capability

[0073] RRC Radio Resource Control

[0074] RTT Round-Trip Time

[0075] SCI SideLink Control Information

[0076] SL SideLink

[0077] SL PRS SideLink Positioning Reference Signal

[0078] UE User Equipment

[0079] UL Uplink

[0080] WUSP Wake-Up Signal for SL Positioning Detailed implementation manners

[0081] Figure 1 An example of network 100 including multiple network entities is illustrated. The multiple network entities include terminal device 110, node 120, and one or more network devices 130. Terminal device 110 and node 120 communicate with each other. One or more network devices 130 communicate with access node 120. In some examples, one or more network devices 130 communicate with terminal device 110.

[0082] In some examples, one or more network devices 130 may communicate with each other. In some examples, one or more nodes 120 may communicate with each other. In some examples, one or more terminal devices 110 may communicate with each other.

[0083] Network 100 may be a cellular network including multiple cells 122, and each cell 122 is served by node 120 or multiple nodes. In this example, the interface between terminal device 110 and the node 120 defining cell 122 is wireless interface 124.

[0084] The node 120 includes one or more cellular radio transceivers. The terminal device 110 includes one or more cellular radio transceivers.

[0085] In the example shown, the cellular network 100 is a 3rd Generation Partnership Project (3GPP) network, where the terminal device 110 is a user equipment (UE), and the node 120 can be an access node such as a base station.

[0086] The term "user equipment" is used to specify a mobile device that includes a smart card for authentication / encryption etc., such as a subscriber identity module (SIM). In some examples, the term "user equipment" is used to specify a mobile device that includes circuitry embedded as part of the user equipment for authentication / encryption, such as a software SIM. Some examples of user equipment include a mobile station (mobile phone), smartphone, personal digital assistant (PDA), handset, device using a wireless modem (alarm or measurement device etc.), laptop and / or touchscreen computer, tablet, game console, notebook, smart glasses, and multimedia device.

[0087] The node 120 can be any suitable base station. A base station is an access node. It can be a network element responsible for radio transmission and reception to or from the terminal device 110 in one or more cells. The node 120 can be a network element in a radio access network (RAN), an open radio access network (O-RAN), or any other suitable type of network.

[0088] The network device 130 can be part of the core network. The network device 130 can be configured to manage functions related to the connectivity of the terminal device 110. For example, the network device 130 can be configured to manage functions such as connectivity, mobility, authentication, authorization, and / or other suitable functions. In some examples, the network device 130 can include an access and mobility management function (AMF) and / or a user plane function (UPF) or any other suitable entity.

[0089] In Figure 1 the example, the network device 130 is shown as a single entity. In some examples, the network device 130 can be distributed across multiple entities. For example, the network device 130 can be distributed based on the cloud or in any other suitable manner.

[0090] Network 100 can be, for example, a 4G or 5G network. It can be, for example, a New Radio (NR) network that uses a gNB or eNB as access node 120. New Radio is the 3GPP name for 5G technology. In this case, node 120 can include gNodeB (gNB) 120, which is configured to provide user plane and control plane protocol termination to UE 110, and / or perform any other suitable functions. gNBs 120 are interconnected with each other via the X2 / Xn interface 126. The gNB is also connected to network device 130 via the N2 interface 128. The gNB can be connected to an AMF or any other suitable network device 130. Other types of networks and interfaces can be used in other examples. Other types of networks can include next-generation mobile and communication networks, such as, for example, a 6G network.

[0091] Network 100 can also support sidelink (SL) communication. SL communication can include direct communication between two UEs 110 with or without the participation of gNB 120 in the transmission and reception of signals. SL can be used for sidelink positioning.

[0092] Figure 2 An example of an SL positioning scenario is shown. Figure 2 The target UE 110-T, the first anchor UE 110-A, and the second anchor UE 110-A are shown.

[0093] In this example, UE 110 includes a vehicle or a device connected to a vehicle. Other types of UEs 110 can be used in other examples.

[0094] In the SL positioning scenario, the target UE 110-T is the UE 110 to be positioned, and the anchor UE 110-A is the UE 110 that can support the positioning of the target UE 110-T. The anchor UE 110-A can support the positioning of the target UE 110-T by sending and / or receiving reference signals on the SL interface. In Figure 2 the example, one target UE 110-T and two anchor UEs 110-A are shown. Other numbers of corresponding UEs 110 can be used in other scenarios. SL positioning is similar to uplink / downlink (UL / DL) positioning, where the gNB 120 acting as an anchor sends / receives reference signals to / from the target UE 110 for positioning.

[0095] Any suitable process can be used to enable SL positioning. In some examples, a sidelink positioning reference signal (SL PRS) can be sent from a corresponding anchor UE 110-A and received by a target UE 110-T, or there can be an SL PRS exchange between the anchor UE 110-A and the target UE 110-T during an SL session. Leveraging the exact latency and accuracy requirements of the corresponding SL session can enable SL positioning.

[0096] In Figure 2 the SL positioning scenario shown, the target UE 110-T is performing an SL positioning session. In the SL positioning session, the target UE 110-T exchanges SL-PRS with two anchor UEs 110-A to determine the location of the target UE 110-T. In this scenario, the anchor UE 110-A is said to provide SL-PRS assistance to the target UE 110-T.

[0097] To reduce power consumption, discontinuous reception (DRX) can be used for SL communication sessions. A DRX cycle with DRX-on and DRX-off configurations can be defined for the SL session. The UE 110 can turn off its radio components during the DRX-off duration to save power.

[0098] The SL communication session can support timer-based SL DRX for unicast, multicast, and broadcast signals. Parameters such as on-duration, inactivity timer, retransmission timer, period, and any other suitable parameters can be defined for SL DRX to determine the SL active time for SL DRX.

[0099] During the SL active time for SL DRX, the receiving UE 110 performs monitoring of sidelink control information (SCI) for data reception. For example, the receiving UE 110 monitors the second-stage SCI on the physical sidelink control channel (PSCCH) and PSSCH. During the SL inactive time for SL DRX, the receiving UE 110 does not perform monitoring of SCI for data reception. During the inactive time, the receiving UE 110 can skip monitoring the second-stage SCI on the PSCCH and PSSCH for data reception.

[0100] In this scenario, the SL active time of the receiving UE 110 includes the time when any one of its applicable on-duration timer(s), inactivity timer(s), or retransmission timer(s) (for any one of unicast, multicast, or broadcast) is running.

[0101] In the case of using unicast, the receiving UE 110 is configured to maintain a set of SL DRX timers for multiple pairs of source / destination identifiers (L2IDs) and directions. The receiving UE 110 is configured to start or restart the timer with the value configured for the corresponding pair of source / destination L2ID and direction. The DRX configuration between a pair of source / destination L2 IDs and directions can be negotiated between the sending UE 110 and the receiving UE 110 in the access stratum (AS) layer.

[0102] For the DRX configuration in the corresponding direction, one of the UEs 110 is the sending UE 110 and the other is the receiving UE 110. A sender-centered approach can be supported, whereby:

[0103] · The receiving UE 110 sends auxiliary information to the sending UE using a PC5-Radio Resource Control (RRC) message or any other suitable message.

[0104] · The sending UE 110 uses RRCReconfigurationSidelink to send the SL DRX configuration used by the receiving UE 110 to the receiving UE

[0105] 110.

[0106] When the sending UE 110 is within coverage and in the RRC_CONNECTED mode, the sending UE 110 can report the received auxiliary information to its serving gNB 120 and can obtain the SL DRX configuration to send to the receiving UE 100 in dedicated RRC signaling from the network 100. When the receiving UE 110 is within coverage and in the RRC_CONNECTED mode, the receiving UE 110 can report the received SL DRX configuration to its serving gNB 120.

[0107] The open-duration timer, inactivity timer, hybrid automatic repeat request (HARQ) round-trip time (RTT), and retransmission timer can be supported in the unicast scenario. The SL HARQ RTT timer and SL retransmission timer are maintained at the receiving UE 110 for the corresponding SL HARQ process. The sending UE 110 maintains a timer corresponding to the SL inactivity timer in the receiving UE 110 for the corresponding pair of source / destination L2 IDs and uses this timer as part of the criterion for determining the allowable transmission time to the receiving UE 110.

[0108] For multicast / broadcast, SL DRX can be configured among multiple UEs 110 based on the Quality of Service (QoS) profile and L2 ID. The On Duration timer, Inactivity timer, HARQ RTT, and Retransmission timer are supported for the multicast scenario. The On Duration timer is supported for the broadcast scenario. The SL HARQ RTT timer and SL Retransmission timer are maintained at the receiving UE 110 for the corresponding SL HARQ process. The sending UE 110 maintains a timer corresponding to the SL Inactivity timer in the receiving UE 110 for the corresponding source / destination L2ID pair, and uses this timer as part of the criteria for determining the allowable time to the receiving UE 110.

[0109] The problem with SL DRX definition is that the broadcast SL DRX configuration cannot be dynamically adapted to positioning services. Thus, when applied to SL positioning at the anchoring UE 110, SL DRX cannot ensure a fair balance between power saving and SL positioning update rate for all target UEs 110-T. As described above, SL positioning requirements (such as accuracy, latency, update rate requirements) span a wide range, and the corresponding anchoring UE 110-A may need to support target UEs 110-T with different requirements. In the case where the expected target UE 110-T has strict SL positioning requirements, the anchoring UE 110-A can be configured with a shorter DRX sleep cycle. However, if no such target UE 110-T is nearby, this will result in significant power loss at the anchoring UE 110-A. Conversely, the anchoring UE 110-A can be configured with a longer DRX sleep cycle to save power. However, this may result in the anchoring UE 110-A being unable to support target UEs 110-T with strict SL positioning requirements.

[0110] Figure 3 An example of the problem is shown in. Figure 3 An example side link positioning scenario is shown.

[0111] In this example, the target UE 110-T is to be positioned. Thus, the target UE 110-T must select and activate a set of anchoring UEs 110-A1, 110-A2, 110-A3 with which the target UE 110-T shall exchange SL PRS.

[0112] In Figure 3In the example, there are three candidate anchor UEs 110-A1, 110-A2, and 110-A3 in the area around the target UE 110-T. Different candidate anchor UEs 110-A1, 110-A2, and 110-A3 use different SL DRX configurations. In this case, the first candidate anchor UE 110-A1 uses the first SL DRX configuration, the second candidate anchor UE 110-A2 uses the second SL DRX configuration, and the third candidate anchor UE 110-A3 uses the third SL DRX configuration. Different SL DRX configurations can have different DRX cycle periods, DRX on durations, or any other suitable manner different from others.

[0113] The first problem that may occur in this scenario is that the target UE 110-T may not be able to find sufficient candidate anchor UEs 110-A1, 110-A2, and 110-A3 for the SL positioning session. This problem may occur because the nearby candidate anchor UEs 110-A1, 110-A2, and 110-A3 may have different DRX configurations, causing the SL UE 110 to monitor the SL channel in different time patterns.

[0114] The second problem that occurs is to enable the SL positioning session to be completed within the latency target. This problem may occur even if the target UE 110-T has found sufficient candidate anchor UEs 110-A1, 110-A2, and 110-A3 with the same DRX configuration for the SL positioning session because the DRX cycle may be too long.

[0115] Examples of the present disclosure solve these problems.

[0116] Figure 4 An example method is shown. Figure 4 The method can be implemented by a terminal device, such as the candidate anchor UE 110-A or any other suitable type of device or apparatus.

[0117] At block 400, the method includes detecting a wake-up signal. When the terminal device 110-A is in the DRX off mode, the wake-up signal can be detected by the terminal device 110-A.

[0118] The wake-up signal can be sent from another terminal device 110 1. Another terminal device 110-T can be the target UE 110-T to be located. The wake-up signal can include an indication of the DRX level of another terminal device 110-T. The wake-up signal can include a signature specific to the DRX level of another terminal device 110-T.

[0119] The wake-up signal may include an indication of a sidelink positioning request. The sidelink positioning request may be used to locate another terminal device 110-T that transmits the wake-up signal. The wake-up signal may include a wake-up signal for SL positioning (WUSP) or any other suitable type of signal.

[0120] At block 402, the method includes supporting the positioning of another terminal device 110-T based on the DRX level indicated in the wake-up signal. In some examples, the DRX level may be indicated by the signature of the wake-up signal. The signature may include waveform type, bandwidth, carrier frequency, code, modulation scheme, duration of the signal, or any other suitable characteristics. In some examples, the wake-up signal may include a payload, and the payload may include information indicating the DRX level.

[0121] In some examples, the information associated with the DRX level may be used to support positioning another terminal device 110-T. The information associated with the DRX level may relate to any parameter that defines the DRX level. In some examples, the information associated with the DRX level may include a sleep cycle or any other suitable information.

[0122] Supporting the positioning of another terminal device 110-T may include determining whether a positioning request from another terminal device 110-T will be served by the terminal device 110-A. The positioning request may be associated with sidelink communication between the terminal device 110-A and another terminal device 110-T.

[0123] In some examples, supporting the positioning of another terminal device 110-T may further include determining how the sidelink positioning request can be served. For example, it may include determining whether the positioning request can be delayed or served using specific resources.

[0124] The DRX mode of the terminal device 110-A may be controlled based on determining whether the sidelink positioning request can be served by the terminal device. For example, it may control whether the terminal device 110-A is in the DRX-on mode or the DRX-off mode.

[0125] If it is determined that the sidelink positioning request can be served by the terminal device 110-A, the terminal device 110-A may be switched to the DRX-on mode. After the terminal device 110-A has been switched to the DRX-on mode, a message indicating that the sidelink positioning request can be received may be sent from the terminal device 110-A to another terminal device 110-T. The message may include an indication of the DRX level of the terminal device 110-A.

[0126] If it is determined that the sidelink positioning request cannot be served by the terminal device 110-A, the terminal device 110-A may remain in the DRX-off mode. In this case, the terminal device 110-A does not send a response to the wake-up signal.

[0127] In some examples, the support of the terminal device 110-A for positioning may be based on a DRX level hierarchy. In this case, the hierarchy may be used to compare the DRX level of another terminal device 110-T and the DRX level of the terminal device 110-A. This means that the DRX level of another terminal device 110-T does not need to be the same as the DRX level of the terminal device 110-A, because the DRX level hierarchy can be used to determine whether the corresponding levels are compatible.

[0128] The hierarchy of DRX levels may be configured in any suitable arrangement. The hierarchy of DRX levels may be configured such that the terminal device 110-A can act as an anchor for another terminal device 110-T at a higher or equal level within the hierarchy. In some examples, the hierarchy of DRX levels may be configured such that a higher DRX level has a longer sleep duration than a lower DRX level. This means that the terminal device 110-A can act as an anchor for another terminal device 110-T with a longer sleep duration. Other rules or procedures may be used to enable the terminal device 110-A to act as an anchor for another terminal device 110-T with a different DRX configuration. The rules or procedures may be based on the sleep duration, UE type, or any other suitable parameter. The rules or procedures do not need to be based on the hierarchy.

[0129] The DRX level may be determined by any suitable parameter or group of parameters. In some examples, the DRX level may have a predefined sleep cycle. In this case, different DRX levels may have different sleep cycles. In some examples, the DRX level may be specific to the type of the terminal device 110. In this case, an indication of the type of the terminal device 110 may thus act as an indication of the DRX level.

[0130] In some examples, the DRX level may have a specific timing for the wake-up signal, a specific signature for the wake-up signal, or any other suitable characteristic associated with the wake-up signal. The signature in the wake-up signal may be a waveform type, a code, or any other identifying characteristic. When the terminal device 110-A is listening for the wake-up signal, the terminal device 110-A may listen for the wake-up signal with a specific signature or characteristic.

[0131] Figure 5 Another example method is shown. Figure 5 The method may be implemented by a terminal device, such as the target UE 110-1 or any other suitable type of device or apparatus.

[0132] At block 500, the method includes causing a transmission wake-up signal to be sent. The wake-up signal includes an indication of the DRX level of the terminal device 110-1. The wake-up signal may include a signature specific to the DRX level. The signature may include a waveform type, a code, or any other identifying feature. In some examples, the wake-up signal may include a payload. In such a case, the payload may include information indicating the DRX level.

[0133] The wake-up signal may further include an indication of a sidelink positioning request. The wake-up signal may include a wake-up signal for SL positioning (WUSP) or any other suitable type of signal.

[0134] The wake-up signal may be a point-to-multipoint signal. The wake-up signal may be sent to one or more candidate terminal devices 110-A. The candidate terminal device 110-A may be a candidate anchor. The wake-up signal may include a point-to-multipoint signal.

[0135] The wake-up signal may be sent following any suitable trigger event. In some examples, the wake-up signal may be sent following a sidelink positioning request from the application layer. In some examples, the sidelink positioning request may be received from an access and mobility management function (AMF) or any other suitable entity.

[0136] At block 502, the method includes collecting responses from candidate terminal devices 110-A having a suitable DRX level. The suitability of the DRX level of the candidate terminal device 110-A may be determined based on a DRX level hierarchy, device type, or any other suitable factor.

[0137] In some examples, the suitability of the DRX level may be determined based on whether there is a match between the DRX level of the terminal device 110-T and the DRX level of the candidate terminal device 110-A. For example, if the candidate terminal device 110-A has the same DRX level as the terminal device 110-T to be located, the candidate terminal device 110-A may be able to serve the SL positioning request.

[0138] In some examples, the suitability of a DRX level can be determined based on a DRX level hierarchy. In such a case, the hierarchy can be used to compare the DRX level of the terminal device 110-T and the DRX level of the candidate terminal device 110-A. The DRX level hierarchy can be configured in any suitable arrangement. The DRX level hierarchy can be configured such that the candidate terminal device 110-A can act as an anchor for the terminal device 110-T at a higher or the same level within the hierarchy. In some examples, the DRX level hierarchy can be configured such that a higher DRX level has a longer sleep duration than a lower DRX level. This means that the candidate terminal device 110-A can act as an anchor for the terminal device 110-T with a longer sleep duration.

[0139] The terminal device 110-T can be configured to select one or more candidate terminal devices 110-A from among the candidate terminal devices 110-A that have collected responses to be used as an anchor. The candidate terminal device 110-A can be selected based at least in part on the DRX level of the terminal device 110-T and the candidate terminal device 110-A. After the candidate terminal device 110-A has been selected, SL positioning can be deployed.

[0140] Figure 6 An example signal diagram that can be used in some implementations of the present disclosure is shown. The signal diagram shows signals that can be sent between a candidate anchor UE 110-A and multiple different target UEs 110-T1, 110-T2, 110-T3.

[0141] The different target UEs 110 can have different DRX levels. The different DRX levels can be defined by any suitable characteristics. In some examples, the DRX levels can be defined by different sleep cycles or on / off durations, requirements for listening for WUSP in the same level or corresponding levels, or any other relevant characteristics. In Figure 6 the example, the first target UE 110-T1 has a DRX level 1, the second target UE 110-T2 has a DRX level 2, and the second target UE 110-T3 has a third DRX level. Other numbers and arrangements of target UEs 110 and DRX levels can be used in the examples of the present disclosure.

[0142] In Figure 6 the example, the candidate anchor UE 110-A is monitoring wake-up signals from the target UE 110-T with a suitable level. In this example, the level hierarchy is used to determine whether the candidate anchor has a DRX level suitable for the target UE 110.

[0143] The hierarchical structure enables interaction between UEs 110 with different levels. The hierarchical structure is configured such that a candidate anchor UE 110-A with a DRX level k monitors the WUSP from a target UE 110-T with a level j, where j ≥ k. The hierarchical structure of DRX levels can be configured such that higher DRX levels have longer sleep durations than lower DRX levels. This enables the candidate anchor UE 110-A to act as an anchor for a target UE 110-T with a DRX equal to or higher than its own.

[0144] The DRX level defined for SL positioning can be denoted as the DRXP level.

[0145] Examples of different DRXP levels can be:

[0146] Reduced-capacity (RedCap) UEs comply with a DRXP cycle with the pattern DRXP-type-RedCap.

[0147] Low-power high-accuracy positioning (LPHAP) UEs comply with a DRXP cycle with the pattern DRXP-type-LPHAP.

[0148] …

[0149] All other types of UEs comply with a DRXP cycle with the pattern DRXP-type-Gen.

[0150] In this case, the general level will be the lower level, and the RedCap level will be the higher level. Using the hierarchical structure, a candidate anchor UE 110-A with DRXP-type-Gen will be able to serve requests from a target UE 110-T with DRXP-type-RedCap or DRXP-type-LPHAP. However, a candidate anchor UE 110-A with DRXP-type-LPHAP will only be able to serve requests from a target UE 110-T that also has DRXP-type-LPHAP. Such a candidate anchor UE 110-A will not be able to serve requests from a target UE 110-T with DRXP-type-Gen or DRXP-type-LPHAP.

[0151] The corresponding DRX or DRXP level can be defined such that for a UE 110 of level J:

[0152] - has an on duration of on(j) seconds,

[0153] - has an off duration of off(j) seconds,

[0154] - It can send a WUSP with signature (j) – if it needs to become an SL target.

[0155] - It should listen for and attempt to detect all WUSPs with signature (k), where k >= j.

[0156] Therefore:

[0157] 1. For DRXP level 1, UE 110 has:

[0158] a. Level 1 specific opening and closing durations

[0159] b. It can perform the transmission of a WUSP with signature 1, where the signature can include waveform type, bandwidth, carrier frequency, code, modulation scheme, signal duration, or any other suitable characteristics.

[0160] c. It should listen for and attempt to detect the reception of WUSPs whose signatures are from the list L - level 1 = {signature 1, signature 2, signature 3,..., signature N}.

[0161] 2. For DRXP level 2, UE 110 has:

[0162] a. Level 2 specific opening and closing durations

[0163] b. It can perform the transmission of a WUSP with signature 2, where the signature can include waveform type, bandwidth, carrier frequency, code, modulation scheme, signal duration, or any other suitable characteristics.

[0164] c. It should listen for and attempt to detect the reception of WUSPs whose signatures are from the list L - level 2 = {signature 2, signature 3,..., signature N}.

[0165] 3…

[0166] 4. For DRXP level DRXP level N with level N specific opening and closing durations, UE 110 has:

[0167] a. Level N specific opening and closing durations

[0168] b. It can perform the transmission of a WUSP with a signature, where the signature can include waveform type, bandwidth, carrier frequency, code, modulation scheme, signal duration, or any other suitable characteristics.

[0169] c. It should listen for and attempt to detect the reception of WUSPs whose signatures are from the list L - level N = {signature N}.

[0170] In some examples, the DRX or DRXP level can also be defined relative to the UE type. In this case, different types of UEs will be associated with different DRX or DRXP levels. In this case, the DRX or DRXP level can have an attribute specifying the (multiple) UE types associated with that level.

[0171] The use of the DRX or DRXP level, and the level hierarchy, can ensure sufficient availability of the anchor UE 110-A to serve SL positioning requests from the target UE 110. The level hierarchy enables candidate anchor UEs 110-A with different DRX or DRXP levels from the target UE 110-T to wake up and serve the target UE 110-T.

[0172] In Figure 6 In the example of, at block 600, the target UEs 110-T1, 110-T2, 110-T3 send wake-up signals. In this example, the wake-up signal can be a WUSP signal.

[0173] The WUSP signal can be a point-to-multipoint (or broadcast) wake-up signal for SL positioning. The WUSP signal is intended to wake up candidate anchor UEs 110-A.

[0174] The WUSP signal can be level-based, such that the WUSP signal can include an indication of the DRX level or DRXP level of the target UE 110-T that has sent the WUSP signal.

[0175] In Figure 6 In the example of, the WUSP sent by the first target UE 110-T1 includes an indication of DRX level 1, the WUSP sent by the second target UE 110-T2 includes an indication of DRX level 2, and the WUSP sent by the third target UE 110-T3 includes an indication of DRX level 3.

[0176] In some examples, the WUSP can include an SL positioning request. In some examples, the SL positioning request can be sent separately. When the candidate anchor UE 110-A detects a WUSP of an appropriate level, the candidate anchor UE 110-A will monitor the next DRX on-duration for the SL positioning request. If the DRX level hierarchy is used, the appropriate level of WUSP will be one in level j, where j ≥ k, and k is the level of the candidate anchor UE 110-A. The use of the indication of the DRX or DRXP level in the WUSP helps avoid unnecessary wake-ups during the next on-duration.

[0177] At block 602, candidate anchor UE 110-A detects a WUSPS. The candidate anchor UE 110-A may evaluate the corresponding DRX level to determine whether the candidate anchor UE 110-A can serve SL positioning requests from target UE 110 that has sent a WUSP.

[0178] In Figure 6 the example, candidate anchor UE 110-A has level 1 and can serve all target UEs 110-T1, 110-T2, 110-T3 that have level 1 or higher. In this example, candidate anchor UE 110-A determines the order in which the corresponding UEs 110-T will be served. In this case, candidate anchor UE 110-A first determines to serve the first UE 110-T1, then the second UE 110-T2, and then the third UE 110-T3. In different scenarios, candidate anchor UE 110-A may determine a different order. For example, if candidate anchor UE 110-A determines that it has already assisted the first target UE 110-T (e.g., if a target UE 110-T in the same level has recently requested SL positioning support), then candidate anchor UE 110-A may first determine to serve the second target UE 110-T2.

[0179] After the candidate anchor UE 110-A has determined the order in which the positioning requests will be served, then at block 604, the candidate anchor UE 110-A replies to the first target UE 110-T1 with a positive acknowledgment and replies to the second target UE 110-T2 and the third target UE 110-T3 with a conditional acknowledgment.

[0180] At block 606, the first target UE 110-T1 responds to the positive acknowledgment by deploying an SL positioning session. At block 608, the second target UE 110-T2 responds to the positive acknowledgment by deploying a delayed SL positioning session. At block 610, instead of deploying an SL positioning session, the third target UE 110-T3 may cancel the request due to unacceptable latency.

[0181] As described above, in some examples, the DRX or DRXP level can be defined based on the type of the UE 110. For example, a specific type of target UE 110-T may have specific SL positioning requirements. For example, if the target UE 110-T is an industrial Internet of Things (IIoT) device, it may have a first set of requirements, while if the target UE 110-T is a vehicle, it may have a different set of requirements. The requirements for the IIoT device can be a target latency of 10 ms and a positioning accuracy within 1 m, while the requirements for the vehicle can be a target latency of 100 ms. In this case, the IIoT device can be configured with DRXP-type-IIoT, where the on-duration of DRXP-type-IIoT ensures that the relevant requirements of the IIoT device are met. Similarly, the vehicle can be configured with DRXP-type-V2X, where the on-duration of DRXP-type-V2X ensures that the relevant requirements of the vehicle are met.

[0182] Defining the DRX or DRXP level based on the type of the UE 110 can provide benefits that enable candidate anchor UEs 110-A with capabilities similar to those of the target UE 110-T to be woken up. For example, if the target UE 110-T is an IIoT terminal, it is beneficial for other IIoT UEs 110-A to act as anchors because they can be configured to perform similar functions. For example, they can process signals of similar bandwidths, implement the same positioning methods (such as RTT, AOD), and extract the same type of measurements (e.g., calculate the Rx-Tx time difference with the same granularity).

[0183] Figure 7 An example method is shown. Figure 7 The method can be implemented by a device, such as the candidate anchor UE 110-A. Figure 7 The method corresponds to Figure 6 the boxes 602 and 604 shown in

[0184] The candidate anchor UE 110-A has a DRX or DRXP level K. At block 700, the candidate anchor UE 110-A is configured in the DRX or DRXP off mode.

[0185] At block 702, the candidate anchor UE 110-A listens for WUSPs from one or more target UEs 110-T.

[0186] At block 704, the candidate anchor UE 110-A detects the WUSP signature. The signature of the WUSP includes a set of parameters that describe the generation and air transmission of the WUSP.

[0187] In some examples, the WUSP may include a raw reference signal. This may be referred to as raw-WUSP. The signature of raw-Wusp may include:

[0188] - Time-frequency duration / assignment:

[0189] o X consecutive orthogonal frequency division multiplexing (OFDM) symbols.

[0190] o Y frequency comb (i.e., every Yth subcarrier is occupied by a WUSP sample). o Codes such as a Zadoff-Chu code with root u and length N, a Gold code, a quadrature amplitude modulation (QAM) modulation order, or any other suitable code.

[0191] In some examples, the WUSP may include a payload signal. This may be referred to as payload-WUSP. The signature of payload-WUSP may include:

[0192] - A set of symbols reserved for reference signal transmission,

[0193] - A set of symbols for data transmission, where the payload includes at least information about rank and / or positioning requirements. The payload may be encoded using a known code (such as low-density parity-check (LDPC)) and modulated using a known modulation (such as 16QAM).

[0194] At block 706, the candidate anchor UE 110-A evaluates the DRX level or DRXP level of the detected WUSP signal. The level evaluation of the WUSP signal can determine whether the target UE 110-T has a level that can be served by the candidate anchor UE 110-A.

[0195] As an example, a candidate anchor UE 110-A with a DRX cycle of level K is configured to listen for WUSPs from a list L-level K = {signature K, signature K+1, …, signature N}. The signature can be the signature of any type of WUSP, such as raw-WUSP or payload-WUSP.

[0196] In an example where the DRX or DRXP level is specific to the UE type, the list will include only one element, as the candidate anchor UE 110-A will listen for WUSPs from a UE 110-T of the same type.

[0197] The candidate anchor UE 110-A can detect any one of the WUSPs of list L level K. If multiple WUSPs are detected, the candidate anchor UE 110-A will evaluate which SL positioning session it should join. Any suitable process can be used to evaluate which SL positioning session should be joined. For example, the candidate anchor UE 110-A can join the session associated with the WUSP of the closest level and conditionally join other sessions (conditioned on whether the session of the closest level is deployed).

[0198] At block 708, if a WUSP of the appropriate level is detected, the candidate anchor UE 110-A switches the configuration of the DRX or DRXP mode to on. At block 710, the candidate anchor UE 110-A accepts the SL positioning request, and at block 712, the candidate anchor UE 110-A notifies the target UE 110-T of the DRX or DRXP level of the candidate anchor UE 110-A.

[0199] Figure 8 Another example method is shown. Figure 8 The method can be implemented by a device, such as the target UE 110-T. The target UE 110-T can be Figure 6 any one of the target UEs 110-T shown in, or any other suitable target UE 110-T.

[0200] At block 800, the target UE 110-T receives an SL positioning request from the application layer of the network 100. The receipt of the SL positioning request triggers the wake-up of the target UE 110-T, such that at block 802, the target UE 110-T is configured in the DRX or DRXP on mode. This enables the target UE 110-T to send a WUSP.

[0201] In this example, the target UE 110-T has a DRX or DRXP level J. After the target UE 110-T has switched to the on mode, at block 804, the target UE 110-T sends a WUSP. The WUSP includes a signature of level J.

[0202] After the WUSP has been sent, the target UE 110-T listens for a response from the candidate anchor UE 110-A. The target UE 110-T can collect the responses received during the listening window. Responses will be received from candidate anchor UEs 110-A with the appropriate level. Responses can be received from candidate anchor UEs 110-A with level k ≤ j.

[0203] At block 808, the target UE 110-T selects an anchor from a list of candidate anchors 110-A. Any suitable criteria can be used to select the anchor to be used. For example, it can be selected based on power saving requirements.

[0204] At block 810, the target UE 110 uses the selected anchor to initiate SL positioning.

[0205] Figure 9 An example of the controller 900 is illustrated. The controller 900 can be provided within a terminal device such as the UE 100. The implementation of the controller 900 can be controller circuitry. The controller 900 can be implemented separately in hardware, with certain aspects of software including firmware alone, or can be a combination of hardware and software (including firmware).

[0206] As Figure 9 shown, the controller 900 can be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program in a general-purpose or special-purpose processor 902 (which are stored on a computer-readable storage medium (such as a disk, memory, etc.)) and executed by such a processor 902.

[0207] The processor 902 is configured to read from and write to the memory 904. The processor 902 can also include an output interface and an input interface, and the processor 902 outputs data and / or commands via the output interface, and data and / or commands are input into the processor 902 via the input interface.

[0208] The memory 904 stores a computer program including computer program instructions 906 (computer program code), and the computer program instructions 906 control the operation of the device when loaded into the processor 902. The computer program instructions 906 of the computer program provide the logic and routines that enable the device to execute the methods illustrated in the drawings. By reading the memory 904, the processor 902 can load and execute the computer program.

[0209] In an example where the controller 900 is provided within a device for providing the anchoring capability 110-A, the controller 900 includes: at least one processor 902; and at least one memory 904, at least one memory 904 storing instructions that, when executed by the at least one processor 902, cause the device to at least perform:

[0210] Detecting 400 a wake-up signal in a discontinuous reception (DRX) off mode, where the wake-up signal is sent from another terminal device and the wake-up signal includes an indication of the DRX level of the other terminal device; and

[0211] Based on the DRX level indicated in the wake-up signal, support the positioning of another terminal device 402.

[0212] In an example where the controller 900 is provided within the device 110-T to be positioned, the controller 900 includes: at least one processor 902; and at least one memory 904, at least one memory 904 storing instructions, which when executed by the at least one processor 902, cause the device to at least perform:

[0213] Cause a wake-up signal 500 to be transmitted to one or more candidate terminal devices, the wake-up signal including an indication of the discontinuous reception (DRX) level of the terminal device; and

[0214] Collect 502 responses from the candidate terminal devices that have a suitable DRX level, where the suitability of the DRX level is determined based on a DRX level hierarchy.

[0215] The instructions 906 can reach the UE 110 via any suitable delivery mechanism 908. The delivery mechanism 908 can be, for example, a machine-readable medium, a computer-readable medium, a non-transitory computer-readable storage medium, a computer program product, a memory device, a recording medium such as a compact disc read-only memory (CD-ROM) or a digital versatile disc (DVD) or a solid-state memory, an article of manufacture including or tangibly embodying the instructions 906. The delivery mechanism can be a signal configured to reliably transmit the instructions 906. The device can propagate or transmit the instructions 906 as a computer data signal. The instructions 906 can include computer code or software code.

[0216] The computer program can include computer program instructions 906 for causing the UE 110 to perform at least the following or for performing at least the following:

[0217] Detect 400 a wake-up signal when in discontinuous reception (DRX) off mode, where the wake-up signal is sent from another terminal device and the wake-up signal includes an indication of the DRX level of the other terminal device; and

[0218] Based on the DRX level indicated in the wake-up signal, support the positioning of another terminal device 402.

[0219] The computer program can include computer program instructions 906 for causing the UE 110 to perform at least the following or for performing at least the following:

[0220] Cause a wake-up signal 500 to be transmitted to one or more candidate terminal devices, the wake-up signal including an indication of the discontinuous reception (DRX) level of the terminal device; and

[0221] Collect 502 responses from candidate terminal devices having suitable DRX levels, where the suitability of the DRX levels is determined based on a DRX level hierarchy.

[0222] Computer program instructions may be included in a computer program, a non-transitory computer-readable medium, a computer program product, a machine-readable medium. In some but not necessarily all examples, the computer program instructions may be distributed over more than one computer program.

[0223] Although the memory 904 is shown as a single component / circuitry, it may be implemented as one or more separate components / circuitry, some or all of the one or more separate components / circuitry may be integrated / removable and / or may provide permanent / semi-permanent / dynamic / cache storage.

[0224] Although the processor 902 is shown as a single component / circuitry, it may be implemented as one or more separate components / circuitry, some or all of the one or more separate components / circuitry may be integrated / removable. The processor 902 may be a single-core or multi-core processor.

[0225] References to "computer-readable storage medium", "computer program product", "tangibly embodied computer program", etc., or "controller", "computer", "processor", etc., should be understood to include not only computers having different architectures, such as single / multi-processor architectures and sequential (Von Neumann) / parallel architectures, but also dedicated circuits, such as field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), signal processing devices, and other processing circuitry. References to computer programs, instructions, code, etc., should be understood to include software or firmware for programmable processors, such as programmable content for hardware devices, whether instructions for a processor or configuration settings for fixed function devices, gate arrays, or programmable logic devices, etc.

[0226] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0227] (a) Only hardware circuitry implementations (such as only implementations in analog and / or digital circuitry), and

[0228] (b) Combinations of hardware circuitry and software, such as (where applicable):

[0229] (i) Combinations of (multiple) analog and / or digital hardware circuitry with software / firmware, and

[0230] (ii) any part of one or more hardware processors having software (including one or more digital signal processors), software, and one or more memories, which work together to cause a device, such as a mobile phone or a server, to perform various functions; and

[0231] (c) one or more hardware circuits and one or more processors, such as one or more microprocessors or a part of one or more microprocessors, the operation of which requires software (such as firmware), but the software may be absent when not needed for operation.

[0232] This definition of circuitry applies to all uses of the term in this application, including in any claim. As another example, as used in this application, the term circuitry also encompasses implementations of only hardware circuits or processors and their (or its) attendant software and / or firmware. For example, if applicable to a particular claim element, the term "circuitry" also encompasses a baseband integrated circuit for a mobile device, or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

[0233] Figures 3 to 8 The stages illustrated therein may represent steps in a method and / or sections of code in a computer program. The illustration of a particular order of boxes does not necessarily imply a required or preferred order for the boxes, and the order and arrangement of the boxes may vary. Additionally, it may be possible to omit some boxes.

[0234] Where a structural feature has been described, that structural feature may be replaced by a component for performing one or more of the functions of that structural feature, whether or not those functions are explicitly or implicitly described.

[0235] The term "comprising" is used in this document in an inclusive rather than an exclusive sense. That is, any reference to X that comprises Y indicates that X may include only one Y or may include more than one Y. If an exclusive meaning of "comprising" is intended, it will be made clear in the context by referring to "comprising only one" or by using "consisting of".

[0236] In this specification, the terms "connected", "coupled", and "communicating" and their derivatives mean operably connected / coupled / communicating. It should be understood that any number or combination of intervening components (including no intervening components) may exist, i.e., so as to provide a direct or indirect connection / coupling / communication. Any such intervening component may include hardware and / or software components.

[0237] As used herein, the term "determine / determining" (and its grammatical variants) can include, but is not limited to: calculating, computing, processing, deriving, measuring, investigating, identifying, looking up (e.g., looking up in a table, database, or other data structure), ascertaining, etc. Moreover, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), obtaining, etc. Moreover, "determine / determining" can include parsing, selecting, choosing, establishing, etc.

[0238] In this specification, various examples are referred to. The description of a feature or function related to an example indicates that these features or functions exist in that example. The use of the terms "example", "for example", "can", or "may" in the text means that, whether explicitly stated or not, these features or functions exist at least in the described example, whether described as an example or not, and they can (but not necessarily) exist in some or all other examples. Thus, "example", "for example", "can", or "may" refer to a particular instance in a class of examples. The attributes of an instance can be just the attributes of that instance, or the attributes of the class, or the attributes of a subclass of the class that includes some, but not all, of the instances in the class. Thus, it is implicitly disclosed that features described with reference to one example rather than another can, where possible, be used as part of a working combination in other examples, but do not necessarily have to be used in other examples.

[0239] Although some examples have been described in the previous paragraphs with reference to various examples, it should be understood that the given examples can be modified without departing from the scope of the claims.

[0240] The features described in the previous specification can be used in combinations other than those explicitly described above.

[0241] Although functions have been described with reference to certain features, these functions can be performed by other features, whether described or not.

[0242] Although features have been described with reference to certain examples, these features can also appear in other examples, whether described or not.

[0243] In this document, the use of the terms "a", "an", or "the" has an inclusive rather than an exclusive meaning. That is, any reference to X that includes a / an / the Y indicates that X can include only one Y, or can include more than one Y, unless the context clearly indicates the contrary. If an exclusive meaning for "a", "an", or "the" is intended, this will be made clear in the context. In some cases, the use of "at least one" or "one or more" can be used to emphasize the inclusive meaning, but the absence of these terms should not be taken as inferring any exclusive meaning.

[0244] The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and to features (equivalent features) that achieve substantially the same technical effect. Equivalent features include, for example, features that are variants and that achieve substantially the same result in substantially the same way. Equivalent features include, for example, features that perform substantially the same function in substantially the same way to achieve substantially the same result.

[0245] In this specification, various examples have been referred to using adjectives or adjective phrases to describe the features of the examples. Such a description of a characteristic associated with an example indicates that the characteristic is present in some examples exactly as described, and in other examples substantially as described.

[0246] The above specification describes some examples of the present disclosure. However, those of ordinary skill in the art will recognize possible alternative structural and method features that provide functions equivalent to the specific examples of such structures and features described above, and for the sake of brevity and clarity, these structures and features have been omitted from the above description. However, the above description should be construed as implicitly including a reference to such alternative structural and method features that provide equivalent functions, unless such alternative structural or method features are explicitly excluded in the above description of the examples of the present disclosure.

[0247] Although efforts have been made in the above specification to draw attention to those features considered important, it should be understood that the applicant may seek protection by means of claims directed to any patentable feature or combination of features mentioned above and / or shown in the figures, whether or not such features are emphasized.

Claims

1. A terminal device, comprising components for: Detecting a wake-up signal when in a discontinuous reception (DRX) off mode, where the wake-up signal is sent from another terminal device and the wake-up signal includes an indication of the DRX level of the other terminal device; and Supporting the positioning of the other terminal device based on the DRX level indicated in the wake-up signal.

2. The terminal device according to claim 1, wherein the wake-up signal includes an indication of a sidelink positioning request.

3. The terminal device according to any one of the preceding claims, wherein supporting the positioning of the other terminal device Comprises: Determining whether the positioning request from the other terminal device will be served by the terminal device, where the positioning request is associated with sidelink signaling between the terminal device and the other terminal device.

4. The terminal device according to claim 3, wherein the component is for determining how a sidelink positioning request can be served.

5. The terminal device according to any one of claims 3 to 4, wherein the component is for controlling whether the DRX mode of the terminal device is on or off based on determining whether the sidelink positioning request can be served by the terminal device.

6. The terminal device according to any one of claims 3 to 5, wherein the component is for switching the terminal device to a DRX on mode if it is determined that the sidelink positioning request can be served by the terminal device.

7. The terminal device according to claim 6, wherein the component is for causing the transmission of a message indicating that the sidelink positioning request can be accepted, where the message includes an indication of the DRX level of the terminal device.

8. The terminal device according to any one of claims 3 to 7, wherein the component is for maintaining the terminal device in the DRX off mode if it is determined that the sidelink positioning request cannot be served by the terminal device.

9. The terminal device according to any one of the preceding claims, wherein the support for the positioning is based on a DRX level hierarchy.

10. The terminal device according to any one of the preceding claims, wherein the DRX level hierarchy is configured such that a terminal device can act as an anchor for another terminal device of a higher or equal level.

11. The terminal device according to claim 9, wherein the DRX level hierarchy is configured such that a higher DRX level has a longer sleep duration than a lower DRX level.

12. The terminal device according to any one of the preceding claims, wherein the DRX level has a predefined sleep cycle.

13. The terminal device according to any one of the preceding claims, wherein the DRX level is specific to the type of terminal device.

14. The terminal device according to any one of the preceding claims, wherein the DRX level has at least one of the following: a specific timing of the wake-up signal, a specific signature of the wake-up signal.

15. The terminal device according to any one of the preceding claims, wherein the component is for providing an anchoring ability.

16. A method, Comprising: Detect a wake-up signal when in a discontinuous reception (DRX) off mode, where the wake-up signal is sent from another terminal device, and the wake-up signal includes an indication of the DRX level of the other terminal device; and Based on the DRX level indicated in the wake-up signal, support the positioning of the other terminal device.

17. A computer program comprising instructions that, when executed by a processor, cause a terminal device to at least perform: Detect a wake-up signal when in a discontinuous reception (DRX) off mode, where the wake-up signal is sent from another terminal device, and the wake-up signal includes an indication of the DRX level of the other terminal device; and Based on the DRX level indicated in the wake-up signal, support the positioning of the other terminal device.

18. A terminal device comprising components for: Causing a wake-up signal to be transmitted to one or more candidate terminal devices, the wake-up signal including an indication of the discontinuous reception (DRX) level of the terminal device; and Collecting responses from candidate terminal devices having a suitable DRX level, where the suitability of the DRX level is determined based on a DRX level hierarchy.

19. The terminal device according to claim 18, wherein the wake-up signal includes an indication of a sidelink positioning request.

20. The terminal device according to any one of claims 18 to 19, wherein the suitable DRX level includes a matching DRX level.

21. The terminal device according to any one of claims 18 to 20, wherein the wake-up signal is sent after a sidelink positioning request from an application.

22. The terminal device according to any one of claims 18 to 21, wherein the components are for selecting one or more candidate terminal devices from the candidate terminal devices at least partially based on the DRX level.

23. The terminal device according to any one of claims 18 to 22, wherein the wake-up signal includes a point-to-multipoint signal.

24. A method comprising: Causing a wake-up signal to be transmitted to one or more candidate terminal devices, the wake-up signal including an indication of the discontinuous reception (DRX) level of the terminal device; and Collecting responses from candidate terminal devices having a suitable DRX level, where the suitability of the DRX level is determined based on a DRX level hierarchy.

25. A computer program comprising instructions that, when executed by a processor, cause a terminal device to at least perform: Causing a wake-up signal to be transmitted to one or more candidate terminal devices, the wake-up signal including an indication of the discontinuous reception (DRX) level of the terminal device; and Collecting responses from candidate terminal devices having a suitable DRX level, where the suitability of the DRX level is determined based on a DRX level hierarchy.

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