WO2023143709A1

WO2023143709A1 - Enabling rrc status information for enhanced positioning

Info

Publication number: WO2023143709A1
Application number: PCT/EP2022/051723
Authority: WO
Inventors: Muhammad Ikram ASHRAF; Timo Koskela; Diomidis Michalopoulos; Mikko SÄILY
Original assignee: Nokia Technologies Oy
Priority date: 2022-01-26
Filing date: 2022-01-26
Publication date: 2023-08-03
Also published as: CN118715834A

Abstract

Improved techniques for obtaining locations of UEs in a wireless network include, in response to a positioning request to determine a position of at least one UE in a wireless network (210), an LMF requests (220) RRC state from an AMF and, if the RRC state is RRC INACTIVE or RRCIDLE, the LMF provides (240) last-known location of the at least one UE to AMF for paging. Advantageously, the improved techniques may reduce latency and resource overhead, i.e. signaling overhead. This is particularly useful when the positioning estimation procedures needs to run for the UEs which are not in RRCCONNECTED state. Moreover, the LMF avoids initiating any positioning procedure if the UE is in RRC INACTIVE or RRC IDLE state. Furthermore, if the UE RRC status is not RRC CONNECTED, the LMF assists the AMF by providing the last known location to discover the UE.

Description

ENABLING RRC STATUS INFORMATION FOR ENHANCED POSITIONING

TECHNICAL FIELD

[0001] This description relates to wireless communications.

BACKGROUND

[0002] A communication system may be a facility that enables communication between two or more nodes or devices, such as fixed or mobile communication devices. Signals can be carried on wired or wireless carriers.

[0003] An example of a cellular communication system is an architecture that is being standardized by the 3^rd Generation Partnership Project (3GPP). A recent development in this field is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. E-UTRA (evolved UMTS Terrestrial Radio Access) is the air interface of 3GPP's Long Term Evolution (LTE) upgrade path for mobile networks. In LTE, base stations or access points (APs), which are referred to as enhanced Node AP (eNBs), provide wireless access within a coverage area or cell. In LTE, mobile devices, or mobile stations are referred to as user equipments (UE). LTE has included a number of improvements or developments. Aspects of LTE are also continuing to improve.

[0004] 5G New Radio (NR) development is part of a continued mobile broadband evolution process to meet the requirements of 5G, similar to earlier evolution of 3G & 4G wireless networks. In addition, 5G is also targeted at the new emerging use cases in addition to mobile broadband. A goal of 5G is to provide significant improvement in wireless performance, which may include new levels of data rate, latency, reliability, and security. 5G NR may also scale to efficiently connect the massive Internet of Things (loT) and may offer new types of mission-critical services. For example, ultra-reliable and low-latency communications (URLLC) devices may require high reliability and very low latency.

SUMMARY

[0005] According to an example embodiment, a method may include: controlling receiving, by a location management unit associated with a wireless network from an access and mobility management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network; in response to receiving the request to determine the location of the at least one user device, controlling transmitting, by the location management unit to the access and mobility management unit, a request to provide radio resource control status information of the at least one user device; controlling receiving, by the location management unit from the access and mobility management unit, the radio resource control status information of the at least one user device; and in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control transmitting, to the access and mobility management unit, a previously estimated position of the one or more user devices of the at least one user device to cause the access and mobility management unit to trigger a radio resource control status change to an active mode for at least one user device in the vicinity of the previously estimated position to enable the location management unit to obtain the location of the user device within the wireless network.

[0006] According to an example embodiment, a method may include controlling transmitting, by an access and mobility management unit associated with a wireless network to location management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network; controlling receiving, by the access and mobility management unit from the location management unit, a request to provide radio resource control status information of the at least one user device; controlling transmitting, by the access and mobility management unit to the location management unit, the radio resource control status information of the at least one user device; in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control receiving, from the location management unit, a previously estimated position of the one or more user devices of the at least one user device; and control transmitting, to the wireless network, a request to a radio resource control status change to an active mode for at least one user device in the vicinity of the previously estimated position for determining the requested location .

[0007] Other example embodiments are provided or described for each of the example methods, including: means for performing any of the example methods; a non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, are configured to cause a computing system to perform any of the example methods; and an apparatus including at least one processor, and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform any of the example methods.

[0008] The details of one or more examples of embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a block diagram of a wireless network according to an example embodiment.

[0010] FIG. 2 is a flow chart illustrating operation of a location management unit (or LMF).

[0011] FIG. 3 is a flow chart illustrating operation of an access and mobility management unit (or AMF).

[0012] FIG. 4 is a diagram illustrating an example positioning architecture applicable to NG-RAM.

[0013] FIG. 5 is a signaling diagram illustrating an example setup of a timer for RRC status communication, according to FIGs. 2-3.

[0014] FIG. 6 is a flow chart illustrating operation of a LMF with regard to timer-based RRC status communication, according to FIGs. 2-3.

[0015] FIG. 7 is a flow chart illustrating operation of an AMF with regard to timer-based RRC status communication, according to FIGs. 2-3.

[0016] FIG. 8 is a signaling diagram illustrating a positioning scheme performed according to FIGs. 2-3.

[0017] FIG. 9 is a block diagram of a wireless station or node (e.g., network node, user node or UE, relay node, or other node).

DETAILED DESCRIPTION

[0018] FIG. 1 is a block diagram of a wireless network 130 according to an example embodiment. In the wireless network 130 of FIG. 1, user devices 131, 132, and 133, which may also be referred to as mobile stations (MSs) or user equipment (UEs), may be connected (and in communication) with a base station (BS) 134, which may also be referred to as an access point (AP), an enhanced Node B (eNB), a gNB or a network node. The terms user device and user equipment (UE) may be used interchangeably. A BS may also include or may be referred to as a RAN (radio access network) node, and may include a portion of a BS or a portion of a RAN node, such as (e.g., such as a centralized unit (CU) and/or a distributed unit (DU) in the case of a split BS or split gNB). At least part of the functionalities of a BS (e.g., access point (AP), base station (BS) or (e)Node B (eNB), gNB, RAN node) may also be carried out by any node, server or host which may be operably coupled to a transceiver, such as a remote radio head. BS (or AP) 134 provides wireless coverage within a cell 135, including to user devices (or UEs) 131, 132, and 133. Although only three user devices (or UEs) are shown as being connected or attached to BS 134, any number of user devices may be provided. BS 134 is also connected to a core network 150 via a SI interface 151. This is merely one simple example of a wireless network, and others may be used.

[0019] A base station (e.g., such as BS 134) is an example of a radio access network (RAN) node within a wireless network. A BS (or a RAN node) may be or may include (or may alternatively be referred to as), e.g., an access point (AP), a gNB, an eNB, or portion thereof (such as a /centralized unit (CU) and/or a distributed unit (DU) in the case of a split BS or split gNB), or other network node.

[0020] According to an illustrative example, a BS node (e.g., BS, eNB, gNB, CU/DU, ... ) or a radio access network (RAN) may be part of a mobile telecommunication system. A RAN (radio access network) may include one or more BSs or RAN nodes that implement a radio access technology, e.g., to allow one or more UEs to have access to a network or core network. Thus, for example, the RAN (RAN nodes, such as BSs or gNBs) may reside between one or more user devices or UEs and a core network. According to an example embodiment, each RAN node (e.g., BS, eNB, gNB, CU/DU, ... ) or BS may provide one or more wireless communication services for one or more UEs or user devices, e.g., to allow the UEs to have wireless access to a network, via the RAN node. Each RAN node or BS may perform or provide wireless communication services, e.g., such as allowing UEs or user devices to establish a wireless connection to the RAN node, and sending data to and/or receiving data from one or more of the UEs. For example, after establishing a connection to a UE, a RAN node or network node (e.g., BS, eNB, gNB, CU/DU, ... ) may forward data to the UE that is received from a network or the core network, and/or forward data received from the UE to the network or core network. RAN nodes or network nodes (e.g., BS, eNB, gNB, CU/DU, ... ) may perform a wide variety of other wireless functions or services, e.g., such as broadcasting control information (e.g., such as system information or on-demand system information) to UEs, paging UEs when there is data to be delivered to the UE, assisting in handover of a UE between cells, scheduling of resources for uplink data transmission from the UE(s) and downlink data transmission to UE(s), sending control information to configure one or more UEs, and the like. These are a few examples of one or more functions that a RAN node or BS may perform.

[0021] A user device or user node (user terminal, user equipment (UE), mobile terminal, handheld wireless device, etc.) may refer to a portable computing device that includes wireless mobile communication devices operating either with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station (MS), a mobile phone, a cell phone, a smartphone, a personal digital assistant (PDA), a handset, a device using a wireless modem (alarm or measurement device, etc.), a laptop and/or touch screen computer, a tablet, a phablet, a game console, a notebook, a vehicle, a sensor, and a multimedia device, as examples, or any other wireless device. It should be appreciated that a user device may also be (or may include) a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network. Also, a user node may include a user equipment (UE), a user device, a user terminal, a mobile terminal, a mobile station, a mobile node, a subscriber device, a subscriber node, a subscriber terminal, or other user node. For example, a user node may be used for wireless communications with one or more network nodes (e.g., gNB, eNB, BS, AP, DU, CU/DU) and/or with one or more other user nodes, regardless of the technology or radio access technology (RAT). In LTE (as an illustrative example), core network 150 may be referred to as Evolved Packet Core (EPC), which may include a mobility management entity (MME) which may handle or assist with mobility/handover of user devices between BSs, one or more gateways that may forward data and control signals between the BSs and packet data networks or the Internet, and other control functions or blocks. The protocol running between UE and CN is non-access stratum (NAS) protocols. Other types of wireless networks, such as 5G (which may be referred to as New Radio (NR)) may also include a core network. Generally the 5G core architecture is similar to 4G core but 5G core gained some new capabilities and functions. One of the most significant difference between 4G and 5G core is the separation of control and use plane functions from each other. For instance, access and mobility management function (AMF) supports e.g., termination of NAS signaling, connection management, mobility management, etc. In 5G AMF works as a part of MME (4G core) and responsible to establish NAS signaling connection with UE and helps UE to register.

[0022] In addition, the techniques described herein may be applied to various types of user devices or data service types, or may apply to user devices that may have multiple applications running thereon that may be of different data service types. New Radio (5G) development may support a number of different applications or a number of different data service types, such as for example: machine type communications (MTC), enhanced machine type communication (eMTC), Internet of Things (loT), and/or narrowband loT user devices, enhanced mobile broadband (eMBB), and ultra-reliable and low-latency communications (URLLC). Many of these new 5G (NR) - related applications may require generally higher performance than previous wireless networks.

[0023] loT may refer to an ever-growing group of objects that may have Internet or network connectivity, so that these objects may send information to and receive information from other network devices. For example, many sensor type applications or devices may monitor a physical condition or a status, and may send a report to a server or other network device, e.g., when an event occurs. Machine Type Communications (MTC, or Machine to Machine communications) may, for example, be characterized by fully automatic data generation, exchange, processing and actuation among intelligent machines, with or without intervention of humans. Enhanced mobile broadband (eMBB) may support much higher data rates than currently available in LTE.

[0024] Ultra-reliable and low-latency communications (URLLC) is a new data service type, or new usage scenario, which may be supported for New Radio (5G) systems. This enables emerging new applications and services, such as industrial automations, autonomous driving, vehicular safety, e-health services, and so on. 3 GPP targets in providing connectivity with reliability corresponding to block error rate (BLER) of 10'⁵ and up to 1 ms U-Plane (user/data plane) latency, by way of illustrative example. Thus, for example, URLLC user devices/UEs may require a significantly lower block error rate than other types of user devices/UEs as well as low latency (with or without requirement for simultaneous high reliability). Thus, for example, a URLLC UE (or URLLC application on a UE) may require much shorter latency, as compared to a eMBB UE (or an eMBB application running on a UE).

[0025] The techniques described herein may be applied to a wide variety of wireless technologies or wireless networks, such as LTE, LTE-A, 5G (New Radio (NR)), cmWave, and/or mmWave band networks, loT, MTC, eMTC, eMBB, URLLC, etc., or any other wireless network or wireless technology. These example networks, technologies or data service types are provided only as illustrative examples.

[0026] In some cases, a UE positioning function may be used to determine a geographic position (or location) of a UE. In some cases, UE positioning may be performed or determined based on positioning reference signals (PRSs). For example, a positioning reference signal (PRS) may be a reference signal that may be transmitted and/or received that may be used to obtain positioning measurements and/or to allow a UE position to be determined or estimated. In some cases, a UE position (or UE position estimate) may be determined, for example, based on positioning measurements, such as a measured timing and/or measured received power (or other signal measurement) of one or more PRSs, for example. For example, PRSs may be or may include PRS sequences that may be pseudo-random sequences that have good (or relatively high) auto-correlation properties and small (or relatively low) cross-correlation properties, e.g., to allow timing or time differences of two signals to be determined.

[0027] In the case of downlink/uplink(DL/UL) positioning (where PRS signals are communicated between a a network node or gNB and UE), PRS signals may include downlink (DL) PRS signals, SSB, CSI-RS, (transmitted by a gNB or other network node to a UE), or uplink (UL) PRS, (positioning) SRS, and SSB CSI-RS. (transmitted by a UE to a gNB or network node).

[0028] In DL/UL-based positioning, the centralized positioning function/entity, referred to as a Location Management Function (LMF) in 5G NR, is the entity that coordinates the positioning services (positioning session) among UE(s) and gNB(s). By taking into account the capability of UEs, the LMF determines a positioning configuration, e.g., such as which positioning method to be used, a configuration of gNBs and UEs for transmitting/receiving reference signals in DL/UL for positioning, and performing positioning measurements and calculating a position estimate of a UE based on the positioning measurements. Further, again based on UE capabilities, the LMF can determine whether the position estimates should be calculated by the UE or the LMF itself, based on the performed positioning measurements. Thus, for DL/UL positioning, the UE positioning process is controlled or coordinated by the network entity (e.g., LMF or other network entity or network node).

[0029] Accurate positioning estimates may be needed UE’s in wireless networks. NR positioning is introduced in 3 GPP Rel-16 for RRC CONNECTED state with regard to introduction of UE assisted DL and UL positioning methods, such as DL-TDOA, DL- AoD, multi-RTT, UL-RTOA, UL AoA and E-CID, and of UE based positioning methods. New positioning reference signals PRS, for downlink transmission, and SRS, for UL transmission, are specified and related measurement requirements for UE and gNB were defined including measurement accuracy requirements for UE and gNB.

[0030] In 3 GPP Rel-17, NR positioning enhancements are investigated in terms of timing error mitigation for timing-based methods to improve measurement accuracy, in terms of latency reduction to improve response time and applicability of positioning in RRC INACTIVE.

[0031] RRC INACTIVE state is used to reduce network signaling load as well as to reduce latency involved in transitioning to RRC CONNECTED state. Moreover, the UE in RRC INACTIVE state is allowed to behave similar way as in RRC IDLE state to save power.

[0032] Similar to RRC IDLE, the UE is in a kind of sleep mode and wakes up periodically (according to a configured DRX cycle) and monitors for paging messages from the network. The network can reach UEs in RRC INACTIVE state through paging messages, and to notify UEs in RRC INACTIVE, change of system information and ETWS/CMAS indications through short Messages. Both paging messages and short Messages are addressed with P-RNTI on PDCCH, but while the former is sent on PCCH, the latter is sent over PDCCH directly.

[0033] In RRC INACTIVE state, the UE cannot transmit anything in the uplink except for PRACH as part of RA procedure initiated when UE desires to transit to RRC CONNECTED state (to transmit RRCResumeRequest) or to request for an on-demand system information.

[0034] Particularly for positioning use cases requiring low latency, to perform positioning measurement, UE needs to be in RRC CONNECTED state since latency involved to bring back the UE in the RRC CONNECTED state from RRC INACTIVE impact the positioning performance. Similarly, UE needs to successfully monitor the relevant paging occasion in order to perform positioning measurements. [0035] The importance of the RRC INACTIVE state problem in positioning has been highlighted in the Rel-17 WID: “Specify methods, measurements, signaling and procedures to support positioning for UEs in RRC_ INACTIVE state, for UE-based and UE-assisted positioning solutions, including [RAN2, RANI, RAN3, RAN4]:

• DL NR positioning methods and RAT-independent positioning methods, o Support of UE positioning measurements for UEs in

RRC INACTIVE state o Reporting of positioning measurement or location estimate performed in RRC INACTIVE when the UE is in RRC INACTIVE state.”

[0036] According to the RAN2-114e meeting the following agreement is made:

• Exposure of the RRC state of the UE to the LPP layer of the UE for RRC INACTIVE UL and DL positioning will not be specified.

• The RRC state of the UE is not exposed to the LMF for RRC INACTIVE UL and DL positioning.

[0037] FIG. 4 illustrates a UE positioning overall architecture 400 including an NL1 interface 435 between the LMF 430 and AMF 440. The NL1 interface 435 between the LMF 430 and the AMF 440 is transparent to all UE 410 related, gNB 424 related and ng-eNB 422 related positioning procedures within NG-RAN 420. It is used only as a transport link for the LIE Positioning Protocols LPP and NR Positioning Protocol A NRPPa. The NL1 reference point supports location requests for a target UE 410 sent from a serving AMF 440 for the target UE 410 to an LMF 440. Location requests are supported for immediate location and for deferred location for periodic or triggered location events.

[0038] The LMF provides various services and operations to consumers associated with the wireless network. One such service is Nlmf Location, with operation

Nlmf Location DetermineLocation (Request/Response); the consumer is the AMF. The detail of the Service Nlmf_Location is specified in TS 23.273 Section 8.3.2.2 as follows:

• Description: Provides UE location information to the consumer NF.

• Input, Required: Client Type, LCS Correlation Identifier.

• Input, Optional: serving cell identifierof the Primary Cell in the Master RAN node and the Primary Cell in the Secondary RAN node when available based on Dual Connectivity scenarios if the UE is using 3 GPP access, Location QoS, Supported GAD shapes, AMF identity if a UE associated Namf Communication service is to be invoked by LMF, Type of request for a 5GC-MO-LR, Embedded LPP message for a 5GC-M0- LR, subscribed assistance data for a 5GC-M0-LR, Deferred location type, Deferred location parameters, indication if UE supports LPP or not, Notification Target Address, Notification Correlation ID.

• Output, Required: Success/Failure indication.

• Output, Optional: Geodetic Location, Local Location including Coordinate ID, Civic Location, Position Methods Used (in the case of success indication provided), Serving LMF identification, Failure Cause (in the case of failure indication provided).

[0039] The access and mobility management function (AMF) also provides various services and operations to consumers associated with the wireless network. One such service is Namf Location, with operation Namf Location ProvidePositioninglnfo (Request/Response); the consumer is the Gateway Mobile Location Centre (GMLC), the network entity in the 5G Core Network (5GC) supporting Location Services (LCS).

[0040] As detailed in TS 23.273, Sections 4.3.7 and 4.3.8, respectively, the AMF and LMF support the following functions.

[0041] The functionalities of the AMF and the LMF and their role within a positioning session are as follows. The AMF contains functionality responsible for managing positioning for a target UE for all types of location request. The AMF is accessible to the GMLC and NEF via a Namf interface, to the RAN via the N2 reference point and to the UE via the N 1 reference point. Functions which may be performed by an AMF to support location services include the following:

• initiate an NI-LR location request for a UE with an IMS emergency call,

• receive and manage location requests from a GMLC for a 5GC-MT-LR and deferred 5GC-MT-LR for periodic, triggered and UE available location events,

• receive and manage location requests from a UE for a 5GC-MO-LR,

• receive and manage Event Exposure request for location information from an NEF,

• select an LMF,

• receive updated privacy requirements from a UE and transfer to a UDR via UDM,

• support cancelation of periodic or triggered location reporting for a target UE, • support change of a serving LMF for periodic or triggered location reporting for a target UE,

• when assistance data is broadcast by 5GS in ciphered form, the AMF receives ciphering keys from the LMF and forwards to suitably subscribed UEs using mobility management procedures.

[0042] The LMF shall determine the result of the positioning in geographical co-ordinates and/or in local co-ordinates. If requested and if available, the positioning result may also include the velocity of the UE. The coordinate type(s) is determined by LMF when receiving a location request, based on LCS Client type and supported GAD shapes. If the location request indicates regulatory LCS Client type the LMF shall determine a geographical location and optionally a location in local coordinates. For location request indicates a value added LCS Client type, the LMF may determine the UE location in local coordinates or geographical co-ordinates or both. Additional functions which may be performed by an LMF to support location services include the following.

• support a request for a single location received from a serving AMF for a target UE,

• support a request for periodic or triggered location received from a serving AMF for a target UE,

• determine position methods based on UE and PLMN capabilities, QoS, UE connectivity state per access type and LCS Client type,

• report UE location estimates directly to a GMLC for periodic or triggered location of a target UE,

• support cancelation of periodic or triggered location for a target UE,

• support the provision of broadcast assistance data to UEs via NG-RAN in ciphered or unciphered form and forward any ciphering keys to subscribed UEs via the AMF,

• support change of a serving LMF for periodic or triggered location reporting for a target UE.

[0043] In response to a LCS service request from an external client, a GMLC may transmit a Namf Location ProvidePositioninglnfo Request to the AMF. Upon receiving this Request, the AMF transmits a MLMF Location DetermineLocation Request. The LMF initiates a positioning measurement procedure in the wireless network and receives positioning measurements from, e.g., a UE or UEs served by nodes of the wireless network. The LMF then transmits a Nlmf Location DetermineLocation Response to the AMF. Upon receipt of this response, the AMF transmits a Namf Location ProvidePositioninglnfo Response to the GMLC, which then transmits a LCS service response to the external client.

[0044] The AMF invokes the Nlmf Location DetermineLocation service operation towards the LMF to request the current location of the UE. The service operation may include a LCS Correlation identifier, the serving cell identity of the Primary Cell in the Master RAN node and the Primary Cell in the Secondary RAN node when available based on Dual Connectivity scenarios, and the client type and may include an indication if UE supports LPP, the required QoS and Supported GAD shapes.

[0045] Particularly, in many cases an appropriate interface between AMF and LMF is required to optimize the positioning procedures, especially related to moving UEs and positioning sessions continuity, and for RRC INACTIVE positioning. Therefore, UE RRC information exchange between AMF and LMF can be beneficial and save UE power consumption, latency and signaling overhead.

[0046] Some problems remain:

• LMF is not aware of the UE RRC state, not have explicit knowledge. It has been also particularly agreed in RAN2#114 that the RAN should not expose the UE RRC state to LMF.

• For positioning in RRC INACTIVE there is no RRC state awareness in the LMF. On the UE side it is up to UE implementation (inter-layer interactions in UE), nevertheless there is no exposure of RRC state to the LPP layer.

• The basic question underlying the above is, how does one determine a UE position when the UE is in RRC INACTIVE or RRC IDLE state?

[0047] The impact of inactive RRC in positioning increases the signaling overhead and the latency. In particular, positioning measurements are conducted in an RRC connected state. In order to perform positioning measurements in RRC INACTIVE or RRC IDLE state, the UE needs to be brought back in the connected state by means of paging which requires involvement of the AMF. This results in overhead in terms of signaling and latency.

[0048] As such, special solutions for UE RRC inactive state when initiating a positioning process would be desirable, such that the positioning process is adapted to the RRC state, thereby inducing minimum signaling and latency overhead. However, such solutions need to consider that there isn’t such option in 3GPP that RAN provides information on the RRC state to the LMF.

[0049] In contrast to known conventional approaches to determining UE positioning that use excessive signaling to determine positioning when the UE is in RRC INACTIVE or RRC IDLE state, improved techniques for obtaining locations of UEs in a wireless network include, in response to a positioning request to determine a position of at least one UE in a wireless network, an LMF requests RRC state from an AMF and, if the RRC state is RRC INACTIVE or RRC IDLE, the LMF provides last-known location of the at least one UE to AMF for paging. Advantageously, the improved techniques may reduce latency and resource overhead (signaling overhead). This is particularly useful when the positioning estimation procedures needs to run for the UEs which are not in RRC CONNECTED state. Moreover, the LMF avoids initiating any positioning procedure if the UE is in RRC INACTIVE state. Furthermore, if the UE RRC status is not RRC_ CONNECTED, the LMF assists the AMF by providing the last known location to discover the UE.

[0050] FIG. 2 is a flow chart illustrating operation of a location management unit (e.g., a location management function (LMF)). The method of FIG. 2 is written from the perspective of a LMF configured to determine a location of a UE within a wireless network based on positioning measurements performed by the UE according to configuration instructions transmitted from the LMF. Operation 210 includes controlling receiving, by a location management unit associated with a wireless network from an access and mobility management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network. For example, location management unit may be a LMF configured to manage determining locations of UEs in wireless networks with which the LMF is associated. The access and mobility node may be an AMF that may have knowledge of the radio resource control status information of the UEs. As shown in FIG. 4, the LMF and AMF may communicate over a NL1 interface.

[0051] Operation 220 of FIG. 2 includes, in response to receiving the request to determine the location of the at least one user device, controlling transmitting, by the location management unit to the access and mobility management unit, a request to provide radio resource control status information of the at least one user device. Under conventional circumstances, because the LMF is not aware of the UEs’ RRC state, getting a location of the UEs with low latency and minimum signaling may be difficult. In contrast, the improved techniques provide signaling for the LMF to get RRC status information from the AMF, which among other services is configured to manage RRC status information for UEs in a wireless network.

[0052] Operation 230 of FIG. 2 includes controlling receiving, by the location management unit from the access and mobility management unit, the radio resource control status information of the at least one user device. The radio resource control status information (i.e., RRC status information) may take the form of an active (connected) mode or an inactive (unconnected) mode. The active mode may be the CM-Connected or RRC CONNECTED state; the inactive mode may be one of the RRC INACUVE or RRC-IDLE state.

[0053] Operation 240 of FIG. 2 includes controlling in response to the radio resource control status information indicating a user device of the at least one user device is in an inactive mode, control transmitting, to the access and mobility management unit, a previously estimated position of a user device of the at least one user device to cause the access and mobility management unit to trigger a radio resource control status change to an active mode for the user device in the vicinity of the previously estimated position to enable the location management unit to obtain the location of the user device within the wireless network. For example, the LMF may have received locations of a UE in the wireless network, only for that user device to have since gone to an inactive mode. In this case, the LMF may not simply send configuration information to the UE; the UE may need to have the AMF trigger the UE to change RRC status to an active mode, e.g., Connection Management (CM)-Connected or RRC CONNECTED. The LMF does this by sending the AMF the last-known location of the UE, e.g., the last location determination made by the LMF.

[0054] The LMF may be aware of the geo-coordinate information (latitude, longitude) of the UE, whereas AMF may be aware of UE status information which include UE location per tracking area and Connection Management state (CM-Connected and CM-Idle states). NG- RAN RRC_INACHVE may be only visible to AMF by request, while the UE may be in CM- Connected.

[0055] In summary, the improved techniques include enabling a communication framework between LMF and AMF for assisting updated UE RRC status information. Specifically, LMF requests from AMF the status information of the RRC state of the target UE and adjusts the positioning procedure based on that information received by the AMF. This is enabled via new signaling defined for the interface between AMF and LMF over NL1 interface. Once the LMF receives the location request to determine the UE position, the LMF may request the RRC state status information of the target UE from AMF. Specifically having the UE RRC status at LMF enables handling all requests including those involving UEs in the RRC INACTIVE state.

• If the UE status is active mode (Communication Management (CM)-Connected) the LMF can initiate the normal positioning procedure and estimate the UE position.

• If the UE status is not CM-Connected, (e g., RRC INACTIVE or RRC IDLE), then the LMF, instead of initiating the position estimation phase, it provides the last known location of UE to the AMF, such that AMF initiates paging procedure in order to discover the UE. Having such a procedure reduces latency and network signaling/ overhead.

• The AMF may automatically trigger an RRC status update, if there is any change in the RRC status of the UE/group of UEs. Having such information at the LMF enables handling of any location-related request in the network and assists the LMF in initiating positioning procedures

[0056] The method of FIG. 2 may further include, wherein initiating the second position measurement procedure includes, in response to the radio resource control status information indicating the user device of the at least one user device is in an active mode, controlling transmitting, to the user device, configuration information for performing a positioning measurement to determine the estimated position of the user device. That is, if the UE is in an active mode such as RRC CONNECTED or CM Connected, the LMF may instruct the UE to perform positioning measurements (with or without analogous measurements from a serving gNB) directly.

[0057] The method of FIG. 2 may also include, wherein controlling transmitting the request to provide radio resource control status information of the at least one user device includes providing, to a set of user devices served by the at least one network node, an indication of a membership in a group of user devices, the indication being based on at least one common property shared by the set of user devices; and generating the request to provide radio resource control status information of the group of user devices. The common property may include a location within the wireless network. For obtaining the RRC status information from AMF, LMF may request the RRC status information per UE or LMF may group the UEs based on e.g., location, activity level. The main idea is then to group UEs into groups when the LMF communicates with the AMF for obtaining RRC status information can save network resources and signaling, i.e., the LMF requests and obtains RRC status information for a group of UEs.

[0058] The method of FIG. 2, may also include, after receiving the radio resource control status information of the at least one user device, obtain an indication of whether a first timer associated with the location management unit is running; in response to an indication that the first timer is running, determine whether the at least one user device is in the active mode or the at least one user device is in the inactive mode; and in response to an indication that the first timer is not running, determine that the user equipment is in an unknown mode, wherein the unknown mode becomes an active mode or an inactive mode after the first timer is indicated to be running. In order to request the RRC status information, LMF and AMF may utilize two timers, the first timer at LMF and a second timer at AMF, denoted by T_LMP and T_AMF, respectively. In principle T_LMFand T_AMF not to be synchronized but in some of the implementation we may consider synchronized timer. Further details about these timers are discussed with regard to FIG. 5.

[0059] The method of FIG. 2 may further include restarting the first timer in response to receiving the radio resource control status information of the at least one user device. That is, T_LMF may be restarted when it had not been running when the LMF receives RRC status information from the AMF.

[0060] In the method of FIG. 2, the first timer may run asynchronously with a second timer associated with the access and mobility management unit. That is, T_LMF and T_AMF may be synchronized, or they may run independently of each other. For example, when T_AMF is not running, the AMF may not provide RRC status updates to the LMF. Accordingly, the LMF may not receive RRC status updates from the AMF even if its own timer is running.

[0061] The method of FIG. 2 may further include, in response to the second timer not running, control retransmitting, to the access and mobility management unit, the request to provide radio resource control status information of the at least one user device. For example, if the AMF had been sending RRC updates automatically while T_AMF was running and then stopped because T_AMF stopped running, the LMF may trigger T_AMF to restart by retransmitting the RRC status update request to the AMF. [0062] FIG. 3 is a flow chart illustrating operation of an access and mobility management unit (e.g., an access and mobility function (AMF)). For example, the method of FIG. 3 is written from the perspective of an AMF associated with a wireless network, that may participate in obtaining locations of UEs within the wireless network by providing RRC status of UEs within the wireless network to the LMF. Operation 310 includes controlling transmitting, by an access and mobility management unit associated with a wireless network to location management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network. For example, the request may originate as a LCS service request from an external client and is received by a gateway mobile location center (GMLC) accessed by the external client. The GMLC may then send a location request to the AMF, which then transmits a request to the LMF.

[0063] Operation 320 of FIG. 3 includes controlling receiving, by the access and mobility management unit from the location management unit, a request to provide radio resource control status information of the at least one user device. Under conventional circumstances, because the LMF is not aware of the UEs’ RRC state, getting a location of the UEs with low latency and minimum signaling may be difficult. In contrast, the improved techniques provide signaling for the LMF to get RRC status information from the AMF, which among other services is configured to manage RRC status information for UEs in a wireless network.

[0064] Operation 330 of FIG. 3 includes controlling transmitting, by the access and mobility management unit to the location management unit, the radio resource control status information of the at least one user device. The radio resource control status information (i.e., RRC status information) may take the form of an active (connected) mode or an inactive (unconnected) mode. The active mode may be the RRC CONNECTED state; the inactive mode may be one of the RRC INACTIVE or RRC-IDLE state.

[0065] Operation 340 of FIG. 3 includes controlling receiving, by the access and mobility management unit from the location management unit, positions of the at least one user device within the wireless network, the receiving of the positions being based on the radio resource control status information of the at least one user device. For example, the LMF may have received locations of a UE in the wireless network, only for that user device to have since gone to an inactive mode. In this case, the LMF may not simply send configuration information to the UE; the UE may need to have the AMF trigger the UE to change RRC status to an active mode, e.g., Connection Management (CM)-Connected or RRC CONNECTED. The LMF does this by sending the AMF the last-known location of the UE, e.g., the last location determination made by the LMF.

[0066] In the method of FIG. 3, the radio resource control status information of the at least one user device may indicate that the at least one user devices is in an inactive mode. In such a case, the method of FIG. 3 may further include controlling receiving, from the location management unit, a previously estimated position of the at least one user device; and control transmitting, to the at least one user device in the vicinity of the previously estimated position, a paging message to trigger a radio resource control status change to an active mode from the inactive mode.

[0067] For the method of FIG. 3, controlling transmitting the radio resource control status information of the at least one user device may include monitoring a first timer associated with the access and mobility management unit, the controlling transmitting of the radio resource control status information being based on whether the first timer is running. In order to request the RRC status information, LMF and AMF may utilize two timers, the second timer at LMF and a first timer at AMF, denoted by T_LMP and T_AMF, respectively. In principle T_LMFand T_AMF not to be synchronized but in some of the implementation we may consider synchronized timer. Further details about these timers are discussed with regard to FIG. 5.

[0068] For the method of FIG. 3, controlling transmitting the radio resource control status information of the at least one user device may include stopping transmitting the radio resource control status information in response to the first timer not running. For example, when T_AMF is not running, the AMF may not provide RRC status updates to the LMF. Accordingly, the LMF may not receive RRC status updates from the AMF even if its own timer is running. Along these lines, for the method of FIG. 3, controlling transmitting the radio resource control status information of the at least one user device may include continuing transmitting the radio resource control status information in response to the first timer running.

[0069] For the method of FIG. 3, controlling transmitting the radio resource control status information in response to the first timer running may include controlling transmitting the radio resource control status information in response to a radio resource control state of the at least one user devices being changed. For the method of FIG. 3, controlling transmitting the radio resource control status information in response to the radio resource control state of the at least one user devices being changed may include controlling transmitting the radio resource control status information only when the radio resource control state of the at least one user device changes from an active state to an RRC INACTIVE state.

[0070] For the method of FIG. 3, continuing transmitting the radio resource control status information in response to the first timer running may include controlling transmitting the radio resource control status information in response to receiving a request to provide the radio resource control status information to the location management unit. That is, the AMF may restart the T_AMP when the AMF receives a request for an RRC status from the LMF.

[0071] In the method of FIG. 3, the first timer may run asynchronously with a second timer associated with the location management unit. That is, T_LMP and T_AMP may be synchronized, or they may run independently of each other. For example, when T_AMP is not running, the AMF may not provide RRC status updates to the LMF. Accordingly, the LMF may not receive RRC status updates from the AMF even if its own timer is running.

[0072] For the method of FIG. 3, controlling transmitting the radio resource control status information of the at least one user device may include stopping transmitting the radio resource control status information in response to receiving, from the location management unit, the request to provide the radio resource control status information of the at least one user device while the first timer is not running.

[0073] The method of FIG. 3 may further include receiving an indication that a user device of the at least one user device has undergone a change in the radio resource control status information of the user device; and, in response to receiving the indication, control transmitting, to the location management unit, the request to determine the location of the at least one user device.

[0074] FIG. 5 is a signaling diagram illustrating an example setup 500 of a timer for RRC status communication, according to FIGs. 2-3. The system shown in FIG. 5 includes a an access and mobility node (AMF) and a location management unit (LMF) within a wireless network. As noted, in order to request the RRC status information, LMF and AMF may utilize two timers, one timer at LMF and one timer at AMF, denoted by T_LMP and T_AMP, respectively. In principle T_LMP and T_AMP may not be synchronized but in some of the implementation one may consider synchronized timers. • A timer T_LMF and T_AMF may be configured to supervise the activities related to the the RRC status information of one or more UEs at the LMF and the AMF, respectively. The value of the T_LMF, T_AMF may be UE specific or UE group specific. o The purpose of T_LMF is to ensure that the RRC status information does not get outdated, i.e., it corresponds to a (relatively) recent RRC status information; otherwise an update is requested. o The purpose of T_AMF is to ensure that AMF does not keep pushing RRC status updates to the LMF endlessly, i.e., it provides a reasonable time deadline after which providing further updates to LMF (without the LMF asking for it) would not be productive. o In case T_LMF and T_AMF are synchronized then it is assumed that the RRC status information validity time would be the same on both LMF and AMF. o In case of unsynchronized T_LMF and T_AMF, the validity of the two timers is decoupled. For example if the T_AMF=Q it will not push the latest RRC response to LMF until it receive explicit request from LMF which depend on the network configuration.

• The timer T_LMF is (re-)started when LMF receives RRC status request response from AMF.

• The timer T_AMF is (re-)started when AMF has provided the RRC status request response to LMF.

• While the timer T_LMF is running, the LMF can assume that the latest provided RRC status for the UE by the AMF is valid.

• While the timer T_AMF is running, the AMF provides the updated RRC status to the LMF, if the UE RRC status is different from what was previously provided for the UE. o Once provided by the AMF, the timer T_AMF is restarted at AMF. o Once received by the LMF, the timer T_LMF is restarted at LMF.

• When the timer T_LMF expires, the LMF cannot assume any UE RRC state, i.e. it may consider the status as “unknown.”

• When the timer T_AMF expires, the AMF is not required to provide any RRC state updates the UE associated with the timer. • As an example, the timer values can be configured in following manner: o Timer T_LMP = T_AMP = 1 sec => an update, for a relatively short period of time. AMF may update any change to UE RRC status but at the same time it increases LMF polling to AMF, i.e., frequent RRC status request. o Timer T_LMP = T_AMP = 10 sec => reduces LMF polling, but if there is an update on RRC status at AMF during T_AMP it may potentially increase AMF to LMF signaling.

[0075] According to the example setup 500 shown in FIG. 5, at 502 the LMF transmits a RRC status request to an AMF. Such a status request may be transmitted over a NL1 connection as shown in FIG. 4. The LMF may transmit the RRC status request in response to receiving a request from the AMF to obtain a location of a UE within a wireless network.

[0076] At 504, the AMF transmits a RRC status response to the LMF. The RRC status response may be an indication that the UE may be in an active mode or an inactive mode. The RRC status response may be an indication a UE is in an active mode or an inactive mode. The active mode may include any of RRC CONNECTED state or CM Connected state. The inactive mode may include any of RRC INACTIVE, RRC IDLE, or CM unconnected states. Sometime after the LMF receives the RRC status response from the AMF, the LMF may start the timer T_LMP.

[0077] At 506, the AMF starts the timer T_AMP. As a result of T_AMP running, when the AMF receives an indication of an RRC status change for a UE at 508, at 510 the AMF updates the RRC status response at 510. The AMF may also transmit an RRC status response to the LMF according to a schedule, e.g., at a set frequency.

[0078] Between 510 and 512, the timer T_AMP expires. That is, the timer T_AMP is no longer running, and the AMF will not transmit RRC status updates to the LMF while the timer T_AMP is not running. Accordingly, at 512, the AMF does not send a RRC status update to the LMF when the AMF receives an indication of a RRC status change for a UE. Moreover, at 514, the AMF takes no action with regard to RRC status updates while the time is not running. If the timers T_LMP and T_AMP are synchronized, then the timer T_LMP stops when the timer T_AMP stops. If, in contrast, the timers T_LMP and T_AMP run asynchronously, then the timer T_LMP may stop running at some point while there are no RRC status updates being received by the LMF. The timer T_LMP may continue to run whether the T_AMF is running or not. 1

[0079] At 516, the LMF sends a RRC status request to the AMF and, as a result, at 518 the AMF restarts the timer T_AMP and sends a RRC status response to the LMF at 520. As shown in FIG. 5, the LMF restarts the timer T_LMP at 522 upon receiving the RRC status response.

[0080] FIG. 6 is a flow chart illustrating operation 600 of a LMF with regard to timerbased RRC status communication. At 610 the AMF sends a location request to the LMF, e.g., as in the method of FIG. 3, at 310.

[0081] At 620, the LMF attempts to acquire an RRC status from AMF. To this effect, the LMF transmits a RRC status request 621 to the AMF. After a period of waiting at 602, the AMF may respond with a RRC status response 622. The AMF may independently push the latest RRC status of the UE if an RRC status update arrives at the AMF from an NG-RAN within the timer T_AMP.

[0082] Upon reception of the RRC status from the AMF, at 623 the LMF may check whether the timer T_LMP is running. If the timer T_LMP is not running then at 624 the LMF starts the timer T_LMP. If the timer T_LMP is running then at 650, then the LMF may perform a RRC status check 650.

[0083] Upon reception of RRC status from AMF, LMF checks whether the timer T_LMP is running at 630. If the timer T_LMP is not running, then at 640 the RRC status is “unknown.” When the RRC status is “unknown” LMF goes to the RRC status “unknown” state. In order to obtain a RRC status, the LMF may retransmit the RRC status request 621. If the timer T_LMP is running, then the RRC status is “known.” When the RRC status is “known” LMF goes to RRC status check state at 650, from where the UE or group of UEs are identified being either as connected or not connected.

[0084] If the RRC status is “Not RRC Connected” (e.g., inactive mode) 660, then the LMF initiates a request 661 to discover the UE/set of UEs by providing the last known location.

Once the UEs are discovered, the AMF provides RRC status and after a period of waiting at 602, the AMF may respond with a RRC status response 622. The AMF may independently push the latest RRC status of the UE if an RRC status update arrives at the AMF from an NG- RAN within the timer T_AMP.

[0085] If the RRC status in step 5 is “RRC Connected” (e.g., active mode), the LMF initiates the positioning procedure for this UE or group of UEs at 670. [0086] FIG. 7 is a flow chart illustrating operation 700 of an AMF with regard to timerbased RRC status communication. At 710, the AMF is in a waiting state to process incoming requests from different entities of a wireless network. The AMF may obtain an RRC status request 721 from the LMF. The AMF may obtain NG-RAN RRC status change information 711.

[0087] If the AMF obtains the RRC status request 721 from the LMF, the AMF will enter to get RRC status state in order to discover the UE/set of UEs RRC status information. Once the AMF obtains the RRC status information for the UE/set of UEs, the AMF sends a RRC status response 722 to the LMF. After sending the RRC status response 722 to the LMF, the AMF at 730 starts the timer T_AMF.

[0088] If there is incoming RRC status change information from the NG-RAN, at 740 the AMF checks the timer T_AMF. If the T_AMF is not running then the AMF does not provide any update to LMF and goes to waiting state 710. If, in contrast, the T_AMF is running then the AMF may send an RRC status response at 750 to the LMF.

[0089] FIG. 8 is a signaling diagram illustrating a positioning scheme 800 performed according to the methods described in FIGs. 2-3. Note that the signalling between the LMF and AMF is performed via a NL1 interface as shown in FIG. 4. At 801, an external client sends a LCS request to a GMLC. At 802, the GMLC sends a UECM get request to a UDM. The GMLC also sends a location information request to the AMF at 803; this results in a network- triggered service request at 804. At 805, the AMF transmits a request to determine a location of a UE in a wireless network to the LMF.

[0090] At 810, a setup phase begins. Before sending the UE RRC status, LMF sets the IE RRC status to “unknown.” The LMF sends the RRC status request message to the AMF related to one particular UE or group of UEs. The LMF may request the RRC status information from the AMF in any of the following ways.

• The LMF may request from the AMF to autonomously update the UE status such that if the UE status changed at AMF, the AMF automatically sends the UE status update to LMF.

• The LMF may request the AMF to update the UE status on request basis.

• The LMF may request the AMF to share the UE status only if the UE status change from RRC CONNECTED to RRC INACTIVE or vice-versa. • LMF may request the AMF to share the UE status based on the timer.

[0091] In the case of the RRC status information request being for a group of UEs, at 811 the LMF, in response to the determine location request 805, transmits a group RRC status information request to the AMF. At 812, the AMF sends a group RRC status information response that provides RRC statuses for the group of UEs.

[0092] In the case of the RRC status information request being per UE, at 813 the LMF, in response to the determine location request 805, transmits a UE RRC status information request to the AMF. At 814, the AMF sends a UE RRC status information response that provides a RRC status for the UE.

[0093] At 820, a check RRC status phase begins. The LMF determines the RRC status of the UE/group of UEs and, based on the RRC status the LMF may do one of the following operations.

• If the status of the UE/group of the UEs is RRC INACTIVE, the LMF sends request to AMF to discover the UE/group of the UEs in the serving/neighboring/tracking area level. Specifically, LMF can assist AMF by providing last known location of the UE/group of the UEs to AMF which can utilized by AMF to discover the UE/group of UEs. Accordingly, at 821, the LMF sends last-known location information of the UE/group of UEs to the AMF. The AMF sends the LMF a discovery response at 822. The discovery response may include an indication of a RRC status change from the UR/group of UEs.

• If the status is RRC CONNECTED, the LMF at 823 initiates the UE position estimation phase.

[0094] At 830, once the LMF is informed that the UE/group of UEs in question are in an active mode (e.g., RRC CONNECTED), the LMF may obtain location estimates from the UE/group of UEs at 830. At 831, the AMF sends the location estimates to the GMLC, and at 832 the GMLC sends a LCS service response to the external client.

[0095] Some further examples will be provided.

[0096] Example 1. A method may include:

[0097] controlling receiving (e.g., 210, FIG. 2), by a location management unit (e.g., LMF 430, FIG. 4) associated with a wireless network from an access and mobility management unit (e.g., AMF 440, FIG. 4) associated with the wireless network, a request (e.g., location request 610, FIG. 6) to determine a location of at least one user device (e.g., UE 410, FIG. 4) served by at least one network node (e.g., gNB 424, FIG. 4) within the wireless network;

[0098] in response to receiving the request to determine the location of the at least one user device, controlling transmitting (220, FIG. 2), by the location management unit to the access and mobility management unit, a request (e.g., query 620, FIG. 6) to provide radio resource control status information (RRC status information 750, FIG. 7) of the at least one user device;

[0099] controlling receiving (e.g., 230, FIG. 2), by the location management unit from the access and mobility management unit, the radio resource control status information of the at least one user device; and

[0100] in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control transmitting (240, FIG. 2), to the access and mobility management unit, a previously estimated position (last known location information 821, FIG. 8) of the one or more user devices of the at least one user device to cause the access and mobility management unit to trigger a radio resource control status change (UE discovery response 822, FIG. 8) to an active mode for at least one user device in the vicinity of the previously estimated position to enable the location management unit to determine the requested location.

[0101] Example 2. The method of example 1, wherein initiating the second position measurement procedure includes, in response to the radio resource control status information indicating the user device of the at least one user device is in an active mode, control transmitting, to the user device, configuration information (UE positioning 823, FIG. 8) for performing a positioning measurement to determine the estimated position of the user device.

[0102] Example 3. The method of any of examples 1-2, wherein controlling transmitting the request to provide radio resource control status information of the at least one user device includes providing, to a set of user devices served by the at least one network node, an indication (e.g., setup phase 810, FIG. 8) of a membership in a group of user devices, the indication being based on at least one common property shared by the set of user devices; and generating the request to provide radio resource control status information of the group of user devices (e.g., group RRC status information request 811, FIG. 8).

[0103] Example 4. The method of example 3, wherein the common property includes a location within the wireless network. [0104] Example 5. The method of any of examples 1-4, further comprising: after receiving the radio resource control status information of the at least one user device, obtaining an indication of whether a first timer associated with the location management unit is running (e.g., 623, FIG. 6); in response to an indication that the first timer is running, determining whether the at least one user device is in the active mode or the at least one user device is in the inactive mode (e.g., RRC status check 650, FIG. 6); and, in response to an indication that the first timer is not running, determine that the user equipment is in an unknown mode (e.g., 640, FIG. 6), wherein the unknown mode becomes an active mode or an inactive mode after the first timer is indicated to be running.

[0105] Example 6. The method of example 5, further comprising restarting the first timer in response to receiving the radio resource control status information of the at least one user device (e.g., 520, FIG. 5).

[0106] Example 7. The method of any of examples 5 or 6, wherein the first timer runs asynchronously with a second timer associated with the access and mobility management unit.

[0107] Example 8. The method of example 7, further comprising, in response to the second timer not running (740, FIG. 7), control retransmitting, to the access and mobility management unit, the request to provide radio resource control status information of the at least one user device.

[0108] Example 9. An apparatus comprising means (e.g., transceiver 902A, processor 904 and/or memory 906, FIG. 9) for performing the method of any of examples 1-8.

[0109] Example 10. An apparatus comprising: at least one processor (e.g., processor 904, FIG. 9); and at least one memory (e.g., memory 906, FIG. 9) including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform the method of any of examples 1-8.

[0110] Example 11. An apparatus comprising: at least one processor (e.g., processor 904, FIG. 9); and at least one memory (e.g., memory 906, FIG. 9) including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: control receiving, by a location management unit associated with a wireless network from an access and mobility management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network; in response to receiving the request to determine the location of the at least one user device, control transmitting, by the location management unit to the access and mobility management unit, a request to provide radio resource control status information of the at least one user device; control receiving, by the location management unit from the access and mobility management unit, the radio resource control status information of the at least one user device; and, in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control transmitting, to the access and mobility management unit, a previously estimated position of the one or more user devices of the at least one user device to cause the access and mobility management unit to trigger a radio resource control status change to an active mode for at least one user device in the vicinity of the previously estimated position to enable the location management unit to determine the requested location. (See examples and further details described above with reference to Example 1).

[0111] Example 12. A method comprising: controlling transmitting (310, FIG. 3), by an access and mobility management unit associated with a wireless network to location management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network; controlling receiving (320, FIG. 3), by the access and mobility management unit from the location management unit, a request to provide radio resource control status information of the at least one user device; controlling transmitting (330, FIG. 3), by the access and mobility management unit to the location management unit, the radio resource control status information of the at least one user device; in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control receiving, from the location management unit, a previously estimated position of the one or more user devices of the at least one user device; and control transmitting, to the wireless network, a request to a radio resource control status change to an active mode for at least one user device in the vicinity of the previously estimated position for determining the requested location .

[0112] Example 13. The method of example 12, wherein the radio resource control status information of the at least one user device indicates that the at least one user devices is in an inactive mode, and wherein the method further includes controlling receiving, from the location management unit, a previously estimated position of the at least one user device; and control transmitting, to the at least one user device in the vicinity of the previously estimated position, a paging message to trigger a radio resource control status change to an active mode from the inactive mode.

[0113] Example 14. The method of any of examples 10 or 11, wherein controlling transmitting the radio resource control status information of the at least one user device includes monitoring a first timer (e.g., 740, FIG. 7) associated with the access and mobility management unit, the controlling transmitting of the radio resource control status information being based on whether the first timer is running.

[0114] Example 15. The method of any of examples 10-12, wherein controlling transmitting the radio resource control status information of the at least one user device includes stopping transmitting the radio resource control status information (e.g., 514, FIG. 5) in response to the first timer not running.

[0115] Example 16. The method of any of examples 10-13, wherein controlling transmitting the radio resource control status information of the at least one user device includes continuing transmitting the radio resource control status information (e.g., 510, FIG. 5) in response to the first timer running.

[0116] Example 17. The method of example 16, wherein continuing transmitting the radio resource control status information in response to the first timer running includes controlling transmitting the radio resource control status information in response to a radio resource control state of the at least one user devices being changed (e.g., 750, FIG. 7).

[0117] Example 18. The method of example 17, wherein controlling transmitting the radio resource control status information in response to the radio resource control state of the at least one user device being changed includes controlling transmitting the radio resource control status information only when the radio resource control state of the at least one user device changes from an active state to a RRC INACTIVE state.

[0118] Example 19. The method of any of examples 17 or 18, wherein continuing transmitting the radio resource control status information in response to the first timer running includes controlling transmitting the radio resource control status information in response to receiving a request to provide the radio resource control status information to the location management unit.

[0119] Example 20. The method of any of examples 18-20, wherein the first timer runs asynchronously with a second timer associated with the location management unit.

[0120] Example 21. The method of any of examples 12-20, wherein controlling transmitting the radio resource control status information of the at least one user device includes stopping transmitting the radio resource control status information in response to receiving, from the location management unit, the request to provide the radio resource control status information of the at least one user device while the first timer is not running.

[0121] Example 22. The method of any of examples 12-21, further comprising receiving an indication that the at least one user device has undergone a change in the radio resource control status information of the user device; and, in response to receiving the indication, control transmitting, to the location management unit, the request to determine the location of the at least one user device.

[0122] Example 23. An apparatus comprising means (e.g., processor 904, transceiver 902A and/or memory 906, FIG. 9) for performing the method of any of examples 12-22.

[0123] Example 24. An apparatus comprising: at least one processor (e.g., processor 904, FIG. 9); and at least one memory (e.g., memory 906, FIG. 9) including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform the method of any of claims 12-22.

[0124] Example 25. An apparatus comprising: at least one processor (e.g., processor 904, FIG. 9); and at least one memory (e.g., memory 906, FIG. 9) including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: control receiving, by the access and mobility management unit from the location management unit, a request to provide radio resource control status information of the at least one user device; control transmitting, by the access and mobility management unit to the location management unit, the radio resource control status information of the at least one user device; in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control receiving, from the location management unit, a previously estimated position of the one or more user devices of the at least one user device; and control transmitting, to the wireless network, a request to a radio resource control status change to an active mode for at least one user device in the vicinity of the previously estimated position for determining the requested location. [0125] List of abbreviations:

DL Downlink gNB NR base station

AMF Access and Mobility Management Function

CSLRS Channel State Information Reference Signals LMF Location Management Function

NR New (5G) Radio

PRS Positioning Reference Signal RRC Radio Resource Control

SSB Synchronization Signal Block

UE User Equipment

UL Uplink

[0126] FIG. 9 is a block diagram of a wireless station (e.g., user node, network node, or other node) 900 according to an example embodiment. The wireless station 900 may include, for example, one or more (e.g., two as shown in FIG. 9) RF (radio frequency) or wireless transceivers 902A, 902B, where each wireless transceiver includes a transmitter to transmit signals and a receiver to receive signals. The wireless station also includes a processor or control unit/entity (controller) 904 to execute instructions or software and control transmission and receptions of signals, and a memory 906 to store data and/or instructions.

[0127] Processor 904 may also make decisions or determinations, generate frames, packets or messages for transmission, decode received frames or messages for further processing, and other tasks or functions described herein. Processor 904, which may be a baseband processor, for example, may generate messages, packets, frames or other signals for transmission via wireless transceiver 902 (902A or 902B). Processor 904 may control transmission of signals or messages over a wireless network, and may control the reception of signals or messages, etc., via a wireless network (e.g., after being down-converted by wireless transceiver 902, for example). Processor 904 may be programmable and capable of executing software or other instructions stored in memory or on other computer media to perform the various tasks and functions described above, such as one or more of the tasks or methods described above. Processor 904 may be (or may include), for example, hardware, programmable logic, a programmable processor that executes software or firmware, and/or any combination of these. Using other terminology, processor 904 and transceiver 902 together may be considered as a wireless transmitter/receiver system, for example.

[0128] In addition, referring to FIG. 9, a controller (or processor) 908 may execute software and instructions, and may provide overall control for the station 900, and may provide control for other systems not shown in FIG. 9, such as controlling input/output devices (e.g., display, keypad), and/or may execute software for one or more applications that may be provided on wireless station 900, such as, for example, an email program, audio/video applications, a word processor, a Voice over IP application, or other application or software.

[0129] In addition, a storage medium may be provided that includes stored instructions, which when executed by a controller or processor may result in the processor 904, or other controller or processor, performing one or more of the functions or tasks described above.

[0130] According to another example embodiment, RF or wireless transceiver(s) 902A/902B may receive signals or data and/or transmit or send signals or data. Processor 904 (and possibly transceivers 902A/902B) may control the RF or wireless transceiver 902A or 902B to receive, send, broadcast or transmit signals or data.

[0131] The embodiments are not, however, restricted to the system that is given as an example, but a person skilled in the art may apply the solution to other communication systems. Another example of a suitable communications system is the 5G concept. It is assumed that network architecture in 5G may be similar to that of LTE-advanced. 5G is likely to use multiple input - multiple output (MIMO) antennas, many more base stations or nodes than LTE (a so- called small cell concept), including macro sites operating in co-operation with smaller stations and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates.

[0132] 6G networks are expected to adopt flexible decentralized architecture and ubiquitous computing, with local spectrum licensing, spectrum sharing, infrastructure sharing, and intelligent automated management underpinned by mobile edge computing, artificial intelligence, short-packet communication and blockchain technologies. Key features of 6G will include intelligent connected management and control functions, programmability, integrated sensing and communication, reduction of energy footprint, trustworthy infrastructure, scalability and affordability. In addition 6G is also targeting new use cases covering the integration of localization and sensing capabilities into system definition to unifying user experience across physical and digital worlds.

[0133] AMF and LMF are core network functions that may be virtualized and be cloudnative. The Core Access and Mobility Management Function (AMF) is part of the 3GPP 5G Architecture. Its primary tasks include: Registration Management, Connection Management, Reachability Management, Mobility Management and various function relating to security and access management and authorization. AMF transmits a location services request to Location Management Function (LMF). The LMF processes the location services request which may include transferring assistance data to the target UE to assist with UE-based and/or UE-assisted positioning and/or may include positioning of the target UE.

[0134] It should be appreciated that future networks will most probably utilise network functions virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into “building blocks” or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running computer program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications this may mean node operations may be carried out, at least partly, in a server, host or node may be operationally coupled to a remote radio head. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of labour between core network operations and base station operations may differ from that of the LTE or even be non-existent.

[0135] Embodiments of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Embodiments may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine readable storage device or in a propagated signal, for execution by, or to control the operation of, a data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. Embodiments may also be provided on a computer readable medium or computer readable storage medium, which may be a non-transitory medium. Embodiments of the various techniques may also include embodiments provided via transitory signals or media, and/or programs and/or software embodiments that are downloadable via the Internet or other network(s), either wired networks and/or wireless networks. In addition, embodiments may be provided via machine type communications (MTC), and also via an Internet of Things (IOT).

[0136] The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a number of computers.

[0137] Furthermore, embodiments of the various techniques described herein may use a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the embodiment and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers, . . .) embedded in physical objects at different locations. Mobile cyber physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals. The rise in popularity of smartphones has increased interest in the area of mobile cyber-physical systems. Therefore, various embodiments of techniques described herein may be provided via one or more of these technologies.

[0138] A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit or part of it suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[0139] Method steps may be performed by one or more programmable processors executing a computer program or computer program portions to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0140] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer, chip or chipset. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magnetooptical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magnetooptical disks; and CDROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0141] To provide for interaction with a user, embodiments may be implemented on a computer having a display device, e.g., a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to the user and a user interface, such as a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0142] Embodiments may be implemented in a computing system that includes a backend component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a frontend component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an embodiment, or any combination of such backend, middleware, or frontend components. Components may be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN) and a wide area network (WAN), e.g., the Internet.

[0143] While certain features of the described embodiments have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the various embodiments.

Claims

WHAT IS CLAIMED IS: An apparatus, comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to cause the apparatus at least to: control receiving, by a location management unit associated with a wireless network from an access and mobility management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network; in response to receiving the request to determine the location of the at least one user device, control transmitting, by the location management unit to the access and mobility management unit, a request to provide radio resource control status information of the at least one user device; control receiving, by the location management unit from the access and mobility management unit, the radio resource control status information of the at least one user device; and in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control transmitting, to the access and mobility management unit, a previously estimated position of the one or more user devices of the at least one user device to cause the access and mobility management unit to trigger a radio resource control status change to an active mode for at least one user device in the vicinity of the previously estimated position to enable the location management unit to determine the requested location. The apparatus as in claim 1, wherein the at least one memory and the computer program code are further configured to cause the apparatus at least to: in response to the radio resource control status information indicating the user device of the at least one user device is in an active mode, control transmitting, to the user device, configuration information for performing a positioning measurement to determine the estimated position of the user device. The apparatus as in any of claims 1 or 2, wherein the at least one memory and the computer program code configured to cause the apparatus at least to control transmitting the request to provide radio resource control status information of the at least one user device are further configured to cause the apparatus to: provide, to a set of user devices served by the at least one network node, an indication of a membership in a group of user devices, the indication being based on at least one common property shared by the set of user devices; and generate the request to provide radio resource control status information of the group of user devices. The apparatus as in claim 3, wherein the common property includes a location within the wireless network. The apparatus as in any of claims 1-4, wherein the at least one memory and the computer program code are further configured to cause the apparatus to: after receiving the radio resource control status information of the at least one user device, obtain an indication of whether a first timer associated with the location management unit is running; in response to an indication that the first timer is running, determine whether the at least one user device is in the active mode or the at least one user device is in the inactive mode; and in response to an indication that the first timer is not running, determine that the user equipment is in an unknown mode, wherein the unknown mode becomes an active mode or an inactive mode after the first timer is indicated to be running. The apparatus as in claim 5, wherein the at least one memory and the computer program code are further configured to cause the apparatus to: restart the first timer in response to receiving the radio resource control status information of the at least one user device. The apparatus as in any of claims 5 or 6, wherein the first timer runs asynchronously with a second timer associated with the access and mobility management unit. The apparatus as in claim 7, wherein the at least one memory and the computer program code are further configured to cause the apparatus to: in response to the second timer not running, control retransmitting, to the access and mobility management unit, the request to provide radio resource control status information of the at least one user device. A method, comprising: controlling receiving, by a location management unit associated with a wireless network from an access and mobility management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network; in response to receiving the request to determine the location of the at least one user device, controlling transmitting, by the location management unit to the access and mobility management unit, a request to provide radio resource control status information of the at least one user device; controlling receiving, by the location management unit from the access and mobility management unit, the radio resource control status information of the at least one user device; and in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control transmitting, to the access and mobility management unit, a previously estimated position of the one or more user devices of the at least one user device to cause the access and mobility management unit to trigger a radio resource control status change to an active mode for at least one user device in the vicinity of the previously estimated position to enable the location management unit to determine the requested location. 10. The method as in claim 9, further comprising: in response to the radio resource control status information indicating the user device of the at least one user device is in an active mode, controlling transmitting, to the user device, configuration information for performing a positioning measurement to determine the estimated position of the user device.

11. The method as in any of claims 9 or 10, wherein controlling transmitting the request to provide radio resource control status information of the at least one user device includes: providing, to a set of user devices served by the at least one network node, an indication of a membership in a group of user devices, the indication being based on at least one common property shared by the set of user devices; and generating the request to provide radio resource control status information of the group of user devices.

12. The method as in claim 11, wherein the common property includes a location within the wireless network.

13. The method as in any of claims 9-12, further comprising: after receiving the radio resource control status information of the at least one user device, obtaining an indication of whether a first timer associated with the location management unit is running; in response to an indication that the first timer is running, determining whether the at least one user device is in the active mode or the at least one user device is in the inactive mode; and in response to an indication that the first timer is not running, determining that the user equipment is in an unknown mode, wherein the unknown mode becomes an active mode or an inactive mode after the first timer is indicated to be running.

14. The method as in claim 13, wherein the at least one memory and the computer program code are further configured to cause the apparatus to: restart the first timer in response to receiving the radio resource control status information of the at least one user device. The method as in any of claims 13 or 14, wherein the first timer runs asynchronously with a second timer associated with the access and mobility management unit. The method as in claim 15, wherein the at least one memory and the computer program code are further configured to cause the apparatus to: in response to the second timer not running, control retransmitting, to the access and mobility management unit, the request to provide radio resource control status information of the at least one user device. An apparatus comprising means for performing the method of any of claims 9-16. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform the method of any of claims 9- 16. An apparatus, comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to cause the apparatus at least to: control transmitting, by an access and mobility management unit associated with a wireless network to location management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network; control receiving, by the access and mobility management unit from the location management unit, a request to provide radio resource control status information of the at least one user device; control transmitting, by the access and mobility management unit to the location management unit, the radio resource control status information of the at least one user device; in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control receiving, from the location management unit, a previously estimated position of the one or more user devices of the at least one user device; and control transmitting, to the wireless network, a request to a radio resource control status change to an active mode for at least one user device in the vicinity of the previously estimated position for determining the requested location.

20. The apparatus as in claim 19, wherein the radio resource control status information of the at least one user device indicates that the at least one user device is in an inactive mode, and wherein the at least one memory and the computer program code are further configured to cause the apparatus to: control receiving, from the location management unit, a previously estimated position of the at least one user device; and control transmitting, to the at least one user device in the vicinity of the previously estimated position, a paging message to trigger a radio resource control status change to an active mode from the inactive mode.

21. The apparatus as in any of claims 19 or 20, wherein the at least one memory and the computer program code configured to cause the apparatus at least to control transmitting the radio resource control status information of the at least one user device are further configured to cause the apparatus to: monitor a first timer associated with the access and mobility management unit, the controlling transmitting of the radio resource control status information being based on whether the first timer is running.

22. The apparatus as in any of claims 19-21, wherein the at least one memory and the computer program code configured to cause the apparatus at least to control transmitting the radio resource control status information of the at least one user device are further configured to cause the apparatus to: stop transmitting the radio resource control status information in response to the first timer not running.

23. The apparatus as in any of claims 19-22, wherein the at least one memory and the computer program code configured to cause the apparatus at least to control transmitting the radio resource control status information of the at least one user device are further configured to cause the apparatus to: continue transmitting the radio resource control status information in response to the first timer running.

24. The apparatus as in claim 23, wherein the at least one memory and the computer program code configured to cause the apparatus at least to continue transmitting the radio resource control status information in response to the first timer running are further configured to cause the apparatus to: control transmitting the radio resource control status information in response to a radio resource control state of the at least one user devices being changed.

25. The apparatus as in claim 24, wherein the at least one memory and the computer program code configured to cause the apparatus at least to control transmitting the radio resource control status information in response to the radio resource control state of the at least one user device of the at least one user devices being changed are further configured to cause the apparatus to: control transmitting the radio resource control status information only when the radio resource control state of the at least one user device changes from an active state to a RRC INACUVE state.

26. The apparatus as in any of claims 24 or 25, wherein the at least one memory and the computer program code configured to cause the apparatus at least to continue transmitting the radio resource control status information in response to the first timer running are further configured to cause the apparatus to: control transmitting the radio resource control status information in response to receiving a request to provide the radio resource control status information to the location management unit.

27. The apparatus as in any of claims 24-26, wherein the first timer runs asynchronously with a second timer associated with the location management unit.

28. The apparatus as in any of claims 19-27, wherein the at least one memory and the computer program code configured to cause the apparatus at least to control transmitting the radio resource control status information of the at least one user device are further configured to cause the apparatus to: stop transmitting the radio resource control status information in response to receiving, from the location management unit, the request to provide the radio resource control status information of the at least one user device while the first timer is not running.

29. The apparatus as in any of claims 19-28, wherein the at least one memory and the computer program code configured to cause the apparatus at least to: receive an indication that the at least one user device has undergone a change in the radio resource control status information of the user device; and in response to receiving the indication, control transmitting, to the location management unit, the request to determine the location of the at least one user device.

30. A method, comprising: controlling transmitting, by an access and mobility management unit associated with a wireless network to location management unit associated with the wireless network, a request to determine a location of at least one user device served by at least one network node within the wireless network; controlling receiving, by the access and mobility management unit from the location management unit, a request to provide radio resource control status information of the at least one user device; controlling transmitting, by the access and mobility management unit to the location management unit, the radio resource control status information of the at least one user device; in response to the radio resource control status information indicating one or more user devices of the at least one user device is in an inactive mode, control receiving, from the location management unit, a previously estimated position of the one or more user devices of the at least one user device; and control transmitting, to the wireless network, a request to a radio resource control status change to an active mode for at least one user device in the vicinity of the previously estimated position for determining the requested location.

31. The method as in claim 30, wherein the radio resource control status information of the at least one user device indicates that the at least one user device is in an inactive mode, and wherein the method further comprises: controlling receiving, from the location management unit, a previously estimated position of the at least one user device; and controlling transmitting, to the at least one user device in the vicinity of the previously estimated position, a paging message to trigger a radio resource control status change to an active mode from the inactive mode.

32. The method as in any of claims 30 or 31, wherein controlling transmitting the radio resource control status information of the at least one user device includes: monitoring a first timer associated with the access and mobility management unit, the controlling transmitting of the radio resource control status information being based on whether the first timer is running.

33. The method as in any of claims 30-32, wherein controlling transmitting the radio resource control status information of the at least one user device includes: stopping transmitting the radio resource control status information in response to the first timer not running.

34. The method as in any of claims 30-33, wherein controlling transmitting the radio resource control status information of the at least one user device includes: continuing transmitting the radio resource control status information in response to the first timer running.

35. The method as in claim 34, wherein continuing transmitting the radio resource control status information in response to the first timer running includes: controlling transmitting the radio resource control status information in response to a radio resource control state of the at least one user devices being changed.

36. The method as in claim 35, wherein controlling transmitting the radio resource control status information in response to the radio resource control state of the at least one user device of the at least one user devices being changed includes: controlling transmitting the radio resource control status information only when the radio resource control state of the at least one user device changes from an active state to a RRC INACTIVE state.

37. The method as in any of claims 35 or 36, wherein continuing transmitting the radio resource control status information in response to the first timer running includes: controlling transmitting the radio resource control status information in response to receiving a request to provide the radio resource control status information to the location management unit. 38. The method as in any of claims 35-37, wherein the first timer runs asynchronously with a second timer associated with the location management unit.

39. The method as in any of claims 30-38, wherein controlling transmitting the radio resource control status information of the at least one user device includes: stopping transmitting the radio resource control status information in response to receiving, from the location management unit, the request to provide the radio resource control status information of the at least one user device while the first timer is not running.

40. The method as in any of claims 30-39, further comprising: receiving an indication that the at least one user device has undergone a change in the radio resource control status information of the user device; and in response to receiving the indication, controlling transmitting, to the location management unit, the request to determine the location of the at least one user device.

41. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform the method of any of claims 30-40.

42. An apparatus comprising means for performing a method according to any of preceding claims 30-40. .