WO2022148656A1

WO2022148656A1 - Positioning in cellular communication networks

Info

Publication number: WO2022148656A1
Application number: PCT/EP2021/087294
Authority: WO
Inventors: Oana-Elena Barbu; Benny Vejlgaard; Johannes Harrebek; Simon Svendsen; Amir Mehdi AHMADIAN TEHRANI
Original assignee: Nokia Technologies Oy
Priority date: 2021-01-11
Filing date: 2021-12-22
Publication date: 2022-07-14
Also published as: EP4275414A1; CN116746276A

Abstract

According to an example aspect of the present invention, there is provided an apparatus, comprising means for transmitting an inactive state measurement request to a user equipment, to request the user equipment to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report upon switching from the inactive state to a connected state, means for receiving the inactive state measurement report from the user equipment, wherein the inactive state measurement report comprises information about the at least one positioning measurement performed by the user equipment when the user equipment was in the inactive state, means for generating, based at least on said information about the at least one positioning measurement performed by the user equipment, a mobility profile of the user equipment and means for transmitting the mobility profile of the user equipment to a base station serving the user equipment.

Description

POSITIONING IN CELLULAR COMMUNICATION NETWORKS

FIELD

[0001] Various example embodiments relate in general to cellular communication networks and more specifically, to positioning in such networks.

BACKGROUND

[0002] Performance of cellular communication networks may be improved by exploiting known, or predicted, locations of User Equipments, UEs. By tracking positions of UEs, a network can optimize its resource usage for example. In addition, many applications require, and/or benefit from, accurate tracking of positions of the UEs, especially the high speed UEs.

[0003] Tracking of positions of UEs is thus important in cellular communication networks, such as in networks operating according to Long Term Evolution, LTE, and/or 5G radio access technology. 5G radio access technology may also be referred to as New Radio, NR, access technology. Since its inception, LTE has been widely deployed and 3rd Generation Partnership Project, 3GPP, still develops LTE. Similarly, 3GPP also develops standards for 5G/NR. Topics of the 3GPP discussions include network efficiency and positioning. According to the discussions there is a need to provide improved methods, apparatuses and computer programs for positioning. Such improvements may be used in other cellular communication networks in the future as well.

SUMMARY

[0004] According to some aspects, there is provided the subject-matter of the independent claims. Some example embodiments are defined in the dependent claims.

[0005] The scope of protection sought for various example embodiments of the invention is set out by the independent claims. The example embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various example embodiments of the invention.

[0006] According to a first aspect of the present invention, there is provided an apparatus, comprising means for means for transmitting an inactive state measurement request to a user equipment, to request the user equipment to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report upon switching from the inactive state to a connected state, means for receiving the inactive state measurement report from the user equipment, wherein the inactive state measurement report comprises information about the at least one positioning measurement performed by the user equipment when the user equipment was in the inactive state, means for generating, based at least on said information about the at least one positioning measurement performed by the user equipment, a mobility profile of the user equipment and means for transmitting the mobility profile of the user equipment to a base station serving the user equipment. The apparatus of the first aspect may comprise a location management entity or means for controlling the location management entity.

[0007] According to a second aspect of the present invention, there is provided an apparatus, comprising means for means for receiving an inactive state measurement request to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report after a user equipment has switched from the inactive state to a connected state, means for performing, upon receiving the inactive state measurement request, the at least one positioning measurement when the user equipment is in the inactive state and means for transmitting an inactive state measurement report upon switching to the connected state, the inactive state measurement report comprising information about the at least one positioning measurement performed by the user equipment. The apparatus of the second aspect may comprise the user equipment or means for controlling the user equipment.

[0008] According to a third aspect of the present invention, there is provided a first method, comprising transmitting an inactive state measurement request to a user equipment, to request the user equipment to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report upon switching from the inactive state to a connected state, receiving the inactive state measurement report from the user equipment, wherein the inactive state measurement report comprises information about the at least one positioning measurement performed by the user equipment when the user equipment was in the inactive state, generating, based at least on said information about the at least one positioning measurement performed by the user equipment, a mobility profile of the user equipment and transmitting the mobility profile of the user equipment to a base station serving the user equipment.

[0009] According to a fourth aspect of the present invention, there is provided a second method, comprising receiving an inactive state measurement request to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report after a user equipment has switched from the inactive state to a connected state, performing, upon receiving the inactive state measurement request, the at least one positioning measurement when the user equipment is in the inactive state and transmit an inactive state measurement report upon switching to the connected state, the inactive state measurement report comprising information about the at least one positioning measurement performed by the user equipment.

[0010] According to a fifth aspect of the present invention, there is provided an apparatus comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to perform, transmit an inactive state measurement request to a user equipment, to request the user equipment to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report upon switching from the inactive state to a connected state, receive the inactive state measurement report from the user equipment, wherein the inactive state measurement report comprises information about the at least one positioning measurement performed by the user equipment when the user equipment was in the inactive state, generate, based at least on said information about the at least one positioning measurement performed by the user equipment, a mobility profile of the user equipment and transmit the mobility profile of the user equipment to a base station serving the user equipment. The apparatus of the fifth aspect may comprise a location management entity or means for controlling the location management entity.

[0011] According to a sixth aspect of the present invention, there is provided an apparatus comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to perform, receive an inactive state measurement request to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report after a user equipment has switched from the inactive state to a connected state, perform, upon receiving the inactive state measurement request, the at least one positioning measurement when the user equipment is in the inactive state and transmit an inactive state measurement report upon switching to the connected state, the inactive state measurement report comprising information about the at least one positioning measurement performed by the user equipment. The apparatus of the sixth aspect may comprise the user equipment or means for controlling the user equipment. [0012] According to a seventh aspect of the present invention, there is provided a non- transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least perform the first method. According to an eighth aspect of the present invention, there is provided a non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least perform the second method.

[0013] According to a ninth aspect of the present invention, there is provided a computer program comprising instructions which, when the program is executed by an apparatus, cause the apparatus to carry out the first method. According to a tenth aspect of the present invention, there is provided a computer program comprising instructions which, when the program is executed by an apparatus, cause the apparatus to carry out the second method.

BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIGURE 1 illustrates a communication network in accordance with at least some example embodiments;

[0015] FIGURE 2 illustrates a signalling graph in accordance with at least some example embodiments;

[0016] FIGURE 3 illustrates an apparatus capable of supporting at least some example embodiments; [0017] FIGURE 4 illustrates a flow graph of a first method in accordance with at least some example embodiments;

[0018] FIGURE 5 illustrates a flow graph of a second method in accordance with at least some example embodiments.

EXAMPLE EMBODIMENTS

[0019] Positioning in cellular communication systems may be improved by the procedures described herein. More specifically, a User Equipment, UE, may perform at least one positioning measurement even if the UE would be in an inactive state. The UE may perform the at least one positioning measurement responsive to receiving an inactive state measurement request, e.g., from a location management entity. Thus, the location management entity may control how the at least one positioning measurement, if even needed, is performed in the inactive state by the UE. Upon switching to a connected state, the UE may then transmit, to a location management entity, an inactive state measurement report comprising information about the at least one positioning measurement performed by the UE. The location management entity may generate, or update, a mobility profile of the UE by taking into account said information about the at least one positioning measurement performed by the UE in the inactive state. The mobility profile may be further transmitted to a Base Station, BS, so that the BS can take actions accordingly.

[0020] FIGURE 1 illustrates a communication network in accordance with at least some example embodiments. The example communication network of FIGURE 1 may comprise UE 110, first BS 120, second BS 130 and core network 140. If cell reselection or handover of UE 110 is needed due to movement of UE 110, first BS 120 may be referred to as a source BS while second BS 130 may be referred to as a target BS. However, in some example embodiments, first BS 120 and second BS 130 may be the same, if cell reselection and handover are not needed due to movement of UE 110.

[0021] Positions of UE 110 at different time instants are denoted by points 102, 104, 106 and 108 in FIGURE 1. Using cell reselection as an example, UE 110 may be located at point 102 before the cell reselection and be in the connected state with first BS 120 via air interface 115. Then, UE 110 may start moving from point 102 towards second BS 130 via points 104 and 106. At point 108, UE 110 may have performed the cell reselection. Thus, at point 108, UE 110 may be in the connected state with second BS 130 via air interface 125. At points 104 and 106, UE 110 may be in the inactive state.

[0022] First BS 120 and second BS 130 may be connected to each other directly via wired interface 135, such as a X2 or Xn interface. First BS 120 and second BS 130 may be connected, directly or via at least one intermediate node, with core network 140 as well. Core network 140 may be, in turn, coupled via wired interface 145 with another network (not shown in FIGURE 1), via which connectivity to further networks may be obtained, for example via a worldwide interconnection network.

[0023] UE 110 may comprise or be attached to, for example, a smartphone, a cellular phone, a Machine-to-Machine, M2M, node, Machine-Type Communications node, MTC, an Internet of Things, IoT, node, a car telemetry unit, a laptop computer, a tablet computer or, indeed, any kind of suitable mobile wireless terminal or station. In some example embodiments, first BS 120 may be considered as a serving BS for UE 110 before the cell reselection, at least in the connected state at point 102, while second BS 130 may be considered as a serving BS for UE 110 after the cell reselection, at least in the connected state at point 108.

[0024] Air interface 115 between UE 110 and first BS 120 may be configured in accordance with a first Radio Access Technology, RAT, which UE 110 and first BS 120 are configured to support, and UE 110 may communicate with first BS 120 via air interface 115 using the first RAT before the cell reselection. Similarly, air interface 125 between UE 110 and second BS 130 may be configured in accordance with a second RAT, which UE 110 and second BS 130 are configured to support, and UE 110 may communicate with second BS 130 via air interface 125 using the second RAT after the cell reselection.

[0025] The first RAT and the second RAT may, or may not, be the same. Examples of cellular RATs include Long Term Evolution, LTE, New Radio, NR, which may also be known as fifth generation, 5G, radio access technology and MulteFire. For instance, in the context of LTE, a BS may be referred to as eNB while in the context of NR, a BS may be referred to as gNB. In any case, example embodiments are not restricted to any particular wireless technology. Instead, example embodiments may be exploited in any cellular communication network wherein it is desirable to enhance positioning. [0026] In general, positioning may be used to improve performance of a communication network. In case of cellular communication networks, positioning information of UEs may be exploited at least to improve for network efficiency. By knowing, or predicting, the position of UE 110 along the route from point 102 to 108, the network can optimize its resource usage. For instance, resource allocation may be optimized by predicting future position(s) of UE 110, which allows first BS 120 and/or second BS 130 to adapt for example a modulation and coding scheme, bandwidth and/or numerology to channel and cell load conditions.

[0027] In addition, a carrier frequency offset may be pre-compensated by utilizing positioning information of UE 110. Positioning information of UE 110 may be referred to as information about positioning measurements performed by UE 110, such as time-of- arrival, a strength of a received signal and/or an angle-of-arrival of reference signals. At least high speed UEs suffer from large Doppler shifts, which, unless accounted for, may severely degrade the quality of the data reception in both, uplink and downlink. Positioning information may also be used for interference, handover and cell reselection management. Moreover, many applications require and/or benefit from accurate tracking of the position of UEs, especially the high speed UEs. There is therefore a need to ensure accurate positioning in cellular communication networks in general.

[0028] Accurate tracking of positions of UEs may become a challenging task if UE 110 is in the inactive state though. A UE in the inactive state is typically not able to process and report information about positioning measurements, such as information about measurements of positioning reference signals, as there are no means for scheduling the reporting for UEs in the inactive state. Thus, the accuracy of positioning of a UE in the inactive state would be degraded. Especially in case of high speed UEs, such as UEs in trains or cars, the position may change drastically during the inactive state and hence the tracking of the position of such UEs needs to be improved to avoid compromising subsequent resource optimization, for example at second BS 130 in case of cell reselection. If the network does not know an exact position of such a UE when the UE switches from the inactive state to the connected state, the network would need to perform resource allocation and dimensioning of the data transmission in a very conservative manner, especially if the most recent channel conditions were not particularly favourable for the UE. Thus, a robust modulation and coding scheme, and potentially a lower numerology as well, may need to be chosen which would not be optimal in all cases. In general, the inactive state may refer to the Radio Resource Control, RRC, inactive state and the connected state may refer to the RRC connected state, at least in case of 3rd Generation Partnership Project, 3GPP, standards.

[0029] Example embodiments of the present invention therefore enhance tracking of positions of UEs by improving accuracy of positioning for UEs which switch from the inactive state to the connected state. Mobility management may be thus improved by enhancing tracking of positions of UEs in the inactive state. The inactive state is a state between the idle mode and the connected state, to reduce signalling load and creation/cancellation of tunnels between a radio network, comprising for example first BS 120 and second BS 130, and core network 140. In the inactive state, logical signalling link and tunnel of a UE to the core network are kept in place but the connection of the UE to the radio network is released.

[0030] More specifically, UE 110 may report to the network a history of its past positions during the last inactive period, i.e., when UE 110 was in the inactive state at points 104 and 106 in FIGURE l. UE 110 may report the history ofits past positions by transmitting an inactive state measurement report comprising information about at least one positioning measurement, which it has performed in the inactive state. UE 110 may transmit the inactive state measurement report upon awakening from the inactive state, i.e., upon switching from the inactive state to the connected state. Subsequently, a location management entity, such as a Location Management Function, LMF, in core network 140, may use said information about the at least one positioning measurement in the inactive state measurement report to generate a Mobility Profile, MProf, of UE 110. The LMF may for example generate the MProf of UE 110 by updating a previous MProf of UE 110 according to said information about the at least one positioning measurement. Information about a positioning measurement may for example comprise at least one of a time stamp indicating when the measurement was performed (time-of-arrival), a strength of a received signal (Reference Signal Received Power, RSRP), an angle-of-arrival and an indication about a measured cell- specific reference signal (Synchronization Signal Block, SSB).

[0031] The LMF in core network 140 may for example compute and update the MProf of UE 110. For instance, the MProf may consist of a set of parameters characterizing mobility pattern of UE 110, e.g., speed, direction of movement, acceleration, etc. These parameters may be obtained via UE 110 itself (UE 110 may, e.g., report sensor information) or estimated using the channel state information and past position estimates via a serving BS.

[0032] The LMF may then transmit the MProf of UE 110 to second BS 130. The MProf of UE 110, computed from the inactive state measurement report, may then be used by second BS 130, to predict direction of movement, future positions and velocity of UE 110, e.g., during the current Radio Resource Control, RRC, connected window. The MProf of UE 110 may define displacement of UE 110 between two time instances, such as points 102 and 108 in FIGURE 1, depending on velocity of UE 110 and acceleration vector. For instance, an inactive period of 2.5s in the connected state at 500 km/h uniform movement equals a travelled distance of 350 m. The MProf of UE 110 may be used by second SB 130 for enhanced mobility management (e.g. RA and predicted carrier frequency offset for potential pre-compensation).

[0033] Example embodiments of the present invention may be used for example to enhance LTE Positioning Protocol, LPP, and New Radio Positioning Protocol Annex, NRPPa, positioning protocols, to make it possible for UE 110 to report information about positioning measurements performed in the inactive state for example on SSBs. SSBs are cell-specific reference signals which first BS 120 and second BS 130 may broadcast to enable UEs in the network to perform beam selection and periodic realignments. Typical usage of SSBs at UEs consists of periodic measurements of the RSRPs of SSBs of all detectable BSs and reporting the indices of the best SSBs back to a serving BS. In some example embodiments, the usage of SSBs may be extended to tracking positions of UE 110.

[0034] FIGURE 2 illustrates a signalling graph in accordance with at least some example embodiments. On the vertical axes are disposed, from the left to the right, UE 110, first BS 120 (BS1), second BS 130 (BS2) and the LMF in core network 140 of FIGURE 1. Time advances from the top towards the bottom. Even though the LMF in core network 140 is used as an example in FIGURE 2, the steps of the LMF may be performed by any location management entity in general.

[0035] At optional step 202, the LMF in core network 140 may determine that UE 110 needs to perform at least one positioning measurement in the inactive state. The LMF may thus evaluate whether UE 110 needs position tracking for inactive-mode periods, i.e., evaluate positioning related requirements of UE 110, or a user of UE 110. Said determination at step 202 may be based on at least one of a type of UE 110 (obtained from the e.g. vehicular, Hot, etc), a location accuracy requirement (application dependent), location integrity requirement (application dependent) and a previous MProf of UE 110. The accuracy and latency of positioning may be dictated by a service that requests positioning in the first place. So, for example, robots in a factory may need to be localized very often and very accurately. As another example, virtual reality and extended reality applications may also have high accuracy and latency requirements.

[0036] For instance, a BS may know types of UEs that it is serving and can estimate the UE mobility (e.g. Doppler estimation, channel state information reports). Based on this information, the serving BS may decide how often the mobility profiles of the UEs it serves need to be updated. Note that the BS may use implicitly this type of approach for RRM, handover or cell reselection purposes.

[0037] At step 204, the LMF in core network 140 may transmit an inactive state measurement request to UE 110, to request UE 110 to perform at least one positioning measurement in the inactive state and transmit an inactive state measurement report comprising information about the at least one positioning measurement performed by UE 110 when UE 110 was in the inactive state. The LMF may for example transmit the inactive state measurement request upon determining that the evaluation result is positive at step 202, i.e., upon determining that UE 110 needs to perform positioning measurements in the inactive state.

[0038] The LMF may configure UE 110 using the inactive state measurement request. For instance, the inactive state measurement request may comprise at least one indication of a measurement rate, a location of at least one cell-specific reference signal for performing the at least one position measurement and a duration of positioning measurements within an inactive period. More specifically, the measurement rate may refer to performing and collecting measurements at a given rate R, i.e., how often the positioning measurements are collected, for example by measuring a certain SSB. If UE 110 is static or moving very slow, the LMF may configure a low rate since it does not expect that the positioning measurements would change significantly over short period of time. Thus, performance may be optimized as unnecessary measurements are avoided.

[0039] Alternatively, or in addition, the LMF may avoid unnecessary measurements by transmitting the indication about the location of at least one cell-specific reference signal for performing the at least one position measurement. The indication about the location of at least one cell-specific reference signal may refer to SSB position measurements on a certain SSB resource (time/frequency resource), e.g., time-of-arrival and/or angle-of-arrival in addition to RSRP. In some example embodiments, the LMF may configure a subset of best cell-specific reference signals.

[0040] Alternatively, or in addition, the LMF may avoid unnecessary measurements by transmitting the indication about a duration of positioning measurements within an inactive period. The LMF may determine that UE 110 does not need to perform measurements all the time while UE 110 is in the inactive state. For example, if it is predicted that the route of UE 110 is known in the beginning of the inactive state (e.g., UE 110 is in a train), there may be no need to perform measurements in the beginning of the inactive state. The connected state may be resumed upon request from upper layers, and initiated by either UE 110 or a BS.

[0041] At optional step 206, UE 110 may transmit a resource allocation request to first BS 120, and/or possibly to second BS 130 if known, for example to request first BS 120 to allocate resources in the next, first Atime slots upon switching from the inactive state to the connected state. The resource allocation request may be transmitted to request allocation of resources for transmission of the inactive state measurement report. Alternatively, the LMF may transmit the resource allocation request to first BS 120 and/or second BS 130, for example over NRPPa, in a message exchange transparent to UE 110.

[0042] The resource allocation request comprises an inactive state tracking flag, an indication about a size of an expected inactive state measurement report (payload of the inactive state measurement report) and/or an urgency flag (i.e. how soon after awakening the UE needs to report the inactive state measurement report.

[0043] For example, the size of the expected inactive state measurement report may be used for allocating resources properly for transmission of the inactive state measurement report by first BS 120 and/or second BS 130. As the size of the expected inactive state measurement report can be taken into account when allocating resources, it may be ensured that with high probability the report fits to the allocated resource and hence unnecessary signalling can be avoided, because one transmission is enough. At the same, there is no need to allocate resources excessively. [0044] Concerning the urgency flag, “ urgency-flag = 1 ” may mean UE 110 may delay transmission of the inactive state measurement report by 0 slots, urgency-flag=2” may mean a delay of A slots, etc. The mapping between the flag index and the supported delay may be agreed between the LMF, UE 110 and the serving BS beforehand. The urgency flag indicates to a BS how long UE 110 can delay the transmission of the report. Based on this flag, the BS may allocate resources to the UE to send this report.

[0045] At optional step 208, first BS 120 may grant the resource allocation request and inform UE 110 about a resource, such as a random access resource, for transmission of the inactivity report upon switching from the inactivity mode to the connected state. For instance, first BS 120 may configure the resource for transmission of the inactivity report and transmit a reconfiguration in an RRC message, e.g., by setting pointers to a start and end of a transmission slot. UE 110 may, at steps 202 - 208, be in connected state with first BS 120, and switch to inactive state after step 208.

[0046] At optional step 210, first BS 102 may transmit an indication about UE 110, which has switched to the inactive state from the connected state, to the LMF. The indication about UE 110 may be transmitted over a backhaul link, such as interface 135 in FIGURE 1, using NRPPa protocol for example. UE 110 which has switched to the inactive state from the connected state may be decided by the LMF and indicated to first BS 120 before step 210. In some example embodiments, the indication may refer to a set of UEs and the LMF may indicate the set periodically to first BS 120, and possibly to second BS 130 as well.

[0047] At step 212, UE 110 may, upon receiving the inactive state measurement request, perform positioning measurement according to the inactive measurement report request. That is to say, UE 110 may perform positioning measurement in the inactive state according to the measurement rate, the measurement duration and/or the location of at least one cell-specific reference signal for performing the at least one position measurement, i.e., on an indicated SSB. While being in the inactive state, UE 110 may listen to at least one cell-specific reference signal, such as beam management signals like SSBs, from all available BSs. For instance, UE 110 may perform the requested at least one positioning measurement on a detected SSB. Positioning measurements on SSBs may comprise measuring at least one of a time-of-arrival, a strength of a received signal and/or an angle- of-arrival of the best SSBs in the given SSB burst, as indicated by the LMF. [0048] In some example embodiments, a FIFO storage may be utilized at UE 110 to compensate memory limitations of UE 110. As such, UE 110 does not have to store positioning measurements indefinitely since they will become deprecated after a period of time proportional to mobility, e.g., velocity, of UE 110. The size of the FIFO storage may be dimensioned according to the UE type of UE 110 for example. Each measurement may be logged by UE 110 in the inactive measurement report in a FIFO list like below:

[0049] At step 214, UE 110 may generate the inactive state measurement report by adding information about the at least positioning measurement performed by UE 110 to the inactive state measurement report. For instance, said information about the at least one positioning measurement may comprise a time-of-arrival, a strength of a received signal, an angle-of-arrival and/or an indication of the measured cell-specific reference signal.

[0050] At steps 210 - 214, UE 110 may be in the inactive state and switch to the connected state after step 214. At step 216, UE 110 may transmit the inactive state measurement report to the LMF, wherein the inactive state measurement report comprises said information about the at least one positioning measurement performed by UE 110 when UE 110 was in the inactive state (steps 210 - 214). For instance, UE 110 may report to the LMF, possibly via second BS 130, the inactive state measurement report comprising a list of positioning measurements on SSBs collected by UE 110 while UE 110 was in the inactive state.

[0051] In some example embodiments, UE 110 may transmit an inactive state measurement report table, upon switching from inactive state to connected state, using the resource allocated and indicated at step 208. UE 110 may transmit the inactive state measurement report by appending the report to a standard positioning report as configured by the serving BS during LPP. The report may be sent via the serving BS over a regular control channel but it is transparent to the serving BS, because the serving BS acts as a relay to the LMF.

[0052] Upon receiving the inactive state measurement report, the LMF in core network 140 may generate, or update, the MProf of UE 110 at step 218. For instance, the MProf of UE 110 may comprise information about expected current and future displacements of UE 110, based on for example an estimated velocity and acceleration vectors.

[0053] At step 220, the LMF may transmit the generated, or updated, MProf of UE 110 to second BS 130, i.e., to the BS serving UE 110 in connected state after UE 110 has switched from the inactive state to the connected state. The generated, or updated, MProf of UE 110 may be transmitted to second BS 130 to be used in mobility management for the next Y slots of RRC connected state. The LMF may also convey to BS 130 a list of predicted positions of UE 110 for the future Y slots. The generated, or updated, MProf of UE 110 may be transmitted over NRPPa.

[0054] At step 222, second BS 130 may use the MProf of UE 110 for enhanced mobility management.

[0055] FIGURE 3 illustrates an apparatus capable of supporting at least some example embodiments. Illustrated is device 300, which may comprise, for example, the LMF in core network 140 or UE 110, or a device controlling functioning thereof. Comprised in device 300 is processor 310, which may comprise, for example, a single- or multi-core processor wherein a single-core processor comprises one processing core and a multi -core processor comprises more than one processing core. Processor 310 may comprise, in general, a control device. Processor 310 may comprise more than one processor. Processor 310 may be a control device. A processing core may comprise, for example, a Cortex-A8 processing core manufactured by ARM Holdings or a Steamroller processing core produced by Advanced Micro Devices Corporation. Processor 310 may comprise at least one Qualcomm Snapdragon and/or Intel Atom processor. Processor 310 may comprise at least one Application-Specific Integrated Circuit, ASIC. Processor 310 may comprise at least one Field-Programmable Gate Array, FPGA. Processor 310 may be means for performing method steps in device 300. Processor 310 may be configured, at least in part by computer instructions, to perform actions. [0056] A processor may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with example embodiments described herein. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0057] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0058] Device 300 may comprise memory 320. Memory 320 may comprise random- access memory and/or permanent memory. Memory 320 may comprise at least one RAM chip. Memory 320 may comprise solid-state, magnetic, optical and/or holographic memory, for example. Memory 320 may be at least in part accessible to processor 310. Memory 320 may be at least in part comprised in processor 310. Memory 320 may be means for storing information. Memory 320 may comprise computer instructions that processor 310 is configured to execute. When computer instructions configured to cause processor 310 to perform certain actions are stored in memory 320, and device 300 overall is configured to run under the direction of processor 310 using computer instructions from memory 320, processor 310 and/or its at least one processing core may be considered to be configured to perform said certain actions. Memory 320 may be at least in part comprised in processor 310. Memory 320 may be at least in part external to device 300 but accessible to device 300. [0059] Device 300 may comprise a transmitter 330. Device 300 may comprise a receiver 340. Transmitter 330 and receiver 340 may be configured to transmit and receive, respectively, information in accordance with at least one cellular or non-cellular standard. Transmitter 330 may comprise more than one transmitter. Receiver 340 may comprise more than one receiver. Transmitter 330 and/or receiver 340 may be configured to operate in accordance with Global System for Mobile communication, GSM, Wideband Code Division Multiple Access, WCDMA, 5G, Long Term Evolution, LTE, IS-95, Wireless Local Area Network, WLAN, Ethernet and/or Worldwide Interoperability for Microwave Access, WiMAX, standards, for example.

[0060] Device 300 may comprise a Near-Field Communication, NFC, transceiver 350. NFC transceiver 350 may support at least one NFC technology, such as Bluetooth, Wibree or similar technologies.

[0061] Device 300 may comprise User Interface, UI, 360. UI 360 may comprise at least one of a display, a keyboard, a touchscreen, a vibrator arranged to signal to a user by causing device 300 to vibrate, a speaker and a microphone. A user may be able to operate device 300 via UI 360, for example to accept incoming telephone calls, to originate telephone calls or video calls, to browse the Internet, to manage digital files stored in memory 320 or on a cloud accessible via transmitter 330 and receiver 340, or via NFC transceiver 350, and/or to play games.

[0062] Device 300 may comprise or be arranged to accept a user identity module 370. User identity module 370 may comprise, for example, a Subscriber Identity Module, SIM, card installable in device 300. A user identity module 370 may comprise information identifying a subscription of a user of device 300. A user identity module 370 may comprise cryptographic information usable to verify the identity of a user of device 300 and/or to facilitate encryption of communicated information and billing of the user of device 300 for communication effected via device 300.

[0063] Processor 310 may be furnished with a transmitter arranged to output information from processor 310, via electrical leads internal to device 300, to other devices comprised in device 300. Such a transmitter may comprise a serial bus transmitter arranged to, for example, output information via at least one electrical lead to memory 320 for storage therein. Alternatively to a serial bus, the transmitter may comprise a parallel bus transmitter. Likewise processor 310 may comprise a receiver arranged to receive information in processor 310, via electrical leads internal to device 300, from other devices comprised in device 300. Such a receiver may comprise a serial bus receiver arranged to, for example, receive information via at least one electrical lead from receiver 340 for processing in processor 310. Alternatively to a serial bus, the receiver may comprise a parallel bus receiver.

[0064] Device 300 may comprise further devices not illustrated in FIGURE 3. For example, where device 300 comprises a smartphone, it may comprise at least one digital camera. Some devices 300 may comprise a back-facing camera and a front-facing camera, wherein the back-facing camera may be intended for digital photography and the front- facing camera for video telephony. Device 300 may comprise a fingerprint sensor arranged to authenticate, at least in part, a user of device 300. In some example embodiments, device 300 lacks at least one device described above. For example, some devices 300 may lack a NFC transceiver 350 and/or user identity module 370.

[0065] Processor 310, memory 320, transmitter 330, receiver 340, NFC transceiver 350, UI 360 and/or user identity module 370 may be interconnected by electrical leads internal to device 300 in a multitude of different ways. For example, each of the aforementioned devices may be separately connected to a master bus internal to device 300, to allow for the devices to exchange information. However, as the skilled person will appreciate, this is only one example and depending on the example embodiment various ways of interconnecting at least two of the aforementioned devices may be selected without departing from the scope of the example embodiments.

[0066] FIGURE 4 illustrates a flow graph of a first method in accordance with at least some example embodiments. The phases of the illustrated first method may be performed by the LMF in core network 140, or by a control device configured to control the functioning thereof, possibly when installed therein.

[0067] The first method may comprise, at step 410, transmitting an inactive state measurement request to a user equipment, to request the user equipment to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report upon switching from the inactive state to a connected state. At step 420, the first method may comprise receiving the inactive state measurement report from the user equipment, wherein the inactive state measurement report comprises information about the at least one positioning measurement performed by the user equipment when the user equipment was in the inactive state. Moreover, at step 430, the first method may comprise generating, based at least on said information about the at least one positioning measurement performed by the user equipment, a mobility profile of the user equipment. Finally, at step 440, the first method may comprise transmitting the mobility profile of the user equipment to a base station serving the user equipment.

[0068] FIGURE 5 illustrates a flow graph of a second method in accordance with at least some example embodiments. The phases of the illustrated second method may be performed by UE 110, or by a control device configured to control the functioning thereof, possibly when installed therein.

[0069] The second method may comprise, at step 510, receiving an inactive state measurement request to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report after a user equipment has switched from the inactive state to a connected state. At step 520, the second method may comprise performing, upon receiving the inactive state measurement request, the at least one positioning measurement when the user equipment is in the inactive state. Finally, at step 530, the second method may comprise transmitting an inactive state measurement report upon switching to the connected state, the inactive state measurement report comprising information about the at least one positioning measurement.

[0070] It is to be understood that the example embodiments disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular example embodiments only and is not intended to be limiting.

[0071] Reference throughout this specification to one example embodiment or an example embodiment means that a particular feature, structure, or characteristic described in connection with the example embodiment is included in at least one example embodiment. Thus, appearances of the phrases “in one example embodiment” or “in an example embodiment” in various places throughout this specification are not necessarily all referring to the same example embodiment. Where reference is made to a numerical value using a term such as, for example, about or substantially, the exact numerical value is also disclosed. [0072] As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various example embodiments and examples may be referred to herein along with alternatives for the various components thereof. It is understood that such example embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations.

[0073] In an example embodiment, an apparatus, such as, for example, the LMF in core network 140 or UE 110, or a control device configured to control the functioning thereof, may comprise means for carrying out the example embodiments described above and any combination thereof.

[0074] In an example embodiment, a computer program may be configured to cause a method in accordance with the example embodiments described above and any combination thereof. In an example embodiment, a computer program product, embodied on a non-transitory computer readable medium, may be configured to control a processor to perform a process comprising the example embodiments described above and any combination thereof.

[0075] In an example embodiment, an apparatus, such as, for example the LMF in core network 140 or UE 110, or a control device configured to control the functioning thereof, may comprise at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform the example embodiments described above and any combination thereof.

[0076] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more example embodiments. In the preceding description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of example embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0077] While the forgoing examples are illustrative of the principles of the example embodiments in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

[0078] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of “a” or “an”, that is, a singular form, throughout this document does not exclude a plurality. INDUSTRIAL APPLICABILITY

[0079] At least some example embodiments find industrial application in cellular communication networks, such as in 5G/NR networks, wherein it is desirable to improve tracking of positions of UEs.

ACRONYMS LIST

3 GPP 3^rd Generation Partnership Project ASIC Application-Specific Integrated Circuit BS Base Station

FPGA Field-Programmable Gate Array

GSM Global System for Mobile communication

IoT Internet of Things

LMF Location Management Function

LPP LTE Positioning Protocol

LTE Long-Term Evolution

M2M Machine-to-Machine

MAC Media Access Control

MProf Mobility Profile

MTC Machine-Type Communications

NFC Near-Field Communication

NR New Radio

NRPPa New Radio Positioning Protocol Annex

RAN Radio Access Network

RAT Radio Access Technology

RRC Radio Resource Control

RSRP Reference Signal Received Power

SIM Subscriber Identity Module

SSB Synchronization Signal Block

UE User Equipment

UI User Interface

WCDMA Wideband Code Division Multiple Access

WLAN Wireless Local Area Network

WiMAX Worldwide Interoperability for Microwave Access REFERENCE SIGNS LIST

Claims

CLAIMS:

1. An apparatus, comprising:

- means for transmitting an inactive state measurement request to a user equipment, to request the user equipment to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report upon switching from the inactive state to a connected state;

- means for receiving the inactive state measurement report from the user equipment, wherein the inactive state measurement report comprises information about the at least one positioning measurement performed by the user equipment when the user equipment was in the inactive state;

- means for generating, based at least on said information about the at least one positioning measurement performed by the user equipment, a mobility profile of the user equipment; and

- means for transmitting the mobility profile of the user equipment to a base station serving the user equipment.

2. An apparatus according to claim 1, wherein the user equipment is in the connected state when the inactive state measurement report is received by the apparatus.

3. An apparatus according to claim 2, wherein the inactive state measurement request comprises an indication about measurement rate and/or an indication about a duration of requested positioning measurements within an inactive period.

4. An apparatus according to any of the preceding claims, wherein the inactive state measurement request comprises an indication about a location of at least one cell-specific reference signal for performing the at least one positioning measurement.

5. An apparatus according to any of the preceding claims, further comprising:

- means for determining that the user equipment needs to perform the at least one positioning measurement in the inactive state, wherein said determination is based on at least one of a type of the user equipment, a location accuracy requirement, a location integrity requirement and a previous mobility profile of the user equipment; and

- transmitting the inactive state measurement request responsive to said determination.

6. An apparatus according to any of the preceding claims, further comprising:

- means for transmitting a resource allocation request to the base station, to request allocation of resources for transmission of the inactive state measurement report, wherein the resource allocation request comprises an inactive state tracking flag, an indication about a size of an expected inactive state measurement report and/or an urgency flag.

7. An apparatus, comprising:

- means for receiving an inactive state measurement request to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report after a user equipment has switched from the inactive state to a connected state;

- means for performing, upon receiving the inactive state measurement request, the at least one positioning measurement when the user equipment is in the inactive state; and

- means for transmitting an inactive state measurement report upon switching to the connected state, the inactive state measurement report comprising information about the at least one positioning measurement performed by the user equipment.

8. An apparatus according to claim 7, wherein the user equipment is in the connected state when the inactive state measurement report is transmitted by the apparatus.

9. An apparatus according to claim 8, wherein the inactive state measurement request comprises an indication about a measurement rate and/or an indication about a duration of requested positioning measurements within an inactive period.

10. An apparatus according to any of claims 7 to 9, wherein the inactive state measurement request comprises an indication about a location of at least one cell-specific reference signal for performing the at least one positioning measurement.

11. An apparatus according to any of claims 7 to 10, further comprising:

- means for transmitting a resource allocation request to a base station, to request allocation of resources for transmission of the inactive state measurement report, wherein the resource allocation request comprises an inactive state tracking flag, an indication about a size of an expected inactive state measurement report and/or an urgency flag.

12. An apparatus according to any of claims 7 to 11, wherein the apparatus comprises the user equipment or means for controlling the user equipment.

13. A method comprising:

- transmitting an inactive state measurement request to a user equipment, to request the user equipment to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report upon switching from the inactive state to a connected state;

- receiving the inactive state measurement report from the user equipment, wherein the inactive state measurement report comprises information about the at least one positioning measurement performed by the user equipment when the user equipment was in the inactive state;

- generating, based at least on said information about the at least one positioning measurement performed by the user equipment, a mobility profile of the user equipment; and

- transmitting the mobility profile of the user equipment to a base station serving the user equipment.

14. A method comprising:

- receiving an inactive state measurement request to perform at least one positioning measurement in an inactive state and to transmit an inactive state measurement report after a user equipment has switched from the inactive state to a connected state;

- performing, upon receiving the inactive state measurement request, the at least one positioning measurement when the user equipment is in the inactive state; and - transmitting an inactive state measurement report upon switching to the connected state, the inactive state measurement report comprising information about the at least one positioning measurement. A computer program configured to perform a method according to claim 13 or claim 14.