Storing measurement result

Abstract

Disclosed is a method comprising receiving, from a first network device controlling a first cell, a measurement configuration for a first measurement type, wherein the measurement configuration indicates at least one condition for triggering a cell change; determining, based on at least one measurement result of the first measurement type, whether the at least one condition is fulfilled; based on determining that the at least one condition is fulfilled, storing at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type; executing the cell change from the first cell to a second cell; and reporting, to a second network device controlling the second cell, based on completing the cell change, the at least one measurement result of the first measurement type, and the at least one measurement result of the second measurement type.

Description

ISTORING MEASUREMENT RESULTFIELD

[0001] The following example embodiments relate to wireless communication.BACKGROUND

[0002] In wireless communication, the user equipment may perform and report various signal measurements. These reports may help the network to make decisions about resource management, handovers, and / or maintaining service quality.SUMMARY

[0003] The scope of protection sought for various example embodiments is set out by the claims. The example embodiments and features, if any, described in this specification that do not fall under the scope of the claims are to be interpreted as examples useful for understanding various embodiments.

[0004] Other features and advantages of the embodiments of the present disclosure will also be apparent from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of embodiments of the disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] In the following, various example embodiments will be described in greater detail with reference to the accompanying drawings, in whichFIG. 1 A illustrates an example of a wireless communication network;FIG. 1 B illustrates an example of a system;FIG. 2 illustrates a comparison between layer 1 measurements and layer 3 measurements; FIG. 3 illustrates an example embodiment for layer 1 and layer 3 measurement sample reporting;FIG. 4 illustrates a signal flow diagram;FIG. 5 illustrates a signal flow diagram.FIG. 6 illustrates a signal flow diagram;FIG. 7 illustrates a signal flow diagram;FIG. 8 illustrates a flow chart;FIG. 9 illustrates a flow chart;FIG. 10 illustrates a flow chart;FIG. 11 illustrates a flow chart;FIG. 12 illustrates an example of an apparatus; andFIG. 13 illustrates an example of an apparatus.DETAILED DESCRIPTION

[0006] The following embodiments are exemplifying. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments within the scope of the claims. Furthermore, the words "comprising" and "including" should be understood as not limiting the described embodiments to consist of only those features that have been mentioned, and such embodiments may also contain features that have not been specifically mentioned. Reference numbers, in the description and / or in the claims, serve to illustrate the embodiments with reference to the drawings, without limiting the embodiments to these examples only.

[0007] Further, it should be appreciated that, as used herein, the terms “the at least one” and “the one or more” mean “any one of the at least one” and “any one of the one or more”, respectively. Furthermore, as used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0008] Some example embodiments described herein may be implemented in a wireless communication network comprising a radio access network based on one or more of the following radio access technologies (RATs): global system for mobile communications (GSM) or any other second generation (2G) radio access technology, universal mobile telecommunication system (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), long term evolution (LTE), LTE-Advanced, fourth generation (4G), fifth generation (5G), 5G new radio (NR), 5G-Advanced (i.e., 3GPP NR Rel-18 and beyond), sixth generation (6G), or seventh generation (7G). Some examples of radio access networks include the universal mobile telecommunications system (UMTS) radio access network (UTRAN), the evolved universal terrestrial radio access network (E-UTRA), or the next generation radio access network (NG-RAN). The wireless communication network may further comprise a core network, and some example embodiments may also be applied to network functions of the core network.

[0009] It should be noted that the embodiments are not restricted to the wireless communication network given as an example, but a person skilled in the art may also apply the solution to other wireless communication networks or systems provided with necessary properties. For example, some example embodiments may also be applied to a communication system based on IEEE 802.11 specifications, or a communication system based on IEEE 802.15 specifications. IEEE is an abbreviation for the Institute of Electrical and Electronics Engineers.

[0010] FIG. 1A depicts an example of a simplified wireless communication network showing some physical and logical entities. The connections shown in FIG. 1 A may be physical connections or logical connections. It is apparent to a person skilled in the art that the wireless communication network may also comprise other physical and logical entities than those shown in FIG. 1 A.

[0011] The example embodiments described herein are not, however, restricted to the wireless communication network given as an example but a person skilled in the art may apply the example embodiments described herein to other wireless communication networks provided with necessary properties.

[0012] The example wireless communication network shown in FIG. 1 A includes a radio access network (RAN) and a core network 110.

[0013] FIG. 1 A shows user equipment (UE) 100, 102 configured to be in a wireless connection on one or more communication channels in a radio cell with an access node 104 of a radio access network.

[0014] The access node 104 may comprise a computing device configured to control the radio resources of the access node 104 and to be in a wireless connection with one or more UEs 100, 102. The access node 104 may also be referred to as a base station, a base transceiver station (BTS), an access point, a cell site, a network node, a radio access network node, a RAN node, or a network device.

[0015] The access node 104 may be, for example, an evolved NodeB (abbreviated as eNB or eNodeB), or a next generation evolved NodeB (abbreviated as ng-eNB), or a next generation NodeB (abbreviated as gNB or gNodeB), providing the radio cell. The access node 104 may include or be coupled to transceivers. From the transceivers of the access node 104, a connection may be provided to an antenna unit that establishes a bi-directional radio link to one or more UEs 100, 102. The antenna unit may comprise an antenna or antenna element, or a plurality of antennas or antenna elements.

[0016] The wireless connection (e.g., radio link) from a UE 100, 102 to the access node 104 may be called uplink (UL) or reverse link, and the wireless connection (e.g., radio link) from the access node 104 to the UE 100, 102 may be called downlink (DL) or forward link. A UE 100 may also communicate directly with another UE 102, and vice versa, via a wireless connection generally referred to as a sidelink (SL). It should be appreciated that the access node 104 or its functionalities may be implemented by using any node, host, server, access point or other entity suitable for providing such functionalities.

[0017] The radio access network may comprise more than one access node 104, in which case the access nodes may also be configured to communicate with one another over wired or wireless links. These links between access nodes may be used for sending and / or receiving control plane signaling and also for routing data from one access node to another access node.

[0018] The access node 104 may further be connected to a core network (CN) 110. The core network 110 may comprise an evolved packet core (EPC) network and / or a 5thgeneration core network(5GC). The EPC may comprise network entities, such as a serving gateway (S-GW for routing and forwarding data packets), a packet data network gateway (P-GW) for providing connectivity of UEs to external packet data networks, and / or a mobility management entity (MME). The 5GC may comprise one or more network functions, such as at least one of: a user plane function (UPF), an access and mobility management function (AMF), a location management function (LMF), and / or a session management function (SMF).

[0019] The core network 110 may also be able to communicate with one or more external networks 113, such as a public switched telephone network or the Internet, or utilize services provided by them. For example, in 5G wireless communication networks, the UPF of the core network 110 may be configured to communicate with an external data network via an N6 interface. In LTE wireless communication networks, the P-GW of the core network 110 may be configured to communicate with an external data network.

[0020] It should also be understood that the distribution of functions between core network operations and access node operations may differ in future wireless communication networks compared to that of the LTE or 5G, or even be non-existent.

[0021] The illustrated UE 100, 102 is one type of an apparatus to which resources on the air interface may be allocated and assigned. The UE 100, 102 may also be called a wireless communication device, a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, a terminal device, or a user device, just to mention but a few names. The UE 100, 102 may be a computing device operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of computing devices: a mobile phone, a smartphone, a personal digital assistant (PDA), a handset, a computing device comprising a wireless modem (e.g., an alarm or measurement device, etc.), a laptop computer, a desktop computer, a tablet, a game console, a notebook, a multimedia device, a reduced capability (RedCap) device, a wearable device (e.g., a watch, earphones or eyeglasses) with radio parts, a household appliance with radio parts, a sensor comprising a wireless modem, or a computing device comprising a wireless modem integrated in a vehicle or in a house.

[0022] It should be appreciated that the UE 100, 102 may also be a nearly exclusive uplink-only device, of which an example may be a camera or video camera loading images or video clips to a network. The UE 100, 102 may also be a device having capability to operate in an Internet of Things (loT) network, which is a scenario in which objects may be provided with the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction.

[0023] The wireless communication network may also be able to support the usage of cloud services. For example, at least part of core network operations may be carried out as a cloud service (this is depicted in FIG. 1A by “cloud” 114). The UE 100, 102 may also utilize the cloud 114. In some applications, the computation for a given UE may be carried out in the cloud 114 or in another UE.

[0024] The wireless communication network may also comprise a central control entity, such as a network management system (NMS), or the like. The NMS is a centralized suite of software and hardware used to monitor, control, and administer the network infrastructure. The NMS is responsible for a wide range of tasks such as fault management, configuration management, security management, performance management, and accounting management. The NMS enables network operators to efficiently manage and optimize network resources, ensuring that the network delivers high performance, reliability, and security.

[0025] 5G enables using multiple-input and multiple-output (MIMO) antennas in the access node 104 and / or the UE 100, 102, many more base stations or access nodes than an LTE network (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and employing a variety of radio technologies depending on service needs, use cases and / or spectrum available. 5G wireless communication networks may support a wide range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine-type applications, such as (massive) machine-type communications (mMTC), including vehicular safety, different sensors and real-time control.

[0026] In 5G wireless communication networks, access nodes and / or UEs may have multiple radio interfaces, such as below 6 gigahertz (GHz), centimeter wave (cmWave) and millimeter wave (mmWave), and also being integrable with legacy radio access technologies, such as LTE. Integration with LTE may be implemented, for example, as a system, where macro coverage may be provided by LTE, and 5G radio interface access may come from small cells by aggregation to LTE. In other words, a 5G wireless communication network may support both inter-RAT operability (such as interoperability between LTE and 5G) and inter-RI operability (inter-radio interface operability, such as between below 6GHz, cmWave, and mmWave).

[0027] 5G wireless communication networks may also apply network slicing, in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the same physical infrastructure to run services that have different requirements on latency, reliability, throughput and mobility.

[0028] In one embodiment, an access node 104 may comprise: a radio unit (RU) 103 comprising a radio transceiver (TRX), i.e., a transmitter (Tx) and a receiver (Rx); one or more distributed units (DUs) 105 that may be used for the so-called Layer 1 (L1) processing and real-time Layer 2 (L2) processing; and a central unit (CU) 108 (also known as a centralized unit) that may be used for non-real-time L2 and Layer 3 (L3) processing. The CU 108 may be connected to the one or more DUs 105 for example via an F1 interface. Such an embodiment of the access node 104 may enable the centralization of CUs relative to the cell sites and DUs, whereas DUs may be more distributed and may even remain at cell sites. The CU and DU togethermay also be referred to as baseband or a baseband unit (BBU). The CU and DU may also be comprised in a radio access point (RAP).

[0029] The CU 108 may be a logical node hosting radio resource control (RRC), service data adaptation protocol (SDAP) and / or packet data convergence protocol (PDCP), of the NR protocol stack for an access node 104. The CU 108 may comprise a control plane (CU-CP), which may be a logical node hosting the RRC and the control plane part of the PDCP protocol of the NR protocol stack for the access node 104. The CU 108 may further comprise a user plane (CU-UP), which may be a logical node hosting the user plane part of the PDCP protocol and the SDAP protocol of the CU for the access node 104.

[0030] The DU 105 may be a logical node hosting radio link control (RLC), medium access control (MAC) and / or physical (PHY) layers of the NR protocol stack for the access node 104. The operations of the DU 105 may be at least partly controlled by the CU 108. It should also be understood that the distribution of functions between the DU 105 and the CU 108 may vary depending on the implementation.

[0031] Cloud computing systems may also be used to provide the CU 108 and / or DU 105. A CU provided by a cloud computing system may be referred to as a virtualized CU (vCU). In addition to the vCU, there may also be a virtualized DU (vDU) provided by a cloud computing system. Furthermore, there may also be a combination, where the DU may be implemented on so-called bare metal solutions, for example application-specific integrated circuit (ASIC) or customer-specific standard product (CSSP) system-on-a-chip (SoC).

[0032] Edge cloud may be brought into the radio access network by utilizing network function virtualization (NFV) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a computing system operationally coupled to a remote radio head (RRH) or a radio unit (RU) 103 of an access node 104. It is also possible that access node operations may be performed on a distributed computing system or a cloud computing system located at the access node 104. Application of cloud RAN architecture enables RAN real-time functions being carried out at the radio access network (e.g., in a DU 105), and non-real-time functions being carried out in a centralized manner (e.g., in a CU 108).

[0033] 5G (or new radio, NR) wireless communication networks may support multiple hierarchies, where multi-access edge computing (MEC) servers may be placed between the core network 110 and the access node 104. It should be appreciated that MEC may be applied in LTE wireless communication networks as well.

[0034] A 5G wireless communication network (“5G network”) may also comprise a nonterrestrial communication network, such as a satellite communication network, to enhance or complement the coverage of the 5G radio access network. For example, satellite communication may support the transfer of data between the 5G radio access network and the core network 110, enabling more extensive networkcoverage. Possible use cases may include: providing service continuity for machine-to-machine (M2M) or Internet of Things (loT) devices or for passengers on board of vehicles, or ensuring service availability for critical communications, and future railway, maritime, or aeronautical communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, or low earth orbit (LEO) satellite systems, such as mega-constellations (i.e., systems in which hundreds of (nano)satellites are deployed). Alternatively, the satellites may be an airborne devices, such as an unmanned aerial vehicle (UAV), or a high-altitude platform system (HAPS). A given satellite 106 may provide communication services on Earth via one or more satellite beams. The one or more satellite beams create one or more cells over a given service area that may be bounded by the field of view of the satellite 106.

[0035] It is obvious for a person skilled in the art that the access node 104 depicted in FIG. 1A is just an example of a part of a radio access network, and in practice the radio access network may comprise a plurality of access nodes 104, the UEs 100, 102 may have access to a plurality of radio cells, and the radio access network may also comprise other apparatuses, such as physical layer relay access nodes or other entities. At least one of the access nodes may be a Home eNodeB or a Home gNodeB. A Home gNodeB or a Home eNodeB is a type of access node that may be used to provide indoor coverage inside a home, office, or other indoor environment.

[0036] Additionally, in a geographical area of a radio access network, a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which may be large cells having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The access node(s) 104 of FIG. 1A may provide any kind of these cells. A cellular radio network may be implemented as a multilayer access networks including several kinds of radio cells. In multilayer access networks, one access node may provide one kind of a radio cell or radio cells, and thus a plurality of access nodes may be needed to provide such a multilayer access network.

[0037] For fulfilling the need for improving performance of radio access networks, the concept of “plug-and-play” access nodes may be introduced. A radio access network, which may be able to use “plug-and-play” access nodes, may include, in addition to Home eNodeBs or Home gNodeBs, a Home Node B gateway (HNB-GW) (not shown in FIG. 1 A). An HNB-GW, which may be installed within an operator’s radio access network, may aggregate traffic from a large number of Home eNodeBs or Home gNodeBs back to a core network 110 of the operator.

[0038] 6G wireless communication networks are expected to adopt flexible decentralized and / or distributed computing systems and 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 may include intelligent connected management and control functions, programmability,integrated sensing and communication, reduction of energy footprint, trustworthy infrastructure, scalability and affordability. In addition to these, 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.

[0039] FIG. 1 B illustrates an example of a system, to which some example embodiments may be applied. FIG. 1B may be understood to depict a part of the wireless communication network of FIG. 1 A, but with greater accuracy with respect to a mobility scenario.

[0040] The system comprises at least a UE 100 and a plurality of access nodes 104, 104B, 104C, 104D controlling a plurality of cells 121, 122, 123, 124. Herein the term “cell” refers to a radio cell. Although four cells 121, 122, 123, 124 and four access nodes 104, 104B, 104C, 104D are shown in FIG. 1B, it should be noted that the number of cells and access nodes may also be higher or lower than four.

[0041] Moreover, in FIG. 1B, each of the cells is managed by a separate access node. However, it should be noted that one access node (e.g., 104, 104B, 104C, or 104D) may manage or control one or more cells 121, 122, 123, 124.

[0042] Referring to FIG. 1B, during a cell change (or handover), the connection of the UE 100 is transferred from the current serving cell (e.g., source cell) 121 controlled by a source access node 104 to a target cell 122 controlled by a target access node 104B, while preserving the ongoing voice call or data session.

[0043] The cell change procedure may be initiated by the network (e.g., the source access node 104), when certain pre-defined conditions are met, such as when the signal quality of the current serving cell 121 falls below a specified threshold, or when the signal quality of the neighboring cell 122 becomes better than that of the current serving cell 121 by a pre-defined offset. The decision to perform a cell change may be based on various factors, including radio measurements such as reference signal received power (RSRP) and / or reference signal received quality (RSRQ), network load, UE mobility, and network configuration parameters.

[0044] Upon initiation of the cell change procedure, the network (e.g., the source access node 104) may transmit a configuration message to the UE 100. This configuration message may include information about the target cell 122 and any needed configuration parameters. The UE 100 may then establish a connection with the target access node 104B controlling the target cell 122, synchronize its timing and frequency, and exchange control information to confirm the successful completion of the cell change. Once the cell change is completed, the UE 100 releases its connection with the previous serving cell 121, and the communication continues through the new serving cell 122.

[0045] The handover may be an intra-radio-access-technology (intra-RAT) handover or an interradio-access-technology (inter-RAT) handover. The cell change may also be an intra-frequency cell change or an inter-frequency cell change.

[0046] An intra-RAT handover means that the source cell 121 and the target cell 122 are based on the same radio access technology. For example, in an intra-NR handover, both the source access node 104 and the target access node 104B may be gNBs (i.e., NR base stations).

[0047] An inter-RAT handover means that the source cell 121 and the target cell 122 are based on different radio access technologies. For example, in an inter-RAT handover, the source access node 104 may be an eNB or ng-eNB (i.e., 4G base station), and the target access node 104B may be a gNB (i.e., NR base station), or vice versa.

[0048] There are various types of handover procedures. For example, a conditional handover (CHO) may be defined as a handover that is executed by the UE 100, when one or more handover execution conditions are met. In other words, the UE 100 receives (e.g., from the source access node 104) a configuration message with a CHO configuration indicating one or more handover execution conditions, but the UE 100 does not execute the handover until the one or more handover execution conditions are met. The UE 100 may start evaluating the one or more handover execution conditions upon receiving the CHO configuration, and stop evaluating the one or more handover execution conditions once a handover is executed.

[0049] An advantage of CHO is that it improves the mobility robustness compared to legacy handover by reducing the number of radio link failures and handover failures. This is achieved by de-coupling the handover execution phase from the preparation phase, thus enabling the UE 100 to receive the configuration message early, when the radio link of the source cell 121 is still sufficient, and executing the handover later when the radio link of the target cell 122 is strong enough.

[0050] The CHO configuration may be included in an RRC reconfiguration message, for example. The CHO configuration comprises the configuration of CHO candidate cell(s) 122, 123, 124 generated by the candidate target access node(s) 104B, 104C, 104D, and the one or more handover execution conditions generated by the source access node 104. The one or more handover execution conditions may comprise, for example CHO event A3 and / or CHO event A5. One or more reference signal types may be supported and one or more trigger quantities may be configured for the evaluation of the CHO execution condition of a given candidate cell 122, 123, 124. The one or more trigger quantities may comprise, for example, reference signal received power (RSRP), reference signal received quality (RSRQ), and / or signal-to-interference-plus-noise ratio (SINR).

[0051] CHO event A3 means that a trigger quantity (e.g., RSRP, RSRQ, and / or SINR) of a CHO candidate cell 122 indicated in the CHO configuration exceeds the trigger quantity (e.g., RSRP, RSRQ,and / or SI NR) of the source cell 121 by an offset for a certain time-to-trigger (TTT) period.

[0052] CHO event A5 means that the trigger quantity of the source cell 121 becomes lower than a first threshold, and the trigger quantity of a CHO candidate cell 122 indicated in the CHO configuration exceeds a second threshold for a certain TTT period.

[0053] CHO may also be supported for the integrated access and backhaul (IAB) mobile terminated (MT) in context of intra- and inter-donor IAB node migration and backhaul radio link failure recovery.

[0054] L1 / L2 triggered mobility (LTM) was introduced in NR Release 18. LTM cell switch is a procedure in which an access node 104 (e.g., gNB) receives L3 or L1 measurement report(s) from a UE 100, and on their basis the access node 104 changes the UE’s serving cell by a cell switch command signalled via a MAC control element (CE), for example. The cell switch command indicates an LTM candidate configuration that the access node 104 previously prepared and provided to the UE 100 through RRC signalling. Then the UE 100 switches to the target configuration according to the cell switch command. The LTM cell switch procedure can be used to reduce the mobility latency.

[0055] The original idea of LTM was to use L1 measurement reporting and trigger cell change via a MAC CE. However, L3 measurement reporting using beam level information has been allowed to be used (at least for frequency range 1) as a source of information for the network in deciding which cell to trigger for LTM and whether to trigger early UL / DL synchronization.

[0056] It is expected that a mechanism like Release 18 LTM and / or Release 19 LTM will be available in 6G, as it seems attractive to move the mobility triggering to lower protocol stack layers (i.e., faster processing, mobility with reduced delay, etc.) and enable early UL / DL synchronization (i.e., no need to perform the synchronization at the time of the actual cell change).

[0057] The UE 100 may perform measurements of the radio signals that the UE 100 receives from one or more cells 121 , 122, 123 (or from the corresponding access nodes 104, 104B, 104C), and the UE 100 may report these measurements to the access node 104 of the serving cell 121. For example, these measurements may be based on at least one of the following metrics: reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-interference-plus-noise ratio (SI NR), or received signal strength indicator (RSSI).

[0058] For example, in NR, the UE measurements and reporting may be used for beam management, carrier aggregation and / or mobility purposes (e.g., handovers). The UE measurements may be performed and reported at Layer 1 (i.e., physical layer) and / or Layer 3 (i.e., RRC layer). The measurements may be based on a synchronization signal block (SSB) or, if configured in a measurement configuration (e.g., CSI-MeasConfig), also based on a channel state information reference signal (CSI-RS).

[0059] L1 measurements refer to physical layer measurements. L1 measurements are beam-level measurements that were originally introduced for the purpose of beam management (BM) and for the serving cell only. Later L1 measurement support for L1 RSRP for inter-cell BM was introduced (enabling measurements and reporting for a non-serving cell). Additionally, L1 measurements and reporting have been introduced for cell change or cell switch, such as LTM. L1 RSRP measurements may be reported by the UE 100 in channel state information (CSI) based on CSI-ReportConfig. L1 measurements and reporting may be configured for the serving cell for beam management purposes and for neighboring cells 122, 123 for example for lower-layer mobility purposes (e.g., LTM).

[0060] L1 measurement reporting may be done as CSI reporting on L1. L1 measurement reporting for serving and neighboring cells may be configured as periodic, semi-persistent, or aperiodic. Furthermore, In NR Release 19, event-triggered L1 reporting for beam management and LTM purposes may be defined. The periodic reporting means that the UE transmits the reports with a configured periodicity. The semi-persistent reporting means that the reporting is either activated by the network by a MAC CE for the physical uplink control channel (PUCCH), or triggered by the network by downlink control information (DCI) for the physical uplink shared channel (PUSCH). The aperiodic reporting means that the reporting is triggered by the network by a DCI for one cell at a time on PUSCH.

[0061] L3 measurements involve the radio resource control (RRC) layer, which manages higher-level tasks such as configuring measurement parameters, filtering L1 measurements, and / or making decisions based on long-term channel conditions. L3 measurements may be cell-level or synchronization signal block (SSB) level measurements. In frequency range one (FR1), SSB-level measurements may, in some cases, be generated from the L1 measurements by applying L3 filtering. Cell-level measurements may be derived from the L1 measurements using certain rules. L3 RSRP measurements may be reported in an RRC measurement report in the MeasResults information element.

[0062] L3 measurement reporting may be done on the RRC level. L3 measurement reporting may be configured as periodic, event-triggered, or event-triggered periodic. The periodic reporting means that the UE transmits the reports with a configured periodicity. The event-triggered reporting means that the UE transmits the report when a configured condition forevent-triggered reporting is fulfilled (multiple different events may be supported for mobility purposes). The event-triggered periodic reporting means that the UE starts periodic reporting once a configured condition for event-triggered periodic reporting is fulfilled.

[0063] Some example embodiments provide a method for L1 and L3 measurement result storing and reporting (e.g., in a mobility scenario). Some example embodiments aim at resolving the inconsistency if a subset of UEs in a cell operate using L1 measurements while the remainder rely on L3 measurements. Another possibility is that a single UE is configured with L1 measurements and reporting for a subset of candidate cells, while L3 measurements are used for other candidate cells. Such configurations are expected to be possible by 3GPP specification.

[0064] If a single UE can be configured with L1 measurements and reporting for a subset of candidate LTM cells, while L3 measurement reporting is configured for the other candidate LTM cells, it may have an impact on the definition of cell borders (i.e., the triggering regions for handovers and measurement reporting), etc. This is because L3 measurement results are effectively a filtered version of L1 measurements, with a certain delay (see FIG. 2). For example, one UE can trigger the report based on L1 measurement result(s), while another UE may trigger the report based on an L3 measurement reporting threshold (see the time ti, t2 in FIG. 3).

[0065] The issue may be even more severe when conditional LTM (CLTM) is introduced. In case of the CLTM, a single UE might have an L1 condition for a subset of candidate LTM cells, and an L3 condition for remaining candidate LTM cells. Another possible scenario is that a subset of UEs in the cell is configured with L1 measurements and execution condition, while another subset of UEs is configured with L3 measurements and execution condition. In this case, the cell change may happen at an unpredictable point in time and location (unpredictable in the sense that it may not be aligned between different UEs and between what the network expects and what the UE actually does).

[0066] In other words, if the cell comprises a mixture of UEs supporting different types of measurements (L1, L3), then the measurement reports may not be directly comparable and cell borders may be misaligned.

[0067] FIG. 2 illustrates a comparison between L1 measurements 201 (moderate smoothing) and L3 measurements 202 (more smooth). In FIG. 2, it can be seen that the L3 measurements 202 undergo additional filtering compared to the L1 measurements 201, which also incurs a delay.

[0068] FIG. 3 illustrates an example embodiment for L1 and L3 measurement sample reporting in time. For optimization of the mobility between a cell pair, the following logging can be considered:

[0069] When the reporting for LTM is triggered based on L1 measurements for a first UE 100 (at time ti in FIG. 3), the first UE 100 may store additionally the latest L3 measurement (and may subsequently report it, e.g., as a part of a self-organizing network framework).

[0070] When the reporting for LTM is triggered based on L3 measurements for a second UE 102 (at time to in FIG. 3), the second UE 102 may store additionally the latest L1 measurement (and may subsequently report it, e.g., as a part of a self-organizing network framework).

[0071] The additionally latest stored L3 measurement (by the first UE 100 in the scenario above) or L1 measurement (by the second UE 102 in the scenario above) may be also reported by the respective UE when it completes the cell change and / or transmits the first message to the target cell (e.g., in Msg5). For example, this may be applicable in case of CLTM (where no measurement reporting occurs to the source cell prior to the cell change execution). For example, the first message may be or be included in a Msg5, anRRC reconfiguration complete message, or any subsequent message indicating measurement result(s) to be reported.

[0072] For example, in network-triggered LTM, some example embodiments help the network to gain additional information when it has both types of measurement results available. Based on this information, the network can correctly determine the point in time when the LTM cell switch command should be sent - either for this LTM cell switch execution and this UE, or for a long-term optimization of this cell border where measurement reporting or cell switching triggering based on either L1 or L3 measurements can happen.

[0073] Some example embodiments are described below using principles and terminology of 5G radio access technology without limiting the example embodiments to 5G radio access technology, however. For example, some example embodiments may also be applicable in 6G and beyond.

[0074] FIG. 4 illustrates a signal flow diagram according to an example embodiment.

[0075] In this example embodiment, at time ti (see FIG. 3), the L1 -based condition for measurement reporting is met. The UE 100 additionally stores the corresponding L3 measurement result. The L3 measurement result that the UE 100 stores may be the latest L3 measurement result available when the condition is met (which may be taken either at time ti or before this if the measurements are not overlapping), or the latest L3 measurement result available when transmitting the measurement report (if there is time for the UE to perform and obtain another measurement result between triggering and transmitting the measurement report). This stored L3 measurement result can be included together with the L1 measurement result in the measurement report transmitted at 406, which is triggered based on the L1 measurement. Alternatively, the L3 measurement result can be provided directly to the target cell (denoted as the second cell 122 in FIG. 4), when the cell change is completed at 409.

[0076] Referring to FIG. 4, at 401 , a first network device 104 associated with a first cell 121 may generate and transmit, to the UE 100, an RRC reconfiguration message comprising a measurement configuration for L1 measurements. For example, the measurement configuration may be comprised in an LTM candidate cell configuration. The LTM candidate cell configuration may include the UE configuration to be used in the target cell after a cell change. The UE configuration may include parameters and settings of the UE 100. For example, the UE configuration may include at least one of: UE identifier(s), configuration of radio bearers, or dedicated scheduling resources. The UE configuration may indicate how to configure the protocol stack of the UE to be used in the target cell.

[0077] The first network device 104 may refer to an access node (e.g., a gNB) controlling the first cell 121. The first cell 121 may refer to the current serving cell of the UE 100 (i.e., the source cell of the cell change).

[0078] The measurement configuration indicates at least one condition (or event) for reportingat least one L1 measurement result. The at least one L1 measurement result may also be referred to as at least one measurement result of a first measurement type.

[0079] For example, the at least one condition for reporting the at least one L1 measurement result may comprise at least one of: event LTM2, event LTM3, event LTM4, or event LTM5. These LTM events are based on beam-specific quality of the first cell (e.g., serving cell or source cell) 121 and / or one or more candidate cells 122, 123, 124.

[0080] Event LTM2 means that the beam of the first cell 121 becomes worse than an absolute threshold.

[0081] Event LTM3 means that the beam of a second cell (e.g., candidate cell) 122 becomes better than the beam of the first cell 121 by a certain offset.

[0082] Event LTM4 means that the beam of the candidate cell 122 becomes better than an absolute threshold.

[0083] Event LTM5 means that the beam of the first cell 121 becomes worse than an absolute threshold, and the beam of the second cell 122 becomes better than another absolute threshold.

[0084] The measurement configuration may comprise at least one of: a measurement event configuration or a measurement reporting configuration.

[0085] The measurement event configuration specifies the conditions under which the UE 100 should report L1 measurement results to the first network device 104 (via the first cell 121). The measurement event configuration may comprise one or more thresholds and / or events (e.g., a neighboring cell becoming stronger than the first cell 121) that trigger the reporting of the L1 measurement results.

[0086] The measurement reporting configuration may define how and when the UE 100 should report the L1 measurement results to the first network device 104 (via first cell 121). For example, the measurement reporting configuration may indicate at least one of: a reporting mode (e.g., event-triggered or periodic), a reporting interval, and / or the type of information to be included in the measurement reports (e.g., signal strength and / or signal quality).

[0087] The measurement reporting configuration may further indicate one or more carriers associated with the one or more candidate cells that the UE 100 should measure and report.

[0088] The measurement configuration may further comprise an indication indicating whether to report at least one L3 measurement result corresponding to the at least one L1 measurement result. Alternatively, the first network device 104 may transmit the indication to the UE 100 separately from the measurement configuration (e.g., at 407). If the indication indicates that the at least one L3 measurement result is to be reported, then the UE 100 may report the at least one L3 measurement result to the first network device 104 (e.g., at 406). If the indication indicates that the at least one L3 measurement result is not to be reported, or if no indication is received from the first network device 104 for reporting the at leastone L3 measurement result, then the UE 100 may not report the at least one L3 measurement result to the first network device 104 (e.g., at 406).

[0089] In other words, the network may indicate whether it also wants the at least one L3 measurement result to be reported. The UE may also store the L3 measurement results and report these afterwards (e.g., as an entire set of measurement results, not as a single result), when it is configured or indicated by the network to provide such assistance information.

[0090] The at least one L3 measurement result may also be referred to as at least one measurement result of a second measurement type.

[0091] At 402, the UE 100 applies the measurement configuration. For example, the UE 100 may perform the at least one L1 measurement based on the measurement configuration.

[0092] At 403, the UE 100 transmits, to the first network device 104 via the first cell 121, an RRC reconfiguration complete message to indicate that the RRC reconfiguration was successfully completed.

[0093] At 404, the UE 100 determines that the at least one condition is fulfilled for reporting the at least one L1 measurement result. The UE 100 may have obtained and stored the at least one L1 measurement result prior to determining that the at least one condition is fulfilled.

[0094] At 405, based on or in response to determining that the at least one condition is fulfilled, the UE 100 stores at least one L3 measurement result corresponding to (or related to) the at least one L1 measurement result. For example, the UE 100 may store the at least one L3 measurement result in an internal memory of the UE 100.

[0095] The UE 100 may have obtained the at least one L3 measurement result prior to determining that the at least one condition is fulfilled. Alternatively, the UE 100 may obtain the at least one L3 measurement result by performing at least one L3 measurement after determining that the condition is fulfilled and before reporting the at least one L1 measurement result.

[0096] The at least one L1 measurement result and the at least one L3 measurement result may be obtained by measuring at least one signal metric such as RSRP and / or RSRQ from at least one of: a reference signal transmitted on the first cell 121 (from the first network device 104), and / or a reference signal transmitted on the second cell 122 (from a second network device 104B). The second cell 122 may also be referred to as a candidate cell or a target cell.

[0097] The at least one L1 measurement result and the at least one L3 measurement result may be based on a same reference signal type, such as a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS). In other words, the measurement result(s) reported by the UE 100 may be of the same reference signal type as the measurement that triggered the measurement report. For example, if an SSB-based L1 reporting condition is used for the measurement reporting evaluation, andthe UE 100 is also configured with SSB-based and CSI-RS-based L3 measurement, the UE 100 may report the SSB-based L3 measurement.

[0098] If the reference signal type for L1 and L3 measurement is different, and for example CSI-RS based L1 measurement triggers a report and the UE 100 is not configured to perform CSI-RS based L3 measurement for the same cell, then the UE 100 may not report the L3 measurement, or the UE 100 may report the L3 measurement of the different reference signal type (e.g., CSI-RS based L3 measurement).

[0099] At 406, the UE 100 generates and transmits a measurement report to the first network device 104 via the first cell 121. The measurement report comprises the at least one L1 measurement result. The UE 100 may also report the at least one L3 measurement result to the first network device 104 via the first cell 121. For example, the at least one L3 measurement result may be transmitted in the measurement report together with the at least one L1 measurement result, or transmitted in a separate message from the measurement report including the at least one L1 measurement result (e.g., if the first network device 104 later indicates the UE 100 to report the at least one L3 measurement result).

[0100] The at least one L3 measurement result may comprise a latest L3 measurement result that is available when determining that the at least one condition is fulfilled, or when reporting the at least one L1 measurement result.

[0101] At 407, based on the measurement report, the first network device 104 transmits (via the first cell 121), to the UE 100, a handover command or a cell switch command for switching the UE 100 from the first cell 121 to the second cell 122. For example, the handover command or cell switch command may be transmitted in a MAC CE. In this description, the terms “cell change” and “cell switch” may be used interchangeably.

[0102] At 408, when the cell change is triggered, the first network device 104 (first cell 121) may start to forward data (e.g., unsent or unacknowledged data related to this UE 100) to the second network device 104B associated with the second cell 122.

[0103] The second network device 104B may refer to another access node (e.g., another gNB) controlling the second cell 122. Alternatively, the first cell 121 and the second cell 122 may be controlled by the same access node.

[0104] Herein the terms “first network device” and “second network device” are used to distinguish the network devices, and they do not necessarily refer to a specific order or specific identifiers of the network devices. Similarly, the terms “first cell” and “second cell” are used to distinguish the cells, and they do not necessarily refer to a specific order or specific identifiers of the cells.

[0105] At 409, based on the handover command or cell switch command, the UE 100 executes a cell change for switching from the first cell 121 to the second cell 122.

[0106] During or after the cell change procedure, the UE 100 may report the at least one L3measurement result to the second network device 104B (second cell 122). In other words, the UE 100 may report the at least one L3 measurement result to the second network device 104B based on or in response to completing the cell change.

[0107] At 410, the first network device 104 (first cell 121) may adjust one or more parameters related to triggering cell changes in the first cell 121 controlled by the first network device 104, wherein the adjustment is based at least partly on the at least one L1 measurement result and / or the at least one L3 measurement result. For example, based on the received information, the first network device 104 (first cell 121) may change the thresholds that trigger the handover so that the handover from the first cell 121 is performed at the same time (or same location) and the cell border is consistent. The cell border may be defined by the radio signal level / quality. If the measurements are not unified (e.g., L1 and L3), then in the same geolocation one UE (using L1) will find the current cell to be still sufficiently good while the other UE (using L3) might already trigger the cell change.

[0108] It should be noted that the adjustment may not be performed instantaneously based on a single UE’s measurement results, but the aim may instead be for long-term parameter adjustment. Thus, the first network device 104 may be learning based on multiple UEs' measurement reports and optimize the settings for the entire cell (first cell) 121. In other words, adjustment may be performed as part of a selforganizing network (SON) framework.

[0109] FIG. 5 illustrates a signal flow diagram according to an example embodiment.

[0110] In this example embodiment, at time to (see FIG. 3), the L3-based condition for measurement reporting is met. The UE 102 additionally stores the corresponding L1 measurement result, where the L1 measurement result may be the latest measurement before triggering or transmitting the report, directly overlapping or not overlapping with the L3 measurement that triggered the measurement report. The L1 measurement result may be reported at 506, or at 509 when the cell change procedure is completed.

[0111] Referring to FIG. 5, at 501, a first network device 104 associated with a first cell 121 may generate and transmit, to the UE 102, an RRC reconfiguration message comprising a measurement configuration for L3 measurements. For example, the measurement configuration may be comprised in an LTM candidate cell configuration. The LTM candidate cell configuration may include the UE configuration to be used in the target cell after a cell change. The UE configuration may include parameters and settings of the UE 102. For example, the UE configuration may include at least one of: UE identifier(s), configuration of radio bearers, or dedicated scheduling resources. The UE configuration may indicate how to configure the protocol stack of the UE to be used in the target cell.

[0112] The first network device 104 may refer to an access node (e.g., a gNB) controlling the first cell 121. The first cell 121 may refer to the current serving cell of the UE 102 (i.e., the source cell of the cell change).

[0113] The measurement configuration indicates at least one condition (or event) for reporting at least one L3 measurement result. The at least one L3 measurement result may also be referred to as at least one measurement result of a first measurement type.

[0114] For example, the at least one condition for reporting the at least one L3 measurement result may comprise at least one of: event A1 , event A2, event A3, event A4, event A5, or event A6.

[0115] Event A1 means that the signal strength or quality of the first cell (serving cell) 121 becomes better than a threshold.

[0116] Event A2 means that the signal strength or quality of the first cell (serving cell) 121 becomes worse than a threshold.

[0117] Event A3 means that the signal strength or quality of a neighbor cell (e.g., a second cell 122) becomes better than the signal strength or quality of the special cell (e.g., the first cell 121) by a certain offset.

[0118] Event A4 means that the signal strength or quality of a neighbor cell (e.g., the second cell 122) becomes better than a threshold.

[0119] Event A5 means that the signal strength or quality of the special cell (e.g., the first cell 121) becomes worse than a first threshold, and the signal strength or quality of a neighbor cell (e.g., the second cell 122) becomes better than a second threshold.

[0120] Event A6 means that the signal strength or quality of a neighbor cell (e.g., the second cell 122) becomes better than the signal strength or quality of a secondary cell (SCell) by a certain offset.

[0121] The measurement configuration may comprise at least one of: a measurement event configuration or a measurement reporting configuration.

[0122] The measurement event configuration specifies the conditions under which the UE 102 should report L3 measurement results to the first network device 104 (first cell 121 ). The measurement event configuration may comprise one or more thresholds and / or events (e.g., a neighboring cell becoming stronger than the serving cell 121) that trigger the reporting of the L3 measurement results.

[0123] The measurement reporting configuration may define how and when the UE 102 should report the L3 measurement results to the first network device 104 (first cell 121). For example, the measurement reporting configuration may indicate at least one of: a reporting mode (e.g., event-triggered or periodic), a reporting interval, and / or the type of information to be included in the measurement reports (e.g., signal strength and / or signal quality).

[0124] The measurement reporting configuration may further indicate one or more carriers associated with the one or more candidate cells that the UE 102 should measure and report.

[0125] The measurement configuration may further comprise an indication indicating whether to report at least one L1 measurement result corresponding to the at least one L3 measurement result.Alternatively, the first network device 104 may transmit the indication to the UE 102 separately from the measurement configuration (e.g., at 507). If the indication indicates that the at least one L1 measurement result is to be reported, then the UE 102 may report the at least one L1 measurement result to the first network device 104 (e.g., at 506). If the indication indicates that the at least one L1 measurement result is not to be reported, or if no indication is received from the first network device 104 for reporting the at least one L1 measurement result, then the UE 102 may not report the at least one L1 measurement result to the first network device 104 (e.g., at 506).

[0126] In other words, the network may indicate whether it also wants the at least one L1 measurement result to be reported. The UE may also store the L1 measurement results and report these afterwards (e.g., as an entire set of measurement results, not as a single result), when it is configured or indicated by the network to provide such assistance information.

[0127] The at least one L1 measurement result may also be referred to as at least one measurement result of a second measurement type.

[0128] At 502, the UE 102 applies the measurement configuration. For example, the UE 102 may perform the at least one L3 measurement based on the measurement configuration.

[0129] At 503, the UE 102 transmits, to the first network device 104 via the first cell 121, an RRC reconfiguration complete message to indicate that the RRC reconfiguration was successfully completed.

[0130] At 504, the UE 102 determines that the at least one condition is fulfilled for reporting the at least one L3 measurement result. The UE 102 may have obtained and stored the at least one L3 measurement result prior to determining that the at least one condition is fulfilled.

[0131] At 505, based on or in response to determining that the at least one condition is fulfilled, the UE 102 stores at least one L1 measurement result corresponding to (or related to) the at least one L3 measurement result. For example, the UE 102 may store the at least one L1 measurement result in an internal memory of the UE 102.

[0132] The UE 102 may have obtained the at least one L1 measurement result prior to determining that the at least one condition is fulfilled. Alternatively, the UE 102 may obtain the at least one L1 measurement result by performing at least one L3 measurement after determining that the condition is fulfilled and before reporting the at least one L3 measurement result.

[0133] The at least one L1 measurement result and the at least one L3 measurement result may be obtained by measuring at least one signal metric such as RSRP and / or RSRQ from at least one of: a reference signal transmitted on the first cell 121 (from the first network device 104), and / or a reference signal transmitted on the second cell 122 (from a second network device 104). The second cell 122 may also be referred to as a candidate cell or a target cell.

[0134] The at least one L1 measurement result and the at least one L3 measurement result may be based on a same reference signal type, such as a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS). In other words, the measurement result(s) reported by the UE 102 may be of the same reference signal type as the measurement that triggered the measurement report. For example, if an SSB-based L3 reporting condition is used for the measurement reporting evaluation, and the UE 102 is also configured with SSB-based and CSI-RS-based L1 measurement, the UE 102 may report the SSB-based L1 measurement.

[0135] If the reference signal type for L1 and L3 measurement is different, and for example CSI-RS based L3 measurement triggers a report and the UE 102 is not configured to perform CSI-RS based L1 measurement for the same cell, then the UE 102 may not report the L1 measurement, or the UE 102 may report the L1 measurement of the different reference signal type (e.g., CSI-RS based L1 measurement).

[0136] At 506, the UE 102 transmits a measurement report to the first network device 104 via the first cell 121. The measurement report comprises the at least one L3 measurement result. The UE 102 may also report the at least one L1 measurement result to the first network device 104 via the first cell 121. For example, the at least one L3 measurement result may be transmitted in the measurement report together with the at least one L3 measurement result, or transmitted in a separate message from the measurement report including the at least one L1 measurement result (e.g., if the first network device 104 later indicates the UE 102 to report the at least one L1 measurement result).

[0137] The at least one L1 measurement result may comprise a latest L1 measurement result that is available when determining that the at least one condition is fulfilled, or when reporting the at least one L3 measurement result.

[0138] At 507, based on the measurement report, the first network device 104 transmits (via the first cell 121), to the UE 102, a handover command or a cell switch command for switching the UE 102 from the first cell 121 to a second cell 122. For example, the handover command or cell switch command may be transmitted in a MAC CE.

[0139] At 508, the first network device 104 (first cell 121) may start to forward data (e.g., unsent or unacknowledged data related to this UE 102) to the second network device 104B associated with the second cell 122.

[0140] The second network device 104B may refer to another access node (e.g., another gNB) controlling the second cell 122. Alternatively, the first cell 121 and the second cell 122 may be controlled by the same access node.

[0141] Herein the terms “first network device” and “second network device” are used to distinguish the network devices, and they do not necessarily refer to a specific order or specific identifiers of the network devices. Similarly, the terms “first cell” and “second cell” are used to distinguish the cells, andthey do not necessarily refer to a specific order or specific identifiers of the cells.

[0142] At 509, based on the handover command or cell switch command, the UE 102 executes a cell change for switching from the first cell 121 to the second cell 122.

[0143] During or after the cell change procedure, the UE 102 may report the at least one L1 measurement result to the second network device 104B (second cell 122). In other words, the UE 102 may report the at least one L1 measurement result to the second network device 104B based on or in response to completing the cell change.

[0144] At 510, the first network device 104 (first cell 121) may adjust one or more parameters related to triggering cell changes in the first cell 121 controlled by the first network device 104, wherein the adjustment is based at least partly on the at least one L1 measurement result and / or the at least one L3 measurement result. For example, based on the received information, the first network device 104 (first cell 121) may change the thresholds that trigger the handover so that the handover from the first cell 121 is performed at the same time (or same location) and the cell border is consistent.

[0145] It should be noted that the adjustment may not be performed instantaneously based on a single UE's measurement results, but the aim may instead be for long-term parameter adjustment. Thus, the first network device 104 may be learning based on multiple UEs' measurement reports and optimize the settings for the entire cell (first cell) 121. In other words, adjustment may be performed as part of a selforganizing network (SON) framework.

[0146] FIG. 6 illustrates a signal flow diagram according to an example embodiment for a conditional cell change. The conditional cell change may refer to, for example, a conditional LTM cell switch or any other type of conditional (e.g., UE-initiated) cell switch or handover.

[0147] In this example embodiment, at time ti (see FIG. 3), the L1 -based condition for conditional cell change (e.g., for CLTM) is met. The UE 100 additionally stores the corresponding L3 measurement result. The L3 measurement result that the UE 100 stores may be the latest L3 measurement result available when the condition is met (which may be taken either at time ti or before this if the measurements are not overlapping), or the latest L3 measurement result available when triggering the conditional cell change. In the case of conditional cell change (e.g., CLTM), the current framework does not support reporting the measurement that triggers the cell change (i.e. , the L1 measurement in this case). However, in this example embodiment, the UE may report both the triggering result (e.g. L1) and the other measurement type (e.g., L3) and possibly also another reference signal, if measured, after the cell change completion (i.e., directly to the new serving cell 122).

[0148] Referring to FIG. 6, at 601 , a first network device 104 associated with a first cell 121 may generate and transmit, to the UE 100, an RRC reconfiguration message comprising a measurement configuration for L1 measurements. For example, the measurement configuration may be comprised in aCLTM candidate cell configuration. The CLTM candidate cell configuration may include the UE configuration to be used in the target cell after a cell change. The UE configuration may include parameters and settings of the UE 100. For example, the UE configuration may include at least one of: UE identifier(s), configuration of radio bearers, or dedicated scheduling resources. The UE configuration may indicate how to configure the protocol stack of the UE to be used in the target cell.

[0149] The first network device 104 may refer to an access node (e.g., a gNB) controlling the first cell 121. The first cell 121 may refer to the current serving cell of the UE 100 (i.e., the source cell of the cell change).

[0150] The measurement configuration indicates at least one condition (or event) for triggering a conditional cell change (e.g., CLTM). The at least one condition may be based on at least one L1 measurement result. The completion of the cell change may trigger reporting of the at least one L1 measurement result. The at least one L1 measurement result may also be referred to as at least one measurement result of a first measurement type.

[0151] For example, the at least one condition for triggering the conditional cell change may comprise at least one of the CHO event A3 or the CHO event A5 described above. As another example, the at least one condition for triggering the conditional cell change may comprise at least one of the LTM2, LTM3, LTM4 or LTM5 event described above, with the difference that once such condition is met, the UE executes the cell change (instead of triggering the measurement reporting).

[0152] The measurement configuration may comprise at least one of: a measurement event configuration or a measurement reporting configuration.

[0153] The measurement event configuration specifies the conditions under which the UE 100 should report L1 measurement results to the first network device 104 (first cell 121 ). The measurement event configuration may comprise one or more thresholds and / or events (e.g., triggering the conditional cell change) that trigger the reporting of the L1 measurement results.

[0154] The measurement reporting configuration may define how and when the UE 100 should report the L1 measurement results to the first network device 104 (first cell 121). For example, the measurement reporting configuration may indicate at least one of: a reporting mode (e.g., event-triggered or periodic), a reporting interval, and / or the type of information to be included in the measurement reports (e.g., signal strength and / or signal quality).

[0155] The measurement reporting configuration may further indicate one or more carriers associated with the one or more candidate cells for the conditional cell change that the UE 100 should measure and report.

[0156] At 602, the UE 100 applies the measurement configuration. For example, the UE 100 may perform the at least one L1 measurement based on the measurement configuration.

[0157] At 603, the UE 100 transmits, to the first network device 104 via the first cell 121, an RRC reconfiguration complete message to indicate that the RRC reconfiguration was successfully completed.

[0158] At 604, based on the at least one L1 measurement result, the UE 100 determines that the at least one condition is fulfilled for triggering the conditional cell change. The UE 100 may have obtained and stored the at least one L1 measurement result prior to determining that the at least one condition is fulfilled.

[0159] At 605, based on or in response to determining that the at least one condition is fulfilled, the UE 100 stores at least one L3 measurement result corresponding to (or related to) the at least one L1 measurement result. For example, the UE 100 may store the at least one L3 measurement result in an internal memory of the UE 100. The at least one L3 measurement result may also be referred to as at least one measurement result of a second measurement type.

[0160] The UE 100 may have obtained the at least one L3 measurement result prior to determining that the at least one condition is fulfilled. Alternatively, the UE 100 may obtain the at least one L3 measurement result by performing at least one L3 measurement after determining that the condition is fulfilled and before executing the conditional cell change.

[0161] The at least one L1 measurement result and the at least one L3 measurement result may be obtained by measuring at least one signal metric such as RSRP and / or RSRQ from at least one of: a reference signal transmitted on the first cell 121 (from the first network device 104), and / or a reference signal transmitted on a second cell 122 (from a second network device 104B). The second cell 122 may also be referred to as a candidate cell or a target cell.

[0162] The at least one L1 measurement result and the at least one L3 measurement result may be based on a same reference signal type, such as a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS). In other words, the measurement result(s) reported by the UE 100 may be of the same reference signal type as the measurement that triggered the measurement report. For example, if an SSB-based L1 condition is used for evaluating the at least one condition for triggering the conditional cell change, and the UE 100 is also configured with SSB-based and CSI-RS-based L3 measurement, the UE 100 may report the SSB-based L3 measurement.

[0163] If the reference signal type for L1 and L3 measurement is different, and for example CSI-RS based L1 measurement triggers the conditional cell change and the UE 100 is not configured to perform CSI-RS based L3 measurement for the same cell, then the UE 100 may not report the L3 measurement, or the UE 100 may report the L3 measurement of the different reference signal type (e.g., CSI-RS based L3 measurement).

[0164] At 606, the first network device 104 (first cell 121) may start to forward data (e.g., unsentor unacknowledged data related to this UE 100) to the second network device 104B associated with the second cell 122.

[0165] The second network device 104B may refer to another access node (e.g., another gNB) controlling the second cell 122. Alternatively, the first cell 121 and the second cell 122 may be controlled by the same access node.

[0166] Herein the terms “first network device” and “second network device” are used to distinguish the network devices, and they do not necessarily refer to a specific order or specific identifiers of the network devices. Similarly, the terms “first cell” and “second cell” are used to distinguish the cells, and they do not necessarily refer to a specific order or specific identifiers of the cells.

[0167] At 607, based on or in response to determining that the at least one condition is fulfilled, the UE 100 executes the conditional cell change for switching the UE 100 from the first cell 121 to the second cell 122.

[0168] During or after the cell change, the UE 100 generates and transmits a measurement report to the second network device 104B via the second cell 122, wherein the measurement report comprises the at least one L1 measurement result and the at least one L3 measurement result. In other words, the UE 100 may report the at least one L1 measurement result and the at least one L3 measurement result to the second network device 104B based on or in response to completing the conditional cell change. For example, the measurement results may be reported in a Msg5, an RRC reconfiguration complete message, or any subsequent message indicating measurement result(s) to be reported.

[0169] For example, after the cell change is completed, the UE 100 may transmit a message (e.g., an RRC reconfiguration complete message) to the second network device 104B to indicate the availability of the at least one L1 measurement result and the at least one L3 measurement result, and the second network device 104B may then request or configure the UE 100 to report the measurement results. In this case, the UE 100 may report the measurement results based on the request or configuration.

[0170] The at least one L3 measurement result may comprise a latest L3 measurement result that is available when determining that the at least one condition is fulfilled, or when executing the conditional cell change.

[0171] At 608, the second network device 104B (second cell 122) may adjust one or more parameters related to triggering cell changes in the second cell 122 controlled by the second network device 104B, wherein the adjustment is based at least partly on the at least one L1 measurement result and the at least one L3 measurement result. For example, based on the received information, the second network device 104B (second cell 122) may change the thresholds that trigger the conditional cell change so that the cell change is performed at the same time (or same location) and the cell border is consistent.

[0172] It should be noted that the adjustment may not be performed instantaneously based on a single UE's measurement results, but the aim may instead be for long-term parameter adjustment. Thus, the second network device 104B may be learning based on multiple UEs' measurement reports and optimize the settings for the entire cell 122. In other words, adjustment may be performed as part of a self-organizing network (SON) framework.

[0173] FIG. 7 illustrates a signal flow diagram according to an example embodiment for a conditional cell change. The conditional cell change may refer to, for example, a conditional LTM cell switch or any other type of conditional (e.g., UE-initiated) cell switch or handover.

[0174] In this example embodiment, at time to (see FIG. 3), the L3-based condition for conditional cell change (e.g., for CLTM) is met. The UE 102 additionally stores the corresponding L1 measurement result. The L1 measurement result that the UE 102 stores may be the latest L1 measurement result available when the condition is met (which may be taken either at time to or before this if the measurements are not overlapping), or the latest L1 measurement result available when triggering the conditional cell change. In the case of conditional cell change (e.g., CLTM), the current framework does not support reporting the measurement that triggers the cell change (i.e., the L3 measurement in this case). However, in this example embodiment, the UE may report both the triggering result (e.g. L3) and the other measurement type (e.g., L1) and possibly also another reference signal, if measured, after the cell change completion (i.e., directly to the new serving cell 122).

[0175] Referring to FIG. 7, at 701, a first network device 104 associated with a first cell 121 may generate and transmit, to the UE 102, an RRC reconfiguration message comprising a measurement configuration for L1 measurements. For example, the measurement configuration may be comprised in a CLTM candidate cell configuration. The CLTM candidate cell configuration may include the UE configuration to be used in the target cell after a cell change. The UE configuration may include parameters and settings of the UE 102. For example, the UE configuration may include at least one of: UE identifier(s), configuration of radio bearers, or dedicated scheduling resources. The UE configuration may indicate how to configure the protocol stack of the UE to be used in the target cell.

[0176] The first network device 104 may refer to an access node (e.g., a gNB) controlling the first cell 121. The first cell 121 may refer to the current serving cell of the UE 102 (i.e., the source cell of the cell change).

[0177] The measurement configuration indicates at least one condition (or event) for triggering a conditional cell change (e.g., CLTM). The at least one condition may be based on at least one L3 measurement result. The completion of the cell change may trigger reporting of the at least one L3 measurement result. The at least one L3 measurement result may also be referred to as at least one measurement result of a first measurement type.

[0178] For example, the at least one condition for triggering the conditional cell change may comprise at least one of the CHO event A3 or the CHO event A5 described above. As another example, the at least one condition for triggering the conditional cell change may comprise at least one of the LTM2, LTM3, LTM4 or LTM5 event described above, with the difference that once such condition is met, the UE executes the cell change (instead of triggering the measurement reporting).

[0179] The measurement configuration may comprise at least one of: a measurement event configuration or a measurement reporting configuration.

[0180] The measurement event configuration specifies the conditions under which the UE 102 should report L3 measurement results to the first network device 104 (first cell 121 ). The measurement event configuration may comprise one or more thresholds and / or events (e.g., triggering the conditional cell change) that trigger the reporting of the L1 measurement results.

[0181] The measurement reporting configuration may define how and when the UE 102 should report the L3 measurement results. For example, the measurement reporting configuration may indicate at least one of: a reporting mode (e.g., event-triggered or periodic), a reporting interval, and / or the type of information to be included in the measurement reports (e.g., signal strength and / or signal quality).

[0182] The measurement reporting configuration may further indicate one or more carriers associated with the one or more candidate cells for the conditional cell change that the UE 102 should measure and report.

[0183] At 702, the UE 102 applies the measurement configuration. For example, the UE 102 may perform the at least one L3 measurement based on the measurement configuration.

[0184] At 703, the UE 102 transmits, to the first network device 104 via the first cell 121, an RRC reconfiguration complete message to indicate that the RRC reconfiguration was successfully completed.

[0185] At 704, based on the at least one L3 measurement result, the UE 102 determines that the at least one condition is fulfilled for triggering the conditional cell change. The UE 102 may have obtained and stored the at least one L3 measurement result prior to determining that the at least one condition is fulfilled.

[0186] At 705, based on or in response to determining that the at least one condition is fulfilled, the UE 102 stores at least one L1 measurement result corresponding to (or related to) the at least one L3 measurement result. For example, the UE 102 may store the at least one L1 measurement result in an internal memory of the UE 102. The at least one L1 measurement result may also be referred to as at least one measurement result of a second measurement type.

[0187] The UE 102 may have obtained the at least one L1 measurement result prior to determining that the at least one condition is fulfilled. Alternatively, the UE 102 may obtain the at least oneL1 measurement result by performing at least one L1 measurement after determining that the condition is fulfilled and before executing the conditional cell change.

[0188] The at least one L1 measurement result and the at least one L3 measurement result may be obtained by measuring at least one signal metric such as RSRP and / or RSRQ from at least one of: a reference signal transmitted on the first cell 121 (from the first network device 104), and / or a reference signal transmitted on a second cell 122 (from a second network device 104B). The second cell 122 may also be referred to as a candidate cell or a target cell.

[0189] The at least one L1 measurement result and the at least one L3 measurement result may be based on a same reference signal type, such as a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS). In other words, the measurement result(s) reported by the UE 102 may be of the same reference signal type as the measurement that triggered the measurement report. For example, if an SSB-based L3 condition is used for evaluating the at least one condition for triggering the conditional cell change, and the UE 102 is also configured with SSB-based and CSI-RS-based L1 measurement, the UE 102 may report the SSB-based L1 measurement.

[0190] If the reference signal type for L1 and L3 measurement is different, and for example CSI-RS based L3 measurement triggers the conditional cell change and the UE 102 is not configured to perform CSI-RS based L1 measurement for the same cell, then the UE 102 may not report the L1 measurement, or the UE 102 may report the L1 measurement of the different reference signal type (e.g., CSI-RS based L1 measurement).

[0191] At 706, the first network device 104 (first cell 121) may start to forward data (e.g., unsent or unacknowledged data related to this UE 102) to the second network device 104B associated with the second cell 122.

[0192] The second network device 104B may refer to another access node (e.g., another gNB) controlling the second cell 122. Alternatively, the first cell 121 and the second cell 122 may be controlled by the same access node.

[0193] Herein the terms “first network device” and “second network device” are used to distinguish the network devices, and they do not necessarily refer to a specific order or specific identifiers of the network devices. Similarly, the terms “first cell” and “second cell” are used to distinguish the cells, and they do not necessarily refer to a specific order or specific identifiers of the cells.

[0194] At 707, based on or in response to determining that the at least one condition is fulfilled, the UE 102 executes the conditional cell change for switching the UE 102 from the first cell 121 to the second cell 122.

[0195] During or after the cell change, the UE 102 generates and transmits a measurement report to the second network device 104B via the second cell 122, wherein the measurement reportcomprises the at least one L1 measurement result and the at least one L3 measurement result. In other words, the UE 102 may report the at least one L1 measurement result and the at least one L3 measurement result to the second network device 104B based on or in response to completing the conditional cell change. For example, the measurement results may be reported in a Msg5, an RRC reconfiguration complete message, or any subsequent message indicating measurement result(s) to be reported.

[0196] For example, after the cell change is completed, the UE 102 may transmit a message (e.g., an RRC reconfiguration complete message) to the second network device 104B to indicate the availability of the at least one L1 measurement result and the at least one L3 measurement result, and the second network device 104B may then request or configure the UE 102 to report the measurement results. In this case, the UE 102 may report the measurement results based on the request or configuration.

[0197] The at least one L1 measurement result may comprise a latest L1 measurement result that is available when determining that the at least one condition is fulfilled, or when executing the conditional cell change.

[0198] At 708, the second network device 104B (second cell 122) may adjust one or more parameters related to triggering cell changes in the second cell 122 controlled by the second network device 104B, wherein the adjustment is based at least partly on the at least one L1 measurement result and the at least one L3 measurement result. For example, based on the received information, the second network device 104B (second cell 122) may change the thresholds that trigger the conditional cell change so that the cell change is performed at the same time (or same location) and the cell border is consistent.

[0199] It should be noted that the adjustment may not be performed instantaneously based on a single UE's measurement results, but the aim may instead be for long-term parameter adjustment. Thus, the second network device 104B may be learning based on multiple UEs' measurement reports and optimize the settings for the entire cell 122. In other words, adjustment may be performed as part of a self-organizing network (SON) framework.

[0200] FIG. 8 illustrates a flow chart according to an example embodiment of a method A1 for storing at least one measurement result. The method A1 may be performed by an apparatus 1200 depicted in FIG. 12. For example, the apparatus 1200 may be, or comprise, or be comprised in, a user device (i.e., UE) 100, 102.

[0201] According to a first aspect, the method A1 comprises at least the following.

[0202] Referring to FIG. 8, in block 801 , the apparatus 1200 receives, from a first network device 104, a measurement configuration for a first measurement type, wherein the measurement configuration indicates at least one condition for reporting at least one measurement result of the first measurement type or for triggering a cell change.

[0203] In block 802, the apparatus 1200 determines whether the at least one condition is fulfilled.

[0204] In block 803, based on determining that the at least one condition is fulfilled (block 802: yes), the apparatus 1200 stores at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type.

[0205] In block 804, the apparatus 1200 reports the at least one measurement result of the first measurement type to the first network device 104 or to a second network device 104B. I n other words, the apparatus 1200 may transmit a measurement report comprising the at least one measurement result of the first measurement type. Herein a measurement result may also be referred to as a measurement sample.

[0206] According to a second aspect, there is provided the method A1 of the first aspect, further comprising receiving, from the first network device or from the second network device, an indication indicating whether to report the at least one measurement result of the second measurement type.

[0207] According to a third aspect, there is provided the method A1 of the first or second aspect, further comprising reporting the at least one measurement result of the second measurement type to the first network device 104 or to the second network device 104B.

[0208] According to a fourth aspect, there is provided the method A1 of any preceding aspect, wherein the at least one measurement result of the second measurement type comprises a latest measurement result of the second measurement type that is available when determining that the at least one condition is fulfilled.

[0209] According to a fifth aspect, there is provided the method A1 of any of the first to third aspects, wherein the at least one measurement result of the second measurement type comprises a latest measurement result of the second measurement type that is available when reporting the at least one measurement result of the first measurement type.

[0210] According to a sixth aspect, there is provided the method A1 of any preceding aspect, wherein the at least one measurement result of the second measurement type is reported to the first network device in a measurement report together with the at least one measurement result of the first measurement type.

[0211] According to a seventh aspect, there is provided the method A1 of any preceding aspect, wherein the at least one measurement result of the second measurement type is reported to the second network device based on completing the cell change from a first cell associated with the first network device to a second cell associated with the second network device.

[0212] FIG. 9 illustrates a flow chart according to an example embodiment of a method B1 for receiving at least one measurement result. The method B1 may be performed by an apparatus 1300 depicted in FIG. 13. For example, the apparatus 1300 may be, or comprise, or be comprised in, a network device suchas the first network device 104 or the second network device 104B (e.g., an access node of a radio access network).

[0213] According to an eighth aspect, the method B1 comprises at least the following.

[0214] Referring to FIG. 9, in block 901, the apparatus 1300 generates, a measurement configuration for a first measurement type, wherein the measurement configuration indicates at least one condition for reporting at least one measurement result of the first measurement type or for triggering a cell change.

[0215] In block 902, the apparatus 1300 transmits the measurement configuration to a user device 100, 102, wherein fulfilling the at least one condition causes or indicates the user device 100, 102 to store at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type.

[0216] In block 903, based on transmitting the measurement configuration, the apparatus 1300 receives, from the user device 100, 102, the at least one measurement result of the first measurement type.

[0217] According to a ninth aspect, there is provided the method B1 of the eighth aspect, further comprising transmitting, to the user device 100, 102, an indication indicating whether to report the at least one measurement result of the second measurement type.

[0218] According to a tenth aspect, there is provided the method B1 of the eighth or ninth aspect, further comprising receiving, from the user device 100, 102, the at least one measurement result of the second measurement type corresponding to the at least one measurement result of the first measurement type.

[0219] According to an eleventh aspect, there is provided the method B1 of the tenth aspect, further comprising adjusting one or more parameters related to triggering cell changes in a cell controlled by the apparatus 1300, wherein the adjustment is based at least partly on the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type.

[0220] According to a twelfth aspect, there is provided the method A1 of any of the first to seventh aspects, or the method B1 of any of the eighth to eleventh aspects, wherein the first measurement type comprises layer 1 measurements, and the second measurement type comprises layer 3 measurements.

[0221] According to a thirteenth aspect, there is provided the method A1 of any of the first to seventh aspects, or the method B1 of any of the eighth to eleventh aspects, wherein the first measurement type comprises layer 3 measurements, and the second measurement type comprises layer 1 measurements.

[0222] According to a fourteenth aspect, there is provided the method A1 of any of the first to seventh or twelfth to thirteenth aspects, or the method B1 of any of the eighth to thirteenth aspects, wherein the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type are based on a same reference signal type.

[0223] According to a fifteenth aspect, there is provided the method A1 of any of the first to seventh or twelfth to fourteenth aspects, or the method B1 of any of the eighth to fourteenth aspects, wherein the measurement configuration comprises at least one of: a measurement event configuration or a measurement reporting configuration.

[0224] According to another aspect, there is provided an apparatus 1200 comprising means for causing the apparatus 1200 to perform at least the method A1 of any of the first to seventh or twelfth to fifteenth aspects.

[0225] According to another aspect, there is provided an apparatus 1300 comprising means for causing the apparatus 1300 to perform at least the method B1 of any of the eighth to fifteenth aspects.

[0226] According to another aspect, there is provided an apparatus 1200 comprising at least one processor 1210, and at least one memory 1220 storing instructions that, when executed by the at least one processor 1210, cause the apparatus 1200 at least to perform at least the method A1 of any of the first to seventh or twelfth to fifteenth aspects.

[0227] According to another aspect, there is provided an apparatus 1300 comprising at least one processor 1310, and at least one memory 1320 storing instructions 1322 that, when executed by the at least one processor 1310, cause the apparatus 1300 at least to perform at least the method B1 of any of the eighth to fifteenth aspects.

[0228] According to another aspect, there is provided a computer program or a computer-readable medium (e.g., a non-transitory computer-readable medium) comprising program instructions which, when executed by an apparatus 1200, cause the apparatus 1200 to perform at least the method A1 of any of the first to seventh or twelfth to fifteenth aspects.

[0229] According to another aspect, there is provided a computer program or a computer-readable medium (e.g., a non-transitory computer-readable medium) comprising program instructions which, when executed by an apparatus 1300, cause the apparatus 1300 to perform at least the method B1 of any of the eighth to fifteenth aspects.

[0230] FIG. 10 illustrates a flow chart according to an example embodiment of a method A2 for storing at least one measurement result. The method A2 may be performed by an apparatus 1200 depicted in FIG. 12. For example, the apparatus 1200 may be, or comprise, or be comprised in, a user device (i.e., UE) 100, 102.

[0231] According to a first aspect, the method A2 comprises at least the following.

[0232] Referring to FIG. 10, in block 1001, the apparatus 1200 receives, from a first network device 104 controlling a first cell 121 , a measurement configuration for a first measurement type, wherein the measurement configuration indicates at least one condition for triggering a cell change;

[0233] In block 1002, the apparatus 1200 determines, based on at least one measurement result of the first measurement type, whether the at least one condition is fulfilled.

[0234] In block 1003, based on determining that the at least one condition is fulfilled (block 1002: yes), the apparatus 1200 stores (e.g., in an internal memory of the apparatus 1200) at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type.

[0235] In block 1004, the apparatus 1200 executes or performs the cell change from the first cell 121 to a second cell 122.

[0236] In block 1005, the apparatus 1200 reports, to a second network device 104B controlling the second cell 122, based on or in response to completing the cell change, the at least one measurement result of the first measurement type, and the at least one measurement result of the second measurement type.

[0237] According to a second aspect, there is provided the method A2 of the first aspect, further comprising: receiving, from the second network device 104B, an indication indicating whether to report the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type, wherein the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type are reported based on the indication indicating to report the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type.

[0238] According to a third aspect, there is provided the method A2 of any preceding aspect, wherein the at least one measurement result of the second measurement type comprises the latest measurement result of the second measurement type that is available when determining that the at least one condition is fulfilled.

[0239] According to a fourth aspect, there is provided the method A2 of the first or second aspect, wherein the at least one measurement result of the second measurement type comprises the latest measurement result of the second measurement type that is available when executing the cell switch.

[0240] According to a fifth aspect, there is provided the method A2 of any preceding aspect, wherein the measurement configuration comprises at least one of: a measurement event configuration or a measurement reporting configuration.

[0241] FIG. 11 illustrates a flow chart according to an example embodiment of a method B2 for receiving measurement results. The method B2 may be performed by an apparatus 1300 depicted in FIG.13. For example, the apparatus 1300 may be, or comprise, or be comprised in, a network device such as the first network device 104 or the second network device 104B (e.g., an access node of a radio access network).

[0242] According to a sixth aspect, the method B2 comprises at least the following.

[0243] Referring to FIG. 11, in block 1101, the apparatus 1300 executes or performs a cell change for a user device 100, 102 from a first cell 121 to a second cell 122 controlled by the apparatus 1300.

[0244] In block 1102, the apparatus 1300 receives, from the user device 100, 102, based on or in response to completing the cell change, at least one measurement result of a first measurement type, and at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type.

[0245] According to a seventh aspect, there is provided the method B2 of the sixth aspect, further comprising: transmitting, to the user device 100, 102, an indication indicating whether to report the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type.

[0246] According to an eighth aspect, there is provided the method B2 of the sixth or seventh aspect, further comprising: adjusting one or more parameters related to triggering cell changes in the second cell 122 controlled by the apparatus 1300, wherein the adjustment is based at least partly on the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type.

[0247] According to a ninth aspect, there is provided the method A2 of any of the first to fifth aspects, or the method B2 of any of the sixth to eighth aspects, wherein the first measurement type comprises layer 1 measurements, and the second measurement type comprises layer 3 measurements.

[0248] According to a tenth aspect, there is provided the method A2 of any of the first to fifth aspects, or the method B2 of any of the sixth to eighth aspects, wherein the first measurement type comprises layer 3 measurements, and the second measurement type comprises layer 1 measurements.

[0249] According to an eleventh aspect, there is provided the method A2 of any of the first to fifth aspects or ninth to tenth aspects, or the method B2 of any of the sixth to tenth aspects, wherein the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type are based on a same reference signal type.

[0250] According to another aspect, there is provided an apparatus 1200 comprising means for causing the apparatus 1200 to perform at least the method A2 of any of the first to fifth or ninth to eleventh aspects.

[0251] According to another aspect, there is provided an apparatus 1300 comprising means for causing the apparatus 1300 to perform at least the method B2 of any of the sixth to eleventh aspects.

[0252] According to another aspect, there is provided an apparatus 1200 comprising at least one processor 1210, and at least one memory 1220 storing instructions that, when executed by the at least one processor 1210, cause the apparatus 1200 at least to perform at least the method A2 of any of the first to fifth or ninth to eleventh aspects.

[0253] According to another aspect, there is provided an apparatus 1300 comprising at least one processor 1310, and at least one memory 1320 storing instructions 1322 that, when executed by the at least one processor 1310, cause the apparatus 1300 at least to perform at least the method B2 of any of the sixth to eleventh aspects.

[0254] According to another aspect, there is provided a computer program or a computer-readable medium (e.g., a non-transitory computer-readable medium) comprising program instructions which, when executed by an apparatus 1200, cause the apparatus 1200 to perform at least the method A2 of any of the first to fifth or ninth to eleventh aspects.

[0255] According to another aspect, there is provided a computer program or a computer-readable medium (e.g., a non-transitory computer-readable medium) comprising program instructions which, when executed by an apparatus 1300, cause the apparatus 1300 to perform at least the method B2 of any of the sixth to eleventh aspects.

[0256] The blocks, related functions, and information exchanges (messages) described above by means of FIGS. 4 to 11 are in no absolute chronological order, and some of them may be performed simultaneously or in an order differing from the described one. Other functions can also be executed between them or within them, and other information may be sent, and / or other rules applied. Some of the blocks or part of the blocks or one or more pieces of information can also be left out or replaced by a corresponding block or part of the block or one or more pieces of information.

[0257] FIG. 12 illustrates an example of an apparatus 1200 comprising means for performing one or more of the example embodiments (e.g., the method A1 of FIG. 8, the method A2 of FIG. 10, or the functionalities of the UE 100 or 102 of FIGS. 4 to 7) described above. For example, the apparatus 1200 may be an apparatus such as, or comprising, or comprised in, a user device (i.e., UE) 100, 102.

[0258] The apparatus 1200 may comprise a circuitry or a chipset applicable for realizing one or more of the example embodiments described above. For example, the apparatus 1200 may comprise at least one processor 1210. The at least one processor 1210 interprets instructions (e.g., computer program instructions) and processes data. The at least one processor 1210 may comprise one or more programmable processors. The at least one processor 1210 may comprise programmable hardware with embedded firmware and may, alternatively or additionally, comprise one or more application-specific integrated circuits (ASICs).

[0259] The at least one processor 1210 is coupled to at least one memory 1220. The at least one processor is configured to read and write data to and from the at least one memory 1220. The at least one memory 1220 may comprise one or more memory units. The memory units may be volatile or nonvolatile. It is to be noted that there may be one or more units of non-volatile memory and one or more units of volatile memory or, alternatively, one or more units of non-volatile memory, or, alternatively, one or moreunits of volatile memory. Volatile memory may be for example random-access memory (RAM), dynamic random-access memory (DRAM) or synchronous dynamic random-access memory (SDRAM). Non-volatile memory may be for example read-only memory (ROM), programmable read-only memory (PROM), electronically erasable programmable read-only memory (EEPROM), flash memory, optical storage or magnetic storage. In general, memories may be referred to as non-transitory computer readable media. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM). The at least one memory 1220 stores computer readable instructions that are executed by the at least one processor 1210 to perform one or more of the example embodiments described above. For example, non-volatile memory stores the computer readable instructions, and the at least one processor 1210 executes the instructions using volatile memory for temporary storage of data and / or instructions. The computer readable instructions may refer to computer program code.

[0260] The computer readable instructions may have been pre-stored to the at least one memory 1220 or, alternatively or additionally, they may be received, by the apparatus, via an electromagnetic carrier signal and / or may be copied from a physical entity such as a computer program product. Execution of the computer readable instructions by the at least one processor 1210 causes the apparatus 1200 to perform one or more of the example embodiments described above. That is, the at least one processor and the at least one memory storing the instructions may provide the means for providing or causing the performance of any of the methods and / or blocks described above.

[0261] In the context of this document, a “memory” or “computer-readable media” or “computer-readable medium” may be any non-transitory media or medium or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0262] The apparatus 1200 may further comprise, or be connected to, an input unit 1230. The input unit 1230 may comprise one or more interfaces for receiving input. The one or more interfaces may comprise, for example, at least one of: one or more temperature, motion and / or orientation sensors, one or more cameras, one or more accelerometers, one or more microphones, one or more buttons and / or one or more touch detection units. Further, the input unit 1230 may comprise an interface to which external devices may connect to.

[0263] The apparatus 1200 may also comprise an output unit 1240. The output unit may comprise or be connected to one or more displays capable of rendering visual content, such as a light emitting diode (LED) display, a liquid crystal display (LCD) and / or a liquid crystal on silicon (LCoS) display. The outputunit 1240 may further comprise one or more audio outputs. The one or more audio outputs may be for example loudspeakers.

[0264] The apparatus 1200 further comprises a connectivity unit 1250. The connectivity unit 1250 enables wireless connectivity to one or more external devices. The connectivity unit 1250 comprises at least one transmitter and at least one receiver that may be integrated to the apparatus 1200 or that the apparatus 1200 may be connected to. The at least one transmitter comprises at least one transmission antenna, and the at least one receiver comprises at least one receiving antenna. The connectivity unit 1250 may comprise an integrated circuit or a set of integrated circuits that provide the wireless communication capability for the apparatus 1200. Alternatively, the wireless connectivity may be a hardwired applicationspecific integrated circuit (ASIC). The connectivity unit 1250 may also provide means for performing at least some of the blocks or functions of one or more example embodiments described above. The connectivity unit 1250 may comprise one or more components, such as: power amplifier, digital front end (DFE), analog-to-digital converter (ADC), digital-to-analog converter (DAC), frequency converter, (de)modulator, and / or encoder / decoder circuitries, controlled by the corresponding controlling units.

[0265] It is to be noted that the apparatus 1200 may further comprise various components not illustrated in FIG. 12. The various components may be hardware components and / or software components.

[0266] FIG. 13 illustrates an example of an apparatus 1300 comprising means for performing one or more of the example embodiments (e.g., the method B1 of FIG. 9, the method B2 of FIG. 11 , or the functionalities of the first cell 121 or second cell 122 of FIGS. 4 to 7) described above. For example, the apparatus 1300 may be, or comprise, or be comprised in, a network device such as the first network device 104 or the second network device 104B (e.g., an access node of a radio access network).

[0267] The apparatus 1300 may comprise, for example, a circuitry or a chipset applicable for realizing one or more of the example embodiments described above. The apparatus 1300 may be an electronic device comprising one or more electronic circuitries. The apparatus 1300 may comprise a communication control circuitry 1310 such as at least one processor, and at least one memory 1320 storing instructions 1322 which, when executed by the at least one processor, cause the apparatus 1300 to carry out one or more of the example embodiments described above. Such instructions 1322 may, for example, include computer program code (software). The at least one processor and the at least one memory storing the instructions may provide the means for providing or causing the performance of any of the methods and / or blocks described above.

[0268] The processor is coupled to the memory 1320. The processor is configured to read and write data to and from the memory 1320. The memory 1320 may comprise one or more memory units. The memory units may be volatile or non-volatile. It is to be noted that there may be one or more units of nonvolatile memory and one or more units of volatile memory or, alternatively, one or more units of non-volatilememory, or, alternatively, one or more units of volatile memory. Volatile memory may be for example randomaccess memory (RAM), dynamic random-access memory (DRAM) or synchronous dynamic random-access memory (SDRAM). Non-volatile memory may be for example read-only memory (ROM), programmable readonly memory (PROM), electronically erasable programmable read-only memory (EEPROM), flash memory, optical storage or magnetic storage. In general, memories may be referred to as non-transitory computer readable media. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM). The memory 1320 stores computer readable instructions that are executed by the processor. For example, non-volatile memory stores the computer readable instructions, and the processor executes the instructions using volatile memory for temporary storage of data and / or instructions.

[0269] The computer readable instructions may have been pre-stored to the memory 1320 or, alternatively or additionally, they may be received, by the apparatus, via an electromagnetic carrier signal and / or may be copied from a physical entity such as a computer program product. Execution of the computer readable instructions causes the apparatus 1300 to perform one or more of the functionalities described above.

[0270] The memory 1320 may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and / or removable memory. The memory may comprise a configuration database for storing configuration data, such as a current neighbour cell list, and, in some example embodiments, structures of frames used in the detected neighbour cells.

[0271] The apparatus 1300 may further comprise or be connected to a communication interface 1330, such as a radio unit, comprising hardware and / or software for realizing communication connectivity with one or more wireless communication devices according to one or more communication protocols. The communication interface 1330 comprises at least one transmitter (Tx) and at least one receiver (Rx) that may be integrated to the apparatus 1300 or that the apparatus 1300 may be connected to. The communication interface 1330 may provide means for performing some of the blocks and / or functions (e.g., transmitting and receiving) for one or more example embodiments described above. The communication interface 1330 may comprise one or more components, such as: power amplifier, digital front end (DFE), analog-to-digital converter (ADC), digital-to-analog converter (DAC), frequency converter, (de)modulator, and / or encoder / decoder circuitries, controlled by the corresponding controlling units.

[0272] The communication interface 1330 provides the apparatus with radio communication capabilities to communicate in the wireless communication network. The communication interface may, for example, provide a radio interface to one or more UEs 100, 102. The apparatus 1300 may further comprise or be connected to another interface towards a core network 110, such as the network coordinator apparatusor AMF, and / or to other access nodes of the wireless communication network.

[0273] The apparatus 1300 may further comprise a scheduler 1340 that is configured to allocate radio resources. The scheduler 1340 may be configured along with the communication control circuitry 1310 or it may be separately configured.

[0274] It is to be noted that the apparatus 1300 may further comprise various components not illustrated in FIG. 13. The various components may be hardware components and / or software components.

[0275] 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 analog, digital and / or quantum circuitry); and b) combinations of hardware circuit(s) and software, such as (as applicable): i) a combination of analog, digital and / or quantum hardware circuit(s) with software / firmware and ii) any or all portions of hardware processor(s) (including digital and / or quantum processor(s)) with software, and memory(ies) that work together to cause an apparatus, such as a mobile device, computing device, or server, to perform various functions; and c) any or all portions of hardware circuit(s), such as microprocessor(s), processor(s) and / or quantum processor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0276] 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.

[0277] The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus(es) of example embodiments may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be carried out through modules of at least one chipset (for example procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via variousmeans, as is known in the art. Additionally, the components of the systems described herein may be rearranged and / or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

[0278] It will be understandable to a person skilled in the art that, as technology advances, the proposed concept may be implemented in various ways within the scope of the claims. The embodiments are not limited to the example embodiments described above, but may vary within the scope of the claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate, not to restrict, the embodiments.

Claims

1. CLAIMS1. An apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:receive, from a first network device controlling a first cell, a measurement configuration for a first measurement type, wherein the measurement configuration indicates at least one condition for triggering a cell change;determine, based on at least one measurement result of the first measurement type, whether the at least one condition is fulfilled;based on determining that the at least one condition is fulfilled,store at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type;execute the cell change from the first cell to a second cell; andreport, to a second network device controlling the second cell, based on completing the cell change, the at least one measurement result of the first measurement type, and the at least one measurement result of the second measurement type.

2. The apparatus of claim 1, further being caused to:receive, from the second network device, an indication indicating whether to report the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type,wherein the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type are reported based on the indication indicating to report the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type.

3. The apparatus of any preceding claim, wherein the at least one measurement result of the second measurement type comprises the latest measurement result of the second measurement type that is available when determining that the at least one condition is fulfilled.

4. The apparatus of any of claims 1 to 2, wherein the at least one measurement result of the second measurement type comprises the latest measurement result of the second measurement type that is available when executing the cell switch.

5. The apparatus of any preceding claim, wherein the measurement configuration comprises at least one of: a measurement event configuration or a measurement reporting configuration.

6. An apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:execute a cell change for a user device to a cell controlled by the apparatus; and receive, from the user device, based on completing the cell change, at least one measurement result of a first measurement type, and at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type.

7. The apparatus of claim 6, further being caused to:transmit, to the user device, an indication indicating whether to report the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type.

8. The apparatus of claim 6 or 7, further being caused to:adjust one or more parameters related to triggering cell changes in the cell controlled by the apparatus, wherein the adjustment is based at least partly on the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type.

9. The apparatus of any preceding claim, wherein the first measurement type comprises layer 1 measurements, and the second measurement type comprises layer 3 measurements.

10. The apparatus of any of claims 1 to 8, wherein the first measurement type comprises layer 3 measurements, and the second measurement type comprises layer 1 measurements.

11. The apparatus of any preceding claim, wherein the at least one measurement result of the first measurement type and the at least one measurement result of the second measurement type are based on a same reference signal type.

12. A method comprising:receiving, from a first network device controlling a first cell, a measurement configuration for a first measurement type, wherein the measurement configuration indicates at least one condition for triggering a cell change;determining, based on at least one measurement result of the first measurement type, whether the at least one condition is fulfilled;based on determining that the at least one condition is fulfilled,storing at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type;executing the cell change from the first cell to a second cell; andreporting, to a second network device controlling the second cell, based on completing the cell change, the at least one measurement result of the first measurement type, and the at least one measurement result of the second measurement type.

13. A method comprising:executing a cell change for a user device; andreceiving, from the user device, based on completing the cell change, at least one measurement result of a first measurement type, and at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type.

14. A non-transitory computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following:receiving, from a first network device controlling a first cell, a measurement configuration for a first measurement type, wherein the measurement configuration indicates at least one condition for triggering a cell change;determining, based on at least one measurement result of the first measurement type, whether the at least one condition is fulfilled;based on determining that the at least one condition is fulfilled,storing at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type;executing the cell change from the first cell to a second cell; andreporting, to a second network device controlling the second cell, based on completing the cell change, the at least one measurement result of the first measurement type, and the at least one measurement result of the second measurement type.

15. A non-transitory computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following:executing a cell change for a user device to a cell controlled by the apparatus; andreceiving, from the user device, based on completing the cell change, at least one measurement result of a first measurement type, and at least one measurement result of a second measurement type corresponding to the at least one measurement result of the first measurement type.

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