Channel measurements and reports

Abstract

The present disclosure relates to the field of telecommunication and in particular to devices, methods, apparatuses and computer readable storage media for performing a first channel measurement associated with a first cell based on a first spatial parameter; performing a second channel measurement associated with a second cell based on a second spatial parameter; determining whether at least one condition associated with the first spatial parameter and the second spatial parameter is fulfilled; and transmitting, when the at least one condition is fulfilled, a channel state information, CSI, report to a network entity, wherein the CSI report is based on the first channel measurement and the second channel measurement

Description

CHANNEL MEASUREMENTS AND REPORTSFIELD

[0001] Embodiments of the present disclosure relates to the field of telecommunication and inparticular to devices, methods, apparatuses and computer readable storage media for handlingchannel measurements and reports.BACKGROUND

[0002] In the handover types until Rel-17 of 3GPP, a serving cell change is triggered by layer 3(L3) measurements and is done by RRC signalling for change of primary cell (PCell) and / or primarysecondary cell (PSCell). All cases require reconfiguration of upper layers (e.g., RRC or PDCP)and / or resetting of lower layers (e.g., MAC and / or PHY) which leads to longer latency, largeroverhead and longer interruption time than beam level mobility. Rel-18 of 3GPP has introducedlayer 1 (L1) / layer 2 (L2) based mobility also known as a lower layer triggered mobility (LTM) toenable a serving cell change via L1 / L2 signalling, while keeping configuration of the upper layers and / or minimizing changes of configuration of the lower layers. This helps to reduce the latency, overhead and interruption time during handover. The LTM supports both intra-distributed unit (DU) and intra-central unit (CU)-inter-DU mobility. During the LTM, the user plane is continued whenever possible (e.g. intra-DU), without reset, with the target cell to avoid data loss and the additional delay of data recovery. 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] In the first aspect, there is provided an apparatus (e.g., user device) comprising at leastone processor; and at least one memory storing instructions that, when executed by the at leastone processor, cause the apparatus at least to: perform a first channel measurement associatedwith a first cell based on a first spatial parameter; perform a second channel measurementassociated with a second cell based on a second spatial parameter; determine whether at leastone condition associated with the first spatial parameter and the second spatial parameter isfulfilled; and transmit, when the at least one condition is fulfilled, a channel state information,CSI, report to a network entity, wherein the CSI report is based on the first channel measurementand the second channel measurement.

[0005] In the second aspect, there is provided an apparatus (e.g., network entity) comprising atleast one processor; and at least one memory storing instructions that, when executed by the atleast one processor, cause the apparatus at least to: receive, from a user device, a channel stateinformation (CSI) report. The CSI report may be based on a first channel measurement associatedwith a first cell and a second channel measurement associated with a second cell. The CSI reportmay be received when at least one condition associated with a first spatial parameter for the firstchannel measurement and a second spatial parameter for the second channel measurement isfulfilled.

[0006] In the third aspect, there is provided a method comprising steps of: performing a firstchannel measurement associated with a first cell based on a first spatial parameter; performinga second channel measurement associated with a second cell based on a second spatialparameter; determining whether at least one condition associated with the first spatialparameter and the second spatial parameter is fulfilled; and transmitting, when the at least onecondition is fulfilled, a channel state information, CSI, report to a network entity, wherein the CSIreport is based on the first channel measurement and the second channel measurement.

[0007] In the fourth aspect, there is provided a method comprising a step of: receiving, from auser device, a channel state information (CSI) report. The CSI report may be based on a firstchannel measurement associated with a first cell and a second channel measurement associatedwith a second cell. The CSI report may be received when at least one condition associated witha first spatial parameter for the first channel measurement and a second spatial parameter forthe second channel measurement is fulfilled.

[0008] In the fifth aspect, there is provided an apparatus (e.g., user device) comprising at leastone processor; and at least one memory storing instructions that, when executed by the at leastone processor, cause the apparatus at least to: perform a first channel measurement associatedwith a first cell based on a first spatial parameter; perform a second channel measurementassociated with a second cell based on a second spatial parameter; transmit a channel stateinformation, CSI, report to a network entity. The CSI report may be based on the first channelmeasurement and the second channel measurement. The CSI report may comprise at least oneof: a flag indicating whether at least one condition associated with the first spatial parameter andthe second spatial parameter is fulfilled; or at least one correction factor, CF, to be applied to atleast one of the first channel measurement or the second channel measurement.

[0009] In the sixth aspect, there is provided an apparatus (e.g., network entity) comprising atleast one processor; and at least one memory storing instructions that, when executed by the atleast one processor, cause the apparatus at least to: receive, from a user device, a channel stateinformation (CSI) report. The CSI report may be based on a first channel measurement associatedwith a first cell and a second channel measurement associated with a second cell. The CSI reportmay comprise at least one of: a flag indicating whether at least one condition associated with afirst spatial parameter for the first channel measurement and a second spatial parameter for thesecond channel measurement is fulfilled; or at least one correction factor, CF, to be applied to atleast one of the first channel measurement or the second channel measurement.

[0010] In the seventh aspect, there is provided a method comprising steps of: performing a firstchannel measurement associated with a first cell (e.g., serving cell) based on a first spatialparameter; performing a second channel measurement associated with a second cell based on asecond spatial parameter; transmitting a channel state information, CSI, report to a networkentity. The CSI report may be based on the first channel measurement and the second channelmeasurement. The CSI report may comprises at least one of: a flag indicating whether at leastone condition associated with the first spatial parameter and the second spatial parameter isfulfilled; or at least one correction factor, CF, to be applied to at least one of the first channelmeasurement or the second channel measurement.

[0011] In the eighth aspect, there is provided a method comprising a step of: receiving, from auser device, a channel state information (CSI) report. The CSI report may be based on a firstchannel measurement associated with a first cell and a second channel measurement associatedwith a second cell. The CSI report may comprise at least one of: a flag indicating whether at leastone condition associated with a first spatial parameter for the first channel measurement and asecond spatial parameter for the second channel measurement is fulfilled; or at least onecorrection factor (CF) to be applied to at least one of the first channel measurement or the secondchannel measurement.

[0012] In the ninth aspect, there is provided a computer program comprising instructions which,when executed by the apparatus (e.g., the user device or the network entity), cause the apparatusto perform the embodiments of the third, fourth, seventh or eighth aspect.

[0013] In the tenth aspect, a computer-readable storage medium has stored thereon thecomputer program of the ninth aspect.

[0014] In the eleventh aspect, a non-transitory computer readable medium stores thereon thecomputer program of the tenth aspect.

[0015] Other features and advantages of the embodiments of the present disclosure will alsobe apparent from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles ofembodiments of the disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments of the disclosure are presented in the sense of examples and theiradvantages are explained in greater detail below, with reference to the accompanying drawings.

[0017] FIG.1A illustrates an example of a wireless communication network;

[0018] FIG.1B illustrates an example of a system;

[0019] FIG. 2 illustrates a mobility scenario in NR frequency range 2 (FR2), with one candidatecell.

[0020] FIG.3 illustrates another mobility scenario in NR FR2, with two candidate cells

[0021] FIG. 4 illustrates embodiments of the first CSI reporting scheme.

[0022] FIG. 5 illustrates embodiments of the second CSI reporting scheme.

[0023] FIG. 6 illustrates an example of an apparatus.

[0024] FIG. 7 illustrates an example of an apparatus.

[0025] Throughout the drawings, the same or similar reference numerals may represent thesame or similar element. DETAILED DESCRIPTION

[0026] The following embodiments are exemplifying. Principle of the present disclosure willnow be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitationas to the scope of the disclosure. Embodiments described herein may be implemented in variousmanners other than the ones described below.

[0027] In the following description and claims, unless defined otherwise, all technical andscientific terms used herein may have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0028] References in the present disclosure to “one embodiment,” “an embodiment,” “anexample embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, element or characteristic, but it is not necessary that everyembodiment includes the particular feature, structure, element or characteristic. Moreover, suchphrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that itis within the knowledge of one skilled in the art to affect such feature, structure, element orcharacteristic in connection with other embodiments whether or not explicitly described.

[0029] It shall be understood that although the terms “first,” “second” and the like may be usedherein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or”includes any and all combinations of one or more of the listed terms.

[0030] As used herein, “at least one of the following: ” and “atleast 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.

[0031] As used herein, unless stated explicitly, performing a step “in response to A” does notindicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0032] The terminology used herein is for the purpose of describing particular embodimentsonly and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify thepresence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0033] As used in this application, the term “circuitry” may refer to one or more or all of thefollowing: (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0034] This definition of circuitry applies to all uses of this term in this application, including inany 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.

[0035] As used herein, the term “communication network” refers to a network following anysuitable communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE- Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G), the sixth generation (6G) communication protocols, and / or any other protocols either currently known or to be developedin the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0036] As used herein, the term “network entity” refers to a node in a communication networkvia which a user device accesses the network and receives services therefrom. The network entitymay refer to a network device, a base station (BS) or an access point (AP), for example, a node B(NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a radioaccess network (RAN) node, a new generation RAN (NG-RAN) node, a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-groundnetwork device such as a satellite network device, a low earth orbit (LEO) satellite and ageosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture includes a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node includes a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0037] The term “user device” refers to any end device that may be capable of wirelesscommunication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a PortableSubscriber Station, a Mobile Station (MS), a terminal device or an Access Terminal (AT). The userdevice may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voiceover IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personaldigital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle- mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or otherwearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications(e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wirelessdevices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, andthe like. The user device may also correspond to a Mobile Termination (MT) part of an IAB node(e.g., a relay node). In the following description, the terms “user device”, “communication device”,“terminal”, “terminal device”, “user equipment” and “UE” may be used interchangeably.

[0038] As used herein, the term “resource,” “transmission resource,” “resource block,” “physicalresource block” (PRB), “uplink resource,” “downlink resource” or “sidelink resource” may refer to any resource for performing a communication, for example, a communication between a user device and a network entity, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0039] FIG. 1A depicts an example of a simplified wireless communication network showingsome physical and logical network entities. The connections shown in FIG.1A 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.1A.

[0040] The example embodiments described herein are not, however, restricted to the wirelesscommunication network given as an example but a person skilled in the art may apply the embodiments described herein to other wireless communication networks provided with necessary properties.

[0041] The example wireless communication network shown in FIG. 1A includes an accessnetwork, such as a radio access network (RAN), and a core network 110.

[0042] FIG. 1A shows user equipment (UE) 100, 102 configured to be in a wireless connectionon one or more communication channels in a radio cell with an access node (AN) 104 of an access network. The AN 104 may be 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 wireless connection (e.g., radio link) from a UE 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 to the UE may be called downlink (DL) or forward link. UE 100 may also communicate directly with 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 or access point etc. entity suitable for providing such functionalities.

[0043] The access network may comprise more than one access node, in which case the accessnodes may also be configured to communicate with one another over links, wired or wireless. These links between access nodes may be used for sending and receiving control plane signaling and also for routing data from one access node to another access node.

[0044] The access node may comprise a computing device configured to control the radioresources of the access node. The access node may also be referred to as a network entity, a base station, a base transceiver station (BTS), an access point, a cell site, a radio access node or any other type of node capable of being in a wireless connection with a UE (e.g., UEs 100, 102). The access node may include or be coupled to transceivers. From the transceivers of the access node, a connection may be provided to an antenna unit that establishes bi-directional radio links to UEs 100, 102. The antenna unit may comprise an antenna or antenna element, or a plurality of antennas or antenna elements.

[0045] The access node 104 may further be connected to a core network (CN) 110. The corenetwork 110 may comprise an evolved packet core (EPC) network and / or a 5th generation 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 a mobility management entity (MME). The 5GC may comprise network functions, such as a user plane function (UPF), an access and mobility management function (AMF), and a location management function (LMF).

[0046] The core network 110 may also be able to communicate with one or more externalnetworks 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.

[0047] The illustrated UE 100, 102 is one type of an apparatus to which resources on the airinterface may be allocated and assigned. The UE 100, 102 may also be called a wirelesscommunication 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 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 awireless modem (e.g., an alarm or measurement device, etc.), a laptop computer, a desktopcomputer, 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 sensor comprising a wireless modem, or any computing device comprising a wireless modem integrated in a vehicle.

[0048] It should be appreciated that a UE may also be a nearly exclusive uplink-only device, ofwhich an example may be a camera or video camera loading images or video clips to a network. A UE may also be a device having capability to operate in an Internet of Things (IoT) 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. The UE may also utilize cloud. In some applications, the computation may be carried out in the cloud or in another UE.

[0049] The wireless communication network may also be able to support the usage of cloudservices, 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 wireless communication network may also comprise a central control entity, or the like, providing facilities for wireless communication networks of different operators to cooperate for example in spectrum sharing.

[0050] 5G enables using multiple input – multiple output (MIMO) antennas in the access node104 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.

[0051] In 5G wireless communication networks, access nodes and / or UEs may have multipleradio interfaces, namely below 6GHz, cmWave and mmWave, and also being integrable withexisting legacy radio access technologies, such as the LTE. Integration with the LTE may be implemented, for example, as a system, where macro coverage may be provided by the LTE, and 5G radio interface access may come from small cells by aggregation to the LTE. In other words, a 5G wireless communication network may support both inter-RAT operability (such as LTE-5G) andinter-RI operability (inter-radio interface operability, such as below 6GHz – cmWave – mmWave).One of the concepts considered to be used in 5G wireless communication networks may be network slicing, in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the substantially same infrastructure to run services that have different requirements on latency, reliability, throughput and mobility.

[0052] In some example embodiments, an access node (e.g., access node 104) may comprise: aradio unit (RU) 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 may enable the centralization of CUs relative to the cell sites and DUs, whereasDUs may be more distributed and may even remain at cell sites. The CU and DU together mayalso be referred to as baseband or a baseband unit (BBU). The CU and DU may also be comprised in a radio access point (RAP).

[0053] The CU 108 may be a logical node hosting radio resource control (RRC), service dataadaptation protocol (SDAP) and / or packet data convergence protocol (PDCP), of the NR protocolstack for an access node. 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 accessnode. The operations of the DU may be at least partly controlled by the CU. It should also beunderstood that the distribution of functions between DU 105 and CU 108 may vary depending on implementation. The CU 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. The CU 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.

[0054] Cloud computing systems may also be used to provide the CU 108 and / or DU 105. A CUprovided by a cloud computing system may be referred to as a virtualized CU (vCU). In additionto 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).

[0055] Edge cloud may be brought into the access network (e.g., RAN) by utilizing networkfunction 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) of an access node. 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. Application of cloud RAN architecture enables RAN real-time functions being carried out at the 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).

[0056] It should also be understood that the distribution of functions between core networkoperations and access node operations may differ in future wireless communication networks compared to that of the LTE or 5G, 6G, or even be non-existent. Some other technology advancements that may be used include big data and all-IP, which may change the way wireless communication networks are being constructed and managed. 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.

[0057] A 5G wireless communication network (“5G network”) may also comprise a non-terrestrial 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, enabling more extensive network coverage. Possible use cases may be providing servicecontinuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or for passengerson board of vehicles, or ensuring service availability for critical communications, and future railway / maritime / aeronautical communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular mega-constellations (systems in which hundreds of (nano)satellites are deployed). A given satellite 106 in the mega-constellation may cover several satellite-enabled network entities that create on-ground cells. The on-ground cells may be created through an on-ground relayaccess node or by an access node 104 located on-ground or in a satellite.

[0058] It is obvious for a person skilled in the art that the access node 104 depicted in FIG. 1Ais just an example of a part of an access network (e.g., a radio access network) and in practice, the access network may comprise a plurality of access nodes, the UEs 100, 102 may have access to a plurality of radio cells, and the 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.

[0059] Additionally, in a geographical area of an access network (e.g., 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 ofup to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The access node(s)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.

[0060] For fulfilling the need for improving performance of access networks, the concept of“plug-and-play” access nodes may be introduced. An 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, or HNB-GW (not shown in FIG.1A). An HNB-GW, which may be installed within an operator’s access network, may aggregate traffic from a large number of Home eNodeBs or Home gNodeBs back to a core network of the operator.

[0061] FIG.1B illustrates an example of a system, to which some example embodiments may beapplied. FIG.1B may be understood to depict a part of the wireless communication network of FIG.1A, but with greater accuracy with respect to cell re-selection. The system comprises at least a UE 100 and a plurality of RAN nodes 104, 104B, 104C, 104D (e.g., gNBs) 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 RAN nodes 104, 104B, 104C, 104D are shown in FIG.1B, it should be noted that the number of cells and RAN nodes may also be higher or lower than four. In addition, each of the cells is controlled by each of the RAN nodes in FIG. 1B, but one or more cells may be controlled by a single RAN node.

[0062] With cell selection, the UE 100 searches for a suitable cell of the selected public landmobile network (PLMN) or selected stand-alone non-public network (SNPN), chooses that cell to provide available services, and monitors its control channel. This procedure is defined as "camping on the cell". If the UE 100 finds a more suitable cell, according to the cell re-selection criteria, the UE 100 re-selects onto that cell and camps on it. For example, cell re-selection may be based on measurements and evaluations of signal strength, quality, and / or other parameters of the current serving cell 121 and one or more neighboring cells 122, 123, 124. The UE 100 may autonomously make the decision to re-select a different cell in idle (RRC_IDLE) mode, or if the UE experiences a radio link failure.

[0063] 1. LTM procedure

[0064] Hereinafter, the LTM procedure that may be applied to the embodiments of thedisclosure, is explained.

[0065] LTM is a cell switch procedure, where UE’s serving cell (PCell or PSCell) is switched by thenetwork by sending an LTM cell switch command. An LTM switch command is currently assumed delivered by MAC signaling using a Medium Access Control Control Element (MAC CE). Hence, not using RRC signaling as a L3 based handover which is one of the current methods for changing between cells. LTM cell switch decision is currently assumed to be based on L1 measurementsthat are performed and reported using L1 measurement reports by the UE. Measurements andreporting are based on LTM candidate cell configuration provided by the network for one or moreLTM candidate cells. An LTM candidate cell may be neighboring cells or a UE’s current servingcells (e.g. SCells).

[0066] In Release-18, LTM measurements on a neighboring candidate cell are performed usingSynchronization Signal Blocks (SSBs, or Synchronized signals and PBCH blocks) transmitted by thecandidate cell for which the SSB configuration is provided to the UE.

[0067] Before the cell switch, network may optionally activate one or more TransmissionConfiguration Indicator (TCI) state(s) for one or more candidate cells. Once a candidate cell TCIstate is activated the UE may start tracking the time / frequency synchronization using the reference signals associated with the activated TCI state(s). The UE may also perform early UL synchronization before the cell switch if this is requested by the network.

[0068] The LTM procedure may be applied to the other embodiments of the present disclosure.

[0069] 2. Mobility scenario in NR FR2

[0070] FIG. 2 illustrates a mobility scenario in NR frequency range 2 (FR2), with one candidatecell.

[0071] Hereinafter, a user device (e.g., UE0) of embodiments of the disclosure may be one ofUEs 100 and 102. The user device may be equipped with one or more antenna panels (Pk, k = 1,2, …, M, where k denotes a panel index and M denotes a number of panels). For example, thenumber of panels in the user device in FIG. 2 may be M = 4 (i.e., P1, P2, P3, P4), but the number ofpanels (M) may be different according to the user device’s capability.

[0072] Each antenna panel (Pk) may comprise a corresponding antenna set (Ak) comprising twoor more antenna elements available for RX beamforming. Each panel Pk may consist of a uniqueset Ak of antenna elements, e.g., P1 has a set A1, P2 has a set A2, etc. The number of antennaelements in a set Ak is denoted by |Ak|. For example, in FIG. 2, |A1| = |A3| = 4 (top and bottompanels) and |A2| = |A4| = 8 (left and right panels).

[0073] When performing channel measurements on a given panel, the user device may combinereceived signals from only some (i.e., not all) antenna elements pertaining to that panel. Thesubset of antenna elements pertaining to panel Pk that are actually used for combining is denotedby Sk. For example, S1 denotes the subset of antenna elements pertaining to panel P1 that areactually used for combining, etc. The number of antenna elements in subset Sk is denoted by |Sk|.

[0074] There are 2|Ak|-1 non-empty subsets Sk of a set Ak. For example, for A1 with |A1| = 4,there are 15 (i.e., 24-1) possible non-empty subsets S1 when k=4, as follows:Single antenna Two antenna Three antenna Four (i.e., all) antenna element from set A1 elements from set A1 elements from set A1 elements from set A1 (i.e., |S1|=1) (i.e., |S1|=2) (i.e., |S1|=3) (i.e., |S1|=4) S1 S1 = {1} S1 = {1,2} S1 = {1,2,3} S1 = {1,2,3,4}S1 = {2} S1 = {1,3} S1 = {1,2,4}S1 = {3} S1 = {1,4} S1 = {1,3,4}S1 = {4} S1 = {2,3} S1 = {2,3,4}S1 = {2,4}S1 = {3,4}

[0075] When performing channel measurements on a given panel Pk, the UE may combine thesignals received on a subset Sk of the set Ak of available antenna elements (Sk ⊆ Ak).The RXbeamforming gain may increase (and the RX beamwidth may decrease) with the number ofantenna elements |Sk| from which signals are combined. For instance, the UE may performchannel measurements using a single antenna element (|Sk| = 1) on a panel, resulting in a relatively wide RX beam (w1, … , w4) with relatively low RX gain (and higher exposure to interference). Conversely, the UE may perform channel measurements by combining the signals from all available antenna elements (Sk= Ak) on a panel, resulting in a relatively narrow RX beam (e.g., n1) with relatively high RX gain (and lower exposure to interference).

[0076] Referring to FIG. 2, the UE0 has the antenna sets A2 and A4 on its left and right sides,respectively. Each of the antenna sets (A2 and A4) has 8 antenna elements. The UE0 also has the antenna sets A1 and A3 on its top and bottom sides, respectively. In this case, the antenna setsA1 and A3 have fewer (4) antenna elements than the A2 and A4.

[0077] In FIG.2, the UE (e.g., UE0) may be configured by a RRC signal (e.g., LTM-CSI-ReportConfig)to report channel state information (CSI) (e.g., network-controlled periodic, semi-persistent, oraperiodic CSI reporting, or UE event-triggered CSI reporting) based on channel measurements on reference signals (RS1, RS2… , RS12) (e.g., CSI-RS) transmitted in a serving cell (e.g., associated withbase station BS0) and reference signals (RS’1, RS’2 … , RS’12) transmitted in a candidate cell (e.g.,associated with base station BS1).

[0078] The purpose of such CSI reporting may be to allow the network device (BS0) to determinewhether the UE should switch to the candidate cell or remain in the serving cell. As the UE0moves away from BS0and approaches BS1, the received signal strength (e.g., RSRP) from the serving cell (e.g., from RS5, corresponding to the strongest beam in the serving cell) may become weaker, while the received signal strength (e.g., RSRP) from the candidate cell (e.g., from RS’2, corresponding to the strongest beam in the candidate cell) may become stronger. Based on the reported CSI, the network may instruct the UE to switch to the candidate cell, where it can be served via a stronger link.

[0079] However, as shown in FIG. 2, the UE0 may be able to perform channel measurementsusing different RX beams (also referred to as “spatial domain filters”), in particular with different RX beamwidths (i.e., corresponding to finer or coarser spatial resolution) and consequently different RX beamforming gains. For example, the UE may be equipped with multiple panels (P1, … , P4), each consisting of multiple antenna elements. Let Akdenote the set of antenna elements available for RX beamforming on panel Pk.

[0080] When performing channel measurements on a given panel Pk, the UE may combine thesignals received on a subset Sk of the set Ak of available antenna elements (Sk ⊆ Ak). The RXbeamforming gain may increase (and the RX beamwidth may decrease) with the number ofantenna elements |Sk| from which signals are combined. For instance, the UE0may performchannel measurements using a single antenna element (|Sk| = 1, where |Sk| denotes the numberof antenna elements in the subset Sk) on a panel (Pk), resulting in a relatively wide RX beam (w1, … ,w4) with relatively low RX gain (and higher exposure to interference). Conversely, the UE mayperform channel measurements by combining the signals from all available antenna elements (Sk= Ak) on a panel, resulting in a relatively narrow RX beam (e.g., n1) with relatively high RX gain (and lower exposure to interference).

[0081] Unfortunately, the network device (e.g., BS0 or BS1) has limited or no control over the RXbeamwidths (and consequently the RX beamforming gains) used by the UE when performing channel measurements. If the UE is allowed to report CSI based on channel measurements from different cells using (significantly) different RX beamwidths (and / or RX beamforming gains), the network may make suboptimal cell switch decisions.

[0082] For example, if the UE reports CSI based on channel measurements on RS5 using thenarrow, high-gain RX beam n1 and channel measurements on RS’2 using the wide, low-gain RX beam w3, the L1-RSRP (and / or L1-SINR) from the serving cell may remain stronger even when theUE is already significantly closer to the candidate cell managed by BS1. As a result, the networkdevice (BS0) may not instruct the UE0 to switch to the candidate cell (of BS1), even though it couldbe served via a stronger link there, if only the UE0 could refine its wide, low-gain RX beam w3 to a narrower, higher gain RX beam (n3, not shown) pointing to the candidate cell.

[0083] In addition, this may result in a larger uplink pathloss than necessary, thus requiringhigher UE TX power, which not only increases the UE energy consumption unnecessarily but may increase interference on other uplink transmissions.

[0084] FIG. 3 illustrates another mobility scenario in NR FR2, with two candidate cells (e.g.,associated with base stations BS1, BS2). In this case, the UE (UE0) may, in addition, report CSI based on channel measurements on RS’’10using the narrow, high-gain RX beam n2. Even though the UE is significantly closer to BS1 than BS2, the L1-RSRP (and / or L1-SINR) reported for RS’’10 may be stronger than the L1-RSRP (and / or L1-SINR) reported for RS’2, as a result of the higher RX beamforming gain (and finer spatial resolution) of the narrow, high-gain RX beam n2compared to the wide, low-gain RX beam w3. Thus, the network may be led to believe that a switch to LTMCandidate Cell 2 (managed by BS2) is desirable. Such a cell switch decision may not be justified ifin fact the UE0is capable of refining its wide, low-gain RX beam w3to a narrower, higher gain RX beam (n3, not shown) pointing to BS1.

[0085] It may be in the UE’s own interest to report CSI (e.g., L1-RSRP, L1-SINR) based on channelmeasurements on reference signals from different cells performed in such a way that the network can make optimal cell switch decisions and always serve the UE with the strongest possible link. However, the UE’s ability to determine the strongest possible link may require determining refined, high-gain RX beams (e.g., n2), which in turn depends on the network configuring the UE to perform channel measurements on reference signals (e.g., CSI-RS) transmitted repeatedly with a same TX beam (e.g., RS’’10), for example, a CSI-RS resource set with the “repetition” flag set. If the network does not properly configure the UE for such channel measurements (e.g., the UE has not been configured to measure on RS’2with the “repetition” flag set), the UE may not be able to refine some of its RX beams, or may not do so in a timely manner, especially RX beams pointingaway from the serving cell (e.g., w3), and situations such as those illustrated in FIGs. 2 or 3 mayoccur, regardless of UE implementation.

[0086] Moreover, CSI-RS transmissions with the “repetition” flag set are transmitted in a cell(e.g., LTM Candidate Cell 1) for the purpose of allowing RX beam refinement for a UE (e.g., UE1) which is served by that cell (not for UEs served by other cells, such as UE0), and such CSI-RS transmissions are usually transmitted on a CSI-RS beam (e.g., RS’9) reported by that UE (UE1), which may in general not match the CSI-RS beam (e.g., RS’2) that is appropriate for a UE servedby another cell (e.g., UE0). The CSI-RS transmissions with repetition enabled are not meant (andshould not be expected) to be transmitted periodically on every CSI-RS beam (e.g., RS’1, … , RS’12), as this would incur significant and unjustified overhead (that is not the intention of the feature), but rather on demand (e.g., aperiodically) and on a specific CSI-RS beam, e.g., upon receiving a beam report from a UE (e.g., UE1) served by the cell (e.g., LTM Candidate Cell 1) indicating an appropriate CSI-RS beam (e.g., RS’9) for transmitting the CSI-RS with repetition enabled.

[0087] The mobility related channel measurements (e.g., based on SSB or CSI-RS) have so fareither been assumed to be performed by the UE with a same (or similar) RX beamwidth (i.e., not significantly different RX beamwidths), or otherwise the different RX beamwidths have not beenexplicitly taken into account by the network device (e.g., BS0) when making cell switch decisions.

[0088] The mobility scenarios explained by FIGs. 2 and 3 and the description thereof may beapplied to the lower layer triggered mobility (LTM) scenarios.

[0089] 3. Handling channel measurements with different RX beamwidth

[0090] Hereinafter, it is proposed to enhance the CSI reporting framework to take into accountthe possibility of different RX beamwidths (and / or consequently different RX beamforming gains)being used by the UE when performing channel measurements on reference signals (e.g., SSBand / or CSI-RS) from different cells (e.g., serving cell, candidate cell(s)). The CSI reportingframework may be applied for the LTM as discussed above.

[0091] In one set of embodiments, a UE is caused (via specification and / or configuration) to:(1) use a same (or similar) RX beamwidth and / or a same (or similar) RX beamforming gain and / or a same (or similar) number of antenna elements for RX beamforming, when performing channel measurements across different cells; (2) use a narrowest (or widest) attainable RX beamwidth and / or a highest (or lowest) attainable RX beamforming gain and / or a largest (or smallest) possible number of antenna elements for RX beamforming, when performing the channel measurements across different cells; or(3) apply correction factor(s) to the channel measurements prior to CSI reporting.

[0092] In another set of embodiments, the UE is caused (via specification and / or configuration)to: (1) indicate in the CSI report whether / which channel measurements across different cells have been performed in accordance with at least one condition related to the RX beamwidth and / or the RX beamforming gain and / or the number of antenna elements used for RX beamforming at the time of channel measurement, and / or (2) indicate correction factor(s) to be applied by the network on the reported channel measurements.

[0093] 4. Embodiments of a first CSI reporting scheme

[0094] The user device(s) explained hereinafter may be the UE (e.g., UEs 100, 102 or UE0) of FIG.1A, 1B, 2 or 3. The network entity(-ies) explained hereinafter may be the AN 104, satellite 106,or BS0of FIG.1A, 1B, 2 or 3.

[0095] In one set of embodiments, the reporting of CSI based on channel measurements acrossdifferent cells performed using (significantly) different RX beamwidths (and / or RX beamforminggains) may be constrained. The reporting of CSI may be intended for the LTM.

[0096] More specifically, reporting CSI (e.g., L1-RSRP, L1-SINR) based on channel measurementson reference signals (e.g., SSB, CSI-RS) from different cells performed using (significantly) differentRX beamwidths (and / or RX beamforming gains) may be constrained (e.g., forbidden or limited insome way), either by the specification or by an explicit indication from the network entity.

[0097] 4.1 Constraint via UE measurement requirements

[0098] In this embodiment, the specification (e.g., by 3GPP technical standard documents) maymandate the user device to use a same (or similar) RX beamwidth (and / or RX beamforming gain)when performing channel measurements on reference signals (e.g., SSB, CSI-RS) from differentcells for LTM. A same (or similar) RX beamwidth may translate into a same (or similar) number ofantenna elements used for combining received signals during channel measurement.

[0099] Additionally or alternatively, the specification may constrain such channelmeasurements to use a single antenna element (corresponding to a widest attainable RX beam and / or lowest attainable RX beamforming gain).

[0100] Additionally or alternatively, the specification may constrain such channelmeasurements to use all available antenna elements on a panel (corresponding to a narrowest attainable RX beam and / or highest attainable RX beamforming gain).

[0101] Additionally or alternatively, the specification may define a highest tolerable difference(beamwidth difference threshold, Δφth) between the RX beamwidths used to conduct the corresponding measurements. Similarly, the specification may define a highest tolerable difference (gain difference threshold, ΔGth) between the RX beamforming gains used to conduct the corresponding measurements.

[0102] Additionally or alternatively, the user device may be able to form a narrower RX beam(thus, a higher RX beamforming gain) on some panels than on others. For example, the UE0 inFIG. 2 may comprise a larger number of antenna elements (e.g., |A2| = |A4| = 8) on its left andright sides and a smaller number of antenna elements (e.g., |A1| = |A3| = 4) on its top and bottom sides. In this case, the specification may allow the UE to report CSI based on channel measurements performed using different RX beamwidths, e.g., the narrowest attainable RX beamwidths on each panel (corresponding to the highest attainable RX beamforming gains on each panel).

[0103] As disclosed above, the specification may prevent the user device from reporting CSIbased on channel measurements on reference signals from different cells performed using widelydifferent RX beamwidths when in fact the user device is capable of forming corresponding RXbeams with a same (or similar) RX beamwidths towards the different cells.

[0104] Below tables 1 to 3 are examples of how the specification constrains the UEmeasurement requirements according to the above embodiments.

[0105] [Table 1]- TS 38.133, Section 8.X TCI state activation for LTM candidate cell- The UE shall activate UE beams for TCI state activation with the same number of antennaelements among candidate cells and serving cells in FR2; when necessary, a correction factor (CF) can be used to ensure the reported measurements correspond to equal conditions.

[0106] [Table 2]- TS 38.133 Section 9.14 Intra-frequency L1-RSRP measurement for neighbor cells- The UE shall report L1-RSRP measurements performed with a RX beam which is formedwith the same number of antenna elements among candidate and serving cells; when necessary, a correction factor (CF) can be used in FR2 to ensure that the reported measurements correspond to equal conditions.

[0107] [Table 3]- TS 38.133 Section 9.15 Inter-frequency L1-RSRP measurement for neighbor cells- The UE shall report L1-RSRP measurements performed with a RX beam which is formedwith the same number of antenna elements among candidate and serving cells; when necessary, a correction factor (CF) can be used in FR2 to ensure that the reported measurements correspond to equal conditions.

[0108] 4.2 Constraint via explicit configuration from the network device

[0109] In this embodiment, when the network entity configures the user device to report CSI(e.g., via CSI-ReportConfig or LTM-CSI-ReportConfig), the network entity may explicitly indicateto the user device that the channel measurements across different cells shall be performed using(to the extent possible) a same (or similar) RX beamwidth and / or RX beamforming gain.

[0110] In one example, the network entity may indicate that the channel measurements acrossdifferent cells shall be performed using a widest attainable RX beam (e.g., using a single antenna element) on a respective panel, and / or a lowest attainable RX beamforming gain. For instance,referring to FIGs. 2 and 3, the network entity (BS0) may instruct the UE0 to perform the channelmeasurements on the wide RX beams (w1, …, w4) corresponding to reception on a single antenna element on each panel.

[0111] Additionally or alternatively, the network entity may indicate that the channelmeasurements across different cells shall be performed using a refined RX beam (e.g., using 2 antenna elements) on a respective panel, with the number of antenna elements being the samefor all channel measurements. In this case, the network device may need to ensure that a properrefined RX beam (e.g., n1, n2) can be determined by the UE0, e.g., by configuring the UE tomeasure on reference signals (e.g., CSI-RS) with a “repetition” flag enabled, thus indicating thatthe user device can assume the reference signals are transmitted by the network entity using asame TX beam (e.g., the TX beam of RS5, RS’2 or RS’’10), enabling the UE to perform RX beam sweeping of different refined RX beams.

[0112] Additionally or alternatively, the network may indicate that the channel measurementsacross different cells shall be performed using a narrowest attainable RX beam on a respective panel (and / or highest attainable RX beamforming gain), corresponding to using all available antenna elements on the panel.

[0113] Additionally or alternatively, the UE may be configured to include in the CSI reportchannel measurements performed using RX beams whose beamwidths are within a beamwidth difference threshold (Δφth) (e.g., Δφth= 10deg), or whose RX beamforming gains are within a gain difference threshold (ΔGth) (e.g., ΔGth= 3dB).

[0114] 4.3 Reporting CSI based on corrected channel measurements

[0115] In this embodiment, the user device is not constrained (as above) to perform the channelmeasurements in any specific way. Instead, the UE is configured (or expected) by the network to apply correction factor(s) (CF) to the channel measurements from different cells prior to CSI reporting and to report CSI based on the corrected channel measurements.

[0116] For example, referring to FIG. 3, even though the UE may not have performed channelmeasurements on RS’2 using a narrow, high-gain RX beam, the UE may report CSI based on channel measurements on RS’2 performed using the wide, low-gain RX beam w3, corrected by amultiplication factor (or an addition term, in dB).

[0117] In one example, the CF may be based on a maximum additional RX beamforming gainthat the user device is able to attain (e.g., corresponding to using all available antenna elements).Such additional RX beamforming gain may be known to the user device or estimated by the userdevice based on prior channel measurements which were performed using all available antennaelements.

[0118] Additionally or alternatively, the user device may determine the correction factor itselfas CF (dB) = 10 log10(|Ak| / |Sk|), where Akdenotes the (complete) set of antenna elementsavailable for RX beamforming on panel Pk, and Sk denotes a subset of antenna elements used forchannel measurement (Sk ⊆ Ak). For example, in case the UE uses a single antenna element inpanel P3 (i.e., |S3| = 1, |A3| = 4), the correction factor may be determined as CF = 10 log10(4) = 6 dB.

[0119] Additionally or alternatively, the CF may be a function of a RX beamforming gaindifference between respective RX beams.

[0120] In some cases, the CSI report configuration (e.g., CSI-ReportConfig or LTM-CSI-ReportConfig) may indicate whether the user device should apply correction factor(s) to thereported channel measurements. The user device may indicate to the network entity its capabilityto provide corrected channel measurements.

[0121] 5. Embodiments of a second CSI reporting scheme

[0122] The user device(s) explained hereinafter may be the UE (e.g., UEs 100, 102 or UE0) of FIG.1A, 1B, 2 or 3. The network entity(-ies) explained hereinafter may be the AN 104, satellite 106,or BS0 of FIG.1A, 1B, 2 or 3.

[0123] In this second CSI reporting scheme, reporting CSI based on channel measurements onreference signals from different cells performed using (significantly) different RX beamwidths isnot constrained, i.e., the user device may retain full freedom to use different RX beamwidthswhen performing the channel measurements.

[0124] In order to avoid suboptimal cell switch decisions by the network entity, the user deviceindicates whether the reported channel measurements may be meaningfully compared by thenetwork entity, or otherwise provides correction factors to allow for a meaningful comparison.

[0125] 5.1 Comparability flag

[0126] In this embodiment, the user device may indicate to the network entity via a binary“comparability flag” (0 / 1) whether the reported channel measurements on reference signals (e.g.,CSI-RS) from different cells may be assumed by the network to have been performed according to specified rule(s) that ensure meaningful comparison. For example, the UE may set thecomparability flag if all reported channel measurements have been performed using the widestattainable RX beams (w1, … w4), or if all reported channel measurements have been performed using the narrowest attainable RX beams.

[0127] Additionally or alternatively, the user device may set the comparability flag if all reportedchannel measurements have been performed by combining signals from a same (or maximum)number of antenna elements.

[0128] Additionally or alternatively, the user device may indicate which among a set of reportedchannel measurements may be meaningfully compared for cell switch decisions and / or whichchannel measurements may not be meaningfully compared. In other words, the user device mayindicate which among a set of reported channel measurements have been performed according to specified rule(s) and / or which channel measurements have not been performed according tospecified rule(s). Multi-bit indicators may be used to enable such indication.

[0129] 5.2 Correction factor indication

[0130] In this embodiment, the user device may accompany the channel measurements withone or more correction factor(s) allowing for meaningful comparison at the network side. Forexample, referring to FIG. 3, even though the user device may not have performed channelmeasurements on RS’2 using a narrow, high-gain RX beam, the user device may report channelmeasurements on RS’2performed using the wide, low-gain RX beam w3, accompanied by the CFaccounting for a maximum additional RX beamforming gain that the user device can attain (e.g.,corresponding to using all available antenna elements).

[0131] 6. Example disclosures based on the signal diagrams

[0132] FIG.4 illustrates embodiments of the first CSI reporting scheme.

[0133] The network environment comprises the user device 100 and the network entity 104.The user device 100 may be the same entity as the UE (e.g., UE 100 or 102 or UE0) of FIG. 1A, 1B,2 or 3, respectively. The network entity 104 may be the same entity as the AN 104 or the satellite106 of FIG.1A or 1B, or the BS0of FIG.2 or 3.

[0134] The user device or the network entity may comprise at least one processor; and at leastone memory storing instructions that, when executed by the at least one processor, cause theuser device or the network entity to perform the procedure shown by FIG. 4.

[0135] FIG.4 shows constrained CSI reporting methods based on section 4. Referring to FIG. 4,the user device 100 performs a first channel measurement (e.g., L1-RSRP, L1-SINR) associatedwith a first cell based on a first spatial parameter (S410). The first cell is a serving cell that ismanaged / controlled by the network entity 104.

[0136] The user device 100 performs a second channel measurement (e.g., L1-RSRP, L1-SINR)associated with a second cell based on a second spatial parameter (S420). The second cell is acandidate cell that may be managed / controlled by another network entity (not shown).

[0137] The user device 100 determines whether at least one condition associated with the firstspatial parameter and the second spatial parameter is fulfilled (S430).

[0138] When the at least one condition is fulfilled, the user device 100 may transmit a channelstate information (CSI) report (e.g., periodic / semi-persistent / aperiodic or event-triggered) to anetwork entity 104, and the network entity 104 may receive the CSI report (S440). The CSI reportof S440 may be generated based on the first channel measurement and the second channelmeasurement. The CSI report may be transmitted from the user device 100 to the network entity 104 for a lower layer triggered mobility (LTM).

[00139] The first spatial parameter may include at least one of a first spatial domain filter(e.g., n1, w1 of FIG.2) or a first combined signal from a first subset (S1) of antenna elements amonga first set (A1) of antenna elements corresponding to a first receiver branch (e.g., a first panel P1).The spatial domain filter may allow signals to be transmitted / received in a certain direction. Thespatial domain filter may correspond to a set of phase shifts (one phase shift per antennaelement), that a receiver of the user device applies to i) direct a receive beam towards a desiredangular direction and / or ii) shape the corresponding beamforming gain (equivalently, beamwidth) of the receive beam accordingly.

[0140] The second spatial parameter may include at least one of a second spatial domain filter(e.g., n2, w2) or a second combined signal from a second subset (S2) of antenna elements amonga second set (A2) of antenna elements corresponding to a second receiver branch.

[0141] Each of the first receiver branch and the second receiver branch may be one of the panelsof the user device, and the first receiver branch and the second receiver branch may be differentfrom each other.

[0142] The at least one condition of S430 may be at least one of:c1) a beamwidth difference (Δφ) between a first beamwidth (φ1) associated with the first spatial domain filter (e.g., n1, w1) and a second beamwidth (φ2) associated with the second spatial domain filter (e.g., n2, w2) is below a beamwidth difference threshold (|Δφ| < Δφth); c2) the first beamwidth (φ1) is the narrowest attainable beamwidth (φmin,1) at the firstreceiver branch and the second beamwidth (φ2) is a narrowest attainable beamwidth (φmin,2) at the second receiver branch; orc3) the first beamwidth (φ1) is a widest attainable beamwidth (φmax,1) at the first receiverbranch and the second beamwidth (φ2) is a widest attainable beamwidth (φmax,2) at thesecond receiver branch.

[0143] The at least one condition of S430 may be at least one of:c4) a gain difference (ΔG) between a first beamforming gain (G1) associated with the first spatial domain filter (e.g., n1, w1) and a second beamforming gain (G2) associated with the second spatial domain filter (e.g., n2, w2) is below a gain difference threshold (|ΔG| < ΔGth); c5) the first beamforming gain (G1) is a highest attainable beamforming gain (Gmax,1) atthe first receiver branch and the second beamforming gain (G2) is a highest attainablebeamforming gain (Gmax,2) at the second receiver branch; orc6) the first beamforming gain (G1) is a lowest attainable beamforming gain (Gmin,1) atthe first receiver branch and the second beamforming gain (G2) is a lowest attainablebeamforming gain (Gmin,2) at the second receiver branch.

[0144] The at least one condition of S430 may be at least one of:c7) a size of the first subset and a size of the second subset are equal (i.e., |S1| = |S2|); c8) the first subset is equal to the first set (i.e., S1 = A1) and the second subset is equal tothe second set (i.e., S2 = A2); c9) each of the first subset and the second subset has one antenna element (i.e., |S1| =|S2| = 1); or c10) a difference between sizes of the first subset and the second subset is less than apredefined number (i.e., ||S1|-|S2||< Y).

[0145] Alternatively or additionally, the CSI report may be not transmitted if the at least onecondition is not fulfilled (S450).

[0146] Alternatively or additionally, the user device 100 may be further caused to apply at leastone correction factor (CF) to at least one of the first channel measurement or the second channelmeasurement (S460). The at least one CF may be applied when the at least one condition is notfulfilled at S430.

[0147] Then, the user device 100 may transmit the corrected CSI report to the network entity104 (S465). In this case, the CSI report may be based on at least one of the corrected first channelmeasurement or the corrected second channel measurement by the CF.

[0148] The at least one CF is based on at least one of:- the first spatial domain filter (e.g., n1, w1);- the second spatial domain filter (e.g., n2, w2);- the first subset (S1);- the second subset (S2);- the gain difference (ΔG) between the first beamforming gain (G1) and the secondbeamforming gain (G2); or -a maximum additional beamforming gain attainable by the apparatus.

[0149] The user device 100 may be further caused to at least one of:- transmit, to the network entity 104, an indication indicative of whether the apparatusis capable of applying the at least one CF; or- transmit, to the network entity 104, an indication indicative of the at least one CF thathas been applied.

[0150] The network device 104 may be further caused to at least one of:- receive, from the user device 100, an indication indicative of whether the user deviceis capable of applying at least one CF; or -receive, from the user device 100, an indication indicative of the at least one CF thathas been applied.

[0151] The user device 100 may be further caused to receive, from the network entity 104, aCSI report configuration indicating to apply the at least one correction factor when the at leastone condition is not fulfilled.

[0152] Alternatively or additionally, the user device 100 may be further caused to receive, fromthe network entity 104, an indication (e.g., via a RRC message including LTM-CSI-ReportConfig IE)indicating the at least one condition (S405). That is to say, the network entity 104 may transmitthe indication to the user device 100 via the RRC message.

[0153] The first cell may be a different cell from the second cell. For example, the first cell maybe a serving cell that is managed / controlled by the network entity 104, and the second cell maybe a neighboring cell (or target cell, candidate cell) that is managed / controlled by anothernetwork entity.

[0154] Alternatively or additionally, the procedure (or the method) of FIG. 4 may be performedby using a computer program. The computer program may comprise instructions, which, whenexecuted by an apparatus (e.g., the user device 100 or the network device 104), cause theapparatus to perform the method explained by FIG.4.

[0155] Alternatively or additionally, the computer-readable storage medium having storedthereon the computer program.

[0156] Alternatively or additionally, a non-transitory computer readable medium having storedthereon the computer program.

[0157] FIG. 5 illustrates embodiments of the second CSI reporting scheme.

[0158] The network environment comprises the user device 100 and the network entity 104.The user device 100 may be the same entity as the UE (e.g., UE 100 or 102 or UE0) of FIG. 1A, 1B,2 or 3, respectively. The network entity 104 may be the same entity as the AN 104 or the satellite106 of FIG.1A or 1B, or the BS0 of FIG.2 or 3.

[0159] The user device or the network entity may comprise at least one processor; and at leastone memory storing instructions that, when executed by the at least one processor, cause theuser device or the network entity to perform the procedure shown by FIG.5.

[0160] FIG. 5 shows unconstrained CSI reporting methods based on section 5. Referring to FIG.5, the user device 100 performs a first channel measurement (e.g., L1-RSRP, L1-SINR) associatedwith a first cell based on a first spatial parameter (S510). The first cell is a serving cell ismanaged / controlled by the network entity 104.

[0161] The user device 100 performs a second channel measurement (e.g., L1-RSRP, L1-SINR)associated with a second cell based on a second spatial parameter (S520). The second cell is acandidate cell that may be managed / controlled by another network entity (not shown).

[0162] The user device 100 transmits a channel state information (CSI) report (e.g.,periodic / semi-persistent / aperiodic or event-triggered) to a network entity 104, and the networkentity 104 receives the CSI report from the user device 100. In this case, the CSI report comprisesat least one of 1) a flag indicating whether at least one condition associated with the first spatialparameter and the second spatial parameter is fulfilled or 2) at least one correction factor (CF) tobe applied to at least one of the first channel measurement or the second channel measurement (S530).

[0163] The CSI report of S530 may be transmitted for a lower layer triggered mobility (LTM).The CSI report may be based on the first channel measurement and the second channelmeasurement.

[0164] The first spatial parameter may include at least one of a first spatial domain filter (e.g.,n1, w1) or a first combined signal from a first subset (S1) of antenna elements among a first set(A1) of antenna elements corresponding to a first receiver branch.

[0165] The second spatial parameter may include at least one of a second spatial domain filter(e.g., n2, w2) or a second combined signal from a second subset (S2) of antenna elements amonga second set (A2) of antenna elements corresponding to a second receiver branch.

[0166] Each of the first receiver branch and the second receiver branch may be one of the panelsof the user device, and the first receiver branch and the second receiver branch may be differentfrom each other.

[0167] The at least one condition may be at least one of:c1) a beamwidth difference (Δφ) between a first beamwidth (φ1) associated with the first spatial domain filter (e.g., n1, w1) and a second beamwidth (φ2) associated with the second spatial domain filter (e.g., n2, w2) is below a beamwidth difference threshold (|Δφ| < Δφth); c2) the first beamwidth (φ1) is the narrowest attainable beamwidth (φmin,1) at the firstreceiver branch and the second beamwidth (φ2) is a narrowest attainable beamwidth (φmin,2) at the second receiver branch; orc3) the first beamwidth (φ1) is a widest attainable beamwidth (φmax,1) at the first receiverbranch and the second beamwidth (φ2) is a widest attainable beamwidth (φmax,2) at thesecond receiver branch.

[0168] Additionally or alternatively, the at least one condition may be at least one of:c4) a gain difference (ΔG) between a first beamforming gain (G1) associated with the first spatial domain filter (e.g., n1, w1) and a second beamforming gain (G2) associated with the second spatial domain filter (e.g., n2, w2) is below a gain difference threshold (|ΔG| < ΔGth); c5) the first beamforming gain (G1) is a highest attainable beamforming gain (Gmax,1) atthe first receiver branch and the second beamforming gain (G2) is a highest attainablebeamforming gain (Gmax,2) at the second receiver branch; orc6) the first beamforming gain (G1) is a lowest attainable beamforming gain (Gmin,1) atthe first receiver branch and the second beamforming gain (G2) is a lowest attainablebeamforming gain (Gmin,2) at the second receiver branch.

[0169] Additionally or alternatively, the at least one condition may be at least one of:c7) a size of the first subset and a size of the second subset are equal (i.e., |S1| = |S2|); c8) the first subset is equal to the first set (i.e., S1 = A1) and the second subset is equal tothe second set (i.e., S2= A2); c9) each of the first subset and the second subset has one antenna element (i.e., |S1| =|S2| = 1); or c10) a difference between sizes of the first subset and the second subset is less than apredefined number (i.e., ||S1|-|S2||< Y).

[0170] The at least one correction factor is based on at least one of:- the first spatial domain filter (e.g., n1, w1);- the second spatial domain filter (e.g., n2, w2);- the first subset (S1);- the second subset (S2);- the gain difference (ΔG) between the first beamforming gain (G1) and the secondbeamforming gain (G2); or -a maximum additional beamforming gain attainable by the apparatus.

[0171] The user device 100 may be further caused to receive, from the network entity 104, aCSI report configuration indicating to apply the at least one correction factor (S505).

[0172] The user device 100 may be further caused to receive, from the network entity, anindication (e.g., via, a RRC message including a CSI-ReportConfig IE or an LTM-CSI-ReportConfigIE) indicating the at least one condition (S505).

[0173] The network device 104 may transmit the CSI report configuration and the indicationindicating the at least one condition to the user device 100 by using the same RRC message or byusing separate RRC messages.

[0174] The first cell may be a different cell from the second cell. For example, the first cell maybe a serving cell that is managed / controlled by the network entity 104, and the second cell maybe a neighboring cell (or target cell, candidate cell) that is managed / controlled by anothernetwork entity.

[0175] Alternatively or additionally, the procedure (or the method) of FIG. 5 may be performedby using a computer program. The computer program may comprise instructions, which, whenexecuted by an apparatus (e.g., the user device 100 or the network device 104), cause theapparatus to perform the method explained by FIG. 5.

[0176] Alternatively or additionally, the computer-readable storage medium having storedthereon the computer program.

[0177] Alternatively or additionally, a non-transitory computer readable medium having storedthereon the computer program.

[0178] FIG. 6 illustrates an example of an apparatus 600 comprising means for performing oneor more of the example embodiments described above. For example, the apparatus 600 may be,or comprise, or be comprised in, the user device 100. The apparatus 600 may perform theoperations disclosed in FIG.4 or 5.

[0179] The apparatus 600 may comprise a circuitry or a chipset applicable for realizing one ormore of the example embodiments described above. For example, the apparatus 600 maycomprise at least one processor 610. The at least one processor 610 interprets instructions (e.g., computer program instructions) and processes data. The at least one processor 610 may comprise one or more programmable processors. The at least one processor 610 may comprise programmable hardware with embedded firmware and may, alternatively or additionally, comprise one or more application-specific integrated circuits (ASICs).

[0180] The at least one processor 610 is coupled to at least one memory 620. The at least oneprocessor is configured to read and write data to and from the at least one memory 620. The at least one memory 620 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 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 more units of volatile memory. Volatile memory maybe 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 620 stores computer readable instructions that are executed by the at least one processor 610 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 610 executes the instructions using volatile memory for temporary storage of data and / or instructions. The computer readable instructions may refer to computer program code.

[0181] The computer readable instructions may have been pre-stored to the at least onememory 620 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 610 causes the apparatus 600 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.

[0182] 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).

[0183] The apparatus 600 may further comprise, or be connected to, an input unit 630. Theinput unit 630 may comprise one or more interfaces for receiving input. The one or more interfaces may comprise for example 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 630 may comprise an interface to which external devices may connect to.

[0184] The apparatus 600 may also comprise an output unit 640. The output unit may compriseor 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 output unit 640 may further comprise one or more audio outputs. The one or more audio outputs may be for example loudspeakers.

[0185] The apparatus 600 further comprises a connectivity unit 650. The connectivity unit 650enables wireless connectivity to one or more external devices. The connectivity unit 650 comprises at least one transmitter and at least one receiver that may be integrated to the apparatus 600 or that the apparatus 600 may be connected to. The at least one transmitter comprises at least one transmission antenna, and the at least one receiver comprises at least onereceiving antenna. The connectivity unit 650 may comprise an integrated circuit or a set ofintegrated circuits that provide the wireless communication capability for the apparatus 600. Alternatively, the wireless connectivity may be a hardwired application-specific integrated circuit (ASIC). The connectivity unit 650 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 650 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.

[0186] It is to be noted that the apparatus 600 may further comprise various components notillustrated in FIG. 6. The various components may be hardware components and / or softwarecomponents.

[0187] The apparatus 600 may perform or be applied with the embodiments described above.More specifically, the apparatus 600 may be the user device 100, and the user device 100 may beconfigured to perform one of the methods explained by using FIGs. 1A to 5.

[0188] FIG. 7 illustrates an example of an apparatus 700 comprising means for performing oneor more of the example embodiments described above. For example, the apparatus 700 may bean apparatus such as, or comprising, or comprised in, the network entity 104 or the networkdevice, and support the embodiments and examples described above.

[0189] The network entity 104 may also be referred to, for example, as a network element, anext generation radio access network (NG-RAN) node, a NodeB, an eNB, a gNB, a base transceiver station (BTS), a base station, an NR base station, a 5G base station, an access node, an access point (AP), a cell site, a relay node, a repeater, an integrated access and backhaul (IAB) node, an IAB donor node, a distributed unit (DU), a central unit (CU), a baseband unit (BBU), a radio unit (RU), a radio head, a remote radio head (RRH), or a transmission and reception point (TRP).

[0190] The apparatus 700 may comprise, for example, a circuitry or a chipset applicable forrealizing one or more of the example embodiments described above. The apparatus 700 may bean electronic device comprising one or more electronic circuitries. The apparatus 700 may comprise a communication control circuitry 710 such as at least one processor, and at least one memory 720 storing instructions 722 which, when executed by the at least one processor, cause the apparatus 700 to carry out one or more of the example embodiments described above. Such instructions 722 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.

[0191] The processor is coupled to the memory 720. The processor is configured to read andwrite data to and from the memory 720. The memory 720 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 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 more units 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-volatilememory 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 memory 720 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.

[0192] The computer readable instructions may have been pre-stored to the memory 720 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 700 to perform one or more of the functionalities described above.

[0193] The memory 720 may be implemented using any suitable data storage technology, suchas 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.

[0194] The apparatus 700 may further comprise or be connected to a communication interface730, 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 730 comprises at least one transmitter (Tx) and at least one receiver (Rx) that may be integrated to the apparatus 700 or that the apparatus 700 may be connected to. The communication interface 730 may provide means for performing some of the blocks for one or more example embodiments described above. The communication interface 730 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.

[0195] The communication interface 730 provides the apparatus with radio communicationcapabilities to communicate in the wireless communication network. The communication interface may, for example, provide a radio interface to one or more wireless communication devices. The apparatus 700 may further comprise or be connected to another interface towards a core network such as the network coordinator apparatus or AMF, and / or to the access nodes of the wireless communication network.

[0196] The apparatus 700 may further comprise a scheduler 740 that is configured to allocateradio resources. The scheduler 740 may be configured along with the communication control circuitry 710 or it may be separately configured.

[0197] It is to be noted that the apparatus 700 may further comprise various components notillustrated in FIG. 7. The various components may be hardware components and / or software components.

[0198] The apparatus 700 may perform or be applied with the embodiments described above.More specifically, the apparatus 700 may be the network device 104, and the network device 104may be configured to perform one of the methods explained by using FIGs. 1A to 5.

[0199] 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 various means, 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.

[0200] It will be obvious to a person skilled in the art that, as technology advances, the inventiveconcept may be implemented in various ways. 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

WHAT IS CLAIMED IS:

1. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least oneprocessor, cause the apparatus at least to:perform a first channel measurement associated with a first cell based on a first spatialparameter; perform a second channel measurement associated with a second cell based on a second spatial parameter; transmit a channel state information, CSI, report to a network entity,the CSI report being based on the first channel measurement and the secondchannel measurement, and the CSI report comprising at least one of: a flag indicating whether at least one condition associated with the first spatial parameter and the second spatial parameter is fulfilled; orat least one correction factor, CF, to be applied to at least one of the first channel measurement or the second channel measurement.

2. The apparatus of claim 1, wherein the first spatial parameter includes at least one of: a first spatial domain filter, or a first combined signal from a first subset of antenna elements among a first set of antenna elements corresponding to a first receiver branch, and wherein the second spatial parameter includes at least one of: a second spatial domain filter, or a second combined signal from a second subset of antenna elements among a second set of antenna elements corresponding to a second receiver branch.

3. The apparatus of claim 2, wherein the at least one condition is at least one of: c1) a beamwidth difference between a first beamwidth associated with the first spatial domain filter and a second beamwidth associated with the second spatial domain filter is below a beamwidth difference threshold; c2) the first beamwidth is a narrowest attainable beamwidth at the first receiver branchand the second beamwidth is a narrowest attainable beamwidth at the second receiver branch;or c3) the first beamwidth is a widest attainable beamwidth at the first receiver branch andthe second beamwidth is a widest attainable beamwidth at the second receiver branch.

4. The apparatus of claim 2, wherein the at least one condition is at least one of:c4) a gain difference between a first beamforming gain associated with the first spatial domain filter and a second beamforming gain associated with the second spatial domain filter is below a gain difference threshold; c5) the first beamforming gain is a highest attainable beamforming gain at the first receiver branch and the second beamforming gain is a highest attainable beamforming gain at the second receiver branch; or c6) the first beamforming gain is a lowest attainable beamforming gain at the firstreceiver branch and the second beamforming gain is a lowest attainable beamforming gain at thesecond receiver branch.

5. The apparatus of claim 2, wherein the at least one condition is at least one of: c7) a size of the first subset and a size of the second subset are equal; c8) the first subset is equal to the first set and the second subset is equal to the secondset; c9) each of the first subset and the second subset has one antenna element; orc10) a difference between the sizes of the first subset and the second subset is less than a predefined number.

6. The apparatus of any one of claims 2 to 5, wherein the at least one correction factor is based on at least one of: the first spatial domain filter; the second spatial domain filter; the first subset; the second subset; the gain difference between the first beamforming gain and the second beamforming gain; or a maximum additional beamforming gain attainable by the apparatus.

7. The apparatus of any one of claims 1 to 6, wherein the apparatus is further caused to:receive, from the network entity, a CSI report configuration indicating to apply the atleast one correction factor.

8. The apparatus of any one of claims 1 to 7, wherein the apparatus is further caused to:receive, from the network entity, an indication indicating the at least one condition.

9. The apparatus of any one of claims 1 to 8, wherein the first cell is a different cell from the second cell.

10. An apparatus comprising: at least one processor; andat least one memory storing instructions that, when executed by the at least oneprocessor, cause the apparatus at least to:receive, from a user device, a channel state information, CSI, report,wherein the CSI report is based on a first channel measurement associated with a firstcell and a second channel measurement associated with a second cell, andwherein the CSI report comprises at least one of:a flag indicating whether at least one condition associated with a first spatialparameter for the first channel measurement and a second spatial parameter forthe second channel measurement is fulfilled; orat least one correction factor, CF, to be applied to at least one of the first channel measurement or the second channel measurement.

11. The apparatus of claim 10, wherein the first spatial parameter includes at least one of: a first spatial domain filter, or a first combined signal from a first subset of antenna elements among a first set of antenna elements corresponding to a first receiver branch, and wherein the second spatial parameter includes at least one of: a second spatial domain filter, or a second combined signal from a second subset of antenna elements among a second set of antenna elements corresponding to a second receiver branch.

12. The apparatus of claim 11, wherein the at least one condition is at least one of: c1) a beamwidth difference between a first beamwidth associated with the first spatial domain filter and a second beamwidth associated with the second spatial domain filter is below a beamwidth difference threshold; c2) the first beamwidth is a narrowest attainable beamwidth at the first receiver branchand the second beamwidth is a narrowest attainable beamwidth at the second receiver branch;or c3) the first beamwidth is a widest attainable beamwidth at the first receiver branch andthe second beamwidth is a widest attainable beamwidth at the second receiver branch.

13. The apparatus of claim 11, wherein the at least one condition is at least one of: c4) a gain difference between a first beamforming gain associated with the first spatial domain filter and a second beamforming gain associated with the second spatial domain filter is below a gain difference threshold; c5) the first beamforming gain is a highest attainable beamforming gain at the first receiver branch and the second beamforming gain is a highest attainable beamforming gain at the second receiver branch; or c6) the first beamforming gain is a lowest attainable beamforming gain at the firstreceiver branch and the second beamforming gain is a lowest attainable beamforming gain at thesecond receiver branch.

14. The apparatus of claim 11, wherein the at least one condition is at least one of: c7) a size of the first subset and a size of the second subset are equal; c8) the first subset is equal to the first set and the second subset is equal to the secondset; c9) each of the first subset and the second subset has one antenna element, orc10) a difference between the sizes of the first subset and the second subset is less than a predefined number.

15. The apparatus of any one of claims 11 to 14, wherein the at least one correction factor is based on at least one of: the first spatial domain filter; the second spatial domain filter; the first subset; the second subset; the gain difference between the first beamforming gain and the second beamforming gain; or a maximum additional beamforming gain attainable by the apparatus.

16. The apparatus of any one of claims 11 to 15, wherein the apparatus is further causedto: transmit, to the user device, a CSI report configuration indicating to apply the at leastone correction factor.

17. The apparatus of any one of claims 11 to 16, wherein the apparatus is further causedto: transmit, to the user equipment, an indication indicating the at least one condition.

18. The apparatus of any one of claims 10 to17, wherein the first cell is a different cell from the second cell.

19. A method, performed by a user device, comprising:performing a first channel measurement associated with a first cell (e.g., serving cell)based on a first spatial parameter;performing a second channel measurement associated with a second cell based on asecond spatial parameter; transmitting a channel state information, CSI, report to a network entity,the CSI report being based on the first channel measurement and the secondchannel measurement, and the CSI report comprising at least one of: a flag indicating whether at least one condition associated with the first spatial parameter and the second spatial parameter is fulfilled; orat least one correction factor, CF, to be applied to at least one of the first channel measurement or the second channel measurement.

20. A method, performed by a network entity, comprising: receiving, from a user device, a channel state information, CSI, report,wherein the CSI report is based on a first channel measurement associated with a firstcell and a second channel measurement associated with a second cell, andwherein the CSI report comprises at least one of:a flag indicating whether at least one condition associated with a first spatialparameter for the first channel measurement and a second spatial parameter forthe second channel measurement is fulfilled; orat least one correction factor, CF, to be applied to at least one of the first channel measurement or the second channel measurement.

21. A computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform the method of any one of claims 19 and 20.

22. A computer-readable storage medium having stored thereon the computer programof claim 21.

23. A non-transitory computer readable medium having stored thereon the computer program of claim 21.

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