Channel state information reference resource for CSI acquisition measurement for a mobility candidate cell

Abstract

Example embodiments of the present disclosure are directed to channel state information (CSI) reference resource (RS) for CSI acquisition measurement for a mobility candidate cell. The method comprises: receiving, from a second apparatus, a mobility configuration at least comprising a configuration of channel state information reference signals (CSI- RSs) for a CSI acquisition of at least one candidate cell; receiving a cell switch command indicating the at least one candidate cell as a target cell; and determining, based on at least a reference point determined by a timing of a reception of the cell switch command, a timeline for at least one of a CSI report carrying the information related to CSI acquisition to the target cell or a CSI reference resource.

Description

CHANNEL STATE INFORMATION REFERENCE RESOURCE FOR CSI ACQUISITION MEASUREMENT FOR A MOBILITY CANDIDATE CELLFIELDS

[0001] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium for channel state information (CSI) reference resource (RS) for CSI acquisition measurement for a mobility candidate cell.BACKGROUND

[0002] With the continuous development of mobile networks, managing and optimizing user mobility between different network nodes has become crucial. Modern mobile communication systems require seamless connectivity between various network nodes to ensure efficient and reliable handovers. In order to ensure the communication continuousness in the wireless communication system, multiple technologies are proposed, such as cell switch. During the cell switch, the terminal device may switch among different cells. Further, technology of layer 1 / layer 2 (L1 / L2) triggered mobility (LTM) may be used for enabling the cell switch. LTM is a procedure in which the next generation node B (gNB) receives LI and / or layer 3 (L3) measurement report(s) from a UE, and thus the gNB changes user equipment (UE) serving cell by a cell switch command signalled via a medium access control (MAC) control element (CE).SUMMARY

[0003] In a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from a second apparatus, a mobility configuration at least comprising a configuration of channel state information reference signals, CSLRSs, for a CSI acquisition of at least one candidate cell; receive a cell switch command indicating the atleast one candidate cell as a target cell; and determine, based on at least a reference point determined by a timing of a reception of the cell switch command, a timeline for at least one of a CSI report carrying the information related to CSI acquisition to the target cell or a CSI reference resource.

[0004] In a second aspect of the present disclosure, there is provided a method. The method comprises: receiving, from a second apparatus, a mobility configuration at least comprising a configuration of channel state information reference signals, CSI-RSs, for a CSI acquisition of at least one candidate cell; receiving a cell switch command indicating the at least one candidate cell as a target cell; and determining, based on at least a reference point determined by a timing of a reception of the cell switch command, a timeline for at least one of a CSI report carrying the information related to CSI acquisition to the target cell or a CSI reference resource.

[0005] In a third aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for receiving, from a second apparatus, a mobility configuration at least comprising a configuration of channel state information reference signals, CSI-RSs, for a CSI acquisition of at least one candidate cell; means for receiving a cell switch command indicating the at least one candidate cell as a target cell; and means for determining, based on at least a reference point determined by a timing of a reception of the cell switch command, a timeline for at least one of a CSI report carrying the information related to CSI acquisition to the target cell or a CSI reference resource.

[0006] In a fourth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the fourth aspect.

[0007] It is to be understood that the Summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0009] FIG. 1A and FIG. IB illustrate example communication environments in which example embodiments of the present disclosure can be implemented, respectively

[0010] FIG. 2 illustrates procedures for CSI acquisition before / during LTM cell switch;

[0011] FIG. 3 A illustrates a signaling flow for an overall procedure for LTM;

[0012] FIG. 3B illustrates an example of aperiodic reporting using periodic RSs in accordance with some example embodiments of the present disclosure;

[0013] FIG. 4A illustrates a signaling chart of communication according to some example embodiments of the present disclosure;

[0014] FIG. 4B illustrates a signaling chart of communication according to some example embodiments of the present disclosure;

[0015] FIG. 5 illustrates an example showing CSI reference resource(s) based on slot (N) for CSI acquisition measurements in accordance with some example embodiments of the present disclosure;

[0016] FIG. 6 illustrates an example diagram related to CSI reporting timeline for candidate cell CSI acquisition using the CSC as the reference in accordance with some example embodiments of the present disclosure;

[0017] FIG. 7 illustrates an example diagram related to CSI reporting timeline for candidate cell CSI acquisition using the CSC as the reference in accordance with some example embodiments of the present disclosure;

[0018] FIG. 8 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0019] FIG. 9 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0020] FIG. 10 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0021] FIG. 11 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0022] FIG. 12 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0023] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0024] Principle of the present disclosure will now 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 limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0025] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0026] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases 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 it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0027] It shall be understood that although the terms “first,” “second,”..., etc. in front of noun(s) and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another and they do not limit the order of the noun(s). 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.

[0028] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the listof 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.

[0029] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0030] The terminology used herein is for the purpose of describing particular embodiments only 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 the presence 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.

[0031] As used in this application, the term “circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable):(i) a combination of analog and / or digital hardware circuit(s) with software / firmware and(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0032] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the termcircuitry 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.

[0033] As used herein, the term “communication network” refers to a network following any suitable 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), 5.5G, the sixth generation (6G) communication protocols, and / or any other protocols either currently known or to be developed in 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.

[0034] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to 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 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-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous 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 comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaveslike 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.

[0035] The term “terminal device” refers to any end device that may be capable of wireless communication. 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 Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital 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 other wearable, 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 wireless devices 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, and the like. The terminal 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 “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0036] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, 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 combination of the time, frequency, space and / or code domain 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.

[0037] Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0038] FIG. 1 A shows an example communication environment 100A in which example embodiments of the present disclosure may be implemented. The network communication 100 A includes a first apparatus 110, a second apparatus 120 and a third apparatuses 130.

[0039] In some example embodiments, the first apparatus 110 may be comprised in a terminal device / apparatus and the second apparatus 120 / third apparatus 130 may be comprised in a network device / apparatus. Additionally, the second apparatuses 120 and the third apparatus 130 may provide one or more coverage areas, also called as cells. As illustrated in FIG. 1A, the communication environment 100A includes a cell 150 provided by the second apparatus 120 and a cell 160 provided by the third apparatus 130.

[0040] Further, in some example embodiments, the radio access network (RAN) architecture may include a centralized part, or central unit (CU), and a distributed part, or distributed unit (DU). The CU and the DU may be connected to one another by a so-called Fl interface. In the example of FIG. 1A, the second apparatus 120 may refer to a base station (such as, the next generation node B, gNB), a gNB-CU and / or a gNB-DU. Similarly, the third apparatus 130 also may refer to a base station (such as, a gNB), a gNB CU and / or a gNB DU.

[0041] In the example of FIG. 1A, the first apparatus 110 may move over time. As illustrated in FIG. 1A, the first apparatus 110 locates at different positions at different time points (T1 and T2). As moving, the first apparatus 110 may switch among different cells, i.e., a cell switch procedure. In the example of FIG. 1 A, the first apparatus 110 may switch from cell 150 to cell 160. For a better discussion, the cell 150 may be called as the first cell 150, the source cell 150 or the serving cell 150, and the cell 160 may be called as the second cell 160, the candidate cell 160. Further, in a case that the cell 160 is selected as a target cell, the cell 160 also may be called as the target cell 160.

[0042] Reference is now made to FIG. IB, which illustrates other example communication environments 100B in which example embodiments of the present disclosure may be implemented. In the example (A) of FIG. IB, the second apparatus 120 and the third apparatus 130 are gNB DUs, and both the second apparatus 120 and the third apparatus 130 are connected to a same gNB-CU. In the example (B) of FIG. IB, the second apparatus 120 and the third apparatus 130 are gNB DUs, while the second apparatus 120the third apparatus 130 are connected to two different gNB-CUs.

[0043] It should be noted examples (A) and (B) of FIG. IB are two example communication environments of the present discourse which are illustrated only for the purpose of illustration without suggesting any limitations. In fact, the cell switch discussed herein may include at least one of the following: an inter-gNB cell switch, an intra-CU cell switch, or an inter-CU cell switch.

[0044] It is to be understood that the number of devices and their connections shown in FIG. 1A and FIG. IB are only for the purpose of illustration without suggesting any limitation. The communication environments 100 A and 100B may include any suitable number of devices configured to implementing example embodiments of the present disclosure. Although not shown, it would be appreciated that one or more additional devices may be located in the cell, and one or more additional cells may be deployed in the communication environments 100 A and 100B. It is noted that although illustrated as a network device, the second apparatus 120 / the third apparatus 130 may be another device than a network device. Although illustrated as a terminal device, the first apparatus 110 may be another device than a terminal apparatus.

[0045] Communications in the communication environments 100A and 100B may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), 5.5G, the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0046] Some discussed schemes relate to mobility enhancements, i.e., enhancements to Layer 1 / 2 triggered mobility (LTM) with CSLRS measurements where enabling CSIacquisition (e.g., acquiring the channel information such as one or more of, a channel quality indicator (CQI), a rank indicator (RI), a precoding matric indicator (PMI), etc.) on candidate cell(s) based on CSI-RS is one of the objectives. With this, the UE would be able to acquire and report the CSI parameters (CQI, PMI, RI, or / and LI) for a candidate cell, which then can be used for the transmission / reception in the target cell after the cell switch. This would reduce the need of additional measurements for CSI acquisition in the target cell for initial transmissions / receptions.

[0047] Some related mobility enhancements are shown in the following:• Measurements related enhancements for purpose of supporting LTM:o Measurement related enhancements are applicable to Intra-Central Unit Master Cell Group (Intra-CU MCG) / Secondary Cell Group (SCG) LTM and Inter-CU MCG / SCG LTMo Specify necessary components to support event triggered LI measurement reportingo Specify support for CSI-RS measurements for LTM procedures and enable CSI- RS based beam managemento Specify CSI acquisition on candidate cell(s) based on CSI-RS before or during LTM cell switchNOTE: RANI Work Group (WG) to decide on whether to support CSI report before or during the LTM cell switch, as part of the CSI acquisition procedure.

[0048] In some discussions, three alternatives were studied on the timeline of the CSI acquisition related measurements and reporting, which are shown in the following:• Alternative-1 : CSI-RS measurement and CSI reporting operations are performed before reception of LTM Cell Switch Command (CSC) MAC CE.o The report is sent to the serving cell and transferred to the candidate / target cell(s) • Alternative-2: CSI-RS measurement can start before reception of LTM CSC MAC CE and CSI reporting operation is performed after reception of LTM CSC MAC CE.o The report is sent directly to target cell• Alternative-3: CSI-RS measurement and CSI reporting operations are performed after reception of LTM CSC MAC CE.

[0049] During some discussion, it was agreed to proceed with only alternatives 2 and 3 from the above, more specifically: As baseline, CSI-RS measurement and CSI reporting operations are performed after reception of LTM CSC MAC CE.

[0050] Reference is now made to FIG. 2, which shows procedures for CSI acquisitionbefore / during LTM cell switch.

[0051] The procedure is shown in the following in connection with FIG. 2:• The report is sent directly to target cell• Introduce UE capability for CSI-RS measurement can start before reception of LTM CSC MAC CEo Other than UE capability, strive for no additional spec impact compared to the baseline (only one triggering mechanism will be specified)

[0052] LTM is a cell switch procedure, where UE’s serving cell (Primary Cell (PCell) or Primary Secondary Cell (PSCell)) is switched by the network by sending an LTM cell switch command. An LTM switch command is currently assumed delivered by MAC signaling using a 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 based on measurements (for example LI measurements) that are performed and reported (for example LI measurement report) by the UE. Measurements and reporting are based on LTM candidate cell configuration provided by the network for one or more LTM candidate cells. An LTM candidate cell may be neighboring cells or a UE’ s current serving cells (e.g. one of the current secondary cell).

[0053] In some discussed schemes, LTM measurements on a neighboring candidate cell are performed using SSBs transmitted by the candidate cell for which the SSB configuration is provided to the UE.

[0054] Before the cell switch, the network may optionally activate one or more TCI state(s) for one or more candidate cells for early Downlink (DL) synchronization. Once a candidate cell TCI state is activated the UE may start tracking the downlink time / frequency synchronization using the reference signals associated with the activated TCI state(s). The UE may also perform early Uplink (UL) synchronization before the cell switch if this is requested by the network.

[0055] Reference is now made to FIG. 3A, which shows a signaling chart 300 for the LTM procedure. Specifically, FIG. 3A shows a scenario of Intra-CU LTM handover between UE 302 and gNB 304.

[0056] Firstly, at block 305, the UE 302 may be in an RRC_CONNECTED mode, meaning that the UE 302 is connected to the gNB 304. Then, the UE 302 may send (310) a MeasurementReport message to the gNB 304. The gNB 304 may decide to configure LTM and initiate LTM preparation. At block 315, the gNB 304 may perform the LTM candidate preparation.

[0057] After performing the LTM candidate preparation, the gNB 304 may transmit (320) an RRCReconfiguration message to the UE 302 including the LTM candidate configurations. The UE 302 may store the LTM candidate configurations and transmit (325) an RRCReconfigurationComplete message to the gNB 304. The UE 302 may perform the DL synchronization with the candidate cell(s) (via early TCI activation) before receiving the cell switch command.

[0058] The UE 302 may, at step 330 and 335, perform early Timing Advance (TA) acquisition with the candidate cell(s) as requested by the network (i.e., gNB 304) before receiving the cell switch command. This is done via Contention-Free Random Access (CFRA) triggered by a Physical Downlink Control Channel (PDCCH) order from the source cell, following which the UE 302 sends preamble towards the indicated candidate cell.

[0059] At this step, in order to minimize the data interruption of the source cell due to CFRA towards the candidate cell(s), the UE 302 may not receive random access response from the network for the purpose of TA value acquisition and the TA value of the candidate cell is indicated in the cell switch command. The UE 302 may not maintain the TA timer for the candidate cell and relies on network implementation to guarantee the TA validity.

[0060] The UE 302 may perform LI measurements on the configured candidate cell(s) and transmit (340) LI measurement reports to the gNB 304. LI measurement should be performed as long as RRC reconfiguration (at step 320) is applicable.

[0061] The gNB 304 may, at block 345, decide to execute cell switch to a target cell. Then the gNB 304 may transmit (350) a cell switch command MAC CE triggering cell switch by including the candidate configuration index of the target cell. The UE 302, at block 355, may switch to the target cell and apply the configuration indicated by candidate configuration index.

[0062] The UE 302 may perform (360) the random-access procedure towards the target cell, if UE 302 does not have valid TA of the target cell. Finally, the UE 302 may complete (365) the LTM cell switch procedure by sending RRCReconfigurationComplete message to target cell. For RACH-based LTM, if the UE 302 has performed a RA procedure in step 360, the UE 302 may consider that LTM cell switch execution is successfully completed when the random-access procedure is successfully completed. For RACH-less LTM, the UE 302 may consider that LTM cell switch execution is successfully completed when the UE 302 determines that the network has successfully received its first UL data.

[0063] The steps 330-365 can be performed multiple times for subsequent LTM using the LTM candidate configuration(s) provided in step 320. The procedure over the air interface described with reference to FIG. 3A is applicable to both intra-gNodeB-Distributed Unit Ll / 2 triggered mobility (intra-gNB-DU LTM) and inter-gNodeB-Distributed Unit Ll / 2 triggered mobility (inter-gNB-DU LTM). The overall LTM procedures over Fl-C interface are captured in some discussed schemes.

[0064] Regarding the CSI reference resource, the CSI reference resource for a serving cell, i.e., for measurements which are reported to the serving cell using LI measurement reporting of type periodic, semi-persistent (SP), or aperiodic, may be defined as shown in the following:In the frequency domain, the CSI reference resource may be defined by the group of downlink physical resource blocks corresponding to the band to which the derived CSI relates.- In the time domain, the CSI reference resource for a CSI reporting in uplink slot n' may be defined by a single downlink slot nis a parameter configured by higher layer as specified in clause 4.2 of [6 TS 38.213], and where fiKoffsetis the subcarrier spacing configuration for K0^setwith a value of 0 for frequency range 1,are thesubcarrier spacing configurations for DL and UL, respectively, andffsetand / / offsetare determined by higher-layer configured ca-SlotOffset for the cells transmitting the uplink and downlink- where for periodic and semi-persistent CSI reporting- if a single CSI-RS / SSB resource is configured for channel measurement nCSI ref is the smallest value greater than or equal to 4 • 2kDL, such that it corresponds to a valid downlink slot, or- if multiple CSI-RS / SSB resources are configured for channel measurement nCSI ref is the smallest value greater than or equal to 5 • 2^DL, such that it corresponds to a valid downlink slot.- where for aperiodic CSI reporting, if the UE is indicated by the Downlink Control Information (DCI) to report CSI in the same slot as the CSI request, nCSI ref is such that the reference resource is in the same valid downlink slot as the corresponding CSI request, otherwise nCSI ref is the smallest value greater than or equal to [Z / Nsymb\’ such that slot n- nCSI ref corresponds to a valid downlink slot, where Z' corresponds to the delay requirement in some discussed schemes.- when periodic or semi-persistent CSI-RS / CSI Interference Measurement (CSI-IM) or SSB is used for channel / interference measurements, the UE is not expected to measure channel / interference on the CSI-RS / CSI-IM / SSB whose last OFDM symbol is received up to Z' symbols before transmission time of the first OFDM symbol of the aperiodic CSI reporting.

[0065] A slot in a serving cell shall be considered to be a valid downlink slot if certain conditions are met, wherein the conditions mentioned herein are shown in the following: Conditions:- it comprises at least one higher layer configured downlink or flexible symbol, and - it does not fall within a configured measurement gap for that UE

[0066] If there is no valid downlink slot for the CSI reference resource corresponding to a CSI Report Setting in a serving cell, CSI reporting is omitted for the serving cell in uplink slot n'.

[0067] For a CSI report with reportQuantity not set to ‘ ssb-Index-RSRP\ ‘ ssb-Index-SINR' , ‘ s sb -Index-RSRP -Index' or "ssb- Index-SINR-Index' , after the CSI report (re)configuration, serving cell activation, Bandwidth Part (BWP) change, or activation ofSemi-Persistent CSI (SP-CSI), the UE reports a CSI report only after receiving at least one CSI-RS transmission occasion for channel measurement and CSI-RS and / or CSI-IM occasion for interference measurement no later than CSI reference resource and drops the report otherwise.

[0068] For a CSI report configuration containing a list of sub -configurations provided by csi-ReportSubConfigToAddModList, after the CSI report (re)configuration, serving cell activation, BWP change, or activation of Semi-Persistent CSI (SP-CSI), the UE reports a CSI report including one or more sub-reports only after receiving at least one CSI-RS transmission occasion for channel measurement and CSI-RS and / or CSI-IM occasion for interference measurement, per sub-configuration, no later than CSI reference resource and drops the report otherwise, where the sub-configuration is the activated / triggered one for Aperiodic / Semi-Persistent CSI (AP / SP-CSI) reporting, or the configured one for Periodic CSI (P-CSI) reporting.

[0069] Regarding the Ll-RSRP reporting, if the higher layer parameter timeRestrictionForChannelMeasurements in CSI-ReportConfig s set to "notConfigured" , the UE shall derive the channel measurements for computing Ll-RSRP value reported in uplink slot n based on only the SS / PBCH or NZP CSI-RS, no later than the CSI reference resource, associated with the CSI resource setting.

[0070] If the higher layer parameter timeRestrictionForChannelMeasurements in CSI-ReportConfig is set to "Configured" , the UE shall derive the channel measurements for computing Ll-RSRP reported in uplink slot n based on only the most recent, no later than the CSI reference resource, occasion of SS / PBCH or Non-Zero Power CSI-RS (NZP CSI-RS) associated with the CSI resource setting.

[0071] Regarding the CSI computation time in Network Resource (NR), when the CSI request field on a DCI triggers a CSI report(s) on PUSCH, the UE shall provide a valid CSI report for the / / -th triggered report, which is shown in the following:- if the first uplink symbol to carry the corresponding CSI report(s) including the effect of the timing advance, starts no earlier than at symbol Zre / , andif the first uplink symbol to carry the / / -th CSI report including the effect of the timing advance, starts no earlier than at symbol Z'refin),where Zre / may be defined as the next uplink symbol with its CP starting Tproc CSI= (Z)(2048 + 144) • K2~^ ■ Tc+ Tswitchafter the end of the last symbol of the PDCCH triggering the CSI report(s), and where Z'rej(n), may be defined as the next uplink symbol with its CP starting T'proc CSI= ^7^(2048 + 144) • K2~^ ■ Tcafter the end of the last symbol in time of the latest of aperiodic CSI-RS resource for channel measurements, aperiodic CSI-IM used for interference measurements, and aperiodic Non-zero Power (NZP) CSI-RS for interference measurement for a CSI-ReportConfig, or for all triggered subconfigurations if CSI-ReportConfig contains multiple sub-configurations, when aperiodic CSI-RS is used for channel measurement for the / / -th triggered CSI report, and where TSWitch may be defined in some discussed schemes and is applied only if Zxof table 1 is applied.

[0072] When the CSI request field on a DCI triggers a CSI report(s) on PUSCH, if the first uplink symbol to carry the corresponding CSI report(s) including the effect of the timing advance, starts earlier than at symbol Zref, which is shown in the following:the UE may ignore the scheduling DCI if no HARQ-ACK or transport block is multiplexed on the PUSCH.

[0073] When the CSI request field on a DCI triggers a CSI report(s) on PUSCH, if the first uplink symbol to carry the / / -th CSI report including the effect of the timing advance, starts earlier than at symbol Z'rej(n), which is shown in the following:- the UE may ignore the scheduling DCI if the number of triggered reports is one and no HARQ-ACK or transport block is multiplexed on the PUSCH- Otherwise, the UE is not required to update the CSI for the / / -th triggered CSI report.

[0074] Z, Z' and p are defined as:

[0075] Z = max (Z(m)) and Z' = max (Z'(m)), where M is the number of m=0,...,M-l m=0,...,M-lupdated CSI report(s), (Z(m),Z'(m)) corresponds to the / / / -th updated CSI report and may be defined as the following:<

[0076] Table 1: 6 7 computation delay requirement 1

[0077] Table 2: CSI computation delay requirement 2

[0078] One of the motivations of LTM is to maintain high data transmission efficiency (or spectral efficiency) in the process of fast cell switch. To achieve this, (early) CSI acquisition based on CSI-RS(s) for the candidate cells using the measurements on CSI-RS(s) transmitted by the candidate cells has been agreed as one of the objectives for LTM to be specified. With this, the UE would be able to acquire and report the CSI parameters (CQI, PMI, RI, or / and LI) for a candidate cell, which then can be used for the transmission / reception in the target cell after the cell switch. This would reduce the need of additional measurements for CSI acquisition in the target cell for initial transmissions / receptions.

[0079] In the context of the present disclosure, term of CSLrelated information acquisition, CSI acquisition, and similar terms are used interchangeably which refers to for the UE to measure, measure and store, or acquire CSI related information such as one or more of CQI, RI, PMI, RSRP, CRI.

[0080] For Layer 1 measurement reporting, the CSI reference resource may be defined to determine (valid) measurement (RS) occasions (i.e., RSs occurring no later than the DL slot overlapping with the CSI reference resource) for reporting purposes. Based on this,the UE may decide whether to omit a report depending on the position of the measurement RS occasion(s) relative to the CSI reference resource. The CSI reference resource may take into account the minimum UE capability for CSI computation and also may mitigate the issues of outdated CSI. The CSI reference resource also serves as the reference slot for deriving parameters for CQI (and, in some cases, PMI and RI). In certain scenarios, such as periodic and semi-persistent periodic (SP periodic) reporting, the CSI reference resource helps to determine the reference timing for the CSI processing unit occupancy associated with the report.

[0081] Reference is now made to FIG. 3B, which shows an example of aperiodic reporting using periodic RSs.

[0082] For the periodic / SP / Aperiodic reporting for the serving cell where the measurements are reported to the serving cell, the CSI reference resource is determined with respect the uplink reporting slot timing. In the case of aperiodic reporting triggered by a DCI, the uplink reporting slot timing is also used to evaluate whether the UE has enough time to process the DCI and prepare the corresponding report. An example of valid CSI reference resource and CSI reporting timeline for an aperiodic reporting triggered by DCI using periodic CSI-RSs is shown in FIG. 3B, where the details are already provided above.

[0083] For CSI acquisition for a candidate cell during a cell switch procedure (LTM), when a report is sent directly to the target cell after the reception of the cell switch command, the timing of the uplink slot containing the report cannot be determined at the time of measurements. If the UE performs measurements prior to the reception of the cell switch command, the timing of the cell switch command itself may not even be known, making it difficult to determine the timing of the reporting slot. Even when the UE performs measurements after the reception of the cell switch command, the exact timing of the reporting slot remains indeterminate due to various factors, e.g., the type of cell switch (e.g., Random Access Channel (RACH)-less vs. RACH-based), occurrence of an uplink slot relative to the handover interruption delay, which itself depends on early procedures such as early DL / UL synchronization and the processing of the RRC configuration, etc.

[0084] As a result, the determination of the timeline for the CSI reference resource becomes unclear in such scenarios. Without the CSI reference resource, it may not clearwhich measurement occasions to be measured for a potential upcoming reporting which may either increase CPU usage at the UE side (when the UE keeps making measurements for all the occasions) or may increase the risk of outdated measurement. How to address the problem of determining the timeline for the CSI reference resource for CSI acquisition for candidate cell(s) is a focus of attention.

[0085] In accordance with some example embodiments of the present disclosure, there is provided a solution for CSI reference resource for CSI acquisition measurement for a mobility candidate cell. In this solution, the first apparatus 110 receives, from a second apparatus 120, a mobility configuration at least comprising a configuration of CSI-RSs for CSI acquisition of at least one candidate cell. The first apparatus 110 determines a reference slot (which may also be referred as a reference uplink slot herein), to be used for CSI acquisition of the at least one candidate cell, based at least on a first reference point at least partially related to a reception of the mobility configuration or a control command. The first apparatus 110 determines channel measurements for CSI acquisition of the at least one candidate cell based on one or more measurement occasions determined relative to the reference slot.

[0086] In this way, the CSI reference resource for CSI reporting to the target cell can be defined for both scenarios: measurements performed before and after the reception of the cell switch command. Furthermore, valid measurement RS occasions and valid CSI reporting can be defined to support CSI acquisition for a candidate cell in both scenarios: measurements performed before and after the reception of the cell switch command.

[0087] In the present disclosure, a solution to derive the CSI reference resource and / or valid CSI reporting timeline by introducing the concept of (virtual) uplink reference slots for CSI acquisition measurements and reporting for mobility candidate cells is proposed. These uplink reference slots (or may also be referred as reference slots or virtual slots or virtual uplink reference slots or virtual uplink slots) may be used at the reference for the calculation of CSI reference resource (and other purpose, e.g., CSI processing unit occupancy) for a potential upcoming reporting slot until the UE sends the information about the report. The proposed solution includes the following key aspects:-Definition of Uplink Reference Slots: Uplink reference slots are defined relative to a known timeline, which may include a reference slot associated with reception of a Handover (HO) o mobility or cell switch configuration, a control command that activatesmeasurements, the most recent virtual uplink slot, or a cell switch command (CSC), and a minimum time gap, accounting for first apparatus’s minimum CSI processing and delay time requirements. Multiple options are proposed for configuring the timeline, such as subcarrier spacing (SCS), slot / frame timing, and other related parameters.-CSI Reference Time for Virtual Uplink Reference Slots: CSI reference time is determined with respect to each virtual uplink reference slot. The first apparatus 110 may derive valid measurement occasions for a potential upcoming reporting slot that may occur on or after the next determined virtual uplink reference slot.-Sharing Information on Reference Slots: It is proposed to share the information about the virtual uplink reference slot used to determine the latest uplink reference slot. This ensures that both the target cell and the first apparatus 110 have a common understanding of the timeline with respect to the CSI reference resource, specially in the scenarios where some ambiguity may arise.

[0088] Additionally, a specific example of the general framework is provided. This example uses the cell switch command as the reference slot and the minimum latency requirements.

[0089] The proposed solutions are applicable to both scenarios: When the first apparatus 110 starts measurements before the reception of the cell switch command, and when the UE starts measurements only or continues measurements after the reception of the cell switch command.

[0090] The reporting slot herein refers to uplink slot (or the actual uplink slot) in the target cell where the first apparatus 110 sends the information regarding the report (e.g., the report containing the measurements like CQI, PMI, RI, etc., or an indication that the first apparatus 110 has acquired CSI for the target cell). For example, this may be a slot where the first apparatus 110 sends a specific uplink message to the target cell in, e.g., the message containing the RRC Reconfiguration Complete message, which may be a configured grant or a dynamic grant based first uplink message in a RACH-less cell switch or a message 3 sent during the RACH procedure in a RACH-based cell switch. In some examples, the UE may be provided a dynamic uplink grant to send the CSI report

[0091] Reference is now made to FIG. 4 A, which shows a signaling chart 400A for communication according to some example embodiments of the present disclosure. Asshown in FIG. 4 A, the signaling chart 400 involves a first apparatus 110, a second apparatus 120 and a third apparatus 130. For the purpose of discussion, reference is made to FIG. 1 to describe the signaling chart 400A.

[0092] FIG. 4A shows an example of signaling flow showing the timeline of CSI reference determination, measurements based on the valid RS occasions determined based on the CSI reference resource, and the reporting. In FIG. 4 A, a scenario when the first apparatus 110 supports and starts making measurements before the reception of the CSC is illustrated.

[0093] As shown in FIG. 4 A, the first apparatus 110 may send (405) capability information indicating a support to perform measurements for the CSI acquisition for the at least one candidate cell before the reception of the cell switch command.

[0094] For example, the capability information may comprise information related to a capability of the first apparatus 110 for CSI acquisition for at least one candidate cell, such as, information related to a minimum time gap (e.g., time gap X) and / or information of whether the first apparatus 110 can make measurement before a reception of a cell switch command (CSC).

[0095] The first apparatus 110 may transmit (410) the L3 measurement report to the second apparatus 120 (for example, to the source DU of the second apparatus 120). The source DU of the second apparatus 120 may transfer (415) the L3 measurement report to the source CU via an UL RRC message. Based on the measurement report, the second apparatus 120 may perform (420) the LTM candidate preparation.

[0096] The second apparatus 120 may generate (425) a mobility configuration, for example, an LTM configuration or a HO / LTM configuration, comprising a configuration of CSLRSs for CSI acquisition of at least one candidate cell which may at least comprise a configuration of CSLRSs for CSI acquisition of at least one candidate cell.

[0097] For example, the mobility configuration may optionally comprise reference configuration for subcarrier spacing (SCS) and the timing to be used (along with corresponding parameters) to determine a reference slot (for example, the slot n), the time gap (for example, the time gap X) and configuration related to the minimum time gap X.

[0098] In some embodiments, the mobility configuration is a radio resource control signaling comprising LTM configuration or handover-related configuration.

[0099] As shown in FIG. 4 A, the second apparatus 120 may transmit (430) the mobility configuration to the first apparatus 110, for example, via an RRC reconfiguration message.

[0100] Upon receiving the RRC reconfiguration message, the first apparatus 110 may transmit (435) a RRC reconfiguration complete message to the second apparatus 120.

[0101] As shown in FIG. 4 A, the first apparatus 110 may (440) determine a reference slot, to be used for CSI acquisition of the at least one candidate cell, based at least on a first reference point at least partially related to a reception of the mobility configuration or a control command.

[0102] In some embodiments, the first apparatus 110 may determine the reference slot based on a first reference point and a time gap.

[0103] For example, for a CSI reporting for a (mobility) candidate cell, the first apparatus 110 may determine a reference slot, e.g., a reference uplink slot denoted as slot N. The slotN may be determined based on a first reference point, e.g., denoted as slot (n), which may be associated with or specific to the CSI report and a (minimum) time gap, e.g., denoted as X. The slot N may be determined by a slot = slot (n) + X.

[0104] In some embodiments, the reference slot may start after a time gap after the end of the first reference point.

[0105] The first reference point may be defined associated with the mobility configuration, for example, an LTM configuration or a HO / LTM configuration.

[0106] In some embodiments, the first reference point may be defined based on a downlink slot containing either a control channel scheduling a data channel or a data channel carrying the information of the mobility configuration.

[0107] For example, as an option (i.e., the option 1), the slot (n) (i.e., the first reference point) may be defined based on the downlink slot containing either the control channel (PDCCH) scheduling the data channel (PDSCH) or the data channel (PDSCH) carrying the information of HO / LTM configuration (an RRC Reconfiguration).

[0108] In some embodiment, the HO / LTM configuration may contain the configuration information of CSI reporting and associated measurement RS(s).

[0109] In some embodiments, the first reference point may be defined based on an uplink slot carrying uplink information of an acknowledgement for a reception of themobility configuration. For example, in one option, the slot(n) (i.e., the first reference point) may be defined based on the uplink slot carrying the uplink information of acknowledgement for the reception of the HO / LTM configuration.

[0110] The first reference point may also be defined associated with a control command, for example, e.g., DCI in layer 1 or a MAC CE in layer 2.

[0111] In some embodiments, the first reference point may be defined based on a downlink slot where a control command containing information related to the at least one candidate cell is received. For example, in this option (i.e., option 2), slot (n) (i.e., the first reference point) may be defined based on the downlink slot where a control command containing the information related to a mobility candidate cell is received.

[0112] In some embodiments, the control command may comprise a control command for activating CSI measurements associated with the CSI acquisition for the at least one candidate cell. In some other embodiments, the control command may comprise a command activating / triggering the CSI measurements associated with the CSI acquisition for the candidate cell.

[0113] In some embodiments, the control command may also comprise a control command for a candidate transmission configuration indicator (TCI) activation / deactivation command for activating / deactivating a TCI state associated with the at least one candidate cell or the CSI-RS to be measured for the CSI acquisition for the at least one candidate cell. For example, the control command may comprise a candidate TCI activation / deactivation command activating / deactivating a TCI state associated with the candidate cell. In some example embodiments, a TCI state may be associated with a CSI-RS when the TCI state contains a synchronization signal block (SSB) information which is quasi co-located (QCLed) with the CSI-RS.

[0114] It is also possible that the control command may comprise a physical downlink control channel (PDCCH) order triggering a random access channel (RACH) transmission towards the at least one candidate cell. For example, the control command may comprise a PDCCH order triggering an early Physical Random Access Channel (PRACH) transmission towards the candidate cell.

[0115] Additionally or optionally, the control command may comprise a physical downlink control channel, PDCCH, order triggering a random access channel, RACH,transmission associated with the CSI-RS to be measured for the CSI acquisition for the at least one candidate cell. In some example embodiments, a PDCCH order triggering a RACH transmission may be associated with a CSI-RS when the PDCCH order contains a synchronization signal block (SSB) which is quasi co-located (QCLed) with the CSI-RS.

[0116] In some embodiments, the first reference point the slot(n) may be defined based on an uplink slot carrying the uplink information of an acknowledgement for the reception of the control command.

[0117] As mentioned above, the reference slot may start after a time gap after the end of the first reference point. Therefore, the time gap may also need to be defined.

[0118] In some embodiments, the time gap may be defined as the smallest value greater than or equal to a time period, such that a location, starting after a time gap after the end of the first reference point, corresponds to a valid uplink slot. For example, the (minimum) time gap, e.g., denoted as X, may be defined as the smallest value greater than or equal to Y, such that slot (n)+Y, corresponds to a valid uplink slot (details below), wherein the value of Y (e.g., may be defined in terms of number of symbols, or slot or other time units such as milliseconds / seconds).

[0119] In some embodiments, time gap may be specified based on a capability of the first apparatus, or is configured by the mobility configuration, a configuration of CSI-RSs for CSI acquisition of the at least one candidate cell, or a CSI report configuration. For example, the time gap may be determined / specified based on the capability of the first apparatus 110 (e.g., UE capability associated with the CSI computation delay requirement associated with the CSI report). As another example, the time gap may be configured to the UE, e.g., as a part of the HO / LTM configuration or candidate cell CSI acquisition related configuration or CSI report configuration.

[0120] In some embodiments, the time gap may be defined based on a specific value or based on a CSI computation delay or based on a capability of the first apparatus 110.

[0121] In some embodiments, the first reference point and the time gap may be calculated using at least one configuration parameter based on a serving cell configuration. The serving cell is a serving cell of the first apparatus. More detail for the calculation of the first reference point and the time gap will be described as below.

[0122] In some embodiments, the configuration parameter (in the serving cellconfiguration and / or in the candidate cell configuration) may comprise sub-carrier spacing configuration associated with a downlink slot or channel or signal and / or sub-carrier spacing configuration associated with an uplink slot or channel or signal and / or timing of a downlink slot and / or timing of an uplink slot and / or slot format and / or timing of a frame or frame timing. In some embodiments, the configuration parameter may be configured by the mobility configuration.

[0123] As an option, the first reference point slot(n) and time gap X may be calculated using the serving cell (current serving cell or source cell) configuration, e.g., a configuration of SCS of the active DL / UL BWP, slot format, frame timing.

[0124] For example, the first reference point slot (n), when it is determined based on a downlink slot (as in option 1 and option 2 above), may be defined as Slot(n) = ceil or floor (downlink slot_servingCell x (2AUL_SCS_servingCell / 2ADL_SCS_servingCell)) wherein the downlink slot servingCell is the downlink slot in option 1 and option 2 and UL SCS servingCell and UL SCS servingCell are the SCS of active DL and UL BWPs in the current serving cell.

[0125] And, the time gap X, may be defined as X = Y x 2AUL_SCS_servingCell.

[0126] In some embodiments, the first reference point and the time gap are calculated using at least one configuration parameter based on a candidate cell configuration, and the candidate cell is a candidate cell for which the CSI acquisition is being performed.

[0127] As another option, the first reference point slot(n) and time gap X, may be calculated using the candidate cell configuration e.g., using configuration of SCS of the initial / default DL / UL BWP, slot format, frame timing (determined from the HO / LTM configuration associated with the candidate cell)

[0128] For example, the first reference point slot (n), when it is determined based on a downlink slot, may be defined as Slot(n) = ceil or floor (downlink slot candidateCell x (2AUL_SCS_candidateCell / 2ADL_SCS_candidateCell)) wherein the downlink slot candidateCell is derived based on the candidate cell configuration, for example, the first candidate cell downlink slot considering the candidate cell timing which overlaps (partially / fully) with or comes after the serving cell downlink slot (as in option 1 and option 2), or uplink slot (as in option 1 and option 2), derived using the serving cell timing.

[0129] Alternatively, the first reference point slot (n), when it is determined based onan uplink slot, may be an uplink slot which is derived based on the candidate cell configuration, for example, the first candidate cell uplink slot considering the candidate cell timing which overlaps (partially / fully) with or comes after the serving cell downlink slot (as in option 1 and option 2), or uplink slot (as in option 1 and option 2), derived using the serving cell timing.

[0130] And, the X, may be defined as X = Y x 2AUL_SCS_candidateCell.

[0131] It is to be understood that this option assumes that the first apparatus 100 is also having DL sync and UL sync for the candidate cell.

[0132] In some embodiments, the first reference point and the time gap are calculated using at least one configuration parameter based on both serving cell and candidate cell configurations.

[0133] As another option, the first reference point slot(n) and time gap X may be calculated using both the serving and candidate cell configuration

[0134] For example, the slot (n), when it is determined based on a downlink slot (as in option 1 and option 2), may be defined as Slot(n) = ceil or floor (downlink slot_candidateCell’ x (2AUL_SCS_candidateCell / 2ADL_SCS_candidateCell)) wherein the downlink slot candidateCell’ is derived by converting the serving cell downlink slot (as in option 1 and option 2), or serving cell uplink slot (as in in option 1 and option 2) to a downlink slot in the candidate cell, using the SCS difference, e.g., ceil / floor / ratio of candidate cell DL SCS and serving cell DL or UL SCS, or minimum or maximum of candidate cell DL SCS and serving cell DL or UL SCS.

[0135] Alternatively, the slot (n), when it is determined based on an uplink slot, may be an uplink slot which is derived by converting the serving cell downlink slot (as in option 1 and option 2), or serving cell uplink slot (as in option 1 and option 2) to an uplink slot in the candidate cell, using the SCS difference, e.g., ceil / floor / ratio of candidate cell UL SCS and serving cell DL or UL SCS, or minimum or maximum of candidate cell UL SCS and serving cell DL or UL SCS.

[0136] And, the X, may be defined as X = Y x 2AUL_SCS_candidateCell.

[0137] It should be noted that this option assumes that the first apparatus 110 is also having DL sync and UL sync for the candidate cell.

[0138] It should be noted that this option assumes that the serving and candidate cell follow the same slot / frame timings and are synchronized, e.g., this may be possible specially when the cells belong to the same distributed unit (DU).

[0139] In some embodiments, which option for the calculation of the first reference point and the time gap will be to be used may be defined / configured to the first apparatus 110. In some other embodiments, this may be configured per candidate cell or per CSI acquisition related configuration in the mobility configuration.

[0140] Upon determining the reference (uplink) slot, e.g., denoted as slot (N), the first apparatus 110 may determine channel measurements for CSI acquisition of the at least one candidate cell based on one or more measurement occasions determined relative to the reference slot. Based on the determined channel measurements, the first apparatus 110 may perform (445) measurements and acquire CSI.

[0141] For example, for a CSI report for a (mobility) candidate cell, the first apparatus 110 may derive the channel measurements based on the measurements occasion(s) determined relative to a (reference uplink) slot N.

[0142] In some embodiments, the one or more measurement occasions are no later than a CSI reference resource associated with the reference slot that is the most recently determined.

[0143] In one option, for a CSI report for a (mobility) candidate cell, the first apparatus 110 may use the channel measurements based on the measurements occasion(s) no later than the CSI reference resource associated with the most recent determined (reference uplink) slot N (i.e., the reference slot).

[0144] The reference slot, that is the most recently determined, is with respect to a slot, which may be an uplink slot carrying a CSI report containing the information of CSI acquisition to a candidate cell after a reception of a cell switch command indicating a cell switch to the candidate cell.

[0145] For example, the most recent determined (reference uplink) slotN is with respect to the report slot. The report slot may be defined or provided to the first apparatus 110, e.g., an uplink slot carrying the information of RRCreconfigurationcomplete after the reception of the cell switch command.

[0146] For example, the first apparatus 110 may perform measurements for the CSI acquisition for the at least one candidate cell before the reception of the cell switch command.

[0147] As shown in FIG. 4A, the first apparatus 110 may determine (450) at least one subsequent reference slot after the first (or the first instance of the) reference slot.

[0148] Based on the determined reference slot which may be considered as the initial (reference uplink) slotN, in some embodiments, the at least one subsequent reference slot after the first reference slot may be defined using the most recently determined reference slot as the first reference point. For example, in one option (e.g., denoted as option 4), slot (n) may be defined based on the most recently (latest) determined (reference uplink) slot N associated with the CSI report.

[0149] Alternatively, at least one subsequent reference slot after the first reference slot may be defined using the most recently determined CSI reference resource calculated based on the most recently determined reference slot as the first reference point. For example, in an option, slot(n) may be defined based on the most recently (latest) determined CSI reference resource, e.g., CSI reference resource calculated based on the latest determined (reference uplink) slot N.

[0150] Therefore, those determined (reference uplink) slot N may be considered to determine the new slot (n) for the next (reference uplink) slot N calculation (e.g., for second, third, and so on, (reference uplink) slots).

[0151] As shown in FIG. 4A, the first apparatus 110 may perform (455) measurements determined based on the at least one subsequent reference slot after the first reference slot and acquire the CSI.

[0152] In some embodiments, for a CSI reporting for a (mobility) candidate cell, for a determined (reference uplink) slot N, the first apparatus 110 may determine a CSI reference resource (in the time domain) based on the determined (reference uplink) slot N and a time gap (ncsi_ref). That is, the first apparatus 110 may determine the CSI reference resource based on the determined reference slot and a time gap.

[0153] The nCSI ref may be defined using one existing rules given above, e.g., smallest value greater than or equal to 4 • 2lDLor 5 • 2^DLor based on the CSI computation delay such as smallest value greater than or equal to [z' / N^bor a new time gap may be definedfor this purpose. Depending on the options, the same SCS configuration used to determine the value of slot(n) and X as described above with different options may be used to determine the ncsi_ref.

[0154] Reference is now made to FIG. 5, which shows CSI reference resource(s) based on slot (N) for CSI acquisition measurements, where the first slot (N) is determined based on the DL slot containing the control command activating the CSI acquisition measurements, and then following reference slots are determined based on the most recent slot (N). The CSI reference resource is determined based on each reference slot (N), based on which the measurements occasions are determined for a reporting slot associated with the slot (N).

[0155] Upon performing measurements for CSI acquisition, in response to receiving (460) the cell switch command indicating a candidate cell as the target cell for a cell switch, the first apparatus 110 may generate the CSI report.

[0156] As shown in FIG. 4A, optionally, the first apparatus 110 may repeat (465) the above procedure if the reporting is not finished.

[0157] Then the first apparatus 110 may transmit (470), to the target cell, the CSI report generated based on the measurements determined based on the reference slot that is the most recently determined, wherein the CSI report includes information of acquired CSI related to one or more measurement quantities for the target cell.

[0158] In some embodiments, the measurement quantity comprises at least one of the following: an RI, a PMI, a CQI, a CRI, a LI, or a Ll-RSRP.

[0159] For example, the CSI report may contain the information of acquired CSI for the candidate cell, in terms of at least one of the measurement quantities: CQI, RI, PMI, CRI, etc. The configuration of the CSI report and associated measurement RSs may be given in the Handover (HO) or LTM configuration.

[0160] In some embodiments, the CSI report is configured to be sent to the candidate cell after receiving the cell switch command indicating the candidate cell for cell switch.

[0161] In some embodiments, the first apparatus 110 may transmit, to the target cell, information about the reference slot, that is the most recently determined, for the CSI report.

[0162] In some embodiments, the information may be sent by a serving (source) cell of the first apparatus to the candidate cell such that the candidate cell derives the reference slot. When the source and the candidate cell belong to different DUs within the same gNB or CU, such information about the reference slot can be exchanged via their respective DUs and the CU, for example, the source DU (of the source cell) may send the information to the CU which then can forward the information the candidate DU (of the candidate cell). When the source and the candidate cell belong to different gNBs or CUs, such information about the reference slot can be exchanged via their respective CUs, for example, the source DU (of the source cell) may send the information to the source CU which then can forward the information to the CU of the candidate DU(of the candidate cell).

[0163] For example, for a CSI report sent to a candidate / target cell, the information about the reference slot can comprise of the most recently determined slot (N), such that the candidate cell may also derive the slot (N) similar way as the first apparatus 110.

[0164] In one option, the information may indicate the most recently determined slot (N), e.g., offset between slot (N) and the UL slot containing the information.

[0165] In one option, the information about the most recently determined slot (N) may be sent along with the report, e.g., it may be defined as a part of the report content.

[0166] In one option, the information about the most recently determined slot (N) may be sent by the serving cell (source cell) to the candidate cell such that the candidate cell may also derive the slot (N) in a similar way as the first apparatus 110.

[0167] Reference is now made to FIG. 4B, which shows a signaling chart 400B for communication according to some example embodiments of the present disclosure. As shown in FIG. 4B, the signaling chart 400 involves a first apparatus 110, a second apparatus 120 and a third apparatus 130. For the purpose of discussion, reference is made to FIG. 1 to describe the signaling chart 400B.

[0168] In FIG. 4B, actions 405-435 have been described with reference to FIG. 4A, which will not be repeated here.

[0169] In the scenario of FIG. 4B, upon receiving (475) the cell switch command indicating a candidate cell as the target cell for a cell switch, the first apparatus 110 may (480) determine a reference slot, to be used for CSI acquisition of the at least onecandidate cell, based at least on the cell switch command. This scenario can be applicable when the first apparatus 110 performs or starts to perform or continue to perform or is configured to perform measurements for CSI acquisition for the target cell after the reception of the cell switch command (or during the cell switch).

[0170] Similarly, the first apparatus 110 may determine (480) the reference slot based on a first reference point and a time gap.

[0171] For example, for a CSI reporting for a (mobility) candidate cell, the first apparatus 110 may determine a reference slot, e.g., a reference uplink slot denoted as slot N. The slotN may be determined based on a first reference point, e.g., denoted as slot (n), which may be associated with or specific to the CSI report and a (minimum) time gap, e.g., denoted as X. The slot N may be determined by a slot = slot (n) + X.

[0172] In some embodiments, the reference slot may start after a time gap after the end of the first reference point.

[0173] The first reference point may be defined associated with the cell switch command.

[0174] As an option (i.e., the option 3), the first reference point may be defined based on a downlink slot containing either a control channel scheduling the data channel carrying information of the cell switch command or a data channel carrying information of the cell switch command.

[0175] For example, the slot (n) (i.e., the first reference point) may be defined based on the downlink slot containing either the control channel (PDCCH) scheduling the data channel (PDSCH) or the data channel (PDSCH) carrying the information of cell switch command.

[0176] Alternatively, the slot (n) (i.e., the first reference point) may be defined based on the uplink slot carrying the uplink information of acknowledgement for the reception of the cell switch command.

[0177] Similarly, the first apparatus 110 may also need to define the time gap. various options for time gap determination have been described with reference to FIG. 4A, which will not be repeated here.

[0178] Furthermore, options for the calculation of the first reference point and the timegap, which have been described with reference to FIG. 4A, will also be used for the procedure shown in FIG. 4B.

[0179] Upon determining the reference (uplink) slot, e.g., denoted as slot (N), the first apparatus 110 may determine channel measurements for CSI acquisition of the at least one candidate cell based on one or more measurement occasions determined relative to the reference slot. Based on the determined channel measurements, the first apparatus 110 may perform (485) measurements and acquire CSI.

[0180] Additionally, the first apparatus 110 may determine at least one subsequent reference slot after the first reference slot and repeat (490) the measurements based on the at least one subsequent reference slot after the first reference slot and acquire CSI. The determination of the at least one subsequent reference slot after the first reference slot has been with reference to FIG. 4A, which will not be repeated here.

[0181] It is to be understood that which option to be used for the determination of slot(n) (i.e., the first reference point) may be defined / configured to the first apparatus 110. Optionally, which option to be used for the determination of slot(n) (i.e., the first reference point) may be based on the capability of the first apparatus 110 of performing measurements for CSI acquisition before the reception of the cell switch command.

[0182] For example, if the first apparatus 110 is capable of performing measurements for CSI acquisition before the reception of the cell switch command, the first apparatus 110 may be configured with an option (from option 1 or 2) to determine slot(n) (i.e., the first reference point).

[0183] For example, if the UE is not capable of performing measurements for CSI acquisition before the reception of the cell switch command, the first apparatus 110 may determine slot(n) (i.e., the first reference point) associated with the reception of the cell switch command, e.g., the option 3.

[0184] Then the first apparatus 110 may transmit (495), to the target cell, the CSI report generated based on the measurements determined based on the reference slot that is the most recently determined, wherein the CSI report includes information of acquired CSI related to one or more measurement quantities for the target cell.

[0185] In some embodiments, the measurement quantity comprises at least one of the following: an RI, a PMI, a CQI, a CRI, a LI, or a Ll-RSRP.

[0186] For example, the CSI report may contain the information of acquired CSI for the candidate cell, in terms of at least one of the measurement quantities: CQI, RI, PMI, CRI, etc. The configuration of the CSI report and associated measurement RSs may be given in the Handover (HO) or LTM configuration.

[0187] In some embodiments, the CSI report is configured to be sent to the candidate cell after receiving the cell switch command indicating the candidate cell for cell switch.

[0188] In some embodiments, the first apparatus 110 may transmit, to the target cell, information about the reference slot, that is the most recently determined, for the CSI report.

[0189] In some embodiments, the information may be sent by a serving cell of the first apparatus to the candidate cell such that the candidate cell derives the reference slot.

[0190] For example, for a CSI report sent to a candidate / target cell, the information about the most recently determined slot (N) may be sent to the candidate / target cell (such that the candidate cell may also derive the slot (N) similar way as the first apparatus 110).

[0191] In one option, the information may indicate the most recently determined slot (N), e.g., offset between slot (N) and the UL slot containing the information

[0192] In one option, the information about the most recently determined slot (N) may be sent along with the report, e.g., it may be defined as a part of the report content.

[0193] In one option, the information about the most recently determined slot (N) may be sent by the serving cell (source cell) to the candidate cell such that the candidate cell may also derive the slot (N) in a similar way as the first apparatus 110.

[0194] Furthermore, in another aspect, a distinct method for defining a valid CSI reference resource and a valid reporting slot requirement, using the cell switch command as the reference and minimum latency requirements, will be further described as below.

[0195] In some example embodiments, for a CSI report for a (mobility) candidate cell, the first apparatus 110 may derive a timeline for a valid reporting (or a valid CSI report) and / or a CSI reference resource based on a reference point determined by the timing of the reception of the cell switch command. A valid reporting or a valid CSI report may refer to the scenario when the UE shall expect to send a CSI report; otherwise, the UE may (or allowed to) omit the report (if the reporting or CSI report is not valid).

[0196] The reference point mentioned here may be the downlink slot containing either the control channel (PDCCH) scheduling the data channel (PDSCH) or the data channel (PDSCH) carrying the information of cell switch command (CSC), or based on the uplink slot carrying the uplink information of acknowledgement for the reception of the cell switch command.

[0197] FIG. 6 illustrates an example diagram related to CSI reporting timeline for candidate cell CSI acquisition using the CSC as the reference in accordance with some example embodiments of the present disclosure.

[0198] As an option, the first apparatus 110 may provide a valid CSI report (or a CSI report) to the target cell if the first uplink symbol carrying the CSI report (including the effect of the timing advance) starts no earlier than a first time gap (e.g., the first time gap 610 in FIG. 6) and a second time gap (e.g., the second time gap 620 in FIG. 6).

[0199] For example, the first time gap may be after the last symbol of the reference point, where the first time gap may be defined based on the CSI computation or processing delay (e.g., a function ofZ) and some other physical layer constraints such as time requires for downlink to uplink switching and the second time gap after the first measurement RS transmission occasion following the last symbol of the reference point, where the second time gap may be defined based on the CSI computation or processing delay (e.g., a function of Z’).

[0200] The CSI reference resource may be defined as the slot carrying the first measurement RS transmission occasion following the last symbol of the reference point. This may be applied for the UEs not capable of making measurements before the reception of the cell switch command or for the UEs which start to make or continue to make or are configure to make measurements after the reception of the cell switch command. Therefore, this option for determining valid CSI report to the target cell may be used along with the option 3 for determining the first reference point and the reference (uplink) slot based on a reception of cell switch command. In some examples, this option for determining valid CSI report to the target cell may be used along with the option 3 for determining the first reference point and the reference (uplink) slot, and applying X as the first time gap, and nCSI ref (used to determine the CSI reference resource) as the second time gap.

[0201] FIG. 7 illustrates an example diagram related to CSI reporting timeline forcandidate cell CSI acquisition using the CSC as the reference in accordance with some example embodiments of the present disclosure

[0202] As another option, the first apparatus 110 may provide a valid CSI report to the target cell if the first uplink symbol carrying the CSI report (including the effect of the timing advance) starts no earlier than a first time gap and a second time gap (e.g., the second time gap 710 in FIG. 7).

[0203] For example, the first time gap may be after the last symbol of the reference point, where the first time gap may zero or defined based on the minimum physical layer constraints such as time requires for downlink to uplink switching and a second time gap may be after the last measurement RS transmission occasion before the last symbol of the reference point, where the second time gap may be defined based on the CSI computation or processing delay (e.g., a function of Z’).

[0204] In some embodiments, the CSI reference resource may be defined as the downlink slot containing either the control channel (PDCCH) scheduling the data channel (PDSCH) or the data channel (PDSCH) carrying the information of cell switch command (CSC). This may be applied for the UE capable of making measurements before the reception of the cell switch command. Therefore, this option for determining valid CSI report to the target cell may be used along with the options for determining the first reference point and the reference (uplink) slot based on the mobility configuration or control command. In some examples, this option for determining valid CSI report to the target cell may be used along options for determining the first reference point and the reference (uplink) slot based on the mobility configuration or control command occurring before the cell switch command, and applying X as the first time gap, and nCSI ref (used to determine the CSI reference resource) as the second time gap.

[0205] In this way, CSI reference resource for CSI reporting to the target cell can be defined for both scenarios: measurements performed before and after the reception of the cell switch command.

[0206] Also, valid measurement RS occasions and valid CSI reporting can be defined to support CSI acquisition for a candidate cell in both scenarios: measurements performed before and after the reception of the cell switch command.

[0207] FIG. 8 shows a flowchart of an example method 800 implemented at a firstapparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0208] At block 810, the first apparatus receives, from a second apparatus, a mobility configuration at least comprising a configuration of CSI-RSs for CSI acquisition of at least one candidate cell.

[0209] At block 820, the first apparatus determines a reference slot, to be used for CSI acquisition of the at least one candidate cell, based at least on a first reference point at least partially related to a reception of the mobility configuration or a control command.

[0210] At block 830, the first apparatus determines channel measurements for CSI acquisition of the at least one candidate cell based on one or more measurement occasions determined relative to the reference slot.

[0211] In some example embodiments, the one or more measurement occasions are no later than a CSI reference resource associated with the reference slot that is the most recently determined.

[0212] In some example embodiments, the reference slot, that is the most recently determined, is with respect to a slot, which is an uplink slot carrying a CSI report containing the information of CSI acquisition to a candidate cell after a reception of a cell switch command indicating a cell switch to the candidate cell.

[0213] In some example embodiments, the method 800 further comprises: determining the reference slot based on a first reference point and a time gap.

[0214] In some example embodiments, the reference slot starts after a time gap after the end of the first reference point.

[0215] In some example embodiments, the first reference point is defined based on a downlink slot containing either a control channel scheduling a data channel or a data channel carrying the information of the mobility configuration.

[0216] In some example embodiments, the first reference point is defined based on an uplink slot carrying uplink information of an acknowledgement for a reception of the mobility configuration.

[0217] In some example embodiments, the first reference point is defined based on adownlink slot where a control command containing information related to the at least one candidate cell is received.

[0218] In some example embodiments, the control command comprises at least one of the following: a control command for activating CSI measurements associated with the CSI acquisition for the at least one candidate cell, a control command for a candidate transmission configuration indicator, TCI, activation / deactivation command for activating / deactivating a TCI state associated with the at least one candidate cell or the CSI-RS to be measured for the CSI acquisition for the at least one candidate cell, a physical downlink control channel, PDCCH, order triggering a random access channel, RACH, transmission towards the at least one candidate cell, or a physical downlink control channel, PDCCH, order triggering a random access channel, RACH, transmission associated with the CSI-RS to be measured for the CSI acquisition for the at least one candidate cell.

[0219] In some example embodiments, the first reference point is defined based on an uplink slot carrying the uplink information of an acknowledgement for the reception of the control command.

[0220] In some example embodiments, at least one subsequent reference slot after the first reference slot is defined using the most recently determined reference slot as the first reference point or using the most recently determined CSI reference resource calculated based on the most recently determined reference slot as the first reference point.

[0221] In some example embodiments, the time gap is defined as the smallest value greater than or equal to a time period, such that a location, starting after a time gap after the end of the first reference point, corresponds to a valid uplink slot.

[0222] In some example embodiments, the time gap is specified based on a capability of the first apparatus, or is configured by the mobility configuration, a configuration of CSI-RSs for CSI acquisition of the at least one candidate cell, or a CSI report configuration.

[0223] In some example embodiments, the first reference point and the time gap are calculated using at least one configuration parameter based on a serving cell configuration, or a candidate cell configuration or both serving cell and candidate cell configurations, wherein the serving cell is a serving cell of the first apparatus, and the candidate cell is acandidate cell for which the CSI acquisition is being performed.

[0224] In some example embodiments, the at least one configuration parameter is at least one of: sub-carrier spacing configuration associated with a downlink slot or channel or signal; sub-carrier spacing configuration associated with an uplink slot or channel or signal; timing of a downlink slot; timing of an uplink slot; slot format; timing of a frame or frame timing.

[0225] In some example embodiments, the at least one configuration parameter is configured by the mobility configuration.

[0226] In some example embodiments, the method 800 further comprises: determining the CSI reference resource based on the determined reference slot and a time gap.

[0227] In some example embodiments, the time gap is defined based on a specific value or based on a CSI computation delay or based on a capability of the first apparatus.

[0228] In some example embodiments, the method 800 further comprises: receiving a cell switch command indicating a candidate cell as the target cell for a cell switch; transmitting, to the target cell, information about the reference slot, that is the most recently determined, for the CSI report.

[0229] In some example embodiments, the information is sent by a serving cell of the first apparatus to the candidate cell such that the candidate cell derives the reference slot.

[0230] In some example embodiments, the method 800 further comprises: receiving a cell switch command from the second apparatus indicating a candidate cell as the target cell for a cell switch; transmitting, to the target cell, the CSI report generated based on the measurements determined based on the reference slot that is the most recently determined, wherein the CSI report includes information of acquired CSI related to one or more measurement quantities for the target cell.

[0231] In some example embodiments, the measurement quantity comprises at least one of the following: a rank indication, RI, a precoding matrix indicator, PMI, a channel quality indicator, CQI, or a CSI-RS resource indicator, CRI, a layer indicator, LI, or a reference signal receiving power, RSRP.

[0232] In some example embodiments, the method 800 further comprises: performing measurements for the CSI acquisition for the at least one candidate cell before thereception of the cell switch command.

[0233] In some example embodiments, the method 800 further comprises: sending a capability information indicating a support to perform measurements for the CSI acquisition for the at least one candidate cell before the reception of the cell switch command.

[0234] In some example embodiments, the mobility configuration is a radio resource control signaling comprising Layerl / Layer2 triggered mobility, LTM, configuration or handover-related configuration

[0235] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network node.

[0236] FIG. 9 shows a flowchart of an example method 900 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0237] At block 910, the first apparatus receives, from a second apparatus, a mobility configuration at least comprising a configuration of CSI-RSs for CSI acquisition of at least one candidate cell.

[0238] At block 920, the first apparatus receiving, from a second apparatus, a cell switch command indicating the at least one candidate cell as a target cell for a cell switch.

[0239] At block 930, the first apparatus determines a reference slot, to be used for CSI acquisition for the target cell, based at least on a first reference point at least partially related to a reception of a cell switch command.

[0240] At block 940, determining channel measurements for CSI acquisition for the target cell based on the one or more measurement occasions determined relative to the reference slot.

[0241] In some example embodiments, the one or more measurement occasions are no later than a CSI reference resource associated with the reference slot that is the most recently determined.

[0242] In some example embodiments, the reference slot, that is the most recently determined, is with respect to a slot, which is an uplink slot carrying the CSI reportcontaining the information of CSI acquisition to the target cell.

[0243] In some example embodiments, the method 900 further comprises: determining the reference slot based on a first reference point and a time gap.

[0244] In some example embodiments, the reference slot starts after a time gap after the end of the first reference point.

[0245] In some example embodiments, the method 900 further comprises: performing measurements for the CSI acquisition for the target cell after the reception of the cell switch command.

[0246] In some example embodiments, the first reference point is defined based on a downlink slot containing either a control channel scheduling the data channel carrying information of the cell switch command or a data channel carrying information of the cell switch command.

[0247] In some example embodiments, the first reference point is defined based on an uplink slot carrying uplink information of an acknowledgement for a reception of the cell switch command.

[0248] In some example embodiments, at least one subsequent reference slot after the first reference slot is defined using the most recently determined reference slot as the first reference point or using the most recently determined CSI reference resource calculated based on the most recently determined reference slot as the first reference point.

[0249] In some example embodiments, the time gap is defined as the smallest value greater than or equal to a time period, such that a location, starting after a time gap after the end of the first reference point, corresponds to a valid uplink slot.

[0250] In some example embodiments, the time gap is specified based on a capability of the first apparatus, or is configured by the mobility configuration, a configuration of CSI-RSs for CSI acquisition of the target cell or a CSI report configuration.

[0251] In some example embodiments, the first reference point and the time gap are calculated using at least one configuration parameter based on a serving cell configuration of a serving cell of the first apparatus, or a candidate cell configuration or both serving cell and candidate cell configurations, wherein the serving cell is a serving of the first apparatus before the cell switch, and the candidate cell is the target cell indicated in thecell switch command for a cell switch.

[0252] In some example embodiments, the at least one configuration parameter is at least one of: sub-carrier spacing configuration associated with a downlink slot or channel or signal; sub-carrier spacing configuration associated with an uplink slot or channel or signal; timing of a downlink slot; timing of an uplink slot; slot format; timing of a frame or frame timing.

[0253] In some example embodiments, the at least one configuration parameter is configured by the mobility configuration.

[0254] In some example embodiments, the method 900 further comprises: determining the CSI reference resource based on the determined reference slot and a time gap.

[0255] In some example embodiments, the time gap is defined based on a specific value or based on a CSI computation delay or based on a capability of the first apparatus.

[0256] In some example embodiments, the method 900 further comprises: transmitting, to the target cell, information about the reference slot, that is the most recently determined, for the CSI report.

[0257] In some example embodiments, the information is sent by a serving cell of the first apparatus to the candidate cell such that the candidate cell derives the reference slot.

[0258] In some example embodiments, the method 900 further comprises: transmitting, to the target cell, the CSI report generated based on the measurements determined based on the reference slot that is the most recently determined, wherein the CSI report includes information of acquired CSI related to one or more measurement quantities for the target cell.

[0259] In some example embodiments, the measurement quantity comprises at least one of the following: a rank indication, RI, a precoding matrix indicator, PMI, a channel quality indicator, CQI, or a CSI-RS resource indicator, CRI, a layer indicator, LI, or a reference signal receiving power, RSRP.

[0260] In some example embodiments, the mobility configuration is a radio resource control signaling comprising Layerl / Layer2 triggered mobility, LTM configuration or handover-related configuration

[0261] In some example embodiments, the first apparatus comprises a terminal deviceand the second apparatus comprises a network node.

[0262] FIG. 10 shows a flowchart of an example method 1000 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1000 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0263] At block 1010, the first apparatus receives, from a second apparatus, a mobility configuration at least comprising a configuration of CSI-RSs for a CSI acquisition of at least one candidate cell.

[0264] At block 1020, the first apparatus receives a cell switch command indicating the at least one candidate cell as a target cell.

[0265] At block 1030, the first apparatus determines, based on at least a reference point determined by a timing of a reception of the cell switch command, a timeline for at least one of a CSI report carrying the information related to CSI acquisition to the target cell or a CSI reference resource.

[0266] In some example embodiments, the reference point is defined based on a downlink slot containing either a control channel scheduling the data channel carrying information of the cell switch command or a data channel carrying information of the cell switch command.

[0267] In some example embodiments, the reference point is defined based on an uplink slot carrying uplink information of an acknowledgement for a reception of the cell switch command.

[0268] In some example embodiments, the method 1000 further comprises: transmitting, to the target cell, the CSI report in accordance with a first uplink symbol carrying the CSI report starting no earlier than: a first time gap after the last symbol of the reference point, where the first time gap is defined based on the a CSI computation or processing delay or a time requirement for downlink to uplink switching, and a second time gap after the first measurement RS transmission occasion following the last symbol of the reference point, where the second time gap is defined based on a CSI computation or a processing delay.

[0269] In some example embodiments, the CSI reference resource is defined as a slot carrying the first measurement RS transmission occasion following the last symbol of thereference point.

[0270] In some example embodiments, the method 1000 further comprises: performing measurements for the CSI acquisition for the target cell after the reception of the cell switch command.

[0271] In some example embodiments, the method 1000 further comprises: transmitting, to the target cell, the CSI report in accordance with a first uplink symbol carrying the CSI report starting no earlier than: a first time gap after the last symbol of the reference point, where the first time gap is zero or defined based on a time requirement for downlink to uplink switching, and a second time gap after the last measurement RS transmission occasion before the first or last symbol of the reference point, where the second time gap is defined based on a CSI computation or a processing delay.

[0272] In some example embodiments, the CSI reference resource is defined based on a downlink slot containing either a control channel scheduling the data channel carrying information of the cell switch command or a data channel carrying information of the cell switch command.

[0273] In some example embodiments, the method 1000 further comprises: performing measurements for the CSI acquisition for at least one candidate cell before the reception of the cell switch command.

[0274] In some example embodiments, the method 1000 further comprises: sending a capability information indicating a support to perform measurements for the CSI acquisition for the at least one candidate cell before the reception of the cell switch command

[0275] In some example embodiments, the first time gap or the second time gap is calculated using at least one configuration parameter based on a serving cell configuration, or a candidate cell configuration or both serving cell and candidate cell configurations, wherein the serving cell is a serving of the first apparatus before the cell switch, and the candidate cell is the target cell indicated in the cell switch command for a cell switch.

[0276] In some example embodiments, the at least one configuration parameter is at least one of: sub-carrier spacing configuration associated with a downlink slot or channel or signal; sub-carrier spacing configuration associated with an uplink slot or channel or signal; timing of a downlink slot; timing of an uplink slot; slot format; timing of a frameor frame timing.

[0277] In some example embodiments, the at least one configuration parameter is configured by the mobility configuration.

[0278] In some example embodiments, the mobility configuration is a radio resource control signaling comprising Layerl / Layer2 triggered mobility, LTM configuration or handover-related configuration

[0279] In some example embodiments, the information related to CSI acquisition comprises at least one of the following: a rank indication, RI, a precoding matrix indicator, PMI, a channel quality indicator, CQI, or a CSI-RS resource indicator, CRI, a layer indicator, LI, or a reference signal receiving power, RSRP.

[0280] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network node.

[0281] In some example embodiments, a first apparatus capable of performing any of the method 800 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0282] In some example embodiments, the first apparatus comprises means for receiving, from a second apparatus, a mobility configuration at least comprising a configuration of CSI-RSs for CSI acquisition of at least one candidate cell; means for determining a reference slot, to be used for CSI acquisition of the at least one candidate cell, based at least on a first reference point at least partially related to a reception of the mobility configuration or a control command; and means for determining channel measurements for CSI acquisition of the at least one candidate cell based on one or more measurement occasions determined relative to the reference slot.

[0283] In some example embodiments, the one or more measurement occasions are no later than a CSI reference resource associated with the reference slot that is the most recently determined.

[0284] In some example embodiments, the reference slot, that is the most recentlydetermined, is with respect to a slot, which is an uplink slot carrying a CSI report containing the information of CSI acquisition to a candidate cell after a reception of a cell switch command indicating a cell switch to the candidate cell.

[0285] In some example embodiments, the first apparatus further comprises: means for determining the reference slot based on a first reference point and a time gap.

[0286] In some example embodiments, the reference slot starts after a time gap after the end of the first reference point.

[0287] In some example embodiments, the first reference point is defined based on a downlink slot containing either a control channel scheduling a data channel or a data channel carrying the information of the mobility configuration.

[0288] In some example embodiments, the first reference point is defined based on an uplink slot carrying uplink information of an acknowledgement for a reception of the mobility configuration.

[0289] In some example embodiments, the first reference point is defined based on a downlink slot where a control command containing information related to the at least one candidate cell is received.

[0290] In some example embodiments, the control command comprises at least one of the following: a control command for activating CSI measurements associated with the CSI acquisition for the at least one candidate cell, a control command for a candidate transmission configuration indicator, TCI, activation / deactivation command for activating / deactivating a TCI state associated with the at least one candidate cell or the CSI-RS to be measured for the CSI acquisition for the at least one candidate cell, a physical downlink control channel, PDCCH, order triggering a random access channel, RACH, transmission towards the at least one candidate cell, or a physical downlink control channel, PDCCH, order triggering a random access channel, RACH, transmission associated with the CSI-RS to be measured for the CSI acquisition for the at least one candidate cell.

[0291] In some example embodiments, the first reference point is defined based on an uplink slot carrying the uplink information of an acknowledgement for the reception of the control command.

[0292] In some example embodiments, at least one subsequent reference slot after the first reference slot is defined using the most recently determined reference slot as the first reference point or using the most recently determined CSI reference resource calculated based on the most recently determined reference slot as the first reference point.

[0293] In some example embodiments, the time gap is defined as the smallest value greater than or equal to a time period, such that a location, starting after a time gap after the end of the first reference point, corresponds to a valid uplink slot.

[0294] In some example embodiments, the time gap is specified based on a capability of the first apparatus, or is configured by the mobility configuration, a configuration of CSI-RSs for CSI acquisition of the at least one candidate cell, or a CSI report configuration.

[0295] In some example embodiments, the first reference point and the time gap are calculated using at least one configuration parameter based on a serving cell configuration, or a candidate cell configuration or both serving cell and candidate cell configurations, wherein the serving cell is a serving cell of the first apparatus, and the candidate cell is a candidate cell for which the CSI acquisition is being performed.

[0296] In some example embodiments, the at least one configuration parameter is at least one of sub-carrier spacing configuration associated with a downlink slot or channel or signal; sub-carrier spacing configuration associated with an uplink slot or channel or signal; timing of a downlink slot; timing of an uplink slot; slot format; timing of a frame or frame timing.

[0297] In some example embodiments, the at least one configuration parameter is configured by the mobility configuration.

[0298] In some example embodiments, the first apparatus further comprises: means for determining the CSI reference resource based on the determined reference slot and a time gap.

[0299] In some example embodiments, the time gap is defined based on a specific value or based on a CSI computation delay or based on a capability of the first apparatus.

[0300] In some example embodiments, the first apparatus further comprises: means for receiving a cell switch command indicating a candidate cell as the target cell for a cell switch; means for transmitting, to the target cell, information about the reference slot, thatis the most recently determined, for the CSI report.[030 l]In some example embodiments, the information is sent by a serving cell of the first apparatus to the candidate cell such that the candidate cell derives the reference slot.

[0302] In some example embodiments, the first apparatus further comprises: means for receiving a cell switch command from the second apparatus indicating a candidate cell as the target cell for a cell switch; means for transmitting, to the target cell, the CSI report generated based on the measurements determined based on the reference slot that is the most recently determined, wherein the CSI report includes information of acquired CSI related to one or more measurement quantities for the target cell.

[0303] In some example embodiments, the measurement quantity comprises at least one of the following: a rank indication, RI, a precoding matrix indicator, PMI, a channel quality indicator, CQI, or a CSI-RS resource indicator, CRI, a layer indicator, LI, or a reference signal receiving power, RSRP.

[0304] In some example embodiments, the first apparatus further comprises: means for performing measurements for the CSI acquisition for the at least one candidate cell before the reception of the cell switch command.

[0305] In some example embodiments, the first apparatus further comprises: means for sending a capability information indicating a support to perform measurements for the CSI acquisition for the at least one candidate cell before the reception of the cell switch command.

[0306] In some example embodiments, the mobility configuration is a radio resource control signaling comprising Layerl / Layer2 triggered mobility, LTM, configuration or handover-related configuration

[0307] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network node.

[0308] In some example embodiments, a first apparatus capable of performing any of the method 900 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the firstapparatus 110 in FIG. 1.

[0309] In some example embodiments, the first apparatus comprises means for receiving, from a second apparatus, a mobility configuration at least comprising a configuration of CSI-RSs for CSI acquisition of at least one candidate cell; means for receiving, from a second apparatus, a cell switch command indicating the at least one candidate cell as a target cell for a cell switch; means for determining a reference slot, to be used for CSI acquisition for the target cell, based at least on a first reference point at least partially related to a reception of a cell switch command; and means for determining channel measurements for CSI acquisition for the target cell based on the one or more measurement occasions determined relative to the reference slot.

[0310] In some example embodiments, the one or more measurement occasions are no later than a CSI reference resource associated with the reference slot that is the most recently determined.

[0311] In some example embodiments, the reference slot, that is the most recently determined, is with respect to a slot, which is an uplink slot carrying the CSI report containing the information of CSI acquisition to the target cell.

[0312] In some example embodiments, the first apparatus further comprises: means for determining the reference slot based on a first reference point and a time gap.

[0313] In some example embodiments, the reference slot starts after a time gap after the end of the first reference point.

[0314] In some example embodiments, the first apparatus further comprises: means for performing measurements for the CSI acquisition for the target cell after the reception of the cell switch command.

[0315] In some example embodiments, the first reference point is defined based on a downlink slot containing either a control channel scheduling the data channel carrying information of the cell switch command or a data channel carrying information of the cell switch command.

[0316] In some example embodiments, the first reference point is defined based on an uplink slot carrying uplink information of an acknowledgement for a reception of the cell switch command.

[0317] In some example embodiments, at least one subsequent reference slot after the first reference slot is defined using the most recently determined reference slot as the first reference point or using the most recently determined CSI reference resource calculated based on the most recently determined reference slot as the first reference point.

[0318] In some example embodiments, the time gap is defined as the smallest value greater than or equal to a time period, such that a location, starting after a time gap after the end of the first reference point, corresponds to a valid uplink slot.

[0319] In some example embodiments, the time gap is specified based on a capability of the first apparatus, or is configured by the mobility configuration, a configuration of CSI-RSs for CSI acquisition of the target cell or a CSI report configuration.

[0320] In some example embodiments, the first reference point and the time gap are calculated using at least one configuration parameter based on a serving cell configuration of a serving cell of the first apparatus, or a candidate cell configuration or both serving cell and candidate cell configurations, wherein the serving cell is a serving of the first apparatus before the cell switch, and the candidate cell is the target cell indicated in the cell switch command for a cell switch.[032 l]In some example embodiments, the at least one configuration parameter is at least one of sub-carrier spacing configuration associated with a downlink slot or channel or signal; sub-carrier spacing configuration associated with an uplink slot or channel or signal; timing of a downlink slot; timing of an uplink slot; slot format; timing of a frame or frame timing.

[0322] In some example embodiments, the at least one configuration parameter is configured by the mobility configuration.

[0323] In some example embodiments, the first apparatus further comprises: means for determining the CSI reference resource based on the determined reference slot and a time gap.

[0324] In some example embodiments, the time gap is defined based on a specific value or based on a CSI computation delay or based on a capability of the first apparatus.

[0325] In some example embodiments, the first apparatus further comprises: means for transmitting, to the target cell, information about the reference slot, that is the mostrecently determined, for the CSI report.

[0326] In some example embodiments, the information is sent by a serving cell of the first apparatus to the candidate cell such that the candidate cell derives the reference slot.

[0327] In some example embodiments, the first apparatus further comprises: means for transmitting, to the target cell, the CSI report generated based on the measurements determined based on the reference slot that is the most recently determined, wherein the CSI report includes information of acquired CSI related to one or more measurement quantities for the target cell.

[0328] In some example embodiments, the measurement quantity comprises at least one of the following: a rank indication, RI, a precoding matrix indicator, PMI, a channel quality indicator, CQI, or a CSI-RS resource indicator, CRI, a layer indicator, LI, or a reference signal receiving power, RSRP.

[0329] In some example embodiments, the mobility configuration is a radio resource control signaling comprising Layerl / Layer2 triggered mobility, LTM configuration or handover-related configuration

[0330] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network node.

[0331] In some example embodiments, a first apparatus capable of performing any of the method 1000 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 1000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0332] In some example embodiments, the first apparatus comprises means for receiving, from a second apparatus, a mobility configuration at least comprising a configuration of CSI-RSs for a CSI acquisition of at least one candidate cell; means for receiving a cell switch command indicating the at least one candidate cell as a target cell; and means for determining, based on at least a reference point determined by a timing of a reception of the cell switch command, a timeline for at least one of a CSI report carrying the information related to CSI acquisition to the target cell or a CSI reference resource.

[0333] In some example embodiments, the reference point is defined based on a downlink slot containing either a control channel scheduling the data channel carrying information of the cell switch command or a data channel carrying information of the cell switch command.

[0334] In some example embodiments, the reference point is defined based on an uplink slot carrying uplink information of an acknowledgement for a reception of the cell switch command.

[0335] In some example embodiments, the first apparatus further comprises: means for transmitting, to the target cell, the CSI report in accordance with a first uplink symbol carrying the CSI report starting no earlier than: means for a first time gap after the last symbol of the reference point, where the first time gap is defined based on the a CSI computation or processing delay or a time requirement for downlink to uplink switching, and means for a second time gap after the first measurement RS transmission occasion following the last symbol of the reference point, where the second time gap is defined based on a CSI computation or a processing delay.

[0336] In some example embodiments, the CSI reference resource is defined as a slot carrying the first measurement RS transmission occasion following the last symbol of the reference point.

[0337] In some example embodiments, the first apparatus further comprises: means for performing measurements for the CSI acquisition for the target cell after the reception of the cell switch command.

[0338] In some example embodiments, the first apparatus further comprises: means for transmitting, to the target cell, the CSI report in accordance with a first uplink symbol carrying the CSI report starting no earlier than: means for a first time gap after the last symbol of the reference point, where the first time gap is zero or defined based on a time requirement for downlink to uplink switching, and means for a second time gap after the last measurement RS transmission occasion before the first or last symbol of the reference point, where the second time gap is defined based on a CSI computation or a processing delay.

[0339] In some example embodiments, the CSI reference resource is defined based on a downlink slot containing either a control channel scheduling the data channel carryinginformation of the cell switch command or a data channel carrying information of the cell switch command.

[0340] In some example embodiments, the first apparatus further comprises: means for performing measurements for the CSI acquisition for at least one candidate cell before the reception of the cell switch command.

[0341] In some example embodiments, the first apparatus further comprises: means for sending a capability information indicating a support to perform measurements for the CSI acquisition for the at least one candidate cell before the reception of the cell switch command

[0342] In some example embodiments, the first time gap or the second time gap is calculated using at least one configuration parameter based on a serving cell configuration, or a candidate cell configuration or both serving cell and candidate cell configurations, wherein the serving cell is a serving of the first apparatus before the cell switch, and the candidate cell is the target cell indicated in the cell switch command for a cell switch.

[0343] In some example embodiments, the at least one configuration parameter is at least one of: sub-carrier spacing configuration associated with a downlink slot or channel or signal; sub-carrier spacing configuration associated with an uplink slot or channel or signal; timing of a downlink slot; timing of an uplink slot; slot format; timing of a frame or frame timing.

[0344] In some example embodiments, the at least one configuration parameter is configured by the mobility configuration.

[0345] In some example embodiments, the mobility configuration is a radio resource control signaling comprising Layerl / Layer2 triggered mobility, LTM configuration or handover-related configuration

[0346] In some example embodiments, the information related to CSI acquisition comprises at least one of the following: a rank indication, RI, a precoding matrix indicator, PMI, a channel quality indicator, CQI, or a CSI-RS resource indicator, CRI, a layer indicator, LI, or a reference signal receiving power, RSRP.

[0347] In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network node.

[0348] FIG. 11 is a simplified block diagram of a device 1100 that is suitable for implementing example embodiments of the present disclosure. The device 1100 may be provided to implement a communication device, for example, the terminal device 110 or the network device 120 as shown in FIG. 1. As shown, the device 1100 includes one or more processors 1110, one or more memories 1120 coupled to the processor 1110, and one or more communication modules 1140 coupled to the processor 1110.

[0349] The communication module 1140 is for bidirectional communications. The communication module 1140 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 1140 may include at least one antenna.

[0350] The processor 1110 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1100 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0351] The memory 1120 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1124, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random-access memory (RAM) 1122 and other volatile memories that will not last in the power-down duration.

[0352] A computer program 1130 includes computer executable instructions that are executed by the associated processor 1110. The instructions of the program 1130 may include instructions for performing operations / acts of some example embodiments of the present disclosure. The program 1130 may be stored in the memory, e.g., the ROM 1124. The processor 1110 may perform any suitable actions and processing by loading the program 1130 into the RAM 1122.

[0353] The example embodiments of the present disclosure may be implemented by means of the program 1130 so that the device 1100 may perform any process of the disclosure as discussed with reference to FIG. 2 to FIG. 10. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0354] In some example embodiments, the program 1130 may be tangibly contained in a computer readable medium which may be included in the device 1100 (such as in the memory 1120) or other storage devices that are accessible by the device 1100. The device 1100 may load the program 1130 from the computer readable medium to the RAM 1122 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. 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).

[0355] FIG. 12 shows an example of the computer readable medium 1200 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 1200 has the program 1130 stored thereon.

[0356] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. Although various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0357] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non-transitory computer readable medium. The computer program product includes computerexecutable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods asdescribed above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0358] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0359] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0360] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0361] Further, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of a single embodiment may also be implemented in a plurality of embodiments separately or in any suitable sub-combination.

[0362] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:

1. A first apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to:receive, from a second apparatus, a mobility configuration at least comprising a configuration of channel state information reference signals, CSI-RSs, for a CSI acquisition of at least one candidate cell;receive a cell switch command indicating the at least one candidate cell as a target cell; anddetermine, based on at least a reference point determined by a timing of a reception of the cell switch command, a timeline for at least one of a CSI report carrying the information related to CSI acquisition to the target cell or a CSI reference resource.

2. The first apparatus of claim 1, wherein the reference point is defined based on a downlink slot containing either a control channel scheduling the data channel carrying information of the cell switch command or a data channel carrying information of the cell switch command.

3. The first apparatus of claim 1, wherein the reference point is defined based on an uplink slot carrying uplink information of an acknowledgement for a reception of the cell switch command.

4. The first apparatus of claim 2 or 3, wherein the first apparatus is caused to: transmit, to the target cell, the CSI report in accordance with a first uplink symbol carrying the CSI report starting no earlier than:a first time gap after the last symbol of the reference point, where the first time gap is defined based on the a CSI computation or processing delay or a time requirement for downlink to uplink switching, anda second time gap after the first measurement RS transmission occasion following the last symbol of the reference point, where the second time gap is defined based on a CSI computation or a processing delay.

5. The first apparatus of claim 4, wherein the CSI reference resource is defined as a slot carrying the first measurement RS transmission occasion following the last symbol of the reference point.

6. The first apparatus of claim 4 or 5, wherein the first apparatus is caused to: perform measurements for the CSI acquisition for the target cell after the reception of the cell switch command.

7. The first apparatus of claim 2 or 3, wherein the first apparatus is caused to: transmit, to the target cell, the CSI report in accordance with a first uplink symbol carrying the CSI report starting no earlier than:a first time gap after the last symbol of the reference point, where the first time gap is zero or defined based on a time requirement for downlink to uplink switching, and a second time gap after the last measurement RS transmission occasion before the first or last symbol of the reference point, where the second time gap is defined based on a CSI computation or a processing delay.

8. The first apparatus of claim 7, wherein the CSI reference resource is defined based on a downlink slot containing either a control channel scheduling the data channel carrying information of the cell switch command or a data channel carrying information of the cell switch command.

9. The first apparatus of claim 7 or 8, wherein the first apparatus is caused to: perform measurements for the CSI acquisition for at least one candidate cell before the reception of the cell switch command.

10. The first apparatus of claim 9, wherein the first apparatus is caused to: send a capability information indicating a support to perform measurements for the CSI acquisition for the at least one candidate cell before the reception of the cell switch command11. The first apparatus of any of claim 4 or claim 7, wherein the first time gap or the second time gap is calculated using at least one configuration parameter based on aserving cell configuration, or a candidate cell configuration or both serving cell and candidate cell configurations, wherein the serving cell is a serving of the first apparatus before the cell switch, and the candidate cell is the target cell indicated in the cell switch command for a cell switch.

12. The first apparatus of claim 11, wherein the at least one configuration parameter is at least one ofsub-carrier spacing configuration associated with a downlink slot or channel or signal;sub-carrier spacing configuration associated with an uplink slot or channel or signal; timing of a downlink slot;timing of an uplink slot;slot format;timing of a frame or frame timing.

13. The first apparatus of claim 11 or 12, wherein the at least one configuration parameter is configured by the mobility configuration.

14. The first apparatus of any of claims 1-13, wherein the mobility configuration is a radio resource control signaling comprising Layerl / Layer2 triggered mobility, LTM configuration or handover-related configuration15. The first apparatus of claim 1, wherein the information related to CSI acquisition comprises at least one of the following: a rank indication, RI, a precoding matrix indicator, PMI, a channel quality indicator, CQI, or a CSI-RS resource indicator, CRI, a layer indicator, LI, or a reference signal receiving power, RSRP.

16. The first apparatus of any of claims 1-15, wherein the first apparatus comprises a terminal device and the second apparatus comprises a network node.

17. A method comprising:receiving, at a first apparatus from a second apparatus, a mobility configuration at least comprising a configuration of channel state information reference signals, CSLRSs, for a CSI acquisition of at least one candidate cell;receiving a cell switch command indicating the at least one candidate cell as a target cell; anddetermining, based on at least a reference point determined by a timing of a reception of the cell switch command, a timeline for at least one of a C SI report carrying the information related to CSI acquisition to the target cell or a CSI reference resource.

18. A first apparatus comprising:means for receiving, from a second apparatus, a mobility configuration at least comprising a configuration of channel state information reference signals, CSI-RSs, for a CSI acquisition of at least one candidate cell;means for receiving a cell switch command indicating the at least one candidate cell as a target cell; andmeans for determining, based on at least a reference point determined by a timing of a reception of the cell switch command, a timeline for at least one of a CSI report carrying the information related to CSI acquisition to the target cell or a CSI reference resource.

19. A computer readable medium comprising instructions stored thereon for causing an apparatus at least to perform the method of claim 4 or the method of claim 5 or the method of claim 17.

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