Candidate cell channel state information-reference signal configuration for cell switch

Abstract

A method, apparatus and computer program product are provided for provisioning channel state information reference signal (CSI-RS) configurations to a user equipment (UE) for layer-one (L1) measurement and cell configuration. In the context of a method, the method includes receiving at least CSI-RS configuration for a candidate cell from a network node, the at least one CSI-RS configuration comprising: a first set of CSI-RS configurations for L1 measurement; and a second set of CSI-RS configurations for candidate cell configuration; executing a cell switch to the candidate cell in response to a control message from the network node; and determining a subset of CSI-RSs of the candidate cell for at least one of beam management or CSI reporting based on the first set of CSI-RS configurations and the second set of CSI-RS configurations.

Description

CANDIDATE CELL CHANNEL STATE INFORMATION-REFERENCE SIGNALCONFIGURATION FOR CELL SWITCH TECHNICAL FIELD

[0001] An example embodiment relates generally to signaling techniques for provisioning aconfiguration of channel state information reference signal (CSI-RS) resources for a candidate cellto perform layer-one (L1) measurements for cell switch decisions and L1 measurements for candidate cell configuration, including beam management, CSI reporting, and / or the like. BACKGROUND

[0002] Common approaches to lower layer mobility also known as layer 1 / layer 2-triggered mobility (LTM) utilize synchronization signal block (SSB)-based L1 measurements to evaluate the quality of candidate cells for switch decisions. Such approaches typically generate SSBmeasurements over a narrow bandwidth with long periodicity and wider beams. As a result, SSB-based LTM switching may demonstrate poor time and frequency synchronization with the targetcell. Alternative measurements with narrower beam and links may be utilized to improve time andfrequency synchronization with the target cell; however, the triggering and reporting of alternativemeasurements may require alternative signaling approaches. For example, CSI-RS measurementsmay supplement SSB measurements; however, existing telecommunications approaches lack signaling procedures for configuring CSI-RS resources for a candidate cell to enable a userequipment (UE) to perform appropriate LTM L1 measurements and BM and / or CSI reporting L1measurements. BRIEF SUMMARY

[0003] A method, apparatus and computer program product are provided in accordance with an example embodiment in order to provision to a UE one or more CSI-RS configurations for a candidate cell. In various embodiments, the present method, apparatus, and computer program product provide improved solutions for indicating to a UE where CSI-RSs and / or configurationsfor pre-cell switch L1 measurement may be applied to BM and / or CSI L1 measurement post-cellswitch. In doing so, the method, apparatus, and computer program product may minimize the overall overhead of providing configurations of CSI-RSs to the UE.

[0004] In some embodiments, the method apparatus, and computer program product divide the CSI-RS configuration for a candidate cell into a first portion for L1 measurement of a candidatecell (e.g., for cell switch decision making purpose, handover measurements, and / or the like) and asecond portion for supporting configuration of the candidate cell (e.g., beam management (BM),CSI acquisition, and / or the like), where one or more subsets of the second portion may refer to orinclude one or more subsets of the first portion. In some embodiments, the method, apparatus, andcomputer program product provision, to the UE, configuration information of one or more CSI- RS resources, CSI-RS resource sets, CSI-RS resource configurations, and / or the like for LTMmeasurements. In some embodiments, the UE is configured to expect that measurement RSs for aLTM CSI reporting refer to CSI-RSs provided for LTM measurements. Additionally, the methodapparatus, and computer program product provide, to the UE, respective configurations of one ormore CSI-RSs for the candidate cell under the candidate configuration of the candidate cell. Invarious embodiments, the candidate configuration or candidate cell configuration of the candidatecell refers to RRCReconfiguration message, provided by ltm-CandidateConfig, which may containServingCellConfig or CellGroupConfig of the candidate cell, which is / are used by the UE aftercell switch to the candidate cell. The candidate configuration of the candidate cell may be referredto as candidate cell configuration herein.

[0005] In a first approach, the method, apparatus, and computer program product configure theUE to expect that measurement RSs for a CSI reporting for serving cell procedure (e.g., intra / inter-cell beam management, CSI acquisition, etc.) within the candidate cell may point to either CSI-RSs provided for LTM measurements or CSI-RSs provided under candidate cell configuration. Indoing so, the UE can refer to the first portion of the CSI-RSs (e.g., CSI-RS resources outside the candidate cell configuration) or the second portion (e.g., CSI-RS resources within the candidate cell configuration), thereby minimizing overhead.

[0006] In a second approach, in association with the cell switch to the candidate cell, the method,apparatus, and computer program product configure the UE to merge or combine the set of CSI-RSs given for LTM measurements for the candidate cell and the set of CSI-RSs under the candidatecell configuration of the candidate cell. Further, the UE may be configured to expect thatmeasurement RSs for a CSI reporting for serving cell procedure (e.g., intra / inter-cell beammanagement, CSI acquisition, etc.) within the candidate cell may point to CSI-RSs from thecombined set of CSI-RSs. After the UE is switched (or switches itself) to the target candidate cell,the UE may combine the first and second portions to determine and apply CSI-RSs and configurations thereof for the candidate cell (e.g., for BM, CSI acquisition, and / or the like). By causing the UE to generate and use a merged or combined list of configuration CSI-RSs, the method, apparatus, and computer program product may minimize overhead associated with providing the configuration of CSI-RS resources to the UE.

[0007] In at least one embodiment, a first method is provided that includes receiving, from a network node, at least one CSI-RS configuration for a candidate cell, the at least one CSI-RSconfiguration comprising: a first set of CSI-RS configurations for L! measurement on the candidatecell; and a second set of CSI-RS configurations for candidate cell configuration in association witha cell switch to the candidate cell; executing the cell switch to the candidate cell in response to a control message from the network node, wherein: the control message is based at least in part ona report comprising at least one L1 measurement for at least one CSI-RS of the candidate cell; andthe at least one L1 measurement is generated based at least in part on the first set of CSI-RS configurations; and determining a subset of CSI-RSs of the candidate cell for at least one of BMor CSI reporting based at least in part on the first set of CSI-RS configurations and the second setof CSI-RS configurations.

[0008] In some embodiments, the method further includes generating the at least one L1measurement for the at least one CSI-RS of the candidate cell based at least in part on the first setof CSI-RS configurations; and provisioning to the network node the report comprising the at leastone L1 measurement. In some embodiments, in association with the cell switch, the candidate cellembodies a serving cell; and the method further comprises: generating at least one of at least oneBM measurement or at least one CSI L1 measurement on the determined subset of CSI-RSs of thecandidate cell; and provisioning to the candidate cell a report comprising at least one of the at leastone BM measurement or the at least one CSI L1 measurement to cause the candidate cell to perform at least one of BM or CSI adaptation based at least in part on the report.

[0009] In some embodiments, the method further includes decoding the second set of CSI-RS configurations in response to the executing of the cell switch to the candidate cell. In some embodiments, a respective set of CSI-RS configurations comprises at least one CSI-RS resourceconfiguration for a respective CSI-RS of the candidate cell. In some embodiments, the at least oneCSI-RS resource configuration indicates at least one non-zero power (NZP) CSI-RS resource set for a respective CSI-RS of the candidate cell. In some embodiments, the candidate cell embodies an LTM candidate cell. In some embodiments, the network node embodies a gNodeB.

[0010] As further described below, in some embodiments, one or more operations of the above-described methods are performed by an apparatus including at least one processor and at least onememory storing instructions that, when executed by the at least one processor, cause the apparatusto perform the one or more operations. For example, an apparatus may include at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to i) receive, from a network node, at least one CSI-RSconfiguration for a candidate cell, the at least one CSI-RS configuration comprising: a first set ofCSI-RS configurations for L1 measurement on the candidate cell; and a second set of CSI-RS configurations for candidate cell configuration in association with a cell switch to the candidate cell; ii) execute the cell switch to the candidate cell in response to a control message from thenetwork node, wherein: the control message is based at least in part on a report comprising at leastone L1 measurement for at least one CSI-RS of the candidate cell; and the at least one L1 measurement is generated based at least in part on the first set of CSI-RS configurations; and iii)determine a subset of CSI-RSs of the candidate cell for at least one of BM or CSI reporting basedat least in part on the first set of CSI-RS configurations and the second set of CSI-RS configurations. In the same example, the apparatus may also perform other operations and / or embody additional aspects of the above-described methods.

[0011] In various embodiments, as further described below, provided herein is a computer program product including at least one non-transitory computer-readable storage medium having computer- executable program code instructions stored therein, the computer-executable program code instructions including program code instructions configured for performing one or more operations and / or embody additional aspects of the above-described methods. For example, a computer program product may include at least one non-transitory computer-readable storage mediumhaving computer-executable program code instructions stored therein, the computer- executableprogram code instructions including program code instructions configured to i) receive, from anetwork node, at least one CSI-RS configuration for a candidate cell, the at least one CSI- RSconfiguration comprising: a first set of CSI-RS configurations for L1 measurement on thecandidate cell; and a second set of CSI-RS configurations for candidate cell configuration inassociation with a cell switch to the candidate cell; ii) execute the cell switch to the candidate cellin response to a control message from the network node, wherein: the control message is based atleast in part on a report comprising at least one L1 measurement for at least one CSI-RS of the candidate cell; and the at least one L1 measurement is generated based at least in part on the firstset of CSI-RS configurations; and iii) determine a subset of CSI-RSs of the candidate cell for atleast one of BM or CSI reporting based at least in part on the first set of CSI-RS configurationsand the second set of CSI-RS configurations. In the same example, the program code instructionsmay also be configured to perform additional operations and / or embody additional aspects of theabove-described methods.

[0012] In various embodiments, as further described below, one or more operations of the above-described methods are performed by an apparatus having means for performing the one or more operations. For example, an apparatus may include i) means for receiving, from a network node, at least one CSI-RS configuration for a candidate cell, the at least one CSI-RS configuration comprising: a first set of CSI-RS configurations for L1 measurement on the candidate cell; and a second set of CSI-RS configurations for candidate cell configuration in association with a cellswitch to the candidate cell; ii) means for executing the cell switch to the candidate cell in responseto a control message from the network node, wherein: the control message is based at least in parton a report comprising at least one L1 measurement for at least one CSI-RS of the candidate cell;and the at least one L1 measurement is generated based at least in part on the first set of CSI-RSconfigurations; and iii) means for determining a subset of CSI-RSs of the candidate cell for at leastone of BM or CSI reporting based at least in part on the first set of CSI-RS configurations and thesecond set of CSI-RS configurations. In the same example, the apparatus may embody additionalaspects and / or include additional means for performing additional operations of the above- described methods.

[0013] In at least one embodiment, in accordance with the above-described first approach, a second method is provided that includes receiving, from a network node, at least one CSI-RS configuration for a candidate cell, the at least one CSI-RS configuration comprising: at least oneCSI-RS identifier for a respective RS of the candidate cell; and a respective CSI-RS configurationfor L1 measurement of the respective RS of the candidate cell; and executing the cell switch to thecandidate cell in response to a control message from the network node, wherein: the controlmessage is based at least in part on a report comprising at least one L1 measurement for at leastone CSI-RS of the candidate cell; and the at least one L1 measurement is generated based at leastin part on the at least one CSI-RS configuration; and determining a subset of CSI-RSs of thecandidate cell for at least one of BM or CSI reporting based at least in part on the at least one CSI-RS identifier and the respective CSI-RS configuration for L1 measurement of the respective RS ofthe candidate cell.

[0014] In some embodiments, the method further comprises generating the at least one L1measurement for the at least one CSI-RS of the candidate cell based at least in part on the at leastone CSI-RS configuration; and provisioning to the network node the report comprising the at leastone L1 measurement. In some embodiments, the method further comprises, in association with thecell switch to the candidate cell, determining a set of indices of CSI-RSs of the candidate cell basedat least in part on the at least one CSI-RS configuration, wherein the set of indices comprises anindex for the respective CSI-RS of the respective RS of the candidate cell; generating at least oneBM or CSI L1 measurement on a subset of CSI-RSs of the candidate cell based at least in part onthe set of indices of CSI-RSs of the candidate cell; and provisioning to the candidate cell a reportcomprising the at least one BM or CSI L1 measurement to cause the cell to perform BM or CSI adaptation based at least in part on the at least one BM or CSI L1 measurement.

[0015] In some embodiments, the method further comprises receiving, from the network node, atleast one of a report configuration message or a resource configuration message, wherein the reportconfiguration message or the resource configuration message comprises an indication to refer tothe at least one CSI-RS configuration for L1 measurement to determine the set of indices of CSI-RSs of the candidate cell for at least one of BM or CSI reporting for the candidate cell. In someembodiments, the at least one CSI-RS configuration comprises a first set of identifiers for at leastone CSI-RS, CSI resource set, or CSI resource configuration set associated with L1 measurementand a second set of CSI-RS identifiers for at least one CSI-RS, CSI resource set, or resourceconfiguration set associated with configuration of the candidate cell for at least one of BM or CSIreporting in association with the cell switch. In some embodiments, a respective CSI-RS identifierof the second set matches a respective CSI-RS of the first set; the second set comprises aconfiguration resource set for the respective CSI-RS identifier, the CSI configuration resource setbeing associated with configuration of the candidate cell and the cell switch; and the method further comprises: applying the configuration resource set of the second set to the generating of the at least one L1 measurement for the respective CSI-RS of the candidate cell.

[0016] In some embodiments, a respective CSI-RS identifier of the second set matches a respective CSI-RS of the first set; the first set comprises a configuration resource set for the respective CSI- RS identifier, the CSI configuration resource set being associated with L1 measurement of the respective RS of the candidate cell; and the method further comprises: applying the configuration resource set of the first set to the generating of the at least one L1 measurement for the respective CSI-RS of the candidate cell. In some embodiments, the at least one CSI-RS configuration comprises an indication of whether to apply a CSI configuration resource set of the first set or aCSI configuration resource set of the second set to the generating of the at least one L1measurement for the respective CSI-RS of the candidate cell.

[0017] In some embodiments, the method further includes provisioning, to the network node, amessage indicative of capability to support multi-part CSI-RS configuration for at least one of BMor CSI reporting for a candidate cell. In some embodiments, the message comprises a quantity ofsupportable candidate cells for LTM. In some embodiments, the provisioning of the message to the network node causes the network node to provision the message to at least one candidate cell to cause the at least one candidate cell to generate at least one CSI-RS report configuration and a respective association between the at least one CSI-RS report configuration and at least one CSI- RS resource configuration based at least in part on the message.

[0018] In some embodiments, the method further includes receiving from the network node an instruction to apply the at least one CSI-RS configuration for L1 measurement of the respectiveRS of the candidate cell to generate of at least one of at least one BM measurement or at least oneCSI L1 measurement of the candidate cell in association with the cell switch. In some embodiments, the candidate cell embodies an LTM candidate cell. In some embodiments, the network node embodies a gNodeB.

[0019] Alternatively, or additionally, in some embodiments, the second method includes receivingfrom a network node at least one configuration comprising: a set of L1 measurementconfigurations for a first set of NZP-CSI-RSs of a candidate cell; and a candidate cell configurationwith a second set of NZP-CSI-RSs of the candidate cell; generating a set of L1 measurements of the first set of NZP-CSI-RSs based at based at least in part on the set of L1 measurementconfigurations; provisioning to the network node a report comprising the set of L1 measurements;executing a cell switch to the candidate cell in response to a control message form the networknode, wherein the control message is based at least in part on the report comprising the set of L1measurements; generating a set of BM or CSI L1 measurements of the second set of NZP-CSI-RSs and the first set of NZP-CSI-RSs based at least in part on the set of candidate cell configurationand the set of L1 measurement configurations; and provisioning to the candidate cell the set of BMor CSI L1 measurements to cause the candidate cell to perform BM or CSI adaptation based at least in part on the set of BM or CSI L1 measurements

[0020] As further described below, in some embodiments, one or more operations of the above-described methods are performed by an apparatus including at least one processor and at least onememory storing instructions that, when executed by the at least one processor, cause the apparatusto perform the one or more operations. For example, an apparatus may include at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to i) receive, from a network node, at least one CSI-RS configuration for a candidate cell, the at least one CSI-RS configuration comprising: at least oneCSI-RS identifier for a respective RS of the candidate cell; and a respective CSI-RS configurationfor L1 measurement of the respective RS of the candidate cell; and ii) execute the cell switch to the candidate cell in response to a control message from the network node, wherein: the control message is based at least in part on a report comprising at least one L1 measurement for at leastone CSI-RS of the candidate cell; and the at least one L1 measurement is generated based at leastin part on the at least one CSI-RS configuration; and iii) determine a subset of CSI-RSs of thecandidate cell for at least one of BM or CSI reporting based at least in part on the at least one CSI-RS identifier and the respective CSI-RS configuration for L1 measurement of the respective RS ofthe candidate cell. In the same example, the apparatus may also perform other operations and / or embody additional aspects of the above-described methods.

[0021] In various embodiments, as further described below, provided herein is a computer program product including at least one non-transitory computer-readable storage medium having computer- executable program code instructions stored therein, the computer-executable program code instructions including program code instructions configured for performing one or more operations and / or embody additional aspects of the above-described methods. For example, a computer program product may include at least one non-transitory computer-readable storage mediumhaving computer-executable program code instructions stored therein, the computer- executableprogram code instructions including program code instructions configured to i) receive, from anetwork node, at least one channel state information reference signal (CSI-RS)configuration for a candidate cell, the at least one CSI-RS configuration comprising: at least oneCSI-RS identifier for a respective RS of the candidate cell; and a respective CSI-RS configurationfor L1 measurement of the respective RS of the candidate cell; and ii) execute the cell switch to the candidate cell in response to a control message from the network node, wherein: the control message is based at least in part on a report comprising at least one L1 measurement for at leastone CSI-RS of the candidate cell; and the at least one L1 measurement is generated based at leastin part on the at least one CSI-RS configuration; and iii) determine a subset of CSI-RSs of thecandidate cell for at least one of BM or CSI reporting based at least in part on the at least one CSI-RS identifier and the respective CSI-RS configuration for L1 measurement of the respective RS ofthe candidate cell. In the same example, the program code instructions may also be configured toperform additional operations and / or embody additional aspects of the above-described methods.

[0022] In various embodiments, as further described below, one or more operations of the above-described methods are performed by an apparatus having means for performing the one or more operations. For example, an apparatus may include i) means for receiving, from a network node,at least one CSI-RS configuration for a candidate cell, the at least one CSI-RS configurationcomprising: at least one CSI-RS identifier for a respective RS of the candidate cell; and a respectiveCSI-RS configuration for L1 measurement of the respective RS of the candidate cell; and ii) meansfor executing the cell switch to the candidate cell in response to a control message from the networknode, wherein: the control message is based at least in part on a report comprising at least one L1measurement for at least one CSI-RS of the candidate cell; and the at least one L1 measurement isgenerated based at least in part on the at least one CSI-RS configuration; and iii) means fordetermining a subset of CSI-RSs of the candidate cell for at least one of BM or CSI reporting basedat least in part on the at least one CSI-RS identifier and the respective CSI-RS configuration for L1 measurement of the respective RS of the candidate cell. In the same example, the apparatus may embody additional aspects and / or include additional means for performing additional operations of the above-described methods.

[0023] In at least one embodiment, in accordance with the above-described second approach, a third method is provided that includes receiving, from a network node, at least one CSI-RSconfiguration for a candidate cell, the at least one CSI-RS configuration comprising: a first portioncomprising: at least one CSI-RS identifier for a respective RS of the candidate cell; and at leastone CSI-RS configuration for L1 measurement of the respective RS of the candidate cell; and asecond portion comprising: at least one CSI-RS identifier for a second respective RS of the candidate cell; and a respective CSI-RS configuration of at least one RS of the candidate cell forat least one of BM or CSI reporting; executing the cell switch to the candidate cell in response toa control message from the network node, wherein: the control message is based at least in part ona report comprising at least one L1 measurement for the respective CSI-RS of the candidate cell; and the at least one L1 measurement for the respective CSI-RS of the candidate cell is generatedbased at least in part on the at least one CSI-RS configuration for L1 measurement of the respectiveRS of the first portion; generating a combined set of configuration CSI-RSs based at least in part on the at least one CSI-RS identifier of the first portion and the at least one CSI-RS identifier of the second portion; and determining a subset of CSI-RSs of the candidate cell for at least one of BM or CSI reporting based at least in part on: the combined set of CSI-RSs; and the respective CSI-RS configuration for at least one of BM or CSI reporting.

[0024] In some embodiments, the method further includes generating the at least one L1 measurement for the respective CSI-RS of the candidate cell based at least in part on the at leastone CSI-RS configuration for L1 measurement of the respective RS of the first portion; andprovisioning to the network node the report comprising the at least one L1 measurement. In someembodiments, a respective CSI-RS identifier of the at least one CSI-RS identifier of the firstportion matches a respective CSI-RS identifier of the at least one CSI-RS identifier of the secondportion; and the method further comprises: prioritizing the respective CSI-RS configuration fromthe second portion over the at least one CSI-RS configuration from the first portion in determiningthe subset of CSI-RSs of the candidate cell for at least one of BM or CSI reporting.

[0025] In some embodiments, a respective CSI-RS identifier of the at least one CSI-RS identifierof the first portion matches a respective CSI-RS identifier of the at least one CSI-RS identifier of the second portion; and the method further comprises: prioritizing the at least one CSI-RS configuration from the first portion in place of the respective CSI-RS configuration from the second portion in determining the subset of CSI-RSs of the candidate cell for at least one of BMor CSI reporting. In some embodiments, a respective CSI-RS identifier of the at least one CSI-RSidentifier of the first portion matches a respective CSI-RS identifier of the at least one CSI-RS identifier of the second portion; and the method further comprises: receiving an instruction fromthe network node; and based at least in part on the instruction determining whether to prioritize i)the at least one CSI-RS configuration from the first portion, or ii) the respective CSI-RSconfiguration from the second portion in determining the subset of CSI-RSs of the candidate cell for at least one of BM or CSI reporting.

[0026] In some embodiments, a respective CSI-RS identifier of the at least one CSI-RS identifierof the second portion embodies a reference to a respective CSI-RS identifier of the at least one CSI-RS identifier of the first portion; and the method further comprises: based at least in part on the reference embodied by the respective CSI-RS identifier, determining from the first portion a respective CSI-RS configuration of the at least one CSI-RS configuration for L1 measurement toenable use of the respective CSI-RS configuration for at least one of BM or CSI reporting. In someembodiments, the method further comprises receiving a configuration indication comprising a bitfield associated with at least one CSI-RS of the candidate cell, wherein: the bit field is configurablebetween a first value and a second value; and in the second value, the bit field indicates that arespective CSI-RS configuration for L1 measurement of the at least one CSI-RS configuration forL1 measurement applies to at least one of BM or CSI reporting on the candidate cell; and determining the subset of CSI-RSs of the candidate cell for at least one of BM or CSI reporting based at least in part on the respective CSI-RS configuration for L1 measurement.

[0027] In some embodiments, the configuration indication is received from the candidate cell. Insome embodiments, the method further comprises provisioning to the network node aconfiguration message indicative of capability to generate the combined set of configuration CSI-RSs based at least in part on: a respective one of the at least one CSI-RS identifier for a respectiveRS of the candidate cell; and a respective one of the at least one CSI-RS configuration for L1measurement of the respective RS of the candidate cell. In some embodiments, the method furthercomprises provisioning to the candidate cell a configuration message indicative of capability to generate the combined set of configuration CSI-RSs based at least in part on: a respective one ofthe at least one CSI-RS identifier for a respective RS of the candidate cell; and a respective one ofthe at least one CSI-RS configuration for L1 measurement of the respective RS of the candidatecell. In some embodiments, the configuration message comprises a quantity of supportablecandidate cells for which a respective combined set of configuration CSI-RSs may be generated.

[0028] In some embodiments, the method further comprises receiving a configuration message comprising an instruction to, in association with the executing of the cell switch, i) generate thecombined set of configuration CSI-RSs based at least in part on the at least one CSI-RS identifierof the first portion and the at least one CSI-RS identifier of the second portion, and ii) use thecombined set of configuration CSI-RSs in L1 measurement and at least one of BM or CSI reportingfor the candidate cell. In some embodiments, the configuration message is received from the network node. In some embodiments, the configuration message is received from the candidate cell. In some embodiments, the candidate cell embodies an LTM candidate cell. In some embodiments, the network node embodies a gNodeB.

[0029] As further described below, in some embodiments, one or more operations of the above-described methods are performed by an apparatus including at least one processor and at least onememory storing instructions that, when executed by the at least one processor, cause the apparatusto perform the one or more operations. For example, an apparatus may include at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to i) receive, from a network node, at least one CSI-RSconfiguration for a candidate cell, the at least one CSI-RS configuration comprising: a first portioncomprising: at least one CSI-RS identifier for a respective RS of the candidate cell; and at least one CSI-RS configuration for L1 measurement of the respective RS of the candidate cell; and a second portion comprising: at least one CSI-RS identifier for a second respective RS of the candidate cell; and a respective CSI-RS configuration of at least one RS of the candidate cell forat least one of BM or CSI reporting; ii) execute the cell switch to the candidate cell in response toa control message from the network node, wherein: the control message is based at least in part ona report comprising at least one L1 measurement for the respective CSI-RS of the candidate cell; and the at least one L1 measurement for the respective CSI-RS of the candidate cell is generatedbased at least in part on the at least one CSI-RS configuration for L1 measurement of the respectiveRS; iii) generate a combined set of configuration CSI-RSs based at least in part on the at least oneCSI-RS identifier of the first portion and the at least one CSI-RS identifier of the second portion;and iv) determine a subset of CSI-RSs of the candidate cell for at least one of BM or CSI reportingbased at least in part on: the combined set of CSI-RSs; and the respective CSI-RS configurationfor at least one of BM or CSI reporting. In the same example, the apparatus may also perform otheroperations and / or embody additional aspects of the above-described methods.

[0030] In various embodiments, as further described below, provided herein is a computer programproduct including at least one non-transitory computer-readable storage medium having computer-executable program code instructions stored therein, the computer-executable program codeinstructions including program code instructions configured for performing one or moreoperations and / or embody additional aspects of the above-described methods. For example, a computer program product may include at least one non-transitory computer-readable storage medium having computer-executable program code instructions stored therein, the computer-executable program code instructions including program code instructions configured to i) receive,from a network node, at least one CSI-RS configuration for a candidate cell, the at least one CSI-RS configuration comprising: a first portion comprising: at least one CSI-RS identifier for arespective RS of the candidate cell; and at least one CSI-RS configuration for L1 measurement ofthe respective RS of the candidate cell; and a second portion comprising: at least one CSI-RSidentifier for a second respective RS of the candidate cell; and a respective CSI-RS configurationof at least one RS of the candidate cell for at least one of BM or CSI reporting; ii) execute the cellswitch to the candidate cell in response to a control message from the network node, wherein: thecontrol message is based at least in part on a report comprising at least one L1 measurement forthe respective CSI-RS of the candidate cell; and the at least one L1 measurement for the respectiveCSI-RS of the candidate cell is generated based at least in part on the at least one CSI-RS configuration for L1 measurement of the respective RS; iii) generate a combined set ofconfiguration CSI-RSs based at least in part on the at least one CSI-RS identifier of the first portionand the at least one CSI-RS identifier of the second portion; and iv) determine a subset of CSI-RSsof the candidate cell for at least one of BM or CSI reporting based at least in part on: the combinedset of CSI-RSs; and the respective CSI-RS configuration for at least one of BM or CSI reporting.In the same example, the program code instructions may also be configured to perform additionaloperations and / or embody additional aspects of the above-described methods.

[0031] In various embodiments, as further described below, one or more operations of the above-described methods are performed by an apparatus having means for performing the one or more operations. For example, an apparatus may include i) means for receiving, from a network node, at least one CSI-RS configuration for a candidate cell, the at least one CSI-RS configuration comprising: a first portion comprising: at least one CSI-RS identifier for a respective RS of thecandidate cell; and at least one CSI-RS configuration for L1 measurement of the respective RS ofthe candidate cell; and a second portion comprising: at least one CSI-RS identifier for a second respective RS of the candidate cell; and a respective CSI-RS configuration of at least one RS ofthe candidate cell for at least one of BM or CSI reporting; ii) means for executing the cell switchto the candidate cell in response to a control message from the network node, wherein: the controlmessage is based at least in part on a report comprising at least one L1 measurement for the respective CSI-RS of the candidate cell; and the at least one L1 measurement for the respectiveCSI-RS of the candidate cell is generated based at least in part on the at least one CSI-RSconfiguration for L1 measurement of the respective RS; iii) means for generating a combined set of configuration CSI-RSs based at least in part on the at least one CSI-RS identifier of the firstportion and the at least one CSI-RS identifier of the second portion; and iv) means for determininga subset of CSI-RSs of the candidate cell for at least one of BM or CSI reporting based at least inpart on: the combined set of CSI-RSs; and the respective CSI-RS configuration for at least one ofBM or CSI reporting. In the same example, the apparatus may embody additional aspects and / or include additional means for performing additional operations of the above-described methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Having thus described certain example embodiments of the present disclosure in generalterms, reference will hereinafter be made to the accompanying drawings, which are not necessarilydrawn to scale, and wherein:

[0033] FIG.1 illustrates an example of a communication system in which an example embodimentof the present disclosure may be implemented;

[0034] FIG. 2 illustrates a block diagram of an apparatus that may be configured in accordance with an example embodiment of the present disclosure;

[0035] FIG. 3 illustrates an example CSI-RS configuration for LTM in accordance with at least anexample embodiment of the present disclosure;

[0036] FIG. 4 illustrates a signal diagram for CSI-RS-based LTM in accordance with an exampleembodiment of the present disclosure;

[0037] FIG. 5 illustrates an example CSI-RS configuration for LTM in accordance with at least anexample embodiment of the present disclosure;

[0038] FIG. 6 illustrates a signal diagram for CSI-RS-based LTM in accordance with an exampleembodiment of the present disclosure;

[0039] FIG. 7 is an example flowchart of a CSI-RS configuration signaling process in accordancewith at least an example embodiment of the present disclosure;

[0040] FIG. 8 is an example flowchart of a CSI-RS configuration signaling process in accordancewith at least an example embodiment of the present disclosure;

[0041] FIG. 9 is an example flowchart of a CSI-RS configuration signaling process in accordancewith at least an example embodiment of the present disclosure;

[0042] FIG. 10 illustrates a signal diagram for SSB-based LTM according to prior approaches.

[0043] FIG. 11 illustrates a diagram of radio resource control (RRC) configuration of LTMresource configuration and report configuration according to prior approaches;

[0044] FIG. 12 illustrates a diagram of LTM resource configuration given in RRC according to prior approaches; and

[0045] FIG. 13 illustrates a framework of CSI-RS configuration hierarchy according to priorapproaches. DETAILED DESCRIPTION

[0046] Some embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, variousembodiments may be embodied in many different forms and should not be construed as limited tothe embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elementsthroughout. As used herein, the terms “data,” “content,” “information,” and similar terms may beused interchangeably to refer to data capable of being transmitted, received and / or stored in accordance with the described embodiments. Thus, use of any such terms should not be taken to limit the spirit and scope of the embodiments.

[0047] Additionally, as used herein, the term ‘circuitry’ refers to (a) hardware-only circuit implementations (e.g., implementations in analog circuitry and / or digital circuitry); (b) combinations of circuits and computer program product(s) comprising software and / or firmware instructions stored on one or more computer readable memories that work together to cause anapparatus to perform one or more functions described herein; and (c) circuits, such as, for example,a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware foroperation even if the software or firmware is not physically present. This definition of ‘circuitry’applies to all uses of this term herein, including in any claims. As a further example, as used herein,the term ‘circuitry’ also includes an implementation comprising one or more processors and / orportion(s) thereof and accompanying software and / or firmware. As another example, the term‘circuitry’ as used herein also includes, for example, a baseband integrated circuit or applicationsprocessor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellularnetwork device, other network device (such as a core network apparatus), field programmable gatearray, and / or other computing device.

[0048] The term “comprising” means including but not limited to and should be interpreted in themanner it is typically used in the patent context. Use of broader terms such as comprises, includes,and having should be understood to provide support for narrower terms such as consisting of,consisting essentially of, and comprised substantially of. Furthermore, to the extent that the terms“includes” and “including,” and variants thereof are used in either the detailed description or the claims, these terms are intended to be inclusive in a manner similar to the term “comprising.”

[0049] The phrases “in one embodiment,” “according to one embodiment,” “in someembodiments,” “in various embodiments”, and the like generally refer to the fact that the particularfeature, structure, or characteristic following the phrase may be included in at least oneembodiment of the present disclosure, but not necessarily all embodiments of the presentdisclosure. Thus, the particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure such that these phrases do not necessarily refer to the same embodiment.

[0050] As used herein, the terms “example,” “exemplary,” and the like are used to mean “servingas an example, instance, or illustration.” Any implementation, aspect, or design described hereinas “example” or “exemplary” is not necessarily to be construed as preferred or advantageous overother implementations, aspects, or designs. Rather, use of the terms “example,” “exemplary,” andthe like are intended to present concepts in a concrete fashion.

[0051] If the specification states a component or feature “may,” “can,” “could,” “should,” “would,” “preferably,” “possibly,” “typically,” “optionally,” “for example,” “often,” or “might”(or other such language) be included or have a characteristic, that particular component or featureis not required to be included or to have the characteristic. Such component or feature may be optionally included in some embodiments, or it may be excluded.

[0052] As used herein, the term “computer-readable medium” refers to signal, non-transitorycomputer-readable medium and the like. The term ‘non-transitory computer-readable medium’refers to non-transitory storage hardware, non-transitory storage device or non-transitory computersystem memory that may be accessed by a controller, a microcontroller, a computational systemor a module of a computational system to encode thereon computer-executable instructions or software programs. A non-transitory “computer-readable medium” may be accessed by a computational system or a module of a computational system to retrieve and / or execute thecomputer-executable instructions or software programs encoded on the medium. Examples of non-transitory computer-readable media may include, but are not limited to, one or more types of hardware memory, non-transitory tangible media (for example, one or more magnetic storage disks, one or more optical disks, one or more USB flash drives), computer system memory or random-access memory (such as, DRAM, SRAM, EDO RAM), and the like.

[0053] As illustrated in FIG. 1, a communication network 100 is provided in accordance withvarious embodiments of the present disclosure. In some embodiments, the communication network100 is in communication with a plurality of user equipment (UE) 110. By way of example, the network 100 may be deployed within a radio access architecture based on long term evolution advanced (LTE Advanced, LTE-A) and / or new radio (NR, 5G). However, the system may be deployed in other network architectures including within other communication networks including, for example, other communication networks developed in the future, e.g., sixth generation (6G) networks, as well as any of a number of existing networks including a universal mobile telecommunications system (UMTS) radio access network (UTRAN, E-UTRAN or NG-RAN), wireless local area network (WLAN or WiFi), worldwide interoperability for microwaveaccess (WiMAX), Bluetooth®, personal communications services (PCS), ZigBee®, wideband code division multiple access (WCDMA), systems using ultra-wideband (UWB) technology, sensor networks, mobile ad-hoc networks (MANETs) and Internet Protocol multimedia subsystems (IMS) or any combination thereof.

[0054] The UE 110 may be any type of user terminal, terminal device, etc. to which resources onthe air interface are allocated and assigned. For example, the UE 110 may be a portable computingdevice such as a wireless mobile communication device including, but not limited to, the followingtypes of devices: a mobile station (mobile phone), smartphone, personal digital assistant (PDA),handset, device using a wireless modem (alarm or measurement device, etc.), laptop and / or touchscreen computer, tablet, game console, notebook, and multimedia device. The user equipment mayalso be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal oruser equipment (UE) just to mention but a few names or apparatuses.

[0055] The network 100 may include a plurality of network devices, such as a variety of networknodes 120 that serve one or more UEs 110. In some embodiments, the network node 120 includesa current serving cell 130 that is currently providing network services to one or more UEs 120.The current serving cell shown in the figures and described herein may also be referred to as adistributed unit, serving distributed unit, source unit, and / or the like. The current serving cellsdescribed herein may also be referred to as source cells. In some embodiments, the network nodeincludes one or more candidate cells that are not currently serving the UE 110 and embody acandidate target for serving one or more UE 110 (also referred to herein as a “candidate targetcell”). For example, the network node 120 may include candidate cells 140a, 140b that are notcurrently serving the UE 110. In various embodiments, the present disclosure provides improvedsystems and techniques for enabling the UE 110 to perform L1 candidate cell measurements usingCSI-RSs. For example, the present method, apparatus, and computer program product may provideone or more CSI-RS configurations to the UE 110. In doing so, the method, apparatus, andcomputer program product may enable the UE 110 to determine parameters for resource allocation,RS sequence, and / or the like for use in generating L1 measurements (e.g., L1-reference signalreceived power (RSRP), and / or the like). In various embodiments, the present method, apparatus,and computer program product are applicable to inter-network node scenarios in which one ormore candidate cells 140a, 140b belong to a different network node 120 (e.g., different gNodeB, and / or the like) as compared to the network node 120 of the current serving cell of the UE 110.

[0056] In some embodiments, a candidate cell 140a, 140b of the network node 120 uses the sameCSI-RSs for LTM measurement that are in use by the UE 110 connected to the candidate cell 140.In a respective candidate cell 140a, 140b, CSI-RSs are configured as UE-specific with narrower beams, shorter periodicity, and multiple frequency locations as compared to SSBs. As a result,there may be many CSI-RSs configured as compared to SSBs, which are cell-specific and always-on. Further, for LTM, a respective candidate cell configuration of a candidate cell 140a, 140b (e.g.,given under ServingCellConfig) may be provided to the UE 110 for application upon cell switchto the candidate cell 140a, 140b. In various embodiments, the provided configuration includes oneor more CSI-RS configurations for beam management (BM) purposes, CSI acquisition and / orreporting purposes, and / or the like. The provision of CSI-RS resource configurations for acandidate cell to a UE 110 may incur a significant overhead. In various embodiments, the presentdisclosure provides improved mechanisms for indicating CSI-RS configurations to a UE 110 thatminimize overall overhead associated with providing the CSI-RS configurations. For example, theUE 110 may carry out functionality shown in the signal diagrams 400, 600 as shown in FIGS. 4 and 6, respectively, and described herein. As another example, the UE 110 may carry out functionality shown in the flowcharts for processes 700, 800, 900 as shown in FIGS. 7, 8, and 9, respectively, and described herein.

[0057] The network node 120 and UE 110 may be configured to perform L1 measurement, cell switch, and post-cell switch BM, CSI reporting, and / or the like. For example, the network node120 and UE 110 may be configured to perform LTM cell switch. In various embodiments, LTMrefers to a cell switch procedure in which the serving cell of the UE 110 (e.g., a primary cell (PCell)or secondary cell (SCell)) is switched by the network 100 by sending an LTM cell switch command. In some embodiments, the LTM cell switch command embodies one or more control messages that are generated by the network node 120 and provisioned to the UE 110. In some embodiments, a control message embodies a medium access control element (MAC CE). For example, an LTM switch command may be delivered by MAC signaling using a MAC CE. In various embodiments, an LTM cell switch decision is based on measurements (e.g., L1 measurements) that are performed and reported by the UE 110 to the network node 120. Forexample, the UE 110 may provision an L1 measurement report to the network node 120 to causethe network 120 (e.g., or serving cell 130 thereof) to generate an LTM cell switch decision basedat least in part on the L1 measurement report. In some embodiments, measurements and reportingare based on a respective LTM candidate cell configuration provided by the network node for oneor more candidate cells 140a, 140b. In various embodiments, a candidate cell may refer to one ormore neighboring cells of a current serving cell. Additionally, in some embodiments, a candidatecell may refer to a current serving cell of a UE 110 (e.g., SCells and / or the like).

[0058] In legacy approaches, LTM measurements on a neighboring candidate cell 140a, 140b areperformed using SSBs transmitted by the candidate cell for which the SSB configuration is provided to the UE 110. In some embodiments, before the cell switch, the network node 120optionally activates one or more transmission configuration indication (TCI) states for one or morecandidate cells 140a, 140b. In some embodiments, in response to activation of a candidate cell TCIstate, the UE 110 tracks the time and / or frequency synchronization of the corresponding candidatecell using the reference signals associated with the one or more activated TCI states. In someembodiments, the UE 110 performs early UL synchronization before the cell switch (e.g., if requested or commanded to do so by the network node 120).

[0059] In an example signaling procedure for legacy SSB-based cell switching 1000 shown in FIG.10, the UE 110 may send a MeasurementReport message (e.g., a layer 3 measurement report) to thenetwork node 120 (signal 1001). The network node 120 may decide to configure LTM and initiateLTM preparation. The network node 120 may transmit an RRCReconfiguration message to the UE 110 including the SSB LTM candidate configurations (signal 1002). The UE 110 may store the SSB LTM candidate configurations and transmit an RRCReconfigurationComplete message to the network node 120 (signal 1003). The UE 110 may perform DL synchronization and UL synchronization with one or more candidate cells before receiving the cell switch command (operations 1004a, 1004b). The UE 110 may perform early timing advance (TA) acquisition with the one or more candidate cells as requested by the network node 110 before receiving the cell switch command. For example, the UE 110 may receive a physical downlink control channel (PDCCH) order from a serving cell that triggers contention free random access (CFRA), followingwhich the UE 110 may send a preamble towards the indicated candidate cell. To minimize the datainterruption of the serving cell due to CFRA towards one or more candidate cells, the UE 110 doesnot receive random access response from the network node 110 for the purpose of TA value acquisition. Instead, the TA value of the candidate cell may be indicated in the cell switch command (e.g., a MAC CE). The UE 110 may not maintain the TA timer for the candidate cell. Instead, the UE 110 may rely on network implementation to guarantee the TA validity.

[0060] Continuing the scenario, the UE 110 may perform SSB-based L1 measurements on the oneor more configured candidate cells and transmit SSB-based L1 measurement reports to the networknode 120 (signal 1005). The network node 120 may decide to execute cell switch to a target cell and transmits a cell switch command (e.g., MAC CE) triggering cell switch by including thecandidate configuration index of the target cell (signal 706). The UE 110 may switch to the targetcell and apply the configuration indicated by the candidate configuration index. If the UE 110 doesnot have valid TA of the target cell, the UE 110 may perform a random access channel (RACH)procedure towards the target cell (operation 1007). The UE 110 may complete the LTM cell switchprocedure by sending RRCReconfigurationComplete message to the target cell. If the UE 110 hasperformed a RACH procedure per operation 707, the UE 110 may consider that LTM cell switchexecution is successfully completed when the RACH procedure is successfully completed(operation 1008). For RACH-less LTM, the UE 110 may consider that LTM cell switch executionis successfully completed when the UE 110 determines that the network node 120 has successfullyreceived its first UL data.

[0061] In various embodiments, for LTM, information about measurement resources (e.g., SSBs)from LTM candidate cells 140a, 140b are provided to the UE 110 to enable the UE 110 to generatemeasurements. In some embodiments, the UE 110 is also configured with L1 measurementreporting configuration containing the UL resource information where the UE 110 may report themeasurements. For LTM, periodic and semi-persistent report on physical uplink control channel(PUCCH), semi-persistent report on physical upload shared channel (PUSCH), and aperiodicreport on PUSCH may be supported. In some embodiments, the UE 110 may be configured withone or more LTM CSI reporting configurations (e.g., LTM-CSI-ReportConfig) where a respectivereporting configuration contains an LTM CSI resource configuration (e.g., LTM-CSI-ResourceConfig) containing the information of resources to be used for channel measurements (e.g., L1-RSRP measurements). As shown in FIGS.11 and 12, an LTM resource configuration 1101, 1200 may contain SSBs from one or more candidate cells 140a, 140b. For each reporting configuration, the UE 110 may be configured to report M number of beams from each of the Lnumber of configured candidate cells. For example, a respective LTM CSI Resource Setting(LTM-CSI-ResourceConfig) may contain configuration of a LTM-CSI-SSB-ResourceSet, whichmay comprise of a list of Z ≥ 1 SS / PBCH blocks indices (e.g., given by ltm-CSI-SSB-ResourceList) and a list of Z LTM-CandidateIds (e.g., given by ltm-CandidateIDList) referring tocandidate cells associated with the synchronization signal (SS) / physical broadcast channel(PBCH) block indices. For a respective candidate cell 140a, 140b, the UE 110 may determine thetime domain behavior of a SS / PBCH block resource from ssb-Periodicity and ssb-PositionsInBurst. Further, the UE 110 may determine the frequency domain behavior of aSS / PBCH block resource by the higher layer parameters subCarrierSpacing, ssbFrequency.

[0062] For each candidate cell 140a, 140b, LTM CSI Report Configurations may be given undera configuration of current serving cell 130, where each report configuration contains an indicationof a LTM CSI Resource Config and other parameters related for reporting (e.g., timing and uplinkresources to transmit reports). An LTM CSI Resource configuration may contain a set of SSBindices from multiple candidate cells 140a, 140b, which may be placed in a common LTMconfiguration (e.g., in LTM-Config, as shown in the LTM resource configuration 1200 of FIG. 12). As shown in FIG. 12, a detailed configuration of a respective SSB of a candidate cell 140a,140b may be indicated in an LTM CSI Resource configuration given in LTM-SSB-Config underLTM-Candidate information element (IE). For each candidate cell 140a, 140b, LTM-Candidate IEmay contain the configuration / information that is used by the UE before the cell switch (e.g., SSBinformation for LTM measurements). The LTM-Candidate IE may also contain a list of NZP-CSI-RS resources that are currently used to provide the information for activation of TCI states associated with tracking RS (a type of CSI-RS). The same may be used for LTM measurements with CSI-RSs.

[0063] An LTM-Candidate IE may also include candidate cell configuration containing an RRC container (e.g., ServingCellConfig or CellGroupConfig) given by ltm-CandidateConfig thatcontains all the configuration details that will be used by the UE 110 after the UE 110 moves to acandidate cell (e.g., after the cell switch from the current serving cell 130). In other words, ltm-CandidateConfig given under LTM-Candidate IE may contain the configuration details needed toperform regular serving cell operation within the candidate cell 140a, 140b.

[0064] In various embodiments, LTM provides improvements in handover latency and interruption time as compared to layer 3-based mobility. However, existing approaches to LTM lack specificprocedures for supporting CSI-RS measurements to enable CSI-RS-based beam management andother physical layer operations on candidate cells (e.g., before or following LTM cell switch).

[0065] For serving cell procedures CSI-RS based measurements and reporting may be configuredfor serving cell beam management and CSI acquisition purpose. Beam management may be performed to select the appropriate beam and CSI acquisition (e.g., CSI reporting) may be performed to adapt the appropriate channel parameters (e.g., modulation, coding rate, etc.) for transmission and reception. Different types of CSI-RSs may be configured, i.e., periodic, semi- persistent, and aperiodic CSI-RSs. As shown in FIG. 13, a CSI-RS configuration may embody a framework of multi-level hierarchy including, in descending order of hierarchy, CSI- ResourceConfig 1301, non-zero-power (NZP)-CSI-RS-ResourceSet 1303, and NZP-CSI-RS- Resource 1305.

[0066] In various embodiments, the CSI-ResourceConfig 1301 defines a group of one or moreNZP-CSI-RS-ResourceSets 1303, CSI-IM-ResourceSets, CSI-SSB-ResourceSets, and / or the like.Table 1 provides example contents of a CSI-ResourceConfig 1303. Table 2 provides exampledescriptions of various fields of the CSI-ResourceConfig 1301. -- ASN1START-- TAG-CSI-RESOURCECONFIG-STARTCSI-ResourceConfig ::= SEQUENCE {csi-ResourceConfigId CSI-ResourceConfigId,csi-RS-ResourceSetList CHOICE {nzp-CSI-RS-SSB SEQUENCE {nzp-CSI-RS-ResourceSetList SEQUENCE (SIZE (1..maxNrofNZP-CSI-RS-ResourceSetsPerConfig)) OF NZP-CSI-RS-ResourceSetId OPTIONAL, --Need Rcsi-SSB-ResourceSetList SEQUENCE (SIZE (1..maxNrofCSI-SSB-ResourceSetsPerConfig)) OF CSI-SSB-ResourceSetId OPTIONAL -- Need R}, csi-IM-ResourceSetList SEQUENCE (SIZE (1..maxNrofCSI-IM-ResourceSetsPerConfig)) OF CSI-IM-ResourceSetId }, bwp-Id BWP-Id,resourceType ENUMERATED { aperiodic, semiPersistent, periodic },..., [[ csi-SSB-ResourceSetListExt-r17 CSI-SSB-ResourceSetIdOPTIONAL -- Need R]] } -- TAG-CSI-RESOURCECONFIG-STOP-- ASN1STOPTable 1. Example CSI-ResourceConfig IECSI-ResourceConfig field descriptionsbwp-Id: The downlink bandwidth part (DL BWP) which the CSI-RS associated with this CSI-ResourceConfig are located in. csi-IM-ResourceSetList: List of references to CSI-IM resources used for CSI measurement and reporting in a CSI-RSresource set. Contains up to maxNrofCSI-IM-ResourceSetsPerConfig resource sets if resourceType is 'aperiodic' and 1 otherwise. csi-ResourceConfigId:Used in CSI-ReportConfig to refer to an instance of CSI-ResourceConfig.csi-SSB-ResourceSetList, csi-SSB-ResourceSetListExt:List of references to SSB resources used for CSI measurement and reporting in a CSI-RS resource set. The csi-SSB-ResourceSetListExt provides additional references and can only be configured if csi-SSB-ResourceSetList is configured and groupBasedBeamReporting-v1710 isconfigured in the CSI-ReportConfig that indicates this CSI-ResourceConfig as resourcesForChannelMeasurement. If groupBasedBeamReporting-v1710 is configured in the IE CSI-ReportConfig that indicates this CSI-ResourceConfig as resourceForChannelMeasurement, the network configures 2 resource sets, which may be two NZP CSI-RS resource sets, two CSI SSB resource sets or one NZP CSI-RS resource set and one CSI-SSB resource set. -if the list has one CSI-SSB resource set, this resource set is indicated by a resource setindicator set to 1, while the resource set indicator of the NZP CSI-RS resource set is 0; -if the list has two CSI-SSB resource sets, the first resource set is indicated by a resource setindicator set to 0 and the second resource set by a resource set indicator set to 1.nzp-CSI-RS-ResourceSetList: List of references to NZP CSI-RS resources used for beam measurement and reporting in aCSI-RS resource set. If resourceType is set to 'aperiodic', the network configures up to maxNrofNZP-CSI-RS- ResourceSetsPerConfig resource sets. If resourceType is set to 'periodic' or 'semiPersistent' and groupBasedBeamReporting-v1710 is not configured in IE CSI-ReportConfig, the networkconfigures 1 resource set. If resourceType is set to 'periodic' or 'semiPersistent' and groupBasedBeamReporting-v1710 is configured, the network configures 2 resource sets, which may be two NZP CSI-RS resource sets, two CSI SSB resource sets or one NZP CSI-RSresource set and one CSI-SSB resource set. -if the list has one NZP CSI-RS resource set, this resource set is indicated by a resource setindicator set to 0; -if the list has two NZP CSI-RS resource sets, the first resource set is indicated by a resourceset indicator set to 0 and the second resource set by a resource set indicator set to 1.resourceType: Time domain behavior of resource configuration. It does not apply to resources provided in thecsi-SSB-ResourceSetList.Table 2. Example CSI-ResourceConfig Fields

[0067] In various embodiments, an NZP-CSI-RS-ResourceSet 1303 is a set of NZP-CSI-RS resources (e.g., respective identifiers thereof) and set-specific parameters. Table 3 provides example contents of an NZP-CSI-RS-ResourceSet 1303. Table 3 provides example descriptions of various fields of the NZP-CSI-RS-ResourceSet 1303. -- ASN1START-- TAG-NZP-CSI-RS-RESOURCESET-STARTNZP-CSI-RS-ResourceSet ::= SEQUENCE {nzp-CSI-ResourceSetId NZP-CSI-RS-ResourceSetId,nzp-CSI-RS-Resources SEQUENCE (SIZE (1..maxNrofNZP-CSI-RS-ResourcesPerSet)) OF NZP-CSI-RS-ResourceId, repetition ENUMERATED { on, off }OPTIONAL, -- Need SaperiodicTriggeringOffset INTEGER(0..6)OPTIONAL, -- Need Strs-Info ENUMERATED {true}OPTIONAL, -- Need R..., [[ aperiodicTriggeringOffset-r16 INTEGER(0..31)OPTIONAL -- Need S]], [[ pdc-Info-r17 ENUMERATED {true}OPTIONAL, -- Need RcmrGroupingAndPairing-r17 CMRGroupingAndPairing-r17OPTIONAL, -- Need RaperiodicTriggeringOffset-r17 INTEGER (0..124)OPTIONAL, -- Need SaperiodicTriggeringOffsetL2-r17 INTEGER(0..31)OPTIONAL -- Need R]] } CMRGroupingAndPairing-r17 ::= SEQUENCE {nrofResourcesGroup1-r17 INTEGER (1..7),pair1OfNZP-CSI-RS-r17 NZP-CSI-RS-Pairing-r17OPTIONAL, -- Need Rpair2OfNZP-CSI-RS-r17 NZP-CSI-RS-Pairing-r17OPTIONAL -- Need R} NZP-CSI-RS-Pairing-r17 ::= SEQUENCE {nzp-CSI-RS-ResourceId1-r17 INTEGER (1..7),nzp-CSI-RS-ResourceId2-r17 INTEGER (1..7)} -- TAG-NZP-CSI-RS-RESOURCESET-STOP-- ASN1STOPTable 3. Example NZP-CSI-Resource Set IE.NZP-CSI-RS-ResourceSet field descriptionsaperiodicTriggeringOffset, aperiodicTriggeringOffset-r16, aperiodicTriggeringOffset-r17: Offset X between the slot containing the DCI that triggers a set of aperiodic NZP CSI-RS resources and the slot in which the CSI-RS resource set is transmitted. For aperiodicTriggeringOffset, the value 0 corresponds to 0 slots, value 1 corresponds to 1 slot,value 2 corresponds to 2 slots, value 3 corresponds to 3 slots, value 4 corresponds to 4 slots,value 5 corresponds to 16 slots, value 6 corresponds to 24 slots. For aperiodicTriggeringOffset-r16 and aperiodicTriggeringOffset-r17, the value indicates thenumber of slots. aperiodicTriggeringOffset-r17 is applicable to SCS 480 kHz and 960 kHz,and only the values of integer multiples of 4 are valid, i.e. 0, 4, 8, and so on. The networkconfigures only one of the fields. When neither field is included, the UE applies the value 0.aperiodicTriggeringOffsetL2:Indicates triggering offset of aperiodic NZP CSI-RS resources used for fast activation of thesecondary cell (SCell), when the NZP CSI-RS resources are activated by the MAC CE. Thevalue indicates the number of slots. cmrGroupingAndPairing: Configures codec mode request (CMR) groups and pairs. The first nrofResourcesGroup1 resources in the NZP-CSI-RS resource set belong to Group 1 and the remaining resources in the NZP-CSI-RS resource set belong to Group 2. nrofResourcesGroup1 is ^1 and the numberof remaining resources in the NZP-CSI-RS resource set belonging to Group 2 is ^2. Maximumtotal number in Group 1 and Group 2 is 8.pair1OfNZP-CSI-RS, pair2OfNZP-CSI-RS:A pair of NZP CSI-RS resources. In one pair, one resource shall belong to group 1 and theother resource shall belong to group 2 as configured by nrofResourcesGroup1 and nrofResourcesGroup2. nzp-CSI-RS-Resources:NZP-CSI-RS-Resources associated with this NZP-CSI-RS resource set. For CSI, there are atmost 8 NZP CSI RS resources per resource set.nzp-CSI-RS-ResourceId1, nzp-CSI-RS-ResourceId2:The nzp-CSI-RS-ResourceId1-r17 represents the index of the NZP CSI-RS resource inResource Group 1, and nzp-CSI-RS-ResourceId2-r17 represents the index of the NZP CSI-RSresource in Resource Group 2. pdc-Info: Indicates that this NZP-CSI-RS-ResourceSet, if configured also with trs-Info, is used for propagation delay compensation. The field can be present only if trs-info is present. The field can be present in only one NZP-CSI-RS-ResourceSet. If network configures this field for anNZP-CSI-RS-ResourceSet, the UE measures the UE Rx-Tx time difference based on resourcesconfigured in this resource set.repetition:Indicates whether repetition is on / off. If the field is set to off or if the field is absent, the UEmay not assume that the NZP-CSI-RS resources within the resource set are transmitted withthe same downlink spatial domain transmission filter. It can only be configured for CSI-RSresource sets which are associated with CSI-ReportConfig with report of L1 RSRP, L1 SINRor "no report".trs-Info: Indicates that the antenna port for all NZP-CSI-RS resources in the CSI-RS resource set issame. If the field is absent or released the UE applies the value false.Table 4. Example NZP-CSI-RS-ResourceSet Fields

[0068] In various embodiments, an NZP-CSI-RS-Resource 1305 is used to configure NZP-CSI- RS transmitted in the cell where the IE is included, which the UE 110 may be configured tomeasure on. A change of configuration between periodic, semi-persistent or aperiodic for an NZP-CSI-RS-Resource may not be supported without a release and add. Table 5 provides example contents of an NZP-CSI-RS-Resource 1305. Table 6 provides example descriptions of various fields of the NZP-CSI-RS-Resource 1305. -- ASN1START-- TAG-NZP-CSI-RS-RESOURCE-STARTNZP-CSI-RS-Resource ::= SEQUENCE {nzp-CSI-RS-ResourceId NZP-CSI-RS-ResourceId,resourceMapping CSI-RS-ResourceMapping,powerControlOffset INTEGER (-8..15),powerControlOffsetSS ENUMERATED{db-3, db0, db3, db6}OPTIONAL, -- Need RscramblingID ScramblingId,periodicityAndOffset CSI-ResourcePeriodicityAndOffset OPTIONAL,-- Cond PeriodicOrSemiPersistentqcl-InfoPeriodicCSI-RS TCI-StateId OPTIONAL, -- CondPeriodic ... } -- TAG-NZP-CSI-RS-RESOURCE-STOP-- ASN1STOPTable 5. Example NZP-CSI-RS-Resource IENZP-CSI-RS-Resource field descriptionsperiodicityAndOffset: Periodicity and slot offset sl1 corresponds to a periodicity of 1 slot, sl2 to a periodicity of twoslots, and so on. The corresponding offset is also given in number of slots. Network always configures the UE with a value for this field for periodic and semi-persistent NZP-CSI-RS- Resource (as indicated in CSI-ResourceConfig).powerControlOffset: Power offset of PDSCH RE to NZP CSI-RS resource element (RE). Value in decibels (dB).powerControlOffsetSS: Power offset of NZP CSI-RS RE to SSS RE. Value in dB.qcl-InfoPeriodicCSI-RS: For a target periodic CSI-RS, contains a reference to one TCI-State in TCI-States for providing the QCL source and QCL type. For periodic CSI-RS, the source can be SSB or another periodic-CSI-RS. Refers to the TCI-State or dl-OrJoint-TCI-State which has this valuefor tci-StateId and is defined in tci-StatesToAddModList or in dl-OrJointTCI-StateList in the PDSCH-Config included in the BWP-Downlink corresponding to the serving cell and to the DL BWP to which the resource belongs to. resourceMapping: OFDM symbol location(s) in a slot and subcarrier occupancy in a PRB of the CSI-RSresource. scramblingID: Scrambling identifier.Conditional Presence ExplanationPeriodic The field is optionally present, Need M, for periodic NZP-CSI-RS-Resources (as indicated in CSI-ResourceConfig). The fieldis absent otherwise.PeriodicOrSemiPersistent The field is optionally present, Need M, for periodic and semi-persistent NZP-CSI-RS-Resources (as indicated in CSI- ResourceConfig). The field is absent otherwise.Table 6. Example NZP-CSI-RS-Resource Fields

[0069] As described herein, the use of SSB-based L1 measurements to evaluate candidate cell quality for cell switch decisions may demonstrate drawbacks as compared to CSI-RS measurements due to the narrower bandwidth, longer periodicity, and wider beams required to generate the SSB measurements. For example, CSI-RS measurements may support the use ofnarrower beams over larger bandwidth and shorter periodicity as compared to SSB measurements.In doing so, the CSI-RS-based approach may achieve greater time and frequency synchronizationwith the target cell as compared to SSB-based approaches. However, existing signaling techniqueslack efficient means for providing the configuration of CSI-RS resources to a UE for enablementof L1 measurements on a candidate cell. As a result, the provisioning of CSI-RS configurationsmay incur a significant overhead. In various embodiments, the present methods, apparatuses, andcomputer program products overcome this challenge, and others, by introducing novel signaling techniques for provisioning the CSI-RS configuration for a candidate cell to a UE 110.

[0070] For example, the present method, apparatus, and computer program product may include provisioning of the CSI-RS configuration for a candidate cell as two parts or portions. The first portion of the CSI-RS configuration may be provisioned to the UE 110 outside of the candidatecell RRC configuration (e.g., under LTM-Candidate IE, but not within ltm-CandidateConfig). Forexample, the first portion of the CSI-RS configuration may be provisioned for the LTM L1measurement configuration. The second portion of the CSI-RS configuration may be provisionedto the UE 110 in the candidate cell configuration (e.g., the serving cell configuration for beammanagement and other CSI acquisition, including CSI reporting), which is applied and / or decodedby the UE 110 upon cell switch. For example, the second portion of the CSI-RS configuration maybe given within the candidate cell configuration (e.g., ltm-CandidateConfig under LTM-CandidateIE). From the UE perspective, two sets of CSI-RS configurations may be provided to the UE 110.The two sets of CSI-RS configurations may include a first set of CSI-RS configurations for LTMunder LTM Candidate IE and a second set of CSI-RS configurations in in candidate cellconfiguration (e.g., given by ServingCellConfig or CellGroupConfig within a RRC container ofthe candidate cell given by ltm-CandidateConfig), which is typically decoded upon LTM cellswitch. In various embodiments, when the CSI-RS configuration for candidate cell is divided intotwo portions as indicated above, the report configuration for beam management after cell switchmay refer to the resource configurations maintained outside the candidate configuration. In doingso, overhead of CSI-RS configuration provisioning may be minimized (e.g., due to efficiency ofreferring back to information already possessed by the UE 110). Example approaches to the two-portion provision of CSI-RS configurations are further shown in FIGS.3-9 and described herein.

[0071] FIG. 2 shows example apparatuses 200a, 200b according to one embodiment. Theapparatuses 200a, 200b may be embodiments of network devices or may be embodied by orotherwise associated with one or more network devices. For example, the apparatus 200a may beembodied by a UE 110 and the apparatus 200b may be embodied as a network node 120, or one or more elements thereof (e.g., serving cell, centralized unit, candidate cell, and / or the like).

[0072] Regardless of the device that embodies the apparatus 200a (or 200b), the apparatus mayinclude processor 202a (202b), memory 204a (204b), and network interface 206a (206b). Theapparatuses 200a, 200b may be configured to execute the operations described herein, including operations for carrying out operations for obtaining, generating, and / or determining the CSI-RSconfigurations shown in FIGS. 3 and 5, respectively, and described herein. For example, theapparatuses 200a, 200b may be configured to execute functionality shown in the signalingdiagrams 400, 600 shown in FIGS.4 and 6 and described herein. As another example, the apparatus200b may be configured to perform the processes 700, 800, 900 shown in FIGS. 7, 8, and 9,respectively, and described herein. The apparatus 200b may embody functionality performed by anetwork node 120 in execution of one or more operations of the processes 700, 800, 900Althoughthese components are described with respect to the performance of various functions, it should beunderstood that the particular implementations necessarily include the use of particular hardware.It should also be understood that certain of these components may include similar or commonhardware. For example, two sets of circuitries may both leverage use of the same processor,network interface, storage medium, or the like to perform their associated functions, such thatduplicate hardware is not required for each set of circuitries. The proceeding description of the processor 202a, 204a, and network interface 206a of the apparatus 200a may apply to similarly named elements of the apparatus 200b (e.g., processor 202b, 204b, and network interface 206b).

[0073] In some embodiments, the processor 202a (and / or co-processor or any other processingcircuitry assisting or otherwise associated with the processor) may be in communication with thememory 204a via a bus for passing information among components of the apparatus. The memory204a is non-transitory and may include, for example, one or more volatile and / or non-volatilememories. In other words, for example, the memory 204a may be an electronic storage device(e.g., a non-transitory computer-readable storage medium). The memory 204a may be configuredto store information, data, content, applications, instructions, or the like for enabling the apparatusto carry out various functions in accordance with an example embodiment disclosed herein. For example, the memory 204a may store identifiers for one or more serving cells, candidate cells,CSI-RS resource sets (e.g., SP resource sets and / or the like), TCI states, bandwidth parts (BWPs),logic channel identifiers, and / or the like. As another example, the memory 204a may store CSI- RS resource sets, control messages, and / or the like.

[0074] The processor 202a may be embodied in a number of different ways and may, for example,include one or more processing devices configured to perform independently. In some non-limitingembodiments, the processor 202a may include one or more processors configured in tandem via abus to enable independent execution of instructions, pipelining, and / or multithreading. The use ofthe term “processor” may be understood to include a single core processor, a multi-core processor,multiple processors internal to the apparatus, and / or remote or “cloud” processors.

[0075] In some embodiments, the processor 202a may be configured to execute instructions storedin the memory 204a and / or circuitry otherwise accessible to the processor 202a. In some embodiments, the processor 202a may be configured to execute hard-coded functionalities. As such, whether configured by hardware or software methods, or by a combination thereof, the processor 202a may represent an entity (e.g., physically embodied in circuitry) capable ofperforming operations according to an embodiment disclosed herein while configured accordingly.Alternatively, as another example, when the processor 202a is embodied as an executor of softwareinstructions, the instructions may specifically configure the processor 202a to perform the algorithms and / or operations described herein when the instructions are executed.

[0076] In some embodiments, the apparatus 200a may optionally include input / output circuitrythat may, in turn, be in communication with processor 202a to provide output to a user and / or otherentity and, in some embodiments, to receive an indication of an input. The input / output circuitrymay comprise a user interface and may include a display, and may comprise a web user interface,a mobile application, a query-initiating computing device, a kiosk, or the like. In someembodiments, the input / output circuitry may also include a keyboard, a mouse, a joystick, a touchscreen, touch areas, soft keys, a microphone, a speaker, or other input / output mechanisms. The processor and / or user interface circuitry comprising the processor may be configured to control one or more functions of one or more user interface elements through computer programinstructions (e.g., software and / or firmware) stored on a memory accessible to the processor (e.g.,memory 204a, and / or the like).

[0077] The network interface 206a may be any means such as a device or circuitry embodied in either hardware or a combination of hardware and software that is configured to receive and / or transmit data from / to a network and / or any other device, circuitry, or module in communication with the apparatus 200a. In this regard, the network interface 206a may include, for example, anetwork interface for enabling communications with a wired or wireless communication network,such as the application function (AF), multicast and broadcast service function (MBSF), multicastand broadcast user plane function (MB-UPF), and / or multicast and broadcast session managementfunction (MB-SMF). For example, the network interface 206a may include one or more network interface cards, antennae, buses, switches, routers, modems, and supporting hardware and / or software, or any other device suitable for enabling communications via a network. Additionally,or alternatively, the network interface 206a may include the circuitry for interacting with theantenna / antennae to cause transmission of signals via the antenna / antennae or to handle receipt ofsignals received via the antenna / antennae.

[0078] FIG. 3 illustrates an example of CSI-RS configuration 300 for LTM in accordance with atleast an example embodiment of the present disclosure. In a first approach to the two-part provisionof CSI-RS configuration to a UE 110, the UE 110 may be configured to refer a first portion 301 (e.g., outside the candidate cell configuration) or a second portion 303 (e.g., CSI-RS resources within candidate cell configuration). In some embodiments, configuration information of one or more CSI-RS resources, resource sets, resource configurations, and / or the like (e.g., each with a respective identifier) for a candidate cell is / are provided to the UE for LTM measurements. In some embodiments, the UE 110 is configured to expect that measurement RSs for a LTM CSI reporting may point to CSI-RSs provided for LTM measurements. Additionally, in some embodiments, configuration of one or more CSI-RSs (e.g., each with a respective identifier) for the candidate cell is provided to the UE 110 under the candidate cell configuration (e.g.,ServingCellConfig), which is used by the UE 110 after switching to the candidate cell. In variousembodiments, after the cell switch to the candidate cell, the UE 110 is configured to expect that measurement RSs for a CSI reporting for serving cell procedure (e.g., intra / inter-cell beammanagement, CSI acquisition, etc.) within the candidate cell may point to either CSI-RSs providedfor LTM measurements or CSI-RSs provided under candidate cell configuration (e.g., ServingCellConfig).

[0079] In one example, configuration of one or more CSI-RSs for a candidate cell for LTM measurements may be provided under LTM Candidate IE, but outside of candidate cell configuration (e.g., ServingCellConfig) associated with the candidate cell. In another example, configuration of CSI-RSs (e.g., each with a respective identifier) for serving cell procedure (e.g.,intra / inter-cell beam management, CSI acquisition, and / or the like) within the candidate cell maybe provided under candidate cell configuration (e.g., ServingCellConfig) associated with the candidate cell. In another example, the UE 110 may be instructed to expect that a LTM CSIResource Config, associated with a LTM CSI Report Config, is formed as a list of indices pointingto CSI-RSs given for LTM measurements (under LTM Candidate IE outside candidate cell configuration (e.g., ServingCellConfig)). In still another example, the UE 110 may be instructed to expect that, after the cell switch, a CSI Resource Config, associated with a CSI Report Configfor serving cell procedure (e.g., intra / inter-cell beam management, CSI acquisition, and / or thelike), is formed as list of indices pointing to the either CSI-RSs given for LTM measurements(under LTM Candidate IE outside candidate cell configuration (e.g., ServingCellConfig)) or CSI-RSs given under candidate cell configuration (e.g., ServingCellConfig).

[0080] In some embodiments, a CSI Report Config or a CSI Resource Config for serving cell procedure (e.g., intra / inter-cell beam management, CSI acquisition, etc.), may further indicate whether to refer the CSI-RSs given for LTM measurements (under LTM Candidate IE outside candidate cell configuration (e.g., ServingCellConfig)) or CSI-RSs given under candidate cell configuration (e.g., ServingCellConfig). In some embodiments, CSI-RS identifiers (at resource configuration, resource set, or resource level) in the first portion of the configuration (for LTM measurements under LTM Candidate IE outside candidate cell configuration (e.g., ServingCellConfig)) and in the second portion of the configuration (for serving cell proceduregiven under candidate cell configuration (e.g., ServingCellConfig)) may share the same ID space.

[0081] In some embodiments, if there is a CSI-RS or CSI Resource Set or CSI Resource Configgiven in second portion of the configuration candidate cell configuration (e.g., ServingCellConfig)and it has same identifier as given in the first portion of the configuration, the UE 110 applies theconfiguration under the identifier listed in the second portion of the configuration when applying the first and second configuration. Alternatively, in some embodiments, if there is a CSI-RS or CSI Resource Set or CSI Resource Config given in the second portion of the configuration candidate cell configuration (e.g., ServingCellConfig) and it has same identifier as given in the first portion of the configuration, the UE 110 applies the configuration under the identifier listedin the first portion of the configuration when applying the first and second configuration. In someembodiments, the UE 110 is instructed by the network node 120 whether to apply the first portionor the second portion in the scenario of same identifier.

[0082] In some embodiments, the UE 110 may indicate to the network node 120 a capability ofsupporting configuration of CSI-RS in multiple parts (e.g., in first and second part). For example,the UE 110 may indicate to the network node 120 capability for supporting multi-portion CSI-RSconfiguration (for LTM). In some embodiments, the UE 110 indicates this capability in terms of number of candidate cells this operation can be supported. In some embodiments, the capabilitymay be provisioned to each candidate distributed unit (DU) (e.g., via serving centralized unit (CU))to build report configurations and their association with resource configurations accordingly. Insome embodiments, in case of inter-CU scenarios, the serving CU may send this capability to candidate CU and then candidate CU may forward this to each of its candidate DU.

[0083] In some embodiments, the network node (e.g., serving CU or serving DU) may configure the UE 110 to perform such operation of using CSI-RSs for LTM measurements also for servingcell measurements after the cell switch. For example, the performance of the operation may be asa candidate cell specific configuration (e.g., configured per candidate cell under LTM Candidate information element). In instances of disaggregated architecture, the indication to perform suchoperations may be signaled to the UE 110 by each DU (e.g., via serving / candidate CU) preparingand providing the configuration during the preparation phase. In some embodiments, the UE behavior of using CSI-RSs for LTM measurements also for serving cell measurements after the cell switch may be predefined in the standard.

[0084] An example of the first procedure is shown in the signaling diagram 400 of FIG. 4. In thisexample, the RRC Reconfiguration (Reconfig) for a candidate cell 140 (candidate DU – DU2) ofthe UE is provided with NZP-CSI-RS 1, NZP-CSI-RS 4, NZP-CSI-RS 6 and respective configuration for LTM measurements, and then NZP-CSI-RS 2, NZP-CSI-RS 3, NZP-CSI-RS 5 and respective configuration are provided under candidate cell configuration (e.g., under ServingCellConfig) (signal 401). Before the cell switch, according to the LTM reporting configuration, the UE 110 only considers the CSI-RSs for measurement and LTM CSI reporting configured for LTM measurements (operation 403, signal 405, signal 407). After the cell switch,when the UE 110 moves to DU2 (e.g., candidate cell 140), the UE 110 decodes the candidate cellconfiguration and, according to the CSI reporting configuration, considers the both CSI-RSsconfigured for LTM measurements and also CSI-RSs given under candidate cell configuration formeasurement used for serving cell procedures (operation 409, signal 411).

[0085] In an example scenario, the UE 110 may receive from a network node 120 one or moreconfigurations, a respective configuration including i) a set of L1 measurement configurations fora first set of NZP-CSI-RSs of a candidate cell, ii) a candidate cell configuration with a second setof NZP-CSI-RSs of the candidate cell. The UE 110 may generate a set of L1 measurements of thefirst set of NZP-CSI-RSs based at based at least in part on the set of L1 measurementconfigurations. The UE 110 may provision to the network node a report comprising the set of L1measurements. The UE 110 may execute a cell switch to the candidate cell in response to a controlmessage form the network node, where the control message is based at least in part on the reportcomprising the set of L1 measurements. The UE 110 may generate a set of BM L1 measurementsand / or CSI L1 measurements of the second set of NZP-CSI-RSs and the first set of NZP-CSI-RSsbased at least in part on the set of candidate cell configuration and the set of L1 measurement configurations. The UE 110 may provision to the candidate cell the set of BM or CSI L1 measurements to cause the candidate cell to perform BM or CSI adaptation based at least in part on the set of BM L1 measurements and / or CSI L1 measurements.

[0086] FIG. 5 illustrates an example CSI-RS configuration 500 for LTM. In a second approach tothe two-part provision of CSI-RS configuration to a UE 110, after the UE 110 is switched (or switches) to the target candidate cell, the UE 110 combines the first and second portion of the configuration, and applies the combined set of parts for measurements used in serving cell operations on the target candidate cell (e.g., BM, CSI acquisition, and / or the like).

[0087] For example, the configuration information of one or more CSI-RSs (e.g., each with arespective identifier) for a candidate cell may be provided to the UE 110 for LTM measurements.In various embodiments, the UE 110 is configured to expect that measurement RSs for a LTM CSIreporting may point to CSI-RSs provided for LTM measurements. In some embodiments, configuration of one or more CSI-RSs (e.g., each with a respective identifier) for the candidate cell is provided to the UE 110 under the candidate cell configuration (e.g., ServingCellConfig), the configuration which is used by the after the UE 110 moves to the candidate cell. In someembodiments, after the cell switch to the candidate cell, the UE 110 merges or combines the set ofCSI-RSs given for LTM measurements for the candidate cell and set of CSI-RSs under thecandidate cell configuration of the candidate cell into a combined set of configuration CSI-RSs505. In some embodiments, the UE 110 is configured to expect that measurement RSs for a CSIreporting for serving cell procedure (e.g., intra / inter-cell beam management, CSI acquisition, etc.)within the candidate cell may point to CSI-RSs from the combined set of configuration CSI-RSs 505.

[0088] In some embodiments, one or more CSI-RS identifiers (e.g., at resource configuration, resource set, or resource level) in the first portion 501 of the configuration (e.g., for LTM measurements under LTM Candidate IE outside candidate cell configuration (e.g.,ServingCellConfig)) and in the second portion 503 of the configuration (for serving cell proceduregiven under candidate cell configuration (e.g., ServingCellConfig)) may share the same ID space.As one example, the CSI-RS, CSI Resource Set, or CSI Resource Config of both first and secondmay be combined under the same ID space. In some embodiments, if there is a CSI-RS or CSIResource Set or CSI Resource Config given in second portion 503 of the configuration candidatecell configuration (e.g., ServingCellConfig) and it has same identifier as given in the first portion501 of the configuration, the UE 110 applies the configuration under the identifier listed in thesecond portion 503 of the configuration when combining the first and second configurations 501,503. In other words, the candidate cell CSI-RS configuration of the second configuration 503 mayoverride or replace the CSI configuration (identifier) of the first configuration 501 when combined.

[0089] Alternatively, in some embodiments, if there is a CSI-RS or CSI Resource Set or CSIResource Config given in the second portion 503 of the configuration candidate cell configuration(e.g., ServingCellConfig) and it has same identifier as given in the first portion 501 of the configuration, the UE 110 applies the configuration under the identifier listed in the first portion 501 of the configuration when combining the first and second configurations 501, 503. In otherwords, the CSI configuration (identifier) of the first configuration 501 may override or replace theCSI configuration (identifier) of candidate cell CSI-RS configuration when combined. In variousembodiments, UE 110 receives an instruction (e.g., control message and / or the like) that indicateswhich configuration to consider when the same identifier is used in first and second parts 501, 503.

[0090] In some embodiments, the second portion 503 of the configuration may comprise of a reference to the first portion 501 of the configuration (e.g., an identifier reference to the first portion501 of the configuration). The reference may one of a CSI-RS resource identifier, CSI-RS ResourceSet identifier, CSI-RS Resource Config identifier, and / or the like. In some embodiments, thereference identifier in the second portion 503 of the configuration may not contain any other parameters than the resource identifier. When reference identifier is given in the second portion 503 of the configuration, the corresponding parameters of the same identifier in the first portion503 of the configuration may be applied for the combination configuration. In other words, whenRS identifier is given in the second portion 503, the corresponding parameters of the RS may bedetermined form the configuration given in first portion 503 associated with the same RS identifier.

[0091] In some embodiments, for a CSI-RS (or CSI Resource Set or CSI Resource Config) givenfor LTM measurements, a one-bit explicit indication is provided by the network node 120 to the UE 110 to indicate whether or not such resource or resource set or resource config may be considered for serving cell measurement after the cell switch. In some embodiments, the UE 110only considers the CSI-RSs for combining with the CSI-RSs in the candidate cell configurationfor which it is indicated that the resource may be considered for serving cell measurement afterthe cell switch. In some embodiments, the UE 110 may not consider the CSI-RSs for combiningwith the CSI-RSs in the candidate cell configuration for which it is indicated that the resource maynot be considered for serving cell measurement after the cell switch. In some embodiments, in instances of disaggregated architecture, the one-bit indication is signaled by each DU (e.g., candidate cell) preparing and providing the configuration during the preparation phase.

[0092] In some embodiments, the UE 110 indicates to the network node 120 its capability of supporting such operation of using CSI-RSs for LTM measurements, combining them with the CSI-RSs given in the candidate cell configuration, and using the combined set of configuration CSI-RSs for serving cell measurements after the cell switch. For example, the UE may indicatesuch capability in terms of number of candidate cells for which this operation may be supported.As another example, in instances of disaggregated architecture, such capability may be communicated to each DU (e.g., via serving / candidate CU) preparing and providing the configuration during the preparation phase.

[0093] In some embodiments, the network node 120 (e.g., serving CU or serving DU) may configure the UE 110 to perform such operation of using CSI-RSs for LTM measurements, combining them with the CSI-RSs given in the candidate cell configuration, and using the combined set of configuration CSI-RSs for serving cell measurements after the cell switch. Forexample, the UE 110 may be configured to perform the operation on a candidate cell-specific basis(e.g., configured per candidate cell under LTM Candidate information element). As another example, in instances of disaggregated architecture, the instruction to perform the operation may be signaled to the UE 110 by each DU (e.g., via serving / candidate CU) preparing and providingthe configuration during the preparation phase. In another example, the UE behavior of using CSI-RSs for LTM measurements also for serving cell measurements after the cell switch may be predefined in the standard.

[0094] An example of the second approach is shown in the signaling diagram 600 of FIG. 6. Inthis example, the RRC Reconfiguration (Reconfig) for a candidate cell 140 (candidate DU – DU2)of the UE is provided with NZP-CSI-RS 1, NZP-CSI-RS 4, NZP-CSI-RS 6 and respective configuration for LTM measurements, and then NZP-CSI-RS 2, NZP-CSI-RS 3, NZP-CSI-RS 5 and respective configuration are provided under candidate cell configuration (e.g., underServingCellConfig) (signal 601). Before the cell switch, according to the LTM reportingconfiguration, the UE 110 only considers the CSI-RSs for measurement and LTM CSI reporting configured for LTM measurements (operation 603, signal 605, signal 607). After the cell switch,when the UE 110 moves to DU2 (e.g., candidate cell 140), the UE 110 decodes the candidate cellconfiguration and, according to the CSI reporting configuration, combines or merges the CSI-RSsand respective configurations for LTM measurement and cell configuration to determineassociated RSs for measurement used for serving cell procedures (operation 609, signal 611).

[0095] Referring now to FIG. 7, shown is an example flowchart of a CSI-RS configurationsignaling process 700. The process 700, or blocks / steps / operations thereof, may be performed byone or more apparatuses 200a, 200b as shown in FIG. 2 and described herein. In variousembodiments, the apparatus performing the process 700 embodies a UE 110. In someembodiments, a network node associated with performance of the process 700 is embodied as oneor more apparatuses 200b.

[0096] In some embodiments, at block 703, the apparatus performing the process 700 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, forreceiving, from a network node, one or more CSI-RS configurations for a candidate cell. For example, the apparatus 200a may receive from a network node 120 one or more CSI-RS configurations for a candidate cell. In some embodiments, a respective CSI-RS configuration includes i) a first set of CSI-RS configurations for layer one (L1) measurement on the candidate cell, and ii) a second set of CSI-RS configurations for candidate cell configuration in association with a cell switch to the candidate cell. In some embodiments, a respective set of CSI-RSconfigurations comprises one or more CSI-RS resource configurations for a respective CSI-RS ofthe candidate cell. In some embodiments, a respective CSI-RS resource configuration indicates one or more NZP-CSI-RS resource sets for a respective CSI-RS of the candidate cell. In some embodiments, the network node embodies a gNodeB. In some embodiments, the candidate cell embodies an LTM candidate cell.

[0097] In some embodiments, at block 706, the apparatus performing the process 700 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for generating one or more L1 measurements for the one or more CSI-RS of the candidate cell based at least in part on the first set of CSI-RS configurations. For example, the apparatus 200a may generate one or more L1 measurements for the one or more CSI-RS of the candidatecell based at least in part on the first set of CSI-RS configurations. In some embodiments, at block709, the apparatus performing the process 700 optionally includes means, such as the processor 202a, the memory 204a, the network interface 206a, or the like, for provisioning to the networknode 120 a report comprising the one or more L1 measurements. For example, the apparatus 200amay provision to the network node 120 a report comprising the one or more L1 measurements.

[0098] In some embodiments, at block 712, the apparatus performing the process 700 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, forexecuting the cell switch to the candidate cell in response to a control message from the networknode 120. In some embodiments, the control message is based at least in part on a reportcomprising one or more L1 measurements for one or more CSI-RS of the candidate cell. In someembodiments, a respective L1 measurement is generated based at least in part on the first set ofCSI-RS configurations. In some embodiments, at block 715, the apparatus performing the process700 optionally includes means, such as the processor 202a, the memory 204a, the network interface206a, or the like, for decoding the second set of CSI-RS configurations in response to the executingof the cell switch to the candidate cell. For example, the apparatus 200a may decode the second set of CSI-RS configurations in association with the executing of the cell switch to the candidate cell.

[0099] In some embodiments, at block 718, the apparatus performing the process 700 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, fordetermining a subset of CSI-RSs of the candidate cell for BM and / or CSI reporting on the candidatecell based at least in part on the first set of CSI-RS configurations and the second set of CSI-RS configurations. For example, the apparatus 200a may determining a subset of CSI-RSs of thecandidate cell for BM and / or CSI reporting on the candidate cell based at least in part on the firstset of CSI-RS configurations and the second set of CSI-RS configurations. The determination mayembody a first approach as shown in FIGS. 3, 4, and 8 and described herein. Alternatively, thedetermination may embody a second approach as shown in FIG. 5, 6, and 9 and described herein.

[0100] In some embodiments, in association with the cell switch, the candidate cell embodies aserving cell for the apparatus performing the process 700. In some embodiments, at block 721, theapparatus performing the process 700 optionally includes means, such as the processor 202a, the memory 204a, the network interface 206a, or the like, for generating one or more BM L1measurements and / or CSI L1 measurement on the determined subset of CSI-RSs of the candidatecell. For example, the apparatus 200a may generate one or more BM L1 measurements and / or CSIL1 measurement on the determined subset of CSI-RSs of the candidate cell. In some embodiments,at block 724, the apparatus performing the process 700 optionally includes means, such as theprocessor 202a, the memory 204a, the network interface 206a, or the like, for provisioning to thecandidate cell a report comprising the one or more BM L1 measurements and / or CSI L1 measurement to cause the candidate cell to perform BM and / or CSI adaptation based at least in part on the at least one BM and / or CSI L1 measurement.

[0101] FIG. 8 shows an example flowchart of a CSI-RS configuration signaling process 800. Invarious embodiments, the process 800 embodies the CSI-RS configuration signaling provisioningapproach shown in FIGS. 3 and 4 and described herein. The process 800, or blocks / steps / operations thereof, may be performed by one or more apparatuses 200a, 200b as shown in FIG. 2 and described herein. In various embodiments, the apparatus performing the process 800 embodies a UE 110. In some embodiments, a network node associated with performance of the process 800 is embodied as one or more apparatuses 200b.

[0102] In some embodiments, at block 803, the apparatus performing the process 800 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for receiving from a network node 120 an instruction to apply one or more CSI-RS configurations for L1 measurement of respective RSs of a candidate cell to generation of one ormore BM and / or CSI L1 measurements of the candidate cell in association with a cell switch. Forexample, the apparatus 200a may receive from a network node 120 an instruction to apply one ormore CSI-RS configurations for L1 measurement of respective RSs of a candidate cell to generation of one or more BM and / or CSI L1 measurements of the candidate cell in association with a cell switch. In some embodiments the candidate cell embodies an LTM candidate cell. In some embodiments, the network node 120 embodies a gNodeB. In some embodiments, the apparatus performing the process 800 provisions to the network node 1120, a message indicative of capability to support multi-part CSI-RS configuration for BM and / or CSI reporting for acandidate cell. In some embodiments, the message includes a quantity of supportablecandidate cells for LTM. In some embodiments, the provisioning of the message to the networknode 120 causes the network node 120 to provision the message to one or more candidate cells tocause the respective candidate cells to generate one or more CSI-RS report configurations and arespective association between the CSI-RS report configuration and one or more CSI-RS resourceconfiguration based at least in part on the message.

[0103] In some embodiments, at block 806, the apparatus performing the process 800 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, forreceiving from a network node 120 one or more CSI-RS configurations for a candidate cell. For example, the apparatus 200a may receive from a network node 120 one or more CSI-RS configurations for a candidate cell. In some embodiments, a respective CSI-RS configuration includes one or more CSI-RS identifiers for respective RSs of the candidate cell and a respective CSI-RS configuration for L1 measurement of the respective RS of the candidate cell. In someembodiments, a respective CSI-RS configuration includes a first set of identifiers for one or moreCSI-RSs, CSI resource sets, or CSI resource configuration sets associated with L1 measurement and a second set of CSI-RS identifiers for one or more CSI-RSs, CSI resource sets, or resourceconfiguration sets associated with configuration of the candidate cell for BM and / or CSI reportingin association with a cell switch.

[0104] In some embodiments, at block 809, the apparatus performing the process 800 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for generating one or more L1 measurements for one or more CSI-RSs of the candidate cellbased at least in part on one or more CSI-RS configurations. For example, the apparatus 200a maygenerate one or more L1 measurements for one or more CSI-RSs of the candidate cell based at least in part on one or more CSI-RS configurations associated with the first set of identifiers. In some embodiments, a respective CSI-RS identifier of the second set of identifiers matches arespective CSI-RS of the first set of identifiers. In some embodiments, the second set of identifiersincludes a configuration resource set for the respective CSI-RS identifier, where the CSIconfiguration resource set is associated with configuration of the candidate cell and a cell switch.In some embodiments, the apparatus performing the process 800 applies the configuration resourceset of the second set to the generating of the one or more L1 measurements for the respective CSI-RS of the candidate cell.

[0105] Alternatively, in some embodiments, the first set of identifiers includes a configuration resource set for the respective CSI-RS identifier, where the CSI configuration resource set isassociated with L1 measurement of the respective RS of the candidate cell. In at least some of suchembodiments, the apparatus performing the process 800 may apply the configuration resource setof the first set of identifiers to the generating of the one or more L1 measurements for the respectiveCSI-RSs of the candidate cell. In some embodiments, a respective CSI-RS configuration includesan indication of whether to apply a CSI configuration resource set of the first set or a CSIconfiguration resource set of the second set to the generating of the one or more L1 measurementsfor the respective CSI-RS of the candidate cell.

[0106] In some embodiments, at block 812, the apparatus performing the process 800 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, forprovisioning to the network node a report including the one or more L1 measurements.

[0107] In some embodiments, at block 815, the apparatus performing the process 800 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, forexecuting a cell switch to the candidate cell in response to a control message from the networknode. For example, the apparatus 200a may execute a cell switch to the candidate cell in responseto a control message from the network node. In some embodiments, the control message is basedat least in part on the report comprising the one or more L1 measurements for the one or more CSI-RSs of the candidate cell. In some embodiments, the one or more L1 measurements is / are generated based at least in part on the at one or more CSI-RS configurations.

[0108] In some embodiments, at block 818, the apparatus performing the process 800 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for determining a subset of CSI-RSs of the candidate cell for BM and / or CSI reporting basedat least in part on the one or more CSI-RS identifiers and the respective CSI-RS configuration forL1 measurement of the respective RS of the candidate cell. For example, the apparatus 200a maydetermine a subset of CSI-RSs of the candidate cell for BM and / or CSI reporting based at least inpart on the one or more CSI-RS identifiers and the respective CSI-RS configuration for L1 measurement of the respective RS of the candidate cell.

[0109] In some embodiments, at block 821, the apparatus performing the process 800 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for, in association with the cell switch to the candidate cell, determining a set of indices of CSI-RSs of the candidate cell based at least in part on the one or more CSI-RS configurations,where the set of indices comprises an index for the respective CSI-RS of the respective RS of thecandidate cell. For example, the apparatus 200a may determine a set of indices of CSI-RSs of thecandidate cell based at least in part on the one or more CSI-RS configurations, where the set ofindices comprises an index for the respective CSI-RS of the respective RS of the candidate cell. Insome embodiments, the apparatus performing the process 800 receives from the network node 120a report configuration message, a resource configuration message, and / or the like. In someembodiments, the report configuration message or the resource configuration message includes anindication to refer to the one or more CSI-RS configurations for L1 measurement to determine theset of indices of CSI-RSs of the candidate cell for BM and / or CSI reporting for the candidate cell.

[0110] In some embodiments, at block 824, the apparatus performing the process 800 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for generating one or more BM L1 measurements, CSI L1 measurements, and / or the like ona subset of CSI-RSs of the candidate cell based at least in part on the set of indices of CSI-RSs ofthe candidate cell. For example, the apparatus 200a may generate one or more BM L1measurements, CSI L1 measurements, and / or the like on a subset of CSI-RSs of the candidate cellbased at least in part on the set of indices of CSI-RSs of the candidate cell. In some embodiments,at block 827, the apparatus performing the process 800 optionally includes means, such as theprocessor 202a, the memory 204a, the network interface 206a, or the like, for provisioning to thecandidate cell a report comprising the one or more BM L1 measurements, CSI L1 measurements,and / or the like to cause the candidate cell to perform BM or CSI adaptation based at least in parton the one or more BM L1 measurements, CSI L1 measurements, and / or the like.

[0111] FIG. 9 is an example flowchart of a CSI-RS configuration signaling process in accordancewith at least an example embodiment of the present disclosure. In various embodiments, theprocess 900 embodies the CSI-RS configuration signaling provisioning approach shown in FIGS.6 and 7 and described herein. The process 900, or blocks / steps / operations thereof, may be performed by one or more apparatuses 200a, 200b as shown in FIG. 2 and described herein. In various embodiments, the apparatus performing the process 900 embodies a UE 110. In someembodiments, a network node associated with performance of the process 900 is embodied as oneor more apparatuses 200b.

[0112] In some embodiments, at block 903, the apparatus performing the process 900 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for receiving a configuration indication including a bit field associated with one or more CSI-RS of a candidate cell. For example, the apparatus 200a may receive from the candidate cell (or other element of a network node 120) a configuration indication including a bit field associated with one or more CSI-RS of a candidate cell. In some embodiments, the bit field is configurablebetween a first value and a second value (e.g., 0 and 1). In some embodiments, in the second value,the bit field indicates that a respective CSI-RS configuration for L1 measurement of the one or more CSI-RS configurations for L1 measurement applies to BM and / or CSI reporting on thecandidate cell. In some embodiments, in the first value, the bit field indicates that a respective CSI-RS configuration for L1 measurement of the one or more CSI-RS configurations for L1 measurement does not apply to BM and / or CSI reporting on the candidate cell.

[0113] Additionally, or alternatively, in some embodiments, the apparatus performing the process900 optionally receives a configuration message including an instruction to, association withexecution of a cell switch, i) generate a combined set of configuration CSI-RSs based at least inpart on one or more CSI-RS identifiers of a first portion of a respective CSI-RS configuration andone or more one CSI-RS identifiers of a second portion of the respective CSI-RS configuration,and ii) use the combined set of configuration CSI-RSs in L1 measurement in BM and / or CSIreporting for the candidate cell. The apparatus performing the process 900 may receive theconfiguration message from the network node, one or more candidate cells, and / or the like.

[0114] In some embodiments, the apparatus performing the process 900 optionally provisions tothe network node, candidate cell, and / or the like, a configuration message indicative of capabilityto generate a combined set of configuration CSI-RSs based at least in part on a first portion (e.g.,L1 measurement portion) of one or more CSI-RS configurations. For example, the configurationmessage may indicate capability of the apparatus 200a to generate a combined set of configurationCSI-RSs based on one or more CSI-RS identifier of the candidate cell, where the one or more CSI-RS identifiers are provided in a first portion of a CSI-RS configuration. In some embodiments, theconfiguration message includes a quantity of supportable candidate cells for which a respective combined set of configuration CSI-RSs may be generated.

[0115] In some embodiments, at block 906, the apparatus performing the process 900 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for receiving an instruction from the network node 120 that indicates whether to prioritize CSI-RS configurations for L1 measurement or candidate cell configuration in instances in which a respective CSI-RS identifier of a first portion (e.g., L1 measurement portion) of a CSI-RS configuration matches a respective CSI-RS identifier of a second portion (e.g., cell configurationportion) of the CSI-RS configuration. For example, the apparatus 200a may receive the instructionfrom the network node 120. In some embodiments, based at least in part on the instruction, theapparatus performing the process 200a determines to prioritize i) the one or more CSI-RSconfigurations from the first portion, or ii) respective CSI-RS configurations from the secondportion in determining a subset of CSI-RSs of the candidate cell for BM and / or CSI reporting.

[0116] In some embodiments, at block 909, the apparatus performing the process 900 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, forreceiving from a network node 120 one or more CSI-RS configurations for a candidate cell. Forexample, the apparatus 200a may receive from a network node 120 one or more CSI-RSconfigurations for a candidate cell. In some embodiments, a respective CSI-RS configurationincludes a first portion and a second portion. In some embodiments, the first portion includes oneor more CSI-RS identifiers for respective RSs of the candidate cell and one or more CSI-RSconfigurations for L1 measurement of the respective RSs of the candidate cell. In someembodiments, the second portion includes one or more CSI-RS identifiers for respective RSs ofthe candidate cell and a respective CSI-RS configuration one or more RSs of the candidate cell forBM and / or CSI reporting (also referred to herein as CSI acquisition).

[0117] In some embodiments, at block 912, the apparatus performing the process 900 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for generating one or more L1 measurements for the respective CSI-RS of the candidate cellbased at least in part on the one or more CSI-RS configuration for L1 measurement of therespective RSs (e.g., first portion). For example, the apparatus 200a may generate one or more L1measurements for the respective CSI-RSs of the candidate cell based at least in part on the one ormore CSI-RS configuration for L1 measurement of the respective RSs. In some embodiments, at block 915, the apparatus performing the process 900 optionally includes means, such as theprocessor 202a, the memory 204a, the network interface 206a, or the like, for provisioning to thenetwork node 120 a report including the one or more L1 measurements. For example, the apparatus200a may provision to the network node 120 a report including the one or more L1 measurements.

[0118] In some embodiments, at block 918, the apparatus performing the process 900 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, forexecuting a cell switch to the candidate cell in response to a control message from the networknode 120. For example, the apparatus 200a may execute a cell switch to a candidate cell in responseto a control message from the network node 120. In some embodiments, the control message is based at least in part on the report comprising the one or more one L1 measurement for therespective CSI-RSs of the candidate cell. In some embodiments, the one or more L1 measurementsfor the respective CSI-RSs of the candidate cell is / are generated based at least in part on the one or more CSI-RS configurations for L1 measurement of the respective RSs.

[0119] In some embodiments, at block 921, the apparatus performing the process 900 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, forgenerating a combined set of configuration CSI-RSs based at least in part on the one or more CSI-RS identifier of the first portion of the one or more CSI-RS configurations of operation 909 and the one or more CSI-RS identifiers of the second portion of said CSI-RS configurations. Forexample, the apparatus 200a may generate a combined set of configuration CSI-RSs based at leastin part on the one or more CSI-RS identifiers of the first portion and the one or more CSI-RS identifiers of the second portion. In some embodiments, a respective CSI-RS identifier of the second portion embodies a reference to a respective CSI-RS identifier of the first portion. Based at least in part on the reference embodied by the respective CSI-RS identifier, the apparatus performing the process 900 may determine from the first portion a respective CSI-RSconfiguration of the one or more CSI-RS configurations for L1 measurement to enable use of therespective CSI-RS configuration for BM and / or CSI reporting.

[0120] In some embodiments, at block 924, the apparatus performing the process 900 includesmeans, such as the processor 202a, the memory 204a, the network interface 206a, or the like, fordetermining a subset of CSI-RSs of the candidate cell for BM and / or CSI reporting based at leastin part on the combined set of CSI-RSs; and the respective CSI-RS configurations for BM and / orCSI reporting of the second portion. For example, the apparatus 200a may determine a subset ofCSI-RSs of the candidate cell for BM and / or CSI reporting based at least in part on the combinedset of CSI-RSs; and the respective CSI-RS configurations for BM and / or CSI reporting.

[0121] In some embodiments, the apparatus performing the process 900 determines the subset ofCSI-RSs for BM and / or CSI reporting based at least in part on one or more instructions, preconfigured standards, and / or the like. For example, a respective CSI-RS identifier of the first portion may match a respective CSI-RS identifier of the second portion. In such instances, the apparatus 200a may prioritize the respective CSI-RS configuration from the second portion over the identifier-associated CSI-RS configuration from the first portion in determining the subset ofCSI-RSs of the candidate cell for BM and / or CSI reporting. Alternatively, the apparatus 200a mayprioritize the identifier-associated CSI-RS configuration from the first portion in place of therespective CSI-RS configuration from the second portion in determining the subset of CSI-RSs ofthe candidate cell for BM and / or CSI reporting. As described herein with reference to operation 906, the apparatus performing the process 900 may receive instructions for prioritization from a network node 120, candidate cell, and / or the like.

[0122] Additionally, or alternatively, the apparatus performing the process 900 may determine thesubset of CSI-RSs of the candidate cell for BM and / or CSI reporting based at least in part on therespective CSI-RS configuration for L1 measurement. As described herein with reference to operation 903, the apparatus performing the process 900 may receive a configuration indication(e.g., bit field configurable between a first value and a second value) for indicating whether arespective CSI-RS configuration for L1 measurement applies to BM and / or CSI reporting on the candidate cell.

[0123] In some embodiments, at block 927, the apparatus performing the process 900 optionallyincludes means, such as the processor 202a, the memory 204a, the network interface 206a, or thelike, for generating one or more BM measurements, CSI L1 measurements, and / or the like on thedetermined subset of CSI-RSs of the candidate cell. For example, the apparatus 200a may generateone or more BM measurements, CSI L1 measurements, and / or the like on the determined subset of CSI-RSs of the candidate cell. In some embodiments, at block 930, the apparatus performing the process 900 optionally includes means, such as the processor 202a, the memory 204a, thenetwork interface 206a, or the like, for provisioning to the candidate cell a report including the oneor more BM measurements, CSI L1 measurements, and / or the like. For example, the apparatus 200a may provision report including the one or more BM measurements, CSI L1 measurements, and / or the like to the candidate cell to cause the candidate cell to perform BM or CSI adaptationbased at least in part on the one or more BM L1 measurements, CSI L1 measurements, and / or thelike.

[0124] In various embodiments, the method, apparatus and computer program product of the present disclosure are provided for provisioning CSI-RS configurations for L1 measurement and candidate cell configuration to a UE. The method, apparatus, and computer program product provide improved solutions for provisioning CSI-RS configurations with reduced overhead. Invarious embodiments, the method, apparatus, and computer program product a multi-portionframework for provisioning CSI-RS configuration of for a candidate cell such that, when the CSI-RS configuration for a candidate cell is divided into two parts as described herein above, the report-configuration for beam management after cell-switch may refer to the resource-configurationsmaintained outside the candidate configuration (e.g., within L1 measurement configuration). In various embodiments, the method, apparatus, and computer program product improve telecommunication services by overcoming technical challenges associated with implementingCSI-RS-based LTM, including excess overhead in provisioning CSI-RS configurations to UEs forL1 measurement and cell configuration.

[0125] It will be understood that each block of the flowcharts and combination of blocks in theflowcharts show in the figures and described herein may be implemented by various means, suchas hardware, firmware, processor, circuitry, and / or communication devices associated with execution of software including one or more program instructions. For example, one or more ofthe procedures or operations described above may be embodied by computer program instructions.In this regard, the computer program instructions which embody the procedures or operationsdescribed above may be stored by a memory 204a or memory 204b of an apparatus (e.g., a UE ornetwork node employing a disclosed embodiment and executed by a processor 202a or processor202b). As will be appreciated, any such computer program instructions may be loaded onto a computer or other programmable apparatus (for example, hardware) to produce a machine, such that the resulting computer or other programmable apparatus implements the functions specified in the flowchart blocks. These computer program instructions may also be stored in a computer- readable memory that may direct a computer or other programmable apparatus to function in aparticular manner, such that the instructions stored in the computer-readable memory produce anarticle of manufacture the execution of which implements the function specified the flowchart blocks. The computer program instructions may also be loaded onto a computer or otherprogrammable apparatus to cause a series of operations to be performed on the computer or otherprogrammable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide operations for implementing the functions specified in the flowchart blocks.

[0126] Many modifications and other embodiments of the present disclosure set forth herein willcome to mind to one skilled in the art to which these embodiments pertain having the benefit ofthe teachings presented in the foregoing descriptions and the associated drawings. Therefore, it isto be understood that the disclosure is not to be limited to the specific embodiments disclosed andthat modifications and other embodiments are intended to be included within the scope of theappended claims. Moreover, although the foregoing descriptions and the associated drawingsdescribe example embodiments in the context of certain example combinations of elements and / orfunctions, it should be appreciated that different combinations of elements and / or functions can beprovided by alternative embodiments without departing from the scope of the appended claims. Inthis regard, for example, different combinations of elements and / or functions than those explicitlydescribed above are also contemplated as can be set forth in some of the appended claims.Although specific terms are employed herein, they are used in a generic and descriptive sense onlyand not for purposes of limitation.

Claims

CLAIMSThat which is claimed is:

1. An apparatus, comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least oneprocessor, cause the apparatus at least to: receive, from a network node, at least one channel state information reference signal (CSI-RS) configuration for a candidate cell, the at least one CSI-RS configurationcomprising:a first set of CSI-RS configurations for layer one (L1) measurement on thecandidate cell; and asecond set of CSI-RS configurations for candidate cell configuration inassociation with a cell switch to the candidate cell; execute the cell switch to the candidate cell in response to a control message fromthe network node, wherein: the control message is based at least in part on a report comprising at leastone L1 measurement for at least one CSI-RS of the candidate cell; and the at least one L1 measurement is generated based at least in part on thefirst set of CSI-RS configurations; anddetermine a subset of CSI-RSs of the candidate cell for at least one of beammanagement (BM) or CSI reporting based at least in part on the first set of CSI-RSconfigurations and the second set of CSI-RS configurations.

2. The apparatus of claim 1, wherein the instructions, when executed by the at least oneprocessor, further cause the apparatus to: generate the at least one L1 measurement for the at least one CSI-RS of the candidate cellbased at least in part on the first set of CSI-RS configurations; and provision to the network node the report comprising the at least one L1 measurement.

3. The apparatus of claim 1, wherein:in association with the cell switch, the candidate cell embodies a serving cell; andthe instructions, when executed by the at least one processor, further cause the apparatusto: generate at least one of at least one BM measurement or at least one CSI L1measurement on the determined subset of CSI-RSs of the candidate cell; and provision to the candidate cell a report comprising at least one of the at least oneBM measurement or the at least one CSI L1 measurement to cause the candidate cell to perform at least one of BM or CSI adaptation based at least in part on the report.

4. The apparatus of claims 1 or 2, wherein the instructions, when executed by the at leastone processor, further cause the apparatus to: decode the second set of CSI-RS configurations in response to the executing of the cellswitch to the candidate cell.

5. The apparatus of any of claims 1-3, wherein:a respective set of CSI-RS configurations comprises at least one CSI-RS resourceconfiguration for a respective CSI-RS of the candidate cell.

6. The apparatus of claim 5, wherein:the at least one CSI-RS resource configuration indicates at least one non-zero power(NZP) CSI-RS resource set for a respective CSI-RS of the candidate cell.

7. The apparatus of any of claims 1-6, wherein:the candidate cell embodies a lower layer-triggered mobility (LTM) candidate cell.

8. The apparatus of any of claims 1-7, wherein:the network node embodies a gNodeB.

9. The apparatus of any of claims 1-8, wherein:the apparatus embodies a user equipment (UE).

10. A method according to of any of claims 1-9.

11. An apparatus comprising means for performing the method of claim 10.

12. A computer program product comprising at least one non-transitory computer-readablestorage medium having computer-executable program code instructions stored therein, the computer-executable program code instructions comprising program code instructions configured to perform the method of claim 10.

13. An apparatus, comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least oneprocessor, cause the apparatus at least to: provision, to a UE, at least one channel state information reference signal (CSI-RS) configuration for a candidate cell, the at least one CSI-RS configuration comprising:a first set of CSI-RS configurations for layer one (L1) measurement on thecandidate cell; anda second set of CSI-RS configurations for candidate cell configuration inassociation with a cell switch to the candidate cell; receive from the UE a report comprising at least one L1 measurement for at leastone CSI-RS of the candidate cell, wherein the at least one L1 measurement is generated based at least in part on the first set of CSI-RS configurations; based on the report, provision to the UE a control message to cause the UE toexecute the cell switch, and, in association with the cell switch, determine a subset ofCSI-RSs of the candidate cell for at least one of beam management (BM) or CSIreporting based at least in part on the first set of CSI-RS configurations and the secondset of CSI-RS configurations.

14. The apparatus of claim 13, wherein:a respective set of CSI-RS configurations comprises at least one CSI-RS resourceconfiguration for a respective CSI-RS of the candidate cell.

15. The apparatus of claim 14, wherein:the at least one CSI-RS resource configuration indicates at least one non-zero power(NZP) CSI-RS resource set for a respective CSI-RS of the candidate cell.

16. The apparatus of any of claims 13-15, wherein:the candidate cell embodies a lower layer-triggered mobility (LTM) candidate cell.

17. The apparatus of any of claims 13-16, wherein:the apparatus embodies a gNodeB.

18. A method according to of any of claims 13-17.

19. An apparatus comprising means for performing the method of claim 18.

20. A computer program product comprising at least one non-transitory computer-readablestorage medium having computer-executable program code instructions stored therein, the computer-executable program code instructions comprising program code instructions configured to perform the method of claim 18.

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