Reference signal measurement for performance monitoring

Abstract

Example embodiments of the present disclosure relate to methods, devices, apparatuses and computer readable storage medium of reference signal measurement for performance monitoring. In a method, a first apparatus, receives, from a second apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals. The set of reference signals is applied across a plurality of time durations. The first apparatus further receives, from the second apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations. The first apparatus performs, based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations.

Description

REFERENCE SIGNAL MEASUREMENT FOR PERFORMANCE MONITORINGCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority from, and the benefit of, Finland application No 20245403, filed April 4, 2024, the contents of which are hereby incorporated by reference in their entirety.FIELDS

[0002] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium of reference signal (RS) measurement for performance monitoring.BACKGROUND

[0003] In some communication systems such as the next cellular systems, artificial intelligence (Al) and / or machine learning (ML) technology is proposed to be used to improve the communication performance. An AI / ML model may be applied in the new radio (NR) radio interface to assist model functionalities or communication-related functions, such as, channel state information (CSI) overhead reduction, beam management (BM), positioning, and the like. For example, the AI / ML- based beam management targets spatial and / or time beam prediction for overhead and latency reduction. The AI / ML based functions such as air-interface functions need to be enhanced.SUMMARY

[0004] In a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from a second apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; receive, from the second apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations; and perform, based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations.

[0005] In a second aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions ithat, when executed by the at least one processor, cause the second apparatus at least to: transmit, to a first apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; and transmit, to the first apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations.

[0006] In a third aspect of the present disclosure, there is provided a method. The method comprises: receiving, at a first apparatus from a second apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; receiving, from the second apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations; and performing, based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations.

[0007] In a fourth aspect of the present disclosure, there is provided a method. The method comprises: transmitting, at a second apparatus to a first apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; and transmitting, to the first apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations.

[0008] In a fifth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for receiving, from a second apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; means for receiving, from the second apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations; and means for performing, based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations.

[0009] In a sixth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for transmitting, to a first apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; and means for transmitting, to the first apparatus, a second indication that at least one rule is applied todetermine a subset of the set of reference signals for each time duration of the plurality of time durations.

[0010] In a seventh aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform the method according to the third or fourth aspect.

[0011] It is to be understood that the Summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0013] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0014] FIG. 2 illustrates a signaling diagram for reference signal measurement for performance monitoring according to some example embodiments of the present disclosure;

[0015] FIG. 3 illustrates another signaling diagram for reference signal measurement for performance monitoring according to some example embodiments of the present disclosure;

[0016] FIG. 4 illustrates another signaling diagram for reference signal measurement for performance monitoring according to some example embodiments of the present disclosure;

[0017] FIG. 5 illustrates a flowchart of a method implemented at a first apparatus according to some example embodiments of the present disclosure;

[0018] FIG. 6 illustrates a flowchart of a method implemented at a second apparatus according to some example embodiments of the present disclosure;

[0019] FIG. 7 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0020] FIG. 8 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0021] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0022] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0023] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0024] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0025] It shall be understood that although the terms “first,” “second” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0026] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0027] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0029] As used in this application, the term “circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable):(i) a combination of analog and / or digital hardware circuit(s) with software / firmware and(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and(c) hardware ci rcuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0030] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0031] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE- Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-loT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1 G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Giventhe rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0032] As used herein, the term “network device” or “network access device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0033] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehiclemounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0034] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0035] As used herein, the term “model” is referred to as an association between an input and an output learned from training data, and thus a corresponding output may be generated for a given input after the training. The generation of the model may be based on a ML technique. The ML techniques may also be referred to as Al techniques. In general, a ML model can be built, which receives input information and makes predictions based on the input information. As used herein, a model is equivalent to an AI / ML model, or a data-driven / data processing algorithm / procedure.

[0036] As described above, an AI / ML model may be applied in the NR radio interface to assist model functionalities or communication-related functions. In an example use case, the AI / ML model may be used for channel state information (CSI) feedback enhancement, such as overhead reduction, improved accuracy and prediction. In another example use case, the AI / ML model may be used for beam management, such as beam prediction in time and / or spatial domain for overhead and latency reduction, and / or beam selection accuracy improvement. In a further example use case, the AI / ML model may be used for positioning accuracy enhancements for different scenarios including those with heavy non-line of sight (NLOS) conditions. The AI / ML approaches may be diverged to support various requirements on the gNB-UE levels.

[0037] The AI / ML model may be in UE-side or network (NW)-side. For UE-sided model, the UE may perform prediction and report the predicted Set A beam identifier (ID), or reference signal received power (RSRP) or Top-K of Set A beam ID(s) / RSRP in future time steps to the network. For NW-sided model, the NW predict Set A beam IDs / RSRP or Top-K of Set A beam ID(s) / RSRP in future time steps using history of Set B beam measurement reported by UE.

[0038] In some cases, the AI / ML based beam management may be spatial and / or time domain beam prediction. The spatial beam prediction (also referred to as BM-Case1) is to predict one or more best Tx beams or Tx-Rx beam pairs or corresponding reference signal received power (RSRP) values in different spatial locations. The time-domain beam predictions (also referred to as BM- Case2) aim to predict the best Tx beams or Tx-Rx beam pairs to use for next time instants, e.g.,beam prediction in the spatial domain (BM-Case1) for next time instants.

[0039] Several mechanisms have been proposed for AI / ML functionality identification and functionality-based lifecycle management (LCM) of UE-side models and / or UE-part of two-sided models. In some mechanisms, AI / ML general framework for one-sided AI / ML models within the realm of what has been studied for AI / ML in NR. The signaling and protocol aspects of LCM enable functionality and model selection, activation, deactivation, switching, fallback, or the like. Identification related signaling is part of the LCM. Necessary signaling or mechanisms for LCM may be used to facilitate model training, inference, performance monitoring, data collection (except for the purpose of core network (CN), operation, administration, and maintenance (0AM) or over- the-top (OTT) collection of UE-sided model training data) for both UE-sided and NW-sided models.

[0040] In some mechanisms for beam management, downlink (DL) transmitting (Tx) beam prediction for both UE-sided model and NW-sided model, encompassing the following: spatial- domain DL Tx beam prediction for Set A of beams based on measurement results of Set B of beams (“BM-Case1”), and / or temporal DL Tx beam prediction for Set A of beams based on the historic measurement results of Set B of beams (“BM-Case2”). Necessary signalling / mechanism(s) may be specified to facilitate LCM operations specific to the Beam Management use cases, if any. Method(s) may be enabled to ensure consistency between training and inference regarding NW- side additional conditions (if identified) for inference at UE

[0041] Necessity and details of model Identification concept and procedure in the context of LCM are specified. For CN / OAM / OTT collection of UE-sided model training data, for some use cased, the corresponding contents of UE data collection are identified. The UE data collection mechanisms are analyzed along with the implications and limitations of each of the methods. For model transfer / delivery, whether there is a need to consider standardized solutions for transferring / delivering AI / ML model(s) considering at least the solutions may be determined. In some cases, offline training is assumed. It will not hide model design information from other vendors when shared.

[0042] In some mechanisms, benchmark or reference for the performance comparison, including at least one of: best beam(s) obtained by measuring beams of a set indicated by gNB (e.g., Beams from Set A), or measurements of the predicted best beam(s) corresponding to model output (e.g., Comparison between actual L1-RSRP and predicted RSRP of predicted Top-1 / K Beams). Signalling, configuration, measurement and / or report for model monitoring, e.g., signalling aspects related to assistance information (if supported), reference signals, or the like are specified.

[0043] In some mechanisms, for BM-Case1 and BM-Case2 with a UE-side AI / ML model, a Type1 performance monitoring may be performed. For the Type 1 performance monitoring, configurations or signaling from gNB to UE for measurement and / or reporting are specified. UE may have different operations. In a first option, such as a NW-side performance monitoring option, UE sends reporting to NW (e.g., for the calculation of performance metric at NW). In a second option, such as a UE-assisted performance monitoring, UE calculates performance metric(s), either reports it to NW or reports an event to NW based on the performance metric(s). Indication may be transmitted from NW for UE to do LCM operations. It is to be noted that at least the performance and reporting overhead of model monitoring mechanism may be considered for the Type 1 performance monitoring.

[0044] A Type 2 performance monitoring is also proposed, for which an indication, request, or report from UE to gNB for performance monitoring is specified. The indication or request or report may be not needed in some cases. In addition, configuration or signalling from gNB to UE for performance monitoring measurement and / or reporting may be specified. If it is for UE side model monitoring, UE makes decision(s) of model selection / activation / deactivation / switching / fallback operation. In such cases, mechanism that facilitates the UE to detect whether the functionality / model is suitable or no longer suitable.

[0045] For BM-Case1 and BM-Case2 with a NW-side AI / ML model, beam measurement and report for model monitoring has been proposed. The indication, request, or report from UE to gNB for performance monitoring is specified. The indication / request / report may be not needed in some case(s). In addition, configurations or signaling from gNB to UE for performance monitoring measurement and / or reporting is specified. If it is for UE side model monitoring, UE makes decision(s) of model selection / activation / deactivation / switching / fallback operation. In such cases, mechanism that facilitates the UE to detect whether the functionality / model is suitable or no longer suitable.

[0046] In some mechanisms for AI / ML BM, the beam measurements are used as input to neural network, and they are called as Set B beams where the output of the neural network is called as Set A beams. However, in the AI / ML based beam prediction such as release (Rel)-19 AI / ML based beam prediction (performed at the UE), using current CSI measurement and reporting framework, the Set A needs to be reported if NW performs performance monitoring.

[0047] In some cases, when the UE performs prediction, the NW may make decision whether to configure UE to switch to other functionality / model or configure UE to switch back to legacy CSI reporting. One option may be the NW to monitor the prediction output (e.g., based on performance metric) reported by UE from time to time and being able to make decision whether to rely on prediction based reporting or legacy beam reporting.

[0048] In some cases, if the UE is able to perform prediction and also performs performance monitoring, the UE may report the monitoring output to the NW. In this case, the NW may make decision whether to configure UE to switch to other functionality / model or configure UE to switch back to legacy, based on monitoring output reported by the UE.

[0049] In addition, for NW-sided model, the NW will need measurements reporting from UE in order to compare the performance of prediction for performance monitoring.

[0050] To enable the performance monitoring framework for BM-Case2, the NW will need to trigger UE to report measurement results (for NW-sided performance monitoring for a UE / NW-sided model) or monitoring metrics (for UE-assisted performance monitoring for a UE-sided model) for a set of monitoring RS resources, e.g., full Set A or subset of Set A beams (in one time instant or multiple time instances). For this process, the following details are not clear: for BM-Case-2, it is not clear what is the monitoring RS resources for performance monitoring and whether the monitoring RS resources are same for all time instances / periods where prediction is performed by the UE, this is especially applicable issue when the NW configures UE to report a subset of RS resources from Set A in multiple time sequences; and for BM-Case2, it is not clear how to define the sub-set of RS resources from Set A to the UE or how the UE may assume that sub-set of RS resource from Set A as monitoring RS resources.

[0051] In order to solve at least part of the above problems or other potential problems, a solution on reference signal measurement for performance monitoring is proposed. According to example embodiments, a second apparatus (for example, a network device) transmits, to a first apparatus (for example, a terminal device), a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals. The set of reference signals is applied across a plurality of time durations. The second apparatus further transmits a second indication to the first apparatus. The second indication indicates that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations. Based on the first and second indications, the first apparatus performs at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations .

[0052] In this manner, the first apparatus can determine the subset of reference signals for which the measurement is performed. The resource utilization can thus be improved. In addition, the power consumption can be reduced.

[0053] Principle and implementations of the present disclosure will be described in detail below with reference to FIGS. 1-8. FIG. 1 illustrates an example communication environment 100 in which example embodiments of the present disclosure can be implemented. In the communicationenvironment 100, a plurality of communication apparatuses, including a first apparatus 110 and a second apparatus 120, can communicate with each other.

[0054] In some example embodiments, if the first apparatus 110 is a terminal device and the second apparatus 120 is a network device serving the terminal device, a link from the second apparatus 120 to the first apparatus 110 is referred to as a downlink (DL), while a link from the first apparatus 110 to the second apparatus 120 is referred to as an uplink (UL). In DL, the second apparatus 120 is a transmitting (TX) device (or a transmitter) and the first apparatus 110 is a receiving (RX) device (or a receiver). In UL, the first apparatus 110 is a TX device (or a transmitter) and the second apparatus 120 is a RX device (or a receiver).

[0055] In some example embodiments, multiple input multiple output (MIMO) is supported in the communication environment 100. For example, the second apparatus 120 and the first apparatus 110 may communicate with each other via different beams to enable a directional communication. The first apparatus 110 may be configured with at least one beam (corresponding to at least one reference signal (RS)) used as reference for receiving / transmitting data and control channels. For example, the first apparatus 110 may have one or more physical downlink control channel (PDCCH) channels and one or more physical downlink shared channel (PDSCH) channels. The one or more PSCCH channels and / or one or more PDSCH channels may be configured to be received on one or more DL beams. UE may be capable of beamforming (i.e., it may be capable of forming UL / DL beams for TX and RX) or it may use omnidirectional transmission and reception.

[0056] As illustrated in FIG. 1 , the second apparatus 120 transmits downlink transmission to the first apparatus 110 via one or more of beams 140-1 , 140-2, . , and 140-K (K being an integer greater than or equal to 1 ). For purpose of discussion, the beams 140-1 , 140-2, . , and 140-K are collectively or individually referred to as beam 140.

[0057] Correspondingly, in uplink, the second apparatus 120 is an RX device (or a receiver) and the first apparatus 110 is a TX device (or a transmitter), and the first apparatus 110 may transmit uplink transmission to the second apparatus 120 via one or more beams. As illustrated in FIG. 1 , the first apparatus 110 transmits uplink transmission to the second apparatus 120 via the beams 130-1 , 130-2, . , and 130-J (J being an integer greater than or equal to 1). For purpose of discussion, the beams 130-1 , 130-2, . , and 130-J are collectively or individually referred to as beam 130.

[0058] In the example of FIG. 1, the second apparatus 120 has a certain coverage range, which may be called as a serving area or a cell (not shown). The first apparatuses 110 are located in the cell covered by the second apparatus 120. In the communication environment 100, the second apparatus 120 may communicate data and control information to the first apparatus 110 and thefirst apparatus 110 may also communication data and control information to the second apparatus 120.

[0059] The coverage area or the cell may be covered by one or more beams provided by one or more Transmission / Reception Points (TRPs), for example, TRP#1, ... TRP#X. Each beam may carry an identifier enabling the first apparatus 110 to identify a beam and perform measurements (e.g., received power, RSRP) and other relevant measurements associate with specific identifier. Each synchronization signal block (SSB) may be identified based on the identifier carried by SSB block. Furthermore, for downlink measurement signals for beam management SSB beam may be further used to train.

[0060] In some example embodiments, a model functionality such as an AI / ML based functionality may be provided for the first apparatus 110. For example, an AI / ML based beam management, CSI compression or any other suitable functionality may be provided. In the following description, some example embodiments will be described with the functionality being an AI / ML based beam prediction. It is to be understood that some example embodiments described with respect to the AI / ML based beam prediction may also be applied to other suitable AI / ML based functionality. Scope of embodiments of the present disclosure is not limited here.

[0061] In an example embodiment, the second apparatus 120 may provide a plurality of beams for the first apparatuses 110. The model functionality may be an AI / ML based beam management which predicts a beam such as a DL Tx beam for the first apparatus 110. In another example, the model functionality may be an AI / ML based beam management which predicts a DL Tx Rx beam pair for the first apparatus 110. For purpose of illustration, some example embodiments hereinafter will be described with the beam management or beam prediction as the model functionality.

[0062] The AI / ML based beam management may be spatial and / or time domain beam prediction. The spatial beam prediction (also referred to as BM-Case1 ) is to predict one or more best Tx beams or Tx-Rx beam pairs or corresponding reference signal received power (RSRP) values in different spatial locations. The time-domain beam predictions (also referred to as BM-Case2) aim to predict the best Tx beams or Tx-Rx beam pairs to use for next time instants, e.g., beam prediction in the spatial domain (BM-Case1) for next time instants. For purpose of illustration, some example embodiments are described where the model functionality is the spatial and / or time domain beam prediction.

[0063] In some example embodiments, one or more models may derive an outcome such as the predicted beam of the beam management. The one or more models may be implemented at the first apparatus 110 (shown as a model 115), or the second apparatus 120 (not shown), or both (not shown). The first apparatus 110 and / or the second apparatus 120 may perform the beammanagement by running inference or perform training. For purpose of illustration, some example embodiments hereinafter will be described with the model 115 implemented at the first apparatus 110. The model 115 may be an AI / ML model such as a neural network. Examples of the model include but not limited to a long short-term memory (LSTM), a convolutional LSTM (conv-LSTM), or a transformer.

[0064] In the example of FIG. 1 , by using the model 115, the first apparatus 110 may use beam measurement results of M historical time instances to predict future beam(s) of N future time instances, where M is larger than one and N is larger than or equal to one. The beam measurement results of M historical time instances refer to measurement results of M latest measurement instances (represented as, Pi, P2, ..., PM in the following text), which are used as input of the model 115. The output of the model is N predictions for N future time instances (represented as, F1, F2, ..., FN in the following text), where each prediction corresponds to one future time instance and may comprise one or more predicted beams.

[0065] In some example embodiments, the performance or functionality of the model 115 needs to be monitored. Details regarding the monitoring of the model 115 will be described with respect to FIG. 2.

[0066] It is to be understood that the number of apparatuses and their connections shown in FIG. 1 are only for the purpose of illustration without suggesting any limitation. The communication environment 100 may include any suitable number of apparatuses configured to implementing example embodiments of the present disclosure.

[0067] In the following, for purpose of illustration, some example embodiments are described with the first apparatus 110 operating as a terminal device and the second apparatus 120 operating as a network device. However, in some example embodiments, operations described in connection with a terminal device may be implemented at a network device or other device, and operations described in connection with a network device may be implemented at a terminal device or other device.

[0068] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1 G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division MultipleAccess (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0069] FIG. 2 illustrates a signaling diagram 200 for reference signal measurement for performance monitoring according to some example embodiments of the present disclosure. The signaling diagram 200 involves the first apparatus 110 and the second apparatus 120 in FIG. 1. For purpose of illustration, the signaling diagram 200 will be described with respect to FIG. 1 . For purpose of discussion, some example embodiments are described where the first apparatus 110 is implemented as a terminal device and the second apparatus 120 is implemented as a network device.

[0070] As shown in FIG. 2, the second apparatus 120 transmits (210), to the first apparatus 110, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals. The set of reference signals is applied across a plurality of time durations. The first apparatus 110 receives (220) the first indication. By way of example, the first indication may be a trigger command, a medium access control control element (MAC CE) indication, or a radio resource control (RRC) configuration, or the like. That is, the first indication may be transmitted (205) via any suitable signaling such as DCI, RRC or MAC CE.

[0071] As used herein, the term “time duration” may be referred to as a “time window”, a “prediction time window” or a “prediction time duration”. The term “time duration” may also correspond to a “time instance” or a “prediction time instance”. For example, a model at the first apparatus 110 or at the second apparatus 120 may predict beam(s) at a plurality of time instances such as future time instances. A duration between two consecutive time instances may be referred to as a time duration. The term “prediction time duration (or window)” or “time duration (or window)” may refer to a time window for outputting a sequence of outcomes of prediction such as beam prediction from a model or by the model implemented at the first apparatus 110 and / or the second apparatus 120. During the time duration(s), the performance monitoring for the model may be performed. The time duration may be periodic or aperiodic. As used herein, the set of RSs applied across the plurality of time durations means that the set of RSs is applied at the plurality of time instances.

[0072] In some example embodiments, the set of reference signals may be the set that defines the predicted RSs across a plurality of prediction time durations such as all prediction time windows. The set of reference signals may be referred to as “Set A”. A same Set A may be applied across [TI , T2, ..., TN] future time durations, N being a positive integer. The subset of the set of referencesignals may be referred to as “subset of Set A”.

[0073] In some example embodiments, the performance monitoring may be performed at the first apparatus 110 or the second apparatus 120. The monitoring may be performed for a model at the first apparatus 110 and / or the second apparatus 120. In some example embodiments, the RS resources such as non-zero power channel state information reference signals (NZP CSI-RSs) resources or SSB resources may be configured by the second apparatus 120. The model at the first apparatus 110 and / or the second apparatus 120 may perform the beam prediction based on the configured RS resources or SSB resources.

[0074] For performance monitoring for the model at the second apparatus 120 (such as a NW- sided model) or the model at the first apparatus 110 (such as a UE-sided model) in BM-Case2, the first apparatus 110 may receive (220) the first indication from the second apparatus 120 to determine a subset of reference signals associated with the performance monitoring. The subset of RSs may be referred to as a subset of Set A.

[0075] The second apparatus 120 transmits (230), to the first apparatus 110, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations. The first apparatus 110 receives (240) the second indication. By way of example, the second indication may be a trigger command, a medium access control control element (MAC CE) indication, or a radio resource control (RRC) configuration, or the like. That is, the second indication may be transmitted (205) via any suitable signaling such as DCI, RRC or MAC CE. For example, for performance monitoring for a NW-sided model or a UE-sided model in BM-Case2, the first apparatus 110 receives (240) the second indication from the second apparatus 120 to use a rule to determine the subset of Set A as monitoring RS resources.

[0076] In some example embodiments, the second apparatus 120 may transmit, to the first apparatus 110, a third indication whether a different subset of the set of reference signals are applicable for each time duration of the plurality of time durations. The first apparatus 110 may receive the third indication. The third indication may indicate whether the same or different subsets are applicable for reporting in the future time durations. Then third indication may be transmitted via any suitable signaling such as DCI, RRC or MAC CE. For the case of the first indication from the second apparatus 120 to determine that a measurement report is associated with a subset of Set A, the first apparatus 110 may receive the indication to determine the subset of Set A. The first apparatus 110 may further receive the indication wherein the same or different subsets are applicable for future time instances reporting.

[0077] Alternatively, in some example embodiments, the first indication may also act as the thirdindicator. That is, the second apparatus 120 may not transmit a separate third indication. The first indication may additionally indicate whether a different subset of the set of reference signals is applicable for each time duration of the plurality of time durations. In other words, the subset of Set A RSs may be defined differently for each prediction time instance / out of N time instances. For example, subset 1 is used for a first future time instance, subset 2 is used for a second future time instance, and so on.

[0078] By applying different subsets of Set A for each time window 7), the activated TCI state may be different for different time instance / , which leads to different ARS resources associated to subset of Set A.

[0079] In some example embodiments, a plurality of sets of reference signal indices received for a plurality of subsets of the set of reference signals indicates that a different subset from the plurality of subsets of the set of reference signals are applicable in each time duration of the plurality of time durations. The plurality of sets of reference signal indices may be received in a medium access control (MAC) message.

[0080] In some example embodiments, the signaling of the second indication may further consider the indication of different subsets for different future time durations. In an example embodiment, RS indices for subset 1 and RS indices for subset 2 (assuming two time instances in future) may be indicated by a MAC-CE message where the first apparatus 110 knows different subset of Set A for each future time instance. The first apparatus 110 may consider those subsets of Set A as monitoring RS resources for each future time duration. By way of example, for i < N future time instances: the RS#1 for subset 1 of SetA (to be applied totime instance), RS#2 for subset 2 of SetA (to be applied to T2time instance),... , RS#3 for subset N of SetA may be indicated by a MAC-CE message where the first apparatus 110 knows different subsets of Set A for i future time instance. The first apparatus 110 may consider those as monitoring RS resources for i future time instance.

[0081] As mentioned, the second indication indicates that at least one rule is applied to determine the subset of set of RSs. In some example embodiments, the at least one rule includes a rule that a set of quasi co-located (QCL) source reference signals, e.g., QCL Type-D, are determined for a respective subset of the set of reference signals applied to each time duration of the plurality of time durations, based on association between the time duration and a set of transmission configuration indicator (TCI) states corresponding to the set of quasi co-located source reference signals.

[0082] In an example embodiment, the set of TCI states may be activated by the second apparatus 120 for the first apparatus 110. That is, the rule may be defined to select a QCL sourceRS included in the activated TCI state(s) when determining the subset of Set A. A different set of TCI states may be associated with each time duration of a number of consecutive time durations among the plurality of time durations. For example, different time windows may have different active TCI states which then further corresponding to different QCL source RSs. Table 1 shows an example of defining subset of Set A for performance monitoring applying such rule for M-1 activated TCI states, M being a positive integer. As illustrated, at a time window Ti, the active TCI state may be with an index 0, and the QCL source RS may be with an index “CSI-RS#a”.Table 1

[0083] In some example embodiments, if the TCI state activation includes X active QCL source RS resources for the first time duration, the first apparatus 110 may select those RS sources for determining the first subset of Set A. Similarly, the second subset is determined based on the active QCL source RS sources for the second time duration.

[0084] Alternatively, or in addition, in some example embodiments, the set of TCI states may be indicated or updated by the second apparatus 120 for the first apparatus 110. A different set of transmission configuration indicator states may be associated with each time duration of a number of consecutive time durations among the plurality of time durations. Likewise, the rule may be defined to select a QCL source RS included in the indicated or updated TCI state(s) instead of activated TCI state(s). Table 2 shows an example of defining subset of Set A for performance monitoring applying such rule for M-1 activated TCI states, M being a positive integer. As illustrated, at a time window Ti, the active TCI state may be with an index 0, and the QCL source RS may be with an index “CSI-RS#a”.Table 2

[0085] It is to be understood that the TCI index, the QCL source RS index and other parameters or values shown in Table 1 and Table 2 are only for the purpose of illustration, without suggesting any limitations. Any suitable subset of RSs with any suitable indices may be defined. It is also to be understood that although the RSs shown in Table 1 and Table 2 are CSI-RS, in some example embodiments, the RSs may be any other suitable RSs. Scope of embodiments of the present disclosure is not limited in this regard.

[0086] In some example embodiments, the second apparatus 120 may transmit, to the first apparatus 110, a plurality of updated TCI states. The first apparatus 110 may receive the plurality of updates TCI states. Assuming TN time instance in future, for latest monitoring RS resources (for example, determined based on updated TCI states), it is possible that another updated activated TCI state is associated to a second future time instance. Similarly, the updated activated TCI state associated to N future time instance may be different from earlier N-1 time instances.

[0087] In some example embodiments, the first apparatus 110 may discard a previous measurement result associated with a subset of the set of reference signals. If the activated TCI state is updated in next future time instance(s), the first apparatus 110 is expected to consider the latest monitoring RS resources (for example, determined based on the updated TCI state) and discard any monitoring metric calculations or monitoring outcomes which are ongoing based on an earlier monitoring RS resources.

[0088] The first apparatus 110 performs (250), based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations. That is, for performance monitoring, the first apparatus 110 may use thedetermined monitoring RS resources based on the first and second indications and / or rules.

[0089] In some example embodiments, the first apparatus 110 may determine, based on the first and second indications and the rule, the subset of the set of reference signals to be monitored in the time duration of the plurality of time durations. The first apparatus 110 may use the determined subset of set of RSs for the performance monitoring.

[0090] In some example embodiments, the first apparatus 110 may transmit, to the second apparatus 120, a measurement report based on the at least one measurement associated with the determined subset of set of RSs. The second apparatus 120 may receive the measurement report. The second apparatus 120 may determine one or more performance monitoring metrics based on the measurement report. That is, the first apparatus 110 may measure the corresponding RS resources of the subset(s) of Set A or Set A, and report the measurements to the second apparatus 120. The second apparatus 120 may perform the performance monitoring based on the measurements.

[0091] Alternatively, in some example embodiments, the first apparatus 110 may determine one or more performance monitoring metrics based on the one or more measurements. For example, the first apparatus 110 may measure the corresponding RS resources of the subset(s) of Set A or Set A, and derive the monitoring metrics or monitoring outcome. The first apparatus 110 may transmit the one or more performance monitoring metrics to the second apparatus 120.

[0092] As mentioned, the first apparatus 110 and / or the second apparatus 120 may determine one or more performance monitoring metrics (also referred to as performance metrics / KPIs). By way of example, the performance monitoring metric(s) may include at least one of the following:- beam prediction accuracy related key performance indicators (KPIs), such as Top-K (K being a positive integer) or Top-1 beam prediction accuracy,- link quality related KPIs, such as throughput, layer one (L1)-RSRP, L1 -signal to interference plus noise ratio (SINR), hypothetical block error ratio (BLER),- performance metric based on input / output data distribution of AI / ML, or- L1-RSRP difference evaluated by comparing measured RSRP and predicted RSRP.

[0093] Several example embodiments regarding reference signal measurement for performance monitoring have been described with respect to FIG. 2. With these embodiments, the first apparatus 110 can determine which subset of the set of RSs is applicable to the performance monitoring. The performance monitoring can thus be performed on the determined subset of RSs. The resource utilization can thus be improved, and power consumption can be reduced. In addition, such procedure is simple and not involve a large amount of signaling. That is, the signaling overhead can be reduced.

[0094] Further example embodiments of reference signal measurement for performance monitoring will be described with respect to FIG. 3 and FIG. 4. FIG. 3 illustrates a signaling diagram 300 for reference signal measurement for performance monitoring according to some example embodiments of the present disclosure. The signaling diagram 300 involves the first apparatus 110 and the second apparatus 120 in FIG. 1. For purpose of discussion, some example embodiments are described where the first apparatus 110 is implemented as a terminal device and the second apparatus 120 is implemented as a network device.

[0095] In the description of FIG. 3, it is assumed that a model for temporal domain beam prediction (that is, BM-Case2) is implemented at the first apparatus 110. It is also assumed that the performance monitoring of the model is performed at the second apparatus 120. The signaling involved in the signaling diagram 300 may transmitted or received via any suitable signaling such as DCI, RRC or MAC CE.

[0096] As shown in FIG. 3, the second apparatus 120 transmits (305), to the first apparatus 110, a configuration of resources such as CSI-RS or SSB resources. The first apparatus 110 may receive (310) the configuration. For example, the configuration may include a nzp-CSI-RS- ResourceToAddModList.

[0097] The second apparatus 120 may transmit (315), to the first apparatus 120, a configuration of a beam prediction. The first apparatus 110 may receive (320) the configuration. That is, the second apparatus 120 may configure the first apparatus 110 to perform time / temporal domain beam prediction, and configure the first apparatus 110 to perform reporting of prediction results.

[0098] The first apparatus 110 may perform (325) the AI / ML based beam prediction. The first apparatus 110 may transmit (330) a measurement report to the second apparatus 120. The second apparatus 120 may receive (335) the measurement report. For example, the first apparatus 110 may report predicted Top-K beam ID(s) or Top-K predicted RSRP through CSI report to the second apparatus 120.

[0099] The second apparatus 120 may transmit (340), to the first apparatus 110, active TCI state(s) for DL / UL channels. The first apparatus 110 may receive (345) the active TCI state(s).

[0100] The second apparatus 110 transmits (350), to the first apparatus 110, a first indication (also referred to as a first trigger, or a first configuration) indicating that monitoring resource set based on subset of Set A are same or different subsets for the future time instances. The first apparatus 110 receives (355) the first indication.

[0101] The second apparatus 110 transmits (360), to the first apparatus 110, a second indication (also referred to as a second trigger or a second configuration) to further define rule(s). The first apparatus 110 receives (365) the second indication.

[0102] The first apparatus 110 may determine (370) monitoring RSs based on the rules. By way of example, for a first next future time instance, a subset of set A may be determined based on the QCL source of activate TCI states. For a second next future time instance, a corresponding subset of Set A may be determined based on QCL source of another activate TCI state.

[0103] In some example embodiments, the second apparatus 120 may transmit (375), to the first apparatus 110, DL RSs associated with future activate TCI states. The first apparatus 110 may receive (380) the DL RSs.

[0104] In some example embodiments, a UE-assisted or NW-sided performance monitoring may be performed (385) based on the monitoring RSs associated with subset of Set A.

[0105] In some example embodiments, the second apparatus 120 may update the active TCI state(s) for DL or UL channels. The second apparatus 120 may transmit (390), to the first apparatus 110, the updated TCI state(s). The first apparatus 110 may receive (395) the activated TCI state (s).

[0106] In some example embodiments, the transmitting (360) of the second indication, the determining (370) of the monitoring RSs and the transmitting (375) of the DL RSs may be repeated based on the updated active TCI states.

[0107] With these embodiments, the first apparatus 110 can determine which subset of the set of RSs is applicable to the performance monitoring. The performance monitoring can thus be performed on the determined subset of RSs. The resource utilization can thus be improved, and power consumption can be reduced. In addition, such procedure is simple and not involve a large amount of signaling. That is, the signaling overhead can be reduced.

[0108] FIG. 4 illustrates a signaling diagram 400 for reference signal measurement for performance monitoring according to some example embodiments of the present disclosure. The signaling diagram 400 involves the first apparatus 110 and the second apparatus 120 in FIG. 1. For purpose of discussion, some example embodiments are described where the first apparatus 110 is implemented as a terminal device and the second apparatus 120 is implemented as a network device. The signaling involved in the signaling diagram 300 may transmitted or received via any suitable signaling such as DCI, RRC or MAC CE.

[0109] In the description of FIG. 4, it is assumed that a model for temporal domain beam prediction (that is, BM-Case2) is implemented at the second apparatus 120. It is also assumed that the performance monitoring of the model is performed at the second apparatus 120.

[0110] As shown in FIG. 4, the second apparatus 120 transmits (405), to the first apparatus 110, a configuration of resources such as CSI-RS or SSB resources. The first apparatus 110 may receive (410) the configuration. For example, the configuration may include a nzp-CSI-RS-ResourceToAddModList.

[0111] The second apparatus 120 may perform (415) an AI / ML based beam prediction, such as Beam-Case 2. The second apparatus 120 may transmit (425), to the first apparatus 110, active TCI states for DL / UL channels. The first apparatus 110 may receive (430) the active TCI states.

[0112] The second apparatus 120 transmits (430), to the first apparatus 110, a first indication indicating that monitoring resource set based on subset of Set A are same or different subsets for the future time instances. The first apparatus 110 receives (435) the first indication.

[0113] The second apparatus 120 transmits (440), to the first apparatus 110, a second indication that at least one rule is applied to determine the subset of Set A. That is, the second indication may further define the rule(s). The first apparatus 110 receives (445) the second indication.

[0114] The first apparatus 110 determines (450) monitoring RSs (such as exact monitoring RSs) based on the rule(s). For example, for a next future time instance, the subset of set A may be determined based on the QCL source of activate TCI states. For a second next future time instance, the corresponding subset of Set A may be determined based on QCL source of another activate TCI state.

[0115] In some example embodiments, the second apparatus 120 may transmit (455), to the first apparatus 110, DL RSs associated with future activate TCI states. The first apparatus 110 may receive (460) the DL RSs.

[0116] The first apparatus 110 may transmit (465), to the second apparatus 120, the subset of Set A based on the RS resources. The second apparatus 120 may receive (470) the subset of Set A. The second apparatus 120 may perform (475) the performance monitoring such as NW-sided performance monitoring based on the monitoring RS resources associated with subset of Set A.

[0117] In some example embodiments, the second apparatus 120 may update the TCI state(s) for UL or DL channels. The second apparatus 120 may transmit (480) the updated TCI state(s) for UL or DL channels to the first apparatus 110. The first apparatus 110 may receive (485) the updated TCI states.

[0118] In some example embodiments, several operations described with respect to FIG. 4 will be repeated. For example, with the received updated TCI state, the determining (450) of the monitoring RS(s), the transmitting (455) of the DL RSs, the transmitting (465) of the subset of Set A, and / or the performing (475) of the performance monitoring may be repeated.

[0119] With these embodiments, the first apparatus 110 can determine which subset of the set of RSs is applicable to the performance monitoring. The performance monitoring can thus be performed on the determined subset of RSs. The resource utilization can thus be improved, andpower consumption can be reduced. In addition, such procedure is simple and not involve a large amount of signaling. That is, the signaling overhead can be reduced.

[0120] FIG. 5 shows a flowchart of an example method 500 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 500 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0121] At block 510, first apparatus 110 receives, from a second apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations.

[0122] At block 520, first apparatus 110 receives, from the second apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations.

[0123] At block 530, first apparatus 110 performs, based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations.

[0124] In some example embodiments, the method 500 further comprises: receiving, from the second apparatus, a third indication whether a different subset of the set of reference signals are applicable for each time duration of the plurality of time durations.

[0125] In some example embodiments, a plurality of sets of reference signal indices received for a plurality of subsets of the set of reference signals indicates that a different subset from the plurality of subsets of the set of reference signals are applicable in each time duration of the plurality of time durations.

[0126] In some example embodiments, the plurality of sets of reference signal indices are received in a medium access control message.

[0127] In some example embodiments, the at least one rule comprises a rule that a set of quasi co-located source reference signals are determined for a respective subset of the set of reference signals applied to each time duration of the plurality of time durations, based on association between the time duration and a set of transmission configuration indicator states corresponding to the set of quasi co-located source reference signals.

[0128] In some example embodiments, the set of transmission configuration indicator states are activated, indicated or updated by the second apparatus for the first apparatus.

[0129] In some example embodiments, a different set of transmission configuration indicator states are associated with each time duration of a number of consecutive time durations among the plurality of time durations.

[0130] In some example embodiments, the method 500 further comprises: receiving, from the second apparatus, a plurality of updated transmission configuration indicator states; and discarding a previous measurement result associated with a subset of the set of reference signals.

[0131] In some example embodiments, the method 500 further comprises: determining, based on the first and second indications and the rule, the subset of the set of reference signals to be monitored in the time duration of the plurality of time durations.

[0132] In some example embodiments, the method 500 further comprises: transmitting, to the second apparatus, a measurement report based on the at least one measurement.

[0133] In some example embodiments, the method 500 further comprises: determining one or more performance monitoring metrics based on the one or more measurements; and transmitting the one or more performance monitoring metrics to the second apparatus.

[0134] In some example embodiments, the set of reference signals comprise a set of predicted reference signals.

[0135] FIG. 6 shows a flowchart of an example method 600 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0136] At block 610, the second apparatus 120 transmits, to a first apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations.

[0137] At block 620, the second apparatus 120 transmits, to the first apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations.

[0138] In some example embodiments, the method 600 further comprises: transmitting, to the first apparatus, a third indication whether a different subset of the set of reference signals are applicable for each time duration of the plurality of time durations.

[0139] In some example embodiments, a plurality of sets of reference signal indices for a plurality of subsets of the set of reference signals is transmitted to the first apparatus to indicate that a different subset from the plurality of subsets of the set of reference signals are applicable in each time duration of the plurality of time durations.

[0140] In some example embodiments, the plurality of sets of reference signal indices are transmitted in a medium access control message.

[0141] In some example embodiments, the at least one rule comprises a rule that a set of quasi co-located source reference signals are determined for a respective subset of the set of referencesignals applied to each time duration of the plurality of time durations, based on association between the time duration and a set of transmission configuration indicator states corresponding to the set of quasi co-located source reference signals.

[0142] In some example embodiments, the set of transmission configuration indicator states are activated, indicated or updated by the second apparatus for the first apparatus.

[0143] In some example embodiments, a different set of transmission configuration indicator states are associated with each time duration of a number of consecutive time durations among the plurality of time durations.

[0144] In some example embodiments, the method 600 further comprises: transmitting, to the first apparatus, a plurality of updated transmission configuration indicator states.

[0145] In some example embodiments, the method 600 further comprises: receiving a measurement report from the first apparatus, the measurement report being based on at least one measurement associated with a subset of the set of reference signals; and determining one or more performance monitoring metrics based on the measurement report.

[0146] In some example embodiments, the method 600 further comprises: receiving, from the first apparatus, one or more performance monitoring metrics associated with a subset of the set of reference signals.

[0147] In some example embodiments, the set of reference signals comprise a set of predicted reference signals.

[0148] In some example embodiments, a first apparatus capable of performing any of the method 500 (for example, the first apparatus 110 in FIG. 1 ) may comprise means for performing the respective operations of the method 500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1 .

[0149] I n some example embodiments, the first apparatus comprises means for receiving, from a second apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; means for receiving, from the second apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations; and means for performing, based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations.

[0150] I n some example embodiments, the first apparatus may further comprise means for receiving, from the second apparatus, a third indication whether a different subset of the set of referencesignals are applicable for each time duration of the plurality of time durations.

[0151] I n some example embodiments, a plurality of sets of reference signal indices received for a plurality of subsets of the set of reference signals indicates that a different subset from the plurality of subsets of the set of reference signals are applicable in each time duration of the plurality of time durations.

[0152] In some example embodiments, the plurality of sets of reference signal indices are received in a medium access control message.

[0153] I n some example embodiments, the at least one rule comprises a rule that a set of quasi colocated source reference signals are determined for a respective subset of the set of reference signals applied to each time duration of the plurality of time durations, based on association between the time duration and a set of transmission configuration indicator states corresponding to the set of quasi co-located source reference signals.

[0154] I n some example embodiments, the set of transmission configuration indicator states are activated, indicated or updated by the second apparatus for the first apparatus.[O155]I n some example embodiments, a different set of transmission configuration indicator states are associated with each time duration of a number of consecutive time durations among the plurality of time durations.

[0156] I n some example embodiments, the first apparatus may further comprise means for receiving, from the second apparatus, a plurality of updated transmission configuration indicator states; and means for discarding a previous measurement result associated with a subset of the set of reference signals.[0i57]ln some example embodiments, the first apparatus may further comprise means for determining, based on the first and second indications and the rule, the subset of the set of reference signals to be monitored in the time duration of the plurality of time durations.[0i58]ln some example embodiments, the first apparatus may further comprise means for transmitting, to the second apparatus, a measurement report based on the at least one measurement.[0i59]ln some example embodiments, the first apparatus may further comprise means for determining one or more performance monitoring metrics based on the one or more measurements; and means for transmitting the one or more performance monitoring metrics to the second apparatus.[0i60]ln some example embodiments, the set of reference signals comprise a set of predicted reference signals.

[0161] In some example embodiments, a second apparatus capable of performing any of themethod 600 (for example, the second apparatus 120 in FIG. 1 ) may comprise means for performing the respective operations of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0162] In some example embodiments, the second apparatus comprises means for transmitting, to a first apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; and means for transmitting, to the first apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations.[0i63]ln some example embodiments, the second apparatus may further comprise means for transmitting, to the first apparatus, a third indication whether a different subset of the set of reference signals are applicable for each time duration of the plurality of time durations.

[0164] I n some example embodiments, a plurality of sets of reference signal indices for a plurality of subsets of the set of reference signals is transmitted to the first apparatus to indicate that a different subset from the plurality of subsets of the set of reference signals are applicable in each time duration of the plurality of time durations.[0i65]ln some example embodiments, the plurality of sets of reference signal indices are transmitted in a medium access control message.

[0166] I n some example embodiments, the at least one rule comprises a rule that a set of quasi colocated source reference signals are determined for a respective subset of the set of reference signals applied to each time duration of the plurality of time durations, based on association between the time duration and a set of transmission configuration indicator states corresponding to the set of quasi co-located source reference signals.

[0167] I n some example embodiments, the set of transmission configuration indicator states are activated, indicated or updated by the second apparatus for the first apparatus.[0i68]ln some example embodiments, a different set of transmission configuration indicator states are associated with each time duration of a number of consecutive time durations among the plurality of time durations.[0i69]ln some example embodiments, the second apparatus may further comprise means for transmitting, to the first apparatus, a plurality of updated transmission configuration indicator states. [0i70]ln some example embodiments, the second apparatus may further comprise means for receiving a measurement report from the first apparatus, the measurement report being based on at least one measurement associated with a subset of the set of reference signals; and means fordetermining one or more performance monitoring metrics / KPIs based on the measurement report. [0i7i]ln some example embodiments, the second apparatus may further comprise means for receiving, from the first apparatus, one or more performance monitoring metrics associated with a subset of the set of reference signals.[0i72]ln some example embodiments, the set of reference signals comprise a set of predicted reference signals.

[0173] FIG. 7 is a simplified block diagram of a device 700 that is suitable for implementing example embodiments of the present disclosure. The device 700 may be provided to implement a communication device, for example, the first apparatus 110 or the second apparatus 120 as shown in FIG. 1. As shown, the device 700 includes one or more processors 710, one or more memories 720 coupled to the processor 710, and one or more communication modules 740 coupled to the processor 710.

[0174] The communication module 740 is for bidirectional communications. The communication module 740 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 740 may include at least one antenna.

[0175] The processor 710 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 700 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0176] The memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 724, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random-access memory (RAM) 722 and other volatile memories that will not last in the power-down duration.

[0177] A computer program 730 includes computer executable instructions that are executed by the associated processor 710. The instructions of the program 730 may include instructions for performing operations / acts of some example embodiments of the present disclosure. The program 730 may be stored in the memory, e.g., the ROM 724. The processor 710 may perform any suitableactions and processing by loading the program 730 into the RAM 722.

[0178] The example embodiments of the present disclosure may be implemented by means of the program 730 so that the device 700 may perform any process of the disclosure as discussed with reference to FIG. 2 to FIG. 6. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0179] In some example embodiments, the program 730 may be tangibly contained in a computer readable medium which may be included in the device 700 (such as in the memory 720) or other storage devices that are accessible by the device 700. The device 700 may load the program 730 from the computer readable medium to the RAM 722 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0180] FIG. 8 shows an example of the computer readable medium 800 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 800 has the program 730 stored thereon.

[0181] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. Although various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as nonlimiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0182] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non- transitory computer readable medium. The computer program product includes computerexecutable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may beexecuted within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0183] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0184] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0185] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0186] Further, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of a single embodiment may also be implemented in a plurality of embodiments separately or in any suitable sub-combination.

[0187] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

CLAIMS1. A first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from a second apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; receive, from the second apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations; and perform, based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations.

2. The first apparatus of claim 1 , wherein the at least one memory and the at least one processor further cause the first apparatus to: receive, from the second apparatus, a third indication whether a different subset of the set of reference signals are applicable for each time duration of the plurality of time durations.

3. The first apparatus of claim 1 or 2, wherein a plurality of sets of reference signal indices received for a plurality of subsets of the set of reference signals indicates that a different subset from the plurality of subsets of the set of reference signals are applicable in each time duration of the plurality of time durations.

4. The first apparatus of claim 3, wherein the plurality of sets of reference signal indices are received in a medium access control message.

5. The first apparatus of any of claims 1 to 4, wherein the at least one rule comprises a rule that a set of quasi co-located source reference signals are determined for a respective subset of the set of reference signals applied to each time duration of the plurality of time durations, based on association between the time duration and a set of transmission configuration indicator states corresponding to the set of quasi co-located source reference signals.

6. The first apparatus of claim 5, wherein the set of transmission configuration indicator states are activated, indicated or updated by the second apparatus for the first apparatus.

7. The first apparatus of claim 5 or 6, wherein a different set of transmission configuration indicator states are associated with each time duration of a number of consecutive time durations among the plurality of time durations.

8. The first apparatus of any of claims 5 to 7, wherein at least one memory and the at least one processor further cause the first apparatus to: receive, from the second apparatus, a plurality of updated transmission configuration indicator states; and discard a previous measurement result associated with a subset of the set of reference signals.

9. The first apparatus of any of claims 1 to 8, wherein at least one memory and the at least one processor further cause the first apparatus to: determine, based on the first and second indications and the rule, the subset of the set of reference signals to be monitored in the time duration of the plurality of time durations.

10. The first apparatus of any of claims 1 to 9, wherein at least one memory and the at least one processor further cause the first apparatus to: transmit, to the second apparatus, a measurement report based on the at least one measurement.11 . The first apparatus of any of claims 1 to 9, wherein at least one memory and the at least one processor further cause the first apparatus to: determine one or more performance monitoring metrics based on the one or more measurements; and transmit the one or more performance monitoring metrics to the second apparatus.

12. The first apparatus of any of claims 1 to 11 , wherein the set of reference signals comprise a set of predicted reference signals.

13. A second apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor,cause the second apparatus at least to: transmit, to a first apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; and transmit, to the first apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations.

14. The second apparatus of claim 13, wherein the at least one memory and the at least one processor further cause the second apparatus to: transmit, to the first apparatus, a third indication whether a different subset of the set of reference signals are applicable for each time duration of the plurality of time durations.

15. The second apparatus of claim 13 or 14, wherein a plurality of sets of reference signal indices for a plurality of subsets of the set of reference signals is transmitted to the first apparatus to indicate that a different subset from the plurality of subsets of the set of reference signals are applicable in each time duration of the plurality of time durations.

16. The second apparatus of claim 15, wherein the plurality of sets of reference signal indices are transmitted in a medium access control message.

17. The second apparatus of any of claims 13 to 16, wherein the at least one rule comprises a rule that a set of quasi co-located source reference signals are determined for a respective subset of the set of reference signals applied to each time duration of the plurality of time durations, based on association between the time duration and a set of transmission configuration indicator states corresponding to the set of quasi co-located source reference signals.

18. The second apparatus of claim 17, wherein the set of transmission configuration indicator states are activated, indicated or updated by the second apparatus for the first apparatus.

19. The second apparatus of claim 17 or 18, wherein a different set of transmission configuration indicator states are associated with each time duration of a number of consecutive time durations among the plurality of time durations.

20. The second apparatus of any of claims 17 to 19, wherein at least one memory and the at least one processor further cause the second apparatus to: transmit, to the first apparatus, a plurality of updated transmission configuration indicator states.21 . The second apparatus of any of claims 13 to 20, wherein at least one memory and the at least one processor further cause the second apparatus to: receive a measurement report from the first apparatus, the measurement report being based on at least one measurement associated with a subset of the set of reference signals; and determine one or more performance monitoring metrics based on the measurement report.

22. The second apparatus of any of claims 13 to 20, wherein at least one memory and the at least one processor further cause the second apparatus to: receive, from the first apparatus, one or more performance monitoring metrics associated with a subset of the set of reference signals.

23. The second apparatus of any of claims 13 to 22, wherein the set of reference signals comprise a set of predicted reference signals.

24. A method comprising: receiving, at a first apparatus from a second apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; receiving, from the second apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations; and performing, based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations.

25. A method comprising: transmitting, at a second apparatus to a first apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; and transmitting, to the first apparatus, a second indication that at least one rule is applied todetermine a subset of the set of reference signals for each time duration of the plurality of time durations.

26. A first apparatus comprising: means for receiving, from a second apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; means for receiving, from the second apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations; and means for performing, based on the first and second indications, at least one measurement for a subset of the set of reference signals in a time duration of the plurality of time durations.

27. A second apparatus comprising: means for transmitting, to a first apparatus, a first indication that performance monitoring is based on a measurement associated with a subset of a set of reference signals, the set of reference signals being applied across a plurality of time durations; and means for transmitting, to the first apparatus, a second indication that at least one rule is applied to determine a subset of the set of reference signals for each time duration of the plurality of time durations.

28. A computer readable medium comprising instructions stored thereon for causing an apparatus at least to perform the method of claim 24 or the method of claim 25.

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