WO2025209706A1

WO2025209706A1 - Measurement reporting

Info

Publication number: WO2025209706A1
Application number: PCT/EP2025/053569
Authority: WO
Inventors: Fanny JARDEL; Filippo Tosato; Rana Ahmed; Luis Alberto SUAREZ RIVERA
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2024-04-04
Filing date: 2025-02-11
Publication date: 2025-10-09
Anticipated expiration: 2026-10-04
Also published as: GB2640167A

Abstract

Example embodiments of the present disclosure relate to a solution for measurement reporting In an aspect, a terminal device receives, from a network device, a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising the condition to determine whether a calibration measurement for a CSI-RS resource or resource set is invalid. The terminal device further determines based on the CSI report configuration a CSI report associated with the calibration measurements for the plurality of CSI- RS resources or resource sets. The terminal device further transmits to the network device the CSI report. In this way, a condition may be introduced for determining whether a calibration measurement is invalid or not sufficiently accurate, thereby improving the accuracy of the reported measurements and ensuring reliable report regardless of the terminal device implementation.

Description

MEASUREMENT REPORTING

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of GB application No.2404780.5, filed April 04, 2024. The content of which are hereby incorporated by reference in their entirety.

FIELD

[0002] Various example embodiments relate to the field of communication and in particular, to devices, methods, apparatuses and computer readable storage media for measurement reporting.

BACKGROUND

[0003] A communication network can be seen as a facility that enables communications between two or more communication devices, or provides communication devices access to a data network. A mobile or wireless communication network is one example of a communication network.

[0004] Such communication networks operate in according with standards such as those provided by 3GPP (Third Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). Examples of standards are the so-called 5G (5th Generation) standards provided by 3GPP.

SUMMARY

[0005] In general, example embodiments of the present disclosure provide a solution for measurement reporting, especially, for invalid measurement reporting for terminal device-assisted cooperative joint transmission (CJT) calibration.

[0006] In a first aspect, there is provided a terminal device. The first device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, from a network device, a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; determine, based on the CSI report configuration, a CSI report associated with the calibration measurements for the plurality of CSI-RS resources or resource sets; and transmit, to the network device, the CSI report. i [0007] In a second aspect, there is provided a network device. The network device may comprise: at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: determine a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition for a terminal device to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; and transmit, to the terminal device, the CSI report configuration; and receive, from the terminal device, the CSI report associated with the calibration measurements.

[0008] In a third aspect, there is provided a method. The method may comprise: receiving, from a network device, a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; determining, based on the CSI report configuration, a CSI report associated with the calibration measurements for the plurality of CSI-RS resources or resource sets; and transmitting, to the network device, the CSI report.

[0009] In a fourth aspect, there is provided a method. The method may comprise: determining a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition for a terminal device to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; and transmitting, to the terminal device, the CSI report configuration; and receiving, from the terminal device, the CSI report associated with the calibration measurements.

[0010] In a fifth aspect, there is provided an apparatus. The apparatus may comprise: means for receiving, from a network device, a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; means for determining, based on the CSI report configuration, a CSI report associated with the calibration measurements for the plurality of CSI- RS resources or resource sets; and means for transmitting, to the network device, the CSI report.

[0011] In a sixth aspect, there is provided an apparatus. The apparatus may comprise: means for determining a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition for a terminal device to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; means for transmitting, to the terminal device, the CSI report configuration; and means for receiving, from the terminal device, the CSI report associated with the calibration measurements.

[0012] In a seventh aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to third or fourth aspect.

[0013] In an eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to perform at least the method according to third or fourth aspect.

[0014] In a ninth aspect, there is provided a terminal device. The terminal device may comprise: receiving circuitry for receiving, from a network device, a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; determining circuitry for determining, based on the CSI report configuration, a CSI report associated with the calibration measurements for the plurality of CSI-RS resources or resource sets; and transmitting circuitry for transmitting, to the network device, the CSI report.

[0015] In a tenth aspect, there is provided a network device. The network device may comprise: determining circuitry for determining a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition for a terminal device to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; transmitting circuitry for transmitting, to the terminal device, the CSI report configuration; and receiving circuitry for receiving, from the terminal device, the CSI report associated with the calibration measurements.

[0016] 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

[0017] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0018] Fig. 1 illustrates an example of a network environment in which some embodiments of the present disclosure may be implemented; [0019] Fig. 2 illustrates an example signaling process for calibration measurement reporting in accordance with some embodiments of the present disclosure;

[0020] Fig. 3A to Fig. 3C illustrate a first example for determining the invalid status of calibration measurements and the related CSI report according to some embodiments of the present disclosure;

[0021] Fig. 4A to Fig. 4C illustrate a second example for determining the invalid status of calibration measurements and the related CSI report according to some embodiments of the present disclosure;

[0022] Fig. 5A illustrates an example signaling process for calibration measurement reporting in accordance with some embodiments of the present disclosure, in which the reference resource or resource set is selected as the resource or resource set with the smallest offset and not invalid measurement;

[0023] Fig. 5B illustrates an example signaling process for calibration measurement reporting in accordance with some embodiments of the present disclosure, in which all calibration quantities are reported along with invalid state indication;

[0024] Fig. 5C illustrates an example signaling process for calibration measurement reporting in accordance with some embodiments of the present disclosure, in which the calibration quantities for the selected TRPs are reported;

[0025] Fig. 6 illustrates a flowchart of an example method implemented at a terminal device in accordance with some embodiments of the present disclosure;

[0026] Fig. 7 illustrates a flowchart of an example method implemented at a network device in accordance with some embodiments of the present disclosure;

[0027] Fig. 8 illustrates a simplified block diagram of a device that is suitable for implementing some embodiments of the present disclosure; and

[0028] Fig. 9 illustrates a block diagram of an example of a computer-readable medium in accordance with some embodiments of the present disclosure.

[0029] Throughout the drawings, the same or similar reference numerals represent the same or similar elements.

DETAILED DESCRIPTION

[0030] Principles 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. The disclosure described herein may be implemented in various manners other than the ones described below.

[0031] 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.

[0032] 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.

[0033] It shall be understood that although the terms “first” and “second” etc. 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.

[0034] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes”, “including”, “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. As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” 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.

[0035] As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable):

(I) a combination of analog and/or digital hardware circuit(s) with software/firmware and

(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0036] 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.

[0037] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as 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 (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the future 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. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0038] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

[0039] 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 (Vol P) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0040] With the development of communication technology, coherent joint transmission (CJT) is introduced, in which multiple transmission points (such as base stations or antennas) work together to coherently send the same data stream to the same UE. The purpose of this technology is to improve signal quality, enhance coverage and increase system capacity. However, when these transmission points are distributed in different geographical locations (i.e., deployed between sites), differences in signal propagation delays and the like may lead to complex channel conditions, which in turn affects the performance of CJTs.

[0041] UE-assisted CJT calibration is a new feature that is being introduced in Release 19. A UE can be configured to report some following measurement to the network to help with CJT calibration: intertransmission and receiving point (TRP) delay offset, frequency offset and phase offset reporting. That is to say, the UE is able to measure the propagation delay, phase and frequency differences of signals received from various TRPs and feed this information back to the network. The network can then use this feedback information to adjust transmission parameters to reduce delay differences, synchronization phase and frequency, thereby optimizing the performance of the CJT. However, there are some issues for the measurement report for UE-assisted CJT calibration to be solved. Further, some measurement for some TRPs may be not sufficiently accurate, and the report needs to ensure that all reported measurements have good signal quality. Further, the UE dynamic indication of TRP selection renders the need to introduce a variable-size Part 2 in the CSI report, alongside a fixed-size Part 1 where the TRP selection indication is reported, thereby rendering more complex logic and algorithm for dynamically constructing and generating CSI reports of different sizes and the like.

[0042] In view of the above, some embodiments of the present disclosure propose a solution for measurement reporting, for example, invalid measurement reporting for terminal device-assisted CJT calibration. In some example embodiments of the present disclosure, the terminal device receives, from a network device, a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; determines, based on the CSI report configuration, a CSI report associated with the calibration measurements for the plurality of CSI-RS resources or resource sets; and transmits, to the network device, the CSI report. In this way, a condition may be introduced for determining whether a calibration measurement is invalid or not sufficiently accurate, thereby improving the accuracy of the reported measurement and ensuring that a same measurement is reported as invalid regardless of the terminal device implementation.

[0043] Fig. 1 illustrates an example network environment 100 in which example embodiments of the present disclosure may be implemented. The environment 100, which may be a part of a communication network, includes terminal devices and network devices. As illustrated in Fig. 1 , the communication network 100 may include a terminal device 110 (for example, a user equipment). The communication network 100 may further include a plurality of network devices 120, 130, and 140. The network devices 120, 130 and 140 may server respective areas 120-1 , 130-1, and 140-1 (also called as cells) using different frequency bands in both downlink communication and uplink communication between the terminal device 110 and the respective network device 120, 130, or 140.

[0044] It is to be understood that the number of network devices and terminal devices is given only for the purpose of illustration without suggesting any limitations. It should be understood that each network device may serve a plurality of cells, and only one cell is shown for each network device for the purpose of illustration. The system 100 may include any suitable number of network devices and/or terminal devices adapted for implementing embodiments ofthe present disclosure. Although notshown, it would be appreciated that one or more terminal devices may be located in the environment 100.

[0045] Communications in the network environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, the third generation (3G), the fourth generation (4G), the fifth generation (5G) or beyond, 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: multiple-input multiple-output (MIMO), orthogonal frequency division multiplexing (OFDM), time division multiplexing (TDM), frequency division multiplexing (FDM), code division multiplexing (CDM), Bluetooth, ZigBee, and machine type communication (MTC), enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra-reliable low latency communication (LIRLLC), carrier aggregation (CA), dual connection (DC), and new radio unlicensed (NR-U) technologies.

[0046] It is to be understood that the number of devices and their connection relationships and types shown in Fig. 1 are for illustrative purposes only without suggesting any limitation. The communication system 100 may include any suitable number of devices adapted for implementing embodiments of the present disclosure.

[0047] As mentioned above, in CJT multiple transmission points (such as base stations or antennas, or TRPs) work together to coherently send the same data stream to the same UE. In CJT downlink transmission, one or more multiple input and multiple output (MIMO) layers are transmitted coherently from multiple TRPs, such that each layer is transmitted from all TRPs in the CJT TRP set, and layers fully overlap in time and frequency. To make this possible, TRPs (for example, the network devices 120, 130, and 140 of Fig. 1) need to be synchronized in time, frequency, and phase.

[0048] Release 19 NR is expected to introduce new specifications to support UE reporting of measurements that can assist with calibration between multiple TRPs for CJT with non-ideal backhaul and synchronization. In other words, UE-assisted CJT calibration is a new feature that is being introduced in Release 19. Some use cases have been agreed with respect to the measurements for inter-TRP delay offset reporting, frequency offset reporting, and phase offset reporting, and a UE can be configured to report these measurements to help with CJT calibration. UE-assisted CJT calibration is primarily targeting inter-site deployments where large propagation delays may cause large composite CJT channel delay spread, and frequency and phase synchronization cannot easily be performed over the backhaul.

[0049] To address issues created by large delay spread of the composite CJT channel, frequency offset differences between the TRPs and the UE and to avoid expensive redesign of the antenna arrays and the transmit and receive phase self-calibration mechanism for them, it was agreed in Release 19 to support UE standalone aperiodic reporting of inter-TRP delay, frequency offset, and phase offset. [0050] With regard to the Release 19 aperiodic standalone CJT calibration reporting, for pertransmission and reception point (TRP) delay offset reporting, the following use case has been agreed: (1) TRP selection, and (2) delay offset compensation for at least one TRP to ensure the CJT-composite delay spread does not exceed a pre-defined dynamic range/threshold. Further, for per-TRP frequency offset (FO) reporting, the following use case has been agreed: (1) TRP selection, and (2) per-TRP FO compensation at NW side. In addition to the already agreed use cases, the following use cases are assumed for per-TRP DL/UL Rx-Tx phase misalignment reporting: (1) TRP selection; and (2) per-TRP DL/UL Rx-Tx phase compensation at NW side for reciprocity (e.g. using both (channel state information reference signal (CSI-RS) and sounding reference signal (SRS) for measurement).

[0051] Further, in Released CJT CSI reporting, whereby a UE is configured to measure and report precoding matrix indicator (PM I) or channel quality indicator (CQI) or rank indication (Rl) for N_TRP TRPs, a UE may be configured to select N_o < N_TRP and report CSI for the selected TRPs. In this case the UE indicates the TRP selection in Part 1 CSI with an W_rRP-bit bitmap. Note that, from UE and specification perspective, a TRP corresponds to a CSI-RS resource configured in the resource set for channel measurement with N_TRP resources, or a CSI-RS resource set (for example for tracking) in the resource setting containing at least N_TRP resource sets and associated to the calibration reporting. Hence in the following, from UE perspective, the terms TRP and CSI-RS resources or resource sets may be used interchangeably. This UE selection of TRPs for CJT CSI reporting is typically based on RSRP measurement, such that the selected TRPs are expected to provide the largest possible link quality.

[0052] For the purpose of CJT calibration reporting, the following options have been decided by RAN1#116bis: option 1, the UE reports for all the configured NTRP non zero power (NZP) CSI-RS resources or resource sets; option 2, the UE reports for N out of NTRP NZP CSI-RS resources or resource sets where the selection of N resources or resource sets is dynamically signalled by the NW to the UE; and option 3, the UE reports for N out of NTRP NZP CSI-RS resources or resource sets where the selection of N resources or resource sets is performed by the UE and included in the CSI report.

[0053] For above-mentioned option 3, i.e., UE dynamic indication of TRP selection, a problem with it is the need to introduce a variable-size Part 2 in the CSI report alongside a fixed-size Part 1 where the TRP selection indication is reported, because the payload size depends on the number of selected TRPs. However, from the UE perspective, the CSI report with variable-size Part 2 alongside a fixed-size Part 1 will render a variable payload size. From the UE perspective, a variable payload size has some disadvantage, for example, the need for more complex logic and algorithm for dynamically constructing and generating CSI reports of different sizes, increasing process time or response time for additional calculation when reporting CSI report, increasing physical memory and power consumption, increasing error rate due to the increased complexity of the reporting format, and causing interoperability challenges due to inconsistent handling of variable payload size between different UE and network implementations, and the like. Therefore, there is a need for improved measurement report for UE-assisted CJT calibration.

[0054] Hereinafter, an example signal process 200 for calibration measurement reporting in accordance with some embodiments of the present disclosure will be described with reference to Fig. 2. For the purpose of discussion, the process 200 may be described with reference to Fig. 1 . The process 200 may involve the terminal device 110, and any of the network devices 120, 130, and 140, which serves the terminal device 110. It should be understood that the terminal device 201 is an example of the terminal device 110, and the network device 202 is an example of one of the network devices 120, 130, and 140, which serves the terminal device now. It would be appreciated that although the process 200 has been described in the communication environment 100 of Fig. 1 , this process may be likewise applied to other communication scenarios with similar issues.

[0055] As shown in Fig. 2, the network device 202 determines or configures (205) a CSI report configuration 203 associated with a plurality of CSI-RS resources or resource sets. In some embodiments, the configured CSI report configuration 203 comprises at least one condition for a terminal device to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid. Then, the network device 202 transmits (210) the CSI report configuration 203 to the terminal device 201, and the terminal device 201 receives (215) the CSI report configuration 203. Then, the terminal device 201 determines (220) based on the CSI report configuration 203, a CSI report 204 associated with the calibration measurements for the plurality of CSI- RS resources or resource sets. In some embodiments, the terminal device 201 may determine the CSI report at least by determining whether a calibration measurement is invalid based on the at least one condition. Then, the terminal device 201 transmits (225) the CSI report 204 to the network device 202, and the network device 202 receives (230) the CSI report 204.

[0056] In some embodiments, the at least one condition is associated with a configurable RSRP threshold with respect to a target RSRP among RSRPs of the plurality of CSI-RS resources or resource sets. For example, the target RSRP is the largest RSRP among RSRPs of the plurality of CSI-RS resources or resource sets. In these embodiments, the network device 202 may receive, from the terminal device 201, reference signal received powers (RSRPs) for the configured plurality of CSI-RS resources or resource sets; and then configure the RSRP threshold based on the RSRPs of the plurality of CSI-RS resources or resource sets. In these embodiments, the terminal device 201 determines that the calibration measurement of a respective CSI-RS resource or resource set is invalid based on determining that the RSRP of the respective CSI-RS resource or resource set is smaller than a difference between the target RSRP (for example, the largest RSRP among the RSRPs for the plurality of resources or resource sets) and the RSRP threshold. In these embodiments, the terminal device 201 then selects a CSI-RS resource or resource set with a target calibration measurement (for example, a smallest calibration measurement) among the calibration measurements that are not invalid as a reference CSI- RS resource or resource set. That is to say, the reference CSI-RS resource or resource is one of those having the valid calibration measurements. These embodiments may be applicable for inter-TRP frequency offset and phase offset.

[0057] In some embodiments, the at least one condition is associated with a configurable RSRP threshold with respect to a RSRP of a reference CSI resource or resource set selected from the plurality of CSI-RS resources or resource sets. In these embodiments, the network device 202 may receive, from the terminal device, RSRPs for the configured plurality of CSI-RS resources or resource sets; and then configure a RSRP threshold based on the RSRPs of the plurality of CSI-RS resources or resource sets. In these embodiments, the terminal device 201 may select the reference CSI resource or resource set having a target RSRP (for example, the largest RSRP); and then determine that the calibration measurement of a respective CSI-RS resource or resource set is invalid based on determining that the RSRP of the respective CSI-RS resource or resource set is smaller than a difference between the target RSRP of the reference CSI resource or resource set and the RSRP threshold. These embodiments may be applicable for inter-TRP frequency offset and phase offset.

[0058] In some embodiments, the at least one condition is associated with a configurable quantization range such that the invalidity of calibration measurement is associated with a calibration measurement out of the configurable quantization range. In some embodiments, the configurable quantization range is associated with a cyclic prefix (CP) length. These embodiments are applicable for the inter-TRP delay reporting, in which a TRP may be excluded if the relative delay plus delay spread measurement exceed a predetermined value, e.g. , the CP, and this value can be configured by the gNB for a given report. In these embodiments, the network device 202 may receive, from the terminal device 201 , delay measurements for the plurality of CSI-RS resources or resource sets. Then, the network device 202 can configure a quantization range based on the delay measurements of the plurality of CSI-RS resources or resource sets. The quantitation range may be associated with a cyclic prefix length.

[0059] In some embodiments, the calibration measurements are associated with a terminal deviceassisted CJT calibration to at least one CSI-RS resource or resource set, and the measured calibration measurements comprise the measurements for delay offset, frequency offset, or phase offset. In some embodiments, the reported calibration measurement in the CSI report indicates a frequency offset difference, a phase offset difference or a delay offset difference between a specific CSI-RS resource or resource set among the plurality of CSI-RS resources or resource sets and a reference CSI-RS resource or resource set selected from the plurality of CSI-RS resources or resource sets. That is to say, the reported measurement may be the relative calibration measurement, rather than the measured absolute delay offset, frequency offset, or phase offset.

[0060] It should be noted that this configurable condition was not needed, for example, in relation to TRP selection for CJT CSI reporting, because the report already includes an indication of the quality of the reported CSI, given by the CQI.

[0061] In some embodiments, the CSI report comprises at least one reported valid calibration measurement and at least one invalid state indication, and the number of the plurality of CSI-RS resources or resource sets is N, and the total number of reported calibration measurements comprising at least one valid calibration measurement and at least one invalid state indication corresponds to N-1 . In some embodiments, an invalid state of a specific calibration measurement is indicated by a codepoint of quantization indices of the calibration measurements. In this way, the terminal device 201 may report measurement for all configured resources or resource sets except for the measurement for the reference resource or resource set, if the measurement is relative to a reference, or anchor resource or resource set, and there is no need to dynamically indicate a selection of resources or resource sets.

[0062] By the process 200, the calibration measurement of the CSI resource or resource set may be determined to be valid or invalid based on the CSI report configuration, and a CSI report may be determined based on the CSI report configuration. In other words, the process 200 introduces a corresponding configuration parameter in the CSI report configuration for determining the condition by which the terminal device may report a measurement as invalid, and also introduces an “invalid” state associated with one of the quantization indices used to report a calibration measurement. Therefore, by introducing the CSI report configuration comprising the condition by which the terminal device may report a measurement as invalid, a terminal device may be allowed to indicate to the network device that some resources or resource sets or TRPs may be excluded from CJT transmission because the reported calibration measurements are not sufficiently accurate or not valid, thereby ensuring that the gNB can use the sufficiently accurate and valid reported calibration measurements.

[0063] Further, the terminal device may report UE reports measurements for all configured CSI-RS resources or resource sets except a reference resource or resource set, if the measurement is relative to a reference, or anchor resource/resource set, and there is thus no need for introducing dynamic resource or resource set or TRP selection indication by the terminal device which would require a variable-size Part 2 CSI. Therefore, the network-configured CSI report configuration comprising the condition may ensure that a same measurement is reported as invalid regardless of UE implementation. Further, the process 200 may also ensure that the reference resource or resource set selected and reported by the terminal device and used to report relative inter-TRP calibration measurements, has good signal quality. Although direct measurement of the reference TRP may be not reported, if the reference TRP has not a good enough signal quality, all the reported measurements may be unreliable.

[0064] Hereinafter, some example embodiments for determining the invalid status of calibration measurement and the related CSI report will be described with reference to Fig. 3A to Fig. 4C.

[0065] Fig. 3A to Fig. 3C illustrate a first example for determining the invalid status of calibration measurements and the related CSI report according to some embodiments of the present disclosure. Specifically, Fig. 3A to Fig. 3C illustrate an example of RSRP threshold configuration and inter-TRP frequency offset (FO) reporting with invalid state reporting according to some embodiments of the present disclosure.

[0066] In this first example embodiment, the gNB configures a condition as an RSRP threshold, RSRP_th, relative to the largest RSRP amongst the N_TRP configured resource or resource set. A UE reports the relative frequency offset of a CSI-RS resource or resource set, n, as “invalid” if the RSRP of CSI-RS resource or resource set n is lower than RSRP_th dBs relative to the maximum of the N_TRP measured RSRPs, RSRP_max. If the quantisation range ofthe relative frequency offset comprises only nonnegative values, [0, i4_P0], and the UE selects and reports the reference resource or resource sets, a UE would select the reference resource or resource set with the smallest measured frequency offset and with RSRP not smaller than (RSRP_max - RSRP_th j dB. This mechanism ensures that all the noninvalid reported frequency offsets are reliable, because both the reported CSI-RS resources or resource sets and the reference resource or resource set, which is not reported, have good enough signal quality. In some embodiments, the “invalid” state is associated to one of the quantization indices, for example, index 0, or index 2^B - 1, for a B-bit indication of a relative frequency offset measured on a CSI-RS resource or resource set, with respect to a reference resource or resource set.

[0067] Fig. 3A illustrates the configured quantization range for the frequency offset differences [0, A_P0] and the measured values of FOs for the 4 CSI-RS resources or resource sets. As shown in Fig. 3A, N_TRP - 4 CSI-RS resources or resource sets are configured for measurement and reporting of frequency offset differences between N_TRP - 1 resources or resource sets and a reference resource or resource set.

[0068] Fig. 3B illustrates the measured RSRP values and the configured RSRP threshold RSRP_th. As shown in Fig. 3B, the CSI-RS resources or resource sets 3 and 4 are reported as invalid because their RSRPs are smaller than (RSRP_max - RSRP_th) dB, where RSRP_max = RSRP₂. As sown in Fig. 3A, The selected reference resource or resource set (i.e., resource or resource set 1) is the one with lowest FO amongst the resources or resource sets within the range [ (RSRP_max - RSRP_th), RSRP_max],

[0069] Fig. 3C illustrates the quantization values reported for the N_TRP - 1 = 3 CSI-RS resources or resource sets other than or except for the reference. As shown in Fig. 3C, the FO difference or relative FO between resource or resource set 2 and the reference (i.e., resource or resource set 1) is reported, after quantization as Q FO₂ - FO-^), and the FO difference or relative FO between CSI-RS resource or resource set 3 or 4 and the reference is reported as invalid.

[0070] Fig. 4A to Fig. 4C illustrate a second example for determining the invalid status of calibration measurement and the related CSI report according to some embodiments of the present disclosure. Specifically, Fig. 4Ato Fig.4C illustrate an example of RSRP threshold configuration and inter-TRP phase offset (PO) reporting with invalid state reporting according to some embodiments of the present disclosure.

[0071] In this second example embodiment, the “invalid” state is associated to one of the quantisation indices, for example, index 0, or index 2^B - 1, for a B-bit indication of a relative phase offset measured on a CSI-RS resource or resource set, with respect to a reference resource or resource set. The gNB configures a condition as an RSRP threshold, RSRP_th, relative to the largest RSRP amongst the N_TRP configured resource or resource set. A DE reports the relative phase offset of a CSI-RS resource or resource set, n, as “invalid” if the RSRP of CSI-RS resource or resource set n is lower than RSRP_th dBs relative to the maximum of the N_TRP measured RSRPs, RSRP_max. If the quantisation range of the relative phase offset comprises only nonnegative values [0, A^], and the UE selects and reports the reference resource or resource sets, a UE would select the reference resource or resource set with the smallest measured phase offset and with RSRP not smaller than (RSRP_max - RSRP_th) dB. This mechanism ensures that all the non-invalid reported phase offsets are reliable, because both the reported CSI-RS resources or resource sets and the reference resource or resource set, which is not reported, have good enough signal quality.

[0072] Fig. 4A illustrates the configured quantization range for the phase offset (PO) differences [0, ] and the measured values of POs for the 4 CSI-RS resources or resource sets. Fig. 4B illustrates the measured RSRP values and the configured RSRP threshold RSRP_th. As shown in Fig. 4B, only one resource or resource set (i.e., resource or resource set 4) has an RSRP lower than the minimum configured value of (RSRP_max - RSRP_th) dB, and hence only one relative phase offset is reported as invalid. As shown in Fig. 4A, the reference CSI-RS resource or resource set is that of index 3 (i.e., resource or resource set 3), because it is the resource or resource set with the lowest measured phase offset with the RSRP within the configured range of RSRP. As shown in Fig. 4C, the first PO difference or first relative PO between resource or resource set 1 and the reference (i.e., resource or resource set 3) and the second PO difference or second relative PO between resource or resource set 2 and the reference are reported, after quantization as - <i ₃) and Q (<J ₂ - ^<t*3). and the PO difference or relative PO between CSI-RS resource or resource set 4 and the reference is reported as invalid.

[0073] In a third example embodiment, the “invalid” state is associated to one of the quantisation indices, for example, index 0, or index 2^B - 1, for a B-bit indication of a relative frequency offset measured on a CSI-RS resource or resource set, with respect to a reference resource or resource set. The gNB configures a condition as an RSRP threshold, RSRP_th, relative to the RSRP of the reference resource or resource set. A DE reports the relative frequency offset of a CSI-RS resource or resource set, n, as “invalid” if the RSRP of CSI-RS resource or resource set n is lower than RSRP_th dBs relative to the RSRP of the reference resource or resource set. This solution may be suitable if the quantisation range of the relative frequency offset includes both negative and non-negative values [-A_F0, A_FO] and the UE selects and reports the reference resource or resource sets. In this case the UE does not need to select the resource or resource set with the smallest measured FO, and the UE may select the strongest resource or resource set as reference, for example, resource or resource set having the largest RSRP.

[0074] In a fourth example embodiment (not shown), the “invalid” state is associated to one of the quantisation indices, for example, index 0, or index 2^B - 1, for a B-bit indication of a relative phase offset measured on a CSI-RS resource or resource set, with respect to a reference resource or resource set. The gNB configures a condition as an RSRP threshold, RSRP_tfl, relative to the RSRP of the reference resource or resource set. A UE reports the relative phase offset of a CSI-RS resource or resource set, n, as “invalid” if the RSRP of CSI-RS resource or resource set n is lower than RSRP_th dBs relative to the RSRP of the reference resource or resource set. This solution may be suitable if the quantisation range of the relative phase offset includes both negative and nonnegative values [-A_o, and the UE selects and reports the reference resource or resource sets. In this case the UE does not need to select the resource or resource set with the smallest measured phase offset, and the UE may select the strongest resource or resource set as reference, for example, resource or resource set having the largest RSRP.

[0075] In fifth embodiment example (not shown), the configurable condition associated to the invalid state can be understood to be defined by a parameter that configures the maximum and/or the minimum value of a quantisation range, such that the “invalid” state indicates an “out-of-range” state, i.e., that a measurement exceeds the configured boundaries of quantisation. This condition is applicable, for example, to inter-TRP delay reporting, where a TRP may be excluded if the relative delay plus delay spread measurement exceed a predetermined value, e.g., the cyclic prefix (CP), and this value can be configured by the gNB for a given report. For inter-TRP delay reporting, if the delay plus delay spread of a TRP with respect to a reference TRP exceeds a certain threshold, for example, the CP length, that TRP should be excluded from the CJT set because it causes inter-symbol interference. Conversely, for inter-TRP frequency offset and phase offset reporting, measurement noise may be of concern if the signal of CSI-RS resources or resource sets is received with low power.

[0076] According to the first to fifth examples, the UE may report measurements for all configured CSI- RS resources or resource sets except a reference resource or resource set, if the reported measurement is relative to a reference, or anchor resource or resource set, such as frequency offset difference, phase offset difference and delay offset difference between the specific resource or resource set and the reference resource and resource set. Therefore, there is no need to dynamically indicate a selection of resources or resource sets with a variable-size Part 2 CSI. The network-configured condition for determining the invalid measurement may ensure that a same measurement is reported as invalid regardless of UE implementation.

[0077] Fig. 5A illustrates an example signaling process 500A for calibration measurement reporting in accordance with some embodiments of the present disclosure, in which signaling process is applicable to the first and second examples as shown in Fig. 3A to Fig. 4C. It should be understood that the UE 501 is an example of the terminal device 110, and the gNB 502 is an example of one of the network devices 120, 130, and 140, which serves the terminal device now.

[0078] As shown in Fig. 5, at 51 OA, the gNB 502 configures CSI-RS signals (for example, a plurality of CSI-RS resources or resource sets) to be measured by the UE 501 , and the gNB 502 further configures the condition for determining the invalid delay offset /frequency offset /phase offset measurement(s) of the plurality of CSI-RS resources or resource sets. In some embodiments, the gNB configures a condition as an RSRP threshold, RSRP_tfl, relative to the largest RSRP amongst the N_TRP configured resource or resource set. In some embodiments, the gNB configures a condition as an RSRP threshold, RSRP_th, relative to the RSRP of a selected reference resource or resource set. In some embodiments, the configurable condition associated to the invalid state can be understood to be defined by a parameter that configures the maximum and/or the minimum value of a quantisation range, such that the “invalid” state indicates an “out-of-range” state, i.e., that a measurement exceeds the configured boundaries of quantisation. [0079] At 520A, the gNB 502 triggers the report from the UE 501. In some embodiments, the CSI report is the UE standalone aperiodic reporting of inter-TRP delay, frequency offset, and phase offset, and the report should be triggered by the gNB 502. At 530A, the UE 501 selects the reference resource or resource set from the plurality of CSI-RS resources or resource sets. In the illustrated embodiment, the CSI-RS resource or resource set, which has the smallest delay offset, frequency offset, or phase offset and is determined based on the condition to be not invalid, will be selected as the reference. In some embodiments (not shown), the CSI-RS resource or resource set, which has the target RSRP measurement (for example, the largest RSRP measurement) will be selected as the reference.

[0080] At 540A, the UE 501 reports the measured reference signals for the selected valid resource(s) or resource set(s) and the invalid state for the determined invalid measurement(s). That is to say, for the valid resource or resource set, the reference signal thereof will be reported, whereas for the invalid resources or resource set, the invalid state thereof will be reported. At 550A, based on the CSI-RS report, the gNB 502 applies the delay, frequency or phase calibration to TRPs (or the resources or resource sets) which are determined to be not invalid (i.e. valid).

[0081] By the process 500A, it introduces a corresponding configuration condition for determining whether a measurement is invalid, and also introduces an “invalid” state associated with one of the quantization indices used to report a calibration measurement. The UE can be allowed to indicate to the gNB about TRPs that may be excluded from CJT transmission because the reported calibration measurements are not sufficiently accurate and by doing so there is no need for introducing dynamic TRP selection indication by the UE which would require a variable-size Part 2 CSI. That is to say, the UE reports measurements for all configured CSI-RS resources or resource sets except a reference resource or resource set, if the reported measurement is relative to a reference, or anchor resource or resource set, and thus there is no need to dynamically indicate a selection of resources or resource sets. The network-configured condition ensures that a same measurement is reported as invalid regardless of UE implementation.

[0082] Fig. 5B illustrates an example signaling process 500B for calibration measurement reporting in accordance with some embodiments of the present disclosure, in which all calibration quantities are reported along with invalid state indication. It should be understood that the UE 501 is an example of the terminal device 110, and the gNB 502 is an example of one of the network devices 120, 130, and 140, which serves the terminal device now. This process 500B may be performed for the CJT calibration reporting defined in RAN1#116bis option 1 : the UE reports for all the configured NTRP non zero power (NZP) CSI-RS resources or resource sets. [0083] At 51 OB, the gNB 502 configures an RSRP related value, threshold p for all the TRPs. For example, the threshold p may be the RSRP_max - RSRP_th . The value of the threshold can be configured in RRC for example. At 520B, the gNB 502 transmits the configuration of this threshold p to the UE 501. At 530B, if the RSPR related value of a given TRP is less than the threshold p, the calibration measurement of this given TRP will be determined and then reported as invalid. At 540B, the UE 501 transmits a CSI report comprising all calibration quantities for the configured TRPs and the indication(s) of invalid state reporting to the gNB 502. At 550B, the gNB 502 may discard the measurement with invalid state for the associated TRPs.

[0084] In the process 500B, the CSI report may include all calibration quantities for the configured TRPs and indications on the calibration quantities which do not meet a certain threshold and can be reported with an “invalid state” indication. This could be done for instance by means of a bitmap indicating the TRPs with valid or invalid states. A second part of the CSI report would be the full set of calibration reporting quantities with a certain quantization format. Later on the network device may could do further determinations having all the calibration reporting quantities for each UE, for example, the network device may discard the measurement with invalid state for the associated TRPs.

[0085] Fig. 5C illustrates an example signaling process 500C for calibration measurement reporting in accordance with some embodiments of the present disclosure, in which the calibration quantities for the selected TRPs are reported. It should be understood that the UE 501 is an example of the terminal device 110, and the gNB 502 is an example of one of the network devices 120, 130, and 140, which serves the terminal device now. This process 500C may be performed for the CJT calibration reporting defined in RAN1#116bis option 3: the UE reports for N out of NTRP NZP CSI-RS resources or resource sets where the selection of N resources or resource sets is performed by the UE and included in the CSI report.

[0086] At 510C, the gNB 502 configures an RSRP related value, threshold for all the TRPs. For example, the threshold p may be the RSRP_max - RSRP_th . The value of the threshold can be configured in RRC for example. At 520C, the gNB 502 transmits the configuration of this threshold p to the UE 501 . At 530C, if the RSPR related value of a given TRP is less than the threshold p, this given TRP will be removed from the choices for the reported TRP subset. At 540C, the UE 501 transmits a CSI report comprising calibration quantities for the set of selected TRPs.

[0087] In the process 500C, with dynamic selection and reporting of TRPs by the terminal device, the condition for the “invalid” for the TRP selection is used, such that the invalid measurements are excluded from reporting and only the TRPs corresponding to the valid measurement are indicated and reported to the gNB. Therefore, in this case, threshold based selection of the TRPs and the reporting of the calibration quantities jointly takes place, and only a subset of the TRPs which meet the threshold for each UE is reported. This solution may automatically shape or select the TRP subset at least in a first calibration stage. Thus, the UE assist the network to choose the TRP set based on the RSRP threshold used for the first calibration stage, and the first calibration stage is accompanied with the corresponding calibration reporting quantities.

[0088] Fig. 6 illustrates a flowchart of an example method 600 implemented at a terminal device in accordance with some other embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the terminal device 110 with reference to Fig. 1.

[0089] At block 610, the terminal device 110 receives, from a network device, a CSI report configuration associated with a plurality of CSI-RS resources or resource sets, the CSI report configuration comprising at least one condition to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid. At block 620, the terminal device 110 determines, based on the CSI report configuration, a CSI report associated with the calibration measurements for the plurality of CSI-RS resources or resource sets. At block 630, the terminal device 110 transmits, to the network device, the CSI report.

[0090] In some embodiments, the terminal device may determine, based on the CSI report configuration the CSI report at least by determining whether a calibration measurement is invalid based on the at least one condition. In some embodiments, the at least one condition is associated with a configurable reference signal received power (RSRP) threshold with respect to a target RSRP among RSRPs of the plurality of CSI-RS resources or resource sets. In some embodiments, the terminal device may determine that the calibration measurement of a respective CSI-RS resource or resource set is invalid based on determining that the RSRP of the respective CSI-RS resource or resource set is smaller than a difference between the target RSRP and the RSRP threshold. In some embodiments, the target RSRP is the largest RSRP among RSRPs of the plurality of CSI-RS resources or resource sets.

[0091] In some embodiments, the at least one condition is associated with a configurable quantization range such that the invalidity of calibration measurement is associated with a calibration measurement out of the configurable quantization range. In some embodiments, the configurable quantization range is associated with a cyclic prefix length.

[0092] In some embodiments, the terminal device may select a CSI-RS resource or resource set with a target calibration measurement among the calibration measurements that are not invalid as a reference CSI-RS resource or resource set. In some embodiments, the target calibration measurement is a smallest calibration measurement.

[0093] In some embodiments, the at least one condition is associated with a configurable RSRP threshold with respect to a RSRP of a reference CSI resource or resource set selected from the plurality of CSI-RS resources or resource sets. In some embodiments, the terminal device may select the reference CSI resource or resource set having a target RSRP; and determine that the calibration measurement of a respective CSI-RS resource or resource set is invalid based on determining that the RSRP of the respective CSI-RS resource or resource set is smaller than a difference between the target RSRP of the reference CSI resource or resource set and the RSRP threshold. In some embodiments, the target RSRP is the largest RSRP among RSRPs of the plurality of CSI-RS resources or resource sets.

[0094] In some embodiments, the measured calibration measurement comprises a frequency offset, a phase offset or a delay offset, and the calibration measurement reported in the CSI report indicates a frequency offset difference, a phase offset difference or a delay offset difference between a specific CSI- RS resource or resource set among the plurality of CSI-RS resources or resource sets and a reference CSI-RS resource or resource set selected from the plurality of CSI-RS resources or resource sets. In some embodiments, an invalid state of a specific calibration measurement is indicated by a codepoint of quantization indices of the calibration measurements. In some embodiments, the CSI report comprises at least one reported valid calibration measurement and at least one invalid state indication. In some embodiments, the number of the plurality of CSI-RS resources or resource sets is N, and the total number of reported calibration measurements comprising at least one valid calibration measurement and at least one invalid state indication corresponds to N-1 . In some embodiments, the calibration measurements are associated with a terminal device-assisted coherent joint transmission (CJT) calibration to at least one CSI-RS resource or resource set.

[0095] Fig. 7 illustrates a flowchart of an example method 700 implemented at a network device in accordance with some other embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the network device 120, 130, or 140 with reference to Fig. 1 .

[0096] At block 710, the network device determines a CSI report configuration associated with a plurality of CSI-RS resources or resource sets, the CSI report configuration comprising at least one condition for a terminal device to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid. At block 720, the network device transmits, to the terminal device, the CSI report configuration. At block 730, the network device receives from the terminal device, the CSI report associated with the calibration measurements.

[0097] In some embodiments, the network device may further apply, based on the CSI report, calibration to the CSI-RS resource or resource set for which the calibration measurement thereof is not invalid. In some embodiments, the network device may further configure the plurality of CSI-RS resources or resource sets for the terminal device; receive, from the terminal device, reference signal received powers (RSRPs) for the plurality of CSI-RS resources or resource sets; and configure a RSRP threshold based on the RSRPs of the plurality of CSI-RS resources or resource sets.

[0098] In some embodiments, the at least one condition is associated with the RSRP threshold with respect to a target RSRP among RSRPs of the plurality of CSI-RS resources or resource sets. In some embodiments, the target RSRP is the largest RSRP.

[0099] In some embodiments, the at least one condition is associated with the RSRP threshold with respect to a RSRP of a reference CSI resource or resource set selected from the plurality of CSI-RS resources or resource sets. In some embodiments, the RSRP of the reference CSI resource or resource set selected is the largest RSRP.

[00100] In some embodiments, the network device may further configure the plurality of CSI-RS resources or resource sets for the terminal device; receive, from the terminal device, delay measurements for the plurality of CSI-RS resources or resource sets; and configure a quantization range based on the delay measurements of the plurality of CSI-RS resources or resource sets, wherein the quantitation range is associated with a cyclic prefix length. In some embodiments, the at least one condition is associated with a configurable quantization range such that the invalidity of calibration measurement is associated with a calibration measurement out of the configurable quantization range.

[00101] In some embodiments, the calibration measurement in the CSI report indicates a frequency offset difference, a phase offset difference or a delay offset difference between a specific CSI-RS resource or resource set among the plurality of CSI-RS resources or resource sets and a reference CSI- RS resource or resource set selected from the plurality of CSI-RS resources or resource sets. In some embodiments, an invalid state of a specific calibration measurement is indicated by a codepoint of quantization indices of the calibration measurements. In some embodiments, the CSI report comprises at least one valid calibration measurement and at least one invalid state indication. In some embodiments, the number of the plurality of CSI-RS resources or resource sets is N, and the total number of reported calibration measurements comprising at least one valid calibration measurement and at least one invalid state indication corresponds to N-1 . In some embodiments, the calibration measurements are associated with a terminal device-assisted coherent joint transmission (CJT) calibration to at least one CSI-RS resource or resource set.

[00102] In some embodiments, an apparatus (for example, the terminal device 110) capable of performing the method 600 may comprise means for performing the respective steps 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.

[00103] In some embodiments, the apparatus comprises: means for receiving, from a network device, a CSI report configuration associated with a plurality of CSI-RS resources or resource sets, the CSI report configuration comprising at least one condition to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; means for determining, based on the CSI report configuration, a CSI report associated with the calibration measurements for the plurality of CSI-RS resources or resource sets; and means for transmitting, to the network device, the CSI report.

[00104] In some embodiments, the apparatus may determine, based on the CSI report configuration the CSI report at least by determining whether a calibration measurement is invalid based on the at least one condition. In some embodiments, the at least one condition is associated with a configurable reference signal received power (RSRP) threshold with respect to a target RSRP among RSRPs of the plurality of CSI-RS resources or resource sets. In some embodiments, the apparatus may determine that the calibration measurement of a respective CSI-RS resource or resource set is invalid based on determining that the RSRP of the respective CSI-RS resource or resource set is smaller than a difference between the target RSRP and the RSRP threshold. In some embodiments, the target RSRP is the largest RSRP among RSRPs of the plurality of CSI-RS resources or resource sets.

[00105] In some embodiments, the at least one condition is associated with a configurable quantization range such that the invalidity of calibration measurement is associated with a calibration measurement out of the configurable quantization range. In some embodiments, the configurable quantization range is associated with a cyclic prefix length.

[00106] In some embodiments, the apparatus may select a CSI-RS resource or resource set with a target calibration measurement among the calibration measurements that are not invalid as a reference CSI-RS resource or resource set. In some embodiments, the target calibration measurement is a smallest calibration measurement.

[00107] In some embodiments, the at least one condition is associated with a configurable RSRP threshold with respect to a RSRP of a reference CSI resource or resource set selected from the plurality of CSI-RS resources or resource sets. In some embodiments, the apparatus may select the reference CSI resource or resource set having a target RSRP; and determine that the calibration measurement of a respective CSI-RS resource or resource set is invalid based on determining that the RSRP of the respective CSI-RS resource or resource set is smaller than a difference between the target RSRP of the reference CSI resource or resource set and the RSRP threshold. In some embodiments, the target RSRP is the largest RSRP among RSRPs of the plurality of CSI-RS resources or resource sets.

[00108] In some embodiments, the measured calibration measurement comprises a frequency offset, a phase offset or a delay offset, and the calibration measurement reported in the CSI report indicates a frequency offset difference, a phase offset difference or a delay offset difference between a specific CSI- RS resource or resource set among the plurality of CSI-RS resources or resource sets and a reference CSI-RS resource or resource set selected from the plurality of CSI-RS resources or resource sets. In some embodiments, an invalid state of a specific calibration measurement is indicated by a codepoint of quantization indices of the calibration measurements. In some embodiments, the CSI report comprises at least one reported valid calibration measurement and at least one invalid state indication. In some embodiments, the number of the plurality of CSI-RS resources or resource sets is N, and the total number of reported calibration measurements comprising at least one valid calibration measurement and at least one invalid state indication corresponds to N-1 . In some embodiments, the calibration measurements are associated with a terminal device-assisted coherent joint transmission (CJT) calibration to at least one CSI-RS resource or resource set

[00109] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 600. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[00110] In some embodiments, an apparatus (for example, the network device 120, 130, or 140) capable of performing the method 700 may comprise means for performing the respective steps of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[00111] In some embodiments, the apparatus comprises means for determining a CSI report configuration associated with a plurality of CSI-RS resources or resource sets, the CSI report configuration comprising at least one condition for a terminal device to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; means for transmitting, to the terminal device, the CSI report configuration; and means for receiving from the terminal device, the CSI report associated with the calibration measurements.

[00112] In some embodiments, the apparatus may further apply, based on the CSI report, calibration to the CSI-RS resource or resource set for which the calibration measurement thereof is not invalid. In some embodiments, the apparatus may further configure the plurality of CSI-RS resources or resource sets for the terminal device; receive, from the terminal device, reference signal received powers (RSRPs) for the plurality of CSI-RS resources or resource sets; and configure a RSRP threshold based on the RSRPs of the plurality of CSI-RS resources or resource sets.

[00113] In some embodiments, the at least one condition is associated with the RSRP threshold with respect to a target RSRP among RSRPs of the plurality of CSI-RS resources or resource sets. In some embodiments, the target RSRP is the largest RSRP.

[00114] In some embodiments, the at least one condition is associated with the RSRP threshold with respect to a RSRP of a reference CSI resource or resource set selected from the plurality of CSI-RS resources or resource sets. In some embodiments, the RSRP of the reference CSI resource or resource set selected is the largest RSRP.

[00115] In some embodiments, the apparatus may further configure the plurality of CSI-RS resources or resource sets for the terminal device; receive, from the terminal device, delay measurements for the plurality of CSI-RS resources or resource sets; and configure a quantization range based on the delay measurements of the plurality of CSI-RS resources or resource sets, wherein the quantitation range is associated with a cyclic prefix length. In some embodiments, the at least one condition is associated with a configurable quantization range such that the invalidity of calibration measurement is associated with a calibration measurement out of the configurable quantization range.

[00116] In some embodiments, the calibration measurement in the CSI report indicates a frequency offset difference, a phase offset difference or a delay offset difference between a specific CSI-RS resource or resource set among the plurality of CSI-RS resources or resource sets and a reference CSI- RS resource or resource set selected from the plurality of CSI-RS resources or resource sets. In some embodiments, an invalid state of a specific calibration measurement is indicated by a codepoint of quantization indices of the calibration measurements. In some embodiments, the CSI report comprises at least one valid calibration measurement and at least one invalid state indication. In some embodiments, the number of the plurality of CSI-RS resources or resource sets is N, and the total number of reported calibration measurements comprising at least one valid calibration measurement and at least one invalid state indication corresponds to N-1 . In some embodiments, the calibration measurements are associated with a terminal device-assisted coherent joint transmission (CJT) calibration to at least one CSI-RS resource or resource set.

[00117] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 700. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[00118] Fig. 8 is a simplified block diagram of a device 800 that is suitable for implementing embodiments of the present disclosure. The device 800 may be provided to implement the communication device, for example the terminal device 110, the network device 120, 130 or 140, as shown in Fig. 1 . As shown, the device 800 includes one or more processors 810, one or more memories 820 coupled to the processor 810, and one or more communication modules 840 coupled to the processor 810.

[00119] The communication module 840 is for bidirectional communications. The communication module 840 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network devices.

[00120] The processor 810 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 nonlimiting examples. The device 800 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.

[00121] The memory 820 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) 824, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 822 and other volatile memories that may not last in the power-down duration.

[00122] A computer program 830 includes computer executable instructions that are executed by the associated processor 810. The program 830 may be stored in the ROM 824. The processor 810 may perform any suitable actions and processing by loading the program 830 into the RAM 822.

[00123] The embodiments of the present disclosure may be implemented by means of the program so that the device 800 may perform any process of the disclosure as discussed with reference to Figs. 2, 5, 6, and 7. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[00124] In some embodiments, the program 830 may be tangibly contained in a computer readable medium which may be included in the device 800 (such as in the memory 820) or other storage devices that are accessible by the device 800. The device 800 may load the program 830 from the computer readable medium to the RAM 822 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like.

[00125] Fig. 9 illustrates an example of the computer readable medium 900 in form of CD or DVD in accordance with some embodiments of the present disclosure. The computer readable medium has the program 830 stored thereon. It is noted that although the computer-readable medium 900 is depicted in form of CD or DVD, the computer-readable medium 900 may be in any other form suitable for carry or hold the program 830.

[00126] 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, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[00127] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 600 or 700 as described above with reference to Fig. 6 to Fig. 7. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media. [00128] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes 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 codes, 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.

[00129] In the context of the present disclosure, the computer program codes 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.

[00130] 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. 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).

[00131] Further, while 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, while 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. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that may be described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination. [00132] 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 may be disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:

1 . A terminal device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, from a network device, a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; determine, based on the CSI report configuration, a CSI report associated with the calibration measurements for the plurality of CSI-RS resources or resource sets; and transmit, to the network device, the CSI report.

2. The terminal device of claim 1, wherein the terminal device is caused to determine, based on the CSI report configuration the CSI report at least by: determining whether a calibration measurement is invalid based on the at least one condition.

3. The terminal device of claim 1 or 2, wherein the at least one condition is associated with a configurable reference signal received power (RSRP) threshold with respect to a target RSRP among RSRPs of the plurality of CSI-RS resources or resource sets.

4. The terminal device of claim 3, wherein the terminal device is further caused to: determine that the calibration measurement of a respective CSI-RS resource or resource set is invalid based on determining that the RSRP of the respective CSI-RS resource or resource set is smaller than a difference between the target RSRP and the RSRP threshold.

5. The terminal device of claim 1 or 2, wherein the at least one condition is associated with a configurable quantization range such that the invalidity of calibration measurement is associated with a calibration measurement out of the configurable quantization range.

6. The terminal device of any of claims 2 to 5, wherein the terminal device is further caused to: select a CSI-RS resource or resource set with a target calibration measurement among the calibration measurements that are not invalid as a reference CSI-RS resource or resource set.

7. The terminal device of claim 1 or 2, wherein the at least one condition is associated with a configurable RSRP threshold with respect to a RSRP of a reference CSI resource or resource set selected from the plurality of CSI-RS resources or resource sets.

8. The terminal device of claim 7, wherein the terminal device is further caused to: select the reference CSI resource or resource set having a target RSRP; and determine that the calibration measurement of a respective CSI-RS resource or resource set is invalid based on determining that the RSRP of the respective CSI-RS resource or resource set is smaller than a difference between the target RSRP of the reference CSI resource or resource set and the RSRP threshold.

9. The terminal device of any of claims 1 to 8, wherein the calibration measurement reported in the CSI report indicates a frequency offset difference, a phase offset difference or a delay offset difference between a specific CSI-RS resource or resource set among the plurality of CSI-RS resources or resource sets and a reference CSI-RS resource or resource set selected from the plurality of CSI-RS resources or resource sets.

10. The terminal device of claims 1 to 9, wherein an invalid state of a specific calibration measurement is indicated by a codepoint of quantization indices of the calibration measurements.

11 . The terminal device of claims 1 to 10, wherein the number of the plurality of CSI-RS resources or resource sets is N, and the total number of reported calibration measurements comprising at least one valid calibration measurement and at least one invalid state indication corresponds to N-1.

12. The terminal device of any of claim 1 to 11, wherein the calibration measurements are associated with a terminal device-assisted coherent joint transmission (CJT) calibration to at least one CSI-RS resource or resource set.

13. A network device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: determine a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition for a terminal device to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; transmit, to the terminal device, the CSI report configuration; and receive, from the terminal device, the CSI report associated with the calibration measurements.

14. The network device of claim 13, wherein the network device is further caused to: apply, based on the CSI report, calibration to the CSI-RS resource or resource set for which the calibration measurement thereof is not invalid.

15. The network device of claim 13 or 14, wherein the network device is further caused to: configure the plurality of CSI-RS resources or resource sets for the terminal device; receive, from the terminal device, reference signal received powers (RSRPs) for the plurality of CSI-RS resources or resource sets; and configure a RSRP threshold based on the RSRPs of the plurality of CSI-RS resources or resource sets.

16. The network device of claim 15, wherein the at least one condition is associated with the RSRP threshold with respect to a target RSRP among RSRPs of the plurality of CSI-RS resources or resource sets.

17. The network device of claim 15, wherein the at least one condition is associated with the RSRP threshold with respect to a RSRP of a reference CSI resource or resource set selected from the plurality of CSI-RS resources or resource sets.

18. The network device of claim 13 or 14, wherein the network device is further caused to: configure the plurality of CSI-RS resources or resource sets for the terminal device; receive, from the terminal device, delay measurements for the plurality of CSI-RS resources or resource sets; and configure a quantization range based on the delay measurements of the plurality of CSI-RS resources or resource sets, wherein the quantitation range is associated with a cyclic prefix length.

19. The network device of claim 18, wherein the at least one condition is associated with a configurable quantization range such that the invalidity of calibration measurement is associated with a calibration measurement out of the configurable quantization range.

20. The network device of any of claims 13 to 19, wherein the calibration measurement in the CSI report indicates a frequency offset difference, a phase offset difference or a delay offset difference between a specific CSI-RS resource or resource set among the plurality of CSI-RS resources or resource sets and a reference CSI-RS resource or resource set selected from the plurality of CSI-RS resources or resource sets.

21 . The network device of any of claims 13 to 20, wherein an invalid state of a specific calibration measurement is indicated by a codepoint of quantization indices of the calibration measurements.

22. The network device of any of claim 13 to 21, wherein the calibration measurements are associated with a terminal device-assisted coherent joint transmission (CJT) calibration to at least one CSI-RS resource or resource set.

23. A method implemented at a terminal device, comprising: receiving, from a network device, a channel state information (CSI) report configuration associated with a plurality of CSI reference signal (CSI-RS) resources or resource sets, the CSI report configuration comprising at least one condition to determine whether a calibration measurement for a CSI-RS resource or resource set to be reported by the terminal device is invalid; determining, based on the CSI report configuration, a CSI report associated with the calibration measurements for the plurality of CSI-RS resources or resource sets; and transmitting, to the network device, the CSI report.