CSI-RS configuration

Abstract

Example embodiments of the present disclosure provide solutions for providing channel state information reference signal (CSI-RS) configurations. In an example method, a terminal device receives, at a channel state information reference signal (CSI-RS) instance, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs. The terminal device acquires an effective downlink channel based on the precoded CSI-RS. The terminal device acquires an actual downlink channel based on the channel measurement CSI-RS.

Description

CSI-RS CONFIGURATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority from, and the benefit of, EP Patent Application No. 25166978.4, filed March 28, 2025, the contents 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 a computer readable medium for providing channel state information reference signal (CSI-RS) configuration.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 accordance with standards, such as those promulgated by 3GPP (Third Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). Examples of such standards include the so-called 5G (5th Generation) standard or other standards promulgated by 3GPP.SUMMARY

[0005] In general, example embodiments of the present disclosure provide a solution for providing one or more CSI-RS configurations, for example, for performance monitoring in artificial intelligence (AI) / machine learning (ML)-enabled CSI compression.

[0006] In a first aspect, there is provided a terminal device. The terminal 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, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS, acquire an effective downlink channel based on the precoded CSI-RS, and acquire an actual downlink channel based on the channel measurement CSI-RS. In this document, CSI-RS instance is defined as a slot at which CSI-RS transmission is scheduled by a network device towards a certain terminal device with corresponding configurations of the frequency and time resources and associated code division multiplexing (CDM) type together with the assigned code indices, if applicable.

[0007] In a second aspect, there is provided a network device. The network device comprises at least oneprocessor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: transmit, at a channel state information reference signal (CSI-RS) instance and to a terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS.

[0008] In a third aspect, there is provided a method. The method comprises: receiving, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS, acquiring an effective downlink channel based on the precoded CSI-RS, and acquiring an actual downlink channel based on the channel measurement CSI-RS.

[0009] In a fourth aspect, there is provided a method. The method comprises: transmitting, at a channel state information reference signal (CSI-RS) instance and to a terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS.

[0010] In a fifth aspect, there is provided an apparatus. The apparatus comprises: means for receiving, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS, means for acquiring an effective downlink channel based on the precoded CSI-RS, and means for acquiring an actual downlink channel based on the channel measurement CSI-RS.

[0011] In a sixth aspect, there is provided an apparatus. The apparatus comprises: means for transmitting, at a channel state information reference signal (CSI-RS) instance and to a terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS.

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

[0014] In a ninth aspect, there is provided a terminal device. The terminal device comprises: receiving circuitry configured to receive, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS, first acquiring circuitry configured to acquire an effective downlink channel based on the precoded CSI-RS, and second acquiring circuitry configured to acquire an actual downlink channel based on the channel measurement CSI-RS

[0015] In a tenth aspect, there is provided a network device. The network device comprises: transmitting circuitry configured to transmit, at a channel state information reference signal (CSI-RS) instance and to a terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS.

[0016] In an eleventh aspect, there is provided a first terminal device. The first terminal device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the first terminal device at least to: receive, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs, acquire an effective downlink channel based on the precoded CSI-RS, and acquire an actual downlink channel based on the channel measurement CSI-RS.

[0017] In a twelfth aspect, there is provided a network device. The network device comprises 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: transmit, at a channel state information reference signal (CSI-RS) instance and to a first terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code isapplied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs.

[0018] In a thirteenth aspect, there is provided a method. The method comprises: receiving, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for a first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs, acquiring an effective downlink channel based on the precoded CSI-RS, and acquiring an actual downlink channel based on the channel measurement CSI-RS.

[0019] In a fourteenth aspect, there is provided a method. The method comprises: transmitting, at a channel state information reference signal (CSI-RS) instance and to a first terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs.

[0020] In a fifteenth aspect, there is provided an apparatus. The apparatus comprises: means for receiving, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for a first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs, means for acquiring an effective downlink channel based on the precoded CSI-RS, and means for acquiring an actual downlink channel based on the channel measurement CSI-RS.

[0021] In a sixteenth aspect, there is provided an apparatus. The apparatus comprises: means for transmitting, at a channel state information reference signal (CSI-RS) instance and to a first terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is forchannel measurement CSI-RSs.

[0022] In a seventeenth aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus to perform at least method of the above thirteenth aspect or fourteenth aspect.

[0023] In an eighteenth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform at least the method of the above thirteenth aspect or fourteenth aspect.

[0024] In a nineteenth aspect, there is provided a first terminal device. The first terminal device comprises: receiving circuitry configured to receive, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for a first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs, first acquiring circuitry configured to acquire an effective downlink channel based on the precoded CSI-RS, and second acquiring circuitry configured to acquire an actual downlink channel based on the channel measurement CSI-RS.

[0025] In a twenty aspect, there is provided a network device. The network device comprises: transmitting circuitry configured to transmit, at a channel state information reference signal (CSI-RS) instance and to a first terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs

[0026] In a twenty-first aspect, there is provided a first terminal device. The first terminal device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the first terminal device at least to: receive, from a network device, a triggering signal for triggering a mode switch, and based on receiving the triggering signal, switch from one of a first mode and a second mode to the other one of the first mode and the second mode, in the first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for the first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in the second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for precoded CSI-RSs for a second terminal device and thesecond shared CDM code is also for channel measurement CSI-RSs for the second terminal device.

[0027] In a twenty-second aspect, there is provided a network device. The network device comprises 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: transmit, to a first terminal device, a triggering signal for triggering a mode switch, in a first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for the first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in a second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for the precoded CSI-RSs for a second terminal device and the second shared CDM code is also for the channel measurement CSI-RSs for the second terminal device.

[0028] In a twenty-third aspect, there is provided a method. The method comprises: receiving, from a network device, a triggering signal for triggering a mode switch, and based on receiving the triggering signal, switching from one of a first mode and a second mode to the other one of the first mode and the second mode, in the first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for a first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in the second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for precoded CSI-RSs for a second terminal device and the second shared CDM code is also for channel measurement CSI-RSs for the second terminal device.

[0029] In a twenty-fourth aspect, there is provided a method. The method comprises: transmitting, to a first terminal device, a triggering signal for triggering a mode switch, in a first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for a first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in a second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for the precoded CSI-RSs for a second terminal device and the second shared CDM code is also for the channel measurement CSI-RSs for the second terminal device.

[0030] In a twenty-fifth aspect, there is provided an apparatus. The apparatus comprises: means for receiving, from a network device, a triggering signal for triggering a mode switch, and means for, based on receiving the triggering signal, switching from one of a first mode and a second mode to the other one of the first mode and the second mode, in the first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for a first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in the second mode, a first shared CDM codeis applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for precoded CSI-RSs for a second terminal device and the second shared CDM code is also for channel measurement CSI-RSs for the second terminal device.

[0031] In a twenty-sixth aspect, there is provided an apparatus. The apparatus comprises: means for transmitting, to a first terminal device, a triggering signal for triggering a mode switch, in a first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for a first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in a second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for the precoded CSI-RSs for a second terminal device and the second shared CDM code is also for the channel measurement CSI-RSs for the second terminal device.

[0032] In a twenty-seventh aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus to perform at least method of the above twenty-third aspect or twenty-fourth aspect.

[0033] In a twenty-eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform at least the method of the above twenty-third aspect or twenty-fourth aspect.

[0034] In a twenty-ninth aspect, there is provided a first terminal device. The first terminal device comprises: receiving circuitry configured to receive, from a network device, a triggering signal for triggering a mode switch, and switching circuitry configured to, based on receiving the triggering signal, switch from one of a first mode and a second mode to the other one of the first mode and the second mode, in the first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for a first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in the second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for precoded CSI-RSs for a second terminal device and the second shared CDM code is also for channel measurement CSI-RSs for the second terminal device.

[0035] In a thirtieth aspect, there is provided a network device. The network device comprises: transmitting circuitry configured to transmit, to a first terminal device, a triggering signal for triggering a mode switch, in a first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for a first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in a second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs forthe first terminal device, and the first shared CDM code is also for the precoded CSI-RSs for a second terminal device and the second shared CDM code is also for the channel measurement CSI-RSs for the second terminal device

[0036] 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

[0037] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0038] FIG. 1 A illustrates an example network environment in which some embodiments of the present disclosure can be implemented;

[0039] FIG. 1B illustrates an example UE-network (NW) procedure for precoded RS based UE-side monitoring scheme;

[0040] FIG. 2 illustrates an example of a process flow in accordance with some example embodiments of the present disclosure;

[0041] FIG. 3 illustrates another example of a process flow in accordance with some example embodiments of the present disclosure;

[0042] FIG. 4 illustrates a further example of a process flow in accordance with some example embodiments of the present disclosure;

[0043] FIG. 5 illustrates an example concurrent precoded CSI-RS / normal channel measurement CSI-RS transmission for precoded RS based UE-side monitoring scheme in accordance with some example embodiments of the present disclosure;

[0044] FIG. 6 illustrates an example CDM code collision-free CSI-RS instance sequence patterns for shared CDM code case in accordance with some example embodiments of the present disclosure;

[0045] FIG. 7 illustrates an example locations of CSI-RS in accordance with some example embodiments of the present disclosure;

[0046] FIG. 8A illustrates a CSI-RS instance sequence pattern example for dedicated CDM code case in accordance with some example embodiments of the present disclosure;

[0047] FIG. 8B illustrates a CSI-RS instance sequence pattern example for shared CDM code case in accordance with some example embodiments of the present disclosure;

[0048] FIG. 9A illustrates sequence diagram examples in accordance with some example embodiments of the present disclosure;

[0049] FIG. 9B illustrates sequence diagram examples for shared CDM code mode in accordance withsome example embodiments of the present disclosure;

[0050] FIG. 10 illustrates an example message exchange diagram for performance monitoring in AI / ML-enabled CSI compression use case in accordance with some example embodiments of the present disclosure;

[0051] FIG. 11 illustrates an example message exchange diagram for performance monitoring switching from dedicated CDM code mode to shared CDM code mode in accordance with some example embodiments of the present disclosure;

[0052] FIG. 12 illustrates a flowchart of an example method implemented at a terminal device in accordance with some other embodiments of the present disclosure;

[0053] FIG. 13 illustrates a flowchart of an example method implemented at a network device in accordance with some other embodiments of the present disclosure;

[0054] FIG. 14 illustrates a flowchart of another example method implemented at a first terminal device in accordance with some other embodiments of the present disclosure;

[0055] FIG. 15 illustrates a flowchart of another example method implemented at a network device in accordance with some other embodiments of the present disclosure;

[0056] FIG. 16 illustrates a flowchart of a further example method implemented at a first terminal device in accordance with some other embodiments of the present disclosure;

[0057] FIG. 17 illustrates a flowchart of a further example method implemented at a network device in accordance with some other embodiments of the present disclosure;

[0058] FIG. 18 illustrates a simplified block diagram of a device that is suitable for implementing some example embodiments of the present disclosure; and

[0059] FIG. 19 illustrates a block diagram of an example of a computer-readable medium in accordance with some example embodiments of the present disclosure.

[0060] Throughout the drawings, the same or similar reference numerals represent the same or similar elements.DETAILED DESCRIPTION

[0061] 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 can be implemented in various manners other than the ones described below.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0066] 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 (for example, firmware) for operation, but the software may not be present when it is not needed for operation.

[0067] 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 merelya 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.

[0068] As used herein, the term “network”, “communication network” or “data 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-IoT), wireless fidelity (Wi-Fi) and so on. Furthermore, the communications between a terminal device and a network device / element in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the fourth generation (4G), 4.5G, the future fifth generation (5G), IEEE 802.11 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.

[0069] As used herein, the term “network device” refers to a node in a communication network via which a terminal device receives services (e.g., positioning services) therefrom. The network device may refer to a core network device or access network device, such as base station (BS) or an access point (AP) or a transmission and reception point (TRP), 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 WiFi device, a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology. In the following description, the terms “network device”, “AP device”, “AP” and “access point” may be used interchangeably.

[0070] 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), a station (STA) or station device, or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (for example, remotesurgery), an industrial device and applications (for example, 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 “station”, “station device”, “STA”, “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0071] Principles and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Communications in the communication system may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0072] FIG. 1A 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, comprises terminal devices and network devices.

[0073] As illustrated in FIG. 1A, the communication network may comprise a network device 110 (hereinafter may also be referred to as gNB or NW), and the communication network may further comprise a terminal device 120 (hereinafter may also be referred to as a user equipment or a UE). The network device 110 may manage a cell 101. The terminal device 120 and the network device 110 may communicate data and control information to each other in the coverage of the cell. A link from the network device 110 to the terminal device 120 is referred to as a downlink (DL), while a link from the terminal device 120 to the network device 110 is referred to as an uplink (UL).

[0074] It is to be understood that the number of network devices and terminal devices is only for the purpose of illustration without suggesting any limitations. The communication network may include any suitable number of network devices and terminal devices adapted for implementing embodiments of the present disclosure. Although not shown, it would be appreciated that one or more terminal devices may be located in the environment 100.

[0075] Generally, for AI / ML based CSI compression using two-sided model, one of the major topics is performance monitoring aspect., and FIG. 1B illustrates an example UE-network (NW) procedure for precoded RS based UE-side monitoring scheme. When generating test dataset including K test samples, foreach of the K test samples, a bias factor of monitored intermediate KPI (KPIDiffis calculated as a function of KPIDiff= f ( KPIActual, KPIGenie), where KPIActualis the actual intermediate KPI, and KPIGenieis the genie-aided intermediate KPI.

[0076] As illustrated in FIG. 1 B, UE may only observe an effective downlink channel which has been filtered by precoding (via the reconstructed target CSI, v) as a whole, i.e., _HActualv̂), when all RSs at step 3 are dedicated to the precoded RS. It may be reasonable as long as UE does not need to acquire the individual channel matrix when precoded RS is transmitted (HActual) and / or reconstructed target CSI (v) in a separate manner. For example, KPIActual= \\HActuali>||2of the first alternative / the third alternative or KPIActual= ||HGeniev||2- \\HActuali>||2of the second alternative may be directly acquired by taking a norm of the effective channel without having to derive its individual component (HActualor v).

[0077] However, it is not necessarily the case for other metrics.

[0078] KPIGenie= \\HActualv||2of the first alternative requires UE of knowledge of HActual.

[0079] KPIGenie= ||HGeniev||2- ||HGeniei>||2of the second alternative requires UE of knowledge of v.

[0080] KPIReference= \\HActualvcb\\2ofthe third alternative requires UE of knowledge of HActual.

[0081] In short, in order to facilitate computation of KPIGenie(for the first alternative, the second alternative) or KPIReference(for the third alternative) at UE, gNB is required to transmit normal CSI-RS for channel measurements as well as precoded CSI-RS at step 3 in FIG. 1B.

[0082] It should be noted that once UE acquires HActualvia normal CSI-RS and overall effective channel heff= (HActuaiV) via precoded CSI-RS at step 3, then UE may derive a reconstructed target CSI v by applying pseudo inverse of estimate of HActual, i.e., v = HHActualHActual)- HHActual■ heff-

[0083] Therefore, there is a need to find a CSI-RS resource efficient way of CSI-RS allocation scheme or associated configuration mechanism for a certain UE to enable UE-sided performance monitoring option.

[0084] The following solutions are proposed in some embodiments of the present disclosure.

[0085] First, a method of concurrent CSI-RS configuration by assigning orthogonal CDM codes to channel measurement CSI-RS and to precoded CSI-RS for performance monitoring of two-sided model is proposed. In one embodiment, the network (NW) may assign dedicated CDM codes for channel measurement CSI-RS and precoded CSI-RS for a certain UE.

[0086] In another embodiment, NW may group two UEs (to form “paired companion UEs”) to share two CDM codes between them (i.e., a shared CDM code mode), where one UE may use a certain CDM code for primary CSI-RS for channel measurement and use another CDM code for secondary CSI-RS for precoded RS transmission, and the other UE’s CDM code assignment may be vice versa.

[0087] Second, in the context of shared CDM code mode operation, a method to identify CDM codecollision-free CSI-RS resource sequence patterns for paired UEs, which satisfy the following conditions, is proposed. That is, the length of the CSI-RS sequences for the paired companion UEs sharing CDM codes may be equal, both CSI-RS sequences may contain one skipped CSI-RS instance, the concurrent precoded / channel measurement CSI-RS instance of a certain UE may be synchronized with the skipped CSI-RS instance of its paired companion UE (and vice versa), and / or the preceding channel measurement CSI-RS instance which is used for precoding of CSI-RS may not be forced to skip.

[0088] Third, the signaling procedure, i.e., higher layer signaling (e.g., radio resource control (RRC) configuration) and lower layer signaling (e.g., medium access control control element (MAC CE) or downlink control information (DCI)), and associated parameters are proposed.

[0089] FIG. 2 illustrates an example of a process flow 200 in accordance with some example embodiments of the present disclosure.

[0090] As shown in FIG. 2, at 210, a network device 110 may transmit, at a channel state information reference signal (CSI-RS) instance and to a terminal device 120, a channel measurement CSI-RS and a precoded CSI-RS 212. At the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS 212 are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS.

[0091] Accordingly, at 214, the terminal device 120 may receive, at the CSI-RS instance and from the network device 110, the channel measurement CSI-RS and the precoded CSI-RS 212. Thereafter, at 220, the terminal device 120 may acquire an effective downlink channel based on the precoded CSI-RS, and at 230, the terminal device 120 may acquire an actual downlink channel based on the channel measurement CSI-RS. In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0092] In some embodiments, the terminal device may further transmit, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression. The capability information indicates support of model performance monitoring based on the precoded CSI-RS. Accordingly, in some embodiments, the network device may further receive, from the terminal device, the capability information related to AI / ML enabled CSI compression.

[0093] In some embodiments, the network device may further transmit, to the terminal device, configurations of one or more channel measurement CSI-RS resources, and transmit, to the terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring. The one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0094] Accordingly, in some embodiments, the terminal device may further receive, from the network device, the configurations of one or more channel measurement CSI-RS resources, and receive, from the network device, the configurations of one or more CSI-RS instance sequence patterns for the modelperformance monitoring.

[0095] In some embodiments, the network device may further determine, from the configurations of one or more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0096] Thereafter, in some embodiments, the network device may further transmit, to the terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and the configuration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource. Accordingly, in some embodiments, the terminal device may further receive, from the network device, the indication.

[0097] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0098] FIG. 3 illustrates another example of a process flow 300 in accordance with some example embodiments of the present disclosure.

[0099] As shown in FIG. 3, at 310, a network device 110 may transmit, at a channel state information reference signal (CSI-RS) instance and to a first terminal device 120-1, a channel measurement CSI-RS and a precoded CSI-RS 312. At the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS 312 are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs.

[0100] Accordingly, at 314, the first terminal device 120-1 may receive, at the CSI-RS instance and from the network device 110, the channel measurement CSI-RS and the precoded CSI-RS 312. Thereafter, at 320, the terminal device 120 may acquire an effective downlink channel based on the precoded CSI-RS, and at 330, the terminal device 120 may acquire an actual downlink channel based on the channel measurement CSI-RS. In some embodiments, at the CSI-RS instance, neither precoded CSI-RS nor channel measurement CSI-RS is scheduled for the second terminal device. In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0101] In some embodiments, the first terminal device may further transmit, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression.The capability information indicates support of model performance monitoring based on the precoded CSI-RS. Accordingly, in some embodiments, the network device may further receive, from the first terminal device, the capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression.

[0102] In some embodiments, the network device may further transmit, to the first terminal device, configurations of one or more channel measurement CSI-RS resources, and transmit, to the first terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring. The one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0103] Accordingly, in some embodiments, the first terminal device may further receive, from the network device, the configurations of one or more channel measurement CSI-RS resources, and receive, from the network device, the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring.

[0104] In some embodiments, the network device may further determine, from the configurations of one or more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0105] Thereafter, in some embodiments, the network device may further transmit, to the first terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and the configuration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource. Accordingly, in some embodiments, the first terminal device may further receive, from the network device, the indication.

[0106] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0107] In some embodiments, a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

[0108] FIG. 4 illustrates a further example of a process flow 400 in accordance with some example embodiments of the present disclosure.

[0109] As shown in FIG. 4, at 410, a network device 110 may transmit, to a first terminal device 120-1, a triggering signal 412 for triggering a mode switch. In a first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for the first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in a second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for the precoded CSI-RSs for a second terminal device and the second shared CDM code is also for the channel measurement CSI-RSs for the second terminal device.

[0110] Accordingly, at 414, the first terminal device 120-1 may receive, from the network device 110, the triggering signal 412 for triggering the mode switch. At 420, based on receiving the triggering signal 412, the first terminal device 120-1 may switch from one of the first mode and the second mode to the other one of the first mode and the second mode. In some embodiments, the first dedicated CDM code is orthogonal to the second dedicated CDM code, and the first shared CDM code is orthogonal to the second shared CDM code.

[0111] In some embodiments, the first terminal device may further transmit, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression. The capability information indicates support of model performance monitoring based on the precoded CSI-RS. Accordingly, in some embodiments, the network device may further receive, from the first terminal device, the capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression.

[0112] In some embodiments, the network device may further transmit, to the first terminal device, configurations of one or more channel measurement CSI-RS resources, and transmit, to the first terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring. The one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0113] Accordingly, in some embodiments, the first terminal device may further receive, from the network device, the configurations of one or more channel measurement CSI-RS resources, and receive, from the network device, the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring.

[0114] In some embodiments, the network device may further determine, from the configurations of one or more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0115] Thereafter, in some embodiments, the network device may further transmit, to the first terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and the configuration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource. Accordingly, in some embodiments, the first terminal device may further receive, from the network device, the indication.

[0116] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first dedicated CDM code and the second dedicated CDM code, a type of the first shared CDM code and the second shared CDM code, a first index for the first dedicated CDM code and a second index for the second dedicated CDM code, a third index for the first shared CDM code and a fourth index for the second shared CDM code, or any combination thereof.

[0117] In some embodiments, in the second mode, a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the second CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the second CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

[0118] FIG. 5 illustrates an example concurrent precoded CSI-RS / normal channel measurement CSI-RS transmission for precoded RS based UE-side monitoring scheme in accordance with some example embodiments of the present disclosure, FIG. 6 illustrates an example CDM code collision-free CSI-RS instance sequence patterns for shared CDM code case in accordance with some example embodiments of the present disclosure.

[0119] In addition, FIG. 7 illustrates example locations of CSI-RS in accordance with some example embodiments of the present disclosure, where CSI-RS time frequency locations within a slot are defined. As illustrated in FIG. 7, except for rows 1 and 2, code division multiplexing (CDM) is supported as well, meaning that the same time frequency resources may be shared by UEs for CSI-RS, which may be separated by orthogonal code assignment per configuration of the gNB.

[0120] The present disclosure is to propose assign two orthogonal codes within a CDM group to an UE, i.e., one for normal CSI-RS for channel measurement and the other for precoded CSI-RS, to support concurrent transmission of precoded CSI-RS / channel measurement CSI-RS for performance monitoring. As illustrated in FIG. 5, one advantage is that there may be minimum loss of accuracy of downlink channel estimate (and corresponding derived target CSI (v) calculation) at the occurrence of the precoded CSI-RStransmission, since both the actual downlink propagation channel HActual) and the effective channel at the UE are pertaining to the same time and frequency CSI-RS resources, of which the individual estimates of ^Actual and heffcan be separately acquired at the receiving UE by code division demultiplexing. Another important advantage is that concurrent precoded CSI-RS / channel measurement CSI-RS transmission facilities a seamless CSI acquisition operation. The acquired actual channel using channel measurement CSI-RS at the instance of concurrent CSI-RS transmission slot can be used as an input to CSI encoding and the subsequent CSI feedback can be sent to the NW without any break at the performance monitoring occurrence.

[0121] When it comes to assignment of CDM codes (or their indices) to UEs, the straightforward option is for NW to assign two dedicated CDM codes (one for precoded CSI-RS, the other for channel measurement CSI-RS) to every active UE which supports UE-sided precoded RS based performance monitoring scheme for AI / ML-enabled CSI compression use case. This may allow NW to schedule performance monitoring operation for active UEs without having to coordinate UEs, as the individual UEs are granted with exclusive rights for orthogonal codes for channel measurement CSI-RS and precoded CSI-RS. However, this may not lead to efficient usage of the limited CDM code resources.

[0122] It is expected that performance monitoring may not be triggered so often - not every CSI-RS slot for example. It is therefore anticipated that performance monitoring and the associated concurrent CSI-RS transmission may be configured to take place periodically with a relatively longer period, e.g., every 4 or 6 CSI-RS instances. Then it might be more efficient to let UEs share CDM codes, rather than to allocate dedicated CDM codes. For example (as depicted in FIG. 6), UEO may use codeO as a primary CDM code for channel measurement CSI-RS (which takes place more frequently than precoded CSI-RS) and codel as a secondary CDM code for precoded CSI-RS, whereas its companion UE1 may take a vice versa setting, i.e., codel as a primary CDM code for channel measurement CSI-RS and codeO as a secondary CDM code for precoded CSI-RS. NW transmits a precoded CSI-RS based on UE’s CSI feedback derived from the immediately preceding CSI-RS instance. In this case, it should be noted that NW may skip transmission of any CSI-RS (irrespective of channel measurement CSI-RS or precoded CSI-RS) for a UE, whenever its counterpart companion UE is assigned with concurrent precoded / channel measurement CSI-RSs to avoid any conflict in usage of CDM code for CSI-RS transmission. As can be observed in FIG. 6, there may be a certain pattern, i.e., three CSI-RS instances followed by one CSI-RS-skipped instance for the example of FIG. 6, which satisfies fairness of allocated CSI-RSs between the paired UEs while avoiding CDM code collision between them. This pattern of each UE has a staggered starting point in time with its counterpart companion UE, which requires NW’s coordination. Efficient and fair CDM code assignment requires identification of available patterns for paired UEs and associated offset between them.

[0123] In the present disclosure, notations and assumptions are introduced for the ease of discussions. For the assumptions, CSI-RS for cell measurements for UE is configured by NW via signaling of NZP-CSI-RS-Resource, only CSI-RS scheduled slots are considered as “CSI-RS instances” in the present disclosure, and NW transmits a precoded CSI-RS based on UE’s CSI feedback derived from the immediately preceding CSI-RS instance.

[0124] For the notations in the following figures, ‘0’ refers to skipped CSI-RS instance (no CSI-RS allocation), ‘1’ refers to allocation of CSI-RS for channel measurement only, which is not used for precoding of CSI-RS for next CSI-RS instance. Moreover, ‘1*’ refers to allocation of CSI-RS for channel measurement only, which is used for precoding of CSI-RS for next CSI-RS instance, and ‘2’ refers to concurrent allocation of precoded CSI-RS as well as CSI-RS for channel measurement.

[0125] FIG. 8A illustrates a CSI-RS instance sequence pattern example for dedicated CDM code case in accordance with some example embodiments of the present disclosure, where skipping of CSI-RS instance is not required. Case A in FIG. 8A shows a (rather unlikely) case in which every CSI-RS instance is used for performance monitoring (sequence length: 1; with a pattern: [2]). Case B in FIG. 8A shows a case in which every other CSI-RS instance is used for performance monitoring (sequence length: 2; with a pattern: [1* 2]) for UEO. In this hypothetical example, UE1 cannot be assigned with codeO for performance monitoring purposes (precoded CSI-RS) at all, as codeO is used by UEO at all the CSI-RS instances. For UE1, CDM codel may be used when concurrent CSI-RS transmission does not take place for UEO, i.e., every other CSI-RS instances. It should be noted that for UE1 in FIG. 8A, performance monitoring resource pattern signaling (which will be described below) is not required.

[0126] For the shared CDM code case, the following conditions may need to be satisfied for CDM code collision-free CSI-RS instance sequence pattern. That is, for the desired CSI-RS instance sequence pattern conditions, the length of the CSI-RS sequences for the paired companion UEs sharing CDM codes may be equal, both CSI-RS sequences may contain one skipped CSI-RS instance (one ‘0’), concurrent precoded / channel measurement CSI-RS instance (‘2’) of a certain UE may be synchronized with skipped CSI-RS instance (‘0’) of its paired companion UE (and vice versa), and / or preceding channel measurement CSI-RS instance which is used for precoding of CSI-RS (‘1*’) may not be forced to skip.

[0127] In some examples, CSI-RS instance sequence pattern repeats itself with a periodicity of the sequence length. For convenience, a skipped CSI-RS instance (‘0’) is positioned at the end of sequence, which means that CSI-RS sequence may be in the form of [x x x... x 0].

[0128] FIG. 8B illustrates a CSI-RS instance sequence pattern example for shared CDM code case in accordance with some example embodiments of the present disclosure, which satisfy all of the above-mentioned conditions. Case A is a sequence with the length of 4 (actual CSI-RS allocation: % = 0.75), and Case B is a sequence with the length of 6 (actual CSI-RS allocation: 5 / 6 = 0.83). It should be noted here that for Case A, UEO’s and UE1’s sequence patterns are identical, i.e., [1* 2 1 0], whereas for Case B, they are different, i.e., [1 1 1* 2 1 0] and [1* 2 1 1 1 0]. It can also be observed that the starting points of the sequences may have an offset relative to each other to satisfy the third condition to avoid CDM code collision betweenUEO and UE1.

[0129] Generally, the proposed CDM code assignment and execution of the precoded CSI-RS based performance monitoring procedure may be configured by higher layer signaling (e.g., RRC; a container of the corresponding configuration parameters is named as NZP CSI-RS performance monitoring resource pattern in the present disclosure) and triggered by lower layer signaling (MAC CE or DCI).

[0130] Required parameters for RRC configuration of NZP CSI-RS performance monitoring resource pattern are as follows.

[0131] nzp-CSI-RS-PMResourcePatternld• Index for definition / identification of the container of the configuration parameters.

[0132] nzp-CSI-RS-ResourceldIndex of the associated NZP CSI-RS Resource ID.• Used for identification of the configured CSI-RS allocated slots.

[0133] periodicityAndOffset• Periodicity (equal to the length of the sequence; in CSI-RS instances) and offset (in CSI-RS instances) of the CSI-RS sequence.• Index counting with respect to triggering message (e.g., DCI)-transmitted slot.• Defined similarly as CSI-ResourcePenodicityAndOffset, with a difference of using “CSI-RS instance” rather than “slot” as its unit.• Refer to the flowing Table 1 for possible option of the corresponding RRC parameter definition. Table 1. Example of a possible RRC parameter type definition for Periodicity and Offset of the CSI-RS sequence (unit in CSI-RS instances)C S I - PMRe s o u r ce P a 11 e r n Pe r i od i c i t y An do f f s e t: = CHGICJCSI-RS_candidate_slotsl_dedicatedCdmCode INTEGER (0), CSI-RS_candidate_slots2_dedicatedCdmCode INTEGER (0..1),CSI-RS_candidate_slats3_dedicatedCdmCode INTEGER (0..2 ),CSI-RS candidate slats 4 dedicatedCdmCode INTEGER ( 0.CSI-RS_candidate_slots5_dedicatedCdmCode INTEGER (0..4),CSI-RS_candidate_slots6_dedicatedCdmCode INTEGER (0..5),CSI-RS_candidate_slots7_dedicatedCdmCode INTEGER (0..6),CSI-RS candidate slotso dedicatedCdmCode INTEGER <0..7),CSI-RS candidate s lots4 sharedCdmCode INTEGER (0..3), CSI-RS_candidate_slots6_sharedCdmCode INTEGER (0..5), CSI-RS_candidate_slots7_sharedCdmCode INTEGER (0..6), CSI-RS candidate slots8 sharedCdmCode INTEGER (0..7),

[0134] perfMonitoringRSPosition• Index of the CSI-RS instance at which concurrent precoded / channel measurement CSI-RS is scheduled.• Integer value, starting from 0.• Index counting with respect to the starting point of the sequence.

[0135] cdm-Type• May be defined as optional.• This field may be used to overwrite the corresponding configuration defined in the associated NZP CSI-RS Resource.

[0136] codelndexCM• Index of primary CDM code for channel measurement CSI-RS per configured cdm-Type.

[0137] codelndexPC• Index of secondary CDM code for precoded CSI-RS per configured cdm-Type.

[0138] It should be noted here that the above-described parameter definition may be used irrespective of dedicated or shared CDM code modes.

[0139] For better understanding of the aforementioned parameters, FIG. 9A illustrates sequence diagram examples in accordance with some example embodiments of the present disclosure, and FIG. 9B illustrates sequence diagram examples for shared CDM code mode in accordance with some example embodiments of the present disclosure. The very beginning of each diagram corresponds to the configuration triggering message (e.g., DCI) reception point. The top first and second cases correspond to Case A and Case B in FIG. 8A, respectively. The bottom first case corresponds to Case A in FIG. 8B. For instance, in case of [shared CDM code: sequence length 4 CSI-RS instances] of FIG. 9A, periodicityAndOffset and perfMonitoringRSPosition parameters may be configured as below. It should be noted that in FIGS. 9A and 9B, perfMonitoringRSPosition is denoted by concurrentCSI-RSPosition.

[0140] In [shared CDM code::sequence length 4 CSI-RS instances] of FIG. 9A, for UEO:periodicity. 4, offset. 1perfMonitoringRSPosition-. 1

[0141] In addition, for UE1:periodicity. 4, offset. 3perfMonitoringRSPosition-. 1

[0142] Moreover, as illustrated in FIG. 9B, UEO.offset has been set to 0 for all the cases for brevity without loss of generality. UE1.offset may be taken as a relative offset with respect to UEO.offset. It should be noted that up to the sequence length 8, only the below cases are identified to satisfy the aforementioned “desired CSI-RS instance sequence pattern conditions”. Table 2 below summarizes the identified possible parameter combinations for shared CDM code mode, up to periodicity 8. It should be noted that in Table 2, parameter value pair denoted in (UEO, UE1 ) may have the unit of CSI-RS instance.Table 2. Parameter setting example of NZP CSI-RS performance monitoring resource pattern for shared CDM code modeliiiifiiii iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiM4 perfMonitoringRSPosition (1,1)offset (0,2)6 perfMonitoringRSPosition (1,3) (3,1)Offset (0,2) (0,4) perfMonitoringRSPosition (2,2)offset (0,3)7 perfMonitoringRSPosition (1,4) (4,1)Offset (0,2) (0,5) perfMonitoringRSPosition (2,3) (3,2) offset (0,3) (0,4) 8 perfMonitoringRSPosition (1,5) (5,1)Offset (0,2) (0,6) perfMonitoringRSPosition (2,4) (4,2) offset (0,3) (0,5) perfMonitoringRSPosition (3,3)offset(0,4)

[0143] The contents of Table 2 may be reflected in definition of the corresponding RRC parameter for Periodicity and Offset. See Table 1 for this example. As shown in Table 1, periodicity and offset data type may be categorized into dedicated CDM code mode case and shared CDM code mode case.

[0144] FIG. 10 illustrates an example message exchange diagram for performance monitoring in AI / ML-enabled CSI compression use case in accordance with some example embodiments of the present disclosure.

[0145] At 1001, as a part of UE capability reporting, UE may report AI / ML-enabled CSI compression feature related UE capabilities, including whether it supports for precoded (CSI-)RS based UE-side performance monitoring option.

[0146] At 1002, configurations of possibly multiple candidate CSI-RS performance monitoring resource patterns (which are denoted as “NZP CSI-RS performance monitoring resource pattern" in the present disclosure) are notified by NW to UE, together with their associated NZP CSI-RS Resources (refer to Table 3 for its parameter fields).Table 3. NZP-CSI-RS-Resource IE and its parameter fieldsNZP -CSI -RS- esource SEQUENCE {nzp-CSI-RS-Resourceld NZP- CSI -RS -Resour celd,r soitrce lapping CSIzfiSz e so urceMappin g,powe rCont olOf f s et INTEGER (-8..15),powerCort rolOf f setSS ENUMERATED{db-3, db8, db3, db6} OPTIONAL, -- Need R sc rambling ID Scramblingldjperiod i c i tyAn dOf f s et CSI -Re sour cePer iodi ityAn Off set OPTIONAL, - qcl-Inf oPeriodicCSI-RS TCI-Stateld OPTIOfiAL, -- Cord Periodic

[0147] At 1003, NW determines to initiate precoded (CSI-)RS based UE-side performance monitoring procedure. NW selects one configuration option out of the previously notified configurations with respect to CSI-RS measurement resource with determination of its parameters, i.e., CSI-RS resource ID, CSI-RS resource mapping, power control offset, periodicity and offset in slots, etc., as well as its associated performance monitoring resource sequence pattern with configuration of the relevant parameters, i.e., performance monitoring resource pattern ID, associated CSI-RS resource ID (to provide a link to the resource allocation of the CSI-RS instance), periodicity and offset in CSI-RS instances, index of the CSI-RS instance at which concurrent precoded / channel measurement CSI-RS is scheduled, cdm-Type, two code indices, i.e., one for primary CDM code for channel measurement CSI-RS and the other for secondary CDM code for precoded CSI-RS, respectively.

[0148] At 1004, NW indicates UE of the selected CSI-RS measurement / performance monitoring resource configuration and their configured parameters via lower level signaling, e.g., MAC CE or DCI.

[0149] At 1005 and 1006, normal CSI acquisition operation runs, which follows the following procedure (1005) of CSI-RS transmission for channel measurements, channel estimation / pre-processing followed by AI / ML-assisted target CSI encoding (CSI compression) at UE (omitted in FIG. 10), and (1006) CSI feedback report. NW reconstructs the target CSI by AI / ML-assisted CSI decoding (omitted in FIG. 10).

[0150] In the meantime, performance monitoring is due.

[0151] At 1007, NW transmits CSI-RS for channel measurement. Its corresponding reconstructed target CSI will be used as a precoding for the subsequent CSI-RS at 1011, once UE provides a corresponding encoded target CSI at 1009.

[0152] At 1008, based on the transmitted CSI-RS, UE performs channel estimation / pre-processing followed by AI / ML-assisted target CSI encoding (CSI compression).

[0153] At 1009, UE reports the acquired CSI information.

[0154] At 1010, NW reconstructs the target CSI by AI / ML-assisted CSI decoding. NW takes the reconstructed target CSI and uses it for precoding of the subsequent CSI-RS. NW performs code division multiplexing of precoded CSI-RS (using a secondary CDM code) and channel measurement CSI-RS (using a primary CDM code) by using the configured code indices at 1003.

[0155] At 1011, NW transmits precoded CSI-RS and channel measurement CSI-RS at the same CSI-RS instance, which are scheduled with the same time and frequency CSI-RS resources and separable at UE by applying the assigned primary / secondary CDM code at 1004.

[0156] At 1012, UE acquires the effective channel and the downlink actual channel by using precoded CSI-RS and channel measurement CSI-RS, respectively. Then UE computes KPIs, e.g., KPlActua / , KPIceme, and / or KPlReference, as described above. This KPI or its possible alternatives may be configured by NW in RRC message (for example at 1002).

[0157] At 1013, UE reports the computed KPI(s).

[0158] At 1014 and 1015, UE may perform CSI compression and subsequent reporting of CSI, based on the measured downlink (actual) channel.

[0159] FIG. 11 illustrates an example message exchange diagram for performance monitoring switching from dedicated CDM code mode to shared CDM code mode in accordance with some example embodiments of the present disclosure.

[0160] As the number of active UEs increases, NW may want to take back previously exclusively assigned CDM codes for UEO (one for channel measurement CSI-RS, the other for precoded CSI-RS) and make the paired UEs (UEO and UE1) share these CDM codes. This re-assignment of CDM codes may be triggered by lower level signaling at 1105 and 1106 in FIG. 11. Hence, the CDM code mode switching may be performed with low latency. It should be noted that in this case, when one UE receives concurrent precoded CSI-RS / channel measurement CSI-RS at 1110 and 1114 in FIG. 11, NW is required to skip CSI-RS transmission for the other UE at 1109 and 1113 in FIG. 11.

[0161] As illustrated in FIGS. 10 and 11, 1101 and 1102 in FIG. 11 correspond to 1001 and 1002 in FIG.10, respectively.

[0162] At 1103, it corresponds to 1004 in FIG. 10. In this example of FIG. 11, NW decides to allocate two dedicated CDM codes (code 0 and code 1) to UEO, i.e., one (code 0) for channel measurement CSI-RS, the other (code 1) for precoded CSI-RS. This selection of “dedicated CDM code mode” is signaled to UEO via NW’s configuration of periodicityAndOffset. See Table 1 for exemplary definition of the corresponding RRC parameter definition.

[0163] At 1104, AI / ML-enabled CSI acquisition and performance monitoring operation proceeds. This may be considered as continuous operation, in the sense that there is no gap in operation. This is possible due to dedicated CDM code assignment.

[0164] In the meantime, the number of active UEs increases, so does the demand for CDM codes as regards CSI-RS resource allocation. In order to cope with this situation, NW decides to re-assign CSI-RS CDM codes. This leads UEO to switch from dedicated CDM code mode to shared CDM code mode, and to share its CDM codes (code 0 and code 1) with UE1. NW decides to select one of periodicity of 6 cases (the second from the top in FIG. 9B) in this example.

[0165] At 1105, NW signals UEO of switching to the shared CDM code mode via re-configuration of periodicityAndOffset parameter, e.g., CSI-RS_candidate_slots6_sharedCdmCode with offset of 0 and perfMonitoringRSPosition of 3. CDM code index for the primary CSI-RS is 0, and for the secondary CDM code index is 1.

[0166] At 1106, per the selected paired sequence pattern definition, NW signals UE1 of the shared CDM code mode via configuration of periodicityAndOffset parameter, e.g., CSI-RS_candidate_slots6_sharedCdmCode with offset of 4 and perfMonitoringRSPosition of 1. CDM code index for the primary CSI-RS is 1, and for the secondary CDM code index is 0, which are shared with UEO in acomplementary manner.

[0167] At 1107, AI / ML-enabled CSI acquisition and performance monitoring operation proceeds. This may be characterized as operation with occasional skipping of CSI-RS, which is enforced to prevent CDM code collision between paired UEs, i.e., UEO and UE1.

[0168] As illustrated in FIGS. 10 and 11, 1108 in FIG. 11 is similar with 1005 in FIG. 10, 1111 in FIG. 11 is similar with 1007 in FIG. 10, 1112 in FIG. 11 is similar with 1009 in FIG. 10, 1115 in FIG. 11 is similar with 1013 in FIG. 10, and 1116 in FIG. 11 is similar with 1015 in FIG. 10.

[0169] When one UE receives concurrent precoded CSI-RS / channel measurement CSI-RS at 1110 and 1114, NW is required to skip CSI-RS transmission for the other UE at 1109 and 1113.

[0170] FIG. 12 illustrates a flowchart of an example method 1200 implemented at a terminal device in accordance with some other embodiments of the present disclosure. For ease of understanding, the method 1200 will be described from the perspective of the terminal device 120 with reference to FIG. 2.

[0171] At block 1210, the terminal device may receive, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS. At block 1220, the terminal device may acquire an effective downlink channel based on the precoded CSI-RS. At block 1230, acquire an actual downlink channel based on the channel measurement CSI-RS.

[0172] In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0173] In some embodiments, the terminal device may further transmit, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0174] In some embodiments, the terminal device may further receive, from the network device, configurations of one or more channel measurement CSI-RS resources, and receive, from the network device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0175] In some embodiments, the terminal device may further receive, from the network device, an indication of a determined configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0176] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RSare scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0177] FIG. 13 illustrates a flowchart of an example method 1300 implemented at a network device in accordance with some other embodiments of the present disclosure. For ease of understanding, the method 1300 will be described from the perspective of the network device 110 with reference to FIG. 2.

[0178] At block 1310, the network device may transmit, at a channel state information reference signal (CSI-RS) instance and to a terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS.

[0179] In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0180] In some embodiments, the network device may further receive, from the terminal device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0181] In some embodiments, the network device may further transmit, to the terminal device, configurations of one or more channel measurement CSI-RS resources, and transmit, to the terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0182] In some embodiments, the network device may further determine, from the configurations of one or more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0183] In some embodiments, the network device may further transmit, to the terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and the configuration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0184] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0185] In some embodiments, an apparatus capable of performing any of the method 1200 (for example, the terminal device 120) may comprise means for performing the respective steps of the method 1200. Themeans may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0186] In some embodiments, the apparatus comprises means for receiving, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS; means for acquiring an effective downlink channel based on the precoded CSI-RS; and means for acquiring an actual downlink channel based on the channel measurement CSI-RS.

[0187] In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0188] In some embodiments, the terminal device may further transmit, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0189] In some embodiments, the terminal device further comprises means for receiving, from the network device, configurations of one or more channel measurement CSI-RS resources; and means for receiving, from the network device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0190] In some embodiments, the terminal device further comprises means for receiving, from the network device, an indication of a determined configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0191] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0192] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1200. 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.

[0193] In some embodiments, an apparatus capable of performing any of the method 1300 (for example, the network device 110) may comprise means for performing the respective steps of the method 1300. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitryor software module.

[0194] In some embodiments, the apparatus comprises means for transmitting, at a channel state information reference signal (CSI-RS) instance and to a terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled with the same time and frequency CSI-RS resources, and a first code division multiplexing (CDM) code is applied to the channel measurement CSI-RS and a second CDM code is applied to the precoded CSI-RS.

[0195] In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0196] In some embodiments, the apparatus further comprises means for receiving, from the terminal device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0197] In some embodiments, the apparatus further comprises means for transmitting, to the terminal device, configurations of one or more channel measurement CSI-RS resources; and means for transmitting, to the terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0198] In some embodiments, the apparatus further comprises means for determining, from the configurations of one or more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0199] In some embodiments, the apparatus further comprises means for transmitting, to the terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and the configuration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0200] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0201] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1300. 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 codeconfigured to, with the at least one processor, cause the performance of the apparatus.

[0202] FIG. 14 illustrates a flowchart of an example method 1400 implemented at a first terminal device in accordance with some other embodiments of the present disclosure. For ease of understanding, the method 1400 will be described from the perspective of the first terminal device 120-1 with reference to FIG. 3.

[0203] At block 1410, the first terminal device may receive, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs. At block 1420, the first terminal device may acquire an effective downlink channel based on the precoded CSI-RS. At block 1430, the first terminal device may acquire an actual downlink channel based on the channel measurement CSI-RS.

[0204] In some embodiments, at the CSI-RS instance, neither precoded CSI-RS nor channel measurement CSI-RS is scheduled for the second terminal device.

[0205] In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0206] In some embodiments, the first terminal device may further transmit, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0207] In some embodiments, the first terminal device may further receive, from the network device, configurations of one or more channel measurement CSI-RS resources, and receive, from the network device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0208] In some embodiments, the first terminal device may further receive, from the network device, an indication of a determined configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0209] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0210] In some embodiments, a first length of a first CSI-RS sequence for the first terminal device equalsto a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

[0211] FIG. 15 illustrates a flowchart of an example method 1500 implemented at a network device in accordance with some other embodiments of the present disclosure. For ease of understanding, the method 1500 will be described from the perspective of the network device 110 with reference to FIG. 3.

[0212] At block 1510, the network device may transmit, at a channel state information reference signal (CSI-RS) instance and to a first terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs.

[0213] In some embodiments, at the CSI-RS instance, neither precoded CSI-RS nor channel measurement CSI-RS is scheduled for the second terminal device.

[0214] In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0215] In some embodiments, the network device may further receive, from the first terminal device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0216] In some embodiments, the network device may further transmit, to the first terminal device, configurations of one or more channel measurement CSI-RS resources, and transmit, to the first terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0217] In some embodiments, the network device may further determine, from the configurations of one or more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0218] In some embodiments, the network device may further transmit, to the first terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and theconfiguration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0219] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0220] In some embodiments, a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

[0221] In some embodiments, an apparatus capable of performing any of the method 1400 (for example, the first terminal device 120-1) may comprise means for performing the respective steps of the method 1400. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0222] In some embodiments, the apparatus comprises means for receiving, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs; means for acquiring an effective downlink channel based on the precoded CSI-RS; and means for acquiring an actual downlink channel based on the channel measurement CSI-RS.

[0223] In some embodiments, at the CSI-RS instance, neither precoded CSI-RS nor channel measurement CSI-RS is scheduled for the second terminal device.

[0224] In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0225] In some embodiments, the apparatus further comprises means for transmitting, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0226] In some embodiments, the apparatus further comprises means for receiving, from the network device, configurations of one or more channel measurement CSI-RS resources; and means for receiving, from the network device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0227] In some embodiments, the apparatus further comprises means for receiving, from the network device, an indication of a determined configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0228] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0229] In some embodiments, a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

[0230] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1400. 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.

[0231] In some embodiments, an apparatus capable of performing any of the method 1500 (for example, the network device 110) may comprise means for performing the respective steps of the method 1500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0232] In some embodiments, the apparatus comprises means for transmitting, at a channel state information reference signal (CSI-RS) instance and to a first terminal device, a channel measurement CSI-RS and a precoded CSI-RS, at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurementCSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs.

[0233] In some embodiments, at the CSI-RS instance, neither precoded CSI-RS nor channel measurement CSI-RS is scheduled for the second terminal device.

[0234] In some embodiments, the first CDM code is orthogonal to the second CDM code.

[0235] In some embodiments, the apparatus further comprises means for receiving, from the first terminal device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0236] In some embodiments, the apparatus further comprises means for transmitting, to the first terminal device, configurations of one or more channel measurement CSI-RS resources; and means for transmitting, to the first terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0237] In some embodiments, the apparatus further comprises means for determining, from the configurations of one or more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0238] In some embodiments, the apparatus further comprises means for transmitting, to the first terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and the configuration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0239] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first CDM code and the second CDM code, a first index for the first CDM code and a second index for the second CDM code, or any combination thereof.

[0240] In some embodiments, a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instanceis used for precoding of CSI-RS.

[0241] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1500. 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.

[0242] FIG. 16 illustrates a flowchart of an example method 1600 implemented at a first terminal device in accordance with some other embodiments of the present disclosure. For ease of understanding, the method 1600 will be described from the perspective of the first terminal device 120-1 with reference to FIG. 4.

[0243] At block 1610, the first terminal device may receive, from a network device, a triggering signal for triggering a mode switch. At 1620, the first terminal device may, based on receiving the triggering signal, switch from one of a first mode and a second mode to the other one of the first mode and the second mode, in the first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for the first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in the second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for precoded CSI-RSs for a second terminal device and the second shared CDM code is also for channel measurement CSI-RSs for the second terminal device.

[0244] In some embodiments, the first dedicated CDM code is orthogonal to the second dedicated CDM code, and the first shared CDM code is orthogonal to the second shared CDM code.

[0245] In some embodiments, the first terminal device may further transmit, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0246] In some embodiments, the first terminal device may further receive, from the network device, configurations of one or more channel measurement CSI-RS resources, and receive, from the network device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0247] In some embodiments, the first terminal device may further receive, from the network device, an indication of a determined configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0248] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RSinstances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first dedicated CDM code and the second dedicated CDM code, a type of the first shared CDM code and the second shared CDM code, a first index for the first dedicated CDM code and a second index for the second dedicated CDM code, a third index for the first shared CDM code and a fourth index for the second shared CDM code, or any combination thereof.

[0249] In some embodiments, in the second mode, a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the second CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the second CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

[0250] FIG. 17 illustrates a flowchart of an example method 1700 implemented at a network device in accordance with some other embodiments of the present disclosure. For ease of understanding, the method 1700 will be described from the perspective of the network device 110 with reference to FIG. 4.

[0251] At block 1710, the network device may transmit, to a first terminal device, a triggering signal for triggering a mode switch, in a first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for the first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in a second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for the precoded CSI-RSs for a second terminal device and the second shared CDM code is also for the channel measurement CSI-RSs for the second terminal device.

[0252] In some embodiments, the first dedicated CDM code is orthogonal to the second dedicated CDM code, and the first shared CDM code is orthogonal to the second shared CDM code.

[0253] In some embodiments, the network device may further receive, from the first terminal device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0254] In some embodiments, the network device may further transmit, to the first terminal device, configurations of one or more channel measurement CSI-RS resources, and transmit, to the first terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0255] In some embodiments, the network device may further determine, from the configurations of oneor more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0256] In some embodiments, the network device may further transmit, to the first terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and the configuration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0257] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first dedicated CDM code and the second dedicated CDM code, a type of the first shared CDM code and the second shared CDM code, a first index for the first dedicated CDM code and a second index for the second dedicated CDM code, a third index for the first shared CDM code and a fourth index for the second shared CDM code, or any combination thereof.

[0258] In some embodiments, in the second mode, a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the second CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the second CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

[0259] In some embodiments, an apparatus capable of performing any of the method 1600 (for example, the first terminal device 120-1) may comprise means for performing the respective steps of the method 1600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0260] In some embodiments, the apparatus comprises means for receiving, from a network device, a triggering signal for triggering a mode switch; and means for, based on receiving the triggering signal, switching from one of a first mode and a second mode to the other one of the first mode and the second mode, in the first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for the first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in the second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for precoded CSI-RSsfor a second terminal device and the second shared CDM code is also for channel measurement CSI-RSs for the second terminal device.

[0261] In some embodiments, the first dedicated CDM code is orthogonal to the second dedicated CDM code, and the first shared CDM code is orthogonal to the second shared CDM code.

[0262] In some embodiments, the apparatus further comprises means for transmitting, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0263] In some embodiments, the apparatus further comprises means for receiving, from the network device, configurations of one or more channel measurement CSI-RS resources; and means for receiving, from the network device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0264] In some embodiments, the apparatus further comprises means for receiving, from the network device, an indication of a determined configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0265] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource ID associated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first dedicated CDM code and the second dedicated CDM code, a type of the first shared CDM code and the second shared CDM code, a first index for the first dedicated CDM code and a second index for the second dedicated CDM code, a third index for the first shared CDM code and a fourth index for the second shared CDM code, or any combination thereof.

[0266] In some embodiments, in the second mode, a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the second CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the second CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

[0267] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1600. 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 codeconfigured to, with the at least one processor, cause the performance of the apparatus.

[0268] In some embodiments, an apparatus capable of performing any of the method 1700 (for example, the network device 110) may comprise means for performing the respective steps of the method 1700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0269] In some embodiments, the apparatus comprises means for transmitting, to a first terminal device, a triggering signal for triggering a mode switch, in a first mode, a first dedicated code division multiplexing (CDM) code is applied to channel measurement CSI-RSs for the first terminal device, and a second dedicated CDM code is applied to precoded CSI-RSs for the first terminal device, and in a second mode, a first shared CDM code is applied to the channel measurement CSI-RSs for the first terminal device and a second shared CDM code is applied to the precoded CSI-RSs for the first terminal device, and the first shared CDM code is also for the precoded CSI-RSs for a second terminal device and the second shared CDM code is also for the channel measurement CSI-RSs for the second terminal device.

[0270] In some embodiments, the first dedicated CDM code is orthogonal to the second dedicated CDM code, and the first shared CDM code is orthogonal to the second shared CDM code.

[0271] In some embodiments, the apparatus further comprises means for receiving, from the first terminal device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

[0272] In some embodiments, the apparatus further comprises means for transmitting, to the first terminal device, configurations of one or more channel measurement CSI-RS resources; and means for transmitting, to the first terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

[0273] In some embodiments, the apparatus further comprises means for determining, from the configurations of one or more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0274] In some embodiments, the apparatus further comprises means for transmitting, to the first terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and the configuration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

[0275] In some embodiments, a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises a performance monitoring resource pattern ID, a CSI-RS resource IDassociated with the performance monitoring resource pattern ID, a periodicity and an offset in CSI-RS instances, an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled, a type of the first dedicated CDM code and the second dedicated CDM code, a type of the first shared CDM code and the second shared CDM code, a first index for the first dedicated CDM code and a second index for the second dedicated CDM code, a third index for the first shared CDM code and a fourth index for the second shared CDM code, or any combination thereof.

[0276] In some embodiments, in the second mode, a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device, both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance, the second CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device, a preceding channel measurement CSI-RS instance of the second CSI-RS instance is not skipped, or any combination thereof. The preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

[0277] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1700. 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.

[0278] FIG. 18 illustrates a simplified block diagram of a device 1800 that is suitable for implementing some example embodiments of the present disclosure. The device 1800 may be provided to implement a communication device, for example, the terminal device 120 (or the first terminal device 120-1) or the network device 110 as shown in FIGS. 2-4. As shown, the device 1800 includes one or more processors 1810, one or more memories 1820 coupled to the processor 1810, and one or more communication modules 1840 coupled to the processor 1810.

[0279] The communication module 1840 is for bidirectional communications. The communication module 1840 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

[0280] The processor 1810 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1800 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.

[0281] The memory 1820 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) 1824, 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 thevolatile memories include, but are not limited to, a random access memory (RAM) 1822 and other volatile memories that will not last in the power-down duration.

[0282] A computer program 1830 includes computer executable instructions that are executed by the associated processor 1810. The program 1830 may be stored in the ROM 1824. The processor 1810 may perform any suitable actions and processing by loading the program 1830 into the RAM 1822.

[0283] The embodiments of the present disclosure may be implemented by means of the program 1830 so that the device 1800 may perform any process of the disclosure as discussed with reference to FIGS. 2-4. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0284] In some example embodiments, the program 1830 may be tangibly contained in a computer-readable medium which may be included in the device 1800 (such as in the memory 1820) or other storage devices that are accessible by the device 1800. The device 1800 may load the program 1830 from the computer-readable medium to the RAM 1822 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.

[0285] FIG. 19 illustrates a block diagram of an example of a computer-readable medium 1900 in accordance with some example embodiments of the present disclosure. The computer-readable medium 1900 has the program 1830 stored thereon. It is noted that although the computer-readable medium 1900 is depicted in form of CD or DVD in FIG. 19, the computer-readable medium 1900 may be in any other form suitable for carry or hold the program 1830.

[0286] 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.

[0287] 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 computerexecutable 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 1200 or 1300 or 1400 or 1500 or 1600 or 1700 as described above with reference to FIG. 12 or 13 or 14 or 15 or 16 or 17. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks orimplement 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.

[0288] 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.

[0289] 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.

[0290] 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).

[0291] 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 are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination.

[0292] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:

1. A first terminal device comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the first terminal device at least to:receive, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, wherein at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and wherein:for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI- RSs, andfor a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs;acquire an effective downlink channel based on the precoded CSI-RS; and acquire an actual downlink channel based on the channel measurement CSI-RS.

2. The terminal device of claim 1, wherein at the CSI-RS instance, neither precoded CSI-RS nor channel measurement CSI-RS is scheduled for the second terminal device.

3. The first terminal device of claim 1 or 2, wherein the first CDM code is orthogonal to the second CDM code.

4. The first terminal device of any of claims 1 -3, wherein the first terminal device is further caused to: transmit, to the network device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, wherein the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

5. The first terminal device of claim 4, wherein the first terminal device is further caused to: receive, from the network device, configurations of one or more channel measurement CSI-RS resources; andreceive, from the network device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, wherein the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

6. The first terminal device of claim 5, wherein the first terminal device is further caused to: receive, from the network device, an indication of a determined configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

7. The first terminal device of any of claims 5-6, wherein a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises at least one of the following:a performance monitoring resource pattern ID;a CSI-RS resource ID associated with the performance monitoring resource pattern ID; a periodicity and an offset in CSI-RS instances;an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled;a type of the first CDM code and the second CDM code; ora first index for the first CDM code and a second index for the second CDM code.

8. The first terminal device of claim 7, wherein at least one of the following:a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device;both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance;the CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device; ora preceding channel measurement CSI-RS instance of the CSI-RS instance is not skipped, wherein the preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

9. A network device comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to:transmit, at a channel state information reference signal (CSI-RS) instance and to a first terminal device, a channel measurement CSI-RS and a precoded CSI-RS, wherein at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and wherein:for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI- RSs, andfor a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs.

10. The terminal device of claim 9, wherein at the CSI-RS instance, neither precoded CSI-RS nor channel measurement CSI-RS is scheduled for the second terminal device.

11. The network device of claim 9 or 10, wherein the first CDM code is orthogonal to the second CDM code.

12. The network device of any of claims 9-11, wherein the network device is further caused to: receive, from the first terminal device, capability information related to artificial intelligence (AI) / machine learning (ML) enabled CSI compression, wherein the capability information indicates support of model performance monitoring based on the precoded CSI-RS.

13. The network device of claim 12, wherein the network device is further caused to: transmit, to the first terminal device, configurations of one or more channel measurement CSI-RS resources; andtransmit, to the first terminal device, configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, wherein the one or more CSI-RS instance sequence patterns for the model performance monitoring are associated with the one or more channel measurement CSI-RS resources.

14. The network device of claim 13, wherein the network device is further caused to: determine, from the configurations of one or more channel measurement CSI-RS resources and the configurations of one or more CSI-RS instance sequence patterns for the model performance monitoring, a configuration of a channel measurement CSI-RS resource and a configuration of a CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

15. The network device of claim 14, wherein the network device is further caused to: transmit, to the first terminal device, an indication of the determined configuration of the channel measurement CSI-RS resource and the configuration of the CSI-RS instance sequence pattern associated with the channel measurement CSI-RS resource.

16. The network device of any of claims 13-15, wherein a configuration of the CSI-RS instance sequence pattern for the model performance monitoring comprises at least one of the following:a performance monitoring resource pattern ID;a CSI-RS resource ID associated with the performance monitoring resource pattern ID; a periodicity and an offset in CSI-RS instances;an index of a CSI-RS instance at which a channel measurement CSI-RS and a precoded CSI-RS are scheduled;a type of the first CDM code and the second CDM code; ora first index for the first CDM code and a second index for the second CDM code.

17. The network device of claim 16, wherein at least one of the following:a first length of a first CSI-RS sequence for the first terminal device equals to a second length of a second CSI-RS sequence for the second terminal device;both the first CSI-RS sequence for the first terminal device and the second CSI-RS sequence for the second terminal device include at least one skipped CSI-RS instance;the CSI-RS instance is synchronized with a skipped CSI-RS instance of the second terminal device; ora preceding channel measurement CSI-RS instance of the CSI-RS instance is not skipped, wherein the preceding channel measurement CSI-RS instance is used for precoding of CSI-RS.

18. A method comprising:receiving, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, wherein at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for a first terminal device with the same time and frequency CSI-RS resources, and wherein:for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs;acquiring an effective downlink channel based on the precoded CSI-RS; andacquiring an actual downlink channel based on the channel measurement CSI-RS.

19. A method comprising:transmitting, at a channel state information reference signal (CSI-RS) instance and to a first terminal device, a channel measurement CSI-RS and a precoded CSI-RS, wherein at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and wherein:for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs.

20. An apparatus comprising:means for receiving, at a channel state information reference signal (CSI-RS) instance and from a network device, a channel measurement CSI-RS and a precoded CSI-RS, wherein at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for a first terminal device with the same time and frequency CSI-RS resources, and wherein:for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs;means for acquiring an effective downlink channel based on the precoded CSI-RS; and means for acquiring an actual downlink channel based on the channel measurement CSI-RS.

21. An apparatus comprising:means for transmitting, at a channel state information reference signal (CSI-RS) instance and to a first terminal device, a channel measurement CSI-RS and a precoded CSI-RS, wherein at the CSI-RS instance, the channel measurement CSI-RS and the precoded CSI-RS are scheduled for the first terminal device with the same time and frequency CSI-RS resources, and wherein:for the first terminal device, a first code division multiplexing (CDM) code is applied to channel measurement CSI-RSs, and a second CDM code is applied to precoded CSI-RSs, and for a second terminal device, the first CDM code is for precoded CSI-RSs, and the second CDM code is for channel measurement CSI-RSs.

22. A computer readable medium comprising program instructions for causing an apparatus to perform at least method of any of claims 18-19.

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