WO2024092666A1

WO2024092666A1 - Methods, devices, and medium for communication

Info

Publication number: WO2024092666A1
Application number: PCT/CN2022/129674
Authority: WO
Inventors: Yukai GAO; Peng Guan; Gang Wang
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2022-11-03
Filing date: 2022-11-03
Publication date: 2024-05-10
Anticipated expiration: 2025-05-03
Also published as: JP2025536602A

Abstract

Example embodiments of the present disclosure relate to an effective mechanism for processing the CSI reports. In this solution, the terminal device receives, from a network device, at least one configuration for one channel state information (CSI), wherein the at least one configuration indicates at least one first number of first vectors, at least one first number of second vectors and a number of a first plurality of channel state information reference signal (CSI-RS) resources; determining a second plurality of CSI-RS resources, wherein the second plurality of CSI-RS resources is same as or a subset of the first plurality of CSI-RS resources; determining at least one of: at least one second number of selected first vectors based on the second plurality of CSI-RS resources and at least one second number of selected second vectors based on the second plurality of CSI-RS resources and the at least one configuration; and transmitting, based on the at least one configuration, the CSI to the network device. In this way, the CSI report may be adaptable for the scenario where a coherent joint transmission based on multi-TRP is supported.

Description

METHODS, DEVICES, AND MEDIUM FOR COMMUNICATION

FIELD

Example embodiments of the present disclosure generally relate to the field of communication techniques and in particular, to methods, devices, and medium for configuring and transmitting the channel state information (CSI) feedback.

BACKGROUND

In order to meet the increasing wireless data traffic demand, a plurality of schemes have been proposed and implemented, where the multiple input multiple output (MIMO) technology is considered as one powerful scheme to achieve high data throughputs in the communication system. MIMO includes features that facilitate utilization of a large number of antenna elements at a network device (such as, a base station, BS) for both sub-6GHz and over-6GHz frequency bands.

Generally speaking, during the communication between the terminal device and the network device, the terminal device needs to report CSI feedback to the network device, such that the network device may understand the network condition and make a more proper subsequent schedule. Further, transmission via more than one transmission reception point (TRP) which also referred to as the multi-TRP transmission is expected to be supported. In case of the multi-TRP transmission, more parameters needed to be reported to the network device compared with single-TRP transmission. Thus, it is desirable to further discuss how to transmit the CSI feedback with more parameters to the network efficiently.

SUMMARY

In general, embodiments of the present disclosure provide methods, devices and computer storage media of configuring and transmitting the CSI feedback.

In a first aspect, there is provided a method of communication performed by a terminal device. The method comprises: receiving, at a terminal device and from a network device, at least one configuration for one channel state information (CSI) , wherein the at least one configuration indicates at least one first number of first vectors, at least one first number of second vectors and a number of a first plurality of channel state information reference signal (CSI-RS) resources; determining a second plurality of CSI-RS resources, wherein the second plurality of CSI-RS resources is same as or a subset of the first plurality of CSI-RS resources; determining at least one of: at least one second number of selected first vectors based on the second plurality of CSI-RS resources and at least one second number of selected second vectors based on the second plurality of CSI-RS resources and the at least one configuration; and transmitting, based on the at least one configuration, the CSI to the network device.

In a second aspect, there is provided a method of communication performed by a network device. The method comprises: transmitting, at a network device and to a terminal device, at least one configuration for one channel state information (CSI) , wherein the at least one configuration indicates at least one first number of first vectors, at least one first number of second vectors and a number of a first plurality of channel state information reference signal (CSI-RS) resources; and receiving, based on the at least one configuration, the CSI from the terminal device.

In a third aspect, there is provided a terminal device. The terminal device includes a processing unit; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to the first aspect.

In a fourth aspect, there is provided a network device. The network device includes a processing unit; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to the second aspect.

In a fifth aspect, there is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to any of the above first and second aspects.

Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some example embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

FIG. 1 illustrates a signaling flow according to some embodiments of the present disclosure;

FIG. 2A illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

FIG. 2B illustrates another example communication environment in which example embodiments of the present disclosure can be implemented;

FIG. 2C illustrates a schematic diagram of spatial domain, frequency domain and doppler/time domain basis;

FIG. 3 illustrates a signaling chart illustrating a process for communication according to some embodiments of the present disclosure;

FIG. 4 illustrate an example method according to some embodiments of the present disclosure;

FIG. 5 illustrates an example method performed by the terminal device according to some embodiments of the present disclosure;

FIG. 6 illustrates an example method performed by the network device according to some embodiments of the present disclosure; and

FIG. 7 illustrates a simplified block diagram of an apparatus that is suitable for implementing example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some 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 limitations as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

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.

As used herein, the term ‘terminal device’ refers to any device having wireless or wired communication capabilities. Examples of the terminal device include, but not limited to, user equipment (UE) , personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, tablets, wearable devices, internet of things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, device on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for Integrated Access and Backhaul (IAB) , Space borne vehicles or Air borne vehicles in Non-terrestrial networks (NTN) including Satellites and High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) , eXtended Reality (XR) devices including different types of realities such as Augmented Reality (AR) , Mixed Reality (MR) and Virtual Reality (VR) , the unmanned aerial vehicle (UAV) commonly known as a drone which is an aircraft without any human pilot, devices on high speed train (HST) , or image capture devices such as digital cameras, sensors, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. The ‘terminal device’ can further has ‘multicast/broadcast’ feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also incorporate one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM. The term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.

The term “network device” refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate. Examples of a network device include, but not limited to, a Node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNB) , a transmission reception point (TRP) , a remote radio unit (RRU) , a radio head (RH) , a remote radio head (RRH) , an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS) , and the like.

The terminal device or the network device may have Artificial intelligence (AI) or Machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.

The terminal or the network device may work on several frequency ranges, e.g. FR1 (410 MHz to 7125 MHz) , FR2 (24.25GHz to 71GHz) , frequency band larger than 100GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connection with the network devices under Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.

The embodiments of the present disclosure may be performed in test equipment, e.g. signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator.

In some embodiments, the terminal device may be connected with a first network device and a second network device. One of the first network device and the second network device may be a master node and the other one may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs) . In some embodiments, the first network device may be a first RAT device and the second network device may be a second RAT device. In some embodiments, the first RAT device is eNB and the second RAT device is gNB. Information related with different RATs may be transmitted to the terminal device from at least one of the first network device or the second network device. In some embodiments, first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device. In some embodiments, information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.

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. The term ‘includes’ and its variants are to be read as open terms that mean ‘includes, but is not limited to. ’ The term ‘based on’ is to be read as ‘at least in part based on. ’ The term ‘one embodiment’ and ‘an embodiment’ are to be read as ‘at least one embodiment. ’ The term ‘another embodiment’ is to be read as ‘at least one other embodiment. ’ The terms ‘first, ’ ‘second, ’ and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

In some examples, values, procedures, or apparatus are referred to as ‘best, ’ ‘lowest, ’ ‘highest, ’ ‘minimum, ’ ‘maximum, ’ or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

As discussed above, the CSI feedback is important in the wireless communication network. In the 3rd-generation partnership project (3GPP) release 18, some discussions for CSI enhancement are expected to be discussed, for example. It is expected that CSI enhancement for a high/medium velocity and for coherent joint transmission (CJT) will be specified and the number of CSI-RS ports per resource may be at least one of {2, 4, 8, 12, 16, 24, 32} .

In some embodiments, the terminal device may receive, from the network device, at least one configuration for one channel state information (CSI) , wherein the at least one configuration may indicate at least one first number of first vectors, at least one first number of second vectors and a number of a first plurality of channel state information reference signal (CSI-RS) resources.

In some embodiments, the terminal device may determine a second plurality of CSI-RS resources, wherein the second plurality of CSI-RS resources may be same as or a subset of the first plurality of CSI-RS resources. In some embodiments, the terminal device may determine at least one of: at least one second number of selected first vectors based on the second plurality of CSI-RS resources and at least one second number of selected second vectors based on the second plurality of CSI-RS resources and the at least one configuration. In some embodiments, the terminal device may transmit, based on the at least one configuration, the CSI to the network device. In some embodiments, the terminal device may transmit the CSI based on at least one of the at least one second number of selected first vectors and the at least one second number of selected second vectors.

In some embodiments, the at least one first number of first vectors may comprise a first set of values, and each value in the first set of values may indicate a first number of first vectors corresponding to each one of the first plurality of CSI-RS resources. In some embodiments, a number of the first set of values may be same as a number of the first plurality of CSI-RS resources. In some embodiments, the at least one second number of first vectors may comprise a second set of values, and each value in the second set of values may indicate a second number of first vectors corresponding to each one CSI-RS resource in the second plurality of CSI-RS resources. In some embodiments, a number of the second set of values may be same as a number of the second plurality of CSI-RS resources. In some embodiments, a value in the second set of values corresponding to a CSI-RS resource may be equal to or less than a value in the first set of values corresponding to the same CSI-RS resource. In some embodiments, each value in the second set of values may be no less than 1 or 2.

In some embodiments, the at least one second number of selected first vectors may comprise a first value for the first vectors and a second value for the first vectors, and the first value for the first vectors may indicate a second number of selected first vectors corresponding to a reference CSI-RS resource in the second plurality of CSI-RS resources, and the second value for the first vectors may indicate a second number of selected first vectors corresponding to remaining CSI-RS resources except the reference CSI-RS resource in the second plurality of CSI-RS resources.

In some embodiments, the at least one first number of first vectors may comprise a third value for the first vectors and a fourth value for the first vectors, and the third value for the first vectors may be larger than or equal to the first value for the first vectors, and the fourth value for the first vectors may be larger than or equal to the second value for the first vectors.

In some embodiments, the terminal device may determine an index of a second vector corresponding to each one of the second plurality of CSI-RS resources. In some embodiments, the terminal device may determine a set of selected second vectors from a first plurality of second vectors corresponding to each one of the second plurality of CSI-RS resources. In some embodiments, the first plurality of second vectors corresponding to each one of the second plurality of CSI-RS resources may be based on the first index of the second vector corresponding to each one of the second plurality of CSI-RS resources and the at least one second number of selected second vectors.

In some embodiments, the terminal device may determine a first field for indicating a set of selected second vectors corresponding to a reference CSI-RS resource in the second plurality of CSI-RS resources. In some embodiments, the set of selected second vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources may comprise a second vector corresponding to a strongest coefficient indication.

In some embodiments, the terminal device may determine a second field for indicating a set of selected second vectors corresponding to one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources. In some embodiments, the set of selected second vectors corresponding to the one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources may comprise a second vector with an index based on a first index of the second vector corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources and a second index of the second vector to the one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources.

In some embodiments, the terminal device may determine a set of selected second vectors corresponding to a reference CSI-RS resource in the second plurality of CSI-RS resources. In some embodiments, the terminal device may determine an offset for one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resource. S. In some embodiments, the terminal device may determine a set of selected second vectors corresponding to one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources based on the offset and the set of selected second vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources. In some embodiments, the offset may be relative to at least one of: a first one index of the set of selected second vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources; a last one index of the set of selected second vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources; and a first index of the second vector corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources.

In some embodiments, the at least one configuration may indicate or comprise at least one set of parameters. In some embodiments, each set of parameters may indicate or comprise a first parameter, a second parameter and a third parameter. In some embodiments, the at least one second number of selected second vectors may be determined based on a maximum value of the second parameters among the at least one set of parameters. In some embodiments, the at least one set of parameters may comprise a first value of the second parameter and a second value of the second parameter. In some embodiments, the at least one second number of selected second vectors may be determined based on the first value of the second parameter when the number of the second plurality of CSI-RS resources is 1. In some embodiments, the at least one second number of selected second vectors may be determined based on the second value of the second parameter when the number of the second plurality of CSI-RS resources is 2 or 3 or 4.

In some embodiments, the terminal device may determine a size of a bitmap indicating non zero coefficients corresponding to the second plurality of CSI-RS resources. In some embodiments, the terminal device may determine a constraint of a total number of non zero coefficients corresponding to the second plurality of CSI-RS resources.

In some embodiments, the size of the bitmap indicating non zero coefficients and/or the constraint of the total number of non zero coefficients may be determined based on a maximum value of the third parameters among the at least one set of parameters. In some embodiments, the at least one set of parameters may comprise a first value of the third parameter and a second value of the third parameter. In some embodiments, the size of the bitmap indicating non zero coefficients corresponding to the second plurality of CSI-RS resources or the constraint of the total number of non zero coefficients corresponding to the second plurality of CSI-RS resources may be determined based on the first value of the third parameter when the number of the second plurality of CSI-RS resources is 1. In some embodiments, the size of the bitmap indicating non zero coefficients corresponding to the second plurality of CSI-RS resources or the constraint of the total number of non zero coefficients corresponding to the second plurality of CSI-RS resources may be determined based on the second value of the third parameter when the number of the second plurality of CSI-RS resources is 2 or 3 or 4.

In some embodiments, the at least one first number of first vectors may comprise more than one value, and each one of more than one value may indicate a number or a maximum number of first vectors to be selected corresponding to each one of the first plurality of CSI-RS resources. In some embodiments, the at least one first number of first vectors may be one single value, and the single value may indicate a total number or a maximum total number of first vectors to be selected corresponding to all of the first plurality of CSI-RS resources or corresponding to all of the second plurality of CSI-RS resources.

In some embodiments, the network device may transmit, to the terminal device, at least one configuration for one CSI, wherein the at least one configuration may indicate at least one first number of first vectors, at least one first number of second vectors and a number of a first plurality of channel state information reference signal (CSI-RS) resources. In some embodiments, the network device may receive, based on the at least one configuration, the CSI from the terminal device.

In some embodiments, it is expected to specify CSI reporting enhancement for a high/medium velocity by exploiting time-domain (TD) correlation/doppler-domain (DD) information to assist downlink precoding, targeting frequency range 1 (FR 1) . For example, Release 16/17 type-II codebook refinement, without modification to the spatial domain (SD) basis and frequency domain (FD) basis. For another example, UE reporting of TD channel properties measured via CSI-reference signal (RS) for tracking.

In some embodiments, it is expected to specify enhancements of CSI acquisition for CJT targeting FR1 and up to 4 TRPs, assuming ideal backhaul and synchronization as well as the same number of antenna ports across TRPs. For example, Release 16/17 type-II codebook refinement for CJT multi-TRP targeting FDD and its associated CSI reporting, taking into account throughput-overhead trade-off.

Fig. 1 illustrates a signaling chart illustrating process 100 among devices according to some example embodiments of the present disclosure. Only for the purpose of discussion, the process 100 will be described with reference to Fig. 2A or FIG. 2B. The process 100 may involve the terminal device 220 and the network device 210 shown in Fig. 2A or FIG. 2B.

In some embodiments, the network device 210 may transmit 1010 at least one configuration to the terminal device 220. In some embodiments, the terminal device 220 may transmit 1020 at least one codebook indicator to the network device 210. In some embodiments, the at least one codebook indicator may be determined based on the at least one configuration.

In some embodiments, a CSI report may be divided into two parts. For example, CSI part 1 (or part 1 or a first part of CSI) and CSI part 2 (or part 2 or a second part of CSI) . In some embodiments, CSI part 2 may be further divided into three groups. For example, CSI group 0, CSI group 1, and CSI group 2. In some embodiments, a CSI report may comprise PMI fields X ₁ and PMI fields X ₂. For example, PMI fields X ₁ may be comprised in CSI group 0. For another example, PMI fields X ₂ may be comprised in CSI group 1 and CSI group 2. For another example, a subset of PMI fields X ₂ may be comprised in CSI group 1, and the remaining of PMI fields X ₂ may be comprised in CSI group 2.

Below table 1 illustrates an example mapping order of CSI fields of one CSI report, CSI part 1.

Table 1 an example mapping order of CSI fields of one CSI report, CSI part 1

Below table 2 illustrates an example RI and CQI.

Table 2 an example RI and CQI

Further, the values of the rank indicator (RI) field are mapped to allowed rank indicator values with increasing order, where '0' is mapped to the smallest allowed rank indicator value. The values of the K ^NZ indicator field are mapped to the allowed values of K ^NZ, according to Clauses 5.2.2.2.5 and 5.2.2.2.6 of TS 38.214, with increasing order, where '0' is mapped to K ^NZ=1.

In some embodiments, a parameter of number of allowed rank indicator values (e.g. n _RI) may be configured by the network device.

In some embodiments, v may be the number of layers or the value of rank indicator field. For example, the number of layers or the value of the RI field may be reported by the terminal device to the network device.

Below table 3 illustrate an example RI and CQI.

Table 3 illustrates an example RI and CQI

The values of the rank indicator (RI) field may be mapped to allowed rank indicator values with increasing order, where '0' is mapped to the smallest allowed rank indicator value. The values of the K ^NZ indicator field are mapped to the allowed values of K ^NZ, according to Clauses 5.2.2.2.7 of TS 38.214, with increasing order, where '0' is mapped to K ^NZ=1.

In some embodiments, the terminal device may receive, from the network device, at least one configuration for CSI feedback, wherein the at least one configuration may include at least one of:

● a first plurality of CSI-RS resources,

● a second plurality of CSI-RS resources,

● a plurality of antenna ports for one CSI-RS resource in the first or second plurality of CSI-RS resources,

● at least one parameter for antenna port configuration, a configuration for codebook type, ● a configuration for reporting type,

● at least one parameter for codebook,

● the number of physical resource blocks (PRBs) in a bandwidth part (BWP) ,

● the number of a plurality of first subbands,

● a size of one first subband,

● the number of PRBs of one first subband,

● the number of a plurality of second subbands (e.g. represented as N ₃) ,

● a size of one second subband,

● the number of PRBs of one second subband,

● the number of a plurality of time units (e.g. represented as N ₄) ,

● a size of one time unit (e.g. represented as T _u or T _i) ,

● the number of slots/subslots/symbols of one time unit (e.g. represented as T _u or T _i) ,

● the number of a plurality of first vectors (e.g. represented as L) ,

● the number of a plurality of second vectors (e.g. represented as M _υ) ,

● the number of a plurality of third vectors (e.g. represented as M _d) ,

● a first parameter for codebook (e.g. represented as R) ,

● a second parameter for codebook (e.g. represented as p _v) ,

● a third parameter for codebook (e.g. represented as β) ,

● a fourth parameter for codebook (e.g. represented as R _d) ,

● a fifth parameter for codebook (e.g. represented as p _v, d) ,

● a sixth parameter for codebook (e.g. represented as β _d) and

● a seventh parameter for codebook (e.g. represented as M) .

In some embodiments, the terminal device may be configured with a number of PRBs for a bandwidth part (BWP) or with a size for the BWP. In some embodiments, the number of PRBs for the BWP (e.g. represented as

) may be a positive integer. For example, N _BWP may be a positive integer. For example,

In some embodiments, the terminal device may be configured with a starting position of the BWP (e.g. represented as

) . For example,

may be a non-negative integer. For example,

In some embodiments, the starting position of the BWP and the number of PRBs for the BWP may be configured in one higher layer parameter.

In some embodiments, first subband may correspond to a subband for CQI or CQI subband or CSI subband.

In some embodiments, the size of one first subband or the number of PRBs of one first subband may be represented as

and

is a positive integer. For example,

For example,

may be at least one of {4, 8, 16, 32} . In some embodiments,

may be based on the value of N _BWP. In some embodiments, if 24≤N _BWP≤72,

may be 4 or 8. For example,

may be configured to be 4 or 8 based on one higher layer parameter for subband. In some embodiments, if 73≤N _BWP≤144,

may be 8 or 16. For example,

may be configured to be 8 or 16 based on the higher layer parameter for subband. In some embodiments, if 145≤N _BWP≤275,

may be 16 or 32. For example,

may be configured to be 16 or 32 based on the higher layer parameter for subband.

In some embodiments, the terminal device 220 may be configured with a first plurality of CSI-RS resources. In some embodiments, the at least one configuration for the CSI may comprise or indicate the first plurality of CSI-RS resources. In some embodiments, the first plurality of CSI-RS resources may comprise N _TRPCSI-RS resource. In some embodiments, the number of CSI-RS resources in the first plurality of CSI-RS resources may be N _TRP. In some embodiments, N _TRP may be a positive integer, and 1≤N _TRP≤8. In some embodiments, N _TRP may be at least one of {1, 2, 3, 4} or at least one of {2, 3, 4} .

In some embodiments, each CSI-RS resource may be represented as t. In some embodiments, t may be a non-negative integer. For example, 0≤t≤N _TRP-1 or t∈ {0, 1, ... N _TRP-1} . In some embodiments, the first CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS resource with index t=0. In some embodiments, the second CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS resource with index t=1. In some embodiments, the third CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS resource with index t=2. In some embodiments, the fourth CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS resource with index t=3. In some embodiments, the n-th CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS with index t=n-1. In some embodiments, n may be a positive intger. For example, 1≤n≤N _TRP or n∈ {1, 2, ... N _TRP} .

In some embodiments, t may be a positive integer. For example, 1≤t≤N _TRP or t∈ {1, 2, ... N _TRP} . In some embodiments, the first CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS resource with index t=1. In some embodiments, the second CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS resource with index t=2. In some embodiments, the third CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS resource with index t=3. In some embodiments, the fourth CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS resource with index t=4. In some embodiments, the t-th CSI-RS resource in the first plurality of CSI-RS resources may be represented as CSI-RS with index t.

In some embodiments, the terminal device 220 may indicate or select or determine or report a second plurality of CSI-RS resources based on the first plurality of CSI-RS resources. In some embodiments, the second plurality of CSI-RS resources may be same as the first plurality of CSI-RS resources. In some embodiments, the second plurality of CSI-RS resources may be a subset of the first plurality of CSI-RS resources. In some embodiments, the second plurality of CSI-RS resources may comprise N CSI-RS resource. In some embodiments, the second plurality of CSI-RS resources may comprise N CSI-RS resource. In some embodiments, the number of CSI-RS resources in the second plurality of CSI-RS resources may be N. In some embodiments, N may be a positive integer, and 1≤N≤N _TRP. In some embodiments, N may be at least one of {1, 2, 3, 4} or at least one of {2, 3, 4} . In some embodiments, N may be less than or equal to N _TRP.

In some embodiments, the second plurality of CSI-RS resources may be indicated or reported based on a first bitmap. In some embodiments, the number of bits in the first bitmap may be N _TRP. In some embodiments, a bit in the bitmap may be represented as b _t, and the value of b _t may be either 0 or 1. In some embodiments, the bit b _t in the bitmap may indicate whether the corresponding CSI-RS resource with index t in the first plurality of CSI-RS resources selected or not. In some embodiments, the bit b _t in the bitmap may indicate whether the corresponding CSI-RS resource with index t in the first plurality of CSI-RS resources included or selected in the second plurality of CSI-RS resources or not. In some embodiments, the first bitmap may be represented as {b _t} , wherein 1≤t≤N _TRP or 0≤t≤N _TRP-1. In some embodiments, the first bitmap may be {b ₀, b ₁} or {b ₁, b ₂} whenN _TRP=2. In some embodiments, the first bitmap may be {b ₀, b ₁, b ₂} or {b ₁, b ₂, b ₃} whenN _TRP=3. In some embodiments, the first bitmap may be {b ₀, b ₁, b ₂, b ₃} or {b ₁, b ₂, b ₃, b ₄} whenN _TRP=4. In some embodiments, a CSI-RS resource t in the first plurality of CSI-RS resources corresponding to a bit value b _t is selected or is included in the secnod plurality of CSI-RS resources if the value b _t=1. In some embodiments, at least one bit in the bitmap may be with value 1.

In some embodiments, there may be a reference CSI-RS resource in the first plurality of CSI-RS resources or in the second plurality of CSI-RS resources. In some embodiments, the reference CSI-RS resource may be a CSI-RS resource in the second plurality of CSI-RS resources corresponding to a strongest coefficient indication or a strongest amplitude coefficient or an indication in the bitmap for non zero coefficients indication. In some embodiments, the reference CSI-RS resource may be the first one of CSI-RS resource or the last one of CSI-RS resource or the latest one of CSI-RS resource in time in the first plurality of CSI-RS resources. In some embodiments, the reference CSI-RS resource may be the first one of CSI-RS resource or the last one of CSI-RS resource or the latest one of CSI-RS resource in time in the second plurality of CSI-RS resources.

In some embodiments, for each one CSI-RS resource in the first plurality of CSI-RS resources, there may be P ports. In some embodiments, P may be a positive integer. In some embodiments, P may be at least one of {2, 4, 8, 12, 16, 24, 32} .

In some embodiments, a total or a maximum value of P*N _TRP may be at least one of {4, 8, 12, 16, 24, 32, 36, 48, 64, 72, 96, 128} .

In some embodiments, the terminal device may indicate or report at least one capability parameters to the network device. In some embodiments, different capability parameters may correspond to different values of P*N _TRP. For example, a first capability parameter may indicate that the terminal device support a maximum value of 32 for total number of ports in the first plurality of CSI-RS resources. For another example, a second capability parameter may indicate that the terminal device support a maximum value of 64 for total number of ports in the first plurality of CSI-RS resources. For another example, a third capability parameter may indicate that the terminal device support a maximum value of 128 for total number of ports in the first plurality of CSI-RS resources.

In some embodiments, the terminal device 220 may be configured with a first total number or first maximum number of first vectors (For example, at least one first number of first vectors. For example, represented as L _tot or L _max) . For example, the first total number or the first maximum number may be based on the assumption of all CSI-RS resources in the first plurality of CSI-RS resources. In some embodiments, the at least one configuration may indicate or comprise the first total or maximum number of first vectors. In some embodiments, the terminal device 220 may determine or report a second total number or a second maximum number of first vectors (For example, at least one second number of selected first vectors. For example, represented as L _tot, r or L _max, r) based on the second plurality of CSI-RS resources or based on the first bitmap or based on the number of CSI-RS resources in the second plurality of CSI-RS resources (For example, the value of N) .

In some embodiments, the value of L _tot or L _max may be configured or may be determined based on a first set of values, and each value in the first set of values may indicate a first number of first vectors corresponding to each one of the first plurality of CSI-RS resources. In some embodiments, the first set of values may include N _TRP values. In some embodiments, the value of L _tot or L _max may be a positive integer. For example, 2≤L _tot≤24 or 2≤L _max≤24.. For another example, 2≤L _tot≤16 or 2≤L _max≤16. For another example, L _tot or L _max may be at least one of {2, 3, 4, 6, 8, 9, 12, 16} .

In some embodiments, a value in the first set of values may be represented as L _t. In some embodiments, the value of L _t may be at least one of {1, 2, 3, 4, 5, 6} . In some embodiments, the first set of values may be {L ₀, L ₁} or {L ₁, L ₂} when N _TRP=2. In some embodiments, the first bitmap may be {L ₀, L ₁, L ₂} or {L ₁, L ₂, L ₃} when N _TRP=3. In some embodiments, the first bitmap may be {L ₀, L ₁, L ₂, L ₃} or {L ₁, L ₂, L ₃, L ₄} whenN _TRP=4. In some embodiments, the value of L ₀ and/or L ₁ and/or L ₂ and/or L ₃ and/or L ₄ may be same or different. In some embodiments,

or

In some embodiments, the terminal device 220 may determine a second total number or a second maximum number of first vectors (For example, at least one second number of first vectors. For example, represented as L _tot, r or L _max, r) based on the second plurality of CSI-RS resources or based on the first bitmap or based on the number of CSI-RS resources in the second plurality of CSI-RS resources (For example, the value of N) . In some embodiments, the terminal device 220 may determine or report a second set of values based on the second plurality of CSI-RS resources or based on the first bitmap or based on the number of CSI-RS resources in the second plurality of CSI-RS resources (For example, the value of N) , and each value in the second set of values may indicate a second number of first vectors corresponding to each one CSI-RS resource in the second plurality of CSI-RS resources. In some embodiments, the value of L _tot, r or L _max, r may be same or less than the value of L _tot or L _max, and the value of L _tot, r or L _max, r may be same or larger than N or N _TRP .

In some embodiments, the number of values in the second set of values may be same as the number of CSI-RS resources in the second plurality of CSI-RS resources or the value N or the number of bits with value 1 in the first bitmap.

In some embodiments, a value in the second set of values may be represented as L _ts. In some embodiments, ts may be a positive integer. For example, 1≤ts≤N _TRP or ts∈ {1, 2, ... N _TRP} . In some embodiments, the value of L _t, smay be at least one of {1, 2, 3, 4, 5, 6} . In some embodiments, the value of L _ts may correspond to the value of L _t with the corresponding bit b _t=1 in the first bitmap. In some embodiments, the value of L _ts may be L _ts=L _t or 1≤L _ts≤L _t, and the value of bit b _ts=1 or b _t=1 in the first bitmap.

In some embodiments, if the value of bit b _ts=1 or b _t=1 in the first bitmap, the value of the value of L _ts may be L _ts=L _t or 1≤L _ts≤L _t. In some embodiments, if the value of bit b _ts=0 or b _t=0 in the first bitmap, the value of the value of L _ts may be L _ts=0.

In some embodiments, when N _TRP=4, and when the first bitmap is {1, 1, 0, 1} , then there may be 3 CSI-RS resources in the second plurailty of CSI-RS resources. And the 3 CSI-RS resource may be the first one, the second one and the fourth one CSI-RS resources in the first plurailty of CSI-RS resources. And the second set of values may be {L ₁, L ₂, L ₄} or the second set of values may be {L ₁, L ₂, 0, L ₄} . In some embodiments, the second total number or the second maximum number of first vectors may be L ₁ + L ₂+L ₄.

In some embodiments, the second set of values may be {L _0, s, L _1, s} or {L _1, s, L _2, s} whenN _TRP=2. In some embodiments, the first bitmap may be {L _0, s, L _1, s, L _2, s} or {L _1, s, L _2,s, L _3, s} whenN _TRP=3. In some embodiments, the first bitmap may be {L _0, s, L _1, s, L _2, s, L _3,s} or {L _1, s, L _2, s, L _3, sL _4, s} whenN _TRP=4. In some embodiments, the value of L _0, sand/or L _1, sand/or L _2, sand/or L _3, sand/or L _4, smay be same or different. In some embodiments,

or

In some embodiments, the second number of selected first vectors corresponding to the first CSI-RS resource in the second plurality of CSI-RS resources may be L _1, s∈{1,2, ... max (L _tot-N, L ₁) } or L _1, s∈ {1, 2, ... L _tot-N} . In some embodiments, the second number of selected first vectors corresponding to the second CSI-RS resource in the second plurality of CSI-RS resources may be L _2, s∈ {1, 2, ... max (L _tot-L ₁, L ₂) } . or L _2, s∈ {1, 2, ... max (L _tot-L ₁, L _tot-N) } . In some embodiments, the second number of selected first vectors corresponding to the third CSI-RS resource in the second plurality of CSI-RS resources may be L _3, s∈ {1, 2, ... max (L _tot-L ₁-L ₂, L ₃) } . or L _3, s∈ {1, 2, ... max (L _tot-L ₁-L ₂, L _tot-N) } . In some embodiments, the second number of selected first vectors corresponding to the fourth CSI-RS resource in the second plurality of CSI-RS resources may be L _4, s∈ {1, 2, ... max (L _tot-L ₁-L ₂-L ₃, L ₄) } . or L _4, s∈ {1, 2, ... max (L _tot-L ₁-L ₂-L ₃, L _tot-N) } .

In some embodiments, the minimum value of the second total number of selected first vectors may be N or or N+1 or min (N+1, N _TRP) . In some embodiments, for the reference CSI-RS resource, the minimum value of the second total number of selected first vectors may be 1 or 2. In some embodiments, the minimum value of number of selected first vectors for each CSI-RS resource in the second plurality of CSI-RS resources may be 1 or 2.

In some embodiments, the at least one configuration may configure or indicate a single value of the first total number or first maximum number of first vectors. In some embodiments, the at least one first number of first vectors may be the single value. For example, the single value may be represented as L _tot or L _max. In some embodiments, the second total number of second maximum number of selected first vectors (For example, represented as L _tot, r or L _max, r) may be same as or less than the value of L _tot or L _max.

In some embodiments, a first number or a maximum number of first vectors corresponding to each CSI-RS resource in the first plurality of CSI-RS resources may be determined based on the single value L _tot or L _max and/or the value of N. In some embodiments, the first number or the maximum number of first vectors corresponding to each CSI-RS resource in the first plurality of CSI-RS resources may be L _t=L _max/N or

or

In some embodiments, the first number or the maximum number of first vectors corresponding to the reference CSI-RS resource in the first plurality of CSI-RS resources may be L _t=2*L _max/N or

or

In some embodiments, the first number or the maximum number of first vectors corresponding to one CSI-RS resource except the reference CSI-RS resource in the first plurality of CSI-RS resources may be L _t=L _max/ (N+1) or

or

In some embodiments, a second number or a maximum number of selected first vectors corresponding to each CSI-RS resource in the second plurality of CSI-RS resources may be determined based on the single value L _tot or L _max and/or the value of N. In some embodiments, the second number or the maximum number of selected first vectors corresponding to each CSI-RS resource in the second plurality of CSI-RS resources may be L _t=L _max/N or

or

In some embodiments, the second number or the maximum number of selected first vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources may be L _t=2*L _max/N or

or

In some embodiments, the second number or the maximum number of selected first vectors corresponding to one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources may be L _t=L _max/ (N+1) or

or

In some embodiments, the at least one first number may comprise a plurality of values of the total number or the maximum number of first vectors. In some embodiments, there may be a plurality of values of the total number or the maximum number of first vectors. For example, the plurality of values may be explicitly configured by the network device. In some embodiments, each one of the plurality of values may indicate or may be associated with a total number or a maximum number of first vectors corresponding to a value of the number of second plurality of CSI-RS resources or corresponding to a value of N.In some embodiments, the first value in the plurality of values may be a total number or a maximum number of first vectors corresponding to the number of second plurality of CSI-RS resources is same as 1 or N=1. In some embodiments, the second value in the plurality of values may be a total number or a maximum number of first vectors corresponding to the number of second plurality of CSI-RS resources is same as 2 or N=2. In some embodiments, the third value in the plurality of values may be a total number or a maximum number of first vectors corresponding to the number of second plurality of CSI-RS resources is same as 3 or N=3. In some embodiments, the fourth value in the plurality of values may be a total number or a maximum number of first vectors corresponding to the number of second plurality of CSI-RS resources is same as 4 or N=4. In some embodiments, the first or the last value in the plurality of values may be a total number or a maximum number of first vectors corresponding to the number of second plurality of CSI-RS resources is same as N _TRP or N=N _TRP.

In some embodiments, the at least one configuration may configure or indicate a first value for a total number or a maximum number of the first vectors and a second value for a total number of a maximum number the first vectors. In some embodiments, the at least one configuration may configure or indicate two values of the total number or the maximum number of first vectors. In some embodiments, the at least one first number of first vectors may comprise two values of the total number or the maximum number of first vectors. In some embodiments, the two values may be a first value for the first vectors and a second value for the first vectors. In some embodiments, the first value for the first vectors may indicate a total number of first vectors corresponding to all CSI-RS resources in the second plurality of CSI-RS resources if the number of CSI-RS resources in the second plurality of CSI-RS resources is larger than 1, and the second value for the first vectors may indicate a total number of first vectors corresponding to the CSI-RS resource in the second plurality of CSI-RS resources if there is only one CSI-RS resource in the second plurality of CSI-RS resources.

In some embodiments, the at least one configuration may configure or indicate a first value for the first vectors and a second value for the first vectors. In some embodiments, the at least one configuration may configure or indicate two values of the first number or first maximum number of first vectors. In some embodiments, the at least one first number of first vectors may comprise two values of the first number or first maximum number of first vectors. In some embodiments, the two values may be a first value for the first vectors and a second value for the first vectors. In some embodiments, the first value for the first vectors may indicate a first number of first vectors corresponding to the reference CSI-RS resource in the first plurality of CSI-RS resources, and the second value for the first vectors may indicate a first number of first vectors corresponding to each one of the remaining CSI-RS resources except the reference CSI-RS resource in the first plurality of CSI-RS resources. In some embodiments, the two values may be a first value for the first vectors and a second value for the first vectors. In some embodiments, the first value for the first vectors may indicate a second number of selected first vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources, and the second value for the first vectors may indicate a second number of selected first vectors corresponding to each one of the remaining CSI-RS resources except the reference CSI-RS resource in the second plurality of CSI-RS resources.

In some embodiments, the first value for the first vectors may be represented as Lt_1 and the second value for the first vectors may be represented as Lt_2. In some embodiments, Lt_1 and/or Lt_2 may be a positive integer. For example Lt_1 and/or Lt_2 may be at least one of {1, 2, 3, 4, 5, 6} . In some embodiments, Lt_1 may be no less than Lt_2. In some embodiments, Lt_2 may be ceil (Lt_1 /2) or floor (Lt_1 /2) or max (ceil (Lt_1 /2, 2) ) or max (floor (Lt_1 /2, 2) ) .

In some embodiments, the at least one configuration may configure or indicate a single value for the first vectors (For example, represented as Lt_1) . In some embodiments, the at least one configuration may configure or indicate the single value of a number or a maximum number of first vectors. In some embodiments, the at least one first number of first vectors may comprise the single values of the number or the maximum number of first vectors. In some embodiments, the single value for the first vectors may indicate a first number or a first maximum number of first vectors corresponding to the reference CSI-RS resource in the first plurality of CSI-RS resources. In some embodiments, for each one of the remaining CSI-RS resources except the reference CSI-RS resource in the first plurality of CSI-RS resources, the value of the first number or a first maximum number of first vectors may be ceil (Lt_1/2) or floor (Lt_1/2) or max (ceil (Lt_1/2, 2) ) or max (floor (Lt_1/2, 2) ) . In some embodiments, the single value for the first vectors may indicate a second number or a maximum number of selected first vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources, and for each one of the remaining CSI-RS resources except the reference CSI-RS resource in the second plurality of CSI-RS resources, the value of the second number or a maximum number of selected first vectors may be ceil (Lt_1/2) or floor (Lt_1/2) or max (ceil (Lt_1/2, 2) ) or max (floor (Lt_1/2, 2) ) .

In some embodiments, the index of the reference CSI-RS resource of the second plurality of CSI-RS resources or of the first plurality of CSI-RS resources may be indicated or reported by the terminal device. In some embodiments, the size of the field for indicating the index of the reference CSI-RS resource may be ceil (log2 (N _TRP) ) . For example, the size of the field for indicating the index of the reference CSI-RS resource may be 0 or 1 or 2. In some embodiments, the field for indicating the index of the reference CSI-RS resource may be in the CSI part 1 or a first part of CSI. In some embodiments, the size of the field for indicating the index of the reference CSI-RS resource may be ceil (log2 (N) ) . For example, the size of the field for indicating the index of the reference CSI-RS resource may be 0 or 1 or 2. In some embodiments, the field for indicating the index of the reference CSI-RS resource may be in the CSI part 2 or a second part of CSI. For example, if the number of CSI-RS resources in the second plurality of CSI-RS resources is larger than 1.

In some embodiments, the index of the reference CSI-RS resource may be based on a 1 bit field and the indication of strongest coefficient. For example, if the number of CSI-RS resources in the second plurality of CSI-RS resources is larger than 1.

In some embodiments, if the number of CSI-RS resources in the second plurality of CSI-RS resources is 1, the value of the number or the maximum number of selected first vectors for the one CSI-RS resource in the second plurality of CSI-RS resources may be a maximum value among the number or the maximum number of first vectors for each one CSI-RS resource in the first plurality of CSI-RS resources. For example, the value of the number or the maximum number of selected first vectors for the one CSI-RS resource in the second plurality of CSI-RS resources may be max (L _t) or min (4, max (L _t) ) .

In some embodiments, the terminal device may determine or report a number of first vectors (for example, represented as L _t, s) for each one CSI-RS resource in the second plurality of CSI-RS resources based on the first number of first vectors or the second number of selected first vectors corresponding to the CSI-RS resource. For example, bit size for a field indicating or reporting the number of first vectors for the CSI-RS resource may be ceil (log ₂ (C (N ₁*N ₂, L _t, s) ) or ceil (log ₂ (nchoosek (N ₁*N ₂, L _t, s) ) . In some embodiments, C (a, b) may be nchoosek (a, b) .

In some embodiments, the at least one second number of selected first vectors corresponding to each CSI-RS resource in the second plurality of CSI-RS resources may be indicated or reported to the network device. For example, in CSI part 1 or a first part of CSI. In some embodiments, the bit size for the field for indicating the at least one second number of selected first vectors corresponding to each CSI-RS resource in the second plurality of CSI-RS resources may be

or

In some embodiments, the terminal device may be configured with at least set of parameters or the at least one configuration may comprise or indicate at least one set of parameters. In some embodiments, in each set of parameters, there may be at least one of a second parameter p _v, a third parameter β and a first parameter R. In some embodiments, the number of sets of the parameters may be 1 or 2 or 3 or 4. In some embodiments, the number of sets of the parameters may be same as the number of CSI-RS resources in the first plurality of CSI-RS resources.

In some embodiments, each set of parameters may correspond to one CSI-RS resource in the first plurality of CSI-RS resources. In some embodiments, the value of p _v and/or β for the CSI reporting may be determined based on the maximum value among the values of p _v and/or the maximum value among the values of β corresponding to the CSI-RS resources in the first plurality of CSI-RS resources or in the second plurality of CSI-RS resources.

In some embodiments, in a set of parameters with index t, there may be a second parameter p _v, t and/or a third parameter β _t. In some embodiments, the (final) value of p _v and/or the final value of β for the CSI reporting may be determined as max _t (p _v, t) and/or max _t (β _t) . In some embodiments, the (final) value of p _v and/or the final value of β for the CSI reporting may be determined based on the value of second parameter and/or the value of third parameter corresponding to the reference CSI-RS resource. In some embodiments, the (final) value of p _v and/or the final value of β for the CSI reporting may be determined as p _{v, t_f} and/or β _{t_f}, wherein t_f may be the index of the reference CSI-RS resource.

In some embodiments, if there is only one CSI-RS resource in the second plurality of CSI-RS resources, the value of the second parameter and/or the value of the third parameter corresponding to the one selected CSI-RS resource may be applied for the CSI reporting.

In some embodiments, the at least one configuration may indicate or comprise a first set of parameters and a second set of parameters. In some embodiments, in the first set of parameters, there may be a second parameter p _v, 1 and/or a third parameter β ₁. In some embodiments, in the second set of parameters, there may be a second parameter p _v, 2 and/or a third parameter β ₂. In some embodiments, if the number of CSI-RS resources in the second plurality of CSI-RS resources is larger than 1, the first set of parameters (for example, the second parameter p _v, 1 and/or the third parameter β ₁ ) may be applied for the CSI reporting. In some embodiments, if the number of CSI-RS resources in the second plurality of CSI-RS resources is 1, the second set of parameters (for example, the second parameter p _v, 2 and/or the third parameter β ₂ ) may be applied for the CSI reporting. In some embodiments, p _v, 2≥p _v, 1. In some embodiments, β ₂≥β ₁.

In some embodiments, for CSI-RS resource in the second plurality of CSI-RS resources (For example, represented as t) , a set of second vectors (For example, represented as W _f, , t) may be selected or reported and/or determined.

In some embodiments, for the reference CSI-RS resource in the second plurality of CSI-RS resources, the terminal device may determine and/or report a first offset for the second vectors (For example, represented as M _initial) . In some embodiments, M _initial may be an integer. For example, M _initial∈ {-2M _υ+1, -2M _υ+2, …, 0} . In some embodiments, M _υ may be the number of second vectors for the reference CSI-RS resource or for each one CSI-RS resource in the second plurality of CSI-RS resources. In some embodiments, for the reference CSI-RS resource in the second plurality of CSI-RS resources, the terminal device may determine a first plurality of second vectors (For example, a first window for the second vectors) . In some embodiments, the first plurality of second vectors or the first window may be a plurality of second vectors with index {M _initial, (M _initial+1) mod N ₃, (M _initial+2) mod N ₃, …, (M _initial+2M _υ-1) mod N ₃, (M _initial+2M _υ) mod N ₃} . In some embodiments, the number of second vectors in the first plurality of second vectors or the size of the first window may be M _υ. In some embodiments, the first plurality of second vectors may be selected or determined from a group or a whole set of N ₃ second vectors. In some embodiments, when N ₃> T _N. In some embodiments, T _N may be a positive integer. For example, 1≤T _N≤50. For example, T _N=19.

In some embodiments, for the reference CSI-RS resource in the second plurality of CSI-RS resources, the terminal device may determine and/or report a first set of second vectors selected from the group or the whole set of N ₃ second vectors. In some embodiments, a first size for the field indicating the first set of second vectors corresponding to the reference CSI-RS resource may be

or

In some embodiments, when N ₃≤ 19. For example, based on remapping/phase rotation, one of the second vector in the first set of second vectors may be all 1 in the vector. In some embodiments, C (a, b) may be nchoosek (a, b) . In some embodiments,

may be nchoosek (a, b) .

In some embodiments, for the reference CSI-RS resource in the second plurality of CSI-RS resources, the terminal device may determine and/or report a first set of second vectors selected from the first plurality of second vectors or from the first window. In some embodiments, a first size for the field indicating the first set of second vectors corresponding to the reference CSI-RS resource may be

or

In some embodiments, when N ₃> 19. For example, based on remapping/phase rotation, one of the second vector in the first set of second vectors may be all 1 in the vector.

In some embodiments, the remapping/phase rotation may be applied to each second vector corresponding to all CSI-RS resources in the second plurality of CSI-RS resources.

In some embodiments, for the reference CSI-RS resource, the index may be represented as t _ref. In some embodiments, t _ref may be a positive integer, 1≤t _ref≤ N _TRP. In some embodiments, t _ref may be a non-negative integer, 0≤t _ref≤N _TRP-1. In some embodiments, t _ref may be at least one of {0, 1, 2, 3} or {1, 2, 3, 4} . In some embodiments, for each one of the remaining CSI-RS resources (except the reference CSI-RS resource) in the first plurality of CSI-RS resources or in the second plurality of CSI-RS resources, the index may be represented as t, and t≠t _ref. In some embodiments, t may be a positive integer, 1≤t≤N _TRP. In some embodiments, t may be a non-negative integer, 0≤t≤N _TRP-1. In some embodiments, t may be at least one of {0, 1, 2, 3} or {1, 2, 3, 4} .

In some embodiments, for each one of remaining CSI-RS resources t (except the reference CSI-RS resource) , the terminal device may determine and/or report a second offset for second vectors (For example, represented as M _initial, t) . In some embodiments, M _initial, t may be an integer. In some embodiments, the number of candidate values for M _initial, t may be N ₃ or floor (N ₃/A) or ceil (N ₃/A) . In some embodiments, 0≤M _initial, t≤N ₃-1. In some embodiments, B≤M _initial, t≤C. In some embodiments, B may be an integer. For example,

or

or B=0. In some embodiments, C may be an integer. For example,

or

or C=2M _v-1. In some embodiments, A may be 2 or 3 or 4 or

or

In some embodiments, M _initial, t∈ {0, 1, 2, …, N ₃-1} or

or

1} or

or

or M _initial, t∈ {0, 1, 2, …, 2Mv-1} or M _initial, t∈ {0, 1, 2, …, 2Mv} or M _initial, t∈ {0, A, 2A, …, xA} . In some embodiments, wherein x may be

or

In some embodiments, t≠t _ref, and t _ref may be the index of reference CSI-RS resource. For example,

In some embodiments, for each one of remaining CSI-RS resources t (except the reference CSI-RS resource) , the terminal device may determine a second plurality of second vectors (For example, a second window for the second vectors) . In some embodiments, the second plurality of second vectors or the second window for the CSI-RS resource t may be determined based on the second offset for second vectors and/or a second vector with a first index. In some embodiments, the second vector with the first index may be represented as F _υ, ref. In some embodiments, the second vector with the first index may correspond to the reference CSI-RS resource. In some embodiments, the second vector with the first index may be at least one of: the first one of second vector in the first set of second vectors corresponding to the reference CSI-RS resource, the last one of second vector in the first set of second vectors corresponding to the reference CSI-RS resource, the one of second vector corresponding to the strongest coefficient indication in the first set of second vectors corresponding to the reference CSI-RS resource, the first one of second vector in the first plurality of second vectors or from the first window corresponding to the reference CSI-RS resource and the last one of second vector in the first plurality of second vectors or from the first window corresponding to the reference CSI-RS resource. In some embodiments, F _υ, ref may be an integer. For example, F _v, ref∈ {0, 1, 2, …, N ₃-1} or F _v, ref∈ {-2M _υ+1, -2M _υ+2, …, 0, 1, 2, …, 2M _υ-2, 2M _υ-1} or F _v, ref∈ {-2M _υ+1, -2M _υ+2, …, 0, 1, 2, …, 2M _υ-2, 2M _υ} .

In some embodiments, for the reference CSI-RS resource in the second plurality of CSI-RS resources, the number of vectors in the first plurality of second vectors or the size of the first window may be 2M _υ. In some embodiments, for each one of remaining CSI-RS resources t (except the reference CSI-RS resource) , the number of vectors in the second plurality of second vectors or the size of the second window may be 2M _υ or M _υ, t or 2M _υ, t. In some embodiments, M _υ, t may be a positive integer. For example, 1≤M _υ, t≤2M _υ. For example, 1≤M _υ, t≤M _υ.

In some embodiments, for each one of remaining CSI-RS resources t (except the reference CSI-RS resource) , the first or starting one of the second vector in the second plurality of second vectors or in the second window may be F _s, t= (F _v, ref+M _offset, _t) mod N ₃ or F _s, t= (F _v, ref+ {0, 1, 2, …, 2Mv} ) mod N ₃. In some embodiments, the second plurality of second vectors or the second window may be a plurality of second vectors with index {M _initial, t, (M _initial, t+1) mod N ₃, (M _initial, t+2) mod N ₃, …, (M _initial, t+2M _υ-1) mod N ₃, (M _initial, t+2M _υ) mod N ₃} or {F _s, t, F _s, t+1, F _s, t+2, …F _s, t+M _υ, t} or {F _s, t, F _s, t+1, F _s, t+2, …F _s, t+2M _υ, t} or {F _s, t, F _s, t+1, F _s, t+2, …F _s, t+M _υ, t-1} or {F _s, t, F _s, t+1, F _s, t+2, …F _s, t+2M _υ, t-1} .

In some embodiments, for each one of remaining CSI-RS resources t (except the reference CSI-RS resource) , the second vector F _s, t may be included in the second set of second vectors corresponding to the CSI-RS resource t. For example, the field indicating the second set of second vectors corresponding to the CSI-RS resource t doesn’t need to include the indication of the second vector F _s, t. In some embodiments, a size for the field size indicating the second set of second vectors corresponding to the CSI-RS resource t may be at least one of

or

In some embodiments, the number of second vectors in the second set of second vectors corresponding to the CSI-RS resource t may be M _v or 2M _v.

In some embodiments, the number of second vectors in the first set of second vectors corresponding to the reference CSI-RS resource and/or the number of second vectors in the first set of second vectors corresponding to the CSI-RS resource t may be indicated or reported by the terminal device. In some embodiments, the number of second vectors in the first set of second vectors corresponding to the reference CSI-RS resource and/or the number of second vectors in the first set of second vectors corresponding to the CSI-RS resource t may be in CSI part 1 or in CSI part 2. In some embodiments, the number of second vectors in the first set of second vectors corresponding to the reference CSI-RS resource may not needed to be reported. In some embodiments, a field size for the number of second vectors in the first set of second vectors corresponding to the reference CSI-RS resource may be

h may be a positive integer. In some embodiments, a field size for the number of second vectors in the second set of second vectors corresponding to the CSI-RS resource t may be

ht may be a positive integer.

In some embodiments, for each one of remaining CSI-RS resources t (except the reference CSI-RS resource) , the terminal device may determine and/or report a second set of second vectors selected from the group or the whole set of N ₃ second vectors. In some embodiments, a second size for the field indicating the second set of second vectors corresponding to the CSI-RS resource t may be

or

In some embodiments, when N ₃≤ 19. For example, based on remapping/phase rotation for the reference CSI-RS resource, the remapping/phase rotation is applied to the second vectors in the second set of second vectors corresponding to the CSI-RS resource t.

In some embodiments, for each one of remaining CSI-RS resources t (except the reference CSI-RS resource) , the terminal device may determine and/or report a second set of second vectors selected from the second plurality of second vectors or from the second window. In some embodiments, a second size for the field indicating the second set of second vectors corresponding to the CSI-RS resource t may be

In some embodiments, when N ₃> 19. For example, based on remapping/phase rotation for the reference CSI-RS resource, the remapping/phase rotation is applied to the second vectors in the second set of second vectors corresponding to the CSI-RS resource t. In some embodiments, a first size for the field indicating the first set of second vectors corresponding to the reference CSI-RS resource may be

In some embodiments, the terminal device may receive the reference signal based on the number of antenna ports for the reference signal. In some embodiments, the reference signal may be at least one of: a channel state information reference signal (CSI-RS) , a sounding reference signal (SRS) , a demodulation reference signal (DMRS) , a CSI-RS for tracking and a phase tracking reference signal (PTRS) .

In some embodiments, a value of the first parameter of antenna port configuration may be represented as N ₁. For example, N ₁ may be a positive integer. For example, N ₁ may be one of {2, 3, 4, 6, 8, 12, 16} . In some embodiments, a value of the second parameter of antenna port configuration may be represented as N ₂. For example, N ₂ may be a positive integer. For example, N ₂ may be one of {1, 2, 3, 4} . In some embodiments, the first parameter of antenna port configuration and the second parameter of antenna port configuration may be configured in one higher layer parameter.

In some embodiments, the number of antenna ports for each CSI-RS resource in the first or second plurality of CSI-RS resources may be determined based on the first parameter of antenna port configuration and a second parameter of antenna port configuration. In some embodiments, the number of antenna ports for the CSI-RS resource may be P=N ₁·N ₂·2.

In some embodiments, there may be a parameter “O ₁” , and “O ₁” may represent a first discrete fourier transform (DFT) oversampling in the first dimension. For example, “O ₁” may be one of {1, 2, 4} . For another example, “O ₁” may be 2 or 4. In some embodiments, there may be a parameter “O ₂” , and “O ₂” may represent a second DFT oversampling in the second dimension. For example, “O ₂” may be one of {1, 2, 4} . For another example, “O ₂” may be 2 or 4.

In some embodiments, one configuration of (N ₁, N ₂) may correspond to one configuration of (O ₁, O ₂) . In some embodiments, one configuration of (O ₁, O ₂) may correspond to one configuration of (N ₁, N ₂) . In some embodiments, the example configurations of (N ₁, N ₂) and (O ₁, O ₂) may be at least one of row and/or column in Table 4.

Table 4. Supported configurations of (N ₁, N ₂) and (O ₁, O ₂)

In some embodiments, there may be a vector u _m. In some embodiments, u _m may be a DFT vector. In some embodiments, if N ₂>1,

In some embodiments, if N ₂=2,

In some embodiments, if N ₂=1, u _m=1. In some embodiments, m may be a non-negative integer. For example, 0≤m≤O ₂N ₂. For another example, m may be one of {0, 2, 4, 6, 8} . For another example, m may be one of {0, 1, 2, 3} . For another example, m may be 0 or 1. For another example, m may be 0. In some embodiments, there may be a vector v _l, m. In some embodiments,

In some embodiments, if N ₁=2 and N ₂=2,

In some embodiments, if N ₁=4 and N ₂=1,

In some embodiments, l may be a non-negative integer. For example, 0≤l≤O ₁N ₁. For another example, l may be one of {0, 2, 4, 6, 8} . For another example, l may be one of {0, 1, 2, 3} . For another example, l may be 0 or 1. In some embodiments, [] ^T may represent a transposition of a vector or a matrix.

In some embodiments, the terminal device may determine or report a number of layers and at least one codebook indicator based on the at least one configuration to the network device. In some embodiments, the number of layers (e.g. represented as v _ri) may be one of {1, 2} or {1, 2, 3, 4} or {1, 2, 3, 4, 5, 6, 7, 8} . In some embodiments, there may be a plurality of layers, and each layer may be with an index, wherein the index of a layer may be represented as r, r may be non-negative integer. For example, 1≤r≤v _ri. For example, r may be one of {1, 2, …v _ri} or {1, 2} or {1, 2, 3, 4} or {1, 2, 3, 4, 5, 6, 7, 8} .

In some embodiments, the at least one codebook indicator may comprise at least one of: one or more indicators (or a field) for a first plurality of antenna port groups, one or more indicators (or a field) for a second plurality of antenna port groups, one or more indicators (or a field) for a plurality of first vectors, one or more indicators (or one or more fields) for a plurality of second vectors, one or more indicators (or a field) for a first plurality of rotations for the plurality of first vectors, one or more indicators (or one or more fields) for a second plurality of rotations for the plurality of second vectors, one or more indicators (or a field) for a plurality of third vectors, one or more indicators (or a field) for a plurality of third vectors corresponding to one TRP index (or a CSI-RS resource index or an index of a group of CSI-RS ports or a CSI-RS allocation index) , an indicator (or a field) for a strongest coefficient, one or more indicators (or one or more indexes or one or more fields) for a first antenna port group, one or more indicators (or a field) for a plurality of first amplitude coefficients, one or more indicators (or a field) for a plurality of first phase coefficients, one or more indicators (or a field) for a plurality of second amplitude coefficients, one or more indicators (or a field) for a plurality of second phase coefficients, one or more indicators (or a field) for a plurality of third amplitude coefficients, one or more indicators (or a field) for a plurality of third phase coefficients, a first number of nonzero coefficients, one or more indicators (or one or more bitmaps) for indicating nonzero coefficients.

In some embodiments, the one or more indicators (or one or more bitmaps) for indicating nonzero coefficients may indicate indexes of third amplitude coefficients and/or indicating indexes of third phase coefficients, and values of the third amplitude coefficients corresponding to the indexes and/or the third phase coefficients corresponding to the indexes may be nonzero. In some embodiments, the one or more indicators (or one or more bitmaps) for indicating nonzero coefficients may indicate which coefficients in the one or more indications or in the field for the plurality of third amplitude coefficients are nonzero or reported. In some embodiments, the one or more indicators (or one or more bitmaps) for indicating nonzero coefficients may indicate which coefficients in the one or more indications or in the field for the plurality of third phase coefficients are nonzero or reported.

In some embodiments, the number of the plurality of first vectors, the second parameter for codebook and the third parameter for codebook may be configured or indicated in one higher layer parameter. In some embodiments, the fifth parameter for codebook and the sixth parameter for codebook may be configured or indicated in one higher layer parameter.

In some embodiments, the first parameter for codebook may be same with the fourth parameter for codebook. In some embodiments, the second parameter for codebook may be same with the fifth parameter for codebook. In some embodiments, the third parameter for codebook may be same with the sixth parameter for codebook.

In some embodiments, the second parameter for codebook may be at least one of {1/2, 1/4, 1/8, 1/16} . In some embodiments, the third parameter for codebook may be one of {1/4, 1/2, 3/4, 1/8, 3/8, 1} . In some embodiments, the number of the plurality of first vectors (e.g. represented as L) may be one of {2, 4, 6} or at least one of {2, 4, 6, 8, 12, 16, 24, 32} . In some embodiments, L may be a positive integer. In some embodiments, L may be one of {2, 4, 6} or one of {2, 4, 6, 8, 12, 16, 24, 32} . In some embodiments, the number of the plurality of first vectors (e.g. represented as L _t) may be one of {2, 4, 6} or at least one of {2, 4, 6, 8} . In some embodiments, L _t may be a positive integer. In some embodiments, L _t may be one of {2, 4, 6} .

In some embodiments, the third parameter for codebook may further be based on number of layers. In some embodiments, one higher layer parameter may indicate L=2 and β=1/4, and if number of layers is 1 or 2, p _v=1/4, and if number of layers is 3 or 4, p _v=1/8. In some embodiments, one higher layer parameter may indicate L=2 and β=1/2, and if number of layers is 1 or 2, p _v=1/4, and if number of layers is 3 or 4, p _v=1/8. In some embodiments, one higher layer parameter may indicate L=4 and β=1/4, and if number of layers is 1 or 2, p _v=1/4, and if number of layers is 3 or 4, p _v=1/8. In some embodiments, one higher layer parameter may indicate L=4 and β=1/2, and if number of layers is 1 or 2, p _v=1/4, and if number of layers is 3 or 4, p _v=1/8. In some embodiments, one higher layer parameter may indicate L=4 and β=3/4, and p _v=1/4. In some embodiments, one higher layer parameter may indicate L=4 and β=1/2, and if number of layers is 1 or 2, p _v=1/2, and if number of layers is 3 or 4, p _v=1/4. In some embodiments, one higher layer parameter may indicate L=6 and β=1/2, and p _v=1/4. For example, the number of layers is 1 or 2. In some embodiments, one higher layer parameter may indicate L=6 and β=3/4, and p _v=1/4. For example, the number of layers is 1 or 2.

In some embodiments, one higher layer parameter may indicate L _t=2 and β=1/4, and if number of layers is 1 or 2, p _v=1/4, and if number of layers is 3 or 4, p _v=1/8. In some embodiments, one higher layer parameter may indicate L _t=2 and β=1/2, and if number of layers is 1 or 2, p _v=1/4, and if number of layers is 3 or 4, p _v=1/8. In some embodiments, one higher layer parameter may indicate L _t=4 and β=1/4, and if number of layers is 1 or 2, p _v=1/4, and if number of layers is 3 or 4, p _v=1/8. In some embodiments, one higher layer parameter may indicate L _t=4 and β=1/2, and if number of layers is 1 or 2, p _v=1/4, and if number of layers is 3 or 4, p _v=1/8. In some embodiments, one higher layer parameter may indicate L _t=4 and β=3/4, and p _v=1/4. In some embodiments, one higher layer parameter may indicate L _t=4 and β=1/2, and if number of layers is 1 or 2, p _v=1/2, and if number of layers is 3 or 4, p _v=1/4. In some embodiments, one higher layer parameter may indicate L _t=6 and β=1/2, and p _v=1/4. For example, the number of layers is 1 or 2. In some embodiments, one higher layer parameter may indicate L _t=6 and β=3/4, and p _v=1/4. For example, the number of layers is 1 or 2.

In some embodiments, the first parameter for codebook (for example, represented as R) may be a positive integer. For example, R may be a positive integer. For example, R may be one of {1, 2} . In some embodiments, a number of precoding matrices may be determined based on the first parameter for codebook, the number of the plurality of first subbands. In some embodiments, the first parameter for codebook may control the total number of precoding matrices indicated by the PMI as a function of the number of configured first subbands or the number of the plurality of first subbands, the size of one first subband and of the number of PRBs for the BWP. In some embodiments, if the second plurality of CSI-RS resources includes only one CSI-RS resource, the value of R may be either 1 or 2. In some embodiments, if the second plurality of CSI-RS resources includes more than one CSI-RS resource, the value of R may be 1.

In some embodiments, second subband may correspond to a subband for precoding matrix indicator (PMI) or PMI subband.

In some embodiments, the size of one second subband or the number of PRBs of one second subband may be represented as N _PMI, and N _PMI is a positive integer. For example, 1≤N _PMI≤32. For example, N _PMI may be one of {2, 4, 8, 16, 32} . In some embodiments, N _PMI may be based on

and R. For example,

In some embodiments, the number of the plurality of second subbands N ₃ or the size or the length of one second vector may be a positive integer. For example, 9≤N ₃≤36. For example,

For another example,

In some embodiments, when R=1, there may be one precoding matrix indicated for each first subband. In some embodiments, when R=2, for one first subband that is not the first/beginning one or the last/ending one of the plurality of first subbands in the BWP, there may be two precoding matrixes indicated for the one of the plurality of first subbands. For example, the first precoding matrix corresponds to the first

PRBs of the one of the plurality of first subbands, and the second precoding matrix corresponds to the last

PRBs of the one of the plurality of first subbands. In some embodiments, when R=2, for one first subband that is the first/beginning one or the last/ending one of the plurality of first subbands in the BWP, if

there may be one precoding matrix indicated corresponding to the first/beginning one of the plurality of first subbands.

In some embodiments, when R=2, for one first subband that is the first/beginning one or the last/ending one of the plurality of first subbands in the BWP, if

there may be two precoding matrices indicated corresponding to the first/beginning one of the plurality of first subbands. For example, the first precoding matrix may correspond to the first

PRBs of the first/beginning one of the plurality of first subbands and the second precoding matrix corresponds to the last

PRBs of the first/beginning one of the plurality of first subbands.

there may be one precoding matrix indicated corresponding to the last/ending one of the plurality of first subbands.

In some embodiments, when R=2, for one first subband that is the first/beginning one or the last/ending one of the plurality of first subbands, if

there may be two precoding matrices indicated corresponding to the last/ending one of the plurality of first subbands. For example, the first precoding matrix may correspond to the first

PRBs of the last/ending one of the plurality of first subbands and the second precoding matrix may correspond to the last

PRBs of the last/ending one of the plurality of first subbands.

In some embodiments, the number of the plurality of second vectors M _υ may be a positive integer. For example,

For example, M _υ may be one of {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} .

In some embodiments, a plurality of precoding matrices may be determined from L+M _υ vectors or L _t+M _υ vectors or N _TRP· (L _t+M _υ) vectors or N _TRP·L _t+M _υ vectors.

In some embodiments, nchoosek may be a function to choose k values from n values. In some embodiments, nchoosek (a, b) = a! / (b! * (a-b) ! ) . In some embodiments, “! ” may be factorial. In some embodiments, a! = 1*2*…* (a-1) *a.

In some embodiments, the one or more indicators (or the field) for the second plurality of antenna port groups may be comprised in the CSI or in the first part of the CSI.

In some embodiments, a number of the one or more indicators (or one or more indexes or one or more fields) for a first antenna port group may be same as the number of layers. In some embodiments, the number of the one or more indicators (or one or more indexes or one or more fields) for a first antenna port group may be 1. For example, common for each layer of the number of layers. In some embodiments, the one or more indicators (or one or more indexes or one or more fields) for a first antenna port group may be same for each layer of the number of layers.

In some embodiments, one first vector of the plurality of first vectors may be represented as

In some embodiments,

In some embodiments,

In some embodiments, i=0, 1, …L _t-1. In some embodiments, t=0, 1, …N _TRP-1. In some embodiments, t=0, 1, …N-1. In some embodiments, T ₁=N _TRP. In some embodiments, T=N _TRP. In some embodiments, T _s=N.

In some embodiments, q _1, t and q _2, t may be rotations of the second plurality of rotations for the plurality of first vectors. For example, the q _1, t and q _2, t may be the rotations corresponding to antenna port group with index t. In some embodiments, q _1, t∈ {0, 1, …O ₁-1} . In some embodiments, q _2, t∈ {0, 1, …O ₂-1} . In some embodiments, for the second plurality of CSI-RS resources, there may be N fields for indication of the rotations, and each field indicating the rotations corresponding to one CSI-RS resource in the second plurality of CSI-RS resources. In some embodiments, for the second plurality of CSI-RS resources, there may be one field for indication of the rotations, and the field indicating common rotations corresponding to each CSI-RS resource in the second plurality of CSI-RS resources.

In some embodiments, the number of one or more indicators (or the field) for the plurality of first amplitude coefficients may be K _b1* (T-1) or K _b1* (T ₁-1) or K _b1* (T _s-1) or

In some embodiments, K _b1 may be the bit size for each of the first amplitude coefficients. For example, K _b1 may be 2 or 3 or 4 bits.

In some embodiments, the number of one or more indicators (or the field) for the plurality of first amplitude coefficients may be K _b1* (T-1) *M _w or K _b1* (T ₁-1) *M _w or K _b1* (T _s-1) *M _w or

In some embodiments, the one or more indicators (or the field) for the plurality of first amplitude coefficients may be comprised in the PMI or in the first part of the PMI or in the second part of the PMI.

In some embodiments, the number of one or more indicators (or the field) for the plurality of first phase coefficients may be based on the number of the first plurality of antenna port groups or the number of the second plurality of antenna port groups. In some embodiments, the number of one or more indicators (or the field) for the plurality of first phase coefficients may be based on the number of the first plurality of antenna port groups minus 1 or the number of the second plurality of antenna port groups minus 1.

In some embodiments, the number of one or more indicators (or the field) for the plurality of first phase coefficients may be K _b2* (T-1) or K _b2* (T ₁-1) or K _b2* (T _s-1) or

In some embodiments, K _b2 may be the bit size for each of the first phase coefficients. For example, K _b2 may be 2 or 3 or 4 bits.

In some embodiments, the number of one or more indicators (or the field) for the plurality of first phase coefficients may be K _b2* (T-1) *M _w or K _b2* (T ₁-1) *M _w or K _b2* (T _s-1) *M _w or

In some embodiments, one first vector may be represented as v _i,

In some embodiments,

may be a first amplitude coefficient for antenna port group with index t. In some embodiments,

may be a first phase coefficient for antenna port group with index t.

In some embodiments, T may be based on the number of first plurality of antenna port groups T ₁. In some embodiments, T=T ₁. In some embodiments, T may be based on the number of second plurality of antenna port groups T _s. In some embodiments, T=T _s.

In some embodiments,

wherein

For example, size of W ₁ may be (2*N ₁*N ₂*T) * (2*L _t) or (2*N ₁*N ₂*T _s) * (2*L _t) . For example, a size of each element in W ₁ may be (N ₁*N ₂*T) *L _t, “0” in W ₁ may be a zero matrix with size (N ₁*N ₂*T) *L _t.

In some embodiments,

In some embodiments, W ₁=W ₀₁*W ₀₂.

In some embodiments,

In some embodiments, the size of W ₀₁ may be (2*N ₁*N ₂) * (2*L _t) .

In some embodiments,

In some embodiments,

In some embodiments, for W2 corresponding to layer with index r:

In some embodiments, f may be an index of one sedond vector. For example, f=0, 1, …M _v-1.

In some embodiments,

may be the second amplitude coefficient corresponding to layer with index r. In some embodiments,

may not be needed. In some embodiments,

may be fixed to be 1.

In some embodiments,

may be third amplitude coefficient corresponding to the layer with index r and corresponding to one first vector with index i and corresponding to second vector with index f.

In some embodiments,

may be third amplitude coefficient corresponding to the layer with index r and corresponding to a first vector with index i and corresponding to second vector with index f.

In some embodiments, s may be 0 and/or 1. For example, s may be for two polarizations. In some embodiment, s may be for different groups of vectors.

In some embodiments, for second vectors (e.g. represented as W _f) corresponding to layer with index r,

In some embodiments, the size of W _f may be M _v*N ₃.

In some embodiments,

In some embodiments, z may be an index of a second subband. For example, z= {0, 1, …N ₃-1}

In some embodiments, for the codebook corresponding to layer with index r and second subband with index z,

In some embodiments, γ _z, r may be a variant for power calculation or power normalization.

In some embodiments, γ _z, r may be based on the plurality of third amplitude coefficients, the plurality of third phase coefficients and at least one of: the plurality of first amplitude coefficients, the plurality of second amplitude coefficients, the plurality of first phase coefficients and the plurality of second phase coefficients. In some embodiments, γ _z, r may be based on at least one of: the number of the plurality of first vectors, the number of the plurality of second vectors and the number of the plurality of third vectors.

In some embodiments,

In some embodiments, for bits or codepoints or values of the one or more indicators (or one or more bitmaps) for indicating nonzero coefficients with value to be 0, the third amplitude coefficient and/or the third phase coefficient corresponding to the bits or codepoints or values may be set to 0.

In some embodiments, the number of the plurality of first vectors may be based on the number of CSI-RS resources in the second plurality of CSI-RS resources.

In some embodiments,

In some embodiments,

In some embodiments, corresponding to a layer with index r,

In some embodiments,

may be the first amplitude coefficient for antenna port group with index t. In some embodiments,

may not be needed. In some embodiments,

may be fixed to be 1.

In some embodiments,

may be the first phase coefficient for antenna port group with index t. In some embodiments,

may not be needed. In some embodiments,

may be fixed to be 1.

In some embodiments,

may be the second amplitude coefficient corresponding to antenna port group with index t and corresponding to layer with index r. In some embodiments,

may not be needed. In some embodiments,

may be fixed to be 1.

In some embodiments,

may be third amplitude coefficient for antenna port group with index t and corresponding to the layer with index r and corresponding to one first vector with index i and corresponding to second vector with index f.

In some embodiments,

may be third amplitude coefficient for antenna port group with index t and corresponding to the layer with index r and corresponding to a first vector with index i and corresponding to second vector with index f.

In some embodiments, the size of W _f may be M _v*N ₃.

In some embodiments,

In some embodiments, a value of one first amplitude coefficient may be one of

In some embodiments, the bit size for one first amplitude coefficient may be 4 bits. In some embodiments, a value of an indicator or a field for one first amplitude coefficient may be one of {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15} .

In some embodiments, an indicator or a field for one first amplitude coefficient with value 0 may correspond to the first amplitude coefficient with value 0. In some embodiments, an indicator or a field for one first amplitude coefficient with value 1 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 2 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 3 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 4 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 5 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 6 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 7 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 8 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 9 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 10 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 11 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 12 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 13 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 14 may correspond to the first amplitude coefficient with value

In some embodiments, an indicator or a field for one first amplitude coefficient with value 15 may correspond to the first amplitude coefficient with value 1.

In some embodiments, a value of one first amplitude coefficient may be one of

In some embodiments, the bit size for one first amplitude coefficient may be 4 bits. In some embodiments, a value of an indicator or a field for one first amplitude coefficient may be one of {0, 1, 2, 3, 4, 5, 6, 7} .

In some embodiments, an indicator or a field for one first amplitude coefficient with value 7 may correspond to the first amplitude coefficient with value 1.

In some embodiments, the value of the first amplitude coefficient corresponding to the first antenna port group (for example, the antenna port group with index T _m) may be 1. In some embodiments, the value of the indicator or the field for the first amplitude coefficient corresponding to the first antenna port group (for example, the antenna port group with index T _m) may be 15. In some embodiments, the value of the first amplitude coefficient or the indicator or the field for the first amplitude coefficient corresponding to the first antenna port group (for example, the antenna port group with index T _m) may not be reported in the PMI.

In some embodiments, the value of the first amplitude coefficient corresponding to the antenna port group which is not included in the second plurality of antenna port groups may be 0. In some embodiments, the value of the indicator or the field for the first amplitude coefficient corresponding to the antenna port group which is not included in the second plurality of antenna port groups may be 0. In some embodiments, the value of the first amplitude coefficient or the indicator or the field for the first amplitude coefficient corresponding to the antenna port group which is not included in the second plurality of antenna port groups may not be reported in the PMI.

In some embodiments, a value of one second amplitude coefficient may be one of

In some embodiments, the bit size for one second amplitude coefficient may be 4 bits. In some embodiments, a value of an indicator or a field for one second amplitude coefficient may be one of {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15} .

In some embodiments, an indicator or a field for one second amplitude coefficient with value 0 may correspond to the second amplitude coefficient with value 0. In some embodiments, an indicator or a field for one second amplitude coefficient with value 1 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 2 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 3 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 4 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 5 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 6 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 7 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 8 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 9 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 10 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 11 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 12 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 13 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 14 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 15 may correspond to the second amplitude coefficient with value 1.

In some embodiments, a value of one second amplitude coefficient may be one of

In some embodiments, the bit size for one second amplitude coefficient may be 4 bits. In some embodiments, a value of an indicator or a field for one second amplitude coefficient may be one of {0, 1, 2, 3, 4, 5, 6, 7} .

In some embodiments, an indicator or a field for one second amplitude coefficient with value 7 may correspond to the second amplitude coefficient with value 1.

In some embodiments, a value of one second amplitude coefficient may be one of

In some embodiments, the bit size for one second amplitude coefficient may be 3 bits. In some embodiments, a value of an indicator or a field for one second amplitude coefficient may be one of {0, 1, 2, 3, 4, 5, 6, 7} .

In some embodiments, an indicator or a field for one second amplitude coefficient with value 0 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 1 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 7 may correspond to the second amplitude coefficient with value 1. In some embodiments, one second amplitude coefficient may be a differential value corresponding to one first amplitude coefficient.

In some embodiments, a value of one second amplitude coefficient may be one of

In some embodiments, the bit size for one second amplitude coefficient may be 1 bit. In some embodiments, a value of an indicator or a field for one second amplitude coefficient may be one of {0, 1} . In some embodiments, an indicator or a field for one second amplitude coefficient with value 0 may correspond to the second amplitude coefficient with value

In some embodiments, an indicator or a field for one second amplitude coefficient with value 1 may correspond to the second amplitude coefficient with value 1. In some embodiments, one second amplitude coefficient may be a differential value corresponding to one first amplitude coefficient.

In some embodiments, the value of the second amplitude coefficient corresponding to the antenna port group which is not included in the second plurality of antenna port groups may be 0. In some embodiments, the value of the indicator or the field for the second amplitude coefficient corresponding to the antenna port group which is not included in the second plurality of antenna port groups may be 0. In some embodiments, the value of the second amplitude coefficient or the indicator or the field for the second amplitude coefficient corresponding to the antenna port group which is not included in the second plurality of antenna port groups may not be reported in the PMI.

In some embodiments, a value of one third amplitude coefficient may be one of

In some embodiments, the bit size for one third amplitude coefficient may be 3 bits. In some embodiments, a value of an indicator or a field for one third amplitude coefficient may be one of {0, 1, 2, 3, 4, 5, 6, 7} .

In some embodiments, an indicator or a field for one third amplitude coefficient with value 0 may correspond to the third amplitude coefficient with value

In some embodiments, an indicator or a field for one third amplitude coefficient with value 1 may correspond to the third amplitude coefficient with value

In some embodiments, an indicator or a field for one third amplitude coefficient with value 2 may correspond to the third amplitude coefficient with value

In some embodiments, an indicator or a field for one third amplitude coefficient with value 3 may correspond to the third amplitude coefficient with value

In some embodiments, an indicator or a field for one third amplitude coefficient with value 4 may correspond to the third amplitude coefficient with value

In some embodiments, an indicator or a field for one third amplitude coefficient with value 5 may correspond to the third amplitude coefficient with value

In some embodiments, an indicator or a field for one third amplitude coefficient with value 6 may correspond to the third amplitude coefficient with value

In some embodiments, an indicator or a field for one third amplitude coefficient with value 7 may correspond to the third amplitude coefficient with value 1. In some embodiments, one third amplitude coefficient may be a differential value corresponding to one first amplitude coefficient and/or one second amplitude coefficient.

In some embodiments, a value of one third amplitude coefficient may be one of

In some embodiments, the bit size for one third amplitude coefficient may be 1 bit. In some embodiments, a value of an indicator or a field for one third amplitude coefficient may be one of {0, 1} . In some embodiments, an indicator or a field for one third amplitude coefficient with value 0 may correspond to the third amplitude coefficient with value

In some embodiments, an indicator or a field for one third amplitude coefficient with value 1 may correspond to the third amplitude coefficient with value 1.

In some embodiments, for bits or codepoints or values of the one or more indicators (or one or more bitmaps) for indicating nonzero coefficients with value to be 0, the value of the first amplitude coefficient corresponding to the bits or codepoints or values may be set to be 0 and/or the value of an indicator or a field for the first amplitude coefficient corresponding to the bits or codepoints or values may be set to be 0. In some embodiments, the value of the first amplitude coefficient corresponding to the bits or codepoints or values and/or the value of an indicator or a field for the first amplitude coefficient corresponding to the bits or codepoints or values may not be reported in the PMI.

In some embodiments, for bits or codepoints or values of the one or more indicators (or one or more bitmaps) for indicating nonzero coefficients with value to be 0, the value of the second amplitude coefficient corresponding to the bits or codepoints or values may be set to be 0 and/or the value of an indicator or a field for the second amplitude coefficient corresponding to the bits or codepoints or values may be set to be 0. In some embodiments, the value of the second amplitude coefficient corresponding to the bits or codepoints or values and/or the value of an indicator or a field for the second amplitude coefficient corresponding to the bits or codepoints or values may not be reported in the PMI.

In some embodiments, for bits or codepoints or values of the one or more indicators (or one or more bitmaps) for indicating nonzero coefficients with value to be 0, the value of the third amplitude coefficient corresponding to the bits or codepoints or values may be set to be 0 and/or the value of an indicator or a field for the third amplitude coefficient corresponding to the bits or codepoints or values may be set to be 0. In some embodiments, the value of the third amplitude coefficient corresponding to the bits or codepoints or values and/or the value of an indicator or a field for the third amplitude coefficient corresponding to the bits or codepoints or values may not be reported in the PMI.

In some embodiments, for bits or codepoints or values of the one or more indicators (or one or more bitmaps) for indicating nonzero coefficients with value to be 0, the value of at least one of the first phase coefficient, the second phase coefficient and the third phase coefficient corresponding to the bits or codepoints or values may be set to be 0 and/or the value of an indicator or a field for at least one of the first phase coefficient, the second phase coefficient and the third phase coefficient corresponding to the bits or codepoints or values may be set to be 0. In some embodiments, the value of at least one of the first phase coefficient, the second phase coefficient and the third phase coefficient corresponding to the bits or codepoints or values and/or the value of an indicator or a field for at least one of the first phase coefficient, the second phase coefficient and the third phase coefficient corresponding to the bits or codepoints or values may not be reported in the PMI.

In some embodiments, a value of one first phase coefficient may be

In some embodiments, c _p may be a value of one indicator or one field for the first phase coefficient. In some embodiments, a value of one second phase coefficient may be

In some embodiments, c _p may be a value of one indicator or one field for the second phase coefficient. In some embodiments, a value of one third phase coefficient may be

In some embodiments, c _p may be a value of one indicator or one field for the third phase coefficient. In some embodiments, c _p may be a non-negative integer. In some embodiments, c _p may be one of {0, 1, 2, 3} or {0, 1, 2, 3, 4, 5, 6, 7} or {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15} . In some embodiments, N _PSK may be the size for indication of c _p. In some embodiments, N _PSK may be a positive integer. In some embodiments, N _PSK may be one of {2, 4, 8, 16} .

In some embodiments, K _b2 may be the bit size for each of the first phase coefficients. For example, K _b2 may be 2 (e.g. N _PSK=4) or 3 (e.g. N _PSK=8) or 4 bits (e.g. N _PSK=16) .

In some embodiments, a first vector may be after a schimidt orthogonalization based on the first vectors in this disclosure.

In some embodiments, the value of N3 corresponding to the first set of codebook indicators may be no larger than or less than the value of N3 corresponding to the second set of codebook indicators. In some embodiments, a value of the first parameter and/or a value of the fourth parameter corresponding to the first set of codebook indicators may be no larger than or less than a value of the first parameter and/or a value of the fourth parameter corresponding to the second set of codebook indicators. In some embodiments, the first value of the number of the second plurality of antenna port groups may be 1. In some embodiments, the second value of the number of the second plurality of antenna port groups may be 2 or 3 or 4. In some embodiments, the first set of codebook indicators may be single-TRP hypothesis. In some embodiments, the second set of codebook indicators may be multi-TRP hypothesis.

In some embodiments, the bit size of the one or more indicators or fields for the plurality of third amplitude coefficients and/or the bit size of the one or more indicators or fields for the plurality of third phase coefficients corresponding to the first set of codebook indicators may be less than the bit size of the one or more indicators or fields for the plurality of third amplitude coefficients and/or the bit size of the one or more indicators or fields for the plurality of third phase coefficients corresponding to the second set of codebook indicators.

In some embodiments, the bit size of the one or more indicators for the plurality of first vectors and/or the bit size of the one or more indicators for the plurality of first vectors may be based on ceil (log2 (nchoosek (N ₁N ₂, L) ) ) or ceil (log2 (nchoosek (N ₁N ₂, L _t*T) ) ) or ceil (log2 (nchoosek (N ₁N ₂, L _t*T ₁) ) ) or ceil (log2 (nchoosek (N ₁N ₂, L _t*T _s) ) ) .

For ease of discussion, some terms used in the following description are listed as below:

● An omission priority: a priority for controlling dropping or omitting. Specifically, different partitions/information groups in the CSI feedback may be configured with different omission priorities. In case that the transmission resource is insufficient, the partition (s) /information group (s) (including the related parameters) with lower omission priority (ies) would be dropped or omitted first.

● A CSI-RS allocation: refers to a CSI-RS unit, a CSI-RS resource, a group of CSI-RS resources, or a group of CSI-RS ports. In some embodiments, one CSI-RS allocation may correspond to a TRP.

● A first CSI-RS allocation: refers to a specific CSI-RS allocation, such as a CSI-RS allocation corresponding to a primary TRP, a TRP with index value of 0, a TRP with strongest amplitude coefficient, or a TRP with the maximum power.

● A first TRP: refers to a specific TRP, such as, a primary TRP, a TRP with index value of 0, a TRP with strongest amplitude coefficient, or a TRP with the maximum power.

● A first group of CSI-RS ports: refers to a specific group of CSI-RS ports, such as a group of CSI-RS ports corresponding to a first CSI-RS allocation, a primary TRP, a TRP with index value of 0, a TRP with strongest amplitude coefficient, or a TRP with the maximum power.

In the context of the present application, the terms “TCI state” , “set of QCL parameter (s) ” , “QCL parameter (s) ” , “QCL assumption” and “QCL configuration” can be used interchangeably. The terms “TCI field” , “TCI state field” , and “transmission configuration indication” can be used interchangeably.

The terms “precoding matrix” , “precoding” , “beam” , “beamforming” , “vector” , “first vector” , “first basis” , “first basis vector” and “precoder” may be used interchangeably. The terms “vector” , “bases” and “basis” can be used interchangeably.

In the context of the present application, the terms “single TRP” , “single TCI state” , “single TCI” , “S-TCI” , “single CORESET” , “single control resource set pool” , “S-TRP” and “S-TCI state” can be used interchangeably.

The terms “multiple TRPs” , “multiple TCI states” , “multiple CORESETs” and “multiple control resource set pools” , “multi-TRP” , “multi-TCI state” , “multi-TCI” , “multi-CORESET” and “multi-control resource set pool” , “MTRP” and “M-TCI” , “M-TPR” can be used interchangeably.

In the context of the present application, the terms “pool” , “set” , “subset” , “group” , “unit” and “subgroup” can be used interchangeably.

In the context of the present application, the terms “index” , “indicator” , “indication” , “field” , “bit field” and “bitmap” can be used interchangeably. The terms “physical resource block” , “resource block” , “PRB” and “RB” can be used interchangeably. The terms “bit size” , “size of bits” , “number of bits” , “size of field” and “field size” can be used interchangeably.

In the context of the present application, the terms “first vector” , “first beam” , “first bases” , “spatial domain/SD basis vectors” , “spatial domain/SD vectors” , “spatial domain/SD basis” , “spatial domain/SD bases” and “first basis” can be used interchangeably.

In the context of the present application, the terms “first vector” , “first beam” , “beam” , “first bases” , “first basis vector” , “spatial domain/SD basis vector” , “spatial domain/SD basis vectors corresponding to a TRP index” , “spatial domain/SD vectors corresponding to a TRP index” , “spatial domain/SD basis corresponding to a TRP index” , “spatial domain/SD bases corresponding to a TRP index” , “first basis corresponding to a TRP index” , “doppler domain/DD basis vector” , “doppler domain/DD vector” , “doppler domain/DD basis” and “first basis” can be used interchangeably.

In the context of the present application, the terms “second vector” , “second basis” , “frequency domain/FD basis vector” , “frequency domain/FD vector” , “frequency domain/FD basis” , “frequency domain/FD bases” , “second bases” , “second vector corresponding to a TRP index” , “second bases corresponding to a TRP index” , “frequency domain/FD basis vectors corresponding to a TRP index” , “frequency domain/FD vectors corresponding to a TRP index” , “frequency domain/FD basis corresponding to a TRP index” , “frequency domain/FD bases corresponding to a TRP index” , “doppler domain/DD basis vector” , “doppler domain/DD vector” , “doppler domain/DD basis” , and “second basis corresponding to a TRP index” can be used interchangeably.

In the context of the present application, the terms “third vector” , “third bases” , “doppler domain/DD basis vectors” , “doppler domain/DD vectors” , “doppler domain/DD basis” , “doppler domain/DD bases” , “third basis” , “third vector corresponding to a TRP index” , “third bases corresponding to a TRP index” , “doppler domain/DD basis vectors corresponding to a TRP index” , “doppler domain/DD vectors corresponding to a TRP index” , “doppler domain/DD basis corresponding to a TRP index” , “doppler domain/DD bases corresponding to a TRP index” , and “third basis corresponding to a TRP index” can be used interchangeably. In the context of the present application, the terms “doppler domain” , “time domain” , “TD” and “DD” can be used interchangeably. In the context of the present application, the terms “a TRP” , “a TRP group” , “a CSI-RS resource” and “a group of CSI-RS ports” can be used interchangeably.

In the context of the present application, the embodiments described for the first vector may be applied for the second vector and/or for the third vector and/or for the FD basis vector or for the SD basis vector or for the DD basis vector. In the context of the present application, the embodiments described for the second vector may be applied for the first vector and/or for the third vector and/or for the FD basis vector or for the SD basis vector or for the DD basis vector.

In the context of the present application, the terms “a TRP index” , “a TRP group index” , “a CSI-RS resource index” and “a group of CSI-RS ports index” can be used interchangeably.

In the context of the present application, the terms “element of indication field” , “parameter” , “indication” can be used interchangeably.

Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

FIG. 2A shows an example communication environment 200 in which example embodiments of the present disclosure can be implemented.

The communication environment 200 includes a network device 210-1 and a terminal device 220, and further the network device 210-1 can communicate with the terminal device 220 via physical communication channels or links. Additionally, the network device 210-1 may provide more than one serving area.

Optionally, in some embodiments, the communication environment 200 also comprises another network device 210-2, which also may communicate with the terminal device 220. For purpose of discussion, the network devices 210-1 and 210-2 are collectively or individually referred to as network device 210, respectively.

In the specific example of communication environment 200, a link from the terminal device 220 to the network device 210-1 is referred to as uplink, while a link from the network device 210-1 to the terminal device 220 is referred to as a downlink. Further, the MIMO is supported in the communication environment 200, such that the network device 210-1 and the terminal device 220 may communicate with each other via different beams to enable a directional communication. In downlink, the network device 210-1 is a transmitting (TX) device (or a transmitter) and the terminal device 220 is a receiving (RX) device (or a receiver) , and the network device 210-1 may transmit downlink transmission to the terminal device 220 via one or more beams. As illustrated in FIG. 2A, the network device 210-1 transmits downlink transmission to the terminal device 220 via the beams 240-1 to 240-3.

Correspondingly, in uplink, the network device 210-1 is a RX device (or a receiver) and the terminal device 220 is a TX device (or a transmitter) , and the terminal device 220 may transmit uplink transmission to the network device 210-1 via one or more beams. As illustrated in FIG. 2A, the terminal device 220 transmits uplink transmission to the network device 210-1 via the beams 230-1 to 230-3. For purpose of discussion, the beams 230-1 to 230-3 or beams 240-1 to 240-3 are collectively or individually referred to as beam 230 or beam 240, respectively.

In addition, the terminal device 220 may be deployed with more than one panel. As illustrated in FIG. 2A, the terminal device 220 is deployed with panels 250-1 and 250-2. In the following, the panels 250-1 and 250-2 may be referred to as the first panel 250-1 and the second panel 250-2, respectively. In some embodiments, panels 250-1 and 250-2 may correspond to different sets of capability parameters, respectively.

In some embodiments, one panel may be associated with one or more CSI-RS allocations/beams. In this way, the terminal device 220 may use a specific panel to transmit the directional signal to the network device 210-1 via specific beam (s) associated with the CSI-RS allocations.

In some embodiments, different panels correspond to different panel types/capability value sets. For example, the panels 250-1 and 250-2 may correspond to different number of SRS ports, frequency resource (frequency band, CC, beam and so on) and any other suitable capability parameters (such as, capability value sets) .

Further, in the specific example of FIG. 2A, the network device 210-1 may transmit configuration (s) for CSI feedback to the terminal device 220, and the terminal device 220 also may transmit the CSI feedback to the network device 210-1.

In some embodiments, the CSI feedback is transmitted on PUSCH. Alternatively, in some other embodiments, the CSI feedback is transmitted on PUCCH.

Further, the terminal device 220 may communicate with the network device 210 via one or more TRPs. FIG. 2B shows an example scenario of the communication network 280. In the specific example of FIG. 2B, a first TRP 285-1 and the second TRP 285-2 may be used for the communication between the terminal device 220 and the network device (s) 210.

In some embodiments, the network device 210 may communicate with the terminal device 220 via a first TRP and/or a second TRP and/or a third TRP and/or a fourth TRP. For example, the first TRP and/or the second TRP and/or the third TRP and/or the fourth TRP may be included in a same serving cell or different serving cells provided by the network device 210. Although some embodiments of the present disclosure are described with reference to the first TRP and/or the second TRP and/or the third TRP and/or the fourth TRP within same serving cell provided by the network device 210, these embodiments are only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitations as to the scope of the present disclosure. It is to be understood that the present disclosure described herein can be implemented in various manners other than the ones described below.

FIG. 2C illustrates a schematic diagram 290 of spatial domain, frequency domain and Doppler/time domain basis. As illustrated in FIG. 2C, in a plurality of codebooks or precoding matrices which comprises spatial domain, frequency domain and doppler/time domain vectors. In some embodiments, in each time point or time unit in the doppler/time domain, such as t=0, 1, 2, 3, …, N ₄-1, there is a corresponding W (t) , as illustrated in FIG. 2C. Parameter W (t) may be obtained by below equation (1) :

In some embodiments, one example of the predefined codebook structure is enabled through per-TRP (port-group or resource) SD/FD basis selection and relative co-phasing/amplitude. Example formulation (N = number of TRPs or TRP groups) is as below:

Or

In some embodiments, a further example of the predefined codebook structure is enabled through per-TRP (port-group or resource) SD basis selection and joint (across N TRPs) FD basis selection. Example formulation (N = number of TRPs or TRP groups) :

It is to be understood that the number of devices and their connections in FIG. 2A and FIG. 2B are given for the purpose of illustration without suggesting any limitations to the present disclosure. The communication environment 200 and communication network 280 may include any suitable number of network devices and/or terminal devices and/or TRPs adapted for implementing implementations of the present disclosure.

In some embodiments, the terminal device 220 and the network device 210 may communicate with each other via a channel such as a wireless communication channel on an air interface (e.g., Uu interface) . The wireless communication channel may comprise a PUCCH, a PUSCH, a physical random-access channel (PRACH) , a physical downlink control channel (PDCCH) , a PDSCH and a physical broadcast channel (PBCH) . Of course, any other suitable channels are also feasible.

The communications in the communication environment 200 and communication network 280 may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , New Radio (NR) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , Machine Type Communication (MTC) and the like. The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.

It should be understood that although feature (s) /operation (s) are discussed in specific example embodiments separately, unless clearly indicated to the contrary, these feature (s) /operation (s) described in different example embodiments may be used in any suitable combination.

In addition, in the following description, some interactions are performed among the terminal device 220 and the network device 210 (such as, exchanging configuration (s) and so on) . It is to be understood that the interactions may be implemented either in one single signaling/message or multiple signaling/messages, including system information, radio resource control (RRC) message, downlink control information (DCI) message, uplink control information (UCI) message, media access control (MAC) control element (CE) and so on. The present disclosure is not limited in this regard.

Principle and implementations of the present disclosure will be described in detail below with reference to FIG. 3, which shows a signaling chart illustrating a process 300 of communication according to some example embodiments of the present disclosure. For the purpose of discussion, the process 300 will be described with reference to FIG. 2A and FIG. 2B. The process 300 may involve the terminal device 220 and the network device 210.

In some embodiments, there may be a plurality of TRPs, for example N TRPs/TRP groups, where N is larger than 2. Further, each TRP/TRP group may be indexed by t, t∈ {0, 1, …N-1} or t∈ {1, 2, …N} ) .

In some embodiments, each TRP/TRP group corresponds to a CSI-RS allocation, such as, a CSI-RS unit, a CSI-RS resource, a group of CSI-RS resources, or a group of CSI-RS ports.

In some embodiments, a value of the first parameter of antenna port configuration may be represented as N1. For example, N1 may be a positive integer. For example, N1 may be at least one of {2, 3, 4, 6, 8, 12, 16} . In some embodiments, a value of the second parameter of antenna port configuration may be represented as N2. For example, N2 may be a positive integer. For example, N2 may be at least one of {1, 2, 3, 4} . In some embodiments, the first parameter of antenna port configuration and the second parameter of antenna port configuration may be configured in one higher layer parameter.

In some embodiments, the network device 210 may configure the terminal device 220 to report CSI feedback. As shown in FIG. 3, the terminal device 220 receives 310 from a network device, configuration (s) for the CSI feedback.

Next, the terminal device 220 transmits 330 the CSI feedback to the network device 210 based on the at least one configuration.

In some embodiments, FIG. 4 illustrates an example according to some embodiments of the present disclosure. It is to be understood that the specific structures illustrated in FIG. 4 are only for the purpose of illustration without suggesting any limitations. In other words, the numbers of windows and/or the number of FD bases may be changed. In some embodiments, there may be a first window determined or indicated. For example, the first window may be for the reference CSI-RS resource in the second plurality of CSI-RS resources. In some embodiments, there may be a second window determined or indicated. For example, the second window may be for one of remaining CSI-RS resources t (except the reference CSI-RS resource) . In some embodiments, the first one of the FD basis vector or the first one of the second vector in the second window may be assumed to be selected or may be always selected for the CSI-RS resource t (except the reference CSI-RS resource) in the second plurality of CSI-RS resources.

In some embodiments, the plurality of partitions comprises parameters associated with one or more of a plurality of CSI-RS allocations. In case that a plurality of CSI-RS allocations are available (i.e., a multi-TRP is supported) , the parameters may be transmitted according to different omission priorities, such that the priority rule for reporting the CSI parameters is updated to adaptable for the scenario where a multi-TRP is supported.

In some embodiments, the terminal device 220 determines 320 priorities and includes the parameters into the plurality of partitions of the CSI feedback based on the priorities. In some embodiments, the terminal device 220 determines a respective first priority for a CSI-RS allocation of the plurality of CSI-RS allocations. In this way, the parameters may be transmitted in a priority order of CSI-RS allocations. Alternatively, in some other embodiments, the terminal device 220 determines a respective second priority for a parameter of the parameters comprised in the CSI feedback. In this way, the dropping risk of the parameters with a higher priority may be reduced.

In some embodiments, the priorities may be determined based on one or more factors. One example factor is an index of a CSI-RS resource. Another example factor is an index of a CSI-RS resource group. A further example factor is an index of group of CSI-RS ports. The other factors, include but are not limited to, an index of an SD basis (such as, an index of an SD basis corresponding to a CSI-RS allocation) .

It is to be understood that the above examples of factors are illustrated only for the purpose of illustration without suggesting any limitations. In other example embodiments, other factors may be defined. The present disclosure is not limited in this regard.

Additionally, in some embodiments, different factors are configured with different contributions when determining the priorities. In this way, the priority rule is more flexible.

In some embodiments, CSI parameters (or a first subset of PMI fields and/or CQI) corresponding to one TRP/TRP group (represented as the first TRP/TRP group) has a higher priority than CSI parameters (or other subsets of PMI fields and/or CQI) corresponding to other TRPs (i.e., a subset of TRPs/TRP groups with the first TRP/TRP group excluded, for example, N-1 TRPs/TRP groups excluding the first TRP/TRP group) .

In some embodiments, for given CSI feedback (such as, a CSI report #n) , each reported element of indication fields (such as, the bitmap, the amplitude coefficients and the phase coefficients) indexed by one or more parameters as below:

● r, layer index,

● i, SD basis index among the plurality of TRPs (e.g. an index of a first basis) ,

● i _t, SD basis index corresponding to a TRP with index t, (e.g. an index of a second basis) ,

● t, TRP index,

● f, FD basis index (e.g. an index of a third basis) , and

● f _t, FD basis index corresponding to a TRP with index t, (e.g. an index of a third basis) .

FIG. 5 illustrates a flowchart of an example method 500 in accordance with some embodiments of the present disclosure. For example, the method 500 can be implemented at the terminal device 220 as shown in FIG. 2A.

At block 510, the terminal device 220 receives at least one configuration for CSI feedback from a network device 210.

At block 520, the terminal device 220 transmits the CSI feedback to the network device 210 based on the at least one configuration. The CSI feedback comprises a plurality of partitions with different omission priorities, and the plurality of partitions comprise parameters associated with one or more of a plurality of CSI-RS allocations.

In some embodiments, the terminal device 220 determines, priorities comprising at least one of the following: a respective first priority for a CSI-RS allocation of the plurality of CSI-RS allocations, or a respective second priority for a parameter of the parameters comprised in the CSI feedback. the terminal device 220 generates the CSI feedback based on the priorities. In other words, the terminal device 220negerates the CSI feedback by including, based on the priorities, the parameters into the plurality of partitions of the CSI feedback.

FIG. 6 illustrates a flowchart of an example method 600 in accordance with some embodiments of the present disclosure. For example, the method 600 can be implemented at the network device 210 as shown in FIG. 2A.

At block 610, the network device 210 transmits at least one configuration for CSI feedback to the terminal device 220.

At block 620, the network device 210 receives the CSI feedback from the terminal device 220 based on the at least one configuration. The CSI feedback comprises a plurality of partitions with different omission priorities, the plurality of partitions comprise parameters associated with one or more of a plurality of CSI-RS allocations.

FIG. 7 is a simplified block diagram of a device 700 that is suitable for implementing embodiments of the present disclosure. The device 700 can be considered as a further example implementation of the terminal device 220 or the network device 210 as shown in FIG. 2. Accordingly, the device 700 can be implemented at or as at least a part of the terminal device 220 or the network device 210.

As shown, the device 700 includes a processor 710, a memory 720 coupled to the processor 710, a suitable transmitter (TX) /receiver (RX) 740 coupled to the processor 710, and a communication interface coupled to the TX/RX 740. The memory 710 stores at least a part of a program 730. The TX/RX 740 is for bidirectional communications. The TX/RX 740 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a Mobility Management Entity (MME) /Access and Mobility Management Function (AMF) /SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN) , or Uu interface for communication between the eNB/gNB and a terminal device.

The program 730 is assumed to include program instructions that, when executed by the associated processor 710, enable the device 700 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGs. 2 to 6. The embodiments herein may be implemented by computer software executable by the processor 710 of the device 700, or by hardware, or by a combination of software and hardware. The processor 710 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 710 and memory 720 may form processing means 770 adapted to implement various embodiments of the present disclosure.

The memory 720 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 720 is shown in the device 700, there may be several physically distinct memory modules in the device 700. The processor 710 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 700 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

In some embodiments, a terminal device 220 comprises a circuitry configured to receive at least one configuration for CSI feedback from a network device 210; and transmit the CSI feedback to the network device 210 based on the at least one configuration. The CSI feedback comprises a plurality of partitions with different omission priorities, and the plurality of partitions comprise parameters associated with one or more of a plurality of CSI-RS allocations.

In some embodiments, the circuitry is further configured to determine, priorities comprising at least one of the following: a respective first priority for a CSI-RS allocation of the plurality of CSI-RS allocations, or a respective second priority for a parameter of the parameters comprised in the CSI feedback. the terminal device 220 generates the CSI feedback based on the priorities. In the other words, the terminal device 220 generates the CSI feedback by including, based on the priorities, the parameters into the plurality of partitions of the CSI feedback.

In another solution, a device of communication comprises: a processor configured to cause the device to perform any of the methods above.

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 representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods 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.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to FIGs. 2 to 6. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

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.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine 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 machine 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.

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 sub-combination.

Although the present disclosure has been described in language 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

A method of communication, comprising:

receiving, at a terminal device and from a network device, at least one configuration for one channel state information (CSI) , wherein the at least one configuration indicates at least one first number of first vectors, at least one first number of second vectors and a number of a first plurality of channel state information reference signal (CSI-RS) resources;

determining a second plurality of CSI-RS resources, wherein the second plurality of CSI-RS resources is same as or a subset of the first plurality of CSI-RS resources;

determining at least one of: at least one second number of selected first vectors based on the second plurality of CSI-RS resources and at least one second number of selected second vectors based on the second plurality of CSI-RS resources and the at least one configuration; and

transmitting, based on the at least one configuration, the CSI to the network device.
The method of claim 1, wherein the at least one first number of first vectors comprises a first set of values, and each value in the first set of values indicates a first number of first vectors corresponding to each one of the first plurality of CSI-RS resources, wherein a number of the first set of values is same as a number of the first plurality of CSI-RS resources; and

the at least one second number of first vectors comprises a second set of values, and each value in the second set of values indicates a second number of first vectors corresponding to each one CSI-RS resource in the second plurality of CSI-RS resources, wherein a number of the second set of values is same as a number of the second plurality of CSI-RS resources, and a value in the second set of values corresponding to a CSI-RS resource is equal to or less than a value in the first set of values corresponding to the same CSI-RS resource, and each value in the second set of values is no less than 1.
The method of claim 1 or 2, wherein the at least one second number of selected first vectors comprises a first value for the first vectors and a second value for the first vectors, and the first value for the first vectors indicates a second number of selected first vectors corresponding to a reference CSI-RS resource in the second plurality of CSI-RS resources, and the second value for the first vectors indicates a second number of selected first vectors corresponding to remaining CSI-RS resources except the reference CSI-RS resource in the second plurality of CSI-RS resources.
The method of claim 3, wherein the at least one first number of first vectors comprises a third value for the first vectors and a fourth value for the first vectors, and the third value for the first vectors is larger than or equal to the first value for the first vectors, and the fourth value for the first vectors is larger than or equal to the second value for the first vectors.
The method of claim 1, further comprising:

determining an index of a second vector corresponding to each one of the second plurality of CSI-RS resources; and

determining a set of selected second vectors from a first plurality of second vectors corresponding to each one of the second plurality of CSI-RS resources, wherein the first plurality of second vectors corresponding to each one of the second plurality of CSI-RS resources is based on the first index of the second vector corresponding to each one of the second plurality of CSI-RS resources and the at least one second number of selected second vectors.
The method of claim 5, further comprising:

determining a first field for indicating a set of selected second vectors corresponding to a reference CSI-RS resource in the second plurality of CSI-RS resources, and the set of selected second vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources comprises a second vector corresponding to a strongest coefficient indication.
The method of claim 5, further comprising:

determining a second field for indicating a set of selected second vectors corresponding to one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources, and the set of selected second vectors corresponding to the one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources comprises a second vector with an index based on a first index of the second vector corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources and a second index of the second vector to the one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources.
The method of claim 1 or 5, further comprising:

determining a set of selected second vectors corresponding to a reference CSI-RS resource in the second plurality of CSI-RS resources;

determining an offset for one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources; and

determining a set of selected second vectors corresponding to one CSI-RS resource except the reference CSI-RS resource in the second plurality of CSI-RS resources based on the offset and the set of selected second vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources, wherein the offset is relative to at least one of:

a first one index of the set of selected second vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources;

a last one index of the set of selected second vectors corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources; and

a first index of the second vector corresponding to the reference CSI-RS resource in the second plurality of CSI-RS resources .
The method of claim 1, wherein the at least one configuration further indicates at least one set of parameters, and each set of parameters comprises a first parameter, a second parameter and a third parameter.
The method of claim 9, wherein the at least one second number of selected second vectors is determined based on a maximum value of the second parameters among the at least one set of parameters.
The method of claim 9, wherein the at least one set of parameters comprises a first value of the second parameter and a second value of the second parameter, and further comprising at least one of:

the at least one second number of selected second vectors is determined based on the first value of the second parameter when the number of the second plurality of CSI-RS resources is 1; and

the at least one second number of selected second vectors is determined based on the second value of the second parameter when the number of the second plurality of CSI-RS resources is 2 or 3 or 4.
The method of claim 1, further comprising:

determining, at the terminal device, a size of a bitmap indicating non zero coefficients corresponding to the second plurality of CSI-RS resources; or

determining, a constraint of a total number of non zero coefficients corresponding to the second plurality of CSI-RS resources.
The method of claim 12, wherein the size of the bitmap indicating non zero coefficients and/or the constraint of the total number of non zero coefficients is determined based on a maximum value of the third parameters among the at least one set of parameters.
The method of claim 9 or 12, wherein the at least one set of parameters comprises a first value of the third parameter and a second value of the third parameter, and further comprising at least one of:

the size of the bitmap indicating non zero coefficients corresponding to the second plurality of CSI-RS resources or the constraint of the total number of non zero coefficients corresponding to the second plurality of CSI-RS resources is determined based on the first value of the third parameter when the number of the second plurality of CSI-RS resources is 1; and

the size of the bitmap indicating non zero coefficients corresponding to the second plurality of CSI-RS resources or the constraint of the total number of non zero coefficients corresponding to the second plurality of CSI-RS resources is determined based on the second value of the third parameter when the number of the second plurality of CSI-RS resources is 2 or 3 or 4.
The method of claim 1, further comprising at least one of:

the at least one first number of first vectors comprises more than one value, and each one of more than one value indicates a number or a maximum number of first vectors to be selected corresponding to each one of the first plurality of CSI-RS resources; and

the at least one first number of first vectors is one value, and the value indicates a total number or a maximum total number of first vectors to be selected corresponding to all of the first plurality of CSI-RS resources or corresponding to all of the second plurality of CSI-RS resources.
A method of communication, comprising:

transmitting, at a network device and to a terminal device, at least one configuration for one channel state information (CSI) , wherein the at least one configuration indicates at least one first number of first vectors, at least one first number of second vectors and a number of a first plurality of channel state information reference signal (CSI-RS) resources; and

receiving, based on the at least one configuration, the CSI from the terminal device.