CSI reporting with frequency-domain compression in a wireless communication system

Abstract

Apparatuses and methods for channel state information (CSI) reporting with frequency-domain compression. A method performed by a user equipment (UE) includes receiving information about a CSI report that indicates an antenna port group and determining, based on the information, a spatial domain (SD) basis vector bl for layer l=1,2…, ν . The method further includes determining, based on the information, a coefficient value cl,n for layer l=1,2…, ν and for subband (SB) n=0,…,N3-1, where ν is a rank value and N3 is a number of SBs and where the coefficient value is represented by a frequency domain (FD) compression component and a coefficient component and transmitting the CSI report including a precoding matrix indicator (PMI). The PMI includes a first indicator for the SD basis vector, a second indicator for the FD compression component, and a third indicator for the coefficient component. The present disclosure relates to a 5G communication system or a 6G communication system for supporting higher data rates beyond a 4G communication system such as long term evolution (LTE).

Description

CSI REPORTING WITH FREQUENCY-DOMAIN COMPRESSION IN A WIRELESS COMMUNICATION SYSTEM

[0001] The present disclosure relates generally to wireless communication systems and, more specifically, to channel state information (CSI) reporting with frequency-domain compression.

[0002] Considering the development of wireless communication from generation to generation, the technologies have been developed mainly for services targeting humans, such as voice calls, multimedia services, and data services. Following the commercialization of 5G (5th generation) communication systems, it is expected that the number of connected devices will exponentially grow. Increasingly, these will be connected to communication networks. Examples of connected things may include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machines, and factory equipment. Mobile devices are expected to evolve in various form-factors, such as augmented reality glasses, virtual reality headsets, and hologram devices. In order to provide various services by connecting hundreds of billions of devices and things in the 6G (6th generation) era, there have been ongoing efforts to develop improved 6G communication systems. For these reasons, 6G communication systems are referred to as beyond-5G systems.

[0003] 6G communication systems, which are expected to be commercialized around 2030, will have a peak data rate of tera (1,000 giga)-level bit per second (bps) and a radio latency less than 100μsec, and thus will be 50 times as fast as 5G communication systems and have the 1 / 10 radio latency thereof.

[0004] In order to accomplish such a high data rate and an ultra-low latency, it has been considered to implement 6G communication systems in a terahertz (THz) band (for example, 95 gigahertz (GHz) to 3THz bands). It is expected that, due to severer path loss and atmospheric absorption in the terahertz bands than those in mmWave bands introduced in 5G, technologies capable of securing the signal transmission distance (that is, coverage) will become more crucial. It is necessary to develop, as major technologies for securing the coverage, Radio Frequency (RF) elements, antennas, novel waveforms having a better coverage than Orthogonal Frequency Division Multiplexing (OFDM), beamforming and massive Multiple-input Multiple-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antennas, and multiantenna transmission technologies such as large-scale antennas. In addition, there has been ongoing discussion on new technologies for improving the coverage of terahertz-band signals, such as metamaterial-based lenses and antennas, Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surface (RIS).

[0005] Moreover, in order to improve the spectral efficiency and the overall network performances, the following technologies have been developed for 6G communication systems: a full-duplex technology for enabling an uplink transmission and a downlink transmission to simultaneously use the same frequency resource at the same time; a network technology for utilizing satellites, High-Altitude Platform Stations (HAPS), and the like in an integrated manner; an improved network structure for supporting mobile base stations and the like and enabling network operation optimization and automation and the like; a dynamic spectrum sharing technology via collision avoidance based on a prediction of spectrum usage; an use of Artificial Intelligence (AI) in wireless communication for improvement of overall network operation by utilizing AI from a designing phase for developing 6G and internalizing end-to-end AI support functions; and a next-generation distributed computing technology for overcoming the limit of UE computing ability through reachable super-high-performance communication and computing resources (such as Mobile Edge Computing (MEC), clouds, and the like) over the network. In addition, through designing new protocols to be used in 6G communication systems, developing mechanisms for implementing a hardware-based security environment and safe use of data, and developing technologies for maintaining privacy, attempts to strengthen the connectivity between devices, optimize the network, promote softwarization of network entities, and increase the openness of wireless communications are continuing.

[0006] It is expected that research and development of 6G communication systems in hyper-connectivity, including person to machine (P2M) as well as machine to machine (M2M), will allow the next hyper-connected experience. Particularly, it is expected that services such as truly immersive eXtended Reality (XR), high-fidelity mobile hologram, and digital replica could be provided through 6G communication systems. In addition, services such as remote surgery for security and reliability enhancement, industrial automation, and emergency response will be provided through the 6G communication system such that the technologies could be applied in various fields such as industry, medical care, automobiles, and home appliances.

[0007] The present disclosure relates to csi reporting with frequency-domain compression in a wireless communication system.

[0008] According to an aspect of an exemplary embodiment, there is provided a communication method in a wireless communication system.

[0009] Aspects of the present disclosure provide efficient communication methods in a wireless communication system.

[0010] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

[0011] FIG. 1 illustrates an example wireless network according to embodiments of the present disclosure;

[0012] FIG. 2 illustrates an example gNodeB (gNB) according to embodiments of the present disclosure;

[0013] FIG. 3 illustrates an example UE according to embodiments of the present disclosure;

[0014] FIG. 4A illustrates an example of a wireless transmit and receive paths according to embodiments of the present disclosure;

[0015] FIG. 4B illustrates an example of a wireless transmit and receive paths according to embodiments of the present disclosure;

[0016] FIG. 5 illustrates an example of a transmitter structure for beamforming according to embodiments of the present disclosure;

[0017] FIG. 6 illustrates an example of a transmitter structure for physical downlink shared channel (PDSCH) in a subframe according to embodiments of the present disclosure;

[0018] FIG. 7 illustrates an example of a receiver structure for PDSCH in a subframe according to embodiments of the present disclosure;

[0019] FIG. 8 illustrates an example of a transmitter structure for physical uplink shared channel (PUSCH) in a subframe according to embodiments of the present disclosure;

[0020] FIG. 9 illustrates an example of a receiver structure for a PUSCH in a subframe according to embodiments of the present disclosure;

[0021] FIG. 10 illustrates a diagram of an antenna port layout according to embodiments of the present disclosure;

[0022] FIG. 11 illustrates examples co-located and distributed antenna groups (AGs) / port groups (PGs) serving a moving UE according to embodiments of the present disclosure;

[0023] FIG. 12 illustrates an example of a timeline for a UE to receive nonzero power (NZP) CSI reference signal (CSI-RS) resource(s) bursts according to embodiments of the present disclosure;

[0024] FIG. 13 illustrates examples of timelines for partitioned CSI-RS burst instances according to embodiments of the present disclosure;

[0025] FIG. 14 illustrates an example of resource block (RB) and subband (SB) partitions according to embodiments of the present disclosure;

[0026] FIG. 15 illustrates an example of SD units, frequency-domain (FD) units, and time domain (TD) units according to embodiments of the present disclosure;

[0027] FIG. 16 illustrates an example of codebook based components used for determining a CSI report according to embodiments of the present disclosure;

[0028] FIG. 17 illustrates an example of an orthogonal basis set according to embodiments of the present disclosure;

[0029] FIG. 18 illustrates an example of a beam sorting (numbering) scheme according to embodiments of the present disclosure; and

[0030] FIG. 19 illustrates an example method performed by a UE in a wireless communication system according to embodiments of the present disclosure.

[0031] FIG. 20 is a block diagram of a terminal or user equipment (UE) 2000 according to an embodiment of the disclosure;

[0032] FIG. 21 is a block diagram of a base station (BS) 2100 according to an embodiment of the disclosure; and

[0033] FIG. 22 is a block diagram of a network entity 2200 according to an embodiment of the disclosure.

[0034] The present disclosure relates to CSI reporting with frequency-domain compression.

[0035] In one embodiment, a user equipment (UE) is provided. The UE includes a transceiver configured to receive information about a CSI report and a processor operably coupled to the transceiver. The information indicates an antenna port group. The processor is configured to determine, based on the information, a spatial domain (SD) basis vector blfor layer l=1,2…, ; and determine, based on the information, a coefficient value cl,nfor layer l=1,2…, and for subband (SB) n=0,…,N3-1, where is a rank value and N3is a number of SBs. The coefficient value is represented by a frequency domain (FD) compression component and a coefficient component. The transceiver is further configured to transmit the CSI report including a precoding matrix indicator (PMI). The PMI includes a first indicator for the SD basis vector, a second indicator for the FD compression component, and a third indicator for the coefficient component.

[0036] In another embodiment, a base station (BS) is provided. The BS includes a processor and a transceiver operably coupled to the processor. The transceiver is configured to transmit information about a CSI report that indicates an antenna port group and receive the CSI report including a PMI. The PMI includes a first indicator for a SD basis vector blfor layer l=1,2…, , a second indicator for a FD compression component, and a third indicator for a coefficient component. The FD compression component and the coefficient component represent a coefficient value cl,nfor layer l=1,2…, and for SB n=0,…,N3-1, where is a rank value and N3is a number of SBs.

[0037] In yet another embodiment, a method performed by a UE is provided. The method includes receiving information about a CSI report that indicates an antenna port group and determining, based on the information, a SD basis vector blfor layer l=1,2…, . The method further includes determining, based on the information, a coefficient value cl,nfor layer l=1,2…, and for SB n=0,…,N3-1, where v is a rank value and N3is a number of SBs and where the coefficient value is represented by a FD compression component and a coefficient component and transmitting the CSI report including a PMI. The PMI includes a first indicator for the SD basis vector, a second indicator for the FD compression component, and a third indicator for the coefficient component.

[0038] Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term “couple” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms “transmit,” “receive,” and “communicate,” as well as derivatives thereof, encompass both direct and indirect communication. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and / or. The phrase “associated with,” as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term “controller” means any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase “at least one of,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, “at least one of: A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

[0039] Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

[0040] Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.

[0041] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

[0042] In describing the embodiments, while numerous details are set forth for the purpose of illustration, it is understood that some aspects of the disclosure may be practiced with less than all of these details. Numerous variations and alternatives to the details provided herein are possible and are considered within the scope of the disclosure. In some instances, descriptions related to technical contents well-known in the art may be omitted so as to not obscure an understanding of the disclosure, and such omitted descriptions are understood to be within the scope of the disclosure.

[0043] For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted, or schematically illustrated. Further, the size of each element does not completely reflect the actual size. In the drawings, identical or corresponding elements are provided with identical reference numerals or different reference numerals.

[0044] The advantages and features of the disclosure and ways to achieve them will be apparent by making reference to embodiments as described herein in detail in conjunction with the accompanying drawings. However, the disclosure is not limited to the embodiments set forth herein, but may be implemented in various different forms. Other features, aspects, and advantages of the subject matter described herein will become apparent from the disclosure. The following embodiments are merely examples to aid in an understanding of the disclosure and should not be construed to narrow the scope or spirit of the subject matter described herein in any way, but on the contrary, the disclosure covers all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims and equivalents thereof. Throughout the specification, the same or like reference numerals designate the same or like elements. Furthermore, terms which will be described herein are terms defined in consideration of the functions in the disclosure, and may be different according to users, intentions of the operators, or customs. Therefore, the definitions of the terms should be made based on the contents throughout the specification.

[0045] Herein, it will be understood that each block of flowchart illustrations, and combinations of blocks in the flowchart illustrations, may be performed based on computer program instructions. These computer program instructions may be loaded collectively onto at least one processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which perform through any one of, or in any combination of, the at least one processor of the computer or other programmable data processing apparatus, create means for performing the functions specified in the flowchart block(s). These computer program instructions may also be stored in a non-transitory computer usable or computer-readable memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instruction means that perform the function specified in the flowchart block(s). The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable data processing apparatus to produce a computer executed process such that the instructions that perform on the computer or other programmable data processing apparatus provide steps for executing the functions specified in the flowchart block(s).

[0046] Further, each block may represent a module, segment, or portion of code, which includes one or more executable instructions for executing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of the order. For example, two blocks(or functions) shown in succession may in fact be performed substantially concurrently or the blocks may sometimes be performed in the reverse order, depending upon the functionality involved.

[0047] As used in embodiments of the disclosure, a “~unit / module” may refer to a software element or a hardware element, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), which performs a predetermined function. However, the term including the word “~unit / module” does not always have a meaning limited to software or hardware. The “~unit / module” may be constructed either to be stored in an addressable storage medium or to execute one or more processors. Therefore, the “~unit / module” includes, for example, software elements, object-oriented software elements, components such as class elements and task elements, processes, functions, properties, procedures, sub-routines, segments of a program code, drivers, firmware, micro-codes, circuits, data, database, data structures, tables, arrays, and parameters. The components and functions provided by the “~unit / module” may be either combined into a smaller number of components and a “~unit / module,” or divided into additional components and a “~unit / module.” Moreover, the components and “~units / modules” may be implemented to reproduce one or more central processing units (CPUs) within a device or a security multimedia card. Further, in the embodiments, the “～unit / module” may include one or more processors.

[0048] The entirety of the one or more computer programs may be stored in a single memory device or the one or more computer programs may be divided with different portions stored in different multiple memory devices.

[0049] Any of the functions or operations described herein can be processed by one processor or a combination of processors. The one processor or the combination of processors is circuitry performing processing and includes circuitry like an application processor (AP, e.g. a CPU), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a Wi-Fi chip, a Bluetooth® chip, a global positioning system (GPS) chip, a near field communication (NFC) chip, connectivity chips, a sensor controller, a touch controller, a finger-print sensor controller, a display driver integrated circuit (IC), an audio CODEC chip, a universal serial bus (USB) controller, a camera controller, an image processing IC, microprocessors, microcontrollers, digital signal processors, FPGA, ASIC, a microprocessor unit (MPU), a system on chip (SoC), an IC, or the like. The one processor or the combination of processors executes instructions that can be stored in a memory, such as the operating system, in order to control the overall operation of the device. Also, the one processor or the combination of processors is also capable of executing other processes and programs resident in the memory, such as processes for the disclosure.

[0050] It will be appreciated that various embodiments of the disclosure according to the claims and description in the specification can be realized in the form of hardware, software or a combination of hardware and software.

[0051] Any such software may be stored in non-transitory computer readable storage media. The non-transitory computer readable storage media store one or more computer programs (software modules), the one or more computer programs include computer-executable instructions that, when executed by one or more processors of an electronic device individually or collectively, cause the electronic device to perform a method of the disclosure. Additionally, or alternatively, such software may be a computer program [product] comprising instructions which, when executed by one or more processors of an electronic device individually or collectively, cause the electronic device to perform a method of the disclosure.

[0052] Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like read only memory (ROM), whether erasable or rewritable or not, or in the form of memory such as, for example, random access memory (RAM), memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a compact disk (CD), digital versatile disc (DVD), magnetic disk or magnetic tape or the like. It will be appreciated that the storage devices and storage media are various embodiments of non-transitory machine-readable storage that are suitable for storing a computer program or computer programs comprising instructions that, when executed, implement various embodiments of the disclosure. Accordingly, various embodiments of the present disclosure may provide a program comprising code for implementing apparatus or a method as claimed in any one of the claims of this specification and a non-transitory machine-readable storage storing such a program.

[0053] Hereinafter, the determination of priority between A and B in the present disclosure may refer to various actions such as selecting the one having a higher priority based on a predefined priority rule and performing an operation corresponding thereto, or omitting or dropping an operation corresponding to the one having a lower priority.

[0054] Hereinafter, "A or B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0055] In addition, "at least one of A, B, and C" as described in the present disclosure may be understood to include A, or B, or C, or any combination of A, B, and C.

[0056] In addition, "at least one of A, B, or C" as described in the present disclosure may be understood to include A, or B, or C, or any combination of A, B, and C.

[0057] Furthermore, "A / B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0058] Furthermore, "A, B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0059] Furthermore, "A and B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0060] Furthermore, “if condition A and condition B are satisfied,” as described in the present disclosure, may not be limited to a case where both condition A and condition B are satisfied, but may be understood to include a case where either condition A or condition B is individually satisfied, both condition A and condition B are satisfied, or one or more additional conditions are satisfied in combination.

[0061] Furthermore, throughout this disclosure, ordinal terms such as "first," "second," "third," etc., (and similar qualifiers) are used merely to distinguish between different instances, occurrences, configurations, messages, stages, elements or aspects of elements, operations, or information as described herein. Unless the context clearly dictates otherwise, the use of such ordinal terms does not itself require that the elements, operations, or information distinguished by these terms be structurally different, numerically distinct, or substantively dissimilar. For example, a "first signal" and a "second signal" may refer to instances of the same signal transmitted at different times or containing the same core information despite minor variations, or they may refer to signals with different content or characteristics, depending on the specific context. Similarly, a "first value" and a "second value" may represent the same magnitude but measured or applied in different circumstances, or they may represent different magnitudes. The interpretation should be guided by the specific technical context, function, and relationship described in the relevant portion of the specification and claims.

[0062] Furthermore, the terms “first ~”, “second ~”, etc., as described in the present disclosure with respect to various elements (e.g., information, objects, operation, sequences, or the like), should not limit those elements. These terms may only be intended to distinguish one element from another, and may not be intended to indicate a specific order. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element.

[0063] Furthermore, even if “first ~” and “second ~” are described in the present disclosure, it may be understood that element(s) referred to by “first ~” and “second ~” may be the same or different. For example, in case of element(s) being information, first information and second information may both be same information and, in some cases, are separate and different information.

[0064] In addition, the terms “if ~” and “in case that ~” as used in the disclosure or claims may be interpreted to include the meanings of “when (or upon) ~,” “in response to ~,” “based on ~,” or “according to ~,” and may be used interchangeably with these expressions. In addition, expressions other than those exemplified herein may also be used, as long as they have substantially the same meaning and do not impair the technical features of the present disclosure. If a method step (e.g. transmit a signal) is performed according to the disclosure of the application in connection with one of the above terms (such as “in case that ~” or the like), it may be interpreted to include the meanings (disclosure) of a prior determination that a feature has a specific state “~” (e.g. a bit length is above X), and then perform the method step in response to said determination.

[0065] For example, the physical layer signaling may be referred to as Layer 1 (L1) signaling and may include downlink control information (DCI). In addition, the higher layer signaling may include a medium access control (MAC) control message, a radio resource control (RRC) signaling message, a non-access stratum (NAS) signaling message, or an application layer message. The RRC signaling message may be referred to as L3 (layer 3) signaling. It should be noted, however, that the higher layer signaling is not limited to the aforementioned examples.

[0066] In addition, the term "not perform" as used in the present disclosure or claims may, in context, be understood to mean that the corresponding step is omitted or skipped. Such a term may be replaced with other terms having the same or substantially equivalent meaning.

[0067] In addition, "transmitting a message including A and B" as described in the present disclosure, may be understood as encompassing both (i) transmitting A and B in a single message, and (ii) transmitting A and B separately via multiple messages (e.g., transmitting a first message including A and a second message including B). This interpretation may also apply to messages that include two or more items (e.g., A, B, C), transmitted either together or separately.

[0068] In addition, "transmitting a message including A and transmitting a message including B" may also be interpreted as transmitting a message including A and B in a single message.

[0069] In the embodiments of the present disclosure described herein, terms or components included in the disclosure may be expressed in singular or plural form depending on the specific embodiments presented. However, such singular or plural expressions are selected appropriately for convenience of description, and the present disclosure is not limited to a singular or plural number of components. A component expressed in the plural form may be implemented as a single component, and a component expressed in the singular form may be implemented as multiple components.

[0070] The drawings or flowcharts described herein illustrate example methods that may be implemented according to the principles of the present disclosure, and various modifications may be made to the methods illustrated in the flowcharts of the present disclosure. For example, although illustrated as a series of steps, various steps in each drawing or flowchart may overlap, occur in parallel, occur in a different order, or be repeated. In other examples, any step may be omitted or replaced with another step.

[0071] The process of the flowchart may be performed by a device. One or more of the steps of the flowchart can be implemented by one or more processors / computer programs executing instructions to perform the noted functions.

[0072] The methods and apparatuses proposed in the embodiments of the present disclosure may be disclosed in connection with drawings disclosing flowcharts to illustrate example methods that may be implemented according to the principles of the present disclosure. Such flowcharts may contain different branches and / or sub-branches. It is understood that the principles of the present disclosure do not only contain the combination of all branches / sub-branches disclosed in the embodiment, but the present disclosure also contains at least one isolated branch / isolated sub-branch, in particular to a single branch / single sub-branch.

[0073] The methods and apparatuses proposed in the embodiments of the present disclosure are not limited to each embodiment individually, but may also be applied in combination of all or some of the embodiments proposed in the disclosure. Therefore, the embodiments of the present disclosure may be modified and applied without significantly departing from the scope of the present disclosure, as would be understood by those skilled in the art.

[0074] In this case, even if certain wordings are described differently across embodiments, they may be used interchangeably or in substitution or in combination if their underlying concepts are equivalent. For example, for the same or equivalent concept, even if one embodiment uses the expression "A" and another embodiment uses the expression "B", such expressions may be understood interchangeably, in substitution, or in combination.

[0075] The terms used in the following description to refer to access nodes, network entities, messages, interfaces between network entities, various types of identification information, and the like, are provided merely for the convenience of explanation by way of example. Therefore, the present disclosure is not limited to the terms describedherein, and other terms having equivalent technical meanings may also be used. Such terms may also be interchangeable with terms defined in any 3rd generation partnership project (3GPP) technical specifications (TS) or similar technical specifications, e.g., from the European telecommunications standards institute (ETSI), where appropriate.

[0076] Hereinafter, a base station (BS) is an entity that allocates resources to terminals, and may be at least one of a gNode B, an eNode B, a Node B, a wireless access unit, a BS controller, or a node on a network.

[0077] Furthermore, the base station of the present disclosure may include a split architecture comprising a central unit (CU) and a distributed unit (DU). In this structure, the CU is configured to process the higher layers of the control and user planes, while the DU is configured to process lower-layer radio resource functions. The embodiments of the present disclosure may be equally applicable to 5th generation (5G) base station architectures in which such CU and DU functional splits are implemented.

[0078] A terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, a tablet, a wearable device, an Internet of Things (IoT) device, or any other device / system capable of performing communication functions.

[0079] In the disclosure, a downlink (DL) refers to a radio link through which a BS transmits a signal to a terminal, and an uplink (UL) refers to a radio link through which a terminal transmits a signal to a BS.

[0080] Furthermore, hereinafter, 5G mobile communication technologies (e.g., 5G new radio (NR)), 6th generation (6G) mobile communication technologies may be described by way of example, but the embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, newly evolved mobile communication systems developed after 5G and 6G may be included. Furthermore, based on determinations by those skilled in the art, the embodiments of the present disclosure may also be applied to other communication systems (e.g., Wi-Fi systems) through some modifications without significantly departing from the scope of the present disclosure

[0081] In the following description, the terms physical channel and signal may be used interchangeably with data or control signal. For example, the term physical downlink shared channel (PDSCH) refers to a physical channel through which data is transmitted, but the term PDSCH may also be used to refer to the data itself. That is, in the present disclosure, the expression "transmit a physical channel" may be interpreted as being equivalent to the expression "transmit data or a signal via a physical channel."

[0082] Hereinafter, in the context of the present disclosure, higher layer signaling may refer to signaling corresponding to at least one or any combination of the following: master information block (MIB), system information block (SIB) or SIB M (M = 1, 2, ...), RRC, or MAC control element (CE), or a non-access stratum (NAS) signaling message, or an application layer message. The RRC signaling message may be referred to as Layer 3 (L3) signaling.

[0083] In addition, L1 signaling may refer to signaling corresponding to at least one or any combination of signaling techniques using the at least one or any combination of the following physical layer channels or signaling: physical downlink control channel (PDCCH), DCI, UE-specific DCI, group-common DCI, common DCI, scheduling DCI (e.g., DCI used for scheduling downlink or uplink data), non-scheduling DCI (e.g., DCI not used for scheduling downlink or uplink data) physical uplink control channel (PUCCH), or uplink control information (UCI). The L1 signaling message may be referred to as a physical layer signaling.

[0084] Hereinafter, the expression that information is configured by the BS, as used in the present disclosure or claims, may, in context, be understood to mean that the terminal receives the corresponding information from the BS via a physical layer signaling or a higher layer signaling. Such an expression may be replaced with other terms having the same or substantially equivalent meaning.

[0085] Hereinafter, the operational principle of the present disclosure will be described in detail with reference to the accompanying drawings.

[0086] The present application claims priority under 35 U.S.C. § 119(e) to: U.S. Provisional Patent Application No. 63 / 746,152 filed January 16, 2025. The above identified provisional patent application is hereby incorporated by reference in its entirety.

[0087] Wireless communication has been one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services exceeded five billion and continues to grow quickly. The demand of wireless data traffic is rapidly increasing due to the growing popularity among consumers and businesses of smart phones and other mobile data devices, such as tablets, "note pad" computers, net books, eBook readers, and machine type of devices. In order to meet the high growth in mobile data traffic and support new applications and deployments, improvements in radio interface efficiency and coverage are of paramount importance. To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, and to enable various vertical applications, 5G communication systems have been developed and are currently being deployed.

[0088] FIGS. 1-19 discussed below, and the various, non-limiting embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.

[0089] To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, and to enable various vertical applications, 5G / NR communication systems have been developed and are currently being deployed. The 5G / NR communication system is implemented in higher frequency (mmWave) bands, e.g., 28 GHz or 60GHz bands, so as to accomplish higher data rates or in lower frequency bands, such as 6 GHz, to enable robust coverage and mobility support. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G / NR communication systems.

[0090] In addition, in 5G / NR communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancelation and the like.

[0091] The discussion of 5G systems and frequency bands associated therewith is for reference as certain embodiments of the present disclosure may be implemented in 5G systems. However, the present disclosure is not limited to 5G systems, or the frequency bands associated therewith, and embodiments of the present disclosure may be utilized in connection with any frequency band. For example, aspects of the present disclosure may also be applied to deployment of 5G communication systems, 6G, or even later releases which may use terahertz (THz) bands.

[0092] The following documents and standards descriptions are hereby incorporated by reference into the present disclosure as if fully set forth herein: [REF 1] 3GPP TS 36.211 v18.0.1, "E-UTRA, Physical channels and modulation;" [REF 2] 3GPP TS 36.212 v18.1.0, "E-UTRA, Multiplexing and Channel coding;" [REF 3] 3GPP TS 36.213 v18.3.0, "E-UTRA, Physical Layer Procedures;" [REF 4] 3GPP TS 36.321 v18.3.0, "E-UTRA, Medium Access Control (MAC) protocol specification;" [REF　5] 3GPP TS 36.331 v18.4.0, "E-UTRA, Radio Resource Control (RRC) Protocol Specification;" [REF　6] 3GPP TR 22.891 v1.2.0; [REF 7] 3GPP TS 38.212 v18.4.0, "E-UTRA, NR, Multiplexing and Channel coding;" [REF 8] 3GPP TS 38.214 v18.4.0, "E-UTRA, NR, Physical layer procedures for data;" [REF 9] 3GPP TS 38.211 v18.4.0, "E-UTRA, NR, Physical channels and modulation."

[0093] FIGS. 1-3 below describe various embodiments implemented in wireless communications systems and with the use of orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication techniques. The descriptions of FIGS. 1-3 are not meant to imply physical or architectural limitations to how different embodiments may be implemented. Different embodiments of the present disclosure may be implemented in any suitably arranged communications system.

[0094] FIG. 1 illustrates an example wireless network 100 according to embodiments of the present disclosure. The embodiment of the wireless network 100 shown in FIG. 1 is for illustration only. Other embodiments of the wireless network 100 could be used without departing from the scope of the present disclosure.

[0095] As shown in FIG. 1, the wireless network 100 includes a gNB 101 (e.g., base station, BS), a gNB 102, and a gNB 103. The gNB 101 communicates with the gNB 102 and the gNB 103. The gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0096] The gNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipments (UEs) within a coverage area 120 of the gNB 102. The first plurality of UEs includes a UE 111, which may be located in a small business; a UE 112, which may be located in an enterprise; a UE 113, which may be a WiFi hotspot; a UE 114, which may be located in a first residence; a UE 115, which may be located in a second residence; and a UE 116, which may be a mobile device, such as a cell phone, a wireless laptop, a wireless PDA, or the like. The gNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the gNB 103. The second plurality of UEs includes the UE 115 and the UE 116. In some embodiments, one or more of the gNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G / NR, long term evolution (LTE), long term evolution-advanced (LTE-A), WiMAX, WiFi, or other wireless communication techniques.

[0097] Depending on the network type, the term "base station" or "BS" can refer to any component (or collection of components) configured to provide wireless access to a network, such as transmit point (TP), transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G / NR base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wirelessly enabled devices. Base stations may provide wireless access in accordance with one or more wireless communication protocols, e.g., 5G / NR 3rdgeneration partnership project (3GPP) NR, long term evolution (LTE), LTE advanced (LTE-A), high speed packet access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. For the sake of convenience, the terms "BS" and "TRP" are used interchangeably in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, the term "user equipment" or "UE" can refer to any component such as "mobile station," "subscriber station," "remote terminal," "wireless terminal," "receive point," or "user device." For the sake of convenience, the terms "user equipment" and "UE" are used in this patent document to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or vending machine).

[0098] The dotted lines show the approximate extents of the coverage areas 120 and 125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending upon the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstructions.

[0099] As described in more detail below, one or more of the UEs 111-116 include circuitry, programing, or a combination thereof for CSI(channel state information) reporting with frequency-domain compression. In certain embodiments, one or more of the BSs 101-103 include circuitry, programing, or a combination thereof to support CSI reporting with frequency-domain compression.

[0100] Although FIG. 1 illustrates one example of a wireless network, various changes may be made to FIG. 1. For example, the wireless network 100 could include any number of gNBs and any number of UEs in any suitable arrangement. Also, the gNB 101 could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network 130. Similarly, each gNB 102-103 could communicate directly with the network 130 and provide UEs with direct wireless broadband access to the network 130. Further, the gNBs 101, 102, and / or 103 could provide access to other or additional external networks, such as external telephone networks or other types of data networks.

[0101] FIG. 2 illustrates an example gNB 102 according to embodiments of the present disclosure. The embodiment of the gNB 102 illustrated in FIG. 2 is for illustration only, and the gNBs 101 and 103 of FIG. 1 could have the same or similar configuration. However, gNBs come in a wide variety of configurations, and FIG. 2 does not limit the scope of the present disclosure to any particular implementation of a gNB.

[0102] As shown in FIG. 2, the gNB 102 includes multiple antennas 205a-205n, multiple transceivers 210a-210n, a controller / processor 225, a memory 230, and a backhaul or network interface 235.

[0103] The transceivers 210a-210n receive, from the antennas 205a-205n, incoming radio frequency (RF) signals, such as signals transmitted by UEs in the wireless network 100. The transceivers 210a-210n down-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are processed by receive (RX) processing circuitry in the transceivers 210a-210n and / or controller / processor 225, which generates processed baseband signals by filtering, decoding, and / or digitizing the baseband or IF signals. The controller / processor 225 may further process the baseband signals.

[0104] Transmit (TX) processing circuitry in the transceivers 210a-210n and / or controller / processor 225 receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller / processor 225. The TX processing circuitry encodes, multiplexes, and / or digitizes the outgoing baseband data to generate processed baseband or IF signals. The transceivers 210a-210n up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 205a-205n.

[0105] The controller / processor 225 can include one or more processors or other processing devices that control the overall operation of the gNB 102. For example, the controller / processor 225 could control the reception of uplink (UL) channel signals and the transmission of downlink (DL) channel signals by the transceivers 210a-210n in accordance with well-known principles. The controller / processor 225 could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller / processor 225 could support beam forming or directional routing operations in which outgoing / incoming signals from / to multiple antennas 205a-205n are weighted differently to effectively steer the outgoing signals in a desired direction. As another example, the controller / processor 225 could support methods for CSI configurations in TDD(time division duplexing) scenarios. Any of a wide variety of other functions could be supported in the gNB 102 by the controller / processor 225.

[0106] The controller / processor 225 is also capable of executing programs and other processes resident in the memory 230, such as processes to support CSI reporting with frequency-domain compression. The controller / processor 225 can move data into or out of the memory 230 as required by an executing process.

[0107] The controller / processor 225 is also coupled to the backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. The interface 235 could support communications over any suitable wired or wireless connection(s). For example, when the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G / NR, LTE, or LTE-A), the interface 235 could allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 could allow the gNB 102 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface 235 includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or transceiver.

[0108] The memory 230 is coupled to the controller / processor 225. Part of the memory 230 could include a RAM, and another part of the memory 230 could include a Flash memory or other ROM.

[0109] Although FIG. 2 illustrates one example of gNB 102, various changes may be made to FIG. 2. For example, the gNB 102 could include any number of each component shown in FIG. 2. Also, various components in FIG. 2 could be combined, further subdivided, or omitted and additional components could be added according to particular needs.

[0110] FIG. 3 illustrates an example UE 116 according to embodiments of the present disclosure. The embodiment of the UE 116 illustrated in FIG. 3 is for illustration only, and the UEs 111-115 of FIG. 1 could have the same or similar configuration. However, UEs come in a wide variety of configurations, and FIG. 3 does not limit the scope of the present disclosure to any particular implementation of a UE.

[0111] As shown in FIG. 3, the UE　116 includes antenna(s) 305, a transceiver(s) 310, and a microphone 320. The UE　116 also includes a speaker 330, a processor 340, an input / output (I / O) interface (IF) 345, an input 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) 361 and one or more applications 362.

[0112] The transceiver(s) 310 receives from the antenna(s) 305, an incoming RF signal transmitted by a gNB of the wireless network 100. The transceiver(s) 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is processed by RX processing circuitry in the transceiver(s) 310 and / or processor 340, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. The RX processing circuitry sends the processed baseband signal to the speaker 330 (such as for voice data) or is processed by the processor 340 (such as for web browsing data).

[0113] TX processing circuitry in the transceiver(s) 310 and / or processor 340 receives analog or digital voice data from the microphone 320 or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the processor 340. The TX processing circuitry encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The transceiver(s) 310 up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna(s) 305.

[0114] The processor 340 can include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 in order to control the overall operation of the UE 116. For example, the processor 340 could control the reception of DL channel signals and the transmission of UL channel signals by the transceiver(s) 310 in accordance with well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

[0115] The processor 340 is also capable of executing other processes and programs resident in the memory 360. For example, the processor 340 may execute processes for CSI reporting with frequency-domain compression as described in embodiments of the present disclosure. The processor 340 can move data into or out of the memory 360 as required by an executing process. In some embodiments, the processor 340 is configured to execute the applications 362 based on the OS 361 or in response to signals received from gNBs or an operator. The processor 340 is also coupled to the I / O interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. The I / O interface 345 is the communication path between these accessories and the processor 340.

[0116] The processor 340 is also coupled to the input 350, which includes, for example, a touchscreen, keypad, etc., and the display 355. The operator of the UE 116 can use the input 350 to enter data into the UE 116. The display 355 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and / or at least limited graphics, such as from web sites.

[0117] The memory 360 is coupled to the processor 340. Part of the memory 360 could include a random-access memory (RAM), and another part of the memory 360 could include a Flash memory or other read-only memory (ROM).

[0118] Although FIG. 3 illustrates one example of UE 116, various changes may be made to FIG. 3. For example, various components in FIG. 3 could be combined, further subdivided, or omitted and additional components could be added according to particular needs. As a particular example, the processor 340 could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). In another example, the transceiver(s) 310 may include any number of transceivers and signal processing chains and may be connected to any number of antennas. Also, while FIG. 3 illustrates the UE 116 configured as a mobile telephone or smartphone, UEs could be configured to operate as other types of mobile or stationary devices.

[0119] FIG. 4A and FIG. 4B illustrate an example of wireless transmit and receive paths 400 and 450, respectively, according to embodiments of the present disclosure. For example, a transmit path 400 may be described as being implemented in a gNB (such as gNB 102), while a receive path 450 may be described as being implemented in a UE (such as UE 116). However, it will be understood that the receive path 450 can be implemented in a gNB and that the transmit path 400 can be implemented in a UE. In some embodiments, the transmit path 400 is configured for CSI reporting with frequency-domain compression.

[0120] As illustrated in FIG. 4A, the transmit path 400 includes a channel coding and modulation block 405, a serial-to-parallel (S-to-P) block 410, a size N Inverse Fast Fourier Transform (IFFT) block 415, a parallel-to-serial (P-to-S) block 420, an add cyclic prefix block 425, and an up-converter (UC) 430. The receive path 450 includes a down-converter (DC) 455, a remove cyclic prefix block 460, a S-to-P block 465, a size N Fast Fourier Transform (FFT) block 470, a parallel-to-serial (P-to-S) block 475, and a channel decoding and demodulation block 480.

[0121] In the transmit path 400, the channel coding and modulation block 405 receives a set of information bits, applies coding (such as a low-density parity check (LDPC) coding), and modulates the input bits (such as with Quadrature Phase Shift Keying (QPSK) or Quadrature Amplitude Modulation (QAM)) to generate a sequence of frequency-domain modulation symbols. The serial-to-parallel block 410 converts (such as de-multiplexes) the serial modulated symbols to parallel data in order to generate N parallel symbol streams, where N is the IFFT / FFT size used in the gNB and the UE. The size N IFFT block 415 performs an IFFT operation on the N parallel symbol streams to generate time-domain output signals. The parallel-to-serial block 420 converts (such as multiplexes) the parallel time-domain output symbols from the size N IFFT block 415 in order to generate a serial time-domain signal. The add cyclic prefix block 425 inserts a cyclic prefix to the time-domain signal. The up-converter 430 modulates (such as up-converts) the output of the add cyclic prefix block 425 to a RF frequency for transmission via a wireless channel. The signal may also be filtered at a baseband before conversion to the RF frequency.

[0122] As illustrated in FIG. 4B, the down-converter 455 down-converts the received signal to a baseband frequency, and the remove cyclic prefix block 460 removes the cyclic prefix to generate a serial time-domain baseband signal. The serial-to-parallel block 465 converts the time-domain baseband signal to parallel time-domain signals. The size N FFT block 470 performs an FFT algorithm to generate N parallel frequency-domain signals. The (P-to-S) block 475 converts the parallel frequency-domain signals to a sequence of modulated data symbols. The channel decoding and demodulation block 480 demodulates and decodes the modulated symbols to recover the original input data stream.

[0123] Each of the gNBs 101-103 may implement a transmit path 400 that is analogous to transmitting in the downlink to UEs 111-116 and may implement a receive path 450 that is analogous to receiving in the uplink from UEs 111-116. Similarly, each of UEs 111-116 may implement a transmit path 400 for transmitting in the uplink to gNBs 101-103 and may implement a receive path 450 for receiving in the downlink from gNBs 101-103.

[0124] Each of the components in FIGS. 4A and 4B can be implemented using only hardware or using a combination of hardware and software / firmware. As a particular example, at least some of the components in FIGS. 4A and 4B may be implemented in software, while other components may be implemented by configurable hardware or a mixture of software and configurable hardware. For instance, the FFT block 470 and the IFFT block 415 may be implemented as configurable software algorithms, where the value of size N may be modified according to the implementation.

[0125] Furthermore, although described as using FFT and IFFT, this is by way of illustration only and should not be construed to limit the scope of the present disclosure. Other types of transforms, such as Discrete Fourier Transform (DFT) and Inverse Discrete Fourier Transform (IDFT) functions, can be used. It will be appreciated that the value of the variable N may be any integer number (such as 1, 2, 3, 4, or the like) for DFT and IDFT functions, while the value of the variable N may be any integer number that is a power of two (such as 1, 2, 4, 8, 16, or the like) for FFT and IFFT functions.

[0126] Although FIGS. 4A and 4B illustrate examples of wireless transmit and receive paths 400 and 450, respectively, various changes may be made to FIGS. 4A and 4B. For example, various components in FIGS. 4A and 4B can be combined, further subdivided, or omitted and additional components can be added according to particular needs. Also, FIGS. 4A and 4B are meant to illustrate examples of the types of transmit and receive paths that can be used in a wireless network. Any other suitable architectures can be used to support wireless communications in a wireless network.

[0127] FIG. 5 illustrates an example of a transmitter structure 500 for beamforming according to embodiments of the present disclosure. In certain embodiments, one or more of gNB 102 or UE 116 includes the transmitter structure 500. For example, one or more of antenna 205 and its associated systems or antenna 305 and its associated systems can be included in transmitter structure 500. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0128] In a hybrid analog-digital beamforming, analog beamforming corresponds to a 'dynamic / varying' virtualization of multiple antenna elements to obtain one antenna port (or antenna panel). For mmWave bands, although a number of antenna elements can be larger for a given form factor, a number of CSI-RS(Channel State Information RS) ports, that can correspond to the number of digitally precoded ports, can be limited due to hardware constraints (such as the feasibility to install a large number of analog-to-digital converters (ADCs) / digital-to-analog converters (DACs) at mmWave frequencies) as illustrated in FIG. 5. Then, one CSI-RS port can be mapped onto a large number of antenna elements that can be controlled by a bank of analog phase shifters 501. One CSI-RS port can then correspond to one sub-array which produces a narrow analog beam through analog beamforming 505. This analog beam can be configured to sweep across a wider range of angles 520 by varying the phase shifter bank across symbols or slots / subframes. The number of sub-arrays (equal to the number of RF chains) is the same as the number of CSI-RS ports NCSI-PORT. A digital beamforming unit 510 performs a linear combination across NCSI-PORTanalog beams to further increase a precoding gain. While analog beams are wideband (hence not frequency-selective), digital precoding can be varied across frequency sub-bands or resource blocks. Receiver operation can be conceived analogously.

[0129] Since the transmitter structure 500 of FIG. 5 utilizes multiple analog beams for transmission and reception (wherein one or a small number of analog beams are selected out of a large number, for instance, after a training duration that is occasionally or periodically performed), the term “multi-beam operation” is used to refer to the overall system aspect. This includes, for the purpose of illustration, indicating the assigned DL or UL TX beam (also termed “beam indication”), measuring at least one reference signal for calculating and performing beam reporting (also termed “beam measurement” and “beam reporting”, respectively), and receiving a DL or UL transmission via a selection of a corresponding RX beam. The system of FIG. 5 is also applicable to higher frequency bands such as >52.6GHz (also termed frequency range 4 or FR4). In this case, the system can employ only analog beams. Due to the O2 absorption loss around 60 GHz frequency (~10 dB additional loss per 100 m distance), a larger number and narrower analog beams (hence a larger number of radiators in the array) are essential to compensate for the additional path loss.

[0130] A communication system includes a downlink (DL) that conveys signals from transmission points such as Base Stations (BSs) or NodeBs to User Equipments (UEs) and an UpLink (UL) that conveys signals from UEs to reception points such as NodeBs. A UE, also commonly referred to as a terminal or a mobile station, may be fixed or mobile and may be a cellular phone, a personal computer device, or an automated device. An eNodeB, which is generally a fixed station, may also be referred to as an access point or other equivalent terminology. For LTE systems, a NodeB is often referred as an eNodeB.

[0131] In a communication system, such as LTE, DL signals can include data signals conveying information content, control signals conveying DL Control Information (DCI), and Reference Signals (RS) that are also known as pilot signals. An eNodeB transmits data information through a Physical DL Shared Channel (PDSCH). An eNodeB transmits DCI through a Physical DL Control Channel (PDCCH) or an Enhanced PDCCH (EPDCCH) - see also REF 3. An eNodeB transmits acknowledgement information in response to data Transport Block (TB) transmission from a UE in a Physical Hybrid ARQ Indicator Channel (PHICH). An eNodeB transmits one or more of multiple types of RS including a UE-Common RS (CRS), a Channel State Information RS (CSI-RS), or a DeModulation RS (DMRS). A CRS is transmitted over a DL system BandWidth (BW) and can be used by UEs to obtain a channel estimate to demodulate data or control information or to perform measurements. To reduce CRS overhead, an eNodeB may transmit a CSI-RS with a smaller density in the time and / or frequency domain than a CRS. DMRS can be transmitted only in the BW of a respective PDSCH or EPDCCH and a UE can use the DMRS to demodulate data or control information in a PDSCH or an EPDCCH, respectively. A transmission time interval for DL channels is referred to as a subframe (or slot) and can have, for example, duration of 1 millisecond.

[0132] DL signals also include transmission of a logical channel that carries system control information. A BCCH is mapped to either a transport channel referred to as a Broadcast Channel (BCH) when it conveys a Master Information Block (MIB) or to a DL Shared Channel (DL-SCH) when it conveys a System Information Block (SIB) - see also REF3 and REF 5. Most system information is included in different SIBs that are transmitted using DL-SCH. A presence of system information on a DL-SCH in a subframe (or slot) can be indicated by a transmission of a corresponding PDCCH conveying a codeword with a CRC scrambled with a special System Information RNTI (SI-RNTI). Alternatively, scheduling information for a SIB transmission can be provided in an earlier SIB and scheduling information for the first SIB (SIB-1) can be provided by the MIB.

[0133] DL resource allocation is performed in a unit of subframe (or slot) and a group of Physical resource blocks (PRBs). A transmission BW includes frequency resource units referred to as Resource Blocks (RBs). Each RB includes sub-carriers, or Resource Elements (REs), such as 12 REs. A unit of one RB over one subframe (or slot) is referred to as a PRB. A UE can be allocated RBs for a total of REs for the PDSCH transmission BW.

[0134] UL signals can include data signals conveying data information, control signals conveying UL Control Information (UCI), and UL RS. UL RS includes DMRS and Sounding RS (SRS). A UE transmits DMRS only in a BW of a respective PUSCH or PUCCH. An eNodeB can use a DMRS to demodulate data signals or UCI signals. A UE transmits SRS to provide an eNodeB with an UL CSI. A UE transmits data information or UCI through a respective Physical UL Shared CHannel (PUSCH) or a Physical UL Control CHannel (PUCCH). If a UE needs to transmit data information and UCI in a same UL subframe (or slot), it may multiplex both in a PUSCH. UCI includes Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) information, indicating correct (ACK) or incorrect (NACK) detection for a data TB in a PDSCH or absence of a PDCCH detection (DTX), Scheduling Request (SR) indicating whether a UE has data in its buffer, Rank Indicator (RI), and Channel State Information (CSI) enabling an eNodeB to perform link adaptation for PDSCH transmissions to a UE. HARQ-ACK information is also transmitted by a UE in response to a detection of a PDCCH / EPDCCH indicating a release of semi-persistently scheduled PDSCH (see also REF 3).

[0135] An UL subframe (or slot) includes two slots. Each slot includes symbols for transmitting data information, UCI, DMRS, or SRS. A frequency resource unit of an UL system BW is a RB. A UE is allocated RBs for a total of REs for a transmission BW. For a PUCCH, =1. A last subframe (or slot) symbol can be used to multiplex SRS transmissions from one or more UEs. A number of subframe (or slot) symbols that are available for data / UCI / DMRS transmission is , where =1 if a last subframe (or slot) symbol is used to transmit SRS and =0 otherwise.

[0136] FIG. 6 illustrates an example of a transmitter structure 600 for PDSCH in a subframe according to embodiments of the present disclosure. For example, transmitter structure 600 can be implemented in gNB 102 of FIG. 1. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0137] As illustrated in FIG. 6, information bits 610 are encoded by encoder 620, such as a turbo encoder, and modulated by modulator 630, for example using Quadrature Phase Shift Keying (QPSK) modulation. A Serial to Parallel (S / P) converter 640 generates M modulation symbols that are subsequently provided to a mapper 650 to be mapped to REs selected by a transmission BW selection unit 655 for an assigned PDSCH transmission BW, unit 660 applies an Inverse Fast Fourier Transform (IFFT), the output is then serialized by a Parallel to Serial (P / S) converter 670 to create a time domain signal, filtering is applied by filter 680, and a signal transmitted 690. Additional functionalities, such as data scrambling, cyclic prefix insertion, time windowing, interleaving, and others are well known in the art and are not shown for brevity.

[0138] FIG. 7 illustrates an example of a receiver structure 700 for PDSCH in a subframe according to embodiments of the present disclosure. For example, receiver structure 700 can be implemented by any of the UEs 111-116 of FIG. 1. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0139] With reference to FIG. 7, a received signal 710 is filtered by filter 720, REs 730 for an assigned reception BW are selected by BW selector 735, unit 740 applies a Fast Fourier Transform (FFT), and an output is serialized by a parallel-to-serial converter 750. Subsequently, a demodulator 760 coherently demodulates data symbols by applying a channel estimate obtained from a DMRS or a CRS (not shown), and a decoder 770, such as a turbo decoder, decodes the demodulated data to provide an estimate of the information data bits 780. Additional functionalities such as time-windowing, cyclic prefix removal, de-scrambling, channel estimation, and de-interleaving are not shown for brevity.

[0140] FIG. 8 illustrates an example of a transmitter structure 800 for PUSCH in a subframe according to embodiments of the present disclosure. For example, transmitter structure 800 can be implemented in gNB 103 of FIG. 1. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0141] As illustrated in FIG. 8, information data bits 810 are encoded by encoder 820, such as a turbo encoder, and modulated by modulator 830. A Discrete Fourier Transform (DFT) unit 840 applies a DFT on the modulated data bits, REs 850 corresponding to an assigned PUSCH transmission BW are selected by transmission BW selection unit 855, unit 860 applies an IFFT and, after a cyclic prefix insertion (not shown), filtering is applied by filter 870 and a signal transmitted 880.

[0142] FIG. 9 illustrates an example of a receiver structure 900 for a PUSCH in a subframe according to embodiments of the present disclosure; For example, receiver structure 900 can be implemented by the UE 116 of FIG. 3. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0143] As illustrated in FIG. 9, a received signal 910 is filtered by filter 920. Subsequently, after a cyclic prefix is removed (not shown), unit 930 applies a FFT, REs 940 corresponding to an assigned PUSCH reception BW are selected by a reception BW selector 945, unit 950 applies an Inverse DFT (IDFT), a demodulator 960 coherently demodulates data symbols by applying a channel estimate obtained from a DMRS (not shown), a decoder 970, such as a turbo decoder, decodes the demodulated data to provide an estimate of the information data bits 980.

[0144] There are two types of frequency range (FR) defined in 3GPP 5G NR specifications. The sub-6 GHz range is called frequency range 1 (FR1) and millimeter wave range is called frequency range 2 (FR2). An example of the frequency range for FR1 and FR2 is shown herein.

[0145]

[0146] For MIMO in FR1, up to 32 CSI-RS antenna ports is supported, and in FR2, up to 8 CSI-RS antenna ports is supported. In next generation cellular standards (e.g., 6G), in addition to FR1 and FR2, new carrier frequency bands can be evaluated, e.g., FR4 (>52.6GHz), terahertz (>100GHz) and upper mid-band (10-15GHz). The number of CSI-RS ports that can be supported for these new bands is likely to be different from FR1 and FR2. In particular, for 10-15GHz band, the max number of CSI-RS antenna ports is likely to be more than FR1, due to smaller antenna form factors, and feasibility of fully digital beamforming (as in FR1) at these frequencies. For instance, the number of CSI-RS antenna ports can grow up to 128. Besides, the NW(network) (e.g., the network 130) deployment / topology at these frequencies is also expected to be denser / distributed, for example, antenna ports distributed at multiple (non-co-located, hence geographically separated) TRPs within a cellular region can be the main scenario of interest, due to which the number of CSI-RS antenna ports for MIMO can be even larger (e.g., up to 256).

[0147] A (spatial or digital) precoding / beamforming can be used across these large number of antenna ports in order to achieve MIMO gains. Depending on the carrier frequency, and the feasibility of radio RF / hardware (HW)-related components, the (spatial) precoding / beamforming can be fully digital or hybrid analog-digital. In fully digital beamforming, there can be one-to-one mapping between an antenna port and an antenna element, or a 'static / fixed' virtualization of multiple antenna elements to one antenna port can be used. Each antenna port can be digitally controlled. Hence, a spatial multiplexing across antenna ports is provided.

[0148] In a wireless communication system, MIMO is often identified as key feature in order to achieve high system throughput requirements. One of the key components of a MIMO transmission scheme is the accurate CSI acquisition at the eNB (or gNB) (or TRP). For multi-user MIMO (MU-MIMO), in particular, the availability of accurate CSI is essential in order to guarantee high MU performance. For time division duplexing (TDD) systems, the CSI can be acquired using the SRS transmission relying on the channel reciprocity. For frequency division duplexing (FDD) systems, on the other hand, it can be acquired using the CSI-RS transmission from eNB (or gNB), and CSI acquisition and feedback from UE. In common FDD systems, the CSI feedback framework is 'implicit' in the form of channel quality indicator (CQI) / precoding matrix indicator (PMI) / rank indicator (RI) (also CSI reference signal identity (CRI) and layer identity (LI)) derived from a codebook implying SU transmission from eNB (or gNB).

[0149] In 5G or NR systems [REF7, REF8], the above-mentioned "implicit" CSI reporting paradigm from LTE is also supported and referred to as Type I CSI reporting. In addition, a high-resolution CSI reporting, referred to as Type II CSI reporting, is also supported in Release 15 specification to provide more accurate CSI information to gNB for use cases such as high-order MU-MIMO. However, embodiments of the present disclosure recognize the overhead of Type II CSI reporting can be an issue in practical UE implementations. One approach to reduce Type II CSI overhead is based on frequency domain (FD) compression. In Rel. 16 NR, DFT-based FD compression of the Type II CSI has been supported (referred to as Rel. 16 enhanced Type II codebook in REF8). Some of the key components for this feature includes (a) spatial domain (SD) basis , (b) FD basis , and (c) coefficients 　 that linearly combine SD and FD basis. In a non-reciprocal FDD system, a complete CSI (comprising all components) needs to be reported by the UE. However, when reciprocity or partial reciprocity does exist between UL and DL, then some of the CSI components can be obtained based on the UL channel estimated using SRS transmission from the UE. In Rel. 16 NR, the DFT-based FD compression is extended to this partial reciprocity case (referred to as Rel. 16 enhanced Type II port selection codebook in REF8), wherein the DFT-based SD basis in is replaced with SD CSI-RS port selection, i.e., L out of CSI-RS ports are selected (the selection is common for the two antenna polarizations or two halves of the CSI-RS ports). The CSI-RS ports in this case are beamformed in SD (assuming UL-DL channel reciprocity in angular domain), and the beamforming information can be obtained at the gNB based on UL channel estimated using SRS measurements.

[0150] In Rel. 17 NR, CSI reporting has been enhanced to support the following:

[0151] -Further enhanced Type II port selection codebook: it has been known in the literature that UL-DL channel reciprocity can exist in both angular and delay domains if the UL-DL duplexing distance is small. Since delay in time domain transforms (or closely related to) basis vectors in frequency domain (FD), the Rel. 16 enhanced Type II port selection can be further extended to both angular and delay domains (or SD and FD). In particular, the DFT-based SD basis in and DFT-based FD basis in can be replaced with SD and FD port selection, i.e., L CSI-RS ports are selected in SD or / and M ports are selected in FD. The CSI-RS ports in this case are beamformed in SD (assuming UL-DL channel reciprocity in angular domain) or / and FD (assuming UL-DL channel reciprocity in delay / frequency domain), and the corresponding SD or / and FD beamforming information can be obtained at the gNB based on UL channel estimated using SRS measurements. In Rel. 17, such a codebook is supported (which is referred to as Rel. 17 further enhanced Type II port selection codebook in REF8).

[0152] - Non-coherent joint transmission (NCJT) CSI reporting: When the UE can communicate with multiple TRPs that are distributed at different locations in space (e.g., within a cell), the CSI reporting can correspond to a single TRP hypothesis (i.e., CSI reporting for one of the multiple TRPs), or multi-TRP hypothesis (i.e., CSI reporting for at least two of the multiple TRPs). The CSI reporting for both single TRP and multi-TRP hypotheses are supported in Rel. 17. However, the multi-TRP CSI reporting assume a non-coherent joint transmission (NCJT), i.e., a layer (and precoder) of the transmission is restricted to be transmitted from only one TRP.

[0153] In Rel. 18 NR MIMO, the following CSI enhancements are further provided targeting two use cases (coherent joint transmission from multiple TRPs, and high / medium velocity UEs):

[0154] -Enhancements of CSI acquisition for Coherent-JT targeting FR1 and up to 4 TRPs, assuming ideal backhaul and synchronization as well as the same number of antenna ports across TRPs, as follows:

[0155] --Rel-16 / 17 Type-II codebook refinement for CJT mTRP targeting FDD and its associated CSI reporting, taking into account throughput-overhead trade-off.

[0156] -CSI reporting enhancement for high / medium UE velocities by exploiting time-domain correlation / Doppler-domain information to assist DL precoding, targeting FR1, as follows:

[0157] --Rel-16 / 17 Type-II codebook refinement, without modification to the spatial and frequency domain basis.

[0158] --UE reporting of time-domain channel properties measured via CSI-RS for tracking.

[0159] Although Rel-18 CJT CSI can support up to 128 antenna ports by configuring 4 CSI-RS resources each with 32 antenna ports, there is another interest arising to support up to 128 antenna ports using Type-I CSI, which requires smaller feedback overhead than Rel-18 CJT CSI. Currently, a single CSI-RS resource can support up to 32 antenna ports for Type-I single-panel (SP) and multi-panel (MP) CSI. By using multiple CSI-RS resources for Type-I CSI, it is allowed to configure up to 64 antenna ports according to one of the following two schemes:

[0160] -Two CSI-RS resources each with 32 antenna ports for Rel-17 NCJT (which is Type-I CSI-based).

[0161] -8 CSI-RS resources each with 8 antenna ports for Type-I SP CSI or Type-I MP CSI.

[0162] However, both of the schemes do not offer CSI feedback associated with the entire channel of 64 antenna ports, but are designed for specific use cases, 1) NCJT from two TRP, and 2) one CSI-RS resource selection and reporting associated with the selected CSI-RS resource, respectively. Hence, embodiments of the present disclosure recognize Type-I CSI with more than 32 antenna ports is limited in terms of use cases, and needs some enhancement.

[0163] In next generation MIMO systems, the number of antenna ports is expected to increase further (e.g., up to 256), for example, for carrier frequencies in upper mid-band (10-15GHz); the NW deployments are likely to be denser / more distributed (when compared with 5G NR); and the system is expected to work seamlessly even in challenging scenarios such as medium-high (e.g., 120kmph) speed UEs, 'higher-order) multi-user MIMO.

[0164] Similar to common (Rel.15 / 18 NR) both low-resolution (aka Type I) and high-resolution (aka Type II) CSI reporting for the distributed systems mentioned herein are needed and beneficial depending on use cases and scenarios. Unlike the common, however, it is preferable to have a common framework or components between the two CSI reporting settings, in order to have a simple, future-proof, and scalable solution, thereby making it more feasible in real deployments.

[0165] The present disclosure relates to a CSI reporting framework. In particular, it relates to the CSI reporting based on a low-resolution (or Type I) codebook comprising spatial-, frequency- and time- (Doppler-) domain components for a mTRP CJT with distributed antenna structure (DMIMO). Aspects include:

[0166] -Subsampling techniques to reduce CSI feedback overhead for low-resolution CSI reporting.

[0167] -Configuring subsampling techniques by NW.

[0168] -Subsampling techniques determined by a fixed rule or by UE.

[0169] Aspects, features, and advantages of the present disclosure are readily apparent from the following detailed description, simply by illustrating a number of particular embodiments and implementations, including the best mode contemplated for carrying out the present disclosure. Embodiments of the present disclosure also capable of other and different embodiments, and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. Embodiments of the present disclosure are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.

[0170] In the following, for brevity, both FDD and TDD are considered as the duplex method for both DL and UL signaling.

[0171] Although exemplary descriptions and embodiments to follow assume orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA), the present disclosure can be extended to other OFDM-based transmission waveforms or multiple access schemes such as filtered OFDM (F-OFDM).

[0172] The present disclosure covers several components which can be used in conjunction or in combination with one another or can operate as standalone schemes.

[0173] Each of the following components and embodiments are applicable for UL transmission with CP-OFDM (cyclic prefix OFDM) waveform as well as DFT-SOFDM (DFT-spread OFDM) and SC-FDMA (single-carrier FDMA) waveforms. Furthermore, each of the following components and embodiments are applicable for UL transmission when the scheduling unit in time is either one subframe (which can include one or multiple slots) or one slot.

[0174] In the present disclosure, the frequency resolution (reporting granularity) and span (reporting bandwidth) of CSI reporting can be defined in terms of frequency “subbands” and “CSI reporting band” (CRB), respectively.

[0175] A subband for CSI reporting is defined as a set of contiguous PRBs which represents the smallest frequency unit for CSI reporting. The number of PRBs in a subband can be fixed for a given value of DL system bandwidth, configured either semi-statically via higher-layer / RRC signaling, or dynamically via L1 DL control signaling or MAC control element (MAC CE). The number of PRBs in a subband can be included in CSI reporting setting.

[0176] “CSI reporting band” is defined as a set / collection of subbands, either contiguous or non-contiguous, wherein CSI reporting is performed. For example, CSI reporting band can include each of the subbands within the DL system bandwidth. This can also be termed “full-band”. Alternatively, CSI reporting band can include only a collection of subbands within the DL system bandwidth. This can also be termed “partial band”.

[0177] The term "CSI reporting band" is used only as an example for representing a function. Other terms such as "CSI reporting subband set" or "CSI reporting bandwidth" or bandwidth part (BWP) can also be used.

[0178] In terms of UE configuration, a UE can be configured with at least one CSI reporting band. This configuration can be semi-static (via higher-layer signaling or RRC) or dynamic (via MAC CE or L1 DL control signaling). When configured with multiple (N) CSI reporting bands (e.g., via RRC signaling), a UE can report CSI associated with n ≤ N CSI reporting bands. For instance, >6GHz, large system bandwidth may require multiple CSI reporting bands. The value of n can either be configured semi-statically (via higher-layer signaling or RRC) or dynamically (via MAC CE or L1 DL control signaling). Alternatively, the UE can report a recommended value of n via an UL channel.

[0179] Therefore, CSI parameter frequency granularity can be defined per CSI reporting band as follows. A CSI parameter is configured with "single" reporting for the CSI reporting band with Mnsubbands when one CSI parameter for each of the Mnsubbands within the CSI reporting band. A CSI parameter is configured with "subband" for the CSI reporting band with Mnsubbands when one CSI parameter is reported for each of the Mnsubbands within the CSI reporting band.

[0180] FIG. 10 illustrates a diagram of an antenna port layout 1000 according to embodiments of the present disclosure. For example, antenna port layout 1000 of an antenna port layout can be implemented by the BS 102 of FIG. 2. This example is for illustration only and can be used without departing from the scope of the present disclosure.

[0181] With reference to FIG. 10, N1and N2are the number of antenna ports with the same polarization in the first and second dimensions, respectively. For 2D antenna port layouts, N1> 1, N2> 1, and for 1D antenna port layouts N1> 1 and N2= 1 (or N1= 1 and N2> 1). For a single-polarized (or co-polarized) antenna port layout, the total number of antenna ports is . And, for a dual-polarized antenna port layout, the total number of antenna ports is . "X" represents two antenna polarizations. In this disclosure, the term "polarization" refers to a group of antenna ports with the same polarization. For example, antenna ports comprise a first antenna polarization, and antenna ports comprise a second antenna polarization, where PCSIRSis a number of CSI-RS antenna ports and X is a starting antenna port number (e.g., X=3000, then antenna ports are 3000, 3001, 3002, …). Dual-polarized antenna layouts are implied in this disclosure. The embodiments (and examples) in this disclosure however are general and are applicable to single-polarized antenna layouts as well.

[0182] Let Ngbe a number of antenna groups (AGs). With reference to FIG. 10, when there are multiple antenna groups (Ng＞1), each group (g∈{1,…,Ng}) comprises dual-polarized antenna ports with N1,gand N2,gports in two dimensions. Note that the antenna port layouts may be the same (N1,g=N1and N2,g=N2) in different antenna groups, or they can be different across antenna groups. For group g, the number of antenna ports is (for co-polarized or dual-polarized respectively).

[0183] In one example, an antenna group corresponds to an antenna panel. In one example, an antenna group corresponds to a TRP. In one example, an antenna group corresponds to a remote radio head (RRH). In one example, an antenna group corresponds to CSI-RS antenna ports of a NZP CSI-RS resource. In one example, an antenna group corresponds to a subset of CSI-RS antenna ports of a NZP CSI-RS resource (comprising multiple antenna groups). In one example, an antenna group corresponds to CSI-RS antenna ports of multiple NZP CSI-RS resources (e.g., comprising a CSI-RS resource set).

[0184] In one example, an antenna group corresponds to a reconfigurable intelligent surface (RIS) in which the antenna group can be (re-)configured more dynamically (e.g., via MAC CE or / and DCI). For example, the number of antenna ports associated with the antenna group can be changed dynamically.

[0185] FIG. 11 illustrates examples co-located and distributed antenna groups AGs 1100 serving a moving UE according to embodiments of the present disclosure. For example, the co-located and distributed AGs 1100 implemented by any of the BSs 101-103 of FIG. 1. This example is for illustration only and can be used without departing from the scope of the present disclosure.

[0186] In one example scenario, multiple AGs can be co-located or distributed, and can serve static (non-mobile) or moving UEs. With reference to FIG. 11, an illustration of AGs serving a moving UE is shown. While the UE moves from a location A to another location B, the UE measures the channel, e.g., via NZP CSI-RS resources, (may also measure the interference, e.g., via CSI interference measurement (CSI-IM) resources or CSI-RS resources for interference measurement), uses the measurement to determine / report CSI considering joint transmission from multiple AGs. The reported CSI can be based on a codebook. The codebook can include components considering multiple AGs, and frequency / delay-domain channel profile and time / Doppler-domain channel profile.

[0187] In one example, the antenna architecture of the MIMO system is structured. For example, the antenna structure at each AG is dual-polarized (single or multi-panel as shown in FIG. 10). The antenna structure at each AG can be the same. Or the antenna structure at an AG can be different from another AG. Likewise, the number of ports at each AG can be the same. Or the number of ports at one AG can be different from another AG.

[0188] In another example, the antenna architecture of the MIMO system is unstructured. For example, the antenna structure at one AG can be different from another AG.

[0189] A structured antenna architecture in the rest of the disclosure is assumed. For simplicity, it is expected that each AG is equivalent to a panel (cf. FIG. 10), although, an AG can have multiple panels in practice. The disclosure however is not restrictive to a single panel expectation at each AG, and extends (covers) the case when an AG has multiple antenna panels.

[0190] In various embodiments, an AG constitutes (or corresponds to or is equivalent to) at least one of the following:

[0191] -In one example, an AG corresponds to a TRP.

[0192] -In one example, an AG corresponds to a CSI-RS resource. A UE is configured with K=Ng>1 non-zero-power (NZP) CSI-RS resources, and a CSI reporting is configured to be across multiple CSI-RS resources. This is similar to Class B, K > 1 configuration in Rel. 14 LTE. The K NZP CSI-RS resources can belong to a CSI-RS resource set or multiple CSI-RS resource sets (e.g., K resource sets each comprising one CSI-RS resource). The details are as explained in this disclosure herein.

[0193] -In one example, an AG corresponds to a CSI-RS resource group, where a group comprises one or multiple NZP CSI-RS resources. A UE is configured with K≥Ng>1 non-zero-power (NZP) CSI-RS resources, and a CSI reporting is configured to be across multiple CSI-RS resources from resource groups. This is similar to Class B, K > 1 configuration in Rel. 14 LTE. The K NZP CSI-RS resources can belong to a CSI-RS resource set or multiple CSI-RS resource sets (e.g., K resource sets each comprising one CSI-RS resource). The details are as explained in this disclosure herein. In particular, the K CSI-RS resources can be partitioned into Ngresource groups. The information about the resource grouping can be provided together with the CSI-RS resource setting / configuration, or with the CSI reporting setting / configuration, or with the CSI-RS resource configuration.

[0194] -In one example, an AG corresponds to a subset (or a group) of CSI-RS ports. A UE is configured with at least one NZP CSI-RS resource comprising (or associated with) CSI-RS ports that can be grouped (or partitioned) multiple subsets / groups / parts of antenna ports, each corresponding to (or constituting) an AG. The information about the subsets of ports or grouping of ports can be provided together with the CSI-RS resource setting / configuration, or with the CSI reporting setting / configuration, or with the CSI-RS resource configuration.

[0195] -In one example, an AG corresponds to one or more examples described herein depending on a configuration. For example, this configuration can be explicit via a parameter (e.g., an RRC parameter). Or it can be implicit.

[0196] --In one example, when implicit, it could be based on the value of K. For example, when K>1 CSI-RS resources, an AG corresponds to one or more examples described herein. For example, when K=1 CSI-RS resource, an AG corresponds to one or more examples described herein.

[0197] --In another example, the configuration could be based on the configured codebook. For example, an AG corresponds to a CSI-RS resource or resource group according to one or more examples described herein when the codebook corresponds to a decoupled codebook (modular or separate codebook for each AG), and an AG corresponds to a subset (or a group) of CSI-RS ports when codebook corresponds to a coupled (joint or coherent) codebook (one joint codebook across AGs).

[0198] In one example, when AG maps (or corresponds to) a CSI-RS resource or resource group, and a UE can select a subset of AGs (resources or resource groups) and report the CSI for the selected AGs (resources or resource groups), the selected AGs can be reported via an indicator. For example, the indicator can be a CRI or a PMI (component) or a new indicator.

[0199] In one example, when AG maps (or corresponds to) a CSI-RS port group, and a UE can select a subset of AGs (port groups) and report the CSI for the selected AGs (port groups), the selected AGs can be reported via an indicator. For example, the indicator can be a CRI or a PMI (component) or a new indicator.

[0200] In one example, when multiple (K>1) CSI-RS resources are configured for NgAGs, a decoupled (modular) codebook is used / configured, and when a single (K=1) CSI-RS resource for NgAGs, a joint codebook is used / configured.

[0201] FIG. 12 illustrates an example of a timeline 1200 for a UE to receive NZP CSI-RS resource(s) bursts according to embodiments of the present disclosure. For example, timeline 1200 for a UE to receive NZP CSI-RS resource(s) bursts can be received by the UE 116 of FIG. 3. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0202] In one embodiment, with reference to FIG. 12, a UE is configured to receive a burst of non-zero power (NZP) CSI-RS resource(s), referred to as CSI-RS burst for brevity, within B time slots comprising a measurement window, where B≥1. The B time slots can be according to at least one of the following examples.

[0203] -In one example, the B time slots are evenly / uniformly spaced with an inter-slot spacing d.

[0204] -In one example, the B time slots can be non-uniformly spaced with inter-slot spacing e1=d1, e2=d2-d1, e3=d3-d2,…, so on, where ei≠ejfor at least one pair (i,j) with i≠j.

[0205] The UE (e.g., the UE 116) receives the CSI-RS burst, estimates the B instances of the DL channel measurements, and uses the channel estimates to obtain the Doppler component(s) of the DL channel. The CSI-RS burst can be linked to (or associated with) a single CSI reporting setting (e.g., via higher layer parameter CSI-ReportConfig), wherein the corresponding CSI report includes an information about the Doppler component(s) of the DL channel.

[0206] Let be the DL channel estimate based on the CSI-RS resource(s) received in time slot . When the DL channel estimate in slot t is a matrix of size , then , where , and are number of receive (Rx) antennae at the UE, number of CSI-RS ports measured by the UE, and number of subcarriers in frequency band of the CSI-RS burst, respectively. The notation is used to denote the vectorization operation wherein the matrix X is transformed into a vector by concatenating the elements of the matrix in an order, for example, 1 → 2 → 3 → and so on, implying that the concatenation starts from the first dimension, then moves second dimension, and continues until the last dimension. Let be a concatenated DL channel. The Doppler component(s) of the DL channel can be obtained based on . For example, can be represented as where is a Doppler domain (DD) basis matrix whose columns comprise basis vectors, is a coefficient matrix whose columns comprise coefficient vectors, and N<B is the number of DD basis vectors. Since the columns of are likely to be correlated, a DD compression can be achieved when the value of N is small (compared to the value of B). In this example, the Doppler component(s) of the channel is represented by the DD basis matrix and the coefficient matrix C.

[0207] When there are multiple TRPs / RRHs (NTRP>1), the UE can be configured to measure the CSI-RS burst(s) according to at least one of the following examples.

[0208] In one example, the UE is configured to measure NTRPCSI-RS bursts, one from each TRP / RRH. The NTRPCSI-RS bursts can be overlapping in time (i.e., measured in same time slots). Or they can be staggered in time (i.e., measured in different time slots). Whether the bursts are overlapping or staggered can be determined based on configuration. It can also depend on the total number of CSI-RS ports across RRHs / TRPs. When the total number of ports is small (e.g., <= 32), they can overlap, otherwise (>32), they are staggered. The number of time instances B can be the same for each of the NTRPbursts. Or the number B can be the same or different across bursts (or TRPs / RRHs).

[0209] -In one example, each CSI-RS burst corresponds to a semi-persistent (SP) CSI-RS resource. The SP CSI-RS resource can be activated or / and deactivated based on a MAC CE or / and DCI based signaling. Additional details can be as described in the U.S. Patent Application No. 17 / 689,838 filed March 8, 2022 (the ’838 Application), which is incorporated by reference in its entirety.

[0210] -In one example, each CSI-RS burst corresponds to a group of B≥1 aperiodic (Ap) CSI-RS resources. The Ap-CSI-RS resources can be triggered via a DCI with slot offsets such that they can be measured in B different time slots. The rest of the details can be as described in the ’838 Application.

[0211] -In one example, each CSI-RS burst corresponds to a periodic (P) CSI-RS resource. The P-CSI-RS resource can be configured via higher layer. The first measurement instance (time slot) and the measurement window of the CSI-RS burst (from the P-CSI-RS resource) can be fixed or configured. The rest of the details can be as described in the ’838 Application.

[0212] -In one example, a CSI-RS burst can either be a P-CSI-RS, or SP-CSI-RS or Ap-CSI-RS resource.

[0213] -In one example, the time-domain behavior (P, SP, or Ap) of NTRPCSI-RS bursts is the same.

[0214] -In one example, the time-domain behavior of NTRPCSI-RS bursts can be the same or different.

[0215] In one example, the UE (such as UE 116) is configured to measure K≥NTRPCSI-RS bursts, where and Kris a number of CSI-RS bursts associated with RRH / TRP r, where r∈{1,…,NTRP}. Each CSI-RS burst is according to one or more examples described herein. When Kr>1, multiple CSI-RS bursts are linked to (or associated with) a CSI reporting setting, i.e., the UE receives the NrCSI-RS bursts, estimates the DL channels, and obtains the Doppler component(s) of the channel using each of the NrCSI-RS bursts. The rest of the details can be as described in the '838 Application.

[0216] In one example, the UE is configured to measure one CSI-RS burst across each of the NTRPTRPs / RRHs. Let P be a number of CSI-RS ports associated with the NZP CSI-RS resource measured via the CSI-RS burst. The CSI-RS burst is according to one or more examples described herein. The total of P ports can be divided into NTRPgroups / subsets of ports and one group / subset of ports is associated with (or corresponds to) a TRP / RRH. Then, and Pris a number of CSI-RS ports in the group / subset of ports associated with RRH / TRP r.

[0217] -In one example, in each of the B time instances, a UE is configured to measure each groups / subsets of ports, i.e., in each time instance within the burst, the UE measures each of P ports (or NTRPgroups / subsets of ports).

[0218] -In one example, a UE is configured to measure subsets / groups of ports across multiple time instances, i.e., in each time instance within the burst, the UE measures a subset of P ports or a subset of groups of ports (RRHs / TRPs).

[0219] -In one example, in each time instance, the UE measures only one group / subset of ports (1 TRP per time instance). In this case, or , where C is a number of measurement instances for each TRP / RRH.

[0220] -In one example, the UE is configured to measure one half of the port groups in a time instance, and the remaining half in another time instance.

[0221] -In one example, the two time instances can be consecutive, for example, the UE measures one half of port groups in even-numbered time instances, and the remaining half in the odd-numbered time instances.

[0222] -In one example, a first half of the time instances (e.g., 0,1,…, ) is configured to measure one half of the port groups, and the second half of the time instances (e.g., ,…B-1) is configured to measure the remaining half of the port groups.

[0223] In one example, the UE is configured to measure multiple CSI-RS bursts, where each burst is according to one or more examples described herein. Multiple CSI-RS bursts are linked to (or associated with) a CSI reporting setting, i.e., the UE receives multiple CSI-RS bursts, estimates the DL channels, and obtains the Doppler component(s) of the channel using each of multiple CSI-RS bursts.

[0224] Let N4be the length of the DD basis vectors { }, e.g., each basis vector is a length N4×1 column vector.

[0225] FIG. 13 illustrates examples of timelines 1300 for partitioned CSI-RS burst instances according to embodiments of the present disclosure. For example, timelines 1300 for partitioned CSI-RS burst instances can be received by the UE 113 of FIG. 1. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0226] In one embodiment, a UE is configured to determine a value of N4based on the value B (number of CSI-RS instances) in a CSI-RS burst and components across which the DD compression is performed, where each component corresponds to one or multiple time instances within the CSI-RS burst. In one example, N4is fixed (e.g., N4=B) or configured (e.g., via RRC or MAC CE or DCI) or reported by the UE (e.g., the UE 116) (as part of the CSI report). In one example, the B CSI-RS instances can be partitioned into sub-time (ST) units (instances), where each ST unit is defined as (up to) NSTcontiguous time instances in the CSI-RS burst. In this example, a component for the DD compression corresponds to a ST unit. With reference to FIG. 13, three examples of the ST units are shown. In the first example, each ST unit comprises NST=1 time instance in the CSI-RS burst. In the second example, each ST unit comprises NST=2 contiguous time instances in the CSI-RS burst. In the third example, each ST unit comprises NST=4 contiguous time instances in the CSI-RS burst.

[0227] The value of NSTcan be fixed (e.g., NST=1 or 2 or 4) or indicated to the UE (e.g., via higher layer RRC or MAC CE or DCI based signaling) or reported by the UE (e.g., as part of the CSI report). The value of NST(fixed or indicated or reported) can be subject to a UE capability reporting. The value of NSTcan also be dependent on the value of B (e.g., one value for a range of values for B and another value for another range of values for B).

[0228] When there are multiple TRPs / RRHs (NTRP>1), the UE can be configured to determine a value of N4according to at least one of the following examples.

[0229] -In one example, a value of N4is the same for each TRPs / RRHs.

[0230] -In one example, a value of N4can be the same or different across TRPs / RRHs.

[0231] FIG. 14 is an example of RB and SB partitions 1400 according to embodiments of the present disclosure. For example, the RB and SB partitions 1400 can be followed by the UE 116 of FIG. 3. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0232] In one embodiment, a UE is configured with J≥1 CSI-RS bursts (as illustrated herein) that occupy a frequency band and a time span (duration), wherein the frequency band comprises A RBs, and the time span comprises B time instances (of CSI-RS resource(s)). When J>1, the A RBs or / and B time instances can be aggregated across J CSI-RS bursts. In one example, the frequency band equals the CSI reporting band, and the time span equals the number of CSI-RS resource instances (across J CSI-RS bursts). Both can be configured to the UE (e.g., the UE 116) for a CSI reporting, which can be based on the DD compression.

[0233] The UE is further configured to partition (divide) the A RBs into subbands (SBs) or / and the B time instances into sub-times (STs). The partition of A RBs can be based on a SB size value NSB, which can be configured to the UE (cf. Table 5.2.1.4-2 of REF8). The partition of B time instances can be based either a ST size value NSTor an r value, as described in this disclosure. With reference to FIG. 14, RB0, RB1, …, RBA-1 comprise A RBs, T0,T1,…,TB-1comprise B time instances, the SB size NSB=4, and the ST size NST=2.

[0234] When there are multiple TRPs / RRHs (NTRP>1), the UE can be configured to determine subbands (SBs) or / and sub-times (STs) according to at least one of the following examples.

[0235] -In one example, both subbands (SBs) or / and sub-times (STs) are the same for each of the TRPs / RRHs.

[0236] -In one example, subbands (SBs) are the same for each TRPs / RRHs, but sub-times (STs) can be the same or different across RRHs / TRPs.

[0237] -In one example, sub-times (STs) are the same for each TRPs / RRHs, but subbands (SBs) can be the same or different across RRHs / TRPs.

[0238] -In one example, both sub-times (STs) and subbands (SBs) can be the same or different across RRHs / TRPs.

[0239] For illustration, the example where both SBs or / and STs are the same for each of the TRPs / RRHs is used in the description below.

[0240] The CSI reporting is based on channel measurements (based on CSI-RS bursts) in three-dimensions (3D): the first dimension corresponds to SD comprising PCSIRSCSI-RS antenna ports (in total across each of the NTRPRRHs / TRPs), the second dimension corresponds to FD comprising N3FD units (e.g., SB), and the third dimension corresponds to DD comprising N4DD units (e.g., ST). The 3D channel measurements can be compressed using basis vectors (or matrices) similar to the Rel. 16 enhanced Type II codebook. Let , , and respectively denote basis matrices whose columns comprise basis vectors for SD, FD, and DD.

[0241] In one embodiment, the DD compression (or DD component or basis) can be turned OFF / ON from the codebook. When turned OFF, can be fixed (hence not reported), e.g., =1 (scalar 1) or =[1,…,1] (all-one vector) or (all-one vector) or (identity matrix), where n is a scaling factor (e.g., n=N4) or , where is an index of a fixed DD basis vector . In one example, =0. In one example, when the DD basis vectors comprise an orthogonal DFT basis set, is a DD basis vector which corresponds to the DC component. When turned ON, (DD basis vectors) is reported.

[0242] -In one example, is turned OFF / ON via an explicit signaling, e.g., an explicit RRC parameter.

[0243] -In one example, is turned OFF / ON via a codebook parameter. For example, similar to M=1 in Rel.17, when N=1 is configured, is turned OFF, and when a value N>1 is configured, is turned ON. Here, N denotes a number of DD basis vectors comprising columns of .

[0244] -In one example, the UE reports whether the DD component is turned OFF (not reported) or ON (reported). This reporting can be via a dedicated parameter (e.g., new UCI / CSI parameter). Or this reporting can be via an existing parameter (e.g., PMI component). A two-part UCI (cf. Rel. 15 NR) can be reused wherein the information whether is turned OFF / ON is included in UCI part 1.

[0245] -In one example, is turned OFF / ON depending on the codebookType. When the codebookType is regular Type II codebook (similar to Rel 16 Type II codebook), is turned ON, and when the codebookType is Type II port selection codebook (similar to Rel 17 Type II codebook), is turned ON / OFF.

[0246] FIG. 15 illustrates an example of SD units, FD units, and TD units 1500 according to embodiments of the present disclosure. For example, the example SD units, FD units, and TD units 1500 can be utilized by any of the UEs 111-116 of FIG. 1. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0247] In one embodiment, a UE (e.g., the UE 116) is configured (e.g., via a higher layer CSI configuration information) with a CSI report, where the CSI report is based on a channel measurement (and interference measurement) and a codebook. When the CSI report is configured to be aperiodic, it is reported when triggered via a DCI field (e.g., a CSI request field) in a DCI.

[0248] The channel measurement can be based on K≥1 channel measurement resources (CMRs) that are transmitted from a plurality of spatial-domain (SD) units (e.g., a SD unit = a CSI-RS antenna port), and are measured via a plurality of frequency-domain (FD) units (e.g., a FD unit = one or more PRBs / SBs) and via either a time-domain (TD) unit or a plurality of TD units (e.g., a TD unit = one or more time slots). In one example, a CMR can be a NZP-CSI-RS resource.

[0249] The CSI report can be associated with the plurality of FD units and the plurality of TD units associated with the channel measurement. Alternatively, the CSI report can be associated with a second set of FD units (different from the plurality of FD units associated with the channel measurement) or / and a second set of TD units (different from the plurality of TD units associated with the channel measurement). In this later case, the UE (e.g., the UE 116), based on the channel measurement, can perform prediction (interpolation or extrapolation) in the second set of FD units or / and the second set of TD units associated with the CSI report.

[0250] With reference to FIG. 15, an illustration of the SD units (in 1stand 2ndantenna dimensions), FD units, and TD units is shown:

[0251] -The first dimension is associated with the 1st antenna port dimension and comprises N1units,

[0252] -The second dimension is associated with the 2nd antenna port dimension and comprises N2units,

[0253] -The third dimension is associated with the frequency dimension and comprises N3units, and

[0254] -The fourth dimension is associated with the time / Doppler dimension and comprises N4units.

[0255] Regarding SD units, the plurality of SD units can be associated with antenna ports (e.g., co-located at one site or distributed across multiple sites) comprising one or multiple antenna groups (i.e., Ng≥1), and dimensionalizes the spatial-domain profile of the channel measurement.

[0256] When K=1, there is one CMR comprising PCSIRSCSI-RS antenna ports.

[0257] -When Ng=1, there is one AG comprising PCSIRSports, and the CSI report is based on the channel measurement from the one AG.

[0258] -When Ng>1, there are multiple AGs, and the CSI report is based on the channel measurement from / across the multiple AGs.

[0259] When K>1, there are multiple CMRs, and the CSI report is based on the channel measurement across the multiple CMRs. In one example, a CMR corresponds to an AG (one-to-one mapping). In one example, multiple CMRs can correspond to an AG (many-to-one mapping).

[0260] In one example, when the PCSIRSantenna ports are co-located at one site, Ng=1. In one example, when the PCSIRSantenna ports are distributed (non-co-located) across multiple sites, Ng>1.

[0261] In one example, when the PCSIRSantenna ports are co-located at one site and within a single antenna panel, Ng=1. In one example, when the PCSIRSantenna ports are distributed across multiple antenna panels (can be co-located or non-co-located), Ng>1.

[0262] The value of Ngcan be configured, e.g., via higher layer RRC parameter. Or it can be indicated via a MAC CE. Or it can be provided via a DCI field.

[0263] Likewise, the value of K can be configured, e.g., via higher layer RRC parameter. Or it can be indicated via a MAC CE. Or it can be provided via a DCI field.

[0264] In one example, K=Ng=X. The value of X can be configured, e.g., via higher layer RRC parameter. Or it can be indicated via a MAC CE. Or it can be provided via a DCI field.

[0265] In one example, the value of K is determined based on the value of Ng. In one example, the value of Ngis determined based on the value of K.

[0266] Regarding FD units, the plurality of FD units can be associated with a frequency domain allocation of resources (e.g., one or multiple CSI reporting bands, each comprising multiple PRBs) and dimensionalizes the frequency (or delay)-domain profile of the channel measurement.

[0267] Regarding TD / DD units, the plurality of TD units can be associated with a time domain allocation of resources (e.g., one or multiple CSI reporting windows, each comprising multiple time slots) and dimensionalizes the time (or Doppler)-domain profile of the channel measurement.

[0268] Regarding SB size and BWP, in 5G NR, configurable subband sizes (for CQI) depend on a configured bandwidth part (BWP). As seen in the following table in [REF 8], one of two subband sizes can be configured for a given BWP.

[0269]

[0270] In one embodiment, configurable subband size for CQI, PMI, or another reporting quantity (e.g., 5G NR Rel-19 CJTC phase offset reporting or its 6G counterpart) K does not depend on a BWP. The subband size K can be configured from a set S.

[0271] In one example, S includes 1. In one example, S does not include 1.

[0272] In one example, S includes 2. In one example, S does not include 2.

[0273] In one example, S includes 3. In one example, S does not include 3.

[0274] In one example, S includes 4. In one example, S does not include 4.

[0275] In one example, S includes 5. In one example, S does not include 5.

[0276] In one example, S includes 6. In one example, S does not include 6.

[0277] In one example, S includes 7. In one example, S does not include 7.

[0278] In one example, S includes 8. In one example, S does not include 8.

[0279] In one example, S includes 9. In one example, S does not include 9.

[0280] In one example, S includes 10. In one example, S does not include 10.

[0281] In one example, S includes 16. In one example, S does not include 16.

[0282] In one example, S includes 32. In one example, S does not include 32.

[0283] In one example, S includes 64. In one example, S does not include 64.

[0284] In one example, S includes 128. In one example, S does not include 128.

[0285] In one example, S includes 256. In one example, S does not include 256.

[0286] In one example, S includes an element indicating 'wideband', where the element refers to WB reporting, i.e., one reporting quantity for a whole configured BWP. In one example, S does not include an element indicating 'wideband'.

[0287] In one example, S includes at least one of 1,2,4,8,16,64,128,256, and 'wideband'.

[0288] In one example, S includes a subset of 1,2,4,8,16,64,128,256, and 'wideband'.

[0289] In one example, a unit of an element in a set S is PRB or RB.

[0290] In one example, a unit of an element in a set S is subcarrier.

[0291] In one example, a set S can be according to at least one of the examples above or under one or more embodiments herein.

[0292] In one embodiment, a configurable SB size from a set S should not be larger than a configured BWP or should be less than or equal to a configured BWP.

[0293] In one example, a UE is not expected to be configured with a larger SB size than a configured BWP.

[0294] In one example, when a larger SB size than a configured BWP is configured for a UE, the UE regards it as wideband being configured.

[0295] In one embodiment, a maximum number of SBs that can be configured is specified as NSB,max, where NSB,maxis fixed to a value or subject to a UE capability, or configured by NW via higher-layer signaling, and a number of SBs can be determined as ceil . Here, ceil(x) refers to the smallest integer that equals to or is larger than x.

[0296] In one example, a UE is not expected to be configured with a SB size and a BWP that results in the number of SBs exceeding NSB,max.

[0297] In one example, when a SB size and a BWP are configured such that a number of SBs exceeding NSB,max, the UE regards the SB size as the largest SB size for the BWP that results in a number of SBs not exceeding NSB,max.

[0298] In one example, NSB,maxis fixed to a value, e.g., 18.

[0299] In one example, NSB,maxis fixed to a value, e.g., greater than 18.

[0300] In one example, NSB,maxis fixed to a value, e.g., smaller than 18.

[0301] In one example, NSB,maxdepends on CQI or PMI, or reporting quantity.

[0302] In one example, NSB,maxis subject to a UE capability. In one example, candidate values for the UE capability NSB,maxof include 18.

[0303] In one embodiment, there is no maximum number of SBs being specified. In this case, in one example, a UE can be configured with a SB size regardless of the maximum number of SBs.

[0304] In one embodiment, for either a first SB or a last SB, the SB size can be not the same as a configured SB size K. In one example, the SB size can be given by or correspond to remainder of .

[0305] In one embodiment, a SB size K is applied to both CQI and PMI, i.e., the numbers of SBs for CQI and PMI are the same, where the CQI and PMI indicate a reporting value(s) for each SB.

[0306] The CSI report includes an information about a precoding matrix (e.g., the information is an indicator such as PMI). The information about the precoding matrix comprises / includes at least two components (W1and W2). The first component (W1) includes a basis which corresponds to a set of basis entities. The second component (W2) includes

[0307] -For low-resolution (Type I), selection of a basis entity from the basis entities (per layer) and co-phasing across two polarizations.

[0308] -For high-resolution (Type II), combining coefficients which linearly combine the basis entities, i.e., the precoding matrix can be represented as a weighted summation over the basis entities, where the weights are the combining coefficients.

[0309] The first component W1is codebook-based. When the basis needs reporting (or configured to be reported), the codebook configured for the CSI report includes at least one component for reporting the basis W1. This component is similar to legacy (e.g., Type I and II codebooks in 5G NR) codebooks. However, since W1is decoupled from W2, the framework allows more options and parameterization for the W1basis as future upgrades when newer antenna types become available. The basis can be dictated by (or associated with) at least one of the spatial-domain profile, frequency (or delay)-domain profile, or time (Doppler)-domain profile of the channel measurement. Even though the number of CSI-RS antenna ports can be large (e.g., 256), the antenna ports are expected to have some antenna structure (e.g., similar to 2D active antenna array), hence the SD channel profile can be represented using SD basis entities, where the SD basis entities have dimension depending on the number of SD units (PCSIRSor or 2N1N2or N1N2). Likewise, the FD channel profile is likely to be correlated across FD units, and the DD / TD channel profile is also expected to have some correlation across DD / TD units (e.g., for low-medium speed UEs). Hence, FD and DD / TD channel profiles can be represented using FD and DD / TD basis entities, respectively, where their dimensions depend on the number of FD units (N3) and the number of DD / TD units (N4), respectively.

[0310] The second component (W2) is also codebook-based and is derived based on the channel measurement and W1. For instance, the channel measurement can be projected on to the basis W1and projected channel can be used to derive the W2components (coefficients), e.g., based on Type I or Type II codebooks in 5G NR.

[0311] In one example, the number of antenna ports across K CSI-RS resources is the same. For example, each of the K CSI-RS resources can be associated with 2N1N2antenna ports. In this case, the total number of antenna ports is PCSIRS,tot=2KN1N2.

[0312] In one example, the number of antenna ports across K CSI-RS resources can be the same or different. For example, each of the K CSI-RS resources can be associated with 2N1,rN2,rantenna ports. In this case, the total number of antenna ports is .

[0313] In port numbering scheme 1, the CSI-RS ports are numbered according to the order of (polarization p, NZP CSI-RS resource r) as CSI-RS ports of (p=0,r=1) followed by CSI-RS ports of (p=1,r=1), followed by CSI-RS ports of (p=0,r=2), followed by CSI-RS ports of (p=1,r=2),…, ,followed by CSI-RS ports of (p=0,r=N) followed by CSI-RS ports of (p=1,r=N).

[0314] In port numbering scheme 2, the CSI-RS ports are numbered according to the order of (polarization p, NZP CSI-RS resource r) as:

[0315] -CSI-RS ports of (p=0,r=1) followed by CSI-RS ports of (p=0,r=1), …, ,followed by CSI-RS ports of (p=0,r=N), and

[0316] -then CSI-RS ports of (p=1,r=1) followed by CSI-RS ports of (p=1,r=1), …, ,followed by CSI-RS ports of (p=1,r=N).

[0317] In another embodiment, a UE is configured with a CSI report associated with (or across) N≥1 NZP CSI-RS resources (or a NZP CSI-RS, N≥1 subsets of CSI-RS antenna ports or antenna port groups within a NZP CSI-RS resourcee), the CSI report is determined based on a codebook comprising components corresponding to W1, and W2. In particular, the precoder for layer l is given by

[0318]

[0319] Here,

[0320]

[0321] -W1is a block diagonal matrix including 2 blocks, where two blocks are associated with two antenna polarizations (two halves or groups of CSI-RS antenna ports) of all NZP CSI-RS resources and each block is a ×L SD basis or port selection matrix (similar to Rel. 15 / 16 / 18 Type II or Rel-15 Type I codebook or Rel. 16 / 17 / 18 Type II port selection (PS) or CJT PS codebook),

[0322] -W2is a 2L×X coefficients matrix, where e.g., X=1 or X>1, and

[0323] -γ is a normalization factor.

[0324] In one example, N≤K and K is a number of NZP CSI-RS resources (e.g., in a CSI resource set) configured for channel measurements. In one example, K is fixed (e.g., 2 or 3 or 4 or >4) or configured (e.g., via higher layer from {2,3,4} or {1,2,3,4}), or reported by the UE (e.g., as part of UE capability). In one example, the value of N can be ≥1. In one example, the value of N can be ≥2. In one example, the value of N is configured (e.g., via higher layer). In one example, the value of N is reported by the UE (e.g., as part of the CSI report). In one example, the UE is configured with N=K (i.e., no selection of NZP CSI-RS resources) or N≤K (i.e., dynamic selection of NZP CSI-RS resources by the UE). When the UE performs dynamic selection, the selected N NZP CSI-RS resources can be reported via part 1 of the two part CSI (or UCI). The reporting can be via a bitmap indicator of size K bits.

[0325] In one example, a codebook with W1of one or more embodiments herein can be based on 5G NR Rel-15 / 19 Type-I codebook (or low-resolution codebook, 5.2.2.2.1 of [REF 8]) or its 6G counterpart, where the codebook includes W1component in one or more embodiments herein and W2component for basis vector selection and / or co-phase selection.

[0326] In one example, a codebook with W1of one or more embodiments herein can be based on 5G NR Rel-16 / 19 Type-II codebook (or high-resolution codebook, 5.2.2.2.5 of [REF 8]) or its 6G counterpart, where the codebook includes W1component in one or more embodiments herein, Wfcomponent for frequency-domain basis vector selection, and W2component for coefficient selection associated with (SD, FD) basis vector pairs.

[0327] In one example, a codebook with W1of one or more embodiments herein can be based on Rel-18 Type-II codebook (or high-resolution codebook, 5.2.2.2.8 of [REF 8]) or its 6G counterpart, where the codebook includes W1component in one or more embodiments herein, Wfcomponent for frequency-domain basis vector selection, and W2component for coefficient selection associated with (SD, FD) basis vector pairs.

[0328] In one embodiment, Type-I (low-resolution) and Type-II (high-resolution) CSI reporting can be (implicitly) configured from a same codebook via configuring the value of L. The codebook is designed based on described in one or more embodiments herein.

[0329] In one example, Type-I CSI (low-resolution CSI) reporting can be (implicitly) configured when L=1 is configured or a parameter combination including L=1.

[0330] In one example, when L=1 is configured, FD compression component (i.e., component, e.g., FD basis vector selection (i1,5, i1,6) and corresponding coefficient selection) is not applied in the codebook, i.e., .

[0331] In one example, when L=1 is configured, FD compression component (i.e., component, e.g., FD basis vector selection (i1,5, i1,6) and corresponding coefficient selection) can be turned on or turned off by using a higher-layer parameter.

[0332] In one example, when L=1 is configured, FD compression component (i.e., component, e.g., FD basis vector selection (i1,5, i1,6) and corresponding coefficient selection) is applied or always turned-on (similar to high-resolution CSI), i.e., .

[0333] In one example, Type-II (high-resolution CSI) CSI reporting can be (implicitly) configured when L>1 is configured.

[0334] In one example, when L>1 is configured (or a parameter combination corresponding to L>1), FD compression component (i.e., component, e.g., FD basis vector selection (i1,5, i1,6) and corresponding coefficient selection) can be turned on or turned off by using a higher-layer parameter.

[0335] In one example, when L>1 is configured (or a parameter combination corresponding to L>1), FD compression component (i.e., component, e.g., FD basis vector selection (i1,5, i1,6) and corresponding coefficient selection) is always turned on, i.e., .

[0336] In one embodiment, Type-I (low-resolution CSI) and Type-II (high-resolution CSI) CSI reporting can be explicitly configured from a same codebook via a higher-layer parameter, e.g., codebookType, codebookMode, etc. The codebook is designed based on described in one or more embodiments herein.

[0337] In one example, for Type-I (low-resolution CSI) CSI reporting, the candidate values of L can include 1 and other value(s) larger than 1 (e.g., 4), and one out of L basis vectors is selected.

[0338] In another example, for Type-I (low-resolution CSI) CSI reporting, L=1 is only allowed to configure.

[0339] In one example, for Type-II (high-resolution CSI) CSI reporting, the candidate values of L can include values larger than 1 (e.g., 2,4,6).

[0340] In one example, for Type-II (high-resolution CSI) CSI reporting, the candidate values of L can include 1 and other values larger than 1 (e.g., 2,4,6).

[0341] In the examples described in this disclosure, the terminology of Type-I / Type-II should not be limited to the scope of this disclosure. They can be denoted by different terminologies such as low-resolution / high-resolution CSI codebook, low-resolution / high-resolution CSI reporting, etc. for example, in 6G.

[0342] FIG. 16 illustrates an example of codebook based components used for determining a CSI report 1600 according to embodiments of the present disclosure This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0343] As shown in FIG. 16, at least one of the following examples is used / configured regarding W1and W2

[0344] In one example, W1is a block diagonal matrix comprising 2 blocks, W1,1and W1,2, are (spatial-domain, SD) basis matrices associated with two antenna polarizations (two halves or groups of CSI-RS antenna ports) of (all) N NZP CSI-RS resources or a CSI-RS, and W2can be , is a L-element column (selection) vector containing a value of 1 in element j or (j mod L) and zeros elsewhere, and c is a coefficient. Note that when L=1, , hence does not need reporting when L>1.

[0345] In one example, is a PCSIRS×2L SD basis matrix, where the L SD basis vectors comprising columns of B are determined the same way as in Rel. 15 / 16 Type II codebooks (cf. 5.2.2.2.3, REF 8), i.e., the SD basis vectors ,i=0,1,…,L-1 are indentified by the indices q1,q2,n1, n2, can be indicated by PMI components i1,1, i1,2, and are obtained as in 5.2.2.2.3 of [REF 8].

[0346]

[0347] Let

[0348]

[0349] and

[0350]

[0351] where the values of C(x,y) are given in Table 5.2.2.2.3-1 [REF8].

[0352] The quantities , are given by

[0353]

[0354] and correspond to the DFT beam (vector) indices in the oversampled DFT codebook.

[0355] FIG. 17 illustrates an example of an orthogonal basis set 1700 according to embodiments of the present disclosure. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0356] The L DFT beams or DFT vectors are selected or identified by the components i1,1and i1,2of the codebook index i1, where (q1,q2) indicates the orthogonal basis set comprising of N1N2DFT beams, an example of which is shown in FIG. 17 for (q1,q2)=(0,0) where beams are shown as black squares located in an (N1,N2) grid.

[0357] For the L out N1N2beam selection, the N1N2beams in the orthogonal basis set, indicated by (q1,q2), are sorted or numbered according to at least one of the following schemes:

[0358] Scheme 0: Starting from the leading beam (q1,q2), N1N2 beams in the orthogonal basis set are sorted or numbered sequentially 0 to N1N2-1 first in the 1st dimension and then in the 2nd dimension. For a given beam in the orthogonal basis set, the sorted beam index is then given by where the indices i=0,1,…,L-1 are assigned such that n(i)increases as i increases.

[0359] Scheme 1: Starting from the leading beam (q1,q2), N1N2beams are numbered sequentially 0 to N1N2- 1 first in the 2nd dimension and then in the 1st dimension. For a given beam in the orthogonal basis set, the sorted beam index is then given by where the indices i=0,1,…,L-1 are assigned such that n(i)increases as i increases.

[0360] FIG. 18 illustrates an example of a beam sorting (numbering) scheme 1800 according to embodiments of the present disclosure. This example is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0361] The sorted beam indices n(i)∈{0,1,...,N1N2-1}. An illustration of the two beam sorting (numbering) schemes are shown in FIG. 18. An example of L = 2 out of N1N2= 16 beam selection is also shown according to the two schemes, where for Beam 0 and , =(1,2) for Beam 1. According to Scheme 0, Beam 0 and Beam 1 are numbered as n(0)=4 and n(1)=9, respectively, and according to Scheme 1, they are numbered as n(0)=1 and n(1)=6, respectively.

[0362] For a given antenna port layout (N1,N2) and oversampling factors (O1,O2) for two dimensions, a DFT vector (the superscript N1and N2shall be used when needed in this disclosure) can be expressed as follows.

[0363]

[0364] where l∈{0,1,…,O1N1-1} and m∈{0,1,…,O2N2-1}. Here, (O1,O2) can be fixed, e.g., (1,1), (2,2), (2,1), (2,2), (4,1), or (4,4), or configured. (O1,O2) can be different across resources. (O1,O2) can depend on (N1,N2). For example, OiNi= or ≤ where can be fixed, e.g., 64, 128 or configured.

[0365] Let PCSIRS,r=2N1,rN2,rbe number of CSI-RS ports associated with CSI-RS resource r. Let K=M1M2be a total number of resources or port groups, where Miis a number of resources in i-th dimension, and i=1,2. In one example, the UE is configured with one of the following:

[0366] -In one example, the UE is configured with K or (M1,M2), and PCSIRS,r.

[0367] -In one example, the UE is configured with K or (M1,M2), and PCSIRS.

[0368] -In one example, the UE is configured with PCSIRS, and PCSIRS,r.

[0369] -In one example, the UE is configured with K or (M1,M2), PCSIRS,rand PCSIRS.

[0370] In one example, where ∈{0,1,…,NPSK-1}, and NPSK=2 (for BPSK), NPSK=4 (for QPSK), 8 (for 8PSK), or 16 (for 16PSK). In one example, NPSKis fixed, e.g., NPSK=4, or NPSK=2. In one example, NPSKis configured via higher layer, e.g., from {2,4}. In one example, UE determines / selects which NPSKis used and reports it as a part of CSI. In one example, the range of is a subset of {0,1,…,NPSK-1}. For example, . In another example, .

[0371] The selection vector and coefficient c are indentified by the indices j∈{0,1,…,L-1} and respectively, can be indicated by PMI components i2,1, i2,2, and are obtained as

[0372]

[0373] In one example, where p is an amplitude or power level. The selection vector and coefficient c for are indentified by the indices j∈{0,1,…,L-1} and respectively, can be indicated by PMI components i2,1, i2,2, i2,3, and are obtained as

[0374] .

[0375] The selection vector indicator i2,1=j.

[0376] The phase coefficient indicators i2,2= .

[0377] The amplitude coefficient indicators i2,3=k.

[0378] In one example, the mapping from k to the amplitude coefficient p is given one of the examples in Table 1.

[0379]

[0380] In one example, the rank-1 (1-layer) precoder is then given by

[0381]

[0382] In another variation (V1) of previous example, where c0and c1are coefficients (phase only or phase and amplitude) associated with two antenna polarizations (0 and 1).

[0383]

[0384] In another variation (V2) of previous example, where j0and j1are selected basis vectors associated with two antenna polarizations (0 and 1).

[0385] In another variation (V3) of previous example, where j0and j1are selected basis vectors associated with two antenna polarizations (0 and 1), and c0and c1are coefficients (phase only or phase and amplitude) associated with two antenna polarizations (0 and 1).

[0386] In general, as an example, the selection vector and coefficient cpfor p=0,1 are indentified by the indices jp∈{0,1,…,L-1} and respectively, can be indicated by PMI components i2,1, i2,2, i2,3, and are obtained as

[0387]

[0388] In general, as an example, the rank-1 (1-layer) precoder can be given by

[0389]

[0390] Where depending on the above-mentioned variations, either

[0391] -j0and j1can be the same, i.e., j0=j1, or

[0392] -j0and j1can be different, i.e., both j0=j1and j0≠j1are possible, or

[0393] -k0and k1can be the same, i.e., k0=k1, or

[0394] -k0and k1can be different, i.e., both k0=k1and k0≠k1are possible, or

[0395] -c0can be fixed (e.g., 1) and c0=c1or c0≠c1.

[0396] In one example, the W1has the following structure, i.e., SD basis vectors are the same for two polarizations (polarization common) but can be different across layers (layer-specific):

[0397]

[0398] where including L SD basis vectors (as columns), and is the number of layers (i.e., rank).

[0399] In one example (for layer-specific q1,q2), the SD basis vectors ,i=0,1,…,L-1, l=1,…, are indicated by PMI components i1,1,l, i1,2,l, where

[0400]

[0401] In another example (for layer-specific q1,q2), the SD basis vectors ,i=0,1,…,L-1, l=1,…, are indicated by PMI components i1,1, i1,2, where

[0402]

[0403] In one example (for layer-common q1,q2), the SD basis vectors ,i=0,1,…,L-1, l=1,…, are indicated by PMI components i1,1, i1,2,l, where

[0404]

[0405] In another example (for layer-common q1,q2), the SD basis vectors ,i=0,1,…,L-1, l=1,…, are indicated by PMI components i1,1, i1,2, where

[0406]

[0407] In one example, the W1has the following structure, i.e., SD basis vectors can be different across two polarizations (polarization-specific) but are the same for all layers (layer-common):

[0408]

[0409] where including L SD basis vectors (as columns), and is the number of layers (i.e., rank).

[0410] In one example (for layer-specific q1,q2), the SD basis vectors ,i=0,1,…,L-1, p=0,1 are indicated by PMI components i1,1,p, i1,2,p, where

[0411]

[0412] In another example (for layer-specific q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1, are indicated by PMI components i1,1, i1,2, where

[0413]

[0414] In one example (for layer-common q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1 are indicated by PMI components i1,1, i1,2,p, where

[0415]

[0416] In another example (for layer-common q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1 are indicated by PMI components i1,1, i1,2, where

[0417]

[0418] In one example, the W1has the following structure, i.e., SD basis vectors can be different across two polarizations (polarization-specific) and can be different across layers (layer-specific):

[0419]

[0420] where including L SD basis vectors (as columns), and is the number of layers (i.e., rank).

[0421] In one example (for layer-specific and polarization-specific q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1,l=1,2,…, are indicated by PMI components i1,1,l,p, i1,2,l,p, where

[0422]

[0423] In another example (for layer-specific and polarization-specific q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1,l=1,2,…, are indicated by PMI components i1,1, i1,2, where

[0424]

[0425] In one example (for layer-specific but polarization-common q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1,l=1,2,…, are indicated by PMI components i1,1,l, i1,2,l,p, where

[0426]

[0427] In another example (for layer-specific but polarization-common q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1,l=1,2,…, are indicated by PMI components i1,1, i1,2, where

[0428]

[0429] In one example (for polarization-specific but layer-common q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1,l=1,2,…, are indicated by PMI components i1,1,p, i1,2,l,p, where

[0430]

[0431] In another example (for polarization-specific but layer-common q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1,l=1,2,…, are indicated by PMI components i1,1, i1,2, where

[0432]

[0433] In one example (for polarization-common and layer-common q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1,l=1,2,…, are indicated by PMI components i1,1, i1,2,l,p, where

[0434]

[0435] In another example (for polarization-common and layer-common q1,q2), the SD basis vectors =0,1,…,L-1, p=0,1,l=1,2,…, are indicated by PMI components i1,1, i1,2, where

[0436]

[0437] In one example, the L SD basis vectors comprising columns of B are determined the same way as in Rel. 15 Type I codebooks (5.2.2.2.1, REF 8), i.e., the L SD basis vectors are indentified by the indices i1,1, i1,2, and are obtained as in 5.2.2.2.1 of [REF 8].

[0438] In one example, i1,1is selected from {0,1,…,N1O1-1} and i1,2is selected from {0,1,…,N2O2-1} to indicate one SD basis vector among N1N2O1O2candidate basis vectors.

[0439] In one example, i1,1,lis selected from {0,1,…,N1O1-1} and i1,2,lis selected from {0,1,…,N2O2-1} to indicate one SD basis vector among N1N2O1O2candidate basis vectors, for each layer l=1,…, .

[0440] In one example, i1,1is selected from and i1,2is selected from to indicate four SD basis vectors among N1N2O1O2candidate basis vectors.

[0441] In one example, i1,1,lis selected from and i1,2,lis selected from to indicate four SD basis vectors among N1N2O1O2candidate basis vectors, for each layer l=1,…, .

[0442] In one example, i1,1is selected from and i1,2is selected from to indicate four SD basis vectors among N1N2O1O2candidate basis vectors.

[0443] In one example, i1,1,lis selected from and i1,2,lis selected from to indicate four SD basis vectors among N1N2O1O2candidate basis vectors, for each layer l=1,…, .

[0444] In one example, i1,1is selected from and i1,2is selected from {0} to indicate four SD basis vectors (hence no report) among N1N2O1O2candidate basis vectors.

[0445] In one example, i1,1,lis selected from and i1,2,lis selected from {0} to indicate four SD basis (hence no report) vectors among N1N2O1O2candidate basis vectors, for each layer l=1,…, .

[0446] In one example, i1,1is selected from and i1,2is selected from {0,1,…,N2O2-1} to indicate four SD basis vectors among N1N2O1O2candidate basis vectors.

[0447] In one example, i1,1,lis selected from and i1,2,lis selected from {0,1,…,N2O2-1} to indicate four SD basis vectors among N1N2O1O2candidate basis vectors, for each layer l=1,…, .

[0448] In one embodiment for rank value ( ) > 1, at least one of the following example is used / configured. Let and denote that W1and W2components for υ layers.

[0449] In one example, all components of W1and W2are determined / reported according to each example described in one or more embodiments herein for layers l=1,…,υ.

[0450] -In one example, L=1, or

[0451] -In one example, L>1, or

[0452] -In one example, L∈{1,x} where x>1.

[0453] In one example, L=1 for each rank υ≥1.

[0454] In one example, L∈{1,x} for rank 1 and L=1 for each rank υ>1.

[0455] In one example, L∈{1,x} for rank 1,2 and L=1 for each rank υ>2.

[0456] In one example, L∈{1,x} for rank 1,2,3,4 and L=1 for each rank υ>4.

[0457] In one example, x=2, x=4, or x=6 in the above examples.

[0458] In one example, the rotation factor (q1,q2) are determined / reported common for all layers, and L SD basis vectors and all components of W2, as described above, are determined / reported independently for each layer l=1,…,υ, and W2is determined / reported for each layer l=1,…,υ.

[0459] In one example, all components of W1, as described above, are determined / reported common for all layers, and all components of W2, as described above, are determined / reported independently for each layer l=1,…,υ, and W2is determined / reported for each layer l=1,…,υ.

[0460] In one example, all components of W1, as described above, are determined / reported independently for each layer l=1,…,υ, and one joint W2across υ layers are determined / reported, where the columns of W2correspond to W2for υ layers.

[0461] In one example, the rotation factor (q1,q2) are determined / reported common for all layers, L SD basis vectors, as described above, are determined / reported independently for each layer l=1,…,υ, and one joint W2across υ layers are determined / reported, where the columns of W2correspond to W2for υ layers.

[0462] In one example, all components of W1, as described above, are determined / reported common for all layers, and one joint W2across υ layers are determined / reported, where the columns of W2correspond to W2for υ layers.

[0463] In one embodiment, when the number of layers (rank) υ=2, the rank-2 (2-layer) precoding matrix is given by

[0464]

[0465] At least one of the following examples is used / configured regarding U(2).

[0466] In one example, where (precoder structure A1).

[0467] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector b (as described in an example of one or more embodiments herein) and i2indicates c (in a subband (SB) manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0468] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector b out of the L SD vectors (in a SB manner).

[0469] In one example, where and cl, l=1,2 is a co-phase for layer l (precoder structure A2).

[0470] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector b (as described in an example of one or more embodiments herein) and i2indicates cl, l=1,2 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0471] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates cl, l=1,2 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector b out of the L SD vectors (in a SB manner).

[0472] In one example, where , l=1,2 is a DFT vector for layer l (precoder structure A3).

[0473] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector blfor l=1,2 (as described in an example of one or more embodiments herein) and i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0474] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector blout of the L SD vectors (in a SB manner) for each layer l=1,2.

[0475] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate two SD vectors b1and b2out of the L SD vectors (in a SB manner).

[0476] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors Blfor each layer l=1,2 (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vectors blout of the L SD vectors (in a SB manner) for each layer l=1,2.

[0477] In one example, where bland clare as described above (precoder structure A4).

[0478] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector blfor l=1,2 (as described in an example of one or more embodiments herein) and i2indicates clfor l=1,2 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0479] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector blout of the L SD vectors (in a SB manner) for each layer l=1,2.

[0480] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate two SD vectors b1and b2out of the L SD vectors (in a SB manner).

[0481] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors Blfor each layer l=1,2 (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vectors blout of the L SD vectors (in a SB manner) for each layer l=1,2.

[0482] In one example, where ∈{0,1,…,NPSK-1}, and NPSK=2 (for BPSK), NPSK=4 (for QPSK), 8 (for 8PSK), or 16 (for 16PSK). In one example, NPSKis fixed, e.g., NPSK=4, or NPSK=2. In one example, NPSKis configured via higher layer, e.g., from {2,4}. In one example, the UE determines / selects which NPSKis used and reports it as a part of CSI. In one example, the range of is a subset of {0,1,…,NPSK-1}. For example, . In another example, . In one example, , where e.g., x=2. In one example, x=4.

[0483] In one example, NPSK(or the number of cophase values) depends on rank value (i.e., RI or rank value ). In one example, NPSKcan be according to at least one of the following examples.

[0484] -In one example, NPSK=npsk,1for υ≤a and NPSK=npsk,2for υ>a.

[0485] -In one example, NPSK=npsk,1for υ<a and NPSK=npsk,2for υ≥a.

[0486] -In one example, NPSK=npsk,1for υ∈A and NPSK=npsk,2for υ∈B.

[0487] -In one example, NPSK=npsk,1for υ=1 and NPSK=npsk,2for υ>1.

[0488] -In one example, NPSK=npsk,lfor l=1,..,υ.

[0489] -In one example, a=4. In one example, a=5. In one example, a=1. In one example, a=2. In one example, a=3. In one example, a=6. In one example, a=7. In one example, a=8.

[0490] -In one example, npsk,1>npsk,2. In one example, (npsk,1,npsk,2)=(4,2).

[0491] -In one example, npsk,1<npsk,2. In one example, (npsk,1,npsk,2)=(2,4).

[0492] -In one example, npsk,1=npsk,2. In one example, (npsk,1,npsk,2)=(4,4). In one example, (npsk,1,npsk,2)=(2,2).

[0493] -In one example, A includes 1. In one example, A includes 2. In one example, A includes 1 and 2.

[0494] -In one example, B includes 3. In one example, B includes 4. In one example, B includes 3 and 4.

[0495] In one example, where plis an amplitude or power level.

[0496] In this disclosure, coefficient clcan be reported in a WB manner or in a SB manner.

[0497] In one embodiment, when the number of layers (rank) υ=3, the rank-3 (3-layer) precoding matrix is given by

[0498]

[0499] At least one of the following examples is used / configured regarding U(2).

[0500] In one example, or where (precoder structure A1).

[0501] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector b (as described in an example of one or more embodiments herein) and i2indicates c (in a subband (SB) manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0502] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector b out of the L SD vectors (in a SB manner).

[0503] In one example, where and cl, l=1,2,3 is a co-phase for layer l (precoder structure A2).

[0504] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector b (as described in an example of one or more embodiments herein) and i2indicates cl, l=1,2,3 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0505] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates cl, l=1,2,3 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector b out of the L SD vectors (in a SB manner).

[0506] In one example, or where , l=1,2,3 is a DFT vector for layer l (precoder structure A3).

[0507] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector blfor l=1,2,3 (as described in an example of one or more embodiments herein) and i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0508] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector blout of the L SD vectors (in a SB manner) for each layer l=1,2,3.

[0509] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate two SD vectors b1and b2out of the L SD vectors (in a SB manner).

[0510] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors Blfor each layer l=1,2,3 (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vectors blout of the L SD vectors (in a SB manner) for each layer l=1,2,3.

[0511] In one example, where bland clare as described above (precoder structure A4).

[0512] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector blfor l=1,2,3 (as described in an example of one or more embodiments herein) and i2indicates clfor l=1,2,3 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0513] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2,3 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector blout of the L SD vectors (in a SB manner) for each layer l=1,2,3.

[0514] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2,3 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate two SD vectors b1and b2out of the L SD vectors (in a SB manner).

[0515] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors Blfor each layer l=1,2,3 (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2,3 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vectors blout of the L SD vectors (in a SB manner) for each layer l=1,2,3.

[0516] In one embodiment, when the number of layers (rank) υ=4, the rank-4 (4-layer) precoding matrix is given by

[0517]

[0518] At least one of the following examples is used / configured regarding U(2).

[0519] In one example, or where (precoder structure A1).

[0520] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector b (as described in an example of one or more embodiments herein) and i2indicates c (in a subband (SB) manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0521] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector b out of the L SD vectors (in a SB manner).

[0522] In one example, where and cl, l=1,2,3,4 is a co-phase for layer l (precoder structure A2).

[0523] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector b (as described in an example of one or more embodiment herein) and i2indicates cl, l=1,2,3,4 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0524] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates cl, l=1,2,3,4 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector b out of the L SD vectors (in a SB manner).

[0525] In one example, or where , l=1,2,3,4 is a DFT vector for layer l (precoder structure A3).

[0526] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector blfor l=1,2,3,4 (as described in an example of one or more embodiments herein) and i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0527] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector blout of the L SD vectors (in a SB manner) for each layer l=1,2,3,4.

[0528] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate two SD vectors b1and b2out of the L SD vectors (in a SB manner).

[0529] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors Blfor each layer l=1,2,3,4 (as described in an example of one or more embodiments herein) and a first part of i2indicates c (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vectors blout of the L SD vectors (in a SB manner) for each layer l=1,2,3,4.

[0530] In one example, where bland clare as described above (precoder structure A4).

[0531] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector blfor l=1,2,3,4 (as described in an example of one or more embodiments herein) and i2indicates clfor l=1,2,3,4 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0532] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2,3,4 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector blout of the L SD vectors (in a SB manner) for each layer l=1,2,3,4.

[0533] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2,3,4 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate two SD vectors b1and b2out of the L SD vectors (in a SB manner).

[0534] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors Blfor each layer l=1,2,3,4 (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2,3,4 (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vectors blout of the L SD vectors (in a SB manner) for each layer l=1,2,3,4.

[0535] In one embodiment, when the number of layers (rank) υ>4, the rank-v (v-layer) precoding matrix is given by

[0536]

[0537] In one example, where and cl, l=1,2,3,…,υ is a co-phase for layer l (precoder structure A2).

[0538] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector b (as described in an example of one or more embodiments herein) and i2indicates cl, l=1,2,3,…,υ (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0539] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates cl, l=1,2,3,…,υ (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector b out of the L SD vectors (in a SB manner).

[0540] In one example, where bland clare as described above (precoder structure A4).

[0541] -In one example, for L=1, the indicator (i1,1,i1,2) indicates an SD vector blfor l=1,2,3,…,υ (as described in an example of one or more embodiments herein) and i2indicates clfor l=1,2,3,…,υ (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein).

[0542] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2,3,…,υ (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vector blout of the L SD vectors (in a SB manner) for each layer l=1,2,3,…υ.

[0543] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors B (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2,3,…,υ (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate two SD vectors b1and b2out of the L SD vectors (in a SB manner).

[0544] -In one example, for L>1, the indicator (i1,1,i1,2) indicates L SD vectors Blfor each layer l=1,2,3,…,υ (as described in an example of one or more embodiments herein) and a first part of i2indicates clfor l=1,2,3,…,υ (in a SB manner), using an NPSK-PSK scheme (as described in an example of one or more embodiments herein), and a second part of i2indicate an SD vectors blout of the L SD vectors (in a SB manner) for each layer l=1,2,3,…,υ.

[0545] In one embodiment, a precoding matrix for low-resolution CSI (described in an example of embodiment I) can be compressed with a FD compression component, where cophase values across N3 SBs (or FD compression units) are compressed by the FD compression component. For N3 cophase values (for each layer l=1,…,v), it is compressed via two components with M (or Mv) FD basis vector selection and M cophase value selection. In one example, the CSI report includes an indicator of M (or Mv) FD basis vector selection and M cophase value selection.

[0546] In this disclosure, we use M but it can be denoted as Mv(similar to 5G NR Rel-16 eType-II CSI).

[0547] For a given layer, for N3 cophase values, denoted as a vector wcop that includes the N3 cophase values, it can be expressed as

[0548]

[0549] where Wfis a N3×M matrix, including M FD vectors and is a M×1 coefficient vector including M coefficients. In one example, the CSI report includes an indicator(s) for selected M FD vectors and an indicator(s) for selected M coefficients.

[0550] In one example, for the M FD basis vector selection, they are selected from a set of (oversampled) DFT vectors. For a given N3and oversampling factors O3, a DFT vector yfcan be expressed as follows.

[0551]

[0552] where f∈{0,1,…,O3N3-1}. In one example, O3is fixed or configured. In one example O3=1. In one example, O3=1 or 4 and can be configured via higher-layer signaling.

[0553] In one example, for an indicator indicating the M FD basis vectors, it follows an indication way of FD basis vector selection for 5G NR Rel-16 / 19 eType-II CSI or its 6G counterpart.

[0554] In one example, for one of the M FD basis vectors, it is fixed and corresponds to y0=[1 1… 1]T. In one example, in this case, M-1 FD basis vectors are selected from a DFT vector set excluding y0. In this case, for example, f can be selected from {1,2,…,O3N3-1} for the example above for the DFT vector set.

[0555] Denote each of the M coefficients of by for i=1,…,M for a given layer.

[0556] In one example, where ∈{0,1,…,NPSK-1}, and NPSK=2 (for BPSK), NPSK=4 (for QPSK), 8 (for 8PSK), or 16 (for 16PSK). In one example, NPSKis fixed, e.g. NPSK=4, or NPSK=2. In one example, NPSKis configured via higher layer, e.g. from {2,4}. In one example, UE determines / selects which NPSKis used and reports it as a part of CSI. In one example, the range of is a subset of {0,1,…,NPSK-1}. For example, . In another example, .

[0557] In one example, 　 where ∈{0,1,…,NPSK-1}, and NPSK=2 (for BPSK), NPSK=4 (for QPSK), 8 (for 8PSK), or 16 (for 16PSK), p is an amplitude or power value. In one example, NPSKis fixed, e.g. NPSK=4, or NPSK=2. In one example, NPSKis configured via higher layer, e.g. from {2,4}. In one example, UE determines / selects which NPSKis used and reports it as a part of CSI. In one example, the range of is a subset of {0,1,…,NPSK-1}. For example, . In another example, .

[0558] In one embodiment, for a beta value 0<β≤1, for a given layer, are non-zero coefficients, and among the M coefficients, M’ coefficients are reported. For example, for each of the M’ coefficients, phase value is indicated and reported according to one of the examples for .

[0559] In one example, a M-bit bitmap (for each layer) is included in the CSI report, where each bit indicates whether the corresponding coefficient is non-zero or not.

[0560] In one embodiment, for a beta value 0<β≤1, across all layers l=1,2,..,υ, or are non-zero coefficients, and among the vM coefficients, M’ coefficients are reported. For example, for each of the M’ coefficients, phase value is indicated and reported according to one of the examples for .

[0561] In one example, a M-bit bitmap (for each layer) is included in the CSI report, where each bit indicates whether the corresponding coefficient is non-zero or not.

[0562] In one example, can be calculated / determined via an algorithm. In one example, a UE can find an optimum unquantized co-phase value for each of the N3 FD compression units, and then chooses the best M FD vectors out of the O3N3DFT vectors along with M phase selection in .

[0563] In one embodiment, CQI values can be compressed with a FD compression component, where CQI values across N3SBs (or FD compression units) are compressed by the FD compression component. For N3CQI values, it is compressed via M (or Mv) FD vector selection and M coefficient selection. In one example, the CSI report includes an indicator of M (or Mv) FD vector selection and M coefficient selection.

[0564] In this disclosure, we use M but it can be denoted as Mv(similar to 5G NR Rel-16 eType-II CSI).

[0565] For N3CQI values, denoted as a vector wCQIthat includes the N3CQI values, it can be expressed as

[0566]

[0567] where Wfis a N3×M matrix, including M FD vectors and is a M×1 coefficient vector including M coefficients, and g(·) is a function to map CQI index. In one example, the CSI report includes an indicator(s) for selected M FD vectors and an indicator(s) for selected M coefficients.

[0568] In one example, for the M FD basis vector selection, they are selected from a set of (oversampled) DFT vectors. For a given N3and oversampling factors O3, a DFT vector yfcan be expressed as follows.

[0569]

[0570] where f∈{0,1,…,O3N3-1}. In one example, O3is fixed or configured. In one example O3=1. In one example, O3=1 or 4 and can be configured via higher-layer signaling.

[0571] In one example, for an indicator indicating the M FD basis vectors, it follows an indication way of FD basis vector selection for 5G NR Rel-16 / 19 eType-II CSI or its 6G counterpart.

[0572] In one example, for one of the M FD basis vectors, it is fixed and corresponds to y0=[1 1… 1]T. In one example, in this case, M-1 FD basis vectors are selected from a DFT vector set excluding y0. In this case, for example, f can be selected from {1,2,…,O3N3-1} for the example above for the DFT vector set.

[0573] In one example, Wfis an N3×N3identity matrix, (i.e., in this case M=N3) hence no reporting quantity is included for the component Wf.

[0574] Let denote each of the M coefficients of by for i=1,…,M for a given layer.

[0575] In one example, where ∈{0,1,…,NPSK-1}, and NPSK=2 (for BPSK), NPSK=4 (for QPSK), 8 (for 8PSK), or 16 (for 16PSK), p is an amplitude or power value. In one example, NPSKis fixed, e.g. NPSK=4, or NPSK=2. In one example, NPSKis configured via higher layer, e.g. from {2,4}. In one example, UE determines / selects which NPSKis used and reports it as a part of CSI. In one example, the range of is a subset of {0,1,…,NPSK-1}. For example, . In another example, .

[0576] In one example, the value of is selected from CQI indices, i.e., {0,1,2,…,15} or {0,1,2,3,…,31}, {0,1,..,7}, or {0,1,..,3}.

[0577] In one embodiment, for a beta value 0<β≤1, are non-zero coefficients, and among the M coefficients, M’ coefficients are reported. For example, for each of the M’ coefficients, it is indicated and reported according to one of the examples for .

[0578] In one example, a M-bit (or N3-bit) bitmap (for each layer) is included in the CSI report, where each bit indicates whether the corresponding coefficient is non-zero or not.

[0579] In another embodiment, a M-bit (or N3-bit) bitmap (for each layer) is included in the CSI report, regardless of beta value, where each bit indicates whether the corresponding coefficient is non-zero or not. In one example, the M-bit (or N3-bit) bitmap is in CSI Part 1 and an indicator(s) for is in CSI Part 2.

[0580] In one embodiment, for a CSI report including CQI and PMI, a parameter combination for beta and pv(or M) is applied for both CQI and PMI selection.

[0581] In one embodiment, for a CSI report including CQI and PMI, a parameter value for beta is independently applied (can be different) for CQI and PMI selection, respectively.

[0582] In one embodiment, for a CSI report including CQI and PMI, a parameter value for pv(or M) is independently applied (can be different) for CQI and PMI selection, respectively.

[0583] In one embodiment, for a CSI report including CQI and PMI, a parameter combination for beta and pv(or M) is independently (can be different) for CQI and PMI selection, respectively.

[0584] FIG. 19 illustrates an example method 1900 performed by a UE in a wireless communication system according to embodiments of the present disclosure. The method 1900 of FIG. 19 can be performed by any of the UEs 111-116 of FIG. 1, such as the UE 116 of FIG. 3, and a corresponding method can be performed by any of the BSs 101-103 of FIG. 1, such as BS 102 of FIG. 2. The method 1900 is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0585] The method 1900 begins with the UE receiving information about a CSI report (1910). For example, in 1910, the information indicates an antenna port group. The UE then determines a SD basis vector (1920). For example, in 1920, the determination is based on the received information. The SD basis vector is denoted as bland for layers l=1,2…,υ.

[0586] The UE then determines a coefficient value (1930). For example, in 1930, the determination is based on the received information. The coefficient value is cl,nand for layer l=1,2…,υ and for SB n=0,…,N3-1, where υ is a rank value and N3is a number of SBs and where the coefficient value is represented by a FD compression component and a coefficient component.

[0587] The UE then transmits the CSI report including a PMI (1940). For example, in 1940, the PMI includes a first indicator for the SD basis vector, a second indicator for the FD compression component, and a third indicator for the coefficient component.

[0588] In various embodiments, for a given layer l, the coefficient value cl,nfor SB n=0,…,N3-1 corresponds to , where Wlis the FD compression component and a N3×M matrix, and is the coefficient component and a M×1 vector. In various embodiments, a column vector yfof Wlis a 1D discrete Fourier transform (DFT) vector, expressed as where f∈{0,1,…,N3-1}. In various embodiments, a first column of Wlis set to y0and remaining M-1 columns of Wlare specified by f∈{1,2,…,N3-1} via a combinatorial indicator with bits, and the second indicator includes the combinatorial indicator.

[0589] In various embodiments, an element of is expressed as or , where p is selected from an amplitude codebook, and is selected from a set of {0,1,…,NPSK-1}. In various embodiments, for a first element of , is set to 0, a phase of an element of remaining M-1 elements of is indicated by indicating ∈{0,1,…,NPSK-1}, via a phase indicator with bits, and the third indicator includes the phase indicator.

[0590] In various embodiments, a precoder matrix indicated by the PMI for SB n and layer l corresponds to , where PCSI-RScorresponds to a number of antenna ports associated with the antenna port group.

[0591] Any of the above variation embodiments can be utilized independently or in combination with at least one other variation embodiment. The above flowcharts illustrate example methods that can be implemented in accordance with the principles of the present disclosure and various changes could be made to the methods illustrated in the flowcharts herein. For example, while shown as a series of steps, various steps in each figure could overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps may be omitted or replaced by other steps.

[0592] Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims. None of the descriptions in this application should be read as implying that any particular element, step, or function is an essential element that must be included in the claims scope. The scope of patented subject matter is defined by the claims.

[0593] FIG. 20 is a block diagram of a terminal or user equipment (UE) 2000 according to an embodiment of the disclosure. FIG. 20 corresponds to the example of the terminal or UE of FIG. 3.

[0594] The terminal is an electronic device capable of wireless communication and having various form factors, examples of the terminal may include a UE, a mobile station (MS), a cellular phone, a smartphone, a computer, a tablet, a wearable device, an Internet of Things (IoT) device, or any other device / system capable of performing wireless communication with a base station (BS) and / or another terminal through a wireless channel.

[0595] Referring to FIG. 20, the UE 2000 may include at least one transceiver (hereinafter, referred to as simply "transceiver") 2001, at least one processor (hereinafter, referred to as simply "processor") 2002, and at least one memory (hereinafter, referred to as simply "memory") 2003. According to at least one or a combination of methods corresponding to the embodiments described in the present disclosure, the transceiver 2001, the processor 2002, and the memory 2003 of the UE 2000 may operate. However, components of the UE 2000 are not limited to the example components illustrated in FIG. 20. In another embodiment, the UE 2000 may further include additional components in addition to the above-mentioned components, or some components may be omitted. Further, in some embodiments, any combination of the transceiver 2001, the processor 2002, or the memory 2003 may be integrated in the form of one component.

[0596] The transceiver 2001 may be a communication circuit or communication circuitry that enables the UE 2000 to perform wireless communication with a node or an entity of a network. For example, the transceiver 2001 may enable the UE 2000 to transmit or receive a signal to or from a BS through cellular communication, or to transmit or receive a signal to or from another UE through cellular communication. For example, the transceiver 2001 may support at least one of various cellular communication technologies including 3rd generation (3G), 4th generation (4G), long term evolution (LTE), 5th generation (5G) NR, 6th generation (6G), and various cellular wireless communication technologies supported by the transceiver (2001) may include all subsequent generations of evolved wireless communications.

[0597] According to an embodiment, the UE 2000 may include a plurality of transceivers. For example, in the case of supporting evolved-universal terrestrial radio access-new radio (E-UTRA-NR) dual connectivity (EN-DC), the UE 2000 may include a first transceiver supporting the 4G LTE wireless communication and a second transceiver supporting the 5G NR wireless communication. According to another embodiment, in the case of supporting NR-dual connectivity (NR-DC), the UE 2000 may include a plurality of transceivers supporting the 5G NR wireless communication. According to still another embodiment, in the case of supporting near field wireless communication, the UE 2000 may separately include a transceiver supporting at least one standard in the group of wireless communication protocol standards as defined in the protocol standards for Bluetooth®, wireless local area network (WLAN) network (including institute of electrical and electronics engineers (IEEE) 802.11-2016 standard or its amendments, e.g., 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be, without being limited thereto).

[0598] According to an embodiment, the transceiver 2001 may include various circuit structures used to transmit or receive signals to or from a BS through a wireless channel. The signals may include control information and data. For example, the transceiver 2001 may include a radio frequency (RF) transmitter for up-converting and amplifying the frequency of a transmitted signal and an RF receiver for low-noise-amplifying a received signal and down-converting the frequency thereof. The transceiver 2001 may output a signal received through a wireless channel to the processor 2002 and may transmit, through a wireless channel, a signal output from the processor 2002.

[0599] The processor 2002 may control general operations of the UE 2000 according to embodiments of the disclosure. The processor 2002 may be implemented by one or more integrated circuit (or circuitry) (IC) chips and may execute various data processing operations. The processor 2002 may include at least one electric circuit, and may execute instructions (or a program, codes, data, etc.) stored in the memory 2003, individually, collectively or in any combination thereof. Further, the processor 2002 may include a single-core processor or multi-core processor, and may include a processor assembly including a plurality of processing circuits (circuitry) according to a specific implementation scheme.

[0600] The processor 2002 may be electrically, operatively, and / or communicatively coupled to the transceiver 2001 to control the transceiver 2001.

[0601] The processor 2002 may include at least one processor (or processing circuitry), and the at least one processor may perform the following operations individually, collectively or in any combination thereof. For example, the processor 2002 may include a communication processor (CP) configured to control communication operations and an application processor (AP) configured to control execution of an upper layer (for example, an application layer). In a specific embodiment, at least a part of the processor 2002 may be included in one chip (or IC) and the other part of the processor 2002 may be included in another chip (or IC). Otherwise, at least one processor may be included in another component, for example, the transceiver 2001 or the memory 2003.

[0602] The processor 2002 may perform or control or cause an operation of the UE 2000 for executing at least one or a combination of methods according to embodiments of the disclosure. For example, the processor 2002 may control operations of the UE 2000 for processing a downlink signal received from a BS or generating and transmitting an uplink signal to a BS. To this end, the processor 2002 may execute a computer program, codes, or instructions stored in the memory 2003, so as to control other components of the UE 2000 to enable execution of various operations.

[0603] The memory 2003 corresponds to a hardware storage device capable of temporarily or permanently storing information and may include one or more storage media. For example, the memory 2003 may include a memory assembly including one or more storage media. For example, the one or more storage media may include permanent memory, such as a hard drive, flash memory, or read-only memory (ROM), semipermanent memory, such as random access memory (RAM), cache memory, or a combination thereof.

[0604] The memory 2003 may be electrically, operatively, and / or communicatively coupled to the processor 2002 and may be accessed by the processor 2002.

[0605] The memory 2003 may store a computer program, codes, or instructions executable by the processor 2002. According to an embodiment, a computer program, codes, or instructions executable by the processor 2002 may be either stored in a single memory device or separated and distributedly stored in two or more memory devices. By executing the instructions stored in the memory 2003, the processor 2002 may perform various functions according to an embodiment of the disclosure.

[0606] According to an embodiment of the disclosure, operations of the UE 2000 may be caused to be performed based on execution of instructions (or a computer program or codes) stored in the memory 2003 by at least one processor (or processing circuitry) configured to execute the same individually, collectively, or in any combination thereof, based on processing circuitry that is not configured to execute instructions, and / or based on components of processing circuitry that is not configured to execute instructions.

[0607] FIG. 21 is a block diagram of a base station (BS) 2100 according to an embodiment of the disclosure. FIG. 21 corresponds to the example of the RAN node of FIG. 2.

[0608] The BS 2100 may perform wireless communication with at least one user equipment (UE) located within the area of the BS 2100 through a wireless channel. The BS 2100 may perform communication with a node or an entity of a network through wired or wireless communication.

[0609] Referring to FIG. 21, the BS 2100 may include at least one transceiver (hereinafter, referred to as simply "transceiver") 2101, at least one processor (hereinafter, referred to as simply "processor") 2102, and at least one memory (hereinafter, referred to as simply "memory") 2103. According to at least one or a combination of methods corresponding to the embodiments described in the present disclosure, the transceiver 2101, the processor 2102, and the memory 2103 of the BS 2100 may operate. However, components of the BS 2100 are not limited to the example components illustrated in FIG. 21. In another embodiment, the BS 2100 may further include additional components in addition to the above-mentioned components, or some components may be omitted. Further, in some embodiments, any combination of the transceiver 2101, the processor 2102, or the memory 2103 may be integrated in the form of one component.

[0610] The transceiver 2101 may be a communication circuit or communication circuitry that enables the BS 2100 to perform wireless communication with a node or an entity of a network. For example, the transceiver 2101 may enable the BS 2100 to transmit or receive a signal to or from the UE X00 through cellular communication, or to transmit or receive a signal to or from another network entity through wireless communication. For example, the transceiver 2101 may support various cellular communication technologies including 3rd generation (3G), 4th generation (4G), long term evolution (LTE), 5th generation (5G) NR, 6th generation (6G), and various cellular wireless communication technologies supported by the transceiver (2101) may include all subsequent generations of evolved wireless communications.. According to an embodiment, the transceiver 2101 may include various circuit structures used to transmit or receive signals to or from a UE through a wireless channel. The signals may include control information and data. For example, the transceiver 2101 may include a radio frequency (RF) transmitter for up-converting and amplifying the frequency of a transmitted signal and an RF receiver for low-noise-amplifying a received signal and down-converting the frequency thereof. The transceiver 2101 may output a signal received through a wireless channel to the processor 2102 and may transmit, through a wireless channel, a signal output from the processor 2102.

[0611] Meanwhile, according to an embodiment of the present disclosure, the BS 2100 may perform communication with a node or an entity of a network through wired or wireless communication. For example, the BS 2100 may perform wired or wireless communication with an adjacent BS, or a node or an entity of a core network through a backhaul network. Although not illustrated in FIG. 21, when the BS 2100 performs wired communication, the BS 2100 may further include a separate network interface for wired communication in addition to the transceiver 2101. The network interface may be referred to as network interface circuitry or communication interface circuitry.

[0612] The processor 2102 may control general operations of the BS 2100 according to embodiments of the disclosure. The processor 2102 may be implemented by one or more integrated circuit (or circuitry) (IC) chips and may execute various data processing operations. The processor 2102 may include at least one electric circuit, and may execute instructions (or a program, codes, data, etc.) stored in the memory 2103, individually, collectively or in any combination thereof. Further, the processor 2102 may include a single-core processor or multi-core processor, and may include a processor assembly including a plurality of processing circuits (circuitry) according to a specific implementation scheme.

[0613] The processor 2102 may be electrically, operatively, and / or communicatively coupled to the transceiver 2101 to control the transceiver 2101.

[0614] The processor 2102 may include at least one processor (or processing circuitry), and the at least one processor may perform the following operations individually, collectively or in any combination thereof. In a specific embodiment, at least a part of the processor 2102 may be included in one chip (or IC) and the other part of the processor 2102 may be included in another chip (or IC). Otherwise, at least one processor may be included in another component, for example, the transceiver 2101 or the memory 2103.

[0615] The processor 2102 may perform or control or cause an operation of the BS 2100 for executing at least one or a combination of methods according to embodiments of the disclosure. For example, the processor 2102 may control operations of the BS 2100 for generating and transmitting a downlink signal to a UE or processing an uplink signal received from a UE. Otherwise, the BS 2100 may transmit or receive a signal to or from a neighboring BS, transfer a signal received from a UE to an upper node of the network, or transmit a signal transferred from an upper node of the network to a UE. To this end, the processor 2102 may execute a computer program, codes, or instructions stored in the memory 2103, so as to control other components of the BS 2100 to enable execution of various operations.

[0616] The memory 2103 corresponds to a hardware storage device capable of temporarily or permanently storing information and may include one or more storage media. For example, the memory 2103 may include a memory assembly including one or more storage media. For example, the one or more storage media may include permanent memory, such as a hard drive, flash memory, or read-only memory (ROM), semipermanent memory, such as random access memory (RAM), cache memory, or a combination thereof.

[0617] The memory 2103 may be electrically, operatively, and / or communicatively coupled to the processor 2102 and may be accessed by the processor 2102.

[0618] The memory 2103 may store a computer program, codes, or instructions executable by the processor 2102. According to an embodiment, a computer program, codes, or instructions executable by the processor 2102 may be either stored in a single memory device or separated and distributedly stored in two or more memory devices. By executing the instructions stored in the memory 2103, the processor 2102 may perform various functions according to an embodiment of the disclosure.

[0619] According to an embodiment of the disclosure, operations of the BS 2100 may be caused to be performed based on execution of instructions (or a computer program or codes) stored in the memory 2103 by at least one processor (or processing circuitry) configured to execute the same individually, collectively, or in any combination thereof, based on processing circuitry that is not configured to execute instructions, and / or based on components of processing circuitry that is not configured to execute instructions.

[0620] The UE or the base station may perform various communication procedures related to the control plane or the user plane by cooperating with one or more network entities based on wireless communication. For example, the UE may communicate with a network entity (for example, an Access and Mobility Management Function (AMF), a Session Management Function (SMF), rtc.) via the base station, or the base station may perform at least one communication procedure by directly transmitting and receiving signals to / from, or relaying signals between, the network entities.

[0621] The structure of the above-described network entity will be described in more detail with reference to the drawings.

[0622] FIG. 22 is a block diagram of a network entity 2200 according to an embodiment of the disclosure.

[0623] The network entity 2200 may include an entity (apparatus, device, or server, etc.) that performs one or more network functions (NFs) or a part of a network function constituting a core network (e.g., a 5th generation (5G) core (5GC)) in a communication system. In this case, multiple NFs may be implemented within a single network entity, or a single NF may be distributed and implemented across a plurality of network entities. In addition, when an NF is implemented within the network entity, the NF may be implemented in the form of software, and in such a case, a program for operating the NF may be stored in memory of the network entity 2200.

[0624] A single NF may be implemented by one or more instances, which may be deployed on the same network entity or distributed across multiple network entities to operate. The instance may be a software unit that logically executes a specific network function, and may be implemented in a form that is decoupled from physical hardware resources. Further, one or more NFs may be implemented in the form of one network slice to operate to satisfy specifications required by a particular service.

[0625] The NF may include at least one of an access and mobility management function (AMF), a session management function (SMF), a local session management function (L-SMF), a user plane function (UPF), a local user plane function (L-UPF), a policy control function (PCF), a unified data management (UDM), a unified data repository (UDR), a network exposure function (NEF), a network repository function (NRF), an application function (AF), a network slice selection function (NSSF), a network data analytics function (NWDAF), a network slice admission control function (NSACF), an authentication server function (AUSF), or a data network (DN), etc.

[0626] Referring to FIG. 22, the network entity 2200 may include at least one network interface 2201, at least one processor 2202 (hereinafter, "processor"), and at least one memory 2203 (hereinafter, "memory"). As described above, a NF may be implemented in the form of a physical device such as the network entity 2200, or may be virtualized and executed in the form of an instance. When implemented as an instance, the NF need not necessarily include physical components as illustrated in FIG. 22. In such a case, the instance may be logically represented as comprising one or more logical functional elements.

[0627] According to at least one or a combination of methods corresponding to the embodiments described in the present disclosure, the network interface 2201, the processor 2202, and the memory 2203 of the network entity 2200 may operate. However, components of the network entity 2200 are not limited to the example components illustrated in FIG. 22. In another embodiment, the network entity 2200 may further include additional components in addition to the above-mentioned components, or some components may be omitted. Further, in an embodiment, the network interface 2201, the processor 2202, or the memory 2203 may be integrated in the form of one component.

[0628] The network interface 2201 is a collective term for a transmitter part of the network entity 2200 and a receiver part of the network entity 2200, and may be a communication circuit for transmitting or receiving a signal to or from a user equipment (UE), a base station (BS), or another network entity. Here, the communication circuit may include both a communication circuit for wireless communication and a communication circuit for a wired communication. For example, the network interface 2201 may include a circuit, logic, hardware, etc., configured to exchange a control plane message or a user plane message with a UE, a BS, or other core network entities through wireless communication or wired communication. The network interface 2201 may operate using various protocols (e.g., non-access stratum (NAS) protocol). The network interface 2201 may also be referred to, for convenience of description or depending on implementation, as communication circuitry, network interface circuitry, or a communication interface circuitry.

[0629] The processor 2202 may control general operations of the network entity 2200 according to embodiments of the disclosure. The processor 2202 may be implemented by one or more integrated circuit (or circuitry) (IC) chips and may execute various data processing operations. The processor 2202 may include at least one electric circuit, and may execute instructions (or a program, codes, data, etc.) stored in the memory 2203, individually, collectively or in any combination thereof. Further, the processor 2202 may include a single-core processor or multi-core processor, and may include a processor assembly including a plurality of processing circuits (circuitry) according to a specific implementation scheme. Further, it should be noted that, according to another embodiment, in a case where NF is implemented in the form of an instance, the network function may be not necessarily configured by physical hardware.

[0630] According to an embodiment, the processor 2202 may be electrically, operatively, and / or communicatively coupled to the network interface 2201 to control the network interface 2201.

[0631] The processor 2202 may include at least one processor (or processing circuitry), and the at least one processor may perform the following operations individually, collectively or in any combination thereof. In a specific embodiment, at least a part of the processor 2202 may be included in one chip (or IC) and the other part of the processor 2202 may be included in another chip (or IC). Otherwise, at least one processor may be included in another component, for example, the network interface 2201 or the memory 2203.

[0632] The processor 2202 may perform or control or cause an operation of the network entity 2200 for executing at least one or a combination of methods according to embodiments of the disclosure. For example, the processor 2202 may control operations of the network entity 2200 for exchanging a control plane message or a user plane message with a UE, a BS, or other core network entities through wireless or wired communication, using various protocols (e.g., NAS protocol). To this end, the processor 2202 may execute a computer program, codes, or instructions stored in the memory 2203, so as to control other components of the network entity 2200 to enable execution of various operations.

[0633] The memory 2203 corresponds to a hardware storage device capable of temporarily or permanently storing information and may include one or more storage media. For example, the memory 2203 may include a memory assembly including one or more storage media. For example, the one or more storage media may include permanent memory, such as a hard drive, flash memory, or read-only memory (ROM), semipermanent memory, such as random access memory (RAM), cache memory, or a combination thereof.

[0634] The memory 2203 may be electrically, operatively, and / or communicatively coupled to the processor 2202 and may be accessed by the processor 2202.

[0635] The memory 2203 may store a computer program, codes, or instructions executable by the processor 2202. According to an embodiment, a computer program, codes, or instructions executable by the processor 2202 may be either stored in a single memory device or separated and distributedly stored in two or more memory devices. By executing the instructions stored in the memory 2203, the processor 2202 may perform various functions according to an embodiment of the disclosure.

[0636] According to an embodiment of the disclosure, operations of the network entity 2200 may be caused to be performed based on execution of instructions (or a computer program or codes) stored in the memory 2203 by at least one processor (or processing circuitry) configured to execute the same individually, collectively, or in any combination thereof, based on processing circuitry that is not configured to execute instructions, and / or based on components of processing circuitry that is not configured to execute instructions.

[0637] In one embodiment, a user equipment (UE) is provided. The UE comprises a transceiver configured to receive information about a channel state information (CSI) report, the information indicating an antenna port group; and a processor operably coupled to the transceiver, the processor configured to: determine, based on the information, a spatial domain (SD) basis vector blfor layer l=1,2…,υ; and determine, based on the information, a coefficient value cl,nfor layer l=1,2…,υ and for subband (SB) n=0,…,N3-1, where v is a rank value and N3is a number of SBs, wherein the coefficient value is represented by a frequency domain (FD) compression component and a coefficient component, wherein the transceiver is further configured to transmit the CSI report including a precoding matrix indicator (PMI), and wherein the PMI includes a first indicator for the SD basis vector, a second indicator for the FD compression component, and a third indicator for the coefficient component.

[0638] In another embodiment, wherein, for a given layer l, the coefficient value cl,nfor SB n=0,…,N3-1 corresponds to:

[0639]

[0640] where: Wlis the FD compression component and a N3×M matrix, and is the coefficient component and a M×1 vector.

[0641] In another embodiment, wherein, a column vector yfof Wlis a 1D discrete Fourier transform (DFT) vector, expressed as:

[0642]

[0643] where f∈{0,1,…,N3-1}.

[0644] In another embodiment, wherein: a first column of Wlis set to y0and remaining M-1 columns of Wlare specified by f∈{1,2,…,N3-1} via a combinatorial indicator with bits, and the second indicator includes the combinatorial indicator.

[0645] In another embodiment, wherein an element of is expressed as or , where p is selected from an amplitude codebook, and is selected from a set of {0,1,…,NPSK-1}.

[0646] In another embodiment, wherein: for a first element of , is set to 0, a phase of an element of remaining M-1 elements of is indicated by indicating ∈{0,1,…,NPSK-1}, via a phase indicator with bits, and the third indicator includes the phase indicator.

[0647] In another embodiment, wherein a precoder matrix indicated by the PMI for SB n and layer l corresponds to , where PCSI-RScorresponds to a number of antenna ports associated with the antenna port group.

[0648] In one embodiment, a base station (BS) is proviede. The BS comprises a processor; and a transceiver operably coupled to the processor, the transceiver configured to: transmit information about a channel state information (CSI) report, the information indicating an antenna port group; and receive the CSI report including a precoding matrix indicator (PMI), wherein the PMI includes a first indicator for a spatial domain (SD) basis vector blfor layer l=1,2…, , a second indicator for a frequency domain (FD) compression component, and a third indicator for a coefficient component, and wherein the FD compression component and the coefficient component represent a coefficient value cl,nfor layer l=1,2…, and for subband (SB) n=0,…,N3-1, where is a rank value and N3is a number of SBs.

[0649] In another embodiment, wherein, for a given layer l, the coefficient value cl,nfor SB n=0,…,N3-1 corresponds to:

[0650]

[0651] where: Wlis the FD compression component and a N3×M matrix, and is the coefficient component and a M×1 vector.

[0652] In another embodiment, wherein, a column vector yfof Wlis a 1D discrete Fourier transform (DFT) vector, expressed as:

[0653]

[0654] where f∈{0,1,…,N3-1}.

[0655] In another embodiment, wherein: a first column of Wlis set to y0and remaining M-1 columns of Wlare specified by f∈{1,2,…,N3-1} via a combinatorial indicator with bits, and the second indicator includes the combinatorial indicator.

[0656] In another embodiment, wherein an element of is expressed as or , where p is selected from an amplitude codebook, and is selected from a set of {0,1,…,NPSK-1}.

[0657] In another embodiment, wherein: for a first element of , is set to 0, a phase of an element of remaining M-1 elements of is indicated by indicating ∈{0,1,…,NPSK-1}, via a phase indicator with bits, and the third indicator includes the phase indicator.

[0658] In another embodiment, wherein a precoder matrix indicated by the PMI for SB n and layer l corresponds to , where PCSI-RScorresponds to a number of antenna ports associated with the antenna port group.

[0659] In one embodiment, a method performed by a user equipment (UE) is provided. The method comprises receiving information about a channel state information (CSI) report, the information indicating an antenna port group; determining, based on the information, a spatial domain (SD) basis vector blfor layer l=1,2…, ; determining, based on the information, a coefficient value cl,nfor layer l=1,2…, and for subband (SB) n=0,…,N3-1, where is a rank value and N3is a number of SBs, wherein the coefficient value is represented by a frequency domain (FD) compression component and a coefficient component; and transmitting the CSI report including a precoding matrix indicator (PMI), wherein the PMI includes a first indicator for the SD basis vector, a second indicator for the FD compression component, and a third indicator for the coefficient component.

[0660] In another embodiment, wherein, for a given layer l, the coefficient value cl,nfor SB n=0,…,N3-1 corresponds to:

[0661]

[0662] where: Wlis the FD compression component and a N3×M matrix, and is the coefficient component and a M×1 vector.

[0663] In another embodiment, wherein, a column vector yfof Wlis a 1D discrete Fourier transform (DFT) vector, expressed as:

[0664]

[0665] where f∈{0,1,…,N3-1}.

[0666] In another embodiment, wherein: a first column of Wlis set to y0and remaining M-1 columns of Wlare specified by f∈{1,2,…,N3-1} via a combinatorial indicator with bits, and the second indicator includes the combinatorial indicator.

[0667] In another embodiment, wherein an element of is expressed as , where p is selected from an amplitude codebook, and is selected from a set of {0,1,…,NPSK-1}.

[0668] In another embodiment, wherein: for a first element of , is set to 0, a phase of an element of remaining M-1 elements of is indicated by indicating ∈{0,1,…,NPSK-1}, via a phase indicator with bits, and the third indicator includes the phase indicator.

[0669] Meanwhile, although specific embodiments of the present disclosure have been described in detail, various modifications may be made without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims and equivalents thereof.

Claims

1.A user equipment (UE) comprising:at least one transceiver;at least one processor communicatively coupled to the at least one transceiver; andat least one memory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the UE to:receive information about a channel state information (CSI) report, the information indicating an antenna port group;determine, based on the information, a spatial domain (SD) basis vector blfor layer l=1,2…,;determine, based on the information, a coefficient value cl,nfor layer l=1,2…,and for subband (SB) n=0,…,N3-1, whereis a rank value and N3is a number of SBs,wherein the coefficient value is represented by a frequency domain (FD) compression component and a coefficient component,transmit the CSI report including a precoding matrix indicator (PMI), andwherein the PMI includes a first indicator for the SD basis vector, a second indicator for the FD compression component, and a third indicator for the coefficient component.2.The UE of claim 1, wherein, for a given layer l, the coefficient value cl,nfor SB n=0,…,N3-1 corresponds to:where:Wlis the FD compression component and a N3×M matrix, andis the coefficient component and a M×1 vector.3.The UE of claim 2, wherein, a column vector yfof Wlis a 1D discrete Fourier transform (DFT) vector, expressed as:where f∈{0,1,…,N3-1}.4.The UE of claim 3, wherein:a first column of Wlis set to y0and remaining M-1 columns of Wlare specified by f∈{1,2,…,N3-1} via a combinatorial indicator withbits, andthe second indicator includes the combinatorial indicator.5.The UE of claim 2, wherein an element of is expressed as , where p is selected from an amplitude codebook, and is selected from a set of {0,1,…,NPSK-1}.6.The UE of claim 5, wherein:for a first element of,is set to 0,a phase of an element of remaining M-1 elements ofis indicated by indicating∈{0,1,…,NPSK-1}, via a phase indicator withbits, andthe third indicator includes the phase indicator.7.The UE of claim 1, wherein a precoder matrix indicated by the PMI for SB n and layer l corresponds to , where PCSI-RScorresponds to a number of antenna ports associated with the antenna port group.8.A base station (BS) comprising:at least one transceiver;at least one processor communicatively coupled to the at least one transceiver; andat least one memory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the base station to transmit information about a channel state information (CSI) report, the information indicating an antenna port group; andreceive the CSI report including a precoding matrix indicator (PMI),wherein the PMI includes a first indicator for a spatial domain (SD) basis vector blfor layer l=1,2…,, a second indicator for a frequency domain (FD) compression component, and a third indicator for a coefficient component, andwherein the FD compression component and the coefficient component represent a coefficient value cl,nfor layer l=1,2…,and for subband (SB) n=0,…,N3-1, whereis a rank value and N3is a number of SBs.9.The BS of claim 8, wherein, for a given layer l, the coefficient value cl,nfor SB n=0,…,N3-1 corresponds to:where:Wlis the FD compression component and a N3×M matrix, andis the coefficient component and a M×1 vector.10.The BS of claim 9, wherein, a column vector yfof Wlis a 1D discrete Fourier transform (DFT) vector, expressed as:where f∈{0,1,…,N3-1}.11.The BS of claim 10, wherein:a first column of Wlis set to y0and remaining M-1 columns of Wlare specified by f∈{1,2,…,N3-1} via a combinatorial indicator withbits, andthe second indicator includes the combinatorial indicator.12.The BS of claim 9, wherein an element of is expressed as , where p is selected from an amplitude codebook, and is selected from a set of {0,1,…,NPSK-1}.13.The BS of claim 12, wherein:for a first element of,is set to 0,a phase of an element of remaining M-1 elements ofis indicated by indicating∈{0,1,…,NPSK-1}, via a phase indicator withbits, andthe third indicator includes the phase indicator.14.The BS of claim 8, wherein a precoder matrix indicated by the PMI for SB n and layer l corresponds to , where PCSI-RScorresponds to a number of antenna ports associated with the antenna port group.15.A method performed by a user equipment (UE), the method comprising:receiving information about a channel state information (CSI) report, the information indicating an antenna port group;determining, based on the information, a spatial domain (SD) basis vector blfor layer l=1,2…,;determining, based on the information, a coefficient value cl,nfor layer l=1,2…,and for subband (SB) n=0,…,N3-1, whereis a rank value and N3is a number of SBs, wherein the coefficient value is represented by a frequency domain (FD) compression component and a coefficient component; andtransmitting the CSI report including a precoding matrix indicator (PMI), wherein the PMI includes a first indicator for the SD basis vector, a second indicator for the FD compression component, and a third indicator for the coefficient component.

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