Method of enhanced reporting of channel properties for x-MIMO systems, user equipment and base station implementing said method

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present invention relates to the field of communications and, more particularly, to enhanced channel property reporting for communication systems that employ massive MIMO or extremely massive MIMO (X-MIMO) technology, as well as to devices implementing the method. A technical result of the present invention consists in an improved performance of the communication system relative to the performance of the communication system in which the selection of communication system configuration parameters is based exclusively on a metric of the correlation properties of the channel in the time domain.

Description

METHOD OF ENHANCED REPORTING OF CHANNEL PROPERTIES FOR X-MIMO SYSTEMS, USER EQUIPMENT AND BASE STATION IMPLEMENTING SAID METHOD

[0001] The present invention relates to the field of communications and, more particularly, to enhanced reporting of channel properties for communication systems that employ massive MIMO or extremely massive MIMO (X-MIMO) technology, as well as to devices implementing said method.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] The existing 5G NR communication system supports many different modes and parameters. The 6G system is expected to be implemented similarly to 5G NR in many respects, so the 6G system will also support many different modes and parameters. In particular, 6G will likely support single-user MIMO (SU-MIMO) and multi-user MIMO (MU-MIMO), and the base station (BS) must be able to decide whether the BS should transmit data in SU-MIMO mode or MU-MIMO mode.

[0009] Other parameters that the BS shall be able to choose and determine depending on current conditions include, but are not limited to: a type of codebook for obtaining channel state information (CSI); how the BS should obtain the CSI (using a codebook, or based on the reciprocity principle of the uplink (UL) and downlink (DL) channels from the sounding reference signals (SRSs) measurements); codebook parameters; how the UE should report the CSI (with one CSI value for the entire operating frequency band, or with multiple CSI values, each corresponding to respective individual subband of the operating frequency band); a periodicity of transmission of reference signals (CSI-RS, SRS) to or from a specific UE, as well as a periodicity of reporting CSI by the UE, etc.

[0010] Thus, for the 6G communication system to operate efficiently, the optimal choice of parameters, some of which are listed above, and their values shall be carried out at the BS taking into account the properties of the channel between the BS and the UE. In the 5G NR-related prior art, time domain channel properties (TDCPs) are used for these purposes, which essentially represent a metric describing the correlation properties of the communication channel only in the time domain, i.e. characterizing how quickly the channel changes. In other words, this TDCP metric is directly related to the mobility of the user, i.e. how fast the UE moves and how quickly the channel changes over time. The illustration of how the TDCP metric can be calculated according to 5G NR on CSI-RS resources in which a single-port tracking reference signal (TRS) is transmitted is given in Fig. 7.

[0011] However, according to the opinion of the present invention authors', knowledge of only the TDCP metric is not sufficient to ensure the most informed optimal choice and determination of values of the above-listed and other configuration parameters. Choosing configuration parameters based solely on the TDCP metric is not always optimal and may, at least in some cases, result in degraded communication system performance. Thus, it would be useful to completely solve the stated problem in prior art or at least mitigate it or limit its negative effect on the performance of the entire communication system. In addition, the proposed invention makes it possible to completely eliminate or at least minimize the choice of incorrect values of configuration parameters, as well as to reduce the signaling overhead required to reconfigure UEs to new parameters.

[0012] The main object of the present invention is to provide a method and an apparatus for enhanced reporting of channel properties for communication systems that employ massive MIMO or extremely massive MIMO (X-MIMO) technology.

[0013] Provided in the first aspect of the present invention is the method implemented by BS for controlling communication with UE, in which properties of the communication channel between the BS and the UE are taken into account. Said method comprises the steps of: transmitting one or more reference signals, wherein the reference signal is the CSI-RS; receiving from the UE in CSI report at least one spatial domain channel property (SDCP) value and / or at least one frequency domain channel property (FDCP) value, wherein the SDCP value represents spatial domain channel correlation corresponding to at least some CSI-RS antenna ports, and the FDCP value represents frequency domain channel correlation corresponding to at least some subcarriers of the CSI-RS antenna port; determining one or more values of one or more configuration parameters among signaling configuration parameters and CSI calculation configuration parameters based on the at least one SDCP value and / or the at least one FDCP value received from the UE; and transmitting to the UE at least one value from the determined one or more values, respectively, of the one or more configuration parameters.

[0014] In one implementation said method further comprises the step of applying at least one value of the one or more values of the one or more signaling configuration parameters to configure the downlink.

[0015] In yet another implementation of said method, said at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, carry the CSI-RS or a tracking reference signal (TRS); and said at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, are located in one or more physical resource blocks (PRBs) located in one or more adjacent time resources, for example, but not limited to, in the same orthogonal frequency division multiplexing (OFDM) slot.

[0016] In another implementation, said method further comprises the steps of: receiving at least one TDCP value, wherein the TDCP value represents a time domain channel correlation corresponding to OFDM symbols in one or more OFDM slots; wherein the determination of the one or more values of the one or more configuration parameters is carried out further based on said at least one TDCP value.

[0017] In yet another implementation of said method, one or more of a number, a periodicity of transmission and a type of said one or more CSI-RS, and values of what channel property(properties) from among SDCP, FDCP, TDCP are to be calculated at the UE and reported to the BS in the CSI report, are configured in advance for or signaled to the UE using the radio resource control (RRC) protocol, downlink control information (DCI) or the medium access control (MAC) layer.

[0018] In yet another implementation of said method one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is(are) quantized in amplitude and / or quantized in phase; wherein the method further comprises the step of configuring in advance for or signaling, using the RRC, DCI or MAC layer, to the UE that: - the calculation of one or more of said at least one SDCP value, said at least one FDCP value, said at least one TDCP value should be performed with amplitude quantization, or - the calculation of one or more of said at least one SDCP value, said at least one FDCP value, said at least one TDCP value should be performed with amplitude and phase quantization.

[0019] In yet another implementation of said method spacings of said at least some CSI-RS antenna ports over a first dimension and / or a second dimension for calculating the corresponding spatial domain channel correlation values are configured in advance for or signaled, using the RRC protocol or the MAC layer, to the UE.

[0020] In yet another implementation of said method spacing of said at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, over a single PRB or several PRBs is configured in advance for or signaled, using the RRC protocol or the MAC layer, to the UE.

[0021] In yet another implementation of said method the phase of the correlation coefficient is uniformly quantized using phase shift keying (PSK) constellation, and the amplitude of the correlation coefficient is uniformly quantized in logarithmic scale domain.

[0022] In yet another implementation of said method one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value are received from the UE in a first part of the CSI report, which has a fixed payload size; and / or one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value are received from the UE in a second part of the CSI report, which has a variable payload size.

[0023] In yet another implementation, said method further comprises one or more steps of: the amplitude of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is received from the UE in the first part of the CSI report, which has the fixed payload size; the phase of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is received from the UE in the first part of the CSI report, which has the fixed payload size; the amplitude and phase of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value are received from the UE in the first part of the CSI report, which has the fixed payload size; the amplitude of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is received from the UE in the second part of the CSI report, which has the variable payload size; the phase of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is received from the UE in the second part of the CSI report, which has the variable payload size; the amplitude and phase of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value are received from the UE in the second part of the CSI report, which has the variable payload size.

[0024] In yet another implementation of this method thesignalingconfiguration parameter is a configuration parameter defining: UL transmission configuration; DL transmission configuration; whether DL transmission is performed in SU-MIMO mode or in MU-MIMO mode; a type of codebook applied; one or more codebook parameters applicable to DL transmission; a periodicity of transmission of reference signals by the BS; or a periodicity of CSI reporting to the BS; and wherein theCSI calculationconfiguration parameter is a configuration parameter defining: whether the CSI should be obtained using a codebook or based on the reciprocity principle of the UL and DL channels, according to which the channel estimation is performed by the BS based on SRSs; whether the UE should estimate and report one or more components of the CSI respectively as one or more values for the entire frequency band (wideband estimation / reporting) of the CSI or for each of the subbands (subband estimation / reporting), or a size of the subband for the subband estimation / reporting.

[0025] Provided in the second aspect of the present invention is the base station comprising operatively coupled a transceiving unit, an antenna array, a processor, and a readable medium storing processor executable instructions which, when executed by the processor, cause the base station to perform the method according to the first aspect of the present invention or according to any implementation of the first aspect of the present invention.

[0026] Provided in the third aspect of the present invention is the computer-readable medium storing executable instructions that, when executed by a device, cause the device to perform the method according to the first aspect of the present invention or according to any implementation of the first aspect of the present invention.

[0027] Provided in the fourth aspect of the present invention is the method implemented by UE of communication with BS, in which channel properties are taken into account, the method comprising the steps of: receiving one or more reference signals, wherein the reference signal is the CSI-RS; calculating, when estimating the channel based on said one or more reference signals, at least one SDCP value and / or at least one FDCP value, wherein the SDCP value represents spatial domain channel correlation corresponding to at least some CSI-RS antenna ports, and the FDCP value represents frequency domain channel correlation corresponding to at least some subcarriers of the CSI-RS antenna port; transmitting to the BS in CSI report the calculated at least one SDCP value and / or at least one FDCP value; and receiving from the BS at least one value of one or more values of, respectively, one or more configuration parameters from among signaling configuration parameters and CSI calculation configuration parameters.

[0028] In one implementation, the method further comprises the step of: receiving, from the BS, DL transmission that is configured based on the one or more values, respectively, of one or more signaling configuration parameters determined based on the at least one SDCP value and / or the at least one FDCP value.

[0029] In yet another implementation of said method, said at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, carry the CSI-RS or TRS; and said at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, are located in one or more PRBs located in one or more adjacent time resources, for example, but not limited to, in the same OFDM slot.

[0030] In another implementation, the method further comprises the steps of: calculating at least one TDCP value, wherein the TDCP value represents a time domain channel correlation corresponding to OFDM symbols in one or more OFDM slots; transmitting to the BS the at least one TDCP value to enable at the BS the determination of the one or more values of, respectively, the one or more configuration parameters from signaling configuration parameters and CSI calculation configuration parameters further based on the at least one TDCP value.

[0031] In yet another implementation of said method, one or more of a number, a periodicity of transmission and a type of said one or more CSI-RS, and values of what channel property(properties) from among SDCP, FDCP, TDCP are to be calculated at the UE and reported to the BS in the CSI report, are configured in advance; or the signaling of one or more of a number, a periodicity of transmission and a type of said one or more CSI-RS, and values of what channel property(properties) from among SDCP, FDCP, TDCP are to be calculated at the UE and reported to the BS in the CSI report is received at the UE using the radio resource control (RRC) protocol, downlink control information (DCI) or the medium access control (MAC) layer.

[0032] In another implementation of said method, said method further comprises the step of: one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value are quantized in amplitude and / or quantized in phase before being transmitted to the BS, wherein whether the calculation of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value should be performed with amplitude quantization or with amplitude and phase quantization is configured in advance; or the method further comprises the step of: the signaling whether the calculation of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value should be performed with amplitude quantization or with amplitude and phase quantization is received at the UE using the RRC protocol, MAC layer, or DCI.

[0033] In yet another implementation of said method, spacing of said at least some CSI-RS antenna ports over a first dimension and / or a second dimension for calculating the corresponding spatial domain channel correlation values are configured in advance; or the method further comprises the step of: the signaling of the spacing of said at least some CSI-RS antenna ports is received at the UE using the RRC protocol, MAC layer, or DCI.

[0034] In another implementation of said method, spacing of said at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, over a single PRB or several PRBs is configured in advance, or the method further comprises the step of: the signaling of the spacing of said at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, over a single PRB or several PRBs is received at the UE using the RRC protocol, MAC layer, or DCI.

[0035] In yet another implementation of said method the phase of the correlation coefficient is uniformly quantized using phase shift keying (PSK) constellation, and the amplitude of the correlation coefficient is uniformly quantized in logarithmic scale domain.

[0036] In yet another implementation of said method one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is(are) transmitted to the BS in a first part of the CSI report, which has a fixed payload size; and / or one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is(are) transmitted to the BS in a second part of the CSI report, which has a variable payload size.

[0037] In yet another implementation, said method further comprises one or more steps of: the amplitude of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is transmitted to the BS in the first part of the CSI report, which has the fixed payload size; the phase of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is transmitted to the BS in the first part of the CSI report, which has the fixed payload size; the amplitude and phase of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value are transmitted to the BS in the first part of the CSI report, which has the fixed payload size; the amplitude of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is transmitted to the BS in the second part of the CSI report, which has the variable payload size; the phase of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value is transmitted to the BS in the second part of the CSI report, which has the variable payload size; the amplitude and phase of one or more of the at least one SDCP value, the at least one FDCP value, the at least one TDCP value are transmitted to the BS in the second part of the CSI report, which has the variable payload size.

[0038] Provided in the fifth aspect of the present invention is the user equipment comprising operatively coupled a transceiving unit, an antenna array, a processor, and a readable medium storing processor executable instructions which, when executed by the processor, cause the user equipment to perform the method according to the fourth aspect of the present invention or according to any implementation of the fourth aspect of the present invention.

[0039] Provided in the sixth aspect of the present invention is the computer-readable medium storing executable instructions that, when executed by a device, cause the device to perform the method according to the fourth aspect of the present invention or according to any implementation of the fourth aspect of the present invention.

[0040] Provided in a seventh aspect of the present invention is the communication system comprising at least one base station according to the second aspect of the present invention or according to any implementation of the second aspect of the present invention and at least one user equipment according to the fifth aspect of the present invention or according to any implementation of the fifth aspect of the present invention, wherein said at least one base station and said at least one user equipment communicate with each other.

[0041] Methods and apparatuses for enhanced reporting of channel properties for communication systems that employ massive MIMO or extremely massive MIMO (X-MIMO) technology in a wireless communication system are provided.

[0042] These and other aspects and non-limiting embodiments of the present invention, as well as advantageous technical effects, will be described in detail below with reference to the attached drawings, in which:

[0043] Fig. 1 illustrates three non-limiting implementations a)-c) of the method of communication between BS and UE according to the present invention.

[0044] Fig. 2a illustrates three non-limiting implementations a)-c) of calculating FDCP over reference signal structures of three types: single-port TRS, multi-port CSI-RS and single-port CSI-RS, according to the present invention.

[0045] Fig. 2b illustrates three non-limiting implementations a)-c) of calculating FDCP over reference signal structures of three types: single-port TRS, multi-port CSI-RS and single-port CSI-RS, according to the present invention.

[0046] Fig. 2c illustrates three non-limiting implementations a)-c) of calculating FDCP over reference signal structures of three types: single-port TRS, multi-port CSI-RS and single-port CSI-RS, according to the present invention.

[0047] Fig. 3 illustrates two non-limiting implementations of quantizing the amplitude of the correlation FDCP-coefficient and two non-limiting implementations of quantizing the phase of the correlation FDCP-coefficient according to the present invention.

[0048] Fig. 4 illustrates a non-limiting implementation of calculating SDCP according to the present invention.

[0049] Fig. 5 illustrates the non-limiting implementation of spacing CSI-RS antenna ports over the first dimension and over the second dimension for calculating SDCP, as well as two non-limiting implementations for quantizing the amplitude of the correlation SDCP-coefficient and two non-limiting implementations for quantizing the phase of the correlation SDCP-coefficient according to the present invention.

[0050] Fig. 6 illustrates the non-limiting implementations of reporting the amplitude and / or phase of the channel correlation FDCP and / or SDCP coefficients in the CSI report according to the present invention.

[0051] Fig. 7 illustrates the non-limiting implementation of calculating TDCP according to the prior art.

[0052] Fig. 8 illustrates the non-limiting schematic representation of the BS 200 according to the present invention.

[0053] Fig. 9 illustrates the non-limiting schematic representation of the UE 400 according to the present invention.

[0054] Fig. 10 illustrates the non-limiting schematic representation of the communication system 500 according to the present invention.

[0055] Figs. 1-6, 8-10 described in detail below, and the various implementations used to describe the principles of the present disclosure in this patent document are provided herein for illustrative purposes only and should not be construed in any way as limiting the scope of this disclosure. Those skilled in the art will appreciate, upon review of this disclosure, that the principles of the disclosed invention may be implemented in any suitably configured system or device.

[0056] Before proceeding to the detailed description of the present invention, some terms that are widely used in this patent document will be defined. The terms "transmit", "receive" and "communicate" and their derivatives cover both direct communication and indirect communication, such as through a third or any subsequent element that may not be stated explicitly. The terms "include" and "comprise" and their derivatives mean inclusion without limitation, i.e., in the actual implementation there may be other elements / operations not explicitly listed after such terms. The wording of features as "A and / or B" suggests the following possible options: only A, only B, A and B. The phrase "at least one", when used with a list of elements / operations, means that various combinations of one or more of the listed elements / operations can be used, but also that only one element from the list will suffice for a particular embodiment. For example, "at least one of: A, B and C" covers one of: A; B; C; A and B; A and C; B and C; and A and B, and C. Functionality associated with any unit of the device or with the whole device, or with a step of the method, can be centralized or distributed, and performed locally or remotely. When used in this document, such terms as "first" and "second", etc., may be used simply to distinguish one instance of a component from another instance of the component, and do not limit the components in any other way (such as by importance or order). The terms "FDCP value" and the more precise term "frequency domain channel correlation coefficient" may be used interchangeably herein. The terms "SDCP value" and the more precise term "spatial domain channel correlation coefficient" may be used interchangeably herein. The terms "TDCP value" and the more precise term "time domain channel correlation coefficient" may be used interchangeably herein. Similarly, the terms "data transmission channel", "data channel", "channel" may be used herein interchangeably with the terms "communication line", "data transmission line".

[0057] When used herein, any component described as part of a hardware device shall be considered as a unit implemented in hardware, software, or firmware, or a combination thereof, and another derivative term such as "module," "logic," "logical block," "part," or "circuit" may be used interchangeably in place of the term "unit" to refer to such a component. For example, according to an embodiment, a device component may be implemented in the form of an application specific integrated circuit (ASIC).

[0058] In addition, the various functions described below may be implemented or supported by one or more computer-executable instructions / computer programs, each of which is formed from computer-readable program code stored on a computer-readable medium, and can be executed, when required, by a processor of the device. The terms "program" / "application" mean one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or a portion thereof, adapted for implementation in suitable computer-readable program code. The phrase "computer-readable program code" includes any type of machine code, including source code, object code, and executable code. The phrase "computer-readable medium" or "machine-readable medium" includes any type of medium that can be accessed and read / written by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard disk, compact disc (CD), digital versatile disc (DVD), or any other type of storage device. "Non-transitory" computer-readable medium excludes wired, wireless, optical, or other communications links that carry transient electrical or other signals. Non-transitory computer-readable storage medium includes medium on which data can be permanently stored and medium on which data can be stored and subsequently rewritten, such as a rewritable optical disc or an erasable memory device.

[0059] Definitions for other specific words and phrases will be provided throughout this description as deemed useful to provide a clear understanding of the subject matter of this disclosure. Those skilled in the art will appreciate that in many, if not most, instances, such definitions apply to prior as well as future uses of such defined words and phrases. In cases where an explicit definition of a term is not given in this description, it is assumed that this term is used in the meaning generally used in the relevant technical field.

[0060] Fig. 1 illustrates three non-limiting implementations a)-c) of BS and UE communication according to the present invention. Let us start the description with the implementation a). The communication of the BS 200 and the UE 400 according to implementation a) begins with step S100, in which the BS 200 transmits one or more reference signals. The reference signal applicable for the purposes of the present invention may be a multi-port CSI-RS (implementation b in Fig. 2), a single-port CSI-RS (implementation c in Fig. 2) and a single-port TRS (implementation a in Fig. 2), but here they are all called CSI-RSs, since TRSs, which represent sparse reference signals intended to track and compensate for time and frequency offsets of the signal being received at the UE side, are a particular type of CSI-RSs.

[0061] As shown in Fig. 1, reference signals 1-N are transmitted in DL resources identified as DL resources 1-N, respectively. The number and periodicity of sending reference signals over the DL are configurable parameters. Then, according to implementation a) of Fig. 1 the UE 400 receives at the step S200 one or more reference signals transmitted from the BS 200 and performs at the step S205 calculation of at least one channel property value in the frequency domain (FDCP value) between the BS 200 and the UE 400. The calculation of the FDCP value can be performed at the UE 400 as part of the process of evaluating CSI based on CSI-RSs, or as a separate operation performed before or after such an evaluation.

[0062] The FDCP value is the frequency correlation of the channel, expressed by the correlation coefficient and corresponding to the correlation between at least some subcarriers of the CSI-RS antenna port. The CSI-RS antenna port is defined by a predefined sequence modulating specific subcarriers according to the CSI-RS structure described in the specification (see, for example, section 7.4.1.5 of 3GPP TS 38.211 v18.3.0). Knowing the structure of the CSI-RS antenna port reference signal transmitted by the BS allows the UE to evaluate the channel between the BS and the UE and to measure various additional characteristics.

[0063] At step S205, the UE 400 may calculate one or more FDCP values. If multiple FDCP values are calculated, each of these values will be calculated between the subcarriers of a specific pair of CSI-RS antenna port subcarriers, and the pairs of CSI-RS antenna port subcarriers over which the corresponding FDCP values are calculated will be different from each other. Calculating multiple FDCP values for a communication channel allows the UE 400 to obtain more complete information about the channel correlation in the frequency domain for different subcarrier spacing values. In the non-limiting example, CSI frequency subband size may be determined from multiple FDCP values by comparing the obtained values with a predetermined threshold value and selecting a subband size equal to the maximum spacing that provides channel correlation values in the frequency domain above said threshold value.

[0064] Next, according to the implementation a) of Fig. 1, the UE 400 transmits at step S210 to the BS 200 the calculated at least one FDCP value in the CSI report, and the BS 200 accordingly receives at step S105 this information. Alternatively, the calculated at least one FDCP value may be transmitted in FDCP report, which may be included in the CSI report or transmitted separately from the CSI report. Thereafter, the BS 200, at step S110, determines one or more values of one or more configuration parameters from signaling configuration parameters and CSI calculation configuration parameters based on the at least one FDCP value received from the UE. Non-limiting implementation examples of the determination of specific configuration parameters based on the channel frequency correlation coefficient, as well as the justification of the dependencies of these parameters on the said coefficient, will be described further in the text of this specification immediately after the description of all implementations a)-c) illustrated in Fig. 1. Thereafter, the BS 200 transmits at step S115 to the UE 400, and the UE 400 accordingly receives at step S215, the determined one or more values of the one or more configuration parameters, which is (are) to be applied at the UE 400 to configure signaling between the BS 200 and the UE 400 and / or configure CSI calculation at the UE 400. Alternatively and in addition, the BS 200 may itself apply the determined one or more values of the one or more signaling configuration parameters to configure the DL transmission (for example, but not limited to, to configure the DL transmission performed at step S115).

[0065] Next, let us turn to the description of implementation b) according to Fig. 1. This implementation differs from implementation a) according to Fig. 1 in that, instead of calculating the FDCP value, the UE 400 carries out, at step S205, the calculation of at least one channel property value in spatial domain (SDCP value) between the BS 200 and the UE 400. The calculation of the SDCP value can be performed at the UE 400 as part of the process of evaluating CSI based on CSI-RSs, or as a separate operation performed before or after such an evaluation. The SDCP value is the spatial correlation of the channel, expressed by the correlation coefficient and corresponding to the correlation between at least some CSI-RS antenna ports. At this step the UE 400 may calculate one or more SDCP values. If multiple SDCP values are calculated, each of these values will be calculated between two or more CSI-RS antenna ports with a specified spatial spacing between them. Calculating multiple SDCP values for the communication channel allows the UE 400 to obtain more complete information about the channel correlation in the spatial domain across two dimensions and different values of spatial spacing of the CSI-RS antenna ports. In the non-limiting example, the number of Discrete Fourier Transform (DFT) vectors used to quantize a precoding matrix may be determined from multiple SDCP values by determining a maximum spacing of CSI-RS antenna ports having a correlation below a predetermined threshold value.

[0066] Next, according to the implementation b) of Fig. 1, the UE 400 transmits at step S210 to the BS 200 the calculated at least one SDCP value in the CSI report, and the BS 200 accordingly receives at step S105 this information. Alternatively, the calculated at least one SDCP value may be transmitted in SDCP report, which may be included in the CSI report or transmitted separately from the CSI report. Thereafter, the BS 200, at step S110, determines one or more values of one or more configuration parameters from among signaling configuration parameters and CSI calculation configuration parameters based on the at least one SDCP value received from the UE 400. Non-limiting implementation examples of the determination of specific configuration parameters based on the channel spatial correlation coefficient, as well as the justification of the dependencies of these parameters on the said coefficient, will be described further in the text of this specification immediately after the description of all implementations a)-c) illustrated in Fig. 1. Thereafter, the BS 200 transmits at step S115 to the UE 400, and the UE 400 accordingly receives at step S215, the determined one or more values of the one or more configuration parameters, which is (are) to be applied at the UE 400 to configure signaling between the BS 200 and the UE 400 and / or configure CSI calculation. Alternatively and in addition, the BS 200 may itself apply the determined one or more values of the one or more signaling configuration parameters to configure the DL transmission (for example, but not limited to, to configure the DL transmission performed at step S115).

[0067] Next, let us turn to the description of implementation c) according to Fig. 1. In this implementation c), the UE 400 carries out at step S205 the calculation of both at least one FDCP value and at least one SDCP value. The calculation of the FDCP and SDCP values can be performed at the UE 400 as part of the process of evaluating CSI based on CSI-RSs, or as a separate operation performed before or after such an evaluation. At this step the UE 400 may calculate one or more FDCP values and one or more SDCP values. If multiple FDCP and SDCP values are calculated, each of these values will be calculated between different CSI-RS antenna port subcarriers and different CSI-RS antenna ports, respectively. The CSI-RS antenna port subcarrier spacing for FDCP value calculation and the CSI-RS antenna port spatial spacing for SDCP value calculation are configurable parameters. Calculating both the FDCP value(s) and the SDCP value(s) for the communication channel allows the UE 400 to measure the channel more completely in both the frequency domain and the spatial domain.

[0068] Next, according to the implementation c) of Fig. 1, the UE 400 transmits at step S210 to the BS 200 the calculated at least one FDCP value and the calculated at least one SDCP value in the CSI report, and the BS 200 accordingly receives this information at step S105. Thereafter, the BS 200, at step S110, determines one or more values of one or more configuration parameters from among signaling configuration parameters and CSI calculation configuration parameters based on the at least one FDCP value and the at least one SDCP value received from the UE 400. Non-limiting implementation examples of the determination of specific configuration parameters based on the channel frequency and spatial correlation coefficients, as well as the justification of the dependencies of these parameters on the said coefficients, will be described further in the text of this specification immediately after the description of all implementations a)-c) illustrated in Fig. 1. Thereafter, the BS 200 transmits at step S115 to the UE 400, and the UE 400 accordingly receives at step S215, the determined one or more values of the one or more configuration parameters, which is (are) to be applied at the UE 400 to configure signaling between the BS 200 and the UE 400 and / or configure CSI calculation at the UE 400. Alternatively and in addition, the BS 200 may itself apply the determined one or more values of the one or more signaling configuration parameters to configure the DL transmission (for example, but not limited to, to configure the DL transmission performed at step S115).

[0069] Any of the above-described implementations a)-c) may be modified by additionally calculating at the UE 400 side at step S205 at least one TDCP value known from the 5G NR prior art and additionally reporting at step S210 this at least one TDCP value to the BS 200 to take it into account additionally when determining by the BS 200 at step S110 one or more values of one or more configuration parameters. As shown in Fig. 7, the TDCP value represents the time domain channel correlation corresponding to OFDM symbols in one or more OFDM slots and is related to the mobility of the UE 400 (i.e., the speed with which the UE 400 is moved). More detailed information regarding the TDCP, which in some embodiments of the present invention may be calculated in addition to FDCP and SDCP, is disclosed in section 5.1.45 of 3GPP TS 38.215, Rel-18.

[0070] In this way, the UE 400 calculates one or more of FDCP value, SDCP value, TDCP value and transmits these one or more values to the BS 200, which in turn, based on these values, determines one or more values, respectively, of one or more configuration parameters. Alternatively and additionally, an embodiment (not shown) may be provided in which the UE 400 itself calculates the value of at least one configuration parameter (for example, but not limited to, the value of DL transmission configuration parameter) and transmits this already calculated value of the configuration parameter to the BS 200 for its application.

[0071] The configuration parameters, the values of which the BS 200 and / or UE 400 may calculate based on one or more of the FDCP value, the SDCP value, the TDCP value and apply, may generally be any configuration parameters, but in a preferred embodiment, the configuration parameters include (1) signaling configuration parameters and (2) CSI calculation configuration parameters.

[0072] By way of example, and not limitation, thesignalingconfiguration parameter may be any one of the configuration parameters defining: (a) UL transmission configuration, (b) DL transmission configuration, (c) whether DL transmission is performed in SU-MIMO mode or in MU-MIMO mode, (d) a type of codebook applied, (e) one or more codebook parameters applicable to DL transmission, (f) a periodicity of transmission of reference signals by the BS, (g) a periodicity of CSI reporting to the BS, etc.

[0073] By way of example, and not limitation, theCSI calculationconfiguration parameter may be any one of the configuration parameters defining: (h) whether the CSI should be obtained using a codebook or based on the reciprocity principle of the UL and DL channels, according to which the channel estimation is performed by the BS based on SRSs; (i) whether the UE should evaluate and report one or more components of the CSI respectively as one or more values for the entire frequency band (wideband evaluation / reporting) of the CSI or for each of the subbands (subband evaluation / reporting), (j) a size of the subband for the subband evaluation / reporting, etc.

[0074] The components of the CSI that may be calculated by the UE include, but are not limited to: CQI (Channel Quality Indicator) is a channel quality indicator that reflects the channel quality that the UE measures based on CSI-RSs; PMI (Precoding Matrix Indicator) is an indicator of the precoding matrix, indicating the proposed precoding matrix; RI (Rank Indicator) is a rank indicator that indicates the number of independent data streams (or ranks) that can be transmitted simultaneously on different spatial channels; LI (Layer Indicator) is a layer indicator indicating the index of the layer with the best channel quality; CRI (CSI-RS Resource Indicator) is CSI-RS resource indicator indicating the CSI-RS resource that was used to measure CSI; SSBRI (SS / PBCH Block Resource Indicator) is indicator of preferred resource for SS / PBCH.

[0075] It is well known that in multipath channels with low angular spread of the channel, the Type 1 codebook provides high efficiency of quantization of CSI (precoding matrix) with minimal overhead of its transmission to the BS (see, e.g., the article "A Review of Codebooks for CSI Feedback in 5G New Radio and Beyond" by Ziao Qin, Haifan Yin, published in February 2023). In turn, such channels are characterized by relatively high spatial correlation. In contrast, for a channel with high angular spreads, the spatial correlation of the channel is significantly reduced and the most efficient approach to quantizing CSI is to use Type 2 or eType 2 codebook. In this case, the optimal choice between using Type 1 or Type 2 codebook may be based on one or more SDCP values. In a non-limiting example, Type 1 codebook may be configured by the BS for the UE if the UE-calculated spatial domain correlation coefficients (i.e., SDCP values) between the CSI-RS antenna ports are above certain threshold values predefined at the BS. Otherwise, the BS may configure Type 2 (or eType 2) codebook for the UE.

[0076] A similar threshold-based method may be used to determine parameters of Type 2 codebook, such as the number L of DFT vectors (see, for example, section 5.2.2.2.5 of 3GPP TS 38.214 v18.3.0) used by the UE to quantize the CSI (precoding matrices). For example, the largest number (e.g., L=6) of DFT vectors may be configured by the BS for the UE having the SDCP value (for a minimum port spacing; for example, the spacing equal to one antenna port, in which the correlation is actually calculated between adjacent antenna ports along a certain dimension) less than a first threshold value determined in advance at the BS; the middle number (e.g., L=4) of DFT vectors may be configured by the BS for the UE having the SDCP value (for a middle port spacing; for example, the spacing equal to half the number of ports along the corresponding dimension: floor( / 2) and floor( / 2), where , are numbers of ports along the first and second dimensions, respectively, the floor() is the operation for rounding to the smallest nearest integer) less than a second threshold value determined in advance at the BS; and the smallest number (e.g., L=2) of DFT vectors may be configured by the BS for the UE having the SDCP value (for a maximum port spacing; for example, the spacing equal to the maximum spacing minus 1 along the first dimension and / or for the maximum spacing minus 1 along the second dimension) less than a third threshold value determined in advance at the BS.

[0077] The frequency domain channel correlation indicated by the calculated FDCP values may be used to determine and configure for the UE, for example, CSI frequency subband size by comparing the calculated FDCP values with a predetermined threshold value and selecting a subband size equal to the maximum frequency spacing of the subcarriers that provides frequency domain channel correlation values above said threshold value. In a similar manner, the number Mvof DFT vectors (see, for example, section 5.2.2.2.5 of 3GPP TS 38.214 v18.3.0) to be used by the UE for frequency domain quantization of the precoding matrix of the eType 2 codebook may be determined and configured by the BS for the UE.

[0078] In addition, to effectively utilize MU-MIMO modes when the BS simultaneously transmits multiple signals to multiple users, the BS suppresses mutual interference using adaptive beamforming. But said BS cannot change the precoding matrix (the precoder) in the frequency domain with sufficient granularity, so for the BS to effectively exploit this mode, it would also be useful to know the frequency channel correlation (FDCP) measured at the UE, which is directly related to the channel dispersion in the time domain, i.e. how many beams with different delays are present in the channel between the BS and the UE.

[0079] In another non-limiting example, for DMRSs a parameter that controls how densely the DMRSs should follow in the frequency domain may be used. And, naturally, it would be useful for the BS to know the frequency channel correlation in order to decide how dense the DMRS should be in the frequency domain so that the UE can determine the channel values in the frequency domain with sufficient accuracy. In addition, the decision at the BS as to whether the UE should estimate and report one or more components of the CSI, respectively, by one or more values for the entire frequency range (wideband estimation / reporting) of the CSI or for each of the subbands (subband estimation / reporting), and as to the size of the subband in the case of subband estimation / reporting, also depends on the frequency correlation of the channel. In other words, the wideband CSI estimation / reporting may be configured by the BS if the UE-calculated frequency correlation coefficients (i.e., FDCP values) are above a predetermined threshold value, and otherwise the subband CSI estimation / reporting with a predetermined subband size may be configured, or vice versa.

[0080] With regard to the dependence of the configuration parameters on the time domain channel correlation indicated by the calculated TDCP values, it is known that the time domain channel correlation is affected by user mobility, i.e. the speed at which the UE moves in space. In particular, as the UE mobility increases, the channel correlation in the time domain decreases, and vice versa. Based on this, when the UE-calculated TDCP value passes a predetermined TDCP threshold value determined in advance at the BS, the BS can switch the CSI calculation modes: from the CSI calculation mode using the codebook (this mode is most beneficial for relatively fast moving UEs) to the CSI calculation mode via the SRS (this mode is most beneficial for UEs moving at a low speed (for example, at a speed not exceeding approximately 10 km / h) or for stationary UEs) taking into account the reciprocity of the DL and UL channels, and vice versa. In yet another non-limiting example, when the UE-calculated TDCP value passes a predetermined TDCP threshold value determined in advance at the BS, the base station may switch the type of codebook used: from Type 2 codebook (said type is more advantageous when the UE has relatively low mobility, e.g. when the UE has a mobility of less than or equal to 10 km / h) to Type 1 codebook (said type is more advantageous when the UE has higher mobility), and vice versa.

[0081] The above-described non-limiting examples and other, not explicitly mentioned, dependencies of the optimal values of the configuration parameters (a)-(j) on the coefficients of (frequency and / or spatial and / or temporal) channel correlation will be clear to persons having ordinary skill in the art. In addition, in this application, the term "optimal", when used as a characteristic of a particular value of a configuration parameter, may depend on the current configuration and state of the communication network, the configuration and state of the UE, and the configuration and state of the BS. Thus, the optimal values of configuration parameters for a given situation can be predefined / redefined by the network operator or equipment manufacturer. Therefore, the present invention, at least in terms of how exactly the determination of the values of the configuration parameters can be performed based on one or more of at least one SDCP value, at least one FDCP value, at least one TDCP value, should not be limited solely by the logic of such determination in the above examples.

[0082] Fig. 2 illustrates three non-limiting implementations a)-c) of calculating FDCP over three types of reference signal structures: single-port TRS, multi-port CSI-RS and single-port CSI-RS, according to the present invention. However, one of ordinary skill in the art will appreciate that the principles of the present invention may be applied to other reference signals, including reference signals that may be introduced in a next-generation communication standard (e.g., 6G). Thus, the reference signal structures of the three specific types shown in Fig. 2 should be considered as non-limiting examples of the implementation of the present invention, and not as a limitation of the present invention.

[0083] The FDCP value is calculated as a complex value of the channel frequency correlation according to equation 1, the modulus of this complex value will determine the amplitude of the channel frequency correlation, and the argument of this complex value will determine the phase of the channel frequency correlation:

[0084] [Equation 1]

[0085]

[0086] where is the spacing of the subcarriers between which the FDCP value is calculated,

[0087] is a set of resource blocks used to calculate the FDCP value, which are either reported to the UE in advance by the BS or are defined by default in the specification,

[0088] , are the indices of the antenna array ports, respectively, along the 1st and 2nd dimensions, specifying the CSI-RS antenna port for channel measurements (for single-port CSI-RS or for single-port TRS, these indices are not used), and

[0089] is channel complex value obtained by the UE using CSI-RS for the -th resource block for antenna array ports having indices , .

[0090] Implementation a) shown in Fig. 2 relates to the calculation of the FDCP value over the subcarriers of a single-port TRS. Single-port TRS is transmitted every fourth subcarrier. Thus, by combining the frequency offset that defines the spacing of the subcarriers between which the channel frequency correlation is calculated, within one PRB (with an offset of either 4 subcarriers or 8 subcarriers), or between different PRBs (including with an offset of 4 or 8 subcarriers; for example, with the product of the channels in the equation 1 for the channels according to Fig. 2 (a) with subcarrier 10 and with subcarrier 14 (offset 4), respectively, or with subcarrier 10 and with subcarrier 18 (offset 8), which in both examples are in different PRBs), according to the equation 2 it is possible to configure how deep in the frequency domain the UE shall calculate the FDCP value (i.e. with what spacing between the subcarriers of the single-port TRS in the frequency domain the FDCP value should be calculated):

[0091] [Equation 2]

[0092]

[0093] The value indicating the spacing between TRS subcarriers in the frequency domain, which is to be applied in the calculation of the FDCP value at step S205 in this implementation a) may be configured for in advance or signaled to the UE 400 using the RRC protocol, the MAC layer, or in the DCI.

[0094] In non-limiting examples of this implementation a), illustrated on the left in Fig. 2, the calculation of the FDCP value may be performed: between the occurrence of the TRS in the resource element (2, 5), i.e. in the resource element in the second subcarrier of the fifth OFDM symbol, and any subsequent occurrence of the TRS in resource elements adjacent in frequency and / or time. In particular, Fig. 2 shows on the left three specific examples of calculating the FDCP value: the first, between subcarriers with subcarrier spacing ; the second, between subcarriers with subcarrier spacing (intra-PRB); the third, between subcarriers with subcarrier spacing (inter-PRB). But the present invention is not limited to these three examples.

[0095] Similarly, the subcarrier spacing may be defined when calculating the FDCP value over the subcarriers of a single-port CSI-RS (implementation c). This single-port CSI-RS is used in the 5G system and, like TRS, is transmitted in the frequency domain quite frequently (i.e. has a high density in the frequency domain). This type of single-port CSI-RS can be used both for CSI acquisition and in beam management procedure. Thus, the equations 1 and 2, given above for defining the subcarrier spacing and calculating the FDCP value, are also applicable to said implementation c). The value indicating the spacing between single-port CSI-RS subcarriers in the frequency domain, which is to be applied in the calculation of the FDCP value at step S205 in this implementation c) may also be configured for in advance or signaled to the UE 400 using the RRC protocol, the MAC layer, or in the DCI.

[0096] In yet another implementation b) shown in the center of Fig. 2, it is proposed to use conventional CSI-RSs, which are traditionally used to calculate the DFT vectors of the precoding matrix in the codebook, to calculate the FDCP value. Because these conventional CSI-RSs are multi-port, they are not transmitted as densely in the frequency domain as the single-port TRSs (implementation a) and single-port CSI-RSs (implementation c). Therefore, in this implementation b) the subcarrier spacing with which the channel frequency correlation is calculated according to equation 1 is defined according to the following equation 3:

[0097] [Equation 3]

[0098]

[0099] As follows from equation 3, and since a portion of the multi-port CSI-RS corresponding to one antenna port of the CSI-RS can be transmitted every PRB, the minimum subcarrier spacing in the frequency domain with which the UE 400 can calculate the FDCP value in this implementation b) is 12 subcarriers (1 PRB), and the maximum subcarrier spacing in the frequency domain with which the UE 400 can calculate the FDCP value in this implementation b) is 120 subcarriers (10 PRB).

[0100] It should be noted that in this implementation b) the FDCP value may be calculated over one or more, including all ports of the multi-port CSI-RS. When calculating the FDCP value over multiple ports, the calculated values can be additionally averaged over the corresponding ports. As the non-limiting example, Fig. 2 (b) shows the multi-port CSI-RS structure that involves transmitting the CSI-RS antenna port every 24 subcarriers (2 PRBs). Accordingly, with such a structure, resource elements with the spacing of 24 subcarriers will be used to calculate the FDCP value, i.e., resource elements 0, 24, 48, 72, etc. In another example (not shown in the figure), if the multi-port CSI-RS structure assumes that the CSI-RS antenna port is transmitted every 12 subcarriers (1 PRB, which is also possible given the equation 3 above), resource elements with the spacing of 12 subcarriers will be used to calculate the FDCP value in this example, i.e. resource elements 0, 12, 24, 36, etc. In yet another non-limiting example, the FDCP value may be calculated between subcarriers corresponding to predetermined CSI-RS ports and subcarriers corresponding to said predetermined CSI-RS ports in other PRBs, and then, optionally, the calculated values may be averaged over the corresponding ports. In another non-limiting example, which is the preferred one, the FDCP value may be calculated between subcarriers corresponding to all CSI-RS ports in certain PRBs and subcarriers corresponding to all CSI-RS ports in other PRBs, respectively, selected according to a predetermined frequency spacing. The specific CSI-RS antenna ports used to calculate the channel frequency correlation may be communicated to the UE via, for example, higher layer signaling (RRC, MAC).

[0101] Next, let us turn to the description of Fig. 3 illustrating two non-limiting implementations of quantizing the amplitude of the correlation FDCP-coefficient and two non-limiting implementations of quantizing the phase of the correlation FDCP-coefficient according to the present invention. Depending on the BS configuration, the UE may calculate and report to the BS amplitude value(s) of the channel correlation in the frequency domain, defined by the modulus (moduli) of the complex value , and / or phase value(s) of the channel correlation in the frequency domain, defined by the argument(s) of the complex value .

[0102] According to implementation a) shown in Fig. 3, the quantization of the amplitude values of the channel correlation in the frequency domain can be performed linearly on a logarithmic scale (log linear amplitude quantization) over 16 quantization levels {0-15} with a quantization resolution (granularity) equal to 4 bits, according to the expression defining the quantization levels. In this way, the calculated amplitude of channel correlation is quantized to a nearest quantization level . The proposed values of , applicable in this implementation a), as well as the corresponding amplitude quantization indices , are given in the table in Fig. 3 (a). Thus, each quantized amplitude value of the channel correlation in the frequency domain corresponds to its respective amplitude quantization index and a corresponding four-bit value. For example, the quantized amplitude value of the channel correlation in the frequency domain with the index may correspond to the bit value "0000", the quantized amplitude value of the channel correlation in the frequency domain with the index may correspond to the bit value "0001", etc. The resulting bit values of the quantized amplitude values of the channel correlation in the frequency domain may be reported to the BS in the CSI report or in the FDCP report that may be included in the CSI report or transmitted separately. Non-limiting examples of how bit values of quantized amplitude values of the channel correlation in the frequency domain may be communicated to the BS will be described below in the text of this specification with reference to Fig. 6.

[0103] Implementation b) for determining quantized amplitude values of the channel correlation in the frequency domain shown in Fig. 3 is less accurate because it differs from the described above implementation a) by the smaller quantization resolution of 3 bits. Thus, implementation b) has a coarser amplitude quantization, but, which is advantageous, contributes to a reduction in signaling overhead. However, the present invention should not be limited to the implementations a) and b) shown in Fig. 3, since it is clear that other implementations of quantization of the amplitude values are possible as well, for example both implementations with a quantization resolution exceeding 4 bits and the implementation with a quantization resolution equal to 2 bits.

[0104] According to implementations c) and d) shown in Fig. 3, the quantized phase values of the channel correlation in the frequency domain can be obtained using, respectively, 8-position phase shift keying (8-PSK) or 16-position phase shift keying (16-PSK) where is the phase quantization index. Implementation e) shown in Fig. 3 is possible as well, according to which the phase of the frequency domain channel correlation is not determined. Each quantized phase value of the channel correlation has its respective index and corresponding n-bit value, with 8-PSK n = 3, 16-PSK n = 4. The resulting bit values of the quantized phase values of the frequency domain channel correlation may be reported to the BS in the CSI report or in the FDCP report that may be included in the CSI report or transmitted separately. Non-limiting examples of how bit values of quantized phase values of the frequency domain channel correlation may be communicated to the BS will be described below in the text of this specification with reference to Fig. 6.

[0105] With reference to Figs. 4-5, implementations of calculating the SDCP as the correlation between predetermined CSI-RS antenna ports, as well as implementation s of quantizing the amplitude and phase of such correlation will now be described. However, the implementations that will be described below with reference to Fig. 4-5, should not be construed as a limitation of the present invention, but rather as non-limiting examples of implementations of the present invention.

[0106] The SDCP value is calculated as a complex value of the channel spatial correlation according to equation 4, the modulus of this complex value will determine the amplitude of the channel spatial correlation, and the argument of this complex value will determine the phase of the channel spatial correlation:

[0107] [Equation 4]

[0108]

[0109] where represents the spacing of the CSI-RS antenna ports along the first dimension and the second dimension for calculating the channel spatial correlation, the values of these parameters can be configured by the BS for the UE using, for example, the higher layer signaling (RRC, MAC),

[0110] [Equation 5]

[0111]

[0112] [Equation 6]

[0113]

[0114] , are running indices on the ports of the antenna array for the 1st and 2nd dimensions, respectively,

[0115] is a set of resource blocks used to calculate the SDCP value, which are either reported to the UE in advance by the BS or are defined by default in the specification, and

[0116] is channel complex value obtained by the UE using CSI-RS for thek-th resource block for antenna array ports having indices , .

[0117] Fig. 4 shows channel spatial correlation matrix calculated according to the equation 4, having a size , where is the number of CSI-RS antenna ports along the first dimension of the antenna array (16 ports in the non-limiting example of Fig. 4), and is the number of CSI-RS antenna ports along the second dimension of the antenna array (8 ports in the non-limiting example of Fig. 4).

[0118] Thus, according to equation 4, several exemplary implementations of SDCP calculation are possible. In the first non-limiting implementation example, the channel spatial correlation may be calculated between antenna elements of any pair. In this example, the specific pair(s) of CSI-RS antenna ports between which the correlation value is calculated can be predefined / configured by the BS for the UE. The correlation matrix R in this example can be as large as .

[0119] In the second non-limiting example, it is assumed that the channel spatial correlation is the same between antenna elements with the same indices along the first and second dimensions, but with different polarizations, i.e. the channel spatial correlation is calculated according to equations 4-6 only taking into account the spacing of the ports along the first dimension and the spacing of the ports along the second dimension (i.e. without taking into account the polarization). The correlation matrix R in this example can be as large as .

[0120] In the third non-limiting example, it is assumed that the channel spatial correlation between any two ports (antenna ports of one or more possible (configurable) pairs) with a specific spacing along one dimension of the antenna array does not depend on the index of these ports along the other dimension of the antenna array, and also does not depend on the polarization as in the second example described above. In fact, in this implementation, two matrices of correlation values are calculated: the first one has a dimension up to , the second one has a dimension up to . In this implementation, the UE can calculate the correlation not for all pairs of CSI-RS ports, but only for those pairs that are configured by the BS (for example, between adjacent CSI-RS antenna ports, or between CSI-RS antenna ports spaced by a specific value).

[0121] Fig. 5 shows, in the center and on the right, implementations of quantization of amplitude and phase of SDCP according to the present invention. The implementations of quantizing the amplitude and phase of the channel spatial correlation are similar to the implementations of quantizing the amplitude and phase of the channel frequency correlation described above with reference to Fig. 3, so the description of these implementations is not given here again.

[0122] Now, with reference to Fig. 6, proposed are several non-limiting implementations of reporting the UE-calculated FDCP and / or SDCP values in CSI report that is sent by the UE 400 to the BS 200 based on the results of the channel measurement performed by the UE 400 on the CSI-RS and the above-described calculation of the channel frequency and / or spatial correlation values according to the present invention. The transmission comprises two parts: the first part (part 1) of fixed size and the second part (part 2) of variable size, in each of which the payload may be transmitted, including, but not limited to, FDCP and / or SDCP values (and, optionally, TDCP value), and / or channel measurement results obtained by the UE 400.

[0123] In the implementation shown at the top of Fig. 6, it is assumed that the FDCP value(s) and / or the SDCP value(s) are included in part 1 as at least a portion of the fixed-size payload carried in part 1. It is assumed that the SDCP value(s) may be reported separately for the first dimension of digital antenna ports of the antenna array and for the second dimension of digital antenna ports of the antenna array. In this implementation, the remaining portion of part 1 of the fixed-size payload, and part 2 of the variable-size payload can be used to transmit any other payload.

[0124] In the implementation shown at the bottom of Fig. 6, it is assumed that the amplitude of the FDCP value(s) and / or the SDCP value(s) is included in part 1 as at least a portion of the fixed-size payload carried in part 1, and the phase of the FDCP value(s) and / or the SDCP value(s) is included in part 2 as at least a portion of the variable-size payload carried in part 2. In this implementation, the remaining portion of part 1 of the fixed-size payload and the remaining portion of part 2 of the variable-size payload can be used to transmit any other payload.

[0125] Thus, report configurations that use only part 1 are possible, in which in part 1: FDCP and / or SDCP are reported; the reported FDCP and / or SDCP information includes amplitude and / or phase information; the reported FDCP and / or SDCP information is multiplexed with CSI. In addition, the report configurations that use both parts 1 and 2 are possible, in which: FDCP and / or SDCP are reported in part 1 and part 2; part 1 includes the amplitude information of FDCP and / or SDCP and part 2 includes the phase information of FDCP and / or SDCP, or vice versa; FDCP and / or SDCP in parts 1 and 2 are multiplexed with any other payload, such as CSI. Any of these reporting formats may be predetermined in the specification or configured by the BS for the UE using RRC, MAC. In addition, using control information transmission (RRC, MAC, DCI), the BS may signal to the UE that, in addition to the amplitude, the phase of the FDCP and / or SDCP (and optionally TDCP) correlation needs to be determined and reported, or that it is not necessary to determine and report the phase of FDCP and / or SDCP correlation in addition to the amplitude (which allows reducing overhead by not including the correlation phase information in the transmission).

[0126] Fig. 7 illustrates the non-limiting implementation of calculating TDCP according to the prior art. As indicated above with reference to Fig. 1, the channel correlation value in time domain (TDCP value) may be further calculated in any one of the implementations of the present invention shown in Fig. 1. By analogy with the FDCP calculation, the TDCP value can be calculated from several occurrences of the TRS signal, but not in the frequency domain (as is the case for FDCP), but in the time domain, as shown in Fig. 7. The calculation of TDCP is known from the prior art (see, for example, section 5.1.45 of 3GPP TS 38.215).

[0127] Fig. 7 shows, as the non-limiting example, the structure of TRS signal from which the TDCP value can be calculated, and the exemplary TDCP calculation scheme, including non-limiting examples of OFDM symbol spacings . In the time domain, TRS occupies two OFDM symbols in one slot, which are spaced 4 OFDM symbols apart. Thus, as shown below in Fig. 7, TRS transmission may occupy not one but several slots. In the example of Fig. 7, the TRS transmission is performed in the first OFDM slot, the second OFDM slot, and the third OFDM slot. Fig. 7 at the top shows as the example that the channel correlation in time domain can be calculated between the first occurrence of TRS and the second occurrence of TRS, the third occurrence of TRS and the fourth occurrence of TRS, the fifth occurrence of TRS and the sixth occurrence of TRS, etc., in all these examples the spacing will be 4 OFDM symbols ( ), or between the first occurrence of TRS and the third occurrence of TRS, between the second occurrence of TRS and the fourth occurrence of TRS, between the third occurrence of TRS and the fifth occurrence of TRS, between the fourth occurrence of TRS and the sixth occurrence of TRS, etc., in all these examples the spacing will be 14 OFDM symbols ( ), or between the first occurrence of TRS and the fourth occurrence of TRS in the time domain, between the third occurrence of TRS and the sixth occurrence of TRS in the time domain, etc., in all these examples the spacing will be 18 OFDM symbols ( ), etc.

[0128] In other words, the BS itself, at its own discretion, i.e. depending on a specific mode, can inform the UE 400 about the depth to which the channel correlation in the time domain should be calculated based on the occurrences of TRS, and use this information on the channel correlation in time domain between the corresponding OFDM symbols to select a codebook or a mode for obtaining CSI, or to determine optimal values of other configuration parameters, as described above in the text of this specification.

[0129] Next, with reference to Fig. 8, an implementation of the BS 200 is described. The BS 200 comprises functionally coupled a transceiving unit 200.1, an antenna 200.2, a processor 200.3, and a readable medium 200.4 storing processor executable instructions which, when executed by the processor, cause the BS to perform the communication method according to the first aspect of the present invention or according to any development of the first aspect of the present invention. The BS 200 may be implemented as follows, but not limited to: Node B, eNodeB, gNodeB.

[0130] The transceiving unit 200.1 and the antenna 200.2 can be adapted, but not limited to the mentioned band, for operation in the upper mid-frequency band (7-13 GHz). The transceiving unit 200.1 is configured to transmit and receive radio signals. It includes amplifiers, modulators, demodulators and other components needed to convert signals to and from radio frequency range. The transceiving unit 200.1 can support multi-channel data transmission using xMIMO technology, which can increase the throughput. The transceiving unit 200.1 and the antenna 200.2 are responsible for digital and analog precoding / decoding of the signal. The transceiving unit 200.1 and the antenna 200.2 support operation in time division duplex mode and frequency division duplex mode, and comply with 3GPP specifications.

[0131] The antenna 200.2 is configured to emit and receive radio signals transmitted and received by transceiving unit 200.1. The antenna can be made in the form of an adaptive antenna array (including an extremely massive antenna array), which allows steering the signal in a desired direction and minimizing interference. As an example and not a limitation, the antenna 200.2 may have 1024 antenna elements and 128 digital ports. In another example, the antenna 200.2 may have 3072 antenna elements and 256 digital ports. In yet another non-limiting example the antenna 200.2 may have 4096 antenna elements and 256 digital ports.

[0132] The processor 200.3 is responsible for processing all signals from all components of the BS 200 and for performing any step(s) of the above-described communication method according to the first aspect of the present invention or according to any development of the first aspect of the present invention. In other words, the processor 200.3 is configured to perform operations necessary to control the operation of the BS 200 and to execute executable instructions stored on the readable medium 200.4. The processor 200.3 in the BS 200 may be one or more of the following processors, but is not limited to the following types of processors: Central Processing Units (CPUs), which are general-purpose processors that perform basic computing tasks; Graphic Processing Units (GPUs), which are specialized processors for processing graphics and performing parallel computing; coprocessors, which are auxiliary processors that operate in tandem with the CPU to perform specific tasks, such as, but not limited to, mathematical calculations or encryption; Digital Signal Processors (DSPs), which are processors optimized for processing digital signals in real time, used in telecommunications and multimedia; Systems on Chips (SoCs), which are integrated chips that include, but are not limited to, CPU, GPU, DSP, and other components of the device in consideration; microcontrollers (MCUs), which are compact processors with integrated memory and peripherals used in embedded systems and IoT; Field-Programmable Gate Arrays (FPGAs), which are programmable processors that allow the user to configure their architecture to perform specialized tasks; Neural Processing Units (NPUs), which are specialized processors optimized for machine learning and artificial intelligence tasks; Vision Processing Units (VPUs), which are specialized microprocessors that are a type of AI accelerators configured to hardware accelerate the operation of machine vision algorithms.

[0133] The processor 200.3 may be produced using any technology known in the art, such as, but not limited to, CMOS technology, Silicon-on-Insulator (SOI) technology, Silicon-Germanium (SiGe) technology, Gallium Nitride (GaN) technology, graphene transistor based technology, FinFET technology, GAAFET technology, etc. The processor 200.3 may be multi-core and support parallel data processing, which increases the operating efficiency of the BS 200.

[0134] Readable medium 200.4 is the storage device that stores executable instructions for processor 200.3. These instructions include instructions for performing the communication method according to the first aspect of the present invention or according to any development of the first aspect of the present invention, as well as any other instructions for controlling data transmission, signal processing, network resource management and other functions. The readable medium 200.4 in the BS 200 may be one or more of the following media, but not limited to the types of media mentioned below: Read-Only Memory (ROM), including but not limited to Mask ROM, PROM, EPROM, EEPROM; Random Access Memory (RAM), including but not limited to DRAM, SDRAM, DDR SDRAM, MRAM, SRAM, PRAM, RRAM, FRAM, Nano-RAM, CBRAM nvSRAM; flash memory, including but not limited to NAND flash memory, NOR flash memory, USB flash memory; Solid-State Drives (SSDs), including but not limited to SATA SSD, NVMe SSD; optical discs, including but not limited to CD-ROM, DVD, Blu-ray; magnetic storage devices, including but not limited to HDD, magnetic tapes; memory cards, including but not limited to SD cards, microSD.

[0135] The readable medium 200.4 may be produced using any technology known in the art, such as, but not limited to, CMOS technology, Silicon-On-Insulator (SOI) technology, FinFET technology, 3D NAND technology, etc.

[0136] It should be understood that Fig. 8 does not show all components of the BS 200. In particular, in addition to the components shown, the BS 200 may comprise other software and / or hardware components, such as, but not limited to, a power supply; a frequency-time resource scheduler implemented in software, hardware, or software and hardware and included in the BS 200 or located outside the BS 200, but in communication with it; a cooling system; input-output interfaces; switches and interconnections; a modulator / demodulator; a multiplexer / demultiplexer; filters; power control circuits; an operating system (OS) and other software. The BS 200 may be referred to by other names, such as a Transmit / Receive Point (TRP).

[0137] Provided in the third aspect of the present invention is the computer readable medium storing executable instructions which, when executed by a device, cause the device to perform the communication method according to the first aspect of the present invention or according to any development of the first aspect of the present invention. The readable medium may correspond to the readable medium 200.4 described above, so its repeated description is omitted here. The instructions may be in any language and be presented in any form, provided that such language and form of instructions can be perceived by the processor 200.3 and other equipment of the BS 200 and the instructions can be executed to perform the communication method according to the first aspect of the present invention or according to any development of the first aspect of the present invention, or to implement any other necessary functionality.

[0138] Provided in the fifth aspect of the present invention is the UE 400 schematically shown in Fig. 9, which comprises operatively coupled a transceiving unit 400.1, an antenna 400.2, a processor 400.3, and a readable medium 400.4 storing processor executable instructions which, when executed by the processor, cause the UE to perform the communication method according to the fourth aspect of the present invention or according to any development of the fourth aspect of the present invention.

[0139] The UE 400 may be an electronic user device that connects to telecommunication networks to provide access to various services and functions. Thus, the UE 400 may be, but is not limited to, a smartphone, a tablet, a smart watch, smart glasses, a fitness tracker, an augmented reality (AR) and / or virtual reality (VR) headset, a laptop, a desktop computer, a mini PC, a smart TV, a streaming media device, a medical device, a payment processing device, equipment installed on a vehicle, including an infotainment system, an Internet of Things (IoT) device, a smart sensor, a monitoring device, etc. The UE 400 may be referred to in other ways, such as a user terminal, a terminal, a user device, a mobile device, etc.

[0140] The descriptions of possible implementations of the transceiving unit 200.1, antenna 200.2, processor 200.3, and readable medium 200.4 comprised in the BS 200 are essentially applicable, mutatis mutandis, respectively, as the descriptions of possible implementations of the transceiving unit 400.1, antenna 400.2, processor 400.3, and readable medium 400.4 comprised in the UE 400. Therefore, such descriptions are not repeated here.

[0141] Provided in the sixth aspect of the present invention is the computer readable medium storing executable instructions which, when executed by a device, cause the device to perform the communication method according to the fourth aspect of the present invention or according to any development of the fourth aspect of the present invention. The description of possible implementations of the readable medium 200.4 is essentially applicable, mutatis mutandis, as the description of the readable medium according to the sixth aspect of the present invention. Therefore, it is not described again here. The instructions may be in any language and be presented in any form, provided that such language and form of instructions can be perceived by the processor 400.3 and other components of the UE 400 and the instructions can be executed to perform the communication method according to the fourth aspect of the present invention or according to any development of the fourth aspect of the present invention, or to implement any other necessary functionality.

[0142] Fig. 10 illustrates the schematic representation of the communication system 500 according to seventh aspect of the present invention. The communication system 500 comprises one BS 200, which is installed to serve UEs 400 in three deployed cells 1, 2, 3. The BS may correspond to the BS 200 described in detail above with reference to Fig. 8, and each UE may correspond to the UE 400 described in detail above with reference to Fig. 9, so detailed descriptions of the BS 200 and the UE 400 are not given here again. The communication system 500 may simultaneously support several active radio access technologies (RATs) such as 4G LTE, 5G NR, 6G.

[0143] The specific details shown in Fig. 10 should not be considered as limitations of the present technology, since the system 500 may have a different architecture and be characterized / illustrated differently, for example, each cell of cell 1, cell 2, cell 3 may have its own BS 200, the number of UEs 400 in the cells may differ from that shown, cells 1, 2, 3 may represent one larger cell, the shape and space covered by the cells may differ from that shown, etc. The number of cells may be greater or less than 3.

[0144] Industrial Applicability

[0145] The present invention can be applied in 3GPP compliant communication networks with BS and UE that support xMIMO up to 256 digital ports / 4096 antenna elements. The proposed frequency band for using the disclosed invention is the upper part of the mid-frequency band (7-13 GHz). The technical solutions according to the present disclosure can be implemented with analog / digital single / multi-beam beamforming and TDD and / or FDD duplex modes. Other applications of the technology disclosed herein will be apparent to those of ordinary skill in the art upon review of this detailed description of the present application.

[0146] At least one aspect of the disclosed technical solution may be implemented by means of an AI model. The function associated with the AI can be performed by a read-only memory, random access memory, and processor(s) (CPU, GPU, NPU). The processor(s) controls the processing of input data in accordance with a predefined operating rule or an AI model stored in read-only memory and random access memory. The predefined operating rule or AI model is provided through training. Here, "provided through training" means that by applying a learning algorithm to a set of training data, a predefined operating rule or AI model with a desired characteristic is created. The training may be performed within the device itself that uses the AI model according to the embodiment (i.e., online), and / or may be implemented via a separate server / system (i.e., offline).

[0147] The AI model may be a decision tree-based algorithm or may consist of multiple layers of a neural network. Each layer has a plurality of weights and performs the operation of the layer through a calculation based on the result of the calculation in the previous layer and the application of a plurality of weights and other parameter values. Examples of decision tree based algorithms include a random forest, tree ensembles, etc., and examples of neural networks include, among others, Convolutional Neural Network (CNN), Deep Neural Network (DNN), Recurrent Neural Network (RNN), Restricted Boltzmann Machine (RBM), Deep Belief Network (DBN), Bi-directional Network, Bi-directional Recurrent Deep Neural Network (BRDNN), Generative Adversarial Network (GAN), Transformer-based Networks, Deep Q-Network, large language models etc. Some of the above architectures may additionally employ a self-attention mechanism.

[0148] A learning algorithm is a method for learning a predetermined target device or target function based on a corresponding set of training data that causes, enables, controls, or provides output data of the target device or target function. Examples of learning algorithms include, but not limited to, supervised learning, unsupervised learning, semi-supervised learning or reinforcement learning, and so on.

[0149] In the non-limiting example, AI model may be trained, which is applied at step S205 described above with reference to Fig. 1, to determine the value of one or more of FDCP, SDCP, TDCP based on frequency, time and / or spatial characteristics of received reference signals (e.g. single-port TRS, single-port CSI-RS, multi-port CSI-RS, etc.). When training such an AI model, various combinations of frequency, time and / or spatial characteristics of the received reference signals (e.g. single-port TRS, single-port CSI-RS, multi-port CSI-RS, etc.) can be used as training data in pairs with the corresponding reference values of one or more of FDCP, SDCP, TDCP. The reference values of one or more of FDCP, SDCP, TDCP may be predefined by the network operator or equipment manufacturer, or determined according to the equations given above. This AI-trained model can then be uploaded to the UE 400 and applied to implement step S205.

[0150] In another non-limiting example, the AI model for determining configuration parameters can be trained in a generally similar manner (but with its training data, such as pairs of one or more of the FDCP, SDCP, TDCP and / or other values that may be contained in the CSI report, and corresponding values of one or more reference configuration parameters) and uploaded (in the form of weights of the AI model obtained during training and executable instructions) into the memory of the BS 200 for its use in place of the threshold method given above as the implementation of step S110 described above with reference to Fig. 1.

[0151] One skilled in the art will appreciate that the various illustrative logical blocks (functional blocks or modules) and steps (operations) used in embodiments of the disclosed technical solution may be implemented by electronic hardware, computer software, or a combination thereof. Whether the functions are implemented with the use of hardware or software depends on particular applications and requirements to a design of an entire system. A person skilled in the art can use different methods to implement the described functions for each particular application, but it should not be considered that the implementation will go beyond the scope of the embodiments disclosed in the application.

[0152] It should also be noted that the order of steps of any disclosed method is not strict, because some one or more steps may be rearranged in the actual order of execution and / or combined with another one or more steps, and / or subdivided into a larger number of sub-steps.

[0153] Furthermore, the present invention should not be limited to the above notation form of any equation 1-6, since any equation 1-6 can be rewritten in a different form (for example, but without limitation, with other variables), but the calculation of the corresponding values according to such modified notion forms of equations 1-6 will provide the same values of the parameters as in the present invention. Thus, it is expected that on the basis of this detailed disclosure, a person of ordinary skill in the art will understand the entire concept and essence of the present invention, as claimed in the form of the invention, and this concept and essence of the present invention should not be reduced to the above forms of notion of said equations. In a certain sense, there exist or can be compiled by an ordinary specialist in this field of technology on the basis of this disclosure other (equivalent) notion forms of the above equations. It is intended that the claims of the present invention cover all such possible equivalent notion forms of said equations and equivalents of any other features by which the present invention is described in the present application.

[0154] Throughout this application, a reference to an element in the singular form does not preclude the presence of a plurality of such elements in the actual implementation of the invention, and, conversely, a reference to an element in the plural form does not exclude the presence of only one such element in the actual implementation of the invention. Any specific value or a range of values stated above should not be interpreted in a limiting sense, but rather such specific value or range of values should be considered to represent the midpoint of a specified larger range, up to approximately 50% or more% on either side of the specifically stated value or from the boundaries of the specifically specified range.

[0155] Although this disclosure has been shown and described with reference to specific embodiments and examples thereof, those skilled in the art will appreciate that various changes in form and detail may be made without departing from the spirit and scope of this disclosure as defined by the appended claims and their equivalents. In other words, the above detailed description is based on specific examples and possible implementations of the present invention, but it should not be interpreted so that only the explicitly disclosed implementations are feasible. It is intended that any modification or substitution that could be made to this disclosure by one of ordinary skill in the art without creative and / or technical contribution shall be within the scope of protection (with equivalents considered) provided by the following claims.

Claims

1.A method performed by a base station (BS) for controlling communication with a user equipment (UE), in which properties of a communication channel between the BS and the UE are taken into account, the method comprising:transmitting one or more reference signals, wherein the reference signal is the channel state information reference signal (CSI-RS);receiving, from the UE, in a channel state information report (CSI report) at least one spatial domain channel property (SDCP) value or at least one frequency domain channel property (FDCP) value, wherein the SDCP value represents spatial domain channel correlation corresponding to at least some CSI-RS antenna ports, and the FDCP value represents frequency domain channel correlation corresponding to at least some subcarriers of the CSI-RS antenna port;determining one or more values of one or more configuration parameters from signaling configuration parameters and CSI calculation configuration parameters based on the at least one SDCP value or the at least one FDCP value received from the UE; andtransmitting, to the UE, at least one value from the determined one or more values of the one or more configuration parameters.2.The method of claim 1, further comprising:applying at least one value of the one or more values of the one or more signaling configuration parameters to configure the downlink.3.The method of claim 1, wherein the at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, carry the CSI-RS or a tracking reference signal (TRS), andwherein the at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, are located in one or more physical resource blocks (PRBs).4.The method of claim 1, further comprising:receiving at least one time domain channel property (TDCP) value, wherein the TDCP value represents a time domain channel correlation corresponding to orthogonal frequency division multiplexing (OFDM) symbols in one or more OFDM slots, andwherein the determination of the one or more values of the one or more configuration parameters is carried out further based on said at least one TDCP value.5.A base station (BS) for controlling communication with a user equipment (UE), in which properties of a communication channel between the BS and the UE are taken into account, the BS comprising:a transceiver, andat least one processor configured to:transmit, via the transceiver, one or more reference signals, wherein the reference signal is the channel state information reference signal (CSI-RS),receive, from the UE, in a channel state information report (CSI report) at least one spatial domain channel property (SDCP) value or at least one frequency domain channel property (FDCP) value, wherein the SDCP value represents spatial domain channel correlation corresponding to at least some CSI-RS antenna ports, and the FDCP value represents frequency domain channel correlation corresponding to at least some subcarriers of the CSI-RS antenna port,determine one or more values of one or more configuration parameters from signaling configuration parameters and CSI calculation configuration parameters based on the at least one SDCP value or the at least one FDCP value received from the UE, andtransmit, to the UE via the transceiver, at least one value from the determined one or more values of the one or more configuration parameters.6.The BS of claim 5, wherein the at least one processor configured to:apply at least one value of the one or more values of the one or more signaling configuration parameters to configure the downlink.7.The BS of claim 5, wherein the at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, carry the CSI-RS or a tracking reference signal (TRS), andwherein the at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, are located in one or more physical resource blocks (PRBs).8.The BS of claim 5, wherein the at least one processor configured to:receive, via the transceiver, at least one time domain channel property (TDCP) value, wherein the TDCP value represents a time domain channel correlation corresponding to orthogonal frequency division multiplexing (OFDM) symbols in one or more OFDM slots, andwherein the determination of the one or more values of the one or more configuration parameters is carried out further based on said at least one TDCP value.9.A method performed by a user equipment (UE) of communication with a base station (BS), in which channel properties are taken into account, the method comprising:receiving one or more reference signals, wherein the reference signal is the channel state information reference signal (CSI-RS);calculating at least one spatial domain channel property (SDCP) value or at least one frequency domain channel property (FDCP) value, wherein the SDCP value represents spatial domain channel correlation corresponding to at least some CSI-RS antenna ports, and the FDCP value represents frequency domain channel correlation corresponding to at least some subcarriers of the CSI-RS antenna port;transmitting, to the BS, in a CSI report the calculated at least one SDCP value or at least one FDCP value; andreceiving, from the BS, at least one value of one or more values of, respectively, one or more configuration parameters from signaling configuration parameters and CSI calculation configuration parameters.10.The method of claim 9, further comprising:receiving from the BS a downlink transmission configured based on the one or more values of, respectively, one or more signaling configuration parameters determined based on the at least one SDCP value and / or the at least one FDCP value.11.The method of claim 9, further comprising:calculating at least one time domain channel property (TDCP) value, wherein the TDCP value represents a time domain channel correlation corresponding to orthogonal frequency division multiplexing (OFDM) symbols in one or more OFDM slots; andtransmitting, to the BS, the at least one TDCP value to enable at the BS the determination of the one or more values of the one or more configuration parameters from signaling configuration parameters and CSI calculation configuration parameters further based on the at least one TDCP value,wherein the at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, carry CSI-RS or a tracking reference signal (TRS), andwherein the at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, are located in one or more physical resource blocks (PRBs).12.A user equipment (UE) of communication with a base station (BS), in which channel properties are taken into account, the UE comprising:a transceiver, andat least one processor configured to:receive, via the transceiver, one or more reference signals, wherein the reference signal is the channel state information reference signal (CSI-RS);calculating at least one spatial domain channel property (SDCP) value and / or at least one frequency domain channel property (FDCP) value, wherein the SDCP value represents spatial domain channel correlation corresponding to at least some CSI-RS antenna ports, and the FDCP value represents frequency domain channel correlation corresponding to at least some subcarriers of the CSI-RS antenna port,transmit, to the BS via the transceiver, in a CSI report the calculated at least one SDCP value or at least one FDCP value; andreceive, from the BS via the transceiver, at least one value of one or more values of, respectively, one or more configuration parameters from signaling configuration parameters and CSI calculation configuration parameters.13.The UE of claim 12, wherein the at least one processor configured to:receiving from the BS a downlink transmission configured based on the one or more values of, respectively, one or more signaling configuration parameters determined based on the at least one SDCP value or the at least one FDCP value.14.The UE of claim 12, wherein the at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, carry CSI-RS or a tracking reference signal (TRS), andwherein the at least some subcarriers of the CSI-RS antenna port, which correspond to the frequency domain channel correlation, are located in one or more physical resource blocks (PRBs).15.The UE of claim 12, wherein the at least one processor configured to:calculate at least one time domain channel property (TDCP) value, wherein the TDCP value represents a time domain channel correlation corresponding to orthogonal frequency division multiplexing (OFDM) symbols in one or more OFDM slots, andtransmit, to the BS via the transceiver, the at least one TDCP value to enable at the BS the determination of the one or more values of the one or more configuration parameters from signaling configuration parameters and CSI calculation configuration parameters further based on the at least one TDCP value.

Images