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EP-4740315-A1 - APPARATUS AND METHOD FOR BEAMFORMING FOR DOWNLINK DATA TRANSMISSION IN WIRELESS COMMUNICATION SYSTEM

EP4740315A1EP 4740315 A1EP4740315 A1EP 4740315A1EP-4740315-A1

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method includes that: a base station sends configuration information comprising CSI configuration; the base station also transmits (e.g. periodically) CSI-RSs from all its CSI-RS antenna ports; a user device performs measurements with respect to received CSI-RS; upon reception, from the base station, of a CSI feedback indication; and the user device performs calculations to generate CSI based on the performed measurements and the received configuration.

Inventors

  • DAVYDOV, ALEXEI VLADIMIROVICH
  • MOROZOV, GREGORY VLADIMIROVICH
  • ESIUNIN, Denis Viktorovich
  • DIKAREV, Dmitry Sergeyevich
  • ERMOLAEV, Gregory Aleksandrovich
  • ESIUNIN, Maksim Viktorovich
  • PESTRETSOV, VLADIMIR ALEXANDROVICH

Assignees

  • Samsung Electronics Co., Ltd.

Dates

Publication Date
20260513
Application Date
20240528

Claims (15)

  1. A method performed by a user equipment (UE) supporting a beam forming in a wireless communication system, the method comprising: receiving, from a base station, configuration information on channel state information (CSI) including parameters of a code book and a parameter (NDFT) indicative of a maximum number of discrete Fourier transform (DFT) vectors with one signal polarization in a precoding matrix; receiving, from the base station, CSI reference signals (CSI-RSs); and based on the received CSI-RSs, transmitting, to the base station, CSI including at least one a rank indicator (RI) of a chosen number L of multiple input and multiple output (MIMO) layers, and a precoding matrix indicator (PMI).
  2. The method of claim 1, further comprising: choosing a number (L) of MIMO layers; in case that L ≤ N DFT , generating L precoding vectors by using L different DFT vectors, each being used with one signal polarization, in case that N DFT < L ≤ 2 N DFT , generating N DFT precoding vectors by using N DFT different DFT vectors, each being used with one signal polarization, and generating further N next precoding vectors, where N next = L - N DFT , by using N next DFT vectors from the N DFT DFT vectors, each of the N next DFT vectors being used with a signal polarization different from said one signal polarization with which said DFT vector has been already used in the precoding matrix, or in case that L > 2 N DFT , generating L precoding vectors by using N DFT = ceil ( L /2) different DFT vectors, wherein each of floor ( L /2) DFT vectors among the N DFT DFT vectors is used with two different signal polarizations to generate 2·floor ( L /2) precoding vectors, and, if mod ( L ,2)=1, a remaining DFT vector among the N DFT DFT vectors is used with one signal polarization to generate a respective precoding vector, wherein the parameters of the code book includes at least one a number ( N 1 ) of antenna ports of the base station along a first spatial dimension and a respective oversampling parameter ( O 1 ), and a number ( N 2 ) of antenna ports of the base station along a second spatial dimension and a respective oversampling parameter ( O 2 ), wherein a number of DFT vectors defined by the code book is equal to ( N 1 Х O 1 ) Х ( N 2 Х O 2 ), wherein different DFT vectors are orthogonal DFT vectors, wherein different signal polarizations are orthogonal signal polarizations, and wherein the configuration information is transmitted by using at least one data control information (DCI), medium access control (MAC), radio resource control (RRC) signaling.
  3. The method of claim 1, further comprising: determining L individual normalization parameters, wherein the individual normalization parameters are respectively individual for the L MIMO layers.
  4. The method of claim 3, wherein the determining individual normalization parameters comprises: determining an individual normalization parameter for each precoding vector of the precoding matrix depending on whether a same DFT vector is used with different signal polarizations both for a MIMO layer associated with precoding vector and for a MIMO layer associated with another precoding vector of the precoding matrix; and setting an individual normalization parameter for each precoding vector of the precoding matrix to 1, and wherein applying the normalization parameters further comprises: multiplying the precoding vectors of the precoding matrix by the respective determined individual normalization parameters.
  5. A method performed by a base station supporting a beam forming in a wireless communication system, the method comprising: generating configuration information on channel state information (CSI) including parameters of a code book and a parameter ( N DFT ) indicative of a maximum number of discrete Fourier transform (DFT) vectors with one signal polarization in a precoding matrix; transmitting, to a user equipment (UE), the configuration information on the CSI; transmitting, to the UE, CSI reference signals (CSI-RSs); and receiving, from the UE, CSI including at least one a rank indicator (RI) of a chosen number L of multiple input and multiple output (MIMO) layers, and a prcoding matrix indicator (PMI).
  6. The method of claim 5, further comprising: determining normalization parameters for the generated precoding matrix by using normalizing information, wherein the determined normalization parameters includes a common normalization parameter applied to the precoding matrix as a whole and individual normalization parameter respectively applied to individual precoding vectors or groups of precoding vectors of the precoding matrix; and applying the determined normalization parameters to the generated precoding matrix, wherein the configuration information further includes information for power normalizing the precoding matrix, and wherein L is chosen from a plurality of preset values and a maximum value of the L is 16.
  7. The method of claim 5, further comprising: calculating a respective common normalization parameter based on at least one a predefined EIRP restriction, an antenna gain, a transmission power, and value of L for each value of L among plurality of preset values, and including the calculated common normalization parameters into the normalizing information.
  8. The method of claim 6, wherein determining the normalization parameters comprises: selecting, among the calculated common normalization parameters, a common normalization parameter corresponding to said chosen number L of MIMO layers, for being applied to the generated precoding matrix, and wherein the applying the common normalization parameter comprises: multiplying the precoding matrix by a normalization multiplier which includes said common normalization parameter.
  9. A user equipment (UE) supporting a beam forming in a wireless communication system, the UE comprising: a transceiver; and a controller configured to: receive, from a base station, configuration information on channel state information (CSI) including parameters of a code book and a parameter (NDFT) indicative of a maximum number of discrete Fourier transform (DFT) vectors with one signal polarization in a precoding matrix, receive, from the base station, CSI reference signals (CSI-RSs); and based on the received CSI-RSs, transmit, to the base station, CSI including at least one a rank indicator (RI) of a chosen number L of multiple input and multiple output (MIMO) layers, and a precoding matrix indicator (PMI).
  10. The UE of claim 9, wherein the controller is further configured to: choose a number (L) of MIMO layers; in case that L ≤ N DFT , generate L precoding vectors by using L different DFT vectors, each being used with one signal polarization, in case that N DFT < L ≤ 2 N DFT , generate N DFT precoding vectors by using N DFT different DFT vectors, each being used with one signal polarization, and generating further N next precoding vectors, where N next = L - N DFT , by using N next DFT vectors from the N DFT DFT vectors, each of the N next DFT vectors being used with a signal polarization different from said one signal polarization with which said DFT vector has been already used in the precoding matrix, or in case that L > 2 N DFT , generate L precoding vectors by using N DFT = ceil ( L /2) different DFT vectors, wherein each of floor ( L /2) DFT vectors among the N DFT DFT vectors is used with two different signal polarizations to generate 2·floor ( L /2) precoding vectors, and, if mod ( L ,2)=1, a remaining DFT vector among the N DFT DFT vectors is used with one signal polarization to generate a respective precoding vector, wherein the parameters of the code book includes at least one a number ( N 1 ) of antenna ports of the base station along a first spatial dimension and a respective oversampling parameter ( O 1 ), and a number ( N 2 ) of antenna ports of the base station along a second spatial dimension and a respective oversampling parameter ( O 2 ), wherein a number of DFT vectors defined by the code book is equal to ( N 1 Х O 1 ) Х ( N 2 Х O 2 ), wherein different DFT vectors are orthogonal DFT vectors, wherein different signal polarizations are orthogonal signal polarizations, and wherein the configuration information is transmitted by using at least one data control information (DCI), medium access control (MAC), radio resource control (RRC) signaling.
  11. The UE of claim 10, wherein the controller is further configured to: determine L individual normalization parameters, wherein the individual normalization parameters are respectively individual for the L MIMO layers.
  12. The UE of claim 11, wherein the controller is further configured to: determine an individual normalization parameter for each precoding vector of the precoding matrix depending on whether a same DFT vector is used with different signal polarizations both for a MIMO layer associated with precoding vector and for a MIMO layer associated with another precoding vector of the precoding matrix, set an individual normalization parameter for each precoding vector of the precoding matrix to 1, and multiply the precoding vectors of the precoding matrix by the respective determined individual normalization parameters.
  13. A base station supporting a beam forming in a wireless communication system, the base station comprising: a transceiver; and a controller configured to: generate configuration information on channel state information (CSI) including parameters of a code book and a parameter (NDFT) indicative of a maximum number of discrete Fourier transform (DFT) vectors with one signal polarization in a precoding matrix, transmit, to a user equipment (UE), the configuration information on the CSI, transmit, to the UE, CSI reference signals (CSI-RSs), and receive, from the UE, CSI including at least one a rank indicator (RI) of a chosen number L of multiple input and multiple output (MIMO) layers, and a prcoding matrix indicator (PMI).
  14. The base station of claim 13, wherein the controller is further configured to: determine normalization parameters for the generated precoding matrix by using normalizing information, wherein the determined normalization parameters includes a common normalization parameter applied to the precoding matrix as a whole and individual normalization parameter respectively applied to individual precoding vectors or groups of precoding vectors of the precoding matrix, and apply the determined normalization parameters to the generated precoding matrix, wherein the configuration information further includes information for power normalizing the precoding matrix, and wherein L is chosen from a plurality of preset values and a maximum value of the L is 16.
  15. The base station of claim 13, wherein the controller is further configured to: calculate a respective common normalization parameter based on at least one a predefined EIRP restriction, an antenna gain, a transmission power, and value of L for each value of L among plurality of preset values, include the calculated common normalization parameters into the normalizing information, select, among the calculated common normalization parameters, a common normalization parameter corresponding to said chosen number L of MIMO layers, for being applied to the generated precoding matrix, and multiply the precoding matrix by a normalization multiplier which includes said common normalization parameter.

Description

APPARATUS AND METHOD FOR BEAMFORMING FOR DOWNLINK DATA TRANSMISSION IN WIRELESS COMMUNICATION SYSTEM The disclosure relates to wireless communications. More particularly, the disclosure relates to devices and methods for beamforming for downlink data transmission. 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. 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. 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. 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. 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. 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 RI