WO2024255825A1 - Rétroaction et compression de canal direct sur une dimension d'antenne rx - Google Patents

Rétroaction et compression de canal direct sur une dimension d'antenne rx Download PDF

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Publication number
WO2024255825A1
WO2024255825A1 PCT/CN2024/099143 CN2024099143W WO2024255825A1 WO 2024255825 A1 WO2024255825 A1 WO 2024255825A1 CN 2024099143 W CN2024099143 W CN 2024099143W WO 2024255825 A1 WO2024255825 A1 WO 2024255825A1
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Prior art keywords
matrix
coefficient matrix
basis
dft
receiver
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Ceased
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PCT/CN2024/099143
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English (en)
Inventor
Chin-Kuo Jao
Jiann-Ching Guey
Chia-Hao Yu
Tzu-Han Chou
Visanakarra Goraknath Guptha
Jinesh Parameshwaran Nair
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MediaTek Inc
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MediaTek Inc
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Publication date
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Priority to CN202480037728.3A priority Critical patent/CN121511560A/zh
Publication of WO2024255825A1 publication Critical patent/WO2024255825A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • H04B7/0478—Special codebook structures directed to feedback optimisation
    • H04B7/048—Special codebook structures directed to feedback optimisation using three or more PMIs

Definitions

  • This disclosure generally relates to mobility management for 5G or 6G communication system, and more particularly, to a method and device for reporting channel state information (CSI) for 5G or 6G communication system.
  • CSI channel state information
  • a User Equipment also called as a Mobile Station (MS)
  • MS Mobile Station
  • a mobile phone also known as a cellular phone or cell phone
  • PC Personal Computer
  • the wireless communication between the UE and the wireless communication network may be performed using various Radio Access Technologies (RATs) , such as Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, LTE-Advanced (LTE-A) technology, and New Radio (NR) technology etc.
  • RATs Radio Access Technologies
  • GSM Global System for Mobile communications
  • GPRS General Packet Radio Service
  • EDGE Enhanced Data rates for Global Evolution
  • WCDMA Wideband Code Division Multiple Access
  • CDMA-2000 Code Division Multiple Access 2000
  • TD-SCDMA Time Division-Synchronous Code Division Multiple Access
  • WiMAX Worldwide Interoperability for
  • GSM/GPRS/EDGE technology is also called 2G technology
  • WCDMA/CDMA-2000/TD-SCDMA technology is also called 3G technology
  • LTE/LTE-A/TD-LTE technology is also called 4G technology
  • NR technology is also called 5G technology.
  • the precoding matrix W is determined by UE feedback.
  • UE reports the Precoder Matrix Indication (PMI) as one of its Channel State Information (CSI) feedbacks, which are used by UE to inform the base station about the condition of the channel state.
  • PMI Precoder Matrix Indication
  • CSI Channel State Information
  • a method of reporting channel state information (CSI) by a user equipment (UE) comprises directly reporting a channel matrix of N T transmitter antennas and N R receiver antennas for subbands.
  • the method further comprises a Radio Resource Control (RRC) signal is configured to enable the UE to directly report the channel matrix of N T transmitter antennas and N R receiver antennas for subbands.
  • RRC Radio Resource Control
  • the channel matrix of N T transmitter antennas and N R receiver antennas for subbands can be decomposed as a Spatial Domain (SD) basis matrix W SD containing a set of SD basis vectors, a Frequency Domain (FD) basis matrix W FD containing a set of FD basis vectors, and a projection coefficient matrix ⁇ r associated to the SD basis matrix W SD and the FD basis matrix W FD .
  • SD Spatial Domain
  • FD Frequency Domain
  • the set of SD basis vectors is a set of orthogonal SD basis vectors or a set of non-orthogonal SD basis vectors.
  • the set of FD basis vectors is a set of orthogonal FD basis vectors or a set of non-orthogonal FD basis vectors.
  • a set of Discrete Fourier Transform (DFT) basis vectors with oversampling is used for the set of SD basis vectors.
  • DFT Discrete Fourier Transform
  • a set of Discrete Fourier Transform (DFT) basis vectors with oversampling is used for the set of FD basis vectors.
  • DFT Discrete Fourier Transform
  • the set of SD basis vectors is a set of SD basis vectors with reduced number of vectors.
  • the set of FD basis vectors is a set of FD basis vectors with reduced number of vectors.
  • the UE further reports a rotation phase indication.
  • the UE further reports a basis selection indication.
  • the UE selects non-zero coefficients (NZCs) based on a NZC selection ratio ( ⁇ 1 ) controlling the number of coefficients of the projection coefficient matrix ⁇ r to be reported.
  • NZCs non-zero coefficients
  • the NZC selection ratio ( ⁇ 1 ) is a value configured in a Radio Resource Control (RRC) signal.
  • RRC Radio Resource Control
  • the NZC selection ratio ( ⁇ 1 ) is a value reported by the UE.
  • the number of NZCs of the projection coefficient matrix ⁇ r to be reported is equal for each receiver antenna.
  • a sum of the number of NZCs of each projection coefficient matrix ⁇ r to be reported is limited to a pre-determined value.
  • the UE reports a bitmap of NZC locations for each projection coefficient matrix ⁇ r .
  • the bitmap of NZC locations is a receiver antenna specific bitmap or a receiver antenna common bitmap.
  • the UE reshapes the projection coefficient matrix ⁇ r as a coefficient matrix ⁇ across a receiver antenna domain.
  • the UE applies a Discrete Fourier Transform (DFT) compression or a singular value decomposition (SVD) compression on the coefficient matrix ⁇ before selecting non-zero coefficients (NZCs) based on a NZC selection ratio ( ⁇ 1 ) .
  • DFT Discrete Fourier Transform
  • SVD singular value decomposition
  • the UE applies a Discrete Fourier Transform (DFT) compression or a singular value decomposition (SVD) compression on the coefficient matrix ⁇ after selecting non-zero coefficients (NZCs) based on a NZC selection ratio ( ⁇ 1 ) .
  • DFT Discrete Fourier Transform
  • SVD singular value decomposition
  • the UE applies the DFT compression on each row of the coefficient matrix ⁇ and selects non-zero coefficients (NZCs) based on a receiver-dimensional compression ratio ( ⁇ 2 ) controlling the number of coefficients of the coefficient matrix ⁇ to be reported.
  • NZCs non-zero coefficients
  • the receiver-dimensional compression ratio ( ⁇ 2 ) is a value configured in a Radio Resource Control (RRC) signal.
  • RRC Radio Resource Control
  • the receiver-dimensional compression ratio ( ⁇ 2 ) is a value reported by the UE.
  • the DFT matrix with oversampling can be in a normal DFT form, a polarization-common form, or a polarization-specific form depending on the receiver antennas.
  • the UE trims singular values in the ⁇ and W H as and to retain dominated coefficients for the coefficient matrix ⁇ .
  • the UE trims the W H into can be constrained by limiting the frequency domain elements in a contiguous window of length-N.
  • FIG. 1 illustrates a N r ⁇ N t channel matrix H [n] .
  • FIG. 2 illustrates a reshaped channel matrix F r based on the N r ⁇ N t channel matrix H [n] .
  • FIG. 3 illustrates the locations of NZCs for each receiver antenna.
  • FIG. 4 illustrates taking DFT to each row of the coefficient matrix ⁇ before NZC selection.
  • FIG. 5 illustrates taking DFT to each row of the coefficient matrix ⁇ after NZC selection.
  • FIG. 6 illustrates performing SVD compression on the coefficient matrix ⁇ before NZC selection.
  • FIG. 7 illustrates performing SVD compression on the coefficient matrix ⁇ after NZC selection.
  • a first embodiment of the present disclosure is a method of reporting channel state information (CSI) by a user equipment (UE) .
  • the method comprises the UE is allowed to directly report Direct Channel Feedback (DCF) information instead of Precoder Matrix Indication (PMI) as its CSI feedback to a base station (BS) , such as a gNodeB (gNB) .
  • DCF Direct Channel Feedback
  • PMI Precoder Matrix Indication
  • BS base station
  • gNB gNodeB
  • RRC Radio Resource Control
  • MIMO Multiple Input Multiple Output
  • F r can be further decomposed as where W SD is a Spatial Domain (SD) basis matrix containing a set of SD basis vectors, W FD is a Frequency Domain (FD) basis matrix containing a set of FD basis vectors, and ⁇ r is a projection coefficient matrix associated to the SD basis matrix W SD and the FD basis matrix W FD .
  • W SD Spatial Domain
  • FD Frequency Domain
  • ⁇ r is a projection coefficient matrix associated to the SD basis matrix W SD and the FD basis matrix W FD .
  • the SD basis matrix W SD may contain a set of orthogonal SD basis vectors in one example. Specifically, there are N t orthogonal Discrete Fourier Transform (DFT) basis vectors in In addition, the orthogonal DFT basis vectors with oversampling factor (O 1 , O 2 ) can be considered to achieve a finer horizontal and vertical beam resolution.
  • DFT Discrete Fourier Transform
  • the SD basis matrix W SD may contain a set of non-orthogonal SD basis vectors in another example.
  • the non-orthogonal DFT basis vectors with oversampling factor (O 1 , O 2 ) can also be considered to achieve a finer horizontal and vertical beam resolution.
  • the N t ⁇ N t O 1 O 2 SD basis matrix can be expressed as
  • N t 2N 1 N 2 , is a N 1 N 2 O 1 O 2 -length DFT vector with k-th oversampling phase
  • N 1 and N 2 are the numbers of antenna ports of the same polarization direction in horizontal and vertical domains
  • O 1 and O 2 are the oversampling factors in respective dimensions.
  • the FD basis matrix W FD may contain a set of orthogonal FD basis vectors in one example. Specifically, there are N 3 orthogonal DFT basis vectors in In addition, the orthogonal DFT basis vectors with oversampling factor (O 3 ) can be considered to ensure a proper phase rotation for frequency domain.
  • the FD basis matrix can be expressed as where is a N 3 -length DFT vector with k-th oversampling phase, and N 3 is the number of subbands.
  • the FD basis matrix W FD may contain a set of non-orthogonal FD basis vectors in another example.
  • the non-orthogonal DFT basis vectors with oversampling factor (O 3 ) can be considered to ensure a proper phase rotation for frequency domain.
  • There are N 3 O 3 non-orthogonal DFT basis vectors in The FD basis matrix can be expressed as
  • the UE In order to mitigate the feedback overhead, it is also considered for the UE to report the SD basis matrix W SD with reduced number of vectors and the FD basis matrix W FD with reduced number of vectors in accordance with the first embodiment of the present disclosure. Specifically, the UE selects proper vectors from the original full space of the SD basis matrix W SD containing aforementioned orthogonal SD basis vectors or non-orthogonal SD basis vectors and the FD basis matrix W FD containing aforementioned orthogonal FD basis vectors or non-orthogonal FD basis vectors.
  • the SD basis matrix W SD contains a set of orthogonal SD basis vectors
  • UE needs to report a proper rotation phase and thus needs bits for reporting as a rotation phase indication.
  • UE selects L beams (or vectors) from N 1 N 2 beams for each polarization, and then the SD basis matrix after selection can be expressed as and thus needs bits for reporting as a basis selection indication.
  • L N 1 N 2
  • the SD basis matrix W SD contains a set of non-orthogonal SD basis vectors
  • UE selects L beams (or vectors) from N 1 N 2 O 1 O 2 beams for each polarization, and then the SD basis matrix W SD after selection can be expressed as and thus needs bits for reporting as a basis selection indication.
  • L N 1 N 2 O 1 O 2
  • no bit is required for reporting the SD basis matrix W SD contains a set of non-orthogonal SD basis vectors.
  • the FD basis matrix W FD contains a set of orthogonal FD basis vectors
  • UE needs to report a proper rotation phase and thus needs bits for reporting as a rotation phase indication.
  • UE selects M taps (or vectors) from N 3 taps, and then the FD basis matrix after selection can be expressed as and thus needs bits for reporting as a basis selection indication.
  • M N 3
  • the FD basis matrix W FD contains a set of non-orthogonal FD basis vectors
  • UE selects M taps (or vectors) from N 3 O 3 taps, and then the FD basis matrix W FD after selection can be expressed as and thus needs bits for reporting as a basis selection indication.
  • M N 3 O 3
  • no bit is required for reporting the FD basis matrix W FD contains a set of non-orthogonal FD basis vectors.
  • the UE can derive the projection coefficient matrix ⁇ r to be reported by
  • NZCs non-zero coefficients
  • the NZC selection ratio ( ⁇ 1 ) is a value configured in a Radio Resource Control (RRC) signal.
  • RRC Radio Resource Control
  • the NZC selection ratio ( ⁇ 1 ) is a value reported by the UE. For example, assume 2LM is equal to 20 and the NZC selection ratio ( ⁇ 1 ) is 0.5 provided by the RRC signal, and then the number of NZCs to be reported is less than or equal to 10.
  • the number of NZCs of the projection coefficient matrix ⁇ r to be reported is equal for each receiver antenna, i.e., P r ⁇ 1 2LM.
  • a sum of the number of NZCs of each projection coefficient matrix ⁇ r to be reported is limited to a pre-determined value P, i.e.,
  • NZCs i.e. a bitmap
  • the locations of NZCs, i.e. a bitmap, for each receiver antenna is required to be reported as shown in FIG. 3.
  • the locations of NZCs on a bitmap for each projection coefficient matrix ⁇ r could be receiver antenna specific, which means the bitmap for each receiver antenna is specific.
  • the UE is required to report N r bitmaps and thus 2LMN r bits are needed for reporting, where N r is the number of the receiver antennas.
  • the locations of NZCs on a bitmap for each projection coefficient matrix ⁇ r could be receiver antenna common, which means the bitmap for each receiver antenna is the same.
  • the UE is required to only one bitmap, and thus 2LM bits are needed for reporting.
  • the UE is required to report not only the locations of NZCs (bitmap) but also values of NZCs in accordance with the first embodiment of the present disclosure.
  • NZCs are complex numbers represented by magnitude and phase angle. 3 bits are needed for reporting magnitude of a complex number and 4 bits are needed for reporting phase angle of a complex number, and thus (3+4) ⁇ 1 2LM ⁇ N r bits are required for reporting for NZCs.
  • the projection coefficient matrix ⁇ r could be further compressed across a receiver antenna domain.
  • the projection coefficient matrix ⁇ r could be compressed by different approaches.
  • the receiver antennas are spaced uniformly, the DFT basis can be used to compress the projection coefficient matrix ⁇ r across receiver dimension.
  • the receiver antennas are irregularly spaced but cross-polarized, the projection coefficient matrix ⁇ r can be compressed by a singular value decomposition (SVD) approach.
  • SVD singular value decomposition
  • the DFT compression can be performed before NZC selection based on the aforementioned NZC selection ratio ( ⁇ 1 ) .
  • the DFT compression is performed by the following steps.
  • Select the P′ ⁇ 2 ⁇ 2LMN r NZCs from ⁇ ′ for reporting, where ⁇ 2 is a receiver-dimensional compression ratio controlling the number of coefficients of the coefficient matrix ⁇ to be reported (STEP 3) .
  • the receiver-dimensional compression ratio ( ⁇ 2 ) is a value configured in a Radio Resource Control (RRC) signal.
  • RRC Radio Resource Control
  • the DFT compression can be performed after NZC selection based on the aforementioned NZC selection ratio ( ⁇ 1 ) .
  • the DFT compression is performed by the following steps.
  • Select the P′ ⁇ 2 ⁇ P r N r NZCs from ⁇ ′ for reporting, where ⁇ 2 is a receiver-dimensional compression ratio controlling the number of coefficients of the coefficient matrix ⁇ to be reported (STEP 3) .
  • the receiver-dimensional compression ratio ( ⁇ 2 ) is a value configured in a Radio Resource Control (RRC) signal.
  • RRC Radio Resource Control
  • the aforementioned DFT matrix could be a DFT matrix with oversampling factor O r , and could further be in a normal DFT form, a polarization-common form, or a polarization-specific form depending on the receiver antennas.
  • DFT matrix W r could be where W r1 is DFT matrix.
  • DFT matrix W r could be
  • the SVD compression can be performed before NZC selection based on the aforementioned NZC selection ratio ( ⁇ 1 ) as shown in FIG. 6. Specifically, the SVD compression is performed by the following steps.
  • the UE utilizes the SVD approach to decompose the coefficient matrix ⁇ as follows.
  • the UE trims the coefficient matrix ⁇ to retain dominated coefficients for the coefficient matrix ⁇ as follows.
  • ⁇ N r (STEP 3) .
  • the singular values of ⁇ i , i> ⁇ is trimmed if ⁇ ⁇ is smaller than ⁇ 0 by a pre-defined dB, such as 10 dB.
  • the SVD compression can be performed after NZC selection based on the aforementioned NZC selection ratio ( ⁇ 1 ) as shown in FIG. 7. Specifically, the SVD compression is performed by the following steps.
  • the UE utilizes the SVD approach to decompose the coefficient matrix ⁇ as follows.
  • the UE trims the coefficient matrix ⁇ to retain dominated coefficients for the coefficient matrix ⁇ as follows.
  • ⁇ N r (STEP 3) .
  • the singular values of ⁇ i , i> ⁇ is trimmed if ⁇ ⁇ is smaller than ⁇ 0 by a pre-defined dB, such as 10 dB.
  • the precoder can be determined by ⁇ H ⁇ , which is not a function of In other words, the UE only reports and and the feedback quantity can only be which is the set of the linear combination coefficients of
  • a device such as a UE, may include a processor, memory in electronic communication with the processor, and instructions stored in the memory.
  • the instructions are used to perform the methods in accordance with the embodiments above.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radio Transmission System (AREA)

Abstract

Un procédé de rapport d'informations d'état de canal (CSI) par un équipement utilisateur (UE) est décrit. Le procédé consiste à rapporter directement une matrice de canal de NT antennes de transmission et NR antennes de réception pour des sous-bandes.
PCT/CN2024/099143 2023-06-16 2024-06-14 Rétroaction et compression de canal direct sur une dimension d'antenne rx Ceased WO2024255825A1 (fr)

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CN202480037728.3A CN121511560A (zh) 2023-06-16 2024-06-14 直接信道反馈和接收天线维度上的压缩

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IN202321040991 2023-06-16

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180262253A1 (en) * 2017-03-09 2018-09-13 Samsung Electronics Co., Ltd. Method and apparatus for covariance matrix feedback in advanced wireless communication systems
EP3734853A1 (fr) * 2019-05-02 2020-11-04 Fraunhofer Gesellschaft zur Förderung der angewandten Forschung e.V. Procédé et appareil d'amélioration d'indication de sous-ensemble de base pour un reporting csi basé sur deux livres de codes
US20220038159A1 (en) * 2018-12-11 2022-02-03 Qualcomm Incorporated Compressed csi feedback for non-contiguous frequency resources

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180262253A1 (en) * 2017-03-09 2018-09-13 Samsung Electronics Co., Ltd. Method and apparatus for covariance matrix feedback in advanced wireless communication systems
US20220038159A1 (en) * 2018-12-11 2022-02-03 Qualcomm Incorporated Compressed csi feedback for non-contiguous frequency resources
EP3734853A1 (fr) * 2019-05-02 2020-11-04 Fraunhofer Gesellschaft zur Förderung der angewandten Forschung e.V. Procédé et appareil d'amélioration d'indication de sous-ensemble de base pour un reporting csi basé sur deux livres de codes
CN114128161A (zh) * 2019-05-02 2022-03-01 弗劳恩霍夫应用研究促进协会 在无线通信系统中用于csi报告的方法和设备

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