# US 12,224,828 B2 · Method of type II CSI reporting for multiple spatial layers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,224,828 B2 - Document ID: US12224828B2 - Status: Granted - Kind: B2 - Application number: 17/430,642 - Filed: 2020-02-06 - Published: 2022-06-09 - Granted: 2025-02-11 - Earliest claimed: 2019-02-14 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Victor Sergeev; Alexei Davydov; Bishwarup Mondal; Dmitry Dikarev - Web page: https://patentgrep.com/patent/US12224828B2 ## CPC - H04B 7/0469: {taking special antenna structures, e.g. cross polarized antennas into account} - H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]} - H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection} - H04B 7/0632: {Channel quality parameters, e.g. channel quality indicator [CQI]} - H04B 7/0634: {Antenna weights or vector/matrix coefficients} - H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection} - H04B: TRANSMISSION ## Abstract Some embodiments of this disclosure include apparatuses and methods for reporting channel state information (CSI) for multiple spatial layers. The apparatuses and methods can include at least: determining, by a user equipment (UE), a precoding matrix indicator (PMI) for a set of precoding matrixes, wherein the PMI is determined based on a combination of digital Fourier transformation (DFT) spatial domain (SD) vectors, or based on DFT-based frequency domain (FD) compression; and transmitting, by the UE, the PMI to a next-generation NodeB (gNB). ## Claims ### Claim 1 A method of reporting channel state information (CSI) for multiple spatial layers comprising: determining, by a user equipment (UE), a precoding matrix indicator (PMI) for a set of precoding matrixes, wherein the PMI is determined based on a combination of mutually orthogonal digital Fourier transformation (DFT) spatial domain (SD) vectors with DFT-based frequency-domain (FD) compression, wherein the mutually orthogonal DFT SD vectors are selected as N subsets of a plurality of oversampled DFT SD vectors and a total number of elements of the N subsets is fixed, where N is a positive number greater than 1; and transmitting, by the UE, the PMI to a base station. ### Claim 2 (depends on 1) The method of claim 1, wherein transmitting the PMI includes transmitting in a channel state information (CSI) report. ### Claim 3 (depends on 2) The method of claim 2, further comprising generating the CSI report to include a channel quality indicator (CQI) or a rank indicator (RI). ### Claim 4 (depends on 1) The method of claim 1, wherein transmitting the PMI includes transmitting via a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). ### Claim 5 (depends on 1) The method of claim 1, further comprising generating a codebook to include the set of precoding matrixes. ### Claim 6 (depends on 5) The method of claim 5, further comprising defining the codebook for a set of ranks. ### Claim 7 (depends on 6) The method of claim 6, further comprising constructing, by the UE, a column of a precoding matrix in the codebook based on a linear combination of spatial domain (SD) vectors. ### Claim 8 A non-transitory computer readable medium having instructions stored thereon that, when executed by one or more processors of a user equipment (UE), cause the UE to perform operations comprising: determining a precoding matrix indicator (PMI) for a set of precoding matrixes, wherein the PMI is determined based on a combination of mutually orthogonal digital Fourier transformation (DFT) spatial domain (SD) vectors with DFT-based frequency-domain (FD) compression, wherein the mutually orthogonal DFT SD vectors are selected as N subsets of a plurality of oversampled DFT SD vectors and a total number of elements of the N subsets is fixed, where N is a positive number greater than 1; and transmitting the PMI to a base station. ### Claim 9 (depends on 8) The non-transitory computer readable medium of claim 8, wherein the transmitting the PMI includes transmitting in a channel state information (CSI) report. ### Claim 10 (depends on 9) The non-transitory computer readable medium of claim 9, wherein the operations further comprise generating the CSI report to include a channel quality indicator (CQI) or a rank indicator (RI). ### Claim 11 (depends on 8) The non-transitory computer readable medium of claim 8, wherein the transmitting the PMI includes transmitting via a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). ### Claim 12 (depends on 8) The non-transitory computer readable medium of claim 8, wherein the operations further comprise generating a codebook to include the set of precoding matrixes. ### Claim 13 (depends on 12) The non-transitory computer readable medium of claim 12, wherein the operations further comprise defining the codebook for a set of ranks. ### Claim 14 (depends on 13) The non-transitory computer readable medium of claim 13, wherein the operations further comprise constructing a column of a precoding matrix in the codebook based on a linear combination of spatial domain (SD) vectors. ### Claim 15 A user equipment (UE) comprising: a processor configured to determine a precoding matrix indicator (PMI) for a set of precoding matrixes, wherein the PMI is determined based on a combination of mutually orthogonal digital Fourier transformation (DFT) spatial domain (SD) vectors with DFT-based frequency-domain (FD) compression, wherein the mutually orthogonal DFT SD vectors are selected as N subsets of a plurality of oversampled DFT SD vectors and a total number of elements of the N subsets is fixed, where N is a positive number greater than 1; and a radio frequency integrated circuit, coupled to the processor, configured to transmit the PMI to a base station. ### Claim 16 (depends on 15) The system of claim 15, wherein the PMI is transmitted to the base station in a channel state information (CSI) report. ### Claim 17 (depends on 16) The system of claim 16, wherein the CSI report further includes a channel quality indicator (CQI) or a rank indicator (RI). ### Claim 18 (depends on 15) The system of claim 15, wherein the PMI is transmitted to the base station via a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). ### Claim 19 (depends on 15) The system of claim 15, wherein the set of precoding matrixes are included in a codebook. ### Claim 20 (depends on 19) The system of claim 19, wherein the codebook is defined for a set of ranks.