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EP-4740312-A1 - BEAM COMBINING CODEBOOK FOR LOW PEAK-TO-AVERAGE POWER RATIO-BASED WAVEFORM

EP4740312A1EP 4740312 A1EP4740312 A1EP 4740312A1EP-4740312-A1

Abstract

This disclosure provides systems, devices, apparatus, and methods, including computer programs encoded on storage media, for a beam combing codebook for a low PAPR-based waveform. A UE (102) receives (304), from a network entity (104), a configuration for a codebook including a precoder for a beam. The precoder is associated with a plurality of antenna ports, where each antenna port of the plurality of antenna ports is mapped to no more than one layer. The UE (102) receives (308), from the network entity (104), a CSI-RS on a CMR configured for the beam and transmits (310), to the network entity (104), a CSI report based on the configuration and the CSI-RS.

Inventors

  • FWU, JONG-KAE
  • ZHANG, YUSHU

Assignees

  • Google LLC

Dates

Publication Date
20260513
Application Date
20230803

Claims (16)

  1. A method of wireless communication at user equipment (UE) (102) , comprising: receiving (304) , from a network entity (104) , a configuration for a codebook including a precoder for a beam, the precoder being associated with a plurality of antenna ports, each antenna port of the plurality of antenna ports being mapped to no more than one layer; receiving (308) , from the network entity (104) , a channel state information-reference signal (CSI-RS) on a channel measurement resource (CMR) configured for the beam; and transmitting (310) , to the network entity (104) , a channel state information (CSI) report based on the configuration and the CSI-RS.
  2. The method of claim 1, wherein the CSI report indicates at least one of: a rank indicator (RI) , a beam index for the codebook, a beam combining matrix for the codebook, or a channel quality indicator (CQI) .
  3. The method of any of claims 1-2, wherein the codebook includes a plurality of precoders for a target waveform selected from a plurality of target waveforms.
  4. The method of any of claims 1-3, wherein the configuration for the codebook indicates at least one of: a type of the codebook, whether the codebook supports the target waveform, a number of reported beams, a first number of horizontal antenna ports, a second number of vertical antenna ports, a first oversampling factor for horizontal beams, a second oversampling factor for vertical beams, or whether a selected beam is common to a plurality of layers.
  5. The method of any of claims 1-4, wherein the beam index for the codebook is based on a first indicator (402) for an oversampled beam index and a second indicator (404) for a non-oversampled beam index.
  6. The method of claim 5, wherein the first indicator (502a) for the oversampled beam index is for a first stage of oversampling, and wherein the oversampled beam index is associated with a third indicator (502b) for a second stage of oversampling.
  7. The method of any of claims 1-6, wherein the transmitting (310) the CSI report, further comprises: reporting (610, 620, 710, 720) a channel quality indicator (CQI) based on at least one of a wideband beam combining matrix or a subband beam combining matrix.
  8. The method of claim 7, wherein the subband beam combining matrix corresponds to a compressed subband beam combining matrix.
  9. The method of any of claims 1-8, wherein the configuration for the codebook indicates a frequency domain measurement hypothesis (1120, 1220) for the beam combining matrix.
  10. The method of any of claims 1-9, further comprising: transmitting (302) , to the network entity (104) , an indication of a UE capability for the codebook including the precoder with each antenna port mapped to the no more than one layer.
  11. The method of any of claims 1-10, further comprising: receiving (306) , from the network entity (104) , a triggering indication for the CSI report.
  12. A method of wireless communication at a network entity (104) , comprising: transmitting (304) , to a user equipment (UE) (102) , a configuration for a codebook including a precoder for a beam, the precoder being associated with a plurality of antenna ports, each antenna port of the plurality of antenna ports being mapped to no more than one layer; transmitting (308) , to the UE (102) , a channel state information-reference signal (CSI-RS) on a channel measurement resource (CMR) configured for the beam; and receiving (310) , from the UE (102) , a channel state information (CSI) report based on the configuration and the CSI-RS.
  13. The method of claim 12, wherein the CSI report indicates at least one of: a rank indicator (RI) , a beam index for the codebook, a beam combining matrix for the codebook, or a channel quality indicator (CQI) .
  14. The method of any of claims 12-13, wherein the codebook includes a plurality of precoders for a target waveform selected from a plurality of target waveforms.
  15. The method of any of claims 12-14, wherein the configuration for the codebook indicates at least one of: a type of the codebook, whether the codebook supports the target waveform, a number of reported beams, a first number of horizontal antenna ports, a second number of vertical antenna ports, a first oversampling factor for horizontal beams, a second oversampling factor for vertical beams, or whether a selected beam is common to a plurality of layers.
  16. An apparatus for wireless communication comprising a transceiver, a memory, and a processor coupled to the memory and the transceiver, the apparatus being configured to implement a method as in any of claims 1-15.

Description

BEAM COMBINING CODEBOOK FOR LOW PEAK-TO-AVERAGE POWER RATIO-BASED WAVEFORM TECHNICAL FIELD The present disclosure relates generally to wireless communication, and more particularly, to a beam combining codebook for a low peak-to-average power ratio (PAPR) -based waveform. BACKGROUND The Third Generation Partnership Project (3GPP) specifies a radio interface referred to as fifth generation (5G) new radio (NR) (5G NR) . An architecture for a 5G NR wireless communication system includes a 5G core (5GC) network, a 5G radio access network (5G-RAN) , a user equipment (UE) , etc. The 5G NR architecture seeks to provide increased data rates, decreased latency, and/or increased capacity compared to prior generation cellular communication systems. Wireless communication systems, in general, provide various telecommunication services (e.g., telephony, video, data, messaging, broadcasts, etc. ) based on multiple-access technologies, such as orthogonal frequency division multiple access (OFDMA) technologies, that support communication with multiple UEs. Improvements in mobile broadband continue the progression of such wireless communication technologies. For example, while Type 2 channel state information (CSI) codebooks may be configured for cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) waveforms, such codebooks may not be suitable for single carrier waveforms. BRIEF SUMMARY The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects. This summary neither identifies key or critical elements of all aspects nor delineates the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later. A network entity may use channel state information (CSI) to select a digital precoder for a user equipment (UE) in a multiple-input multiple-output (MIMO) system. For  example, the network entity can configure a CSI report using radio resource control (RRC) signaling, where a channel state information-reference signal (CSI-RS) is used as a channel measurement resource (CMR) for the UE to measure a downlink channel. While the UE may use a Type 2 CSI codebook in association with measuring and reporting the CSI, such codebooks may be configured for cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) waveforms. An increased power-amplifier efficiency combined with a low peak-to-average power ratio (PAPR) signal can allow the network entity to transmit a downlink signal with a higher transmission power. Thus, to reduce the PAPR while providing the increased power-amplifier efficiency, the network entity may use a discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-s-OFDM) waveform, single-carrier frequency division multiple access (SC-FDMA) waveform, or other single-carrier waveform for a physical downlink shared channel (PDSCH) transmission, as opposed to transmission of the CP-OFDM waveform. For DFT-s-OFDM, the network entity applies a transform precoder (e.g., discrete Fourier transform (DFT) ) on modulated symbols followed by subsequent application of the digital precoder for transmission of the downlink signal. Accordingly, the network entity and the UE may implement a beam combining codebook for low PAPR waveforms, where selection of the digital precoder is based on individual antenna ports being mapped to no more than one layer (e.g., to maintain single-carrier properties) . However, current beam combining codebooks include precoders with a same antenna port mapped to multiple layers, which may result in producing high PAPR signals. Therefore, such precoders may not be suitable for low PAPR-based waveforms. Additionally, the network entity may also use the CSI feedback to reduce instances of precoder mismatch between the PDSCH and the CSI-RS, where a common precoder is applied for a scheduled PDSCH but a first bandwidth for the scheduled PDSCH is different than a second bandwidth for the CSI-RS. Thus, the CSI feedback may improve the downlink performance for low PAPR-based PDSCH transmissions. According to some aspects, the UE receives, from the network entity, a configuration for a codebook including a precoder for a beam. The precoder is associated with a plurality of antenna ports, where each antenna port of the plurality of antenna ports is mapped to no more than one layer. The UE receives, from the network entity, a CSI-RS on a CMR  configured for the beam and transmits, to the network entity, a CSI report based on the configuration and the CSI-RS. According to some aspects, the network entity transmits, to the UE, the configuration for the codebook including the precoder for the beam. The precoder is associated with the plurality of antenna ports, where each antenna port is mapped to the no