WO2021007695A1 - Système et procédé de rapport d'état de canal et d'informations sur une fréquence doppler - Google Patents

Système et procédé de rapport d'état de canal et d'informations sur une fréquence doppler Download PDF

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Publication number
WO2021007695A1
WO2021007695A1 PCT/CN2019/095750 CN2019095750W WO2021007695A1 WO 2021007695 A1 WO2021007695 A1 WO 2021007695A1 CN 2019095750 W CN2019095750 W CN 2019095750W WO 2021007695 A1 WO2021007695 A1 WO 2021007695A1
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WIPO (PCT)
Prior art keywords
csi
time
rss
domain
domain bases
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PCT/CN2019/095750
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English (en)
Inventor
Chenxi HAO
Yu Zhang
Liangming WU
Qiaoyu Li
Chao Wei
Hao Xu
Wanshi Chen
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Qualcomm Incorporated
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Priority to PCT/CN2019/095750 priority Critical patent/WO2021007695A1/fr
Priority to PCT/CN2019/115073 priority patent/WO2021008007A1/fr
Priority to PCT/CN2020/101290 priority patent/WO2021008450A1/fr
Publication of WO2021007695A1 publication Critical patent/WO2021007695A1/fr

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    • 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
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/063—Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
    • 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
    • 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
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/0628—Diversity capabilities

Definitions

  • the present disclosure relates generally to communications systems, and more particularly, to a user equipment that is to report channel state and Doppler frequency information to a base station.
  • Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts.
  • Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single-carrier frequency division multiple access
  • TD-SCDMA time division synchronous code division multiple access
  • 5G New Radio is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements.
  • 3GPP Third Generation Partnership Project
  • 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra reliable low latency communications (URLLC) .
  • eMBB enhanced mobile broadband
  • mMTC massive machine type communications
  • URLLC ultra reliable low latency communications
  • 5G NR may be based on the 4G Long Term Evolution (LTE) standard.
  • LTE Long Term Evolution
  • channel conditions may vary based on a number of factors, including distance between transmitter and receiver, interfering signals, blockages/obstructions, and the like.
  • a base station may determine the channel conditions when transmitting data to a user equipment (UE) . To do so, the base station may transmit reference signals (RSs) , which the UE may measure in order to determine channel-state information (CSI) .
  • RSs reference signals
  • CSI channel-state information
  • the UE may transmit a report to the base station that indicates the CSI for a channel on which the UE is to receive data from the base station. Based on the reported CSI, the base station may determine a transmission configuration for channel conditions of the channel on which the base station 102/180 is to transmit data to the UE (that is, the channel for which the UE reports CSI) .
  • the channel conditions of the channel upon which the CSI is based (and on which the base station is to transmit data to the UE) may include information associated with the quality of the channel or other information associated with the channel that may influence how the base station configures a set of parameters for transmitting to the UE on the channel.
  • the base station may transmit data to the UE on the channel based on the determined transmission configuration. However, the reported CSI may become outdated, for example, due to the processing time at the UE or base station, changing channel conditions, and so forth.
  • repeatedly transmitting CSI reports from the UE to the base station may increase the overheads of over-the-air signaling, computational resources, and time. Accordingly, a need exists for techniques and approaches for reducing the overhead associated with CSI reporting, while also determining a transmission configuration for channel conditions of a channel (e.g., fading on the channel) , for example, so that the base station may configure a set of parameters for transmission to the UE on the channel at a future time.
  • a transmission configuration for channel conditions of a channel e.g., fading on the channel
  • a method, a computer-readable medium, and an apparatus are provided.
  • the apparatus may be a UE.
  • the apparatus may be configured to receive a first set of CSI-RSs from a base station.
  • the apparatus may determine a Doppler frequency based on a carrier on which communication with the base station is configured.
  • the apparatus may transmit at least one CSI report to the base station based on the first set of CSI-RSs.
  • the apparatus may transmit information indicating the Doppler frequency to the base station.
  • the other apparatus may be a base station.
  • the other apparatus may transmit a first set of CSI-RSs.
  • the other apparatus may receive, from a UE, at least one CSI report associated with the first set of CSI-RSs.
  • the other apparatus may receive, from the UE, information indicating a Doppler frequency associated with a carrier on which communication with the UE is configured.
  • the other apparatus may determine a transmission configuration associated with data transmission to the UE on the carrier based on the at least one CSI report and based on the Doppler frequency.
  • the other apparatus may transmit data to the UE based on the transmission configuration
  • the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims.
  • the following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.
  • Figure 1 is a diagram illustrating an example of a wireless communications system and an access network.
  • Figures 2A, 2B, 2C, and 2D are diagrams illustrating examples of a first 5G/NR frame, DL channels within a 5G/NR subframe, a second 5G/NR frame, and UL channels within a 5G/NR subframe, respectively.
  • Figure 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network.
  • UE user equipment
  • Figure 4 is a call flow diagram illustrating communication in a wireless communication system.
  • Figures 5A and 5B are a flowchart of a method of wireless communication by a UE.
  • Figure 6 is a flowchart of a method of wireless communication by a base station.
  • processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure.
  • processors in the processing system may execute software.
  • Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.
  • the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium.
  • Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer.
  • such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.
  • RAM random-access memory
  • ROM read-only memory
  • EEPROM electrically erasable programmable ROM
  • optical disk storage magnetic disk storage
  • magnetic disk storage other magnetic storage devices
  • combinations of the aforementioned types of computer-readable media or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.
  • FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100.
  • the wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and another core network 190 (e.g., a 5G Core (5GC) ) .
  • the base stations 102 may include macrocells (high power cellular base station) or small cells (low power cellular base station) .
  • the macrocells include base stations.
  • the small cells include femtocells, picocells, and microcells.
  • the base stations 102 configured for 4G Long Term Evolution (LTE) may interface with the EPC 160 through backhaul links 132 (e.g., S1 interface) .
  • the base stations 102 configured for 5G NR may interface with core network 190 through backhaul links 184.
  • LTE Long Term Evolution
  • UMTS Universal Mobile Telecommunications System
  • 5G NR Next Generation RAN
  • the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages.
  • NAS non-access stratum
  • RAN radio access network
  • MBMS multimedia broadcast multicast service
  • RIM RAN information management
  • the base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or core network 190) with each other over backhaul links 134 (e.g., X2 interface) .
  • the backhaul links 134 may be wired or wireless.
  • the base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102' may have a coverage area 110' that overlaps the coverage area 110 of one or more macro base stations 102.
  • a network that includes both small cell and macrocells may be known as a heterogeneous network.
  • a heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) .
  • eNBs Home Evolved Node Bs
  • HeNBs Home Evolved Node Bs
  • CSG closed subscriber group
  • the communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104.
  • the communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, or transmit diversity.
  • MIMO multiple-input and multiple-output
  • the communication links may be through one or more carriers.
  • the base stations 102 /UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc.
  • the component carriers may include a primary component carrier and one or more secondary component carriers.
  • a primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .
  • D2D communication link 158 may use the DL/UL WWAN spectrum.
  • the D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) .
  • sidelink channels such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) .
  • sidelink channels such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) .
  • D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia,
  • the wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum.
  • AP Wi-Fi access point
  • STAs Wi-Fi stations
  • communication links 154 in a 5 GHz unlicensed frequency spectrum.
  • the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.
  • CCA clear channel assessment
  • the small cell 102′ may operate in a licensed or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to or increase capacity of the access network.
  • a base station 102 may include an eNB, gNodeB (gNB) , or another type of base station.
  • Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, or near mmW frequencies in communication with the UE 104.
  • mmW millimeter wave
  • mmW millimeter wave
  • mmW millimeter wave
  • mmW millimeter wave
  • the gNB 180 may be referred to as an mmW base station.
  • Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters.
  • Radio waves in the band may be referred to as a millimeter wave.
  • Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters.
  • the super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave.
  • Communications using the mmW /near mmW radio frequency band (e.g., 3 GHz –300 GHz) has extremely high path loss and a short range.
  • the mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range.
  • the base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 182'.
  • the UE 104 may receive the beamformed signal from the base station 180 in one or more receive directions 182".
  • the UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions.
  • the base station 180 may receive the beamformed signal from the UE 104 in one or more receive directions.
  • the base station 180 /UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 180 /UE 104.
  • the transmit and receive directions for the base station 180 may or may not be the same.
  • the transmit and receive directions for the UE 104 may or may not be the same.
  • the EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172.
  • MME Mobility Management Entity
  • MBMS Multimedia Broadcast Multicast Service
  • BM-SC Broadcast Multicast Service Center
  • PDN Packet Data Network
  • the MME 162 may be in communication with a Home Subscriber Server (HSS) 174.
  • HSS Home Subscriber Server
  • the MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160.
  • the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172.
  • IP Internet protocol
  • the PDN Gateway 172 provides UE IP address allocation as well as other functions.
  • the PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176.
  • the IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, or other IP services.
  • the BM-SC 170 may provide functions for MBMS user service provisioning and delivery.
  • the BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions.
  • PLMN public land mobile network
  • the MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.
  • MMSFN Multicast Broadcast Single Frequency Network
  • the core network 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195.
  • the AMF 192 may be in communication with a Unified Data Management (UDM) 196.
  • the AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190.
  • the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195.
  • the UPF 195 provides UE IP address allocation as well as other functions.
  • the UPF 195 is connected to the IP Services 197.
  • the IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, or other IP services.
  • IMS IP Multimedia Subsystem
  • the base station may also be referred to as a gNB, Node B, evolved Node B (eNB) , an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology.
  • the base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104.
  • Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device.
  • SIP session initiation protocol
  • PDA personal digital assistant
  • the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) .
  • the UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.
  • NR 5G New Radio
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • CDMA Code Division Multiple Access
  • GSM Global System for Mobile communications
  • the UE 104 and the base station 102/180 may be configured for communication on a communication link 120, such as a downlink channel of a configured carrier.
  • a communication link 120 such as a downlink channel of a configured carrier.
  • the UE 104 and the base station 102/180 may cooperate in order to determine a transmission configuration for channel conditions of the channel on which the base station 102/180 is to transmit data to the UE 104.
  • the base station 102/180 may configure a set of parameters for downlink transmission to the UE 104 based on the determined transmission configuration for the channel conditions of the channel.
  • the set of parameters configurable by the base station 102/180 for transmission to the UE 104 on the channel may be associated with a modulation and coding scheme (MCS) , precoding (e.g., for a precoding matrix) , spatial processing, a transmission layer, a transmission mode, and the like.
  • MCS modulation and coding scheme
  • precoding e.g., for a precoding matrix
  • spatial processing e.g., for a precoding matrix
  • the base station 102/180 may transmit reference signals (RSs) to the UE 104. Based on the RSs, the UE 104 may determine channel-state information (CSI) associated with the channel conditions on the communication link between the UE 104 and the base station 102/180. However, the CSI reports transmitted by the UE 104 may become outdated or increase the overheads on the UE 104 or the base station 102/180.
  • RSs reference signals
  • CSI channel-state information
  • the UE 104 may be configured to determine a Doppler frequency, which may facilitate the determination of a transmission configuration associated with the channel conditions of the channel on which the base station 102/180 may transmit data to the UE 104.
  • the Doppler frequency may be a maximum Doppler frequency associated with fading on at least one channel of a carrier on the communication link between the UE 104 and the base station 102/180.
  • the UE 104 may be configured to compress at least two CSI in the time domain, and the UE 104 may be configured to predict CSI corresponding to future time instances preceded in time by the RSs upon which the compressed CSI are based, which may reduce the overhead associated with CSI reporting.
  • the UE 104 may be configured to transmit, to the base station 102/180, one or more of the Doppler frequency, the time-domain compressed CSI, or the time-domain predicted CSI (198) .
  • the base station 102/180 may be configured to receive the one or more of the Doppler frequency, the time-domain compressed CSI, or the time-domain predicted CSI. Based on the received one or more of the Doppler frequency, the time-domain compressed CSI, or the time-domain predicted CSI, the base station 102/180 may determine the transmission configuration associated with the channel conditions of the channel on which the base station 102/180 is to transmit data to the UE 104. For example, the base station 102/180 may expand the time-domain compressed CSI and, if received from the UE 104, expand the time-domain predicted CSI.
  • the base station 102/180 may configure a set of transmission parameters associated with the channel (that is, the channel on which the base station 102/180 transmits the RSs for CSI reporting by the UE 104) . Subsequently, the base station 102/180 may transmit data to the UE 104 based on the determined transmission configuration for the channel associated with the CSI reporting by the UE 104 (199) .
  • Figure 2A is a diagram 200 illustrating an example of a first subframe within a 5G/NR frame structure.
  • Figure 2B is a diagram 230 illustrating an example of DL channels within a 5G/NR subframe.
  • Figure 2C is a diagram 250 illustrating an example of a second subframe within a 5G/NR frame structure.
  • Figure 2D is a diagram 280 illustrating an example of UL channels within a 5G/NR subframe.
  • the 5G/NR frame structure may be FDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for either DL or UL, or may be TDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for both DL and UL.
  • the 5G/NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL) , where D is DL, U is UL, and X is flexible for use between DL/UL, and subframe 3 being configured with slot format 34 (with mostly UL) .
  • slot formats 0, 1 are all DL, UL, respectively.
  • Other slot formats 2-61 include a mix of DL, UL, and flexible symbols.
  • UEs are configured with the slot format (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI) .
  • DCI DL control information
  • RRC radio resource control
  • SFI received slot format indicator
  • a frame (10 ms) may be divided into 10 equally sized subframes (1 ms) .
  • Each subframe may include one or more time slots.
  • Subframes may also include mini-slots, which may include 7, 4, or 2 symbols.
  • Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols.
  • the symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols.
  • the symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission) .
  • the number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies ⁇ 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology ⁇ , there are 14 symbols/slot and 2 ⁇ slots/subframe.
  • the subcarrier spacing and symbol length/duration are a function of the numerology.
  • the subcarrier spacing may be equal to 2 ⁇ *15 kHz, where ⁇ is the numerology 0 to 5.
  • ⁇ is the numerology 0 to 5.
  • the symbol length/duration is inversely related to the subcarrier spacing.
  • the subcarrier spacing is 15 kHz and symbol duration is approximately 66.7 ⁇ s.
  • a resource grid may be used to represent the frame structure.
  • Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends 12 consecutive subcarriers.
  • RB resource block
  • PRBs physical RBs
  • the resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.
  • the RS may include demodulation RS (DM-RS) (indicated as R x for one particular configuration, where 100x is the port number, but other DM-RS configurations are possible) and channel state information reference signals (CSI- RS) for channel estimation at the UE.
  • DM-RS demodulation RS
  • CSI- RS channel state information reference signals
  • the RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and phase tracking RS (PT-RS) .
  • BRS beam measurement RS
  • BRRS beam refinement RS
  • PT-RS phase tracking RS
  • FIG. 2B illustrates an example of various DL channels within a subframe of a frame.
  • the physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including nine RE groups (REGs) , each REG including four consecutive REs in an OFDM symbol.
  • a primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe/symbol timing and a physical layer identity.
  • a secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing.
  • the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DM-RS.
  • the physical broadcast channel (PBCH) which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block.
  • the MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) .
  • the physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.
  • SIBs system information blocks
  • some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station.
  • the UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH) .
  • the PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH.
  • the PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used.
  • the UE may transmit sounding reference signals (SRS) .
  • the SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.
  • FIG. 2D illustrates an example of various UL channels within a subframe of a frame.
  • the PUCCH may be located as indicated in one configuration.
  • the PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback.
  • UCI uplink control information
  • the PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , or UCI.
  • BSR buffer status report
  • PHR power headroom report
  • FIG. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network.
  • IP packets from the EPC 160 may be provided to a controller/processor 375.
  • the controller/processor 375 implements layer 3 and layer 2 functionality.
  • Layer 3 includes a radio resource control (RRC) layer
  • layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer.
  • RRC radio resource control
  • SDAP service data adaptation protocol
  • PDCP packet data convergence protocol
  • RLC radio link control
  • MAC medium access control
  • the controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDU
  • the transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions.
  • Layer 1 which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing.
  • the TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) .
  • BPSK binary phase-shift keying
  • QPSK quadrature phase-shift keying
  • M-PSK M-phase-shift keying
  • M-QAM M-quadrature amplitude modulation
  • the coded and modulated symbols may then be split into parallel streams.
  • Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream.
  • IFFT Inverse Fast Fourier Transform
  • the OFDM stream is spatially precoded to produce multiple spatial streams.
  • Channel estimates from a channel estimator 374 may be used to determine the MCS, as well as for spatial processing.
  • the channel estimate may be derived from a reference signal or channel condition feedback transmitted by the UE 350.
  • Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX.
  • Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.
  • each receiver 354RX receives a signal through its respective antenna 352.
  • Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356.
  • the TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions.
  • the RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream.
  • the RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) .
  • FFT Fast Fourier Transform
  • the frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal.
  • the symbols on each subcarrier, and the reference signal are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358.
  • the soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel.
  • the data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.
  • the controller/processor 359 can be associated with a memory 360 that stores program codes and data.
  • the memory 360 may be referred to as a computer-readable medium.
  • the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160.
  • the controller/processor 359 is also responsible for error detection using an ACK or NACK protocol to support HARQ operations.
  • the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.
  • RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting
  • PDCP layer functionality associated with
  • Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate MCSs, and to facilitate spatial processing.
  • the spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.
  • the UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350.
  • Each receiver 318RX receives a signal through its respective antenna 320.
  • Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.
  • the controller/processor 375 can be associated with a memory 376 that stores program codes and data.
  • the memory 376 may be referred to as a computer-readable medium.
  • the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller/processor 375 may be provided to the EPC 160.
  • the controller/processor 375 is also responsible for error detection using an ACK or NACK protocol to support HARQ operations.
  • At least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with (198) of Figure 1.
  • At least one of the TX processor 316, the RX processor 370, and the controller/processor 375 may be configured to perform aspects in connection with (199) of Figure 1.
  • a base station may determine a transmission configuration for channel conditions when transmitting data to a UE on a channel having the channel conditions.
  • the base station may transmit RSs, which the UE may measure in order to determine CSI.
  • the UE may transmit a report to the base station that indicates the CSI. Based on the reported CSI, the base station may determine a transmission configuration for channel conditions of a channel and, accordingly, may transmit data to the UE on the channel based on the determined transmission configuration.
  • the reported CSI may become outdated, for example, due to the processing time at the UE or base station, changing channel conditions, and so forth.
  • While one approach to preventing CSI from becoming stale may be to increase the amount or frequency of RSs (e.g., CSI-RSs) transmitted by the base station and commensurately increase the amount or frequency of CSI reports transmitted by the UE based on the RSs, such an approach may increase the overheads of over-the-air signaling and processing load.
  • the overhead of processing load may increase on both the base station and the UE because the uplink payload of CSI reports may increase the computational load on the UE to generate a greater number of CSI reports or to include a greater amount of information in each CSI report.
  • the computational load on the base station may increase because the base station would then have to decode and process a greater number of CSI reports or a larger payload in each CSI report.
  • Figures 4 through 6 may illustrate various techniques and approaches for determination of a transmission configuration for channel conditions of a channel (e.g., fading on the channel) on which the base station may transmit data to the UE at a future time, while also reducing the overhead associated with CSI reporting.
  • the UE may determine a Doppler frequency associated with fading, which may facilitate the determination of the transmission configuration for the channel conditions of the channel, and the UE may compress a set of CSI reports in the time domain, which may reduce the overhead associated with CSI reporting.
  • a call flow diagram illustrates wireless communications 400 between a base station 402 and a UE 404.
  • the UE 404 may be embodied in the UE 104 or the UE 350
  • the base station 402 may be embodied in the base station 102/180 or the base station 310.
  • the UE 404 may operate on a cell provided by the base station 402. While operating thereon, the UE 404 may synchronize with the base station 402 and a communication link between the two may be established.
  • the communication link may include a set of carriers (e.g., for carrier aggregation) .
  • the UE 404 may be configured at least for downlink communication on at least one of the set of carriers, which may be referred to as a configured carrier c.
  • the configured carrier c may include a center frequency f c .
  • the base station 402 may first determine a transmission configuration for channel conditions of a channel on the configured carrier c.
  • the base station 402 may use the determined transmission configuration, which may be based on a set of CSI reports received from the UE 404, in order to configure one or more of an MCS, precoding, spatial processing, transmission layer, transmission mode, and so forth.
  • the base station 402 may transmit a first set of RSs 420.
  • Each of the first set of RSs 420 may be a CSI-RS.
  • the base station 402 may transmit CSI-RS #0 422a, a CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • the UE 404 may receive each of the first set of RSs 420, and may determine CSI based on each of the first set of RSs 420.
  • the UE 404 may determine respective CSI corresponding to each of CSI-RS #0 422a, a CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • the UE 404 may determine at least one of CQI, PMI, an SS/PBCH resource block indicator, a layer indicator, a rank indicator, or a L1-reference signal received power (RSRP) based on a corresponding one of CSI-RS #0 422a, a CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • RSRP L1-reference signal received power
  • the UE 404 may transmit, to the base station 402, multiple CSI reports 432, and each of the multiple CSI reports 432 may be associated with the CSI of each of the CSI-RS #0 422a, a CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • the UE 404 may transmit one of the CSI reports 432 to the base station 402 based on CSI-RS #0 422a, the UE 404 may transmit another of the CSI reports 432 to the base station 402 based on CSI-RS #1 422b, and so forth, through each of the first set of RSs 420 until the UE 404 transmits one of the CSI reports 432 to the base station based on the most recent CSI-RS #N-1 422c.
  • the UE 404 may transmit the CSI reports 432 periodically, aperiodically, or semi-persistently.
  • the base station 402 may transmit information to the UE 404 that configures the UE 404 for one of the periodic CSI reporting, the aperiodic CSI reporting, or the semi-persistent CSI reporting.
  • the UE 404 may transmit each of the CSI reports 432 according to a time period, which may be configured for the UE 404 by the base station 402 (e.g., via RRC signaling) .
  • the UE 404 may determine CSI based on each CSI-RS #0 422a, a CSI-RS #1 422b, ..., CSI-RS #N-1 422c received during the time period, and the UE 404 may transmit a respective one of the CSI reports 432 for each of the CSI-RS #0 422a, a CSI-RS #1 422b, ..., CSI-RS #N-1 422c received by the UE 404 during the time period.
  • the UE 404 may transmit each of the CSI reports 432 in response to a message requesting CSI received from the base station 402. For example, the UE 404 may determine a duration (e.g., a number of slots) , which may be indicated by the message requesting CSI received from the base station 402. Over the determined duration, the UE 404 may receive each of the first set of RSs 420 from the base station 402, and the UE 404 may determine CSI based on each of the first set of RSs 420. The UE 404 may then transmit a respective one of the CSI reports 432 to the base station 402 based on the message requesting CSI received from the base station 402 and each of the first set of RSs 420 received over the duration.
  • a duration e.g., a number of slots
  • the UE 404 may first transmit each of the CSI reports 432 in response to a message requesting CSI received from the base station 402 (e.g., similarly to aperiodic CSI reporting) . Following this first cycle in which the UE 404 transmits the CSI reports 432 responsive to the message requesting CSI, however, the UE 404 may follow a periodic schedule for CSI reporting.
  • the base station 402 may receive the CSI reports 432 based on each of the first set of RSs 420. Subsequently, the base station 402 may determine 436 the transmission configuration for the channel conditions of the channel on the configured carrier c, and may then transmit data 438 to the UE 404 based on the determined transmission configuration.
  • the CSI reports 432 may incur both time and computational overheads and, consequently, the transmission configuration for the channel conditions may become outdated before the base station 402 is able to transmit data to the UE 404 based on the CSI reports 432. Therefore, the base station 402 or the UE 404 may be configured to determine at least a portion of the channel conditions (e.g., predict fading) for a future time based on previous channel conditions (e.g., observed fading) .
  • the channel conditions e.g., predict fading
  • the base station 402 or the UE 404 may be configured to predict fading on the configured carrier c by modeling the fading process as a deterministic process.
  • Equation 1 illustrates an exemplary aspect of the deterministic fading model:
  • u k [n] may be a predetermined sequence, which may be orthogonal to u j [n]
  • ⁇ k may be a linear combination coefficient.
  • the linear combination coefficients ( ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ) may be determined based on current or previous observations of fading on the configured carrier c and, therefore, may provide a satisfactory fit for the deterministic fading model h [0] , h [1] , ..., h [N′-1] .
  • the deterministic fading model with the linear combination coefficients determined based on current or previous observations of fading may satisfactorily predict fading on the configured carrier c.
  • the deterministic fading model according to Equation 1 may be associated with basis expansion, for example, in order to derive results (e.g., linear combination coefficients) that may be germane to the transmission configuration for channel conditions of a channel on which the base station 402 is to transmit data to the UE 404.
  • a basis may be determined for use with Equation 1.
  • This basis may be a time-domain basis.
  • the time-domain basis may be a Slepian basis, which may be applicable to the deterministic fading model at least in part because fading is band-limited; however, the time-domain basis may be different in other aspects (e.g., a fractional discrete Fourier transform (DFT) basis may be used) .
  • DFT fractional discrete Fourier transform
  • the fading process may be found within a subspace spanned by the time-domain (e.g., Slepian) basis, which may a low-rank subspace.
  • the time-domain e.g., Slepian
  • the time-domain basis may be determined based on a time interval and a frequency interval.
  • the time interval may be a sampling rate; for example, the sampling rate may be a slot duration or a symbol duration when the base station 402 and the UE 404 communicate in the time domain according to slot or symbol timing structures (see, e.g., Figure 2A and Figure 2C, supra) .
  • the frequency interval may be a range of a Doppler spectrum [-f Dmax , +f Dmax ] because the fading process is band-limited.
  • the range of the Doppler spectrum [-f Dmax , +f Dmax ] may be the maximum Doppler shift in hertz (Hz) for a distance the UE 404 may travel over a time interval (e.g., over a slot duration or over a symbol duration) .
  • the time-domain basis may be an eigenvector such that N-point time-domain (e.g., Slepian) bases are eigenvectors of a matrix (c ij ) N ⁇ N .
  • the matrix (c ij ) N ⁇ N of which the N-point time-domain bases may be eigenvectors, may be given by Equation 2.
  • v Dmax may be determined.
  • the UE 404 may perform measurements based on RSs.
  • the base station 402 may transmit RSs, which may be received by the UE 404.
  • the base station 402 may transmit a second set of RSs 424.
  • the base station 402 may transmit RS 426a, RS 426b, ..., RS 426c.
  • each of the second set of RSs 424 may be a tracking reference signal.
  • each of the second set of RSs 424 may be a CSI-RS.
  • the second set of RSs 424 may be the first set of RSs 420.
  • the UE 404 may receive each of the first set of RSs 420 and the second set of RSs 424. Based on the second set of RSs 424, the UE 404 may determine a speed v of the UE 404 (e.g., the speed v of the UE 404 as the UE 404 moves within the cell provided by the base station 402) . For example, the UE 404 may determine the time between two RSs 426a, 426b and may determine the distance traveled by the UE 404 during the time between the two RSs 426a, 426b. The UE 404 may derive the speed v of the UE 404 as the quotient of the determined distance divided by the time between the two RSs 426a, 426b.
  • a speed v of the UE 404 e.g., the speed v of the UE 404 as the UE 404 moves within the cell provided by the base station 402 .
  • the UE 404 may determine the time between two
  • the UE 404 may determine the speed v in kilometers (km) per second (s) (km/s) .
  • the UE 404 may determine 428 the v Dmax (also referred to as a “Doppler frequency” ) based on the speed v of the UE 404, as shown in Equation 3.
  • T s may be the time interval.
  • T s may be the duration of a slot or the duration of a symbol.
  • v Dmax may be based on a unit associated with a time-domain resource.
  • T s may be configured by the base station 402.
  • the base station 402 may determine the time interval T s , and the base station 402 may transmit information indicating the determined time interval T s to the UE 404.
  • T s may be preconfigured in the UE 404.
  • T s may be defined in at least one technical specification or standard promulgated by a standards organization, such as the 3 rd Generation Partnership Project (3GPP) .
  • 3GPP 3 rd Generation Partnership Project
  • the time interval T s may be indicated in the at least one technical specification or standard, such as by indicating a fixed value for T s or by indicating a set of rules or formulas to be followed or evaluated for determining or calculating a value of T s (e.g., the set of rules or formulas may include a set of variables and, accordingly, the base station 402 or the UE 404 may determine a corresponding value or other parameter for each variable of the set in order to evaluate the set of rules or formulas) .
  • a product is obtained that may be normalized with respect to the time domain by multiplying by T s .
  • the UE 404 may compute v Dmax , which may be between 0 and 1, based on the normalization with respect to the time domain.
  • the v Dmax value may be the maximum Doppler frequency associated with fading on at least one channel of the configured carrier c. Because v Dmax is a Doppler frequency, v Dmax may indicate how quickly channel conditions are changing on the configured carrier c (e.g., as affected by the speed of the UE 404) . A relatively higher value of v Dmax may indicate that channel conditions are changing relatively quickly on the configured carrier c, whereas a relatively lower value of v Dmax may indicate that channel conditions are relatively stable on the configured carrier c. For example, v Dmax being approximately 0 may indicate that channel conditions are stable or nearly unchanged.
  • the UE 404 may be able to calculate the time-domain bases (e.g., according to Equation 2, supra) based on the calculated v Dmax , the base station 402 may be unable to observe the speed v of the UE 404, and therefore may be unable to calculate v Dmax for the time-domain bases. Therefore, the UE 404 may transmit information indicating v Dmax 434 to the base station 402.
  • the UE 404 may quantize the value of v Dmax and transmit the quantized value of v Dmax to the base station 402. For example, the UE 404 may select, from a list of predetermined values, one predetermined value that most closely approximates v Dmax . The UE 404 may then include the quantized value (e.g., selected predetermined value) in the information indicating v Dmax 434 transmitted to the base station 402.
  • the quantized value e.g., selected predetermined value
  • the UE 404 may determine one level from a set of levels (e.g., “low, ” “medium, ” and “high” ) based on v Dmax . For example, the UE 404 may compare v Dmax to at least one threshold, and the UE 404 may select a corresponding level from the set of levels based on the comparison of v Dmax to the at least one threshold. The UE 404 may then include the level corresponding to v Dmax in the information indicating v Dmax 434 transmitted to the base station 402.
  • a set of levels e.g., “low, ” “medium, ” and “high”
  • the UE 404 may transmit the information indicating v Dmax 434 to the base station 402 separately from the one or more CSI reports 432. For example, the UE 404 may transmit the one or more CSI reports 432 to the base station 402 and, subsequently, the UE 404 may transmit the information indicating v Dmax 434 to the base station 402.
  • the UE 404 may include the information indicating v Dmax 434 in at least one of the one or more CSI reports 432.
  • the UE 404 may include the information indicating v Dmax 434 in each of the one or more CSI reports 432.
  • the UE 404 may include the information indicating v Dmax 434 in one of the one or more CSI reports 432, such as in a most recent one of the one or more CSI reports 432.
  • the information indicating v Dmax 434 may be included in any, in all, or in none of the one or more CSI reports 432.
  • v Dmax may facilitate the computation of a set of time-domain bases (e.g., according to Equation 2) associated with predicting fading on the configured carrier c (e.g., as modeled by the deterministic fading model according to Equation 1) .
  • the base station 402 may determine 436 a transmission configuration for channel conditions of a channel associated with the configured carrier c in order to transmit data to the UE 404.
  • the base station 402 may predict CSI based on the information indicating v Dmax 434 and, further, based on received CSI reports that may include outdated or stale CSI (e.g., CSI for one or more slots preceding the slot in which the base station 402 is to transmit data to the UE 404) .
  • the base station 402 may predict fading on a configured carrier c channel that carries downlink data to the UE 404 based on the information indicating v Dmax 434. Further, the base station 402 may determine 436 the transmission configuration for the channel conditions of the channel on the configured carrier c based on the one or more CSI reports 432 (e.g., for configuring an MCS, precoding, spatial processing, transmission layer, transmission mode, etc. ) . Accordingly, the base station 402 may use both the one or more CSI reports 432 and the received information indicating v Dmax 434 to determine 436 the transmission configuration. Subsequently, the base station 402 may transmit data 438 to the UE 404 based on the determination 436 of the transmission configuration for the channel conditions of the channel.
  • the UE 404 may be configured to reduce computational or signaling overheads experienced by the base station 402 by generating a set of time-domain bases and using the set of time-domain bases for time-domain compression to reduce the amount or frequency of CSI reports transmitted by the UE 404 to the base station 402.
  • the UE 404 may be configured to determine 430 one or more sets of time-domain bases and, further, to compress CSI respectively corresponding to each of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c within a single CSI report 432.
  • the UE 404 may determine CSI for each of the first set of RSs 420. That is, the UE 404 may determine CSI respectively corresponding to each of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c. However, rather than transmit each CSI report for the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c, the UE 404 may transmit a single CSI report 432 to the base station 402.
  • the UE 404 may use a first set of time-domain bases for time-domain compression of each of the CSI respectively corresponding to the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • the UE 404 may determine 430 the time-domain bases, for example, based on one or more rules defined in at least one technical specification or standard promulgated by a standards organization (e.g., a 3GPP technical specification) or according to another approach.
  • the first set of time-domain bases may be implicitly or explicitly indicated in the at least one technical specification or standard, such as by enumerating the first set of time-domain bases or by indicating a set of rules or formulas to be followed or evaluated for determining or calculating the first set of time-domain bases (e.g., the set of rules or formulas may include a set of variables and, accordingly, the base station 402 or the UE 404 may determine a corresponding value or other parameter for each variable of the set in order to evaluate the set of rules or formulas) .
  • the UE 404 may generate a first set of time-domain bases based on at least one of v Dmax or each time instance of each of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • Each of the first set of time-domain bases may be a Slepian basis, a fractional DFT basis, or another basis suitable for a band-limited deterministic model.
  • the UE 404 may determine the number of the first set of time-domain bases to generate, which may be denoted D.
  • D the number of the first set of time-domain bases may be given by where ⁇ is a scalar.
  • the UE 404 may determine the number D of the first set of time-domain bases to generate based on v Dmax .
  • the UE 404 may determine the number D of the first set of time-domain bases to generate based on information received from the base station 402 –for example, the base station 402 may configure the number D of the first set of time-domain bases to be used for time-domain compression of CSI reporting.
  • the UE 404 may transmit information reporting the selected number D to the base station 402 (e.g., the UE 404 may select the number D of the first set of time-domain bases to generate and transmit information indicating D or information indicating to the base station 402) .
  • the number D of the first set of time-domain bases to generate may be based on at least one technical specification or standard promulgated by a standards organization (e.g., a 3GPP technical specification) .
  • the number D of the first set of time-domain bases to generate may be indicated in the at least one technical specification or standard, such as by indicating a fixed value of D (or fixed value of the scalar ⁇ ) or by indicating a set of rules or formulas to be followed or evaluated for determining or calculating a value of D (e.g., the set of rules or formulas may include a set of variables and, accordingly, the base station 402 or the UE 404 may determine a corresponding value or other parameter for each variable of the set in order to evaluate the set of rules or formulas) .
  • the UE 404 may determine a length N of each of the first set of time-domain bases, which may be equal for each of the first set of time-domain bases.
  • the UE 404 may determine the length N of each of the first set of time-domain bases based on the number of the first set of RSs 420.
  • the number of the first set of RSs 420 may be defined by the cycle with which the UE 404 is configured for CSI reporting. For example, when the UE 404 is configured for periodic CSI reporting, the number of the first set of RSs 420 may be defined by the number of CSI-RSs received during that CSI reporting period.
  • the number of the first set of RSs may be defined by the number transmission occasions of CSI-RSs within a time-domain restriction.
  • the number of the first set of RSs 420 may be configured by the base station 402 and indicated in a message requesting CSI transmitted by the base station 402 to the UE 404.
  • the UE 404 may determine the length N of each of the first set of time-domain bases based on the number N of the first set of RSs 420, for example, because the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c upon which the UE 404 determines CSI for the cycle corresponding to the first set of RSs 420 may be indexed by or correspond to time instances of #0 through #N-1.
  • the UE 404 may derive D time-domain bases, each being of length N.
  • W d [d 0 , d 1 , ..., d D-1 ] .
  • the UE 404 may, in the time domain, compress CSI, each of which may be represented as x (n) .
  • W d may be multiplied by a set of linear combination coefficients.
  • the number of the set of linear combination coefficients may be equal to the number of time-domain bases (here, D) , and each of the linear combination coefficients may be denoted by ⁇ k .
  • Each of the linear combination coefficients ⁇ k may be associated with a respective time-domain basis of the first set of time-domain bases –for example, d 0 may be associated with ⁇ 0 .
  • the UE 404 may derive each of the set of linear combination coefficients based on W d and based on each of the CSI x (n) . For example, the UE 404 may derive each of the set of linear combination coefficients according to Equation 4.
  • the UE 404 may multiply W d by the set of linear combination coefficients [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T .
  • the multiplication for time-domain compression may be equal to a summation function of a time-domain compression function d ⁇ (n) ⁇ ⁇ , indexed by a time instance ⁇ from 0 to D-1. Equation 5 illustrates the time-domain compressed CSI
  • the UE 404 may generate a single CSI report 432 that indicates the time-domain compressed CSI components associated with the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c upon which the UE 404 determines CSI x (n) for the CSI-reporting cycle corresponding to the first set of RSs 420.
  • the UE 404 may generate the single CSI report 432 to indicate time-domain compressed CSI components
  • the UE 404 may transmit the set of linear combination coefficients [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T .
  • the UE 404 may transmit information that explicitly indicates the set of linear combination coefficients, such as by transmitting each value of ⁇ for the set [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T .
  • the UE 404 may implicitly indicate the set of linear combination coefficients by quantizing each of the set of linear combination coefficients.
  • the UE 404 may quantize each value of ⁇ into an amplitude and a phase and, thus, the UE 404 may derive a set of amplitudes and phases based on quantization of the set [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T .
  • the UE 404 may include the information indicating the set of linear combination coefficients in at least one message to be transmitted to the base station 402, such as by including information explicitly indicating the set of linear combination coefficients or by including the set of quantized values corresponding to the set of linear combination coefficients.
  • the UE 404 may include the set of linear combination coefficients in the single CSI report 432.
  • the UE 404 may transmit the set of linear combination coefficients to the base station 402 separately from the single CSI report 432.
  • the base station 402 may receive the set of linear combination coefficients [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T . Based on the time-domain compressed CSI components and the set of linear combination coefficients, the base station 402 may determine 436 the transmission configuration for channel conditions at a next or current time instance N. For example, the base station 402 may determine the time-domain compressed CSI components based on the set of linear combination coefficients [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T and based on the information indicating v Dmax 434.
  • the base station 402 may determine 436 the transmission configuration by predicting CSI at a current or future slot based on CSI reported by the UE 404 for that current or future slot. For example, the base station 402 may configure at least one layer for transmission on the channel of the configured carrier c. Additionally or alternatively, the base station 402 may configure a set of transmission parameters that includes one or more of modulation and coding (e.g., select an MCS) , precoding (e.g., configure a precoding matrix) , spatial processing, a transmission mode, and the like. The base station 402 may then transmit data 438 to the UE 404 at the time instance N, which may be a slot, based on the determined transmission configuration.
  • modulation and coding e.g., select an MCS
  • precoding e.g., configure a precoding matrix
  • spatial processing e.g., configure a precoding matrix
  • the UE 404 may be configured to further reduce computational or signaling overheads experienced by the base station 402 by generating a second set of time-domain bases and using the second set of time-domain bases for time-domain prediction to predict CSI for future time instances, which may further reduce the amount or frequency of CSI reports transmitted by the UE 404 to the base station 402.
  • the UE 404 may be configured to determine 430 a second set of time-domain bases, in addition to the first set of time-domain bases upon which the time-domain compression of CSI may be based.
  • the UE 404 may determine 430 the time-domain bases by generating the second set of time-domain bases based on at least one of the first set of time-domain bases, v Dmax , or one or more future time instances that are preceded in time by the time instances of the first set of RSs 420 (e.g., time instances of N to T-1, which may be n N , ..., n T-1 ) .
  • each of the second set of time-domain bases may be a Slepian basis, a fractional DFT basis, or another basis suitable for a band-limited deterministic model.
  • the UE 404 may determine a length (denoted as T) of each of the second set of time-domain bases.
  • the UE 404 may determine the length T of each of the second set of time-domain bases based on information received from the base station 402 –e.g., the base station 402 may configure the length T of each of the second set of time-domain bases to be used for time-domain prediction.
  • the base station 402 may transmit a request for CSI reporting (e.g., in DCI or in a MAC control element) to the UE 404, and the request for CSI reporting may indicate a number of future time instances that are preceded in time by the time instances of the first set of RSs 420. This number of future time instances that are preceded in time by the time instances of the first set of RSs 420 may correspond to the length T of each of the second set of time-domain bases.
  • the UE 404 may select the length T of each of the second set of time-domain bases, and the UE 404 may transmit information reporting the selected length T to the base station 402. For example, the UE 404 may transmit, to the base station 402, reporting information indicating where ⁇ is a scalar. In another example, the UE 404 may determine the length T of each of the second set of time-domain bases based on N, which may be a future or current time instance (e.g., a slot) . In a further example, the length T of each of the second set of time-domain bases may be defined in at least one technical specification or standard promulgated by a standards organization (e.g., a 3GPP technical specification) .
  • a standards organization e.g., a 3GPP technical specification
  • the length T of each of the second set of time-domain bases may be indicated in the at least one technical specification or standard, such as by indicating a fixed value of T (or fixed value of the scalar ⁇ ) or by indicating a set of rules or formulas to be followed or evaluated for determining or calculating a value of T (e.g., the set of rules or formulas may include a set of variables and, accordingly, the base station 402 or the UE 404 may determine a corresponding value or other parameter for each variable of the set in order to evaluate the set of rules or formulas) .
  • the time instance of the first set of CSI-RSs 420 and the time instance of the predicted CSI may be determined based on the time unit of the max Doppler frequency, and/or the time unit after adjusted by the scaling factor.
  • the UE 404 may determine the number of the second set of time-domain bases.
  • the UE 404 may determine that the number of the second set of time-domain bases is equal to the number D of the first set of time-domain bases –e.g., the UE 404 may generate D time-domain bases of the first set and, further, may generate D time-domain bases of the second set.
  • the UE 404 may determine D based on v Dmax , based on information received from the base station 402, based on the length T of each of the second set of time-domain bases, based on reporting information transmitted by the UE 404 (e.g., or where ⁇ is a scalar) , or based on information indicated in at least one technical specification or standard promulgated by a standards organization (e.g., a 3GPP technical specification) .
  • a standards organization e.g., a 3GPP technical specification
  • the number D of the second set of time-domain bases to generate may be indicated in the at least one technical specification or standard, such as by indicating a fixed value of D (or fixed value of the scalar ⁇ ) or by indicating a set of rules or formulas to be followed or evaluated for determining or calculating a value of D (e.g., the set of rules or formulas may include a set of variables and, accordingly, the base station 402 or the UE 404 may determine a corresponding value or other parameter for each variable of the set in order to evaluate the set of rules or formulas) .
  • the base station 402 or the UE 404 may determine the actual time instances corresponding to future CSI N, ..., T-1 (e.g., CSI associated with the one or more future time instances that are preceded in time by the time instances of the first set of RSs 420) .
  • each of the actual time instances may be a time or value corresponding to a time (e.g., an index or other identifier of a time-domain resource, such as a slot or symbol) .
  • the actual time instances corresponding to future CSI N, ..., T-1 may be configured by the base station 402 and transmitted to the UE 404.
  • the UE 404 may determine the actual time instances corresponding to future CSI N, ..., T-1 and may transmit information indicating the determined actual time instances corresponding to future CSI N, ..., T-1 to the base station 402.
  • the actual time instances corresponding to future CSI N, ..., T-1 may be indicated in the at least one technical specification or standard, such as by indicating a fixed value associated with the actual time instances corresponding to future CSI N, ..., T-1 (e.g., by indicating N, ..., T-1) or by indicating a set of rules or formulas to be followed or evaluated for determining or calculating the actual time instances corresponding to future CSI N, ..., T-1.
  • the UE 404 may derive D time-domain bases of the second set, each having length T.
  • the first set of time-domain bases may be d 0 (0, 1, ..., N-1) , ..., d D-1 (0, ..., N-1)
  • the second set of time-domain bases for time-domain prediction may be d 0 (N, ..., T-1) , ..., d D-1 (N, ..., T-1) .
  • the UE 404 may compress CSI x (n) in the time domain based on d 0 (0, 1, ..., N-1) , ..., d D-1 (0, ..., N-1) .
  • the UE 404 may not determine CSI x (N) , ..., x (T-1) based on received CSI-RSs, because a time instance N may be a current or future time instance in which a CSI-RS has not been received by the UE 404 or not been transmitted by the base station 402.
  • At least a portion of the time-domain bases of W d may be multiplied by a set of linear combination coefficients.
  • Each of the linear combination coefficients may be denoted by ⁇ k .
  • the UE 404 may derive the set of linear combination coefficients based on at least one of W d , CSI x (0) , ..., x (N-1) associated with the first set of RSs 420, or CSI x (N) , ..., x (T-1) associated with the one or more future time instances that are preceded in time by the time instances of the first set of RSs 420.
  • the UE 404 may derive at least a portion of the set of linear combination coefficients based on d 0 (0, 1, ..., N-1) , ..., d D-1 (0, ..., N-1) and CSI x (0) , ..., x (N-1) , for example, as shown according to Equation 6.
  • Equation 6 may contain the first D rows of W d .
  • the UE 404 may derive at least another portion of the set of linear combination coefficients based on d 0 (0, 1, ..., N-1) , ..., d D-1 (0, ..., T-1) and CSI x (0) , ..., x (T-1) , for example, as shown in Equation 7.
  • the UE 404 may multiply W d by the set of linear combination coefficients [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T .
  • the multiplication for time-domain compression and time-domain prediction may be equal to a summation function of a time-domain function d ⁇ (n) ⁇ ⁇ , indexed by a time instance ⁇ from 0 to D-1. Equation 8 illustrates the time-domain compressed CSI components and time-domain predicted CSI components CSI
  • the UE 404 may generate a single CSI report 432 based on the time-domain compressed CSI components and time-domain predicted CSI components CSI For example, the UE 404 may generate the single CSI report 432 to indicate at least information for deriving the time-domain predicted CSI In some aspects, the UE 404 may omit information explicitly indicating the time-domain predicted CSI components from the single CSI report 432.
  • the UE 404 may transmit the set of linear combination coefficients [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T generated for time-domain compression and time-domain prediction, for example, so that the base station 402 may reconstruct at least the time-domain predicted CSI components
  • the UE 404 may explicitly or implicitly indicate the set of linear combination coefficients. For example, the UE 404 may explicitly indicate the set of linear combination coefficients by including each value of each of the set of linear combination coefficients in at least one message transmitted to the base station 402. In another example, the UE 404 may implicitly indicate the set of linear combination coefficients by quantizing each of the set of linear combination coefficients, and including the quantized values in at least one message transmitted to the base station 402. The UE 404 may quantize each of the set of linear combination coefficients by quantizing each of the set of linear combination coefficients into an amplitude and a phase.
  • the UE 404 may include the set of linear combination coefficients in the single CSI report 432. In another aspect, the UE 404 may transmit the set of linear combination coefficients to the base station 402 separately from the single CSI report 432.
  • the base station 402 may receive the set of linear combination coefficients [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T .
  • the base station 402 may then determine the time-domain compressed CSI components based at least on the single CSI report 432 and based on the set of linear combination coefficients [ ⁇ 0 , ⁇ 1 , ..., ⁇ D-1 ] T . From the time-domain compressed CSI components the base station 402 may determine 436 the transmission configuration for the channel conditions of the channel.
  • the base station 402 may determine 436 the transmission configuration by receiving, from the UE 404, information indicating a time-domain prediction of CSI for a current or future slot and, further, by configuring a set of transmission parameters based on the received time-domain prediction of CSI.
  • the base station 402 may configure at least one layer for the channel of the configured carrier c.
  • the base station 402 may configure one or more of modulation and coding (e.g., select an MCS) , precoding (e.g., configure a precoding matrix) , spatial processing, transmission mode, and the like.
  • the base station 402 may then transmit data 438 to the UE 404 based on the determined transmission configuration.
  • the UE 404 may transmit information indicating a set of linear combination coefficients to the base station 402 that is specific to a spatial-domain basis (e.g., beam) and specific to a subband of a system bandwidth.
  • a precoder of the UE 404 or a precoder of the base station 402 for one layer on the specific subband may be illustrated in Equation 9.
  • c i, m, l may be the linear combination coefficient for the i th spatial basis (e.g., a beam)
  • W 2 may be a 2L ⁇ 1 matrix including all linear combination coefficients on the specific subband.
  • W 1 may be a N t ⁇ 2L matrix including all spatial-domain bases.
  • the UE 404 may transmit information indicating the set of spatial-domain bases (e.g., W 1 ) to the base station 402, and the set of spatial-domain bases may be invariant across CSI associated with the occasions of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • the UE 404 may linearly combine at least one spatial-domain bases (e.g., according to Equation 9) across the specific subband or wideband of the system bandwidth in order to configure precoding for at least one layer of the UE 404 or the base station 402.
  • the UE 404 may apply time-domain compression to the linear combination coefficients before transmission to the base station 402.
  • the time-domain compression of the linear combination coefficients by the UE 404 may be based on a number of the first set of RSs 420, such as the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c, which may be N-bundled CSI-RS transmission occasions.
  • the UE 404 may first determine CSI. Further, the UE 404 may determine 430 a set of time-domain bases (e.g., based on at least v Dmax or based on each time instance of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c) .
  • a set of time-domain bases e.g., based on at least v Dmax or based on each time instance of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c
  • the UE 404 may determine a set of linear combination coefficients ⁇ k, i , each of which may be associated with a respective spatial-domain basis of the spatial-domain bases W 1 and associated with one subband (or a wideband) of the system bandwidth. For example, the UE 404 may determine W 2 (0) , W 2 (1) , ..., W 2 (N-1) .
  • the UE 404 may then apply time-domain compression for each corresponding linear combination coefficient across W 2 (0) , W 2 (1) , ..., W 2 (N-1) , for example, based on a time-domain basis d (n) . To do so, the UE 404 may model each entry in W 2 (n) as a band-limited process, as shown in Equation 10.
  • d ⁇ (n) may be a time-domain basis.
  • Each linear combination coefficient ⁇ ⁇ , i may be for ⁇ th time basis on the i th spatial basis (e.g., a beam) , and may also be specific to the subband of the system bandwidth.
  • the UE 404 may transmit at least one CSI report 432 to the base station 402.
  • the UE 404 may additionally transmit information indicating W 1 to the base station 402.
  • the base station 402 may calculate precoder values (e.g., as shown in Equation 9) . In combination with the at least one CSI report 432, the base station 402 may determine 436 the transmission configuration for channel conditions on the channel, and may transmit data 438 to the UE 404 based on the determined transmission configuration.
  • each linear combination coefficient may be associated with a respective combination of a spatial-domain basis and a frequency-domain basis.
  • the precoder of the UE 404 and the precoder of the base station 402 for one layer on N 3 subbands may be illustrated in Equation 11.
  • Equation 11 c i, m, l may be the linear combination coefficient for the i th spatial basis (e.g., a beam) and the m th frequency basis, and may be a 2L ⁇ M matrix including all linear combination coefficients.
  • the spatial domain may be a N t ⁇ 1 spatial-domain basis
  • W 1 may be a N t ⁇ 2L matrix including all spatial-domain bases.
  • the frequency domain may be a 1 ⁇ N 3 frequency-domain basis, and may be the Hermitian of a M ⁇ N 3 matrix including all frequency-domain bases.
  • the UE 404 may transmit information indicating the set of spatial-domain bases (e.g., W 1 ) and the set of frequency-domain bases (e.g., W f ) to the base station 402, and both the frequency-domain bases and the spatial-domain bases may be invariant across CSI associated with the occasions of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • the UE 404 and the base station 402 may respectively linearly combine a set of spatial-domain bases and a set of frequency-domain bases (e.g., according to Equation 11) in order to respectively configure precoding for at least one layer of the UE 404 or the base station 402.
  • the UE 404 may apply time-domain compression to the linear combination coefficients for the precoder before transmission to the base station 402.
  • the time-domain compression of the linear combination coefficients by the UE 404 may be based on a number of the first set of RSs 420, such as the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c, which may be N-bundled CSI-RS transmission occasions.
  • the UE 404 may first determine CSI. Further, the UE 404 may determine 430 a set of time-domain bases (e.g., based on at least v Dmax or based on each time instance of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c) .
  • a set of time-domain bases e.g., based on at least v Dmax or based on each time instance of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c
  • the UE 404 may determine a set of linear combination coefficients ⁇ k, i, m , each of which may be associated with a respective spatial-domain basis of the spatial-domain bases W 1 and associated with a respective frequency-domain basis of the frequency-domain bases W f . For example, the UE 404 may determine The UE 404 may then apply time-domain compression for each corresponding linear combination coefficient across for example, based on a time-domain basis d (n) . To do so, the UE 404 may model each entry in as a band-limited process, as shown in Equation 12.
  • d ⁇ (n) may be a time-domain basis.
  • Each linear combination coefficient ⁇ ⁇ , i, m may be for ⁇ th time basis on the i th spatial basis (e.g., a beam) and m th frequency basis.
  • the UE 404 may transmit, to the base station 402 a single CSI report 432 corresponding to the first set of RSs 420.
  • the UE 404 may additionally transmit information indicating W 1 and W f to the base station 402.
  • the base station 402 may calculate precoder values (e.g., as shown in Equation 11) . In combination with the CSI report 432, the base station 402 may determine 436 the transmission configuration for channel conditions of the channel, and may transmit data 438 to the UE 404 based on the determined transmission configuration.
  • the UE 404 may generate a set of time-domain bases based on v Dmax .
  • the UE 404 may determine 430 a set of time-domain bases by first generating a correlation matrix in the time domain using v Dmax and, optionally, a scaling factor ⁇ .
  • the UE 404 may first generate a set of sequences based on v Dmax .
  • each of the set of sequences may be an eigenvector of a matrix R.
  • the length of each sequence generated by the UE 404 may be equal to N'.
  • N' may be configured by the base station 402 and transmitted to the UE 404.
  • the UE 404 may determine N' based at least in part on the time instance of the most recent CSI-RS transmission occasion. For example, the UE 404 may determine N' based at least in part on the time instance of the transmission occasion of the last RS of the first set of RSs 420 (that is, CSI-RS #N-1 422c) .
  • the UE 404 may determine N' based at least in part on the time instance of the most recent message requesting CSI received from the base station 402 (e.g., a message configuring the UE 404 for aperiodic CSI reporting) .
  • the scaling factor ⁇ may cause an adjustment in the resolution of time-domain compression or, for future time-instances, time-domain prediction. That is, the scaling factor ⁇ may cause a change to correlated time intervals. For example, v Dmax may be based on a time interval T S , as shown in Equation 3, and the scaling factor ⁇ may increase or decrease the granularity of the time interval. Thus, if time interval T S is one slot, and the scaling factor ⁇ is 0.5, the scaling factor ⁇ may cause an adjust of time-domain compression from one slot to one-half slot. In some aspects, the scaling factor ⁇ may be 1 and, therefore, Equation 13 may be equal to Equation 2.
  • the UE 404 may perform a decomposition of the correlation matrix R. For example, when the UE 404 generates each sequence as N′ ⁇ 1 eigenvectors of the matrix R, the UE 404 may perform an eigenvalue decomposition of the correlation matrix R to a set of N′ ⁇ 1 eigenvectors The UE 404 may then select the first D eigenvectors of R.
  • the UE 404 may extract a subsequence from each sequence based on the time instances of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • n k may be the time instance of CSI-RS #k of the first set of RSs 420 (e.g., n 1 may be CSI-RS #1 422b) according to the time unit (e.g., a slot) of the sampling rate T S .
  • the first time instance n 0 or n initial of CSI-RS #0 422a may be preconfigured or may be configurable (e.g., configured by the base station 402 and signaled to the UE 404) , and the difference between time instances may be even (e.g., consistent) or may be uneven (e.g., different between different pairs of time instances) .
  • the UE 404 extracts subsequences from the first D eigenvectors the time-domain bases may be
  • the UE 404 may extract entries from each of the eigenvectors based on future time instances of CSI request for prediction, which may be indicated in a message from the base station 402 (e.g., for aperiodic CSI reporting) . For example, the UE 404 may extract the n k entry from The extracted time-domain bases for time-domain prediction, then, may be
  • the UE 404 may derive the time-domain bases for prediction based on each N′ ⁇ 1 eigenvector and based on the time future time instances of CSI request for prediction, according to Equation 14.
  • the UE 404 may extract a submatrix from the correlation matrix R based on the time instances of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c. For example,
  • time instance n may be associated with one of the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c upon which the UE 404 determines CSI x (n) for the CSI-reporting cycle corresponding to the first set of RSs 420.
  • the first time instance n 0 or n initial of CSI-RS #0 422a may be preconfigured or may be configurable (e.g., configured by the base station 402 and signaled to the UE 404) , and the difference between time instances may be even (e.g., consistent) or may be uneven (e.g., different between different pairs of time instances) .
  • the UE 404 may determine d ⁇ , which may be of size N ⁇ 1, as the ⁇ th eigenvector of Alternatively, to generate the time-domain bases for time-domain prediction, the UE 404 may derive the time-domain bases based on each N ⁇ 1 eigenvector d 0 , ..., d D-1 and based on the time future time instances of CSI requested for prediction, according to Equation 15.
  • FIGS 5A and 5B are a flowchart of a method 500 of wireless communication by a UE.
  • the method may be performed by a UE (e.g., the UE 104; the UE 350, which may include the memory 360 and which may be the entire UE 350 or a component of the UE 350, such as the TX processor 368, the RX processor 356, or the controller/processor 359; the UE 404) .
  • a UE e.g., the UE 104; the UE 350, which may include the memory 360 and which may be the entire UE 350 or a component of the UE 350, such as the TX processor 368, the RX processor 356, or the controller/processor 359; the UE 404
  • one or more operations may be omitted, transposed, and/or contemporaneously performed.
  • the UE may receive a first set of CSI-RSs from a base station.
  • the UE 404 may receive the first set of RSs 420, including the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c, from the base station 402.
  • the UE may determine a Doppler frequency based on a carrier on which communication with the base station is configured. For example, the UE may determine the Doppler frequency v Dmax based on a carrier c on which communication with the base station is configured and further based on a speed v of the UE, as shown in Equation 3, supra.
  • the Doppler frequency may be a maximum Doppler frequency associated with fading on at least one channel of the carrier on which the communication with the base station is configured.
  • the UE may determine the Doppler frequency further based on a unit associated with a time-domain resource, which may be a symbol or a slot.
  • the UE 404 may determine 428 the Doppler frequency v Dmax based on a carrier on which communication with the base station 402 is configured.
  • the UE may determine a first set of time-domain bases based on at least one of the Doppler frequency or each time instance of each of the first set of CSI-RSs.
  • the length of each time-domain basis of the first set of time-domain bases is equal to a number of transmission occasions associated with the first set of CSI-RSs.
  • the UE 404 may determine 430 a first set of time-domain bases based on at least one of the Doppler frequency or each time instance of each of the first set of CSI-RSs.
  • the UE may determine a second set of time-domain bases based on at least one of the first set of time-domain bases, the Doppler frequency, or a set of future time instances preceded by the first set of CSI-RSs.
  • the number of the second set of time-domain bases may be equal to the number of the first set of time-domain bases.
  • a length of each of the second set of time-domain bases may be equal to a number of a set of future time instances preceded by the first set of CSI-RSs.
  • the set of future time instances preceded by the first set of CSI-RSs may be based on at least one of information received from the base station, preconfigured information stored in the UE, a number of transmission occasions associated with the first set of CSI-RSs, a set of time instances that is each associated with a respective CSI-RS of the first set of CSI-RSs, or information transmitted to the base station.
  • the UE 404 may determine 430 a second set of time-domain bases based on at least one of the first set of time-domain bases, the Doppler frequency, or a set of future time instances preceded by the first set of CSI-RSs.
  • the UE may determine the first set of time-domain bases by, first, generating a correlation matrix associated with the time domain based on the Doppler frequency.
  • the UE may generate the correlation matrix further based on a scaling factor associated with adjustment of a duration of a unit of time associated with the Doppler frequency.
  • the UE may perform a decomposition (e.g., an eigenvalue decomposition) of the correlation matrix.
  • the UE may determine the first set of time-domain bases based on the decomposition of the correlation matrix and further based on at least one of a set of time instances that is each associated with a respective CSI-RS of the first set of CSI-RSs or a set of future time instances preceded by the first set of CSI-RSs.
  • the UE may determine the first set of time-domain bases by, first, generating a correlation matrix associated with the time domain based on the Doppler frequency.
  • the UE may generate the correlation matrix further based on a scaling factor associated with adjustment of a duration of a unit of time associated with the Doppler frequency.
  • the UE may extract a submatrix of the correlation matrix based on respective time instances corresponding to each CSI-RS of the first set of CSI-RSs.
  • the UE may select an eigenvector of the submatrix based on the time instance of a CSI-RS of the first set of CSI-RSs, and the time instance of the CSI-RS of the first set of CSI-RSs may index the selected eigenvector.
  • the UE may determine the first set of time-domain bases based on the submatrix and further based on at least one of a set of time instances that is each associated with a respective CSI-RS of the first set of CSI-RSs or a set of future time instances preceded in time by the first set of CSI-RSs.
  • the UE may determine a set of sequences associated with a time domain based on the Doppler frequency, and the number of the set of sequences may be equal to a number of the first set of time-domain bases.
  • the set of sequences may be determined further based on a scaling factor associated with adjustment of a duration of a unit of time associated with the Doppler frequency.
  • at least one of the first set of time-domain bases or the second set of time-domain bases may be determined based on the set of sequences.
  • the length of a respective one of the set of sequences may be configured (e.g., by the base station or by the UE) or, alternatively, may be determined based on a time instance of a most-recent transmission occasion of one of the first set of CSI-RSs corresponding to the respective one of the set of sequences or a next time instance after the time instance of the most-recent transmission occasion.
  • Each entry of each of the set of sequences may be applied to a respective time instance of a set of continuous time instances.
  • the UE may extract a subsequence of each of the set of sequences to obtain a set of subsequences based on a mapping between each time instances of each transmission occasion of the first set of CSI-RSs and a respective index of each of the set of sequences.
  • the mapping may include a time instance of a transmission occasion of the earliest CSI-RS of the first set of CSI-RSs mapped to an initial index of each of the set of sequences.
  • the mapping may further include each time instance of each transmission occasions of the first set of CSI-RSs other than the earliest CSI-RS mapped to the respective index of each of the set of sequences based on each difference between each time instance of each transmission occasion of the first set of CSI-RSs other than the earliest CSI-RS and the time instance of the transmission occasion of the earliest CSI-RS of the first set of CSI-RSs.
  • the first set of time-domain bases may be based on this set of subsequences extracted from the set of sequences.
  • the UE may extract a subsequence from each of the set of sequences to obtain a set of subsequences based on a mapping between each of the plurality of future time instances and a respective index of each of the set of sequences.
  • the mapping may include a time instance of a transmission occasion associated with the earliest CSI-RS of the first set of CSI-RSs mapped to an initial index of each of the set of sequences.
  • the mapping may further include each of the plurality of future time instances preceded by the first set of CSI- RSs mapped to an index of one of the set of sequences based on each difference between each of the plurality of future time instances preceded by the first set of CSI-RSs and the time instance of the transmission occasion of the earliest CSI-RS of the first set of CSI-RSs.
  • the second set of time-domain bases may be based on this set of subsequences extracted from the set of sequences.
  • the UE may determine, for each of the set of sequences, a linear combination of each entry of a sequence of the set of sequences to obtain a set of linear combinations based on at least one of the set of linear combination coefficients. For the determination of each linear combination, at least one of the set of linear combination coefficients may be determined based on at least one of plurality of future time instances preceded by the first set of CSI-RSs. The second set of time-domain bases may be determined based on this set of linear combinations.
  • the time instance of the first set of CSI-RSs 420 and the time instance of the predicted CSI may be determined based on the time unit of the max Doppler frequency, and/or the time unit after adjusted by the scaling factor.
  • Each of the time-domain bases of the first set and the second set may be a Slepian basis. However, another basis may be used for each of the time-domain bases. For example, each of the time-domain bases of the first set and the second set may be a fractional DFT basis.
  • the UE may determine a first set of CSI based on the first set of CSI-RSs. For example, referring to Figure 4, the UE 404 may determine a first set of CSI based on the first set of RSs 420.
  • the UE may determine a set of linear combination coefficients based on the first set of time-domain bases and based on the first set of CSI. In a further aspect, the UE may determine the set of linear combination coefficients based on the second set of time-domain bases. In addition, the UE may determine the set of linear combination coefficients based on another set of CSI that is based on the set of future time instances preceded in time by the first set of CSI-RSs. Each of the set of linear combination coefficients may be associated with a respective time-domain basis of the first set of time-domain bases or the second set of time-domain bases. For example, referring to Figure 4, the UE 404 may determine a set of linear combination coefficients based on the first set of time-domain bases and based on the first set of CSI.
  • the UE may determine a second set of CSI based on at least one of the first set of time-domain bases or the set of linear combination coefficients.
  • the second set of CSI may be a time-domain compression of the first set of CSI.
  • the UE may determine the second set of CSI based on multiplication of the first set of time-domain bases with the set of linear combination coefficients, as shown in Equation 5, supra.
  • the UE 404 may determine a second set of CSI based on at least one of the first set of time-domain bases or the set of linear combination coefficients.
  • the UE may determine a third set of CSI based on at least one of the first set of time-domain bases, the second set of time-domain bases, or the set of linear combination coefficients.
  • the third set of CSI may be associated with the set of future time instances preceded in time by the first set of CSI-RSs.
  • the third set of CSI may be a time-domain prediction of the other set of CSI that is based on the set of future time instances preceded in time by the first set of CSI-RSs.
  • the UE may determine the third set of CSI based on multiplication of the second set of time-domain bases with the set of linear combination coefficients, as shown in Equation 8, supra.
  • the UE 404 may determine a third set of CSI based on at least one of the first set of time-domain bases, the second set of time-domain bases, or the set of linear combination coefficients.
  • the UE may transmit at least one CSI report to the base station based on the first set of CSI-RSs. For example, the UE may determine CSI corresponding to each CSI-RS of the first set of CSI-RSs. In one aspect, the UE may transmit a CSI report corresponding to each CSI-RS of the set of CSI-RSs. In another aspect, the UE may transmit a single CSI report for all CSI-RSs of the first set of CSI-RSs.
  • the UE may transmit a single CSI report that includes a time-domain compression (e.g., the second set of CSI) for all CSI-RSs of the first set of CSI-RSs and includes a time-domain prediction (e.g., the third set of CSI) for future time instances preceded in time by the first set of CSI-RSs.
  • a time-domain compression e.g., the second set of CSI
  • a time-domain prediction e.g., the third set of CSI
  • the UE may determine the CSI to include in the at least one CSI report by performing a linear combination of the set of linear combination coefficients and a set of spatial domain bases.
  • the set of spatial-domain bases may be invariant across CSI associated with each CSI-RS of the first set of CSI-RSs.
  • each linear combination coefficient of the set of linear combination coefficients is associated with a corresponding subband of a system bandwidth.
  • the UE may perform the linear combination by linearly combining the set of linear combination coefficients, the set of spatial domain bases, and a set of frequency domain bases.
  • the set of frequency-domain bases may be invariant across CSI associated with each CSI-RS of the first set of CSI-RSs.
  • the UE may determine CSI for a single CSI report based on the linear combination.
  • the UE may transmit information indicating the set of linear combination coefficients to the base station.
  • the UE may include information indicating the set of linear combination coefficients in the single CSI report, or the UE may transmit the set of linear combination coefficients separately from the single CSI report.
  • the UE 404 may transmit at least one CSI report 432 to the base station based on the first set of RSs 420.
  • the UE may transmit information indicating the Doppler frequency to the base station.
  • the UE may include the information indicating the Doppler frequency in each of the at least one CSI reports or in the single CSI report.
  • the UE may transmit the information indicating the Doppler frequency to the base station separately from the at least one CSI report.
  • the information indicating the Doppler frequency may be a quantized value of the Doppler frequency or may be a level corresponding to the Doppler frequency.
  • the UE 404 may transmit the Doppler frequency information 434 to the base station 402.
  • Figure 6 is a flowchart of a method 600 of wireless communication by a base station.
  • the method may be performed by a base station (e.g., the base station 102/180; the base station 310, which may include the memory 376 and which may be the entire base station 310 or a component of the base station 310, such as the TX processor 316, the RX processor 370, or the controller/processor 375; the base station 402) .
  • a base station e.g., the base station 102/180; the base station 310, which may include the memory 376 and which may be the entire base station 310 or a component of the base station 310, such as the TX processor 316, the RX processor 370, or the controller/processor 375; the base station 402
  • one or more operations may be omitted, transposed, and/or contemporaneously performed.
  • the base station may transmit a first set of CSI-RSs.
  • the base station 402 may transmit the first set of RSs 420, including the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • the base station may receive, from a UE, at least one CSI report associated with the first set of CSI-RSs.
  • the base station may receive a set of CSI reports associated with the first set of CSI-RSs, and each CSI report of the set of CSI reports may be associated with a respective CSI-RS of the first set of CSI-RSs.
  • the base station may receive a single CSI report, which may indicate CSI associated with each CSI-RS of the first set of CSI-RSs.
  • the base station 402 may receive the at least one CSI report 432 associated with the first set of RSs 420, including the CSI-RS #0 422a, CSI-RS #1 422b, ..., CSI-RS #N-1 422c.
  • the base station may receive, from the UE, information indicating a Doppler frequency associated with a carrier on which communication with the UE is configured.
  • the Doppler frequency may be a maximum Doppler frequency associated with fading on at least one channel of the carrier on which the communication with the base station is configured.
  • the Doppler frequency may be associated with a unit of a time-domain resource, such as a duration of a symbol or a slot.
  • the base station 402 may receive information indicating the Doppler frequency v Dmax 434 from the UE 404.
  • the information indicating the Doppler frequency may be included in the at least one CSI report received from the UE.
  • the base station may receive the information indicating the Doppler frequency in a message that is separate from the at least one CSI report received from the UE.
  • the information indicating the Doppler frequency may be a quantized value of the Doppler frequency.
  • the information indicating the Doppler frequency may be one level corresponding to the Doppler frequency (e.g., one level of a set of different levels that each corresponds with a different Doppler frequency or different range of Doppler frequencies) .
  • the base station may receive, from the UE, information indicating a set of linear combination coefficients.
  • the set of linear combination coefficients may be associated with the single CSI report received from the UE.
  • the set of linear combination coefficients may be associated with a time-domain compression of CSI indicated in the single CSI report.
  • the set of linear combination coefficients may be associated with a time-domain prediction of CSI corresponding to a set of future time instances preceded by the first set of CSI-RSs.
  • the base station 402 may receive, from the UE 404, information indicating the set of linear combination coefficients.
  • the base station 402 may receive the information indicating the set of linear combination coefficients in one of the message that also includes the information indicating the Doppler frequency v Dmax 434, the single CSI report 432, or a message that is separate from the message including the information indicating the Doppler frequency v Dmax 434 and the single CSI report 432.
  • the base station may determine a first set of time-domain bases based on at least the Doppler frequency.
  • the length of each time-domain basis of the first set of time-domain bases is equal to a number of transmission occasions associated with the first set of CSI-RSs.
  • a number of each time-domain basis of the first set of time-domain bases may be configured by the base station, may be indicated by at least one technical specification associated with a radio access technology for the communication with the UE, may be based on the Doppler frequency, or may be reported by the UE.
  • each linear combination coefficient of the set of linear combination coefficients may be associated with a respective time-domain basis of the first set of time-domain bases.
  • the base station 402 may determine a first set of time-domain bases based on at least the Doppler frequency. For example, the base station 402 may determine the first set of time-domain bases similarly to the UE 404, as shown by the determination 430 of the first set of time-domain bases based on at least one of the Doppler frequency or each time instance of each of the first set of CSI-RSs.
  • the base station may determine a second set of time-domain bases based on at least one of the first set of time-domain bases, the Doppler frequency, or the single CSI report.
  • the number of the second set of time-domain bases may be equal to the number of the first set of time-domain bases.
  • a length of each of the second set of time-domain bases may be equal to a number of a set of future time instances preceded by the first set of CSI-RSs.
  • the set of future time instances preceded by the first set of CSI-RSs may be based on at least one of information configured by the base station, information received from the UE, a number of transmission occasions associated with the first set of CSI-RSs, a set of time instances that is each associated with a respective CSI-RS of the first set of CSI-RSs.
  • the base station 402 may determine a second set of time-domain bases based on at least one of the first set of time-domain bases, the Doppler frequency, or the single CSI report 432. For example, the base station 402 may determine the second set of time-domain bases similarly to the UE 404, as shown by the determination 430 of the second set of time-domain bases based on at least one of the first set of time-domain bases, the Doppler frequency, or a set of future time instances preceded by the first set of CSI-RSs.
  • the base station may determine the first set of time-domain bases by, first, generating a correlation matrix associated with the time domain based on the Doppler frequency.
  • the base station may generate the correlation matrix further based on a scaling factor associated with adjustment of a duration of a unit of time associated with the Doppler frequency.
  • the base station may perform a decomposition (e.g., an eigenvalue decomposition) of the correlation matrix.
  • the base station may determine the first set of time-domain bases based on the decomposition of the correlation matrix and further based on at least one of a set of time instances that is each associated with a respective CSI-RS of the first set of CSI-RSs or a set of future time instances preceded by the first set of CSI-RSs.
  • the base station may determine the first set of time-domain bases by, first, generating a correlation matrix associated with the time domain based on the Doppler frequency.
  • the base station may generate the correlation matrix further based on a scaling factor associated with adjustment of a duration of a unit of time associated with the Doppler frequency.
  • the base station may extract a submatrix of the correlation matrix based on respective time instances corresponding to each CSI-RS of the first set of CSI-RSs.
  • the base station may select an eigenvector of the submatrix based on the time instance of a CSI-RS of the first set of CSI-RSs, and the time instance of the CSI-RS of the first set of CSI-RSs may index the selected eigenvector.
  • the base station may determine the first set of time-domain bases based on the submatrix and further based on at least one of a set of time instances that is each associated with a respective CSI-RS of the first set of CSI-RSs or a set of future time instances preceded in time by the first set of CSI-RSs.
  • the base station may determine a set of sequences associated with a time domain based on the Doppler frequency, and the number of the set of sequences may be equal to a number of the first set of time-domain bases.
  • the set of sequences may be determined further based on a scaling factor associated with adjustment of a duration of a unit of time associated with the Doppler frequency.
  • at least one of the first set of time-domain bases or the second set of time-domain bases may be determined based on the set of sequences.
  • the length of a respective one of the set of sequences may be configured (e.g., by the base station or by the UE) or, alternatively, may be determined based on a time instance of a most-recent transmission occasion of one of the first set of CSI-RSs corresponding to the respective one of the set of sequences or a next time instance after the time instance of the most-recent transmission occasion.
  • Each entry of each of the set of sequences may be applied to a respective time instance of a set of continuous time instances.
  • the base station may extract a subsequence of each of the set of sequences to obtain a set of subsequences based on a mapping between each time instances of each transmission occasion of the first set of CSI-RSs and a respective index of each of the set of sequences.
  • the mapping may include a time instance of a transmission occasion of the earliest CSI-RS of the first set of CSI-RSs mapped to an initial index of each of the set of sequences.
  • the mapping may further include each time instance of each transmission occasions of the first set of CSI-RSs other than the earliest CSI-RS mapped to the respective index of each of the set of sequences based on each difference between each time instance of each transmission occasion of the first set of CSI-RSs other than the earliest CSI-RS and the time instance of the transmission occasion of the earliest CSI-RS of the first set of CSI-RSs.
  • the first set of time-domain bases may be based on this set of subsequences extracted from the set of sequences.
  • the base station may extract a subsequence from each of the set of sequences to obtain a set of subsequences based on a mapping between each of the plurality of future time instances and a respective index of each of the set of sequences.
  • the mapping may include a time instance of a transmission occasion associated with the earliest CSI-RS of the first set of CSI-RSs mapped to an initial index of each of the set of sequences.
  • the mapping may further include each of the plurality of future time instances preceded by the first set of CSI-RSs mapped to an index of one of the set of sequences based on each difference between each of the plurality of future time instances preceded by the first set of CSI-RSs and the time instance of the transmission occasion of the earliest CSI-RS of the first set of CSI-RSs.
  • the second set of time-domain bases may be based on this set of subsequences extracted from the set of sequences.
  • the UE may determine, for each of the set of sequences, a linear combination of each entry of a sequence of the set of sequences to obtain a set of linear combinations based on at least one of the set of linear combination coefficients. For the determination of each linear combination, at least one of the set of linear combination coefficients may be determined based on at least one of plurality of future time instances preceded by the first set of CSI-RSs. The second set of time-domain bases may be determined based on this set of linear combinations.
  • Each of the time-domain bases of the first set and the second set may be a Slepian basis. However, another basis may be used for each of the time-domain bases. For example, each of the time-domain bases of the first set and the second set may be a fractional DFT basis.
  • the base station may determine a first set of CSI components based on at least one of the single CSI report, the set of linear combination coefficients, or the first set of time-domain bases.
  • the first set of CSI components may be associated with the first set of CSI-RSs.
  • the first set of CSI components may be based on a time-domain compression of CSI associated with the single CSI report.
  • the first set of CSI components may approximate CSI indicated in each of those set of CSI reports associated with the first set of CSI-RSs.
  • the first set of CSI components may be determined based on the first set of time-domain bases, the second set of time-domain bases, the Doppler frequency, or the set of linear combination coefficients.
  • the first set of CSI components may be further associated with the set of future time instances preceded by the first set of CSI-RSs.
  • at least a portion of the CSI components may be based on a time-domain prediction of CSI associated with the single CSI report.
  • the base station 402 may determine a first set of CSI components based on at least one of the single CSI report 432, the set of linear combination coefficients, or the first set of time-domain bases. For example, the base station 402 may reconstruct the first set of CSI components according to Equation 5, supra. In another example, the base station 402 may reconstruct the first set of CSI components according to Equation 8, supra.
  • the base station may determine a transmission configuration associated with data transmission to the UE on the configured carrier based on the at least one CSI report and based on the Doppler frequency. For example, the base station may determine the transmission configuration based on the first set of CSI components, which may be determined based on the at least one CSI report and based on the Doppler frequency. In some aspects, to determine the transmission configuration, the base station may configure at least one of a MCS, precoding, spatial processing, a transmission layer, or a transmission mode based on the at least one CSI report and based on the Doppler frequency (e.g., based on the first set of CSI components) . For example, referring to Figure 4, the base station 402 may determine a transmission configuration on the configured carrier c based on the at least one CSI report 432 and based on the information indicating the Doppler frequency v Dmax 434.
  • the base station may transmit data to the UE based on the transmission configuration.
  • the base station may use one of a MCS, precoding, spatial processing, a transmission layer, or a transmission mode, which may be configured based on the at least one CSI report and based on the information indicating the Doppler frequency, in order to transmit data to the UE.
  • the base station 402 may transmit data 438 to the UE 404 based on a determination 436 of the transmission configuration.
  • Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, or C, and may include multiples of A, multiples of B, or multiples of C.
  • combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C.

Abstract

Selon un aspect, l'invention concerne un procédé, un support lisible par ordinateur et un appareil. L'appareil peut être un UE. L'appareil peut être configuré pour recevoir un premier ensemble de CSI-RS provenant d'une station de base. L'appareil peut exécuter les étapes consistant à : déterminer une fréquence Doppler sur la base d'une porteuse sur laquelle une communication avec la station de base est configurée ; sur la base du premier ensemble de CSI-RS, transmettre au moins un rapport de CSI à la station de base ; et transmettre à la station de base des informations indiquant la fréquence Doppler.
PCT/CN2019/095750 2019-07-12 2019-07-12 Système et procédé de rapport d'état de canal et d'informations sur une fréquence doppler WO2021007695A1 (fr)

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PCT/CN2019/115073 WO2021008007A1 (fr) 2019-07-12 2019-11-01 Système et procédé de rapport d'état de canal et d'informations de fréquence doppler
PCT/CN2020/101290 WO2021008450A1 (fr) 2019-07-12 2020-07-10 Système et procédé de rapport d'état de canal et informations de fréquence doppler

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