WO2021042349A1 - Techniques de détermination et de signalement d'informations d'état de canal - Google Patents

Techniques de détermination et de signalement d'informations d'état de canal Download PDF

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Publication number
WO2021042349A1
WO2021042349A1 PCT/CN2019/104623 CN2019104623W WO2021042349A1 WO 2021042349 A1 WO2021042349 A1 WO 2021042349A1 CN 2019104623 W CN2019104623 W CN 2019104623W WO 2021042349 A1 WO2021042349 A1 WO 2021042349A1
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WIPO (PCT)
Prior art keywords
state information
channel state
base station
different
reference signal
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Application number
PCT/CN2019/104623
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English (en)
Inventor
Ruifeng MA
Bo Chen
Pavan Kumar Vitthaladevuni
Yu Zhang
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Qualcomm Incorporated
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Priority to PCT/CN2019/104623 priority Critical patent/WO2021042349A1/fr
Publication of WO2021042349A1 publication Critical patent/WO2021042349A1/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
    • H04B7/0617—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 for beam forming
    • 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
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0686—Hybrid systems, i.e. switching and simultaneous transmission
    • H04B7/0695—Hybrid systems, i.e. switching and simultaneous transmission using beam selection

Definitions

  • the following relates generally to wireless communications, and more specifically to channel state information determination and reporting techniques.
  • Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) .
  • Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems.
  • 4G systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems
  • 5G systems which may be referred to as New Radio (NR) systems.
  • a wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .
  • UE user equipment
  • a UE may measure one or more reference signals (e.g., a channel state information reference signal (CSI-RS) ) to estimate channel quality between a base station and the UE.
  • channel quality may be indicated by one or more parameters that are determined based on the measurements, such as a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , a layer one reference signal received power (L1-RSRP) , or combinations thereof.
  • the UE may transmit a measurement report (e.g., a CSI report) to the base station indicating the channel quality information that the base station may use to determine parameters for communications with the UE.
  • CSI-RS channel state information reference signal
  • a CSI resource set may include two or more CSI resources for a UE.
  • the UE may measure two or more CSI reference signals (CSI-RSs) in the two or more CSI resources that are transmitted using different beamforming parameters, and perform beam selection across the two or more CSI resources.
  • CSI-RSs CSI reference signals
  • the CSI resources are selected by a base station based on one or more sounding reference signal (SRS) transmissions of the UE that are transmitted using fewer antenna ports than are used at the UE for receiving downlink transmissions.
  • SRS sounding reference signal
  • the UE may provide an indication of the selected beams. If the UE selects a beam for communications within one CSI resource, the UE may provide an indication of the resource index and port selection associated with the CSI resource.
  • a method of wireless communications at a UE may include transmitting, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE, receiving, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, selecting a first set of beamforming parameters based on measurements of the two or more channel state information reference signals, and transmitting an indication of the set of beamforming parameters to the base station.
  • the apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory.
  • the instructions may be executable by the processor to cause the apparatus to transmit, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE, receive, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, select a first set of beamforming parameters based on measurements of the two or more channel state information reference signals, and transmit an indication of the set of beamforming parameters to the base station.
  • the apparatus may include means for transmitting, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE, receiving, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, selecting a first set of beamforming parameters based on measurements of the two or more channel state information reference signals, and transmitting an indication of the set of beamforming parameters to the base station.
  • a non-transitory computer-readable medium storing code for wireless communications at a UE is described.
  • the code may include instructions executable by a processor to transmit, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE, receive, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, select a first set of beamforming parameters based on measurements of the two or more channel state information reference signals, and transmit an indication of the set of beamforming parameters to the base station.
  • At least two of the two or more channel state information reference signals may be transmitted using different precoder types.
  • the different precoder types include an eigen vector-based precoder and a discrete fourier transform (DFT) beam-based precoder.
  • DFT discrete fourier transform
  • each of the two or more different channel state information resources correspond to one of the different precoder types or a combination of the different precoder types.
  • Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the base station, configuration information that indicates the two or more different channel state information resources within the channel state information resource set.
  • the configuration information may be received in RRC signaling from the base station.
  • a number of channel state information reference signal resources within the channel state information resource set may be determined based on a first number of antennas available for transmitting signals from the UE, a second number of antennas available for receiving signals at the UE, and the number of polarizations of base station.
  • the transmitting may include operations, features, means, or instructions for formatting a bitmap to indicate that the first set of beamforming parameters are determined based on a first channel state information reference signal and a second channel state information reference signal of the two or more channel state information reference signals, and transmitting the bitmap to the base station.
  • the transmitting may include operations, features, means, or instructions for transmitting a resource index for each of a first channel state information reference signal and a second channel state information reference signal of the two or more channel state information reference signals that are used to determine the first set of beamforming parameters.
  • the transmitting may include operations, features, means, or instructions for formatting a channel state information report that includes a resource indication that indicates whether the first set of beamforming parameters is determined based on a single channel state information resource within the channel state information resource set or is determined based on multiple different channel state information resources within the channel state information resource set.
  • the channel state information report includes a first part that provides a rank indicator, a channel quality indicator, a number of beamforming coefficients reported per layer, and the resource indication, and where the channel state information report includes a second part that provides a precoding matrix indicator corresponding to the beamforming coefficients reported for each layer and, when the resource indication indicates that multiple different channel state information resources were used to determine the first set of beamforming parameters, an identification of which channel state information resources were selected.
  • a method of wireless communications at a base station may include receiving, from a UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE, transmitting, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, and receiving a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory.
  • the instructions may be executable by the processor to cause the apparatus to receive, from a UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE, transmit, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, and receive a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the apparatus may include means for receiving, from a UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE, transmitting, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, and receiving a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • a non-transitory computer-readable medium storing code for wireless communications at a base station is described.
  • the code may include instructions executable by a processor to receive, from a UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE, transmit, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, and receive a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • At least two of the two or more channel state information reference signals may be transmitted using different precoder types.
  • the different precoder types include an eigen vector-based precoder and a discrete fourier transform (DFT) beam-based precoder.
  • DFT discrete fourier transform
  • each of the two or more different channel state information resources correspond to one of the different precoder types or a combination of the different precoder types.
  • Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the UE, an indication that a reduced number of transmission antennas are available at the UE, and transmitting, to the UE, configuration information that indicates the two or more different channel state information resources within the channel state information resource set.
  • the configuration information may be transmitted in RRC signaling.
  • a number of channel state information reference signal resources within the channel state information resource set may be determined based on a first number of antennas available for transmitting signals from the UE, a second number of antennas available for receiving signals at the UE, and the number of polarizations of base station.
  • the channel state information report includes a bitmap to indicate that the first set of beamforming parameters is determined based on a first channel state information reference signal and a second channel state information reference signal of the two or more channel state information reference signals.
  • the channel state information report includes a resource index for each of a first channel state information reference signal and a second channel state information reference signal of the two or more channel state information reference signals that were used to determine the first set of beamforming parameters.
  • the channel state information report includes a resource indication that indicates whether the first set of beamforming parameters is determined based on a single channel state information resource within the channel state information resource set or is determined based on multiple different channel state information resources within the channel state information resource set.
  • the channel state information report includes a first part that provides a rank indicator, a channel quality indicator, a number of beamforming coefficients reported per layer, and the resource indication, and where the channel state information report includes a second part that provides a precoding matrix indicator corresponding to the beamforming coefficients reported for each layer and, when the resource indication indicates that the multiple different channel state information resources were used to determine the first set of beamforming parameters, an identification of which channel state information resources were selected.
  • FIG. 1 illustrates an example of a system for wireless communications that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIG. 2 illustrates an example of a wireless communications system that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIG. 3 illustrates an example of a CSI resource set configuration that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIGs. 4A and 4B illustrate examples of CSI reports in accordance with aspects of the present disclosure.
  • FIG. 5 illustrates an example of a process flow that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIGs. 6 and 7 show block diagrams of devices that support channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIG. 8 shows a block diagram of a communications manager that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIG. 9 shows a diagram of a system including a device that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIGs. 10 and 11 show block diagrams of devices that support channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIG. 12 shows a block diagram of a communications manager that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIG. 13 shows a diagram of a system including a device that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • FIGs. 14 through 17 show flowcharts illustrating methods that support channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • a user equipment may report channel state information (CSI) feedback to a base station for multiple transmission beams.
  • the base station may construct a precoding matrix and may precode transmissions over the multiple beams for communications with the UE.
  • the CSI feedback may include bit representations for a number of precoding coefficients (e.g., a wide-band amplitude scaling factor, a sub-band amplitude scaling factor, a beam combination coefficient corresponding to a phase value, etc. ) with respect to a particular beam, polarity, and layer number.
  • the CSI feedback may include a bit representation for each reporting sub-band of the BWP.
  • a UE may choose a set of beams for which the UE generates beam parameters, and may provide feedback based on a beam combination codebook.
  • Some beam combination codebooks (including, e.g., a New Radio (NR) Type II codebook) , may be designed to facilitate relatively high performance (e.g., high throughput) for use with some communications systems.
  • NR New Radio
  • reciprocity-based beamforming may be implemented in which beamforming parameters for uplink transmissions are determined based on beamforming parameters for downlink transmissions, assuming channel reciprocity for uplink and downlink channels.
  • a base station may transmit one or more a CSI reference signals (CSI-RSs) in a beam scanning procedure, in which the base station may determine the scanning precoder basis for a downlink CSI-RS based on an eigen-vector decomposition (e.g., a singular value decomposition (SVD) ) or 2D discrete Fourier transform (DFT) codebook structure.
  • CSI-RSs CSI reference signals
  • an eigen-vector decomposition e.g., a singular value decomposition (SVD)
  • DFT discrete Fourier transform
  • a UE may transmit using one transmit port and receive using four receive ports (i.e., a 1T4R configuration) , or use two transmit antenna ports and four receive ports (i.e., a 2T4R configuration) .
  • the UE may transmit an uplink reference signal (e.g., a sounding reference signal (SRS) ) using the configured antenna port (s) .
  • SRS sounding reference signal
  • a receiving base station may be able to obtain limited channel information on which to derive beamforming parameters for the downlink transmissions.
  • the base station may adopt an eigen-based precoder basis for a scan, which may provide suitable parameters for less than all available transmission layers (e.g., for the first two or four layers) , and may constrain the support of higher rank transmissions to the UE.
  • the base station may also adopt a DTF-based precoder basis for a scan, which may provide support for higher rank transmissions but may suffer from performance loss due to quantization error.
  • each resource set may be configured with one CSI resource that may be measured at the UE, and a UE CSI report is provided based on the single CSI-RS resource.
  • CSI reports that can contain additional information related to measurements of the multiple CSI resources.
  • the UE may provide to the base station CSI feedback based on multiple CSI-RS measurements of multiple CSI resources within a CSI resource set.
  • the CSI report may include a first portion and a second portion, where the first portion of the CSI report may indicate whether multiple CSI resources were used to identify CSI report parameters for the second portion of the CSI report–that is, indicating whether the second portion of the CSI report includes parameters (e.g., beamforming coefficients (W 2 ) ) based on two or more CSI resources.
  • the second portion of the CSI report may provide CSI feedback and may also indicate which CSI resources were used for the CSI feedback.
  • the CSI resources used for the CSI feedback may be indicated in a bitmap of the configured CSI resources.
  • the CSI resources may be indicated by a CSI resource index that is provided for each CSI resource used for the CSI feedback.
  • Such techniques for configuring multiple CSI resources in a CSI resource set, and for providing CSI feedback for the configured CSI resources may thus provide more reliable beam candidates to UE without significant CSI-RS overhead increase, relative to deployments in which a single CSI resource is configured and reported in a CSI report.
  • Such techniques further may improve the performance under partial-CSI by UE looping through different beam combinations based on the multiple CSI resources, in order to provide an enhanced CSI report to the base station.
  • DFT-based beams of higher layers may also be refined based on the enhanced measurements at the UE.
  • Such enhanced beamforming parameters allow for communications using beams that more accurately reflect channel conditions, and thereby enhance the efficiency and reliability of wireless communications.
  • aspects of the disclosure are initially described in the context of a wireless communications system. Various examples of CSI resource configurations and reports are then discussed. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to channel state information determination and reporting techniques.
  • FIG. 1 illustrates an example of a wireless communications system 100 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the wireless communications system 100 includes base stations 105, UEs 115, and a core network 130.
  • the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network.
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • LTE-A Pro LTE-A Pro
  • NR New Radio
  • wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices.
  • ultra-reliable e.g., mission critical
  • Base stations 105 may wirelessly communicate with UEs 115 via one or more base station antennas.
  • Base stations 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or some other suitable terminology.
  • Wireless communications system 100 may include base stations 105 of different types (e.g., macro or small cell base stations) .
  • the UEs 115 described herein may be able to communicate with various types of base stations 105 and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.
  • Each base station 105 may be associated with a particular geographic coverage area 110 in which communications with various UEs 115 is supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 110 via communication links 125, and communication links 125 between a base station 105 and a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions.
  • the geographic coverage area 110 for a base station 105 may be divided into sectors making up a portion of the geographic coverage area 110, and each sector may be associated with a cell.
  • each base station 105 may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof.
  • a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110.
  • different geographic coverage areas 110 associated with different technologies may overlap, and overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or by different base stations 105.
  • the wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations 105 provide coverage for various geographic coverage areas 110.
  • the term “cell” refers to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) , and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) ) operating via the same or a different carrier.
  • a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC) , narrowband Internet-of-Things (NB-IoT) , enhanced mobile broadband (eMBB) , or others) that may provide access for different types of devices.
  • MTC machine-type communication
  • NB-IoT narrowband Internet-of-Things
  • eMBB enhanced mobile broadband
  • the term “cell” may refer to a portion of a geographic coverage area 110 (e.g., a sector) over which the logical entity operates.
  • UEs 115 may be dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile.
  • a UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client.
  • a UE 115 may also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer.
  • PDA personal digital assistant
  • a UE 115 may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles, meters, or the like.
  • WLL wireless local loop
  • IoT Internet of Things
  • IoE Internet of Everything
  • MTC massive machine type communications
  • Some UEs 115 may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) .
  • M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention.
  • M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application.
  • Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.
  • Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications) . In some cases, UEs 115 may be designed to support critical functions (e.g., mission critical functions) , and a wireless communications system 100 may be configured to provide ultra-reliable communications for these functions.
  • critical functions e.g., mission critical functions
  • a UE 115 may also be able to communicate directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol) .
  • P2P peer-to-peer
  • D2D device-to-device
  • One or more of a group of UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105.
  • Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105, or be otherwise unable to receive transmissions from a base station 105.
  • groups of UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group.
  • a base station 105 facilitates the scheduling of resources for D2D communications.
  • D2D communications are carried out between UEs 115 without the involvement of a base
  • Base stations 105 may communicate with the core network 130 and with one another.
  • base stations 105 may interface with the core network 130 through backhaul links 132 (e.g., via an S1, N2, N3, or other interface) .
  • Base stations 105 may communicate with one another over backhaul links 134 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) .
  • the core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions.
  • the core network 130 may be an evolved packet core (EPC) , which may include at least one mobility management entity (MME) , at least one serving gateway (S-GW) , and at least one Packet Data Network (PDN) gateway (P-GW) .
  • the MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the EPC.
  • User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW.
  • the P-GW may provide IP address allocation as well as other functions.
  • the P-GW may be connected to the network operators IP services.
  • the operators IP services may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched (PS) Stream
  • At least some of the network devices may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC) .
  • Each access network entity may communicate with UEs 115 through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP) .
  • TRP transmission/reception point
  • various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 105) .
  • Wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) .
  • the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length.
  • UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.
  • HF high frequency
  • VHF very high frequency
  • Wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band.
  • SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that may be capable of tolerating interference from other users.
  • ISM bands 5 GHz industrial, scientific, and medical bands
  • Wireless communications system 100 may also operate in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band.
  • EHF extremely high frequency
  • wireless communications system 100 may support millimeter wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE 115.
  • mmW millimeter wave
  • the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.
  • wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands.
  • wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band.
  • LAA License Assisted Access
  • LTE-U LTE-Unlicensed
  • NR NR technology
  • an unlicensed band such as the 5 GHz ISM band.
  • wireless devices such as base stations 105 and UEs 115 may employ listen-before-talk (LBT) procedures to ensure a frequency channel is clear before transmitting data.
  • LBT listen-before-talk
  • operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) .
  • Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these.
  • Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD) , time division duplexing (TDD) , or a combination of both.
  • FDD frequency division duplexing
  • TDD time division duplexing
  • base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming.
  • wireless communications system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115) , where the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas.
  • MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing.
  • the multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas.
  • Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams.
  • Different spatial layers may be associated with different antenna ports used for channel measurement and reporting.
  • MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.
  • SU-MIMO single-user MIMO
  • MU-MIMO multiple-user MIMO
  • Beamforming which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitting device and the receiving device.
  • Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference.
  • the adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying certain amplitude and phase offsets to signals carried via each of the antenna elements associated with the device.
  • the adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .
  • a base station 105 may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE 115. For instance, some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105.
  • some signals e.g., synchronization signals, reference signals, beam selection signals, or other control signals
  • Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105.
  • Some signals may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) .
  • the beam direction associated with transmissions along a single beam direction may be determined based at least in in part on a signal that was transmitted in different beam directions.
  • a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions, and the UE 115 may report to the base station 105 an indication of the signal it received with a highest signal quality, or an otherwise acceptable signal quality.
  • a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) , or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .
  • a receiving device may try multiple receive beams when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals.
  • a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive beams or receive directions.
  • a receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal) .
  • the single receive beam may be aligned in a beam direction determined based at least in part on listening according to different receive beam directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality based at least in part on listening according to multiple beam directions) .
  • the antennas of a base station 105 or UE 115 may be located within one or more antenna arrays, which may support MIMO operations, or transmit or receive beamforming.
  • one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower.
  • antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations.
  • a base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115.
  • a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.
  • wireless communications system 100 may be a packet-based network that operate according to a layered protocol stack.
  • PDCP Packet Data Convergence Protocol
  • a Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels.
  • RLC Radio Link Control
  • a Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels.
  • the MAC layer may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency.
  • HARQ hybrid automatic repeat request
  • the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or core network 130 supporting radio bearers for user plane data.
  • RRC Radio Resource Control
  • transport channels may be mapped to physical channels.
  • UEs 115 and base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully.
  • HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link 125.
  • HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) .
  • FEC forward error correction
  • ARQ automatic repeat request
  • HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions) .
  • a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.
  • the radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023.
  • SFN system frame number
  • Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms.
  • a subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods.
  • a subframe may be the smallest scheduling unit of the wireless communications system 100, and may be referred to as a transmission time interval (TTI) .
  • TTI transmission time interval
  • a smallest scheduling unit of the wireless communications system 100 may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs) .
  • a slot may further be divided into multiple mini-slots containing one or more symbols.
  • a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling.
  • Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example.
  • some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE 115 and a base station 105.
  • carrier refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link 125.
  • a carrier of a communication link 125 may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology.
  • Each physical layer channel may carry user data, control information, or other signaling.
  • a carrier may be associated with a pre-defined frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) , and may be positioned according to a channel raster for discovery by UEs 115.
  • E-UTRA evolved universal mobile telecommunication system terrestrial radio access
  • E-UTRA absolute radio frequency channel number
  • Carriers may be downlink or uplink (e.g., in an FDD mode) , or be configured to carry downlink and uplink communications (e.g., in a TDD mode) .
  • signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) .
  • MCM multi-carrier modulation
  • OFDM orthogonal frequency division multiplexing
  • DFT-S-OFDM discrete Fourier transform spread OFDM
  • the organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR) .
  • communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data.
  • a carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc. ) and control signaling that coordinates operation for the carrier.
  • acquisition signaling e.g., synchronization signals or system information, etc.
  • control signaling that coordinates operation for the carrier.
  • a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.
  • Physical channels may be multiplexed on a carrier according to various techniques.
  • a physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques.
  • control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces) .
  • a carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100.
  • the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) .
  • each served UE 115 may be configured for operating over portions or all of the carrier bandwidth.
  • some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .
  • a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .
  • a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related.
  • the number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme) .
  • the more resource elements that a UE 115 receives and the higher the order of the modulation scheme the higher the data rate may be for the UE 115.
  • a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers) , and the use of multiple spatial layers may further increase the data rate for communications with a UE 115.
  • a spatial resource e.g., spatial layers
  • Devices of the wireless communications system 100 may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths.
  • the wireless communications system 100 may include base stations 105 and/or UEs 115 that support simultaneous communications via carriers associated with more than one different carrier bandwidth.
  • Wireless communications system 100 may support communication with a UE 115 on multiple cells or carriers, a feature which may be referred to as carrier aggregation or multi-carrier operation.
  • a UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration.
  • Carrier aggregation may be used with both FDD and TDD component carriers.
  • a base station 105 may precode one or more transmissions to a UE 115 according to a precoding matrix indicator (PMI) codebook used for spatial channel information feedback.
  • the base station 105 may use a specific PMI codebook format based on the rank of the one or more transmissions. For example, if the transmissions have a rank of 1, the precoding matrix W may be a 2 ⁇ 1 matrix equal to a spatial domain compression matrix W 1 multiplied by a coefficient matrix W 2 , where W may be normalized to 1. If the transmissions have a rank of 2, the precoding matrix may be a 2 ⁇ 2 matrix equal to a spatial domain compression matrix W 1 multiplied by a coefficient matrix W 2 , where columns of W may be normalized to
  • the precoding matrix W may be a l x r matrix, where l corresponds to a number of layers and r corresponds to rank, that has entries
  • the base station 105 may determine the precoding matrix (i.e., the precoder) according to where L may correspond to a total number of transmission beams, may correspond to an oversampled two-dimensional (2D) DFT beam, may correspond to a wideband amplitude scaling factor, may correspond to a sub-band amplitude scaling factor, and c r, l, i may correspond to a beam combining coefficient.
  • L may be configurable (e.g., L ⁇ ⁇ 2, 3, 4 ⁇ ) .
  • an amplitude scaling mode may be configured (e.g., by the base station 105) as either a wideband and sub-band mode (e.g., with unequal bit allocation) or a wideband-only mode.
  • the techniques disclosed herein may enable a UE 115 and a base station 105 to maintain a relatively high level of performance in partial-CSI deployments.
  • the base station 105 may identify that a UE 115 is operating in a partial-CSI mode (e.g., in a 1T4R or 2T4R configuration) and may configure two or more CSI resources in a CSI resource set, and transmit two or more CSI-RSs for measurement at the UE 115.
  • the UE 115 may measure the CSI-RSs, and may provide to the base station 105 CSI feedback report.
  • the UE 115 may provide an indication of the selected beams in the CSI feedback report. If the UE 115 selects a beam for communications within one CSI resource, the UE 115 may provide an indication to the base station 105 of the resource index and port selection associated with the CSI resource.
  • FIG. 2 illustrates an example of a wireless communications system 200 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • wireless communications system 200 may implement aspects of wireless communications system 100.
  • wireless communications system 200 may include a base station 105-a and a UE 115-a, which may be examples of the corresponding devices as described with reference to FIG. 1.
  • the base station 105-a may provide network coverage for a geographic coverage area 110-a.
  • the UE 115-a may transmit CSI feedback 210 to the base station 105-a on an uplink channel 205.
  • the UE 115-a may transmit spatial channel information feedback in the CSI feedback 210, such as beamforming coefficients and an indication of one or more selected CSI resources.
  • the UE 115-a may transmit an uplink reference signal, such as a SRS, using an uplink beam 220 using an uplink port (e.g., according to a 1T4R configuration) .
  • the UE 115-a may measure one or more CSI reference signals from the base station 105-a at one or more receive antenna ports.
  • the CSI reference signals may be transmitted via one or more beams 215.
  • the UE 115-a may utilize CSI measurements to determine one or more coefficients (e.g., a wideband beam amplitude scaling factor, a sub-band beam amplitude scaling factor, a beam combining coefficient, etc. ) corresponding to a precoding matrix W and to generate a bit representation of each coefficient.
  • coefficients e.g., a wideband beam amplitude scaling factor, a sub-band beam amplitude scaling factor, a beam combining coefficient, etc.
  • Each coefficient may be associated with a set of possible coefficient values for different beam, polarity, and layer combinations.
  • the UE 115-a may choose the set of beams for which the UE 115-a generates the coefficients and provide feedback based on a beam combination codebook.
  • the CSI-RSs may be transmitted using two or more CSI resources that are configured in a CSI resource set.
  • the base station 105-a may utilize, based on the SRS, a combination precoder set of eigen-based and DFT-based precoders to apply on beamformed CSI-RSs.
  • the base station 105-a may then scan beamformed CSI-RSs that occupy the multiple CSI resources in one resource set, as will be discussed in more detail in FIG. 3.
  • each CSI resource may correspond to a specific precoder type (e.g., eigen-based or DFT-based) , or combination of eigen-based and DFT-based beams.
  • the UE 115-a may perform beam selection across the multiple CSI resources. If the selected beams are within different CSI resources, the UE 115-a may feedback a bit mapping sequence, or a CSI resource index, to indicate the selected beams. Otherwise, the UE 115-a may feedback the resource index and port selection when beam selection is from one CSI resource. In some cases, the base station 105-a may configure the UE 115-a to provide such CSI reports (e.g., using RRC signaling to indicate enabling a CSI report of beam selection across CSI-RS resources) . Exemplary CSI reports based on multiple CSI resources are discussed with reference to FIGs, 4A and 4B.
  • the base station 105-a may use the bit representation of the coefficients from the CSI report in conjunction with layer, polarity, and/or beam information (e.g., beam information as determined from a beam combination codebook) to calculate a precoding matrix W (e.g., as described with reference to FIG. 1) .
  • the base station 105-a may determine to communicate with the UE 115-a over base station beams 215. As such, the base station 105-a may identify coefficient values corresponding to the beams from the CSI feedback 210 and may use those values when calculating the precoding matrix W.
  • the base station 105-a may select a precoder from a codebook to use for precoding transmissions to the UE 115-a, where the precoder is associated with the calculated precoding matrix.
  • the base station 105-a may accordingly communicate with the UE 115-a using the uplink beam 220 and one or more base station beam 215-d.
  • FIG. 3 illustrates an example of a CSI resource set configuration 300 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • CSI resource set configuration 300 may implement aspects of wireless communications system 100 or 200.
  • a CSI resource set 305 may be configured that includes a number of different CSI resources 310 through 325.
  • a base station may configure the CSI resource set 305 and multiple different CSI resources 310 through 325 at a UE via RRC signaling, and may also enable beam selection across resources at the UE via RRC signaling.
  • the UE may have a 1T4R configuration, and the base station may configure four CSI resources.
  • a first CSI resource 310 may provide SVD-based CSI-RS precoding using precoder sets ⁇ S 0 , S 1 ⁇ , for two ports with two polarizations. Due to the single SRS transmit port in such a case, the base station may not be able to determine an eigen-based precoder for higher ranks, and thus other CSI resources may be DFT-based.
  • second CSI resource 315 may provide DFT-based CSI-RS precoding using precoder sets ⁇ B i1 , B i2 ⁇ , for two ports with two polarizations.
  • a third CSI resource 320 may provide DFT-based CSI-RS precoding using precoder sets ⁇ B i3 , B i4 ⁇ , for two ports with two polarizations.
  • fourth CSI resource 325 may provide DFT-based CSI-RS precoding using precoder sets ⁇ B i5 , B i6 ⁇ , for two ports with two polarizations.
  • each resource has an orthogonal CSI-RS port on each polarization (i.e., for a total of two ports with two polarizations in this example) .
  • each CSI resource 310 through 325 may belong to certain category, such as SVD-based or DFT-based.
  • the base station may determine the CSI resources 310 through 325 based on a UE reported transmit/receive configuration, or the CSI resources 310 through 325 may be flexibly configured. While four CSI resources 310 through 325 are illustrated, it is to be understood that more or fewer CSI resources may be present.
  • the UE may measure CSI-RSs in the configured CSI resources 310 through 325, and select one of more beams based on the measurements.
  • the UE may select a first beam 330, a third beam 340, and a fifth beam 350 based on cross-resource beam selection, which in this example leaves a second beam 335, a fourth beam 345, a sixth beam 355, a seventh beam 360, and an eighth beam 365 unselected.
  • the UE in some cases, may provide an indication of the selected beams in a feedback report along with the CSI feedback, as will be discussed in more detail with reference to FIGs. 4A and 4B.
  • FIGs. 4A and 4B illustrate examples of CSI reports 400 in accordance with aspects of the present disclosure.
  • CSI reports 400 may implement aspects of wireless communications system 100 or 200.
  • a UE may provide to a base station CSI report 405-a that is determined based on multiple CSI resources, in which a bitmap 425 is used to indicate selected beams in cases where CSI feedback is determined across resources.
  • the UE may provide to the base station CSI report 405-b that is determined based on multiple CSI resources, in which a CSI resource indexe (CRI) 440 is used to indicate selected beams in cases where CSI feedback is determined across resources.
  • CRI CSI resource indexe
  • the CSI report 405-a may include a first portion 410-a and a second portion 415-a.
  • the first portion 410-a of the CSI report 405-a may include, for example, a rank indicator (RI) , a channel quality indicator (CQI) , an indication of the number of non-zero wideband amplitude coefficients per layer, and an across-resource indication 420-a that indicates whether the UE determined the CSI feedback across CSI resources or not (e.g., based on a bit value of 1 or 0) .
  • RI rank indicator
  • CQI channel quality indicator
  • an across-resource indication 420-a that indicates whether the UE determined the CSI feedback across CSI resources or not (e.g., based on a bit value of 1 or 0) .
  • the second portion 415-a of the CSI report 405-a may include, for example, PMI value (s) (e.g., W 2 435-a) corresponding to the number of coefficients indicated in the first portion 410-a of the CSI report 405-a, and in cases where the UE determines the CSI feedback across CSI resources, a bitmap 425 that may include a number of elements 430 corresponding to each of the configured beamforming ports (i.e., N_basis *Beam_num bits in the bitmap, which would correspond to an eight-element bitmap in the example of FIG. 3) .
  • PMI value e.g., W 2 435-a
  • a bitmap 425 may include a number of elements 430 corresponding to each of the configured beamforming ports (i.e., N_basis *Beam_num bits in the bitmap, which would correspond to an eight-element bitmap in the example of FIG. 3) .
  • the CSI report 405-b may include a first portion 410-b and a second portion 415-b.
  • the first portion 410-b of the CSI report 405-b may again include, for example, a RI, a CQI, an indication of the number of non-zero wideband amplitude coefficients per layer, and an across-resource indication 420-b that indicates whether the UE determined the CSI feedback across CSI resources or not (e.g., based on a bit value of 1 or 0) .
  • the second portion 415-b of the CSI report 405-b may include, for example, PMI value (s) (e.g., W 2 435-b) corresponding to the number of coefficients indicated in the first portion 410-b of the CSI report 405-b, and in cases where the UE determines the CSI feedback across CSI resources, a CRI index indication 440 that includes a list of CRIs 445 corresponding to the selected beams (e.g., the CRI of the first beam, third beam, and fifth beam in the example of FIG. 3) .
  • PMI value e.g., W 2 435-b
  • a CRI index indication 440 that includes a list of CRIs 445 corresponding to the selected beams (e.g., the CRI of the first beam, third beam, and fifth beam in the example of FIG. 3) .
  • a fixed payload size for the first portion 410 of the CSI report 405 may be provided, with each field encoded separately and used to identify the number of information bits of the second portion 415 of the CSI report 405.
  • the second portion 415 of the CSI report 405 may include PMI corresponding to indicated non-zero wideband amplitude coefficient per layer, and if the indication of differential beam selection across different CSI resources is present, the bitmap 425 or CRI index indication 440. If the indication of differential beam selection across different CSI resources is present, the second portion 415 in each case may indicate the selected CRI.
  • the second portion 415 may also include wideband and sub-band amplitude feedback, and sub-band co-phase feedback.
  • the CSI reports 400 may be supported for semi-persistent or aperiodic CSI reporting, and can be carried on physical uplink control channel (PUCCH) transmissions (e.g., for the first portion 410 only) , on physical uplink shared channel (PUSCH) transmissions (e.g., for the first portion 410 and second portion 415) , or combinations thereof.
  • PUCCH physical uplink control channel
  • PUSCH physical uplink shared channel
  • the UE may determine a wideband amplitude scaling factor representing an average amplitude of a beam over all reporting sub-bands. Similarly, the UE may determine, for each sub-band, a sub-band amplitude scaling factor representing an amplitude of a beam over a particular reporting sub-band. Further, the UE may determine, for each sub-band, a beam combining coefficient representing a phase or co-phase of a beam over a particular reporting sub-band. The UE may loop through different beam combinations to identify preferable beam (s) based on CSI measurements.
  • the UE may be configured for semi-persistent and/or aperiodic CSI reporting.
  • the UE may transmit the first portion 410-a of the CSI report 405-a using a control channel (e.g., a PUCCH, such as a long PUCCH) and transmit the second portion 415-a of the CSI report 405-a using a shared channel (e.g., a PUSCH) .
  • a control channel e.g., a PUCCH, such as a long PUCCH
  • a shared channel e.g., a PUSCH
  • the UE may transmit the CSI report 405-a without a defined periodicity, for example, based on the occurrence of a trigger (e.g., a request for aperiodic CSI from the base station and/or a condition that the UE or the base station detects, such as a high CQI variation) .
  • a trigger e.g., a request for aperiodic CSI from the base station and/or a condition that the UE or the base station detects, such as a high CQI variation
  • the UE may transmit the CSI report 405-a to the base station periodically at a certain periodicity (e.g., a number of slots) .
  • a certain periodicity e.g., a number of slots
  • the UE may be configured with a periodicity selected from the set of ⁇ 5, 10, 20, 40, 80, 160, 420 ⁇ slots.
  • the UE may, for example, be configured with a relatively longer periodicity if the value for the CSI report 405-a is unlikely to substantially vary at less than the periodicity, or the UE may be configured with a relatively shorter periodicity if the value for the CSI report 405-a is likely to vary more rapidly.
  • FIG. 5 illustrates an example of a process flow 500 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • process flow 500 may implement aspects of wireless communications system 100 or 200.
  • a base station 105 and UE 115 such as a base station 105-b and a UE 115-b, may perform one or more of the processes described with reference to the process flow 500. These processes may be performed according to the CSI configuration and CSI reports, as described with reference to FIGs. 3, 4A, and 4B.
  • Alternative examples of the following may be implemented, where some steps are performed in a different order than described or are not performed at all. In some cases, steps may include additional features not mentioned below, or further steps may be added.
  • the UE 115-b may transmit an uplink reference signal to the base station.
  • the uplink reference signal may be a SRS that is transmitted using one or more configured transmit antenna ports at the UE 115-b.
  • the number of configured transmit antenna ports at the UE 115-b may be less than the number of configured receive antenna ports at the UE 115-b (e.g., according to a 1T4R or 2T4R configuration) .
  • the base station 105-b may transmit a CSI feedback configuration to the UE 115-b.
  • the CSI feedback configuration may indicate a number of CSI resources that are to be monitored at the UE 115-b.
  • the CSI feedback configuration may indicate that the UE 115-b is enabled for performing beam selection across CSI resources.
  • the base station 105-b may transmit to the UE 115-b, and the UE 115-b may receive from the base station 105-b, one or more reference signals (e.g., CSI-RSs) via one or more respective transmit-receive beam pairs.
  • the reference signals may utilize a combination precoder set of eigen-based and DFT-based precoders applied on a beamformed CSI-RS, and beamformed CSI-RS may be scanned across configured CSI resources.
  • Each CSI resource may correspond to a specific precoder type, or combination of eigen-based and DFT-based beams.
  • the UE 115-b may perform CSI measurements on the reference signal transmissions received from the base station 105-b via the one or more beams.
  • performing CSI measurements on the one or more reference signal transmissions may include determining information indicating a RI, a CQI, and/or a number of non-zero wideband amplitude coefficients per layer.
  • performing CSI measurements may be performed across CSI resources.
  • the UE 115-b may perform beam selection across multiple CSI resources.
  • the UE 115-b may measure CSI-RSs received at each CSI resource and identify one or more preferred beams based on the measurements.
  • the UE 115-b may generate the CSI report for a beam combination codebook (e.g., a Type II codebook, such as an NR Type II codebook) for the one or more beams.
  • a beam combination codebook e.g., a Type II codebook, such as an NR Type II codebook
  • the CSI report may include a first portion and a second portion, such as discussed with reference to FIGs. 4A and 4B.
  • the UE 115-b may transmit to the base station 105-b, and the base station 105-b may receive from the UE 115-b, the CSI report, as the UE 115-b may have generated at 530.
  • the UE 115-b may encode the CSI report, for example, the UE 115-b may separately encode first portion and the second portion of the CSI report. That is, the UE 115-b may encode the first portion using a first encoding process to obtain a first codeword and encode the second portion using a second encoding process to obtain a second codeword.
  • the UE 115-b may transmit each of the encoded codewords.
  • the base station 105-b may perform a precoding procedure for the set of beams using the CSI report, as the base station 105-b may have received at 535.
  • the base station 105-b may perform the precoding procedure using the information indicating the PMI and/or the other parameters included in the CSI feedback.
  • the base station 105-b and the UE 115-b may communicate according to the precoding procedure the base station 105-b may have performed at 540.
  • FIG. 6 shows a block diagram 600 of a device 605 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the device 605 may be an example of aspects of a UE 115 as described herein.
  • the device 605 may include a receiver 610, a communications manager 615, and a transmitter 620.
  • the device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • the receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to channel state information determination and reporting techniques, etc. ) . Information may be passed on to other components of the device 605.
  • the receiver 610 may be an example of aspects of the transceiver 920 described with reference to FIG. 9.
  • the receiver 610 may utilize a single antenna or a set of antennas.
  • the communications manager 615 may transmit, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE, receive, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, select a first set of beamforming parameters based on measurements of the two or more channel state information reference signals, and transmit an indication of the set of beamforming parameters to the base station.
  • the communications manager 615 may be an example of aspects of the communications manager 910 described herein.
  • the communications manager 615 may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 615, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.
  • code e.g., software or firmware
  • ASIC application-specific integrated circuit
  • the communications manager 615 may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components.
  • the communications manager 615, or its sub-components may be a separate and distinct component in accordance with various aspects of the present disclosure.
  • the communications manager 615, or its sub-components may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.
  • I/O input/output
  • the transmitter 620 may transmit signals generated by other components of the device 605.
  • the transmitter 620 may be collocated with a receiver 610 in a transceiver module.
  • the transmitter 620 may be an example of aspects of the transceiver 920 described with reference to FIG. 9.
  • the transmitter 620 may utilize a single antenna or a set of antennas.
  • FIG. 7 shows a block diagram 700 of a device 705 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the device 705 may be an example of aspects of a device 605, or a UE 115 as described herein.
  • the device 705 may include a receiver 710, a communications manager 715, and a transmitter 735.
  • the device 705 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • the receiver 710 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to channel state information determination and reporting techniques, etc. ) . Information may be passed on to other components of the device 705.
  • the receiver 710 may be an example of aspects of the transceiver 920 described with reference to FIG. 9.
  • the receiver 710 may utilize a single antenna or a set of antennas.
  • the communications manager 715 may be an example of aspects of the communications manager 615 as described herein.
  • the communications manager 715 may include a SRS manager 720, a CSI-RS manager 725, and a beam selection manager 730.
  • the communications manager 715 may be an example of aspects of the communications manager 910 described herein.
  • the SRS manager 720 may transmit, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE.
  • the CSI-RS manager 725 may receive, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal.
  • the beam selection manager 730 may select a first set of beamforming parameters based on measurements of the two or more channel state information reference signals and transmit an indication of the set of beamforming parameters to the base station.
  • the transmitter 735 may transmit signals generated by other components of the device 705.
  • the transmitter 735 may be collocated with a receiver 710 in a transceiver module.
  • the transmitter 735 may be an example of aspects of the transceiver 920 described with reference to FIG. 9.
  • the transmitter 735 may utilize a single antenna or a set of antennas.
  • FIG. 8 shows a block diagram 800 of a communications manager 805 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the communications manager 805 may be an example of aspects of a communications manager 615, a communications manager 715, or a communications manager 910 described herein.
  • the communications manager 805 may include a SRS manager 810, a CSI-RS manager 815, a beam selection manager 820, a CSI resource manager 825, and a CSI report manager 830. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .
  • the SRS manager 810 may transmit, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE.
  • the CSI-RS manager 815 may receive, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal.
  • at least two of the two or more channel state information reference signals are transmitted using different precoder types.
  • the different precoder types include an eigen vector-based precoder and a discrete Fourier transform (DFT) beam-based precoder.
  • DFT discrete Fourier transform
  • each of the two or more different channel state information resources correspond to one of the different precoder types or a combination of the different precoder types.
  • the beam selection manager 820 may select a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the beam selection manager 820 may transmit an indication of the set of beamforming parameters to the base station.
  • the beam selection manager 820 may format a bitmap to indicate that the first set of beamforming parameters are determined based on a first channel state information reference signal and a second channel state information reference signal of the two or more channel state information reference signals.
  • the beam selection manager 820 may transmit the bitmap to the base station.
  • the CSI resource manager 825 may receive, from the base station, configuration information that indicates the two or more different channel state information resources within the channel state information resource set.
  • the configuration information is received in RRC signaling from the base station.
  • a number of channel state information reference signal resources within the channel state information resource set is determined based on a first number of antennas available for transmitting signals from the UE, a second number of antennas available for receiving signals at the UE, and the number of polarizations of base station.
  • the CSI report manager 830 may transmit a resource index for each of a first channel state information reference signal and a second channel state information reference signal of the two or more channel state information reference signals that are used to determine the first set of beamforming parameters.
  • the CSI report manager 830 may format a channel state information report that includes a resource indication that indicates whether the first set of beamforming parameters is determined based on a single channel state information resource within the channel state information resource set or is determined based on multiple different channel state information resources within the channel state information resource set.
  • the channel state information report includes a second part that provides a precoding matrix indicator corresponding to the beamforming coefficients reported for each layer and, when the resource indication indicates that multiple different channel state information resources were used to determine the first set of beamforming parameters, an identification of which channel state information resources were selected.
  • the channel state information report includes a first part that provides a rank indicator, a channel quality indicator, a number of beamforming coefficients reported per layer, and the resource indication.
  • FIG. 9 shows a diagram of a system 900 including a device 905 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the device 905 may be an example of or include the components of device 605, device 705, or a UE 115 as described herein.
  • the device 905 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 910, an I/O controller 915, a transceiver 920, an antenna 925, memory 930, and a processor 940. These components may be in electronic communication via one or more buses (e.g., bus 945) .
  • buses e.g., bus 945
  • the communications manager 910 may transmit, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE, receive, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, select a first set of beamforming parameters based on measurements of the two or more channel state information reference signals, and transmit an indication of the set of beamforming parameters to the base station.
  • the I/O controller 915 may manage input and output signals for the device 905.
  • the I/O controller 915 may also manage peripherals not integrated into the device 905.
  • the I/O controller 915 may represent a physical connection or port to an external peripheral.
  • the I/O controller 915 may utilize an operating system such as or another known operating system.
  • the I/O controller 915 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device.
  • the I/O controller 915 may be implemented as part of a processor.
  • a user may interact with the device 905 via the I/O controller 915 or via hardware components controlled by the I/O controller 915.
  • the transceiver 920 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above.
  • the transceiver 920 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver.
  • the transceiver 920 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.
  • the wireless device may include a single antenna 925. However, in some cases the device may have more than one antenna 925, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.
  • the memory 930 may include RAM and ROM.
  • the memory 930 may store computer-readable, computer-executable code 935 including instructions that, when executed, cause the processor to perform various functions described herein.
  • the memory 930 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.
  • the processor 940 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) .
  • the processor 940 may be configured to operate a memory array using a memory controller.
  • a memory controller may be integrated into the processor 940.
  • the processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks supporting channel state information determination and reporting techniques) .
  • the code 935 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications.
  • the code 935 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 935 may not be directly executable by the processor 940 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.
  • FIG. 10 shows a block diagram 1000 of a device 1005 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the device 1005 may be an example of aspects of a base station 105 as described herein.
  • the device 1005 may include a receiver 1010, a communications manager 1015, and a transmitter 1020.
  • the device 1005 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • the receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to channel state information determination and reporting techniques, etc. ) . Information may be passed on to other components of the device 1005.
  • the receiver 1010 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13.
  • the receiver 1010 may utilize a single antenna or a set of antennas.
  • the communications manager 1015 may receive, from a UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE, transmit, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, and receive a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the communications manager 1015 may be an example of aspects of the communications manager 1310 described herein.
  • the communications manager 1015 may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 1015, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.
  • code e.g., software or firmware
  • ASIC application-specific integrated circuit
  • the communications manager 1015 may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components.
  • the communications manager 1015, or its sub-components may be a separate and distinct component in accordance with various aspects of the present disclosure.
  • the communications manager 1015, or its sub-components may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.
  • I/O input/output
  • the transmitter 1020 may transmit signals generated by other components of the device 1005.
  • the transmitter 1020 may be collocated with a receiver 1010 in a transceiver module.
  • the transmitter 1020 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13.
  • the transmitter 1020 may utilize a single antenna or a set of antennas.
  • FIG. 11 shows a block diagram 1100 of a device 1105 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the device 1105 may be an example of aspects of a device 1005, or a base station 105 as described herein.
  • the device 1105 may include a receiver 1110, a communications manager 1115, and a transmitter 1135.
  • the device 1105 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • the receiver 1110 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to channel state information determination and reporting techniques, etc. ) . Information may be passed on to other components of the device 1105.
  • the receiver 1110 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13.
  • the receiver 1110 may utilize a single antenna or a set of antennas.
  • the communications manager 1115 may be an example of aspects of the communications manager 1015 as described herein.
  • the communications manager 1115 may include a SRS manager 1120, a CSI-RS manager 1125, and a beam selection manager 1130.
  • the communications manager 1115 may be an example of aspects of the communications manager 1310 described herein.
  • the SRS manager 1120 may receive, from a UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE.
  • the CSI-RS manager 1125 may transmit, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal.
  • the beam selection manager 1130 may receive a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the transmitter 1135 may transmit signals generated by other components of the device 1105.
  • the transmitter 1135 may be collocated with a receiver 1110 in a transceiver module.
  • the transmitter 1135 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13.
  • the transmitter 1135 may utilize a single antenna or a set of antennas.
  • FIG. 12 shows a block diagram 1200 of a communications manager 1205 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the communications manager 1205 may be an example of aspects of a communications manager 1015, a communications manager 1115, or a communications manager 1310 described herein.
  • the communications manager 1205 may include a SRS manager 1210, a CSI-RS manager 1215, a beam selection manager 1220, a CSI resource manager 1225, and a CSI report manager 1230. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .
  • the SRS manager 1210 may receive, from a UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE.
  • the CSI-RS manager 1215 may transmit, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal.
  • at least two of the two or more channel state information reference signals are transmitted using different precoder types.
  • the different precoder types include an eigen vector-based precoder and a discrete Fourier transform (DFT) beam-based precoder.
  • DFT discrete Fourier transform
  • each of the two or more different channel state information resources correspond to one of the different precoder types or a combination of the different precoder types.
  • the beam selection manager 1220 may receive a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the channel state information report includes a bitmap to indicate that the first set of beamforming parameters are determined based on a first channel state information reference signal and a second channel state information reference signal of the two or more channel state information reference signals.
  • the channel state information report includes a resource index for each of a first channel state information reference signal and a second channel state information reference signal of the two or more channel state information reference signals that are used to determine the first set of beamforming parameters.
  • the CSI resource manager 1225 may receive, from the UE, an indication that a reduced number of transmission antennas are available at the UE. In some examples, the CSI resource manager 1225 may transmit, to the UE, configuration information that indicates the two or more different channel state information resources within the channel state information resource set. In some cases, the configuration information is transmitted in RRC signaling.
  • a number of channel state information reference signal resources within the channel state information resource set is determined based on a first number of antennas available for transmitting signals from the UE, a second number of antennas available for receiving signals at the UE, and the number of polarizations of base station.
  • the CSI report manager 1230 may format a channel state information report.
  • the channel state information report includes a first part and a second part.
  • the channel state information report includes a first part that provides a rank indicator, a channel quality indicator, a number of beamforming coefficients reported per layer, and the resource indication.
  • the second part provides a precoding matrix indicator corresponding to the beamforming coefficients reported for each layer and, when the resource indication in the first part indicates that the multiple different channel state information resources were used to determine the first set of beamforming parameters, an identification of which channel state information resources were selected.
  • the channel state information report includes a resource indication that indicates whether the first set of beamforming parameters is determined based on a single channel state information resource within the channel state information resource set or is determined based on multiple different channel state information resources within the channel state information resource set.
  • FIG. 13 shows a diagram of a system 1300 including a device 1305 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the device 1305 may be an example of or include the components of device 1005, device 1105, or a base station 105 as described herein.
  • the device 1305 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1310, a network communications manager 1315, a transceiver 1320, an antenna 1325, memory 1330, a processor 1340, and an inter-station communications manager 1345. These components may be in electronic communication via one or more buses (e.g., bus 1350) .
  • buses e.g., bus 1350
  • the communications manager 1310 may receive, from a UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE, transmit, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal, and receive a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the network communications manager 1315 may manage communications with the core network (e.g., via one or more wired backhaul links) .
  • the network communications manager 1315 may manage the transfer of data communications for client devices, such as one or more UEs 115.
  • the transceiver 1320 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above.
  • the transceiver 1320 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver.
  • the transceiver 1320 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.
  • the wireless device may include a single antenna 1325. However, in some cases the device may have more than one antenna 1325, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.
  • the memory 1330 may include RAM, ROM, or a combination thereof.
  • the memory 1330 may store computer-readable code 1335 including instructions that, when executed by a processor (e.g., the processor 1340) cause the device to perform various functions described herein.
  • a processor e.g., the processor 1340
  • the memory 1330 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.
  • the processor 1340 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) .
  • the processor 1340 may be configured to operate a memory array using a memory controller.
  • a memory controller may be integrated into processor 1340.
  • the processor 1340 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1330) to cause the device 1305 to perform various functions (e.g., functions or tasks supporting channel state information determination and reporting techniques) .
  • the inter-station communications manager 1345 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1345 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 1345 may provide an X2 interface within an LTE/LTE-Awireless communication network technology to provide communication between base stations 105.
  • the code 1335 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications.
  • the code 1335 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1335 may not be directly executable by the processor 1340 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.
  • FIG. 14 shows a flowchart illustrating a method 1400 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the operations of method 1400 may be implemented by a UE 115 or its components as described herein.
  • the operations of method 1400 may be performed by a communications manager as described with reference to FIGs. 6 through 9.
  • a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.
  • the UE may transmit, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE.
  • the operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed by a SRS manager as described with reference to FIGs. 6 through 9.
  • the UE may receive, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal.
  • the operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be performed by a CSI-RS manager as described with reference to FIGs. 6 through 9.
  • the UE may select a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed by a beam selection manager as described with reference to FIGs. 6 through 9.
  • the UE may transmit an indication of the set of beamforming parameters to the base station.
  • the operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be performed by a beam selection manager as described with reference to FIGs. 6 through 9.
  • FIG. 15 shows a flowchart illustrating a method 1500 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the operations of method 1500 may be implemented by a UE 115 or its components as described herein.
  • the operations of method 1500 may be performed by a communications manager as described with reference to FIGs. 6 through 9.
  • a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.
  • the UE may transmit, to a base station, a first reference signal using a subset of a set of available transmission antennas of the UE.
  • the operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed by a SRS manager as described with reference to FIGs. 6 through 9.
  • the UE may receive, from the base station, configuration information that indicates the two or more different channel state information resources within the channel state information resource set.
  • the operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be performed by a CSI resource manager as described with reference to FIGs. 6 through 9. In some cases, the configuration information is received in RRC signaling from the base station.
  • the UE may receive, from the base station, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal.
  • the operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be performed by a CSI-RS manager as described with reference to FIGs. 6 through 9.
  • the UE may select a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be performed by a beam selection manager as described with reference to FIGs. 6 through 9.
  • the UE may format a channel state information report that includes a resource indication that indicates whether the first set of beamforming parameters is determined based on a single channel state information resource within the channel state information resource set or is determined based on multiple different channel state information resources within the channel state information resource set.
  • the operations of 1525 may be performed according to the methods described herein. In some examples, aspects of the operations of 1525 may be performed by a CSI report manager as described with reference to FIGs. 6 through 9.
  • the channel state information report includes a first part that provides a rank indicator, a channel quality indicator, a number of beamforming coefficients reported per layer, and the resource indication.
  • the channel state information report includes a second part that provides a precoding matrix indicator corresponding to the beamforming coefficients reported for each layer and, when the resource indication indicates that multiple different channel state information resources were used to determine the first set of beamforming parameters, an identification of which channel state information resources were selected.
  • the UE may transmit the channel state information report to the base station.
  • the operations of 1530 may be performed according to the methods described herein. In some examples, aspects of the operations of 1530 may be performed by a beam selection manager as described with reference to FIGs. 6 through 9.
  • FIG. 16 shows a flowchart illustrating a method 1600 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the operations of method 1600 may be implemented by a base station 105 or its components as described herein.
  • the operations of method 1600 may be performed by a communications manager as described with reference to FIGs. 10 through 13.
  • a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.
  • the base station may receive, from a UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE.
  • the operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be performed by a SRS manager as described with reference to FIGs. 10 through 13.
  • the base station may transmit, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal.
  • the operations of 1610 may be performed according to the methods described herein. In some examples, aspects of the operations of 1610 may be performed by a CSI-RS manager as described with reference to FIGs. 10 through 13.
  • the base station may receive a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the operations of 1615 may be performed according to the methods described herein. In some examples, aspects of the operations of 1615 may be performed by a beam selection manager as described with reference to FIGs. 10 through 13.
  • FIG. 17 shows a flowchart illustrating a method 1700 that supports channel state information determination and reporting techniques in accordance with aspects of the present disclosure.
  • the operations of method 1700 may be implemented by a base station 105 or its components as described herein.
  • the operations of method 1700 may be performed by a communications manager as described with reference to FIGs. 10 through 13.
  • a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.
  • the base station may receive, from a UE, an indication that a reduced number of transmission antennas are available at the UE.
  • the operations of 1705 may be performed according to the methods described herein. In some examples, aspects of the operations of 1705 may be performed by a CSI resource manager as described with reference to FIGs. 10 through 13.
  • the base station may transmit, to the UE, configuration information that indicates the two or more different channel state information resources within the channel state information resource set.
  • the operations of 1710 may be performed according to the methods described herein. In some examples, aspects of the operations of 1710 may be performed by a CSI resource manager as described with reference to FIGs. 10 through 13.
  • the base station may receive, from the UE, a first reference signal that is transmitted using a subset of a set of available transmission antennas of the UE.
  • the operations of 1715 may be performed according to the methods described herein. In some examples, aspects of the operations of 1715 may be performed by a SRS manager as described with reference to FIGs. 10 through 13.
  • the base station may transmit, to the UE, two or more channel state information reference signals via two or more different channel state information resources within a channel state information resource set, where each of the two or more channel state information reference signals have different beamforming parameters that are based on the first reference signal.
  • the operations of 1720 may be performed according to the methods described herein. In some examples, aspects of the operations of 1720 may be performed by a CSI-RS manager as described with reference to FIGs. 10 through 13.
  • the base station may receive a channel state information report from the UE that includes a first set of beamforming parameters based on measurements of the two or more channel state information reference signals.
  • the operations of 1725 may be performed according to the methods described herein. In some examples, aspects of the operations of 1725 may be performed by a beam selection manager as described with reference to FIGs. 10 through 13.
  • 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
  • a CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc.
  • CDMA2000 covers IS-2000, IS-95, and IS-856 standards.
  • IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc.
  • IS-856 TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc.
  • UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA.
  • a TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) .
  • GSM Global System for Mobile Communications
  • An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, etc.
  • UMB Ultra Mobile Broadband
  • E-UTRA Evolved UTRA
  • IEEE Institute of Electrical and Electronics Engineers
  • Wi-Fi Institute of Electrical and Electronics Engineers
  • IEEE 802.16 WiMAX
  • IEEE 802.20 Flash-OFDM
  • UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS) .
  • LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA.
  • UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from the organization named “3rd Generation Partnership Project” (3GP
  • CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) .
  • 3GPP2 3rd Generation Partnership Project 2
  • the techniques described herein may be used for the systems and radio technologies mentioned herein as well as other systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.
  • a macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider.
  • a small cell may be associated with a lower-powered base station, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed, etc. ) frequency bands as macro cells.
  • Small cells may include pico cells, femto cells, and micro cells according to various examples.
  • a pico cell for example, may cover a small geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider.
  • a femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG) , UEs for users in the home, and the like) .
  • An eNB for a macro cell may be referred to as a macro eNB.
  • An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB.
  • An eNB may support one or multiple (e.g., two, three, four, and the like) cells, and may also support communications using one or multiple component carriers.
  • the wireless communications systems described herein may support synchronous or asynchronous operation.
  • the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time.
  • the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time.
  • the techniques described herein may be used for either synchronous or asynchronous operations.
  • Information and signals described herein may be represented using any of a variety of different technologies and techniques.
  • data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
  • a general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine.
  • a processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .
  • the functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.
  • Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another.
  • a non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer.
  • non-transitory computer-readable media may include random-access memory (RAM) , read-only memory (ROM) , electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.
  • RAM random-access memory
  • ROM read-only memory
  • EEPROM electrically erasable programmable ROM
  • flash memory compact disk (CD) ROM or other optical disk storage
  • magnetic disk storage or other magnetic storage devices
  • any connection is properly termed a computer-readable medium.
  • the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave
  • the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium.
  • Disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

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  • Signal Processing (AREA)
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  • Mathematical Physics (AREA)
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Abstract

L'invention concerne des procédés, des systèmes et des dispositifs pour des communications sans fil prenant en charge des techniques de détermination et de signalement d'informations d'état de canal (CSI). Un ensemble de ressources CSI peut être configuré par une station de base pour inclure deux ressources CSI ou plus pour un UE. L'UE peut mesurer deux signaux de référence CSI (CSI-RS) ou plus dans les ressources CSI, et effectuer une sélection de faisceau sur les deux ressources CSI ou plus. Si l'UE sélectionne deux faisceaux ou plus pour des communications avec la station de base qui se trouvent dans différentes ressources CSI, l'UE peut fournir une indication des faisceaux sélectionnés. Si l'UE sélectionne un faisceau pour des communications dans une ressource CSI, l'UE peut fournir une indication de l'indice de ressource et de la sélection de port associées à la ressource CSI.
PCT/CN2019/104623 2019-09-06 2019-09-06 Techniques de détermination et de signalement d'informations d'état de canal WO2021042349A1 (fr)

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WO2023280043A1 (fr) * 2021-07-05 2023-01-12 维沃移动通信有限公司 Procédé de notification de faisceaux et terminal
WO2023023965A1 (fr) * 2021-08-25 2023-03-02 Qualcomm Incorporated Métriques spécifiques au faisceau dans des rapports pour transmission de liaison montante

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Publication number Priority date Publication date Assignee Title
WO2022206305A1 (fr) * 2021-04-02 2022-10-06 大唐移动通信设备有限公司 Procédé de transmission améliorée de signal csi-rs, procédé et appareil d'émission d'informations de retour, dispositif et support
WO2023280043A1 (fr) * 2021-07-05 2023-01-12 维沃移动通信有限公司 Procédé de notification de faisceaux et terminal
WO2023023965A1 (fr) * 2021-08-25 2023-03-02 Qualcomm Incorporated Métriques spécifiques au faisceau dans des rapports pour transmission de liaison montante

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