Patent Description:
<NUM> NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (such as, with Internet of Things (IoT)), and other requirements.

Wireless communication devices including base stations and user equipment (UE) may measure signals and provide information regarding channel quality. For example, a base station may transmit a channel state information reference signal (CSI-RS) to the UE, and the UE may respond with information determined based on the CSI-RS. Aspects presented herein enable the UE to provide channel state information in a more efficient manner, such as for frequency division duplex (FDD) communication with relatively small duplex separation. The improvements described herein may be applicable to <NUM> NR and may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

<CIT> falls within the terms of Art. <NUM>(<NUM>) EPC and discusses a UE that transmits one or more uplink reference signals that indicate a first precoding matrix associated with a transmission rank and a channel quality calculated based at least in part on a received set of downlink reference signals. <CIT> falls within the terms of Art. <NUM>(<NUM>) EPC and discloses a method of precoding SRS to indicate the selected PMI at the UE. 3GPP document R1-<NUM> "Discussion on reciprocity based CSI acquisition mechanism" by Huawei; HiSilicon discloses partial CSI feedback for gNB to acquire full CSI. 3GPP discussion document R1-<NUM> "SRS capacity enhancements" by Qualcomm Inc. discusses sounding reference signal (SRS) capacity enhancements for supporting channel reciprocity-based full dimensional multiple-input multiple-output (FD-MIMO).

A base station may transmit a channel state information reference signal (CSI-RS) that is used by a user equipment (UE) to estimate a channel and report channel quality information back to the base station. The reported information may be referred to as channel state information feedback (CSF). The UE may report the CSF, such as a channel quality indicator (CQI), a rank indicator (RI), and a precoding matrix indicator (PMI), based on the measured CSI-RS resources.

A UE may experience similar scattering and rank distribution for uplink and downlink communication for frequency division duplex (FDD) communication with a relatively small duplex separation. Aspects presented herein improve CSF for FDD communication and enable the UE to further provide dissimilarity information about multiple, associated CSI-RS through a precoded SRS.

To the accomplishment of the foregoing and related ends, the one or more aspects include the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail some illustrative features of the one or more aspects.

However, it will be apparent to those having ordinary skill in the art that these concepts may be practiced without these specific details. In some instances, structures and components are shown in block diagram form in order to avoid obscuring such concepts.

These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, among others (collectively referred to as "elements").

Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, among others, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more examples, the functions described may be implemented in hardware, software, or any combination thereof. By way of example, and not limitation, such computer-readable media can include a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

A base station may transmit a channel state information (CSI) reference signal (CSI-RS) that is used by a user equipment (UE) to perform measurements, to estimate a channel based on the measurements, and report channel quality information back to the base station based on the channel estimation. The reported information may be referred to as channel state information feedback (CSF). The UE may report the CSF including, for example, a channel quality indicator (CQI), a rank indicator (RI), and a precoding matrix indicator (PMI), based on the measured CSI-RS resources.

The UE may experience similar scattering and rank distribution for uplink and downlink communications for frequency division duplex (FDD) communications with a relatively small duplex separation. Aspects presented herein improve CSF for FDD communication and enable the UE to further provide dissimilarity information about multiple, associated CSI-RS through a precoded SRS.

As presented herein, a base station may transmit a first CSI-RS on a first set of beams and a second CSI-RS on a second set of beams. A UE may determine a CQI, an RI, and a PMI based on the first CSI-RS and report the CSI and RI to the base station. The UE may indicate the PMI to the base station using a precoded sounding reference signal (SRS). For example, the UE may determine a dissimilarity between the first CSI-RS and the second CSI-RS and may further indicate the dissimilarity to the base station based on the precoding of the SRS. The base station may use the CQI, the RI, the PMI, and the dissimilarity between the two CSI-RS to improve communication with the UE.

<FIG> is a diagram illustrating an example of a wireless communications system and an access network <NUM> in accordance with aspects presented herein. As illustrated in <FIG>, a base station <NUM> or <NUM> may exchange wireless communication with one or more UEs <NUM>. The communication may be exchanged using beams <NUM>.

The UE <NUM> in the access network may receive a first CSI-RS on a first set of beams from the base station <NUM> or <NUM> and may receive a second CSI-RS on a second set of beams from the base station <NUM> or <NUM>. The UE <NUM> may include a CSF component <NUM> configured to determine a CQI, an RI, and a PMI based on the first CSI-RS. The CSF component <NUM> may be further configured to report the CQI and the RI using an uplink control channel and to indicate the PMI using a precoded SRS transmission. The precoded SRS transmission may be precoded based on a dissimilarity that the UE <NUM> determines between the first CSI-RS and the second CSI-RS. The base station <NUM> or <NUM> may transmit the first CSI-RS based on a default precoder and may transmit the second CSI-RS based on a non-precoded SRS received from the UE <NUM>. The base station <NUM> or <NUM> may include a CSF component <NUM> configured to receive a report of CQI and RI based on the first CSI-RS in an uplink control channel from a UE and to determine a PMI based on a precoded SRS received from the UE.

The wireless communications system (also referred to as a wireless wide area network (WWAN)) includes base stations <NUM>, UEs <NUM>, an Evolved Packet Core (EPC) <NUM>, and another core network <NUM> (such as, a <NUM> Core (5GC)). The base stations <NUM> may include macrocells (high power cellular base station) or small cells (low power cellular base station).

The base stations <NUM> configured for <NUM> LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC <NUM> through backhaul links <NUM> (such as, S1 interface). The base stations <NUM> configured for <NUM> NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with core network <NUM> through backhaul links <NUM>. In addition to other functions, the base stations <NUM> may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (such as, handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations <NUM> may communicate directly or indirectly (such as, through the EPC <NUM> or core network <NUM>) with each other over backhaul links <NUM> (such as, an X2 interface).

The communication links <NUM> between the base stations <NUM> and the UEs <NUM> may include uplink (UL) (also referred to as reverse link) transmissions from a UE <NUM> to a base station <NUM> or downlink (DL) (also referred to as forward link) transmissions from a base station <NUM> to a UE <NUM>. The communication links <NUM> may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, or transmit diversity. The base stations <NUM> / UEs <NUM> may use spectrum up to Y MHz (for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, among others) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. Allocation of carriers may be asymmetric with respect to DL and UL (for example, more or fewer carriers may be allocated for DL than for UL).

Some UEs <NUM> may communicate with each other using device-to-device (D2D) communication link <NUM>.

The small cell <NUM>' may operate in a licensed or an unlicensed frequency spectrum. The small cell <NUM>', employing NR in an unlicensed frequency spectrum, may boost coverage to or increase capacity of the access network.

A base station <NUM>, whether a small cell <NUM>' or a large cell (such as, a macro base station), may include an eNB, gNodeB (gNB), or another type of base station. Some base stations, such as gNB <NUM> may operate in a traditional sub <NUM> spectrum, in millimeter wave (mmW) frequencies, or near mmW frequencies in communication with the UE <NUM>. Communications using the mmW / near mmW radio frequency band (such as, <NUM> - <NUM>) has extremely high path loss and a short range. The mmW base station <NUM> may utilize beamforming (such as beams <NUM>) with the UE <NUM> to compensate for the extremely high path loss and short range.

The base station <NUM> may transmit a beamformed signal to the UE <NUM> in one or more transmit directions (such as the beams <NUM>). The UE <NUM> may receive the beamformed signal from the base station <NUM> in one or more receive directions (such as beams <NUM>).

The IP Services <NUM> may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, or other IP services.

The IP Services <NUM> may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, or other IP services.

Examples of UEs <NUM> include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (such as, an MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs <NUM> may be referred to as IoT devices (such as, a parking meter, a gas pump, a toaster, a vehicle, a heart monitor, among others).

<FIG> are diagrams illustrating examples of a first NR frame, downlink channels within an NR subframe, a second NR frame, and uplink channels within an NR subframe, respectively. The description applies also to a <NUM>/NR frame structure that is TDD.

Other wireless communication technologies may have a different frame structure or different channels. The subcarrier spacing is <NUM> and symbol duration is approximately <NUM>.

The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), or UCI.

<FIG> is a diagram illustrating an example of a base station <NUM> and UE <NUM> in an access network. The controller/processor <NUM> provides RRC layer functionality associated with broadcasting of system information (such as MIB, SIBs), RRC connection control (such as RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The TX processor <NUM> handles mapping to signal constellations based on various modulation schemes (such as binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (for example a pilot) in the time or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The channel estimate may be derived from a reference signal or channel condition feedback transmitted by the UE <NUM>.

The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal.

The controller/processor <NUM> is also responsible for error detection using an ACK or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the base station <NUM>, the controller/processor <NUM> provides RRC layer functionality associated with system information (such as MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression / decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The controller/processor <NUM> is also responsible for error detection using an ACK or NACK protocol to support HARQ operations.

At least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM> may be configured to perform aspects in connection with the CSF component <NUM> in <FIG>.

CSI-RS is a downlink signal transmitted by a base station. A UE receives the CSI-RS and uses the CSI-RS to estimate a channel and report channel quality information back to the base station. The base station may configure a CSI resource configuration for the UE that indicates a type of the CSI-RS reference signals that are transmitted by the base station for measurement by the UE. For example, the type of reference signal may include a non-zero power (NZP) CSI-RS resource or a channel state information interference measurement (CSI-IM) resource. The base station may configure the CSI resource configuration with an indication of a type of the resources, such as a periodic, aperiodic, or semi-persistent type of CSI resource. The CSI report configuration may indicate to the UE the CSI resource configuration(s) that are to be used for the CSI measurements by the UE.

<FIG> illustrates an example communication flow <NUM> for CSF between a UE <NUM> and a base station <NUM> in accordance with aspects presented herein. The base station <NUM> transmits multiple CSI-RS resources at <NUM>, for example, CSI-RS resource <NUM>, CSI-RS resource <NUM>, CSI-RS resource <NUM>, and so forth. The base station <NUM> may transmit each CSI-RS using a set of beams. The base station may use a set of beams the includes a single beam or multiple beams. As illustrated at <NUM>, the UE <NUM> receives and measures each of the CSI-RS resources, for example, CSI-RS resource <NUM>, CSI-RS resource <NUM>, and CSI-RS resource <NUM>. The UE <NUM> determines, or calculates, the CSI to report to the base station <NUM>. The CSI may include a CQI or a PMI that the UE <NUM> determines based on the measured CSI-RS resources. Then, at <NUM>, the UE <NUM> reports the CQI or PMI to the base station using a selected CSI-RS resource. The report may be referred to as a CSF report. The UE <NUM> may transmit the CSF report on a PUCCH or a PUSCH.

Aspects presented herein improve the CSF process or report by adjusting the manner in which a base station transmits CSI-RS or the manner in which the UE provides the CSF.

For frequency division duplex (FDD) communication, uplink and downlink bands may be located on different frequencies. Wireless communication with a bandwidth part may be performed within a limited frequency spectrum. For FDD communication with a relatively small duplex separation, such as less than <NUM> or <NUM>, the UE may experience similar scattering and a similar rank distribution for uplink and downlink communication with the base station. Scattering occurs when a size of an obstacle for a wireless signal is smaller than a wavelength of the radio wave. If the frequency separation for an uplink band and a downlink band is relatively small, such as less than <NUM> or less than <NUM>, then the same obstacles may lead to scattering for both downlink and uplink signals. As well, multipath radio waves due to scatters may achieve a higher rank. If the downlink and the uplink signals experience similar scatters, then a similar rank distribution may apply, as well. Aspects presented herein improve the efficiency of the CSF process and enable the UE to provide dissimilarity information to the base station.

<FIG> illustrates an example communication flow <NUM> for CSF between a UE <NUM> and a base station <NUM> in accordance with aspects presented herein. The base station may jointly transmit, at <NUM>, two sets of CSI-RS resources using different precoders. For example, the base station <NUM> may precode a CSI-RS resource <NUM> with a default precoder and may precode a second CSI-RS resource <NUM> with a different precoder, such as based on measurements about the UE <NUM>. For example, the UE <NUM> may transmit a non-precoded SRS, at <NUM>. The SRS is an uplink signal transmitted by the UE <NUM> to help the base station <NUM> obtain the CSI. The CSI may provide information about how the signal from the base station <NUM> propagates from the UE <NUM> to the base station <NUM>. The SRS may represent effects on the signal, such as due to scattering, fading, power decay with distance, among other examples The base station <NUM> may perform an uplink channel estimation for the non-precoded SRS and use the uplink channel estimation to determine the precoder for CSI-RS resource <NUM>.

Thus, one set of CSI-RS, for example CSI-RS resource <NUM>, may be transmitted with a defined precoder B, <MAT>. In this example, SVD may correspond to Singular Value Decomposition, HDL corresponds to the downlink channel, UDL corresponds to left singular vectors of HDLB _, DDL corresponds to singular values of HDLB , and <MAT> corresponds to right singular vectors of HDLB which can be regarded as a PMI for the downlink channel. The other set of CSI-RS may be transmitted with a precoder BUUL where UUL is <MAT>. H̃UL is the estimated UL channel from non - precoded SRS, transmitted at <NUM>, and <MAT>. UUL corresponds to left singular vectors of BHH̃UL, DUL corresponds to singular values of BHH̃UL, and <MAT> corresponds to right singular vectors of BHH̃UL. ÜUL corresponds to left singular vectors of H̃UL, D̈UL corresponds to singular values of H̃UL, and <MAT> corresponds to a PMI for the right singular vectors of H̃UL.

The UE <NUM> may measure the first set of CSI-RS (for example, CSI-RS resource <NUM>) and may use the first set of CSI-RS to calculate information such as CQI, RI, or PMI (for example, <MAT>), as illustrated at <NUM>. At <NUM>, the UE <NUM> may measure the dissimilarity (T) between the two CSI-RS resources (for example, between CSI-RS resource <NUM> and CSI-RS resource <NUM>). For example, the UE <NUM> may derive ŨUL = (HDLB)†(HDLBUUL) based on the measurement of two sets of CSI-RS and generate <MAT>. ŨUL corresponds to estimated left singular vectors of BHH̃UL, and (. )† is a pseudo-inverse operation. The UE <NUM> may measure the precoder dissimilarity from (HDLBUUL), for example, the UE <NUM> may derive <MAT> according to <MAT>.

The UE <NUM> may send an analog PMI, for example, VDL, in the form of an SRS precoded by T. Thus, at <NUM>, the UE <NUM> may transmit a precoded SRS that is precoded based on the dissimilarity T determined between the CSI-RS resource precoded with a default precoder and the CSI-RS resources precoded based on the uplink channel estimated of the UE's non-precoded SRS. The UE may report the CQI and the RI on a PUCCH at <NUM>. Thus, the base station <NUM> may determine the CQI and the RI from the received PUCCH and may determine the PMI from the precoded SRS received from the UE <NUM>. The base station <NUM> may derive T̃ = (H̃UL)†(H̃ULT), where T̃ corresponds to estimated precoder of received SRS. The base station <NUM> can then derive the PMI, for example, <MAT>. As another example, the base station <NUM> may first derive an intermediate variable that can be used to derive the final precoder <MAT> based on received precoded SRS, for example, <MAT>. Then, the base station <NUM> can derive <MAT>. Thus, the UE <NUM> may convey PMI, <MAT>, to the base station <NUM> by the SRS through analog feedback. Thus, aspects presented herein provide for an analog CSF for FDD partial reciprocity.

Aspects presented herein may further improve the manner in which CSI-RS resources are configured. Each report setting for CSI-RS may be associated with a single downlink BWP and may contain the parameters to indicate that the report setting is for FDD analog CSF. Each CSI resource setting may be linked to the report setting for channel measurement (for FDD analog CSF) may configure at least two CSI-RS resources. For each CSI reporting setting, multiple resource settings (<NUM>, <NUM> or <NUM>) may be configured. For CSI acquisition, there may be <NUM> or <NUM> resource settings. One resource may be configured for channel measurement and one or two resources may be configured for interference measurement. Aspects presented herein may involve the resource configuration for channel measurement. The manner in which the CSI-RS resources are configured for channel measurement may depend on the resource setting for interference measurement.

For an aperiodic CSI-RS resource setting, if the interference measurement is performed on NZP CSI-RS or CSI-IM, each CSI resource setting may contain a configuration of a list of S=<NUM> CSI-RS resource sets, each of the two resource sets being configured with one CSI-RS resource. If the interference measurement is performed on NZP CSI-RS or CSI-IM, each CSI-RS resource setting may contain a configuration that is limited to S=<NUM> (for example, a single CSI-RS resource set). Aperiodic resource sets may be associated with a trigger state. The base station <NUM> may configure a bitmap for the UE <NUM>, such as in RRC signalling. In the bitmap, a bitwidth Nbit may equal a number of resource sets in a resource setting. A number of one(s) in the bitmap None may be equal to <NUM>/<NUM>, <NUM> or <NUM> for FDD analog CSF.

For a periodic or semi-persistent CSI resource setting, the number of configured CSI-RS resource sets may be limited to S=<NUM> (for example, a single CSI-RS resource set). This single CSI-RS resource set may be configured with two CSI-RS resources. Alternately, the CSI-RS resource sets may be based on S=<NUM> each with a single CSI-RS resource.

The UE <NUM> may receive or infer additional information regarding the two CSI-RS resources for channel measurement. For example, the two configured CSI-RS resources for channel measurement may be associated. One of the CSI-RS resources (for example, CSI-RS resource <NUM>) may be a primary CSI-RS resource. The UE <NUM> may calculate CQI/RI and PMI conditioned on the primary CSI-RS resource. The other CSI-RS resource (for example, CSI-RS resource <NUM>) may be a subsidiary CSI-RS resource that is used by the UE <NUM> for determining a dissimilarity measurement. The dissimilarity measurement may include a spatial domain transmission filter T calculation that may be used by the UE <NUM> for conveying PMI through a target SRS resource, such as by precoding the SRS based on the measured dissimilarity between the two CSI-RS.

The base station <NUM> may explicitly indicate the primary CSI-RS resource or the subsidiary CSI-RS resource to the UE <NUM>. The explicit indication may be included in configuration information for the primary CSI-RS or the subsidiary CSI-RS resource, such as illustrated at <NUM>. In another example, the UE <NUM> may determine the primary CSI-RS resource or the subsidiary CSI-RS resource based on implicit information from the base station <NUM>. The implicit indication may be included in configuration information for the primary CSI-RS or the subsidiary CSI-RS resource, for example, as illustrated at <NUM>. For example, the primary CSI-RS resource may have the corresponding report quantity configurations configured (such as CQI, RI, PMI), whereas the subsidiary CSI-RS resource may have the report quantities configured as "none". The UE <NUM> may identify the primary CSI-RS resource and the subsidiary CSI-RS resource based on whether or not the corresponding report quantity configuration are configured. The UE <NUM> may also identify the primary CSI-RS resource or the subsidiary CSI-RS resource based on other implicit information.

In addition to identifying which CSI-RS resource is the primary CSI-RS resource and which is the subsidiary CSI-RS resource, the UE <NUM> may also determine an association between the CSI-RS resource and the subsidiary CSI-RS resource. The association between the CSI-RS resources may be configured in the configuration of the primary CSI-RS resource or in the configuration of the subsidiary CSI-RS resource, for example as illustrated at <NUM>.

The UE <NUM> may identify the SRS resource to use to indicate the PMI to the base station. The UE <NUM> may receive information from the base station that is used to determine an association between the SRS resource for sending analog PMI and the subsidiary CSI-RS resource. For example, the association between the subsidiary CSI-RS resource and the SRS resource for sending the precoded SRS may be configured in either subsidiary CSI-RS resource configuration or the SRS resource configuration, for example, as illustrated at <NUM>.

<FIG> is a flowchart <NUM> of a method of wireless communication including CSF in accordance with aspects presented herein. method may be performed by a UE or a component of a UE (such as the UE <NUM>, <NUM>, <NUM>; the apparatus <NUM>, which may include the memory <NUM> and which may be an entire UE <NUM> or a component of the UE <NUM>, such as the TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM>). Optional aspects are illustrated with a dashed line. The method may improve the manner in which a UE measures and provides CSF.

At <NUM>, the UE receives a first CSI-RS on a first set of beams. The first set of beams may include multiple beams. The first set of beams may include a single beam. The first CSI-RS may correspond to CSI resource <NUM> in <FIG>. For example, first CSI-RS component <NUM> of the apparatus <NUM> may receive the first CSI-RS.

At <NUM>, the UE receives a second CSI-RS on a second set of beams. The second set of beams may include multiple beams. The second set of beams may include a single beam. The second CSI-RS may correspond to CSI resource <NUM> in <FIG>. For example, second CSI-RS component <NUM> of the apparatus <NUM> may receive the second CSI-RS.

At <NUM>, the UE determines a CQI, a RI, and a PMI based on the first CSI-RS. The UE may determine additional CSI based on the first CSI-RS. For example, the UE may determine at least one of the CQI, RI, and PMI on the first CSI-RS and not on the second CSI-RS. For example, CSI component <NUM> of the apparatus <NUM> may determine the CQI, RI, and PMI based on the first CSI-RS.

At <NUM>, the UE transmits a report the CQI and the RI. The CQI and RI may be reported to the base station via an uplink control channel. For example, the report component <NUM> of the apparatus <NUM> may report the CQI and RI determined by the CQI component <NUM> based on the first CSI-RS.

At <NUM>, the UE transmits a precoded SRS transmission that indicates the PMI. Thus, the PMI is reported separately from the CQI and RI and is reported in a different manner than the CQI and RI. For example, SRS component <NUM> or precode component <NUM> of the apparatus <NUM> may indicate the PMI using a precoded SRS. As illustrated at <NUM>, the UE determines a dissimilarity between the first CSI-RS and the second CSI-RS. The dissimilarity may be determined, such as described in connection with <NUM> in <FIG>. For example, dissimilarity component <NUM> of the apparatus <NUM> may determine the dissimilarity between the first and second CSI-RS. The UE then precodes an SRS transmission to generate the precoded SRS transmission based on the dissimilarity determined between the first CSI-RS and the second CSI-RS to indicate the PMI. For example, precode component <NUM> of the apparatus <NUM> may precode the SRS. As described in connection with <NUM> and <NUM>, the SRS may indicate an FDD analog PMI through its decoding based on T.

The UE transmits a non-precoded SRS prior to receiving the first CSI-RS and the second CSI-RS. For example, SRS component <NUM> of the apparatus <NUM> may transmit the unprecoded SRS. The first CSI-RS, received at <NUM>, is associated with a defined precoder, for example, may be precoded by defined precoder B. The second CSI-RS is associated with a precoder based at least in part on an uplink channel estimate of the non-precoded SRS that is transmitted by the UE.

A reporting setting configured for the UE may include a parameter indicating that the report setting is for FDD analog CSF. The UE may receive an indication regarding the type of CSI-RS. For example, the UE may receive an indication of aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS that are associated with a trigger state. The indication may be received by the resource set component <NUM>, and provided to the first CSI-RS component <NUM> and the second CSI-RS component <NUM>. The aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS may be indicated in a bitmap received in an RRC message. If interference measurement is performed on NZP CSI-RS signals or on CSI-IM, each CSI resource setting for channel measurement may include two CSI-RS resource sets, and each of the two CSI-RS resource sets may be configured with a single CSI-RS resource. For example, the UE may further perform the interference measurement based on the on NZP CSI-RS signals or on CSI-IM, each CSI resource setting for channel measurement including two CSI-RS resource sets. The UE may receive a configuration of each of the two CSI-RS resource sets with a single CSI-RS resource. If interference measurement is performed on NZP CSI-RS or CSI-IM signals, each CSI resource setting for channel measurement may include a single CSI-RS resource set configured with two CSI-RS resources. For example, the UE may further perform the interference measurement based on NZP CSI-RS or CSI-IM signals, each CSI resource setting for channel measurement including a single CSI-RS resource set configured with two CSI-RS resources. The UE may receive a configuration of the two CSI-RS resources, each CSI-RS resource including two CSI-RS resources.

The UE may receive an indication of a single periodic or semi-persistent CSI-RS resource set for the first CSI-RS and the second CSI-RS, where the single periodic or semi-persistent CSI-RS resource set is configured with two CSI-RS resources. The indication may be received by the resource set component <NUM>, and provided to the first CSI-RS component <NUM> and the second CSI-RS component <NUM>.

The two CSI-RS resources may include a primary CSI-RS resource and a subsidiary or secondary CSI-RS resource. For example, the first CSI-RS may include a primary CSI-RS resource that is used by the UE for determining the CQI, the RI, and the PMI. The second CSI-RS may include a subsidiary CSI-RS resource for determining a dissimilarity between the first CSI-RS and the second CSI-RS, such as at <NUM>. The UE may receive an indication that the first CSI-RS is the primary CSI-RS resource or that the second CSI-RS is the subsidiary CSI-RS resource. The UE may receive an explicit indication of the primary/subsidiary CSI-RS resource(s). Alternatively or additionally, the UE may receive an implicit indication of the primary/subsidiary CSI-RS resource(s). The indication, whether explicit or implicit, may be received by the resource set component <NUM>, and provided to the first CSI-RS component <NUM> and the second CSI-RS component <NUM>. For example, the UE may determine that the first CSI-RS includes the primary CSI-RS resource based on a configuration of a report quantity for the CQI, the RI, and the PMI for the first CSI-RS. The UE may determine that the second CSI-RS includes the subsidiary CSI-RS resource based on a report quantity for the CQI, the RI, and the PMI not being configured for the second CSI-RS, such as being configured as "none.

The UE may receive an indication of an association between the primary CSI-RS resource and the subsidiary CSI-RS resource, where the association indication is received in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The indication of an association may be received by the association component <NUM> of the apparatus <NUM>. The UE may receive an indication of an association between the subsidiary CSI-RS resource and an SRS resource for the precoded SRS transmission, where the indication is received in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The UE may determine the SRS resource for transmitting the precoded SRS, at <NUM>, based on the indication of the association between the CSI-RS resource(s) and the SRS resource.

Various aspects of the flowchart <NUM> may be performed in a different order than the visual depiction of <FIG>.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an example apparatus <NUM> that supports CSF in accordance with aspects presented herein. The software, when executed by the cellular baseband processor <NUM>, causes the cellular baseband processor <NUM> to perform the various functions described herein. In one configuration, the apparatus <NUM> may be a modem chip and include just the baseband processor <NUM>, and in another configuration, the apparatus <NUM> may be the entire UE (for example, see <NUM> of <FIG>) and include the additional modules of the apparatus <NUM>.

The communication manager <NUM> includes a first CSI-RS component <NUM> configured to receive a first CSI-RS on a first set of beams. The communication manager <NUM> includes a second CSI-RS component <NUM> configured to receive a second CSI-RS on a second set of beams. The communication manager <NUM> includes a CSI component <NUM> configured to determine a CQI, an RI, and a PMI based on the first CSI-RS. The communication manager <NUM> includes a report component <NUM> configured to report the CQI and RI using an uplink control channel. The communication manager <NUM> includes an SRS component <NUM> or precode component <NUM> configured to indicate the PMI using a precoded SRS transmission. The communication manager <NUM> includes a dissimilarity component <NUM> configured to determine a dissimilarity between the first CSI-RS and the second CSI-RS. The apparatus includes a precode component <NUM> configured to precode a SRS transmission to generate the precoded SRS transmission based on the dissimilarity determined between the first CSI-RS and the second CSI-RS to indicate the PMI. The communication manager <NUM> includes an SRS component <NUM> configured to transmit a non-precoded SRS prior to receiving the first CSI-RS and the second CSI-RS. The communication manager <NUM> may include a resource set component <NUM> configured to receive information about resource set(s) for the first and second CSI-RS. For example, resource set component <NUM> may be configured to receive an indication of aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS that are associated with a trigger state. The resource set component <NUM> may be configured to receive an indication of a single periodic or semi-persistent CSI-RS resource set for the first CSI-RS and the second CSI-RS, where the single periodic or semi-persistent CSI-RS resource set is configured with two CSI-RS resources. The resource set component <NUM> may be configured to receive an indication for at least one of the first CSI-RS as the primary CSI-RS resource or the second CSI-RS as the subsidiary CSI-RS resource. The communication manager <NUM> may include association component <NUM> configured to receive an association regarding the CSI-RS resource(s) or the SRS resource. For example, the association component <NUM> may be configured to receive an indication that indicates an association between the primary CSI-RS resource and the subsidiary CSI-RS resource, where the association indication is received in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The association component <NUM> may be configured to receive an indication of an association between the subsidiary CSI-RS resource and an SRS resource for the precoded SRS transmission, where the indication is received in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource.

The apparatus <NUM> may include additional components that perform each of the blocks of the algorithm in the aforementioned flowcharts of <FIG> and <FIG>.

In one configuration, the apparatus <NUM>, and in particular, the cellular baseband processor <NUM>, includes means for receiving a first CSI-RS on a first set of beams and means for receiving a second CSI-RS on a second set of beams. The apparatus <NUM> includes means for determining a CQI, an RI, and a PMI based on the first CSI-RS. The apparatus <NUM> includes means for reporting the CQI and RI using an uplink control channel. The apparatus <NUM> includes means for indicating the PMI using a precoded SRS transmission. The apparatus <NUM> includes means for determining a dissimilarity between the first CSI-RS and the second CSI-RS. The apparatus <NUM> may include means for precoding a SRS transmission to generate the precoded SRS transmission based on the dissimilarity determined between the first CSI-RS and the second CSI-RS to indicate the PMI. The apparatus <NUM> may include means for transmitting a non-precoded SRS prior to receiving the first CSI-RS and the second CSI-RS. The apparatus <NUM> may include means for receiving an indication of aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS that are associated with a trigger state. The apparatus <NUM> may include means for receiving an indication of a single periodic or semi-persistent CSI-RS resource set for the first CSI-RS and the second CSI-RS, where the single periodic or semi-persistent CSI-RS resource set is configured with two CSI-RS resources. The apparatus <NUM> may include means for receiving an indication for at least one of the first CSI-RS as the primary CSI-RS resource or the second CSI-RS as the subsidiary CSI-RS resource. The apparatus <NUM> may include means for receiving an association indication that indicates an association between the primary CSI-RS resource and the subsidiary CSI-RS resource, where the association indication is received in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The apparatus <NUM> may include means for receiving an indication of an association between the subsidiary CSI-RS resource and an SRS resource for the precoded SRS transmission, where the indication is received in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The means may be one or more of the aforementioned components of the apparatus <NUM> configured to perform the functions recited by the aforementioned means. As described herein, the processing system <NUM> may include the TX Processor <NUM>, the RX Processor <NUM>, and the controller/processor <NUM>.

<FIG> is a flowchart <NUM> of a method of wireless communication including CSF in accordance with aspects presented herein. The method may be performed by a base station or a component of a base station (such as the base station <NUM>, <NUM>, <NUM>, <NUM>; the apparatus <NUM>, which may include the memory <NUM> and which may be the entire base station <NUM> or a component of the base station <NUM>, such as the TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM>). The method may improve the manner in which a base station transmits CSI-RS and receives CSF.

At <NUM>, the base station transmits a first CSI-RS on a first set of beams. The first set of beams may include multiple beams. The first set of beams may include a single beam. The first CSI-RS may correspond to CSI resource <NUM> in <FIG>. For example, first CSI-RS component <NUM> of apparatus <NUM> may transmit the first CSI-RS.

At <NUM>, the base station transmits a second CSI-RS on a second set of beams. The second set of beams may include multiple beams. The second set of beams may include a single beam. The second CSI-RS may correspond to CSI resource <NUM> in <FIG>. For example, second CSI-RS component <NUM> of apparatus <NUM> may transmit the second CSI-RS.

At <NUM>, the base station may receive an uplink control channel from a UE that includes a report of the CQI and RI. The CQI and RI may be measured by the UE based on the first CSI-RS. For example, report component <NUM> of apparatus <NUM> may receive report the CQI and RI determined based on the first CSI-RS.

At <NUM>, the base station may receive a precoded SRS from the UE. At <NUM>, the base station may determine a PMI for the UE based on the precoded SRS from the UE. Thus, the PMI may be received separately from the CQI and RI and may be received in a different manner than the CQI and RI. For example, SRS component <NUM> or PMI component <NUM> of apparatus <NUM> may determine the PMI based on a precoded SRS. As described in connection with <NUM> and <NUM>, the SRS may be precoded based on a dissimilarity measured at the UE between the first CSI-RS and the second CSI-RS. As described in connection with <NUM> and <NUM>, the SRS may indicate an FDD analog PMI through its decoding based on T.

The base station may a non-precoded SRS prior to transmitting the first CSI-RS and the second CSI-RS. For example, SRS component <NUM> of apparatus <NUM> may receive the unprecoded SRS. The first CSI-RS, transmitted at <NUM>, may include a defined precoder, for example, may be precoded by defined precoder B. The second CSI-RS may include a precoder based at least in part on an uplink channel estimate of the non-precoded SRS that is determined by the base station.

A reporting setting configured for the UE may include a parameter indicating that the report setting is for FDD analog CSF. The base station may transmit an indication regarding the type of CSI-RS. For example, the base station may transmit an indication of aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS that are associated with a trigger state. The indication may be transmitted by resource set component <NUM>. The aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS may be indicated in a bitmap received in an RRC message. If interference measurement is performed on NZP CSI-RS signals or CSI-IM signals, each CSI resource setting for channel measurement may include two CSI-RS resource sets, and each of the two CSI-RS resource sets may be configured with a single CSI-RS resource. For example, the base station may configure two CSI-RS resource sets each having a single CSI-RS resource for the interference measurement to be performed on NZP CSI-RS signals or CSI-IM signals, each CSI resource setting for channel measurement may include two CSI-RS resource sets. If interference measurement is performed on NZP CSI-RS signals or CSI-IM signals, each CSI resource setting for channel measurement may include a single CSI-RS resource set configured with two CSI-RS resources. For example, the base station may configure a single CSI-RS resource set with two CSI-RS resources for the interference measurement to be performed on the NZP CSI-RS signals or CSI-IM signals.

The base station may transmit an indication of a single periodic or semi-persistent CSI-RS resource set for the first CSI-RS and the second CSI-RS, where the single periodic or semi-persistent CSI-RS resource set is configured with two CSI-RS resources. The indication may be transmitted by resource set component <NUM>.

The two CSI-RS resources may include a primary CSI-RS resource and a subsidiary or secondary CSI-RS resource. For example, the first CSI-RS may include a primary CSI-RS resource that is to be used by the UE for determining the CQI, the RI, and the PMI. The second CSI-RS may include a subsidiary CSI-RS resource to be used by the UE for determining a dissimilarity between the first CSI-RS and the second CSI-RS. The base station may transmit an indication for at least one of the first CSI-RS as the primary CSI-RS resource or the second CSI-RS as the subsidiary CSI-RS resource. The base station may transmit an explicit indication of the primary/subsidiary CSI-RS resource(s). Alternatively or additionally, the base station may transmit an implicit indication of the primary/subsidiary CSI-RS resource(s). The indication, whether explicit or implicit, may be transmitted by resource set component <NUM>. For example, the base station may indicate that the first CSI-RS includes the primary CSI-RS resource based on a configuration of a report quantity for the CQI, the RI, and the PMI for the first CSI-RS. The base station may indicate that the second CSI-RS includes the subsidiary CSI-RS resource based on a report quantity for the CQI, the RI, and the PMI not being configured for the second CSI-RS, such as being configured as "none.

The base station may transmit an indication of an association between the primary CSI-RS resource and the subsidiary CSI-RS resource, where the association indication is transmitted in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The indication of an association may be transmitted by association component <NUM> of apparatus <NUM>. The base station may transmit an indication of an association between the subsidiary CSI-RS resource and an SRS resource for the precoded SRS transmission, where the indication is received in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The indication may help the UE to determine the SRS resource for transmitting the precoded SRS.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an example apparatus <NUM> that supports CSF in accordance with aspects presented herein. The apparatus <NUM> is a BS and includes a baseband unit <NUM>. The baseband unit <NUM> may communicate through a cellular RF transceiver with the UE <NUM>. The baseband unit <NUM> may include a computer-readable medium / memory. The baseband unit <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the baseband unit <NUM>, causes the baseband unit <NUM> to perform the various functions described herein. The computer-readable medium / memory may also be used for storing data that is manipulated by the baseband unit <NUM> when executing software. The baseband unit <NUM> further includes a reception component <NUM>, a communication manager <NUM>, and a transmission component <NUM>. The components within the communication manager <NUM> may be stored in the computer-readable medium / memory and/or configured as hardware within the baseband unit <NUM>. The baseband unit <NUM> may be a component of the BS <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>.

The communication manager <NUM> includes a first CSI-RS component <NUM> configured to transmit a first CSI-RS on a first set of beams. The communication manager <NUM> includes a second CSI-RS component <NUM> configured to transmit a second CSI-RS on a second set of beams. The communication manager <NUM> includes a report component <NUM> configured to receive a report of the CQI and RI using an uplink control channel. The communication manager <NUM> includes an SRS component <NUM> to receive SRS from the UE, such as a precoded SRS and a non-precoded SRS. The communication manager <NUM> includes a determination component <NUM> configured to determine a PMI using a precoded SRS transmission. The communication manager <NUM> includes a precode component <NUM> configured to precode a the first and second CSI-RS transmissions. SRS component <NUM> may be configured to receive a non-precoded SRS prior to transmitting the first CSI-RS and the second CSI-RS. The communication manager <NUM> may include a resource set component <NUM> configured to transmit information about resource set(s) for the first and second CSI-RS. For example, resource set component <NUM> may be configured to transmit an indication of aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS that are associated with a trigger state. The resource set component <NUM> may be configured to transmit an indication of a single periodic or semi-persistent CSI-RS resource set for the first CSI-RS and the second CSI-RS, where the single periodic or semi-persistent CSI-RS resource set is configured with two CSI-RS resources. The resource set component <NUM> may be configured to transmit an indication for at least one of the first CSI-RS as the primary CSI-RS resource or the second CSI-RS as the subsidiary CSI-RS resource. The communication manager <NUM> may include association component <NUM> configured to transmit an association regarding the CSI-RS resource(s) or the SRS resource. For example, the association component <NUM> may be configured to transmit an indication that indicates an association between the primary CSI-RS resource and the subsidiary CSI-RS resource, where the association indication is transmitted in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The association component <NUM> may be configured to transmit an indication of an association between the subsidiary CSI-RS resource and an SRS resource for the precoded SRS transmission, where the indication is transmitted in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource.

In one configuration, the apparatus <NUM> for wireless communication includes means for transmitting a first CSI-RS on a first set of beams. The apparatus <NUM> includes means for transmitting a second CSI-RS on a second set of beams. The apparatus <NUM> includes means for receiving a report of a CQI and a RI based on the first CSI-RS, where the report is received in an uplink control channel from a UE. The apparatus <NUM> includes means for receiving a precoded SRS from the UE. The apparatus <NUM> includes means for determining a PMI based on the precoded SRS. The apparatus <NUM> includes means for receiving a non-precoded SRS prior to transmitting the first CSI-RS and the second CSI-RS. The apparatus <NUM> includes means for determining a precoder for the second CSI-RS based on an uplink channel estimate of the non-precoded SRS received from the UE, where the first CSI-RS is transmitted using a defined precoder. The apparatus <NUM> includes means for transmitting an indication of aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS that are associated with a trigger state. The apparatus <NUM> includes means for transmitting an indication of a single periodic or semi-persistent CSI-RS resource set for the first CSI-RS and the second CSI-RS, where the single periodic or semi-persistent CSI-RS resource set is configured with two CSI-RS resources. The apparatus <NUM> includes means for transmitting, to the UE, an indication for at least one of the first CSI-RS as the primary CSI-RS resource or the second CSI-RS as the subsidiary CSI-RS resource. The apparatus <NUM> includes means for transmitting an association indication that indicates an association between the primary CSI-RS resource and the subsidiary CSI-RS resource, where the association indication is transmitted in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The apparatus <NUM> includes means for transmitting an indication of an association between the subsidiary CSI-RS resource and an SRS resource for the precoded SRS, where the indication is transmitted in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource. The aforementioned means may be one or more of the aforementioned components of the apparatus <NUM> configured to perform the functions recited by the aforementioned means. As described herein, the apparatus <NUM> may include the TX Processor <NUM>, the RX Processor <NUM>, and the controller/processor <NUM>.

The following examples are illustrative only and aspects thereof may be combined with aspects of other examples or teaching described herein, without limitation.

Example <NUM> is a method of wireless communication at a UE, comprising: receiving a first CSI-RS on a first set of beams; receiving a second CSI-RS on a second set of beams; determining a CQI, a RI, and a PMI based on the first CSI-RS; transmitting a report that includes the CQI and the RI via an uplink control channel; and transmitting a precoded SRS that indicates the PMI.

In Example <NUM>, the method of Example <NUM> further includes determining a dissimilarity between the first CSI-RS and the second CSI-RS; and precoding a SRS to generate the precoded SRS transmission based on the dissimilarity determined between the first CSI-RS and the second CSI-RS to indicate the PMI.

In Example <NUM>, the method of Example <NUM> or Example <NUM> further includes transmitting a non-precoded SRS prior to receiving the first CSI-RS and the second CSI-RS.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes that the first CSI-RS is associated with a defined precoder, and wherein the second CSI-RS is associated with a precoder based at least in part on an uplink channel estimate of the non-precoded SRS.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes that a reporting setting of the UE for the report comprises a parameter indicating that the report setting is for FDD analog CSF.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes performing interference measurement on NZP CSI-RS signals or on CSI-IM signals, each CSI resource setting for channel measurement comprising two CSI-RS resource sets, wherein each of the two CSI-RS resource sets is configured with a single CSI-RS resource.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes performing an interference measurement on NZP CSI-RS signals or CSI-IM signals, each CSI resource setting for channel measurement comprising a single CSI-RS resource set configured with two CSI-RS resources.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes receiving a RRC message that includes a bitmap including an indication of aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS that are associated with a trigger state.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes receiving an indication of a single periodic or semi-persistent CSI-RS resource set for the first CSI-RS and the second CSI-RS, wherein the single periodic or semi-persistent CSI-RS resource set is configured with two CSI-RS resources.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes that the first CSI-RS comprises a primary CSI-RS resource for determining the CQI, the RI, and the PMI, and wherein the second CSI-RS comprises a subsidiary CSI-RS resource for determining a dissimilarity between the first CSI-RS and the second CSI-RS.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes receiving an indication that indicates the first CSI-RS is the primary CSI-RS resource or that the second CSI-RS is the subsidiary CSI-RS resource.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes that the UE determines that the first CSI-RS comprises the primary CSI-RS resource based on a configuration of a report quantity for the CQI, the RI, and the PMI for the first CSI-RS.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes that the UE determines that the second CSI-RS comprises the subsidiary CSI-RS resource based on a report quantity for the CQI, the RI, and the PMI not being configured for the second CSI-RS.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes receiving an association indication that indicates an association between the primary CSI-RS resource and the subsidiary CSI-RS resource, wherein the association indication is received in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource, or receiving an indication of an association between the subsidiary CSI-RS resource and an SRS resource for the precoded SRS transmission, wherein the indication is received in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource.

Example <NUM> is a device including one or more processors and one or more memories in electronic communication with the one or more processors storing instructions executable by the one or more processors to cause the device to implement a method as in any of Examples <NUM>-<NUM>.

Example <NUM> is a system or apparatus including means for implementing a method or realizing an apparatus as in any of Examples <NUM>-<NUM>.

Example <NUM> is a non-transitory computer readable medium storing instructions executable by one or more processors to cause the one or more processors to implement a method as in any of Examples <NUM>-<NUM>.

Example <NUM> is a method of wireless communication at a base station, comprising: transmitting a first CSI-RS on a first set of beams; transmitting a second CSI-RS on a second set of beams; receiving an uplink control channel from a UE that includes a report of a CQI and a RI based on the first CSI-RS; receiving a precoded SRS from the UE; and determining a PMI based on the precoded SRS.

In Example <NUM>, the method of Example <NUM> further includes that the precoded SRS is precoded based on a dissimilarity between a measurement of the first CSI-RS and the second CSI-RS at the UE.

In Example <NUM>, the method of Example <NUM> or Example <NUM> further includes receiving a non-precoded SRS prior to transmitting the first CSI-RS and the second CSI-RS; and determining a precoder for the second CSI-RS based on an uplink channel estimate of the non-precoded SRS received from the UE, wherein the first CSI-RS is transmitted using a defined precoder.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes that the reporting setting of the UE for the report comprises a parameter indicating the report setting is for FDD analog CSF.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes configuring two CSI-RS resource sets with a single CSI-RS resources for interference measurement to be performed on NZP CSI-RS signals or CSI-IM signals, each CSI resource setting for channel measurement comprising the two CSI-RS resource sets.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes configuring a single CSI-RS resource set with two CSI-RS resources for interference measurement to be performed on NZP CSI-RS signals or CSI-IM signals.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes transmitting a RRC message including an indication of aperiodic CSI-RS resource sets for the first CSI-RS and the second CSI-RS that are associated with a trigger state, wherein the aperiodic CSI-RS resource sets.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes transmitting an indication of a single periodic or semi-persistent CSI-RS resource set for the first CSI-RS and the second CSI-RS, wherein the single periodic or semi-persistent CSI-RS resource set is configured with two CSI-RS resources.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes transmitting, to the UE, an indication that the first CSI-RS is the primary CSI-RS resource or that the second CSI-RS is the subsidiary CSI-RS resource.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes that the primary CSI-RS resource comprises a configuration of a report quantity for the CQI, the RI, and the PMI.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes that the subsidiary CSI-RS resource does not comprise a report quantity for the CQI, the RI, and the PMI.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes transmitting an association indication that indicates an association between the primary CSI-RS resource and the subsidiary CSI-RS resource, wherein the association indication is transmitted in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource.

In Example <NUM>, the method of any of Examples <NUM>-<NUM> further includes transmitting an indication of an association between the subsidiary CSI-RS resource and an SRS resource for the precoded SRS, wherein the indication is transmitted in at least one of a first configuration for the primary CSI-RS resource or a second configuration for the subsidiary CSI-RS resource.

As used herein, "or" is used intended to be interpreted in the inclusive sense, unless otherwise explicitly indicated. For example, "a or b" may include a only, b only, or a combination of a and b. As used herein, a phrase referring to "at least one of" or "one or more of" a list of items refers to any combination of those items, including single members. For example, "at least one of: a, b, or c" is intended to cover the examples of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.

The various illustrative components, logic, logical blocks, modules, circuits, operations and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware or software, including the structures disclosed in this specification.

Various modifications to the implementations described in this disclosure may be readily apparent to persons having ordinary skill in the art, and the generic principles defined herein may be applied to other implementations without departing from the scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

Additionally, various features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. As such, although features may be described above as acting in particular combinations, and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Claim 1:
A method (<NUM>) of wireless communication at a user equipment, UE, comprising:
transmitting a non-precoded sounding reference signal, SRS;
subsequently receiving (<NUM>) a first channel state information reference signal, CSI-RS, on a first set of beams, wherein the first CSI-RS is associated with a defined precoder;
receiving (<NUM>) a second CSI-RS on a second set of beams, wherein the second CSI-RS is associated with a precoder based at least in part on an uplink channel estimate of the non-precoded SRS;
determining (<NUM>) a channel quality indicator, CQI, a rank indicator, RI, and a precoding matrix indicator, PMI, based on the first CSI-RS;
transmitting (<NUM>) a report that includes the CQI and the RI via an uplink control channel;
determining a dissimilarity between the first CSI-RS and the second CSI-RS;
precoding a SRS based on the dissimilarity determined between the first CSI-RS and the second CSI-RS to indicate the PMI; and
transmitting (<NUM>) the precoded SRS.