Patent Description:
Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, singlecarrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE).

A BS may be referred to as a Node B, a gNB, an access point (AP), a radio head, a transmit receive point (TRP), a new radio (NR) BS, a <NUM> Node B, and/or the like.

<NPL>, relates to a discussion of agreements made with respect to partial reciprocity based CSU acquisition mechanism.

<NPL>, relates to an analysis and evaluation of potential schemes for CSI feedback based on full and partial reciprocity.

Multiple access technologies have been adopted in various telecommunication standards. Wireless communication standards provide common protocols to enable different devices (e.g., user equipment) to communicate on a municipal, national, regional, and even global level. As demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE and NR technologies. These improvements can apply to other multiple access technologies and the telecommunication standards that employ these technologies.

The invention is defined in the claims.

So that the above-recited features of the present disclosure can be understood in detail, a more particular description is provided herein, with some aspects of the disclosure being illustrated in the appended drawings. However, the appended drawings illustrate only some aspects of this disclosure and are therefore not to be considered limiting of the scope of the disclosure.

These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, and/or the like (collectively referred to as "elements" or "features").

While some aspects may be described herein using terminology commonly associated with <NUM> and/or <NUM> wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as <NUM> and later, including NR technologies.

While aspects and embodiments are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, packaging arrangements. For example, embodiments and/or uses may come about via integrated chip embodiments and/or other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, AI-enabled devices, and/or the like). While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or OEM devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described embodiments. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including one or more antennas, RF-chains, power amplifiers, modulators, buffers, processors, interleavers, adders/summers, and/or the like). It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.

Each BS may provide communication coverage for a particular area (e.g., a fixed or changing geographical area). In some scenarios, BSs <NUM> may be stationary or non-stationary. In some non-stationary scenarios, mobile BSs <NUM> may move with varying speeds, direction, and/or heights. In 3GPP, the term "cell" can refer to a coverage area of a BS <NUM> and/or a BS subsystem serving this coverage area, depending on the context in which the term is used.

Additionally, or alternatively, a BS may support access to an unlicensed RF band (e.g., a Wi-Fi band and/or the like).

In other scenarios, BSs may be implemented in a software defined network (SDN) manner or via network function virtualization (NFV) manner.

A UE may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, biometric sensors/devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio), a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, robotics, drones, implantable devices, augmented reality devices, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.

These components may be integrated in a variety of combinations and/or may be stand-alone, distributed components considering design constraints and/or operational preferences.

A UE performing scheduling operations can include or perform base-station-like functions in these deployment scenarios.

The T and R antennas may be configured with multiple antenna elements formed in an array for MIMO or massive MIMO deployments that can occur in millimeter wave (mmWave or mmW) communication systems.

At base station <NUM>, a transmit processor <NUM> can carry out a number of functions associated with communications. For example, transmit processor <NUM> may receive data from a data source <NUM> for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS(s) selected for the UE, and provide data symbols for all UEs. A transmit (TX) multiple-input multipleoutput (MIMO) processor <NUM> may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t.

At UE <NUM>, antennas 252a through 252r may receive downlink RF signals. The downlink RF signals may be received from and/or may be transmitted by one or more base stations <NUM>. The signals can be provided to demodulators (DEMODs) 254a through 254r, respectively.

For uplink communications, a UE <NUM> may transmit control information and/or data to another device, such as one or more base stations <NUM>. For example, at UE <NUM>, a transmit processor <NUM> may receive and process data from a data source <NUM> and control information (e.g., for reports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) from controller/processor <NUM>.

Controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform one or more techniques associated with channel state information (CSI) acquisition for partial reciprocity, as described in more detail elsewhere herein. For example, controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform or direct operations of, for example, process <NUM> of <FIG>, process <NUM> of <FIG>, and/or other processes as described herein. Memories <NUM> and <NUM> may store data and program codes for base station <NUM> and UE <NUM>, respectively.

In some aspects, the UE <NUM> may include a variety of means or components for implementing communication functions. For example, the variety of means may include means for transmitting a sounding reference signal (SRS) that indicates that the UE <NUM> is configured with a quantity of receive elements that is greater relative to a quantity of transmit elements with which the UE <NUM> is configured, means for receiving, based at least in part on transmitting the SRS, a first CSI reference signal (CSI-RS) set and a second CSI-RS set, means for transmitting a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set, and/or the like.

In some aspects, the UE <NUM> may include a variety of structural components for carrying out functions of the various means. For example, structural components that carry out functions of such means may include one or more components of UE <NUM> described in connection with <FIG>, such as antenna <NUM>, DEMOD <NUM>, MOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, controller/processor <NUM>, and/or the like.

In some aspects, the base station <NUM> may include a variety of means or components for implementing communication functions. For example, the variety of means may include means for receiving, from a UE <NUM>, an SRS that indicates that the UE <NUM> is configured with a quantity of receive elements that is greater relative to a quantity of transmit elements with which the UE <NUM> is configured, means for transmitting, based at least in part on receiving the SRS, a first CSI-RS set and a second CSI-RS set, means for receiving, from the UE, a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set, and/or the like.

In some aspects, the base station <NUM> may include a variety of structural components for carrying out functions of the various means. For example, structural components that carry out functions of such means may include one or more components of base station <NUM> described in connection with <FIG>, such as transmit processor <NUM>, TX MIMO processor <NUM>, DEMOD <NUM>, MOD <NUM>, antenna <NUM>, MIMO detector <NUM>, receive processor <NUM>, controller/processor <NUM>, and/or the like.

<FIG> shows an example frame structure <NUM> for FDD in a telecommunications system (e.g., NR). Each subframe may have a predetermined duration (e.g., <NUM>) and may include a set of slots (e.g., <NUM>m slots per subframe are shown in <FIG>, where m is a numerology used for a transmission, such as <NUM>, <NUM>,<NUM>, <NUM>, <NUM>, and/or the like). In some aspects, a scheduling unit for the FDD may frame-based, subframe-based, slot-based, symbolbased, and/or the like.

Each resource block may cover a set to of subcarriers (e.g., <NUM> subcarriers) in one slot and may include a number of resource elements.

An interlace structure may be used for each of the downlink and uplink for FDD in certain telecommunications systems (e.g., NR). For example, Q interlaces with indices of <NUM> through Q - <NUM> may be defined, where Q may be equal to <NUM>, <NUM>, <NUM>, <NUM>, or some other value. Each interlace may include slots that are spaced apart by Q frames. In particular, interlace q may include slots q, q + Q, q + 2Q, etc., where q ∈ {<NUM>,.

A UE and a BS may perform wireless communication in a wireless network. To facilitate bandwidth selection and parameters for the wireless communication link between the UE and the BS, a UE may transmit an SRS to the BS. The BS may perform one or more measurements of the SRS (which may be referred to as a channel estimation) and may select the bandwidth and/or other parameters for the wireless communication link based at least in part on the results of the one or more measurements. In some cases, a UE may support full reciprocity, in which case the UE is configured and/or equipped with an equal quantity of transmit elements (e.g., antennas, antenna arrays, antenna panels, and/or the like) and receive elements. In this case, the BS may use the result of an uplink channel estimation for downlink channel estimation due to the equality between the transmit elements and receive elements of the UE. However, if a UE is configured and/or equipped with an unequal quantity of transmit elements and receive elements (which may be referred to as partial reciprocity), the BS may be unable to estimate the downlink based at least in part on full reciprocity with the uplink.

Some techniques and apparatuses described herein provide CSI acquisition for partial reciprocity. A UE that may not support full reciprocity (e.g., a UE that is configured and/or equipped with a greater quantity of receive elements relative to a quantity of transmit elements) may transmit an SRS to a BS. The BS may transmit, to the UE, a first CSR-RS set and a second CSI-RS set. Transmissions of the first CSI-RS set may be precoded based at least in part on the SRS. Transmissions of the second CSI-RS set may be non-precoded and/or may be precoded using a precoder that is orthogonal to a precoder that is used to precode the transmissions of the first CSI-RS set. The UE may generate a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set. The CSI report may indicate various joint and/or individual channel estimation parameters, such as a joint and/or individual precoder matrix indicators (PMIs), joint and/or individual rank indicators (RIs), joint and/or individual channel quality indicators (CQIs), joint and/or individual CSI-RS resource indicators (CRIs), and/or the like. In this way, the joint and/or individual channel estimation parameters that are determined from a combination of a precoded CSI-RS set (e.g., based at least in part on an SRS transmitted from the UE) and precoded and/or non-precoded CSI-RS set increases the accuracy and performance of the CSI report and reduces the payload of the CSI report, and may be used by the BS to improve downlink channel quality for partial reciprocity.

<FIG> are diagrams illustrating examples <NUM> of CSI acquisition for partial reciprocity, in accordance with various aspects of the present disclosure. As shown in <FIG>, examples <NUM> may include communication between a BS (e.g., BS <NUM>) and a UE (e.g., UE <NUM>). In some aspects, the BS and the UE may be included in a wireless network (e.g., wireless network <NUM>). In some aspects, the BS and the UE may communicate using a frame structure (e.g., frame structure <NUM> illustrated in <FIG> and/or another frame structure), a slot format (e.g., slot format <NUM> illustrated in <FIG> and/or another slot format), and/or the like.

In some aspects, the UE may be configured and/or equipped with an unequal quantity of transmit elements and receive elements (e.g., a greater quantity of receive elements relative to the quantity of transmit elements). In this case, the BS may be unable to estimate the downlink of the wireless communication link using full reciprocity channel estimation techniques.

As shown in <FIG>, and by reference number <NUM>, in order to assist the BS in fully estimating the downlink, the UE may transmit an SRS to the BS. The SRS may include a reference signal (e.g., that is based at least in part on a Zadoff Chu sequence and/or another type of sequence) that the UE transmits on the uplink of the wireless communication link. In some aspects, the UE may transmit a plurality of SRSs to the BS, where each SRS is transmitted from a respective transmit element of the UE.

In some aspects, the SRS may indicate to the BS that the UE supports partial reciprocity. For example, the SRS may indicate that the UE is configured and/or equipped with a particular quantity of transmit elements, may indicate that the UE is configured and/or equipped with a particular quantity of receive elements that is greater relative to the quantity of transmit elements, may indicate that the UE supports partial reciprocity, and/or the like. Additionally and/or alternatively, the indication that the UE supports partial reciprocity may be indicated in other communications with the BS, such as during a random access channel (RACH) procedure, UE uplink signaling, and/or the like.

As further shown in <FIG>, and by reference number <NUM>, the BS may transmit a plurality of CSI-RS sets to the UE based at least in part on receiving the SRS and/or the indication that the UE supports partial reciprocity. The plurality of CSI-RS sets may include, for example, a first CSI RS set and a second CSI-RS set. The first CSI-RS set and the second CSI-RS set may each include one or more CSI-RS transmissions. A CSI-RS may include a reference signal (e.g., a downlink reference signal) that is generated based at least in part on a sequence (e.g., a Zadoff Chu sequence, a Gold sequence, and/or the like). The UE may perform one or more measurements associated with a CSI-RS, and may generate a CSI report that indicates results of the one or more measurements and/or that indicates one or more parameters that are based at least in part on the results of the one or more measurements.

In some aspects, the one or more CSI-RS transmissions, included in the first CSI-RS set, may be associated with respective CSI-RS ports that are associated with the SRS. For example, transmissions of the CSI-RS ports may be precoded based at least in part on the SRS. In some aspects, the one or more CSI-RS transmissions, included in the second CSI-RS set, may be associated with transmissions of respective CSI-RS ports that are non-precoded and/or are precoded using a precoder that is orthogonal to a precoder that is used to precode the transmissions of the first CSI-RS set (e.g., the transmissions of the second CSI-RS set are on a subspace of that is orthogonal to the subspace of the precoder used for the first CSI-RS set, which ensures the orthogonality of PMIs for the first CSI-RS set and the second CSI-RS set).

As shown in <FIG> and <FIG>, the BS may configure the first CSI-RS set and/or the second CSI-RS set using various resource and/or transmission configurations. <FIG> illustrates various examples of resource set configurations for the first CSI-RS set and the second CSI-RS set. Other examples of resource set configurations may be used. As shown in Example <NUM>, the BS may independently configure respective resource sets for the first CSI-RS set and the second CSI-RS set. In some aspects, the respective resource sets may be different and/or non-overlapping resource sets, may be partially overlapping resources, and/or the like. For example, the BS may configure a first resource set, for the first CSI-RS set, that includes time-domain and/or frequency-domain resources <NUM>-n, and a second resource set, for the second CSI-RS set, that includes a different set of time-domain and/or frequency-domain resources <NUM>-m.

As shown in Example <NUM>, the BS may jointly configure a resource set for the first CSI-RS set and the second CSI-RS set. In this case, the resource set may include different and/or non-overlapping resource subsets (e.g., time-domain and/or frequency-domain resource subsets) for the first CSI-RS set and the second CSI-RS set, may include partially overlapping resource subsets, and/or the like. As shown in Example <NUM>, the BS may jointly configure a resource set for the first CSI-RS set and the second CSI-RS set, in which the first CSI-RS set and the second CSI-RS set share the same CSI resources (e.g., the same time-domain and/or frequency-domain resources).

<FIG> illustrates an example configuration for SRS transmit switching for the first CSI-RS set. Other examples for SRS transmit switching configurations may be used. As indicated above, in some aspects, the UE may be configured to transmit an SRS across a plurality of transmit elements. This may be referred to as SRS transmit switching. In this case, the BS may configure the first CSI-RS set based at least in part on whether the UE implements SRS transmit switching. In some aspects, the BS may configure the bandwidth, periodicity, and/or the like of the first CSI-RS set based at least in part on which transmit element is used to transmit the SRS. For example, and as shown in <FIG>, the BS may configure the bandwidth, periodicity, and/or the like of the first CSI-RS set based at least in part on whether the UE transmits the SRS from Tx1, Tx2, Txk, and/or the like.

As shown in <FIG>, and by reference number <NUM>, the UE may generate and transmit, to the BS, a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set. In some aspects, the UE may transmit the CSI report in an uplink control information (UCI) communication and/or another type of communication on the uplink. In some aspects, the UE may generate and transmit the CSI report based at least in part on a CSI report configuration. The CSI report configuration may indicate one or more parameters for generating the CSI report. In some aspects, the BS may transmit the CSI report configuration to the UE, and the UE may receive the CSI report configuration from the BS. In some aspects, the UE may receive the CSI report configuration from another BS, may be hardcoded with the CSI report configuration, and/or the like. In some aspects, the UE may receive the CSI report configuration in a radio resource control (RRC) communication, a downlink control information (DCI) communication, a medium access control (MAC) control element (MAC-CE) communication, a system information communication (e.g., a physical broadcast channel (PBCH) communication, a system information block (SIB), a remaining minimum system information (RMSI) communication, an other system information (OSI) communication, and/or the like), and/or the like.

In some aspects, the one or more parameters may include a parameter that indicates and/or specifies a resource set configuration for the first CSI-RS set and/or the second CSI-RS set. For example, the parameter may indicate and/or specify an example resource set configuration illustrated in <FIG> and/or another resource set configuration. In this case, the UE may generate the CSI report based at least in part on the resource set configuration for the first CSI-RS set and/or the second CSI-RS set.

In some aspects, the one or more parameters for generating the CSI report may include a parameter that indicates and/or specifies whether the UE is to include, in the CSI report, a first PMI associated with the first CIS-RS set, a second PMI associated with the second CSI-RS set, and/or a joint PMI associated with the first CSI-RS set and the second CSI-RS set. A PMI may be associated with a precoder matrix, selected from a codebook, that corresponds to a beam or combination of beams requested by the UE. Moreover, the one or more parameters may include a parameter that indicates and/or specifies a codebook type associated with the first CSI-RS set and/or a codebook type associated with the second CSI-RS set. For example, the codebook type for each CSI-RS set may be selected from various types of codebooks, such as an NR Type-I codebook an NR Type-II codebook (e.g., a codebook that permits higher-resolution beam selection reporting relative to an NR Type-I codebook), and/or the like. Accordingly, the UE may select the first PMI for the first CSI-RS set from the codebook associated with the first CSI-RS set, may select the second PMI for the second CSI-RS set from the codebook associated with the second CSI-RS set, and/or may select the joint PMI from either codebook.

In some aspects, the one or more parameters may include a parameter for determining the first PMI, the second PMI, and/or the joint PMI. For example, the parameter may indicate and/or specify that the UE is to determine or identify the first PMI as a matrix that is sized based at least in part on a quantity of layers associated with the first CSI-RS set and a quantity of CSI-RS ports associated with the first CSI-RS set (e.g., a matrix that is sized according to p × r, where r corresponds to the quantity of layers and p corresponds to the quantity of CSI-RS ports). As another example, the parameter may indicate and/or specify that the UE is to determine or identify the second PMI as a matrix that is sized based at least in part on a quantity of layers associated with the second CSI-RS set and a quantity of CSI-RS ports associated with the second CSI-RS set (e.g., a matrix that is sized according to q × s, where s corresponds to the quantity of layers and q corresponds to the quantity of CSI-RS ports). As another example, the parameter may indicate and/or specify that the UE is to determine the joint PMI based at least in part on the first PMI and the second PMI. For example, the UE may determine or identify the joint PMI based at least in part on <MAT> where W corresponds to the joint PMI having R columns (layers) (e.g., R = r + s), Wp corresponds to the first PMI, and Wq corresponds to the second PMI.

In some aspects, the one or more parameters may include a parameter that indicates and/or specifies whether the UE is to include, in the CSI report, a first rank indicator (RI) (e.g., an indicator for a quantity of layers requested by the UE) associated with the first CSI-RS set and determined based at least in part on the first PMI (e.g., based at least in part on the total quantity of layers associated with the first PMI), a second RI associated with the second CSI-RS set and determined based at least in part on the second PMI (e.g., based at least in part on the total quantity of layers associated with the second PMI), and/or a joint RI that is determined based at least in part on the joint PMI (e.g., which may be based at least in part on the total quantity of layers associated with the first PMI and the total quantity of layers associated with the second PMI). In some aspects, the one or more parameters may include a parameter that indicates and/or specifies a maximum and/or minimum rank for the first RI, the second RI, and/or the joint RI. In some aspects, the one or more parameters may include a parameter that indicates and/or specifies the first RI (e.g., if the first RI is to be a fixed value corresponding to the quantity of CSI-RS ports associated with the first CSI-RS set). In this case, the UE may omit the indication of the first RI from the CSI report to reduce the overhead of the CSI report.

In some aspects, the one or more parameters may include a parameter that indicates and/or specifies whether the UE is to include, in the CSI report, a first channel quality indicator (CQI) (e.g., a value that indicates a channel quality of the downlink) associated with the first CSI-RS set and the first PMI, a second CQI associated with the second CSI-RS set and the second PMI, and/or a joint CQI that associated with the joint PMI (e.g., which may be based at least in part on the first PMI and the second PMI). In some aspects, the UE may determine the first CQI, the second CQI, and/or the joint CQI based at least in part on performing one or more channel quality measurements, such as a signal-to-noise-plus-interference ratio (SINR) measurement, a reference signal received quality (RSRQ) measurement, a reference signal received power (RSRP) measurement, and/or the like.

In some aspects, the one or more parameters may include a parameter that indicates and/or specifies whether the UE is to include, in the CSI report, a first CSI-RS resource indicator (CRI) (e.g., an indicator of a set of time-domain resources and/or frequency-domain resources) associated with the first CSI-RS set and the first PMI, a second CRI associated with the second CSI-RS set and the second PMI, and/or a joint CRI that associated with the joint PMI (e.g., which may be based at least in part on the first PMI and the second PMI), the first CSI-RS set, and/or the second CSI-RS set. In some aspects, the first CRI may indicate and/or specify a resource selection from the resource set or resource subset configured for the first CSI-RS set. In some aspects, the second CRI may indicate and/or specify a resource selection from the resource set or resource subset configured for the second CSI-RS set. In some aspects, the joint CRI may indicate and/or specify a resource selection from the resource set or resource subset configured for the first CSI-RS set and/or the resource set or resource subset configured for the second CSI-RS set. In this case, the joint CRI may indicate a first value (e.g., CRI=<NUM>) to indicate a selection of a CSI resource from the resource set or resource subset configured for the first CSI-RS set, may indicate a second value (e.g., CRI=<NUM>) to indicate a selection of a CSI resource from the resource set or resource subset configured for the second CSI-RS set, may indicate a third value (e.g., CRI=<NUM>) to indicate a selection of a CSI resource from the resource set or resource subset configured for the first CSI-RS set and from the resource set or resource subset configured for the second CSI-RS set.

In some aspects, the one or more parameters may include a parameter that specifies whether the UE is to transmit a CSI report only for an overlapping bandwidth region between the first CSI-RS set and the second CSI-RS set, or whether the UE is to transmit a CSI report for the overlapping bandwidth region and for non-overlapping bandwidth regions for the first CSI-RS set and the second CSI-RS set.

<FIG> illustrates example configurations for generating and transmitting CSI reports for overlapping CSI-RS sets. Other example configurations may be used. As shown in Example <NUM>, the CSI report configuration may indicate and/or specify that the UE is to generate and transmit a CSI report that includes only a joint CSI report for an overlapping region associated with the first CSI-RS set and the second CSI-RS set. The overlapping region may include a region in the bandwidth of the first CSI-RS set and the bandwidth of the second CSI-RS set that at least partially overlap. As shown in Example <NUM>, the CSI report configuration may indicate and/or specify that the UE is to generate and transmit a CSI report that includes a joint CSI report for an overlapping region associated with the first CSI-RS set and the second CSI-RS set, as well as individual CSI reports for the non-overlapping regions of the first CSI-RS set and the second CSI-RS set. In this case, the joint CSI report may include an indication of a joint PMI, a joint RI, a joint CQI, and/or a joint CRI associated with the first CSI-RS set and the second CSI-RS set, the individual CSI report associated with the first CSI-RS set may include an indication of a PMI, an RI, a CQI, and/or a CRI associated with the first CSI-RS set, the individual CSI report associated with the second CSI-RS set may include an indication of a PMI, an RI, a CQI, and/or a CRI associated with the second CSI-RS set, and/or the like.

In this way, a UE that may not support full reciprocity (e.g., a UE that is configured and/or equipped with a greater quantity of receive elements relative to a quantity of transmit elements) may transmit an SRS to a BS. The BS may transmit, to the UE, a first CSR-RS set and a second CSI-RS set. Transmissions of the first CSI-RS set may be precoded based at least in part on the SRS, and transmissions of the second CSI-RS set may be non-precoded and/or precoded. The UE may generate a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set. The CSI report may indicate various joint and/or individual channel estimation parameters, such as a joint and/or individual PMIs, joint and/or individual RIs, joint and/or individual CQIs, joint and/or individual CRIs, and/or the like. In this way, the joint and/or individual channel estimation parameters that are determined from a combination of a precoded CSI-RS set (e.g., based at least in part on an SRS transmitted from the UE) and a non-precoded and/or precoded CSI-RS set increases the accuracy and performance of the CSI report and reduces the payload of the CSI report, and may be used by the BS to improve downlink channel quality for partial reciprocity. For example, the BS may select beams, layers, streams, bandwidth allocation, transport block size, and/or other parameters for the downlink and/or the uplink of the wireless communication link based at least in part on the information indicated in the CSI report.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where a UE (e.g., UE <NUM>) performs operations associated with CSI acquisition for partial reciprocity.

As shown in <FIG>, in some aspects, process <NUM> may include transmitting an SRS that indicates that the UE is configured with a quantity of receive elements that is greater relative to a quantity of transmit elements with which the UE is configured (block <NUM>). For example, the UE (e.g., using receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may transmit an SRS that indicates that the UE is configured with a quantity of receive elements that is greater relative to a quantity of transmit elements with which the UE is configured, as described above.

As further shown in <FIG>, in some aspects, process <NUM> may include receiving, based at least in part on transmitting the SRS, a first CSI-RS set and a second CSI-RS set (block <NUM>). For example, the UE (e.g., using receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may receive, based at least in part on transmitting the SRS, a first CSI-RS set and a second CSI-RS set, as described above.

As further shown in <FIG>, in some aspects, process <NUM> may include transmitting a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set (block <NUM>). For example, the UE (e.g., using receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may transmit a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set, as described above.

In a first aspect, the first CSI-RS set is based at least in part on the SRS. In a second aspect, alone or in combination with the first aspect, the first CSI-RS includes one or more CSI-RS ports associated with the SRS. In a third aspect, alone or in combination with one or more of the first and second aspects, transmissions of the first CSI-RS set are precoded based at least in part on the SRS. In a fourth aspect, alone or in combination with one or more of the first through third aspects, transmissions of the second CSI-RS set are non-precoded or are precoded using a precoder that is orthogonal to a precoder that is used to precode the transmissions of the first CSI-RS set. In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, process <NUM> further comprises generating the CSI report based at least in part on the first CSI-RS set and the second CSI-RS set. In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, process <NUM> further comprises receiving an indication of a CSI report configuration, and generating the CSI report comprises generating the CSI report based at least in part on the CSI report configuration.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the CSI report configuration indicates one or more parameters for the CSI report, and the one or more parameters comprise at least one of a parameter that specifies maximum rank for a joint RI associated with the first CSI-RS set and the second CSI-RS set, a parameter that specifies a maximum rank for a first RI associated with the first CSI-RS set, a parameter that specifies a minimum rank for the first RI, a parameter that specifies the first RI, a parameter that specifies a maximum rank for a second RI associated with the second CSI-RS set, a parameter that specifies a first codebook type for the first CSI-RS set, or a parameter that specifies a second codebook type for the second CSI-RS set. In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the CSI report indicates at least one of a first PMI associated with the first CSI-RS set, a second PMI associated with the second CSI-RS set, a joint PMI associated with the first CSI-RS set and the second CSI-RS set, a first RI associated with the first PMI, a second RI associated with the second PMI, a joint RI associated with the joint PMI, a CQI associated with the first PMI and the second PMI, a first CRI associated with the first PMI, a second CRI associated with the second PMI, or a joint CRI associated with the joint PMI.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the CSI report comprises a first PMI for the first CSI-RS set and a second PMI for the second CSI-RS set, and process <NUM> further comprises identifying the first PMI based at least in part on a first quantity of CSI-RS ports associated with the first CSI-RS set and a first quantity of layers associated with the first CSI-RS set and identifying the second PMI based at least in part on a second quantity of CSI-RS ports associated with the second CSI-RS set and a second quantity of layers associated with the second CSI-RS set. In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the first PMI and the second PMI are each configured with an NR Type-I codebook or an NR Type-II codebook.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the CSI report comprises a joint RI for the first CSI-RS set and the second CSI-RS set, and process <NUM> further comprises determining the joint RI based at least in part on a first quantity of layers associated with a first precoder matrix indicator (PMI) associated with the first CSI-RS set and a second quantity of layers associated with a second PMI associated with the second CSI-RS set. In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the first CSI-RS set is configured with a first set of time-domain resources and frequency-domain resources, and the second CSI-RS set is configured with a second set of time-domain resources and frequency-domain resources that is different from the first set of time-domain resources and frequency-domain resources. In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, the CSI report comprises a joint CRI associated with the first CSI-RS set and the second CSI-RS set, and the joint CRI indicates the first set of time-domain resources and frequency-domain resources or the second set of time-domain resources and frequency-domain resources.

In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, the first CSI-RS set is configured with a first subset of a set of time-domain resources and frequency-domain resources, and the second CSI-RS set is configured with a second subset, of the set of time-domain resources and frequency-domain resources, that is different from the first subset. In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, the CSI report comprises a joint CRI associated with the first CSI-RS set and the second CSI-RS set, and the joint CRI indicates at least one of the first subset or the second subset. In a sixteenth aspect, alone or in combination with one or more of the first through fifteenth aspects, the first CSI-RS set and the second CSI-RS are included in a same CSI-RS resource. In a seventeenth aspect, alone or in combination with one or more of the first through sixteenth aspects, the CSI report comprises: a first CRI associated with the first CSI-RS set; and a second CRI associated with the second CSI-RS set.

In an eighteenth aspect, alone or in combination with one or more of the first through seventeenth aspects, a configuration for the first CSI-RS set is based at least in part on a configuration for the SRS, and the configuration for the SRS comprises at least one of a periodicity parameter associated with the SRS or a bandwidth parameter associated with the SRS. In a nineteenth aspect, alone or in combination with one or more of the first through eighteenth aspects, a first bandwidth of the first CSI-RS set and a second bandwidth of the second CSI-RS set partially overlap, and the CSI report is associated with a partial overlapping region of the first bandwidth and the second bandwidth. In a twentieth aspect, alone or in combination with one or more of the first through nineteenth aspects, a first bandwidth of the first CSI-RS set and a second bandwidth of the second CSI-RS set partially overlap, and the CSI report comprises a first CSI report, associated with a non-overlapping region of the first bandwidth, that includes a first precoding matrix indicator (PMI) associated with the first CSI-RS set, a second CSI report, associated with a non-overlapping region of the second bandwidth, that includes a second PMI associated with the second CSI-RS set, and a third CSI report, associated with a partial overlapping region of the first bandwidth and the second bandwidth, that includes a joint PMI associated with the first CSI-RS set and the second CSI-RS set.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a BS, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where a BS (e.g., BS <NUM>) performs operations associated with CSI acquisition for partial reciprocity.

As shown in <FIG>, in some aspects, process <NUM> may include receiving, from a UE, an SRS that indicates that the UE is configured with a quantity of receive elements that is greater relative to a quantity of transmit elements with which the UE is configured (block <NUM>). For example, the BS (e.g., using transmit processor <NUM>, receive processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may receive, from a UE, an SRS that indicates that the UE is configured with a quantity of receive elements that is greater relative to a quantity of transmit elements with which the UE is configured, as described above.

As further shown in <FIG>, in some aspects, process <NUM> may include transmitting, based at least in part on receiving the SRS, a first CSI-RS set and a second CSI-RS set (block <NUM>). For example, the BS (e.g., using transmit processor <NUM>, receive processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may transmit, based at least in part on receiving the SRS, a first CSI-RS set and a second CSI-RS set, as described above.

As further shown in <FIG>, in some aspects, process <NUM> may include receiving, from the UE, a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set (block <NUM>). For example, the BS (e.g., using transmit processor <NUM>, receive processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may receive, from the UE, a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set, as described above.

In a first aspect, the first CSI-RS set is based at least in part on the SRS. In a second aspect, alone or in combination with the first aspect, the first CSI-RS includes one or more CSI-RS ports associated with the SRS. In a third aspect, alone or in combination with one or more of the first and second aspects, process <NUM> further comprises precoding the first CSI-RS set based at least in part on the SRS. In a fourth aspect, alone or in combination with one or more of the first through third aspects, transmissions of the second CSI-RS set are non-precoded or are precoded using a precoder that is orthogonal to a precoder that is used to precode the transmissions of the first CSI-RS set. In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, process <NUM> further comprises transmitting, to the UE, an indication of a CSI report configuration, and the CSI report is based at least in part on the CSI report configuration.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the CSI report configuration indicates one or more parameters for the CSI report, and the one or more parameters comprise at least one of: a parameter that specifies maximum rank for a joint RI associated with the first CSI-RS set and the second CSI-RS set, a parameter that specifies a maximum rank for a first RI associated with the first CSI-RS set, a parameter that specifies a minimum rank for the first RI, a parameter that specifies the first RI, a parameter that specifies a maximum rank for a second RI associated with the second CSI-RS set, a parameter that specifies a first codebook type for the first CSI-RS set, or a parameter that specifies a second codebook type for the second CSI-RS set. In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the CSI report indicates at least one of a first PMI associated with the first CSI-RS set, a second PMI associated with the second CSI-RS set, a joint PMI associated with the first CSI-RS set and the second CSI-RS set, a first RI associated with the first PMI, a second RI associated with the second PMI, a joint RI associated with the joint PMI, a CQI associated with the first PMI and the second PMI, a first CRI associated with the first PMI, a second CRI associated with the second PMI, or a joint CRI associated with the joint PMI.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the CSI report comprises a first PMI for the first CSI-RS set and a second PMI for the second CSI-RS set, and the first PMI and the second PMI are each configured with an NR Type-I codebook or an NR Type-II codebook. In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the CSI report comprises: a joint RI for the first CSI-RS set and the second CSI-RS set, and the joint RI is based at least in part on a first quantity of layers associated with a first PMI associated with the first CSI-RS set and a second quantity of layers associated with a second PMI associated with the second CSI-RS set. In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the first CSI-RS set is configured with a first set of time-domain resources and frequency-domain resources, and the second CSI-RS set is configured with a second set of time-domain resources and frequency-domain resources that is different from the first set of time-domain resources and frequency-domain resources.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the CSI report comprises a joint CRI associated with the first CSI-RS set and the second CSI-RS set, the joint CRI indicates the first set of time-domain resources and frequency-domain resources or the second set of time-domain resources and frequency-domain resources In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the first CSI-RS set is configured with a first subset of a set of time-domain resources and frequency-domain resources, and the second CSI-RS set is configured with a second subset, of the set of time-domain resources and frequency-domain resources, that is different from the first subset. In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, the CSI report comprises a joint CRI associated with the first CSI-RS set and the second CSI-RS set, and the joint CRI indicates at least one of the first subset or the second subset.

In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, the first CSI-RS set and the second CSI-RS are included in a same CSI-RS resource. In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, the CSI report comprises a first CRI associated with the first CSI-RS set; and a second CRI associated with the second CSI-RS set. In a sixteenth aspect, alone or in combination with one or more of the first through fifteenth aspects, a configuration for the first CSI-RS set is based at least in part on a configuration for the SRS, and the configuration for the SRS comprises at least one of a periodicity parameter associated with the SRS or a bandwidth parameter associated with the SRS. In a seventeenth aspect, alone or in combination with one or more of the first through sixteenth aspects, a first bandwidth of the first CSI-RS set and a second bandwidth of the second CSI-RS set partially overlap, and the CSI report is associated with a partial overlapping region of the first bandwidth and the second bandwidth.

In an eighteenth aspect, alone or in combination with one or more of the first through seventeenth aspects, a first bandwidth of the first CSI-RS set and a second bandwidth of the second CSI-RS set partially overlap, and the CSI report comprises a first CSI report, associated with a non-overlapping region of the first bandwidth, that includes a first PMI associated with the first CSI-RS set, a second CSI report, associated with a non-overlapping region of the second bandwidth, that includes a second PMI associated with the second CSI-RS set, and a third CSI report, associated with a partial overlapping region of the first bandwidth and the second bandwidth, that includes a joint PMI associated with the first CSI-RS set and the second CSI-RS set.

Claim 1:
A method (<NUM>) of wireless communication performed by a user equipment (UE), the method (<NUM>) comprising:
transmitting (<NUM>) a sounding reference signal, SRS, that indicates that the UE is configured with a quantity of receive elements that is greater relative to a quantity of transmit elements with which the UE is configured;
receiving (<NUM>), based at least in part on transmitting the SRS, a first channel state information, CSI, reference signal, CSI-RS, set and a second CSI-RS set, wherein transmissions of the first CSI-RS set are precoded based at least in part on the SRS, and wherein transmissions of the second CSI-RS set are non-precoded or are precoded using a precoder that is orthogonal to a precoder that is used to precode the transmissions of the first CSI-RS set; and
transmitting (<NUM>) a CSI report that is based at least in part on the first CSI-RS set and the second CSI-RS set.