Beam index reporting based at least in part on precoded channel state information reference signals

Abstract

Various aspects of the disclosure generally relate to wireless communication. In some aspects, a base station can select a precoding matrix of an orthogonal beam. The base station can precode a channel state information reference signal (CSI-RS) transmitted to a user equipment (UE) using the precoding matrix of the orthogonal beam. The base station can receive, from the UE, one or more reports indicating one or more beam indices selected from beam indices associated with the precoding matrix of the orthogonal beam. Numerous other aspects are provided.

Description

[0001] Cross-reference to related applications

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 078,698, filed September 15, 2020, entitled “BEAM INDEX REPORTING BASED ATLEAST IN PART ON A PRECODED CHANNEL STATE INFORMATION REFERENCE SIGNAL,” and U.S. Non-Provisional Patent Application No. 17 / 447,543, filed September 13, 2021, entitled “BEAM INDEX REPORTING BASED AT LEAST IN PART ON A PRECODED CHANNEL STATE INFORMATION REFERENCE SIGNAL,” which are expressly incorporated herein by reference. Technical Field

[0003] This disclosure relates generally to wireless communication, and specifically to techniques and apparatus for beam index reporting based at least in part on precoded channel state information reference signals (CSI-RS). Background Technology

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunications services, such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems employ multiple access technologies that enable communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, and Long Term Evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard issued by the 3rd Generation Partnership Project (3GPP).

[0005] A wireless network may include one or more base stations that support communication between a user equipment (UE) or multiple UEs. A UE may communicate with a base station via downlink and uplink communication. "Downlink" (or "DL") refers to the communication link from the base station to the UE, and "uplink" (or "UL") refers to the communication link from the UE to the base station.

[0006] The aforementioned multiple access technologies have been adopted in various telecommunications standards to provide a common protocol that enables different UEs to communicate at the city, country, region, and / or global levels. New Radio (NR), often referred to as 5G, is a set of enhancements to the LTE mobile standard released by 3GPP. NR aims to better support mobile broadband internet access by: improving spectrum efficiency, reducing costs, improving service, utilizing new spectrum, and better integrating with other open standards that support beamforming, multiple-input multiple-output (MIMO) antenna technologies and carrier aggregation, including Orthogonal Frequency Division Multiplexing (OFDM) with Cyclic Prefix (CP) on the downlink, CP-OFDM and / or Single-Carrier Frequency Division Multiplexing (SC-FDM) (also known as Discrete Fourier Transform Spread Spectrum OFDM (DFT-s-OFDM)) on the uplink, and CP-OFDM on the uplink. Further improvements to LTE, NR, and other radio access technologies remain highly valuable as the demand for mobile broadband access continues to grow. Summary of the Invention

[0007] In some aspects, a method of wireless communication performed by a base station includes: selecting a precoding matrix of orthogonal beams; precoding a channel state information reference signal (CSI-RS) transmitted to a UE using the precoding matrix of orthogonal beams; and receiving from the UE one or more reports indicating one or more beam indices selected from beam indices associated with the precoding matrix of orthogonal beams.

[0008] In some aspects, a method of wireless communication performed by a UE includes: receiving CSI-RS precoded using a precoding matrix of orthogonal beams from a base station; selecting one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams; and sending one or more reports to the base station indicating the one or more beam indices.

[0009] In some aspects, a base station for wireless communication includes a memory and one or more processors coupled to the memory, the processors being configured to: select a precoding matrix of orthogonal beams; precode CSI-RS transmitted to a UE using the precoding matrix of orthogonal beams; and receive from the UE one or more reports indicating one or more beam indices selected from beam indices associated with the precoding matrix of orthogonal beams.

[0010] In some aspects, a UE for wireless communication includes a memory and one or more processors coupled to the memory, the processors being configured to: receive CSI-RS precoded using a precoding matrix of orthogonal beams from a base station; select one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams; and send one or more reports to the base station indicating the one or more beam indices.

[0011] In some aspects, a non-transitory computer-readable medium stores a set of instructions for wireless communication, the set of instructions including one or more instructions that, when executed by one or more processors of a base station, cause the base station to: select a precoding matrix of orthogonal beams; precode CSI-RS transmitted to a UE using the precoding matrix of orthogonal beams; and receive from the UE one or more reports indicating one or more beam indices selected from beam indices associated with the precoding matrix of orthogonal beams.

[0012] In some aspects, a non-transitory computer-readable medium stores a set of instructions for wireless communication, the set of instructions including one or more instructions that, when executed by one or more processors of the UE, cause the UE to: receive CSI-RS precoded using a precoding matrix of orthogonal beams from a base station; select one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams; and send one or more reports to the base station indicating one or more beam indices.

[0013] In some aspects, an apparatus for wireless communication includes: means for selecting a precoding matrix of orthogonal beams; means for precoding CSI-RS transmitted to a UE using the precoding matrix of orthogonal beams; and means for receiving from the UE one or more reports indicating one or more beam indices selected from beam indices associated with the precoding matrix of orthogonal beams.

[0014] In some aspects, an apparatus for wireless communication includes: means for receiving CSI-RS precoded using a precoding matrix of orthogonal beams from a base station; means for selecting one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams; and means for transmitting one or more reports indicating one or more beam indices to the base station.

[0015] The terms generally include methods, apparatus, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication equipment and / or processing systems, which are basically described herein with reference to the accompanying drawings and description.

[0016] The features and technical advantages of the examples according to this disclosure have been summarized rather broadly above in order to better understand the detailed description that follows. Additional features and advantages will be described below. The disclosed concepts and specific examples can be readily used as the basis for modifying or designing other structures for achieving the same purpose of this disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, their organization and operation, and associated advantages will be better understood from the following description when considered in conjunction with the accompanying drawings. Each of the drawings is provided for illustrative and descriptive purposes and is not intended to define limitations on the claims.

[0017] While aspects have been described in this disclosure by way of examples, those skilled in the art will understand that these aspects can be implemented in many different arrangements and scenarios. The techniques described herein can be implemented using different platform types, devices, systems, shapes, sizes, and / or package arrangements. For example, some aspects can be implemented via integrated chip embodiments or other devices based on non-modular components (e.g., end-user equipment, vehicles, communication equipment, computing devices, industrial equipment, retail / procurement equipment, medical devices, and / or artificial intelligence devices). Aspects can be implemented in chip-level components, modular components, non-modular components, non-chip-level components, device-level components, and / or system-level components. Devices incorporating the described aspects and features may include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals may include one or more components for analog and digital purposes (e.g., hardware components including antennas, radio frequency (RF) chains, power amplifiers, modulators, buffers, processors, interleavers, adders, and / or summers). The aspects described herein are intended to be practiced in a wide variety of devices, components, systems, distributed arrangements, and / or end-user equipment of different sizes, shapes, and configurations. Attached Figure Description

[0018] To gain a more detailed understanding of the features of this disclosure, reference can be made to several aspects for which a brief overview has been provided above, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain typical aspects of this disclosure and should not be considered as limiting its scope, as the description may acknowledge other equally valid aspects. The same reference numerals in different drawings may denote the same or similar elements.

[0019] Figure 1 This is a diagram illustrating an example of a wireless network according to this disclosure.

[0020] Figure 2 This is a diagram illustrating an example of a base station communicating with a user equipment (UE) in a wireless network according to the present disclosure.

[0021] Figure 3 This is a diagram illustrating an example of the Channel State Information (CSI) framework according to this disclosure.

[0022] Figure 4 This is a diagram illustrating an example of a CSI feedback timeline according to this disclosure.

[0023] Figure 5 This is a diagram illustrating an example of a beam index report associated with at least a precoded channel state information reference signal (CSI-RS) according to this disclosure.

[0024] Figure 6-7 This is a diagram illustrating an example process associated with a beam index report based at least in part on precoded CSI-RS, according to this disclosure.

[0025] Figure 8-9 This is a block diagram of an example device for wireless communication according to the present disclosure. Detailed Implementation

[0026] Various aspects of this disclosure will be described more fully below with reference to the accompanying drawings. However, this disclosure may be implemented in many different forms and should not be construed as limited to any particular structure or function presented throughout this disclosure. Rather, these aspects are provided to make this disclosure thorough and complete, and to fully convey the scope of this disclosure to those skilled in the art. Those skilled in the art will understand that the scope of this disclosure is intended to cover any aspect of the disclosure herein, whether implemented independently of or in combination with any other aspect of this disclosure. For example, any number of the aspects set forth herein may be used to implement an apparatus or practice. Furthermore, the scope of this disclosure is intended to cover an apparatus or method practiced using a structure, function, or structure and function other than or different from the aspects of this disclosure set forth herein. It should be understood that any aspect of the disclosure herein may be embodied by one or more elements of the claims.

[0027] Several aspects of a telecommunications system will now be described with reference to various devices and technologies. These devices and technologies will be described in detail below and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively, “elements”). These elements can be implemented using hardware, software, or a combination thereof. Whether these elements are implemented in hardware or software depends on the specific application and the design constraints on the overall system.

[0028] While the terms commonly associated with 5G or New Radio (NR) Radio Access Technology (RAT) may be used to describe the aspects herein, the aspects of this disclosure may be applied to other RATs, such as 3G RAT, 4G RAT and / or RATs after 5G (e.g., 6G).

[0029] Figure 1This diagram illustrates an example of a wireless network 100 according to the present disclosure. Among other examples, the wireless network 100 may be or may include elements of a 5G (e.g., NR) network and / or a 4G (e.g., Long Term Evolution (LTE)) network. The wireless network 100 may include one or more base stations 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d), user equipment (UE) 120 or multiple UEs 120 (shown as UE 120a, UE 120b, UE 120c, UE 120d, and UE 120e), and / or other network entities. Base station 110 is the entity that communicates with UE 120. Base station 110 (sometimes referred to as BS) may include, for example, an NR base station, an LTE base station, a Node B, an eNB (e.g., in 4G), a gNB (e.g., in 5G), an access point, and / or a Transmit / Receive Point (TRP). Each base station 110 may provide communication coverage for a specific geographic area. In the 3rd Generation Partnership Project (3GPP), the term "cell" can refer to the coverage area of ​​base station 110 and / or the base station subsystem serving that coverage area, depending on the context in which the term is used.

[0030] Base station 110 can provide communication coverage for macro cells, pico cells, femtocells, and / or another type of cell. A macro cell can cover a relatively large geographic area (e.g., a radius of several kilometers) and can allow unrestricted access for UE 120 with a service subscription. A pico cell can cover a relatively small geographic area and can allow unrestricted access for UE 120 with a service subscription. A femtocell can cover a relatively small geographic area (e.g., a home) and can allow restricted access for UE 120 associated with that femtocell (e.g., UE 120 in a Closed Subscriber Group (CSG)). Base station 110 for a macro cell can be referred to as a macro base station. Base station 110 for a pico cell can be referred to as a pico base station. Base station 110 for a femtocell can be referred to as a femtocell or a home base station. Figure 1 In the example shown, BS110a can be a macro base station of macro cell 102a, BS 110b can be a pico base station of pico cell 102b, and BS 110c can be a femto base station of femto cell 102c. A base station can support one or more (e.g., three) cells.

[0031] In some examples, the cell is not necessarily fixed, and the geographical area of ​​the cell can move depending on the location of the mobile base station 110 (e.g., a mobile base station). In some examples, base station 110 can use any suitable transport network to interconnect with each other and / or with one or more other base stations 110 or network nodes (not shown) in the wireless network 100 via various types of backhaul interfaces, such as direct physical connections or virtual networks.

[0032] Wireless network 100 may include one or more relay stations. A relay station is an entity that can receive data transmissions from an upstream station (e.g., base station 110 or UE 120) and transmit data transmissions to a downstream station (e.g., UE 120 or base station 110). A relay station may be a UE 120 capable of relaying transmissions for other UE 120s. Figure 1 In the example shown, BS 110d (e.g., a relay base station) can communicate with BS 110a (e.g., a macro base station) and UE 120d to facilitate communication between BS 110a and UE 120d. The base station 110 for relay communication can be referred to as a relay station, relay base station, repeater, etc.

[0033] Wireless network 100 can be a heterogeneous network, comprising different types of base stations 110, such as macro base stations, pico base stations, femto base stations, relay base stations, etc. These different types of base stations 110 can have different transmit power levels, different coverage areas, and / or different effects on interference in wireless network 100. For example, macro base stations can have high transmit power levels (e.g., 5 to 40 watts), while pico base stations, femto base stations, and relay base stations can have lower transmit power levels (e.g., 0.1 to 2 watts).

[0034] Network controller 130 can be coupled to or communicate with a group of base stations 110, and can provide coordination and control for these base stations 110. Network controller 130 can communicate with base stations 110 via backhaul communication links. Base stations 110 can communicate with each other directly or indirectly via wireless or wired backhaul communication links.

[0035] UE 120 may be distributed throughout the wireless network 100, and each UE 120 may be fixed or mobile. UE 120 may include, for example, access terminals, terminals, mobile stations, and / or subscriber units. UE 120 may be a cellular phone (e.g., a smartphone), 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, a biometric device, a wearable device (e.g., a smartwatch, smart clothing, smart glasses, a smart wristband, smart jewelry (e.g., a smart ring or smart bracelet)), an entertainment device (e.g., a music device, a video device, and / or a satellite radio), a vehicle component or sensor, a smart meter / sensor, industrial manufacturing equipment, a GPS device, and / or any other suitable device configured to communicate via a wireless medium.

[0036] Some UEs 120 may be considered Machine-Type Communication (MTC) or Evolved or Enhanced Machine-Type Communication (eMTC) UEs. MTC UEs and / or eMTC UEs may include, for example, robots, drones, remote devices, sensors, meters, monitors, and / or location tags, which can communicate with a base station, another device (e.g., a remote device), or some other entity. Some UEs 120 may be considered Internet of Things (IoT) devices, and / or may be implemented as NB-IoT (Narrowband IoT) devices. Some UEs 120 may be considered client devices. UEs 120 may be included within a housing that houses the components of the UE 120, such as processor components and / or memory components. In some examples, the processor components and memory components may be coupled together. For example, the processor components (e.g., one or more processors) and memory components (e.g., memory) may be operatively coupled, communicatively coupled, electronically coupled, and / or electrically coupled.

[0037] Typically, any number of wireless networks 100 can be deployed in a given geographical area. Each wireless network 100 can support a specific RAT and can operate on one or more frequencies. A RAT can be referred to as a radio technology, air interface, etc. A frequency can be referred to as a carrier, channel, etc. Each frequency can support a single RAT in a given geographical area to avoid interference between wireless networks using different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0038] In some examples, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly using one or more sidelink channels (e.g., without using base station 110 as a medium for communication with each other). For example, UE 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocols (e.g., which may include vehicle-to-vehicle (V2V) protocols, vehicle-to-infrastructure (V2I) protocols, or vehicle-to-pedestrian (V2P) protocols) and / or mesh networks. In such examples, UE 120 may perform scheduling operations, resource selection operations, and / or other operations performed by base station 110 as described elsewhere herein.

[0039] Devices in Wireless Network 100 can communicate using the electromagnetic spectrum, which can be subdivided into various categories, bands, channels, etc., by frequency or wavelength. For example, devices in Wireless Network 100 can communicate using one or more operating frequency bands. In 5G NR, two initial operating frequency bands have been designated as frequency range designations FR1 (410MHz–7.125GHz) and FR2 (24.25GHz–52.6GHz). It should be understood that although a portion of FR1 is greater than 6GHz, FR1 is often (interchangeably) referred to as the “below 6GHz” band in various documents and articles. Similar naming issues sometimes arise with FR2; although it differs from the Extremely High Frequency (EHF) band (30GHz–300GHz) designated as a “millimeter wave” band by the International Telecommunication Union (ITU), FR2 is generally (interchangeably) referred to as the “millimeter wave” band in documents and articles.

[0040] The frequencies between FR1 and FR2 are generally referred to as intermediate frequency (IF) frequencies. Recent 5G NR studies have identified the operating bands for these IF frequencies as the frequency range name FR3 (7.125 GHz – 24.25 GHz). Bands falling within FR3 can inherit FR1 and / or FR2 characteristics, thus effectively extending the features of FR1 and / or FR2 to the IF frequencies. Furthermore, higher frequency bands are currently being explored to extend 5G NR operation above 52.6 GHz. For example, three higher operating frequency bands have been identified as the frequency range names FR4a or FR4-1 (52.6 GHz – 71 GHz), FR4 (52.6 GHz – 114.25 GHz), and FR5 (114.25 GHz – 300 GHz). Each of these higher frequency bands belongs to the EHF band.

[0041] Remembering the examples above, unless otherwise stated, it should be understood that the terms "below 6 GHz," etc., if used herein, can broadly refer to frequencies below 6 GHz, which may be within FR1, or may include intermediate frequency band frequencies. Furthermore, unless otherwise stated, it should be understood that the terms "millimeter wave," etc., if used herein, can broadly refer to frequencies that may include intermediate frequency band frequencies, which may be within FR2, FR4, FR4-a, or FR4-1 and / or FR5, or may be within the EHF band. It is anticipated that the frequencies included in these operating frequency bands (e.g., FR1, FR2, FR3, FR4, FR4-a, FR4-1, and / or FR5) can be modified, and the techniques described herein are applicable to those modified frequency ranges.

[0042] As mentioned above, Figure 1 This is provided as an example. Other examples may differ from those provided. Figure 1 As described.

[0043] Figure 2 This is a diagram illustrating an example 200 of a base station 110 communicating with a UE 120 in a wireless network 100 according to the present disclosure. The base station 110 may be equipped with a set of antennas 234a to 234t, such as T antennas (T≥1). The UE 120 may be equipped with a set of antennas 252a to 252r, such as R antennas (R≥1).

[0044] At base station 110, transmitting processor 220 can receive data destined for UE 120 (or a group of UEs 120) from data source 212. Transmitting processor 220 can select one or more modulation and coding schemes (MCS) for UE 120, at least in part, based on one or more Channel Quality Indicators (CQIs) received from UE 120. Base station 110 can process (e.g., encode and modulate) the data for UE 120, at least in part, based on the selected MCS(s) for UE 120, and can provide data symbols for UE 120. Transmitting processor 220 can process system information (e.g., for Semi-Static Resource Partitioning Information (SRPI)) and control information (e.g., CQI requests, grants, and / or upper-layer signaling), and provide overhead symbols and control symbols. Transmitting processor 220 can generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS) or demodulation reference signals (DMRS)) and synchronization signals (e.g., primary synchronization signal (PSS) or secondary synchronization signal (SSS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 can perform spatial processing (e.g., precoding, if applicable) on data symbols, control symbols, overhead symbols, and / or reference symbols, and can provide a set of output symbol streams (e.g., T output symbol streams) to a corresponding set of modems 232 (e.g., T modems) (shown as modems 232a to 232t). For example, each output symbol stream can be provided to a modulator component (shown as MOD) of modem 232. Each modem 232 can use its respective modulator component to process its respective output symbol stream (e.g., for OFDM) to obtain an output sample stream. Each modem 232 can also use its respective modulator component to process (e.g., convert to analog, amplify, filter, and / or up-convert) the output sample stream to obtain a downlink signal. Modems 232a to 232t can transmit a set of downlink signals (e.g., T downlink signals) via a corresponding set of antennas 234 (e.g., T antennas) (shown as antennas 234a to 234t).

[0045] At UE 120, a set of antennas 252 (shown as antennas 252a to 252r) can receive downlink signals from base station 110 and / or other base stations 110, and can provide a set of received signals (e.g., R received signals) to a set of modems 254 (e.g., R modems) (shown as modems 254a to 254r). For example, each received signal can be provided to a demodulator component (shown as DEMOD) of modem 254. Each modem 254 can use its respective demodulator component to condition (e.g., filter, amplify, downconvert, and / or digitize) the received signal to obtain an input sample. Each modem 254 can use the demodulator component to further process the input sample (e.g., for OFDM) to obtain a received symbol. MIMO detector 256 can obtain the received symbols from modem 254, perform MIMO detection on the received symbols if applicable, and provide the detected symbols. The receiver processor 258 can process (e.g., demodulate and decode) the detected symbols, provide decoded data of the UE 120 to the data sink 260, and provide decoded control information and system information to the controller / processor 280. The term "controller / processor" can refer to one or more controllers, one or more processors, or a combination thereof. The channel processor can determine parameters such as the Reference Signal Received Power (RSRP) parameter, the Received Signal Strength Indicator (RSSI) parameter, the Reference Signal Received Quality (RSRQ) parameter, and / or the CQI parameter. In some examples, one or more components of the UE 120 may be included in the housing 284.

[0046] Network controller 130 may include communication unit 294, controller / processor 290, and memory 292. Network controller 130 may include one or more devices, such as those in a core network. Network controller 130 may communicate with base station 110 via communication unit 294.

[0047] One or more antennas (e.g., antennas 234a to 234t and / or antennas 252a to 252r) may include or be included therein one or more antenna panels, one or more antenna groups, one or more collections of antenna elements, and / or one or more antenna arrays. Antenna panels, antenna groups, collections of antenna elements, and / or antenna arrays may include one or more antenna elements (within a single housing or multiple housings), collections of coplanar antenna elements, collections of non-coplanar antenna elements, and / or be coupled to one or more transmitting and / or receiving components (such as...). Figure 2 One or more antenna elements (one or more components).

[0048] On the uplink, at UE 120, the transmit processor 264 can receive and process data from data source 262 and control information from controller / processor 280 (e.g., for reporting including RSRP, RSSI, RSRQ, and / or CQI). The transmit processor 264 can generate reference symbols for one or more reference signals. If applicable, the symbols from the transmit processor 264 can be pre-encoded by the TX MIMO processor 266, further processed by the modem 254 (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to base station 110. In some examples, the modem 254 of UE 120 may include a modulator and demodulator. In some examples, UE 120 includes a transceiver. The transceiver may include any combination of antenna(s) 252, modem(s) 254, MIMO detector 256, receive processor 258, transmit processor 264, and / or TX MIMO processor 266. The processor (e.g., controller / processor 280) and memory 282 can use a transceiver to perform any aspect of the methods described herein (e.g., reference...). Figure 5-9 ).

[0049] At base station 110, uplink signals from UE 120 and / or other UEs may be received by antenna 234, processed by modem 232 (e.g., demodulator component of modem 232, shown as DEMOD), detected by MIMO detector 236 (if applicable), and further processed by receive processor 238 to obtain decoded data and control information transmitted by UE 120. Receive processor 238 may provide the decoded data to data sink 239 and the decoded control information to controller / processor 240. Base station 110 may include communication unit 244 and may communicate with network controller 130 via communication unit 244. Base station 110 may include scheduler 246 for scheduling one or more UEs 120 for downlink and / or uplink communication. In some examples, modem 232 of base station 110 may include modulator and demodulator. In some examples, base station 110 includes transceiver. The transceiver may include any combination of antenna(s) 234, modem(s) 232, MIMO detector 236, receive processor 238, transmit processor 220, and / or TX MIMO processor 230. The processor (e.g., controller / processor 240) and memory 242 may be used with the transceiver to perform any aspect of the methods described herein (e.g., reference...). Figure 5-9 ).

[0050] The controller / processor 240 of base station 110, the controller / processor 280 of UE 120 and / or Figure 2Any other component(s) may perform one or more techniques associated with beam index reporting, at least in part, based on a precoded channel state information reference signal (CSI-RS), as described in more detail elsewhere herein. For example, the controller / processor 240 of base station 110, the controller / processor 280 of UE 120, and / or Figure 2 Any other component(s) can perform or direct, for example Figure 6 Process 600 Figure 7 The operation of process 700 and / or other processes described herein. Memory 242 and memory 282 may store data and program code for base station 110 and UE 120, respectively. In some examples, memory 242 and / or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and / or program code) for wireless communication. For example, when one or more instructions are executed by one or more processors of base station 110 and / or UE 120 (e.g., directly, or after compilation, transformation, and / or interpretation), they may cause one or more processors, UE 120, and / or base station 110 to perform or direct, for example... Figure 6 Process 600 Figure 7 The operation of process 700 and / or other processes described herein. In some examples, execution instructions may include run instructions, transformation instructions, compilation instructions, and / or interpretation instructions, etc.

[0051] In some aspects, a base station (e.g., base station 110) may include components for selecting a precoding matrix of orthogonal beams, components for precoding CSI-RS transmitted to a UE using the precoding matrix of orthogonal beams, and / or components for receiving from the UE one or more reports indicating the selection of one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams. In some aspects, these components may include combinations of Figure 2 One or more components of the described base station 110, such as antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232 and / or antenna 234.

[0052] In some aspects, the UE (e.g., UE 120) may include components for receiving CSI-RS precoded using a precoding matrix of orthogonal beams from a base station, components for selecting one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams, and / or components for sending one or more reports indicating one or more beam indices to the base station. In some aspects, these components may include combinations of Figure 2One or more components of the described UE 120, such as controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256 and / or receive processor 258.

[0053] Although Figure 2 The blocks are shown as different components, but the functions described above for the blocks can be implemented in a single hardware, software, or combined component, or in various combinations of components. For example, the functions described for the transmit processor 264, receive processor 258, and / or TX MIMO processor 266 can be executed by or under the control of the controller / processor 280.

[0054] As mentioned above, Figure 2 This is provided as an example. Other examples may differ from those provided. Figure 2 As described.

[0055] Figure 3 This is a diagram illustrating Example 300 of the Channel State Information (CSI) framework according to this disclosure.

[0056] As shown by reference numeral 302 in the attached figure, the UE can transmit a sounding reference signal (SRS) to the base station in the uplink. The base station can perform channel estimation to estimate the channel between the base station and the UE, at least in part, based on the SRS received from the UE. The base station can select a precoder based at least in part on the channel estimation. The base station can apply the precoder to downlink transmissions to the UE.

[0057] As shown by reference numeral 304 in the attached figure, the base station can send CSI-RS to the UE in the downlink. The UE can perform channel estimation to estimate the channel between the UE and the base station, at least in part, based on the CSI-RS received from the base station. In other words, the UE can perform channel estimation to identify the CSI associated with the channel between the UE and the base station. The UE can send a CSI report (or CSI feedback) to the base station. The base station can select a precoder, at least in part, based on the CSI report received from the UE. The base station can apply the precoder to downlink transmissions to the UE.

[0058] As mentioned above, Figure 3 This is provided as an example. Other examples may differ from those provided. Figure 3 As described.

[0059] Figure 4 This is a diagram illustrating Example 400 of the CSI feedback timeline according to this disclosure.

[0060] like Figure 4As shown, the evaluation of the CSI feedback timeline can include at least three values. The Z value defines the number of symbols between the last Physical Downlink Control Channel (PDCCH) symbol and the first uplink transmitted symbol. The Z' value defines the number of symbols between the end of the CSI-RS symbol and the first uplink transmitted symbol. The KB value defines the number of symbols between the PDCCH and beam switching (for millimeter wave cases). The Z and Z' values ​​can be configured according to latency requirements. For example, the Z and Z' values ​​can be configured by the base station for low-latency, medium-latency, and / or high-latency scenarios.

[0061] As mentioned above, Figure 4 This is provided as an example. Other examples may differ from those provided. Figure 4 As described.

[0062] The UE can determine the CSI feedback associated with the channel between the UE and the base station. CSI feedback can be included in the CSI report sent from the UE to the base station. CSI feedback can support various antenna configurations. When the UE is configured with four or more antenna ports, the CSI feedback can be at least partially based on a dual-stage codebook. An example of a dual-stage codebook can be a precoding matrix indicator (PMI) codebook. The PMI codebook can be associated with a precoder structure, which can be defined by W = W1W2. In other words, the precoder structure (W) can be the product of W1 and W2, where W1 can represent the long-term or wideband attributes of the channel, and W2 can represent the short-term or subband (e.g., a subband comprising a set of resource blocks) attributes of the channel. It can be based on... Let W be defined, where B can correspond to L oversampled two-dimensional discrete Fourier transform (DFT) beams, where L is a positive integer.

[0063] The CSI feedback timeline can involve the UE selecting a set of beams given the precoding structure of the PMI codebook. The search complexity W1 and W2 for beam selection can increase depending on the number of antenna ports and layers, and may lead to increased power consumption at the UE. Furthermore, the increased search complexity may delay the reporting time of CSI feedback (e.g., the base station may wait for an increased period of time to receive CSI feedback from the UE).

[0064] For example, the search complexity of W1 computation performed at the UE could be an O1, O2, N1, N2 beam search, where O1 and O2 indicate DFT oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions. In the case of 32 antenna ports, an O1, O2, N1, N2 beam search could correspond to a 256-beam search, where O1 and O2 equal 4. In this example, a 256-beam search might increase complexity and power consumption at the UE and lead to an increase in beam reporting time.

[0065] In various aspects of the techniques and apparatus described herein, a base station can precode the CSI-RS transmitted to a UE using a set of orthogonal beams. The orthogonal set of beams can be a subset of multiple possible beams. For example, the base station can precode the CSI-RS using a subset of N1, N2 orthogonal DFT beams. The UE can perform W1 calculations at least partially based on a subset of N1, N2 orthogonal DFT beams, as opposed to performing W1 calculations at least partially based on O1, O2, N1, N2 orthogonal DFT beams. Precoding the CSI-RS using a subset of N1, N2 orthogonal beams reduces complexity at the UE, reduces power consumption at the UE, and reduces the CSI feedback timeline used to calculate and transmit the CSI report including the calculated W1.

[0066] In some respects, a reduced CSI feedback timeline can lead to a reduced Z' value. For example, when the UE performs W1 calculations with reduced complexity and power consumption, the number of symbols between the end of the CSI-RS symbol defined by the Z' value and the first uplink transmitted symbol can be reduced. Since the UE can report the calculated W1 to the base station within the reduced timeframe, the UE can also begin uplink transmissions within the reduced timeframe.

[0067] In some respects, multiple possible beams (F) can be derived from F = kron(DFT). O1N1 | N1 columns DFT O2N2 | N2 columns The definition is as follows: F can be a matrix of size O1, O2, N1, N2 multiplied by N1, N2, where kron denotes the Kronecker product. Furthermore, DFT... O1N1 | N1 columns It can be equal to: And DFT O2N2 | N2 columns It can be equal to:

[0068]

[0069] For matrix F, starting from a given row, shifting every O1 = O2 = O = 4 columns results in orthogonality between them. In other words, starting from a given column, columns N1 and N2 separated by four columns can be orthogonal to other columns N1 and N2 separated by four columns. For example, N2 can be one, O2 can be one, N2 can be four, and O1 can be four. The first set of orthogonal beams can correspond to rows 0, 4, 8, 12… of matrix F. The second set of orthogonal beams can correspond to rows 1, 5, 9, 13… of matrix F. The third set of orthogonal beams can correspond to rows 2, 6, 10, 14… of matrix F. The fourth set of orthogonal beams can correspond to rows 3, 7, 11, 15… of matrix F. The next set of orthogonal beams can be a repetition of the first set, and so on. FFFFF

[0070] In some respects, a matrix can be divided into O1 and O2 submatrices, where each submatrix (or subset) can consist of N1 and N2 orthogonal beams. In other words, each submatrix can consist of a set of orthogonal beams. For example, a submatrix can be... Labels, where i = 1, 2, ..., O1O2, and For i = j, δ ij =1, otherwise zero. A precoder used for precoding 2N1N2 ports can be... and For i = j, δ ij =1. Here, It can be an N1N2×N1N2 matrix and can be obtained from matrix F.

[0071] In some respects, the base station can use a subset (or submatrix) of orthogonal beams to precode the CSI-RS transmitted to the UE. Instead of performing W1 calculations at least partially based on multiple beams (e.g., all beams) included in matrix F, the UE can perform W1 calculations at least partially based on a subset of orthogonal beams. Precoding the CSI-RS using a subset of orthogonal beams reduces complexity at the UE, reduces the amount of power consumed at the UE, and reduces the CSI feedback timeline used to calculate and transmit the CSI report including the calculated W1.

[0072] Figure 5 This is a diagram illustrating example 500 associated with a beam index report based at least in part on precoded CSI-RS, according to this disclosure. Figure 5 As shown, Example 500 includes communication between a base station (e.g., base station 110) and a UE (e.g., UE 120). In some aspects, the base station and the UE may be included in a wireless network such as wireless network 100. The base station and the UE may communicate on a radio access link, which may include an uplink and a downlink.

[0073] As shown by reference numeral 502 in the attached figure, the base station can select the precoding matrix of the orthogonal beam (e.g., submatrix F). i The precoding matrix for orthogonal beams can be a subset or submatrix of multiple beams (e.g., all beams) included in matrix F. Matrix F can have dimensions at least partially based on O1, O2, N1, and N2, where O1 and O2 indicate Discrete Fourier Transform (DFT) oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions. Matrix F can be partitioned to form the precoding matrix for orthogonal beams. The base station can use the precoding matrix for orthogonal beams to precode CSI-RS for transmission to the UE.

[0074] In some respects, the base station can randomly select the precoding matrix (F) of the orthogonal beams from matrix F. i The base station can blindly select the precoding matrix of the orthogonal beams without using information describing the channel between the base station and the UE. The base station can select the precoding matrix of the orthogonal beams (F... i ), such that i is randomly generated from i = 1, 2, ..., O1O2. The base station can use a blind-selected orthogonal beam precoding matrix to precode CSI-RS.

[0075] In some respects, the base station can select the precoding matrix (F) of the orthogonal beams based at least in part on the SRS received from the UE. i For example, a base station can receive SRS from a UE in the uplink. The UE can use SRS with antenna switching capabilities to probe the uplink channel, which can be obtained for downlink CSI in a reciprocal time-division duplex (TDD) system. The base station can determine the precoding matrix of the orthogonal beams, at least in part, based on the SRS, by calculating the orthogonal beams that can lead to performance improvements at the UE, and the precoding matrix of the orthogonal beams can be used to precode the CSI-RS.

[0076] In some respects, orthogonal patterns of O1O2 for N1N2 size beams may be available. The search complexity at the base station for calculating orthogonal beams that can lead to performance improvements at the UE can be based at least in part on signal-to-noise ratio (SNR) and / or average spectral efficiency (SPEF) metrics.

[0077] In some respects, the base station can identify individual beams, at least partially, based on SRS, where such individual beams can be expected to lead to performance improvements at the UE. The base station can map individual beams to specific beam indices i. The base station can identify the precoding matrix (F) of orthogonal beams. i The matrix includes a specific beam index i associated with a single beam.

[0078] In some respects, the base station can select the precoding matrix of orthogonal beams based at least in part on the last beam index indicated in one or more last reports from the UE. For example, the UE may have previously reported the “best” beam index i. 1,1 i 1,2 This may correspond to a beam that generates increased energy at the antenna port compared to other beams. The base station can use the i received from the UE 1,1 i 1,2 The final report's beam index determines the inclusion of i 1,1 i 1,2 The precoding matrix for the orthogonal beams. Including i 1,1 i 1,2 The precoding matrix of a pair of orthogonal beams can be derived from the precoder submatrix F. l This indicates that it can be used for precoding CSI-RS.

[0079] In some respects, the base station can select the precoding matrix of orthogonal beams based at least in part on the most frequently selected beam index among M last beam indices indicated from one or more last reports from the UE, where M is a positive integer. For example, the base station can use i received from the UE 1,1 i 1,2 The M last reported beam indices determine the inclusion of i 1,1 i 1,2 The most frequently chosen precoding matrix for orthogonal beams. Including i 1,1 i 1,2 The most frequently chosen precoding matrix for a pair of orthogonal beams can be derived from the precoder submatrix F. l This indicates that it can be used for precoding CSI-RS.

[0080] For example, when M equals 5, i 1,1 i 1,2 The beam index of the first and last reported beam can be associated with the precoder submatrix F1, i 1,1 i 1,2 The second, final reported beam index can be associated with the precoder submatrix F2, i 1,1 i 1,2 The third and final reported beam index can be associated with the precoder submatrix F3, i 1,1 i 1,2 The fourth and final reported beam index can be associated with the precoder submatrix F1, i 1,1 i 1,2 The fifth and final reported beam index can be associated with the precoder submatrix F1. In this example, F1 can be a matrix including i 1,1 i 1,2The most frequently selected precoding matrix for the orthogonal beam, and F1 can be used to precode CSI-RS.

[0081] In some respects, a base station may send an indication of M via Radio Resource Control (RRC) signaling, Media Access Control (MAC) control element (CE), or Downlink Control Information (DCI).

[0082] As shown by reference numeral 504 in the attached figure, the base station can transmit precoded CSI-RS to the UE. The base station can also transmit beam indices (e.g., index i, where i = 1, 2, ..., O1O2, and F) associated with the precoding matrix of the orthogonal beams used for precoding the CSI-RS. i F j =Iδ ij For i = j, δ ij =1).

[0083] In some respects, when the base station selects the precoding matrix of orthogonal beams based at least in part on the last beam index indicated from one or more last reports from the UE, and / or when the base station selects the precoding matrix of orthogonal beams based at least in part on the beam index most frequently selected among M last beam indices indicated from one or more last reports from the UE, the base station may not report the matrix precoder index or the beam index (e.g., i...). 1,1 i 1,2 In these cases, the UE can determine whether the base station is using matrix precoder indexing or beam indexing (e.g., i...). 1,1 i 1,2 ).

[0084] In some respects, the base station can dynamically notify the UE via RRC signaling, MAC CE and / or DCI that the precoding matrix of orthogonal beams can be selected at least in part based on the last beam index or the beam index selected most frequently from the M last beam indices.

[0085] As shown by reference numeral 506 in the attached figure, the UE can estimate the channel between the UE and the base station. For example, the UE can estimate the precoded channel HF based at least in part on precoded CSI-RS (e.g., CSI-RS pilots) received from the base station. i The UE can receive beam indices (e.g., index i, where i = 1, 2, ..., O1O2, and F) associated with the precoding matrix of the orthogonal beams used for precoding CSI-RS. i F j =Iδ ij For i = j, δ ij =1). In addition, the UE can perform W1 calculation at least in part based on the beam index received from the base station.

[0086] In some respects, the UE can select one or more beam indices from the beam indices associated with the precoding matrix of orthogonal beams. For example, the UE can identify the "optimal" beam index (e.g., i... 1,1 i 1,2 This can correspond to a beam that generates increased energy at the antenna port compared to other beams. The UE can identify the beam index at least in part based on the beam index received from the base station.

[0087] As shown by reference numeral 508 in the attached figure, the UE can generate a first report with the selected beam index. The first report may include some or all information about the W1 precoding matrix, and / or the first report may include some or all information for inclusions in a second report. The first report may indicate the broadband beam i 1,1 i 1,2 or broadband beam 1,1 i 1,2 and i 1,3 For example, in the first report, the UE can indicate i 1,1 i 1,2 (It can correspond to the index of the optimal beam in two-dimensional space) and i 1,3 (It can represent relative to i) 1,1 i 1,2 The defined beam is used to obtain the offsets k1, k2 of the second-layer beam.

[0088] In some respects, the UE may send the first report on the first uplink license allocated after the period of receiving CSI-RS (e.g., the symbol duration defined by the Z0′ value). The UE may be configured to send the first report at least in part based on RRC signaling or MAC CE received from the base station. The UE may receive RRC signaling or MAC CE at least a defined number of symbols prior to the first report.

[0089] As shown by reference numeral 510 in the attached figure, the UE can generate a second report with an updated beam index. The updated beam index can be updated relative to the selected beam index included in the first report. The second report may include some or all information about the w1 precoding matrix, information about the W2 precoder, and other information such as channel rank information, channel quality indicator (CQI), and / or RSRP. The second report may indicate the updated wideband beam i 1,1 i 1,2 or newer broadband beams i 1,1 i 1,2 and i 1,3 For example, in the second report, the UE can indicate the updated i 1,1i 1,2 (It can correspond to the index of the optimal beam in two-dimensional space) and i 1,3 (It can represent relative to i) 1,1 i 1,2 The defined beam is used to obtain the offsets k1, k2 of the second-layer beam.

[0090] In some respects, the UE may send a second report on a second uplink license allocated after the period of receiving CSI-RS (e.g., the symbol duration defined by the Z1′ value). The UE may be configured to send the second report at least in part based on RRC signaling or MAC CE received from the base station. The UE may receive RRC signaling or MAC CE at least a defined number of symbols prior to the second report.

[0091] In some respects, the aforementioned techniques can improve downlink data precoding performed by the base station because the first report can include an updated wideband precoder to be used for downlink data precoding until a complete CSI report is completed at the UE. Furthermore, if the UE is a low-capacity UE (e.g., a low-power UE), the UE can relay the precoded CSI-RS to obtain the W2-selected precoder and complete the CSI report, which can save modem cycles at the UE.

[0092] As mentioned above, Figure 5 This is provided as an example. Other examples may differ from those provided. Figure 5 As described.

[0093] Figure 6 This is a diagram illustrating an example process 600 performed by a base station, for example, according to this disclosure. Example process 600 is an example of a base station (e.g., base station 110) performing operations associated with beam index reporting, at least in part based on precoded CSI-RS.

[0094] like Figure 6 As shown, in some aspects, process 600 may include selecting a precoding matrix for orthogonal beams (block 610). For example, a base station (e.g., using transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller / processor 240, memory 242 and / or scheduler 246) may select a precoding matrix for orthogonal beams as described above.

[0095] like Figure 6As further shown, in some aspects, process 600 may include precoding the CSI-RS transmitted to the UE using a precoding matrix of orthogonal beams (block 620). For example, as described above, the base station (e.g., using transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller / processor 240, memory 242 and / or scheduler 246) may use a precoding matrix of orthogonal beams to precode the CSI-RS transmitted to the UE.

[0096] like Figure 6 As further illustrated, in some aspects, process 600 may include receiving from the UE one or more reports (block 630) indicating the selection of one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams. For example, a base station (e.g., using antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller / processor 240, and / or memory 242) may receive one or more reports from the UE indicating the selection of one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams, as described above.

[0097] Process 600 may include additional aspects, such as any single aspect or any combination of aspects described below, and / or in conjunction with one or more other processes described elsewhere herein.

[0098] In a first aspect, process 600 includes partitioning a matrix having dimensions at least partially based on O1, O2, N1, and N2 to form a precoding matrix for orthogonal beams, wherein O1 and O2 indicate DFT oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions.

[0099] In the second aspect, alone or in combination with the first aspect, the precoding matrix for selecting orthogonal beams includes randomly selecting precoding matrices for orthogonal beams from matrices having dimensions at least partially based on O1, O2, N1, and N2.

[0100] In a third aspect, either alone or in combination with one or more of the first and second aspects, the selection of the precoding matrix for orthogonal beams includes selecting the precoding matrix for orthogonal beams based at least in part on the probe reference signal received from the UE.

[0101] In the fourth aspect, either alone or in combination with one or more of the first to third aspects, the selection of the precoding matrix for orthogonal beams includes selecting the precoding matrix for orthogonal beams based at least in part on the last beam index indicated in one or more last reports from the UE.

[0102] In the fifth aspect, either alone or in combination with one or more of the first to fourth aspects, the precoding matrix for selecting orthogonal beams includes selecting the precoding matrix for orthogonal beams based at least in part on the beam index most frequently selected among M last beam indices indicated from one or more last reports from the UE, where M is a positive integer.

[0103] In the sixth aspect, either alone or in combination with one or more of the first to fifth aspects, process 600 includes sending an instruction for M to the UE via RRC signaling, MAC CE, or DCI.

[0104] In the seventh aspect, either alone or in combination with one or more of the first to sixth aspects, one or more reports include a first report indicating one or more beam indices selected by the UE.

[0105] In the eighth aspect, either alone or in combination with one or more of the first to seventh aspects, one or more reports include a second report indicating one or more updated beam indices selected by the UE.

[0106] In the ninth aspect, either alone or in combination with one or more of the first to eighth aspects, process 600 includes sending to the UE a beam index associated with a precoding matrix for precoding orthogonal beams of CSI-RS.

[0107] although Figure 6 An example block of process 600 is shown, but in some respects, process 600 may include more than Figure 6 The blocks described in the diagram may be more blocks, fewer blocks, different blocks, or blocks with different arrangements. Additionally or alternatively, two or more blocks of process 600 may be executed in parallel.

[0108] Figure 7 This is a diagram illustrating an example procedure 700 performed by a UE, for example, according to this disclosure. Example procedure 700 is an example of a UE (e.g., UE 120) performing operations associated with beam index reporting, at least in part, based on precoded CSI-RS.

[0109] like Figure 7 As shown, in some aspects, process 700 may include receiving CSI-RS precoded using a precoding matrix with orthogonal beams from a base station (block 710). For example, the UE (e.g., using antenna 234, demodulator 232, MIMO detector 236, receiver processor 238, controller / processor 240 and / or memory 242; and / or using antenna 252, demodulator 254, MIMO detector 256, receiver processor 258, controller / processor 280 and / or memory 282) may receive CSI-RS precoded using a precoding matrix with orthogonal beams from a base station, as described above.

[0110] like Figure 7 As further illustrated, in some aspects, process 700 may include selecting one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams (block 720). For example, the UE (e.g., using transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller / processor 240, memory 242 and / or scheduler 246; and / or using antenna 252, demodulator 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, modulator 254, controller / processor 280 and / or memory 282) may select one or more beam indices from the beam indices associated with the precoding matrix of orthogonal beams, as described above.

[0111] like Figure 7 As further illustrated, in some aspects, process 700 may include sending one or more reports (block 730) to the base station indicating one or more beam indices. For example, the UE (e.g., using transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, controller / processor 240, memory 242 and / or scheduler 246; and / or using antenna 252, transmit processor 264, TX MIMO processor 266, modulator 254, controller / processor 280 and / or memory 282) may send one or more reports indicating one or more beam indices to the base station, as described above.

[0112] Process 700 may include additional aspects, such as any single aspect or any combination of aspects described below, and / or in conjunction with one or more other processes described elsewhere herein.

[0113] In the first aspect, the precoding matrix of the orthogonal beam is a submatrix of a matrix having dimensions at least partially based on O1, O2, N1, and N2, where O1 and O2 indicate DFT oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions.

[0114] In the second aspect, either alone or in combination with the first aspect, a precoding matrix for orthogonal beams is randomly selected from a matrix having dimensions at least partially based on O1, O2, N1, and N2.

[0115] In a third aspect, either alone or in combination with one or more of the first and second aspects, process 700 includes transmitting a probe reference signal to a base station, wherein the precoding matrix of the orthogonal beam is selected based at least in part on the probe reference signal.

[0116] In the fourth aspect, the precoding matrix of orthogonal beams is selected, either alone or in combination with one or more of the first to third aspects, at least in part based on the last beam index indicated in one or more last reports from the UE.

[0117] In the fifth aspect, the precoding matrix of orthogonal beams is selected, either alone or in combination with one or more of the first to fourth aspects, at least in part based on the beam index most frequently selected among the M last beam indices indicated from one or more last reports from the UE, where M is a positive integer.

[0118] In the sixth aspect, either alone or in combination with one or more of the first to fifth aspects, process 700 includes receiving an indication of M from the base station via RRC signaling, MAC CE, or DCI.

[0119] In the seventh aspect, alone or in combination with one or more of the first to sixth aspects, one or more reports include a first report indicating one or more beam indices.

[0120] In the eighth aspect, either alone or in combination with one or more of the first to seventh aspects, process 700 includes selecting one or more updated beam indices, which are updates to one or more beam indices indicated in the first report, wherein one or more reports include a second report indicating one or more updated beam indices.

[0121] In the ninth aspect, either alone or in combination with one or more of the first to eighth aspects, process 700 includes receiving from the base station a beam index associated with a precoding matrix for precoding orthogonal beams of CSI-RS.

[0122] although Figure 7 An example block of process 700 is shown, but in some respects, process 700 may include more than Figure 7 The blocks described in the diagram may include more blocks, fewer blocks, different blocks, or blocks with different arrangements. Additionally or alternatively, two or more blocks of process 700 may be executed in parallel.

[0123] Figure 8This is a block diagram of an example device 800 for wireless communication. Device 800 may be a base station, or a base station may include device 800. In some aspects, device 800 includes a receiving component 802 and a transmitting component 804, which can communicate with each other (e.g., via one or more buses and / or one or more other components). As shown, device 800 can use the receiving component 802 and the transmitting component 804 to communicate with another device 806 (such as a UE, a base station, or another wireless communication device). As further shown, device 800 may include a selection component 808 or a precoding component 810, as well as one or more of the other examples.

[0124] In some respects, device 800 can be configured to perform the functions described herein. Figure 5 One or more operations described herein. Additionally or alternatively, apparatus 800 may be configured to perform one or more processes described herein, such as Figure 6 The process is 600. In some respects, Figure 8 The device 800 and / or one or more components shown may include the above-described combination. Figure 2 One or more components of the described base station. Additionally or alternatively, Figure 8 One or more components shown can be combined above. Figure 2 Implemented in one or more of the described components. Additionally or alternatively, one or more components in the set of components may be implemented at least partially as software stored in memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and may be executed by a controller or processor to perform the function or operation of the component.

[0125] Receiver 802 may receive communications from device 806, such as reference signals, control information, data communications, or combinations thereof. Receiver 802 may provide the received communications to one or more other components of device 800. In some aspects, receiver 802 may perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, demapping, equalization, interference cancellation, or decoding), and may provide the processed signals to one or more other components of device 806. In some aspects, receiver 802 may include the elements described above. Figure 2 The described base station includes one or more antennas, demodulators, MIMO detectors, receiver processors, controllers / processors, memory, or combinations thereof.

[0126] Transmitting component 804 can transmit communications, such as reference signals, control information, data communications, or combinations thereof, to device 806. In some aspects, one or more other components of device 806 can generate communications and provide the generated communications to transmitting component 804 for transmission to device 806. In some aspects, transmitting component 804 can perform signal processing (e.g., filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding) on ​​the generated communications and can transmit the processed signals to device 806. In some aspects, transmitting component 804 can include the combinations described above. Figure 2 The described base station includes one or more antennas, a modulator, a transmit MIMO processor, a transmit processor, a controller / processor, a memory, or a combination thereof. In some aspects, the transmit component 804 may coexist with the receive component 802 in a transceiver.

[0127] Selecting component 808 allows you to choose the precoding matrix for the orthogonal beams. In some aspects, selecting component 808 may include the combination of the above. Figure 2 The described base station includes one or more antennas, demodulators, MIMO detectors, receive processors, modulators, transmit MIMO processors, transmit processors, controllers / processors, memory, or combinations thereof. Precoding component 810 can precode the CSI-RS transmitted to the UE using a precoding matrix of orthogonal beams. In some aspects, precoding component 810 may include the above-described combination... Figure 2 The described base station includes one or more antennas, demodulators, MIMO detectors, receive processors, modulators, transmit MIMO processors, transmit processors, controllers / processors, memory, or combinations thereof. The receive component 802 can receive one or more reports from the UE indicating one or more beam indices selected from beam indices associated with the precoding matrix of orthogonal beams.

[0128] Selection component 808 can partition a matrix having dimensions at least partially based on O1, O2, N1, and N2 to form a precoding matrix for orthogonal beams, where O1 and O2 indicate DFT oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions. Selection component 808 can randomly select the precoding matrix for orthogonal beams from the matrix having dimensions at least partially based on O1, O2, N1, and N2. Selection component 808 can also select the precoding matrix for orthogonal beams based at least partially on a detection reference signal received from the UE.

[0129] Selection component 808 may select the precoding matrix of orthogonal beams based at least in part on the last beam index indicated in one or more last reports from the UE. Selection component 808 may select the precoding matrix of orthogonal beams based at least in part on the beam index most frequently selected among M last beam indices indicated in one or more last reports from the UE, where M is a positive integer.

[0130] Transmitting component 804 can send an indication of M to the UE via RRC signaling, MAC CE, or DCI. Transmitting component 804 can also send the beam index associated with the precoding matrix of the orthogonal beams used for precoding CSI-RS to the UE.

[0131] Figure 8 The number and arrangement of components shown are provided as an example. In reality, with... Figure 8 Compared to what is shown, there can be additional components, fewer components, different components, or components arranged differently. Furthermore, Figure 8 The two or more components shown can be implemented within a single component, or Figure 8 The single component shown can be implemented as multiple distributed components. Additionally or alternatively, Figure 8 The collection of (one or more) components shown can perform actions described as being performed by Figure 8 Another set of components shown performs one or more functions.

[0132] Figure 9 This is a block diagram of an example device 900 for wireless communication. Device 900 may be a UE, or a UE may include device 900. In some aspects, device 900 includes a receiving component 902 and a transmitting component 904, which can communicate with each other (e.g., via one or more buses and / or one or more other components). As shown, device 900 can use the receiving component 902 and the transmitting component 904 to communicate with another device 906 (such as a UE, a base station, or another wireless communication device). As further shown, among other examples, device 900 may include a selection component 908.

[0133] In some respects, device 900 can be configured to perform the functions described herein. Figure 5 One or more operations described herein. Additionally or alternatively, apparatus 900 may be configured to perform one or more processes described herein, such as Figure 7 The process is 700. In some respects, Figure 9 The device 900 and / or one or more components shown may include the above-described combination. Figure 2 One or more components of the UE described. Additionally or alternatively, Figure 9 One or more components shown can be combined above. Figure 2 Implemented in one or more of the described components. Additionally or alternatively, one or more components in the set of components may be implemented at least partially as software stored in memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and may be executed by a controller or processor to perform the function or operation of the component.

[0134] Receiver 902 may receive communications from device 906, such as reference signals, control information, data communications, or combinations thereof. Receiver 902 may provide the received communications to one or more other components of device 900. In some aspects, receiver 902 may perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, demapping, equalization, interference cancellation, or decoding), and may provide the processed signals to one or more other components of device 906. In some aspects, receiver 902 may include the combinations described above. Figure 2 The described UE includes one or more antennas, demodulators, MIMO detectors, receiver processors, controllers / processors, memory, or combinations thereof.

[0135] Transmitting component 904 can transmit communications, such as reference signals, control information, data communications, or combinations thereof, to device 906. In some aspects, one or more other components of device 906 can generate communications and provide the generated communications to transmitting component 904 for transmission to device 906. In some aspects, transmitting component 904 can perform signal processing (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding) on ​​the generated communications and can transmit the processed signals to device 906. In some aspects, transmitting component 904 can include the combinations described above. Figure 2 The described UE includes one or more antennas, modulators, transmit MIMO processors, transmit processors, controllers / processors, memory, or combinations thereof. In some aspects, the transmit component 904 may co-located with the receive component 902 in a transceiver.

[0136] The receiving component 902 can receive CSI-RS precoded using an orthogonal beaming precoding matrix from the base station. The selection component 908 can select one or more beam indices from the beam indices associated with the orthogonal beaming precoding matrix. In some aspects, the selection component 908 may include the combination of the above. Figure 2 The described UE includes one or more antennas, demodulators, MIMO detectors, receive processors, modulators, transmit MIMO processors, transmit processors, controllers / processors, memory, or combinations thereof. Transmit component 904 can transmit one or more reports to the base station indicating one or more beam indices.

[0137] The transmitting component 904 can transmit SRS to the base station, wherein the precoding matrix of the orthogonal beam is selected based at least in part on the SRS.

[0138] The receiving component 902 can receive the indication of M from the base station via RRC signaling, MAC CE or DCI.

[0139] Select component 908 can select one or more updated beam indices, which are updates to one or more beam indices indicated in the first report, wherein one or more reports include a second report indicating one or more updated beam indices.

[0140] The receiving component 902 can receive beam indices associated with the precoding matrix of orthogonal beams used for precoding CSI-RS from the base station.

[0141] Figure 9 The number and arrangement of components shown are provided as an example. In reality, with... Figure 9 Compared to what is shown, there can be additional components, fewer components, different components, or components arranged differently. Furthermore, Figure 9 The two or more components shown can be implemented within a single component, or Figure 9 The single component shown can be implemented as multiple distributed components. Additionally or alternatively, Figure 9 The set (one or more) components shown can perform actions described by Figure 9 The other set of components shown performs one or more functions.

[0142] The following provides an overview of some aspects of this disclosure:

[0143] Aspect 1: A method for wireless communication performed by a base station, comprising: selecting a precoding matrix of orthogonal beams; precoding a channel state information reference signal (CSI-RS) transmitted to a user equipment (UE) using the precoding matrix of orthogonal beams; and receiving from the UE one or more reports indicating one or more beam indices selected from beam indices associated with the precoding matrix of orthogonal beams.

[0144] Aspect 2: According to the method of aspect 1, wherein selecting the precoding matrix of the orthogonal beam comprises: dividing a matrix having dimensions at least partially based on O1, O2, N1 and N2 to form the precoding matrix of the orthogonal beam, wherein O1 and O2 indicate discrete Fourier transform (DFT) oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions.

[0145] Aspect 3: According to the method of aspect 2, wherein selecting the precoding matrix of the orthogonal beams comprises: randomly selecting the precoding matrix of the orthogonal beams from a matrix having at least partially ground-based dimensions O1, O2, N1 and N2.

[0146] Aspect 4: The method according to any one of aspects 1 to 3, wherein selecting the precoding matrix of the orthogonal beams includes: selecting the precoding matrix of the orthogonal beams based at least in part on the detection reference signal received from the UE.

[0147] Aspect 5: The method according to any one of aspects 1 to 4, wherein selecting the precoding matrix of the orthogonal beams includes: selecting the precoding matrix of the orthogonal beams based at least in part on the last beam index indicated in one or more last reports from the UE.

[0148] Aspect 6: The method according to any one of aspects 1 to 5, wherein selecting the precoding matrix of the orthogonal beam comprises: selecting the precoding matrix of the orthogonal beam based at least in part on the beam index most frequently selected among M last beam indices indicated from one or more last reports from the UE, where M is a positive integer.

[0149] Aspect 7: The method according to aspect 6 further includes: sending an indication of M to the UE via radio resource control (RRC) signaling, media access control (MAC) control element (CE) or downlink control information (DCI).

[0150] Aspect 8: The method according to any one of aspects 1 to 7, wherein one or more reports include a first report indicating one or more beam indices selected by the UE.

[0151] Aspect 9: The method according to any one of aspects 1 to 8, wherein one or more reports include a second report indicating one or more updated beam indices selected by the UE.

[0152] Aspect 10: The method according to any one of aspects 1 to 9 further includes: sending to the UE a beam index associated with a precoding matrix for precoding orthogonal beams of CSI-RS.

[0153] Aspect 11: A method of wireless communication performed by a user equipment (UE), comprising: receiving from a base station a channel state information reference signal (CSI-RS) precoded using a precoding matrix of orthogonal beams; selecting one or more beam indices from beam indices associated with the precoding matrix of orthogonal beams; and sending to the base station one or more reports indicating the one or more beam indices.

[0154] Aspect 12: According to the method of aspect 11, the precoding matrix of the orthogonal beam is a submatrix of a matrix having dimensions at least partially based on O1, O2, N1 and N2, where O1 and O2 indicate Discrete Fourier Transform (DFT) oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions.

[0155] Aspect 13: According to the method of aspect 12, the precoding matrix of the orthogonal beam is randomly selected from a matrix having dimensions at least partially based on O1, O2, N1 and N2.

[0156] Aspect 14: The method according to any one of aspects 11 to 13 further includes: transmitting a sounding reference signal to a base station, wherein the precoding matrix of the orthogonal beam is selected based at least in part on the sounding reference signal.

[0157] Aspect 15: The method according to any one of aspects 11 to 14, wherein the precoding matrix of the orthogonal beam is selected based at least in part on the last beam index indicated in one or more last reports from the UE.

[0158] Aspect 16: The method according to any one of aspects 11 to 15, wherein the precoding matrix of the orthogonal beam is selected based at least in part on the beam index most frequently selected among M last beam indices indicated from one or more last reports from the UE, where M is a positive integer.

[0159] Aspect 17: The method according to aspect 16 further includes receiving an indication of M from the base station via radio resource control (RRC) signaling, media access control (MAC) control element (CE) or downlink control information (DCI).

[0160] Aspect 18: The method according to any one of aspects 11 to 17, wherein one or more reports include a first report indicating one or more beam indices.

[0161] Aspect 19: The method according to aspect 18 further includes: selecting one or more updated beam indices, which are updates to one or more beam indices indicated in the first report, wherein the one or more reports include a second report indicating one or more updated beam indices.

[0162] Aspect 20: The method according to any one of aspects 11 to 19 further includes: receiving from the base station a beam index associated with a precoding matrix for precoding orthogonal beams of CSI-RS.

[0163] Aspect 21: An apparatus for wireless communication at a device, comprising a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform one or more of the methods of aspects 1-10.

[0164] Aspect 22: An apparatus for wireless communication, comprising a memory and one or more processors coupled to the memory, the one or more processors being configured to perform the methods of one or more aspects of aspects 1-10.

[0165] Aspect 23: An apparatus for wireless communication, comprising at least one component for performing the methods of one or more aspects of aspects 1-10.

[0166] Aspect 24: A non-transitory computer-readable medium storing code for wireless communication, the code including instructions executable by a processor to perform methods of one or more aspects of aspects 1-10.

[0167] Aspect 25: A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising one or more instructions, which, when executed by one or more processors of a device, cause the device to perform the methods of one or more aspects of aspects 1-10.

[0168] Aspect 26: An apparatus for wireless communication at a device, comprising a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform one or more of the methods of aspects 11-20.

[0169] Aspect 27: An apparatus for wireless communication, comprising a memory and one or more processors coupled to the memory, the one or more processors being configured to perform the methods of one or more aspects of aspects 11-20.

[0170] Aspect 28: An apparatus for wireless communication, comprising at least one component for performing the methods of one or more aspects of aspects 11-20.

[0171] Aspect 29: A non-transitory computer-readable medium storing code for wireless communication, the code including instructions executable by a processor to perform methods of one or more aspects of aspects 11-20.

[0172] Aspect 30: A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising one or more instructions, which, when executed by one or more processors of a device, cause the device to perform the methods of one or more aspects of aspects 11-20.

[0173] The foregoing disclosure provides illustrations and descriptions, but is not intended to be exhaustive or to limit these aspects to the precise forms disclosed. Modifications and variations can be made based on the foregoing disclosure, or from practice in these aspects.

[0174] As used herein, the term "component" is intended to be interpreted broadly as hardware and / or a combination of hardware and software. "Software" should be interpreted broadly as instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable programs, threads of execution, procedures and / or functions, and other examples, whether referred to as software, firmware, middleware, microcode, hardware description languages, or others. As used herein, a "processor" is implemented in hardware and / or a combination of hardware and software. It is obvious that the systems and / or methods described herein can be implemented in various forms of hardware and / or combinations of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods is not limiting to these aspects. Therefore, no specific software code is referenced in the description of the operation and behavior of the systems and / or methods herein, as those skilled in the art will understand that software and hardware can be designed to implement the systems and / or methods, at least in part, based on the description herein.

[0175] As used here, “meeting the threshold” can refer to a value greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, etc., depending on the context.

[0176] Even if a particular combination of features is stated in the claims and / or disclosed in the specification, such combinations are not intended to limit the disclosure of aspects. Many of these features may be combined in ways not specifically stated in the claims and / or not disclosed in the specification. Disclosure of aspects includes combinations of each dependent claim with each other claim in the group of claims. As used herein, the phrase “at least one” in the list of denotations refers to any combination of those items, including single members. For example, “at least one of a, b, or c” is intended to cover a, b, c, a+b, a+c, b+c, and a+b+c, as well as any combination having multiple identical elements (e.g., a+a, a+a+a, a+a+b, a+a+c, a+b+b, a+c+c, b+b, b+b+b, b+b+c, c+c, and c+c+c, or any other order of a, b, and c).

[0177] Unless explicitly stated otherwise, no element, action, or instruction used herein should be construed as critical or necessary. Furthermore, as used herein, the articles “a” and “one” are intended to include one or more items and may be used interchangeably with “one or more.” Furthermore, as used herein, the article “the” is intended to include one or more items mentioned in connection with the article “the” and may be used interchangeably with “the one or more.” Furthermore, as used herein, the terms “set” and “group” are intended to include one or more items and may be used interchangeably with “one or more.” If referring to only one item, the phrase “only one” or similar language is used. Furthermore, as used herein, the terms “have,” “possess,” “contain,” etc., are intended to be open-ended terms, not limiting the elements they modify (e.g., an element “having” A may also have B). Furthermore, the phrase “based on” is intended to mean “at least partially based on”, unless explicitly stated otherwise. Furthermore, as used herein, the term “or” is intended to be inclusive in a series of uses and may be used interchangeably with “and / or”, unless explicitly stated otherwise (e.g., if used in conjunction with “any” or “only one”).

Claims

1. A method for wireless communication performed by a base station, the method comprising: A matrix with dimensions at least partially based on O1, O2, N1, and N2 is used to form a precoding matrix for orthogonal beams, where O1 and O2 indicate Discrete Fourier Transform (DFT) oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions. The channel state information reference signal (CSI-RS) transmitted to the user equipment (UE) is precoded using an orthogonal beam precoding matrix; and The UE receives one or more reports indicating the selection of one or more beam indices from the beam indices associated with the precoding matrix of orthogonal beams.

2. The method according to claim 1, further comprising: A precoding matrix for randomly selecting orthogonal beams from a matrix having dimensions at least partially based on O1, O2, N1, and N2.

3. The method according to claim 1, further comprising: The precoding matrix of the orthogonal beam is selected based at least in part on the probe reference signal received from the UE.

4. The method according to claim 1, further comprising: The precoding matrix of orthogonal beams is selected based at least in part on the last beam index indicated in one or more last reports from the UE.

5. The method of claim 1, further comprising: The precoding matrix for orthogonal beams is selected at least in part based on the most frequently selected beam index among M last beam indices indicated from one or more last reports from the UE, where M is a positive integer, and further includes: Instructions for M are sent to the UE via Radio Resource Control (RRC) signaling, Media Access Control (MAC) control element (CE), or Downlink Control Information (DCI).

6. The method of claim 1, wherein one or more reports include a first report indicating one or more beam indices selected by the UE.

7. The method of claim 1, wherein one or more reports include a second report indicating one or more updated beam indices selected by the UE.

8. The method of claim 1, further comprising: Send the beam index associated with the precoding matrix of the orthogonal beams used for precoding CSI-RS to the UE.

9. A method for wireless communication performed by a user equipment (UE), the method comprising: Receive channel state information reference signal (CSI-RS) precoded using a precoding matrix with orthogonal beams from the base station. The precoding matrix of the orthogonal beam is a submatrix of a matrix having dimensions at least partially based on O1, O2, N1, and N2, where O1 and O2 indicate Discrete Fourier Transform (DFT) oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions. Select one or more beam indices from the beam indices associated with the precoding matrix of the orthogonal beams; and Send one or more reports to the base station indicating one or more beam indices.

10. The method of claim 9, wherein the precoding matrix of the orthogonal beam is randomly selected from a matrix having dimensions at least partially based on O1, O2, N1, and N2.

11. The method of claim 9, further comprising: A sounding reference signal is sent to the base station, wherein the precoding matrix of the orthogonal beam is selected based at least in part on the sounding reference signal.

12. The method of claim 9, wherein the precoding matrix of the orthogonal beams is selected based at least in part on the last beam index indicated in one or more last reports from the UE.

13. The method of claim 9, wherein the precoding matrix of the orthogonal beam is selected based at least in part on the beam index most frequently selected among M last beam indices indicated from one or more last reports from the UE, wherein M is a positive integer, and the method further comprises: The instruction of M is received from the base station via Radio Resource Control (RRC) signaling, Media Access Control (MAC) control element (CE), or Downlink Control Information (DCI).

14. The method of claim 9, wherein one or more reports include a first report indicating the one or more beam indices, and further includes selecting one or more updated beam indices as an update to the one or more beam indices indicated in the first report, wherein the one or more reports include a second report indicating the one or more updated beam indices.

15. The method of claim 9, further comprising: Receive beam indices from the base station that are associated with the precoding matrix of the orthogonal beams used for precoding CSI-RS.

16. A base station for wireless communication, comprising: Memory; and One or more processors coupled to the memory are configured to cause the base station to: The precoding matrix of orthogonal beams is selected based at least in part on the most frequently selected beam index among the M last beam indices indicated in one or more last reports from the user equipment (UE), where M is a positive integer; The channel state information reference signal (CSI-RS) sent to the UE is precoded using an orthogonal beam precoding matrix; and The UE receives one or more reports indicating the selection of one or more beam indices from the beam indices associated with the precoding matrix of orthogonal beams.

17. The base station of claim 16, wherein when selecting a precoding matrix for orthogonal beams, the one or more processors are configured to cause the base station to: A matrix with dimensions at least partially based on O1, O2, N1, and N2 is used to form a precoding matrix for orthogonal beams, where O1 and O2 indicate Discrete Fourier Transform (DFT) oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions.

18. The base station of claim 17, wherein when selecting the precoding matrix of orthogonal beams, the one or more processors are configured to cause the base station to: A precoding matrix for randomly selecting orthogonal beams from a matrix having dimensions at least partially based on O1, O2, N1, and N2.

19. The base station of claim 16, wherein when selecting a precoding matrix for orthogonal beams, the one or more processors are configured to cause the base station to: The precoding matrix of the orthogonal beam is selected based at least in part on the probe reference signal received from the UE.

20. The base station of claim 16, wherein one or more processors are further configured to cause the base station to send an indication of M to the UE via Radio Resource Control (RRC) signaling, Media Access Control (MAC) control element (CE) or Downlink Control Information (DCI).

21. The base station of claim 16, wherein one or more reports include a first report indicating one or more beam indices selected by the UE.

22. The base station of claim 16, wherein one or more reports include a second report indicating one or more updated beam indices selected by the UE.

23. The base station of claim 16, wherein one or more processors are further configured to cause the base station to: Send the beam index associated with the precoding matrix of the orthogonal beams used for precoding CSI-RS to the UE.

24. A user equipment (UE) for wireless communication, comprising: Memory; and One or more processors coupled to the memory, the one or more processors being configured to cause the UE to: Receive channel state information reference signal (CSI-RS) precoded using a precoding matrix with orthogonal beams from the base station. The precoding matrix of the orthogonal beam is selected at least in part based on the most frequently selected beam index among M last beam indices indicated in one or more last reports from the UE, where M is a positive integer; Select one or more beam indices from the beam indices associated with the precoding matrix of the orthogonal beams; and Send one or more reports to the base station indicating one or more beam indices.

25. The UE of claim 24, wherein the precoding matrix of the orthogonal beam is a submatrix of a matrix having dimensions at least partially based on O1, O2, N1, and N2, wherein O1 and O2 indicate Discrete Fourier Transform (DFT) oversampled values, and N1 and N2 are at least partially based on the number of antennas in the horizontal and vertical dimensions.

26. The UE of claim 25, wherein the precoding matrix of the orthogonal beam is randomly selected from a matrix having dimensions at least partially based on O1, O2, N1, and N2.

27. The UE of claim 24, wherein one or more processors are further configured to cause the UE to: A sounding reference signal is sent to the base station, wherein the precoding matrix of the orthogonal beam is selected based at least in part on the sounding reference signal.

28. The UE of claim 24, wherein the one or more processors are further configured to cause the UE to receive an indication of M from the base station via Radio Resource Control (RRC) signaling, Media Access Control (MAC) control element (CE) or Downlink Control Information (DCI).

29. The UE of claim 24, wherein one or more reports include a first report indicating the one or more beam indices, and wherein the one or more processors are further configured to cause the UE to select one or more updated beam indices as an update to the one or more beam indices indicated in the first report, wherein the one or more reports include a second report indicating the one or more updated beam indices.

30. The UE of claim 24, wherein the one or more processors are further configured to cause the UE to: Receive beam indices from the base station that are associated with the precoding matrix of the orthogonal beams used for precoding CSI-RS.

31. A base station comprising components for performing the steps of the method according to any one of claims 1 to 8.

32. A user equipment (UE) comprising a component for performing the steps of the method according to any one of claims 9 to 15.

33. A non-transitory readable storage medium comprising instructions that, when executed by a processor of a base station, cause the base station to perform the method according to any one of claims 1 to 8.

34. A non-transitory readable storage medium comprising instructions that, when executed by a processor of a user equipment (UE), cause the UE to perform the method according to any one of claims 9 to 15.

35. A program product comprising instructions that, when executed by a processor of a base station, cause the base station to perform the method according to any one of claims 1 to 8.

36. A program product comprising instructions that, when executed by a processor of a user equipment (UE), cause the UE to perform the method according to any one of claims 9 to 15.

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