Beam switching based at least in part on negative acknowledgement transmissions

Abstract

Various aspects of the disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) can transmit a measurement report indicating a set of channel quality indicators for a set of candidate beams, determine that a downlink transmission from a base station is not received via one or more beams of the set of candidate beams, and transmit a negative acknowledgement for the downlink transmission via one or more new beams of the set of candidate beams. Numerous other aspects are provided.

Description

[0001] Cross-references to related applications

[0002] This patent application claims priority to Greek patent application No. 20200100110, filed on February 28, 2020, entitled “BEAM SWITCHING BASED AT LEASTIN PART ON A NEGATIVE ACKNOWLEDGEMENT TRANSMISSION”, assigned to the assignee of this application. The disclosure of that earlier application is considered part of this patent application and is incorporated herein by reference.

[0003] open field

[0004] Various aspects of this disclosure generally relate to wireless communication, and to techniques and apparatus for beam switching based at least in part on negatively acknowledged (NACK) transmissions.

[0005] background

[0006] 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 can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). 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 an enhancement set of the Universal Mobile Telecommunications System (UMTS) mobile standard issued by the 3rd Generation Partnership Project (3GPP).

[0007] A wireless network may include several base stations (BSs) capable of supporting communication between several user equipments (UEs). UEs can communicate with the BS via downlink and uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, while the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in more detail herein, the BS may be referred to as a B-node, gNB, access point (AP), radio headend, transmit / receive point (TRP), new radio (NR) BS, 5G B-node, etc.

[0008] The above multiple access technologies have been adopted in various telecommunications standards to provide a common protocol enabling different user equipment to communicate at the city, country, region, and even global levels. NR (which can also be referred to as 5G) is an enhancement set of the LTE mobile standard issued by 3GPP. NR is designed to better support mobile broadband Internet access by using Orthogonal Frequency Division Multiplexing (OFDM) with a Cyclic Prefix (CP) (CP-OFDM) on the downlink (DL), and using CP-OFDM and / or SC-FDM (e.g., also known as Discrete Fourier Transform Extended OFDM (DFT-s-OFDM)) on the uplink (UL), as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technologies and carrier aggregation to improve spectral efficiency, reduce costs, improve service, utilize new spectrum, and better integrate with other open standards. Further improvements to LTE, NR, and other radio access technologies remain useful as the demand for mobile broadband access continues to grow.

[0009] Overview

[0010] In some aspects, a wireless communication method performed by a user equipment (UE) may include: transmitting a measurement report indicating a set of channel quality indicators (CQIs) for a set of candidate beams; determining that no downlink transmission from a base station has been received via one or more beams in the set of candidate beams; and transmitting a negative acknowledgment (NACK) for the downlink transmission via one or more new beams in the set of candidate beams.

[0011] In some aspects, a wireless communication method performed by a base station may include: receiving from a UE a measurement report indicating a set of CQI for a candidate beam set; transmitting a downlink transmission to the UE via one or more beams in the candidate beam set; and receiving a NACK from the UE for the downlink transmission via one or more new beams in the candidate beam set.

[0012] In some aspects, a UE for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: transmit a measurement report indicating a set of CQI values ​​for a set of candidate beams; determine that no downlink transmission from a base station has been received via one or more beams in the set of candidate beams; and transmit a NACK for the downlink transmission via one or more new beams in the set of candidate beams.

[0013] In some aspects, a base station for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: receive from a UE a measurement report indicating a set of CQI for a candidate beam set; transmit downlink transmissions to the UE via one or more beams in the candidate beam set; and receive NACKs from the UE for the downlink transmissions via one or more new beams in the candidate beam set.

[0014] In some aspects, a non-transient computer-readable medium may store one or more instructions for wireless communication. When executed by one or more processors of the UE, the one or more instructions may cause the processors to perform the following operations: transmit a measurement report indicating a set of CQI values ​​for a candidate beam set; determine that no downlink transmission from a base station has been received via one or more beams in the candidate beam set; and transmit a NACK for the downlink transmission via one or more new beams in the candidate beam set.

[0015] In some aspects, a non-transient computer-readable medium may store one or more instructions for wireless communication. When executed by one or more processors of a base station, the one or more instructions may cause the processors to perform the following operations: receive from a UE a measurement report indicating a set of CQI for a candidate beam set; transmit a downlink transmission to the UE via one or more beams in the candidate beam set; and receive a NACK from the UE for the downlink transmission via one or more new beams in the candidate beam set.

[0016] In some aspects, an apparatus for wireless communication may include: means for transmitting a measurement report indicating a set of CQI for a set of candidate beams; means for determining that no downlink transmission from a base station has been received via one or more beams in the set of candidate beams; and means for transmitting a NACK for the downlink transmission via one or more new beams in the set of candidate beams.

[0017] In some aspects, an apparatus for wireless communication may include: means for receiving from a UE a measurement report indicating a set of CQI for a candidate beam set; means for transmitting a downlink transmission to the UE via one or more beams in the candidate beam set; and means for receiving a NACK from the UE for the downlink transmission via one or more new beams in the candidate beam set.

[0018] The aspects generally include, as substantially described herein with reference to the accompanying drawings and description, methods, apparatus, systems, computer program products, non-transient computer-readable media, user equipment, base stations, wireless communication equipment, and / or processing systems.

[0019] The foregoing has broadly outlined the features and technical advantages of the examples according to this disclosure in an effort to facilitate a better understanding of the following detailed description. Additional features and advantages will be described thereafter. The disclosed concepts and specific examples can be readily used as the basis for modifications or the design of other structures for implementing the same purposes as this disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, in both their organization and manner of operation, and their associated advantages, will be better understood by considering the following description in conjunction with the accompanying drawings. Each drawing is provided for illustrative and descriptive purposes and not for defining limitations on the claims.

[0020] While aspects are described herein by way of example, 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 may 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 / shopping devices, medical devices, or AI-enabled devices). Aspects can be implemented in chip-level components, modular components, non-modular components, non-chip-level components, device-level components, 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 several components (e.g., hardware components, including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders, or summers) for analog and digital purposes. The aspects described herein are intended to be practiced in a wide variety of devices, components, systems, distributed arrangements, or end-user equipment of various sizes, shapes, and configurations. Brief description of the attached diagram

[0022] To gain a more detailed understanding of the features described above in this disclosure, reference can be made to various aspects of the above brief overview, 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 other equivalent aspects are permissible in this description. Identical reference numerals in different drawings may identify the same or similar elements.

[0023] Figure 1 This is a diagram illustrating an example of a wireless network according to this disclosure.

[0024] Figure 2 This is a diagram illustrating an example of communication between a base station and a user equipment (UE) in a wireless network according to this disclosure.

[0025] Figure 3 This is a diagram illustrating an example of Hybrid Automatic Repeat Request (HARQ) feedback according to this disclosure.

[0026] Figure 4 This is a diagram illustrating an example of HARQ feedback based on this disclosure.

[0027] Figure 5 This is a diagram illustrating an example of beam switching based at least in part on negative acknowledgment (NACK) transmissions according to this disclosure.

[0028] Figure 6 This is a diagram illustrating an example of beam switching based at least in part on NACK transmission according to this disclosure.

[0029] Figure 7 This is a diagram illustrating an example of beam switching based at least in part on NACK transmission according to this disclosure.

[0030] Figure 8 This is a diagram illustrating an example procedure performed by a UE according to this disclosure.

[0031] Figure 9 This is a diagram illustrating an example process performed by a base station according to this disclosure.

[0032] Detailed description

[0033] The various aspects of this disclosure are 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 being limited to any specific structure or function given throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. Based on the teachings herein, those skilled in the art will appreciate that the scope of this disclosure is intended to cover any aspect of this disclosure disclosed herein, whether implemented independently of or in combination with any other aspect of this disclosure. For example, any number of aspects set forth herein may be used to implement an apparatus or method of practice. Furthermore, the scope of this disclosure is intended to cover such apparatus or methods practiced using additional structures, functionalities, or structures and functionalities that complement or supplement the various aspects of this disclosure set forth herein. It should be understood that any aspect of this disclosure disclosed herein may be implemented by one or more elements of the claims.

[0034] 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 the following detailed description and explained 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 such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0035] It should be noted that although the aspects are described herein using terms commonly associated with 5G or NR radio access technology (RAT), 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).

[0036] Figure 1 This is a diagram illustrating an example of a wireless network 100 according to this disclosure. The wireless network 100 may be a 5G (NR) network and / or an LTE network, etc., or may include elements thereof. The wireless network 100 may include several base stations 110 (shown as BS110a, BS 110b, BS 110c, and BS 110d) and other network entities. A base station (BS) is an entity that communicates with a user equipment (UE) and may also be referred to as an NR BS, B-node, gNB, 5G B-node (NB), access point, transmit / receive point (TRP), etc. Each BS may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to the coverage area of ​​a BS and / or the BS subsystem serving that coverage area, depending on the context in which the term is used.

[0037] A BS can provide communication coverage for macrocells, picocells, femtocells, and / or another type of cell. Macrocells can cover a relatively large geographic area (e.g., a radius of several kilometers) and allow unrestricted access by UEs with a service subscription. Picocells can cover a relatively small geographic area and allow unrestricted access by UEs with a service subscription. Femtocells can cover a relatively small geographic area (e.g., a residential area) and allow restricted access by UEs associated with that femtocell (e.g., UEs in a Closed Subscriber Group (CSG)). A BS used for macrocells may be referred to as a macro BS. A BS used for picocells may be referred to as a pico BS. A BS used for femtocells may be referred to as a femto BS or a home BS. Figure 1In the example shown, BS 110a can be a macro BS for macro cell 102a, BS 110b can be a pico BS for pico cell 102b, and BS 110c can be a femto BS for femto cell 102c. A BS can support one or more (e.g., three) cells. The terms “eNB,” “base station,” “NR BS,” “gNB,” “TRP,” “AP,” “B node,” “5G NB,” and “cell” are used interchangeably herein.

[0038] In some respects, the cell may not be stationary, and the geographical area of ​​the cell may move depending on the location of the mobile BS. In some respects, BSs may interconnect with each other and / or interconnect to one or more other BSs or network nodes (not shown) in the wireless network 100 via various types of backhaul interfaces (such as direct physical connections or virtual networks, using any suitable transport network).

[0039] The wireless network 100 may also include a relay station. A relay station is an entity capable of receiving data transmissions from an upstream station (e.g., a BS or a UE) and transmitting those data transmissions to a downstream station (e.g., a UE or a BS). A relay station can also be a UE capable of relaying transmissions for other UEs. Figure 1 In the example shown, relay BS 110d can communicate with macro BS 110a and UE 120d to facilitate communication between BS 110a and UE 120d. A relay BS can also be referred to as a relay station, relay base station, relay, etc.

[0040] Wireless network 100 can be a heterogeneous network comprising different types of Base Stations (BSs) such as macro BSs, pico BSs, femto BSs, relay BSs, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in wireless network 100. For example, macro BSs may have high transmit power levels (e.g., 5 to 40 watts), while pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0.1 to 2 watts).

[0041] Network controller 130 can be coupled to a set of Base Stations (BSs) and can provide coordination and control over these BSs. Network controller 130 can communicate with each BS via backhaul. These BSs can also communicate with each other directly or indirectly via wireless or wired backhaul.

[0042] UE 120 (e.g., 120a, 120b, 120c) may be distributed throughout the wireless network 100, and each UE may be stationary or mobile. UE may also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. UE may be a cellular phone (e.g., a smartphone), personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet, camera, gaming device, netbook, smartbook, ultrabook, medical device or equipment, biometric sensor / device, wearable device (smartwatch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet)), entertainment device (e.g., music or video device, or satellite radio), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, GPS device, or any other suitable device configured to communicate via wireless or wired media.

[0043] Some UEs may be considered Machine-Type Communication (MTC) UEs, or evolved or enhanced Machine-Type Communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, instruments, monitors, and / or location tags that can communicate with a base station, another device (e.g., a remote device), or some other entity. Wireless nodes may provide connectivity to or to a network (e.g., a wide area network, such as the Internet) or a cellular network, for example, via wired or wireless communication links. Some UEs may be considered Internet of Things (IoT) devices, and / or may be implemented as NB-IoT (Narrowband Internet of Things) devices. Some UEs may be considered Customer Premises Equipment (CPE). UE120 may be included within a housing that houses components of UE120, such as processor components and / or memory components. In some aspects, 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.

[0044] Generally, any number of wireless networks can be deployed in a given geographical area. Each wireless network can support a specific RAT and can operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, frequency 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.

[0045] In some respects, 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 an intermediary). 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 or vehicle-to-infrastructure (V2I) protocols), and / or mesh networks. In this scenario, UE 120 may perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein as being performed by base station 110.

[0046] Devices in the wireless network 100 can communicate using the electromagnetic spectrum, which can be subdivided into various categories, bands, channels, etc., based on frequency or wavelength. For example, devices in the wireless network 100 can communicate using an operating band with a first frequency range (FR1) and / or an operating band with a second frequency range (FR2), where the first frequency range (FR1) spans from 410 MHz to 7.125 GHz and the second frequency range (FR2) spans from 24.25 GHz to 52.6 GHz. The frequencies between FR1 and FR2 are sometimes referred to as intermediate frequency (IF) bands. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to as the "sub-6 GHz" band. Similarly, although distinct from the Extremely High Frequency (EHF) band (30 GHz–300 GHz) designated as the "millimeter wave" band by the International Telecommunication Union (ITU), FR2 is often referred to as the "millimeter wave" band. Therefore, unless otherwise stated, it should be understood that, if used herein, the terms "sub-6 GHz" and the like can broadly refer to frequencies less than 6 GHz, frequencies within FR1, and / or intermediate frequency band frequencies (e.g., greater than 7.125 GHz). Similarly, unless otherwise stated, it should be understood that, if used herein, the terms "millimeter wave" and the like can broadly refer to frequencies within the EHF band, frequencies within FR2, and / or intermediate frequency band frequencies (e.g., less than 24.25 GHz). It is conceivable that the frequencies included in FR1 and FR2 can be modified, and the techniques described herein are applicable to those modified frequency ranges.

[0047] As indicated above, Figure 1 This is provided as an example. Other examples may differ from the one provided. Figure 1 The example described.

[0048] Figure 2This is a diagram illustrating an example 200 of communication between a base station 110 and a UE 120 in a wireless network 100 according to this disclosure. The base station 110 may be equipped with T antennas 234a to 234t, and the UE 120 may be equipped with R antennas 252a to 252r, wherein generally T≥1 and R≥1.

[0049] At base station 110, transmit processor 220 can receive data destined for one or more UEs from data source 212, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQI) received from each UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS selected for each UE, and provide data symbols for all UEs. Transmit processor 220 can also process system information (e.g., semi-static resource allocation information (SRPI)) and control information (e.g., CQI requests, grants, and / or upper-layer signaling), and provide overhead symbols and control symbols. Transmit processor 220 can also 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) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols, where applicable, and can provide T output symbol streams to T modulators (MODs) 232a to 232t. Each modulator 232 can process its respective output symbol stream (e.g., for OFDM) to obtain an output sample stream. Each modulator 232 can further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a to 232t can be transmitted via T antennas 234a to 234t, respectively.

[0050] At UE 120, antennas 252a to 252r can receive downlink signals from base station 110 and / or other base stations and can provide the received signals to demodulators (DEMODs) 254a to 254r respectively. Each demodulator 254 can condition (e.g., filter, amplify, downconvert, and digitize) the received signal to obtain an input sample. Each demodulator 254 can further process the input sample (e.g., for OFDM) to obtain received symbols. MIMO detector 256 can obtain the received symbols from all R demodulators 254a to 254r, perform MIMO detection on these received symbols where applicable, and provide detected symbols. Receiver processor 258 can process (e.g., demodulate and decode) these detected symbols, provide decoded data for UE 120 to data sink 260, and provide decoded control information and system information to 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 Reference Signal Received Power (RSRP), Received Signal Strength Indicator (RSSI), Reference Signal Received Quality (RSRQ), and / or CQI. In some respects, one or more components of the UE 120 may be included in the housing 284.

[0051] 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 the core network. Network controller 130 may communicate with base station 110 via communication unit 294.

[0052] Antennas (e.g., antennas 234a to 234t and / or antennas 252a to 252r) may include or be included within one or more antenna panels, antenna groups, antenna element assemblies, and / or antenna arrays. Antenna panels, antenna groups, antenna element assemblies, and / or antenna arrays may include one or more antenna elements. Antenna panels, antenna groups, antenna element assemblies, and / or antenna arrays may include coplanar antenna element assemblies and / or non-coplanar antenna element assemblies. Antenna panels, antenna groups, antenna element assemblies, and / or antenna arrays may include antenna elements within a single housing and / or multiple antenna elements within housings. Antenna panels, antenna groups, antenna element assemblies, and / or antenna arrays may include elements coupled to one or more transmission and / or reception components (such as...). Figure 2 One or more antenna elements (one or more components).

[0053] On the uplink, at UE 120, transmit processor 264 can receive and process data from data source 262 and control information from controller / processor 280 (e.g., reports including RSRP, RSSI, RSRQ, and / or CQI). Transmit processor 264 can also generate reference symbols for one or more reference signals. Symbols from transmit processor 264 may be pre-encoded by TX MIMO processor 266 where applicable, further processed by modulators 254a to 254r (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to base station 110. In some aspects, modulators and demodulators (e.g., MOD / DEMOD 254) of UE 120 may be included in the modem of UE 120. In some aspects, UE 120 includes a transceiver. The transceiver may include any combination of antennas 252, modulators and / or demodulators 254, MIMO detectors 256, receiver processors 258, transmitter processors 264, and / or TX MIMO processors 266. The transceiver may be used by a processor (e.g., controller / processor 280) and memory 282 to perform aspects of any of the methods described herein, for example, as referenced. Figure 5-9 As described.

[0054] At base station 110, uplink signals from UE 120 and other UEs can be received by antenna 234, processed by demodulator 232, detected by MIMO detector 236 where applicable, and further processed by receiver processor 238 to obtain decoded data and control information transmitted by UE 120. Receiver processor 238 can 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 communicate with network controller 130 via communication unit 244. Base station 110 may include scheduler 246 to schedule UE 120 for downlink and / or uplink communications. In some aspects, the modulator and demodulator (e.g., MOD / DEMOD 232) of base station 110 may be included in the modem of base station 110. In some aspects, base station 110 includes a transceiver. The transceiver may include any combination of antenna 234, modulator and / or demodulator 232, MIMO detector 236, receiver processor 238, transmitter processor 220, and / or TX MIMO processor 230. The transceiver may be used by a processor (e.g., controller / processor 240) and memory 242 to perform aspects of any of the methods described herein, for example, as referenced. Figure 5-9 As described.

[0055] The controller / processor 240 of base station 110, the controller / processor 280 of UE 120, and / or Figure 2 Any other component may perform one or more techniques associated with beam switching based at least in part on NACK transmissions, 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 may execute or direct, for example Figure 8 The process 800 Figure 9 The operation of process 900 and / or other processes as described herein. Memory 242 and 282 may store data and program code for base station 110 and UE 120, respectively. In some aspects, 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 executed by one or more processors of base station 110 and / or UE 120 (e.g., direct execution, or execution after compilation, transformation, and / or interpretation), the one or more processors, UE 120, and / or base station 110 may cause the one or more processors, UE 120, and / or base station 110 to perform or direct, for example... Figure 8 The process 800 Figure 9 The operation of process 900, and / or other processes described herein. In some aspects, the execution instructions may include run instructions, translate instructions, compile instructions, and / or interpret instructions, etc.

[0056] In some aspects, the UE includes: means for transmitting a measurement report indicating a set of channel quality indicators for a candidate beam set; means for determining that downlink transmissions from a base station have not been received via one or more beams in the candidate beam set; or means for transmitting a negative acceptance of downlink transmissions via one or more new beams in the candidate beam set. Means for the UE to perform the operations described herein may include, for example, one or more of antenna 252, demodulator 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, modulator 254, controller / processor 280, or memory 282.

[0057] In some aspects, the UE includes: means for performing beam sweeping using one or more new beams.

[0058] In some aspects, the UE includes: means for performing beam sweeping using the one or more new beams and the one or more new beams.

[0059] In some aspects, the UE includes: means for sequentially transmitting negative acknowledgments for downlink transmissions via the one or more new beams and the one or more beams in order at least in part based on a set of channel quality indicators.

[0060] In some aspects, the UE includes: means for transmitting a negative acceptance for a downlink transmission via one or more beams in the candidate beam set; or means for receiving an indication that the base station interprets a Hybrid Automatic Repeat Request (HARQ) feedback timing associated with the negative acceptance as acceptance, wherein transmitting the negative acceptance for the downlink transmission via the one or more new beams is at least in part based on a mismatch between the base station's interpretation and the negative acceptance.

[0061] In some aspects, the UE includes: means for receiving radio resource control (RRC) reconfiguration, RRC connection establishment, RRC reconstruction, RRC establishment, or RRC recovery signaling including monitoring the candidate beam set to search for one or more reference signals; means for configuring the UE to monitor the candidate beam set to search for the one or more reference signals; or means for transmitting an indication that the UE is configured to monitor the candidate beam set to search for the one or more reference signals.

[0062] In some aspects, the UE includes: means for obtaining measurements of the one or more reference signals received on the candidate beam set; or means for determining the ranking of candidate beams in the candidate beam set based at least in part on the measurements of the one or more reference signals.

[0063] In some aspects, the UE includes: means for selecting one or more beams for receiving downlink transmissions, at least in part based on a set of channel quality indicators.

[0064] In some aspects, the UE includes means for selecting the number of the one or more beams, at least in part, based on the configuration of the UE.

[0065] In some aspects, the UE includes: means for selecting, at least in part, one or more new beams for transmitting negative acknowledgments for downlink transmission based on a set of channel quality indicators.

[0066] In some aspects, the UE includes means for selecting the number of the one or more new beams, at least in part based on the configuration of the UE.

[0067] In some aspects, the UE includes: means for determining that a timing offset between the timing of transmitting a measurement report and the timing of transmitting a negative acceptance via the one or more new beams in the candidate beam set satisfies a timing threshold, wherein transmitting a negative acceptance via the one or more new beams in the candidate beam set is based at least in part on determining that the timing offset satisfies the timing threshold.

[0068] In some aspects, the UE includes: means for receiving a downlink control information message indicating that at least one of the one or more new beams is to be used for at least one additional downlink transmission.

[0069] In some aspects, the UE includes: means for transmitting a negative acknowledgment of a downlink transmission via the one or more new beams after determining that no downlink transmission from a base station has been received via the one or more beams, and without receiving from the base station an indication to transmit a negative acknowledgment of the downlink transmission via the one or more new beams.

[0070] In some aspects, the base station includes: means for receiving from the UE a measurement report indicating a set of channel quality indicators for a candidate beam set; means for transmitting downlink transmissions to the UE via one or more beams in the candidate beam set; or means for receiving negative acknowledgments of downlink transmissions from the UE via one or more new beams in the candidate beam set. Means for the base station to perform the operations described herein may include, for example, one or more of the following: transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller / processor 240, memory 242, or scheduler 246.

[0071] In some aspects, the base station includes means for monitoring one or more new beams in the candidate beam set to find negative acknowledgments for downlink transmissions.

[0072] In some aspects, the base station includes means for monitoring the one or more new beams in the candidate beam set and the one or more beams to find negative acknowledgments for downlink transmissions.

[0073] In some aspects, the base station includes means for sequentially monitoring negative reception of downlink transmissions via the one or more new beams and the one or more beams, at least in part based on a set of channel quality indicators.

[0074] In some aspects, the base station includes: means for selecting at least one new beam from the candidate beam set for at least one additional downlink transmission.

[0075] In some aspects, the base station includes: means for selecting at least one new beam from the set of candidate beams, at least in part based on a set of channel quality indicators, for use in the at least one additional downlink transmission.

[0076] In some aspects, the base station includes: means for transmitting a downlink control information message indicating that at least one of the one or more new beams is to be used for the at least one additional downlink transmission.

[0077] In some aspects, the base station includes: means for determining that a timing offset between receiving a measurement report and the timing of receiving a negative acceptance via the one or more new beams in the candidate beam set satisfies a timing threshold, wherein transmitting a downlink control information message indicating that the at least one of the one or more new beams is to be used for the at least one additional downlink transmission is based at least in part on determining that the timing offset satisfies the timing threshold.

[0078] In some aspects, the base station includes means for selecting the number of one or more new beams, at least in part, based on an instruction provided to the UE.

[0079] In some aspects, the base station includes: means for transmitting RRC reconfiguration signaling including an indication to monitor the candidate beam set in order to find one or more reference signals; or means for receiving an indication that the UE is configured to monitor the candidate beam set in order to find the one or more reference signals.

[0080] In some aspects, the base station includes means for selecting one or more beams for transmitting downlink transmissions, based at least in part on the set of channel quality indicators.

[0081] In some aspects, the base station includes means for selecting the number of one or more new beams, at least in part, based on an instruction provided to the UE.

[0082] In some aspects, the base station includes means for receiving a negative acknowledgment of a downlink transmission via one or more new beams after transmitting a downlink transmission to a UE via one or more beams in the candidate beam set, without transmitting an indication to transmit a negative acknowledgment of the downlink transmission via the one or more new beams.

[0083] although Figure 2The boxes in the diagram are interpreted as different components, but the functions described above with respect to these boxes can be implemented using a single hardware component, software component, or combination of components. For example, the functions described with respect to transmit processor 264, receive processor 258, and / or TX MIMO processor 266 can be performed by controller / processor 280 or under the control of controller / processor 280.

[0084] As indicated above, Figure 2 This is provided as an example. Other examples may differ from the one provided. Figure 2 The example described.

[0085] Figure 3 This is a diagram illustrating Example 300 based on the HARQ feedback disclosed herein. For example... Figure 3 As shown, the base station and UE can use one or more beams to transmit downlink transmissions and HARQ feedback.

[0086] like Figure 3 As shown in cycle 310, the base station can transmit downlink transmissions with sequence number 0 via beam 1 and beam 2. The base station can use the Physical Downlink Shared Channel (PDSCH) to transmit downlink transmissions. The PDSCH can be scheduled using semi-persistent scheduling.

[0087] As further illustrated in loop 310, the UE can transmit an acknowledgment (ACK) to indicate that it has received a downlink transmission with sequence number 0. The UE can use the Physical Uplink Control Channel (PUCCH) to transmit the ACK for sequence number 0. The UE can use one or more beams to transmit the ACK for sequence number 0. When the PUCCH and PDSCH are beam reciprocal, the UE can use beam 1 and / or beam 2 to transmit the ACK for sequence number 0. The base station can receive from the UE the ACK indicating that it has received a downlink transmission with sequence number 0.

[0088] As shown in loop 320, the base station can transmit downlink transmission with sequence number 1 via beam 1 and beam 2. As further shown, the UE may not receive the downlink transmission with sequence number 1 (e.g., at least in part due to obstruction, interference, etc.).

[0089] The UE can monitor the timing associated with a downlink transmission having sequence number 1 (e.g., based at least in part on scheduling from the base station). If the UE does not receive a downlink transmission having sequence number 1, the UE can transmit a NACK via beam 1 and / or beam 2. As further shown, the base station may not receive the NACK (e.g., based at least in part on obstruction, interference, etc.).

[0090] In some configurations, the base station can be configured to interpret HARQ feedback moments where no HARQ feedback has been received as ACKs. In these configurations, the base station may interpret moments associated with receiving a HARQ feedback that corresponds to a NACK in cycle 320 as ACKs instead of the expected NACKs. This can be referred to as a NACK-to-ACK error or a HARQ feedback mismatch.

[0091] As shown in loop 330, the base station may transmit a downlink transmission with sequence number 2 via beams 1 and 2, at least in part, based on the failure to receive a NACK from loop 320 (which is intended to indicate that the UE has not received a previous transmission using beams 1 and 2). As further shown, the UE may not have received the downlink transmission with sequence number 2 (e.g., at least in part based on obstruction, interference, etc.).

[0092] The UE can monitor the timing associated with a downlink transmission having sequence number 2 (e.g., based at least in part on scheduling from the base station). Based at least in part on the UE not receiving a downlink transmission having sequence number 2, the UE can transmit a NACK via beam 1 and / or beam 2. As further shown, the base station may not receive the NACK (e.g., based at least in part on obstruction, interference, etc.). Similar to loop 320, the base station can interpret the failure to receive a NACK as an ACK.

[0093] The base station can continue to use beam 1 and beam 2 to transmit downlink data because it is unaware that the UE has not received downlink data. At least in part, based on the UE using beam 1 and / or beam 2 to transmit a NACK (which may be blocked (e.g., by an obstacle along the path associated with the beam)), the UE may not be able to indicate to the base station that it has not received downlink data. Unsuccessful communication attempts between the base station and the UE consume computational, communication, and network resources.

[0094] As indicated above, Figure 3 This is provided as an example. Other examples may differ from the one provided. Figure 3 The example described.

[0095] Figure 4 This is a diagram illustrating Example 400 of the HARQ feedback according to this disclosure. For example... Figure 4 As shown, the base station and UE can use one or more beams to transmit downlink transmissions and HARQ feedback.

[0096] like Figure 4 As shown in cycle 410, the base station can transmit downlink transmissions with sequence number 0 via beam 1 and beam 2. The base station can use a PDSCH to transmit downlink transmissions. The PDSCH can be scheduled using semi-persistent scheduling.

[0097] As further illustrated in loop 410, the UE may transmit a NACK via beam 1 and / or beam 2 to indicate that the UE has not received a downlink transmission with sequence number 0. As shown, the base station may not have received this NACK. The base station may use beam 1 and / or beam 2 to retransmit the downlink transmission with sequence number 0. The base station may determine to retransmit the downlink transmission with sequence number 0 based at least in part on interpreting the timing associated with receiving HARQ feedback for transmitting the downlink transmission with sequence number 0 as a NACK. The base station may interpret the timing as a NACK based at least in part on the absence of any HARQ feedback during that timing and at least in part on the UE's configuration for transmitting ACK or NACK (e.g., the UE is not configured for discontinuous transmissions for HARQ feedback). Additionally or alternatively, the base station may determine to retransmit the downlink transmission with sequence number 0 based at least in part on scheduled retransmissions independent of NACK.

[0098] As further illustrated in loop 410, the UE has no opportunity to transmit HARQ feedback associated with the retransmission of the downlink transmission linked to sequence number 0. The UE may fail to receive the downlink transmission, at least in part, due to interference, beam 1 and / or beam 2 being blocked, etc. Alternatively, the UE may receive (e.g., receive and decode) the downlink transmission, at least in part, based on retransmissions of beam 1 and / or beam 2. In other words, even if the UE does not correctly receive the downlink transmission by any single transmission, the UE can use multiple transmissions to correctly receive the downlink transmission.

[0099] As shown in cycle 420, the base station can transmit the downlink transmission with sequence number 1 via beam 1 and beam 2. The UE can transmit a NACK via beam 1 and / or beam 2 to indicate that the UE has not received the downlink transmission with sequence number 1. As in cycle 410, the base station may not receive this NACK and can use beam 1 and / or beam 2 to retransmit the downlink transmission with sequence number 1. As in cycle 410, the UE has no opportunity during cycle 420 to transmit HARQ feedback associated with the retransmission of the downlink transmission with sequence number 1.

[0100] As shown in loop 430, the base station can transmit the downlink transmission with sequence number 2 via beam 1 and beam 2. The UE can transmit a NACK via beam 1 and / or beam 2 to indicate that the UE has not received the downlink transmission with sequence number 2. As in loop 410, the base station may not receive this NACK and can use beam 1 and / or beam 2 to retransmit the downlink transmission with sequence number 2. As in loop 410, the UE has no opportunity in loop 430 to transmit HARQ feedback associated with the retransmission of the downlink transmission with sequence number 2.

[0101] At least in part, because the UE has no opportunity to transmit HARQ feedback during cycles 410, 420, and 430, the base station may not know whether the UE has received downlink transmissions. Alternatively, the base station may make assumptions that downlink transmissions have been received or not, and incorrect assumptions will consume computing, communication, and / or network resources for detection and correction.

[0102] As indicated above, Figure 4 This is provided as an example. Other examples may differ from the one provided. Figure 4 The example described.

[0103] As mentioned above, during some communications between the base station and the UE, the UE may be unable to provide HARQ feedback to the base station. For example, as in... Figure 3 In this scenario, the UE may be unable to provide HARQ feedback, at least in part, due to obstruction of one or more beams used to transmit HARQ feedback (which can also be used to receive downlink transmissions associated with HARQ feedback). In some communication systems, the base station may be configured to interpret periods of no HARQ feedback received as ACKs, which may be incorrect if the UE transmits a NACK that the base station does not receive. In another example, such as in... Figure 4 In this scenario, the UE may not have the opportunity to transmit HARQ feedback, at least in part, due to the cyclical, finite time budget. If no HARQ feedback is received from the UE, the base station may make an assumption as to whether the UE has received downlink transmissions. If the assumption is incorrect (e.g., a mismatch occurs), the UE and / or the base station will consume computational, communication, and / or network resources to detect and / or correct the incorrect assumption.

[0104] In some aspects described herein, a base station (e.g., base station 110) may transmit one or more reference signals via a candidate beam set. A UE (e.g., UE 120) may monitor the one or more reference signals via the one or more candidate beams. The UE may obtain measurements of the one or more reference signals and generate a measurement report, at least in part based on the measurements, to identify the ranking of the candidate beam set. The UE may transmit the measurement report to the base station to identify the ranking of the candidate beam set. The UE and the base station may communicate via one or more beams in the candidate beam set. The one or more beams may be selected at least in part based on the measurement report.

[0105] The UE can be configured to transmit a NACK for the downlink transmission via one or more new beams from the candidate beam set in response to failure to receive a downlink transmission from the base station. In some aspects, the UE may select the one or more new beams for transmitting the NACK based at least in part on measurements of the one or more reference signals, the measurement reports, and / or the ranking of the candidate beam set, and the base station may be configured to monitor the one or more new beams in the candidate beam set to look for the NACK. In some aspects, the UE and the base station may continue communication via the one or more new beams. In this way, the UE and the base station can switch to at least one new beam for communication after a failed attempt to receive a downlink transmission via one or more current beams. In this way, the UE and the base station can save computational, communication, and / or network resources that would otherwise be used to attempt to transmit and receive additional downlink transmissions via the beam from which the UE failed to receive the downlink transmission.

[0106] Figure 5 This is a diagram illustrating example 500 of beam switching based at least in part on NACK transmission according to this disclosure. As shown, the UE (e.g., UE 120) and the base station (e.g., base station 110) can communicate using one or more of RRC signaling, reference signals (RS), measurement reports, downlink transmissions, HARQ feedback, downlink control information (DCI), etc. In some aspects, the base station and the UE can be part of a wireless network (e.g., wireless network 100).

[0107] like Figure 5 As shown by reference numeral 505 in the accompanying drawings, the base station may transmit RRC signaling to the UE. RRC signaling may include one or more indications for configuration of the UE. In some aspects, RRC signaling may include one or more indications associated with scheduling downlink transmissions (e.g., semi-persistent scheduling). In some aspects, RRC signaling may include an RRC reconfiguration message (RRCReconfiguration or RRCR), an RRC connection establishment message, an RRC reconstruction message, an RRC setup message, or an RRC recovery message, having one or more information elements (e.g., CellGroupConfig) for configuring a cell group. The information elements for configuring the cell group may include a serving cell configuration (e.g., ServingCellConfiguration) having information elements (e.g., CSI-MeasConfig) for configuring channel state information (CSI) measurements. In some aspects, RRC signaling may include an RRC setup (e.g., RRCSetup) message and / or an RRC recovery (e.g., RRCResume) message to configure the UE to monitor the CSI reference signal (CSI-RS).

[0108] In some aspects, RRC signaling may instruct the UE to monitor a candidate beam set to find one or more reference signals when performing reference signal (e.g., CSI-RS) measurements. In some aspects, RRC signaling may instruct the UE to transmit a NACK for downlink transmissions scheduled for one or more current beams via one or more new beams in the candidate beam set. In some aspects, RRC signaling may instruct the UE to transmit a NACK for downlink transmissions scheduled for one or more current beams via one or more new beams in the candidate beam set if a threshold number of downlink transmissions are not received via one or more current beams (e.g., consecutive downlink transmissions of the threshold number, partial downlink transmissions of the threshold number, downlink transmissions of the threshold number received over a time period, etc.). In some aspects, RRC signaling may instruct the UE to transmit a NACK for downlink transmissions scheduled for one or more current beams via one or more new beams in the candidate beam set if the base station misinterprets previously transmitted HARQ feedback.

[0109] In some respects, RRC signaling can instruct the UE to monitor several beams of downlink transmission, several new beams to be used for transmitting NACK, and so on. In other respects, RRC signaling can instruct the procedures for selecting one or more new beams to be used for transmitting NACK. For example, RRC signaling can instruct the UE to use several top-ranked beams from the most recent measurement report (e.g., including one or more current beams or excluding one or more current beams).

[0110] As indicated by reference numeral 510, the UE can be configured at least in part based on this RRC signaling. In some aspects, the UE can be configured to monitor one or more beams in a candidate beam set to search for one or more downlink transmissions. For example, the UE can configure one or more components of the UE to use one or more antennas of the UE to monitor bandwidth portions. In some aspects, the UE can be configured to transmit NACK for downlink transmissions scheduled for one or more current beams via one or more new beams in the candidate beam set. In some aspects, the UE can be configured to receive multiple downlink transmissions during multiple downlink transmission opportunities scheduled via RRC (e.g., at least in part based on semi-persistent scheduling).

[0111] As indicated by reference numeral 515 in the accompanying figure, the UE may transmit an indication of configuration completion. In some aspects, the UE may transmit this indication in an RRC reconfiguration complete (e.g., RRCReconfigurationComplete or RRCRC) message. Based at least in part on receiving the indication of configuration completion, the base station may determine that the UE is configured to perform one or more procedures configured for that UE (e.g., semi-persistent scheduling, monitoring a set of candidate beams to find the one or more reference signals, transmitting NACK for downlink transmissions scheduled for one or more current beams via one or more new beams, etc.).

[0112] As shown by reference numeral 520, a base station may transmit one or more reference signals (e.g., CSI-RS) via a candidate beam set. In some aspects, the base station may use beam sweeping to transmit the one or more reference signals.

[0113] As shown by reference numeral 525, the UE can obtain a set of measurements of the one or more reference signals received on the candidate beam set. In some aspects, the UE can identify the beam identifier associated with the received reference signal based at least in part on the timing of the UE receiving the reference signal and an indication of the time when the base station is scheduled to transmit the one or more reference signals via the candidate beam set.

[0114] As indicated by reference numeral 530, the UE may transmit a measurement report to the base station. The measurement report may include a set of measurements of the obtained reference signals, such as RSRP, RSSI, RSRQ and / or CQI, the ranking of the candidate beam set (e.g., based at least in part on the obtained measurements), and so on.

[0115] As indicated by reference numeral 535, the UE may determine the ranking of the candidate beam set based at least in part on measurements of the reference signal. In some respects, this ranking may be based at least in part on an order of highest to lowest signal quality (e.g., as indicated by RSRP, RSSI, RSRQ, CQI, etc.).

[0116] As indicated by reference numeral 540 in the accompanying figure, the UE can determine the ranking of the candidate beams. In some aspects, the base station can determine the ranking of the candidate beams based at least in part on the ranking indicated in the measurement report, at least in part on the measurement of the reference signal indicated in the measurement report, and so on. In some aspects, the base station and the UE can be configured to determine the ranking of the candidate beam set based at least in part on the same procedures and / or metrics, such that the base station and the UE agree on the ranking.

[0117] In some respects, the UE and the base station can be configured to automatically activate several top-ranked candidate beams for communication between the UE and the base station. In some respects, these top-ranked candidate beams can be based at least in part on RRC signaling, DCI messages, etc.

[0118] As shown by reference numeral 545, a base station may transmit downlink transmissions to a UE. In some aspects, the base station may use a subset of the highest-ranking candidate beams activated to transmit downlink transmissions. In some aspects, the base station may select one or more beams for transmitting downlink transmissions based at least in part on an indication provided to the UE. For example, the base station may select the one or more beams based at least in part on RRC signaling given to the UE indicating that the base station is configured to transmit downlink transmissions via one or more beams with the highest-ranking CQI. In some aspects, the base station may select the number of the one or more beams based at least in part on an indication provided to the UE. For example, the base station may select two as the number of the one or more beams based at least in part on RRC signaling given to the UE indicating that the base station is configured to transmit downlink transmissions via two beams. In some aspects, the base station may transmit a DCI (e.g., a Transmission Configuration Indicator (TCI) state activating the DCI) to indicate that the base station is configured to transmit downlink transmissions via one or more of the activated highest-ranking candidate beams.

[0119] In some respects, the base station may transmit downlink transmissions during a previously scheduled downlink transmission opportunity (e.g., using RRC signaling). In other respects, the UE may not receive downlink transmissions during the downlink transmission opportunity.

[0120] As shown by reference numeral 550, the UE may transmit a NACK via one or more new beams in the candidate beam set as a HARQ feedback for downlink transmissions scheduled for the one or more beams in the candidate beam set. In some aspects, the UE may transmit the NACK via the one or more beams in the candidate beam set (e.g., one or more current beams) and the base station may receive the NACK via the one or more beams.

[0121] In some respects, the UE may transmit NACK via the one or more new beams in the candidate beam set based at least in part on determining the number of downlink transmissions that have not been received via one or more current beams (e.g., consecutive downlink transmissions of the threshold number, downlink transmissions of the threshold portion, downlink transmissions of the threshold number received over a time period, etc.).

[0122] In some respects, the UE may receive an indication that the base station interprets a HARQ feedback timing associated with a previous NACK as an ACK. The UE may transmit a NACK for downlink transmission via one or more new beams, at least in part, based on a mismatch between the base station's interpretation and the previous NACK.

[0123] In some aspects, transmitting a NACK may include performing beam sweeping using one or more new beams. In some aspects, beam sweeping may include transmitting a NACK via the one or more new beams, the one or more current beams, or a combination of the one or more new beams and the one or more current beams. In some aspects, beam sweeping may be performed in an order based at least in part on the ranking of the beam set, the measurement set of the one or more reference signals received using the candidate beam set, etc.

[0124] In some aspects, the UE may select the number of one or more new beams for transmitting NACK based at least in part on indications from the base station (e.g., indications within RRC signaling, DCI, etc.). In some aspects, the UE may select the one or more new beams for transmitting NACK based at least in part on measurements of a reference signal set, measurement reports, beam set rankings, etc. In some aspects, the UE may transmit NACK via these new beams without beam sweeping.

[0125] In some aspects, the UE can determine the timing offset between transmitting the measurement report and the NACK feedback timing. In some aspects, the base station can determine, at least in part, whether to transmit the NACK via the one or more new beams based on the timing offset meeting a threshold. In other words, if the difference between the time when the most recent measurement report is received and the time when the NACK is transmitted meets a threshold (e.g., less than a threshold, less than or equal to a threshold, etc.), the UE can use an agreed beam-sweeping pattern to transmit the NACK. This avoids switching the beam to the one or more new beams, at least in part, based on outdated or invalid information. This saves computational, communication, and / or network resources that would otherwise be consumed by switching the beam to one or more new beams (which are likely to fail in subsequent downlink transmissions but are highly ranked in outdated measurement reports) and using these new beams for subsequent downlink transmissions.

[0126] As indicated by reference numeral 555, the base station may monitor the one or more new beams to look for NACKs. In some aspects, the base station may be configured to monitor the one or more current beams during each HARQ feedback opportunity, after each HARQ feedback opportunity following a threshold number of NACKs, during periodic HARQ feedback opportunities (e.g., at least in part based on time intervals, after a specific number of HARQ feedback opportunities), etc. In some aspects, based at least in part on receiving a NACK associated with a downlink transmission, the base station may determine that it intends to retransmit the downlink transmission via the one or more new beams.

[0127] As indicated by reference numeral 560, a base station may select at least one new beam from the one or more new beams for at least one additional downlink transmission. In some aspects, the base station may select the at least one new beam from the one or more new beams based at least in part on measurement reports, a set of measurements of reference signals (such as RSRP, RSSI, RSRQ and / or CQI, the ranking of the candidate beam set (e.g., at least in part based on the obtained measurements), etc.).

[0128] As shown by reference numeral 565, a base station may transmit a DCI to activate one or more new TCI states. These one or more new TCI states may be associated with at least one of the one or more new beams. In some aspects, the base station may transmit a DCI within a DCI message to activate at least one of the one or more new beams for monitoring downlink transmission retransmissions.

[0129] As indicated by reference numeral 570, the base station may transmit additional downlink transmissions via at least one of the one or more new beams. In some aspects, the base station may retransmit downlink transmissions via at least one of the one or more new beams in the candidate beam set. In some aspects, the base station may retransmit downlink transmissions via at least one of the one or more new beams without transmitting an indication to activate the one or more new beams after a NACK feedback event. In some aspects, the base station may continue to use at least one of the one or more new beams to transmit additional downlink transmissions.

[0130] Based at least in part on switching the beam to at least one new beam for communication after an attempt to receive downlink transmissions via one or more current beams fails, the UE and base station can save computational, communication and / or network resources that would otherwise be used to attempt to transmit and receive additional downlink transmissions by the UE via the one or more current beams from which it failed to receive downlink transmissions.

[0131] As indicated above, Figure 5This is provided as an example. Other examples may differ from the one provided. Figure 5 The example described.

[0132] Figure 6 This is a diagram illustrating an example 600 of beam switching based at least in part on NACK transmissions according to this disclosure. As shown, the UE (e.g., UE 120) and the base station (e.g., base station 110, such as a gNB) can communicate using one or more of RRC signaling, reference signals, measurement reports, downlink transmissions, HARQ feedback, DCI, etc. In some aspects, the base station and the UE can be part of a wireless network (e.g., wireless network 100).

[0133] like Figure 6 As shown in cycle 610, the base station can transmit a downlink transmission with sequence number 0 via beam 1 and beam 2. The base station can use a PDSCH to transmit the downlink transmission. The PDSCH can be scheduled using semi-persistent scheduling. The UE can receive the downlink transmission with sequence number 0 and can determine whether to transmit an ACK or not to transmit HARQ feedback (e.g., at least in part based on the UE being configured for discontinuous transmission (DTX) for HARQ feedback). The base station can interpret an ACK or, in the case of discontinuous transmission, the absence of any HARQ feedback as an indication that the UE received a downlink transmission with sequence number 0 from at least one of beam 1 or beam 2, or from both beam 1 and beam 2 (e.g., if the UE is configured to use soft NACK). In some aspects, the downlink transmission with sequence number 0 may expire at the end of cycle 610.

[0134] As also shown in cycle 610, the base station can transmit RRC signaling, such as RRCR messages, RRC setup messages, RRC recovery messages, etc. RRC signaling can instruct the UE to be configured to monitor a candidate beam set to find one or more reference signals, to transmit NACK via one or more new beams in the candidate beam set, etc. The UE can transmit an indication (e.g., an RRCRC message) that the UE has been configured at least in part based on the RRC signaling.

[0135] As further illustrated in cycle 610, the base station may transmit one or more reference signals (e.g., CSI-RS) via a candidate beam set. The UE may monitor the candidate beam set and obtain measurements of the reference signals. In some aspects, the UE may determine the ranking of the candidate beam set based at least in part on these measurements. In some aspects, the UE may automatically activate several of the highest-ranking candidate beams to communicate with the base station.

[0136] The UE can transmit a measurement report (MR) to the base station. In some aspects, the base station can determine the ranking of the candidate beam set based at least in part on measurements, indications of the ranking of the candidate beam set within the measurement report, and so on. In this way, the base station and the UE can agree on the ranking of the candidate beam set. In some aspects, the base station can automatically activate the highest-ranking candidate beams to communicate with the UE.

[0137] As shown in loop 620, the base station can transmit a downlink transmission with sequence number 1 via beam 1 and beam 2. The downlink transmission may include a DCI indicating TCI state activation (e.g., if the UE is not configured to automatically activate the several highest-ranking candidate beams to communicate with the base station). In some aspects, the downlink transmission may include an indication of the interpretation of HARQ feedback from a previous downlink transmission (e.g., an ACK for a downlink transmission with sequence number 0). Beam 1 and beam 2 may be blocked, and the UE may not receive the downlink transmission with sequence number 1 during the scheduled time for receiving the downlink transmission.

[0138] The UE may use one or more new beams (e.g., beam 3 and / or beam 4) to transmit a NACK (e.g., using PUCCH) to indicate that the UE has not received a downlink transmission with sequence number 1. In some aspects, the UE has not received the downlink transmission with sequence number 1 at least in part due to interference (e.g., from one or more other cells), obstruction, etc. In some aspects, the base station may receive the NACK from the UE via beam 3 and / or beam 4.

[0139] As also shown in loop 620, the base station may retransmit a downlink transmission with sequence number 1 via at least one of the one or more new beams based at least in part on receiving a NACK via at least one of the one or more new beams (e.g., beam 3 and beam 4). In some aspects, the downlink transmission may include DCI to indicate the activation of a new TCI state (e.g., if the UE is not configured to automatically activate the one or more new beams through which the UE transmits a NACK).

[0140] The UE can receive retransmissions of downlink transmissions with sequence number 1 and can determine whether to transmit an ACK or not to transmit HARQ feedback. The base station can interpret the absence of any HARQ feedback, or, in the case of discontinuous transmissions configured for HARQ feedback, as an indication that the UE received a downlink transmission with sequence number 1 from at least one of beams 3 or 4, or from both beams 3 and 4 (e.g., if the UE is configured to use soft NACK).

[0141] The base station and the UE can use the one or more new beams to convey at least one additional message. For example, the base station can transmit a downlink transmission with sequence number 2 via beams 3 and 4. The UE can monitor beams 3 and 4 to locate the downlink transmission with sequence number 2 and transmit a HARQ feedback for the downlink transmission with sequence number 2.

[0142] As indicated above, Figure 6 This is provided as an example. Other examples may differ from the one provided. Figure 6 The example described.

[0143] Figure 7 This is a diagram illustrating an example 700 of beam switching based at least in part on NACK transmissions according to this disclosure. As shown, the UE (e.g., UE 120) and the base station (e.g., base station 110, such as a gNB) can communicate using one or more of RRC signaling, reference signals, measurement reports, downlink transmissions, HARQ feedback, DCI, etc. In some aspects, the base station and the UE can be part of a wireless network (e.g., wireless network 100).

[0144] like Figure 7 As shown in cycle 710, the base station can transmit a downlink transmission with sequence number 0 via beam 1 and beam 2. The base station can use a PDSCH to transmit the downlink transmission. The PDSCH can be scheduled using semi-persistent scheduling. The UE can receive the downlink transmission with sequence number 0 and can determine whether to transmit an ACK or not to transmit HARQ feedback. The base station can interpret an ACK, or in the case of discontinuous transmission, the absence of any HARQ feedback, as an indication that the UE has received a downlink transmission with sequence number 0 from at least one of beam 1 or beam 2, or from both beam 1 and beam 2 (e.g., if the UE is configured to use soft ACK). In some aspects, the downlink transmission with sequence number 0 may expire at the end of cycle 710.

[0145] As also shown in loop 710, the base station can transmit RRC signaling, such as RRCR messages, RRC setup messages, RRC recovery messages, etc. RRC signaling can instruct the UE to be configured to monitor a candidate beam set to find one or more reference signals, to transmit NACK via one or more new beams in the candidate beam set, etc. The UE can transmit an indication (e.g., an RRCRC message) that the UE has been configured at least in part based on the RRC signaling.

[0146] As further illustrated in cycle 710, the base station may transmit one or more reference signals (e.g., CSI-RS) via a candidate beam set. The UE may monitor the candidate beam set and obtain measurements of the reference signals. In some aspects, the UE may determine the ranking of the candidate beam set based at least in part on these measurements. In some aspects, the UE may automatically activate several top-ranked candidate beams to communicate with the base station.

[0147] The UE can transmit measurement reports to the base station. In some aspects, the base station can determine the ranking of the candidate beam set based at least in part on measurements, indications of the ranking of the candidate beam set within the measurement report, and so on. In this way, the base station and the UE can have synchronized rankings of the candidate beam sets. In some aspects, the base station can automatically activate the highest-ranking candidate beams to communicate with the UE.

[0148] As shown in loop 720, the base station can transmit a downlink transmission with sequence number 1 via beam 1 and beam 2. The downlink transmission may include a DCI indicating TCI state activation (e.g., if the UE is not configured to automatically activate the several highest-ranking candidate beams to communicate with the base station). In some aspects, the downlink transmission may include an indication of the interpretation of HARQ feedback from a previous downlink transmission (e.g., an ACK for a downlink transmission with sequence number 0). Beam 1 and beam 2 may be blocked, and the UE may not receive the downlink transmission with sequence number 1 during the scheduled time for receiving the downlink transmission.

[0149] As also shown in loop 720, the UE may perform beam sweeping using one or more new beams (e.g., beam 3 and beam 4) and / or beam 1 and beam 2. In some aspects, the UE may transmit a NACK for a downlink transmission with sequence number 1 via the one or more new beams and / or beam 1 and beam 2 in order at least in part based on measurements of one or more reference signals received using the candidate beam set, the ranking of the candidate beam set, measurement reports, etc. (e.g., chronological order). In some aspects, the UE may be configured to transmit NACK simultaneously via multiple beams, and the base station may simultaneously monitor multiple candidate beams to search for NACK.

[0150] In some aspects, the base station may use at least one of the one or more new beams to retransmit downlink transmissions with sequence number 1. In some aspects, the base station may transmit a DCI to indicate TCI state activation (e.g., if the UE is not configured to automatically activate several highest-ranking candidate beams to communicate with the base station). In some aspects, the UE may use the one or more new beams to transmit an ACK or may determine not to transmit HARQ feedback (e.g., at least in part based on the DTX configured for HARQ feedback by the UE).

[0151] The base station can interpret ACK or the absence of any HARQ feedback as an indication that the UE has received a downlink transmission with sequence number 1 from at least one of beams 3 and 4, or from both beams 3 and 4 (e.g., if the UE is configured to use soft NACK).

[0152] The base station and the UE can use the one or more new beams to convey at least one additional message. For example, the base station can transmit a downlink transmission with sequence number 2 via beams 3 and 4. The UE can monitor beams 3 and 4 to locate the downlink transmission with sequence number 2 and transmit a HARQ feedback for the downlink transmission with sequence number 2.

[0153] As indicated above, Figure 7 This is provided as an example. Other examples may differ from the one provided. Figure 7 The example described.

[0154] Figure 8 This is a diagram illustrating an example procedure 800 performed by a UE according to this disclosure. Example procedure 800 is an example in which a UE (e.g., UE 120, etc.) performs operations associated with beam switching based at least in part on NACK transmissions.

[0155] like Figure 8 As shown, in some aspects, process 800 may include transmitting a measurement report indicating a set of CQIs for a candidate beam set (block 810). For example, a UE (e.g., using controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, etc.) may transmit a measurement report indicating a set of CQIs for a candidate beam set, as described above.

[0156] like Figure 8 As further shown, in some aspects, process 800 may include: determining that no downlink transmission from the base station has been received via one or more beams in the candidate beam set (block 820). For example, the UE (e.g., using antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, controller / processor 280, etc.) may determine that no downlink transmission from the base station has been received via one or more beams in the candidate beam set, as described above.

[0157] like Figure 8As further shown, in some aspects, process 800 may include transmitting a NACK for the downlink transmission via one or more new beams from the candidate beam set (block 830). For example, the UE (e.g., using controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, etc.) may transmit a NACK for the downlink transmission via one or more new beams from the candidate beam set, as described above.

[0158] Process 800 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.

[0159] In a first aspect, transmitting NACK for downlink transmission via the one or more new beams in the candidate beam set includes: performing beam sweeping using the one or more new beams.

[0160] In the second aspect, either alone or in combination with the first aspect, performing beam sweeping includes: using one or more new beams and the one or more new beams to perform the beam sweeping.

[0161] In a third aspect, performing beam sweeping, either alone or in combination with one or more of the first and second aspects, includes sequentially transmitting NACKs for downlink transmissions via the one or more new beams and the one or more beams in an order at least partially based on the CQI set.

[0162] In a fourth aspect, either alone or in combination with one or more of the first to third aspects, process 800 includes: transmitting a NACK for downlink transmission via the one or more beams in the candidate beam set; and receiving an indication that the base station interprets a HARQ feedback timing associated with the NACK as an acceptance, and transmitting the NACK for downlink transmission via the one or more new beams based at least in part on a mismatch between the base station's interpretation and the NACK.

[0163] In a fifth aspect, either alone or in combination with one or more of the first to fourth aspects, process 800 includes: receiving RRC reconfiguration, RRC connection establishment, RRC reconstruction, RRC setup, or RRC recovery signaling including an indication to monitor the candidate beam set to search for one or more reference signals; configuring the UE to monitor the candidate beam set to search for the one or more reference signals; and transmitting an indication that the UE is configured to monitor the candidate beam set to search for the one or more reference signals.

[0164] In a sixth aspect, alone or in combination with one or more of the first to fifth aspects, process 800 includes: obtaining measurements of the one or more reference signals received on the candidate beam set; and determining a ranking of the candidate beams in the candidate beam set based at least in part on the measurements of the one or more reference signals.

[0165] In the seventh aspect, alone or in combination with one or more of the first to sixth aspects, process 800 includes: selecting one or more beams for receiving downlink transmissions based at least in part on the CQI set.

[0166] In the eighth aspect, alone or in combination with one or more of the first to seventh aspects, process 800 includes: selecting the number of the one or more beams based at least in part on the configuration of the UE.

[0167] In the ninth aspect, either alone or in combination with one or more of the first to eighth aspects, process 800 includes: selecting, at least in part, the one or more new beams for transmitting NACK for downlink transmission based on the CQI set.

[0168] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, process 800 includes: selecting the number of the one or more new beams based at least in part on the configuration of the UE.

[0169] In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, process 800 includes: determining that the timing offset between transmitting the measurement report and the timing for transmitting NACK via the one or more new beams in the candidate beam set satisfies a timing threshold, and that transmitting NACK via the one or more new beams in the candidate beam set is based at least in part on determining that the timing offset satisfies the timing threshold.

[0170] In the twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, process 800 includes: receiving a DCI message indicating that at least one of the one or more new beams is to be used for at least one additional downlink transmission.

[0171] In the thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, the at least one additional downlink transmission includes retransmission of the downlink transmission.

[0172] In the fourteenth aspect, transmitting a NACK for a downlink transmission via the one or more new beams in the candidate beam set, either alone or in combination with one or more of the first to thirteenth aspects, includes: transmitting a NACK for a downlink transmission via the one or more new beams after determining that no downlink transmission from the base station has been received via the one or more beams, without receiving an instruction from the base station to transmit a NACK for the downlink transmission via the one or more new beams.

[0173] although Figure 8 An example box of process 800 is shown, but in some respects, process 800 may include... Figure 8 The boxes depicted in the diagram are compared to additional boxes, fewer boxes, different boxes, or boxes arranged differently. Additionally or alternatively, two or more boxes in process 800 can be executed in parallel.

[0174] Figure 9 This is a diagram illustrating an example process 900 performed by a base station according to this disclosure. Example process 900 is an example in which a base station (e.g., base station 110, etc.) performs operations associated with beam switching based at least in part on NACK transmissions.

[0175] like Figure 9 As shown, in some aspects, process 900 may include receiving from the UE a measurement report indicating a set of CQIs for a candidate beam set (block 910). For example, a base station (e.g., using antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, etc.) may receive from the UE a measurement report indicating a set of CQIs for a candidate beam set, as described above.

[0176] like Figure 9 As further shown, in some aspects, process 900 may include transmitting downlink transmissions to the UE via one or more beams from the candidate beam set (block 920). For example, a base station (e.g., using controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, etc.) may transmit downlink transmissions to the UE via one or more beams from the candidate beam set, as described above.

[0177] like Figure 9As further shown, in some aspects, process 900 may include receiving a NACK for the downlink transmission from the UE via one or more new beams in the candidate beam set (block 930). For example, a base station (e.g., using antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, etc.) may receive a NACK for the downlink transmission from the UE via one or more new beams in the candidate beam set, as described above.

[0178] Process 900 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.

[0179] In a first aspect, receiving a NACK for a downlink transmission via the one or more new beams in the candidate beam set includes: monitoring the one or more new beams in the candidate beam set to find a NACK for a downlink transmission.

[0180] In a second aspect, receiving a NACK for a downlink transmission via the one or more new beams in the candidate beam set, either alone or in combination with the first aspect, includes: monitoring the one or more new beams in the candidate beam set and the one or more beams to look for a NACK for a downlink transmission.

[0181] In a third aspect, monitoring the one or more new beams and the one or more beams, either alone or in combination with one or more of the first and second aspects, includes: sequentially transmitting NACKs for downlink transmissions via the one or more new beams and the one or more beams in an order at least partially based on the CQI set.

[0182] In the fourth aspect, alone or in combination with one or more of the first to third aspects, process 900 includes: selecting at least one new beam from the candidate beam set for use in at least one additional downlink transmission.

[0183] In the fifth aspect, selecting the at least one new beam from the one or more new beams in the candidate beam set for the at least one additional downlink transmission, either alone or in combination with one or more of the first to fourth aspects, comprises: selecting the at least one new beam from the one or more new beams in the candidate beam set for the at least one additional downlink transmission based at least in part on the CQI set.

[0184] In the sixth aspect, alone or in combination with one or more of the first to fifth aspects, process 900 includes: transmitting a DCI message indicating that at least one of the one or more new beams is to be used for the at least one additional downlink transmission.

[0185] In the seventh aspect, alone or in combination with one or more of the first to sixth aspects, process 900 includes: determining that the timing offset between receiving the measurement report and the timing for receiving NACK via the one or more new beams in the candidate beam set satisfies a timing threshold, and transmitting a DCI message indicating that the at least one new beam in the one or more new beams is to be used for the at least one additional downlink transmission based at least in part on determining that the timing offset satisfies the timing threshold.

[0186] In the eighth aspect, alone or in combination with one or more of the first to seventh aspects, the at least one additional downlink transmission includes retransmission of the downlink transmission.

[0187] In the ninth aspect, alone or in combination with one or more of the first to eighth aspects, process 900 includes: selecting the number of the one or more new beams based at least in part on an instruction provided to the UE.

[0188] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, process 900 includes: transmitting RRC reconfiguration signaling including an indication to monitor the candidate beam set to find one or more reference signals; and receiving an indication that the UE is configured to monitor the candidate beam set to find the one or more reference signals.

[0189] In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, process 900 includes: selecting one or more beams for transmitting downlink transmissions based at least in part on the CQI set.

[0190] In the twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, process 900 includes: selecting the number of the one or more beams based at least in part on an instruction provided to the UE.

[0191] In the thirteenth aspect, receiving a NACK for a downlink transmission via the one or more new beams in the candidate beam set, either alone or in combination with one or more of the first to twelfth aspects, includes receiving a NACK for the downlink transmission via the one or more new beams in the candidate beam set without transmitting an instruction to transmit a NACK for the downlink transmission via the one or more new beams.

[0192] although Figure 9 An example box of process 900 is shown, but in some respects, process 900 may include... Figure 9 The boxes depicted in the diagram are compared to additional boxes, fewer boxes, different boxes, or boxes arranged differently. Additionally or alternatively, two or more boxes in process 900 can be executed in parallel.

[0193] The following provides an overview of some aspects of this disclosure:

[0194] Aspect 1: A wireless communication method performed by a user equipment (UE) includes: transmitting a measurement report indicating a set of channel quality indicators for a set of candidate beams; determining that no downlink transmission from a base station has been received via one or more beams in the set of candidate beams; and transmitting a negative acknowledgment of the downlink transmission via one or more new beams in the set of candidate beams.

[0195] Aspect 2: The method of aspect 1, wherein transmitting the negative acknowledgment for the downlink transmission via the one or more new beams in the candidate beam set comprises: performing beam sweeping using the one or more new beams.

[0196] Aspect 3: The method as described in aspect 2, wherein performing the beam sweep includes: using one or more new beams and the one or more new beams to perform the beam sweep.

[0197] Aspect 4: The method of aspect 3, wherein performing the beam sweep comprises: sequentially transmitting the negative acknowledgment for the downlink transmission via the one or more new beams and the one or more beams in order at least partially based on the channel quality indicator set.

[0198] Aspect 5: The method of any of Aspects 1-4 further includes: transmitting the negative acceptance for the downlink transmission via one or more beams in the candidate beam set; and receiving an indication that the base station interprets a Hybrid Automatic Repeat Request (HARQ) feedback timing associated with the negative acceptance as acceptance, wherein transmitting the negative acceptance for the downlink transmission via the one or more new beams is at least in part based on a mismatch between the base station's interpretation and the negative acceptance.

[0199] Aspect 6: The method of any one of Aspects 1-5 further includes: receiving Radio Resource Control (RRC) reconfiguration, RRC connection establishment, RRC re-establishment, RRC establishment, or RRC recovery signaling including an indication to monitor the candidate beam set to search for one or more reference signals; configuring the UE to monitor the candidate beam set to search for the one or more reference signals; and transmitting an indication that the UE is configured to monitor the candidate beam set to search for the one or more reference signals.

[0200] Aspect 7: The method of aspect 6 further includes: obtaining measurements of the one or more reference signals received on the candidate beam set; and determining the ranking of the candidate beams in the candidate beam set based at least in part on the measurements of the one or more reference signals.

[0201] Aspect 8: The method of any of Aspects 1-7 further includes: selecting the one or more beams for receiving the downlink transmission based at least in part on the set of channel quality indicators.

[0202] Aspect 9: The method of any of Aspects 1-8 further includes: selecting the number of the one or more beams based at least in part on the configuration of the UE.

[0203] Aspect 10: The method of any of Aspects 1-9 further includes: selecting the one or more new beams for transmitting the negative acknowledgment for the downlink transmission based at least in part on the set of channel quality indicators.

[0204] Aspect 11: The method of any of Aspects 1-10 further includes: selecting the number of the one or more new beams based at least in part on the configuration of the UE.

[0205] Aspect 12: The method of any of Aspects 1-11 further comprises: determining that a timing offset between transmitting the measurement report and the timing for transmitting the negative acceptance via the one or more new beams in the candidate beam set satisfies a timing threshold, wherein transmitting the negative acceptance via the one or more new beams in the candidate beam set is at least partially based on determining that the timing offset satisfies the timing threshold.

[0206] Aspect 13: The method of any of Aspects 1-12 further includes: receiving a downlink control information message indicating that at least one of the one or more new beams is to be used for at least one additional downlink transmission.

[0207] Aspect 14: The method as described in aspect 13, wherein the at least one additional downlink transmission includes a retransmission of the downlink transmission.

[0208] Aspect 15: The method of any of Aspects 1-14, wherein transmitting the negative acknowledgment for the downlink transmission via the one or more new beams in the candidate beam set comprises: transmitting the negative acknowledgment for the downlink transmission via the one or more new beams after determining that the downlink transmission from the base station has not been received via the one or more beams, without receiving an instruction from the base station to transmit the negative acknowledgment for the downlink transmission via the one or more new beams.

[0209] Aspect 16: A wireless communication method performed by a base station, comprising: receiving from a user equipment (UE) a measurement report indicating a set of channel quality indicators for a set of candidate beams; transmitting a downlink transmission to the UE via one or more beams in the set of candidate beams; and receiving from the UE a negative acknowledgment of the downlink transmission via one or more new beams in the set of candidate beams.

[0210] Aspect 17: The method of aspect 16, wherein receiving the negative acknowledgment for the downlink transmission via the one or more new beams in the candidate beam set comprises: monitoring the one or more new beams in the candidate beam set to find the negative acknowledgment for the downlink transmission.

[0211] Aspect 18: The method of any of Aspects 16-17, wherein receiving the negative acknowledgment for the downlink transmission via the one or more new beams in the candidate beam set comprises: monitoring the one or more new beams in the candidate beam set and the one or more beams to find the negative acknowledgment for the downlink transmission.

[0212] Aspect 19: The method of aspect 18, wherein monitoring the one or more new beams and the one or more beams comprises: sequentially monitoring the negative acknowledgment for the downlink transmission via the one or more new beams and the one or more beams in order at least partially based on the channel quality indicator set.

[0213] Aspect 20: The method of any of Aspects 16-19 further includes: selecting at least one new beam from the candidate beam set for at least one additional downlink transmission.

[0214] Aspect 21: The method of aspect 20, wherein selecting at least one new beam from the one or more new beams in the candidate beam set for the at least one additional downlink transmission comprises: selecting at least one new beam from the one or more new beams in the candidate beam set for the at least one additional downlink transmission based at least in part on the channel quality indicator set.

[0215] Aspect 22: The method of aspect 20 further includes: transmitting a downlink control information message indicating that at least one of the one or more new beams is to be used for the at least one additional downlink transmission.

[0216] Aspect 23: The method of aspect 22 further includes: determining that the timing offset between receiving the measurement report and the timing for receiving the negative acknowledgment via the one or more new beams in the candidate beam set satisfies a timing threshold, wherein transmitting the downlink control information message indicating that the at least one new beam in the one or more new beams is to be used for the at least one additional downlink transmission is based at least in part on determining that the timing offset satisfies the timing threshold.

[0217] Aspect 24: The method as described in aspect 22, wherein the at least one additional downlink transmission includes a retransmission of the downlink transmission.

[0218] Aspect 25: The method of any of Aspects 16-24 further includes: selecting the number of the one or more new beams based at least in part on an instruction provided to the UE.

[0219] Aspect 26: The method of any of Aspects 16-25 further comprises: transmitting radio resource control (RRC) reconfiguration signaling including an indication to monitor the candidate beam set to find one or more reference signals; and receiving an indication that the UE is configured to monitor the candidate beam set to find the one or more reference signals.

[0220] Aspect 27: The method of any of Aspects 16-26 further includes: selecting the one or more beams for transmitting the downlink transmission based at least in part on the set of channel quality indicators.

[0221] Aspect 28: The method of any of Aspects 16-27 further includes: selecting the number of the one or more beams based at least in part on an instruction provided to the UE.

[0222] Aspect 29: The method of any of Aspects 16-28, wherein receiving the negative acknowledgment for the downlink transmission via the one or more new beams in the candidate beam set comprises: receiving the negative acknowledgment for the downlink transmission via the one or more new beams after transmitting the downlink transmission to the UE via the one or more beams in the candidate beam set without transmitting an indication to transmit the negative acknowledgment for the downlink transmission via the one or more new beams.

[0223] Aspect 30: 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 the methods described in one or more of aspects 1-29.

[0224] Aspect 31: An apparatus for wireless communication, comprising a memory and one or more processors coupled to the memory, the memory and the one or more processors being configured to perform the methods described in one or more aspects of aspects 1-29.

[0225] Aspect 32: An apparatus for wireless communication, comprising at least one means for performing the method as described in one or more of aspects 1-29.

[0226] Aspect 33: A non-transient computer-readable medium storing code for wireless communication, the code including instructions executable by a processor to perform the methods described in one or more of aspects 1-29.

[0227] Aspect 34: A non-transient computer-readable medium storing a set of instructions for wireless communication, the set of instructions including one or more instructions which, when executed by one or more processors of a device, cause the device to perform the methods described in one or more aspects of aspects 1-29.

[0228] The foregoing disclosure provides explanations and descriptions, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the foregoing disclosure or may be obtained through practice.

[0229] As used herein, the term "component" is intended to be broadly interpreted as hardware and / or a combination of hardware and software. "Software" should be broadly interpreted as instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, and / or functions, whether referred to as software, firmware, middleware, microcode, hardware description languages, or other terms. As used herein, processors are implemented using hardware and / or a combination of hardware and software. It will be apparent 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 limited in any way. Thus, the operation and behavior of these systems and / or methods are described herein without reference to any specific software code—it is understood that software and hardware can be designed to implement these systems and / or methods, at least in part, based on the descriptions herein.

[0230] As used in this article, depending on the context, a 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.

[0231] Although specific combinations of features are described in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of aspects. In fact, many of these features can be combined in ways not specifically described in the claims and / or not disclosed in the specification. Although each dependent claim listed below may be directly subordinated to only one claim, the disclosure of aspects includes each dependent claim being combined with each other claim in this set of claims. As used herein, the phrase “at least one of” refers to any combination of these items, including single members. As an example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc, as well as any combination having multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0232] The elements, actions, or instructions used herein should not be construed as critical or necessary unless explicitly stated otherwise. Furthermore, as used herein, the articles “a” and “a certain” are intended to include one or more items and may be used interchangeably with “one or more.” Additionally, as used herein, the article “the” is intended to include one or more items referenced in conjunction with the article “the” and may be used interchangeably with “one or more.” Furthermore, as used herein, the terms “set” (collection, group) and “group” are intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items) and may be used interchangeably with “one or more.” Where only one item is intended, the phrase “only one” or similar language is used. Moreover, as used herein, the terms “have,” “contain,” “include,” etc., are intended to be open-ended terms. Furthermore, the phrase “based on” is intended to mean “at least partially based on” unless otherwise explicitly stated. Moreover, as used herein, the term “or” is intended to be inclusive when used in a sequence and may be used interchangeably with “and / or” unless otherwise explicitly stated (e.g., in combination with “either of” or “only one of”).

Claims

1. A user equipment (UE) for wireless communication, comprising: a memory; and one or more processors, operatively coupled to the memory, configured to: transmit a measurement report indicating a set of channel quality indicators for a set of candidate beams; determine that a downlink transmission from a base station is not received via one or more beams of the set of candidate beams; transmit, via one or more new beams of the set of candidate beams, a negative acknowledgement for the downlink transmission; and receive a downlink control information message indicating that at least one new beam of the one or more new beams is to be used for at least one additional downlink transmission, where the at least one additional downlink transmission comprises a retransmission of the downlink transmission.

2. The UE of claim 1, wherein, the one or more processors, when transmitting, via the one or more new beams of the set of candidate beams, the negative acknowledgement for the downlink transmission, are configured to: perform a beam sweep using the one or more new beams.

3. The UE of claim 2, wherein, the one or more processors, when performing the beam sweep, are configured to: perform the beam sweep using the one or more new beams and the one or more beams.

4. The UE of claim 3, wherein, the one or more processors, when performing the beam sweep, are configured to: sequentially transmit, via the one or more new beams and the one or more beams, the negative acknowledgement for the downlink transmission in an order that is based at least in part on the set of channel quality indicators.

5. The UE of claim 1, wherein, the one or more processors are further configured to: transmit, via the one or more beams of the set of candidate beams, the negative acknowledgement for the downlink transmission; and receive an indication that a hybrid automatic repeat request (HARQ) feedback occasion associated with the negative acknowledgement is to be interpreted as an acknowledgement, where transmitting, via the one or more new beams, the negative acknowledgement for the downlink transmission is based at least in part on a mismatch between an interpretation by the base station and the negative acknowledgement.

6. The UE of claim 1, wherein, the one or more processors are further configured to: receive radio resource control (RRC) reconfiguration, RRC connection setup, RRC reestablishment, RRC setup, or RRC resume signaling including an indication to monitor the set of candidate beams for one or more reference signals; configure the UE to monitor the set of candidate beams for the one or more reference signals; and transmit an indication that the UE is configured to monitor the set of candidate beams for the one or more reference signals.

7. The UE of claim 6, wherein, the one or more processors are further configured to: obtain measurements of the one or more reference signals received on the set of candidate beams; and determine a ranking of candidate beams of the set of candidate beams based at least in part on the measurements of the one or more reference signals.

8. The UE of claim 1, wherein, the one or more processors are further configured to: select the one or more beams for receiving the downlink transmission based at least in part on the set of channel quality indicators.

9. The UE of claim 1, wherein, the one or more processors are further configured to: selecting the one or more new beams for transmitting the negative acknowledgement for the downlink transmission based at least in part on the set of channel quality indicators.

10. The UE of claim 1, wherein, the one or more processors are further configured to: determine that a timing offset between transmitting the measurement report and a timing of transmitting the negative acknowledgement via the one or more new beams of the set of candidate beams satisfies a timing threshold, where transmitting the negative acknowledgement via the one or more new beams of the set of candidate beams is based at least in part on determining that the timing offset satisfies the timing threshold.

11. The UE of claim 1, wherein, the one or more processors, when transmitting the negative acknowledgement for the downlink transmission via the one or more new beams of the set of candidate beams, are configured to: transmit the negative acknowledgement for the downlink transmission via the one or more new beams without receiving an indication from the base station to transmit the negative acknowledgement for the downlink transmission via the one or more new beams after determining that the downlink transmission from the base station is not received via the one or more beams.

12. A method of wireless communication performed by a user equipment (UE), comprising: transmitting a measurement report indicating a set of channel quality indicators for a set of candidate beams; determining that a downlink transmission from a base station is not received via one or more beams of the set of candidate beams; transmitting a negative acknowledgement for the downlink transmission via one or more new beams of the set of candidate beams; and receiving a downlink control information message indicating that at least one new beam of the one or more new beams is to be used for at least one additional downlink transmission, where the at least one additional downlink transmission comprises a retransmission of the downlink transmission.

13. The method of claim 12, wherein, transmitting the negative acknowledgement for the downlink transmission via the one or more new beams of the set of candidate beams comprises: performing a beam sweep using the one or more new beams.

14. The method of claim 13, wherein, performing the beam sweep comprises: performing the beam sweep using the one or more new beams and the one or more beams.

15. The method of claim 14, wherein, performing the beam sweep comprises: sequentially transmitting the negative acknowledgement for the downlink transmission via the one or more new beams and the one or more beams in an order based at least in part on the set of channel quality indicators.

16. The method of claim 12, further comprising: transmitting the negative acknowledgement for the downlink transmission via the one or more beams of the set of candidate beams; and receiving an indication that the base station interprets a hybrid automatic repeat request (HARQ) feedback occasion associated with the negative acknowledgement as an acknowledgement, where transmitting the negative acknowledgement for the downlink transmission via the one or more new beams is based at least in part on a mismatch between the interpretation by the base station and the negative acknowledgement.

17. The method of claim 12, further comprising: receiving radio resource control (RRC) reconfiguration, RRC connection setup, RRC reestablishment, RRC setup, or RRC resume signaling including an indication to monitor the set of candidate beams for one or more reference signals; configuring the UE to monitor the set of candidate beams for the one or more reference signals; and transmitting an indication that the UE is configured to monitor the set of candidate beams for the one or more reference signals.

18. The method of claim 17, further comprising: obtaining measurements of the one or more reference signals received on the set of candidate beams; and determining a ranking of candidate beams in the set of candidate beams based at least in part on the measurements of the one or more reference signals.

19. The method of claim 12, further comprising: selecting the one or more beams for receiving the downlink transmission based at least in part on the set of channel quality indicators.

20. The method of claim 12, further comprising: selecting the one or more new beams for transmitting the negative acknowledgement for the downlink transmission based at least in part on the set of channel quality indicators.

21. The method of claim 12, further comprising: determining that a timing offset between transmitting the measurement report and an occasion for transmitting the negative acknowledgement via the one or more new beams of the set of candidate beams satisfies a timing threshold, where transmitting the negative acknowledgement via the one or more new beams of the set of candidate beams is based at least in part on determining that the timing offset satisfies the timing threshold.

22. The method of claim 12, wherein, transmitting the negative acknowledgement for the downlink transmission via the one or more new beams of the set of candidate beams comprises: transmitting the negative acknowledgement for the downlink transmission via the one or more new beams without receiving an indication from the base station to transmit the negative acknowledgement for the downlink transmission via the one or more new beams after determining that the downlink transmission from the base station is not received via the one or more beams.

23. A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising: one or more instructions that, when executed by one or more processors of a user equipment (UE), cause the UE to: transmit a measurement report indicating a set of channel quality indicators for a set of candidate beams; determine that a downlink transmission from a base station is not received via one or more beams of the set of candidate beams; transmit a negative acknowledgement for the downlink transmission via one or more new beams of the set of candidate beams; and receive a downlink control information message indicating that at least one new beam of the one or more new beams is to be used for at least one additional downlink transmission, where the at least one additional downlink transmission comprises a retransmission of the downlink transmission.

24. The non-transitory computer readable medium of claim 23, wherein, The one or more beams of the candidate beam set. The one or more beams of the candidate beam set.

25. An apparatus for wireless communication, comprising: means for transmitting a measurement report indicating a set of channel quality indicators for a set of candidate beams; means for determining that a downlink transmission from a base station was not received via one or more beams of the set of candidate beams; means for transmitting a negative acknowledgement for the downlink transmission via one or more new beams of the set of candidate beams; and means for receiving a downlink control information message indicating that at least one new beam of the one or more new beams is to be used for at least one additional downlink transmission, wherein the at least one additional downlink transmission comprises a retransmission of the downlink transmission.

26. The apparatus of claim 25, wherein, The means for transmitting the negative acknowledgement for the downlink transmission via the one or more new beams of the set of candidate beams comprises: means for performing a beam sweep using the one or more new beams.

27. The apparatus of claim 26, wherein, The means for performing the beam sweep comprises: means for performing the beam sweep using the one or more new beams and the one or more beams.

28. The apparatus of claim 27, wherein, The means for performing the beam sweep comprises: means for sequentially transmitting the negative acknowledgement for the downlink transmission via the one or more new beams and the one or more beams in an order based at least in part on the set of channel quality indicators.

29. The apparatus of claim 25, further comprising: means for transmitting the negative acknowledgement for the downlink transmission via the one or more beams of the set of candidate beams; and means for receiving an indication that a hybrid automatic repeat request (HARQ) feedback occasion associated with the negative acknowledgement is to be interpreted as an acknowledgement, wherein transmitting the negative acknowledgement for the downlink transmission via the one or more new beams is based at least in part on a mismatch between an interpretation by the base station and the negative acknowledgement.

30. The apparatus of claim 25, further comprising: means for receiving radio resource control (RRC) reconfiguration, RRC connection setup, RRC reestablishment, RRC setup, or RRC resume signaling including an indication to monitor the set of candidate beams for one or more reference signals; means for configuring a UE to monitor the set of candidate beams for the one or more reference signals; and means for transmitting an indication that the UE is configured to monitor the set of candidate beams for the one or more reference signals.

31. The apparatus of claim 30, further comprising: means for obtaining measurements of the one or more reference signals received on the set of candidate beams; and means for determining a ranking of candidate beams in the set of candidate beams based at least in part on measurements of the one or more reference signals.

32. The apparatus of claim 25, further comprising: means for selecting the one or more beams for receiving the downlink transmission based at least in part on the set of channel quality indicators.

33. The apparatus of claim 25, further comprising: means for selecting the one or more new beams for transmitting the negative acknowledgement for the downlink transmission based at least in part on the set of channel quality indicators.

34. The apparatus of claim 25, further comprising: means for determining that a timing offset between transmitting the measurement report and a timing for transmitting the negative acknowledgement via the one or more new beams of the set of candidate beams satisfies a timing threshold, where transmitting the negative acknowledgement via the one or more new beams of the set of candidate beams is based at least in part on determining that the timing offset satisfies the timing threshold.

35. The apparatus of claim 25, wherein, the means for transmitting the negative acknowledgement for the downlink transmission via the one or more new beams of the set of candidate beams comprises: means for transmitting the negative acknowledgement for the downlink transmission via the one or more new beams without receiving an indication from the base station to transmit the negative acknowledgement for the downlink transmission via the one or more new beams after determining that the downlink transmission from the base station is not received via the one or more beams.

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