WO2021227055A1

WO2021227055A1 - Ue requested ul beam refinement

Info

Publication number: WO2021227055A1
Application number: PCT/CN2020/090636
Authority: WO
Inventors: Yan Zhou; Fang Yuan; Tao Luo
Original assignee: Qualcomm Incorporated
Priority date: 2020-05-15
Filing date: 2020-05-15
Publication date: 2021-11-18

Abstract

Aspects of the disclosure relate to a user equipment (UE) requesting an uplink beam refinement of one or more uplink beams utilized for communication with a base station. The request for uplink beam refinement may include at least one beam refinement parameter. For example, the beam refinement parameter(s) may indicate one or more of a selected beam management scheme, a selected beam sweep type, a selected uplink transmission scheme for transmission of an uplink signal on the refined uplink beam(s), or an indication of an uplink signal associated with the refined beam(s). Other aspects, features, and embodiments are also claimed and described.

Description

UE REQUESTED UL BEAM REFINEMENT

TECHNICAL FIELD

The technology discussed below relates generally to wireless communication networks, and more particularly, to uplink beam selection in beam-based communication scenarios (e.g., millimeter wave beams) .

BACKGROUND

In wireless communication systems, such as those specified under standards for 5G New Radio (NR) , a base station and user equipment (UE) may utilize beamforming to compensate for high path loss and short range. Beamforming is a signal processing technique used with an antenna array module for directional signal transmission and/or reception. Each antenna in the antenna array module transmits a signal that is combined with other signals of other antennas of the same array in such a way that signals at particular angles experience constructive interference while others experience destructive interference.

The base station and the UE can select one or more beam pair links (BPLs) for communication therebetween on the downlink and/or the uplink. Each BPL includes corresponding transmit and receive beams on the base station and UE. For example, on the downlink, a BPL includes a transmit beam on the base station and a receive beam on the UE. To increase the data rate on the downlink, multiple BPLs can be used to facilitate spatial multiplexing of multiple data streams from the base station to the UE. At the UE, the different BPLs can include receive beams from the same antenna array module or different antenna array modules.

As the demand for mobile broadband access continues to increase, research and development continue to advance beamforming communication technologies, including technologies for enhancing beamforming management in particular, not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.

BRIEF SUMMARY OF SOME EXAMPLES

The following presents a summary of one or more aspects of the present disclosure, in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in a form as a prelude to the more detailed description that is presented later.

In one example, a method for wireless communication at a user equipment (UE) in a wireless communication network is disclosed. The method includes communicating with a base station using at least a first uplink beam of a plurality of uplink beams and transmitting a request for an uplink beam refinement. The request includes at least one beam refinement parameter. The method further includes performing the uplink beam refinement based on the at least one beam refinement parameter and identifying at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the base station.

Another example provides a UE in a wireless communication network including a wireless transceiver, a memory, and a processor communicatively coupled to the wireless transceiver and the memory. The processor and the memory can be configured to communicate with a base station using at least a first uplink beam of a plurality of uplink beams and transmit a request for an uplink beam refinement. The request includes at least one beam refinement parameter. The processor and the memory can further be configured to perform the uplink beam refinement based on the at least one beam refinement parameter and identify at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the base station.

Another example provides a UE in a wireless communication network. The UE can include means for communicating with a base station using at least a first uplink beam of a plurality of uplink beams and means for transmitting a request for an uplink beam refinement. The request includes at least one beam refinement parameter. The UE can further include means for performing the uplink beam refinement based on the at least one beam refinement parameter and means for identifying at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the base station.

Another example provides a non-transitory computer-readable medium including code for causing a UE to communicate with a base station using at least a first uplink beam of a plurality of uplink beams and transmit a request for an uplink beam refinement. The request includes at least one beam refinement parameter. The non-transitory computer-readable medium can further include code for causing the UE to perform the uplink beam refinement based on the at least one beam refinement parameter and identify at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the base station.

In another example, a method for wireless communication at a base station in a wireless communication network is disclosed. The method includes communicating with a user equipment (UE) using at least a first uplink beam of a plurality of uplink beams and receiving a request for an uplink beam refinement. The request includes at least one beam refinement parameter. The method further includes performing the uplink beam refinement based on the at least one beam refinement parameter and identifying at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the UE.

Another example provides a base station in a wireless communication network including a wireless transceiver, a memory, and a processor communicatively coupled to the wireless transceiver and the memory. The processor and the memory can be configured to communicate with a user equipment (UE) using at least a first uplink beam of a plurality of uplink beams and receive a request for an uplink beam refinement. The request includes at least one beam refinement parameter. The processor and the memory can further be configured to perform the uplink beam refinement based on the at least one beam refinement parameter and identify at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the UE.

Another example provides a base station in a wireless communication network. The base station can include means for communicating with a user equipment (UE) using at least a first uplink beam of a plurality of uplink beams and means for receiving a request for an uplink beam refinement. The request includes at least one beam refinement parameter. The base station can further include means for performing the uplink beam refinement based on the at least one beam refinement parameter and means for identifying at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the UE.

Another example provides a non-transitory computer-readable medium including code for causing a base station to communicate with a user equipment (UE) using at least a first uplink beam of a plurality of uplink beams and receive a request for an uplink beam refinement. The request includes at least one beam refinement parameter. The non-transitory computer-readable medium can further include code for causing the base station to perform the uplink beam refinement based on the at least one beam refinement parameter and identify at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the UE.

These and other aspects will become more fully understood upon a review of the detailed description, which follows. Other aspects, features, and embodiments will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments of in conjunction with the accompanying figures. While features may be discussed relative to certain embodiments and figures below, all embodiments can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments, such exemplary embodiments can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a wireless communication system according to some aspects.

FIG. 2 is a conceptual illustration of an example of a radio access network according to some aspects.

FIG. 3 is a diagram illustrating an example of a frame structure for use in a radio access network according to some aspects.

FIG. 4 is a block diagram illustrating a wireless communication system supporting beamforming and/or multiple-input multiple-output (MIMO) communication according to some aspects.

FIG. 5 is a diagram illustrating an example of communication between a radio access network (RAN) node and a wireless communication device using beamforming according to some aspects.

FIG. 6 is a signaling diagram illustrating an example of signaling between a UE and a base station for downlink beam management according to some aspects.

FIG. 7 is a signaling diagram illustrating an example of signaling between a UE and a base station for uplink beam management according to some aspects.

FIG. 8 is a signaling diagram illustrating an example of signaling between a UE and a base station for uplink beam refinement according to some aspects.

FIG. 9 is a signaling diagram illustrating an example of signaling between a UE and a base station for obtaining an uplink grant for requesting uplink beam refinement according to some aspects.

FIG. 10 is a signaling diagram illustrating an example of random access signaling between a UE and a base station to request uplink beam refinement according to some aspects.

FIG. 11 is a signaling diagram illustrating another example of random access signaling between a UE and a base station to request uplink beam refinement according to some aspects.

FIGs. 12A–12C are diagrams illustrating examples of beam sweep types for uplink beam refinement according to some aspects.

FIGs. 13A–13C are diagrams illustrating exemplary multiplexing of multiple selected uplink beams according to some aspects.

FIG. 14 is a diagram illustrating exemplary beam repetitions of selected uplink beams according to some aspects.

FIG. 15 is a block diagram illustrating an example of a hardware implementation for a UE employing a processing system according to some aspects.

FIG. 16 is a block diagram illustrating an example of a hardware implementation for a base station employing a processing system according to some aspects.

FIG. 17 is a flow chart of an exemplary method for requesting uplink beam refinement according to some aspects.

FIG. 18 is a flow chart of another exemplary method for requesting uplink beam refinement according to some aspects.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

The electromagnetic spectrum is often subdivided by various authors or entities into different classes, bands, channels, or the like, based on frequency/wavelength. For example, in 5G NR two initial operating bands have been identified as frequency range designations FR1 (410 MHz-7125 MHz) and FR2 (24250 MHz –52600 MHz) . Even though a portion of FR1 is greater than 6 GHz (> 6000 MHz) , FR1 is often referred to (interchangeably) as a Sub-6 GHz band in various documents and articles regarding 5G NR topics. A similar nomenclature issue sometimes occurs with regard to FR2 in various documents and articles regarding 5G NR topics. While a portion of FR2 is less than 30 GHz (< 30000 MHz) , FR2 is often referred to (interchangeably) as a millimeter wave band. However, some authors/entities tend to define wireless signals with wavelengths between 1-10 millimeters as falling within a millimeter wave band (30 GHz –300 GHz) .

With the above examples in mind, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” if used herein by way of example may represent all or part of FR1 for 5G NR. Further, unless specifically stated otherwise, it should be understood that the term “millimeter wave” as used herein by way of example may represent all or part of FR2 for 5G NR and/or all or part of a 30 GHz-300 GHz waveband. It should also be understood that the terms “sub-6 GHz” and “millimeter wave, ” are intended to represent modifications to such example frequency bands that may occur do to author/entity decisions regarding wireless communications, e.g., as presented by example herein.

It should be understood that the above examples are not necessarily intended to limit claimed subject matter. For example, unless specifically recited, claimed subject matter relating to wireless communications is not necessarily intended to be limited to any particular author/entity defined frequency band, or the like.

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

Various aspects of the disclosure relate to a user equipment (UE) requesting an uplink beam refinement of one or more uplink beams utilized for communication with a base station. The request for uplink beam refinement may include at least one beam refinement parameter. For example, the beam refinement parameter (s) may indicate one or more of a selected beam management scheme, a selected beam sweep type, a selected uplink transmission scheme for transmission of an uplink signal on the refined uplink beam (s) , or an indication of an uplink signal associated with the refined beam (s) . The indication of the uplink signal may be an uplink signal identifier of the uplink signal or a spatial identifier associated with the uplink beam utilized for transmission of the uplink signal prior to uplink beam refinement.

In some examples, the request may indicate one or more transmission parameters associated with the selected uplink transmission scheme. For example, the request may indicate one or more of a number of uplink beams to use for transmission of an uplink signal, a number of repetitions per beam, or a multiplexing scheme when multiple beams are used for transmission of the uplink signal. In some examples, the selected uplink beam management scheme may include an uplink beam management scheme or a downlink beam management scheme to utilize for refining the uplink beam (s) . The request may further indicate a beam sweep type (e.g., coarse or narrow beams or a number of beam repetitions during the uplink beam refinement) . In addition, the request may further indicate a number of reference signal resources (e.g., SRS resources or SSB/CSI-RS resources) to utilize for the selected beam sweep type.

The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. Referring now to FIG. 1, as an illustrative example without limitation, various aspects of the present disclosure are illustrated with reference to a wireless communication system 100. The wireless communication system 100 includes three interacting domains: a core network 102, a radio access network (RAN) 104, and a user equipment (UE) 106. By virtue of the wireless communication system 100, the UE 106 may be enabled to carry out data communication with an external data network 110, such as (but not limited to) the Internet.

The RAN 104 may implement any suitable wireless communication technology or technologies to provide radio access to the UE 106. As one example, the RAN 104 may operate according to 3rd Generation Partnership Project (3GPP) New Radio (NR) specifications, often referred to as 5G. As another example, the RAN 104 may operate under a hybrid of 5G NR and Evolved Universal Terrestrial Radio Access Network (eUTRAN) standards, often referred to as LTE. The 3GPP refers to this hybrid RAN as a next-generation RAN, or NG-RAN. Of course, many other examples may be utilized within the scope of the present disclosure.

As illustrated, the RAN 104 includes a plurality of base stations 108. Broadly, a base station is a network element in a radio access network responsible for radio transmission and reception in one or more cells to or from a UE. In different technologies, standards, or contexts, a base station may variously be referred to by those skilled in the art as a base transceiver station (BTS) , a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , an access point (AP) , a Node B (NB) , an eNode B (eNB) , a gNode B (gNB) , or some other suitable terminology.

The radio access network 104 is further illustrated supporting wireless communication for multiple mobile apparatuses. A mobile apparatus may be referred to as user equipment (UE) in 3GPP standards, but may also be referred to by those skilled in the art as a mobile station (MS) , a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT) , a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. A UE may be an apparatus that provides a user with access to network services.

Within the present document, a “mobile” apparatus need not necessarily have a capability to move, and may be stationary. The term mobile apparatus or mobile device broadly refers to a diverse array of devices and technologies. UEs may include a number of hardware structural components sized, shaped, and arranged to help in communication; such components can include antennas, antenna arrays, RF chains, amplifiers, one or more processors, etc. electrically coupled to each other. For example, some non-limiting examples of a mobile apparatus include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal computer (PC) , a notebook, a netbook, a smartbook, a tablet, a personal digital assistant (PDA) , and a broad array of embedded systems, e.g., corresponding to an “Internet of Things” (IoT) . A mobile apparatus may additionally be an automotive or other transportation vehicle, a remote sensor or actuator, a robot or robotics device, a satellite radio, a global positioning system (GPS) device, an object tracking device, a drone, a multi-copter, a quad-copter, a remote control device, a consumer and/or wearable device, such as eyewear, a wearable camera, a virtual reality device, a smart watch, a health or fitness tracker, a digital audio player (e.g., MP3 player) , a camera, a game console, etc. A mobile apparatus may additionally be a digital home or smart home device such as a home audio, video, and/or multimedia device, an appliance, a vending machine, intelligent lighting, a home security system, a smart meter, etc. A mobile apparatus may additionally be a smart energy device, a security device, a solar panel or solar array, a municipal infrastructure device controlling electric power (e.g., a smart grid) , lighting, water, an industrial automation and enterprise device, a logistics controller, agricultural equipment, etc. Still further, a mobile apparatus may provide for connected medicine or telemedicine support, i.e., health care at a distance. Telehealth devices may include telehealth monitoring devices and telehealth administration devices, whose communication may be given preferential treatment or prioritized access over other types of information, e.g., in terms of prioritized access for transport of critical service data, and/or relevant QoS for transport of critical service data.

Wireless communication between a RAN 104 and a UE 106 may be described as utilizing an air interface. Transmissions over the air interface from a base station (e.g., base station 108) to one or more UEs (e.g., UE 106) may be referred to as downlink (DL) transmission. In accordance with certain aspects of the present disclosure, the term downlink may refer to a point-to-multipoint transmission originating at a scheduling entity (described further below; e.g., base station 108) . Another way to describe this scheme may be to use the term broadcast channel multiplexing. Transmissions from a UE (e.g., UE 106) to a base station (e.g., base station 108) may be referred to as uplink (UL) transmissions. In accordance with further aspects of the present disclosure, the term uplink may refer to a point-to-point transmission originating at a scheduled entity (described further below; e.g., UE 106) .

In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station 108) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communication, UEs 106, which may be scheduled entities, may utilize resources allocated by the scheduling entity 108.

Base stations 108 are not the only entities that may function as scheduling entities. That is, in some examples, a UE may function as a scheduling entity, scheduling resources for one or more scheduled entities (e.g., one or more other UEs) . And as discussed more below, UEs may communicate directly with other UEs in peer-to-peer fashion and/or in relay configuration.

As illustrated in FIG. 1, a scheduling entity 108 may broadcast downlink traffic 112 to one or more scheduled entities 106. Broadly, the scheduling entity 108 is a node or device responsible for scheduling traffic in a wireless communication network, including the downlink traffic 112 and, in some examples, uplink traffic 116 from one or more scheduled entities 106 to the scheduling entity 108. On the other hand, the scheduled entity 106 is a node or device that receives downlink control information 114, including but not limited to scheduling information (e.g., a grant) , synchronization or timing information, or other control information from another entity in the wireless communication network such as the scheduling entity 108.

In addition, the uplink and/or downlink control information and/or traffic information may be time-divided into frames, subframes, slots, and/or symbols. As used herein, a symbol may refer to a unit of time that, in an orthogonal frequency division multiplexed (OFDM) waveform, carries one resource element (RE) per sub-carrier. A slot may carry 7 or 14 OFDM symbols. A subframe may refer to a duration of 1ms. Multiple subframes or slots may be grouped together to form a single frame or radio frame. Of course, these definitions are not required, and any suitable scheme for organizing waveforms may be utilized, and various time divisions of the waveform may have any suitable duration.

In general, base stations 108 may include a backhaul interface for communication with a backhaul portion 120 of the wireless communication system. The backhaul 120 may provide a link between a base station 108 and the core network 102. Further, in some examples, a backhaul network may provide interconnection between the respective base stations 108. Various types of backhaul interfaces may be employed, such as a direct physical connection, a virtual network, or the like using any suitable transport network.

The core network 102 may be a part of the wireless communication system 100, and may be independent of the radio access technology used in the RAN 104. In some examples, the core network 102 may be configured according to 5G standards (e.g., 5GC) . In other examples, the core network 102 may be configured according to a 4G evolved packet core (EPC) , or any other suitable standard or configuration.

Referring now to FIG. 2, by way of example and without limitation, a schematic illustration of a RAN 200 is provided. In some examples, the RAN 200 may be the same as the RAN 104 described above and illustrated in FIG. 1. The geographic area covered by the RAN 200 may be divided into cellular regions (cells) that can be uniquely identified by a user equipment (UE) based on an identification broadcasted from one access point or base station. FIG. 2 illustrates

macrocells

202, 204, and 206, and a small cell 208, each of which may include one or more sectors (not shown) . A sector is a sub-area of a cell. All sectors within one cell are served by the same base station. A radio link within a sector can be identified by a single logical identification belonging to that sector. In a cell that is divided into sectors, the multiple sectors within a cell can be formed by groups of antennas with each antenna responsible for communication with UEs in a portion of the cell.

Various base station arrangements can be utilized. For example, in FIG. 2, two base stations 210 and 212 are shown in

cells

202 and 204; and a third base station 214 is shown controlling a remote radio head (RRH) 216 in cell 206. That is, a base station can have an integrated antenna or can be connected to an antenna or RRH by feeder cables. In the illustrated example, the

cells

202, 204, and 206 may be referred to as macrocells, as the

base stations

210, 212, and 214 support cells having a large size. Further, a base station 218 is shown in the small cell 208 (e.g., a microcell, picocell, femtocell, home base station, home Node B, home eNode B, etc. ) which may overlap with one or more macrocells. In this example, the cell 208 may be referred to as a small cell, as the base station 218 supports a cell having a relatively small size. Cell sizing can be done according to system design as well as component constraints.

It is to be understood that the radio access network 200 may include any number of wireless base stations and cells. Further, a relay node may be deployed to extend the size or coverage area of a given cell. The

base stations

210, 212, 214, 218 provide wireless access points to a core network for any number of mobile apparatuses. In some examples, the

base stations

210, 212, 214, and/or 218 may be the same as the base station/scheduling entity 108 described above and illustrated in FIG. 1.

Within the RAN 200, the cells may include UEs that may be in communication with one or more sectors of each cell. Further, each

base station

210, 212, 214, and 218 may be configured to provide an access point to a core network 102 (see FIG. 1) for all the UEs in the respective cells. For example,

UEs

222 and 224 may be in communication with base station 210;

UEs

226 and 228 may be in communication with base station 212;

UEs

230 and 232 may be in communication with base station 214 by way of RRH 216; and UE 234 may be in communication with base station 218. In some examples, the

UEs

222, 224, 226, 228, 230, 232, 234, 238, 240, and/or 242 may be the same as the UE/scheduled entity 106 described above and illustrated in FIG. 1.

In some examples, an unmanned aerial vehicle (UAV) 220, which may be a drone or quadcopter, can be a mobile network node and may be configured to function as a UE. For example, the UAV 220 may operate within cell 202 by communicating with base station 210.

In a further aspect of the RAN 200, sidelink signals may be used between UEs without necessarily relying on scheduling or control information from a base station. For example, two or more UEs (e.g., UEs 226 and 228) may communicate with each other using peer to peer (P2P) or sidelink signals 227 without relaying that communication through a base station (e.g., base station 212) . In a further example, UE 238 is illustrated communicating with

UEs

240 and 242. Here, the UE 238 may function as a scheduling entity or a primary sidelink device, and

UEs

240 and 242 may each function as a scheduled entity or a non-primary (e.g., secondary) sidelink device. In still another example, a UE may function as a scheduling entity or scheduled entity in a device-to-device (D2D) , peer-to-peer (P2P) , vehicle-to-vehicle (V2V) network, vehicle- to-everything (V2X) and/or in a mesh network. In a mesh network example,

UEs

240 and 242 may optionally communicate directly with one another in addition to communicating with the scheduling entity 238. Thus, in a wireless communication system with scheduled access to time–frequency resources and having a cellular configuration, a P2P configuration, or a mesh configuration, a scheduling entity and one or more scheduled entities may communicate utilizing the scheduled resources. In some examples, the sidelink signals 227 include sidelink traffic and sidelink control.

The air interface in the radio access network 200 may utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of the various devices. For example, 5G NR specifications provide multiple access for UL transmissions from

UEs

222 and 224 to base station 210, and for multiplexing for DL transmissions from base station 210 to one or

more UEs

222 and 224, utilizing orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) . In addition, for UL transmissions, 5G NR specifications provide support for discrete Fourier transform-spread-OFDM (DFT-s-OFDM) with a CP (also referred to as single-carrier FDMA (SC-FDMA) ) . However, within the scope of the present disclosure, multiplexing and multiple access are not limited to the above schemes, and may be provided utilizing time division multiple access (TDMA) , code division multiple access (CDMA) , frequency division multiple access (FDMA) , sparse code multiple access (SCMA) , resource spread multiple access (RSMA) , or other suitable multiple access schemes. Further, multiplexing DL transmissions from the base station 210 to UEs 222 and 224 may be provided utilizing time division multiplexing (TDM) , code division multiplexing (CDM) , frequency division multiplexing (FDM) , orthogonal frequency division multiplexing (OFDM) , sparse code multiplexing (SCM) , or other suitable multiplexing schemes.

The air interface in the radio access network 200 may further utilize one or more duplexing algorithms. Duplex refers to a point-to-point communication link where both endpoints can communicate with one another in both directions. Full duplex means both endpoints can simultaneously communicate with one another. Half duplex means only one endpoint can send information to the other at a time. In a wireless link, a full duplex channel generally relies on physical isolation of a transmitter and receiver, and suitable interference cancellation technologies. Full duplex emulation is frequently implemented for wireless links by utilizing frequency division duplex (FDD) or time division duplex (TDD) . In FDD, transmissions in different directions operate at different carrier frequencies. In TDD, transmissions in different directions on a given channel are separated from one another using time division multiplexing. That is, at some times the channel is dedicated for transmissions in one direction, while at other times the channel is dedicated for transmissions in the other direction, where the direction may change very rapidly, e.g., several times per slot.

Various aspects of the present disclosure will be described with reference to an OFDM waveform, schematically illustrated in FIG. 3. It should be understood by those of ordinary skill in the art that the various aspects of the present disclosure may be applied to an SC-FDMA waveform in substantially the same way as described herein below. That is, while some examples of the present disclosure may focus on an OFDM link for clarity, it should be understood that the same principles may be applied as well to SC-FDMA waveforms.

Referring now to FIG. 3, an expanded view of an exemplary DL subframe 302 is illustrated, showing an OFDM resource grid. However, as those skilled in the art will readily appreciate, the PHY transmission structure for any particular application may vary from the example described here, depending on any number of factors. Here, time is in the horizontal direction with units of OFDM symbols; and frequency is in the vertical direction with units of subcarriers.

The resource grid 304 may be used to schematically represent time–frequency resources for a given antenna port. That is, in a multiple-input-multiple-output (MIMO) implementation with multiple antenna ports available, a corresponding multiple number of resource grids 304 may be available for communication. The resource grid 304 is divided into multiple resource elements (REs) 306. An RE, which is 1 subcarrier × 1 symbol, is the smallest discrete part of the time–frequency grid, and contains a single complex value representing data from a physical channel or signal. Depending on the modulation utilized in a particular implementation, each RE may represent one or more bits of information. In some examples, a block of REs may be referred to as a physical resource block (PRB) or a resource block (RB) 308, which contains any suitable number of consecutive subcarriers in the frequency domain. In one example, an RB may include 12 subcarriers, a number independent of the numerology used. In some examples, depending on the numerology, an RB may include any suitable number of consecutive OFDM symbols in the time domain. Within the present disclosure, it is assumed that a single RB such as the RB 308 entirely corresponds to a single direction of communication (either transmission or reception for a given device) .

Scheduling of UEs (e.g., scheduled entities) for downlink or uplink transmissions typically involves scheduling one or more resource elements 306 within one or more sub-bands. Thus, a UE generally utilizes only a subset of the resource grid 304. In some examples, an RB may be the smallest unit of resources that can be allocated to a UE. Thus, the more RBs scheduled for a UE, and the higher the modulation scheme chosen for the air interface, the higher the data rate for the UE.

In this illustration, the RB 308 is shown as occupying less than the entire bandwidth of the subframe 302, with some subcarriers illustrated above and below the RB 308. In a given implementation, the subframe 302 may have a bandwidth corresponding to any number of one or more RBs 308. Further, in this illustration, the RB 308 is shown as occupying less than the entire duration of the subframe 302, although this is merely one possible example.

Each 1 ms subframe 302 may consist of one or multiple adjacent slots. In the example shown in FIG. 3, one subframe 302 includes four slots 310, as an illustrative example. In some examples, a slot may be defined according to a specified number of OFDM symbols with a given cyclic prefix (CP) length. For example, a slot may include 7 or 14 OFDM symbols with a nominal CP. Additional examples may include mini-slots, sometimes referred to as shortened transmission time intervals (TTIs) , having a shorter duration (e.g., one to three OFDM symbols) . These mini-slots or shortened transmission time intervals (TTIs) may in some cases be transmitted occupying resources scheduled for ongoing slot transmissions for the same or for different UEs. Any number of resource blocks may be utilized within a subframe or slot.

An expanded view of one of the slots 310 illustrates the slot 310 including a control region 312 and a data region 314. In general, the control region 312 may carry control channels, and the data region 314 may carry data channels. Of course, a slot may contain all DL, all UL, or at least one DL portion and at least one UL portion. The structure illustrated in FIG. 3 is merely exemplary in nature, and different slot structures may be utilized, and may include one or more of each of the control region (s) and data region (s) .

Although not illustrated in FIG. 3, the various REs 306 within a RB 308 may be scheduled to carry one or more physical channels, including control channels, shared channels, data channels, etc. Other REs 306 within the RB 308 may also carry pilots or reference signals, including but not limited to a demodulation reference signal (DMRS) , a control reference signal (CRS) , or a sounding reference signal (SRS) . These pilots or reference signals may provide for a receiving device to perform channel estimation of the corresponding channel, which may enable coherent demodulation/detection of the control and/or data channels within the RB 308.

In a DL transmission, the transmitting device (e.g., the scheduling entity) may allocate one or more REs 306 (e.g., within a control region 312) to carry DL control information including one or more DL control channels, such as a PBCH and/or a physical downlink control channel (PDCCH) , etc., to one or more scheduled entities. The PDCCH carries downlink control information (DCI) including but not limited to power control commands, scheduling information, a grant, and/or an assignment of REs for DL and UL transmissions. The transmitting device may further allocate one or more REs 306 to carry other DL signals, such as a DMRS; a phase-tracking reference signal (PT-RS) ; a channel state information –reference signal (CSI-RS) ; a primary synchronization signal (PSS) ; and a secondary synchronization signal (SSS) . A UE may utilize the PSS and SSS to achieve radio frame, subframe, slot, and symbol synchronization in the time domain, identify the center of the channel (system) bandwidth in the frequency domain, and identify the physical cell identity (PCI) of the cell.

The synchronization signals PSS and SSS, and in some examples, the PBCH and a PBCH DMRS, may be transmitted in a synchronization signal block (SSB) that includes 4 consecutive OFDM symbols, numbered via a time index in increasing order from 0 to 4. In the frequency domain, the SSB may extend over 240 contiguous subcarriers, with the subcarriers being numbered via a frequency index in increasing order from 0 to 249. Of course, the present disclosure is not limited to this specific SSB configuration. Other non-limiting examples may utilize greater or fewer than two synchronization signals; may include one or more supplemental channels in addition to the PBCH; may omit a PBCH; and/or may utilize a different number of symbols/frequencies and/or nonconsecutive symbols/frequencies for an SSB, within the scope of the present disclosure.

The PBCH may further include a master information block (MIB) that includes various system information, along with parameters for decoding a system information block (SIB) . The SIB may be, for example, a SystemInformationType 1 (SIB1) that may include various additional system information. Examples of system information transmitted in the MIB may include, but are not limited to, a subcarrier spacing, system frame number, a configuration of a PDCCH control resource set (CORESET) (e.g., PDCCH CORESET0) , and a search space for SIB1. Examples of additional system information transmitted in the SIB1 may include, but are not limited to, a random access search space, downlink configuration information, and uplink configuration information. The MIB and SIB1 together provide the minimum system information (SI) for initial access.

In an UL transmission, the transmitting device (e.g., the scheduled entity 106) may utilize one or more REs 306 to carry UL control information including one or more UL control channels, such as a physical uplink control channel (PUCCH) , to the scheduling entity. UL control information may include a variety of packet types and categories, including pilots, reference signals, and information configured to enable or assist in decoding uplink data transmissions. For example, the UL control information may include a DMRS or SRS. In some examples, the control information may include a scheduling request (SR) , i.e., request for the scheduling entity to schedule uplink transmissions. Here, in response to the SR transmitted on the control channel, the scheduling entity may transmit downlink control information that may schedule resources for uplink packet transmissions. UL control information may also include hybrid automatic repeat request (HARQ) feedback, channel state feedback (CSF) , or any other suitable UL control information.

In addition to control information, one or more REs 306 (e.g., within the data region 314) may be allocated for user data traffic. Such traffic may be carried on one or more traffic channels, such as, for a DL transmission, a physical downlink shared channel (PDSCH) ; or for an UL transmission, a physical uplink shared channel (PUSCH) . In some examples, one or more REs 306 within the data region 314 may be configured to carry SIBs (e.g., SIB1) , carrying information that may enable access to a given cell.

These physical channels described above are generally multiplexed and mapped to transport channels for handling at the medium access control (MAC) layer. Transport channels carry blocks of information called transport blocks (TB) . The transport block size (TBS) , which may correspond to a number of bits of information, may be a controlled parameter, based on the modulation and coding scheme (MCS) and the number of RBs in a given transmission.

The channels or carriers described above in connection with FIGs. 1–3 are not necessarily all of the channels or carriers that may be utilized between a scheduling entity and scheduled entities, and those of ordinary skill in the art will recognize that other channels or carriers may be utilized in addition to those illustrated, such as other traffic, control, and feedback channels.

In some aspects of the disclosure, the scheduling entity and/or scheduled entity may be configured for beamforming and/or multiple-input multiple-output (MIMO) technology. FIG. 4 illustrates an example of a wireless communication system 400 supporting beamforming and/or MIMO. In a MIMO system, a transmitter 402 includes multiple transmit antennas 404 (e.g., N transmit antennas) and a receiver 406 includes multiple receive antennas 408 (e.g., M receive antennas) . Thus, there are N × M signal paths 410 from the transmit antennas 404 to the receive antennas 408. Each of the transmitter 402 and the receiver 406 may be implemented, for example, within a scheduling entity, a scheduled entity, or any other suitable wireless communication device.

The use of such multiple antenna technology enables the wireless communication system to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing may be used to transmit different streams of data, also referred to as layers, simultaneously on the same time-frequency resource. The data streams may be transmitted to a single UE to increase the data rate or to multiple UEs to increase the overall system capacity, the latter being referred to as multi-user MIMO (MU-MIMO) . This is achieved by spatially precoding each data stream (i.e., multiplying the data streams with different weighting and phase shifting) and then transmitting each spatially precoded stream through multiple transmit antennas on the downlink. The spatially precoded data streams arrive at the UE (s) with different spatial signatures, which enables each of the UE (s) to recover the one or more data streams destined for that UE. On the uplink, each UE transmits a spatially precoded data stream, which enables the base station to identify the source of each spatially precoded data stream.

The number of data streams or layers corresponds to the rank of the transmission. In general, the rank of the MIMO system 400 is limited by the number of transmit or receive

antennas

404 or 408, whichever is lower. In addition, the channel conditions at the UE, as well as other considerations, such as the available resources at the base station, may also affect the transmission rank. For example, the rank (and therefore, the number of data streams) assigned to a particular UE on the downlink may be determined based on the rank indicator (RI) transmitted from the UE to the base station. The RI may be determined based on the antenna configuration (e.g., the number of transmit and receive antennas) and a measured signal-to-interference-and-noise ratio (SINR) on each of the receive antennas. The RI may indicate, for example, the number of layers that may be supported under the current channel conditions. The base station may use the RI, along with resource information (e.g., the available resources and amount of data to be scheduled for the UE) , to assign a transmission rank to the UE.

In one example, as shown in FIG. 4, a rank-2 spatial multiplexing transmission on a 2x2 MIMO antenna configuration will transmit one data stream from each transmit antenna 404. Each data stream reaches each receive antenna 408 along a different signal path 410. The receiver 406 may then reconstruct the data streams using the received signals from each receive antenna 408.

Beamforming is a signal processing technique that may be used at the transmitter 402 or receiver 406 to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitter 402 and the receiver 406. Beamforming may be achieved by combining the signals communicated via antennas 404 or 408 (e.g., antenna elements of an antenna array module) such that some of the signals experience constructive interference while others experience destructive interference. To create the desired constructive/destructive interference, the transmitter 402 or receiver 406 may apply amplitude and/or phase offsets to signals transmitted or received from each of the

antennas

404 or 408 associated with the transmitter 402 or receiver 406.

In 5G New Radio (NR) systems, particularly for above 6 GHz or mmWave systems, beamformed signals may be utilized for most downlink channels, including the physical downlink control channel (PDCCH) and physical downlink shared channel (PDSCH) . In addition, broadcast control information, such as the SSB, slot format indicator (SFI) , and paging information, may be transmitted in a beam-sweeping manner to enable all scheduled entities (UEs) in the coverage area of a transmission and reception point (TRP) (e.g., a gNB) to receive the broadcast control information. In addition, for UEs configured with beamforming antenna arrays, beamformed signals may also be utilized for uplink channels, including the physical uplink control channel (PUCCH) and physical uplink shared channel (PUSCH) . However, it should be understood that beamformed signals may also be utilized by enhanced mobile broadband (eMBB) gNBs for sub-6 GHz systems.

A base station (e.g., gNB) may generally be capable of communicating with UEs using transmit beams (e.g., downlink transmit beams) of varying beam widths. For example, a base station may be configured to utilize a wider beam when communicating with a UE that is in motion and a narrower beam when communicating with a UE that is stationary. The UE may further be configured to utilize one or more downlink receive beams to receive signals from the base station. In some examples, to select one or more downlink transmit beams and one or more downlink receive beams for communication with a UE, the base station may transmit a reference signal, such as an SSB or CSI-RS, on each of a plurality of downlink transmit beams in a beam-sweeping manner. The UE may measure the reference signal received power (RSRP) on each of the downlink transmit beams using one or more downlink receive beams on the UE and transmit a beam measurement report to the base station indicating the RSRP of each of the measured downlink transmit beams. The base station may then select one or more serving downlink beams (e.g., downlink transmit beams and downlink receive beams) for communication with the UE based on the beam measurement report. The resulting selected downlink transmit beam and downlink receive beam may form a downlink beam pair link. In other examples, when the channel is reciprocal, the base station may derive the particular downlink beam (s) to communicate with the UE based on uplink measurements of one or more uplink reference signals, such as sounding reference signals (SRSs) .

Similarly, uplink beams (e.g., uplink transmit beam (s) at the UE and uplink receive beam (s) at the base station) may be selected by measuring the RSRP of received uplink reference signals (e.g., SRSs) or downlink reference signals (e.g., SSBs or CSI-RSs) during an uplink or downlink beam sweep. For example, the base station may determine the uplink beams either by uplink beam management via a SRS beam sweep with measurement at the base station or by downlink beam management via an SSB/CSI-RS beam sweep with measurement at the UE. The selected uplink beam may be indicated by a selected SRS resource (e.g., time–frequency resources utilized for the transmission of a SRS) when implementing uplink beam management or a selected SSB/CSI-RS resource when implementing downlink beam management. For example, the selected SSB/CSI-RS resource can have a spatial relation to the selected uplink transmit beam (e.g., the uplink transmit beam utilized for the PUCCH, SRS, and/or PUSCH) . The resulting selected uplink transmit beam and uplink receive beam may form an uplink beam pair link.

FIG. 5 is a diagram illustrating communication between a base station 504 and a UE 502 using beamformed signals according to some aspects. The base station 504 may be any of the base stations (e.g., gNBs) or scheduling entities illustrated in FIGs. 1 and/or 2, and the UE 502 may be any of the UEs or scheduled entities illustrated in FIGs. 1 and/or 2.

In the example shown in FIG. 5, the base station 504 is configured to generate a plurality of beams 506a–506h, each associated with a different beam direction. In addition, the UE 502 is configured to generate a plurality of beams 508a–508e, each associated with a different beam direction. The base station 504 and UE 502 may select one or more beams 506a–506h on the base station 504 and one or more beams 508a–508e on the UE 502 for communication of uplink and downlink signals therebetween using a downlink beam management scheme and/or an uplink beam management scheme.

In an example of a downlink beam management scheme for selection of downlink beams, the base station 504 may be configured to sweep or transmit on each of a plurality of downlink transmit beams 506a–506h during one or more synchronization slots. For example, the base station 504 may transmit a reference signal, such as an SSB or CSI-RS, on each beam in the different beam directions during the synchronization slot. Transmission of the beam reference signals may occur periodically (e.g., as configured via radio resource control (RRC) signaling by the gNB) , semi-persistently (e.g., as configured via RRC signaling and activated/deactivated via medium access control –control element (MAC-CE) signaling by the gNB) , or aperiodically (e.g., as triggered by the gNB via downlink control information (DCI) ) . It should be noted that while some beams are illustrated as adjacent to one another, such an arrangement may be different in different aspects. For example, downlink transmit beams 506a–506h transmitted during a same symbol may not be adjacent to one another. In some examples, the base station 504 may transmit more or less beams distributed in all directions (e.g., 360 degrees) .

In addition, the UE 502 is configured to receive the downlink beam reference signals on a plurality of downlink receive beams 508a–508e. In some examples, the UE 502 searches for and identifies each of the downlink transmit beams 506a–506h based on the beam reference signals. The UE 502 then performs beam measurements (e.g., RSRP, SINR, RSRQ, etc. ) on the beam reference signals on each of the downlink receive beams 508a–508e to determine the respective beam quality of each of the downlink transmit beams 506a–506h as measured on each of the downlink receive beams 508a–508e.

The UE 502 can generate and transmit a beam measurement report, including the respective beam index and beam measurement of each downlink transmit beam 506a–506h on each downlink receive beam 508a–508e to the base station 504. The base station 504 may then select one or more downlink transmit beams on which to transmit unicast downlink control information and/or user data traffic to the UE 502. In some examples, the selected downlink transmit beam (s) have the highest gain from the beam measurement report. In some examples, the UE 502 can further identify the downlink transmit beams selected by the base station from the beam measurements. Transmission of the beam measurement report may occur periodically (e.g., as configured via RRC signaling by the gNB) , semi-persistently (e.g., as configured via RRC signaling and activated/deactivated via MAC-CE signaling by the gNB) , or aperiodically (e.g., as triggered by the gNB via DCI) .

The base station 504 or the UE 502 may further select a corresponding downlink receive beam on the UE 502 for each selected serving downlink transmit beam to form a respective downlink beam pair link (BPL) for each selected serving downlink transmit beam. For example, the UE 502 can utilize the beam measurements to select the corresponding downlink receive beam for each serving downlink transmit beam. In some examples, the selected downlink receive beam to pair with a particular downlink transmit beam may have the highest gain for that particular downlink transmit beam.

In one example, a single downlink transmit beam (e.g., beam 506d) on the base station 504 and a single downlink receive beam (e.g., beam 508c) on the UE may form a single downlink BPL used for communication between the base station 504 and the UE 502. In another example, multiple downlink transmit beams (e.g.,

beams

506c, 506d, and 506e) on the base station 504 and a single downlink receive beam (e.g., beam 508c) on the UE 502 may form respective downlink BPLs used for communication between the base station 504 and the UE 502. In another example, multiple downlink transmit beams (e.g.,

beams

506c, 506d, and 506e) on the base station 504 and multiple downlink receive beams (e.g., beams 508c and 508d) on the UE 502 may form multiple downlink BPLs used for communication between the base station 504 and the UE 502. In this example, a first downlink BPL may include downlink transmit beam 506c and downlink receive beam 508c, a second downlink BPL may include downlink transmit beam 508d and downlink receive beam 508c, and a third downlink BPL may include downlink transmit beam 508e and downlink receive beam 508d.

When the channel is reciprocal, the above-described downlink beam management scheme may also be used to select one or more uplink BPLs for uplink communication from the UE 502 to the base station 504. For example, the downlink BPL formed of

beams

506d and 508e may also serve as an uplink BPL. Here, beam 508c is utilized as an uplink transmit beam, while beam 506d is utilized as an uplink receive beam.

In an example of an uplink beam management scheme, the UE 502 may be configured to sweep or transmit on each of a plurality of uplink transmit beams 508a–508e. For example, the UE 502 may transmit a SRS on each beam in the different beam directions. In addition, the base station 504 may be configured to receive the uplink beam reference signals on a plurality of uplink receive beams 506a–506h. In some examples, the base station 504 searches for and identifies each of the uplink transmit beams 508a–508e based on the beam reference signals. The base station 504 then performs beam measurements (e.g., RSRP, SINR, RSRQ, etc. ) on the beam reference signals on each of the uplink receive beams 506a–506h to determine the respective beam quality of each of the uplink transmit beams 508a–508e as measured on each of the uplink receive beams 506a–506h.

The base station 504 may then select one or more uplink transmit beams on which the UE 502 will transmit unicast downlink control information and/or user data traffic to the base station 504. In some examples, the selected uplink transmit beam (s) have the highest gain. The base station 504 may further select a corresponding uplink receive beam on the base station 504 for each selected serving uplink transmit beam to form a respective uplink beam pair link (BPL) for each selected serving uplink transmit beam. For example, the base station 504 can utilize the beam measurements to select the corresponding uplink receive beam for each serving uplink transmit beam. In some examples, the selected uplink receive beam to pair with a particular uplink transmit beam may have the highest gain for that particular uplink transmit beam.

The base station 504 may then notify the UE 502 of the selected uplink transmit beams. For example, the base station 504 may provide the SRS resource identifiers (IDs) identifying the SRSs transmitted on the selected uplink transmit beams. In some examples, the base station 504 may apply each selected uplink transmit beam (and corresponding uplink receive beam) to an uplink signal (e.g., PUCCH, PUSCH, SRS, etc. ) and transmit the respective SRS resource IDs associated with the selected uplink transmit beams applied to each uplink signal to the UE 502. When the channel is reciprocal, the above-described uplink beam management scheme may also be used to select one or more downlink BPLs for downlink communication from the base station 504 to the UE 502. For example, the uplink BPLs may also be utilized as downlink BPLs.

FIG. 6 illustrates an example of signaling between a UE 602 and a base station 604 for downlink beam management according to some aspects. The UE 602 may correspond to any of the UEs or scheduled entities shown in FIGs. 1, 2, 4, and/or 5. In addition, the base station 604 may correspond to any of the base stations or scheduling entities shown in FIG. s1, 2, 4, and/or 5.

At 606, the base station 604 performs a beam sweep to transmit a reference signal (e.g., an SSB or CSI-RS) on each of a plurality of downlink transmit beams to the UE 602. At 608, the UE 602 identifies and measures the RSRP or other suitable beam measurement of a respective beam reference signal on each downlink receive beam of the UE for each downlink transmit beam received by the UE. In addition, at 610, the UE 602 transmits a beam measurement report, including the beam measurements, to the base station 604. At 612, the base station 604 may then select one or more serving downlink transmit beams on which to transmit unicast downlink control information and/or user data traffic to the UE 602. In some examples, the selected serving downlink transmit beam (s) have the highest gain from the beam measurement report.

At 614, the UE 602 forms downlink BPLs between the serving downlink transmit beams and serving downlink receive beams. In some examples, the UE 602 may select a corresponding serving downlink receive beam for each selected serving downlink transmit beam to form the downlink BPLs. For example, the UE 602 can identify the serving downlink transmit beams (e.g., the downlink transmit beams with the highest gain, where the number of downlink transmit beams is known based on, for example, UE capabilities) . The UE 602 can then select the corresponding downlink receive beam for each serving downlink transmit beam based on the beam measurements. In some examples, the selected downlink receive beam to pair with a particular downlink transmit beam may have the highest gain for that particular downlink transmit beam.

FIG. 7 illustrates an example of signaling between a UE 702 and a base station 704 for uplink beam management according to some aspects. The UE 702 may correspond to any of the UEs or scheduled entities shown in FIGs. 1, 2, 4, and/or 5. In addition, the base station 704 may correspond to any of the base stations or scheduling entities shown in FIG. s1, 2, 4, and/or 5.

At 706, the UE 702 performs a beam sweep to transmit a reference signal (e.g., a SRS) on each of a plurality of uplink transmit beams to the base station 704. At 708, the base station 704 identifies and measures the RSRP or other suitable beam measurement of a respective beam reference signal on each uplink receive beam of the base station for each uplink transmit beam received by the base station. At 710, the base station 704 may then select one or more serving uplink transmit beams on which the UE 702 will transmit unicast downlink control information and/or user data traffic to the base station 704. In some examples, the selected serving uplink transmit beam (s) have the highest gain from the beam measurement report.

At 712, the base station 704 forms uplink BPLs between the serving uplink transmit beams and serving uplink receive beams. In some examples, the base station 704 may select a corresponding serving uplink receive beam for each selected serving uplink transmit beam to form the uplink BPLs. For example, the base station 704 can select the corresponding uplink receive beam for each serving uplink transmit beam based on the beam measurements. In some examples, the selected uplink receive beam to pair with a particular uplink transmit beam may have the highest gain for that particular uplink transmit beam. At 714, the base station 704 notifies the UE 702 of the selected uplink transmit beams. For example, the base station 704 may provide the SRS resource ID associated with each selected serving uplink transmit beam. The base station 704 may further indicate the selected uplink transmit beam (s) applied to each uplink signal (e.g., PUCCH, PUSCH, SRS, etc. ) .

In some examples, the selected uplink BPL (s) may become degraded due to movement of the UE 702, rotation of the UE 702, or detection of a maximum permissible exposure (MPE) limit violation at the UE 702. In some cases, the base station 704 may not be aware of the degradation of the uplink BPL (s) .

Therefore, in various aspects of the disclosure, the UE 702 can transmit a request for an uplink beam refinement to the base station 704 to update (e.g., refine) the uplink beam (s) . For example, the uplink beam refinement may refine the uplink transmit beam and/or uplink receive beam of one or more uplink BPL (s) . In addition, the request may further indicate one or more transmission parameters associated with uplink signals transmitted on the refined uplink beam (s) . For example, the request may indicate one or more of a number of uplink beams to use for transmission of an uplink signal, a number of repetitions per beam, or a multiplexing scheme when multiple beams are used for transmission of the uplink signal. The request may further indicate an uplink signal (e.g., PUSCH, PUCCH, SRS, or physical random access channel (PRACH) ) to apply to the refined uplink beam (s) . For example, the request may indicate that a refined uplink beam is one or more of a PUSCH, PUCCH, SRS, or PRACH uplink beam (e.g., the refined uplink beam is utilized for transmission of a PUSCH, PUCCH, SRS, and/or PRACH) .

In some examples, the uplink beam refinement requested by the UE 702 may utilize an uplink beam management scheme or a downlink beam management scheme to refine the uplink beam (s) . The request may further indicate a beam sweep type (e.g., coarse or narrow beams or a number of beam repetitions during the uplink beam refinement) . In addition, the request may further indicate a number of reference signal resources (e.g., SRS resources or SSB/CSI-RS resources) to utilize for the selected beam sweep type.

FIG. 8 illustrates an example of signaling between a UE 802 and a base station 804 for uplink beam refinement according to some aspects. The UE 802 may correspond to any of the UEs or scheduled entities shown in FIGs. 1, 2, 4, and/or 5. In addition, the base station 804 may correspond to any of the base stations or scheduling entities shown in FIG. s1, 2, 4, and/or 5.

At 806, the UE 802 may communicate with the base station 804 using at least a first uplink beam. The first uplink beam may correspond, for example, to an uplink transmit beam of the UE 802. The uplink transmit beam may form an uplink beam pair link (BPL) with an uplink receive beam of the base station 804 for the transmission of one or more uplink signals, such as a PUCCH, PUSCH, SRS, or PRACH. In some examples, the UE 802 and base station 804 may communicate using two or more uplink BPLs.

At 808, the UE 802 may determine that uplink beam refinement may be needed to refine the uplink BPL (s) . For example, the UE 802 may determine that the uplink BPL has degraded due to UE movement, UE rotation, or an MPE limit violation. The uplink BPL (s) may be refined, for example, by selecting at least one second uplink beam for uplink communication. In some examples, the selected second uplink beam (s) may include one or more new (different) uplink transmit beams, each of which may form a respective BPL with a corresponding uplink receive beam, which may be the same or different uplink receive beam (s) . In other examples, the selected second uplink beam (s) may include the same uplink transmit beam (s) (e.g., the first uplink transmit beam) , but the first uplink transmit beam may form an uplink BPL with a different uplink receive beam.

At 810, the UE 802 may transmit a request for the uplink beam refinement to the base station 804. In some examples, the request may be transmitted within a medium access control (MAC) control element (MAC-CE) carried in a PUSCH. For example, the UE 802 may utilize an existing (known) uplink grant for the PUSCH to transmit the MAC-CE. As another example, the UE 802 may transmit a scheduling request for an uplink grant for the PUSCH to transmit the MAC-CE. In other examples, the request may be transmitted within uplink control information (UCI) in a PUCCH or a PUSCH. In still other examples, the request may be transmitted within a random access message during a random access procedure. For example, the random access message may include a RACH preamble or a PUSCH payload of the random access message. The PUSCH payload of the random access message may include a MAC-CE containing the request. In still other examples, the request may be transmitted within an uplink radio resource control (RRC) message.

The request may include at least one beam refinement parameter. In some examples, the UE 802 may be configured to select a beam management scheme to utilize for the uplink beam refinement. For example, the selected beam management scheme may be an uplink beam management scheme or a downlink beam management scheme. In this example, the at least one beam refinement parameter may include an indication of the selected beam management scheme.

For example, when the selected beam management scheme is the uplink beam management scheme, the UE 802 may further select a SRS beam sweep type. The selected SRS beam sweep type may include a full range SRS beam sweep, a local SRS beam sweep, or a SRS beam repetition. For the full range SRS beam sweep, the UE 802 may perform a SRS beam sweep of all possible candidate beams. The candidate beams in the full range SRS beam sweep may be at least at the coarse level. For example, the full range SRS beam sweep may sweep at least a plurality of coarse (e.g., wider) beams. For the local SRS beam sweep, the UE 802 may perform a SRS beam sweep of a plurality of narrow beams within a selected coarse beam. For the SRS beam repetition, the UE 802 may repeat transmission of a selected narrow beam within the plurality of narrow beams a number of times (e.g., two or more) for the base station 804 to refine the uplink receive beam. In this example, the at least one beam refinement parameter may further include an indication of the selected SRS beam sweep type. In addition, the at least one beam refinement parameter may further include a number of SRS resources to utilize for the selected SRS beam sweep type. For example, the number of SRS resources may indicate the number of repetitions that the SRS is transmitted using the same or different beams.

As another example, when the selected beam management scheme is the downlink beam management scheme, the UE 802 may further select a downlink (DL) reference signal (RS) beam sweep type. Here, the DL RS may include an SSB or a CSI-RS. The selected DL RS beam sweep type may include a full range DL RS beam sweep, a local DL RS beam sweep, or a DL RS beam repetition. For the full range DL RS beam sweep, the base station 804 may perform a DL RS beam sweep of all possible candidate beams. The candidate beams in the full range DL RS beam sweep map be at least at the coarse level. For example, the full range DL RS beam sweep may sweep at least a plurality of coarse (e.g., wider) beams (e.g., SSB beams) . For the local DL RS beam sweep, the base station 804 may perform a DL RS beam sweep of a plurality of narrow beams (e.g., CSI-RS beams) within a selected coarse beam. For the DL RS beam repetition, the base station 804 may repeat transmission of a selected narrow beam within the plurality of narrow beams a number of times (e.g., two or more) for the UE 802 to refine the downlink receive beam. The refined downlink receive beam may further be utilized by the UE 802 as the selected uplink transmit beam. In this example, the at least one beam refinement parameter may further include an indication of the selected DL RS beam sweep type. In addition, the at least one beam refinement parameter may further include a number of DL RS resources to utilize for the selected DL RS beam sweep type. For example, the number of DL RS resources may indicate the number of repetitions that the DL RS is transmitted using the same or different beams.

In some examples, the UE 802 may further be configured to select an uplink transmission scheme to utilize for the at least one selected uplink beam selected during the uplink beam refinement. For example, the selected uplink transmission scheme may be used to transmit an uplink signal (e.g., PUSCH, PUCCH, SRS, or PRACH) on the selected uplink beam (s) . In this example, the at least one beam refinement parameter may include at least one uplink transmission parameter associated with the uplink transmission scheme. For example, the at least one uplink transmission parameter may indicate a number of uplink transmit beams to utilize for transmission of the uplink signal. The at least one uplink transmission parameter may further indicate a multiplexing scheme when the number of uplink transmit beams is greater than one. For example, the uplink transmit beams for the uplink signal may be frequency division multiplexed, time division multiplexed, or spatial division multiplexed. As another example, the at least one uplink transmission parameter may further indicate a number of repetitions of each of the uplink transmit beams for transmission of the uplink reference signal.

In some examples, the UE 802 may select the uplink transmission scheme and corresponding uplink transmission parameter (s) based on one or more of an amount of buffered uplink traffic, quality of service (QoS) requirements for the uplink traffic, or the battery life of the UE 802. For example, the UE may select time division multiplexing (TDM) or frequency division multiplexing (FDM) of multiple uplink transmit beams for transmission of the uplink signal for delay sensitive traffic, such as ultra-reliable low-latency communication (URLLC) traffic. As another example, the UE 802 may select spatial division multiplexing (SDM) of multiple uplink transmit beams for transmission of the uplink signal for high data rate traffic, such as enhanced mobile broadband (eMBB) traffic. As another example, the UE 802 may select a single uplink transmit beam for transmission of the uplink signal for low data rate and delay insensitive traffic when the battery life of the UE 802 is low. As another example, the UE 802 may select a single uplink transmit beam for transmission of the uplink signal with multiple (e.g., X > 1) repetitions of the uplink transmit beam when a minimum data rate is not able to be maintained due to poor coverage. For example, the UE 802 may determine the number of repetitions (X) based on a measured downlink signal-to-noise ratio (SNR) of a DL RS, such as the SSB.

In some examples, the UE 802 may further be configured to select an uplink signal (e.g., PUCCH, PUSCH, SRS, or PRACH) to be applied to the selected uplink beam (s) selected during the uplink beam refinement. In this example, the at least one beam refinement parameter may include an indication of the uplink signal associated with the selected uplink beam (s) . In some examples, the uplink signal indication may include an uplink signal identifier of the uplink signal. For example, the uplink signal identifier may include a PUCCH resource identifier (ID) , a SRS resource ID, a SRS resource ID for PUSCH, a PRACH occasion (e.g., PRACH resources utilized for transmission of a random access message) , or a RACH preamble ID.

In other examples, the uplink signal indication may include a spatial identifier (ID) associated with an uplink transmit beam. The uplink transmit beam can be a current uplink transmit beam (e.g., the first uplink transmit beam utilized prior to uplink beam refinement) . For example, the spatial ID may include an uplink transmission configuration indicator (TCI) state ID of a TCI state, a spatial relation information ID of spatial relation information, or a spatial reference signal ID within the TCI state or the spatial relation information. The TCI state may indicate, for example, a spatial property of the current uplink transmit beam (e.g., a beam direction) of the uplink signal by association with the spatial property of a downlink reference signal. For example, the TCI state may indicate an associated SSB, CSI-RS, or tracking reference signal (TRS) waveform from which the current spatial property of the uplink signal may be inferred. Therefore, from the indicated TCI state ID or spatial reference signal ID within the TCI state, the base station 804 may identify the uplink signal to apply to the selected uplink beam (s) . Similarly, the spatial relation information may indicate the spatial property of the current uplink transmit beam applied to the uplink signal by association with a spatial property of an uplink reference signal (e.g., an SRS) . Therefore, from the indicated spatial relation ID or spatial reference signal ID within the spatial relation information, the base station 804 may identify the uplink signal to apply to the selected uplink beam (s) .

At 812, the base station 804 and the UE 802 may perform the uplink beam refinement based on the at least one beam refinement parameter to select the selected uplink beam (s) for uplink communication from the UE 802 to the base station 804. For example, the base station 804 may utilize a downlink beam management scheme or an uplink beam management scheme based on the selected beam management scheme included in the request to enable selection by the base station 804 and/or UE 802 of the selected uplink beam (s) . For example, when utilizing a downlink beam management scheme, the UE 802 may select the uplink transmit beam (s) based on the measured downlink beam reference signals. As another example, when utilizing an uplink beam management scheme, the base station 804 may select the uplink transmit beam (s) and notify the UE 802 of the selected uplink transmit beam (s) .

At 814, the UE 802 may communicate with the base station 804 on the selected uplink beam (s) . In some examples, the UE 802 may communicate an uplink signal (e.g., PUCCH, PUSCH, SRS, or PRACH) on the selected uplink beam (s) in accordance with the uplink transmission parameters included in the request. In some examples, the UE 802 may transmit a particular uplink signal on the selected uplink beam (s) based on the uplink signal indication included in the request.

FIG. 9 is a signaling diagram illustrating an example of signaling between a UE 902 and a base station 904 for obtaining an uplink grant for requesting uplink beam refinement according to some aspects. The UE 902 may correspond to any of the UEs or scheduled entities shown in FIGs. 1, 2, and/or 4–8. In addition, the base station 904 may correspond to any of the base stations or scheduling entities shown in FIG. s1, 2, and/or 4–8.

At 906, the UE 902 may communicate with the base station 904 using at least a first uplink beam. The first uplink beam may correspond, for example, to an uplink transmit beam of the UE 902. The uplink transmit beam may form an uplink beam pair link (BPL) with an uplink receive beam of the base station 904 for the transmission of one or more uplink signals, such as a PUCCH, PUSCH, SRS, or PRACH. In some examples, the UE 902 and base station 904 may communicate using two or more uplink BPLs.

At 908, the UE 902 may determine that uplink beam refinement may be needed to refine the uplink BPL (s) . For example, the UE 902 may determine that the uplink BPL has degraded due to UE movement, UE rotation, or an MPE limit violation. The uplink BPL (s) may be refined, for example, by selecting at least one selected uplink beam for uplink communication. In some examples, the selected uplink beam (s) may include one or more new (different) uplink transmit beams, each of which may form a respective BPL with a corresponding uplink receive beam, which may be the same or different uplink receive beam (s) . In other examples, the selected uplink beam (s) may include the same uplink transmit beam (s) , but different uplink receive beam (s) .

At 910, the UE 902 may transmit a scheduling request to the base station 904 requesting an uplink grant for transmission of a request for uplink beam refinement. The scheduling request may be transmitted, for example, within UCI of a PUCCH. At 912, the base station 904 may transmit an uplink grant for a PUSCH to carry the uplink beam refinement request. The uplink grant may be transmitted, for example, within DCI of a PDCCH. At 914, the UE 902 may transmit the PUSCH including the request for the uplink beam refinement to the base station 904 based on the uplink grant.

FIG. 10 is a signaling diagram illustrating an example of random access signaling between a UE 1002 and a base station 1004 to request uplink beam refinement according to some aspects. The UE 1002 may correspond to any of the UEs or scheduled entities shown in FIGs. 1, 2, and/or 4–8. In addition, the base station 1004 may correspond to any of the base stations or scheduling entities shown in FIG. s1, 2, and/or 4–8.

RACH procedures may be performed in various scenarios, such as loss of uplink synchronization, lack of available PUCCH resources, scheduling request failure, and other use cases. In addition, a RACH procedure may be contention-based or contention-free and may include a 2-step RACH process (contention-based or contention-free) , or a 4-step RACH process (contention-based or contention-free) . The example shown in FIG. 10 is a 4-step contention-based random access (CBRA) procedure.

At 1006, the UE 1002 may determine that uplink beam refinement may be needed to refine the uplink BPL (s) . For example, the UE 1002 may determine that an uplink BPL used for uplink communication from the UE 1002 to the base station 1004 has degraded due to UE movement, UE rotation, or an MPE limit violation. The uplink BPL (s) may be refined, for example, by selecting at least one selected uplink beam for uplink communication. In some examples, the selected uplink beam (s) may include one or more new (different) uplink transmit beams, each of which may form a respective BPL with a corresponding uplink receive beam, which may be the same or different uplink receive beam (s) . In other examples, the selected uplink beam (s) may include the same uplink transmit beam (s) , but different uplink receive beam (s) .

The UE 1002 may then initiate the 4-step RACH process by randomly selecting a preamble from an available set of preambles within the cell served by the base station 1004, and transmitting the selected preamble to the base station 1004 in a RACH preamble message 1008 (Msg1) . In some examples, the selected preamble may include a special RACH preamble indicating a request for uplink beam refinement. In this example, the base station 1004 may complete the RACH process, as described below, and then initiate the uplink beam refinement. The special RACH preamble may further indicate at least one beam refinement parameter, such as a beam management scheme (e.g., downlink or uplink) . For example, a first special RACH preamble may request a downlink beam management scheme, while a second special RACH preamble may request an uplink beam management scheme. Other special RACH preambles may further be defined to indicate other beam refinement parameters, as described above.

The Msg1 1008 may be transmitted by the UE 1002 over a selected PRACH resource with power ramping. The selected PRACH resource may include supplementary uplink resources or normal uplink resources. Here, supplementary uplink resources include lower frequency resources than normal uplink resources. Thus, supplementary uplink resources and normal uplink resources each correspond to a different respective uplink frequency band. The Msg1 1008 may further be communicated on an uplink transmit beam previously applied to PRACH messages or on an uplink transmit beam selected by the UE 1002 based on beam measurements (e.g., RSRP/RSRQ/SINR) performed by the UE 1002. For example, the selected uplink transmit beam may have a spatial relation to, for example, a downlink SSB beam.

If the preamble is successfully detected by the base station 1004, the base station 1004 transmits a random access response (RAR) message 1010 (Msg2) including a PDCCH and PDSCH to the UE 1002. If no Msg2 (RAR) 1010 is received within a RAR window, the UE 1002 may retransmit Msg1 1008 with power boost. The Msg2 1010 (PDCCH + PDSCH) includes an identifier of the preamble sent by the UE 1002, a Timing Advance (TA) , a temporary cell radio network temporary identifier (TC-RNTI) or random access (RA) RNTI for the UE 1002 and a grant of assigned uplink (UL) resources. The PDCCH in Msg2 1010 may be scrambled with the RA-RNTI, which is a function of a RACH occasion (RO) (e.g., time-frequency resources allocated for RACH Msg1) that the UE 1002 used to send Msg1 1008. A MAC-CE within the PDSCH provides an acknowledgement of the reception of Msg1 and the UL grant. To receive Msg2 1010, the UE 1002 may monitor DCI 1_0 for the PDCCH scrambled with the RA-RNTI corresponding to the RO used by the UE 1002 to transmit Msg1 1006, and if detected, proceeds with PDSCH decoding. Upon receipt of the RAR message 1010, the UE 1002 compares the preamble ID to the preamble sent by the scheduled entity in the RACH preamble message 1008. If the preamble ID matches the preamble sent in the RACH preamble message 1008, the UE 1002 applies the timing advance and starts a contention resolution procedure.

Since the preamble is selected randomly by the scheduled entity, if another scheduled entity selects the same preamble in the same RO, a collision may result between the two scheduled entities. Any collisions may then be resolved using the contention resolution procedure. During contention resolution, the UE 1002 transmits an uplink message (Msg3) 1012 using the TA and assigned uplink resources in the PDSCH of Msg2 1010. The uplink message 1012 includes an identifier of the UE 1002 (UE-ID) for use by the scheduling entity in resolving any collisions. Although other scheduled entities may transmit colliding uplink messages utilizing the TA and assigned uplink resources, these colliding uplink messages will likely not be successfully decoded at the scheduling entity since the colliding uplink messages were transmitted with TAs that were not intended for those scheduled entities.

In some examples, the UE 1002 may include the request for uplink beam refinement within the payload of Msg3 1012. For example, Msg3 1012 may include a PUSCH and the UE 1002 may include a MAC-CE carrying the request for uplink beam refinement within the PUSCH payload. The request may include one or more beam refinement parameters, as described above.

Upon successfully decoding the uplink message, the base station 1004 transmits a contention resolution message 1014 to the UE 1002 (Msg4) . The contention resolution message 1014 may be, for example, an RRC-Connection Setup message. In addition, the contention resolution message 1014 includes the identifier of the UE 1002 that was received in the uplink message 1012. The UE 1002, upon receiving its own identity back in the contention resolution message 1014, concludes that the random access procedure was successful and completes the RRC connection setup process. Any other scheduled entity receiving the RRC-Connection Setup message with the identity of the UE 1002 will conclude that the random access procedure failed and re-initialize the random access procedure.

FIG. 11 is a signaling diagram illustrating another example of random access signaling between a UE 1102 and a base station 1104 to request uplink beam refinement according to some aspects. The UE 1102 may correspond to any of the UEs or scheduled entities shown in FIGs. 1, 2, and/or 4–8. In addition, the base station 1104 may correspond to any of the base stations or scheduling entities shown in FIG. s1, 2, and/or 4–8.

The four-step CBRA procedure shown in FIG. 10 can be compressed into a two-step random access procedure, as shown in FIG. 11. The two-step random-access procedure reduces overhead and latency associated with control signaling by removing a transmission in each direction between the UE 1102 and the base station 1104.

As in FIG. 10, at 1106, the UE 1102 may determine that uplink beam refinement may be needed to refine the uplink BPL (s) . For example, the UE 1102 may determine that an uplink BPL used for uplink communication from the UE 1102 to the base station 1104 has degraded due to UE movement, UE rotation, or an MPE limit violation. The uplink BPL (s) may be refined, for example, by selecting at least one selected uplink beam for uplink communication. In some examples, the selected uplink beam (s) may include one or more new (different) uplink transmit beams, each of which may form a respective BPL with a corresponding uplink receive beam, which may be the same or different uplink receive beam (s) . In other examples, the selected uplink beam (s) may include the same uplink transmit beam (s) , but different uplink receive beam (s) .

In comparison to FIG. 10, the two-step random-access procedure in FIG. 11 commences with a transmission by the UE 1102 of a single message (MsgA 1108) that includes the RACH preamble message and uplink message sent of the contention-based random-access procedure shown in FIG. 10. Here, the uplink message may be a scheduled PUSCH transmission sent over a PUSCH resource and the RACH preamble message may be sent over a selected PRACH resource. The base station 1104 responds with a single message (MsgB 1110) that includes the random-access response and the contention resolution message shown in FIG. 10.

In some examples, MsgA 1108 may include a special RACH preamble indicating the uplink beam refinement request. In other examples, the payload of the PUSCH of MsgA 1108 may include a MAC-CE carrying the request for uplink beam refinement. The request may further include one or more beam refinement parameters, as described above.

FIGs. 12A–12C are diagrams illustrating examples of beam sweep types for uplink beam refinement according to some aspects. FIG. 12A illustrates an example of a full range beam sweep in which the base station or UE may sweep all possible candidate beams at least at the coarse level. For example, the full range beam sweep may sweep at least a plurality of coarse (e.g., wider) beams 1202 (three of which are shown, for convenience) . FIG 12B illustrates an example of a local beam sweep in which the base station or UE may sweep a plurality of narrow beams 1204 within a selected coarse beam 1202. FIG. 12C illustrates an example of beam repetition in which the base station or UE may repeat transmission of a selected narrow beam 1204 a number of times to enable beam refinement. In the example shown in FIG. 12C, the selected narrow beam 1204 is transmitted at a first time (t ₁) , and then repeated at a second time (t ₂) and a third time (t ₃) .

FIGs. 13A–13C are diagrams illustrating exemplary multiplexing of multiple selected uplink beams according to some aspects. In the examples shown in FIGs. 13A–13C, two uplink transmit beams (Beam 1 1302a and Beam 2 1302b) are illustrated for transmitting an uplink signal. Each uplink transmit

beam

1302a and 1302b may transmit a respective portion of the uplink signal or the uplink signal may be repeated across each of the

beams

1302a and 1302b. The uplink signal may be, for example, a PUCCH, PUSCH, SRS, or PRACH. In addition, in each of FIGs. 13A–13C, time is illustrated along the horizontal axis and frequency is illustrated along the vertical axis.

FIG. 13A illustrates an example of frequency division multiplexing (FDM) of the uplink transmit

beams

1302a and 1302b. In this example, the uplink signal may be transmitted in the same time resources (e.g., within the same symbols of a slot) , but different frequency resources (e.g., different subcarriers) for each of the uplink transmit

beams

1302a and 1302b. For example, the UE may include multiple (e.g., two) antenna panels, and each antenna panel may be used to generate a respective one of the FDMed uplink transmit

beams

1302a and 1302b. FIG. 13B illustrates an example of time division multiplexing (TDM) of the uplink transmit

beams

1302a and 1302b. In this example, the uplink signal may be transmitted in the same frequency resources, but in different time resources (e.g., different symbols or slots) for each of the uplink transmit

beams

1302a and 1302b. For example, the UE may include one or more antenna panels for transmission of the TDMed uplink transmit

beams

1302a and 1302b. FIG. 13C illustrates an example of spatial division multiplexing (SDM) of the uplink transmit

beams

1302a and 1302b. In this example, the uplink signal may be transmitted in the same time–frequency resources for each of the uplink transmit

beams

1302a and 1302b. For example, the UE may include two antenna panels, each for generating one of the uplink transmit

beams

1302a and 1302b.

FIG. 14 is a diagram illustrating exemplary beam repetitions of selected uplink beams according to some aspects. In the example shown in FIG. 14, two uplink transmit beams (Beam 1 1402a and Beam 2 1402b) are illustrated for transmitting an uplink signal. Each uplink transmit

beam

1402a and 1402b may transmit a respective portion of the uplink signal or the uplink signal may be repeated across each of the

beams

1402a and 1402b. The uplink signal may be, for example, a PUCCH, PUSCH, SRS, or PRACH. In addition, in FIG. 14, time is illustrated along the horizontal axis and frequency is illustrated along the vertical axis.

In the example shown in FIG. 14, each uplink transmit

beam

1402a and 1402b is transmitted twice and all of the uplink transmit

beams

1402a and 1402b are TDMed. In other examples, the number of repetitions per beam may be more than one and the number of repetitions per beam may vary between the uplink transmit

beams

1402a and 1402b. In addition, other multiplexing schemes may be used to transmit the uplink transmit

beams

1402a and 1402b and the repetitions may be TDMed.

FIG. 15 is a conceptual diagram illustrating an example of a hardware implementation for an exemplary UE 1500 employing a processing system 1514. For example, the UE 1500 may be any of the UEs or scheduled entities illustrated in any one or more of FIGs. 1, 2, and/or 4–11.

The UE 1500 may be implemented with a processing system 1514 that includes one or more processors 1504. Examples of processors 1504 include microprocessors, microcontrollers, digital signal processors (DSPs) , field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. In various examples, the UE 1500 may be configured to perform any one or more of the functions described herein. That is, the processor 1504, as utilized in a UE 1500, may be used to implement any one or more of the processes described below in connection with FIG. 15.

The processor 1504 may in some instances be implemented via a baseband or modem chip and in other implementations, the processor 1504 may itself comprise a number of devices distinct and different from a baseband or modem chip (e.g., in such scenarios as may work in concert to achieve embodiments discussed herein) . And as mentioned above, various hardware arrangements and components outside of a baseband modem processor can be used in implementations, including RF-chains, power amplifiers, modulators, buffers, interleavers, adders/summers, etc.

In this example, the processing system 1514 may be implemented with a bus architecture, represented generally by the bus 1502. The bus 1502 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1514 and the overall design constraints. The bus 1502 communicatively couples together various circuits including one or more processors (represented generally by the processor 1504) , a memory 1505, and computer-readable media (represented generally by the computer-readable medium 1506) . The bus 1502 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further. A bus interface 1508 provides an interface between the bus 1502 and a transceiver 1510. The transceiver 1510 provides a means for communicating with various other apparatus over a transmission medium (e.g., air interface) . A user interface 1512 (e.g., keypad, display, speaker, microphone, joystick) may also be provided.

The processor 1504 is responsible for managing the bus 1502 and general processing, including the execution of software stored on the computer-readable medium 1506. The software, when executed by the processor 1504, causes the processing system 1514 to perform the various functions described below for any particular apparatus. The computer-readable medium 1506 and the memory 1505 may also be used for storing data that is manipulated by the processor 1504 when executing software.

One or more processors 1504 in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium 1506.

The computer-readable medium 1506 may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip) , an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD) ) , a smart card, a flash memory device (e.g., a card, a stick, or a key drive) , a random access memory (RAM) , a read only memory (ROM) , a programmable ROM (PROM) , an erasable PROM (EPROM) , an electrically erasable PROM (EEPROM) , a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium 1506 may reside in the processing system 1514, external to the processing system 1514, or distributed across multiple entities including the processing system 1514. The computer-readable medium 1506 may be embodied in a computer program product. In some examples, the computer-readable medium 1506 may be part of the memory 1505. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

In some aspects of the disclosure, the processor 1504 may include circuitry configured for various functions. For example, the processor 1504 may include communication and processing circuitry 1542, configured to communicate with a base station, such as a gNB. In some examples, the communication and processing circuitry 1542 may include one or more hardware components that provide the physical structure that performs processes related to wireless communication (e.g., signal reception and/or signal transmission) and signal processing (e.g., processing a received signal and/or processing a signal for transmission) .

In some examples, the communication and processing circuitry 1542 may be configured to receive and process downlink beamformed signals at a mmWave frequency or a sub-6 GHz frequency via the transceiver 1510 and an antenna array 1530. For example, the communication and processing circuitry 1542 may be configured to receive a respective reference signal (e.g., SSB or CSI-RS) on each of a plurality of downlink beams from the base station during a downlink beam sweep. The communication and processing circuitry 1542 may further be configured to transmit a beam measurement report to the base station.

In some examples, the communication and processing circuitry 1542 may further be configured to generate and transmit uplink beamformed signals at a mmWave frequency or a sub-6 GHz frequency via the transceiver 1510 and the antenna array 1530. For example, the communication and processing circuitry 1542 may be configured to transmit a respective reference signal (e.g., SRS) on each of a plurality of uplink beams to the base station during an uplink beam sweep.

The communication and processing circuitry 1542 may further be configured to generate and transmit a request for uplink beam refinement to the base station. For example, the request may be included in a MAC-CE carried in a PUSCH, UCI in a PUCCH or PUSCH, a random access message, or an RRC message. The communication and processing circuitry 1542 may further be configured to generate and transmit a scheduling request (e.g., via UCI in a PUCCH) to the base station to receive an uplink grant for the PUSCH carrying the MAC-CE including the request for uplink beam refinement.

The communication and processing circuitry 1542 may further be configured to generate and transmit an uplink signal on one or more uplink transmit beams applied to the uplink signal. The uplink signal may include, for example, a PUCCH, PUSCH, SRS, or PRACH. The communication and processing circuitry 1542 may further be configured to execute communication and processing software 1552 stored in the computer-readable medium 1506 to implement one or more of the functions described herein.

The processor 1504 may further include uplink beam configuration circuitry 1544, configured to apply one or more uplink transmit beams to an uplink signal. For example, the uplink beam configuration circuitry 1544 may be configured to determine a transmission scheme for transmitting an uplink signal based on uplink transmission parameters 1522. The uplink transmission parameters 1522 may be stored, for example, in memory 1505. The uplink transmission parameters 1522 may include, for example, the number of uplink transmit beams to use for transmission of the uplink signal, the number of repetitions per beam, and the multiplexing scheme when the number of uplink transmit beams is greater than one.

As another example, the uplink beam configuration circuitry 1544 may identify the selected uplink transmit beam (s) for the uplink signal based on a mapping between the uplink signal and a respective TCI state or spatial relation information associated with each of the uplink transmit beams. The mapping may be stored, for example, as part of the uplink transmission parameters 1522 within memory 1505. The uplink beam configuration circuitry 1544 may further be configured to execute uplink beam configuration software 1554 stored in the computer-readable medium 1506 to implement one or more of the functions described herein.

The processor 1504 may further include uplink beam refinement circuitry 1546, configured to determine that an uplink beam refinement of the uplink BPLs is needed. For example, the uplink beam refinement circuitry 1546 may be configured to determine that an uplink beam refinement is needed due to movement of the UE 1500, rotation of the UE 1500, or detection of a maximum permissible exposure (MPE) limit violation at the UE 1500.

The uplink beam refinement circuitry 1546 may further be configured to select one or more beam refinement parameters 1520 for the uplink beam refinement. The selected beam refinement parameters 1520 may be stored, for example, in memory 1505. For example, the uplink beam refinement circuitry 1546 may be configured to select a beam management scheme to utilize for the uplink beam refinement. For example, the selected beam management scheme may be an uplink beam management scheme or a downlink beam management scheme. In this example, the beam refinement parameter (s) 1520 may include an indication of the selected beam management scheme. In addition, the uplink beam refinement circuitry 1546 may be configured to select a beam sweep type (e.g., full range, local, or beam repetition) for the selected beam management scheme, along with a number of reference signal resources (e.g., SSB resources, CSI-RS resources, or SRS resources) for the selected beam management scheme. The selected beam sweep type and number of reference signal resources may further be included in the beam refinement parameter (s) 1520.

In some examples, the uplink beam refinement circuitry 1546 may further be configured to select an uplink transmission scheme to utilize for one or more selected uplink beam (s) selected during the uplink beam refinement. For example, the selected uplink transmission scheme may be used to transmit an uplink signal (e.g., PUSCH, PUCCH, SRS, or PRACH) on the selected uplink beam (s) . In this example, the beam refinement parameter (s) 1520 may include at least one uplink transmission parameter 1522 associated with the uplink transmission scheme. For example, the at least one uplink transmission parameter 1522 may indicate a number of uplink transmit beams to utilize for transmission of the uplink signal, a multiplexing scheme (FDM, TDM, or SDM) when the number of uplink transmit beams is greater than one, and/or a number of repetitions of each of the uplink transmit beams for transmission of the uplink reference signal.

In some examples, the uplink beam refinement circuitry 1546 may be configured to select the uplink transmission scheme and corresponding uplink transmission parameter (s) based on one or more of an amount of buffered uplink traffic, quality of service (QoS) requirements for the uplink traffic, or the battery life (e.g., of power source 1540) of the UE 1500. For example, the uplink beam refinement circuitry 1546 may be configured to select TDM or FDM of multiple uplink transmit beams for transmission of the uplink signal for delay sensitive traffic, such as ultra-reliable low-latency communication (URLLC) traffic. As another example, the uplink beam refinement circuitry 1546 may be configured to select SDM of multiple uplink transmit beams for transmission of the uplink signal for high data rate traffic, such as enhanced mobile broadband (eMBB) traffic. As another example, the uplink beam refinement circuitry 1546 may be configured to select a single uplink transmit beam for transmission of the uplink signal for low data rate and delay insensitive traffic when the life of the power source 1540 is low. As another example, the uplink beam refinement circuitry 1546 may be configured to select a single uplink transmit beam for transmission of the uplink signal with multiple (e.g., X > 1) repetitions of the uplink transmit beam when a minimum data rate is not able to be maintained due to poor coverage. For example, the uplink beam refinement circuitry 1546 may determine the number of repetitions (X) based on a measured downlink signal-to-noise ratio (SNR) of a DL RS, such as the SSB.

In some examples, the uplink beam refinement circuitry 1546 may further be configured to select an uplink signal (e.g., PUCCH, PUSCH, SRS, or PRACH) to be applied to the selected uplink beam (s) selected during the uplink beam refinement. In this example, the beam refinement parameter (s) 1520 may include an indication of the uplink signal associated with the selected uplink beam (s) . In some examples, the uplink signal indication may include an uplink signal identifier of the uplink signal. For example, the uplink signal identifier may include a PUCCH resource identifier (ID) , a SRS resource ID, a SRS resource ID for PUSCH, a PRACH occasion (e.g., PRACH resources utilized for transmission of a random access message) , or a RACH preamble ID. In other examples, the uplink signal indication may include a spatial identifier (ID) associated with a current uplink transmit beam (e.g., the first uplink transmit beam utilized prior to uplink beam refinement) . For example, the spatial ID may include an uplink transmission configuration indicator (TCI) state ID of a TCI state currently associated with the uplink signal, a spatial relation information ID of spatial relation information, or a spatial reference signal ID within the TCI state or the spatial relation information.

The uplink beam refinement circuitry 1546 may further be configured to generate a request for the uplink beam refinement and to include one or more of the beam refinement parameters 1520 within the request. The uplink beam refinement circuitry 1546 may further be configured to operate together with the communication and processing circuitry 1542 to transmit the request to the base station via a MAC-CE carried in a PUSCH, UCI in a PUCCH or PUSCH, a random access message, or an RRC message.

The uplink beam refinement circuitry 1546 may further be configured to control the antenna array 1530 and transceiver 1510 to perform the uplink beam refinement based on the beam refinement parameter (s) 1520. In an example of a downlink beam management scheme, the uplink beam refinement circuitry 1546 may be configured to search for and identify a plurality of downlink transmit beams during a downlink beam sweep based on a selected beam sweep type. The uplink beam refinement circuitry 1546 may further be configured to obtain a plurality of beam measurements on each of a plurality of downlink receive beams of the antenna array 1530 for each of the identified downlink transmit beams. The uplink beam refinement circuitry 1546 may further be configured to generate a beam measurement report for transmission to the base station using the communication and processing circuitry 1542.

The uplink beam refinement circuitry 1546 may further be configured to identify one or more selected uplink beam (s) based on the beam measurements obtained from the downlink beam reference signals. In some examples, the uplink beam refinement circuitry 1546 may be configured to compare the respective RSRP (or other beam measurement) measured on each of the downlink receive beams for each of the serving downlink transmit beams to identify the serving downlink receive beams and to further utilize the serving downlink receive beams as the selected uplink transmit beams. Each serving downlink receive beam may have the highest measured RSRP (or other beam measurement) for one of the downlink transmit beams.

In an example of an uplink beam management scheme, the uplink beam refinement circuitry 1546 may be configured to generate one or more uplink transmit beams for transmission in an uplink beam sweep based on a selected beam sweep type (e.g., as indicated in the beam refinement parameter (s) 1520) . Each uplink transmit beam may carry an uplink reference signal (e.g., an SRS) for measurement by the base station. The uplink beam refinement circuitry 1546 may further be configured to identify the selected uplink transmit beam (s) selected by the base station based on the uplink beam measurements. For example, the uplink beam refinement circuitry 1546 may be configured to receive an indication of the selected uplink transmit beam (s) from the base station. The uplink beam refinement circuitry 1546 may further be configured to execute uplink beam refinement software 1556 stored in the computer-readable medium 1506 to implement one or more of the functions described herein.

FIG. 16 is a conceptual diagram illustrating an example of a hardware implementation for an exemplary base station 1600 employing a processing system 1614. For example, the base station 1600 may be any of the base stations (e.g., gNBs) or scheduling entities illustrated in any one or more of FIGs. 1, 2, and/or 4–11.

In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a processing system 1614 that includes one or more processors 1604. The processing system 1614 may be substantially the same as the processing system 1514 illustrated in FIG. 15, including a bus interface 1608, a bus 1602, memory 1605, a processor 1604, and a computer-readable medium 1606. Furthermore, the base station 1600 may include an optional user interface 1612 and a transceiver 1610 substantially similar to those described above in FIG. 15. That is, the processor 1604, as utilized in a base station 1600, may be used to implement any one or more of the processes described below.

In some aspects of the disclosure, the processor 1604 may include circuitry configured for various functions. For example, the processor 1604 may include resource assignment and scheduling circuitry 1642, configured to generate, schedule, and modify a resource assignment or grant of time–frequency resources (e.g., a set of one or more resource elements) . For example, the resource assignment and scheduling circuitry 1642 may schedule time–frequency resources within a plurality of time division duplex (TDD) and/or frequency division duplex (FDD) subframes, slots, and/or mini-slots to carry user data traffic and/or control information to and/or from multiple UEs.

In some examples, the resource assignment and scheduling circuitry 1642 may be configured to schedule resources for the transmission of downlink reference signals (e.g., SSBs or CSI-RSs) on a plurality of downlink beams for a downlink beam sweep in accordance with a selected downlink beam sweep type and selected number of downlink reference signal resources indicated in a request for uplink beam refinement received from a UE. The resource assignment and scheduling circuitry 1642 may further be configured to schedule resources for the uplink transmission of uplink reference signals (e.g., SRSs) on a plurality of uplink beams for an uplink beam sweep in accordance with a selected beam sweep type and selected number of uplink reference signal resources indicated in the request. The resource assignment and scheduling circuitry 1642 may further be configured to schedule resources that may be utilized by the UE to transmit the request. For example, the uplink beam refinement request resources may include resources scheduled for transmission of a PUCCH, PUSCH, PRACH occasion or RRC message. In some examples, the resource assignment and scheduling circuitry 1642 may be configured to schedule PUSCH resources for the uplink beam refinement request in response to receiving a scheduling request from the UE.

The resource assignment and scheduling circuitry 1642 may further be configured to schedule resources for the transmission of an uplink signal. In some examples, the resources may be associated with one or more uplink transmit beams and one or more corresponding receive beams applied to the uplink signal (e.g., based on the uplink BPLs) based on an indication of the uplink signal associated with the one or more uplink transmit beams included in the request. In some examples, the resources may be associated with an uplink transmission scheme indicating a number of uplink transmit beams to be utilized for the uplink signal, a number of repetitions per uplink transmit beam of the uplink signal, and a multiplexing scheme when more than one uplink transmit beam is used to transmit the uplink signal. The resource assignment and scheduling circuitry 1642 may further be configured to execute resource assignment and scheduling software 1652 stored in the computer-readable medium 1606 to implement one or more of the functions described herein.

The processor 1604 may further include communication and processing circuitry 1644, configured to communicate with a UE. In some examples, the communication and processing circuitry 1644 may include one or more hardware components that provide the physical structure that performs processes related to wireless communication (e.g., signal reception and/or signal transmission) and signal processing (e.g., processing a received signal and/or processing a signal for transmission) .

In some examples, the communication and processing circuitry 1644 may be configured to receive and process uplink beamformed signals at a mmWave frequency or a sub-6 GHz frequency via the transceiver 1610 and an antenna array 1630. For example, the communication and processing circuitry 1644 may be configured to receive a respective reference signal (e.g., SRS) on each of a plurality of uplink beams from the UE during an uplink beam sweep.

In some examples, the communication and processing circuitry 1644 may further be configured to generate and transmit downlink beamformed signals at a mmWave frequency or a sub-6 GHz frequency via the transceiver 1610 and the antenna array 1630. For example, the communication and processing circuitry 1644 may be configured to transmit a respective downlink reference signal (e.g., SSB or CSI-RS) on each of a plurality of downlink beams to the UE during a downlink beam sweep. The communication and processing circuitry 1644 may further be configured to receive a beam measurement report from the UE.

The communication and processing circuitry 1644 may further be configured to receive the request for uplink beam refinement from the UE. For example, the request may be included in a MAC-CE carried in a PUSCH, UCI in a PUCCH or PUSCH, a random access message, or an RRC message. The communication and processing circuitry 1644 may further be configured to receive a scheduling request (e.g., via UCI in a PUCCH) from the UE for an uplink grant for the PUSCH carrying the MAC-CE including the request for uplink beam refinement.

The communication and processing circuitry 1644 may further be configured to receive an uplink signal on one or more uplink receive beams via one or more uplink transmit beams applied to the uplink signal. In some examples, the one or more uplink transmit beams and one or more uplink receive beams may correspond to selected uplink beam (s) selected based on the uplink beam refinement. In this example, the uplink signal may be received via a number of uplink transmit beams with a number of repetitions per beam and based on a selected multiplexing scheme as indicated in the request for uplink beam refinement. For example, the request may include a selected uplink transmission scheme including one or more uplink transmission parameters associated with the uplink signal. The uplink signal may include, for example, a PUCCH, PUSCH, SRS, or PRACH. The communication and processing circuitry 1644 may further be configured to execute communication and processing software 1654 stored in the computer-readable medium 1606 to implement one or more of the functions described herein.

The processor 1604 may further include uplink beam refinement circuitry 1646, configured to receive a request for uplink beam refinement from the UE via, for example, a MAC-CE carried in a PUSCH, UCI in a PUCCH or PUSCH, a random access message, or an RRC message. The request may include at least one beam refinement parameter 1620. The beam refinement parameter (s) 1620 may be stored, for example, in memory 1605. In some examples, the beam refinement parameter (s) 1620 may include a selected beam management scheme to utilize for the uplink beam refinement. For example, the selected beam management scheme may be an uplink beam management scheme or a downlink beam management scheme. In this example, the beam refinement parameter (s) 1620 may further include a selected beam sweep type (e.g., full range, local, or beam repetition) for the selected beam management scheme, along with a number of reference signal resources (e.g., SSB resources, CSI-RS resources, or SRS resources) for the selected beam management scheme.

In some examples, the beam refinement parameter (s) 1620 may further include a selected uplink transmission scheme to utilize for one or more selected uplink beam (s) selected during the uplink beam refinement. For example, the selected uplink transmission scheme may be associated with transmission of an uplink signal (e.g., PUSCH, PUCCH, SRS, or PRACH) on the selected uplink beam (s) . In this example, the beam refinement parameter (s) 1620 may include at least one uplink transmission parameter 1622 associated with the uplink transmission scheme. For example, the at least one uplink transmission parameter 1622 may indicate a number of uplink transmit beams for the UE to utilize for transmission of the uplink signal, a multiplexing scheme (FDM, TDM, or SDM) when the number of uplink transmit beams is greater than one, and/or a number of repetitions of each of the uplink transmit beams for transmission of the uplink reference signal.

In some examples, the beam refinement parameter (s) 1620 may include an indication of an uplink signal to be associated with the selected uplink beam (s) selected during the uplink beam refinement. In some examples, the uplink signal indication may include an uplink signal identifier of the uplink signal. For example, the uplink signal identifier may include a PUCCH resource identifier (ID) , a SRS resource ID, a SRS resource ID for PUSCH, a PRACH occasion (e.g., PRACH resources utilized for transmission of a random access message) , or a RACH preamble ID. In other examples, the uplink signal indication may include a spatial identifier (ID) associated with a current uplink transmit beam (e.g., the first uplink transmit beam utilized prior to uplink beam refinement) . For example, the spatial ID may include an uplink transmission configuration indicator (TCI) state ID of a TCI state currently associated with the uplink signal, a spatial relation information ID of spatial relation information, or a spatial reference signal ID within the TCI state or the spatial relation information.

The uplink beam refinement circuitry 1646 may further be configured to control the antenna array 1630 and transceiver 1610 to perform the uplink beam refinement based on the beam refinement parameter (s) 1620. In an example of a downlink beam management scheme, the uplink beam refinement circuitry 1646 may be configured to generate a plurality of downlink transmit beams during a downlink beam sweep based on the selected beam sweep type. The uplink beam refinement circuitry 1646 may further be configured to receive a beam measurement report from the UE using the communication and processing circuitry 1644. The uplink beam refinement circuitry 1646 may further be configured to identify one or more selected uplink beam (s) based on the beam measurements. In some examples, the uplink beam refinement circuitry 1646 may be configured to compare the respective RSRP (or other beam measurement) measured on each of the downlink receive beams for each of the serving downlink transmit beams to identify the serving downlink receive beams and to further identify the serving downlink receive beams as the selected uplink transmit beams. Each serving downlink receive beam may have the highest measured RSRP (or other beam measurement) for one of the downlink transmit beams.

In an example of an uplink beam management scheme, the uplink beam refinement circuitry 1646 may be configured to receive one or more uplink transmit beams in an uplink beam sweep based on a selected beam sweep type (e.g., as indicated in the beam refinement parameter (s) 1620) . Each uplink transmit beam may carry an uplink reference signal (e.g., an SRS) for measurement by the uplink beam refinement circuitry 1646. The uplink beam refinement circuitry 1646 may further be configured to obtain a plurality of beam measurements on each of a plurality of uplink receive beams of the antenna array 1630 for each of the uplink transmit beams. The uplink beam refinement circuitry 1646 may further be configured to select the selected uplink transmit beam (s) and corresponding uplink receive beams forming respective uplink BPLs based on the uplink beam measurements. The uplink beam refinement circuitry 1646 may further be configured to execute uplink beam refinement software 1656 stored in the computer-readable medium 1606 to implement one or more of the functions described herein.

FIG. 17 is a flow chart 1700 illustrating an example of a method for a UE to request uplink beam refinement according to some aspects. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the method may be performed by the UE 1500, as described above and illustrated in FIG. 15, by a processor or processing system, or by any suitable means for carrying out the described functions.

At block 1702, the UE may communicate with a base station using at least a first uplink beam of a plurality of uplink beams. The first uplink beam may correspond, for example, to an uplink transmit beam of the UE. The uplink transmit beam may form an uplink beam pair link (BPL) with an uplink receive beam of the base station for the transmission of one or more uplink signals, such as a PUCCH, PUSCH, SRS, or PRACH. In some examples, the UE and base station may communicate using two or more uplink BPLs. For example, the communication and processing circuitry 1542, together with the uplink beam configuration circuitry 1544, transceiver 1510 and antenna array 1530, shown and described above in connection to FIG. 15, may communicate with the base station using a first uplink beam.

At block 1704, the UE may transmit a request for an uplink beam refinement to the base station. The request can include at least one beam refinement parameter. In some examples, the UE may be configured to select a selected beam management scheme to utilize for the uplink beam refinement. The selected beam management scheme may be an uplink beam management scheme or a downlink beam management scheme. The at least one beam confinement parameter may include an indication of the selected beam management scheme.

In some examples, the UE may further be configured to select a selected beam sweep type selected from a full range beam sweep of at least a plurality of coarse beams, a local beam sweep of a plurality of narrow beams within a selected coarse beam of the plurality of coarse beams, or a beam repetition of a selected narrow beam within the plurality of narrow beams. The at least one beam refinement parameter may further include an indication of the selected beam sweep type. In addition, the at least one beam refinement parameter may further include a number of reference signal resources associated with a reference signal utilized for the selected beam sweep type. For example, the reference signal may be a sounding reference signal (SRS) when the selected beam management scheme is the uplink beam management scheme. In addition, the reference signal may be a synchronization signal block (SSB) or channel state information (CSI) reference signal (CSI-RS) when the selected beam management scheme is the downlink beam management scheme.

In some examples, the UE may further be configured to select an uplink transmission scheme to utilize for the at least one second uplink beam. The at least one beam refinement parameter may include at least one uplink transmission parameter associated with the uplink transmission scheme. For example, the at least one uplink transmission parameter may include a number of the at least one second uplink beam to utilize for transmission of an uplink signal. The at least one uplink transmission parameter may further include a multiplexing scheme for the at least one second uplink beam when the number of the at least one second uplink beam is greater than one. The multiplexing scheme may be time division multiplexing, frequency division multiplexing, or spatial division multiplexing. The at least one uplink transmission parameter may further include a number of repetitions of each of the at least one second uplink beam for transmission of an uplink signal.

In some examples, the at least one beam refinement parameter may further include an indication of an uplink signal associated with the at least one second uplink beam. The uplink signal may be a physical uplink control channel (PUCCH) , physical uplink shared channel (PUSCH) , a sounding reference signal (SRS) , or a physical random access channel (PRACH) . For example, the indication of the uplink signal may be an uplink signal identifier of the uplink signal. The uplink signal identifier may be a PUCCH resource identifier (ID) , a SRS resource ID, a SRS resource indicator ID for PUSCH, a PRACH occasion or a preamble ID. As another example, the indication of the uplink signal may include a first spatial identifier (ID) associated with the first uplink beam. The first spatial identifier associated with the first uplink beam may be an uplink transmission configuration indicator (TCI) state ID of a TCI state, a spatial relation information ID of spatial relation information, or a spatial reference signal ID within the TCI state or the spatial relation information. The UE may further be configured to apply a second spatial identifier associated with a second uplink beam of the at least one second uplink beam to the uplink signal when the second uplink beam is different than the first uplink beam. In some examples, the first uplink beam is a first uplink transmit beam at the UE forming a first beam pair link with a first uplink receive beam at the base station. The UE may further be configured to form a second beam pair link between a second uplink receive beam at the base station and the first uplink transmit beam when the at least one second uplink beam includes the first uplink transmit beam.

In some examples, the UE may transmit the request for the uplink beam refinement within a medium access control (MAC) control element (MAC-CE) of a physical uplink shared channel (PUSCH) . For example, the UE may utilize an existing uplink grant for the PUSCH to transmit the MAC-CE including the request for the uplink beam refinement. As another example, the UE may transmit a scheduling request for an uplink grant for the PUSCH to transit the MAC-CE including the request for the uplink beam refinement. In some examples, the UE may transmit the request for the uplink beam refinement within uplink control information of a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) . In some examples, the UE may transmit the request for the uplink beam refinement within a random access message. For example, the random access message may include a random access channel RACH preamble. As another example, the random access message may include a physical uplink shared channel (PUSCH) payload. The PUSCH payload may include a medium access control (MAC) control element (MAC-CE) including the request for the uplink beam refinement. In some examples, the UE may transmit the request for the uplink beam refinement within an uplink radio resource control (RRC) message. For example, the uplink beam refinement circuitry 1546, together with the communication and processing circuitry 1542 and transceiver 1510, shown and described above in connection with FIG. 15 may transmit the request for the uplink beam refinement.

At block 1706, the UE may perform the uplink beam refinement based on the at least one beam refinement parameter included in the request. For example, the UE may utilize a downlink beam management scheme or an uplink beam management scheme based on the selected beam management scheme included in the request. In addition, the UE may utilize a beam sweep type and number of reference signal resources for the beam sweep type indicated in the request to perform the uplink beam refinement. For example, the uplink beam refinement circuitry 1546, together with the communication and processing circuitry 1542 and transceiver 1510, shown and described above in connection with FIG. 15 may perform the uplink beam refinement.

At block 1708, the UE may identify at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the base station. For example, when utilizing a downlink beam management scheme, the UE may select the at least one second uplink beam based on the measured downlink beam reference signals. As another example, when utilizing an uplink beam management scheme, the base station may select the at least one second uplink beam and notify the UE of the selected second uplink transmit beam (s) . For example, the uplink beam refinement circuitry 1546, together with the communication and processing circuitry 1542 and transceiver 1510, shown and described above in connection with FIG. 15 may identify the at least one second uplink beam.

In one configuration, the UE 1500 includes means for performing the various functions and processes described in relation to FIG. 17. In one aspect, the aforementioned means may be the processor 1504 shown in FIG. 15 configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a circuit or any apparatus configured to perform the functions recited by the aforementioned means.

Of course, in the above examples, the circuitry included in the processor 1504 is merely provided as an example, and other means for carrying out the described functions may be included within various aspects of the present disclosure, including but not limited to the instructions stored in the computer-readable storage medium 1506, or any other suitable apparatus or means described in any one of the FIGs. 1, 2, and/or 4–11, and utilizing, for example, the processes and/or algorithms described herein in relation to FIG. 17.

FIG. 18 is a flow chart 1800 illustrating an example of a method for a base station to receive a request for uplink beam refinement according to some aspects. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the method may be performed by the base station 1600, as described above and illustrated in FIG. 16, by a processor or processing system, or by any suitable means for carrying out the described functions.

At block 1802, the base station may communicate with a UE using at least a first uplink beam of a plurality of uplink beams. The first uplink beam may correspond, for example, to an uplink transmit beam of the UE. The uplink transmit beam may form an uplink beam pair link (BPL) with an uplink receive beam of the base station for the transmission of one or more uplink signals, such as a PUCCH, PUSCH, SRS, or PRACH. In some examples, the UE and base station may communicate using two or more uplink BPLs. For example, the communication and processing circuitry 1644, together with the transceiver 1610 and antenna array 1630, shown and described above in connection with FIG. 16 may communicate with the UE using a first uplink beam.

At block 1804, the base station may receive a request for an uplink beam refinement from the UE. The request can include at least one beam refinement parameter. In some examples, the at least one beam refinement parameter may include an indication of a selected beam management scheme. The selected beam management scheme may be an uplink beam management scheme or a downlink beam management scheme.

In some examples, the at least one beam refinement parameter may include an indication of a selected beam sweep type selected from a full range beam sweep of at least a plurality of coarse beams, a local beam sweep of a plurality of narrow beams within a selected coarse beam of the plurality of coarse beams, or a beam repetition of a selected narrow beam within the plurality of narrow beams. In addition, the at least one beam refinement parameter may further include a number of reference signal resources associated with a reference signal utilized for the selected beam sweep type. For example, the reference signal may be a sounding reference signal (SRS) when the selected beam management scheme is the uplink beam management scheme. In addition, the reference signal may be a synchronization signal block (SSB) or channel state information (CSI) reference signal (CSI-RS) when the selected beam management scheme is the downlink beam management scheme.

In some examples, the at least one beam refinement parameter includes at least one uplink transmission parameter associated with an uplink transmission scheme to utilize for at least one second uplink beam selected during the uplink beam refinement. For example, the at least one uplink transmission parameter may include a number of the at least one second uplink beam to utilize for transmission of an uplink signal. The at least one uplink transmission parameter may further include a multiplexing scheme for the at least one second uplink beam when the number of the at least one second uplink beam is greater than one. The multiplexing scheme may be time division multiplexing, frequency division multiplexing, or spatial division multiplexing. The at least one uplink transmission parameter may further include a number of repetitions of each of the at least one second uplink beam for transmission of an uplink signal.

In some examples, the at least one beam refinement parameter may further include an indication of an uplink signal associated with the at least one second uplink beam. The uplink signal may be a physical uplink control channel (PUCCH) , physical uplink shared channel (PUSCH) , a sounding reference signal (SRS) , or a physical random access channel (PRACH) . For example, the indication of the uplink signal may be an uplink signal identifier of the uplink signal. The uplink signal identifier may be a PUCCH resource identifier (ID) , a SRS resource ID, a SRS resource indicator ID for PUSCH, a PRACH occasion or a preamble ID. As another example, the indication of the uplink signal may include a first spatial identifier (ID) associated with the first uplink beam. The first spatial identifier associated with the first uplink beam may be an uplink transmission configuration indicator (TCI) state ID of a TCI state, a spatial relation information ID of spatial relation information, or a spatial reference signal ID within the TCI state or the spatial relation information. The base station may further be configured to apply a second spatial identifier associated with a second uplink beam of the at least one second uplink beam to the uplink signal when the second uplink beam is different than the first uplink beam. In some examples, the first uplink beam is a first uplink transmit beam at the UE forming a first beam pair link with a first uplink receive beam at the base station. The base station may further be configured to form a second beam pair link between a second uplink receive beam at the base station and the first uplink transmit beam when the at least one second uplink beam includes the first uplink transmit beam.

In some examples, the base station may receive the request for the uplink beam refinement within a medium access control (MAC) control element (MAC-CE) of a physical uplink shared channel (PUSCH) . For example, the request may be received within an existing uplink grant for the PUSCH. As another example, the base station may receive a scheduling request for an uplink grant for the PUSCH. In some examples, the base station may receive the request for the uplink beam refinement within uplink control information of a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) . In some examples, the base station may receive the request for the uplink beam refinement within a random access message. For example, the random access message may include a random access channel RACH preamble. As another example, the random access message may include a physical uplink shared channel (PUSCH) payload. The PUSCH payload may include a medium access control (MAC) control element (MAC-CE) including the request for the uplink beam refinement. In some examples, the base station may receive the request for the uplink beam refinement within an uplink radio resource control (RRC) message. For example, the uplink beam refinement circuitry 1646, together with the communication and processing circuitry 1644 and transceiver 1610, shown and described above in connection with FIG. 16 may receive the request for the uplink beam refinement.

At block 1806, the base station may perform the uplink beam refinement based on the at least one beam refinement parameter included in the request. For example, the base station may utilize a downlink beam management scheme or an uplink beam management scheme based on the selected beam management scheme included in the request. In addition, the base station may utilize a beam sweep type and number of reference signal resources for the beam sweep type indicated in the request to perform the uplink beam refinement. For example, the uplink beam refinement circuitry 1646, together with the communication and processing circuitry 1644 and transceiver 1610, shown and described above in connection with FIG. 16 may perform the uplink beam refinement.

At block 1808, the base station may identify at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the UE. For example, when utilizing a downlink beam management scheme, the base station may identify the at least one second uplink beam based on the beam measurements of downlink beam reference signals included in a beam measurement report. As another example, when utilizing an uplink beam management scheme, the base station may select the at least one second uplink beam and notify the UE of the selected second uplink transmit beam (s) . For example, the uplink beam refinement circuitry 1646, together with the communication and processing circuitry 1644 and transceiver 1610, shown and described above in connection with FIG. 16 may identify the at least one second uplink beam.

In one configuration, the base station 1600 includes means for performing the various functions and processes described in relation to FIG. 18. In one aspect, the aforementioned means may be the processor 1604 shown in FIG. 16 configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a circuit or any apparatus configured to perform the functions recited by the aforementioned means.

Of course, in the above examples, the circuitry included in the processor 1604 is merely provided as an example, and other means for carrying out the described functions may be included within various aspects of the present disclosure, including but not limited to the instructions stored in the computer-readable storage medium 1606, or any other suitable apparatus or means described in any one of the FIGs. 1, 2, and/or 4–11, and utilizing, for example, the processes and/or algorithms described herein in relation to FIG. 18.

Several aspects of a wireless communication network have been presented with reference to an exemplary implementation. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures and communication standards.

By way of example, various aspects may be implemented within other systems defined by 3GPP, such as Long-Term Evolution (LTE) , the Evolved Packet System (EPS) , the Universal Mobile Telecommunication System (UMTS) , and/or the Global System for Mobile (GSM) . Various aspects may also be extended to systems defined by the 3rd Generation Partnership Project 2 (3GPP2) , such as CDMA2000 and/or Evolution-Data Optimized (EV-DO) . Other examples may be implemented within systems employing IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Ultra-Wideband (UWB) , Bluetooth, and/or other suitable systems. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean “serving as an example, instance, or illustration. ” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term “aspects” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B, and object B touches object C, then objects A and C may still be considered coupled to one another-even if they do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly physically in contact with the second object. The terms “circuit” and “circuitry” are used broadly, and intended to include both hardware implementations of electrical devices and conductors that, when connected and configured, enable the performance of the functions described in the present disclosure, without limitation as to the type of electronic circuits, as well as software implementations of information and instructions that, when executed by a processor, enable the performance of the functions described in the present disclosure.

One or more of the components, steps, features and/or functions illustrated in FIGs. 1–18 may be rearranged and/or combined into a single component, step, feature or function or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from novel features disclosed herein. The apparatus, devices, and/or components illustrated in FIGs. 1, 2, 4–11, 15, and/or 16 may be configured to perform one or more of the methods, features, or steps described herein. The novel algorithms described herein may also be efficiently implemented in software and/or embedded in hardware.

It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, b, and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

Claims

A method for wireless communication at a user equipment (UE) in a wireless communication network, the method comprising:

communicating with a base station using at least a first uplink beam of a plurality of uplink beams;

transmitting a request for an uplink beam refinement, the request includes at least one beam refinement parameter;

performing the uplink beam refinement based on the at least one beam refinement parameter; and

identifying at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the base station.
The method of claim 1, further comprising:

selecting a selected beam management scheme to utilize for the uplink beam refinement, wherein the selected beam management scheme is an uplink beam management scheme or a downlink beam management scheme,

wherein the at least one beam refinement parameter includes an indication of the selected beam management scheme.
The method of claim 2, further comprising:

selecting a selected beam sweep type selected from a full range beam sweep of at least a plurality of coarse beams, a local beam sweep of a plurality of narrow beams within a selected coarse beam of the plurality of coarse beams, or a beam repetition of a selected narrow beam within the plurality of narrow beams,

wherein the at least one beam refinement parameter further includes an indication of the selected beam sweep type.
The method of claim 3, wherein the at least one beam refinement parameter further includes a number of reference signal resources associated with a reference signal utilized for the selected beam sweep type.
The method of claim 4, wherein the reference signal is a sounding reference signal (SRS) when the selected beam management scheme is the uplink beam management scheme.
The method of claim 4, wherein the reference signal is a synchronization signal block (SSB) or channel state information (CSI) reference signal (CSI-RS) when the selected beam management scheme is the downlink beam management scheme.
The method of claim 1, further comprising:

selecting an uplink transmission scheme to utilize for the at least one second uplink beam,

wherein the at least one beam refinement parameter includes at least one uplink transmission parameter associated with the uplink transmission scheme.
The method of claim 7, wherein the at least one uplink transmission parameter includes a number of the at least one second uplink beam to utilize for transmission of an uplink signal.
The method of claim 8, wherein the at least one uplink transmission parameter further includes a multiplexing scheme for the at least one second uplink beam when the number of the at least one second uplink beam is greater than one.
The method of claim 9, wherein the multiplexing scheme is time division multiplexing, frequency division multiplexing, or spatial division multiplexing.
The method of claim 7, wherein the at least one uplink transmission parameter further includes a number of repetitions of each of the at least one second uplink beam for transmission of an uplink signal.
The method of claim 1, wherein the at least one beam refinement parameter further includes an indication of an uplink signal associated with the at least one second uplink beam, wherein the uplink signal is a physical uplink control channel (PUCCH) , physical uplink shared channel (PUSCH) , a sounding reference signal (SRS) , or a physical random access channel (PRACH) .
The method of claim 12, wherein the indication of the uplink signal is an uplink signal identifier of the uplink signal.
The method of claim 13, wherein the uplink signal identifier is a PUCCH resource identifier (ID) , a SRS resource ID, a SRS resource indicator ID for PUSCH, a PRACH occasion or a preamble ID.
The method of claim 12, wherein the indication of the uplink signal includes a first spatial identifier (ID) associated with the first uplink beam.
The method of claim 15, wherein the first spatial identifier associated with the first uplink beam is an uplink transmission configuration indicator (TCI) state ID of a TCI state, a spatial relation information ID of spatial relation information, or a spatial reference signal ID within the TCI state or the spatial relation information.
The method of claim 16, further comprising:

applying a second spatial identifier associated with a second uplink beam of the at least one second uplink beam to the uplink signal when the second uplink beam is different than the first uplink beam.
The method of claim 15, wherein the first uplink beam is a first uplink transmit beam at the UE forming a first beam pair link with a first uplink receive beam at the base station, and wherein the performing the uplink beam refinement further comprises:

forming a second beam pair link between a second uplink receive beam at the base station and the first uplink transmit beam, wherein the at least one second uplink beam includes the first uplink transmit beam.
The method of claim 18, further comprising:

applying the second uplink receive beam to reception of the uplink signal based on the first spatial identifier associated with the first uplink beam.
The method of claim 1, wherein the transmitting the request for the uplink beam refinement further comprises:

transmitting the request for the uplink beam refinement within a medium access control (MAC) control element (MAC-CE) of a physical uplink shared channel (PUSCH) .
The method of claim 20, wherein transmitting the request for the uplink beam refinement within the MAC-CE of the PUSCH further comprises:

utilizing an existing uplink grant for the PUSCH to transmit the MAC-CE comprising the request for the uplink beam refinement.
The method of claim 20, further comprising:

transmitting a scheduling request for an uplink grant for the PUSCH to transit the MAC-CE including the request for the uplink beam refinement.
The method of claim 1, wherein the transmitting the request for the uplink beam refinement further comprises:

transmitting the request for the uplink beam refinement within uplink control information of a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) .
The method of claim 1, wherein the transmitting the request for the uplink beam refinement further comprises:

transmitting the request for the uplink beam refinement within a random access message.
The method of claim 24, wherein the random access message is a random access channel (RACH) preamble.
The method of claim 24, wherein the random access message includes a physical uplink shared channel (PUSCH) payload, the PUSCH payload including a medium access control (MAC) control element (MAC-CE) including the request for the uplink beam refinement.
The method of claim 1, wherein the transmitting the request for the uplink beam refinement further comprises:

transmitting the request for the uplink beam refinement within an uplink radio resource control (RRC) message.
A method for wireless communication at a base station in a wireless communication network, the method comprising:

communicating with a user equipment (UE) using at least a first uplink beam of a plurality of uplink beams;

receiving a request for an uplink beam refinement, the request includes at least one beam refinement parameter;

performing the uplink beam refinement based on the at least one beam refinement parameter; and

identifying at least one second uplink beam of the plurality of uplink beams selected based on the uplink beam refinement for communication with the UE.
The method of claim 28, wherein the at least one beam refinement parameter includes an indication of a selected beam management scheme, wherein the selected beam management scheme is an uplink beam management scheme or a downlink beam management scheme.
The method of claim 29, wherein the at least one beam refinement parameter further includes an indication of a selected beam sweep type selected from a full range beam sweep of at least a plurality of coarse beams, a local beam sweep of a plurality of narrow beams within a selected coarse beam of the plurality of coarse beams, or a beam repetition of a selected narrow beam within the plurality of narrow beams.
The method of claim 30, wherein the at least one beam refinement parameter further includes a number of reference signal resources associated with a reference signal utilized for the selected beam sweep type.
The method of claim 31, wherein the reference signal is a sounding reference signal (SRS) when the selected beam management scheme is the uplink beam management scheme.
The method of claim 31, wherein the reference signal is a synchronization signal block (SSB) or channel state information (CSI) reference signal (CSI-RS) when the selected beam management scheme is the downlink beam management scheme.
The method of claim 28, wherein the at least one beam refinement parameter includes at least one uplink transmission parameter associated with an uplink transmission scheme to utilize for the at least one second uplink beam.
The method of claim 34, wherein the at least one uplink transmission parameter includes a number of the at least one second uplink beam to utilize for transmission of an uplink signal.
The method of claim 35, wherein the at least one uplink transmission parameter further includes a multiplexing scheme for the at least one second uplink beam when the number of the at least one second uplink beam is greater than one.
The method of claim 36, wherein the multiplexing scheme is time division multiplexing, frequency division multiplexing, or spatial division multiplexing.
The method of claim 34, wherein the at least one uplink transmission parameter further includes a number of repetitions of each of the at least one second uplink beam for transmission of an uplink signal.
The method of claim 28, wherein the at least one beam refinement parameter further includes an indication of an uplink signal associated with the at least one second uplink beam, wherein the uplink signal is a physical uplink control channel (PUCCH) , physical uplink shared channel (PUSCH) , a sounding reference signal (SRS) , or a physical random access channel (PRACH) .
The method of claim 39, wherein the indication of the uplink signal is an uplink signal identifier of the uplink signal.
The method of claim 40, wherein the uplink signal identifier is a PUCCH resource identifier (ID) , a SRS resource ID, a SRS resource indicator ID for PUSCH, a PRACH occasion or a preamble ID.
The method of claim 39, wherein the indication of the uplink signal includes a first spatial identifier (ID) associated with the first uplink beam.
The method of claim 42, wherein the first spatial identifier associated with the first uplink beam is an uplink transmission configuration indicator (TCI) state ID of a TCI state, a spatial relation information ID of spatial relation information, or a spatial reference signal ID within the TCI state or the spatial relation information.
The method of claim 42, further comprising:

applying a second spatial identifier associated with a second uplink beam of the at least one second uplink beam to the uplink signal when the second uplink beam is different than the first uplink beam.
The method of claim 42, wherein the first uplink beam is a first uplink transmit beam at the UE forming a first beam pair link with a first uplink receive beam at the base station, and wherein the performing the uplink beam refinement further comprises:

forming a second beam pair link between a second uplink receive beam at the base station and the first uplink transmit beam, wherein the at least one second uplink beam includes the first uplink transmit beam.
The method of claim 45, further comprising:

applying the second uplink receive beam to reception of the uplink signal based on the first spatial identifier associated with the first uplink beam.
The method of claim 28, wherein the receiving the request for the uplink beam refinement further comprises:

receiving the request for the uplink beam refinement within a medium access control (MAC) control element (MAC-CE) of a physical uplink shared channel (PUSCH) .
The method of claim 47, wherein receiving the request for the uplink beam refinement within the MAC-CE of the PUSCH further comprises:

receiving the request for the uplink beam refinement within an existing uplink grant for the PUSCH.
The method of claim 48, further comprising:

receiving a scheduling request for an uplink grant for the PUSCH.
The method of claim 28, wherein the receiving the request for the uplink beam refinement further comprises:

receiving the request for the uplink beam refinement within uplink control information of a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) .
The method of claim 28, wherein the receiving the request for the uplink beam refinement further comprises:

receiving the request for the uplink beam refinement within a random access message.
The method of claim 51, wherein the random access message is a random access channel (RACH) preamble.
The method of claim 51, wherein the random access message includes a physical uplink shared channel (PUSCH) payload, the PUSCH payload including a medium access control (MAC) control element (MAC-CE) including the request for the uplink beam refinement.
The method of claim 28, wherein the receiving the request for the uplink beam refinement further comprises:

receiving the request for the uplink beam refinement within an uplink radio resource control (RRC) message.
A user equipment (UE) in a wireless communication network, comprising:

a wireless transceiver;

a memory; and

a processor communicatively coupled to the wireless transceiver and the memory, wherein the processor and the memory are configured to implement any feature described in the attached Specification, either individually or in combination with any other feature, in any configuration.
A user equipment (UE) in a wireless communication network, comprising:

means for implementing any feature described in the attached Specification, either individually or in combination with any other feature, in any configuration.
A non-transitory computer-readable medium comprising code for causing a user equipment (UE) in a wireless communication network to implement any feature described in the attached Specification either individually or in combination with any other feature, in any configuration.
A base station in a wireless communication network, comprising:

a wireless transceiver;

a memory; and

a processor communicatively coupled to the wireless transceiver and the memory, wherein the processor and the memory are configured to implement any feature described in the attached Specification, either individually or in combination with any other feature, in any configuration.
A base station in a wireless communication network, comprising:

means for implementing any feature described in the attached Specification, either individually or in combination with any other feature, in any configuration.
A non-transitory computer-readable medium comprising code for causing a base station in a wireless communication network to implement any feature described in the attached Specification either individually or in combination with any other feature, in any configuration.