Methods and devices for transmit beamsweeping with payload data

A wireless device includes a radio frequency transceiver, an antenna array, and one or more processors configured to transmit and receive signals with the radio frequency transceiver and the antenna array, and further configured to transmit, with a first antenna beam, a first plurality of blocks of payload data, transmit, with a second antenna beam, a second plurality of blocks of payload data, receive from a receiver device, feedback on the first plurality of blocks and the second plurality of blocks that requests retransmission or transmit power adjustments, select, based on the feedback, an antenna beam as a transmit antenna beam, and transmit payload data to the receiver device with the transmit antenna beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European Application No. 19 192 046.1 filed on Aug. 16, 2019, which is incorporated by reference in its entirety.

TECHNICAL FIELD

Various aspects relate generally to methods and devices for transmit beamsweeping with payload data.

BACKGROUND

Radio access technologies such as WiGiG and Fifth Generation (5G) New Radio (NR) use beamforming to compensate for the higher pathloss at high frequency carriers. To use beamforming, a device applies different weights to different elements of antenna array. When the device wirelessly transmits with that antenna array, the resulting radio signals form a radiation pattern of constructive and destructive interference. By adjusting the weights, the device may therefore steer its antenna radiation pattern in specific directions, such as in the direction of a target device. Devices can also use beamforming in the receive direction with a similar technique. For example, a device may receive with an antenna array, apply different weights to the signals received by the different elements, and then combine the weighted signals. Depending on the weights at each element, the resulting combined signal will be more sensitive in certain directions around the device. Like in the transmit case, the device can steer its antenna radiation pattern to receive signals in a certain direction.

DESCRIPTION

The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and aspects of aspects in which the disclosure may be practiced.

The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” The words “plurality” and “multiple” in the description and claims refer to a quantity greater than one. The terms “group,” “set”, “sequence,” and the like refer to a quantity equal to or greater than one. Any term expressed in plural form that does not expressly state “plurality” or “multiple” similarly refers to a quantity equal to or greater than one. The term “reduced subset” refers to a subset of a set that contains less than all elements of the set. Any vector and/or matrix notation utilized herein is exemplary in nature and is employed for purposes of explanation. Aspects of this disclosure described with vector and/or matrix notation are not limited to being implemented with vectors and/or matrices and the associated processes and computations may be performed in an equivalent manner with sets or sequences of data or other information.

As used herein, “memory” is understood as a non-transitory computer-readable medium in which data or information can be stored for retrieval. References to “memory” included herein may thus be understood as referring to volatile or non-volatile memory, including random access memory (RAM), read-only memory (ROM), flash memory, solid-state storage, magnetic tape, hard disk drive, optical drive, among others, or any combination thereof. Registers, shift registers, processor registers, data buffers, among others, are also embraced herein by the term memory. The term “software” refers to any type of executable instruction, including firmware.

The term “terminal device” utilized herein refers to user-side devices (both portable and fixed) that can connect to a core network and/or external data networks via a radio access network. “Terminal device” can include any mobile or immobile wireless communication device, including User Equipments (UEs), Mobile Stations (MSs), Stations (STAs), cellular phones, tablets, laptops, personal computers, wearables, multimedia playback and other handheld or body-mounted electronic devices, consumer/home/office/commercial appliances, vehicles, and any other electronic device capable of user-side wireless communications.

The term “network access node” as utilized herein refers to a network-side device that provides a radio access network with which terminal devices can connect and exchange information with a core network and/or external data networks through the network access node. “Network access nodes” can include any type of base station or access point, including macro base stations, micro base stations, NodeBs, evolved NodeBs (eNBs), gNodeBs, Home base stations, Remote Radio Heads (RRHs), relay points, Wi-Fi/WLAN Access Points (APs), Bluetooth master devices, DSRC RSUs, terminal devices acting as network access nodes, and any other electronic device capable of network-side wireless communications, including both immobile and mobile devices (e.g., vehicular network access nodes, moving cells, and other movable network access nodes). As used herein, a “cell” in the context of telecommunications may be understood as a sector served by a network access node. Accordingly, a cell may be a set of geographically co-located antennas that correspond to a particular sectorization of a network access node. A network access node can thus serve one or more cells (or sectors), where the cells are characterized by distinct communication channels.

Various aspects of this disclosure may utilize or be related to radio communication technologies. While some examples may refer to specific radio communication technologies, the examples provided herein may be similarly applied to various other radio communication technologies, both existing and not yet formulated, particularly in cases where such radio communication technologies share similar features as disclosed regarding the following examples. For purposes of this disclosure, radio communication technologies may be classified as one of a Short Range radio communication technology or Cellular Wide Area radio communication technology. Short Range radio communication technologies may include Bluetooth, WLAN (e.g., according to any IEEE 802.11 standard), and other similar radio communication technologies. Cellular Wide Area radio communication technologies may include Global System for Mobile Communications (GSM), Code Division Multiple Access 2000 (CDMA2000), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), General Packet Radio Service (GPRS), Evolution-Data Optimized (EV-DO), Enhanced Data Rates for GSM Evolution (EDGE), High Speed Packet Access (HSPA; including High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), HSDPA Plus (HSDPA+), and HSUPA Plus (HSUPA+)), Worldwide Interoperability for Microwave Access (WiMax), 5G New Radio (NR), for example, and other similar radio communication technologies. Cellular Wide Area radio communication technologies also include “small cells” of such technologies, such as microcells, femtocells, and picocells. Cellular Wide Area radio communication technologies may be generally referred to herein as “cellular” communication technologies.

Unless explicitly specified, the term “transmit” encompasses both direct (point-to-point) and indirect transmission (via one or more intermediary points). Similarly, the term “receive” encompasses both direct and indirect reception. Furthermore, the terms “transmit”, “receive”, “communicate”, and other similar terms encompass both physical transmission (e.g., the wireless transmission of radio signals) and logical transmission (e.g., the transmission of digital data over a logical software-level connection). For example, a processor (or controller or physical layer) may transmit or receive data over a software-level connection with another processor (or controller or physical layer) in the form of radio signals, where the physical transmission and reception is handled by radio-layer components such as RF transceivers and antennas, and the logical transmission and reception over the software-level connection is performed by the processors.

Many wireless communication technologies use beamforming to increase link strength between transmitter and receiver. The Third Generation Partnership Project's (3GPP) Fifth Generation (5G) New Radio (NR) standard, for example, includes mechanisms for beamforming in both the transmit and receive directions. Focusing on the terminal side, a terminal device (e.g., a UE) may identify a receive antenna beam and a transmit antenna beam for a given network access node (e.g., gNodeB). In the receive direction, the terminal device can then increase link strength by receiving signals from the network access node with the receive antenna beam. Similarly, in the transmit direction the terminal device can boost link strength by transmitting signals to the network access node with the transmit antenna beam.

Some terminal device manufacturers initially assumed that terminals could select transmit antenna beams (e.g., for mmWave bands) using beam correspondence. That is, once a terminal device performed beamsweeping to identify a receive antenna beam, it could then use a transmit antenna beam that overlaps spatially with the receive antenna beam—in other words, a transmit antenna beam that corresponded with the receive antenna beam. Assuming uplink and downlink channel reciprocity, the terminal device would not need to perform a dedicated transmit beamsweeping procedure to determine the transmit antenna beam; it could instead directly derive the transmit antenna beam from the receive antenna beam that it already acquired. Because transmit beamsweeping requires extra radio resources (both for beamsweeping and for the network access node to send feedback), beam correspondence can avoid extra radio resource allocation in the network side.

However, despite its benefits, beam correspondence may have drawbacks in practice. In real-world use cases, a terminal device's transmit and receive circuitry will not be ideal. This means a transmit antenna beam may operate differently from a receive antenna beam, even if they are steered in the same direction. For instance, a terminal device's transmit phase shifters may be implemented differently from its receive phase shifters, or its internal design may have other imperfections that lead to differences between the transmit and receive paths. As a result, it can be both challenging and expensive for vendors to design an ideal terminal device that can support full beam correspondence, especially in high frequency bands like 5G mmWave.

Accordingly, when real-world terminal devices operate, their transmit antenna beams may not overlap perfectly with the best receive antenna beam obtained from beamsweeping, even if the transmit and receive antenna beams are theoretically identical. Moreover, when the terminal device transmits with the transmit antenna beam, the equivalent isotropically radiated power (EIRP) may not be optimally focused in the desired direction, leading to sub-optimal uplink performance.

Though 3GPP discussions to date have tried to address these potential issues, the proposed solutions are still not ideal. For instance, 3GPP discussions have proposed that a terminal device can choose to support either full beam correspondence or partial beam correspondence. When operating, a terminal device can indicate its capability to the network. If the terminal device supports full beam correspondence, it is assumed that it can reuse the same receive antenna beam in the transmit direction. As discussed above, it can be very complex and expensive to manufacture devices that meet this criteria.

On the other hand, terminal devices that only support partial beam correspondence may use transmit beamsweeping to meet the beam correspondence accuracy requirements. While these devices may be less complex and expensive, they may use extra network resources and consume additional power. Specifically, the network will schedule specific reference signal resources for the terminal device (e.g., beam management (BM) sounding reference signal (SRS) resources for 5G NR). The terminal device transmits these reference signal resources as scheduled, using different transmitting antenna beams for different reference signal resources. The serving network access node then measures the reference signal resources and reports back to the terminal device which reference signal resources. Based on that feedback, the terminal device can identify which transmit antenna beam produced the strongest radio link and then select that transmit antenna beam for transmitting to the network access node.

Though effective, transmit beamsweeping requires extra radio resources for the reference signals and increases device power consumption. Moreover, like in 3GPP NR, the terminal device may not be able to dynamically trigger transmit beamsweeping. That is, the network may have complete discretion in triggering transmit beamsweeping for the terminal device, and may only allocate reference signal resources (e.g., BM SRS for NR) to the terminal device periodically. As a result, even if the terminal device knows that it should update its transmit antenna beam, it may not be able to trigger transmit beamsweeping on its own. For instance, the terminal device may update its receive antenna beam with receive beamsweeping, which likely means that it should also update its transmit antenna beam. However, since the network will not know when the terminal device's receive antenna beam changes, the network may not immediately trigger transmit beamsweeping. The terminal device may thus not be able to refine its transmit antenna beam using beamsweeping and may be stuck with poor transmit beamforming performance until the network access node eventually triggers transmit beamsweeping.

Recognizing these drawbacks, this disclosure is directed to a beamsweeping technique that uses payload data and receiver feedback to select a transmit antenna beam for a transmitter. For example, a terminal device may transmit to a network access node multiple blocks of payload data using different transmit antenna beams. The network access node may receive the payload data and respond with payload data feedback, such as retransmission information and transmit power adjustment requests. The terminal device can then assess the different transmit antenna beams based on the payload data feedback, such as by evaluating which transmit antenna beams had low retransmission rates or which had few transmit power increase requests. Using this information, the terminal device can then select one of the transmit antenna beams and use that transmit antenna beam to transmit to the network access.

Since the terminal device tests transmit antenna beams on payload data, the terminal device may not need dedicated radio resources for reference signals. This conserves radio resources and enables the terminal device to update its transmit beam without waiting for the network to allocate dedicated radio resources. Similarly, because the terminal device uses existing control resources for the feedback (e.g., ACKs/NACKs and transmit power control (TPC)), the network access node may not need to allocate extra resources to transmit separate beamsweeping feedback. Moreover, the terminal device can avoid the power penalty of performing a standalone transmit beamsweeping procedure.

This disclosure will first discuss general configurations for a network, terminal device, and beamforming, and will follow that with a description of beamsweeping techniques that use payload data.FIGS. 1 and 2depict a general network and device architecture for wireless communications.FIG. 1shows exemplary radio communication network100according to some aspects, which may include terminal devices102and104and network access nodes110and120. Radio communication network100may communicate with terminal devices102and104via network access nodes110and120over a radio access network. Although certain examples described herein may refer to a particular radio access network context (e.g., LTE, UMTS, GSM, other 3rd Generation Partnership Project (3GPP) networks, WLAN/WiFi, Bluetooth, 5G NR, mmWave, WiGig, etc.), these examples are illustrative and may be readily applied to any other type or configuration of radio access network. The number of network access nodes and terminal devices in radio communication network100is exemplary and is scalable to any amount.

In an exemplary cellular context, network access nodes110and120may be base stations (e.g., eNodeBs, NodeBs, Base Transceiver Stations (BTSs), gNodeBs, or any other type of base station), while terminal devices102and104may be cellular terminal devices (e.g., Mobile Stations (MSs), User Equipments (UEs), or any type of cellular terminal device). Network access nodes110and120may therefore interface (e.g., via backhaul interfaces) with a cellular core network such as an Evolved Packet Core (EPC, for LTE), Core Network (CN, for UMTS), or other cellular core networks, which may also be considered part of radio communication network100. The cellular core network may interface with one or more external data networks. In an exemplary short-range context, network access node110and120may be access points (APs, e.g., WLAN or WiFi APs), while terminal device102and104may be short range terminal devices (e.g., stations (STAs)). Network access nodes110and120may interface (e.g., via an internal or external router) with one or more external data networks.

Network access nodes110and120(and, optionally, other network access nodes of radio communication network100not explicitly shown inFIG. 1) may accordingly provide a radio access network to terminal devices102and104(and, optionally, other terminal devices of radio communication network100not explicitly shown inFIG. 1). In an exemplary cellular context, the radio access network provided by network access nodes110and120may enable terminal devices102and104to wirelessly access the core network via radio communications. The core network may provide switching, routing, and transmission, for traffic data related to terminal devices102and104, and may further provide access to various internal data networks (e.g., control nodes, routing nodes that transfer information between other terminal devices on radio communication network100, etc.) and external data networks (e.g., data networks providing voice, text, multimedia (audio, video, image), and other Internet and application data). In an exemplary short-range context, the radio access network provided by network access nodes110and120may provide access to internal data networks (e.g., for transferring data between terminal devices connected to radio communication network100) and external data networks (e.g., data networks providing voice, text, multimedia (audio, video, image), and other Internet and application data).

The radio access network and core network of radio communication network100may be governed by communication protocols that can vary depending on the specifics of radio communication network100. Such communication protocols may define the scheduling, formatting, and routing of both user and control data traffic through radio communication network100, which includes the transmission and reception of such data through both the radio access and core network domains of radio communication network100. Accordingly, terminal devices102and104and network access nodes110and120may follow the defined communication protocols to transmit and receive data over the radio access network domain of radio communication network100, while the core network may follow the defined communication protocols to route data within and outside of the core network. Exemplary communication protocols include LTE, UMTS, GSM, WiMAX, Bluetooth, WiFi, mmWave, 5G NR, and the like, any of which may be applicable to radio communication network100.

FIG. 2shows an exemplary internal configuration of terminal device102according to some aspects, which may include antenna system202, radio frequency (RF) transceiver204, baseband modem206(including digital signal processor208and protocol controller210), application processor212, and memory214. Although not explicitly shown inFIG. 2, in some aspects terminal device102may include one or more additional hardware and/or software components, such as processors/microprocessors, controllers/microcontrollers, other specialty or generic hardware/processors/circuits, peripheral device(s), memory, power supply, external device interface(s), subscriber identity module(s) (SIMs), user input/output devices (display(s), keypad(s), touchscreen(s), speaker(s), external button(s), camera(s), microphone(s), etc.), or other related components.

Terminal device102may transmit and receive radio signals on one or more radio access networks. Baseband modem206may direct such communication functionality of terminal device102according to the communication protocols associated with each radio access network, and may execute control over antenna system202and RF transceiver204to transmit and receive radio signals according to the formatting and scheduling parameters defined by each communication protocol. Although various practical designs may include separate communication components for each supported radio communication technology (e.g., a separate antenna, RF transceiver, digital signal processor, and controller), for purposes of conciseness the configuration of terminal device102shown inFIG. 2depicts only a single instance of such components.

Terminal device102may transmit and receive wireless signals with antenna system202. Antenna system202may be a single antenna or may include one or more antenna arrays that each include multiple antenna elements. For example, antenna system202may include an antenna array at the top of terminal device102and a second antenna array at the bottom of terminal device102. In some aspects, antenna system202may additionally include analog antenna combination and/or beamforming circuitry. In the receive (RX) path, RF transceiver204may receive analog radio frequency signals from antenna system202and perform analog and digital RF front-end processing on the analog radio frequency signals to produce digital baseband samples (e.g., In-Phase/Quadrature (IQ) samples) to provide to baseband modem206. RF transceiver204may include analog and digital reception components including amplifiers (e.g., Low Noise Amplifiers (LNAs)), filters, RF demodulators (e.g., RF IQ demodulators)), and analog-to-digital converters (ADCs), which RF transceiver204may utilize to convert the received radio frequency signals to digital baseband samples. In the transmit (TX) path, RF transceiver204may receive digital baseband samples from baseband modem206and perform analog and digital RF front-end processing on the digital baseband samples to produce analog radio frequency signals to provide to antenna system202for wireless transmission. RF transceiver204may thus include analog and digital transmission components including amplifiers (e.g., Power Amplifiers (PAs), filters, RF modulators (e.g., RF IQ modulators), and digital-to-analog converters (DACs), which RF transceiver204may utilize to mix the digital baseband samples received from baseband modem206and produce the analog radio frequency signals for wireless transmission by antenna system202. In some aspects baseband modem206may control the radio transmission and reception of RF transceiver204, including specifying the transmit and receive radio frequencies for operation of RF transceiver204.

As shown inFIG. 2, baseband modem206may include digital signal processor208, which may perform physical layer (PHY, Layer 1) transmission and reception processing to, in the transmit path, prepare outgoing transmit data provided by protocol controller210for transmission via RF transceiver204, and, in the receive path, prepare incoming received data provided by RF transceiver204for processing by protocol controller210. Digital signal processor208may be configured to perform one or more of error detection, forward error correction encoding/decoding, channel coding and interleaving, channel modulation/demodulation, physical channel mapping, radio measurement and search, frequency and time synchronization, antenna diversity processing, power control and weighting, rate matching/de-matching, retransmission processing, interference cancelation, and any other physical layer processing functions. Digital signal processor208may be structurally realized as hardware components (e.g., as one or more digitally-configured hardware circuits or FPGAs), software-defined components (e.g., one or more processors configured to execute program code defining arithmetic, control, and I/O instructions (e.g., software and/or firmware) stored in a non-transitory computer-readable storage medium), or as a combination of hardware and software components. In some aspects, digital signal processor208may include one or more processors configured to retrieve and execute program code that defines control and processing logic for physical layer processing operations. In some aspects, digital signal processor208may execute processing functions with software via the execution of executable instructions. In some aspects, digital signal processor208may include one or more dedicated hardware circuits (e.g., ASICs, FPGAs, and other hardware) that are digitally configured to specific execute processing functions, where the one or more processors of digital signal processor208may offload certain processing tasks to these dedicated hardware circuits, which are known as hardware accelerators. Exemplary hardware accelerators can include Fast Fourier Transform (FFT) circuits and encoder/decoder circuits. In some aspects, the processor and hardware accelerator components of digital signal processor208may be realized as a coupled integrated circuit.

Terminal device102may be configured to operate according to one or more radio communication technologies. Digital signal processor208may be responsible for lower-layer processing functions (e.g., Layer 1/PHY) of the radio communication technologies, while protocol controller210may be responsible for upper-layer protocol stack functions (e.g., Data Link Layer/Layer 2 and/or Network Layer/Layer 3). Protocol controller210may thus be responsible for controlling the radio communication components of terminal device102(antenna system202, RF transceiver204, and digital signal processor208) in accordance with the communication protocols of each supported radio communication technology, and accordingly may represent the Access Stratum and Non-Access Stratum (NAS) (also encompassing Layer 2 and Layer 3) of each supported radio communication technology. Protocol controller210may be structurally embodied as a protocol processor configured to execute protocol stack software (retrieved from a controller memory) and subsequently control the radio communication components of terminal device102to transmit and receive communication signals in accordance with the corresponding protocol stack control logic defined in the protocol software. Protocol controller210may include one or more processors configured to retrieve and execute program code that defines the upper-layer protocol stack logic for one or more radio communication technologies, which can include Data Link Layer/Layer 2 and Network Layer/Layer 3 functions. Protocol controller210may be configured to perform both user-plane and control-plane functions to facilitate the transfer of application layer data to and from radio terminal device102according to the specific protocols of the supported radio communication technology. User-plane functions can include header compression and encapsulation, security, error checking and correction, channel multiplexing, scheduling and priority, while control-plane functions may include setup and maintenance of radio bearers. The program code retrieved and executed by protocol controller210may include executable instructions that define the logic of such functions.

Terminal device102may also include application processor212and memory214. Application processor212may be a CPU, and may be configured to handle the layers above the protocol stack, including the transport and application layers. Application processor212may be configured to execute various applications and/or programs of terminal device102at an application layer of terminal device102, such as an operating system (OS), a user interface (UI) for supporting user interaction with terminal device102, and/or various user applications. The application processor may interface with baseband modem206and act as a source (in the transmit path) and a sink (in the receive path) for user data, such as voice data, audio/video/image data, messaging data, application data, basic Internet/web access data, etc. In the transmit path, protocol controller210may therefore receive and process outgoing data provided by application processor212according to the layer-specific functions of the protocol stack, and provide the resulting data to digital signal processor208. Digital signal processor208may then perform physical layer processing on the received data to produce digital baseband samples, which digital signal processor may provide to RF transceiver204. RF transceiver204may then process the digital baseband samples to convert the digital baseband samples to analog RF signals, which RF transceiver204may wirelessly transmit via antenna system202. In the receive path, RF transceiver204may receive analog RF signals from antenna system202and process the analog RF signals to obtain digital baseband samples. RF transceiver204may provide the digital baseband samples to digital signal processor208, which may perform physical layer processing on the digital baseband samples. Digital signal processor208may then provide the resulting data to protocol controller210, which may process the resulting data according to the layer-specific functions of the protocol stack and provide the resulting incoming data to application processor212. Application processor212may then handle the incoming data at the application layer, which can include execution of one or more application programs with the data and/or presentation of the data to a user via a user interface.

Memory214may be a memory component of terminal device102, such as a hard drive or another such permanent memory device. Although not explicitly depicted inFIG. 2, the various other components of terminal device102shown inFIG. 2may additionally each include integrated permanent and non-permanent memory components, such as for storing software program code, buffering data, etc.

In accordance with some radio communication networks, terminal devices102and104may execute mobility procedures to connect to, disconnect from, and switch between available network access nodes of the radio access network of radio communication network100. As each network access node of radio communication network100may have a specific coverage area, terminal devices102and104may be configured to select and re-select available network access nodes in order to maintain a strong radio access connection with the radio access network of radio communication network100. For example, terminal device102may establish a radio access connection with network access node110while terminal device104may establish a radio access connection with network access node112. If the current radio access connection degrades, terminal devices102or104may seek a new radio access connection with another network access node of radio communication network100; for example, terminal device104may move from the coverage area of network access node112into the coverage area of network access node110. As a result, the radio access connection with network access node112may degrade, which terminal device104may detect via radio measurements such as signal strength or signal quality measurements of network access node112. Depending on the mobility procedures defined in the appropriate network protocols for radio communication network100, terminal device104may seek a new radio access connection (which may be, for example, triggered at terminal device104or by the radio access network), such as by performing radio measurements on neighboring network access nodes to determine whether any neighboring network access nodes can provide a suitable radio access connection. As terminal device104may have moved into the coverage area of network access node110, terminal device104may identify network access node110(which may be selected by terminal device104or selected by the radio access network) and transfer to a new radio access connection with network access node110. Such mobility procedures, including radio measurements, cell selection/reselection, and handover are established in the various network protocols and may be employed by terminal devices and the radio access network in order to maintain strong radio access connections between each terminal device and the radio access network across any number of different radio access network scenarios.

Continuing toFIG. 3, this figure illustrates exemplary beamforming systems according to some aspects. Many emerging communication technologies use such beamforming to improve communication performance. These techniques operate by adjusting the phase of antennas in an array to produce radiation patterns of constructive and destructive interference. By shaping and steering these radiation patterns, radio communication devices can achieve high beamforming gains, which can in turn improve radio communication reliability and performance. This can be particularly beneficial in radio communication technologies that operate at high frequencies, such as millimeter wave (mmWave) technologies. Because these radio technologies may operate at carrier frequencies of 30 GHz and above, beamforming gains can be extremely helpful in compensating for the high pathloss often experienced at carrier frequencies in these ranges.

Beamforming systems may perform processing in one or both of the baseband and RF domains to shape antenna array beam patterns.FIGS. 3A and 3Bshow two simplified beamforming approaches as deployed for an exemplary four-element antenna array. Although the following description may focus on a beamforming in the transmit direction, the same beamforming techniques can be used to achieve beamforming gains in the receive direction. This includes adjusting the beamforming weights to form a receive antenna beam, receiving signals at each antenna element, applying the beamforming weights to the received signals, and combined the weighted signals to obtain a beamformed signal that is steered according to the receive antenna beam.

FIG. 3Aillustrates a simplified digital baseband beamforming architecture that digitally applies complex beamforming weights (composed of both a gain and phase factor) in the baseband domain. As shown inFIG. 3A, beamforming controller302may receive baseband symbol s and subsequently apply a complex weight vectorBB=[α1α2α3α4]Tto s to generateBBs, where each element αi, i=1, 2, 3, 4 is a complex weight (comprising a gain factor and phase shift). Each resulting element [α1s α2s α3s α4s]TofBBs may be baseband symbol s multiplied by some complex weight αi. Beamforming controller302may then map each element ofBBs to a respective RF chain of RF system304, which may each perform digital to analog conversion (DAC), radio carrier modulation, and amplification on the received weighted symbols before providing the resulting RF symbols to a respective element of antenna array306. Antenna array306may then wirelessly transmit each RF symbol. This exemplary model can also be extended to a multi-layer case where a baseband symbol vector s containing multiple baseband symbols s1, s2, etc., in which case baseband precoding vectorBBmay be expanded to a baseband precoding matrixBBfor application to baseband symbol vector s. In this case, αi, i=1, 2, 3, 4 are row vectors, andBBs=[α1s α2s α3s α4s]T. Thus, after multiplyingBBand s, the overall dimension is the same as the overall dimension at the output of beamforming controller302. The below descriptions thus refer to beamforming controller302asBBand transmit symbol/vector as s for this reason while this model can be extended to further dimensions as explained.

By manipulating the beamforming weights ofBB, beamforming controller302may be able to utilize each of the four antenna elements of antenna array306to produce a steered beam (antenna beamforming pattern) that has greater beam gain than a single antenna element. The radio signals emitted by each element of antenna array306may combine to realize a combined waveform that exhibits a pattern of constructive and destructive interference that varies over distances and direction from antenna array306. Depending on a number of factors (such as antenna array spacing and alignment, radiation patterns, carrier frequency, and the like), the various points of constructive and destructive interference of the combined waveform can create a focused beam lobe that can be “steered” in direction via adjustment of the phase and gain factors αiofBB.FIG. 3Ashows several exemplary steered beams generated by antenna array306, which beamforming controller302may control by adjustingBB. Although only steerable main lobes are depicted in the simplified illustration ofFIG. 3A, beamforming controller302may be able to comprehensively “form” the overall beam pattern including nulls and sidelobes through similar adjustment ofBB.

Beamforming controller302may also perform adaptive beamforming, where beamforming controller302dynamically changes the beamforming weights in order to adjust the direction and strength of the main lobe in addition to nulls and sidelobes. With these adaptive approaches, beamforming controller302can steer the beam in different directions over time, which may be useful to track the location of a moving target point (e.g. a moving receiver or transmitter). In a radio communication context, beamforming controller302may identify the location of a target receiver device308(e.g. the direction or angle of target receiver device308relative to antenna array306) and subsequently adjustBBin order to generate a beam pattern with a main lobe pointing towards target receiver device308, thus improving the array gain at target receiver device308and consequently improving the receiver performance. Through adaptive beamforming, beamforming controller302may be able to dynamically adjust or “steer” the beam pattern as target receiver device308moves in order to continuously provide focused transmissions to target receiver device308(or conversely focused reception).

In some aspects, beamforming controller302may be implemented as a microprocessor. Beamforming controller302therefore may be able to exercise a high degree of control over both gain and phase adjustments ofBBwith digital processing. However, as shown inFIG. 3Afor RF system304and antenna array306, digital beamforming configurations may use a dedicated RF chain for each element of antenna array306(where each RF chain performs radio processing on a separate weighted symbol αis provided by beamforming controller302); i.e. NRF=N where NRFis the number of RF chains and N is the number of antenna elements. Because there may be a complex assortment of circuitry in each RF chain (DAC, amplification, mixing, etc.), these digital beamforming approaches can be expensive and power-inefficient. These issues may be worsened as the involved number of antennas increases, which may be particularly problematic for the massive antenna arrays targeted for next-generation technologies that will include tens or even hundreds of antenna elements.

Contrasting with the beamforming controller architecture ofFIG. 3A,FIG. 3Bshows an RF beamforming approach. As shown inFIG. 3B, beamforming controller302may provide baseband symbol s to RF transceiver304. RF transceiver304may perform RF transmit processing on baseband symbol s and provide the resulting symbol s (e.g., an analog version of s) to each of phase shifters310. For instance, there may be an analog power splitter after RF transceiver304that splits the analog version of s into four signals, and then provides the four signals to phase shifters310. In the receive direction, the analog power is replaced with an adder that combines the four signals from phase shifters310. In the example shown inFIG. 3B, phase shifters310may include four phase shifters310that each apply a respective phase shift β1to β4to s. In some aspects, phase shifters310may be analog RF phase shifters that apply their respective phase shifts in the analog RF domain. Phase shifters310may provide the resulting phase-shifted symbols β1s to β4s to antenna array306. The respective antennas of antenna array306may wirelessly transmit the phase-shifted symbols. Similar to the operation ofFIG. 3A's digital beamformer,FIG. 3B's RF beamformer may realize a specific antenna beamforming pattern by selecting the phase weights β1to β4. Accordingly, beamforming controller302may be configured to select phase weights β1to β4, such as based on the direction of target receiver device308, and provide the phase weights to β1to β4to phase shifters310(with the “Control” line shown inFIG. 3B). Beamforming controller302may therefore steer the main antenna beam towards target receiver device308through proper selection of the phase weights β1to β4. In some cases, the phase weights may be phase-only (e.g., only a phase shift with no amplitude change); in other aspects, the phase weights may have a phase and a gain component (e.g., a phase shift and an amplitude gain).

As introduced above, transmitters like terminal devices may use this disclosure's beamsweeping techniques to beamsweep using payload data.FIG. 4shows an example according to some aspects. AsFIG. 4shows, terminal device102may transmit and receive signals with network access node110. Terminal device102may use transmit and receive beamforming to increase the radio link strength with network access node110. Looking first at receive beamforming, terminal device102may perform a receive beamsweeping procedure to select a receive antenna beam to use for receiving signals from network access node110. For instance, network access node110may schedule certain radio resources as downlink beamsweeping reference signals (e.g., demodulation reference signals (DMRS) or channel state information reference signals (CSI-RS)). During each of those scheduled radio resources, network access node110may transmit a reference signal burst to terminal device102. Terminal device102may adjust its antenna array202to receive the reference signal bursts with different receive antenna beams. Terminal device102may perform a radio measurement (e.g., with a measurement engine in digital signal processor208) on the reference signal bursts to obtain a radio measurement for each the receive antenna beams. Using those radio measurements, terminal device102may identify the receive antenna beam that yields the best radio link (e.g., strongest radio link) and may then use that receive antenna beam to receive signals from network access node110. Terminal device102may update the receive antenna beam over time, such as with a fixed period or when terminal device102changes its positioning.

As discussed above, some schemes for transmit beamforming may use a dedicated transmit beamsweeping procedure. In those procedures, network access node110may allocate dedicated radio resources during which terminal device102transmits its own reference signal bursts (e.g., sounding reference signals (SRS) for 5G NR). Like the receive beamsweeping case, terminal device102may transmit the reference signal bursts with different transmit antenna beams. That is, terminal device102may adjust antenna array202to use different transmit antenna beams during the reference signal bursts. Network access node110may receive and measure the reference signal bursts to obtain a radio measurement for each. Network access node110may then send dedicated beamsweeping feedback (e.g., with additional radio resources) to terminal device102that indicates which reference signal burst produced the best radio measurement (e.g., highest signal strength). Terminal device102may identify the transmit antenna beam that maps to the indicated reference signal burst and may then use that transmit antenna beam to transmit to network access node110.

As previously discussed, however, these dedicated transmit beamsweeping procedures may require extra radio resources, drain battery, and prevent the terminal device from quickly selecting new transmit antenna beams. Thus, terminal device102may use a specialized transmit beamsweeping procedure to select the transmit antenna beam. In one example, terminal device102may first select a new receive antenna beam, such as with the receive antenna beamsweeping procedure described above. Since terminal device102is using a new receive antenna beam, it is likely that terminal device102should also update its transmit antenna beam. Accordingly, terminal device102may identify a plurality of candidate transmit antenna beams to evaluate for the new transmit antenna beam. In some cases, terminal device102may use the new receive antenna beam as a starting point, such as by selecting, as the candidate transmit antenna beams, transmit beams that point in similar directions to the new receive antenna beam.

Terminal device102may then evaluate the plurality of candidate transmit antenna beams by transmitting payload data with each. Thus, instead of evaluating transmit antenna beams by transmitting reference signals, terminal device102may transmit actual payload data. As used herein, payload data refers to user-plane or control-plane data that carries information bits. Payload data differentiates from reference signals (including synchronization signals), which do not carry a message but instead only represent a predefined signal sequence. As non-limiting examples, payload data can include physical uplink shared channel (PUSCH) data or physical uplink control channel (PUCCH) data. To test the plurality of candidate transmit antenna beams, terminal device102may transmit multiple blocks of payload data for each candidate transmit antenna beam. When it transmits the blocks of payload data, terminal device102may use the radio resources that network access node110allocates for payload data; thus, this technique may not use additional radio resources that are dedicated to beamsweeping procedures.

Network access node110may then receive the payload data. The beamsweeping by terminal device102may be transparent to network access node102. In other words, network access node110may not be aware that terminal device102is testing different candidate transmit antenna beams with the payload data. Since the payload data was scheduled on normal radio resources, to network access node110it may appear that terminal device102is transmitting payload data in a normal fashion. Thus, network access node110may receive and process the payload data as it normally handles payload data. This can include, for example, decoding and demodulating the payload data and perform layer-specific processing on the payload according to the various layers of the communication protocol.

Network access node110may then provide retransmission and/or power control feedback to terminal device102. For retransmission feedback, network access node110may check whether it can successfully decode each block of payload data, such as with a cyclic redundancy check (CRC) or other type of check that evaluates decoding success. If network access node110cannot successfully decode a block of payload data, network access node110transmits a retransmission request to terminal device102. This retransmission request asks terminal device102to retransmit the block of payload data, and may be a non-acknowledgement (NACK) message. On the other hand, if network access node110successfully decodes a block of payload data, network access node110may not transmit a NACK. Depending on the standard, network access node110may send to terminal device110a positive acknowledgement (ACK) that affirms successful receipt of the block of payload data.

For power control feedback, network access node110may evaluate signals it receives from terminal device102and may determine whether terminal device102should increase or decrease its transmit power. For instance, if network access node110receives signals from terminal device102with very low receive power (e.g., a received signal power that is lower than a decoding sensitivity requirement), network access node110may send a transmit power adjustment (e.g., transmit power control (TPC) command, carried by the physical downlink control channel (PDCCH) in LTE and 5G NR) that instructs terminal device102to increase its uplink transmit power. Conversely, if network access node110receives signal from terminal device102excessive receive power, network access node110may send a transmit power adjustment that instructs terminal device to decrease its uplink transmit power.

Network access node110may be configured to send retransmission and power control feedback whenever terminal device102sends payload data. Thus, network access node110may provide this feedback no matter whether terminal device102is beamsweeping or not. Unlike the feedback for dedicated transmit beamsweeping, this feedback does not use extra dedicated radio resources.

Terminal device102may then use network access node102's retransmission and power control feedback to evaluate the plurality of candidate transmit antenna beams. For instance, terminal device102may determine the retransmission rate (e.g., ratio of NACKs to ACKs) for each candidate transmit antenna beam based on the retransmission feedback for the blocks of payload data for the respective candidate transmit antenna beam. Based on retransmission rate, the best candidate antenna beams are those with low retransmission rates (e.g., significantly more ACKs than NACKs). For power control feedback, terminal device102may determine whether any of the candidate transmit antenna beams caused network access node110to request transmit decreases. If so, terminal device102may consider those candidate transmit antenna beams poor choices for the transmit antenna beam.

UsingFIG. 4as an example, terminal device102may use the five shown transmit antenna beams as the plurality of candidate transmit antenna beams. Some may point more directly to network access node110than others. For instance, the outermost candidate transmit antenna beams may not point in the direction of network access node110while the inner candidate transmit antenna beams may point closer to network access node110. As explained above, terminal device102may send multiple blocks of payload data with each of the plurality of candidate transmit antenna beams, and may evaluate the resulting feedback from network access node110to select one as the transmit antenna beam.

Because the outermost candidate transmit antenna beams do not point directly at network access node110, these candidate transmit antenna beams are likely to produce the worst feedback from network access node110. For instance, when terminal device102transmits blocks of payload data with one of the outermost candidate transmit antenna beams, antenna array102may propagate the wireless signals in a different direction than network access node110. As a result, network access node110may receive the wireless signals (containing the blocks of payload data) with lower received signal power than the inner candidate transmit antenna beams. Because the received signal power is low, the wireless signal may be more susceptible to noise and interference, and network access node110may not be able to decode one or more of the blocks of payload data. Thus, network access node110may transmit a high rate of NACKs for the blocks of payload data for this outermost candidate transmit antenna beam. Based on that retransmission feedback, terminal device102may conclude that this outermost candidate transmit antenna beam has a high retransmission rate and is thus a poor choice for the transmit antenna beam.

The power control feedback may similarly indicate that this outermost candidate transmit antenna beam is a poor choice. Because it is not pointed directly toward network access node110, network access node110may determine that the wireless signals (carrying the blocks of payload data for this outermost candidate transmit antenna beam) have low received signal power. To counteract the low received signal power, network access node110may send power control feedback that instructs terminal device102to increase its transmit power. Accordingly, terminal device102may determine that this outermost candidate transmit antenna beam is received with low signal power at network access node110, meaning that it is a poor choice for the transmit antenna beam.

FIG. 5shows an exemplary internal configuration of terminal device102according to some aspects. While this depiction includes many of the same subcomponents ofFIG. 2,FIG. 3's depiction is focused on terminal device102's selection of roaming mobile networks. It therefore omits other subcomponents that are less directly related to those capabilities. As shown inFIG. 5, terminal device102may include antenna array502, RF transceiver504, and baseband modem506, which may be configured in the manner described above for terminal device102inFIG. 2. Accordingly, baseband modem506may direct communication operations of terminal device102according to the communication protocols for each radio access network, and may control antenna array502and RF transceiver504to transmit and receive radio signals according to the formatting and scheduling parameters defined by each communication protocol.

AsFIG. 5shows, terminal device102may include antenna array502, RF transceiver504, and baseband processor506. Terminal device102may transmit and receive radio signals on one or more radio access networks. Baseband processor506may direct that communication functionality of terminal device102according to the communication protocols for each radio access network, and may control antenna array502and RF transceiver504to transmit and receive radio signals according to the formatting and scheduling parameters defined by each communication protocol.

Terminal device102may transmit and receive wireless signals with antenna array502, which may be an antenna array that includes multiple antenna elements. In some aspects, antenna array502may include analog antenna combination and/or beamforming circuitry (e.g., a set of phase shifters for phased-array beamforming). In the receive (RX) path, RF transceiver504may receive analog radio frequency signals from antenna array502and perform analog and digital RF front-end processing on the analog radio frequency signals to produce digital baseband samples (e.g., In-Phase/Quadrature (IQ) samples) to provide to baseband processor506. RF transceiver504may include analog and digital reception components including amplifiers (e.g., Low Noise Amplifiers (LNAs)), filters, RF demodulators (e.g., RF IQ demodulators)), and analog-to-digital converters (ADCs), which RF transceiver504may utilize to convert the received radio frequency signals to digital baseband samples. In the transmit (TX) path, RF transceiver504may receive digital baseband samples from baseband processor506and perform analog and digital RF front-end processing on the digital baseband samples to produce analog radio frequency signals to provide to antenna array502for wireless transmission. RF transceiver504may thus include analog and digital transmission components including amplifiers (e.g., Power Amplifiers (PAs), filters, RF modulators (e.g., RF IQ modulators), and digital-to-analog converters (DACs), which RF transceiver504may utilize to mix the digital baseband samples received from baseband processor506and produce the analog radio frequency signals for wireless transmission by antenna array502. In some aspects baseband processor506may control the radio transmission and reception of RF transceiver504, including specifying the transmit and receive radio frequencies for operation of RF transceiver504.

FIG. 5also depicts several internal components of baseband processor506, including digital receiver508, digital transmitter510, and controller512. In some aspects, baseband processor506may include a digital signal processor and a protocol controller (e.g., such as inFIG. 2). Digital receiver508, digital transmitter510, and controller512may therefore be subcomponents of the digital signal processor (e.g., physical layer components) and/or subcomponents of the protocol controller (e.g., protocol stack components). In some aspects, digital receiver508may be the physical layer receive chain, digital transmitter510may be the physical layer transmit chain, and controller512may be the protocol controller that executes the protocol stack of baseband processor506. For example, digital receiver508may include a demodulator, demapper (e.g., constellation demapper), de-interleaver, decoder, and/or descrambler. Digital receiver508may receive wireless signals in the form of baseband samples via antenna array502and RF transceiver504. Digital receiver508may then sequentially process these baseband samples with the demodulator, demapper (e.g., constellation demapper), de-interleaver, decoder, and/or descrambler to produce a bitstream, which digital receiver508may provide to controller512(e.g., to protocol stack layers of controller512). Digital transmitter510may include a scrambler, encoder, interleaver, mapper (e.g., constellation mapper), and/or a modulator, which may sequentially process a bitstream (e.g., provided by protocol stack layers of controller512) to produce baseband samples (e.g., complex IQ symbols). Digital transmitter510may then transmit these baseband samples as wireless signals via RF transceiver504and antenna array502. Controller512may include one or more processors configured to execute the protocol stack layers as software. This may include generating messages for digital transmitter510to transmit (e.g., messages including user or control data) and/or recovering messages from bitstreams provided by digital receiver508. In some aspects, controller512may be configured to perform user-plane and control-plane functions to facilitate the transfer of application layer data to and from terminal device102according to the specific protocols of the supported radio communication technology. User-plane functions can include header compression and encapsulation, security, error checking and correction, channel multiplexing, scheduling and priority, while control-plane functions may include setup and maintenance of radio bearers. The program code retrieved and executed by controller512may include executable instructions that define the logic of these functions.

Controller512may also be configured to control beamforming by antenna array502. In some aspects, controller512may be configured with the features of beamforming controller302inFIGS. 3A and 3Band may control the digital or RF beamforming of antenna array502. Controller512may therefore select the beamforming weight vector for antenna array502(either to apply digitally as inFIG. 3Aor with RF phase shifters as inFIG. 3B).

In some aspects, terminal device102may be configured to perform this disclosure's beamsweeping technique by executing exemplary flow chart600shown inFIG. 6. As shown inFIG. 6, terminal device102may first detect an antenna position change in stage602. For instance, controller512may initially control the beamforming circuitry in antenna array502to receive with a first receive antenna pattern. That is, controller512may have previously identified a set of beamforming weights that produce the first receive antenna pattern, and may control phase shifters in antenna array502to shift received signals with the set of beamforming weights. However, controller512may eventually detect that this first receive antenna pattern is outdated in stage602. This can happen, for example, when a user moves or rotates terminal device102so the first receive antenna pattern is not spatially oriented toward network access node110. In some aspects, controller512may detect this change based on downlink beam measurements (e.g., where digital receiver508performs a radio measurement on reference signals from network access node110and controller512determines the radio measurement is less than a predefined threshold), or based on a sensor (e.g., where terminal device102includes one or more sensors that detect motion). In any case, controller512may detect the change and determine that terminal device102should update its receive antenna beam.

After detecting the change, controller512may update the receive antenna beam in stage604. For example, controller512may perform receive beamsweeping to select an updated receive antenna pattern that is oriented toward network access node110. As explained above, for receive beamsweeping network access node110may periodically transmit reference signals (e.g., BM SRS or CSI-RS for 5G NR). Controller512may know in advance which radio resources carry these reference signals. Controller512may control antenna array502's beamforming circuitry to receive the reference signals with each of a plurality of candidate receive antenna beams. Digital receiver508may receive the weighted signals via antenna array502and RF transceiver504, and may perform radio measurements to obtain radio measurements for each of the plurality of candidate receive antenna beams. Depending on how suitable each candidate receive antenna beam is, certain radio measurements will be higher than others (e.g., higher signal strength). Digital receiver508may provide these radio measurements to controller512. Controller512may then select an updated receive antenna beam (e.g., different from the first receive antenna beam) from the plurality of candidate receive antenna beams based on the radio measurements. In one example, controller512may identify the radio measurement with the highest value (e.g., the highest signal strength), identify the candidate receive antenna pattern that produced that radio measurement (e.g., the receive antenna pattern to which antenna array502's beamforming circuitry was set when the radio measurement was produced), and select that candidate receive antenna pattern as the updated receive antenna beam.

Thus, with stage604controller512may update the receive antenna beam. In many scenarios, updating the receive antenna beam indicates that the transmit antenna beam should also be updated. For instance, if a user moves or rotates terminal device102so its receive antenna beam is suboptimal, it is likely that the transmit antenna beam is also now suboptimal. Controller512may therefore also attempt to update its transmit antenna beam (e.g., the transmit antenna beam to which controller512has currently set antenna array502's beamforming circuitry).

After updating the receive antenna beam, controller512may select a plurality of candidate transmit antenna beams based on the updated receive antenna beam in stage606. For example, as explained forFIG. 4, the updated receive antenna beam may be a useful starting point when trying to update the transmit antenna beam. That is, although the optimal transmit antenna beam may not always perfectly overlap with the optimal receive antenna beam, the optimal transmit and receive antenna beams are likely to be close together. As such, controller512may use the updated receive antenna beam to select the plurality of candidate transmit antenna beams.

For instance, in some aspects controller512may have a predefined set of transmit antenna beams, each mapped to a different angular direction and defined by a respective set of beamforming weights. The collection of sets of beamforming weights can form a beamforming codebook, with each set of beamforming weights acting as the codeword for its corresponding transmit antenna beam. After controller512selects the updated receive beam, it may therefore identify the angular direction to which the updated receive beam maps (e.g., the angular direction in which the updated receive beam's main lobe points). Controller512may then identify a plurality of transmit antenna beams that map to similar angular directions, such as by identifying a predefined number of transmit antenna beams that map to the closest angular directions to the updated receive antenna beam. Controller512may select these as the plurality of candidate transmit antenna beams in stage606.

UsingFIG. 4as an example of this, controller512may identify the innermost antenna beam as the updated receive antenna beam, which maps to a particular angular direction. Controller512may then identify, for example, five transmit antenna beams that map to the closest angular directions to the updated receive antenna beam. Of the plurality of predefined transmit antenna beams, one may map to the same angular direction as the updated receive antenna beam, two more may map to the closest angular directions to the updated receive antenna beam, and the outermost transmit antenna beams may map to the second-closest angular directions to the updated receive beam. As these five predefined transmit antenna beams map to the closest angular directions to the updated receive antenna beam, controller512may select them as the plurality of candidate transmit antenna beams in stage606.

In some aspects, controller512may identify the plurality of candidate transmit antenna beams based on a predefined table that maps receive antenna beams to candidate transmit antenna beams. For instance, the predefined table may be developed offline, and may map receive antenna beam to candidate transmit antenna beams based on which candidate transmit antenna beams correspond spatially to different receive antenna beams. As explained previously, the spatial correspondence between receive and transmit antenna beams may depend on factors like receive and transmit phase shifter circuitry and other device design parameters. In some aspects, the predefined table may be developed based on lab RF measurements or factory RF calibrations, which may take those factors into account.

Continuing with flow chart600, controller512may then evaluate the plurality of candidate transmit antenna beams with transmit beamsweeping. In some aspects, controller512may first determine whether dedicated transmit beamsweeping is possible; in other aspects, controller512may not consider dedicated transmit beamsweeping and may instead perform transmit beamsweeping with payload data. In flow chart600's example, controller512may first consider dedicated transmit beamsweeping. Thus, controller512may determine whether beamsweeping reference signal bursts are available in stage608. For example, as previously explained, network access node110may be responsible for triggering dedicated transmit beamsweeping (where it allocates reference signal resources for terminal device102to transmit), and terminal device102may have little or no control over its timing. However, it is still possible that network access node110has already, or will soon, trigger dedicated beamsweeping. Controller512may therefore check in stage608whether network access node110has scheduled transmit beamsweeping reference signal bursts for terminal device102(e.g., whether it has received from network access node110a grant to transmit beamsweeping reference signals), or whether network access node110is expected to soon schedule transmit beamsweeping reference signal bursts for terminal device102(e.g., if network access node110periodically triggers dedicated transmit beamsweeping and the next instance is in the near future). Controller512may have access to scheduling information for terminal device102, and may therefore check the scheduling information in stage608to determine whether dedicated transmit beamsweeping has been or soon will be scheduled.

If controller512determines that beamsweeping reference signal bursts are available in stage608, controller512may perform dedicated transmit beamsweeping in stage610. As explained above, network access node110may allocate transmit reference signal bursts to terminal device102, such as by scheduling radio resources during which terminal device102transmits reference signal bursts. Controller512may then transmit the reference signal bursts with different transmit antenna beams from the plurality of candidate transmit antenna beams (e.g., one or more reference signal bursts for each of the plurality of candidate transmit antenna beams). For instance, controller512may instruct digital transmitter510to transmit the reference signal bursts during the scheduled times, and digital transmitter510may generate and transmit the reference signal bursts vis RF transceiver504and antenna array502. Network access node110may receive and measure the reference signal bursts and may identify which reference signal bursts produced the best measurement (e.g., highest signal strength). Network access node110may then send dedicated beamsweeping feedback to terminal device102that identifies the best reference signal burst. Digital receiver508may receive the dedicated beamsweeping feedback (via antenna array502and RF transceiver504) and may provide it to controller512. Controller512may identify which candidate transmit antenna beam maps to the best reference signal burst reported in the feedback and then select that candidate transmit antenna beam as the transmit antenna beam. Controller512may then control antenna array502's beamforming circuitry to set to the beamforming weights for that transmit antenna beam, and terminal device102may transmit signals to network access node110with the transmit antenna beam.

Conversely, if controller512determines in stage608that transmit beamsweeping reference signal bursts are not available, controller512may perform transmit beamsweeping with payload data. As noted above, in some aspects, controller512may skip stage608, and may perform transmit beamsweeping with payload data without considering dedicated transmit beamsweeping. In either case, controller512may proceed to stage612. In that stage, controller512may transmit blocks of payload data using the plurality of candidate transmit antenna beams. As previously explained, this payload data is different from reference signal bursts. While reference signals bursts only carry predefined signal sequences, payload data includes information bits, such as user-plane or control-plane data. Thus, instead of beamsweeping reference signal bursts, terminal device102may beamsweep with payload data.

In some aspects, controller512may identify an overall pool of blocks of payload data that terminal device102is scheduled to transmit. Controller512may then assign multiple blocks from the overall pool to different candidate transmit antenna beams, e.g., so each of the plurality of candidate transmit antenna beams is mapped to a different set of blocks of payload data. To sweep the candidate transmit antenna beams, controller512may then transmit each set of multiple blocks with the respectively mapped candidate transmit antenna beams. That is, when a given block of payload data is scheduled for transmission, controller512may control antenna array502's beamforming circuitry to set to the beamforming weights for the mapped candidate transmit antenna beam. Digital transmitter510may then transmit the block of payload data via RF transceiver504and antenna array502.

FIGS. 7A and 7Bshows examples of how controller512can allocate an overall pool of blocks of payload data to the plurality of candidate transmit antenna beams according to some aspects. In these simplified examples, controller512may allocate an overall pool of 12 blocks between three candidate transmit antenna beams (beams1-3). For instance, inFIG. 7Acontroller512may alternate, or interleave, the overall pool of blocks of payload data between the candidate transmit antenna beams. This produces a round-robin pattern, where the blocks are allocated to beam1, beam2, beam3, beam1, beam2, beam3, beam1, and so on. This pattern is exemplary, and countless other patterns can be used. In the depicted example, controller512allocates each block of the overall pool to a candidate transmit antenna beams. In other example, controller512may “skip” allocating some blocks to candidate transmit antenna beams, such as where controller512allocates every other block to a candidate transmit antenna beam, or any similar pattern.FIG. 7Bshows another example where controller512may allocate contiguous sets of blocks to each candidate transmit antenna beams. As shown, controller512may allocate blocks1-4to beam1, blocks5-8to beam2, and blocks9-12to beam3.

Once controller512assigns blocks of payload data to candidate transmit antenna beams, controller512may transmit the blocks of payload data to network access node110in stage612. For instance, controller512may provide the blocks of payload data to digital transmitter510, which may then transmit the blocks of payload data in their assigned radio resources. Controller512may then control antenna array502's beamforming circuitry to set to the candidate transmit antenna beam assigned to each block of payload data.

With this procedure, terminal device102may beamsweep with payload data. Network access node110may receive the wireless signals that carry the blocks of payload data (e.g., on the scheduled radio resources) and then process the wireless signals to recover and decode the blocks of payload data. Depending on the communication standard, network access node110may generate feedback on the payload data and transmit the feedback to terminal device102. As introduced above, this feedback can be retransmission feedback and/or power control feedback. These types of feedback are payload feedback and differ from beamsweeping feedback (e.g., beamsweeping feedback that identifies a reference signal burst as being best for beamsweeping).

In stage614, terminal device102may observe the retransmission or power control feedback from network access node110. Terminal device102may then select a transmit antenna beam based on the feedback in stage616. For cases where terminal device102uses retransmission feedback, network access node110may be configured to attempt to decode the blocks of payload data and determine whether the decoding is successful. For example, digital transmitter510may generate an error check field for each block of payload data, such as a cyclic redundancy check (CRC) or other type of error check. Digital transmitter510may include this error check field in each block of payload data. When network access node110receives the block of payload data and attempts to decode it, network access node110may attempt to re-generate the error check field based on the decoded data. If the regenerated error check field matches the error check field in the block of payload data, network access node110may conclude the decode was successful. If the regenerated error check field does not match the error check field in the block of payload data, network access node110may conclude the decode was not successful. In that case, network access node110may send to terminal device a retransmission request that request retransmission of that block of payload data. This retransmission request may be a NACK. In some cases, network access node110may also send an ACK when the decode is successful; in other cases, terminal device102may assume the decode was successful if it does not receive any retransmission feedback.

Digital transmitter510may receive this retransmission feedback (via antenna array502and RF transceiver504) and provide it to controller512. Controller512may collect the retransmission feedback for the blocks of payload data for which it beamswept (e.g., those of the overall pool that it assigned to candidate transmit antenna beams). Controller512may then select a transmit antenna beam based on the transmission feedback in stage616. In one example, controller512may determine, based on the retransmission feedback, a retransmission rate for each of the plurality of candidate transmit antenna beams. This retransmission rate for a candidate transmit antenna beam can be any metric that indicates the number of successful and unsuccessful transmissions of blocks of payload data for that candidate transmit antenna beam. For instance, controller512may determine, for each candidate transmit antenna beam, the number of blocks of payload data (transmitted with the candidate transmit antenna beam) that were successfully transmitted (e.g., that prompted an ACK or no response) and the number of blocks of payload data that were not successfully transmitted (e.g., that prompted a NACK). Controller512may then determine the retransmission rate as the ratio of unsuccessful to total transmissions (or, alternatively, as the ratio of unsuccessful to successful transmissions). This retransmission rate can be expressed, in some examples, as a percentage, such as a 10% retransmission rate that indicates one unsuccessfully transmitted block of payload data out of every 10 total transmitted blocks of payload data.

In some aspects, controller512may determine such a retransmission rate for each of the plurality of candidate transmit antenna beams. This can be part of stage614. Controller512may then select one of the candidate transmit antenna beams based on the retransmission rates in stage616. For instance, controller512may identify which candidate transmit antenna beam has the lowest retransmission rate (e.g., most successful transmissions to unsuccessful transmissions), and then select that candidate transmit antenna beam to use as a transmit antenna beam. After selecting the transmit antenna beam, controller512may control antenna array502's beamforming circuitry to set the beamforming weights to the transmit antenna beam. Digital transmitter510may then transmit signals to network access node100(e.g., that carry additional payload data) via RF transceiver504and antenna array502. Because antenna array502is set to the transmit antenna beam, terminal device102may transmit signals to network access node110with the transmit antenna beam.

When using retransmission rate to select the transmit antenna beam, controller512may therefore determine feedback statistics for each of the plurality of candidate transmit antenna beams. Controller512may then select a transmit antenna beam based on the feedback statistics. As described above, in some aspects controller512may transmit multiple blocks of payload data for each candidate transmit antenna beam, and then receive multiple feedback messages (e.g., NACKs and, optionally, ACKs) for each candidate transmit antenna beam. Controller512may then use the feedback messages for a given candidate transmit antenna beam to determine feedback statistics (e.g., retransmission rate) for that candidate transmit antenna beam. In some cases, controller512may obtain more accurate feedback statistics by transmitting more blocks of payload data for each candidate transmit antenna beam. There may be, however, a tradeoff between feedback statistic accuracy and latency, since transmitting a higher number of blocks of payload data for each candidate transmit antenna beam may take a longer amount of time.

That description covered cases where terminal device102uses retransmission feedback to select the transmit antenna beam. Additionally or alternatively, terminal device102may observe power control feedback in stage614and then select the transmit antenna beam in stage616based on the power control feedback. For instance, network access node110may be configured to send power control feedback to terminal device102that instructs it to increase or decrease its uplink transmit power. To take one example, if network access node110determines that it receives terminal device102's transmissions with very low power, network access node110may send to terminal device102power control feedback (e.g. a message) that instructs terminal device102to increase its uplink transmit power. Conversely, if network access node110determines that it receives terminal device102's transmissions with excessively high power, network access node110may send to terminal device102power control feedback (e.g. a message) that instructs terminal device102to decrease its uplink transmit power. This type of power control feedback is termed transmit power control (TPC) in some 3GPP standards.

In some cases, the power control feedback may indicate a power adjustment, meaning a power increase or a power decrease by which terminal device102should adjust its power. In some aspects, the power control feedback may explicitly indicate a power adjustment (e.g., an explicit field that identifies a power increase or power decrease). In some aspects, the power control feedback may implicitly indicate a power adjustment, such as where the power control feedback explicitly identifies an updated transmit power (where the power adjustment is the difference between the current and updated transmit powers) or where the power control feedback identifies a predefined power increase or predefined power decrease.

When it transmits the blocks of payload data for the candidate transmit antenna beams in stage612, controller512may therefore receive and record the power control feedback from network access node110. For example, digital transmitter510may transmit (via RF transceiver504and antenna array502) the blocks of payload data for each of the plurality of candidate beams in stage612. Digital transmitter510may transmit with a current transmit power, such as the transmit power that network access node110previously assigned to terminal device102.

Network access node110may receive the blocks of payload data and decide whether to instruct terminal device102to increase, decrease, or maintain its current transmit power. If network access node110decides to increase terminal device102's transmit power, it may send power control feedback that instructs terminal device102to increase its transmit power by a positive power adjustment. Conversely, if network access node110decides to decrease terminal device102's transmit power, it may send power control feedback that instructs terminal device102to decrease its transmit power by a negative power adjustment. If network access node110decides to maintain terminal device102's transmit power, it may not send any power control feedback.

Terminal device102may then observe the power control feedback connected to the blocks of payload data for each candidate transmit antenna beam in stage614. Then, terminal device102may select a transmit antenna beam based on the power control feedback in stage616. For instance, terminal device102may select the transmit antenna beam based on which candidate transmit antenna beams triggered few or no positive power adjustments. When network access node110transmits power control feedback with a positive power adjustment, it likely means that network access node110received the signal with low signal power. Thus, positive power adjustments can indicate that terminal device102's transmit antenna beam is not steered in the right direction. Thus, when terminal device102transmits a block of payload data with a candidate transmit beam that is steered in the wrong direction, there is a higher chance that network access node110will respond with power control feedback that requests a positive power adjustment. On the other hand, when terminal device102transmits a block of payload data with a candidate transmit beam that is steered directly toward network access node110, there is a higher chance that network access node110will not respond with any power control feedback (e.g., maintain terminal device102's current transmit power), or will respond with power control feedback that requests a negative power adjustment.

In other words, positive power adjustments may indicate that a candidate transmit antenna beam is a poor choice, while negative or no power adjustments may indicate that a candidate transmit beam is a suitable choice. Controller512may therefore observe the power control feedback for each candidate transmit power beam and identify which candidate transmit power beams trigger few or no positive power adjustments. For instance, network access node110may send power control feedback in response to signals that terminal device102recently transmitted. Controller512may therefore observe the power control feedback in response to the blocks of payload data, and observe the power control feedback for each of the plurality of candidate transmit antenna beams (mapped to specific blocks of payload data). That is, controller512may record whether each candidate transmit antenna beam prompts positive, negative, or no power adjustments from network access node110.

Controller512may then select the transmit antenna beam based on the number of positive and negative power adjustments prompted by the different candidate transmit antenna beams. In one example, controller512may identify which candidate transmit antenna beam prompts the fewest positive power adjustments, and select that candidate transmit antenna beam as the transmit antenna beam. Additionally, in some controller512may use negative power adjustments as a second, tiebreaking criteria, such as by i) identifying the candidate transmit antenna beams with the fewest positive power adjustments, and ii) if there are multiple candidate transmit antenna beams tied for the fewest positive power adjustments, identifying from those the candidate transmit antenna beam that has the most negative power adjustments. Controller512may select that candidate transmit antenna beam as the transmit antenna beam in stage616.

In another example with power control feedback, controller512may select the transmit antenna beam by summing the power adjustments for the candidate transmit antenna beams. For instance, controller512may identify all the power adjustments, positive and negative, for each candidate transmit antenna beam, and then sum those power adjustments to get a power adjustment total (e.g., the sum of power adjustments across all transmitted blocks of payload data for each candidate transmit antenna beam). Controller512may then identify the candidate transmit antenna beam with the lowest power adjustment total, and select that candidate transmit antenna beam as the transmit antenna beam in stage616.

Accordingly, with flow chart600, terminal device102may beamsweep with payload data and select a transmit antenna beam based on retransmission or power control feedback. As discussed above, terminal device102may not need to wait for network access node110to schedule dedicated transmit beamsweeping; terminal device102may instead execute stages612-616without waiting for network access node110. Additionally, because terminal device102transmits payload data during the beamsweeping, terminal device102may not need to use power or occupy radio resources when performing transmit beamsweeping. This extends battery life and improve radio resource efficiency.

In some aspects, terminal device102may execute this type of transmit beamsweeping with a 3GPP radio access technology, such as LTE or 5G NR. In such cases, controller512may generate some of the blocks of payload data as, for example, physical upload shared channel (PUSCH) instances. One or more of the blocks of payload data may therefore be a PUSCH transport blocks. In one example where controller512maps blocks of payload data to candidate transmit antenna beams by alternating, controller512may assign PUSCH instances 1, 3, 5, and 7 to a first candidate transmit bean, and PUSCH instances 2, 4, 6, and 8 to a second candidate transmit beam. With that mapping, digital transmitter510may alternate between transmitting blocks of payload data with the first and second candidate transmit beams.

In some aspects, controller512may be configured to select the overall pool of blocks of payload data based on the priority of data. For instance, controller512may look at all the blocks of payload data that are scheduled for transmission, and may select the overall pool of blocks of payload data based on their data priority. Controller512may then allocate the overall pool of blocks of payload data to the plurality of candidate transmit antenna beams, but may not perform transmit beamsweeping with the other blocks of payload data. To take one example, controller512may select the overall pool of blocks of payload data with predefined priority rules. For instance, controller512may only sweep a given block of payload data (e.g., include it in the overall pool) if the block of payload data contains lower priority data, such as MAC service data units (SDUs) as opposed to MAC control elements (CEs; or equivalently other control data). Thus, controller512may not perform transmit beamsweeping on important data. This can help avoid losing important data, such as if terminal device102tried to transmit critical data with a poor candidate transmit antenna beam and network access node110could not receive it.

In some aspects, controller512may use padding so that only part of the blocks of payload data carry useful information. This can provide further protection against data loss, as a lost block of payload data will lose only some payload data instead of an entire block (e.g., an entire PUSCH transport block). For example, in some aspects controller512may be configured as a media access control (MAC) layer and digital transmitter510may be configured as a physical (PHY) layer. Controller512may therefore obtain layer input data (e.g., any type of user-plane or control plane data) and perform MAC processing on the layer input data to obtain layer output data. Using 3GPP terminology as an example, the layer input data is termed a MAC SDU (service data unit; e.g., a single block of the layer input data) and the layer output data is termed a MAC PDU (protocol data unit; e.g., a single block of the layer output data). Controller512, acting as a MAC layer, may provide the layer output data to digital transmitter510, which acts as a PHY layer. Digital transmitter510may treat the MAC PDUs its layer input data (e.g., PHY SDUs) and may perform PHY processing on the layer input data to obtain its layer output data (e.g., PHY PDUs). Digital transmitter510may then transmit its layer output data via RF transceiver504and antenna system502.

As part of its MAC processing, controller512may insert padding bits into the MAC PDUs. The MAC PDUs (transport blocks) may therefore include information bits and padding bits, where the information bits carry header and information data (carrying the MAC layer input data) and the padding bits are arbitrary bits that do not carry useful information. The ratio of padding bits to information bits is termed the padding ratio, where increasing the padding ratio means increasing the number of padding bits relative to the number of information bits.

FIG. 8shows an example of MAC processing according to some aspects. Acting as a MAC layer, controller512may obtain MAC SDUs from an upper layer (e.g., part of controller512, or from another component). Controller512may attach a header to the MAC SDUs to obtain MAC subPDUs. Controller612may also generate MAC control elements (CEs) and attach headers to the MAC CEs to obtain other MAC subPDUs. InFIG. 8's example, there are two MAC CEs—CE1and CE2—where MAC CE1has a fixed size and MAC CE2has a variable size. In some aspects, the header for a given MAC subPDU may indicate the format of the MAC SDU (e.g., whether it includes a MAC SDU or a variable- or fixed-size MAC CE), the logical channel (e.g., the logical channel that carries the MAC SDU), and/or the length of the MAC SDU. This format is described in 3GPP TS 38.321 for a 3GPP example.

AsFIG. 8shows, controller512may also be configured to insert optional padding into the MAC PDUs. For instance, controller512may generate a MAC subPDU that includes padding bits. In contrast to the MAC SDUs carried in other MAC subPDUs, these padding bits may be arbitrary and may not carry useful information. Though the padding bits do not carry useful information, the MAC headers in a transport block do carry useful information, and these transport blocks are thus still considered blocks of payload data. When controller512inserts padding into a given MAC PDU, it may generate a header identifying the MAC subPDU as a padding subPDU (e.g., using a logical channel field in the header) and then insert padding bits into the MAC subPDU.

For the transmit beamsweeping of this disclosure, controller512may adjust the padding to help protect the blocks of payload data. For instance, controller512may treat the MAC PDUs as the blocks of payload data for transmit beamsweeping, where one MAC PDU forms one block of payload data. Controller512can then use a large padding ratio to help avoid excessive loss of payload data. As introduced above, a large padding ratio means a larger number of padding bits (e.g., a large subPDU with padding in the MAC PDU) than information bits. Thus, if controller512generates a given block of transport data (MAC PDU) with a high padding ratio, that block of transport data will have a large amount of padding bits relative to information bits (e.g., the subPDU padding will be large). If terminal device102transmits that block of payload data with a poor candidate transmit antenna beam that (e.g., that does not point at network access node110), network access node110may not be able to receive and decode the block of payload data. As such, the block payload data will be lost, and terminal device102may need to retransmit it. However, if the padding ratio is high, most of the lost data will be padding bits, not information bits. Because only a small amount of information bits are lost, the data loss is mitigated. Conversely, if the padding ratio is low, most of the lost data will be information bits. This data loss can be considerably worse.

To help mitigate the impacts of payload data loss, controller512may adjust the padding ratio of the blocks of payload data (e.g., transport blocks) when it performs transmit beamsweeping on payload data.FIG. 9shows exemplary flow chart900illustrating an example of this according to some aspects. AsFIG. 9shows, terminal device102may perform stages602-616of flow chart900in the same manner as stages602-616of flow chart600inFIG. 6. Accordingly, controller512may update its receive antenna beam with receive beamsweeping, select a plurality of candidate transmit antenna beams to beamsweep, decide whether to perform dedicated transmit beamsweeping or transmit beamsweeping with payload data, sweep across the plurality of candidate transmit antenna beams with blocks of payload data, and use the resulting feedback to select a transmit antenna beam.

In addition, for flow chart900terminal device102may also perform stages902-904to adjust the padding ratio of the blocks of payload data used for transmit beamsweeping. That is, while terminal device102may perform largely the same procedure as flow chart600, terminal device102may also adjust the blocks of payload data to vary their padding ratio. As shown inFIG. 9, after controller512selects the plurality of candidate transmit antenna beams (stage606) and decides to perform transmit beamsweeping with payload data (stage608), controller512may determine a padding ratio for the payload data in stage902. For instance, in stage902controller512may determine a padding ratio to use for the blocks of payload data used for the transmit beamsweeping, where the padding ratio is the ratio of padding to information bits in the blocks of payload data (e.g., transport blocks or MAC PDUs).

In some aspects, controller512may determine the padding ratio based on channel conditions for terminal device102. For instance, if terminal device102has a reliable radio link with network access node110, controller512may select a lower padding ratio. This means that the blocks of payload data will include more information bits and less padding bits. Because channel conditions are strong, there is a higher likelihood network access node110will be able to receive and decode the blocks of payload data, especially when terminal device102transmits with a poor candidate transmit antenna beam. Thus, it may not be as important for terminal device102to mitigate data loss, meaning a lower padding ratio is justified. Conversely, if terminal device102has a weak radio link with network access node110, controller512may select a higher padding ration. Because channel conditions are weak, there is a higher chance that the blocks of payload data will be lost, particularly when terminal device102uses a candidate transmit antenna beam that is not pointed at network access node110. When blocks of payload data are lost, less of the lost data will be information bits. Using a higher padding ratio can therefore help to mitigate the data loss.

In one example, digital receiver508may perform radio measurements on signal received from network access node110, and controller512may then use the radio measurements to determine the padding ratio in stage902. For instance, digital receiver508may be configured with measurement circuitry, and may receive and process signals from network access node110to determine radio measurements. These radio measurements can be, for example, signal strength or signal quality measurements. In some aspects, digital receiver508may estimate the pathloss or propagation range based on the radio measurements. Though the radio measurements may be downlink measurements, estimating the pathloss or propagation range based on the radio measurements may indicate the strength or quality of the uplink channel. In other aspects, digital transmitter510may obtain a timing advance (TA) that it uses to time its transmissions so they arrive at network access node110according to a set timing schedule. When terminal device102is far from network access node110, transmissions need to travel farther, and so the timing advance is larger. Conversely, when terminal device102is close to network access node110, transmissions do not need to travel as far, and so the timing advance is smaller. Thus, the timing advance also indicates propagation range.

Controller512may then use the pathloss, propagation range, or timing advance to select the padding ratio in stage902. Herein, these metrics are collectively termed uplink channel indicators. If the uplink channel indicators indicate a poor uplink channel (e.g., high pathloss, high propagation range, or large timing advance), controller512may select a higher padding ratio. That is, if the radio link with network access node110is likely poor, controller512may insert more padding bits into the blocks of transport data. As explained above, this can help mitigate data loss. Conversely, if the uplink channel indicators indicate a strong uplink channel, controller512may select a lower padding ratio. Thus, if the radio link with network access node110is strong, controller512may insert fewer padding bits into the blocks of transport data. Since the rate of data loss is likely low, controller512may not need to mitigate data loss as aggressively.

In some aspects, controller512may use a predefined mapping of radio measurements to padding ratios, where uplink channel indicators indicating a poor channel map to higher padding ratios and where uplink channel indicators indicating a strong channel map to lower padding ratios. When it obtains an uplink channel indicator from digital receiver508, controller512may use the predefined mapping to determine which padding ratio maps to the uplink channel indicator's value. Controller512may then select that padding ratio in stage902. By doing so, controller512may select a padding ratio based on the channel conditions.

After controller512selects a padding ratio, controller512may generate blocks of payload data with the padding ratio in stage904. These are the blocks of payload data that controller512uses for the transmit beamsweeping. As described for one example inFIG. 8, controller512may be configured to receive layer input data from upper layers and to process that layer input data to obtain layer output data, where the layer output data is the blocks of payload data. As part of that processing, controller512may be configured to add headers to the layer input data and, optionally, to add padding bits. Thus, in stage904controller512may add padding bits to the layer input data, generate headers for the layer output data, and partition the layer output data to form blocks of payload data that have a ratio of padding bits to information bits. In some aspects, controller512may use the exemplary procedure described above forFIG. 8, such as where controller512acts as a MAC layer, processing MAC SDUs to generate MAC PDUs and including a MAC subPDU with padding bits in the MAC PDU. Controller512may select the number of MAC SDUs, the size of MAC SDUs, and the size of the MAC subPDU with padding (e.g., the number of padding bits) based on the padding ratio, where the padding ratio controls the number of padding bits to information bits in the resulting MAC PDU. In this example, each MAC PDU may be a block of payload data (e.g., a transport block), which controller512may provide to digital transmitter508.

In the same manner as flow chart600, digital transmitter508may receive the blocks of payload data from controller512and then transmit the blocks of payload data for the plurality of candidate transmit beams in stage612. Acting as a PHY layer, digital transmitter508may then perform PHY processing on each block of payload data (e.g., treating it as a PHY SDU) and transmit the blocks of payload data via RF transceiver504and antenna array504. Controller512may then observe the retransmission and transmit power feedback in stage614and select a transmit antenna beam based on the feedback in stage616.

By selecting the padding ratio in this manner, controller512may help mitigate for data loss, especially when some of the candidate transmit beams are not pointed at network access node110. Thus, even when some of the candidate transmit antenna beams are not pointed at network access node110, controller512may avoid excessive data loss. That is, to protect the payload data, terminal device102may use MAC padding to fill only part of the transport blocks (e.g., PUSCH transport blocks) with useful data (a subset of MAC SDUs) while filling the other space with padded bits. Controller512may program the MAC headers of the transport blocks with reduced data length, so if network access node110successfully decodes the transport block, it can still pick up the information bits (based on the MAC header) while discarding the padding bits. In an extreme case, controller512may fill the blocks of payload data with padding bits while the MAC header data length is configured as 0. This results in a completely empty transport block, which can be viewed as a probe signal to probe the transmit beam quality while the information bits (useful uplink data) are fully protected within terminal device102's data buffer.FIG. 10shows an example of this according to some aspects. As shown inFIG. 10, controller512may, in some aspects, generate the blocks of payload data as PUSCH transport blocks (TBs), which are equivalent to MAC PDUs. Controller512may obtain a MAC SDU from the upper layers that includes information bits (useful data). Based on the padding ratio, controller512may add padding bits to the MAC SDU. Controller512may then attach a MAC header to the MAC SDU and padding bits, where the header indicates the length of the PUSCH TB. Because the padding bits are not useful information, controller512may indicate in the header that the PUSCH TB is as long as the MAC SDU, meaning that the length does not include the padding bits. Thus, when network access node110successfully decodes the PUSCH TB, it can still pick up only the useful data—the MAC SDU—based on the MAC header. The padding bits are not useful data, and network access node110may not need to decode them.

As previously described, controller512may identify an overall pool of blocks of payload data that it will use for transmit beamsweeping. In some aspects, controller512may identify the overall pool based on the priority of information in the payload data. For instance, some payload data may be high-priority data, like critical control channels, while other payload data may be less important, such as video or voice data. Because transmit beamsweeping with payload data can increase the likelihood of losing the data, in some aspects controller512may select blocks of payload data with lower priority information and include those blocks of payload data in the overall pool. Controller512may identify other blocks of payload data with higher priority information and leave those blocks of payload data out of the overall pool. As there is an increased risk of data loss, with this technique controller512can avoid losing critical data. Instead, controller512may transmit beamsweep with lower priority information, and transmit the higher priority information without transmit beamsweeping. In some aspects, controller512may classify blocks of payload data as high priority or low priority based on priority information such as quality of service (QoS) indicators or based on logical channels (e.g., logical channels that carry control data as high priority and logical channels that carry user data as low priority).

In some aspects, controller512may dynamically adapt the padding ratio based on the feedback from network access node110. For instance, as controller512receives retransmission and transmit power feedback from network access node110, controller512may be able to estimate which candidate transmit antenna beams are suitable and which are poor. Controller512may then use a higher padding ratio for poor candidate transmit antenna beams, and use a lower padding ratio for strong candidate transmit antenna beams. In one example using retransmission feedback, controller512may initially transmit blocks of payload data with different candidate transmit antenna beams and receive retransmission feedback for the candidate transmit antenna beams. While the transmit beamsweeping procedure is still ongoing, controller512may calculate a tentative retransmission rate for each candidate transmit antenna beam based on the retransmission feedback received so far. Though the tentative retransmission rates may not be fully accurate yet, controller512may still use them to select padding ratios to transmit other blocks of payload data for the candidate transmit antenna beams. For instance, controller512may select lower padding ratios for candidate transmit antenna beams that have low tentative retransmission rates, and may select higher padding ratios for candidate transmit antenna beams that have higher tentative retransmission rates. Controller512may then generate the next blocks of payload data for the candidate transmit antenna beams based on these different padding ratios. With this approach, controller512may provide more protection to the payload data for poor candidate transmit antenna beams (those having high tentative retransmission rates) and less protection to the payload data for strong candidate transmit antenna beams (those having low tentative retransmission rates).

Similarly, when using transmit power feedback, controller512may transmit blocks of payload data with the plurality of candidate transmit antenna beams and receive transmit power feedback in response. Controller512may then determine a tentative count of positive power adjustments (or, similarly, a tentative sum of power adjustments) for the different candidate transmit antenna beams. Using the tentative count of positive power adjustments, controller512may select higher padding ratios for candidate transmit antenna beams with higher tentative counts and select lower padding ratios for candidate transmit antenna beams with lower tentative counts. Because higher tentative counts of positive power adjustments can indicate a poor candidate transmit antenna beam, controller512may provide more protection to payload data that has higher chance of being lost. If using a tentative sum of power adjustments, controller512may similarly select higher padding ratios for candidate transmit antenna beams with higher tentative sums and select lower padding ratios for candidate transmit antenna beams with lower tentative sums.

In some aspects, controller512may also select the padding ratio in stage902based on the operating band. For instance, higher bands like 39 GHz have higher signal attenuation than lower bands like 28 GHz. As such, controller512may select higher padding ratios for higher operating bands and lower padding ratios for lower operating bands. With this, controller512may provide more protection to payload data when operating at higher frequencies with greater signal attenuation.

As explained above, one issue with dedicated transmit beamsweeping is that network access node110does not know when terminal device102updates its receive antenna beam. As a result, network access node110will not know when to schedule dedicated transmit beamsweeping. Terminal device102will be stuck with the prior transmit antenna beam until network access node110eventually scheduled dedicated transmit beamsweeping. Thus, in some aspects, controller512may use the padding bits in the blocks of transport data to send a dedicated message to network access node. This dedicated message may request network access node110to schedule dedicated transmit beamsweeping for terminal device102. For instance, when generating blocks of payload data, controller512may insert a predefined message into the padding bits. TakingFIG. 8's example, controller512may insert the predefined message into the MAC subPDU with padding. The predefined message may be a predefined bit string that is agreed on in advance by network access node110and terminal device102.

Thus, when terminal device102updates its receive antenna beam, controller512may trigger dedicated transmit beamsweeping by inserting the predefined message into the padding bits of a block of payload data and sending the block of payload data to network access node110(e.g., by providing it to digital transmitter510for transmission). Because network access node110knows the predefined message in advance, network access node110may detect the predefined message when it decodes the block of payload data. This informs network access node110that terminal device102is requesting dedicated transmit beamsweeping. Recognizing this, network access node110may then schedule dedicated transmit beamsweeping for terminal device102. Terminal device102may then use the dedicated transmit beamsweeping to send beamsweeping reference signals with the plurality of candidate transmit antenna beams, and network access node110may report back which candidate transmit antenna beams yielded the highest received signal power. Terminal device102may then select a transmit antenna beam based on that feedback.

FIG. 11shows exemplary method1100of performing beamsweeping at a wireless device according to some aspects. As shown inFIG. 11, method1100includes transmitting, with a first candidate antenna beam, a first plurality of blocks of payload data (stage1102), transmitting, with a second candidate antenna beam, a second plurality of blocks of payload data (stage1104), receiving, from a receiver device, feedback on the first plurality of blocks and the second plurality of blocks that requests retransmission or a transmit power adjustment (stage1106), selecting, based on the feedback, a candidate antenna beam as a transmit antenna beam (stage1108), and transmitting payload data to the receiver device with the transmit antenna beam (stage1110).

While the above descriptions and connected figures may depict electronic device components as separate elements, skilled persons will appreciate the various possibilities to combine or integrate discrete elements into a single element. Such may include combining two or more circuits for form a single circuit, mounting two or more circuits onto a common chip or chassis to form an integrated element, executing discrete software components on a common processor core, etc. Conversely, skilled persons will recognize the possibility to separate a single element into two or more discrete elements, such as splitting a single circuit into two or more separate circuits, separating a chip or chassis into discrete elements originally provided thereon, separating a software component into two or more sections and executing each on a separate processor core, etc.

The following examples pertain to further aspects of this disclosure:

Example 1 is a method of performing beamsweeping at a wireless device, the method including transmitting, with a first candidate antenna beam, a first plurality of blocks of payload data, transmitting, with a second candidate antenna beam, a second plurality of blocks of payload data, receiving, from a receiver device, feedback on the first plurality of blocks and the second plurality of blocks that requests retransmission or a transmit power adjustment, selecting, based on the feedback, a candidate antenna beam as a transmit antenna beam, and transmitting payload data to the receiver device with the transmit antenna beam.

In Example 2, the subject matter of Example 1 can optionally include wherein the feedback includes one or more acknowledgements (ACKs) or negative acknowledgements (NACKs) that indicate whether the receiver device successfully received the first plurality of blocks of payload data or the second plurality of blocks of payload data.

In Example 3, the subject matter of Example 1 or 2 can optionally further include determining, based on the feedback, a retransmission rate for the first candidate antenna beam and a retransmission rate for the second candidate antenna beam, wherein selecting the transmit antenna beam is based on the retransmission rate for the first candidate antenna beam and the retransmission rate for the second candidate antenna beam.

In Example 4, the subject matter of Example 1 or 2 can optionally further include determining, based on the feedback, retransmission rates for a plurality of candidate antenna beams that include the first candidate antenna beam and the second candidate antenna beam, wherein selecting the transmit antenna beam includes identifying, from the plurality of candidate antenna beams, a candidate transmit antenna beam that has the lowest retransmission rate, and selecting the identified candidate transmit antenna beam as the transmit antenna beam.

In Example 5, the subject matter of Example 1 can optionally include wherein the feedback includes one or more transmit power adjustments that request the wireless device to increase or decrease its transmit power.

In Example 6, the subject matter of Example 1 can optionally further include receiving transmit power adjustments for a plurality of candidate antenna beams that include the first candidate antenna beam and the second candidate antenna beam, wherein selecting the candidate antenna beam as the transmit antenna beam based on the feedback includes selecting, from the plurality of candidate antenna beams, the candidate antenna beam based on a number of positive power adjustments received for the candidate antenna beam.

In Example 7, the subject matter of Example 6 can optionally include wherein the positive power adjustments request the wireless device to increase its transmit power, and wherein the positive power adjustments are received in response to one or more blocks of payload data transmitted with the candidate antenna beam.

In Example 8, the subject matter of Example 6 can optionally include wherein selecting, from the plurality of candidate antenna beams, the candidate antenna beam includes identifying which candidate antenna beam of the plurality of candidate antenna beams has a lowest number of positive power adjustments, and selecting the identified candidate antenna beam as the transmit antenna beam.

In Example 9, the subject matter of any one of Examples 5 to 8 can optionally include wherein the transmit power adjustments are transmit power control (TPC) commands.

In Example 10, the subject matter of any one of Examples 1 to 9 can optionally further include before transmitting the first plurality of blocks of payload data, performing a receive beamsweeping procedure to select a receive antenna beam for receiving payload data from the receiver device, and selecting a plurality of candidate antenna beams, including the first candidate antenna beam and the second candidate antenna beam, based on the receive antenna beam, wherein selecting the candidate antenna beam as the transmit antenna beam includes selecting the candidate antenna beam from the plurality of candidate antenna beams based on the feedback.

In Example 11, the subject matter of Example 10 can optionally include wherein selecting the plurality of candidate antenna beams based on the receive antenna beam includes identifying one or more predefined transmit antenna beams that neighbor the receive antenna beam in steering direction, and including the one or more predefined transmit antenna beams in the plurality of candidate antenna beams.

In Example 12, the subject matter of Example 10 can optionally include wherein selecting the plurality of candidate antenna beams based on the receive antenna beam includes identifying one or more predefined transmit antenna beams based on a predefined mapping that maps different receive antenna beams to different candidate transmit antenna beams based on spatial correspondence, and including the one or more predefined transmit antenna beams in the plurality of candidate antenna beams.

In Example 13, the subject matter of any one of Examples 1 to 10 can optionally include wherein the payload data is user-plane or control-plane data that carries information bits.

In Example 14, the subject matter of any one of Examples 1 to 13 can optionally include wherein the first plurality of blocks of payload data are transport blocks (TBs).

In Example 15, the subject matter of any one of Examples 1 to 14 can optionally further include selecting an overall pool of blocks of payload data to use for transmit beamsweeping over a plurality of candidate antenna beams that include the first candidate antenna beam and the second candidate antenna beam, assigning a first subset of the overall pool of blocks of payload data to the first plurality of blocks of payload data, and assigning a second subset of the overall pool of blocks of payload data to the second plurality of blocks of payload data.

In Example 16, the subject matter of Example 15 can optionally include wherein selecting the overall pool of blocks of payload data includes selecting the overall pool of blocks of payload data based on a priority of data contained in the overall pool of blocks of payload data.

In Example 17, the subject matter of any one of Examples 1 to 16 can optionally further include obtaining information that indicates a quality of a wireless channel between the wireless device and the receiver device, selecting a padding ratio based on the quality of the wireless channel indicated by the information, and generating the first plurality of blocks of payload data to include a number of padding bits depending on the padding ratio.

In Example 18, the subject matter of Example 17 can optionally include wherein the padding bits are arbitrary bits that do not carry useful information, and wherein the padding ratio controls a ratio of padding bits to information bits in the first plurality of blocks of payload data.

In Example 19, the subject matter of Example 17 or 18 can optionally include wherein the information is an estimated pathloss of the wireless channel, an estimated propagation range of the wireless channel, or a timing advance of the wireless channel.

In Example 20, the subject matter of Example 17 or 18 can optionally include wherein the information includes the feedback on the first plurality of blocks and the second plurality of blocks that requests retransmission or a transmit power adjustment.

In Example 21, the subject matter of any one of Examples 17 to 19 can optionally further include increasing the padding ratio if the information indicates a decrease in the quality of the wireless channel, and decreasing the padding ratio if the information indicates an increase in the quality of the wireless channel.

In Example 22, the subject matter of any one of Examples 1 to 21 can optionally include wherein transmitting the payload data to the receiver device with the transmit antenna beam includes configuring an antenna array to transmit with the transmit antenna beam, and transmitting the payload data via the antenna array.

In Example 23, the subject matter of Example 22 can optionally include wherein configuring the antenna array to transmit with the transmit antenna beam includes setting a plurality of phase shifters to a set of beamforming weights for the transmit antenna beam, wherein the plurality of phase shifters connect to different antenna elements of the antenna array.

Example 24 is a digital processing chip arrangement including a digital transmitter configured to transmit, via an antenna array, a first plurality of blocks of payload data with a first antenna beam, and to transmit, via the antenna array, a second plurality of blocks of payload data with a second antenna beam, a digital receiver configured to receive, via the antenna array, feedback on the first plurality of blocks and the second plurality of blocks that requests retransmission or transmit power adjustment, and a controller configured to select, based on the feedback, an antenna beam as a transmit antenna beam, the digital transmitter further configured to transmit, via the antenna array, payload data to the receiver with the transmit antenna beam.

In Example 25, the subject matter of Example 24 can optionally include wherein the feedback includes one or more acknowledgements (ACKs) or negative acknowledgements (NACKs) that indicate whether the receiver device successfully received the first plurality of blocks of payload data or the second plurality of blocks of payload data.

In Example 26, the subject matter of Example 24 or 25 can optionally include wherein the controller is further configured to determine, based on the feedback, a retransmission rate for the first candidate antenna beam and a retransmission rate for the second candidate antenna beam, and wherein the controller is configured to select the transmit antenna beam based on the retransmission rate for the first candidate antenna beam and the retransmission rate for the second candidate antenna beam.

In Example 27, the subject matter of Example 24 or 25 can optionally include wherein the controller is further configured to determine, based on the feedback, retransmission rates for a plurality of candidate antenna beams that include the first candidate antenna beam and the second candidate antenna beam, and wherein the controller is configured to select the transmit antenna beam by identifying, from the plurality of candidate antenna beams, a candidate transmit antenna beam that has the lowest retransmission rate, and selecting the identified candidate transmit antenna beam as the transmit antenna beam.

In Example 28, the subject matter of Example 24 can optionally include wherein the feedback includes one or more transmit power adjustments that request the digital signal processing chip arrangement to increase or decrease its transmit power.

In Example 29, the subject matter of Example 24 can optionally include wherein the digital receiver is further configured to receive transmit power adjustments for a plurality of candidate antenna beams that include the first candidate antenna beam and the second candidate antenna beam, and wherein the controller is configured to select the candidate antenna beam as the transmit antenna beam based on the feedback by selecting, from the plurality of candidate antenna beams, the candidate antenna beam based on a number of positive power adjustments received for the candidate antenna beam.

In Example 30, the subject matter of Example 29 can optionally include wherein the positive power adjustments request the digital processing chip arrangement to increase its transmit power, and wherein the digital receiver is configured to receive the positive power adjustments in response to one or more blocks of payload data transmitted with the candidate antenna beam.

In Example 31, the subject matter of Example 30 can optionally include wherein the controller is configured to select, from the plurality of candidate antenna beams, the candidate antenna beam by identifying which candidate antenna beam of the plurality of candidate antenna beams has a lowest number of positive power adjustments, and selecting the identified candidate antenna beam as the transmit antenna beam.

In Example 32, the subject matter of any one of Examples 28 to 31 can optionally include wherein the transmit power adjustments are transmit power control (TPC) commands.

In Example 33, the subject matter of any one of Examples 24 to 32 can optionally include wherein the digital receiver is further configured to, before the digital transmitter transmits the first plurality of blocks of payload data, perform a receive beamsweeping procedure to select a receive antenna beam for receiving payload data from the receiver device, and wherein the controller is configured to select a plurality of candidate antenna beams, including the first candidate antenna beam and the second candidate antenna beam, based on the receive antenna beam, and wherein the controller is configured to select the candidate antenna beam from the plurality of candidate antenna beams based on the feedback.

In Example 34, the subject matter of Example 33 can optionally include wherein the controller is configured to select the plurality of candidate antenna beams based on the receive antenna beam by identifying one or more predefined transmit antenna beams that neighbor the receive antenna beam in steering direction, and including the one or more predefined transmit antenna beams in the plurality of candidate antenna beams.

In Example 35, the subject matter of Example 33 can optionally include wherein the controller is configured to select the plurality of candidate antenna beams based on the receive antenna beam by identifying one or more predefined transmit antenna beams based on a predefined mapping that maps different receive antenna beams to different candidate transmit antenna beams based on spatial correspondence, and including the one or more predefined transmit antenna beams in the plurality of candidate antenna beams.

In Example 36, the subject matter of any one of Examples 24 to 33 can optionally include wherein the payload data is user-plane or control-plane data that carries information bits.

In Example 37, the subject matter of any one of Examples 24 to 36 can optionally include wherein the first plurality of blocks of payload data are transport blocks (TBs).

In Example 38, the subject matter of any one of Examples 24 to 37 can optionally include wherein the controller is further configured to select an overall pool of blocks of payload data to use for transmit beamsweeping over a plurality of candidate antenna beams that include the first candidate antenna beam and the second candidate antenna beam, assign a first subset of the overall pool of blocks of payload data to the first plurality of blocks of payload data, and assign a second subset of the overall pool of blocks of payload data to the second plurality of blocks of payload data.

In Example 39, the subject matter of Example 38 can optionally include wherein the controller is configured to select the overall pool of blocks of payload data by selecting the overall pool of blocks of payload data based on a priority of data contained in the overall pool of blocks of payload data.

In Example 40, the subject matter of any one of Examples 24 to 39 can optionally include wherein the controller is further configured to obtain information that indicates a quality of a wireless channel between the antenna array and the receiver device, select a padding ratio based on the quality of the wireless channel indicated by the information, and generate the first plurality of blocks of payload data to include a number of padding bits depending on the padding ratio.

In Example 41, the subject matter of Example 40 can optionally include wherein the padding bits are arbitrary bits that do not carry useful information, and wherein the padding ratio controls a ratio of padding bits to information bits in the first plurality of blocks of payload data.

In Example 42, the subject matter of Example 40 or 41 can optionally include wherein the information is an estimated pathloss of the wireless channel, an estimated propagation range of the wireless channel, or a timing advance of the wireless channel.

In Example 43, the subject matter of Example 40 or 41 can optionally include wherein the information includes the feedback on the first plurality of blocks and the second plurality of blocks that requests retransmission or a transmit power adjustment.

In Example 44, the subject matter of any one of Examples 40 to 42 can optionally include wherein the controller is further configured to increase the padding ratio if the information indicates a decrease in the quality of the wireless channel, and to decrease the padding ratio if the information indicates an increase in the quality of the wireless channel.

In Example 45, the subject matter of any one of Examples 24 to 44 can optionally include wherein, when the digital transmitter transmits the payload data to the receiver device with the transmit antenna beam, the controller is configured to configure the antenna array to transmit with the transmit antenna beam.

In Example 46, the subject matter of Example 45 can optionally include wherein the controller is configured to configure the antenna array to transmit with the transmit antenna beam by setting a plurality of phase shifters to a set of beamforming weights for the transmit antenna beam, wherein the plurality of phase shifters connect to different antenna elements of the antenna array.

Example 47 is a wireless device including a radio frequency transceiver, an antenna array, and one or more processors configured to transmit and receive signals with the radio frequency transceiver and the antenna array, and further configured to transmit, with a first antenna beam, a first plurality of blocks of payload data, transmit, with a second antenna beam, a second plurality of blocks of payload data, receive from a receiver device, feedback on the first plurality of blocks and the second plurality of blocks that requests retransmission or transmit power adjustments, select, based on the feedback, an antenna beam as a transmit antenna beam, and transmit payload data to the receiver device with the transmit antenna beam.

In Example 48, the subject matter of Example 47 can optionally include wherein the feedback includes one or more acknowledgements (ACKs) or negative acknowledgements (NACKs) that indicate whether the receiver device successfully received the first plurality of blocks of payload data or the second plurality of blocks of payload data.

In Example 49, the subject matter of Example 47 or 48 can optionally include wherein the one or more processors are further configured to determine, based on the feedback, a retransmission rate for the first candidate antenna beam and a retransmission rate for the second candidate antenna beam, and wherein the one or more processors are configured to select the transmit antenna beam based on the retransmission rate for the first candidate antenna beam and the retransmission rate for the second candidate antenna beam.

In Example 50, the subject matter of Example 47 or 48 can optionally include wherein the one or more processors are further configured to determine, based on the feedback, retransmission rates for a plurality of candidate antenna beams that include the first candidate antenna beam and the second candidate antenna beam, and wherein the one or more processors are configured to select the transmit antenna beam by identifying, from the plurality of candidate antenna beams, a candidate transmit antenna beam that has the lowest retransmission rate, and selecting the identified candidate transmit antenna beam as the transmit antenna beam.

In Example 51, the subject matter of Example 47 can optionally include wherein the feedback includes one or more transmit power adjustments that request the wireless device to increase or decrease its transmit power.

In Example 52, the subject matter of Example 47 can optionally include wherein the one or more processors are further configured to receive transmit power adjustments for a plurality of candidate antenna beams that include the first candidate antenna beam and the second candidate antenna beam, and configured to select the candidate antenna beam as the transmit antenna beam based on the feedback by selecting, from the plurality of candidate antenna beams, the candidate antenna beam based on a number of positive power adjustments received for the candidate antenna beam.

In Example 53, the subject matter of Example 52 can optionally include wherein the positive power adjustments request the wireless device to increase its transmit power, and wherein the one or more processors are configured to receive the positive power adjustments in response to one or more blocks of payload data transmitted with the candidate antenna beam.

In Example 54, the subject matter of Example 53 can optionally include wherein the one or more processors are configured to select, from the plurality of candidate antenna beams, the candidate antenna beam by identifying which candidate antenna beam of the plurality of candidate antenna beams has a lowest number of positive power adjustments, and selecting the identified candidate antenna beam as the transmit antenna beam.

In Example 55, the subject matter of any one of Examples 51 to 54 can optionally include wherein the transmit power adjustments are transmit power control (TPC) commands.

In Example 56, the subject matter of any one of Examples 47 to 55 can optionally include wherein the one or more processors are further configured to before transmitting the first plurality of blocks of payload data, perform a receive beamsweeping procedure to select a receive antenna beam for receiving payload data from the receiver device, select a plurality of candidate antenna beams, including the first candidate antenna beam and the second candidate antenna beam, based on the receive antenna beam, and select the candidate antenna beam from the plurality of candidate antenna beams based on the feedback.

In Example 57, the subject matter of Example 56 can optionally include wherein one or more processors are configured to select the plurality of candidate antenna beams based on the receive antenna beam by identifying one or more predefined transmit antenna beams that neighbor the receive antenna beam in steering direction, and including the one or more predefined transmit antenna beams in the plurality of candidate antenna beams.

In Example 58, the subject matter of Example 56 can optionally include wherein one or more processors are configured to select the plurality of candidate antenna beams based on the receive antenna beam by identifying one or more predefined transmit antenna beams based on a predefined mapping that maps different receive antenna beams to different candidate transmit antenna beams based on spatial correspondence, and including the one or more predefined transmit antenna beams in the plurality of candidate antenna beams.

In Example 59, the subject matter of any one of Examples 47 to 56 can optionally include wherein the payload data is user-plane or control-plane data that carries information bits.

In Example 60, the subject matter of any one of Examples 47 to 59 can optionally include wherein the first plurality of blocks of payload data are transport blocks (TBs).

In Example 61, the subject matter of any one of Examples 47 to 60 can optionally include wherein the one or more processors are further configured to select an overall pool of blocks of payload data to use for transmit beamsweeping over a plurality of candidate antenna beams that include the first candidate antenna beam and the second candidate antenna beam, assign a first subset of the overall pool of blocks of payload data to the first plurality of blocks of payload data, and assign a second subset of the overall pool of blocks of payload data to the second plurality of blocks of payload data.

In Example 62, the subject matter of Example 61 can optionally include wherein the one or more processors are configured to select the overall pool of blocks of payload data by selecting the overall pool of blocks of payload data based on a priority of data contained in the overall pool of blocks of payload data.

In Example 63, the subject matter of any one of Examples 47 to 62 can optionally include wherein the one or more processors are further configured to obtain information that indicates a quality of a wireless channel between the antenna array and the receiver device, select a padding ratio based on the quality of the wireless channel indicated by the information, and generate the first plurality of blocks of payload data to include a number of padding bits depending on the padding ratio.

In Example 64, the subject matter of Example 63 can optionally include wherein the padding bits are arbitrary bits that do not carry useful information, and wherein the padding ratio controls a ratio of padding bits to information bits in the first plurality of blocks of payload data.

In Example 65, the subject matter of Example 63 or 64 can optionally include wherein the information is an estimated pathloss of the wireless channel, an estimated propagation range of the wireless channel, or a timing advance of the wireless channel.

In Example 66, the subject matter of Example 64 or 65 can optionally include wherein the information includes the feedback on the first plurality of blocks and the second plurality of blocks that requests retransmission or a transmit power adjustment.

In Example 67, the subject matter of any one of Examples 63 to 65 can optionally include wherein the one or more processors are further configured to increase the padding ratio if the information indicates a decrease in the quality of the wireless channel, and to decrease the padding ratio if the information indicates an increase in the quality of the wireless channel.

In Example 68, the subject matter of any one of Examples 47 to 67 can optionally include wherein, when transmitting the payload data to the receiver device with the transmit antenna beam, the one or more processors are configured to configure the antenna array to transmit with the transmit antenna beam.

In Example 69, the subject matter of Example 68 can optionally include wherein the one or more processors are configured to configure the antenna array to transmit with the transmit antenna beam by setting a plurality of phase shifters to a set of beamforming weights for the transmit antenna beam, wherein the plurality of phase shifters connect to different antenna elements of the antenna array.

Example 70 is a non-transitory computer readable medium storing instructions that, when executed by one or more processors of a wireless device, cause the wireless device to perform the method of any one of Examples 1 to 23.

Example 71 is a wireless device including one or more processors, and a memory storing instructions that, when executed by the one or more processors, cause the wireless device to perform the method of any one of Examples 1 to 23.