Misalignment correction for orbital angular momentum (OAM) beams

Abstract

Aspects of the present disclosure relate to devices, wireless communication devices, methods, and other aspects for correcting misalignment for orbital angular momentum beams. In one aspect, a wireless communication device comprises: a beamforming network comprising a plurality of antenna ports and a plurality of beam ports, where the plurality of antenna ports are positioned for transmitting orbital angular momentum (OAM) beams; a plurality of output phase shifters, where each output phase shifter is coupled to a corresponding antenna port of the plurality of antenna ports; and a control circuit coupled to the plurality of output phase shifters and configured to select phase shift values for the plurality of output phase shifters to correct for misalignment of the OAM beam.

Description

Technical Field

[0001] Generally speaking, the present disclosure relates to electronics and wireless communications. For example, aspects of the present disclosure relate to orthogonal orbital angular momentum (OAM) beams for wireless communications. Background Art

[0002] Wireless communication devices and technologies are becoming more and more common. Wireless communication devices typically send and receive communication signals. Communication signals are typically processed by a variety of different components and circuits. In some modern communication systems, many different wavelengths of electromagnetic waves may be used in a single device, and specialized transmission and reception configurations may be used to generate and receive orthogonal signals in the same wireless path. Providing consistent signals in such an environment may involve additional complexity in the wireless communication system. Summary of the invention

[0003] Various implementations of systems, methods, and devices within the scope of the appended claims each have several aspects, no single one of which is solely responsible for the desirable attributes described herein.Without limiting the scope of the appended claims, some notable features are described herein.

[0004] In some aspects, systems and techniques for misalignment correction of orthogonal orbital angular momentum (OAM) beams are described. Systems, apparatus, methods, and computer-readable media for misalignment correction as described herein are disclosed. According to at least one example, a device for misalignment correction as described herein is provided. The device includes: a beamforming network, which includes a plurality of antenna ports and a plurality of beam ports, wherein the plurality of antenna ports are positioned for transmitting an orbital angular momentum (OAM) beam; a plurality of output phase shifters, wherein each output phase shifter is coupled to a corresponding antenna port in the plurality of antenna ports; and a control circuit, which is coupled to the plurality of output phase shifters and is configured to select phase shift values ​​for the plurality of output phase shifters to correct the misalignment of the OAM beam.

[0005] In some aspects, the beamforming network is a Butler matrix. In some aspects, a plurality of antenna elements, wherein the Butler matrix includes outputs electrically coupled to the plurality of antenna elements. In some aspects, the beamforming network is a Rotman lens. In some aspects, an antenna array includes a plurality of antenna elements, wherein each antenna element of the plurality of antenna elements is coupled to the corresponding antenna port of the plurality of antenna ports.

[0006] In some aspects, the plurality of antenna elements are positioned in a circular formation having a predefined radius, wherein a corresponding position of each antenna element is associated with an orbital phase of the OAM beam. In some aspects, the control circuit is configured to measure the misalignment of the OAM beam in communication with a remote wireless communication device. In some aspects, the misalignment comprises one or more of an off-axis misalignment, a non-parallel misalignment, and a rotational mismatch alignment.

[0007] In some aspects, the plurality of output phase shifters include varactor phase shifters tunable using phase shift values ​​determined by a projection of each antenna element on the transmit-receive line to a corresponding antenna element of the remote wireless communication device.

[0008] In some aspects, the control circuit is configured to measure the misalignment by calculating the alignment for each pair of antenna elements to determine a phase shift value for each phase shifter associated with the corresponding antenna element and antenna port. In some aspects, the plurality of output phase shifters include passive phase shifters. In some aspects, the plurality of output phase shifters include bidirectional phase shifters for providing reciprocal phase adjustment of a transmit OAM beam and a receive OAM beam in the OAM beam.

[0009] In some aspects, transceiver circuitry is coupled to the plurality of beam ports and provides a plurality of OAM beams to the plurality of beam ports, wherein each of the plurality of beam ports receives signals of the plurality of OAM beams associated with samples at a set orbital phase corresponding to each beam port.

[0010] In some aspects, the samples of the plurality of OAM beams are sampled at a rate sufficient to avoid phase aliasing between the OAM beams. In some aspects, the misalignment comprises a rotational mismatch, and wherein the control circuit is configured to adjust the differential phase of the signal for each beam port based on the rotational mismatch.

[0011] In another aspect, a method for misalignment is provided. The method includes: initiating, by a wireless communication device, a communication link with a remote wireless communication device, wherein the wireless communication device and the remote wireless communication device are configured to communicate using orbital angular momentum (OAM) beams, and wherein the wireless communication device includes a Butler matrix, an antenna array, and a plurality of phase shifters coupling antenna ports of the Butler matrix to corresponding elements of the antenna array; measuring, by the wireless communication device, a misalignment between the antenna array of the wireless communication device and the antenna array of the remote wireless communication device; selecting, by the wireless communication device, phase shift values ​​for the plurality of phase shifters to compensate for the misalignment; and transmitting a plurality of OAM beams between the wireless communication device and the remote wireless communication device using the phase shift values.

[0012] In another aspect, a wireless communication device for misalignment correction is provided. The device includes: a unit for initiating a communication link with a remote wireless communication device using an orbital angular momentum (OAM) beam; a unit for measuring, by the wireless communication device, a misalignment between the antenna array of the wireless communication device and the antenna array of the remote wireless communication device; a unit for selecting, by the wireless communication device, phase shift values ​​for the plurality of phase shifters to compensate for the misalignment; and a unit for transmitting a plurality of OAM beams between the wireless communication device and the remote wireless communication device using the phase shift values.

[0013] In another aspect, a wireless communication device is provided. The wireless communication device includes: a transceiver circuit configured to generate signals for a plurality of orbital angular momentum (OAM) beams; a plurality of beam ports coupled to the transceiver circuit to transmit the plurality of OAM beams; a plurality of antenna ports, wherein each antenna port is associated with a corresponding orbital phase of the plurality of OAM beams; a plurality of three-decibels 90-degree couplers and internal phase shifters configured to couple the plurality of beam ports to the plurality of antenna ports; and a plurality of antenna elements positioned in a circular array, wherein each element is coupled to a corresponding antenna port of the plurality of antenna ports.

[0014] The foregoing and other features and embodiments will become more fully apparent after reference to the following description, claims and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the accompanying drawings, like reference numerals refer to like parts throughout the various views unless otherwise indicated. For reference numerals with letter character designations (such as "102a" or "102b"), the letter character designations may distinguish between two similar parts or elements present in the same figure. When it is intended that a reference numeral encompass all parts having the same reference numeral in all figures, the letter character designations of the reference numerals may be omitted.

[0016] Figure 1 is a schematic diagram illustrating a wireless communication system for communicating with wireless devices that can be implemented in accordance with various aspects described herein.

[0017] Figure 2 is a schematic diagram illustrating a wireless communication system for communicating with wireless devices and base stations that can be implemented in accordance with various aspects described herein.

[0018] Figure 3 is a block diagram illustrating aspects of a wireless communication device for OAM beam misalignment correction in accordance with aspects described herein.

[0019] Figure 4A Various aspects of an OAM beam are shown in accordance with various aspects described herein.

[0020] Figure 4B Aspects of an antenna array for use with OAM beams in accordance with various aspects described herein are shown.

[0021] Figure 5 Aspects of a Butler matrix associated with various aspects described herein are shown.

[0022] Figure 6 Aspects of a Butler matrix associated with various aspects described herein are shown.

[0023] Figure 7

[0013] Aspects of a wireless communication device for OAM beam misalignment correction in accordance with various aspects described herein are shown.

[0024] Figure 8 Various aspects of OAM beam misalignment correction according to various aspects described herein are shown.

[0025] Fig. 9 Various aspects of a method for correcting OAM beam misalignment according to various aspects described herein are shown.

[0026] Fig.10 Aspects of an apparatus for correcting OAM beam misalignment according to various aspects described herein are shown.

[0027] Fig.11is a schematic diagram of an electronic device that can be used with aspects of the present disclosure. DETAILED DESCRIPTION

[0028] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of an exemplary implementation and is not intended to represent the only implementation in which the present invention may be practiced. The term "exemplary" used throughout the specification means "used as an example, instance, or illustration" and should not necessarily be interpreted as being preferred or advantageous over other exemplary implementations. For the purpose of providing a thorough understanding of the exemplary implementations, the detailed description includes specific details. In some instances, some devices are shown in block diagram form. The same reference numerals may be used to identify common drawing elements between the following figures.

[0029] Cellular communication systems use centralized base stations and system controllers to allow mobile devices to send and receive wireless data from a variety of locations. Such base stations require a large amount of resources, and some environments (especially at higher frequencies) are difficult to cover in the communication system without blind spots due to signal absorption or signal reflection. Communication coverage in some environments may involve multiple fixed base stations that can wirelessly communicate with each other to manage system performance and distribute communication loads. Orbital angular momentum (OAM) multiplexing is a possible technology that can be used to increase system throughput for a given communication band (especially at millimeter wave (mmW) frequencies and other higher frequency bands). One difficulty about OAM multiplexing is that signal beam misalignment may degrade performance. Even when both endpoints are fixed in a relatively stable manner, this misalignment may also degrade performance. Temperature changes, weather changes, and atmospheric changes, wind-generated movement of the pole on which the communication device is mounted, and other such small changes in fixed-position devices may cause performance degradation (due to misalignment caused by such changes).

[0030] Various aspects described herein include beamforming network-based OAM multiplexing systems for mmW and higher frequency band communications, wherein phase shifters are positioned between the beamforming network output and the antenna array elements. Such controllable phase shifters can be used to dynamically compensate for the misalignments described above in the described beamforming network-based OAM multiplexing systems. Depending on the specific components and phase shifters used, various aspects can improve the operation of the OAM multiplexing system by utilizing low complexity and low power phase shifter solutions to allow misalignment tracking and correction.

[0031] Figure 11 is a schematic diagram illustrating a communication system 120 that may include devices that may use OAM multiplexing communications with misalignment tracking and correction in accordance with various aspects described herein. The wireless communication system 120 may be a Long Term Evolution (LTE) system, a Code Division Multiple Access (CDMA) system, a Global System for Mobile Communications (GSM) system, a Wireless Local Area Network (WLAN) system, a 5G NR (New Radio) system, or some other wireless system. The CDMA system may implement Wideband CDMA (WCDMA), CDMA1X, Evolution Data Optimized (EVDO), Time Division Synchronous CDMA (TD-SCDMA), or some other version of CDMA. For simplicity, Figure 1 A wireless communication system 120 is shown that includes base stations 130 and 132 and one system controller 140. In general, a wireless communication system may include any number of base stations and any set of other network entities that may communicate using OAM multiplexing in accordance with aspects described herein.

[0032] The wireless device 110 may also be referred to as a user equipment (UE), a mobile station, a terminal, an access terminal, a subscriber unit, a station, etc. The wireless device 110 may be a cellular phone, a smart phone, a tablet device, or other such mobile device (e.g., a device integrated with a display screen). Other examples of the wireless device 110 include a wireless modem, a personal digital assistant (PDA), a handheld device, a laptop computer, a smart book, a netbook, a tablet device, a cordless phone, a medical device, a device configured to connect to one or more other devices (e.g., through the Internet of Things), a wireless local loop (WLL) station, a Bluetooth device, etc. The wireless device 110 may communicate with the wireless communication system 120. The wireless device 110 may also receive signals from a broadcast station (e.g., a broadcast station 134) and / or signals from a satellite (e.g., a satellite 150 in one or more global navigation satellite systems (GNSS)). The wireless device 110 may support one or more radio technologies for wireless communication, such as LTE, WCDMA, CDMA 1X, EVDO, TD-SCDMA, GSM, 802.11, 5G, etc. In some examples, UE 110 may use OAM multiplexing communications according to aspects described herein. Some such examples may operate at relatively high frequencies (e.g., in the sub-THz range) where multiple antennas and / or beamforming devices may have a small form factor.

[0033] Figure 2 2 is a schematic diagram showing an environment 200 including an electronic device 202 and a base station 204. The environment 200 may be part of the system 120, the device 202 may be similar to the device 110, and the base station 204 may be similar to the system 120. Figure 1base station. Furthermore, although a base station 204 and an electronic device 202 are described according to various aspects described herein, in addition to OAM multiplexing between a base station 204 and an electronic device 202 having a relatively stable position (e.g., a stable position of an antenna array for OAM transmission and reception as described below) where misalignment tracking can be used to correct for misalignment of a wireless link 206 where a high-frequency point-to-point OAM beam can operate between two devices (e.g., such as a base station 204 and an electronic device 202)), a similar wireless link 206 can also be applied between base stations communicating via OAM multiplexing as described herein. Figure 2 In the example of , the electronic device 202 is depicted as a smart phone, however, the electronic device 202 can be implemented as any suitable computing or other electronic device, such as a cellular base station, a broadband router, an access point, a cellular or mobile phone, a gaming device, a navigation device, a media device, a laptop computer, a desktop computer, a tablet computer, a server, a network attached storage (NAS) device, a smart appliance, a vehicle-based communication system, an Internet of Things (IoT) device, and the like.

[0034] Base station 204 communicates with electronic device 202 via wireless link 206, which may be implemented as any suitable type of wireless link. Although base station 204 is depicted as a base station tower of a cellular radio network, base station 204 may represent or be implemented as another device, such as a satellite, a cable TV headend, a terrestrial television broadcast tower, an access point, a peer device, a mesh network node, a router, a fiber optic line, another electronic device in general, etc. Thus, electronic device 202 may communicate with base station 204 or another device via a wired connection, a wireless connection, or a combination thereof.

[0035] The wireless link 206 may include a downlink of data or control information transmitted from the base station 204 to the electronic device 202 and an uplink of other data or control information transmitted from the electronic device 202 to the base station 204. The wireless link 206 may be implemented using any suitable communication protocol or standard, such as 3rd Generation Partnership Project Long Term Evolution (3GPP LTE), 5G New Radio (3GPP 5G NR), IEEE 802.11, IEEE 802.16, Bluetooth, or the like. TM etc.

[0036] The electronic device 202 includes a processor 208 and a computer-readable storage medium (CRM 210). The processor 208 may include any type of processor configured to execute processor-executable instructions (e.g., code) stored by the CRM 210, such as an application processor or a multi-core processor. The CRM 210 may include any suitable type of data storage medium, such as volatile memory (e.g., random access memory (RAM)), non-volatile memory (e.g., flash memory), optical media, magnetic media (e.g., disk or tape), etc. In the context of the present disclosure, the CRM 210 is implemented to store instructions 212, data 214, and other information for the electronic device 202, and therefore does not include a transient propagating signal or carrier wave.

[0037] The electronic device 202 may also include an input / output port 216 (I / O port 216) or a display 218. The I / O port 216 implements data exchange or interaction with other devices, networks, or users. The I / O port 216 may include a serial port (e.g., a universal serial bus (USB) port), a parallel port, an audio port, an infrared (IR) port, and the like. The display 218 may be implemented as a screen or projection that presents graphics (e.g., one or more graphic images) of the electronic device 202, such as a user interface associated with an operating system, program, or application. Alternatively or in addition, the display 218 may be implemented as a display port or virtual interface through which the graphical content of the electronic device 202 is transmitted or presented.

[0038] For communication purposes, the electronic device 202 also includes a modem 220, a wireless transceiver 222, and at least one antenna 230. The wireless transceiver 222 includes a converter unit (CU) 224 and a transceiver (TRX) unit 226. The wireless transceiver 222 uses RF wireless signals to provide connectivity to corresponding networks and other electronic devices connected thereto. Additionally or alternatively, the electronic device 202 may include a wired transceiver, such as an Ethernet or fiber optic interface, for communicating through a personal or local network, an intranet, or the Internet. The wireless transceiver 222 can facilitate communication through any suitable type of wireless network described herein.

[0039] The modem 220 (such as a baseband modem) can be implemented as a system on chip (SoC) that provides a digital communication interface for data, voice, messaging, and other applications of the electronic device 202. The modem 220 may also include a baseband circuit to perform a high-speed sampling process, which may include analog-to-digital conversion (ADC), digital-to-analog conversion (DAC), gain correction, skew correction, frequency shift, and the like. The modem 220 may also include logic for performing in-phase / quadrature (I / Q) operations (such as synthesis, encoding, modulation, demodulation, and decoding). More generally, the modem 220 may be implemented as a digital signal processor (DSP) or a processor configured to perform signal processing to support communication via one or more networks. Alternatively, the ADC or DAC operation may be performed by a separate component or another illustrated component (such as a wireless transceiver 222).

[0040] The wireless transceiver 222 may include circuits, logic, and other hardware for sending or receiving wireless signals for at least one communication frequency band. In operation, the wireless transceiver 222 may implement at least one radio frequency transceiver unit to process data and / or signals associated with transmitting data of the electronic device 202 via the antenna 230. Typically, the wireless transceiver 222 may include filters, switches, amplifiers, etc. for routing and processing signals sent or received via the antenna 230. Typically, the wireless transceiver 222 includes multiple transceiver units (e.g., for different wireless protocols (such as WLAN and WWAN), or for supporting different frequency bands or frequency band combinations).

[0041] The elements of the electronic device 202 are described above, and the base station 204 may also have similar corresponding elements in addition to any other elements supporting the base station functions. The processor 258 may have a similar structure and function as the processor 208, and the CRM 260 together with the instructions 262 and the data 264 may have a similar structure and function as the CRM 210, the instructions 212 and the data 214. The I / O port 266 and the modem 270 may have a similar structure and function as the I / O port 216 and the modem 220 above. The wireless transceiver 272 may include a converter unit 274 and a transceiver unit 276 and an antenna 280. The transceiver 272 may include a 3GPP standard structure or other communication structures described above for the implementation of a base station and a wireless communication device for performing OAM multiplexing communication using an antenna array within the antenna 280 configured for OAM multiplexing. Such antenna 280 and communication elements within wireless transceiver 272 may be used for any number of wireless links in addition to wireless link 206, including to other base stations, small cells, macro cells, or other such elements of environment 200 (each of which may include communication with the environment 200). Figure 2and OAM devices and functions for wireless communications as described below).

[0042] Figure 3 is a block diagram illustrating aspects of a wireless communication apparatus 300 for OAM beam misalignment correction according to aspects described herein. The wireless communication apparatus 300 may be an element of any device or station (e.g., base station 130, 132, 204 or electronic device 202) that is part of a wireless communication system. As described above, mmW or higher frequency wireless communications may use OAM multiplexing for improved data throughput over a given communication band, but misalignment between an OAM transmit antenna array and a receive array may negatively impact performance. Figure 3 Examples of wireless communication devices that may include structures for OAM communications that may be measured and corrected using low impact (eg, low cost, low power usage, low space usage) system additions for correction are shown.

[0043] The wireless communication device includes a beamforming network 315. In some implementations, the beamforming network 315 is a Butler matrix consisting of a coupler and a phase shifter. The operation of the Butler matrix used for the beamforming network 315 to implement OAM communication is described in more detail below. The following description includes Butler matrix implementation details, but other beamforming networks (such as beamforming networks that use Rotman lenses to generate OAM beams or components thereof) can be used in other implementations. Any such beamforming network 315 can be coupled to a phase shifter 340 as described herein to provide small angle correction for misalignment. The signal connection 310 can provide a connection to the beamforming network 315 for sending or receiving OAM signals. The control circuit 305 may include a sampling circuit for generating a transmission input for the signal connection 310 when the wireless communication device 300 is used for OAM transmission, and a processing circuit for separating a separate OAM channel when the wireless communication device 300 is used to receive OAM signals. Further, the control circuit 305 can manage signals, measurements, and control adjustments for identifying misalignments between a transmitting device and a receiving device involved in OAM communications. The control circuit 305 can be (partially or entirely) included in the processor 208 or 258 and / or in the modem 220 or 270. The signal connection 310, the beamforming network 315, and the phase shifter 340 can be (partially or entirely) included in the wireless transceiver 222 or 272. The antenna array 350 can be an example of the antenna 230 or 280.

[0044] In various implementations, different processes can be used to determine misalignment. In one implementation, a detector can be placed on each receiving antenna after the phase shifter and before the Butler matrix. The corresponding transmission system will send a known pilot sequence with an OAM waveform. The detector will measure the energy, amplitude and / or phase on each receiving antenna element. Such detection can occur in a broadband measurement, or in a measurement in a selected frequency range or multiple selected frequency ranges. When the phase, amplitude and / or energy measured by the detector is known and provided to the control circuit of the device, the control circuit can perform a search or calculation to determine which offset is most suitable for the received pilot sequence. The identified offset value can be used to control the output phase shifter according to the various aspects described herein.

[0045] In some implementations, a dedicated misalignment antenna may be used to determine the misalignment and control the output phase shifter. In some implementations, an antenna grid may be used to measure the strongest energy and correlate the measured energy with the expected OAM beam to determine the misalignment. A control circuit may be used to accept the energy measured from the antenna grid, calculate the misalignment, and calculate the offset for controlling the output phase shifter. In other implementations, the transmitting system may determine the offset and send a signal indicating the misalignment to the receiving system. The receiving system may determine the phase shifter setting based on the control signal sent from the transmitting system. In other implementations, other systems may be used to determine the misalignment for controlling the output phase shifter.

[0046] The output connection of the beamforming network 315 is coupled to the antenna array 350 via the output phase shifter 340. The beamforming network 315 can handle the transmission or reception of OAM signals from the antenna array 350, but does not include a mechanism for correcting misalignment between the antenna array 350 and the corresponding antenna array of a remote wireless communication device that communicates with the wireless communication device 300 via the OAM beam. The output phase shifter 340 includes a phase shifting element between each antenna port of the beamforming network 315 and a corresponding antenna element of the antenna array 350. When a misalignment is identified, a controllable phase shift value of each of the output phase shifters 340 can be selected to modify the communication signal to compensate for the misalignment, thereby maintaining signal performance. Additional details of the OAM beam, the Butler matrix for OAM communication, misalignment, and corrections for the effects of misalignment on the OAM beam are described below.

[0047] Figure 4A Various aspects of an OAM beam 400 are shown according to various aspects described herein. Specifically, Figure 4AFive different orthogonal OAM beams 400 are shown, which are shown as beams 410, 411, 412, 413 and 414. Orbital angular momentum (OAM) multiplexing is a physical method for multiplexing electromagnetic waves using the polarization of light to produce mutually orthogonal beams. The diagram for each of these orthogonal beams includes an isometric view of the polarization over time (as an associated spiral structure 421), a slice of the isometric view on a two-dimensional plane (shown as a phase wavefront 422), and an intensity projection of the energy composition of each beam in the two-dimensional view (shown as an intensity distribution 423).

[0048] OAM multiplexing relies on circular polarization at different rates of change of polarization. For example, beams 410 and 411 show a clockwise rotation of the polarization of the associated beams over time, where beam 410 has a polarization that changes at twice the frequency of the rotation of beam 411. The speed or frequency of this rotation can be referred to as the orbital angular momentum of a given beam. Similarly, beams 413 and beam 414 have polarizations that rotate in opposite directions of the polarizations of beams 410 and 411, where the polarization of beam 414 is approximately twice that of beam 413. In contrast, beam 412 has a base polarization that does not rotate, and therefore the polarization of beam 412 is zero. The beams can be characterized by the following equation:

[0049] Φ(θ)=e imθ (1)

[0050] Where Φ is the amplitude of the signal, m is the current multiple of the base OAM value (eg, as shown in FIG. 4 ), and θ is the base phase value at a given time.

[0051] By sampling the orbital phases of the different beams at a sufficiently high rate to avoid aliasing, a receiver can receive beams 410-414 on a single antenna array, and can process the received signals by filtering according to the OAM (e.g., phase rotation characteristics) for each beam to receive separate data signals transmitted on each beam. By having beams with OAM that are integer multiples of a base OAM value (e.g., a base phase rotation value), and sampling at a sufficiently high frequency, OAM multiplexing can be achieved, which can send significantly more data in a given frequency band (compared to that achieved using a single OAM signal). Figure 4A Five OAM beams are shown, with beam 412 having 0 times the base OAM value, beam 410 having -1 times, beam 411 having +1 times, beam 412 having +2 times, and beam 414 having +2 times. Figure 4A Multiples of -2 to +2 are shown in FIG, but higher multiples of OAM beams may be used in different implementations as long as the orbital phase is sampled at a high enough rate to avoid phase aliasing and signal loss.

[0052] As described herein, an OAM system may be configured for multiple OAM multiplexed channels, but not all multiplexed channels need to be used at any given time period. For example, for a system supporting seven channels (e.g., m = {-3 to +3}), the system may use only certain channels (e.g., -3, -1, +1, and +3 channels) even if the system supports other channels. In some implementations, such use may be dynamic, for example, based on signaling conditions where a receiver is having difficulty distinguishing between adjacent channel beam signals (e.g., between +2 and +3 signals).

[0053] Furthermore, in the Butler matrix implementation described below, 8 outputs are used, and therefore a symmetric design will not allow zero phase (e.g., m=0) beams (e.g., therefore in a symmetric configuration, m={-4, -3, -2, -1, +1, +2, +3, +4}). In some implementations, the use of phase offsets may be used for beams to allow zero OAM beams (e.g., therefore m={-4, -3, -2, -1, 0, +1, +2, +3}, but a +4 beam or corresponding symmetric beam will not exist at one end).

[0054] Figure 4B 4 shows aspects of an antenna array 450 for use with an OAM beam in accordance with aspects described herein. Figure 4A As shown, an OAM beam involves a beam with a phase that varies with time. In order to transmit and receive such an OAM beam, an antenna array that can generate and receive beams at different phases is used. Antenna array 450 shows a circular array of antenna elements 452-1 to 452-8 configured with an array radius 454. In order to avoid aliasing of OAM beams with an OAM multiple m, the number of antenna elements in the antenna array is designed to be greater than 2m+1. For three OAM beams (e.g., as described above, in the absence of a zero OAM beam, m={-1, +1}), the number of antenna elements is greater than 2(1)+1=3, so 3 or more antenna elements are used. For seven OAM beams (e.g., m={-3, -2, -1, 0, +1, +2, +3}), the number of antenna elements is greater than 2(3)+1=7, so 8 or more antenna elements are used.

[0055] Although the Butler matrix cannot create a zero index in OAM, it is possible to use added phase shifters to shift the phase on the antenna elements. Using the added phase, a zero index can be created in OAM.

[0056] Each of the antenna elements 452-1 through 452-8 (e.g., or a different number of elements depending on the design) is coupled to a corresponding phase shifter (e.g., in phase shifter 340) and is coupled to an antenna port of a Butler matrix (e.g., beamforming network 315) via the corresponding phase shifter. The antenna elements and Butler matrix are constructed to have a one-to-one correlation between the Butler matrix ports and the number of antenna elements (e.g., an 8-input 8-output Butler matrix will have 8 outputs coupled to separate antenna elements through separate phase shifters). In other implementations, the Butler matrix outputs may each be associated with two or more antenna elements, depending on the RF design for the particular implementation.

[0057] Figure 5 Aspects of a Butler matrix associated with various aspects described herein are shown.A Butler matrix is ​​a passive feed network with N inputs and N outputs with directional beam steering capabilities for a unified array of N antennas. Figure 5 A conventional linear array communication system 500 having a Butler matrix structure is shown. The system 500 includes eight input ports, which are shown as beam ports 510-1 to 510-8. The Butler matrix includes a plurality of internal Butler matrix phase shifters 530 (e.g., kXπ / 8 phase shifters) and Butler matrix couplers 520 (e.g., 3 dB / 90 degree couplers). The network of phase shifters 530 and couplers 520 in the conventional linear array system 500 generates an array configuration at antenna ports 540-1 to 540-8 so that the signals transmitted or received on the corresponding antenna elements 542-1 to 542-8 have directivity as shown by directional beams 550-1 to 550-8.

[0058] Figure 6 1 shows aspects of a Butler matrix associated with various aspects described herein. Figure 4B A circular antenna array such as the antenna array 450 shown in FIG. Figure 5 ), the beams associated with the Butler matrix have varying phase values ​​rather than varying directivity (e.g., as shown by the directional beams 550-1 to 550-8 associated with the linear array of antenna elements 542-1 to 542-8). Figure 6 This difference is illustrated in system 600 of FIG. 5 , where the output from a Butler matrix with an associated antenna array configured for OAM generates different electromagnetic field patterns with different OAM characteristics (e.g., as Figure 4A), rather than a field pattern resulting in different beam directivities as described for a conventional Butler matrix used with a linear array.

[0059] Figure 6 A system 600 is shown having a Butler matrix structure coupled to a circular antenna array having antenna elements 650-1 to 650-8. The system 600 includes beam ports 610-1 to 610-8. For transmission signals, the beam ports 610-1 to 610-8 accept signal inputs and process the signal inputs through the phase shifters 630 and couplers 620 of the Butler matrix structure (e.g., including kXπ / 8 internal phase shifters and 3dB / 90 degree couplers as described above) for transmission using the antenna elements 650-1 to 650-8. Control circuitry (e.g., control circuitry 305) or transceiver circuitry (e.g., transceiver 222 or 272) can generate signals for the beam ports 610-1 to 610-8, which will be sent as multiplexed OAM beams via the antenna elements 650-1 to 650-8.

[0060] Similarly, for receive operation, antenna elements 650-1 to 650-8 will receive OAM beams. The signals received by each antenna element will be transmitted through the coupler 620 and phase shifter 630 of the Butler matrix, where the corresponding signals are output at beam ports 610-1 to 610-8. The control circuitry or processing circuitry of the transceiver can then further process the signals output at beam ports 610-1 to 610-8 to process independent data streams from each of the orthogonal OAM beams received at the antenna array.

[0061] Figure 7 Various aspects of a wireless communication device for OAM beam misalignment correction according to various aspects described herein are shown. In any communication, the above-mentioned OAM transmission function will be performed by one device, and another remote device will perform the corresponding reception function. For OAM communication, this involves a source device 710 (e.g., a transmitting device having a beam source signal 712) and a destination device 720 (e.g., a receiving device). Because the polarization described above for the OAM beam is directional, the directionality of the transmit (TX)-receive (RX) path affects the ability of the destination device 720 to identify the OAM beam signal. In a system having two circular antenna arrays with circuits for OAM transmission and reception (e.g., two instances of system 600, one for the source device and one for the destination device), the alignment between the circular antenna arrays (e.g., such as antenna array 450 or antenna elements 650-1 to 650-8) will affect the beam destination signal 722 received at the destination device 720.

[0062] For example, the misalignment can be off-axis (e.g., horizontal or vertical) misalignment, non-parallel misalignment (e.g., when the array planes for the Tx and Rx elements are not parallel), and rotational mismatch (e.g., where for a given OAM beam configuration, the corresponding antenna elements are rotated out of phase with each other, as further described below).

[0063] Figure 8 Various aspects of OAM beam misalignment correction according to various aspects described herein are shown. Figure 8 The wireless communication device 800 shown includes a Butler matrix having beam ports 810-1 to 810-8 for transmitting signals to the processing circuit of the device, a phase shifter 830 and a coupler 820 inside the Butler matrix, and antenna elements 850-1 to 850-8 of a (circular) antenna array as described above. However, the wireless communication device 800 additionally includes output phase shifters 840-1 to 840-8 (e.g., similar to the output phase shifter 340 described above). The phase shifters are tunable and can be configured with phase shift values ​​that are determined based on sensed measurements associated with the projection of each antenna element on the Tx-Rx line to the corresponding antenna element of another device in communication. The tuning values ​​can be used to compensate for the above-mentioned Figure 7 As mentioned above, although a Butler matrix is ​​shown, a different beamforming network (e.g., a Rotman lens) may be used instead. The Butler matrix may be a beamforming network 315 ( Figure 3 ), phase shifter 830 may be an example of phase shifter 340, antenna element 850 may be an example of antenna array 350, and beam port 810 may be an example of signal connection 310. Figure 8 An 8x8 Butler matrix is ​​shown in the example of FIG, but other sized Butler matrices (e.g., 4x4, 16x16, etc.) may be used for antenna arrays having fewer or greater numbers of elements. Further, although in Figure 8 A circular array of antennas is shown in , but other configurations may be implemented. For example, other beamforming networks may be used with arrays having different configurations. Phase shifter 840 is labeled herein as an output phase shifter, but it will be understood that phase shifter 840 may receive a signal output from a beamforming network (e.g., a Butler matrix), or may provide an input signal to a beamforming network (e.g., when apparatus 800 is used to receive an OAM beam, rather than to transmit an OAM beam).

[0064] Since the mismatch for each multiplexed OAM beam between a given Tx antenna array and the corresponding Rx antenna array is common, the mismatch can be corrected using a phase shifter that is common to the Butler matrix beams. Figure 7 The misalignment 716 shown in can be characterized as follows:

[0065]

[0066] as well as

[0067]

[0068] Where α is the angle between the Tx array center and the Rx array center, R is a predefined radius of a circular formation of elements of the antenna array of the system for performing the calculation (e.g., array radius 454), n is an antenna element index (e.g., where each antenna element such as antenna elements 650-1 to 650-8 has an associated index), N is the number of antennas, and a is a phase vector implemented on the antenna. For the radius value R, if both the transmit and receive systems in a particular implementation apply beam misalignment correction, each (e.g., both the transmit and receive systems) can calculate an associated radius for the corresponding system (e.g., the transmit system for the radius of the transmit array and the receive system for the radius of the receive array).

[0069] The sensing signals may be managed by control circuitry coupled to such a device and used to identify misalignment between the Tx antenna array and the Rx antenna array. Results and data from such sensing signals may be used to calculate alignment for each pair of antenna elements (e.g., between the Tx and Rx antenna arrays) to determine a phase shift value for each phase shifter to compensate for the calculated misalignment. The calculated phase shift values ​​may then be provided to the phase shifters 840-1 to 840-8 to provide a small angle correction to the OAM beam, which improves the quality of the signal at the destination device.

[0070] In some cases, as described above, the system described for OAM multiplexing communication is specific to the orientation and direction of the Tx-Rx path (e.g., Tx-Rx path 715), and thus such OAM communication can be suitable for fixed-position equipment (e.g., for fronthaul or backhaul wireless links). A common such device is a fixed-position device on a pole of a base station. Although two such devices mounted on a pole and configured to communicate with each other have a largely fixed position and directionality, factors such as wind, temperature, atmospheric conditions, and other such variables may modify the Tx-Rx path sufficiently to degrade the associated OAM multiplexing channel performance. Phase shifters such as phase shifters 840-1 to 840-8 can provide small angle corrections in response to misalignment sensing signals generated between the Tx and Rx devices. In addition, since the above factors affect the angle change over time, the control circuit can be used to periodically measure the misalignment and generate updated phase adjustment values ​​to compensate for the measured misalignment. In some implementations, a threshold performance value is used to trigger an updated misalignment measurement, such that a misalignment measurement is performed if system performance drops below a threshold level (e.g., when the error becomes too large). Such a control system can be used to avoid unnecessary updates to misalignment compensation when small misalignments have a negligible effect on communication performance, while also providing an option for dynamic channel improvement based on compensating for misalignment when overall channel performance drops to a level that affects operation.

[0071] The use of such phase shifters improves the operation of associated devices by improving signal performance in OAM communications while adding low complexity elements to the devices, particularly when compared to alternative solutions using larger antenna arrays and using beam steering implemented in the antenna array signals.

[0072] In various implementations, phase shifters 840-1 to 840-8 may be implemented as different types of phase shifters. In some implementations, active phase shifters may be used, such as varactors, Cartesian phase shifters, micro-electromechanical systems (MEMS) phase shifters, ferrite phase shifters, or other such active (e.g., providing signal amplification) phase shifters. Varactor phase shifters may be implemented with sensitive phase tuning characteristics (e.g., analog phase shifting functions with soft or finely adjustable phase shift values) to provide accurate compensation for the above-mentioned misalignment.

[0073] The above example includes a Butler matrix with 8 inputs and 8 outputs. In other implementations, other structures, such as a Butler matrix with 16 inputs and 16 outputs, have a corresponding array of 16 antenna elements and associated (e.g., 16) phase shifters for each matched Butler matrix output and antenna element pair. Similarly, in other implementations, other numbers may be used for the NxN design of a particular implementation.

[0074] Furthermore, while the aspects described above illustrate OAM beams formed by a beamforming network based on a Butler matrix network, other such structures, such as a beamforming network based on a Rotman lens structure, may be used with added phase shifting elements in accordance with aspects described herein.

[0075] As described above, misalignments that affect signal performance are associated not only with the center alignment of the array as a whole, but also with the elements of the array. For example, the OAM signal is related to the rotational orientation of the elements within the array (e.g., an array in the Tx array with an associated index value that will correspond to a given index value in the Rx array in order to separate the multiplexed signal). Spatial misalignments for antenna elements can be identified on a per-element basis based on the difference in the projection of each element on a line combining the Tx and Rx spaces. As explained above, such spatial misalignments can depend on per-element positioning, and the varactor phase shifter implementation can include sufficient sensitivity to allow fine tuning of the phase shift value for such compensation.

[0076] In other implementations, passive phase shifters may be used to reduce device complexity and power usage. Such passive phase shifters for phase shifters 840-1 to 840-8 may, for example, include switched delay lines, high-pass-low-pass filter delay elements, Schiffman phase shifters, reflective phase shifters, load lines, and other such passive phase shifting elements. In some implementations, a combination of any such phase shifters described above may be used to balance performance with power usage and device complexity. The phase shifters may be configured to provide a tunable phase shift (e.g., based on instructions from the control circuit 305), such as in contrast to the fixed phase shift provided by the phase shifters within the Butler matrix.

[0077] The wireless communication devices described herein can maintain reciprocity for both Tx and Rx operations, so that a single device (e.g., wireless communication device 800) can perform both transmit and receive operations, thereby allowing bidirectional OAM multiplexed uplink and downlink communications with the same device. In some implementations, phase shifters for fine control of misalignment compensation are selected to facilitate such bidirectional reciprocity.

[0078] In addition to the spatial mismatch described above, rotational mismatch can also be handled by a system that uses differential phase offsets on adjacent antenna elements. When there is a rotational offset between the Tx and Rx antenna arrays, a potential null signal can be generated from the associated rotational error. By compensating the above phase shift values ​​from the OAM multiplexed communication using the phase shifter in the wireless communication device with the differential phase offset (e.g., Figure 4A The described aspects may also be used to resolve such rotation errors by combining the phase values ​​shown in FIG.

[0079] Fig. 9 is a flow chart describing an example of the operation of a method 900 for operation of a wireless communication device with OAM multiplexing functionality in accordance with various aspects described herein. In some aspects, the described operations may be performed by a device including a memory and a processing circuit, the processing circuit being coupled to the memory and configured to perform the operations of the method 900. In some aspects, the method 900 may be embodied as instructions stored in a non-transitory computer-readable storage medium (e.g., 210 or 260), which when executed by a processing circuit (e.g., control circuit 305) of the device causes the device to perform the operations of the method 900 described below. The blocks in the method 900 may be performed in the order shown or not, and in some embodiments, may be performed at least partially in parallel.

[0080] Method 900 includes block 902, which involves initiating, by a wireless communication device, a communication link with a remote wireless communication device. In some aspects, the wireless communication device and the remote wireless communication device are configured to communicate using an orbital angular momentum (OAM) beam. In some aspects, the wireless communication device includes a Butler matrix or other beamforming network, an antenna array, and a plurality of phase shifters that couple antenna ports of the Butler matrix or other beamforming network to corresponding elements of the antenna array. In other aspects, any other such structure or device element may be used to correct for OAM beam misalignment as described herein.

[0081] The method 900 includes block 904, which involves measuring, by the wireless communication device, a misalignment between an antenna array of the wireless communication device and an antenna array of a remote wireless communication device.

[0082] The method 900 includes block 906, which involves selecting, by the wireless communication device, phase shift values ​​for a plurality of phase shifters to compensate for misalignment.

[0083] The method 900 includes block 908, which involves using phase shift values ​​to transmit a plurality of OAM beams between the wireless communication device and a remote wireless communication device.

[0084] Fig.101 is a functional block diagram of a wireless communication device configured for OAM multiplexing according to various aspects described herein. The device 1000 includes a unit 1002 for initiating a communication link with a remote wireless communication device using an orbital angular momentum (OAM) beam. The device 1000 also includes a unit 1004 for measuring (e.g., by the wireless communication device or a component of the device 1000) a misalignment between an antenna array of the wireless communication device and an antenna array of the remote wireless communication device. The device 1000 further includes a unit 1006 for selecting phase shift values ​​for a plurality of phase shifters by the wireless communication device to compensate for the misalignment. The device 1000 also includes a unit 1008 for transmitting a plurality of OAM beams between the wireless communication device and the remote wireless communication device using the phase shift values.

[0085] The devices, networks, systems and specific units described herein for sending or receiving signals may be configured to communicate via one or more portions of the electromagnetic spectrum. The electromagnetic spectrum is typically subdivided into various categories, frequency bands, channels, etc. based on frequency or wavelength. In 5G NR, two initial operating bands have been identified as frequency range names FR1 (410MHz-7.125GHz) and FR2 (24.25GHz-52.6GHz). The frequencies between FR1 and FR2 are typically referred to as mid-band frequencies. Although a portion of FR1 is greater than 6GHz, FR1 is often referred to (interchangeably) as a "sub-6GHz" (below 6GHz) band in various documents and articles, and will be referred to as "sub-7GHz" (below 7GHz) in this article. Similar naming issues sometimes arise with respect to FR2, which is often (interchangeably) referred to as a "millimeter wave" (mmW) band in documents and articles, although it includes frequencies outside the extremely high frequency (EHF) band (30GHz–300GHz) identified by the International Telecommunication Union (ITU) as a "millimeter wave" or mmW band. Unless specifically noted otherwise, it should be understood that the terms "millimeter wave," mmW, etc., if used herein, may broadly refer to frequencies that may include mid-band frequencies, may be within FR2, or may be within the EHF band.

[0086] The circuit architecture described herein may be implemented on one or more ICs, analog ICs, mmWICs, mixed-signal ICs, ASICs, printed circuit boards (PCBs), electronic devices, etc. The circuit architecture described herein may also be constructed with various IC process technologies, such as complementary metal oxide semiconductor (CMOS), N-channel MOS (NMOS), P-channel MOS (PMOS), bipolar junction transistor (BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), heterojunction bipolar transistor (HBT), high electron mobility transistor (HEMT), silicon on insulator (SOI), etc.

[0087] The apparatus implementing the circuits described herein may be a stand-alone device or may be part of a larger device. The device may be: (i) a stand-alone IC, (ii) a collection of one or more ICs, which may include a memory IC for storing data and / or instructions, (iii) an RFIC such as an RF receiver (RFR) or RF transmitter / receiver (RTR) or corresponding mmW components, (iv) an ASIC such as a mobile station modem (MSM), (v) a module that may be embedded in other devices, (vi) a receiver, a cellular phone, a wireless device, a handset or a mobile unit, (vii) and the like.

[0088] Fig.11 1 is a schematic diagram illustrating an exemplary electronic device 1102, which includes a transceiver 1106, which may include and / or implement misalignment correction of an OAM beam. As shown, the electronic device 1102 includes an antenna 1104, an integrated circuit 1110, and a user input / output (I / O) interface 1108, which may be used together with the transceiver 1106 to implement misalignment correction of an OAM beam. The example of the integrated circuit 1110 or its core shown includes a microprocessor 1112, a graphics processing unit (GPU) 1114, a memory array 1116, and a modem 1118. Each component may be operably coupled to another component, such as the GPU 1114 being operably coupled to the user I / O interface 1108.

[0089] The electronic device 1102 may be a mobile or battery-powered device or a stationary device designed to be powered by a power grid. Examples of electronic devices 1102 include base stations (e.g., base stations 130, 132, 204, etc.), electronic devices (e.g., wireless devices 110, electronic devices 202, etc.), server computers, network switches or routers, blades in data centers, personal computers, desktop computers, notebooks or laptop computers, tablet computers, smart phones, entertainment appliances, or wearable electronic devices (such as smart watches, smart glasses, or clothing articles). The electronic device 1102 may also be a device or a portion thereof with embedded electronic devices. Examples of electronic devices 1102 with embedded electronic devices include passenger cars, industrial equipment, refrigerators or other household appliances, drones or other unmanned aerial vehicles (UAVs), or power tools.

[0090] For electronic devices with wireless capabilities, the electronic device 1102 includes an antenna 1104, which is coupled to a transceiver 1106 to enable reception or transmission of one or more wireless signals. The integrated circuit 1110 can be coupled to the transceiver 1106 to enable the integrated circuit 1100 to access received wireless signals or provide wireless signals for transmission via the antenna 1104. The electronic device 1102 as shown also includes at least one user I / O interface 1108. Examples of the user I / O interface 1108 include a keyboard, a mouse, a microphone, a touch-sensitive screen, a camera, an accelerometer, a tactile mechanism, a speaker, a display screen, or a projector. The transceiver 1106 may correspond to, for example, Figure 2 The wireless transceiver 222 or the wireless transceiver 272 may include an RF power sensor according to the examples described herein.

[0091] Integrated circuit 1110 may include, for example, one or more instances of a microprocessor 1112, a GPU 1114, a memory array 1116, a modem 1118, and the like. Microprocessor 1112 may be used as a central processing unit (CPU) or other general-purpose processor. Some microprocessors include different components that can be powered on or off individually, such as multiple processing cores. GPU 1114 may be particularly suitable for processing visual-related data for display, such as video data images. If visual-related data is not rendered or otherwise processed, GPU 1114 may be powered off in whole or in part. Memory array 1116 stores data for microprocessor 1112 or GPU 1114. Example types of memory for memory array 1116 include: random access memory (RAM), such as dynamic RAM (DRAM) or static RAM (SRAM); flash memory; and the like. If a program does not access data stored in memory, memory array 1116 may be powered off as a whole or block by block. The modem 1118 demodulates the signal to extract the encoded information, or modulates the signal to encode information into the signal. If there is no information to decode from the inbound communication or encode the outbound communication, the modem 1118 can be idle to reduce power consumption. The integrated circuit 1110 can include additional or alternative components other than those shown, such as an I / O interface, a sensor such as an accelerometer, another part of the transceiver or receiver chain, a custom or hard-coded processor such as an application specific integrated circuit (ASIC), and the like.

[0092] Integrated circuit 1110 may also include a system on chip (SoC). An SoC may integrate a sufficient number of different types of components to enable the SoC to provide computing functions as a notebook computer, mobile phone, or another electronic device using at least one chip. The components of an SoC or integrated circuit 1110 may generally be referred to as cores or circuit blocks. Fig.11 Examples of cores or circuit blocks include voltage regulators, main memory or cache memory blocks, memory controllers, general purpose processors, cryptographic processors, video or image processors, vector processors, radio units, interface or communication subsystems, wireless controllers, or display controllers in addition to those shown in . Any of these cores or circuit blocks (such as a central processing unit or a multimedia processor) may further include multiple internal cores or circuit blocks.

[0093] While selected aspects have been illustrated and described in detail, it will be understood that various substitutions and changes may be made therein without departing from the spirit and scope of the invention as defined by the following claims.

[0094] Illustrative aspects of the present disclosure include, but are not limited to:

[0095] Aspect 1. A wireless communication device, comprising: a beamforming network, comprising a plurality of antenna ports and a plurality of beam ports, wherein the plurality of antenna ports are positioned for transmitting an orbital angular momentum (OAM) beam; a plurality of output phase shifters, wherein each output phase shifter is coupled to a corresponding antenna port among the plurality of antenna ports; and a control circuit, which is coupled to the plurality of output phase shifters and is configured to select phase shift values ​​for the plurality of output phase shifters to correct misalignment of the OAM beam.

[0096] Aspect 2. The wireless communication device according to aspect 1, wherein the beamforming network is a Butler matrix.

[0097] Aspect 3: The wireless communication device according to any one of aspects 1 to 2 further includes: a plurality of antenna elements, wherein the Butler matrix includes outputs electrically coupled to the plurality of antenna elements.

[0098] Aspect 4. The wireless communication device according to any one of aspects 1 to 3, wherein the beamforming network is a Rotman lens.

[0099] Aspect 5. The wireless communication device according to any one of aspects 1 to 4 further includes: an antenna array including a plurality of antenna elements, wherein each antenna element of the plurality of antenna elements is coupled to the corresponding antenna port of the plurality of antenna ports.

[0100] Aspect 6. A wireless communication device according to any one of Aspects 1 to 5, wherein the multiple antenna elements are positioned in a circular formation with a predefined radius, wherein the corresponding position of each antenna element is associated with the orbital phase of the OAM beam.

[0101] Aspect 7. A wireless communication device according to any one of aspects 1 to 6, wherein the control circuit is configured to measure the misalignment of the OAM beam in communication with a remote wireless communication device.

[0102] Aspect 8. The wireless communication device according to any one of aspects 1 to 7, wherein the misalignment comprises one or more of off-axis misalignment, non-parallel misalignment and rotational mismatch alignment.

[0103] Aspect 9. A wireless communication device according to any one of Aspects 1 to 8, wherein the plurality of output phase shifters include varactor phase shifters, which are tunable using phase shift values ​​determined by the projection of each antenna element on the transmit-receive line to the corresponding antenna element of the remote wireless communication device.

[0104] Aspect 10. The wireless communication device according to aspect 9, wherein the control circuit is configured to measure the misalignment by calculating the alignment for each pair of antenna elements to determine a phase shift value for each phase shifter associated with the corresponding antenna element and antenna port.

[0105] Aspect 11. The wireless communication device according to any one of aspects 1 to 8, wherein the plurality of output phase shifters include passive phase shifters.

[0106] Aspect 12. A wireless communication device according to any one of aspects 1 to 8, wherein the multiple output phase shifters include a bidirectional phase shifter for providing reciprocal phase adjustment of a transmit OAM beam and a receive OAM beam in the OAM beam.

[0107] Aspect 13. The wireless communication device according to any one of Aspects 1 to 12 further includes: a transceiver circuit coupled to the multiple beam ports and configured to provide multiple OAM beams to the multiple beam ports, wherein each of the multiple beam ports receives signals of the multiple OAM beams associated with samples at a set orbital phase corresponding to each beam port.

[0108] Aspect 14. The wireless communication apparatus according to aspect 13, wherein the samples of the plurality of OAM beams are sampled at a rate sufficient to avoid phase aliasing between the OAM beams.

[0109] Aspect 15. A wireless communication apparatus according to any one of aspects 1 to 14, wherein the misalignment comprises a rotational mismatch, and wherein the control circuit is configured to adjust the differential phase of the signal for each beam port based on the rotational mismatch.

[0110] Aspect 16. A wireless communication device comprising: a Butler matrix comprising a plurality of antenna ports and a plurality of beam ports, wherein the plurality of antenna ports are positioned for transmitting an orbital angular momentum (OAM) beam; and a plurality of output phase shifters, wherein each output phase shifter is coupled to a corresponding antenna port among the plurality of antenna ports, and wherein phase shift values ​​for the plurality of output phase shifters are selected to correct for misalignment of the OAM beam.

[0111] Aspect 17. The wireless communication apparatus according to aspect 16, further comprising: a plurality of antenna elements coupled to each antenna port of the plurality of antenna ports.

[0112] Aspect 18. The wireless communication device according to any one of aspects 16 to 17, wherein the plurality of output phase shifters comprise passive phase shifters.

[0113] Aspect 19. A wireless communication device according to any one of aspects 16 to 17, wherein the plurality of output phase shifters include a bidirectional phase shifter for providing reciprocal phase adjustment of a transmit OAM beam and a receive OAM beam in the OAM beam.

[0114] Aspect 20. The wireless communication device according to any one of Aspects 16 to 19 further includes: a control circuit; and a transceiver circuit coupled to the control circuit and the multiple beam ports, wherein the transceiver circuit is configured to provide multiple OAM beams to the multiple beam ports, and wherein each of the multiple beam ports receives a corresponding control signal from the control circuit, wherein each corresponding control signal is associated with samples of the multiple OAM beams at a set orbital phase corresponding to each beam port.

[0115] Aspect 21. The wireless communication apparatus according to aspect 20, wherein the samples of the plurality of OAM beams are sampled to avoid phase aliasing between the OAM beams.

[0116] Aspect 22. A wireless communication device comprising: a transceiver circuit configured to generate signals for multiple orbital angular momentum (OAM) beams; a plurality of beam ports coupled to the transceiver circuit to transmit the multiple OAM beams; a plurality of antenna ports, wherein each antenna port is associated with a corresponding orbital phase of the multiple OAM beams; a plurality of three-decibels 90-degree couplers and internal phase shifters configured to couple the multiple beam ports to the multiple antenna ports; and a plurality of antenna elements positioned in a circular array, wherein each element is coupled to a corresponding antenna port among the multiple antenna ports.

[0117] Aspect 23. The wireless communication device according to Aspect 22 further includes: a control circuit coupled to the transceiver circuit, wherein the control circuit provides a control signal to the transceiver circuit, and wherein the control signal is associated with a set orbital phase for a corresponding beam port among the multiple beam ports.

[0118] Aspect 24. The wireless communication device according to aspect 23, wherein the control circuit is further configured to measure misalignment of the plurality of OAM beams in communication with a remote wireless communication device.

[0119] Aspect 25. The wireless communication device according to any one of aspects 22 to 24, wherein the misalignment comprises an off-axis misalignment.

[0120] Aspect 26. A wireless communication device according to any one of aspects 22 to 25, wherein the internal phase shifter comprises a bidirectional phase shifter for providing reciprocal phase adjustment of a transmit OAM beam and a receive OAM beam in the OAM beam.

[0121] Aspect 27. A wireless communication device according to any one of Aspects 22 to 26, wherein the internal phase shifter includes a varactor phase shifter, the varactor phase shifter being tunable using a phase shift value determined by a projection of each antenna element on a transmit-receive line to a corresponding antenna element of a remote wireless communication device, and wherein the control circuit is configured to measure the misalignment by calculating the alignment for each pair of antenna elements to determine a phase shift value for each phase shifter associated with the corresponding antenna element and antenna port.

[0122] Aspect 28. A method comprising: initiating, by a wireless communication device, a communication link with a remote wireless communication device, wherein the wireless communication device and the remote wireless communication device are configured to communicate using orbital angular momentum (OAM) beams, and wherein the wireless communication device includes a Butler matrix, an antenna array, and a plurality of phase shifters coupling antenna ports of the Butler matrix to corresponding elements of the antenna array; measuring, by the wireless communication device, a misalignment between the antenna array of the wireless communication device and the antenna array of the remote wireless communication device; selecting, by the wireless communication device, phase shift values ​​for the plurality of phase shifters to compensate for the misalignment; and using the phase shift values ​​to transmit a plurality of OAM beams between the wireless communication device and the remote wireless communication device.

[0123] Aspect 29. A method according to Aspect 28, wherein measuring the misalignment between the antenna array of the wireless communication device and the antenna array of the remote wireless communication device by the wireless communication device includes: receiving misalignment calculation results from the remote wireless communication device; and performing a set of misalignment measurements at the wireless communication device.

[0124] Aspect 30. A method according to any one of Aspects 28 to 29, wherein measuring the misalignment between the antenna array of the wireless communication device and the antenna array of the remote wireless communication device by the wireless communication device includes: performing calculations for rotational mismatch; performing calculations for off-axis misalignment; and performing calculations for non-parallel misalignment.

[0125] Aspect 31. A method for performing the operations according to any one of aspects 1 to 27.

[0126] Aspect 32. A wireless communication device, comprising: a unit for initiating a communication link with a remote wireless communication device using an orbital angular momentum (OAM) beam; a unit for measuring, by the wireless communication device, a misalignment between an antenna array of the wireless communication device and an antenna array of the remote wireless communication device; a unit for selecting, by the wireless communication device, phase shift values ​​for the multiple phase shifters to compensate for the misalignment; and a unit for transmitting multiple OAM beams between the wireless communication device and the remote wireless communication device using the phase shift values.

[0127] Aspect 33. An apparatus comprising a unit for performing the operation or configuration according to any one of aspects 1 to 30.

[0128] Aspect 34: A non-transitory computer-readable storage medium comprising instructions, which, when executed by a processing circuit of a device, causes the device to perform the operations or configurations according to any one of aspects 1 to 30.

Claims

1. A wireless communication device, comprising: a beamforming network comprising a plurality of antenna ports and a plurality of beam ports, wherein the plurality of antenna ports are coupled to transmit an orbital angular momentum (OAM) beam; a plurality of output phase shifters, wherein each output phase shifter is coupled to a corresponding antenna port of the plurality of antenna ports; and A control circuit is coupled to the plurality of output phase shifters and is configured to select phase shift values ​​for the plurality of output phase shifters to correct for misalignment of the OAM beam.

2. The wireless communication device according to claim 1, wherein: The beamforming network is a Butler matrix.

3. The wireless communication device according to claim 2, further comprising: A plurality of antenna elements, wherein the plurality of antenna ports of the Butler matrix are electrically coupled to the plurality of antenna elements via the plurality of output phase shifters.

4. The wireless communication device according to claim 1, wherein: The beamforming network is a Rotman lens.

5. The wireless communication device according to claim 1, further comprising: An antenna array includes a plurality of antenna elements, wherein each antenna element of the plurality of antenna elements is coupled to the corresponding antenna port of the plurality of antenna ports.

6. The wireless communication device according to claim 5, wherein: The plurality of antenna elements are positioned in a circular formation having a predefined radius, wherein a corresponding position of each antenna element is associated with an orbital phase of the OAM beam.

7. The wireless communication device according to claim 1, wherein: The control circuit is configured to measure the misalignment of the OAM beam in communication with a remote wireless communication device.

8. The wireless communication device according to claim 7, wherein: The misalignment includes one or more of an off-axis misalignment, a non-parallel misalignment, and a rotational mismatch alignment.

9. The wireless communication device according to claim 1, wherein: The plurality of output phase shifters include varactor phase shifters that are tunable using phase shift values ​​determined by the projection of each antenna element on the transmit-receive line to a corresponding antenna element of the remote wireless communication device.

10. The wireless communication device according to claim 9, wherein: The control circuit is configured to measure the misalignment by calculating an alignment for each pair of antenna elements to determine the phase shift value for each phase shifter associated with the corresponding antenna element and antenna port.

11. The wireless communication device according to claim 1, wherein: The plurality of output phase shifters include passive phase shifters.

12. The wireless communication device according to claim 1, wherein: The plurality of output phase shifters include a bidirectional phase shifter for providing reciprocal phase adjustment of a transmit OAM beam and a receive OAM beam in the OAM beams.

13. The wireless communication device according to claim 1, further comprising: A transceiver circuit is coupled to the plurality of beam ports and is configured to provide a plurality of OAM beams to the plurality of beam ports, wherein each of the plurality of beam ports receives signals of the plurality of OAM beams associated with samples at a set orbital phase corresponding to each beam port.

14. The wireless communication device according to claim 13, wherein: The samples of the plurality of OAM beams are sampled at a rate sufficient to avoid phase aliasing between the OAM beams.

15. The wireless communication device according to claim 1, wherein: The misalignment comprises a rotational mismatch, and wherein the control circuit is configured to adjust a differential phase of a signal for each beam port based on the rotational mismatch.

16. A wireless communication device, comprising: A Butler matrix comprising a plurality of antenna ports and a plurality of beam ports, wherein the plurality of antenna ports are positioned to transmit an orbital angular momentum (OAM) beam; and A plurality of output phase shifters, wherein each output phase shifter is coupled to a corresponding antenna port of the plurality of antenna ports, and wherein phase shift values ​​for the plurality of output phase shifters are configured to correct for misalignment of the OAM beam.

17. The wireless communication device according to claim 16, further comprising: A plurality of antenna elements are coupled to each antenna port of the plurality of antenna ports.

18. The wireless communication device according to claim 16, wherein: The plurality of output phase shifters include passive phase shifters.

19. The wireless communication device according to claim 16, wherein: The plurality of output phase shifters include a bidirectional phase shifter for providing reciprocal phase adjustment of a transmit OAM beam and a receive OAM beam in the OAM beams.

20. The wireless communication device of claim 16, further comprising: Control circuit; as well as a transceiver circuit coupled to the control circuit and the plurality of beam ports, wherein the transceiver circuit is configured to provide a plurality of OAM beams to the plurality of beam ports, and wherein each of the plurality of beam ports receives a corresponding control signal from the control circuit, wherein each corresponding control signal is associated with samples of the plurality of OAM beams at a set orbital phase corresponding to each beam port.

21. The wireless communication device according to claim 20, wherein: The samples of the plurality of OAM beams are sampled to avoid phase aliasing between the OAM beams.

22. A wireless communication device, comprising: transceiver circuitry configured to generate signals for a plurality of orbital angular momentum (OAM) beams; a plurality of beam ports coupled to the transceiver circuitry to transmit the plurality of OAM beams; a plurality of antenna ports, wherein each antenna port is associated with a corresponding orbital phase of the plurality of OAM beams; a plurality of three-decibels 90-degree couplers and internal phase shifters configured to couple the plurality of beam ports to the plurality of antenna ports; and A plurality of antenna elements are positioned in a circular array, wherein each element is coupled to a corresponding antenna port of the plurality of antenna ports.

23. The wireless communication device of claim 22, further comprising: A control circuit is coupled to the transceiver circuit, wherein the control circuit provides a control signal to the transceiver circuit, and wherein the control signal is associated with a set orbital phase for a corresponding beam port of the plurality of beam ports.

24. The wireless communication device according to claim 23, wherein: The control circuit is also configured to measure misalignment of the plurality of OAM beams in communication with a remote wireless communication device.

25. The wireless communication device according to claim 24, wherein: The misalignment includes an off-axis misalignment.

26. The wireless communication device according to claim 24, wherein: The internal phase shifter includes a bidirectional phase shifter for providing reciprocal phase adjustment of a transmit OAM beam and a receive OAM beam in the OAM beam.

27. The wireless communication device according to claim 24, wherein: The internal phase shifters include varactor phase shifters that are tunable using phase shift values ​​determined by a projection of each antenna element on a transmit-receive line onto a corresponding antenna element of a remote wireless communication device, and wherein the control circuit is configured to measure the misalignment by calculating an alignment for each pair of antenna elements to determine the phase shift value for each phase shifter associated with the corresponding antenna element and antenna port.

28. A method comprising: initiating, by a wireless communication device, a communication link with a remote wireless communication device, wherein the wireless communication device and the remote wireless communication device are configured to communicate using an orbital angular momentum (OAM) beam, and wherein the wireless communication device comprises a Butler matrix, an antenna array, and a plurality of phase shifters coupling antenna ports of the Butler matrix to corresponding elements of the antenna array; measuring, by the wireless communication device, a misalignment between the antenna array of the wireless communication device and the antenna array of the remote wireless communication device; selecting, by the wireless communication device, phase shift values ​​for the plurality of phase shifters to compensate for the misalignment; and A plurality of OAM beams are transmitted between the wireless communication device and the remote wireless communication device using the phase shift values.

29. The method according to claim 28, wherein: Measuring, by the wireless communication device, the misalignment between the antenna array of the wireless communication device and the antenna array of the remote wireless communication device comprises: receiving a misalignment calculation result from the remote wireless communication device; and A set of misalignment measurements are performed at the wireless communication device.

30. The method of claim 28, wherein: Measuring, by the wireless communication device, the misalignment between the antenna array of the wireless communication device and the antenna array of the remote wireless communication device comprises: performing calculations for rotational mismatch; performing calculations for off-axis misalignments; and Perform calculations for non-parallel misalignments.

Images