Beam management and antenna calibration in MIMO systems

Abstract

Millimeter-wave (mm-wave) and submillimeter-wave technologies, apparatus, and methods related to transceivers and receivers for wireless communications are described. Various aspects include a communications device including an antenna array and a processing circuit coupled to the antenna array. The processing circuit is configured to initialize a beam tracking algorithm based on received signals received at the antenna array, and antenna phases used in beam tracking are constrained by upper and lower phase limits to generate a beam tracking result. The processing circuit is further configured to generate a calibration vector based on the beam tracking result and receive subsequent transmissions using an adapted codebook based on the calibration vector.

Description

[Technical field]

[0001] Some aspects of the present disclosure pertain to wireless communication devices (e.g., mobile devices and base stations) that use antennas and antenna structures for communication of wireless signals. Some aspects of the present disclosure pertain to devices that operate according to a fifth generation (5G) wireless system. Some aspects of the present disclosure pertain to devices that operate according to a Wireless Gigabit Alliance (WiGig) (e.g., IEEE 802.11ad) protocol or other 802.x protocols. Some aspects of the present disclosure pertain to antenna array calibration in a multiple-input multiple-output (MIMO) system. Some aspects of the present disclosure pertain to an orbital angular momentum (OAM) based semi-open loop spatial multiplexing scheme for line-of-sight (LoS) MIMO communication. Some aspects of the present disclosure pertain to transmission mode switching for OAM and MIMO systems. [Background technology]

[0002] Various wireless communication technologies use beamforming to improve transmission and / or reception gain. Beam calibration is one way that the gain can be improved. However, calibration errors can be introduced through nonlinearities, heating, and noise in the system.

[0003] Furthermore, as the demand for connectivity increases and the available radio spectrum becomes congested, antenna arrays are being used to realize multiple-input multiple-output (MIMO) communication systems, which allow more degrees of freedom through spatial multiplexing and help operators meet the growing need for spectral efficiency. However, to obtain maximum multiplexing gain in these systems, the transmitters and receivers of the system must have knowledge of the channel conditions. This can be difficult to achieve when multiple antennas and strict latency constraints are present, because obtaining this knowledge requires large training overhead, large feedback overhead, and / or poor quality channel estimation per antenna element.

[0004] Furthermore, conventional wireless networks use various beamforming and spatial multiplexing techniques to maximize the channel capacity between the transmitter and receiver. In short-range wireless medium transmission usage scenarios (transmission distances less than 6 ft), WiGig (at 60 GHz), for example, uses beamforming to maximize the total throughput by maximizing the spatial gain of the signal from the transmitter to the receiver. Orbital Angular Momentum (OAM) is a spatial multiplexing scheme that can be used to increase the total channel capacity by transmitting and detecting mutually orthogonal OAM modes along the same propagation axis and physical channel. Some physical channel conditions are well suited to OAM, while other conditions are better suited to beamforming or other propagation schemes to achieve higher total channel capacity. [Brief description of the drawings]

[0005] The drawings are not necessarily drawn to scale, and in the drawings, like numerals may describe similar components in different views. Like numerals with different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various aspects discussed in the present document. [Figure 1] 1 illustrates an example user device in accordance with some aspects. [Figure 1A] 2 illustrates a millimeter wave system that can be used in conjunction with the device of FIG. 1, according to some embodiments. [Diagram 2] 1 illustrates an example base station radio head in accordance with some aspects. [Figure 3A] 1 illustrates an example millimeter wave communication circuit in accordance with some aspects. [Figure 3B] 3B illustrates an embodiment of an example transmit circuit shown in FIG. 3A, according to some embodiments. [Figure 3C] 3B illustrates an embodiment of an example transmit circuit shown in FIG. 3A, according to some embodiments. [Figure 3D] 3B illustrates an embodiment of the exemplary radio frequency circuit shown in FIG. 3A, according to some embodiments. [Figure 3E] 3B illustrates an embodiment of the example receiving circuit of FIG. 3A, according to some embodiments. [Figure 4] 3B illustrates an example usable RF circuit of FIG. 3A, in accordance with some embodiments. [Figure 5A] 1 illustrates an embodiment of an example radio front-end module (RFEM) in accordance with some embodiments. [Figure 5B] 1 illustrates an alternative aspect of an example wireless front-end module in accordance with some aspects. [Figure 6] 3 illustrates an example multi-protocol baseband processor usable in FIG. 1 or FIG. 2, in accordance with some aspects. [Figure 7] 1 illustrates an example mixed-signal baseband subsystem in accordance with some aspects. [Figure 8A] 1 illustrates an example digital baseband subsystem in accordance with some aspects. [Figure 8B] 1 illustrates an alternative aspect of an example baseband processing subsystem in accordance with some aspects. [Figure 9] 1 illustrates an exemplary digital signal processor subsystem in accordance with some aspects. [Figure 10A] 1 illustrates an example of an accelerator subsystem in accordance with some aspects. [Figure 10B] 1 illustrates an alternative exemplary accelerator subsystem in accordance with some aspects. [Figure 11] 1 illustrates an example fully digital mmWave receiver architecture in accordance with some aspects. [Figure 12] 1 illustrates beam boundaries for closed-loop beam tracking in accordance with some embodiments. [Figure 13] 1 illustrates a method for antenna array calibration in accordance with some aspects. [Figure 14] 1 illustrates a line-of-sight MIMO communication system in accordance with some aspects. [Figure 15] 1 illustrates a rectangular array of antenna elements according to some embodiments. [Figure 16] 1 illustrates a methodology for spatial multiplexing in accordance with some aspects. [Figure 17] 1 illustrates several OAM modes according to some embodiments. [Figure 18] 1 illustrates orbital angular momentum (OAM) mode selection and power allocation with water injection, in accordance with some aspects. [Figure 19A] 1 illustrates OAM mode selection based on signal-to-noise ratio (SNR) and distance between a transmitter and a receiver when one antenna element is used per OAM mode, in accordance with some aspects. [Figure 19B] 1 illustrates OAM mode selection based on signal-to-noise ratio (SNR) and distance between a transmitter and a receiver when a variable number of antenna elements are used for each OAM mode, in accordance with some aspects. [Figure 20] 1 illustrates a flowchart of a methodology for transmission mode switching in accordance with some aspects. [Figure 21] FIG. 1 illustrates a block diagram of a communication device, such as an evolved Node B (eNB), a new generation Node B (gNB), an access point (AP), a radio station (STA), a mobile station (MS), or a user equipment (UE), in accordance with some aspects. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] 1 illustrates an exemplary user device according to some aspects. The user device 100 may be a mobile device in some aspects and includes an application processor 105, a baseband processor 110 (also referred to as a baseband subsystem), a radio front end module (RFEM) 115, a memory 120, a connectivity subsystem 125, a near field communication (NFC) controller 130, an audio driver 135, a camera driver 140, a touch screen 145, a display driver 150, a sensor 155, a removable memory 160, a power management integrated circuit (PMIC) 165, and a smart battery 170.

[0007] In some aspects, the application processor 105 may include, for example, one or more central processing unit (CPU) cores and one or more cache memories, a low dropout voltage regulator (LDO), an interrupt controller, a serial interface such as SPI, I2C or a universal programmable serial interface subsystem, timer counters including a real-time clock (RTC), interval and watchdog timers, general purpose IO, a memory card controller such as SD / MMC or the like, a USB interface, a MIPI interface, and / or a Joint Test Access Group (JTAG) test access port.

[0008] In some aspects, the baseband processor 110 may be implemented as, for example, a soldered substrate containing one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board, and / or a multi-chip module containing two or more integrated circuits.

[0009] Applications of millimeter wave (mmWave) technology may include, for example, WiGig and upcoming 5G, although mmWave technology may be applicable to a variety of telecommunication systems. mmWave technology may be particularly attractive for short-range telecommunication systems. WiGig devices operate in the unlicensed 60 GHz band, whereas 5G mmWave is initially expected to operate in the licensed 28 GHz and 39 GHz bands. A block diagram of an exemplary baseband subsystem 110 and RFEM 115 in a mmWave system is shown in FIG. 1A.

[0010] 1A illustrates a mmWave system 100A that can be used in conjunction with the device 100 of FIG 1 according to some aspects of the disclosure. The system 100A includes two components: a baseband subsystem 110 and one or more radio front-end modules (RFEMs) 115. The RFEMs 115 can be connected to the baseband subsystem 110 by a single coaxial cable 190 that provides modulated intermediate frequency (IF) signals, DC power, clock signals, and control signals.

[0011] The baseband subsystem 110 is not shown in its entirety, but rather, FIG. 1A illustrates one implementation of an analog front end. It includes a transmitter (TX) section 191A with an upconverter 173 to an intermediate frequency (approximately 10 GHz in a current implementation), a receiver section 191B with a downconverter 175 from IF to baseband, and a control and multiplexing circuit 177 including a combiner for multiplexing / demultiplexing the transmit and receive signals onto a single cable 190. Additionally, a power tee circuitry 192 (including discrete components) is included on the baseband circuit board to provide DC power to the RFEM 115. In some aspects, the combination of the TX and RX sections may be referred to as a transceiver, to which one or more antennas or antenna arrays of the type described herein may be coupled.

[0012] The RFEM 115 may be a small circuit board that includes multiple printed antennas and one or more RF devices including upconversion / downconversion to millimeter-wave frequencies 174, power combiner / divider 176, programmable phase shifting 178 and multiple radio chains including power amplifiers (PA) 180, low noise amplifiers (LNA) 182, and control and power management circuits 184A and 184B. This arrangement may differ from Wi-Fi or cellular implementations, which typically integrate all RF and baseband functions into a single unit and have antennas connected only remotely via coaxial cables.

[0013] This architectural difference may be driven by very large power losses in the coaxial cable at millimeter wave frequencies. These power losses may reduce the transmit power at the antenna and reduce the receive sensitivity. To avoid this problem, in some embodiments, the PA 180 and LNA 182 may be moved to the RFEM 115 with an integrated antenna. Additionally, the RFEM 115 may include an upconversion / downconversion 174 so that the IF signal on the coaxial cable 190 may be at a lower frequency. Further system context for mmWave 5G devices, techniques, and features are discussed herein below.

[0014] 2 illustrates an exemplary base station or infrastructure equipment radio head according to some aspects. The base station radio head 200 can include one or more of an application processor 205, a baseband processor 210, one or more radio front-end modules 215, a memory 220, a power management integrated circuit (PMIC) 225, a power tee circuit 230, a network controller 235, a network interface connector 240, a satellite navigation receiver (e.g., a GPS receiver) 245, and a user interface 250.

[0015] In some aspects, the application processor 205 may include one or more CPU cores and one or more cache memories, a low dropout voltage regulator (LDO), an interrupt controller, a serial interface such as an SPI, I2C or a universal programmable serial interface, a real-time clock (RTC), timer counters including interval and watchdog timers, general purpose IO, a memory card controller such as SD / MMC or the like, a USB interface, a MIPI interface, and a Joint Test Access Group (JTAG) test access port.

[0016] In some aspects, the baseband processor 210 may be implemented as, for example, a soldered substrate containing one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board, or a multi-chip subsystem containing two or more integrated circuits.

[0017] In some embodiments, memory 220 may include one or more of volatile memory, including dynamic random access memory (DRAM) and / or synchronous DRAM (SDRAM), and non-volatile memory, including high speed electrically erasable memory (commonly referred to as flash memory), phase change random access memory (PRAM), magnetoresistive random access memory (MRAM), and / or three-dimensional cross-point memory. Memory 220 may be implemented as one or more of a soldered packaged integrated circuit, a socketed memory module, and a plug-in memory card.

[0018] In some aspects, the power management integrated circuit 225 can include one or more of a voltage regulator, a surge protector, a power alarm detection circuit, and one or more backup power sources such as a battery or a capacitor. The power alarm detection circuit can detect one or more of a brownout (under-voltage) condition and a surge (over-voltage) condition.

[0019] In some aspects, the power tee circuit 230 can provide power drawn from a network cable. The power tee circuit 230 can provide both power and data connectivity to the base station radio head 200 using a single cable.

[0020] In some aspects, the network controller 235 can provide connectivity to a network using a standard network interface protocol, such as Ethernet. Network connectivity may be provided using a physical connection that is one of electrical (commonly referred to as copper interconnects), optical, or wireless.

[0021] In some aspects, satellite navigation receiver 245 may include circuitry to receive and decode signals transmitted by one or more navigation satellite constellations, such as global positioning system (GPS), Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS), Galileo, and / or BeiDou. Receiver 245 may provide data to application processor 205 that may include one or more of positioning data or time data. The time data may be used by application processor 205 to synchronize operation with other wireless base stations or infrastructure equipment.

[0022] In some embodiments, the user interface 250 may include one or more buttons, which may include a reset button, and one or more indicators, such as LEDs and a display screen.

[0023] FIG. 3A illustrates an example millimeter wave communication circuit according to some aspects, FIGs. 3B and 3C illustrate aspects of a transmit circuit shown in FIG. 3A according to some aspects, FIG. 3D illustrates aspects of a radio frequency circuit shown in FIG. 3A according to some aspects, and FIG. 3E illustrates aspects of a receive circuit in FIG. 3A according to some aspects. The millimeter wave communication circuit 300 shown in FIG. 3A may alternatively be grouped according to function. The components shown in FIG. 3A are provided here for purposes of explanation and may include other components not shown in FIG. 3A.

[0024] The millimeter wave communication circuit 300 may include a protocol processing circuit 305 (or processor), or other processing means. The protocol processing circuit 305 may implement, among other things, one or more of medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), radio resource control (RRC), and non-access stratum (NAS) functions. The protocol processing circuit 305 may include one or more processing cores for executing instructions and one or more memory structures for storing program and data information.

[0025] The millimeter wave communication circuit 300 may further include a digital baseband circuit 310. The digital baseband circuit 310 may implement physical layer (PHY) functions, including one or more of hybrid automatic repeat request (HARQ) functions, scrambling and / or descrambling, coding and / or decoding, layer mapping and / or demapping, modulation symbol mapping, received symbol and / or bit metric determination, multi-antenna port pre-coding and / or decoding, which may include one or more of space-time, space-frequency, or spatial coding, reference signal generation and / or detection, preamble sequence generation and / or decoding, synchronization sequence generation and / or detection, control channel signal blind decoding, and other related functions.

[0026] The millimeter wave communication circuit 300 may further include a transmit circuit 315, a receive circuit 320, and / or an antenna array circuit 330. The millimeter wave communication circuit 300 may further include an RF circuit 325. In some aspects, the RF circuit 325 may include one or more parallel RF chains for transmitting and / or receiving. Each of the RF chains may be connected to one or more antennas of the antenna array circuit 330.

[0027] In some aspects, the protocol processing circuit 305 may include one or more instances of a control circuit. The control circuit may provide control functions for one or more of the digital baseband circuit 310, the transmit circuit 315, the receive circuit 320, and / or the RF circuit 325.

[0028] 3B and 3C illustrate aspects of the transmit circuitry shown in FIG. 3A, according to some aspects. The transmit circuitry 315 shown in FIG. 3B may include one or more of a digital-to-analog converter (DAC) 340, an analog baseband circuitry 345, an upconversion circuitry 350, and / or a filtering and amplifying circuitry 355. The DAC 340 may convert a digital signal to an analog signal. The analog baseband circuitry 345 may perform a number of functions, as described below. The upconversion circuitry 350 may upconvert a baseband signal from the analog baseband circuitry 345 to an RF frequency (e.g., a millimeter wave frequency). The filtering and amplifying circuitry 355 may filter and amplify the analog signal. Control signals may be provided between the protocol processing circuitry 305 and one or more of the DAC 340, the analog baseband circuitry 345, the upconversion circuitry 350, and / or the filtering and amplifying circuitry 355.

[0029] 3C may include a digital transmit circuit 365 and an RF circuit 370. In some aspects, a signal from the filtering and amplification circuit 355 may be provided to the digital transmit circuit 365. As described above, control signals may be provided between the protocol processing circuit 305 and one or more of the digital transmit circuit 365 and the RF circuit 370.

[0030] 3D illustrates an embodiment of the radio frequency circuitry shown in FIG. 3A, according to some embodiments. The radio frequency circuitry 325 can include one or more instances of the radio chain circuitry 372, which in some embodiments can include one or more filters, power amplifiers, low noise amplifiers, programmable phase shifters, and power supplies.

[0031] The radio frequency circuitry 325 may also include a power combining and distribution circuitry 374 in some aspects. In some aspects, the power combining and distribution circuitry 374 may operate bidirectionally, such that the same physical circuitry may be configured to operate as a power divider when the device is transmitting and as a power combiner when the device is receiving. In some aspects, the power combining and distribution circuitry 374 may include one or more wholly or partially separate circuits to perform power distribution when the device is transmitting and power combining when the device is receiving. In some aspects, the power combining and distribution circuitry 374 may include passive circuits including one or more bi-directional power dividers / combiners arranged in a tree. In some aspects, the power combining and distribution circuitry 374 may include active circuits including amplifier circuits.

[0032] In some aspects, the radio frequency circuitry 325 can be coupled to the transmit circuitry 315 and receive circuitry 320 of FIG. 3A. The radio frequency circuitry 325 may be coupled to the transmit circuitry 315 and receive circuitry 320 via one or more radio chain interfaces 376 and / or a combined radio chain interface 378. In some aspects, the one or more radio chain interfaces 376 can provide one or more interfaces for one or more receive or transmit signals, each associated with a single antenna structure. In some aspects, the combined radio chain interface 378 can provide a single interface for one or more receive or transmit signals, each associated with a group of antenna structures.

[0033] FIG. 3E illustrates an embodiment of the receiving circuit in FIG. 3A according to some embodiments. The receiving circuit 320 can include one or more of the parallel receiving circuits 382 and / or one or more of the combined receiving circuits 384. In some embodiments, the one or more parallel receiving circuits 382 and the one or more combined receiving circuits 384 can include one or more intermediate frequency (IF) downconversion circuits 386, IF processing circuits 388, baseband downconversion circuits 390, baseband processing circuits 392, and analog-to-digital converter (ADC) circuits 394. As used herein, the term "intermediate frequency" refers to a frequency to which a carrier frequency (or a frequency signal) is shifted in an intermediate step in transmission, reception, and / or signal processing. The IF downconversion circuit 386 can convert the received RF signal to an IF. The IF processing circuit 388 can process the IF signal, for example, via filtering and amplification. The baseband downconversion circuit 390 can convert the signal from the IF processing circuit 388 to baseband. The baseband processing circuitry 392 may process the baseband signals, for example, via filtering and amplification. The ADC circuitry 394 may convert the processed analog baseband signals to digital signals.

[0034] 4 illustrates an example RF circuit of FIG. 3A, according to some aspects. In one aspect, the RF circuit 325 of FIG. 3A (denoted using reference number 425 in FIG. 4) can include one or more of an IF interface circuit 405, a filtering circuit 410, an up-conversion and down-conversion circuit 415, a synthesizer circuit 420, a filtering and amplification circuit 424, a power combining and distribution circuit 430, and a radio chain circuit 435.

[0035] 5A and 5B illustrate an embodiment of a radio front-end module usable for the circuitry shown in FIGS. 1 and 2 according to some embodiments. FIG. 5A illustrates one embodiment of a radio front-end module (RFEM) according to some embodiments. The RFEM 500 incorporates a millimeter-wave RFEM 505 and one or more greater than 6 gigahertz radio frequency integrated circuits (RFICs) 515 and / or one or more sub-six gigahertz RFICs 522. In this embodiment, the one or more sub-six gigahertz RFICs 515 and / or the one or more sub-six gigahertz RFICs 522 may be physically separate from the millimeter-wave RFEM 505. The RFICs 515 and 522 may include connections to one or more antennas 520. The RFEM 505 may include multiple antennas 510.

[0036] 5B illustrates an alternative embodiment of a radio front-end module in accordance with some embodiments. In this embodiment, both millimeter wave and sub-6 gigahertz radio functions may be implemented within the same physical radio front-end module (RFEM) 530. The RFEM 530 may incorporate both a millimeter wave antenna 535 and a sub-6 gigahertz antenna 540.

[0037] Figure 6 illustrates a multi-protocol baseband processor 600 usable in the systems and circuitry illustrated in Figure 1 or Figure 2, according to some aspects. In one aspect, the baseband processor can include one or more digital baseband subsystems 640A, 640B, 640C, 640D, also collectively referred to herein as digital baseband subsystems 640.

[0038] In one aspect, one or more of the digital baseband subsystems 640A, 640B, 640C, 640D may be coupled to one or more of the CPU subsystem 670, the audio subsystem 675, and the interface subsystem 680 via an interconnect subsystem 665. In one aspect, one or more of the digital baseband subsystems 640 may be coupled to one or more of the digital baseband interfaces 660A, 660B, and each of the mixed-signal baseband subsystems 635A, 635B via an interconnect subsystem 645.

[0039] In one aspect, the interconnect subsystems 665 and 645 may each include one or more of a bus point-to-point connection and a network-on-chip (NOC) fabric, respectively. In one aspect, the audio subsystem 675 may include one or more of digital signal processing circuitry, buffer memory, program memory, speech processing accelerator circuitry, data converter circuitry such as analog-to-digital converter circuitry and digital-to-analog converter circuitry, and analog circuitry including one or more of amplifiers and filters.

[0040] 7 illustrates an example of a mixed-signal baseband subsystem 700 in accordance with some aspects. In one aspect, the mixed-signal baseband subsystem 700 can include one or more of an IF interface 705, an analog IF subsystem 710, a downconverter and upconverter subsystem 720, an analog baseband subsystem 730, a data converter subsystem 735, a synthesizer 725, and a control subsystem 740.

[0041] Figure 8A illustrates a digital baseband processing subsystem 801 according to some aspects. Figure 8B illustrates an alternative aspect of a digital baseband processing subsystem 802 according to some aspects.

[0042] In the embodiment of FIG. 8A, the digital baseband processing subsystem 801 may include one or more of each of the digital signal processor (DSP) subsystems 805A, 805B, ... 805N, the interconnect subsystem 835, the boot loader subsystem 810, the shared memory subsystem 815, the digital I / O subsystem 820, and the digital baseband interface subsystem 825.

[0043] In the embodiment of FIG. 8B, the digital baseband processing subsystem 802 may include one or more of each of the accelerator subsystems 845A, 845B, ... 845N, buffer memories 850A, 850B, ... 850N, interconnect subsystem 835, shared memory subsystem 815, digital I / O subsystem 820, controller subsystem 840, and digital baseband interface subsystem 825.

[0044] In one aspect, the boot loader subsystem 810 may include digital logic circuitry configured to perform configuration of a program memory and an execution state associated with each of the one or more DSP subsystems 805. Configuring the program memory of each of the one or more DSP subsystems 805 may include loading executable program code from storage external to the digital baseband processing subsystems 801 and 802. Configuring the execution state associated with each of the one or more DSP subsystems 805 may include one or more of the following steps: setting a state of at least one DSP core that may be incorporated in each of the one or more DSP subsystems 805 to a state in which it is not executing; and setting a state of at least one DSP core that may be incorporated in each of the one or more DSP subsystems 805 to a state in which it begins executing program code beginning from a predetermined memory location.

[0045] In one aspect, the shared memory subsystem 815 may include one or more of read-only memory (ROM), static random access memory (SRAM), embedded dynamic random access memory (eDRAM), and / or non-volatile random access memory (NVRAM).

[0046] In one embodiment, the digital I / O subsystem 820 is an Inter-Integrated Circuit (I2C) 2 The digital I / O subsystem 820 may include one or more of a serial interface, such as a serial peripheral interface (SPI), serial peripheral interface (SPI), or other one-, two-, or three-wire serial interface, a parallel interface, such as a general purpose input / output (GPIO), a register access interface, and a direct memory access (DMA). In one aspect, a register access interface implemented in the digital I / O subsystem 820 may enable a microprocessor core external to the digital baseband processing subsystem 801 to read and / or write one or more of the control and data registers and memory. In one aspect, DMA logic implemented in the digital I / O subsystem 820 may enable the transfer of contiguous blocks of data between memory locations, including memory locations internal and external to the digital baseband processing subsystem 801.

[0047] In one aspect, the digital baseband interface subsystem 825 can provide for the transfer of digital baseband samples between the baseband processing subsystem and mixed-signal baseband or radio frequency circuitry external to the digital baseband processing subsystem 801. In one aspect, the digital baseband samples transferred by the digital baseband interface subsystem 825 can include in-phase and quadrature (I / Q) samples.

[0048] In one aspect, the controller subsystem 840 may include one or more of control and status registers and each of the control state machines. In one aspect, the control and status registers may be accessed via a register interface and may provide one or more of starting and stopping the operation of the control state machine, resetting the control state machine to a default state, configuring any processing functions, and / or configuring the generation of interrupts, and reporting the status of the operation. In one aspect, each of the one or more control state machines may control the operation sequence of each of the one or more accelerator subsystems 845. Examples of implementations of both FIG. 8A and FIG. 8B may exist within the same baseband subsystem.

[0049] FIG. 9 illustrates a digital signal processor (DSP) subsystem 900 in accordance with some aspects.

[0050] In one aspect, the DSP subsystem 900 may include one or more of the following: a DSP core subsystem 905, a local memory 910, a direct memory access (DMA) subsystem 915, accelerator subsystems 920A, 920B...920N, an external interface subsystem 925, a power management circuit 930, and an interconnect subsystem 935.

[0051] In one aspect, the local memory 910 may include one or more of each of a read-only memory, a static random access memory, or an embedded dynamic random access memory.

[0052] In one aspect, the DMA subsystem 915 can provide register and control state machine circuitry adapted to transfer blocks of data between memory locations, including memory locations internal and external to the DSP subsystem 900.

[0053] In one aspect, external interface subsystem 925 can provide access by a microprocessor system external to DSP subsystem 900 to one or more of memory, control registers, and status registers that may be implemented within DSP subsystem 900. In one aspect, external interface subsystem 925 can provide transfer of data between local memory 910 and storage devices external to DSP subsystem 900 under the control of one or more of DMA subsystem 915 and DSP core subsystem 905.

[0054] 10A illustrates an example of an accelerator subsystem 1000 according to some embodiments. FIG. 10B illustrates an example of an accelerator subsystem 1000 according to some embodiments.

[0055] In one aspect, the accelerator subsystem 1000 may include one or more of a control state machine 1005, a control register 1010, a memory interface 1020, a scratch pad memory 1025, computation engines 1030A...1030N, and each of data flow interfaces 1035A, 1035B.

[0056] In one aspect, the control registers 1010 can configure and control the operation of the accelerator subsystem 1000, including one or more of: enabling or disabling an operation using an enable register bit, stopping an operation in progress by writing to a halt register bit, providing parameters for configuring computational operations, providing memory address information for identifying the location of one or more control and data structures, configuring the generation of interrupts, or other control functions.

[0057] In one aspect, the control state machine 1005 can control the sequence of operations of the accelerator subsystem 1000 .

[0058] Method of antenna array calibration for MIMO receivers Wireless chip-to-chip communications can include multiple antenna systems at the receiver. In such communications, the aggregate data rate requirements can be significant, and high frequencies (e.g., the terahertz range) are often used in such communications. However, multiple antenna systems can have calibration errors due to heating or nonlinearity and noise in the system. The resulting calibration errors affect beamforming performance, which in turn contributes to increased interference, degradation of the signal-to-noise ratio (SNR), and reduced data rates.

[0059] Some methods for calibrating multiple antenna systems utilize pre-calibrated beamforming vectors, however, due to thermal heating or changes in antenna electrical properties, the pre-calibrated codebook values ​​may not be valid, leading to increased interference.

[0060] Some other methods for calibrating multiple antenna systems may include closed-loop beam tracking methods that blindly adapt the beam direction according to the spatial correlation of the received signal to maximize the received signal power. However, closed-loop beam tracking may result in beamforming vectors with fairly high side lobes that capture power from interference and cause a significant loss in block error rate. The loss may increase depending on the interference direction and strength. Furthermore, multi-beam tracking methods may be overly complex.

[0061] Methods, systems, and apparatus according to some aspects provide low-complexity blind digital beam calibration for multiple antenna systems that may otherwise exhibit the above-mentioned calibration errors. Methods according to some aspects can maximize beamforming gain by mitigating antenna array phase errors as described herein. Blind beam calibration can improve communication latency because pilot sequences are not used for calibration and calibration can be performed based on any communication signal in the channel. In contrast, other types of calibration require periodic transmission of pilot sequences. Furthermore, digital beamforming has the advantage of enabling beam calibration in the digital domain parallel to the data path. Methods according to some aspects can be performed in a fully digital receiver such as that shown in FIG. 11.

[0062] 11 illustrates an example fully digital mmWave receiver architecture 1100 in accordance with some aspects. Compression is performed in the spatial domain, and N r The antennas 1112 are N r The input 1114 is fed through an ADC 1106 to provide a complex signal y 1114. Blind beam calibration is performed by a beam calibration circuit 1118 using the input 1114 and providing a beamforming vector 1120 to a compression circuit 1108, which then provides a beamforming output 1116 to the baseband processing circuit 1110.

[0063] An optimization metric for beam calibration, in some aspects, may include maximizing received signal power by maximizing over a calibration vector (see equation (1) below). For a given number of I / O interface links M, a method according to an aspect tracks the M beams that provide the maximum received power in the time domain.

number

[0064] The cost function maximizes the received signal power after beamforming. The method according to the proposed aspect uses time domain samples without the requirement of time and frequency offset correction. This blind approach works in both frequency and time domains. In order to reduce the high side lobes mentioned above, constraints are imposed on the closed loop beam tracking method according to the aspects described herein.

[0065] The signal received at the kth antenna is given according to equation (2).

number

[0066] In vector form this can be written as:

number

[0067] h can be expressed as follows:

number

number

[0068] Given a beamforming matrix D, the best beam direction d in terms of received signal power is best(the highest beamforming gain) can be selected from D. The phase values ​​of the best beam can be shown as follows for a uniform linear array with N antennas:

number

number

[0069] The closed-loop beam tracking algorithm is implemented as follows.

number

[0070] Weight w k * is determined by an algorithm that maximizes the output power of the beamforming signal r(t).

number

[0071] One example of such an algorithm is to use an Equal Gain Combining technique that maximizes the output power.

number

number

[0072] As described above, after performing closed-loop calibration, the phase value converges to the value that maximizes the received signal power. In essence, this algorithm solves for phase calibration errors in the receiver path. k is updated at each sample time to find the best phase for each antenna.

[0073] After finding the calibrated beamforming vector w, the difference between the phase of the calibrated beam and the original phase of the uncalibrated beam (e.g., the “calibration error”) is calculated to find c, which is used in equation (1).

number

[0074] The above closed-loop algorithm maximizes the beamforming gain by adjusting each antenna element phase. The same calibration error calculated in equation (13) is used to calibrate the entire codebook (e.g., for each beam), because the calibration error is common to all beam directions. In other words, since each beam direction uses the same antenna array, each beam direction should have the same calibration error, because all antennas in the antenna array are subject to the same thermal, noise, and other conditions. Furthermore, if each beam were calibrated differently, orthogonality would be lost and interference would increase.

[0075] FIG. 13 illustrates a method 1300 for antenna array calibration according to some aspects. Some operations of the method 1300 may be performed by a processing circuit, such as the compression circuit 1108 (FIG. 11) or the baseband processor 110 (FIG. 1). The method 1302 may begin with the processing circuit determining which best beam direction of a matrix of beamforming directions is best, the "best" beam direction being the beam direction for which the received power is maximized. In some aspects, the best beam direction may be determined based on Equations (2)-(6) as previously described herein. In some aspects, the beamforming direction may be determined periodically or upon noticing degradation in communication.

[0076] The example method 1300 continues with operation 1304, where the processing circuitry initializes a phase constraint. In some aspects, the phase constraint may be defined as described above with reference to equations (7)-(8), as previously described herein. The example method 1300 continues with operation 1306, where the processing circuitry performs closed-loop beam tracking of the received signal, e.g., according to equations (9)-(12), as previously described herein.

[0077] The exemplary method 1300 continues with operations 1308 and 1310, where the processing circuitry determines a difference between the phase of the calibrated beam and the original phase of the uncalibrated beam to determine a calibration error according to equation (13) previously described herein. Once the calibration error is determined, the codebook can be adjusted for subsequent communications based on the calibration error. As previously described herein, the same calculated calibration error is used to calibrate the entire codebook to limit interference between beams.

[0078] Orbital Angular Momentum (OAM)-Based Semi-Open-Loop Spatial Multiplexing Scheme for Line-of-Sight (LoS) MIMO Communications Antenna arrays can be used to realize MIMO communication systems, which allow more degrees of freedom through spatial multiplexing and help operators meet the growing need for spectral efficiency. In long-range line-of-sight (LoS) communications, the channel matrix is ​​of rank 1. In long-range LoS, beamforming on a single data stream can be applied to provide coverage.

[0079] In short-range LoS (chip-to-chip communication is an example of short-range communication, but the aspect is not limited thereto), the channel matrix has a high rank (the actual rank depends on the specific distance and the number of antenna elements) and a higher multiplexing gain can be achieved. The maximum distance at which this multiplexing gain can be achieved is determined by the size of the transmitter and receiver apertures and the wavelength. In high-frequency applications such as terahertz communication, this "short" distance becomes practically applicable.

[0080] To achieve maximum multiplexing gain from the channel, transmitter and receiver circuits in current systems acquire detailed knowledge of the channel matrix (CSI). Acquiring such knowledge can be difficult when multiple antennas and strict latency constraints exist because it requires large training overhead, large feedback overhead, and / or low quality channel estimation per antenna element. Apparatus, systems, and methods according to some aspects provide a scheme that requires no full knowledge of the channel itself, but only feedback for simple sector sweeping before communication. For semi-open-loop MIMO multiplexing, blind power allocation is performed on pre-computed orthogonal streams. In an aspect, power can be allocated based on Orbital Angular Momentum (OAM) mode. Because the channel is LoS (e.g., no or little scattering), multiplexing gain can be provided in a semi-open-loop manner based on the geometries of the transmitter and receiver arrays.

[0081] A method according to an aspect provides a multiplexing scheme for MIMO LoS systems. The scheme is applicable to any communication range, but works best at short distances and provides significant multiplexing gain over standard beamforming. MIMO beamforming according to an aspect utilizes a fixed transmit-receive antenna array structure. The method according to an aspect does not estimate the channel for each antenna, thereby reducing latency. The method according to an aspect optimizes spatial multiplexing beamforming by using sector sweeping to select one or more of the beam directions, which can increase the SNR. Furthermore, sector sweeping can easily find beamforming when the transmitter and receiver are not aligned.

[0082] FIG. 14 illustrates a line-of-sight MIMO communications system 1400 in accordance with some aspects. The system 1400 includes a transmitter antenna array 1402 and a receiver antenna array 1404. Each array 1402, 1404 includes multiple antenna elements on a plane. The arrays 1402, 1404 are assumed to be omnidirectional with a gain of 0 dBi. However, aspects are not limited in this respect and methods in accordance with aspects can be extended to allow for any gain and directivity pattern of the antenna. The transmitter antenna array 1402 has N antenna elements 1406 arranged at positions {(x i ,y i )} i=1 N For example, a uniform linear array has, for some separation Δ, (x i ,y i )=(iΔ,0), i=1,...,N. Similarly, the receiver antenna array 1404 has M antenna elements 1408 positioned

number

[0083] The method according to the embodiment includes a pre-calculation phase, in which the virtual MIMO channel matrix

number

number

number

[0084] The channel matrix defined above is normalized, and the actual channel matrix is

number

[0085] The pre-computed distance z is a design parameter that should be large enough to capture the correct characteristics of the channel. In general, the closer z is to the actual communication range, the better the scheme will perform. However, the actual communication range is usually not known in advance. As a rule of thumb,

number

[0086]

number

[0087] Quantity D TX and D. RX are the aperture diameters of the transmitter antenna array 1402 and the receiver antenna array 1404, respectively. i ,y i )} i=1 N The diameter of the antenna array given by is defined as:

number

[0088]

number

number

number

number

number

number

[0089] In an aspect, the pre-computation phase is performed only once and is part of the communication system design. The results are then stored in the transmitter and receiver (or only partial results, depending on the embodiment). The communication scheme described below uses eigenvectors in U and V corresponding to the OAM modes and singular values ​​Σ (computed for a "virtual" channel) to multiplex several information streams without the need to know the actual channel matrix H. This means that

number

[0090] In the later communication phase, the transmitter antenna array 1402 and the receiver antenna array 1404 follow a protocol to find the desired TX and RX beam directions according to the array orientation. For example, for beam alignment, codebook-based beamforming and exhaustive transmit and receiver search can be followed, in which the transmitter performs sector sweeping to find the best direction of transmission at the receiver (while the receiver listens in all directions). The receiver then reports the best transmission direction to the transmitter. The receiver then performs sector sweeping to find the best direction of reception (the transmitter transmits in the direction just found in the transmitter sector sweep). The receiver sector sweeping can be done in virtually zero time, assuming the receiver has a full digital millimeter wave architecture.

[0091] Once sector sweeping and beamforming are performed, communication can occur in one of at least two ways. In a first communication method according to an aspect, a transmitter (e.g., transmitter section 191A (FIG. 1A)) multiplexes r independent data streams using a precoding matrix V, with uniform power allocation across all r streams. Thus, a receiver (e.g., receiver section 191B (FIG. 1A)) applies U to the received signal. * Post-processing is performed by multiplying r by the “virtual” channel matrix found in the pre-computation phase described earlier in this specification.

number

[0092] The effective channel matrix is ​​of dimension r×r, which is significantly smaller than the dimension M×N of the actual channel matrix. The receiver performs channel estimation based on this smaller effective channel matrix and later decodes the signal using, for example, minimum mean-square error (MMSE) subsequent interference cancellation (SIC).

[0093] Alternatively, in a second communication method according to another aspect, water-filling (allocating power to multiple channels under a constant total power) is performed to perform power allocation without the need to first perform channel estimation. The receiver measures the SNR using the selected TX and RX beams determined from sector sweeping. The SNR can be approximated by the following formula:

number

[0094] The SNR measurement obtained in (19) is fed back to the transmitter. In practice, the SNR can be measured on reference / preamble symbols known between TX and RX. According to this second communication method, H is approximated for some scalar ρ as follows:

number

number

number

[0095] The approximations are found in the precomputation phase such that the singular values ​​approximate the eigenvalues ​​of H.

number

number

number

number

[0096] The transmitter uses the calculated power allocation to multiplex r (or less, depending on the water-filling result) data streams using the matrix V found in the pre-computation phase. The receiver can apply MMSE-SIC demultiplexing using the matrix U.

[0097] 16 illustrates a method 1600 for spatial multiplexing according to some aspects. In an aspect, the method 1600 can be performed by a processing circuit (e.g., the baseband processor 110 (FIG. 1), the transmitter section 191A (FIG. 1A), the receiver section 191B (FIG. 1A), etc.).

[0098] Method 1600 begins at operation 1602, where a processing circuit performs a transmit sector sweep to determine a best transmit direction. Method 1600 may continue with operation 1604, where a processing circuit performs a receive sector sweep based on the best transmit direction. Operations may also include MIMO detection of multiple streams after the receive sector sweeping.

[0099] Method 1600 may continue with operation 1606, where the processing circuitry measures the signal-to-noise ratio at the receiver using the best transmit direction and the best receiver direction. Operation 1606 may proceed according to equation (19) and the accompanying description provided earlier herein.

[0100] Method 1600 may continue with operation 1608, where the processing circuitry calculates a power allocation for a subsequent transmission based on the signal-to-noise ratio. Operation 1608 may proceed in accordance with equations (20)-(22) and the accompanying description. The power allocation may be performed using a water-filling algorithm, which may be applied on a multiplexed stream having an adaptive number of streams. The number of streams may also be based on the SNR. Power may be allocated to active streams, which may be determined based on the SNR.

[0101] The method 1600 may further include other operations such as generating a reduced channel matrix based on the geometry of the communication device's transmit and receive antenna arrays in accordance with Equations (14)-(18) and accompanying description provided herein above. An approximation of the full channel matrix may be generated based on the reduced channel matrix. Multiple data streams may be multiplexed based on the reduced channel matrix. A precoder for multiplexing may include eigenvectors of the channel extracted from the reduced channel matrix. The reduced channel matrix may be based on a selected distance between the transmit and receive antenna arrays. The distance may be estimated based on a detected SNR at the receiver.

[0102] Method for transmitting mode switching for OAM and MIMO systems Orbital Angular Momentum (OAM) is an electromagnetic wave phenomenon in which the wavefront propagates with a helical phase front with a phase shift of 2πm, where m is an integer representing the mode order. Various research activities have demonstrated that OAM beams of different orders are orthogonal and therefore ideally do not interfere with each other. This means, for example, that an OAM beam of order m=0 does not interact with other OAM mode orders, even with all modes essentially propagating simultaneously along the same axis in the same physical "free space" channel. However, in practice, due to engineering limitations and channel impairments, OAM modes may experience crosstalk due to mode generation artifacts as well as channel multipath and reflection effects. Despite these non-idealities, OAM is a good candidate transmission technology for high-throughput data links where line-of-sight exists between the transmitter and receiver, especially for short-range communications such as WiGig.

[0103] OAM is also preferred in LoS scenarios where multipath is poor because mode crosstalk is minimal, increasing channel capacity in that case compared to conventional spatially multiplexed line-of-sight (e.g., conventional MIMO).

[0104] FIG. 17 illustrates several OAM modes according to some aspects. Left column 1710 illustrates OAM modes 1710a, 1710b, ..., 1710e propagating in free space. A spiral propagation pattern of the wavefront can be observed. Center column 1720 illustrates a phase profile of a planar cross section of the wavefront of each mode. Right column 1730 illustrates an amplitude profile for each of the propagating OAM wavefronts of each mode. To generate and receive OAM modes in wireless communication, a suitable wireless system communication architecture addresses OAM antenna topologies, mode generation / reception topologies, and multi-OAM signaling. For example, an OAM antenna topology can include a concentric antenna array for generating multiple OAM modes using patch antenna elements according to some aspects. In some examples, concentric rings of a circular antenna array can generate separate OAM modes. Each concentric antenna array ring generates a different mode, and the total number of modes desired dictates the number of concentric rings used. Each of the concentric antenna array rings can be made of any type of antenna element. For example, a square patch antenna may be used. However, circular or other geometry patch antennas may be used. Furthermore, a patch antenna is not a requirement as any type of antenna may be used. Furthermore, some embodiments may use other than concentric ring antennas.

[0105] Similar to conventional wireless communication systems, OAM communication systems include conventional system blocks such as baseband components for digital signal processing, RF front-end components including RF elements such as filters, amplifiers, local oscillators, mixers, and other components, and antenna systems.

[0106] The method of implementation of the OAM system depends on the OAM mode transmission approach to determine the system architecture. The OAM communication system can be used to transmit separate data streams over different OAM modes or one single data stream over multiple modes to provide spatial diversity and mitigate fading channels caused by multipath problems. Furthermore, the system may be adaptable to configurations between these two transmission types. In one embodiment, n data streams can be mapped to n modes, which may be referred to as full multiplexing. In another embodiment, less than n data streams can be mapped to n OAM modes, which may provide partial diversity and partial multiplexing. In yet another embodiment, one data stream can be mapped to n modes, which may be referred to as full diversity.

[0107] Multiplexing a smaller number of streams into a larger number of modes helps improve mode separation through the DSP and is recommended when reliability is more important than throughput. Multiplexing the same number of streams into the same number of modes is a way to create orthogonal diversity paths and is typically used when higher data rates are a priority. In general, an OAM system architecture can be designed to allow one or more data signals to be multiplexed into one or more modes ranging from full spatial multiplexing to diversity transmission. For easier demodulation and lower design complexity at the receiver, the transmitter can signal how many data streams have been multiplexed to the receiver. In addition, the receiver can feed back demodulation quality information (e.g., through BER) so that the transmitter can adapt the multiplexing order. The receiver can also feed back a recommendation to the transmitter of how many multiplexed streams to transmit, since the receiver has the quality of all the OAM modes received.

[0108] Multiple stream transmission is typically achieved in wireless communications through a MIMO antenna configuration, where there are n antennas at the transmitter and n antennas at the receiver, and the n streams are sent simultaneously from the transmitter as separate and distinct data streams. In the channel, the streams interfere with each other, but are demultiplexed at the receiver using channel inversion and signal processing techniques.

[0109] There are two main differences between MIMO and OAM in millimeter wave implementations: Millimeter wave signals reflect poorly off structures, and therefore it is difficult to obtain a sufficient number of independent signal paths required to obtain a good MIMO channel. MIMO thrives in multipath-rich channels, while OAM thrives in multipath-poor line-of-sight (LoS) environments. In multipath-poor line-of-sight (LoS) environments, the OAM modes propagate along the same axis with minimal cross-mode interference.

[0110] Various beamforming and spatial multiplexing techniques can be used to maximize the channel capacity between the transmitter and the receiver. As can be seen from at least the above description, some physical channel conditions are well suited for OAM, while other conditions are better suited for beamforming or other propagation schemes to achieve higher aggregate channel capacity. Methods according to some aspects provide a flexible transmission scheme to maximize data throughput by switching between beamforming, MIMO, and OAM modes depending on the channel conditions to maximize system throughput. Receiver feedback can be used to estimate the channel and select an appropriate signaling scheme. Thus, methods and apparatus according to aspects use closed-loop signaling. Furthermore, the channel can vary randomly as a function of time, and thus the estimated channel information is used to adaptively determine whether beamforming or one of the multiple OAM transmission methods should be selected.

[0111] In millimeter wave systems such as WiGig, beamforming is used to direct directional high gain beams for communication between transmitters and receivers to largely offset the high path loss associated with millimeter wave transmission. Due to the larger available bandwidth at millimeter wave frequencies (e.g., WiGig has 7 GHz bandwidth within the 60 GHz transmission band), communication at these frequencies is desirable because high data throughput can be obtained over a wide frequency channel of transmission. In a user device, beamforming is achieved by connecting a given number of RF chains to a given number of closely spaced antenna elements. Phase adjustments across the antenna elements determine the direction of beamforming. In a beamforming system, the receiver feeds back channel quality metrics to the transmitter to best determine the best direction to direct the high gain beam.

[0112] Conventional beamforming can send only one single data stream along the path of the beam. The intelligent transmission scheme according to the aspect can opportunistically switch between a combination of beamforming and OAM modes to achieve maximum total channel capacity. Also, in a rich scattering environment, the system according to the aspect can switch between OAM, beamforming, and MIMO multiplexing / diversity modes depending on the channel quality and conditions.

[0113] In the following discussion, we assume that 1.) for a given distance between transmitter and receiver, OAM modes experience different path losses, 2.) higher OAM modes see higher path losses, 3.) OAM mode 0 is equivalent to conventional beamforming, and 4.) if the channel is LoS, OAM modes can be assumed to be orthogonal with no crosstalk, and if the channel is non-LoS, there is a high possibility of OAM mode cross interference. Thus, rich scattering channels can benefit from MIMO multiplexing or diversity.

[0114] Given the available OAM modes and knowing the channel conditions (e.g., LoS or non-LoS), a method according to an embodiment selects a subset of the available OAM modes (including beamforming) and allocates the available transmit power to the active OAM modes. In LoS channels, the OAM modes are orthogonal, so water-filling can optimally select the OAM mode and its corresponding allocated power.

[0115] FIG. 18 illustrates OAM node selection and power allocation with water-filling, according to some aspects. Four OAM modes are shown: OAM mode 0 (equivalent to traditional beamforming), mode 1, mode 2, and mode 3. The total power P is optimally allocated as shown, assuming OAM mode 3 is inactive (assuming noise on the channel indicates that OAM mode 3 should be inactive), such that OAM mode 0 is assigned P0 power, mode 1 is assigned P1 power, and mode 2 is assigned P2 power. In some aspects, the power can be split evenly between the selected modes, or all modes may be activated and the power split evenly between them. In some aspects, for example, only beamforming is performed and only OAM mode 0 is active. Path loss may increase with distance, and path loss may increase as the OAM mode increases.

[0116] The OAM modes can be realized using antenna arrays. The number of receive antenna elements determines the effective noise power after OAM / beamforming combining at the receiver. The number of antenna elements can be 1, 4, 8, and 12 for OAM modes 0, 1, 2, and 3, respectively. In general, the SNR of mode k after transmitter and receiver OAM / beamforming combining is:

number

[0117] When all OAM modes are kept active regardless of SNR, beamforming outperforms OAM in the low SNR range. OAM outperforms beamforming at shorter distances, and OAM performance converges to beamforming performance when smart mode selection and water-filling are applied. At longer distances, non-LoS conditions are more likely to occur, in which case the crosstalk orthogonality of OAM is lacking and OAM should not be selected.

[0118] 19A illustrates OAM mode selection based on signal-to-noise ratio (SNR) and distance between a transmitter and a receiver when one antenna element is used per OAM mode, in accordance with some aspects. FIG. 19B illustrates OAM mode selection based on signal-to-noise ratio (SNR) and distance between a transmitter and a receiver when a variable number of antenna elements are used per OAM mode, in accordance with some aspects. In both figures, it can be seen that the number of active OAM modes increases with SNR and decreases with increasing distance.

[0119] 20 illustrates a flowchart of a method 2000 for transmission mode switching according to some aspects. In an aspect, the method 2000 can be performed by a processing circuit (e.g., the baseband processor 110 (FIG. 1), the transmitter section 191A (FIG. 1A), the receiver section 191B (FIG. 1A), etc.).

[0120] Method 2000 may begin at operation 2002, where a processing circuit receives inputs including, among other inputs, total transmit power, channel conditions, and OAM mode path loss. The operations of method 2000 may be performed periodically, upon determining discarded data packets, sub-optimal channel conditions, etc.

[0121] Method 2000 may continue with operation 2004, where the processing circuitry determines whether the communication is LoS. This may be determined, for example, based on distance to the receiver, channel conditions, and detected path loss. However, aspects are not so limited. If the communication is LoS, then in operation 2006, the processing circuitry performs water-filling and selects the number of OAM modes. In operation 2008, the processing circuitry performs power allocation. Operation 2008 may proceed in a manner similar to that described above with reference to FIG. 18 and the accompanying text. The processing circuitry.

[0122] If the communication is not LoS, then another transmission mode is selected (e.g., MIMO or space-time code (STC) communication) in operation 2010. In either case, the results of method 2000 may include data 2012 stored in memory of the communication device regarding, for example, which and how many OAM modes were selected, the corresponding transmit power allocations, transmission modes, and other transmission related data.

[0123] Other Equipment 21 illustrates a block diagram of a communication device, such as an evolved Node-B (eNB), a next generation Node-B (gNB), an access point (AP), a wireless station (STA), a mobile station (MS), or a user equipment (UE), according to some aspects and performing one or more of the techniques disclosed herein. In alternative aspects, the communication device 2100 may operate as a standalone device or may be connected (e.g., networked) to other communication devices.

[0124] Circuitry (e.g., processing circuitry) is a collection of circuits implemented within the tangible entity of device 2100 that includes hardware (e.g., simple circuits, gates, logic, etc.). Circuitry membership may be flexible over time. Circuitry includes members that, when operational, may perform specified operations, either alone or in combination. In one example, the hardware of the circuitry may be invariably designed (e.g., hardwired) to perform a particular operation. In one example, the hardware of the circuitry may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) that include a machine-readable medium that is physically modified to encode instructions for a particular operation (e.g., a magnetically, electrically movable arrangement of invariant mass molecules, etc.).

[0125] In connecting the physical components, the underlying electrical properties of the hardware components are changed, for example, from insulator to conductor, or vice versa. The instructions enable the embedded hardware (e.g., execution unit or loading mechanism) to create members of the circuitry in the hardware through the variable connections to perform some of the specific operations when in operation. Thus, in one example, the machine-readable media element is part of the circuitry or is communicatively coupled to other components of the circuitry when the device is in operation. For example, any of the physical components may be used in multiple members of multiple circuitry. For example, during operation, an execution unit may be used for a first circuit of a first circuitry at one time and reused by a second circuit of the first circuitry or by a third circuit of the second circuitry at a different time. Further examples of these components for device 3200 are as follows:

[0126] In some aspects, the device 2100 can operate as a standalone device or can be connected (e.g., networked) to other devices. In a networked arrangement, the communication device 2100 can operate in the capacity of a server communication device, a client communication device, or both in a server-client network environment. In one example, the communication device 2100 can function as a peer communication device in a peer-to-peer (P2P) (or other distributed) network environment. The communication device 2100 can be a UE, eNB, PC, tablet PC, STB, PDA, cell phone, smartphone, web appliance, network router, switch or bridge, or any communication device capable of executing instructions that specify actions that the communication device should take. Furthermore, although only a single communication device is shown, the term "communication device" shall also be construed to include any collection of communication devices that individually or collectively execute a set (or sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), and other computer cluster configurations.

[0127] As described herein, examples may include or operate on logic or multiple components, modules, or mechanisms. A module is a tangible entity (e.g., hardware) that can perform a specified operation and may be configured or arranged in a particular manner. In an example, a circuit may be arranged in a specified manner (e.g., internally or relative to an external entity such as another circuit) as a module. In an example, one or more computer systems (e.g., stand-alone, client, or server computer systems) or one or more hardware processors may be configured in whole or in part with firmware or software (e.g., instructions, application portions, or applications) as modules that operate to perform specified operations. For example, the software may reside on a communication device readable medium. In an example, the software, when executed by the hardware underlying the module, causes the hardware to perform the specified operations.

[0128] Thus, the term "module" is understood to encompass a tangible entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transiently) configured (e.g., programmed) to operate in a specified manner or to perform some or all of any of the operations described herein. Considering examples where modules are temporarily configured, each of the modules need not be instantiated at any one time. For example, if the modules include a general-purpose hardware processor that is configured using software, the general-purpose hardware processor may be configured as different modules at different times. Thus, the software may configure the hardware processor, for example, to configure a particular module at one time and a different module at a different time.

[0129] A communications device (e.g., a UE) 2100 may include a hardware processor 2102 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 2104, a static memory 2106, and mass storage 2107 (e.g., a hard drive, tape drive, flash storage, or other block or storage device), some or all of which may communicate with each other via an interlink (e.g., a bus) 2108.

[0130] The communication device 2100 may further include a display device 2110, an alphanumeric input device 2112 (e.g., a keyboard), and a user interface (UI) navigation device 2114 (e.g., a mouse). In one example, the display device 2110, the input device 2112, and the UI navigation device 2114 may be touch screen displays. The communication device 2100 may further include a signal generating device 2118 (e.g., a speaker), a network interface device 2120, and one or more sensors 2121, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or another sensor. The communication device 2100 may include an output controller 2128, such as a serial (e.g., Universal Serial Bus (USB)), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection, to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.).

[0131] The storage device 2107 may include a communication device-readable medium 2122 on which one or more sets of data structures or instructions 2124 (e.g., software) are stored that embody or are utilized by any one or more of the techniques or functions described herein. In some aspects, the processor 2102, the main memory 2104, the static memory 2106, and / or the registers of the mass storage 2107 may be or include (completely or at least partially) the device-readable medium 2122 on which one or more sets of data structures or instructions 2124 that embody or are utilized by any one or more of the techniques or functions described herein are stored. In one example, one or any combination of the hardware processor 2102, the main memory 2104, the static memory 2104, or the mass storage 2116 may constitute the device-readable medium 2122.

[0132] As used herein, the term "device readable medium" is interchangeable with "computer readable medium" or "machine readable medium." Although the communication device readable medium 2122 is illustrated as a single medium, the term "communication device readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) configured to store one or more instructions 2124. The term "communication device readable medium" includes the term "machine readable medium" or "computer readable medium" and may include any medium that can store, encode, or carry instructions (e.g., instructions 2124) for execution by the communication device 2100 and cause the communication device 2100 to perform any one or more of the techniques of this disclosure, or any medium that can store, encode, or carry data structures used by or associated with such instructions. Non-limiting examples of communication device readable media may include solid-state memory, and optical and magnetic media. Particular examples of communication device readable media may include non-volatile memory such as semiconductor memory devices (e.g., Electrically Programmable Read Only Memory (EPROM)), Electrically Erasable Programmable Read Only Memory (EEPROM), and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; random access memory (RAM); and CD-ROM and DVD-ROM disks. In some examples, communication device readable media may include non-transitory communication device readable media. In some examples, communication device readable media may include communication device readable media that is not a transitory propagating signal.

[0133] The instructions 2124 may further be transmitted or received over the communications network 2126 using a transmission medium via the network interface device 2120 utilizing any one of a number of transport protocols. In one example, the network interface device 2120 may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas for connecting to the communications network 2126. In one example, the network interface device 2120 may include multiple antennas for wireless communication using at least one of single-input-multiple-output (SIMO), MIMO, or multiple-input-single-output (MISO) techniques. In some examples, the network interface device 2120 may wirelessly communicate using a Multiple User MIMO technique.

[0134] The term "transmission medium" shall be interpreted to include any intangible medium capable of storing, encoding, or carrying instructions for execution by communications device 2100, including digital or analog communications signals or other intangible media for facilitating the communication of such software. In this regard, transmission media in the context of this disclosure are device-readable media.

[0135] Implementation of the techniques described above may be accomplished by any number of specifications, configurations, or exemplary arrangements of hardware and software. It should be understood that functional units or capabilities described herein may be referred to or labeled as components or modules to more specifically emphasize their implementation independence. Such components may be embodied by any number of software or hardware forms. For example, a component or module may be implemented as a hardware circuit including custom very large scale integrated (VLSI) circuits or gate arrays, off-the-shelf semiconductors, e.g., logic chips, transistors, or other discrete components, and the like. A component or module may also be implemented in programmable hardware devices, such as field programmable gate arrays, programmable array logic, programmable logic devices, and the like. A component or module may also be implemented in software for execution by various types of processors. An identified component or module of executable code may include, for example, one or more physical or logical blocks of computer instructions, which may be organized, for example, as an object, procedure, or function. Nonetheless, the executable files of an identified component or module need not be physically located together, but may include different instructions stored in different locations that, when logically coupled together, constitute the component or module and achieve the stated purpose for the component or module.

[0136] Indeed, an executable code component or module may be a single instruction or many instructions, and may even be distributed across several different code segments, among different programs, and across several memory devices or processing systems. In particular, some aspects of the described process (such as rewriting the code and analyzing the code) may be performed on a processing system (e.g., on a computer in a data center) different from the processing system in which the code is located (e.g., on a computer embedded in a sensor or robot). Similarly, operational data may be identified and illustrated in components or modules herein, and may be embodied in any suitable form and organized in any suitable type of data structure. The operational data may be collected as a single data set or distributed across different locations, including across different storage devices, and may exist, at least in part, simply as electronic signals on a system or network. A component or module includes an agent operable to perform a desired function, and may be passive or active. For example, discussions herein utilizing terms such as "processing," "calculating," "calculating," "determining," "establishing," "analyzing," "checking," and the like may refer to operations and / or processes of a computer, computational platform, computing system, or other electronic computing device that manipulates and / or transforms data represented as physical (e.g., electronic) quantities in the computer's registers and / or memory into other data that is similarly represented as physical quantities in the computer's registers and / or memory, or other information storage medium that may store instructions for performing operations and / or processes.

[0137] The terms "plurality" and "multiple" as used herein include, for example, a "plurality" or "two or more." For example, "a plurality of items" includes two or more items.

[0138] References to "one embodiment," "one embodiment," "exemplary embodiment," "some embodiments," "demonstrative embodiments," "various embodiments," etc. indicate that the embodiments so described may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes that particular feature, structure, or characteristic. Additionally, repeated use of the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it may.

[0139] As used herein, unless otherwise specified, the use of ordinal adjectives "first," "second," "third," etc. to describe a common object merely indicates that different instances of similar objects are being referred to, and is not intended to indicate that the objects so described must be in a given sequence in time, space, ranking, or otherwise.

[0140] Some aspects may be used in connection with various devices and systems, such as a user equipment (UE), a mobile device (MD), a wireless station (STA), a personal computer (PC), a desktop computer, a mobile computer, a laptop computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a sensor device, an Internet of Things (IoT) device, a wearable device, a handheld device, a personal digital assistant (PDA) device, a handheld PDA device, an on-board device, an off-board device, a hybrid device, a vehicular device, a non-vehicular device, a mobile or portable device, a consumer device, a non-mobile or non-portable device, a wireless communication station, a wireless access point (AP), a wired or wireless router, a wired or wireless modem, a video device, an audio device, an audio video (A / V) device, a wired or wireless network, a wireless area network, a wireless video area network (Wireless Video Area Network, WVAN), a local area network (LAN), a wireless LAN (WLAN), a personal area network (PAN), a wireless PAN (WPAN), and the like.

[0141] Some aspects may incorporate, for example, devices and / or networks that operate in accordance with existing IEEE 802.11 standards (including IEEE 802.11-2016 (IEEE 802.11-2016, IEEE Standard for Information technology--Telecommunications and information exchange between systems Local and metropolitan area networks--Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, December 7, 2016)), IEEE E802.11ay (P802.11ay Standard for Information Technology--Telecommunications and Information Exchange Between Systems Local and Metropolitan Area Networks--Specific Requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications--Amendment: Enhanced Throughput for Operation in License-Exempt Bands Above 45 GHz)), and / or future versions and / or derivatives thereof, existing Wi-Fi Alliance (WiFi Alliance (WFA) Peer-to-Peer (P2P) Specification (WiFi P2P technical specification, version 1.5, including August 4, 2015) and / or future versions and / or derivatives thereof, devices and / or networks that operate in accordance with existing Wireless-Gigabit-Alliance (WGA) specifications (including the Wireless Gigabit Alliance, Inc WiGig MAC and PHY Specification Version 1.1, April 2011, Final specification) and / or future versions and / or derivatives thereof, devices and / or networks that operate in accordance with existing cellular specifications and / or protocols, such as 3rd Generation Partnership Project (3GPP), 3GPP Long Term Evolution (LTE), and / or future versions and / or derivatives thereof, units and / or devices that are part of the above networks, etc.

[0142] Some aspects may be used in connection with one-way and / or two-way wireless communication systems, cellular radiotelephone communication systems, mobile phones, cellular telephones, radiotelephones, personal communication system (PCS) devices, PDA devices incorporating wireless communication devices, mobile or portable Global Positioning System (GPS) devices, devices incorporating GPS receivers or transceivers or chips, devices incorporating RFID elements or chips, multiple-input multiple-output (MIMO) transceivers or devices, single-input multiple-output (SIMO) transceivers or devices, multiple-input single-output (MISO) transceivers or devices, devices having one or more internal antennas and / or external antennas, Digital Video Broadcast (DVB) devices or systems, multi-standard wireless devices or systems, wired or wireless handheld devices such as smartphones, Wireless Application Protocol (WAP) devices, and the like.

[0143] Some aspects relate to one or more types of wireless communication signals and / or systems, such as radio frequency (RF), infrared (IR), Frequency-Division Multiplexing (FDM), Orthogonal FDM (OFDM), Orthogonal Frequency-Division Multiple Access (OFDMA), Spatial Divisional Multiple Access (SDMA), FDM Time-Division Multiplexing (TDM), Time-Division Multiple Access (TDMA), Multi-User MIMO (MU-MIMO), Extended TDMA (E-TDMA), General Packet Radio Service (GPRS), extended GPRS, Code-Division Multiple Access (CDMA), Code Division ... Access, CDMA), Wideband CDMA (WCDMA), CDMA2000, Single-Carrier CDMA, Multi-Carrier CDMA, Multi-Carrier Modulation (MDM), Discrete Multi-Tone (DMT), Bluetooth (registered trademark), Global Positioning System (GPS), Wi-Fi, Wi-Max (registered trademark), ZigBee (registered trademark) TM, Ultra-Wideband (UWB), Global System for Mobile communication (GSM), 2G, 2.5G, 3G, 3.5G, 4G, fifth generation (5G) mobile networks, 3GPP, Long Term Evolution (LTE), LTE Advanced, Enhanced Data rates for GSM Evolution (EDGE), etc. Other aspects may be used in various other devices, systems, and / or networks associated with, for example, millimeter wave and sub-millimeter wave (sub-mmWave) based communications.

[0144] The term "wireless device" as used herein includes, for example, a device capable of wireless communication, a communication device capable of wireless communication, a communication station capable of wireless communication, a portable or non-portable device capable of wireless communication, etc. In some exemplary aspects, a wireless device may be or include a peripheral device integrated with or attached to a computer. In some exemplary aspects, the term "wireless device" may optionally include wireless services.

[0145] The term "communicate," as used herein with respect to a communication signal, includes transmitting a communication signal and / or receiving a communication signal. For example, a communication unit that can communicate a communication signal may include a transmitter for transmitting the communication signal to at least one other communication unit and / or a communication receiver for receiving the communication signal from at least one other communication unit. The verb communicate may be used to refer to the action of transmitting and / or receiving. In one example, the phrase "communicate a signal" may refer to the action of transmitting a signal by a first device and may not necessarily include the action of receiving a signal by a second device. In another example, the phrase "communicate a signal" may refer to the action of receiving a signal by a first device and may not necessarily include the action of transmitting a signal by a second device.

[0146] Some example aspects may be used in connection with a WLAN, e.g., a WiFi network. Other aspects may be used in connection with any other suitable wireless communication network, e.g., a wireless area network, a "piconet," a WPAN, a WVAN, etc.

[0147] Some example embodiments may be used in connection with wireless communication networks communicating over a frequency band above 45 gigahertz (GHz), e.g., above 60 GHz, or within the terahertz frequency band (e.g., between 300 GHz and 10 THz). However, other embodiments may be implemented utilizing any other suitable wireless communication frequency band, e.g., a frequency band in the Extremely High Frequency (EHF) band (millimeter wave (mmWave) frequency band), e.g., a frequency band between 20 GHz and 300 GHz, a frequency band above 45 GHz, a frequency band below 20 GHz, e.g., the sub-1 GHz (S1G) band, the 2.4 GHz band, the 5 GHz band, a WLAN frequency band, a WPAN frequency band, a frequency band according to the WGA specification, etc.

[0148] As used herein, the term "circuitry" may refer to, be a part of, or include, e.g., an application specific integrated circuit (ASIC), an integrated circuit, an electronic circuit, a processor (shared, dedicated, or group), and / or memory (shared, dedicated, or group), combinatorial logic circuitry, and / or other suitable hardware components that provide the described functionality. In some aspects, the circuitry may include logic that is at least partially operable in hardware. In some aspects, the circuitry may be implemented as part of and / or in the form of a radio virtual machine (RVM), e.g., as part of a radio processor (RP) configured to execute code to configure one or more operations and / or functionality of one or more radio components.

[0149] The term "logic" may refer to, for example, computational logic embedded in the circuitry of a computing device and / or computational logic stored in memory of a computing device. For example, logic may be accessible by a processor of a computing device to execute the computational logic to perform computational functions and / or operations. In one example, logic may be embedded in various types of memory and / or firmware, e.g., various chips and / or silicon blocks of a processor. Logic may be included in and / or implemented as part of various circuits, e.g., radio circuits, receiver circuits, control circuits, transmitter circuits, transceiver circuits, processor circuits, etc. In one example, logic may be embedded in volatile and / or non-volatile memory, including random access memory, read-only memory, programmable memory, magnetic memory, flash memory, persistent memory, etc. Logic may be executed by one or more processors, using memory coupled to one or more processors, e.g., registers, buffers, stacks, etc., as needed to execute the logic.

[0150] The term "antenna" as used herein may include any suitable configuration, structure, and / or arrangement of one or more antenna elements, components, units, assemblies, and / or arrays. In some aspects, an antenna may achieve transmit and receive functions using separate transmit and receive antenna elements. In some aspects, an antenna may achieve transmit and receive functions using common and / or integrated transmit / receive elements. An antenna may include, for example, a phased array antenna, a single element antenna, a set of switched beam antennas, etc.

[0151] The phrase "peer-to-peer (PTP) communications" as used herein may refer to device-to-device communications over a wireless link between devices ("peer-to-peer link"). PTP communications may include, for example, WiFi Direct (WFD) communications, e.g., WFD peer-to-peer (P2P) communications, wireless communications over a direct link in a quality of service (QoS) basic service set (BSS), tunneled direct-link setup (TDLS) links, STA-to-STA communications in an independent basic service set (IBSS), and the like.

[0152] Some example aspects are described herein with respect to WiFi communications, however, other aspects may be implemented with respect to any other communications schemes, networks, standards, and / or protocols.

[0153] In some exemplary aspects, the wireless communication device may implement a millimeter wave (mmWave) or sub-millimeter wave radio front-end module (RFEM), such as those described above.

[0154] Millimeter wave may be defined as the frequency range extending from about 30 GHz to about 300 GHz, and in fact currently covers several individual licensed and unlicensed frequency bands. Sub-millimeter wave may be defined as the frequency range extending to the terahertz band (0.3 THz to 10 THz). Similar to millimeter wave communication, sub-millimeter wave communication in the terahertz band can be used as mobile backhaul to transfer large bandwidth signals between base stations and chip-to-chip communication.

[0155] Currently available unlicensed mmWave frequency bands are around 60 GHz. Licensed frequency bands may include 28 GHz, 39 GHz, 73 GHz, and 120 GHz. The availability of these bands and the specific frequency ranges of each vary by regulatory jurisdiction, and in some cases (especially for licensed band operation), significant regulatory uncertainty still exists in some countries. Communications testing using sub-submillimeter communications in the terahertz band is ongoing. Challenges associated with mmWave and submillimeter based communications include increased power consumption, limited range, signal loss due to the use of regular cables instead of traces, and challenges due to the integration of multiple antennas for beamforming. Some of these challenges (e.g., related to increased power consumption of submillimeter communication systems operating in the terahertz band) are addressed in the present disclosure as previously discussed herein by several aspects.

[0156] Additional Notes and Examples Further examples of embodiments of the methods, systems, and devices described herein include the following non-limiting configurations, each of which may stand alone or may be combined in any permutation or combination with any one or more of the other examples provided above or throughout this disclosure.

[0157] Although the embodiments have been described with reference to certain exemplary embodiments, it will be apparent that various modifications and changes can be made to these embodiments without departing from the broader spirit and scope of the present disclosure. Accordingly, the specification and drawings should be construed in an illustrative and not a restrictive sense. The accompanying drawings, which form a part of this specification, show, by way of example and not of limitation, specific embodiments in which the subject matter may be practiced. The illustrated embodiments are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of the present disclosure. Accordingly, this detailed description should not be construed in a limiting sense, and the scope of the various embodiments is defined solely by the appended claims, along with the full scope of equivalents to which such claims are entitled.

[0158] Aspects of the inventive subject matter may be referred to herein individually and / or collectively by the term "aspects" merely for convenience and without any intention of intentionally limiting the scope of the present application to a single aspect or inventive concept when multiple aspects or inventive concepts are in fact disclosed. Thus, although specific aspects have been illustrated and described herein, it should be understood that any arrangement calculated to achieve the same purpose may be substituted for the specific aspect shown. The present disclosure is intended to cover any and all adaptations or variations of the various aspects. Combinations of the above aspects, as well as other aspects not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

[0159] In this document, the terms "a" or "an" are used to include one or more than one, as is common in patent documents, independent of any other instance or usage of "at least one" or "one or more." In this document, the term "or" is used to refer to a non-exclusive or, whereby "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In this document, the terms "including" and "in which" are used as the plain English equivalents of the terms "comprising" and "wherein," respectively. Also, in the following claims, the terms "including" and "comprising" are open-ended, i.e., a system, UE, article, composition, formula, or process that includes elements in addition to those recited after such terms in a claim is still deemed to be within the scope of that claim. Moreover, in the following claims, the terms "first," "second," "third," etc. are used merely as labels and are not intended to impose numerical requirements on their objects.

[0160] The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. The Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Moreover, in the foregoing Detailed Description, it will be seen that various features have been grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Accordingly, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment.

[0161] Described below are various examples of the methods, machine-readable media, and systems (eg, machines, devices, or other apparatus) discussed herein.

[0162] Example 1 is an apparatus for a communications device, the apparatus including an antenna array; and a processing circuit coupled to the antenna array and configured to initialize a beam tracking algorithm based on received signals received at the antenna array, where the antenna phases used for beam tracking are based on a predetermined set of constraints including an upper phase limit and a lower phase limit to generate a beam tracking result, generate a calibration vector based on the beam tracking result, and receive subsequent transmissions using a codebook adapted based on the calibration vector.

[0163] In Example 2, the subject matter of Example 1 includes the processing circuitry further configured to calculate a phase difference between a best beam direction and the beam tracking result, and the calibration vector is based on the phase difference.

[0164] In Example 3, the subject matter of any one of Examples 1-2 includes where at least one of the upper phase limit and the lower phase limit is set based on a maximum phase error that may be generated due to thermal heating.

[0165] In Example 4, the subject matter of any one of Examples 1-3 includes where at least one of the upper phase limit and the lower phase limit is set based on a maximum divergence of antenna elements of the antenna array.

[0166] In Example 5, the subject matter recited in any one of Examples 1-4 includes the received signal not including a pilot signal.

[0167] In Example 6, the subject matter of any one of Examples 1-5 includes the beam tracking algorithm being based on antenna weights that maximize an output power of a signal output by the processing circuitry.

[0168] In Example 7, the subject matter of Example 6 includes wherein the beam tracking algorithm includes an equal gain combining technique.

[0169] In Example 8, the subject matter recited in any one of Examples 1-7 includes where the apparatus is included in a fully digital receiver.

[0170] Example 9 is an apparatus for a communications device, the apparatus including an antenna array; and a baseband circuit coupled to the antenna array and configured to perform a transmit sector sweep to determine a best transmit direction, perform a receive sector sweep based on the best transmit direction, measure a signal-to-noise ratio at a receiver using the best transmit direction and a best receiver direction, and calculate a power allocation for a subsequent transmission based on the signal-to-noise ratio.

[0171] In Example 10, the subject matter of Example 10 includes the baseband circuitry further configured to generate a reduced channel matrix based on a geometry of a transmit antenna array and a receive antenna array of a communication device.

[0172] In Example 11, the subject matter of Example 10 includes the baseband circuitry further configured to generate an approximation of a full channel matrix based on the reduced channel matrix.

[0173] In Example 12, the subject matter of Example 10 includes the baseband circuitry further configured to multiplex a plurality of data streams based on the reduced channel matrix.

[0174] In Example 13, the subject matter of Example 12 includes a precoder for the multiplexing being a channel eigenvector extracted from the reduced channel matrix.

[0175] In Example 14, the subject matter of example 10 includes the reduced channel matrix further being based on a selected distance between the transmit antenna array and the receive antenna array.

[0176] In Example 15, the subject matter of Example 14 includes the baseband circuitry further configured to estimate the distance based on the signal-to-noise ratio.

[0177] In Example 16, the subject matter of any one of Examples 9-15 includes where calculating the power allocation includes performing a water-filling algorithm.

[0178] In Example 17, the subject matter of example 16 includes the water-filling is applied across multiplexed streams having an adaptive number of streams.

[0179] In Example 18, the subject matter of example 17 includes the adaptive number of streams based on the signal-to-noise ratio.

[0180] In Example 19, the subject matter of any one of Examples 9-18 includes power being allocated equally to active streams.

[0181] In Example 20, the subject matter of example 19 includes determining the number of active streams based on the signal-to-noise ratio.

[0182] In Example 21, the subject matter of any one of Examples 9-20 includes the baseband circuitry further configured to perform multiple stream MIMO detection after receive sector sweeping.

[0183] Example 22 is an apparatus for a communications device, the apparatus including: an array of antenna elements, the array being arranged to generate at least one Orbital Angular Momentum (OAM) mode; and a processing circuit coupled to the antenna array and configured to detect whether a communication to a neighboring device is line of sight (LoS) based on at least one of a detected path loss and a channel condition, and to select a number of OAM modes for a subsequent transmission in response to detecting that the communication is LoS.

[0184] In Example 23, the subject matter of Example 22 includes the processing circuitry further configured to allocate power among the selected number of OAM modes.

[0185] In Example 24, the subject matter of example 23 includes the allocation following a water-filling algorithm.

Claims

1. An apparatus for a communication device, comprising: An antenna array; coupled to the antenna array; Executing a beam tracking algorithm based on the received signals received by the antenna array, in which the antenna phases used for beam tracking are limited by an upper phase limit and a lower phase limit, to generate a beam tracking result; generating a calibration vector based on the beam tracking results; receiving a subsequent transmission using a codebook adjusted based on the calibration vector; A processing circuit configured as above; Including, the processing circuitry is further configured to calculate a phase difference between a best beam direction in which received power is maximized and the beam tracking result, and the calibration vector is based on the phase difference. Device.

2. The apparatus of claim 1 , wherein at least one of the upper phase limit and the lower phase limit is set based on a maximum phase error that can be produced due to thermal heating.

3. The apparatus of claim 1 , wherein at least one of the upper phase limit and the lower phase limit is set based on a maximum divergence angle of an antenna element of the antenna array.

4. The apparatus of claim 1 , wherein the received signal does not include a pilot signal.

5. The apparatus of claim 1 , wherein the beam tracking algorithm is based on antenna weights that maximize an output power of a signal output by the processing circuitry.

6. The apparatus of claim 5 , wherein the beam tracking algorithm includes an equal gain combining technique.

7. The apparatus of claim 1 , wherein the apparatus is included in a fully digital receiver.

8. coupled to the antenna array; Perform a transmit sector sweep to determine the best transmit direction; performing a receive sector sweep based on the best transmission direction; measuring a signal to noise ratio at a receiver using the best transmit direction and best receiver direction; Calculating a power allocation for a subsequent transmission based on the signal-to-noise ratio. A baseband circuit configured as above. The apparatus of claim 1 , comprising:

9. The baseband circuit further comprises:

10. The apparatus of claim 8, configured to generate a reduced channel matrix based on a geometry of a transmit antenna array and a receive antenna array of a communication device.

10. The baseband circuit further comprises: The apparatus of claim 9 , configured to generate an approximation of a full channel matrix based on the reduced channel matrix.

11. The baseband circuit further comprises: The apparatus of claim 9 , configured to multiplex multiple data streams based on the reduced channel matrix.

12. The apparatus of claim 11 , wherein the precoder for the multiplexing is a channel eigenvector extracted from the reduced channel matrix.

13. 10. The apparatus of claim 9, wherein the reduced channel matrix is ​​further based on a selected distance between the transmit antenna array and the receive antenna array.

14. The apparatus of claim 13 , wherein the baseband circuitry is further configured to estimate the distance based on the signal-to-noise ratio.

15. The apparatus of claim 8 , wherein calculating the power allocation comprises performing a water-filling algorithm.

16. The apparatus of claim 15, wherein the water-filling algorithm is applied across multiplexed streams having an adaptive number of streams.

17. The apparatus of claim 16 , wherein the adaptive number of streams is based on the signal-to-noise ratio.

18. The apparatus of claim 8 , wherein power is allocated to active streams determined based on the signal-to-noise ratio.

19. The apparatus of claim 18 , wherein the number of active streams is determined based on the signal-to-noise ratio.

20. The baseband circuit further comprises: The apparatus of claim 8 , configured to perform multiple stream MIMO detection after receive sector sweeping.

21. the antenna array includes an array of antenna elements, the array being arranged to generate at least one orbital angular momentum (OAM) mode; The processing circuitry includes: Detecting whether communication to a neighboring device is line of sight (LoS) based on at least one of the detected path loss and channel conditions; In response to detecting that the communication is LoS, select an OAM mode number for a subsequent transmission. It is configured as follows:

2. The apparatus of claim 1.

22. 22. The apparatus of claim 21, wherein the processing circuitry is further configured to allocate power among the selected number of OAM modes.

23. The apparatus of claim 22 , wherein the allocation follows a water-filling algorithm.

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