Pre-distortion training feedback via inductive coupling

Abstract

Certain aspects of the present disclosure provide techniques for pre-distortion training feedback via inductive coupling. An example apparatus includes a receive path, a transmit path including an amplifier having a first output inductively coupled to the receive path, a memory, and a processor coupled to the memory. The processor is configured to cause the apparatus to obtain a first signal via inductive coupling of the receive path to the first output of the amplifier based on a second signal output by the amplifier, determine a parameter of a pre-distortion associated with the amplifier based at least in part on the first signal, pre-distort a third signal based at least in part on the parameter, amplify the pre-distorted third signal via the amplifier, and transmit the amplified third signal.

Description

Cross-references to related applications

[0001] This patent application claims the benefit and priority of U.S. Provisional Application No. 63 / 627,022, filed January 30, 2024, and U.S. Non-Provisional Patent Application No. 18 / 883,156, filed September 12, 2024, the entire contents of which are hereby expressly incorporated by reference. Technical Field

[0002] This disclosure relates to various aspects of wireless communication, and more particularly to predistortion training. Background Technology

[0003] Wireless communication systems are widely deployed to provide a variety of telecommunications services, such as telephone, video, data, messaging, and broadcasting. These wireless communication systems may employ multiple access technologies that enable communication with multiple users by sharing available wireless communication system resources. Wireless communication devices may transmit RF signals via any of a variety of suitable radio access technologies (RATs) (including but not limited to 5G New Radio (NR), Evolved Universal Terrestrial Radio Access (E-UTRA), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Wideband CDMA (WCDMA), Global System for Mobile Communications (GSM), Bluetooth, Bluetooth Low Energy (BLE), ZigBee, Wireless Local Area Network (WLAN) RATs (e.g., the IEEE 802.11 specification), and any future RATs).

[0004] In some cases, wireless communication devices are equipped with an RF transceiver (also known as an RF front-end) for transmitting received radio frequency (RF) signals. Typically, modulation techniques such as phase shift keying (PSK) or any other suitable modulation technique are used to modulate the baseband signal to transmit information. In transmit mode, the RF transceiver is responsible for multiplexing the baseband signal with the RF carrier signal transmitted over the air (e.g., a wireless communication channel). This operation is called up-conversion. In receive mode, the RF transceiver converts the received RF signal back into a baseband signal. This operation is called down-conversion. The received baseband signal can then be demodulated into the information encoded at the transmitter. An RF transceiver may consist of cascaded components in the transmit and receive chains, respectively. The cascaded components may include one or more of, for example, attenuators, switches, couplers, filters, mixers, amplifiers, frequency synthesizers, oscillators, antenna tuners, duplexers, combiners, detectors, etc.

[0005] Despite significant technological advancements in RF circuits over the years, challenges remain. For example, some RF circuits, such as amplifiers, exhibit nonlinear characteristics. Therefore, there has been a long-standing desire to improve the technical performance of RF circuits, such as amplifiers, through predistortion. Summary of the Invention

[0006] Some aspects provide an apparatus configured for wireless communication. The apparatus includes a receive path comprising a variable resistive element. The apparatus also includes a transmit path comprising a first amplifier having a first output inductively coupled to the receive path. The apparatus further includes one or more memories. The apparatus includes one or more processors coupled to the one or more memories, the receive path, and the transmit path. The one or more processors are configured to cause the apparatus to: obtain a first signal based on a second signal output from the first amplifier, inductively coupled to the first output of the first amplifier via the receive path, wherein the variable resistive element is configured to adjust the attenuation applied to the first signal via a variable resistance adjustment of the variable resistive element; determine one or more parameters of digital predistortion (DPD) associated with the first amplifier, at least in part based on the first signal; predistort a third signal, at least in part based on the one or more parameters; amplify the predistorted third signal via the first amplifier; and transmit the amplified third signal.

[0007] Some aspects provide a method for wireless communication by a device. The method includes: obtaining a first signal based on a second signal output from a first amplifier via a receiving path inductively coupled to the output of the first amplifier, the receiving path including a variable resistor element configured to adjust the attenuation applied to the first signal via a variable resistance of the variable resistor element. The method further includes: determining one or more parameters of digital predistortion (DPD) associated with the first amplifier, at least in part based on the first signal. The method further includes: predistorting a third signal, at least in part based on one or more parameters. The method further includes: amplifying the predistorted third signal via the first amplifier. The method further includes: transmitting the amplified third signal.

[0008] Some aspects provide an apparatus configured for wireless communication. The apparatus includes a receive path and a transmit path, the transmit path including a first amplifier having a first output inductively coupled to the receive path. The apparatus also includes one or more memories and one or more processors coupled to the one or more memories, the receive path, and the transmit path. The one or more processors are configured to cause the apparatus to: obtain a first signal based on a second signal output from the first amplifier, via the receive path inductively coupled to the first output of the first amplifier; determine one or more parameters of digital predistortion (DPD) associated with the first amplifier, at least in part based on the first signal; predistort a third signal, at least in part based on the one or more parameters; amplify the predistorted third signal via the first amplifier; and transmit the amplified third signal.

[0009] Some aspects provide an apparatus configured for wireless communication. The apparatus includes a receive path comprising a variable resistive element. The apparatus also includes one or more memories and one or more processors coupled to the one or more memories and the receive path. The one or more processors are configured to cause the apparatus to: determine one or more parameters for distortion compensation based on a first signal received inducted at the receive path during a first mode; and adjust a first attenuation applied to the first signal received by the inductor via a variable resistance of the variable resistive element based on the first mode.

[0010] Some aspects provide a method for wireless communication by a device. The method includes: obtaining a first signal based on a second signal output from a first amplifier via a transmit path, inductively coupled to the output of the first amplifier via a receive path. The method further includes: determining one or more parameters of digital predistortion (DPD) associated with the first amplifier, at least in part based on the first signal. The method further includes: predistorting a third signal, at least in part based on the one or more parameters. The method further includes: amplifying the predistorted third signal via the first amplifier. The method further includes: transmitting the amplified third signal.

[0011] Other aspects provide: an apparatus operable to, configured to, or otherwise adapted to perform one or more of the foregoing methods and / or those methods described elsewhere herein; a non-transitory computer-readable medium comprising instructions which, when executed by a processor of the apparatus, cause the apparatus to perform the foregoing methods and those methods described elsewhere herein; a computer program product embodied on a computer-readable storage medium comprising: code for performing the foregoing methods and those methods described elsewhere herein; and / or an apparatus comprising components for performing the foregoing methods and those methods described elsewhere herein. By way of example, an apparatus may include a processing system, a device having a processing system, or a processing system cooperating via one or more networks.

[0012] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and specifically pointed out in the claims. The following description and drawings illustrate certain exemplary features of these one or more aspects in detail. However, these features indicate only a few of the various ways in which the principles of the various aspects may be employed. Attached Figure Description

[0013] To gain a more detailed understanding of the foregoing features of this disclosure, a more specific description of the brief overview can be obtained by referring to some aspects illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered as limiting its scope, as other equally valid aspects may be acknowledged in this description.

[0014] Figure 1 An example wireless communication system is shown.

[0015] Figure 2 An example wireless communication device is shown that communicates with another device.

[0016] Figure 3A and Figure 3B An example transceiver architecture is illustrated, which employs inductive coupling between the receive and transmit paths for predistortion training.

[0017] Figure 4 An example architecture for training and applying predistortion in a transceiver is illustrated.

[0018] Figure 5 Example resistor sets that can be used in the receive path of a transceiver are shown.

[0019] Figure 6 An example operation of wireless communication by the device is illustrated.

[0020] Figure 7 Examples are illustrated of communication devices that may include various components configured to perform the operations of the techniques disclosed herein.

[0021] For ease of understanding, the same reference numerals have been used where possible to denote common elements in the figures. It is conceivable that elements disclosed in one aspect may be usefully applied to other aspects without specific description. Detailed Implementation

[0022] Various aspects of this disclosure provide apparatus, methods, processing systems, and computer-readable media for predistortion training feedback via inductive coupling.

[0023] In a radio frequency (RF) transmitter, the power amplifier (PA) converts a low-power signal into a high-power signal for transmission via the antenna. Typically, the PA consumes a significant amount of current to perform this high-power conversion within the transceiver. Nonlinearity in the PA can lead to gain compression, intermodulation distortion, amplitude-to-phase modulation (AM-PM) conversion, amplitude-to-amplitude modulation (AM-AM) conversion, spectral regrowth, and more. These nonlinear effects can cause adjacent channel interference, in-band distortion, block error rate degradation, and / or non-compliance with certain regulations regarding RF transmission (e.g., permitted out-of-band RF transmission).

[0024] Predistortion is a technique used to compensate for nonlinear effects in amplifiers, such as power amplifiers (PAs). Predistortion (e.g., phase and / or amplitude correction) can be applied to the input signal of a PA to eliminate or compensate for nonlinear effects and improve the linearity of the PA's output. Linearizing the PA output via predistortion can achieve efficiency in terms of power consumption and / or reduced chip heat. Digital predistortion (DPD) is the process of applying predistortion in the digital domain, such as predistorting digital baseband signals. DPD provides a cost-effective method for applying predistortion to communication signals. Therefore, predistortion can achieve certain power efficiencies by allowing the PA to operate in the nonlinear region of its gain response (e.g., at gain compression or saturation). The nonlinear region can refer to the time during which the PA operates at the level of nonlinear amplification of the signal.

[0025] Technical challenges of predistortion include, for example, capturing appropriate feedback to characterize the nonlinearity of the PA used for predistortion training. During predistortion training (e.g., during device calibration and / or online training phases), the nonlinear effect of the PA is characterized by feeding the training signal as input to the PA and comparing the corresponding output signal of the PA with the training signal. The nonlinearity of the PA may introduce certain gain and / or phase errors into the training signal, as indicated in the output signal. Predistortion aims to compensate for the nonlinear effect of the PA by changing the input signal fed to the PA, so that the nonlinear distortion of the PA is effectively eliminated from the output signal of the PA.

[0026] Due to the ongoing desire to reduce the size of RF transceiver components (e.g., to save cost and power), obtaining the PA output signal for predistortion training without additional distortion and / or interference from the input training signal can present certain challenges. Some predistortion training feedback architectures selectively couple the transceiver's receive path to the PA output on the transceiver's transmit path via signal traces to provide a predistortion feedback path that can feed the PA output to a digital signal processor (DSP). For example, the predistortion feedback path may include switches, attenuation capacitors, transimpedance amplifiers, separate feedback mixers, and / or separate baseband amplifiers / filters coupled to the signal trace between the PA outputs on the receive and transmit paths. Therefore, in some cases, such as because the receive and transmit paths share the same power and ground, or due to isolation specifications between components, the training signal may constructively or destructively interfere with the PA feedback signal. Additionally, the feedback mixer and / or transimpedance amplifier can impact the power consumption and space requirements of the circuitry used for predistortion training. The transimpedance amplifier may also have nonlinear effects on the feedback signal, which can affect the signal quality of the feedback signal when characterizing the nonlinearity of the PA. Attenuation capacitors allow noise or interference to pass through the common ground between the transmit and receive paths, which can affect the signal quality of the feedback signal.

[0027] The aspects described herein can overcome the aforementioned technical problems, for example, by providing predistortion training feedback via inductive coupling. To characterize the nonlinear effects of the amplifier used for predistortion training, the amplifier's output can be inductively coupled to the transceiver's receive path. For example, the transceiver's transmit path may include a first inductive element coupled to the amplifier's output, and the transceiver's receive path may include a second inductive element arranged inductively coupled to the first inductive element. In some aspects, the first inductive element may include a transformer, which can also be used to provide impedance matching between the transmit path and the antenna. In some aspects, a resistor bank may be coupled to the second inductive element to selectively attenuate the signal obtained via inductive coupling between the amplifier's output and the receive path. The resistor bank can apply attenuation to reduce the nonlinear effects of the receive path on the PA feedback signal.

[0028] The techniques described herein for predistortion training via inductive coupling offer various beneficial technical effects and / or advantages. Inductive coupling for predistortion training, as described herein, enables reduced power consumption and / or reduced circuit space in the predistortion training circuit. For example, because the predistortion feedback path is implemented via inductive coupling, it eliminates certain nonlinear active circuits, such as the transimpedance amplifiers discussed above, which would otherwise affect power consumption, space, and / or auxiliary nonlinear effects for predistortion training. Inductive coupling for predistortion training, as described herein, eliminates attenuating capacitors in the predistortion feedback path, and therefore, inductive coupling suppresses or avoids certain interference or noise allowed through the common ground node. Inductive coupling for predistortion training, as described herein, enables effective isolation from interference and / or noise between the transmit and receive paths during predistortion training, and consequently, improved signal quality for the feedback signal used to characterize PA nonlinearity. Improved signal quality via the inductively coupled feedback signal described herein can enable improved predistortion (e.g., elimination of PA nonlinearity) and PA performance, such as reduced error vector magnitude (EVM) and / or improved PA efficiency (e.g., operating temperature, power consumption, and / or gain compression).

[0029] Figure 1Example wireless communication system 100 is illustrated, in which aspects of this disclosure may be performed. For example, wireless communication system 100 may include a wireless wide area network (WWAN), a wireless local area network (WLAN), and / or a satellite network. For example, a WWAN may include a new radio (NR) system (e.g., a fifth-generation (5G) NR network), an evolved universal terrestrial radio access (E-UTRA) system (e.g., a fourth-generation (4G) network), a universal mobile telecommunications system (UMTS) (e.g., a second-generation (2G) or third-generation (3G) network), a code division multiple access (CDMA) system (e.g., a 2G / 3G network), any future WWAN system, or any combination thereof. A WLAN may include a wireless network configured to communicate according to Institute of Electrical and Electronics Engineers (IEEE) standards (such as one or more standards in the 802.11 standard). In some cases, wireless communication system 100 may include a device-to-device (D2D) communication network or a short-range communication system, such as Bluetooth or near-field communication (NFC).

[0030] like Figure 1 As illustrated, the wireless communication system 100 may include a first wireless device 102 that communicates with any of the various second wireless devices 104a-d (hereinafter referred to as "second wireless devices 104") via any of the various radio access technologies (RATs), wherein a wireless device may refer to a wireless communication device. RATs may include, for example, WWAN communication (e.g., E-UTRA and / or 5G NR), WLAN communication (e.g., IEEE 802.11), vehicle-to-everything (V2X) communication, non-terrestrial network (NTN) communication, short-range communication (e.g., Bluetooth), etc.

[0031] The first wireless device 102 may include any wireless communication device from a variety of wireless communication devices, including user equipment (UE), base station, radio station, access point, customer premises equipment (CPE), etc. In some aspects, the first wireless device 102 includes a predistortion manager 106 that controls predistortion training or calibration via inductive coupling according to various aspects of this disclosure.

[0032] The second wireless device 104 may include, for example, a base station 104a, a vehicle 104b, an access point (AP) 104c, and / or a user equipment (UE) 104d. Furthermore, the wireless communication system 100 may include terrestrial aspects (such as terrestrial network entities (e.g., base station 104a and / or access point 104c)) and / or non-terrestrial aspects (such as airborne platforms and / or airborne platforms), which may include onboard network entities (e.g., one or more base stations) capable of communicating with other network elements (e.g., terrestrial base stations) and / or user equipment.

[0033] Base station 104a may typically include: NodeB, enhanced NodeB (eNB), next-generation enhanced NodeB (ng-eNB), next-generation NodeB (gNB or gNodeB), access point, transceiver base station, radio base station, radio transceiver, transceiver function, transmit / receive point, etc. Base station 104a can provide communication coverage for a corresponding geographic coverage area, which may sometimes be referred to as a cell, and in some cases may overlap (e.g., a small cell may have a coverage area that overlaps with the coverage area of ​​a macro cell). For example, the base station can provide communication coverage for macro cells (covering a relatively large geographic area), pico cells (covering a relatively small geographic area, such as a stadium), femtocells (covering a relatively small geographic area (e.g., a home)) and / or other types of cells.

[0034] The first wireless device 102 and / or UE 104d may generally include: cellular phones, smartphones, Session Initiation Protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players, cameras, game consoles, tablet computers, smart devices, wearable devices, vehicles, electricity meters, air pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, Internet of Things (IoT) devices, always-on (AON) devices, edge processing devices, or other similar devices. The UE may also be more generally referred to as a mobile device, wireless device, wireless communication device, radio station (STA), mobile station, subscriber station, mobile subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, remote device, access terminal, mobile terminal, wireless terminal, remote terminal, mobile phone, and other terms.

[0035] Figure 2 An example component of a first wireless device 102 is illustrated, which can be used to communicate with any second wireless device in the second wireless device 104.

[0036] The first wireless device 102 may be or may include a chip, system-on-a-chip (SoC), system-in-package (SiP), chipset, package, or device that includes one or more modems 210 (hereinafter referred to as "modem 210"). In some cases, modem 210 may include, for example, any of the following: a WWAN modem (e.g., a modem configured to communicate via E-UTRA 5G NR and / or any future WWAN communication standard), a WLAN modem (e.g., a modem configured to communicate via the IEEE 802.11 standard), a Bluetooth modem, an NTN modem, etc. In some aspects, the first wireless device 102 also includes one or more RF transceivers (hereinafter referred to as "RF transceiver 250"). In some cases, RF transceiver 250 may be referred to as an RF front end (RFFE). In some aspects, modem 210 also includes one or more processors, processing blocks, or processing elements (hereinafter referred to as "processor 212") and one or more storage blocks or elements (hereinafter referred to as "memory 214"). In some cases, processor 212 may implement and / or include predistortion manager 106. In other configurations, the processor 212 and / or memory 214 are implemented outside the modem 210 or otherwise separately from the modem.

[0037] In some respects, processor 212 may process any of the protocol stack layers associated with radio access technology (RAT). For example, processor 212 may process any of the application layer, packet layer, WLAN protocol stack layer (e.g., link or media access control (MAC) layer) and / or WWAN protocol stack layer (e.g., radio resource control (RRC) layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, and MAC layer).

[0038] Modem 210 may typically be configured to implement the physical (PHY) layer. For example, modem 210 may be configured to modulate packets and output the modulated packets to RF transceiver 250 for transmission over a wireless medium. Modem 210 is similarly configured to receive modulated packets received by RF transceiver 250 and demodulate the packets to provide demodulated packets. In addition to modulators and demodulators, modem 210 may also include digital signal processing (DSP) circuitry, automatic gain control (AGC), decoders, decoders, multiplexers, and / or demultiplexers (not shown).

[0039] For example, when in transmit mode, modem 210 may obtain data from a data source, such as an application processor. The data may be provided to a decoder, which encodes the data to provide encoded bits. The encoded bits may be mapped (e.g., using a selected modulation and decoding scheme) to points in a modulation constellation to provide modulated symbols. The modulated symbols may be mapped to, for example, a spatial stream or a space-time stream. The modulated symbols may be multiplexed, transformed via an inverse fast Fourier transform (IFFT) block, and subsequently provided to DSP circuitry for transmit windowing and filtering. The digital signal may be provided to digital-to-analog converter (DAC) 216. In some aspects involving beamforming, the modulated symbols in the corresponding spatial stream may be pre-decoded via a steering matrix before being provided to the IFFT block.

[0040] Modem 210 can be coupled to RF transceiver 250 via a transmit (TX) path 218 (also referred to as the transmit chain) for transmitting signals via one or more antennas 220 (hereinafter referred to as "antenna 220") and a receive (RX) path 222 (also referred to as the receive chain) for receiving signals via antenna 220. When TX path 218 and RX path 222 share antenna 220, the path can be coupled to antenna 220 via interface 224, which can include any RF device from a variety of suitable RF devices, such as antenna tuners, switches, duplexers, combiners, multiplexers, etc. For example, modem 210 can output digital in-phase (I) baseband signals and / or quadrature (Q) baseband signals representing corresponding symbols to DAC 216. In some examples, all or a subset of the elements illustrated as being included in RF transceiver 250 are implemented in a single chip or die. For example, in some configurations, all elements of the RF transceiver except antenna 220 are implemented on a single chip. In some other configurations, interface 224 or a portion thereof is also omitted from a single chip.

[0041] Receiving I or Q baseband analog signals from DAC 216, TX path 218 may include a baseband filter (BBF) 226, a mixer 228 (which may include one or more mixers), and a power amplifier (PA) 230. BBF 226 filters the baseband signal received from DAC 216, and mixer 228 mixes the filtered baseband signal with a transmit local oscillator (LO) signal to convert the baseband signal to a different frequency (e.g., up-converting from a baseband frequency to radio frequency). In some aspects, the frequency conversion process produces a sum and difference frequency between the LO frequency and the frequency of the baseband signal. This sum and difference frequency is called a beat frequency. Some beat frequencies are in the RF range, such that the signal output by mixer 228 is typically an RF signal, which can be amplified by PA 230 before being transmitted by antenna 220. Antenna 220 can transmit an RF signal that can be received at a second wireless device 104. Although a mixer 228 is illustrated, several mixers can be used to upconvert the filtered baseband signal to one or more intermediate frequencies and then upconvert the intermediate frequency signal to the frequency used for transmission.

[0042] RX path 222 may include a low-noise amplifier (LNA) 232, a mixer 234 (which may include one or more mixers), and a baseband filter (BBF) 236. RF signals received via antenna 220 (e.g., from the second wireless device 104) may be amplified by LNA 232, and mixer 234 mixes the amplified RF signal with a received local oscillator (LO) signal to convert the RF signal to a baseband frequency (e.g., down-convert the RF signal to a baseband frequency). The baseband signal output from mixer 234 may be filtered by BBF 236 and then converted to a digital I or Q signal by analog-to-digital converter (ADC) 238 for digital signal processing. Modem 210 may receive the digital I or Q signals and further process the digital signals, for example, demodulating the digital signals into information.

[0043] Some transceivers may employ a frequency synthesizer with a voltage-controlled oscillator (VCO) to generate a stable, tunable LO frequency with a specific tuning range. Therefore, the transmit LO frequency can be generated by frequency synthesizer 240, which can be buffered or amplified by an amplifier (not shown) and then mixed with a baseband signal in mixer 228. Similarly, the receive LO frequency can be generated by frequency synthesizer 240, which can be buffered or amplified by an amplifier (not shown) and then mixed with an RF signal in mixer 234. Separate frequency synthesizers may be used for TX path 218 and RX path 222.

[0044] When in receive mode, modem 210 can acquire the digitally converted signal via ADC 238 and RX path 222. For example, in modem 210, the digital signal can be provided to DSP circuitry configured to acquire the received signal, for example, by detecting the presence of the signal and estimating the initial timing and frequency offset. The DSP circuitry is also configured to digitally condition the digital signal, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correcting I / Q imbalance), and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuitry can be fed to AGC, which is configured to use information extracted from the digital signal (e.g., in one or more received training fields) to determine the appropriate gain. The output of the DSP circuitry can also be coupled to a demodulator configured to extract modulated symbols from the signal and, for example, calculate the log-likelihood ratio (LLR) for each bit location of each subcarrier in each spatial stream. The demodulator can be coupled to a decoder configured to process the LLR to provide decoded bits. Decoded bits from all spatial streams can be fed to a demultiplexer for demultiplexing. The demultiplexed bits can be descrambled and provided to the media access control layer (e.g., processor 212) for processing, evaluation, or interpretation.

[0045] As this article is about Figure 3A , Figure 3B and Figure 4 As further described herein, the output of PA 230 may be inductively coupled to RX path 222 to enable sampling of the PA output for predistortion training. Processor 212 (e.g., using predistortion manager 106) may perform aspects of predistortion training to set certain values ​​of one or more lookup tables (LUTs) 242 indicating predistortion model coefficients, as further described herein. In some aspects, LUT 242 may include AM-PM conversion parameters for predistortion. For example, during predistortion training, a training signal may be fed as input to PA 230, which outputs an amplified signal. Based on the amplified output signal of PA 230, a predistortion feedback signal is induced on the RX path via inductive coupling, as described herein. Figure 3A and Figure 3B As further described. The predistortion feedback signal indicates the nonlinearity of the PA and is digitally sampled via an ADC 238.

[0046] In the digital domain (e.g.), processor 212 (e.g., using predistortion manager 106) can compare the predistortion feedback signal with a training signal to characterize the nonlinearity of PA 230 and determine the predistortion coefficients for distortion compensation (such as digital predistortion (DPD)). Processor 212 can determine the predistortion coefficients of the inverse model of PA 230, which can be used to effectively eliminate certain nonlinear effects of PA 230 via predistortion. Processor 212 can precompute the inverse model across a range of possible inputs and store the results in LUT 242. LUT 242 can provide certain operating parameters for one or more components of TX path 218 to perform phase and / or amplitude correction of predistortion. For example, during transmit mode, modem 210 and / or processor 212 can apply DPD to the transmit signal in the digital domain and feed the predistorted transmit signal to TX path 218 via DAC 216. DPD can effectively eliminate (or compensate) the nonlinear effects of PA 230.

[0047] Modem 210 and / or processor 212 may control the transmission of signals via TX path 218 and / or the reception of signals via RX path 222. In some aspects, modem 210 and / or processor 212 may be configured to perform various operations, such as those associated with any of the methods described herein. Modem 210 and / or processor 212 may include a microcontroller, microprocessor, application processor, baseband processor, MAC processor, artificial intelligence (AI) processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic unit, discrete hardware component, or any combination thereof. Memory 214 may store data and program code (e.g., processor-readable instructions) for performing wireless communications as described herein. In some cases, memory 214 may be external to and / or incorporated into modem 210 and / or processor 212 (as illustrated, or where memory 214 is incorporated together with processor 212).

[0048] Figure 2 An example transceiver design is illustrated. It will be understood that other transceiver designs or architectures can be applied in conjunction with various aspects of this disclosure. For example, while the examples discussed herein utilize I and Q signals (e.g., quadrature modulation), those skilled in the art will understand that transceiver components can be configured to utilize any other suitable modulation, such as polarity modulation. Furthermore, circuit blocks can be... Figure 2 The configurations shown are arranged differently, and / or can be used as a supplement to or alternative to the depicted blocks to achieve... Figure 2 Other circuit blocks not shown.

[0049] Various aspects of this disclosure provide techniques for predistortion training via inductive coupling. Inductive coupling enables reduced power consumption and / or reduced circuit space in the predistortion training circuit.

[0050] Figure 3A and Figure 3B Example transceiver architectures 300A and 300B are illustrated, employing inductive coupling between receive path 318 and transmit path 322 for predistortion training. Architectures 300A and 300B are examples of architectures that can be implemented by RF transceiver 250. Reference Figure 3A The first transceiver architecture 300A includes a DAC 316, which feeds analog baseband signals to the transmit path 318, as described in this article. Figure 2 As described. DAC 316 and transmit path 318 can be respectively Figure 2 Examples of DAC 216 and TX path 218 are provided. Transmit path 318 includes BBF 326, mixer 328, and PA 330, which may also be examples of corresponding components of TX path 218. Transmit path 318 also includes a first inductor element 342 that enables inductive coupling between the output of PA 330 and receive path 322. In some aspects, the first inductor element 342 may be or include an inductor and / or transformer for impedance matching between transmit path 318 and an antenna (not shown) (such as antenna 220). PA 330 has an output 344 coupled to the first inductor element 342. In some aspects, PA 330 may be or include a multi-stage PA comprising at least a first-stage PA and a second-stage PA cascaded together, wherein the first-stage PA feeds or drives the second-stage PA. The predistortion training described herein can be applied to any PA in a multi-stage PA.

[0051] The first architecture 300A also includes a receive path 322, which feeds the analog baseband signal to the ADC 338, as described in this document. Figure 2 As described. Regarding Figure 3, the receiving path 322 and ADC 338 can be respectively Figure 2 Examples of RX path 222 and ADC 238 are provided. Receive path 322 includes LNA 332, mixer 334, and BBF 326, which can be examples of corresponding components of RX path 222. In this example, mixer 334 may include a voltage-mode mixer. Frequency synthesizer 340 may feed mixers 334 and 328, as described herein. Figure 2As described. The receive path 322 also includes a second inductor element 346, and in some cases, the receive path 322 may include a variable resistor element 348 coupled to the second inductor element 346. In some aspects, the second inductor element 346 and the variable resistor element 348 may be coupled to a reference node 354 (e.g., a supply voltage or reference potential). The second inductor element 346 may be or include an inductor coupled (e.g., directly connected) to the output 350 of the LNA 332. A first inductor element 342 may be arranged to be inductively coupled to the second inductor element 346. For example, the first inductor element 342 may be arranged in a circuit package to be positioned in a first layer above the second inductor element 346 in a second layer (not shown).

[0052] The variable resistive element 348 may be or includes a group of resistors having a variable resistance spanning a range of resistance values, for example, as described herein. Figure 5 As further described. The variable resistor element 348 may be coupled in parallel with the second inductor element 346, for example, such that the variable resistor element 348 is also coupled (e.g., directly connected or coupled) to the output 350 of the LNA 332. In some aspects, for example, because the resistive load of the variable resistor element 348 affects the current flowing through the second inductor element 346, the resistance of the variable resistor element 348 may be selected to adjust the mutual inductance between the first inductor element 342 and the second inductor element 346. For example, a lower resistance of the variable resistor element 348 may cause a decrease in the mutual inductance between the first inductor element 342 and the second inductor element 346, for example, because it allows less current to flow through the second inductor element 346. For example, a higher resistance of the variable resistor element 348 (relative to a lower resistance) may cause an increase in the mutual inductance between the first inductor element 342 and the second inductor element 346, for example, because it allows more current to flow through the second inductor element 346. In some aspects, the resistance of the variable resistor element 348 may be selected to adjust the quality factor of the second inductor element 346. In some respects, the resistance of the variable resistor element 348 can be selected to attenuate the predistortion feedback signal and suppress certain nonlinear effects of the receiving path 322 (such as the nonlinearity of the mixer 334).

[0053] In some respects, Figure 2 The processor 212 can adjust the attenuation applied to the signal carried through the receive path 322 depending on the transceiver's operating mode (such as training mode or communication mode). The processor 212 can adjust the first attenuation applied to the first signal received inductibly at the receive path 322 based on a first mode (e.g., training or calibration mode) via the variable resistance of the variable resistor element 348. The processor 212 can adjust the second attenuation applied to the second signal obtained via the receive path 322 (e.g., via an antenna) based on a second mode (e.g., communication mode).

[0054] During predistortion training (e.g., training or calibration mode), DAC 316 may output a specific training signal (e.g., based on inputs from modem 210 and / or predistortion manager 106) to characterize the distortion or nonlinearity of an amplifier (such as PA 330). In this example, PA 330 feeds an output signal to a first inductor 342, which is inductively coupled to a second inductor 346. When the output signal is fed into the first inductor 342, the inductive coupling between the first inductor 342 and the second inductor 346 allows a predistortion feedback signal to be induced in the second inductor 346. In some aspects, variable resistor element 348 may be configured to adjust the attenuation applied to the predistortion feedback signal obtained via the inductive coupling between the first inductor 342 and the second inductor 346. The attenuation applied to the predistortion feedback signal may be selectively applied to suppress certain nonlinear effects of the receive path 322 (such as nonlinearity of mixer 334). The variable resistor element 348 can be configured to adjust the mutual inductance between the first inductor element 342 and the second inductor element 346.

[0055] In some respects, as a complement to or alternative to DAC 316, one or more other components (e.g., mixer 328 and / or frequency synthesizer 340) may be used to output a training signal (e.g., based on input from modem 210 and / or predistortion manager 106). For example, the training signal may be derived via a local oscillator and / or frequency synthesizer without the need for DAC 316.

[0056] The predistortion feedback signal is fed to ADC 338, which performs digital signal processing on the predistortion feedback signal to characterize the distortion associated with PA 330. For example, Figure 2 The processor 212 (e.g., using predistortion manager 106) can determine one or more parameters of distortion compensation (e.g., DPD) associated with PA 330, at least in part, based on a predistortion feedback signal that can be inducted at receive path 322 during a first mode (e.g., training mode). The processor 212 can compare the predistortion feedback signal based on the output signal of PA 330 with a training signal used as input to PA 330. In some aspects, the parameters may be or include gain error and / or phase error associated with the predistortion feedback signal relative to the training signal. The parameters may be or include predistortion coefficients (e.g., memory polynomial coefficients of a generalized polynomial model of DPD), amplitude-to-phase modulation (AM-PM) conversion associated with PA 330, and / or amplitude-to-amplitude modulation (AM-AM) conversion associated with PA 330.

[0057] refer to Figure 3BThe first architecture 300A may represent certain aspects of the second architecture 300B. Typically, the second architecture 300B may be identical to the first architecture 300A, except that in the second architecture 300B, the mixer 334 of the receive path 322 may be or include a current-mode mixer. Therefore, as... Figure 3B As depicted, the receive path 322 includes a transconductance amplifier 352 coupled between the mixer 334 and the variable resistor element 348. The transconductance amplifier 352 is configured to convert the input voltage into an output current. In some cases, the transconductance amplifier 352 may be referred to as a current-mode transimpedance amplifier.

[0058] In some examples, no physical connection or trace is implemented to connect the nodes in the signal path between PA 330 and inductor 342 to receive path 322 or any other receive signal path. While TX path 318 and receive path 322 may be coupled to common baseband circuitry (e.g., modem 210) and / or common synthesizer circuitry (e.g., 340), in some examples, no additional physical connection or path may be implemented between the signal paths in transmit path 318 and receive path 322. In some aspects, the output of PA 330 may be electrically coupled to receive path 322 without any physical electrical connection (such as a signal trace, via, wire, etc.) between PA 330 and receive path 322. The output of PA 330 may be electrically coupled to receive path 322 via inductive coupling without any physical connection or without physical coupling to receive path 322. In some aspects, the output of PA 330 may not be physically coupled to receive path 322.

[0059] Figure 4 Examples are shown for use in transceivers (such as...) Figure 2An example architecture 400 for training and applying predistortion in an RF transceiver 250 is provided. In this example, architecture 400 includes in-phase and quadrature components such as mixer 428, mixer 434, BBF 426, and ADC 438. Architecture 400 also includes differential-mode components such as mixer 428, PA 430, LNA 432, mixer 434, BBF 426, and ADC 438. Architecture 400 includes impedance matching circuitry 470 configured to match the impedance between antenna 420 and transmit path 418 (a portion of which is depicted) and / or receive path 422. A first architecture 300A may represent architecture 400, wherein the output 444 of PA 430 is inductively coupled to receive path 422 via first inductor element 442 and second inductor element 446. In this example, due to the differential-mode architecture, the first inductor 442 is coupled between the differential outputs 444 of the PA 430, and the second inductor 446 is coupled between the differential outputs 450 of the LNA 432. A variable resistor 448 is also coupled between the differential outputs 450 of the LNA 432. Also in this example, the first inductor 442 is implemented as a transformer, for example, as a balun, which converts a balanced (differential) signal to a single-ended (common-mode) signal, such as... Figure 4 As shown. In some cases, the first inductor 442 can be implemented as a transformer that does not convert between single-ended and differential signals.

[0060] Architecture 400 includes one or more lookup tables (LUTs) 462, 464 (e.g., LUT 242), and one or more LUTs may include pre-distorted AM-PM conversion parameters and / or AM-AM conversion parameters. As discussed herein, Figure 2The processor 212 can pre-compute the inverse model of PA 430 across a range of possible inputs and store the results in LUTs 462, 464. LUTs 462, 464 can provide certain operating parameters for the frequency synthesizer 440 and / or voltage regulator 468 (e.g., a low dropout regulator (LDO)), which can be controlled via a DAC (not shown). LUT-based operation of the frequency synthesizer 440 (e.g., via the first LUT 462) can achieve pre-distortion phase correction via up-conversion, and LUT-based operation of the voltage regulator 468 (e.g., via the second LUT 464) can achieve pre-distortion amplitude correction. The voltage regulator 468 can be coupled to the center tap of the first inductor element 442 to feed a bias voltage to the first inductor element 442 and achieve distortion-compensated amplitude correction. In some aspects, the model used as the inverse model of PA can be or includes a Voltra series model, a memory polynomial (MP) model, and / or a generalized memory polynomial (GMP) model. Therefore, LUTs 462 and 464 can store operating parameters of frequency synthesizer 440 and / or voltage regulator 468 to apply certain distortion compensation to certain analog circuits (such as mixer 428 and first inductor element 442) across TX path 418.

[0061] Although this article describes inductive coupling used for training predistortion Figures 3A to 4 The examples depicted are for illustrative purposes, but aspects of this disclosure can be applied to training analog and / or digital predistortion using inductive coupling. In some aspects, certain distortion compensations described herein can be applied before the signal is fed to the amplifier (e.g., before amplification) and / or after the signal is output from the amplifier (e.g., after amplification), such as amplitude correction via the center tap of the first inductor element 442.

[0062] Will understand, Figures 3A to 4 The architecture illustrated is merely an example, and components have been omitted from the figures for simplicity. For instance, transmit paths 318, 418 and receive paths 322, 422 may be coupled to different antennas (e.g., 420) and / or impedance matching circuit 470. Furthermore, signal paths coupling modem 210 to mixer 428 (e.g., via DACs 216, 316 and BBFs 226, 326) are implemented but not illustrated.

[0063] Figure 5 An example resistor group 500 is shown that can be used in the receive path of a transceiver. Resistor group 500 can be... Figure 3A , Figure 3B and Figure 4Examples of variable resistive elements 348, 448. Resistor group 500 may include a first node 502, a second node 504, and multiple branches 506a-n coupled between the first node 502 and the second node 504. For example, nodes 502, 504 may be coupled between the differential outputs of LNA 432, or, as another example, may be coupled between a power supply or reference node and the output of LNA 332. Multiple branches 506a-n are arranged in parallel between the first node 502 and the second node 504. In this example, each of the multiple branches 506a-n includes one or more corresponding resistors 508a-n, 510a-n coupled in series with a corresponding switch 512a-n (e.g., a transistor). For example, first branch 506a includes one or more first resistors 508a, 510a coupled in series with a first switch 512a, and so on for any other corresponding branch 506b-n in the resistor group. Controller (e.g., Figure 2 The processor 212 can control which of the switches 512a-n is open or closed to select the resistance between the first node 502 and the second node 504. Therefore, the resistor group 500 can have a selective resistance value across a range of resistance values.

[0064] Therefore, inductive coupling for predistortion training offers various technical benefits and advantages. For example, inductive coupling allows for reduced power consumption and smaller circuit space in predistortion training circuits. Inductive coupling for predistortion training reduces auxiliary nonlinear effects in feedback circuits. For example, since the feedback path does not depend on any active devices that might affect noise and / or interference, inductive coupling for predistortion training can improve the signal quality of the feedback signal.

[0065] Figure 6 An example operation 600 for wireless communication is illustrated. Operation 600 may be performed, for example, by a wireless device (e.g., the first wireless device 102 in wireless communication system 100). In some aspects, operation 600 may be performed, for example, by a transceiver (e.g., RF transceiver 250), a modem (e.g., modem 210), and / or a processor (e.g., processor 212). Operation 600 may be implemented in one or more processors (e.g., Figure 2 Software components executed and running on the modem 210 and / or processor 212. Furthermore, the transmission and / or reception of signals by the wireless device in operation 600 may be, for example, by one or more antennas (e.g., Figure 2 Antenna 220) is used to achieve this. In some aspects, the transmission and / or reception of signals by the wireless device can be achieved via one or more processors (e.g., Figure 2 This is achieved by obtaining and / or outputting signals for receiving or transmitting through the bus interface of the modem 210 and / or processor 212.

[0066] Operation 600 may optionally begin at block 602, wherein the wireless device may obtain a first signal (e.g., a predistortion feedback signal) based on a second signal output from a first amplifier (e.g., PA 230, 330, 430) of a transmit path (e.g., transmit paths 218, 318), inductively coupled to the output of the first amplifier via a receive path (e.g., receive paths 222, 322, 422), the receive path including a variable resistor element (e.g., variable resistor element 348, 448) configured to adjust the attenuation applied to the first signal via a variable resistance adjustment of the variable resistor element. The wireless device may include, as described herein, […]. Figure 3A , Figure 3B and Figure 4 Any inductively coupled architecture described herein. The wireless device may adjust the attenuation applied to a first signal via a variable resistive element, for example, to control the nonlinear effects of the receive path on the feedback signal and / or the mutual inductance of the inductive coupling between the transmit and receive paths, as described herein. The first signal may be or include a predistortion feedback signal induced on the receive path via the inductive coupling between the first and second inductive elements. The second signal may be or include the output signal of a first amplifier based on a predistortion training signal fed to at least a portion of the transmit path including a first amplifier. In some aspects, the receive path may be configured in a first setting for sampling the predistortion feedback signal (e.g., in a training or calibration mode) and in a second setting for receiving a communication signal via an antenna (e.g., in a communication or receive mode). For example, the resistance of the variable resistive element may be adjusted to a first value when a signal for wireless communication is obtained via an antenna coupled to the receive path, and adjusted to a second value (different from the first value) when a predistortion feedback signal (such as the first signal) is obtained.

[0067] At block 604, the wireless device may determine one or more parameters of distortion compensation (such as digital predistortion (DPD)) associated with the first amplifier, at least in part, based on a first signal. In some aspects, the wireless device may determine one or more parameters of distortion compensation (e.g., DPD) based at least in part on a comparison between the first signal and a (DPD) training signal, which may be fed as input to at least the first amplifier. In some aspects, the one or more parameters include one or more of the following: one or more predistortion coefficients; an AM-PM conversion associated with the first amplifier; or an AM-AM conversion associated with the first amplifier.

[0068] At box 606, the wireless device may predistort a third signal (e.g., a communication signal) based at least in part on one or more parameters. For example, the wireless device may apply one or more parameters via a lookup table (e.g., LUT 462, 464) configured to apply phase and / or amplitude correction to the third signal, as described herein. Figure 4 As described. In some aspects, a predistorted signal may include: applying one or more distortion compensations, such as phase correction and / or amplitude correction, to the signal. For example, to predistort a third signal, phase correction may be applied to the third signal, for example, via a mixer that applies a phase shift to the third signal. In some aspects, a predistorted signal may include: applying all distortion compensations or a portion of the distortion compensations to the signal.

[0069] At box 608, the wireless device can amplify the pre-distorted third signal via a first amplifier. In some respects, the first amplifier can be used at or above the gain compression point. In some cases, some distortion compensation can be applied to the amplified third signal. For example, amplitude correction can be applied to the amplified third signal, for example via the bias voltage of a transformer, as described herein. Figure 4 As described.

[0070] At box 610, the wireless device may transmit the amplified third signal, for example, via an antenna (e.g., antennas 220, 420). For example, the wireless device may transmit the signal to another wireless communication device (e.g., Figure 1 The third signal may be transmitted by any of the second wireless devices (104) depicted in the diagram. The third signal may indicate (or carry) any information of various kinds, such as data and / or control information. In some cases, the signal may indicate (or carry) one or more packets or data blocks.

[0071] The aspects of this disclosure can be applied to any wireless communication device, such as a UE, wireless station, base station, access point, etc., that performs predistortion.

[0072] Figure 7 Various aspects of the example communication device 700 are described. In some aspects, the communication device 700 is a wireless communication device, as described above. Figure 1 and Figure 2 The first wireless device 102 is described.

[0073] The communication device 700 includes a processing system 702 coupled to a transceiver 708 (e.g., a transmitter and / or receiver). The transceiver 708 is configured to transmit and receive signals for the communication device 700 via an antenna 710, such as the various signals described herein. The processing system 702 may be configured to perform processing functions of the communication device 700, including processing signals received by the communication device 700 and / or to be transmitted by the communication device.

[0074] Processing system 702 includes one or more processors 720. In various aspects, the one or more processors 720 may be represented as... Figure 2 Either the described modem 210 and / or processor 212. One or more processors 720 are coupled to a computer-readable medium / memory 730 via a bus 706. In some aspects, the computer-readable medium / memory 730 is configured to store instructions (e.g., computer-executable code) that, when executed by one or more processors 720, cause one or more processors 720 to perform actions regarding... Figure 6 The described operation 600 or any aspect relating to the operation described herein. It should be noted that references to a processor performing the functions of communication device 700 may include one or more processors performing the functions of communication device 700. References to one or more processors performing multiple functions may include any one of those processors performing any one of the multiple functions.

[0075] In the depicted example, the computer-readable medium / memory 730 stores code (e.g., executable instructions) 731 for acquisition, code 732 for determination, code 733 for predistortion, code 734 for amplification, code 735 for transmission, code 736 for adjustment, or any combination thereof. Processing of codes 731 to 736 enables the communication device 700 to perform actions related to... Figure 6 The operation described is 600 or any aspect related to the operation described herein.

[0076] One or more processors 720 include circuitry configured to implement (e.g., execute) code stored in a computer-readable medium / memory 730, including circuitry 721 for acquisition, circuitry 722 for determination, circuitry 723 for pre-distortion, circuitry 724 for amplification, circuitry 725 for transmission, circuitry 726 for adjustment, or any combination thereof. Processing using circuitry 721 to 726 enables the communication device 700 to perform operations related to… Figure 6 The operation described is 600 or any aspect related to the operation described herein.

[0077] The various components of the communication device 700 can provide for performing tasks related to... Figure 6The components described are 600 or any aspect of the operation described herein. For example, components for sending, transmitting, or outputting for use in sending may include... Figure 2 The TX path 218 and / or antenna 220 of the first wireless device 102 illustrated herein, and / or Figure 7 The communication device 700 includes a transceiver 708 and an antenna 710. Components for receiving or acquiring data may include... Figure 2 The RX path 222 and / or antenna 220 of the first wireless device illustrated in the figure, and / or Figure 7 The transceiver 708 and antenna 710 of the communication device 700.

[0078] Components for acquiring, determining, pre-distorting, amplifying, and / or adjusting may include Figure 3A , Figure 3B and Figure 4 The inductor components are 342, 346, 442, and 446. Figure 2 , Figure 3A , Figure 3B and Figure 4 PA 230, 330, and 430; Figure 1 and 2 The predistortion manager 106 in the middle; and / or one or more processors, such as Figure 2 The modem 210 and / or processor 212 depicted therein, and / or Figure 7 The processor is 720.

[0079] Specific implementation examples are described in the following numbered clauses.

[0080] Aspect 1: An apparatus configured for wireless communication, the apparatus comprising: a receiving path including a variable resistive element; a transmitting path including a first amplifier having a first output inductively coupled to the receiving path; one or more memories; and one or more processors coupled to the one or more memories, the receiving path, and the transmitting path, wherein the one or more processors are configured to cause the apparatus to: obtain a first signal based on a second signal output by the first amplifier, via the receiving path inductively coupled to the first output of the first amplifier, wherein the variable resistive element is configured to adjust an attenuation applied to the first signal via a variable resistance of the variable resistive element; determine one or more parameters of digital predistortion (DPD) associated with the first amplifier based at least in part on the first signal; predistort a third signal based at least in part on the one or more parameters; amplify the predistorted third signal via the first amplifier; and transmit the amplified third signal.

[0081] Aspect 2: The apparatus according to aspect 1, wherein the transmitting path includes a first inductor element coupled to the first output of the first amplifier and inductively coupled to the receiving path.

[0082] Aspect 3: The apparatus according to aspect 2, wherein the first inductive element comprises a transformer.

[0083] Aspect 4: The apparatus according to aspect 2 or 3, wherein the receiving path includes a second inductor element, the second inductor element being inductively coupled to the first output terminal of the first amplifier via the first inductor element.

[0084] Aspect 5: The apparatus according to aspect 4, wherein the receiving path further includes a second amplifier having a second output coupled to the second inductor.

[0085] Aspect 6: The apparatus according to aspect 4 or 5, wherein the variable resistive element is coupled to the second inductive element.

[0086] Aspect 7: The apparatus according to aspect 6, wherein the variable resistive element comprises a resistor bank comprising a plurality of branches arranged in parallel, wherein each of the plurality of branches comprises a series-coupled resistive element and a switch.

[0087] Aspect 8: The apparatus according to aspect 6 or 7, wherein one or more processors are configured to cause the apparatus to adjust the attenuation applied to the first signal via the variable resistor element.

[0088] Aspect 9: The apparatus according to any one of Aspects 6 to 8, wherein the receiving path further comprises: a second amplifier having a second output coupled to the second inductor; and one or more mixers, wherein the second inductor and the variable resistor are coupled between the one or more mixers and the second output of the second amplifier.

[0089] Aspect 10: The apparatus according to aspect 9, wherein the receiving path further includes a transconductance amplifier coupled between the one or more mixers and the variable resistor element.

[0090] Aspect 11: The apparatus according to any one of aspects 1 to 10, wherein, in order to determine the one or more parameters, the one or more processors are configured to cause the apparatus to determine the one or more parameters of the DPD at least in part based on a comparison between the first signal and the DPD training signal.

[0091] Aspect 12: The apparatus according to any one of Aspects 1 to 11, wherein the one or more parameters include one or more of the following: one or more predistortion coefficients; amplitude-to-phase modulation (AM-PM) conversion associated with the first amplifier; or amplitude-to-amplitude modulation (AM-AM) conversion associated with the first amplifier.

[0092] Aspect 13: A method for wireless communication by a device, the method comprising: obtaining a first signal based on a second signal output from a first amplifier via a receiving path inductively coupled to the output of the first amplifier, the receiving path including a variable resistor element configured to adjust an attenuation applied to the first signal via a variable resistance of the variable resistor element; determining one or more parameters of digital predistortion (DPD) associated with the first amplifier based at least in part on the first signal; predistorting a third signal based at least in part on the one or more parameters; amplifying the predistorted third signal via the first amplifier; and transmitting the amplified third signal.

[0093] Aspect 14: According to the method of aspect 13, the transmitting path includes a first inductor element coupled to the first output of the first amplifier and inductively coupled to the receiving path.

[0094] Aspect 15: The method according to aspect 14, wherein the first inductor element comprises a transformer.

[0095] Aspect 16: The method according to aspect 14 or 15, wherein the receiving path includes a second inductor element, the second inductor element being inductively coupled to the first output terminal of the first amplifier via the first inductor element being inductively coupled to the second inductor element.

[0096] Aspect 17: According to the method of aspect 16, the receiving path further includes a second amplifier having a second output coupled to the second inductor.

[0097] Aspect 18: The method according to aspect 16 or 17, wherein the variable resistive element is coupled to the second inductive element.

[0098] Aspect 19: According to the method of aspect 18, the variable resistive element includes a resistor bank comprising a plurality of branches arranged in parallel, wherein each of the plurality of branches includes a series-coupled resistive element and a switch.

[0099] Aspect 20: The method according to aspect 18 or 19, the method further comprising: adjusting the attenuation applied to the first signal via the variable resistor element.

[0100] Aspect 21: The method according to any one of Aspects 18 to 20, wherein the receiving path further comprises: a second amplifier having a second output coupled to the second inductor; and one or more mixers, wherein the second inductor and the variable resistor are coupled between the one or more mixers and the second output of the second amplifier.

[0101] Aspect 22: According to the method of aspect 21, the receiving path further includes a transconductance amplifier coupled between the one or more mixers and the variable resistor element.

[0102] Aspect 23: The method according to any one of aspects 13 to 22, wherein determining the one or more parameters comprises: determining the one or more parameters of the DPD based at least in part on a comparison between the first signal and the DPD training signal.

[0103] Aspect 24: The method according to any one of Aspects 13 to 23, wherein the one or more parameters include one or more of the following: one or more predistortion coefficients; amplitude-to-phase modulation (AM-PM) conversion associated with the first amplifier; or amplitude-to-amplitude modulation (AM-AM) conversion associated with the first amplifier.

[0104] Aspect 25: An apparatus configured for wireless communication, the apparatus comprising: a receiving path; a transmitting path including a first amplifier having a first output inductively coupled to the receiving path and not physically coupled to the receiving path; one or more memories; and one or more processors coupled to the one or more memories, the receiving path, and the transmitting path, wherein the one or more processors are configured to cause the apparatus to: obtain a first signal based on a second signal output by the first amplifier, via the first output of the first amplifier inductively coupled to the first amplifier through the receiving path; determine one or more parameters of digital predistortion (DPD) associated with the first amplifier based at least in part on the first signal; predistort a third signal based at least in part on the one or more parameters; amplify the predistorted third signal via the first amplifier; and transmit the amplified third signal.

[0105] Aspect 26: An apparatus configured for wireless communication, the apparatus comprising: an antenna; and a receiving path comprising: a low-noise amplifier having an output and an input coupled to the antenna; a variable resistor directly connected to the output of the low-noise amplifier; an inductor directly connected to the output of the low-noise amplifier; and a down-conversion mixer coupled to the output of the low-noise amplifier.

[0106] Aspect 27: An apparatus configured for wireless communication, the apparatus comprising: a receiving path including a variable resistive element; one or more memories; and one or more processors coupled to the one or more memories and the receiving path, wherein the one or more processors are configured to cause the apparatus to: determine one or more parameters of a digital predistortion (DPD) based on a signal received by an inductor at the receiving path during a digital predistortion (DPD) training mode; and adjust the attenuation of the signal received by the inductor via a variable resistance of the variable resistive element based on the DPD training mode.

[0107] Aspect 28: An apparatus configured for wireless communication, the apparatus comprising: a receiving path; a transmitting path including a first amplifier having a first output inductively coupled to the receiving path; one or more memories; and one or more processors coupled to the one or more memories, the receiving path, and the transmitting path, wherein the one or more processors are configured to cause the apparatus to: obtain a first signal based on a second signal output by the first amplifier via the first output of the receiving path inductively coupled to the first amplifier; determine one or more parameters of digital predistortion (DPD) associated with the first amplifier based at least in part on the first signal; predistort a third signal based at least in part on the one or more parameters; amplify the predistorted third signal via the first amplifier; and transmit the amplified third signal.

[0108] Aspect 29: The apparatus according to aspect 28, wherein the transmitting path includes a first inductor element coupled to the first output of the first amplifier and inductively coupled to the receiving path.

[0109] Aspect 30: The apparatus according to aspect 29, wherein the first inductive element comprises a transformer.

[0110] Aspect 31: The apparatus according to aspect 29 or 30, wherein the receiving path includes a second inductor element, the second inductor element being inductively coupled to the first output terminal of the first amplifier via the first inductor element.

[0111] Aspect 32: The apparatus according to aspect 31, wherein the receiving path further includes a second amplifier having a second output coupled to the second inductor element.

[0112] Aspect 33: The apparatus according to aspect 31 or 32, wherein the receiving path further includes a variable resistance element coupled to the second inductor element, wherein the variable resistance element is configured to adjust the attenuation applied to the first signal via the variable resistance of the variable resistance element.

[0113] Aspect 34: The apparatus according to aspect 33, wherein the variable resistive element comprises a resistor bank comprising a plurality of branches arranged in parallel, wherein each of the plurality of branches comprises a series-coupled resistive element and a switch.

[0114] Aspect 35: The apparatus according to aspect 33 or 34, wherein one or more processors are configured to cause the apparatus to adjust the attenuation applied to the first signal via the variable resistor element.

[0115] Aspect 36: The apparatus according to any one of Aspects 33 to 35, wherein the receiving path further comprises: a second amplifier having a second output coupled to the second inductor; and one or more mixers, wherein the second inductor and the variable resistor are coupled between the one or more mixers and the second output of the second amplifier.

[0116] Aspect 37: The apparatus according to aspect 36, wherein the receiving path further includes a transconductance amplifier coupled between the one or more mixers and the variable resistor element.

[0117] Aspect 38: An apparatus according to any one of aspects 28 to 37, wherein, in order to determine the one or more parameters, the one or more processors are configured to cause the apparatus to determine the one or more parameters of the DPD at least in part based on a comparison between the first signal and the DPD training signal.

[0118] Aspect 39: The apparatus according to any one of Aspects 28 to 38, wherein the one or more parameters include one or more of the following: one or more predistortion coefficients; amplitude-to-phase modulation (AM-PM) conversion associated with the first amplifier; or amplitude-to-amplitude modulation (AM-AM) conversion associated with the first amplifier.

[0119] Aspect 40: An apparatus configured for wireless communication, the apparatus comprising: a receiving path including a variable resistive element; one or more memories; and one or more processors coupled to the one or more memories and the receiving path, wherein the one or more processors are configured to cause the apparatus to: determine one or more parameters for distortion compensation based on a first signal received by an inductor at the receiving path during a first mode; and adjust a first attenuation applied to the first signal received by the inductor via a variable resistance of the variable resistive element based on the first mode.

[0120] Aspect 41: The apparatus according to aspect 40, wherein the receiving path further includes an inductive element configured to inductively receive the first signal.

[0121] Aspect 42: The apparatus according to aspect 40 or 41, wherein the one or more processors are configured to cause the apparatus to adjust a second attenuation applied to a second signal obtained via the receiving path based on a second mode.

[0122] Aspect 43: The apparatus according to aspect 41 or 42, wherein the receiving path further comprises: an amplifier having an output coupled to the inductor; and one or more mixers, wherein the inductor and the variable resistor are coupled between the one or more mixers and the output of the amplifier.

[0123] Aspect 44: The apparatus according to aspect 43, wherein the receiving path further includes a transconductance amplifier coupled between the one or more mixers and the variable resistor element.

[0124] Aspect 45: An apparatus according to any one of aspects 40 to 44, wherein, in order to determine the one or more parameters, the one or more processors are configured to cause the apparatus to determine the one or more parameters of the distortion compensation based at least in part on a comparison between the first signal and the training signal.

[0125] Aspect 46: The apparatus according to any one of Aspects 40 to 45, wherein the variable resistive element comprises a resistor bank comprising a plurality of branches arranged in parallel, wherein each of the plurality of branches comprises a series-coupled resistive element and a switch.

[0126] Aspect 47: A method for wireless communication by a device, the method comprising: obtaining a first signal based on a second signal output from a first amplifier via a transmission path, inductively coupled to an output of the first amplifier via a reception path; determining one or more parameters of digital predistortion (DPD) associated with the first amplifier based at least in part on the first signal; predistorting a third signal based at least in part on the one or more parameters; amplifying the predistorted third signal via the first amplifier; and transmitting the amplified third signal.

[0127] Aspect 48: An apparatus comprising components for performing the method according to any one of aspects 13 to 24 or 47.

[0128] Aspect 49: A non-transitory computer-readable medium comprising computer-executable instructions that, when executed by one or more processors of a processing system, cause the processing system to perform the method according to any one of aspects 13 to 24 or 47.

[0129] Aspect 50: A computer program product embodied on a computer-readable storage medium, the computer program product comprising code for performing the method according to any one of aspects 13 to 24 or 47.

[0130] Additional Notes The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein do not limit the scope, applicability, or aspects set forth in the claims. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, the function and arrangement of the elements discussed may be changed without departing from the scope of this disclosure. Various processes or components may be omitted, substituted, or added as appropriate in the various examples. For example, the described methods may be performed in a different order than described, and various actions may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement an apparatus or practice. Additionally, the scope of this disclosure is intended to cover such apparatuses or methods practiced using other structures, functionalities, or structures and functionalities that complement or replace the various aspects of this disclosure set forth herein. It should be understood that any aspect of the disclosure herein may be embodied by one or more elements of the claims.

[0131] The various exemplary logic blocks, modules, and circuits described in this disclosure may be implemented or executed using a microcontroller, microprocessor, general-purpose processor, digital signal processor (DSP), artificial intelligence processor, application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic unit, discrete hardware component, or any combination thereof, designed to perform the functions described herein. While a general-purpose processor may be a microprocessor, in alternative embodiments, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors working in conjunction with a DSP core, a system-on-a-chip (SoC), or any other such configuration.

[0132] As used in this article, the phrase “at least one of” in a list of items refers to any combination of those items, including a single member. For example, “at least one of a, b, or c” is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0133] As used herein, the term “determine” encompasses a wide variety of actions. For example, “determine” can include calculation, computation, processing, derivation, research, lookup (e.g., searching in a table, database, or other data structure), identification, and similar actions. Additionally, “determine” can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), etc. Furthermore, “determine” can include parsing, selecting, identifying, mapping, applying, picking, building, etc. As used herein, unless otherwise stated, “coupled to” and “coupled with” generally encompass direct coupling and indirect coupling (e.g., including intermediate aspects of coupling). For example, stating that a processor is coupled to memory allows for direct coupling or coupling via intermediate aspects such as a bus.

[0134] The methods disclosed herein include one or more actions for implementing the methods. These actions may be interchanged without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and / or use of a particular action may be modified without departing from the scope of the claims. Furthermore, the various operations of the methods described above can be performed by any suitable component capable of performing the corresponding function. Components may include various hardware and / or software components and / or modules, including but not limited to circuits, ASICs, or processors.

[0135] The following claims are not intended to be limited to the aspects shown herein, but should be given the full scope consistent with the language of the claims. References to singular elements are not intended to mean “only one” (unless specifically stated as “only one”), but rather “one or more”. Unless otherwise specified, definite articles (e.g., “the” or “described”) subsequently used with an element (e.g., “processor”) are not intended to give that element a singular meaning (e.g., “only one”). For example, unless otherwise specified, references to elements (e.g., “processor”, “controller”, “memory”, “transceiver”, “antenna”, “the processor”, “the controller”, “the memory”, “the transceiver”, “the antenna”, etc.) should be understood to refer to one or more elements (e.g., “one or more processors”, “one or more controllers”, “one or more memories”, “one or more transceivers”, etc.). The terms “set” and “group” are intended to include one or more elements and may be used interchangeably with “one or more”. In the case of references to one or more elements performing a function (e.g., steps of a method), one element may perform all the functions, or more than one element may collectively perform those functions. When more than one element performs these functions together, each function does not need to be performed by every single element (e.g., different functions can be performed by different elements), and / or each function does not need to be performed by only one element overall (e.g., different elements can perform different sub-functions of a function). Similarly, when referring to one or more elements configured to cause another element (e.g., a device) to perform a function, one element may be configured to cause another element to perform all functions, or more than one element may be jointly configured to cause another element to perform these functions. Unless otherwise specifically stated, the term "some" refers to one or more. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are currently or hereafter known to those skilled in the art are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended to be offered to the public, whether or not such disclosure is explicitly stated in the claims.

Claims

1. An apparatus configured for wireless communication, the apparatus comprising: Receive path; A transmission path, the transmission path including a first amplifier having a first output terminal inductively coupled to the receiving path; One or more memory units; and One or more processors, said one or more processors coupled to said one or more memories, said receive path and said transmit path, said one or more processors being configured to cause the device to: A first signal is obtained by inductively coupling the second signal output by the first amplifier to the first output terminal of the first amplifier via the receiving path; One or more parameters of the digital predistortion (DPD) associated with the first amplifier are determined, at least in part, based on the first signal; The third signal is predistorted at least in part based on one or more of the parameters mentioned above; The pre-distorted third signal is amplified by the first amplifier; as well as Send the amplified third signal.

2. The apparatus of claim 1, wherein the transmitting path includes a first inductor coupled to the first output of the first amplifier and inductively coupled to the receiving path.

3. The apparatus of claim 2, wherein the first inductor element comprises a transformer.

4. The apparatus of claim 2, wherein the receiving path includes a second inductor element, the second inductor element being inductively coupled to the first output terminal of the first amplifier via the first inductor element.

5. The apparatus of claim 4, wherein the receiving path further comprises a second amplifier having a second output terminal coupled to the second inductor.

6. The apparatus of claim 4, wherein the receiving path further comprises a variable resistor element coupled to the second inductor element, wherein the variable resistor element is configured to adjust the attenuation applied to the first signal via the variable resistance of the variable resistor element.

7. The apparatus of claim 6, wherein the variable resistive element comprises a resistor bank comprising a plurality of branches arranged in parallel, wherein each of the plurality of branches comprises a resistive element and a switch coupled in series.

8. The apparatus of claim 6, wherein the one or more processors are configured to cause the apparatus to adjust the attenuation applied to the first signal via the variable resistor element.

9. The apparatus of claim 6, wherein the receiving path further comprises: A second amplifier, the second amplifier having a second output terminal coupled to the second inductor; and One or more mixers, wherein the second inductor and the variable resistor are coupled between the one or more mixers and the second output of the second amplifier.

10. The apparatus of claim 9, wherein the receiving path further comprises a transconductance amplifier coupled between the one or more mixers and the variable resistor element.

11. The apparatus of claim 1, wherein, in order to determine the one or more parameters, the one or more processors are configured to cause the apparatus to determine the one or more parameters of the DPD at least in part based on a comparison between the first signal and the DPD training signal.

12. The apparatus of claim 1, wherein the one or more parameters include one or more of the following: One or more predistortion coefficients; The amplitude-to-phase modulation (AM-PM) conversion associated with the first amplifier; or Amplitude-to-amplitude modulation (AM-AM) conversion associated with the first amplifier.

13. An apparatus configured for wireless communication, the apparatus comprising: A receiving path, the receiving path including a variable resistor element; One or more memory units; and One or more processors, said one or more processors coupled to said one or more memories and said receiving path, said one or more processors being configured to cause the device to: One or more parameters for distortion compensation are determined based on the first signal received by the inductor at the receiving path during the first mode; as well as Based on the first mode, the first attenuation of the first signal received by the inductor is adjusted by the variable resistance of the variable resistor element.

14. The apparatus of claim 13, wherein the one or more processors are configured to cause the apparatus to adjust a second attenuation applied to a second signal obtained via the receiving path based on a second mode.

15. The apparatus of claim 13, wherein the receiving path further comprises an inductive element configured to inductively receive the first signal.

16. The apparatus of claim 15, wherein the receiving path further comprises: An amplifier having an output terminal coupled to the inductor element; and One or more mixers, wherein the inductive element and the variable resistor element are coupled between the one or more mixers and the output of the amplifier.

17. The apparatus of claim 16, wherein the receiving path further comprises a transconductance amplifier coupled between the one or more mixers and the variable resistor element.

18. The apparatus of claim 13, wherein, in order to determine the one or more parameters, the one or more processors are configured to cause the apparatus to determine the one or more parameters of the distortion compensation based at least in part on a comparison between the first signal and the training signal.

19. The apparatus of claim 13, wherein the variable resistive element comprises a resistor bank comprising a plurality of branches arranged in parallel, wherein each of the plurality of branches comprises a series-coupled resistive element and a switch.

20. A method for wireless communication by a device, the method comprising: The first signal is obtained by inductively coupling the second signal output by the first amplifier in the transmitting path to the output of the first amplifier via the receiving path. One or more parameters of the digital predistortion (DPD) associated with the first amplifier are determined, at least in part, based on the first signal; The third signal is predistorted at least in part based on one or more of the parameters mentioned above; The pre-distorted third signal is amplified by the first amplifier; as well as Send the amplified third signal.

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