Interpolated power tracking and input power adjustment based on peak-to-average power ratio

Abstract

Some aspects of this disclosure relate, in general, to electronic components, and more particularly to radio frequency front-end (RFFE) circuits. One exemplary apparatus may include a controller configured to determine a first and second calibration point of an amplifier, the first calibration point being associated with a first supply voltage of the amplifier, and a second calibration point being associated with a second supply voltage of the amplifier, and to determine an operating point of the amplifier, which is associated with a third supply voltage, by interpolating based on the first and second calibration points. The apparatus may also include an interface configured to control a power supply to provide a third supply voltage associated with the operating point of the amplifier.

Description

[Technical Field]

[0001] (Cross-reference of related applications)

[0001] This application claims priority to U.S. Patent Application No. 18 / 340,480, filed on 23 June 2023, which is incorporated herein by reference. [Background technology]

[0002] Technical field

[0002] Some aspects of the present disclosure relate to electronic components in general, and more particularly to radio frequency front-end (RFFE) circuits.

[0003] Explanation of related technologies

[0003] Electronic devices include computing devices such as desktop computers, notebook computers, tablet computers, smartphones, wearable devices such as smartwatches, and internet servers. These various electronic devices provide human users with information, entertainment, social interaction, security, safety, productivity, transportation, manufacturing, and other services. Many of these various electronic devices rely on wireless communication for many of their functions. Wireless communication systems and devices are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, and broadcast. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems (e.g., Long Term Evolution (LTE) systems, or New Radio (NR) systems). Wireless devices may include transceivers for processing signals for reception and / or transmission. Transceivers may include one or more transmit chains and one or more receive chains, and these transmit and receive chains may include one or more amplifiers, one or more filters, and one or more mixers. The transmit chain may also include a power amplifier for amplifying the input signal for signal transmission. [Overview of the project]

[0004]

[0004] The systems, methods, and devices of this disclosure each have several embodiments, and none of these embodiments alone contribute to the desired attributes. Without limiting the scope of this disclosure as expressed in the following claims, some features are briefly described here. After reviewing this description, and especially after reading the section titled “Modes for Carrying Out the Invention,” it will be understood how the features of this disclosure provide the advantages described herein.

[0005]

[0005] Some aspects of the present disclosure relate to devices for wireless communications. The devices generally include a controller configured to determine a first calibration point and a second calibration point of an amplifier, the first calibration point being associated with a first supply voltage of the amplifier, and the second calibration point being associated with a second supply voltage of the amplifier, and to determine an operating point of the amplifier, which is associated with a third supply voltage, by interpolating based on the first calibration point and the second calibration point. The devices may also include an interface configured to control a power supply to provide a third supply voltage associated with the operating point of the amplifier.

[0006]

[0006] Some aspects of the present disclosure relate to methods for wireless communication. The methods generally include: determining a first calibration point and a second calibration point of an amplifier, the first calibration point being associated with a first supply voltage of the amplifier and the second calibration point being associated with a second supply voltage of the amplifier; determining an operating point of the amplifier, which is associated with a third supply voltage, by interpolating based on the first and second calibration points; and controlling a power supply to provide a third supply voltage associated with the operating point of the amplifier.

[0007]

[0007] Some aspects of the present disclosure relate to devices for wireless communications. The devices generally include a control circuit configured to determine a first peak-to-average power ratio (PAPR) associated with a first input signal to an amplifier for signal transmission, a second PAPR associated with the output signal of the amplifier, and a second input signal to the amplifier based on the first and second PAPRs. The devices may also include an interface configured to control a transmit chain to generate a second input signal to the amplifier.

[0008]

[0008] Some aspects of the present disclosure relate to methods for wireless communication. The methods generally include determining a first PAPR associated with a first input signal to an amplifier for signal transmission, determining a second PAPR associated with an output signal to the amplifier, determining a second input signal to the amplifier based on the first and second PAPRs, and controlling a transmission chain to generate the second input signal to the amplifier.

[0009]

[0009] To achieve the above-mentioned and related objectives, one or more embodiments include features that are fully described below and, in particular, pointed out in the claims. The following description and accompanying drawings describe in detail specific exemplary features of one or more embodiments. However, these features represent only a small number of the various methods that may employ the principles of the various embodiments. [Brief explanation of the drawing]

[0010]

[0010] More specific descriptions than those briefly summarized above may be given by referring to embodiments shown in part in the accompanying drawings, so that the features described above may be understood in more detail. However, it should be noted that the accompanying drawings show only specific embodiments of the disclosure and should not be considered to limit the scope of the disclosure, as other similarly effective embodiments may be recognized in this description. [Figure 1]

[0011] A diagram of an exemplary wireless communication network in which aspects of the present disclosure may be implemented. [Figure 2]

[0012] A block diagram of an exemplary access point (AP) and an exemplary user terminal in which aspects of the present disclosure may be implemented. [Figure 3]

[0013] A block diagram of an exemplary transceiver front end in which aspects of the present disclosure may be implemented. [Figure 4]

[0014] A diagram showing an exemplary interpolation power tracking amplifier circuit according to some aspects of the present disclosure. [Figure 5]

[0015] A graph showing calibration points associated with an amplifier according to some aspects of the present disclosure. [Figure 6]

[0016] A flowchart showing an exemplary operation of interpolation power tracking according to some aspects of the present disclosure. [Figure 7]

[0017] Figures 7A, 7B, and 7C are diagrams showing the responses of an amplifier under different operating conditions according to some aspects of the present disclosure. [Figure 8]

[0018] A flowchart showing an exemplary operation for peak-to-average power ratio (PAPR)-based input power adjustment according to some aspects of the present disclosure. [Figure 9]

[0019] A diagram showing a PAPR determination circuit according to some aspects of the present disclosure.

[0011]

[0020] For ease of understanding, the same reference numbers are used to designate the same elements common to the figures where possible. Consideration has been given to the fact that elements disclosed in one aspect may be beneficially utilized in other aspects without specific recitation.

Mode for Carrying Out the Invention

[0013]

[0022] Some aspects of this disclosure relate to automatic input power adjustment using the peak-to-average power ratio (PAPR). For example, the input power may be adjusted based on the estimated error of the input power required to operate the amplifier in compression. The error may be estimated using the PAPR by comparing the PAPR of the input signal before digital pre-distortion with the PAPR associated with the output of the amplifier.

[0014] Exemplary wireless communication system

[0023] Figure 1 shows a wireless communication system 100 having an access point 110 and a user terminal 120, which is capable of carrying out the embodiments of this disclosure. For simplicity, only one access point 110 is shown in Figure 1. An access point (AP) is generally a fixed station that communicates with a user terminal and may also be called a base station (BS), evolved Node B (eNB), next generation Node B (gNB), or any other term. A user terminal (UT) may be fixed or mobile and may also be called a mobile station (MS), access terminal, user equipment (UE), station (STA), client, wireless device, or any other term. A user terminal may be a wireless device such as a cellular phone, personal digital assistant (PDA), handheld device, wireless modem, laptop computer, tablet, or personal computer.

[0015]

[0024] The access point 110 can communicate with one or more user terminals 120 at any given moment over the downlink and uplink. The downlink (i.e., forward link) is the communication link from the access point to the user terminal, and the uplink (i.e., reverse link) is the communication link from the user terminal to the access point. User terminals can also communicate with other user terminals peer-to-peer. The system controller 130 is coupled to the access point and performs coordination and control for the access point.

[0016]

[0025] The wireless communication system 100 employs multiple transmitting antennas and multiple receiving antennas for data transmission over downlink and uplink. The access point 110 uses N to achieve transmit diversity for downlink transmission and / or receive diversity for uplink transmission. ap It can be equipped with this many antennas.u A set of selected user terminals 120 may receive downlink transmissions and transmit uplink transmissions. Each selected user terminal may transmit user-specific data to and / or receive user-specific data from the access point. Generally, each selected user terminal may be equipped with one or more antennas (i.e., N ut ≥1). N u Each selected user terminal may have the same or different number of antennas.

[0017]

[0026] The wireless communication system 100 may be a time division duplex (TDD) system or a frequency division duplex (FDD) system. In the case of a TDD system, the downlink and uplink share the same frequency band. In the case of an FDD system, the downlink and uplink use multiple different frequency bands. The wireless communication system 100 may also utilize a single carrier or multiple carriers for transmission. Each user terminal 120 may be equipped with a single antenna (for example, to reduce costs) or multiple antennas (for example, if additional costs can be supported).

[0018]

[0027] In some embodiments, the user terminal 120 or access point 110 may include a controller that determines the operating point of the amplifier using interpolation based on a calibration point. In some embodiments, the controller may use the peak-to-average power ratio (PAPR) to estimate the error in the input power required to operate the amplifier in compression and adjust the input power accordingly.

[0019]

[0028] Figure 2 shows a block diagram of the wireless communication system 100, consisting of an access point 110 and two user terminals 120m and 120x. Access point 110 is N ap It is equipped with antennas 224a to 224ap. User terminal 120m is N ut,mequipped with antennas 252ma to 252mu, user terminal 120x has N ut,x antennas 252xa to 252xu. Access point 110 is a transmitting entity for the downlink and a receiving entity for the uplink. Each user terminal 120 is a transmitting entity for the uplink and a receiving entity for the downlink. As used herein, a "transmitting entity" is an independently operating device or device capable of transmitting data via a frequency channel, and a "receiving entity" is an independently operating device or device capable of receiving data via a frequency channel. In the following description, the subscript "dn" represents the downlink, the subscript "up" represents the uplink, and N up user terminals are selected for simultaneous transmission on the uplink, and N dn user terminals are selected for simultaneous transmission on the downlink, but N up may be equal to N dn or not equal, and N up and N dn may be a static value or may change for each scheduling interval. Beam steering, beamforming, or some other spatial processing technique may be used at the access point and / or user terminal.

[0020]

[0029] On the uplink, in each user terminal 120 selected for uplink transmission, TX data processor 288 receives traffic data from data source 286 and control data from controller 280. TX data processor 288 processes (e.g., encodes, interleaves, and modulates) traffic data {d up } for the user terminal based on the coding and modulation scheme associated with the rate selected for the user terminal, and N ut,m data symbol streams {s upThe transceiver front end (TX / RX) 254 (also known as the radio frequency front end (RFFE)) receives and processes each symbol stream (e.g., converts to analog, amplifies, filters, and frequency upconverts) to generate the uplink signal. The transceiver front end 254 also provides, for example, an RF switch for transmit diversity. ut,m The uplink signal can be routed to one of the antennas. The controller 280 can control the routing within the transceiver front end 254. The memory 282 can store data and program code for the user terminal 120 and can interface with the controller 280.

[0021]

[0030] N up Each of these user terminals 120 can be scheduled for simultaneous transmission over the uplink. Each of these user terminals sends its processed set of symbol streams to the access point over the uplink.

[0022]

[0031] At access point 110, N ap These antennas 224a to 224ap transmit all N on the uplink. up Uplink signals are received from individual user terminals. For receive diversity, the transceiver front end 222 may select signals received from one of several antennas 224 for processing. Signals received from multiple antennas 224 may be combined for extended receive diversity. The access point's transceiver front end 222 also performs processing that is complementary to that performed by the user terminal's transceiver front end 254 and provides a recovered uplink data symbol stream. The recovered uplink data symbol stream is the data symbol stream {s} transmitted by the user terminal. upThis is an estimate of}. The RX data processor 242 processes the recovered uplink data symbol stream (e.g., demodulate, deinterleave, and decode) according to the rate used for that stream in order to obtain the decoded data. The decoded data for each user terminal or access terminal may be fed to a data sink (e.g., data sink 244, data sink 272m, or data sink 272x) for storage and / or to a controller for further processing.

[0023]

[0032] On the downlink, at access point 110, the TX data processor 210 is scheduled for downlink transmission. dn The TX data processor 210 receives traffic data for each user terminal from data source 208, control data from controller 230, and possibly other data from scheduler 234. Various types of data may be transmitted over different transport channels. The TX data processor 210 processes (e.g., encodes, interleaves, and modulates) the traffic data for each user terminal based on the rate selected for that user terminal. The TX data processor 210 receives N ap N should be transmitted from one of these antennas. dn A downlink data symbol stream may be provided for one or more of the user terminals. The transceiver front end 222 receives and processes the symbol stream (e.g., converts to analog, amplifies, filters, and frequency upconverts) to generate the downlink signal. The transceiver front end 222 also provides, for example, an RF switch for transmit diversity. ap Downlink signals can be routed to one or more of the antennas 224. The controller 230 can control routing within the transceiver front end 222. Memory 232 can store data and program code related to the access point 110 and can interface with the controller 230.

[0024]

[0033] In each user terminal 120, N ut,m The antennas 252 receive downlink signals from the access point 110. For receive diversity at the user terminal 120, the transceiver front end 254 may select signals received from one or more of the antennas 252 for processing. Signals received from multiple antennas 252 may be combined for extended receive diversity. The user terminal's transceiver front end 254 also performs processing that is complementary to that performed by the access point's transceiver front end 222, providing a recovered downlink data symbol stream. The RX data processor 270 processes the recovered downlink data symbol stream (e.g., demodulates, deinterleaves, and decodes) to obtain decoded data for the user terminal.

[0025]

[0034] In some embodiments, a controller (e.g., controller 230 or controller 280) may determine the operating point of the amplifier using interpolation based on a calibration point. In some embodiments, the controller may use the peak-to-average power ratio (PAPR) to estimate the error in the input power required to operate the amplifier in compression and adjust the input power accordingly.

[0026]

[0035] Figure 3 is a block diagram of an exemplary transceiver front end 300, including the transceiver front ends 222 and 254 of Figure 2, which are capable of carrying out the embodiments of this disclosure. The transceiver front end 300 includes a transmit (TX) path 302 (also known as a “transmit chain”) for transmitting signals through one or more antennas, and a receive (RX) path 304 (also known as a “receive chain”) for receiving signals through antennas. When the TX path 302 and the RX path 304 share antenna 303, these paths may be connected to the antenna via an interface 306 which may include any of a variety of suitable radio frequency (RF) devices, such as switches, duplexers, diplexers, and multiplexers.

[0027]

[0036] The TX path 302, which receives an in-phase (I) or quadrature (Q) baseband analog signal from the digital-to-analog converter (DAC) 308, may include a baseband filter (BBF) 310, a mixer 312, a driver amplifier (DA) 314, and a power amplifier (PA) 316. The BBF 310, mixer 312, and DA 314 may be contained within a radio frequency integrated circuit (RFIC). In some cases, the PA 316 may be external to the RFIC.

[0028]

[0037] The BBF310 filters the baseband signal received from the DAC308, and the mixer 312 mixes the filtered baseband signal with a transmit local oscillator (LO) signal to convert the target baseband signal to a different frequency (e.g., upconvert from baseband to RF). This frequency conversion process generates a sum and difference frequency between the LO frequency and the frequency of the target signal. The sum and difference frequencies are called "beat frequencies." The beat frequencies are generally in the RF range, and therefore the signal output by the mixer 312 is generally an RF signal, which can be amplified by the DA314 and / or by the PA316 before transmission by the antenna 303. Although only one mixer 312 is shown, several mixers may be used to upconvert the filtered baseband signal to one or more intermediate frequencies, and then upconvert the intermediate frequency (IF) signal to a frequency for transmission.

[0029]

[0038] In some embodiments, the operating point of the PA316 may be determined using interpolation based on the calibration point. The error in the input power required to operate the PA316 in compression may be estimated using the peak-to-average power ratio (PAPR), and the input power may be adjusted accordingly.

[0030]

[0039] The RX path 304 includes a low-noise amplifier (LNA) 322, a mixer 324, and a baseband filter (BBF) 326. The LNA 322, mixer 324, and BBF 326 may be contained within a radio frequency integrated circuit (RFIC), which may or may not be the same RFIC containing the TX path components. The RF signal received via antenna 303 may be amplified by the LNA 322, and the mixer 324 mixes the amplified RF signal with a received local oscillator (LO) signal to convert the target RF signal to a different baseband frequency (i.e., down-convert). The baseband signal output by the mixer 324 may be filtered by the BBF 326 before being converted to digital I or Q signals by an analog-to-digital converter (ADC) 328 for digital signal processing.

[0031]

[0040] A particular RFFE may employ a frequency synthesizer with a variable frequency oscillator (e.g., a voltage-controlled oscillator (VCO) or a digitally controlled oscillator (DCO)) to generate a stable, tuneable LO with a specific tuning range. Thus, the transmit LO frequency can be generated by the TX frequency synthesizer 318 and buffered or amplified by the amplifier 320 before being mixed with the baseband signal in the mixer 312. Similarly, the receive LO frequency can be generated by the RX frequency synthesizer 330 and buffered or amplified by the amplifier 332 before being mixed with the RF signal in the mixer 324.

[0032] Exemplary Techniques for Efficient Power Tracking

[0041] In some embodiments, the power supply for PA316 may be implemented using efficient power tracking (e.g., EPT). In some embodiments, the power supply may adjust the supply voltage for PA316 so that the supply voltage is based on the target output power at antenna 303.

[0033]

[0042] Figure 4 shows an exemplary efficient power tracking amplifier circuit 400. As shown, PA316 can amplify an input signal 412. The input signal 412 may represent a common-mode (I) signal or a quadrature-phase (Q) signal (e.g., from a transceiver / front-end 300). In some cases, the input signal may form an input to a digital pre-distortion (DPD) circuit 421. The DPD circuit 421 may perform pre-distortion on the input signal to increase the linearity associated with the output signal of PA316. The pre-distorted input signal may be supplied to a gain circuit 404 (e.g., to apply gain to the pre-distorted input signal in either the digital or analog domain), and the gain circuit 404 generates an RF input signal for PA316.

[0034]

[0043] The input signal 412 may be supplied to a transmit reference waveform generator 490, which provides a signal representing the distribution of the input signal 412. The PA316 generates an amplified output signal 414 based on the input signal 412. In some embodiments, a feedback receiver (FBRx) 450 may be used to perform amplifier response measurements. For example, the output of the PA316 may be coupled to an FBRx chain (similar to the RX path 304 and ADC328, for example) and provide a digital signal to a controller 452 (e.g., a baseband processor) for analysis of the amplifier response. For example, the FBRx may be used to measure the PAPR at the output of the PA316, as will be described in more detail herein. As shown in the figures, the controller 452 may control a PA supply voltage controller 410 for the PA316 via an interface 489 (e.g., a communication bus). Furthermore, the controller 452 may control a gain circuit 404 via a gain controller 492. In some cases, the controller 452 may also control a lookup table for the DPD.

[0035]

[0044] Conventional power supplies can operate with increased (e.g., peak) efficiency when operating at a specific calibration point (e.g., the operating point at which the amplifier is determined to operate in compression). Multiple calibration points may be identified during calibration, each covering a certain power range (e.g., a power range of approximately 2 dB).

[0036]

[0045] Figure 5 is a graph showing calibration points 504, 506, 508, and 510 associated with PA316. PA316 may have different operating curves depending on the supply voltage. For example, operating curve 520 may correspond to a Vdd of 2.1V, operating curve 522 may correspond to a Vdd of 2.4V, operating curve 524 may correspond to a Vdd of 3.0V, and operating curve 526 may correspond to a Vdd of 3.3V. Operating curves 520, 522, 524, and 526 can be determined during calibration (for example, by sweeping the input power to PA316 and measuring the amplifier's response). At calibration points 504, 506, 508, and 510 (also called "compression points"), PA316 operates in compression.

[0037]

[0046] As shown in the figure, each of the calibration points 504, 506, 508, and 510 can be associated with a specific supply voltage Vdd for the PA316 on the compression curve 502. That is, each calibration point can be at the intersection of the compression curve 502 and the operating curve associated with the PA supply voltage. For example, calibration point 504 may be associated with a Vdd of 2.1V, calibration point 506 with a Vdd of 2.4V, calibration point 508 with a Vdd of 3.0V, and calibration point 510 with a Vdd of 3.3V. The PA316 can operate at peak efficiency when operating in compression at one of the calibration points.

[0038]

[0047] In existing EPT implementations, the transmitter automatic gain control (TxAGC) setting operates with power back-off from the calibration point (e.g., back-off from calibration point 510 as indicated by arrow 560). When the transmit power is not at a particular calibration point, the same amplifier bias (e.g., supply voltage) associated with the calibration point may be used, but the amplifier input signal digital gain may be backed off to meet the transmit power (e.g., resulting in an amplifier operating with lighter compression). For example, if operating at calibration point 510 (e.g., with a supply voltage of 3.3V, corresponding to an input voltage Vin of approximately 1.3V and an output voltage (output voltage, Vout) of 4.9V), and the output voltage is reduced to 4.3V, the same supply voltage of 3.3V may be applied. The input voltage Vin may be reduced to approximately 1.1V to supply the output voltage of 4.3V, and as a result, the PA316 operates at operating point 512, which is not on the compression curve 502. Therefore, the PA316 no longer operates with compression, which can reduce amplifier efficiency. Power backoff results in power efficiency losses.

[0039]

[0048] Some aspects of this disclosure relate to power supplies that provide continuous adjustment of amplifier bias with finer resolution than at least some conventional implementations. As described, existing power supplies with EPTs may use discrete amplifier biases set based on calibration points. This disclosure relates to techniques for identifying the operating point and associated amplifier supply voltage using interpolation based on calibration points. For example, the operating point 532 may be identified using interpolation based on calibration points 508, 510. The operating point 532 may correspond to a supply voltage for PA316 between 3.0V (e.g., associated with calibration point 508) and 3.3V (e.g., associated with calibration point 510). Thus, the power supply (e.g., power supply 410) may generate a supply voltage for the operating point such that PA316 operates on the operating curve 530 (e.g., TxAGC is set based on curve 530). Thus, instead of operating at operating point 512, PA316 may operate at operating point 532 in compression (e.g., on the compression curve 502).

[0040]

[0049] Figure 6 is a flowchart illustrating an exemplary operation 600 for wireless communication according to several aspects of the present disclosure. For example, operation 600 may be performed by a controller such as controller 230.

[0041]

[0050] Operation 600 begins in block 602 with the controller determining a first calibration point (e.g., calibration point 508) and a second calibration point (e.g., calibration point 510) of an amplifier (e.g., PA316). The first calibration point may be associated with a first supply voltage (e.g., Vdd of 3.0V), and the second calibration point may be associated with a second supply voltage (e.g., Vdd of 3.3V). In some embodiments, the first calibration point may be determined based on the amplifier (e.g., PA) supply voltage and the voltage at the amplifier input.

[0042]

[0051] In block 604, the controller determines the operating point of the amplifier (e.g., operating point 532) by interpolating based on the first and second operating points. The operating point may be associated with a third supply voltage (e.g., between the first and second supply voltages).

[0043]

[0052] In block 606, the controller controls the power supply to provide the amplifier with a third supply voltage associated with an operating point. In some embodiments, the operating point is associated with the input power to the amplifier (e.g., Vin). The controller may control the transmit chain to generate an input signal to the amplifier based on the input power to satisfy a specific output power for signal transmission.

[0044]

[0053] In some embodiments, the operating point includes the compression point of the amplifier. Each of the first and second calibration points may include a compression point on the amplifier's operating curve (e.g., operating curve 522 or operating curve 526). In some embodiments, the operating point may be determined based on the interpolated power of the two calibration points for the amplifier.

[0045] Exemplary Techniques for Input Power Error Estimation Using Peak-to-Average Power Ratio

[0054] In some cases, the input power (Pin) error can be estimated for Pin tuning by comparing the amplifier's response to calibration data. However, as will be discussed in more detail herein, estimating the Pin error can be difficult when there is a large power backoff for signal transmission or when the transmit PAPR is small. Some aspects of this disclosure provide an automated Pin tuning technique using the peak-to-average power ratio (PAPR) (e.g., referred to as PAPR-AP). For example, some aspects provide a PAPR-based input power error estimation technique used to tune the Pin of an amplifier.

[0046]

[0055] Figures 7A, 7B, and 7C show the amplifier's response under different operating conditions. Figure 7A shows the measured amplifier response when operating under compression (indicated by the measured response curve 722), Figure 7B shows the measured amplifier response under undercompression (indicated by the measured response curve 724), and Figure 7C shows the measured amplifier response under overcompression (indicated by the measured response curve 726). The amplifier's response can be measured by sweeping the input power to the amplifier and measuring the amplifier's response to the sweep.

[0047]

[0056] The amplifier's response can vary over frequency and temperature. For example, PA316 may be undercompressed under high-temperature conditions (e.g., high temperatures), as shown in Figure 7B, while it may be overcompressed under low-temperature conditions, as shown in Figure 7C. In some cases, a DPD (e.g., input signaling distortion in the digital domain) can be used to compensate for the nonlinearity of PA316. Graphs 702, 704, and 706 also show DPD curves 720 that can be used to perform input signal distortion (e.g., using a DPD circuit 421 as described with respect to Figure 4). Graphs 702, 704, and 706 also show the PA's response to a DPD (e.g., shown by curves 728, 730, and 732), which can be measured using an FBRx.

[0048]

[0057] The pins of the PA316 can be adjusted to configure the PA316 to operate at the same target compression point under various conditions. The DPD provides a linear system with appropriate pin adjustments and can therefore meet the error vector magnitude (EVM) and / or adjacent channel leakage ratio (ACLR) performance specifications. However, as described, it can be difficult to estimate the input power error for operation in compression due to the difficulty in detecting the amplifier response (e.g., by simply comparing the amplifier response with calibration data). For example, if the transmitted waveform used has a small PAPR and / or a large digital backoff power, the amplifier response measurement samples may be concentrated in a region of operation (e.g., region 780) that does not allow for proper estimation of the pin error (e.g., because the measurement samples do not provide information about the amplifier response in the higher power region).

[0049]

[0058] In some embodiments, PAPR is used as a metric for estimating the input power error. Based on PAPR, Pin may be iteratively adjusted. For example, the input power may be iteratively adapted based on the difference between the measured PAPR (e.g., measured based on a feedback receiver (FBRx)) and the transmitter (Tx) reference capture (e.g., referred herein as the “transmit PAPR”, the PAPR prior to the DPD).

[0050]

[0059] As shown in Graph 702, when operating at the target compression point, the FBRx measured PAPR may be the same as the transmitted PAPR (e.g., the PAPR difference is zero). As shown in Graph 704, if there is undercompression, the FBRx measured PAPR may be higher than the transmitted PAPR, resulting in a positive PAPR difference. As shown in Graph 706, if there is overcompression, the FBRx PAPR may be lower than the transmitted PAPR, resulting in a negative PAPR difference.

[0051]

[0060] To determine the PAPR difference, the transmit PAPR may be measured before the DPD (e.g., at the input of the DPD circuit 421), and the PAPR may be measured at the output of PA316 (e.g., via FBRx). The two measured PAPRs may be compared to identify the PAPR difference. If the PAPR difference is positive (e.g., FBRx PAPR is higher than the transmit PAPR), the amplifier may be undercompressed. This allows Pin to be increased. If the PAPR difference is negative (e.g., FBRx PAPR is lower than the transmit PAPR), the amplifier may be undercompressed. This allows Pin to be decreased.

[0052]

[0061] Figure 8 is a flowchart illustrating an exemplary operation 800 for wireless communication according to several embodiments of the present disclosure. For example, operation 800 may be performed by a control circuit such as a controller 230, and in some embodiments by a PAPR decision circuit such as the PAPR decision circuit 900 in Figure 9.

[0053]

[0062] Operation 800 begins in block 802 with the control circuit determining a first PAPR associated with a first input signal of the amplifier for signal transmission. For example, the PAPR may be associated with the input signal before the DPD (e.g., at the input of the DPD circuit 421).

[0054]

[0063] In block 804, the control circuit determines a second PAPR associated with the amplifier's output signal. For example, the second PAPR may be determined based on feedback signaling received from a feedback receiver (e.g., receiver 450) coupled between the amplifier's output and the control circuit.

[0055]

[0064] In block 806, the control circuit determines the second input signal of the amplifier based on the first PAPR and the second PAPR. For example, the second input signal may be determined to be smaller than the first input signal based on the second PAPR being larger than the first PAPR. The second input signal may be determined to be larger than the first input signal based on the second PAPR being smaller than the first PAPR. The second input signal may be determined to operate the amplifier in compression. In block 808, the control circuit controls the transmit chain to generate the second input signal of the amplifier.

[0056]

[0065] Some aspects of this disclosure provide interpolation EPT techniques that, on average, offer higher power efficiency compared to at least some conventional EPT techniques. For example, the aspects described herein enable the PA to operate at the target compression point. Furthermore, the PAPR-based error estimation techniques described herein are more robust to use than at least some conventional input power error estimation techniques. PAPR-based error estimation techniques also reduce calibration time (for example, because calibration cannot be used for Pin estimation). EPT and PAPR-based Pin error estimation techniques are less complex than existing EPT and Pin error estimation techniques (for example, involving fewer calculations).

[0057]

[0066] Figure 9 shows a PAPR determination circuit 900 according to several aspects of the present disclosure. The PAPR determination circuit 900 may include a power measurement circuit 902 that receives I and Q signals and outputs a power measurement signal. For example, the power measurement circuit 902 may provide a power measurement to a peak detector 904. The peak detector 904 may detect a peak associated with the power measurement, and this peak may be provided to a maximum peak detector circuit 906. The maximum peak detector circuit 906 may output the highest peak within a measurement window (e.g., within a slot based on a slot boundary trigger signal 940) to a PAPR generator 910. The power measurement circuit 902 may also provide an average power measurement to the PAPR generator 910. The PAPR generator 910 may generate a signal representing the PAPR based on the maximum peak and average power measurement. As shown in the figure, the power measurement circuit 902, the peak detector 904, the maximum peak detector circuit 906, and the PAPR generator 910 may be reset via the slot boundary trigger signal 940.

[0058] Exemplary aspects

[0067] In addition to the various embodiments described above, certain combinations of these embodiments are within the scope of this disclosure, some of which are described in detail below.

[0059]

[0068] Embodiment 1: A device for wireless communication, comprising: a controller configured to determine a first calibration point and a second calibration point of an amplifier, the first calibration point being associated with a first supply voltage of the amplifier and the second calibration point being associated with a second supply voltage of the amplifier, and to determine an operating point of the amplifier, which is associated with a third supply voltage, by interpolating based on the first calibration point and the second calibration point; and an interface configured to control a power supply to provide a third supply voltage associated with the operating point of the amplifier.

[0060]

[0069] Embodiment 2: The apparatus according to Embodiment 1, wherein the third supply voltage is between the first supply voltage and the second supply voltage.

[0061]

[0070] Embodiment 3: The apparatus according to Embodiment 1 or 2, wherein the operating point is associated with input power to an amplifier, and the interface is further configured to control the transmission chain to generate an input signal to the amplifier based on the input power in order to satisfy a specific output power for signal transmission.

[0062]

[0071] Embodiment 4: The apparatus according to any one of Embodiments 1 to 3, wherein the operating point includes the compression point of the amplifier.

[0063]

[0072] Embodiment 5: The apparatus according to any one of Embodiments 1 to 4, wherein each of the first calibration point and the second calibration point includes a compression point on the operating curve of the amplifier.

[0064]

[0073] Embodiment 6: The apparatus according to any one of Embodiments 1 to 5, wherein the amplifier includes a power amplifier.

[0065]

[0074] Embodiment 7: A method for wireless communication, comprising: determining a first calibration point and a second calibration point of an amplifier, the first calibration point being associated with a first supply voltage of the amplifier and the second calibration point being associated with a second supply voltage of the amplifier; determining an operating point of the amplifier being associated with a third supply voltage by interpolating based on the first and second calibration points; and controlling a power supply to provide a third supply voltage associated with the operating point of the amplifier.

[0066]

[0075] Embodiment 8: The method according to Embodiment 7, wherein the third supply voltage is between the first supply voltage and the second supply voltage.

[0067]

[0076] Embodiment 9: The method according to Embodiment 7 or 8, wherein the operating point is associated with the input power to the amplifier, and the method further comprises controlling the transmission chain to generate an input signal to the amplifier based on the input power in order to satisfy a specific output power for signal transmission.

[0068]

[0077] Embodiment 10: The method according to any one of Embodiments 7 to 9, wherein the operating point includes the compression point of the amplifier.

[0069]

[0078] Embodiment 11: The method according to any one of Embodiments 7 to 10, wherein each of the first operating point and the second operating point includes a compression point on the operating curve of the amplifier.

[0070]

[0079] Embodiment 12: The method according to any one of Embodiments 7 to 11, wherein the amplifier includes a power amplifier.

[0071]

[0080] Embodiment 13: Apparatus for wireless communication comprising: a control circuit configured to determine a first peak-to-average power ratio (PAPR) associated with a first input signal of an amplifier for signal transmission, a second PAPR associated with an output signal of the amplifier, and a second input signal of the amplifier based on the first and second PAPRs; and an interface configured to control a transmission chain to generate a second input signal of the amplifier.

[0072]

[0081] Embodiment 14: The apparatus according to Embodiment 13, wherein a second PAPR is determined based on feedback signaling received from a feedback receiver coupled between the output of the amplifier and the control circuit.

[0073]

[0082] Embodiment 15: The apparatus according to Embodiment 14, wherein the first input signal includes a signal at the input of a digital pre-distortion (DPD) circuit coupled to the input of an amplifier.

[0074]

[0083] Embodiment 16: The apparatus according to any one of embodiments 13 to 15, wherein the second input signal is determined to be smaller than the first input signal based on the fact that the second PAPR is larger than the first PAPR.

[0075]

[0084] Embodiment 17: The apparatus according to any one of embodiments 13 to 16, wherein the second input signal is determined to be greater than the first input signal based on the fact that the second PAPR is smaller than the first PAPR.

[0076]

[0085] Embodiment 18: The apparatus according to any one of embodiments 13 to 17, wherein the control circuit is configured to determine a second input signal for the amplifier to operate in compression.

[0077]

[0086] Embodiment 19: The apparatus according to any one of embodiments 13 to 18, wherein the control circuit comprises a PAPR determination circuit configured to determine at least one of a first PAPR or a second PAPR.

[0078]

[0087] Embodiment 20: A method for wireless communication, comprising: determining a first peak-to-average power ratio (PAPR) associated with a first input signal of an amplifier for signal transmission; determining a second PAPR associated with an output signal of the amplifier; determining a second input signal of the amplifier based on the first and second PAPRs; and controlling a transmission chain to generate the second input signal of the amplifier.

[0079]

[0088] Embodiment 21: The method according to Embodiment 20, wherein a second PAPR is determined based on feedback signaling received from a feedback receiver.

[0080]

[0089] Embodiment 22: The method according to Embodiment 21, wherein the first input signal includes a signal at the input of a digital pre-distortion (DPD) circuit coupled to the input of an amplifier.

[0081]

[0090] Embodiment 23: The method according to any one of embodiments 20 to 22, wherein the second input signal is determined to be smaller than the first input signal based on the fact that the second PAPR is larger than the first PAPR.

[0082]

[0091] Embodiment 24: The method according to any one of embodiments 20 to 23, wherein the second input signal is determined to be greater than the first input signal based on the fact that the second PAPR is smaller than the first PAPR.

[0083]

[0092] Embodiment 25: The method according to any one of embodiments 20 to 24, wherein a second input signal is determined to cause the amplifier to operate in compression.

[0084] Additional considerations

[0093] Within the scope of this disclosure, the term “exemplary” is used to mean “serving as an example, illustration, or representation.” No implementation or aspect described herein as “exemplary” should necessarily be construed as being preferable or advantageous to any other aspect of this disclosure. Similarly, the term “aspect” does not require that all aspects of this disclosure include the features, advantages, or modes of operation discussed. The term “bonded” is used herein to refer to a direct or indirect bond between two objects. For example, if object A is in physical contact with object B, and object B is in contact with object C, then object A and object C may still be considered bonded to each other, even if object A and object C are not in direct physical contact with each other. For example, a first object may be bonded to a second object even if the first object is not in any direct physical contact with the second object. The terms “circuit” and “circuitry” are used broadly and include hardware implementations of both electrical devices and conductors that, when connected and configured, enable the implementation of the functions described herein, without limitation on the type of electronic circuit.

[0085]

[0094] As used herein, the term “determining” encompasses a wide range of actions. For example, “determining” may include calculating, calculating, processing, deriving, investigating, searching (e.g., searching in a table, database, or other data structure), and confirming. It may also include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and resolving, selecting, choosing, and establishing.

[0086]

[0095] The apparatus and methods described in embodiments for carrying out the invention are shown in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements”). The various operations or methods described above may be carried out by any preferred means capable of performing the corresponding function. These means may include, but are not limited to, various hardware components and / or software components, including circuits, application-specific integrated circuits (ASICs), or processors, and / or various hardware modules and / or software modules. Generally, where operations are shown in the drawings, those operations may have corresponding equivalent means-plus-function components with similar numbering.

[0087]

[0096] One or more of the components, steps, features, and / or functions described herein may be reconfigured and / or combined into a single component, step, feature, or function, or may be implemented in several components, steps, or functions. Additional elements, components, steps, and / or functions may also be added without departing from the features disclosed herein. Apparatus, devices, and / or components described herein may be configured to implement one or more of the methods, features, or steps described herein.

[0088]

[0097] It should be understood that the specific order or hierarchy of steps in the disclosed method is an example of an exemplary process. It should also be understood that the specific order or hierarchy of steps in the method may be rearranged based on design preferences. The appended claims for the method illustrate various step elements in a sample order and are not intended to be limited to the specific order or hierarchy presented unless specifically enumerated herein.

[0089]

[0098] The foregoing explanations are provided so that any person skilled in the art may practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to a person skilled in the art, and the general principles defined herein may also be applied to other embodiments. Therefore, the claims are not limited to the embodiments shown herein, but should be given the entire scope consistent with the language of the claims, and a singular reference to an element is intended to mean "one or more" rather than "only one" unless otherwise specified. Unless otherwise specified, the term "several" refers to one or more. A phrase referring to an enumeration of items, "at least one of," refers to any combination of those items, including a single element. For example, “at least one of a, b, or c” is intended to cover at least any combination of a, b, c, ab, ac, bc, and abc, and multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other order of a, b, and c). All structural and functional equivalents of elements in various aspects described throughout this disclosure, whether known to those skilled in the art or to become known later, are expressly incorporated by reference herein and are intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be made public, regardless of whether such disclosure is expressly enumerated in the claims. No element of a claim should be construed under Section 112(f) of the United States Patent Act unless that element is expressly enumerated using the phrase “means for…” or, in the case of a method claim, unless that element is enumerated using the phrase “steps for…”.

[0090]

[0099] It should be understood that the claims are not limited to the exact configurations and components illustrated above. Various modifications, changes, and variations may be made to the configuration, operation, and details of the methods and apparatus described above without departing from the claims.

Claims

1. A device for wireless communication, Determine a first calibration point and a second calibration point of an amplifier, wherein the first calibration point is associated with a first supply voltage of the amplifier and the second calibration point is associated with a second supply voltage of the amplifier. A controller configured to determine the operating point of the amplifier, which is associated with a third supply voltage, by performing interpolation based on the first and second calibration points, A device comprising: an interface configured to control a power supply to provide the third supply voltage associated with the operating point of the amplifier.

2. The apparatus according to claim 1, wherein the third supply voltage is between the first supply voltage and the second supply voltage.

3. The operating point is associated with the input power to the amplifier, The apparatus according to claim 1, wherein the interface is further configured to control the transmission chain to generate an input signal to the amplifier based on the input power in order to satisfy a specific output power for signal transmission.

4. The apparatus according to claim 1, wherein the operating point includes the compression point of the amplifier.

5. The apparatus according to claim 1, wherein each of the first calibration point and the second calibration point includes a compression point on the operating curve of the amplifier.

6. The apparatus according to claim 1, wherein the amplifier includes a power amplifier.

7. A method for wireless communication, Determining a first calibration point and a second calibration point of an amplifier, wherein the first calibration point is associated with a first supply voltage of the amplifier and the second calibration point is associated with a second supply voltage of the amplifier, The operation point of the amplifier, which is associated with the third supply voltage, is determined by interpolation based on the first and second calibration points. A method comprising controlling a power supply to provide the third supply voltage associated with the operating point of the amplifier.

8. The method according to claim 7, wherein the third supply voltage is between the first supply voltage and the second supply voltage.

9. The operating point is associated with the input power to the amplifier, The method according to claim 7, further comprising controlling the transmission chain to generate an input signal to the amplifier based on the input power in order to satisfy a specific output power for signal transmission.

10. The method according to claim 7, wherein the operating point includes the compression point of the amplifier.

11. The method according to claim 7, wherein each of the first operating point and the second operating point includes a compression point on the operating curve of the amplifier.

12. The method according to claim 7, wherein the amplifier includes a power amplifier.

13. A device for wireless communication, Determine the first peak-to-average power ratio (PAPR) associated with the first input signal of the amplifier for signal transmission. Determine the second PAPR associated with the output signal of the amplifier. A control circuit configured to determine a second input signal for the amplifier based on the first PAPR and the second PAPR, A device comprising an interface configured to control a transmission chain to generate the second input signal of the amplifier.

14. The apparatus according to claim 13, wherein the second PAPR is determined based on feedback signaling received from a feedback receiver coupled between the output of the amplifier and the control circuit.

15. The apparatus according to claim 14, wherein the first input signal includes a signal at the input of a digital pre-distortion (DPD) circuit coupled to the input of the amplifier.

16. The apparatus according to claim 13, wherein the second input signal is determined to be smaller than the first input signal based on the fact that the second PAPR is larger than the first PAPR.

17. The apparatus according to claim 13, wherein the second input signal is determined to be greater than the first input signal based on the fact that the second PAPR is smaller than the first PAPR.

18. The apparatus according to claim 13, wherein the control circuit is configured to determine the second input signal in order to operate the amplifier in compression.

19. The apparatus according to claim 13, wherein the control circuit comprises a PAPR determination circuit configured to determine at least one of the first PAPR or the second PAPR.

20. A method for wireless communication, To determine a first peak-to-average power ratio (PAPR) associated with a first input signal of an amplifier for signal transmission, To determine a second PAPR associated with the output signal of the amplifier, The second input signal of the amplifier is determined based on the first PAPR and the second PAPR. A method comprising controlling a transmission chain to generate the second input signal of the amplifier.

21. The method according to claim 20, wherein the second PAPR is determined based on feedback signaling received from a feedback receiver.

22. The method according to claim 21, wherein the first input signal includes a signal at the input of a digital pre-distortion (DPD) circuit coupled to the input of the amplifier.

23. The method according to claim 20, wherein the second input signal is determined to be smaller than the first input signal based on the fact that the second PAPR is larger than the first PAPR.

24. The method according to claim 20, wherein the second input signal is determined to be greater than the first input signal based on the fact that the second PAPR is smaller than the first PAPR.

25. The method according to claim 20, wherein the second input signal is determined to cause the amplifier to operate in compression.

Images