Opportunistic calibration using variable sample averaging

Abstract

The present disclosure provides an apparatus for wireless communications. The apparatus includes one or more processors; a transmit path coupled to the one or more processors comprising: a first frequency synthesizer configured to consume a first amount of power, wherein the first frequency synthesizer is configured to feed a first local oscillator (LO) signal that comprises a first frequency tone with a first phase noise profile; and a feedback receive path selectively coupled to the transmit path comprising: a second frequency synthesizer configured to consume a second amount of power less than the first amount of power, wherein: the second frequency synthesizer is configured to feed a second LO signal that comprises a second frequency tone with a second phase noise profile; the second frequency tone is offset from the first frequency tone; and the second phase noise profile comprises a wider phase profile than the first phase noise profile.

Description

Qualcomm Ref. No.: 2402797WO 1 OPPORTUNISTIC CALIBRATION USING VARIABLE SAMPLE AVERAGING CROSS REFERENCE TO RELATED APPLICATION

[0001] The present Application for Patent claims priority to and benefit of Indian Patent Application No. 202441032105, filed April 23, 2024, which is hereby expressly incorporated by reference herein in its entirety. BACKGROUND Field of the Disclosure

[0002] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for performing a calibration for a radio frequency (RF) circuit using variable sample averaging. Description of Related Art

[0003] Wireless communications systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, or other similar types of services. These wireless communications systems may employ multiple-access technologies capable of supporting communications with multiple users by sharing available wireless communications system resources with those users. Wireless communication devices may communicate radio frequency (RF) signals via any of various 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 Mobility (GSM), Bluetooth, Bluetooth Low Energy (BLE), ZigBee, wireless local area network (WLAN) RATs (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802.11 specifications), any future RAT, and / or the like.

[0004] In certain cases, a wireless communications device is equipped with an RF transceiver (also referred to as an RF front-end) for communicating RF signals. In general, a baseband signal is modulated to convey information using a modulation technique, such as phase-shift keying (PSK) or any other suitable modulation technique. In a transmit mode, the RF transceiver is responsible for multiplying the baseband signal with an RF carrier signal that is transmitted over the air (e.g., a wireless communication channel). Such an operation is called upconversion. In a receive mode, the RF transceiver converts D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 2 a received RF signal to the baseband signal. Such an operation is called downconversion. The received baseband signal then can be demodulated into the information encoded at a transmitter. The RF transceiver may include a cascade of components in a transmit path (e.g., transmit chain) and a receive path (e.g., receive chain), respectively. The cascade of components may include, for example, one or more of attenuators, switches, couplers, filters, mixers, amplifiers, frequency synthesizers, oscillators, antenna tuners, duplexers, diplexers, detectors, etc.

[0005] Although wireless communications systems have made great technological advancements over many years, challenges still exist. For example, complex and dynamic environments can still attenuate or block signals between wireless transmitters and wireless receivers. Accordingly, there is a continuous desire to improve the technical performance of wireless communications systems, including, for example: improving speed and data carrying capacity of communications, improving efficiency of the use of shared communications mediums, reducing power used by transmitters and receivers while performing communications, improving reliability of wireless communications, avoiding redundant transmissions and / or receptions and related processing, improving the coverage area of wireless communications, increasing the number and types of devices that can access wireless communications systems, increasing the ability for different types of devices to intercommunicate, increasing the number and type of wireless communications mediums available for use, and the like. Consequently, there exists a need for further improvements in wireless communications systems to overcome the aforementioned technical challenges and others. SUMMARY

[0006] One aspect provides an apparatus configured for wireless communications. The apparatus includes one or more processors configured to output at least one calibration signal; a transmit path coupled to the one or more processors, the transmit path comprising: a first frequency synthesizer covering a first area and configured to consume a first amount of power; and one or more first mixers coupled to the first frequency synthesizer, wherein: the first frequency synthesizer is configured to feed a first local oscillator (LO) signal to the one or more first mixers; and the first LO signal comprises a first frequency tone with a first phase noise profile; and a feedback receive path selectively coupled to the transmit path, the feedback receive path comprising: a second frequency synthesizer covering a second area and configured to consume a second D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 3 amount of power, wherein: the second area is smaller than the first area; and the second amount of power is less than the first amount of power; and one or more second mixers coupled to the second frequency synthesizer, wherein: the second frequency synthesizer is configured to feed a second LO signal to the one or more second mixers; the second LO signal comprises a second frequency tone with a second phase noise profile; the second frequency tone is offset from the first frequency tone; and the second phase noise profile comprises a wider phase profile than the first phase noise profile.

[0007] Another aspect provides a method for wireless communications by an apparatus. The apparatus includes one or more memories comprising processor- executable instructions (e.g., for performing the method); one or more processors; a transmit path coupled to the one or more processors; and a feedback receive path selectively coupled to the transmit path. The method includes generating at least one calibration signal; sending, through the transmit path, the at least one calibration signal; obtaining, from the feedback receive path, at least one output signal corresponding to the at least one calibration signal, wherein the at least one output signal is offset in frequency from the at least one calibration signal; performing an averaging of the at least one output signal, wherein the averaging comprises computing one or more average noise values from the at least one output signal based at least in part on a number of digitized samples; determining one or more filter parameters based on the averaging; and filtering one or more communication signals using a filter configured to operate in accordance with the one or more filter parameters.

[0008] Other aspects provide: one or more apparatuses operable, configured, or otherwise adapted to perform any portion of any method described herein (e.g., such that performance may be by only one apparatus or in a distributed fashion across multiple apparatuses); one or more non-transitory, computer-readable media comprising instructions that, when executed by one or more processors of one or more apparatuses, cause the one or more apparatuses to perform any portion of any method described herein (e.g., such that instructions may be included in only one computer-readable medium or in a distributed fashion across multiple computer-readable media, such that instructions may be executed by only one processor or by multiple processors in a distributed fashion, such that each apparatus of the one or more apparatuses may include one processor or multiple processors, and / or such that performance may be by only one apparatus or in a distributed fashion across multiple apparatuses); one or more computer program products embodied D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 4 on one or more computer-readable storage media comprising code for performing any portion of any method described herein (e.g., such that code may be stored in only one computer-readable medium or across computer-readable media in a distributed fashion); and / or one or more apparatuses comprising one or more means for performing any portion of any method described herein (e.g., such that performance would be by only one apparatus or by multiple apparatuses in a distributed fashion). By way of example, an apparatus may comprise a processing system, a device with a processing system, or processing systems cooperating over one or more networks. An apparatus may comprise one or more memories; and one or more processors configured to cause the apparatus to perform any portion of any method described herein. In some examples, one or more of the processors may be preconfigured to perform various functions or operations described herein without requiring configuration by software.

[0009] The following description and the appended figures set forth certain features for purposes of illustration. BRIEF DESCRIPTION OF DRAWINGS

[0010] The appended figures depict certain features of the various aspects described herein and are not to be considered limiting of the scope of this disclosure.

[0011] FIG. 1 depicts an example wireless communications network.

[0012] FIG. 2 depicts an example disaggregated base station architecture.

[0013] FIG. 3 depicts aspects of an example base station and an example user equipment (UE).

[0014] FIGS. 4A, 4B, 4C, and 4D depict various example aspects of data structures for a wireless communications network.

[0015] FIG. 5 depicts an example wireless communication device communicating with another device.

[0016] FIG. 6A depicts an example RF configuration of a device for wireless communications.

[0017] FIG. 6B depicts an example frequency offset for components of the example RF configuration.

[0018] FIG. 7 depicts an example illustration of transmission nonidealities. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 5

[0019] FIGS. 8A and 8B depict example flow diagrams for a calibration procedure.

[0020] FIG. 9 depicts an example averaging for a transmission nonideality.

[0021] FIG. 10 depicts a method for wireless communications.

[0022] FIG. 11 depicts aspects of an example communications device. DETAILED DESCRIPTION

[0023] Aspects of the present disclosure provide apparatuses, methods, processing systems, and computer-readable mediums for performing a calibration for a radio frequency (RF) circuit using variable sample averaging.

[0024] Certain wireless communications devices employ analog RF chain circuitry (e.g., mixers, filters, amplifiers, duplexers, diplexers, antenna tuners, etc.) to communicate via radio waves. In some cases, the RF chain circuitry may use multiple signal paths for modulation. For example, RF chain circuitry that performs quadrature modulation (e.g., quadrature phase-shift keying (QPSK) or quadrature amplitude modulation (QAM)) may have in-phase (I) and quadrature-phase (Q) signal paths. The in-phase / quadrature-phase (I / Q) signal paths may carry two signals that are in quadrature phase (e.g., a phase offset of one-quarter cycle, such as 90 degrees or π / 2 radians). For each of the I / Q signal paths, the RF chain circuitry may have a separate cascade of analog circuits (e.g., separate filters, mixers, amplifiers, etc.).

[0025] In some cases, modulation signal paths (e.g., I / Q signal paths) may impart different effects (e.g., different gain and / or phase offsets) on the respective signals, for example, due to filters and / or mixers in the modulation signal paths not being identical hardware components between the parallel signal paths. As a result, the phase difference between the I / Q components may not be exactly 90 degrees (or any other suitable phase offset between the parallel signal paths), and the gain of the I / Q components may not be perfectly matched between the parallel sections of circuitry dealing with the I / Q signal paths. For example, a transfer function of the in-phase signal pathmay not be equalto the transfer function of the quadrature signal path ^^dueto different mixers being used in each of the signal paths. Such an imbalance between the I / Q signal paths may be referred to as an I / Q imbalance. The I / Q imbalance can cause distortion (e.g., phase and gain errors) on communication signals. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 6

[0026] As an example with respect to distortion on a receive chain, the I / Q imbalance can cause residual sidebands (RSBs) (e.g., unwanted, remaining, or residual signals on one or more sideband frequencies outside the baseband frequency) to form in the digital baseband signal, which may affect the demodulation performance of the received signal. For example, RSB may be a transmission nonideality caused by a baseband mismatch (e.g., imbalance) in the I and Q signal paths. In some cases, the RSB nonideality may occur due to a mismatch in one of the following: mixer local oscillator (LO) phases deviating from a 90 degree ideality between the I and Q signal paths, a mismatch in baseband filter (BBF) poles between the I and Q signals, a mismatch in anti-aliasing filter (AAF) poles between the I and Q signals, and / or routing differences between the I and Q signal paths. For analog I / Q targets with RF and data converters on separate chips (e.g., separate RF circuits, separate RF circuit boards, etc.), each manufacturer (e.g., of the separate chips) may design the respective chips or circuit boards differently, such that each chip or circuit board may need to be calibrated separately for RSB correction. Additionally, to optimize cost, some manufacturers may not maintain a tight control on matching routing between the I and Q signal paths. Thus, correcting the RSB nonideality may be performed to maintain competitive uplink performance (e.g., for high modulations, such as 256QAM).

[0027] As the distortion may be specific to the hardware in the RF chain circuitry of a wireless communications device, the wireless communications device may perform distortion compensation. The distortion compensation may be determined through a device calibration process, for example, as a part of manufacturing the wireless communications device. During the calibration process, a calibration signal having one or more training tones (e.g., with known parameters) may be applied to the RF chain circuitry for the wireless communications device to measure the distortion caused by the RF chain circuitry. For example, signals that pass through the RF chain circuitry may be compared to the known calibration signal by the wireless communications device to identify how the signals that passed through the RF chain circuitry were distorted with respect to the known calibration signal. Subsequently, the wireless communications device may determine and use a digital filter to suppress the distortion encountered due to I / Q imbalance in the RF chain circuitry.

[0028] As an example, an N-tap finite impulse response (FIR) filter may be used by the wireless communications device to suppress the RSB distortion of a receive chain. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 7 Filter coefficients for the FIR filter may be determined by the wireless communications device during device calibration. The filter coefficients may be determined using a technique that minimizes the distortion (e.g., the RSB energy) at or caused by the training tones of the calibration signal in an operating bandwidth. The filter may be configured to have a particular number of taps, which may define the total number of coefficients and delays of an FIR filter. The filter coefficients may be stored in memory on the wireless communications device and used to suppress or cancel distortion in communication signals.

[0029] In some cases, such a calibration technique is performed in a non-trivial amount of time. For example, the filter coefficients may be determined for multiple operating scenarios, such as for each combination of bandwidth, analog to digital conversion (ADC) rate, and / or filtering mode (e.g., a half-band filtering mode, normal filtering mode, etc.). Each of the operating scenarios may take a certain amount of time to calibrate the distortion compensation.

[0030] In certain cases, the calibration technique may only be capable of minimizing the distortion encountered for the training tones of the calibration signal in each of the frequency bandwidths calibrated. Some of the filter coefficients may allow some distortion to pass at certain frequencies in a frequency bandwidth of a respective calibration signal due to the filter coefficients being configured to minimize the distortion at the training tones. Additionally or alternatively, some of the filter coefficients may allow some distortion caused by other frequencies in a frequency bandwidth of a respective calibration signal due to the filter coefficients being configured to minimize the distortion caused by the training tones. In other words, the training tones of a calibration signal may provide a partial characterization of the distortion encountered at a frequency bandwidth.

[0031] Additionally or alternatively, the distortion may be caused by a local oscillator (LO) signal used to feed an input signal to drive an RF mixer. For example, the LO signal may leak to an output of the RF mixer. In some cases, mixers may be designed to be double-balanced to cancel this LO leakage. However, some residual LO leakage may occur due to mismatches (e.g., I / Q mismatches and / or I / Q imbalances). In some cases, this type of LO leakage may be referenced as LO feedthrough (LOFT). D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 8

[0032] In some cases, the calibration techniques described above and herein may be performed on a transmit chain of an RF transceiver and on a receive chain of the RF transceiver to mitigate distortions caused by RF elements on each chain of the RF transceiver. For example, both the transmit chain and the receive chain may include respective RF elements (e.g., converters, filters, mixers, LOs, etc.) that can cause distortions to transmitted signals. Accordingly, the calibration techniques may estimate the effects of the distortions from the transmit chain and the receive chain (e.g., estimate respective RSB values, respective LOFT values, gain errors (GEs), phase errors (PEs), etc.) based on comparing communicated signals (e.g., signals sent through the transmit chain and / or signals received through the receive chain) to a calibration signal (e.g., with known parameters), such that filter parameters (e.g., filter coefficients, codes, etc.) may be determined to mitigate the estimated distortion effects. In some aspects, the distortions from the transmit chain may be considered frequency independent distortions, and the distortions from the receive chain may be considered frequency dependent distortions or vice versa or any combination of frequency independent and frequency dependent distortions.

[0033] To provide more accurate estimates of the distortion effects, the RF transceiver may include respective transmit phase-locked loops (PLLs) to provide respective LO signals to RF mixers of the transmit chain and the receive chain. For example, the RF transceiver may include a first transmit PLL that provides a first LO signal to a first RF mixer of the transmit chain and may include a second transmit PLL that provides a second LO signal to a second RF mixer of the receive chain. A PLL may generate an output signal whose phase is fixed relative to the phase of an input signal, where keeping the input and output phase in lockstep may also imply keeping the input and output frequencies the same. Thus, a PLL may also track an input frequency, and by incorporating a frequency divider, the PLL can generate a stable frequency that is a multiple of the input frequency. Accordingly, the stable frequency generated by the PLL for the LO signal and RF mixer may be leveraged to produce and / or identify a stable and more accurate estimate of the distortion effects with a lesser number of averages (e.g., less computational complexity) from the transmit chain and from the receive chain (e.g., the transmit PLLs have narrow phase noise profiles, leading to more accurate signal measurements and / or estimates). D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 9

[0034] In some cases, when an RF transceiver includes two transmit PLLs to feed respective LO signals to respective RF mixers of a transmit chain and a receive chain, the calibration techniques may include using both transmit PLLs for RSB calibration (and / or LOFT calibration). Based on the narrow phase noise profiles of the transmit PLLs, a number of averages to achieve a signal-to-noise ratio (SNR) threshold (or other signal quality measurement) may be determined relatively easily. For example, the number of averages may correspond to a number of digital samples to obtain from an output signal at the receive chain (e.g., a feedback receive chain) corresponding to a calibration signal (e.g., sent via the transmit chain), where the number of digital samples are averaged to determine average signal measurements of the output signal. Subsequently, the narrow phase noise profiles may correspond to less variability in signal measurements of the digital samples, such that the number of digital samples that need to be obtained for signal measurements that achieve the SNR threshold may be relatively easy to determine based on the reduced variability. That is, the transmit PLLs may have suitable and deterministic phase noise profiles that can be leveraged to achieve the SNR threshold.

[0035] Subsequently, the effects of the distortions on the calibration signal (e.g., which may be indicative of how the distortions would affect other communications) may be identified based on averaging the number of digital samples and determining an average noise value of the digital samples, where the average noise value may correspond to distortion measurements (e.g., RSB estimates, LOFT estimates, GE estimates, PE estimates, etc.) for the calibration techniques. Thus, the averaging of the digital samples may result in determining an average distortion measurement (e.g., a desired RSB target) that still achieves the SNR threshold, and filter parameters may be determined to mitigate the average distortion measurement for transmitted signals, where the filter parameters may then be applied to a filter for the transmitted signals.

[0036] In some cases, the calibration techniques may be performed at a factory (e.g., during production of the RF circuits and / or wireless communications devices that employ the RF circuits) to generate filters for mitigating expected distortions. For example, a factory calibration may be performed for distortion calibration using the two transmit PLLs, where a number of averages to achieve a desired SNR is fixed. Subsequently, if the post calibration measurements of a signal (e.g., that include the distortions, such as RSB and / or LOFT) are greater than a target SNR threshold (e.g., indicating the signal includes an acceptable signal quality), a distortion filter may be generated to mitigate the D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 10 distortions, and the distortion filter may be used for online applications of the RF circuits. In some aspects, online applications may include an apparatus (e.g., wireless communications device) that includes the RF circuits being in continuous or intermittent communication with a wireless network to connect a voice call, a data exchange, or a combination thereof. Alternatively, if the post calibration measurements are less than the target SNR threshold, a calibration failure may be determined, and the RF circuit may not be used for the online applications.

[0037] However, some RF circuits may include a single transmit PLL configured to provide an LO signal to an RF mixer of the transmit chain, resulting in one or more technical problems. For example, some devices may be limited by an available size for the RF circuits, such as wearable devices (e.g., smart watches), mobile broadband (MBB) devices, low tier devices, low cost devices, and other devices where reducing RF integrated circuits (RFICs) areas and reducing average unit cost (AuC) targets are critical benchmarks. To achieve reduced RFIC areas and reduced AuC targets, analog I / Q software-defined radios (SDRs) may be used for these types of devices, where the analog I / Q SDRs include a single transmit chain driven by a single transmit PLL. In some cases, for analog I / Q RF circuits, uncalibrated distortions (e.g., transmit RSB, LOFT, etc.) may be high values (e.g., about 25 decibels (dB) or worse relative to a power of a carrier signal, given by dB of a carrier (dBc)). As such, to maintain optimum uplink throughput performance even on devices that include the analog I / Q SDRs for higher modulations (e.g., 256QAM and 100 megahertz (MHz) bandwidths), it may be desired to minimize transmit nonidealities (e.g., the distortions, such as RSB and / or LOFT), such as by calibration. However, with the analog I / Q SDRs supporting or allowing the single transmit PLL for the transmit chain, another source for providing an LO signal to an RF mixer of the receive chain may be needed for the calibration.

[0038] Accordingly, apparatuses described herein may provide a technical solution for devices with analog I / Q SDRs to include a low-power mode (LPM) synthesizer, where the LPM synthesizer may include a lower cost and may occupy a smaller area on-chip than other types of synthesizers. Based on the absence of a second transmit PLL in devices with the analog I / Q SDRs, the LPM synthesizer may be configured to provide an LO signal to an RF mixer of the receive chain to perform the calibration described previously. For example, the LPM synthesizer may provide or support a low-intermediate frequency (LIF)-based calibration, where a frequency tone corresponding to the LPM synthesizer is D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 11 offset (e.g., based on an LIF offset) from a frequency tone corresponding to the single transmit PLL. Subsequently, the offset between the frequency tones may enable identification of the separate distortions caused by the RF elements of the receive chain (e.g., according to the frequency tone corresponding to the LPM synthesizer) and the RF elements of the transmit chain (e.g., according to the frequency tone corresponding to the single transmit PLL). In some aspects, the identification of the separate distortions may be used to then generate filter parameters for a suitable filter to mitigate the distortions. Additionally, the apparatuses described herein may include an internal loopback path and an external loopback path for selectively performing the calibration (e.g., based on the apparatus being in an online operation or an offline operation).

[0039] If a same LO frequency is used for both the transmit chain and the receive chain (e.g., based on using the single transmit PLL to provide respective LO signals to respective RF mixers of the transmit chain and the receive chain), signal measurements and corresponding distortion measurements for the transmit chain and for the receive chain may fall in a same spectral region and may be indistinguishable from each other. Additionally or alternatively, designing a special waveform and using digital signal processing techniques to distinguish between signal measurements and corresponding distortion measurements for the transmit chain and for the receive chain may be less suitable for the online applications based on the digital signal processing techniques being limited by an available timeline. For example, digital signal processing techniques may include high processing times to distinguish the different signal measurements and corresponding distortion measurements at the device, which may increase latency and / or result in incorrect measurements based on a limited amount of time to perform the digital signal processing.

[0040] Thus, the LPM synthesizer may provide a calibration procedure for RF transceivers with low AuC targets and a need to minimize on-chip areas, where the calibration procedure may also enable distinguishing between signal measurements and corresponding distortion measurements for the transmit chain and for the receive chain, respectively. However, in some aspects, the LPM synthesizer may include a poorer phase noise profile (e.g., poorer integrated phase noise (IPN)) compared to the transmit PLLs, which may result in a poorer SNR during the calibration for a given number of signal averages. For example, a phase noise profile of the LPM synthesizer may include a wider phase profile (e.g., a wider phase noise skirt) compared to a phase noise profile of the D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 12 transmit PLL. Statically increasing a number of averages to recover the SNR may involve prohibitive time and power penalties.

[0041] Accordingly, techniques and signaling are described herein for calibrations using an LPM synthesizer that enable dynamic updates to a number of averages for performing the calibration (e.g., dynamic averaging) to recover lost SNR due to a degraded phase noise of the LPM synthesizer. For example, the techniques and signaling may leverage one or more inputs to determine a number of averages to use for the calibration, where the one or more inputs include a desired uplink throughput of one or more communication signals, target distortion measurements (e.g., RSB, LOFT, etc.) to achieve the desired uplink throughput, an amount of time between scheduled uplink transmissions, a transmit power, one or more radio link metrics of the one or more communication signals, an internal temperature of a device utilizing the LPM synthesizer, a bandwidth or bandwidth part being used for the one or more communication signals, or a combination thereof. That is, the techniques and signaling may provide a methodology and framework to maximally reduce the impact of nonidealities (e.g., distortions) to maximize throughput for low tier devices and / or low cost devices (e.g., devices with smaller sized RF transceivers, with a single transmit PLL, with an LPM synthesizer, etc.), while actively and dynamically making trade-off choices with respect to calibration time and without impacting scheduled uplink instances and across temperature.

[0042] In some aspects, a device may opportunistically perform online transmission calibrations (e.g., while the device is in continuous or intermittent communication with a wireless network) between scheduled uplink transmissions. For example, the device may be configured for power saving features, where the power saving features may rely on early indications and predictable scheduling of traffic. In some aspects, the power saving features may include discontinuous reception (DRX), discontinuous transmission (DTX), paging early indicators (PEIs), wake-up signals (WUSs), cross-slot scheduling, radio resource management (RRM) measurement relaxation in idle or inactive modes, radio link monitoring (RLM) relaxation, etc. Such power saving features may then be leveraged strategically to identify dead time between uplink instances to optimize the calibration, filtering, and distortion compensation for the device. For example, the calibrations may leverage the time between active slots to implement an online calibration algorithm with dynamic averaging to maximize throughput under variable field conditions and across temperature. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 13

[0043] The techniques, signaling, and apparatuses for opportunistically performing online transmission calibration using an LPM synthesizer as described herein may provide any of various technical beneficial effects and / or advantages. For example, the LPM synthesizer may be used for SDRs and / or other devices that include low AuC targets, minimized on-chip areas, and a single transmit PLL, thereby making calibration and performance (e.g., by implication of the calibration) scalable to low tier and low power devices. In some aspects, dynamically changing a number of averages during online transmission calibrations (e.g., while employing the LPM synthesizer to drive the LO of the receive path) may help achieve a best tradeoff between calibration time and a desired transmission nonideality mitigation. For example, dynamically changing the number of averages may result in a better uplink throughput across temperature while still mitigating transmission nonideality and / or distortion issues (e.g., RSB, LOFT, LO folding, etc.).

[0044] In some aspects, the techniques and signaling described herein may avoid a dependence on longer calibration sequences (e.g., performed in a factory using expensive callboxes and / or spectrum analyzers). For example, using an internal loopback-based calibration for an RF circuit in a device may reduce calibration time as compared to performing calibrations for the RF circuit prior to deployment in the device (e.g., on the factory floor). In some aspects, the techniques and signaling described herein may include performing the calibrations while the device is online, allowing for distortion correction across temperature and usage environments. In some aspects, the online calibrations may be performed opportunistically (e.g., based on dead time available between active communication slots) with the number of averages being determined for the online calibrations being considered in timing calculations and traded off for online performance.

[0045] As such, the apparatuses, techniques, and signaling described herein for performing calibrations using an LPM synthesizer that enable dynamic updates to a number of averages for performing the calibration may support less complex RF designs (e.g., for low tier and low cost devices) while still mitigating expected distortions from RF elements, leading to more efficient communications. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 14 Introduction to Wireless Communications Networks

[0046] The techniques and methods described herein may be used for various wireless communications networks. While aspects may be described herein using terminology commonly associated with 3G, 4G, 5G, 6G, and / or other generations of wireless technologies, aspects of the present disclosure may likewise be applicable to other communications systems and standards not explicitly mentioned herein.

[0047] FIG. 1 depicts an example of a wireless communications network 100, in which aspects described herein may be implemented.

[0048] Generally, wireless communications network 100 includes various network entities (alternatively, network elements or network nodes). A network entity is generally a communications device and / or a communications function performed by a communications device (e.g., a user equipment (UE), a base station (BS), a component of a BS, a server, etc.). As such communications devices are part of wireless communications network 100, and facilitate wireless communications, such communications devices may be referred to as wireless communications devices. For example, various functions of a network as well as various devices associated with and interacting with a network may be considered network entities. Further, wireless communications network 100 includes terrestrial aspects (also referred to herein as non- terrestrial network entities), such as ground-based network entities (e.g., BSs 102), and non-terrestrial aspects, such as satellite 140 and / or aerial or spaceborne platform(s), which may include network entities on-board (e.g., one or more BSs) capable of communicating with other network elements (e.g., terrestrial BSs) and UEs.

[0049] In the depicted example, wireless communications network 100 includes BSs 102, UEs 104, and one or more core networks, such as an Evolved Packet Core (EPC) 160 and 5G Core (5GC) network 190, which interoperate to provide communications services over various communications links, including wired and wireless links.

[0050] FIG.1 depicts various example UEs 104, which may more generally include: a cellular phone, smart phone, session initiation protocol (SIP) phone, laptop, personal digital assistant (PDA), satellite radio, global positioning system, multimedia device, video device, digital audio player, camera, game console, tablet, smart device, wearable device, vehicle, electric meter, gas pump, large or small kitchen appliance, healthcare device, implant, sensor / actuator, display, internet of things (IoT) devices, always on D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 15 (AON) devices, edge processing devices, data centers, or other similar devices. UEs 104 may also be referred to more generally as a mobile device, a wireless device, a station, a mobile station, a subscriber station, a mobile subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a remote device, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, and others.

[0051] BSs 102 wirelessly communicate with (e.g., transmit signals to or receive signals from) UEs 104 via communications links 120. The communications links 120 between BSs 102 and UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a BS 102 and / or downlink (DL) (also referred to as forward link) transmissions from a BS 102 to a UE 104. The communications links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity in various aspects.

[0052] BSs 102 may generally include: a NodeB, enhanced NodeB (eNB), next generation enhanced NodeB (ng-eNB), next generation NodeB (gNB or gNodeB), access point, base transceiver station, radio base station, radio transceiver, transceiver function, transmission reception point, and / or others. Each of BSs 102 may provide communications coverage for a respective coverage area 110, which may sometimes be referred to as a cell, and which may overlap in some cases (e.g., small cell 102’ may have a coverage area 110’ that overlaps the coverage area 110 of a macro cell). A BS may, for example, provide communications coverage for a macro cell (covering relatively large geographic area), a pico cell (covering relatively smaller geographic area, such as a sports stadium), a femto cell (relatively smaller geographic area (e.g., a home)), and / or other types of cells.

[0053] Generally, a cell may refer to a portion, partition, or segment of wireless communication coverage served by a network entity within a wireless communication network. A cell may have geographic characteristics, such as a geographic coverage area, as well as radio frequency characteristics, such as time and / or frequency resources dedicated to the cell. For example, a specific geographic coverage area may be covered by multiple cells employing different frequency resources (e.g., bandwidth parts) and / or different time resources. As another example, a specific geographic coverage area may be covered by a single cell. In some contexts (e.g., a carrier aggregation scenario and / or multi-connectivity scenario), the terms “cell” or “serving cell” may refer to or correspond to a specific carrier frequency (e.g., a component carrier) used for wireless D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 16 communications, and a “cell group” may refer to or correspond to multiple carriers used for wireless communications. As examples, in a carrier aggregation scenario, a UE may communicate on multiple component carriers corresponding to multiple (serving) cells in the same cell group, and in a multi-connectivity (e.g., dual connectivity) scenario, a UE may communicate on multiple component carriers corresponding to multiple cell groups.

[0054] While BSs 102 are depicted in various aspects as unitary communications devices, BSs 102 may be implemented in various configurations. For example, one or more components of a base station may be disaggregated, including a central unit (CU), one or more distributed units (DUs), one or more radio units (RUs), a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC), or a Non-Real Time (Non-RT) RIC, to name a few examples. In another example, various aspects of a base station may be virtualized. More generally, a base station (e.g., BS 102) may include components that are located at a single physical location or components located at various physical locations. In examples in which a base station includes components that are located at various physical locations, the various components may each perform functions such that, collectively, the various components achieve functionality that is similar to a base station that is located at a single physical location. In some aspects, a base station including components that are located at various physical locations may be referred to as a disaggregated radio access network architecture, such as an Open RAN (O-RAN) or Virtualized RAN (VRAN) architecture. FIG. 2 depicts and describes an example disaggregated base station architecture.

[0055] Different BSs 102 within wireless communications network 100 may also be configured to support different radio access technologies, such as 3G, 4G, and / or 5G. For example, BSs 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E- UTRAN)) may interface with the EPC 160 through first backhaul links 132 (e.g., an S1 interface). BSs 102 configured for 5G (e.g., 5G NR or Next Generation RAN (NG-RAN)) may interface with 5GC 190 through second backhaul links 184. BSs 102 may communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over third backhaul links 134 (e.g., X2 interface), which may be wired or wireless.

[0056] Wireless communications network 100 may subdivide the electromagnetic spectrum into various classes, bands, channels, or other features. In some aspects, the subdivision is provided based on wavelength and frequency, where frequency may also D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 17 be referred to as a carrier, a subcarrier, a frequency channel, a tone, or a subband. For example, 3GPP currently defines Frequency Range 1 (FR1) as including 410 MHz – 7125 MHz, which is often referred to (interchangeably) as “Sub-6 GHz”. Similarly, 3GPP currently defines Frequency Range 2 (FR2) as including 24,250 MHz – 71,000 MHz, which is sometimes referred to (interchangeably) as a “millimeter wave” (“mmW” or “mmWave”). In some cases, FR2 may be further defined in terms of sub-ranges, such as a first sub-range FR2-1 including 24,250 MHz – 52,600 MHz and a second sub-range FR2-2 including 52,600 MHz – 71,000 MHz. A base station configured to communicate using mmWave / near mmWave radio frequency bands (e.g., a mmWave base station such as BS 180) may utilize beamforming (e.g., 182) with a UE (e.g., 104) to improve path loss and range.

[0057] The communications links 120 between BSs 102 and, for example, UEs 104, may be through one or more carriers, which may have different bandwidths (e.g., 5, 10, 15, 20, 100, 400, and / or other MHz), and which may be aggregated in various aspects. Carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL).

[0058] Communications using higher frequency bands may have higher path loss and a shorter range compared to lower frequency communications. Accordingly, certain base stations (e.g., 180 in FIG. 1) may utilize beamforming 182 with a UE 104 to improve path loss and range. For example, BS 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and / or antenna arrays to facilitate the beamforming. In some cases, BS 180 may transmit a beamformed signal to UE 104 in one or more transmit directions 182’. UE 104 may receive the beamformed signal from the BS 180 in one or more receive directions 182’’. UE 104 may also transmit a beamformed signal to the BS 180 in one or more transmit directions 182’’. BS 180 may also receive the beamformed signal from UE 104 in one or more receive directions 182’. BS 180 and UE 104 may then perform beam training to determine the best receive and transmit directions for each of BS 180 and UE 104. Notably, the transmit and receive directions for BS 180 may or may not be the same. Similarly, the transmit and receive directions for UE 104 may or may not be the same. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 18

[0059] Wireless communications network 100 further includes a Wi-Fi AP 150 in communication with Wi-Fi stations (STAs) 152 via communications links 154 in, for example, a 2.4 GHz and / or 5 GHz unlicensed frequency spectrum.

[0060] Certain UEs 104 may communicate with each other using device-to-device (D2D) communications link 158. D2D communications link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), and / or a physical sidelink feedback channel (PSFCH).

[0061] EPC 160 may include various functional components, including: a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and / or a Packet Data Network (PDN) Gateway 172, such as in the depicted example. MME 162 may be in communication with a Home Subscriber Server (HSS) 174. MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, MME 162 provides bearer and connection management.

[0062] Generally, user Internet protocol (IP) packets are transferred through Serving Gateway 166, which itself is connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation as well as other functions. PDN Gateway 172 and the BM-SC 170 are connected to IP Services 176, which may include, for example, the Internet, an intranet, an IP Multimedia Subsystem (IMS), a Packet Switched (PS) streaming service, and / or other IP services.

[0063] BM-SC 170 may provide functions for MBMS user service provisioning and delivery. BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN), and / or may be used to schedule MBMS transmissions. MBMS Gateway 168 may be used to distribute MBMS traffic to the BSs 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and / or may be responsible for session management (start / stop) and for collecting eMBMS related charging information.

[0064] 5GC 190 may include various functional components, including: an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 19 Function (SMF) 194, and a User Plane Function (UPF) 195. AMF 192 may be in communication with Unified Data Management (UDM) 196.

[0065] AMF 192 is a control node that processes signaling between UEs 104 and 5GC 190. AMF 192 provides, for example, quality of service (QoS) flow and session management.

[0066] Internet protocol (IP) packets are transferred through UPF 195, which is connected to the IP Services 197, and which provides UE IP address allocation as well as other functions for 5GC 190. IP Services 197 may include, for example, the Internet, an intranet, an IMS, a PS streaming service, and / or other IP services.

[0067] In various aspects, a network entity or network node can be implemented as an aggregated base station, as a disaggregated base station, a component of a base station, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, to name a few examples.

[0068] UE 104 includes a calibration component 198, which may be used to perform calibrations using an LPM synthesizer (e.g., for an RF circuit of the UE 104) with dynamic updates to a number of averages for performing the calibration as further described herein.

[0069] FIG. 2 depicts an example disaggregated base station 200 architecture. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that can communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 225 via an E2 link, or a Non-Real Time (Non-RT) RIC 215 associated with a Service Management and Orchestration (SMO) Framework 205, or both). A CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an F1 interface. The DUs 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RUs 240 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, the UE 104 may be simultaneously served by multiple RUs 240.

[0070] Each of the units, e.g., the CUs 210, the DUs 230, the RUs 240, as well as the Near-RT RICs 225, the Non-RT RICs 215 and the SMO Framework 205, may include one or more interfaces or be coupled to one or more interfaces configured to receive or D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 20 transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communications interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or transmit signals over a wired transmission medium to one or more of the other units. Additionally or alternatively, the units can include a wireless interface, which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver), configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.

[0071] In some aspects, the CU 210 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 210. The CU 210 may be configured to handle user plane functionality (e.g., Central Unit – User Plane (CU-UP)), control plane functionality (e.g., Central Unit – Control Plane (CU-CP)), or a combination thereof. In some implementations, the CU 210 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as the E1 interface when implemented in an O-RAN configuration. The CU 210 can be implemented to communicate with the DU 230, as necessary, for network control and signaling.

[0072] The DU 230 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 240. In some aspects, the DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, or the like) depending, at least in part, on a functional split, such as those defined by the 3rdGeneration Partnership Project (3GPP). In some aspects, the DU 230 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 230, or with the control functions hosted by the CU 210. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 21

[0073] Lower-layer functionality can be implemented by one or more RUs 240. In some deployments, an RU 240, controlled by a DU 230, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like), or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU(s) 240 can be implemented to handle over the air (OTA) communications with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control and user plane communications with the RU(s) 240 can be controlled by the corresponding DU 230. In some scenarios, this configuration can enable the DU(s) 230 and the CU 210 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

[0074] The SMO Framework 205 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO Framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements can include, but are not limited to, CUs 210, DUs 230, RUs 240 and Near-RT RICs 225. In some implementations, the SMO Framework 205 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 211, via an O1 interface. Additionally, in some implementations, the SMO Framework 205 can communicate directly with one or more DUs 230 and / or one or more RUs 240 via an O1 interface. The SMO Framework 205 also may include a Non-RT RIC 215 configured to support functionality of the SMO Framework 205.

[0075] The Non-RT RIC 215 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence / Machine Learning (AI / ML) workflows including model training and updates, or policy-based guidance of applications / features in the Near-RT RIC 225. The Non-RT RIC 215 may be coupled to or communicate with (such as via an A1 interface) D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 22 the Near-RT RIC 225. The Near-RT RIC 225 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 210, one or more DUs 230, or both, as well as an O-eNB, with the Near-RT RIC 225.

[0076] In some implementations, to generate AI / ML models to be deployed in the Near-RT RIC 225, the Non-RT RIC 215 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 225 and may be received at the SMO Framework 205 or the Non-RT RIC 215 from non- network data sources or from network functions. In some examples, the Non-RT RIC 215 or the Near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 215 may monitor long-term trends and patterns for performance and employ AI / ML models to perform corrective actions through the SMO Framework 205 (such as reconfiguration via O1) or via creation of RAN management policies (such as A1 policies).

[0077] FIG. 3 depicts aspects of an example BS 102 and a UE 104.

[0078] Generally, BS 102 includes various processors (e.g., 318, 320, 330, 338, and 340), antennas 334a-t (collectively 334), transceivers 332a-t (collectively 332), which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., data source 312) and wireless reception of data (e.g., data sink 314). For example, BS 102 may send and receive data between BS 102 and UE 104. BS 102 includes controller / processor 340, which may be configured to implement various functions described herein related to wireless communications. Note that the BS 102 may have a disaggregated architecture as described herein with respect to FIG. 2.

[0079] Generally, UE 104 includes various processors (e.g., 358, 364, 366, 370, and 380), antennas 352a-r (collectively 352), transceivers 354a-r (collectively 354), which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., retrieved from data source 362) and wireless reception of data (e.g., provided to data sink 360). UE 104 includes controller / processor 380, which may be configured to implement various functions described herein related to wireless communications. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 23

[0080] In regards to an example downlink transmission, BS 102 includes a transmit processor 320 that may receive data from a data source 312 and control information from a controller / processor 340. The control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid automatic repeat request (HARQ) indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), and / or others. The data may be for the physical downlink shared channel (PDSCH), in some examples.

[0081] Transmit processor 320 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Transmit processor 320 may also generate reference symbols, such as for the primary synchronization signal (PSS), secondary synchronization signal (SSS), PBCH demodulation reference signal (DMRS), and channel state information reference signal (CSI-RS).

[0082] Transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and / or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) in transceivers 332a-332t. Each modulator in transceivers 332a- 332t may process a respective output symbol stream to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from the modulators in transceivers 332a-332t may be transmitted via the antennas 334a-334t, respectively.

[0083] In order to receive the downlink transmission, UE 104 includes antennas 352a- 352r that may receive the downlink signals from the BS 102 and may provide received signals to the demodulators (DEMODs) in transceivers 354a-354r, respectively. Each demodulator in transceivers 354a-354r may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples to obtain received symbols.

[0084] A receive (RX) MIMO detector 356 may obtain received symbols from all the demodulators in transceivers 354a-354r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. Receive processor 358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 24 for the UE 104 to a data sink 360, and provide decoded control information to a controller / processor 380.

[0085] In regards to an example uplink transmission, UE 104 further includes a transmit processor 364 that may receive and process data (e.g., for the physical uplink shared channel (PUSCH)) from a data source 362 and control information (e.g., for the physical uplink control channel (PUCCH)) from the controller / processor 380. Transmit processor 364 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS)). The symbols from the transmit processor 364 may be precoded by a TX MIMO processor 366 if applicable, further processed by the modulators in transceivers 354a-354r (e.g., for single-carrier frequency division multiplexing (SC- FDM)), and transmitted to BS 102.

[0086] At BS 102, the uplink signals from UE 104 may be received by antennas 334a- t, processed by the demodulators in transceivers 332a-332t, detected by a RX MIMO detector 336 if applicable, and further processed by a receive processor 338 to obtain decoded data and control information sent by UE 104. Receive processor 338 may provide the decoded data to a data sink 314 and the decoded control information to the controller / processor 340.

[0087] Memories 342 and 382 may store data and program codes for BS 102 and UE 104, respectively.

[0088] Scheduler 344 may schedule UEs for data transmission on the downlink and / or uplink.

[0089] In various aspects, BS 102 may be described as transmitting and receiving various types of data associated with the methods described herein. In these contexts, “transmitting” may refer to various mechanisms of outputting data, such as outputting data from data source 312, scheduler 344, memory 342, transmit processor 320, controller / processor 340, TX MIMO processor 330, transceivers 332a-t, antenna 334a-t, and / or other aspects described herein. Similarly, “receiving” may refer to various mechanisms of obtaining data, such as obtaining data from antennas 334a-t, transceivers 332a-t, RX MIMO detector 336, controller / processor 340, receive processor 338, scheduler 344, memory 342, and / or other aspects described herein.

[0090] In various aspects, UE 104 may likewise be described as transmitting and receiving various types of data associated with the methods described herein. In these D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 25 contexts, “transmitting” may refer to various mechanisms of outputting data, such as outputting data from data source 362, memory 382, transmit processor 364, controller / processor 380, TX MIMO processor 366, transceivers 354a-t, antenna 352a-t, and / or other aspects described herein. Similarly, “receiving” may refer to various mechanisms of obtaining data, such as obtaining data from antennas 352a-t, transceivers 354a-t, RX MIMO detector 356, controller / processor 380, receive processor 358, memory 382, and / or other aspects described herein.

[0091] In some aspects, a processor may be configured to perform various operations, such as those associated with the methods described herein, and transmit (output) to or receive (obtain) data from another interface that is configured to transmit or receive, respectively, the data.

[0092] In various aspects, artificial intelligence (AI) processors 318 and 370 may perform AI processing for BS 102 and / or UE 104, respectively. The AI processor 318 may include AI accelerator hardware or circuitry such as one or more neural processing units (NPUs), one or more neural network processors, one or more tensor processors, one or more deep learning processors, etc. The AI processor 370 may likewise include AI accelerator hardware or circuitry. As an example, the AI processor 370 may perform AI- based beam management, AI-based channel state feedback (CSF), AI-based antenna tuning, and / or AI-based positioning (e.g., non-line of sight positioning prediction). In some cases, the AI processor 318 may process feedback from the UE 104 (e.g., CSF) using hardware accelerated AI inferences and / or AI training. The AI processor 318 may decode compressed CSF from the UE 104, for example, using a hardware accelerated AI inference associated with the CSF. In certain cases, the AI processor 318 may perform certain RAN-based functions including, for example, network planning, network performance management, energy-efficient network operations, etc.

[0093] In the depicted example, controller / processor 380 includes a calibration component 381, which may be representative of the calibration component 198 of FIG. 1. Notably, while depicted as an aspect of controller / processor 380, the calibration component 381 may be implemented additionally or alternatively in various other aspects of UE 104 in other implementations.

[0094] FIGS. 4A, 4B, 4C, and 4D depict aspects of data structures for a wireless communications network, such as wireless communications network 100 of FIG. 1. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 26

[0095] In particular, FIG. 4A is a diagram 400 illustrating an example of a first subframe within a 5G (e.g., 5G NR) frame structure, FIG.4B is a diagram 430 illustrating an example of DL channels within a 5G subframe, FIG. 4C is a diagram 450 illustrating an example of a second subframe within a 5G frame structure, and FIG. 4D is a diagram 480 illustrating an example of UL channels within a 5G subframe.

[0096] Wireless communications systems may utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the uplink and downlink. Such systems may also support half-duplex operation using time division duplexing (TDD). OFDM and SC-FDM partition the system bandwidth (e.g., as depicted in FIGS. 4B and 4D) into multiple orthogonal subcarriers. Each subcarrier may be modulated with data. Modulation symbols may be sent in the frequency domain with OFDM and / or in the time domain with SC-FDM.

[0097] A wireless communications frame structure may be frequency division duplex (FDD), in which, for a particular set of subcarriers, subframes within the set of subcarriers are dedicated for either DL or UL. Wireless communications frame structures may also be time division duplex (TDD), in which, for a particular set of subcarriers, subframes within the set of subcarriers are dedicated for both DL and UL.

[0098] In FIG. 4A and 4C, the wireless communications frame structure is TDD where D is DL, U is UL, and X is flexible for use between DL / UL. UEs may be configured with a slot format through a received slot format indicator (SFI) (dynamically through DL control information (DCI), or semi-statically / statically through RRC signaling). In the depicted examples, a 10 ms frame is divided into 10 equally sized 1 ms subframes. Each subframe may include one or more time slots. In some examples, each slot may include 12 or 14 symbols, depending on the cyclic prefix (CP) type (e.g., 12 symbols per slot for an extended CP or 14 symbols per slot for a normal CP). Subframes may also include mini-slots, which generally have fewer symbols than an entire slot. Other wireless communications technologies may have a different frame structure and / or different channels.

[0099] In certain aspects, the number of slots within a subframe (e.g., a slot duration in a subframe) is based on a numerology, which may define a frequency domain subcarrier spacing and symbol duration as further described herein. In certain aspects, given a numerology µ, there are 2µslots per subframe. Thus, numerologies (µ) 0 to 6 may D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 27 allow for 1, 2, 4, 8, 16, 32, and 64 slots, respectively, per subframe. In some cases, the extended CP (e.g., 12 symbols per slot) may be used with a specific numerology, e.g., numerology 2 allowing for 4 slots per subframe. The subcarrier spacing and symbol length / duration are a function of the numerology. The subcarrier spacing may be equal to2^ × 15 kHz, where μ is the numerology 0 to 6. As an example, the numerology µ = 0corresponds to a subcarrier spacing of 15 kHz, and the numerology µ = 6 corresponds toa subcarrier spacing of 960 kHz. The symbol length / duration is inversely related to the subcarrier spacing. FIGS.4A, 4B, 4C, and 4D provide an example of a slot format having14 symbols per slot (e.g., a normal CP) and a numerology µ = 2 with 4 slots persubframe. In such a case, the slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

[0100] As depicted in FIGS. 4A, 4B, 4C, and 4D, a resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs)) that extends, for example, 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme including, for example, quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM).

[0101] As illustrated in FIG.4A, some of the REs carry reference (pilot) signals (RS) for a UE (e.g., UE 104 of FIGS.1 and 3). The RS may include demodulation RS (DMRS) and / or channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and / or phase tracking RS (PT-RS).

[0102] FIG. 4B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE including, for example, nine RE groups (REGs), each REG including, for example, four consecutive REs in an OFDM symbol.

[0103] A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE (e.g., 104 of FIGS. 1 and 3) to determine subframe / symbol timing and a physical layer identity.

[0104] A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 28

[0105] Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI). Based on the PCI, the UE can determine the locations of the aforementioned DMRS. The physical broadcast channel (PBCH), which carries a master information block (MIB), may be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (SSB), and in some cases, referred to as a synchronization signal block (SSB). The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs), and / or paging messages.

[0106] As illustrated in FIG. 4C, some of the REs carry DMRS (indicated as R for one particular configuration, but other DMRS configurations are possible) for channel estimation at the base station. The UE may transmit DMRS for the PUCCH and DMRS for the PUSCH. The PUSCH DMRS may be transmitted, for example, in the first one or two symbols of the PUSCH. The PUCCH DMRS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. UE 104 may transmit sounding reference signals (SRS). The SRS may be transmitted, for example, in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0107] FIG. 4D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and HARQ acknowledgment (ACK) / negative acknowledgment (NACK) feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI. Aspects Related to RF Circuits

[0108] FIG. 5 depicts an example first device 504A (e.g., wireless communication device) communicating with a second device 504B. In some aspects, the first device 504A and the second device 504B may represent a UE 104 as described with reference to FIGS. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 29 1 and 3. Additionally or alternatively, the first device 504A may represent a UE 104 as described with reference to FIGS. 1 and 3, and the second device 504B may represent a BS 102 as described with reference to FIGS. 1 and 3.

[0109] The first device 504A may be, or may include, a chip, system on chip (SoC), system in package (SiP), chipset, package, device that includes one or more modems 510 (hereinafter “the modem 510”). In some cases, the modem 510 may include, for example, any of a wireless wide area network (WWAN) modem (e.g., a modem configured to communicate via E-UTRA 5G NR, and / or any future WWAN communications standards), a WLAN modem (e.g., a modem configured to communicate via IEEE 802.11 standards), a Bluetooth modem, a non-terrestrial network (NTN) modem, etc. In certain aspects, the first device 504A also includes one or more RF transceivers (hereinafter “the RF transceiver 550”). In some cases, the RF transceiver 550 may be referred to as an RF front end (RFFE). In some aspects, the modem 510 further includes one or more processors, processing blocks or processing elements (hereinafter “the processor 512”) and one or more memory blocks or elements (hereinafter “the memory 514”). In certain aspects, the processor 512 and / or the memory 514 are implemented external or otherwise separate from the modem 510.

[0110] In certain aspects, the processor 512 may process any of certain protocol stack layers associated with a RAT. For example, the processor 512 may process any of an application layer, packet layer, WLAN protocol stack layers (e.g., a link or a MAC layer), and / or WWAN protocol stack layers (e.g., a RRC layer, a PDCP layer, a RLC layer, and a MAC layer).

[0111] The modem 510 may generally be configured to implement a PHY layer. For example, the modem 510 may be configured to modulate packets and to output the modulated packets to the RF transceiver 550 for transmission over a wireless medium. The modem 510 is similarly configured to obtain modulated packets received by the RF transceiver 550 and to demodulate the packets to provide demodulated packets. In addition to a modulator and a demodulator, the modem 510 may further include digital signal processor (DSP) circuitry, an automatic gain control (AGC), a coder, a decoder, a multiplexer, and / or a demultiplexer (not shown).

[0112] As an example, while in a transmission mode, the modem 510 may obtain data from a data source, such as an application processor. The data may be provided to a coder, D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 30 which encodes the data to provide encoded bits. The encoded bits may be mapped to points in a modulation constellation (e.g., using a selected modulation and coding scheme) to provide modulated symbols. The modulated symbols may be mapped, for example, to spatial stream(s) or space-time streams. The modulated symbols may be multiplexed, transformed via an iFFT block, and subsequently provided to DSP circuitry for transmit windowing and filtering. The digital signals may be provided to a digital-to- analog converter (DAC) 516. In certain aspects involving beamforming, the modulated symbols in the respective spatial streams may be precoded via a steering matrix prior to provision to the iFFT block.

[0113] The modem 510 may be coupled to the RF transceiver 550 by a transmit (TX) path 518 (also known as a transmit chain) for transmitting signals via one or more antennas 520 (hereinafter “the antennas 520”) and a receive (RX) path 522 (also known as a receive chain) for receiving signals via the antennas 520. When the TX path 518 and the RX path 522 share the antennas 520, the paths may be coupled to the antennas 520 via an interface 524, which may include any of various suitable RF devices, such as an antenna tuner, a switch, a duplexer, a diplexer, a multiplexer, and the like. As an example, the modem 510 may output digital in-phase (I) and / or quadrature (Q) baseband signals representative of the respective symbols to the DAC 516. In some examples, all or most of the elements illustrated as being included in the RF transceiver 550 are implemented in a single chip or die. For example, in some configurations, all of the elements of the RF transceiver 550 except the antennas 520 are implemented on a single chip. In some other configurations, the interface 524 or a portion thereof is also omitted from the single chip.

[0114] Receiving I or Q baseband analog signals from the DAC 516, the TX path 518 may include a baseband filter (BBF) 526, a mixer 528 (which may include one or several mixers), and a power amplifier (PA) 530. The BBF 526 filters the baseband signals received from the DAC 516, and the mixer 528 mixes the filtered baseband signals with a transmit local oscillator (LO) signal to convert the baseband signal to a different frequency (e.g., upconvert from baseband to a radio frequency). In some aspects, the frequency conversion process produces the sum and difference frequencies between the LO frequency and the frequencies of the baseband signal. The sum and difference frequencies are referred to as the beat frequencies. Some beat frequencies are in the RF range, such that the signals output by the mixer 528 are typically RF signals, which may be amplified by the PA 530 before transmission by the antennas 520. The antennas 520 D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 31 may emit RF signals, which may be received at the second device 504B. While one mixer 528 is illustrated, several mixers may be used to upconvert the filtered baseband signals to one or more intermediate frequencies and to thereafter upconvert the intermediate frequency signals to a frequency for transmission.

[0115] The RX path 522 may include a low noise amplifier (LNA) 532, a mixer 534 (which may include one or several mixers), and a BBF 536. RF signals received via the antennas 520 (e.g., from the second device 504B) may be amplified by the LNA 532, and the mixer 534 mixes the amplified RF signals with a receive LO signal to convert the RF signals to a baseband frequency (e.g., downconvert). The baseband signals output by the mixer 534 may be filtered by the BBF 536 before being converted by an analog-to-digital converter (ADC) 538 to digital I or Q signals for digital signal processing. The modem 510 may receive the digital I or Q signals and may further process the digital signals, such as demodulating the digital signals into information.

[0116] Certain transceivers may employ frequency synthesizers with a voltage- controlled oscillator (VCO) to generate a stable, tunable LO frequency with a particular tuning range. Thus, the transmit LO frequency may be produced by a first frequency synthesizer 540A, which may be buffered or amplified by an amplifier (not shown) before being mixed with the baseband signals in the mixer 528. Similarly, the receive LO frequency may be produced by a second frequency synthesizer 540B, which may be buffered or amplified by an amplifier (not shown) before being mixed with the RF signals in the mixer 534. Separate frequency synthesizers may be used for the TX path 518 (e.g., the first frequency synthesizer 540A) and the RX path 522 (e.g., the second frequency synthesizer 540B). Alternatively, a same frequency synthesizer may be used for both the TX path 518 and the RX path 522 (e.g., the first frequency synthesizer 540A and the second frequency synthesizer 540B are a same frequency synthesizer).

[0117] While in a reception mode, the modem 510 may obtain digitally converted signals via the ADC 538 and RX path 522. As an example, in the modem 510, digital signals may be provided to the DSP circuitry, which is configured to acquire a received signal, for example, by detecting the presence of the signal and estimating the initial timing and frequency offsets. The DSP circuitry is further configured to digitally condition the digital signals, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correcting for I / Q imbalance), and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuitry may be fed to D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 32 the AGC, which is configured to use information extracted from the digital signals, for example, in one or more received training fields, to determine an appropriate gain. The output of the DSP circuitry also may be coupled with the demodulator, which is configured to extract modulated symbols from the signal and, for example, compute the logarithm likelihood ratios (LLRs) for each bit position of each subcarrier in each spatial stream. The demodulator may be coupled with the decoder, which may be configured to process the LLRs to provide decoded bits. The decoded bits from all of the spatial streams may be fed to the demultiplexer for demultiplexing. The demultiplexed bits may be descrambled and provided to a MAC layer (e.g., the processor 512) for processing, evaluation, or interpretation.

[0118] The modem 510 and / or processor 512 may control the transmission of signals via the TX path 518 and / or reception of signals via the RX path 522. In some aspects, the modem 510 and / or processor 512 may be configured to perform various operations, such as those associated with any of the methods described herein. The modem 510 and / or processor 512 may include a microcontroller, a microprocessor, an application processor, a baseband processor, a MAC processor, an AI processor, a DSP, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof. The memory 514 may store data and program codes (e.g., processor-readable instructions) for performing wireless communications as described herein. In some cases, the memory 514 may be external to the modem 510 and / or processor 512 and / or incorporated therein (as illustrated or with the memory 514 being incorporated with the processor 512).

[0119] FIG. 5 shows an example transceiver design. It will be appreciated that other transceiver designs or architectures may be applied in connection with aspects of the present disclosure. For example, while examples discussed herein utilize I and Q signals (e.g., quadrature modulation), those of skill in the art will understand that components of the transceiver may be configured to utilize any other suitable modulation, such as polar modulation. As another example, circuit blocks may be arranged differently from the configuration shown in FIG. 5, and / or other circuit blocks not shown in FIG. 5 may be implemented in addition to or instead of the blocks depicted. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 33 Aspects Related to an Example RF Circuit for Performing Calibrations

[0120] FIG. 6A depicts an example RF configuration 600 of a device for wireless communications in accordance with aspects of the present disclosure. In some aspects, the RF configuration 600 may implement aspects of or may be implemented by aspects of FIGS. 1–5. For example, the RF configuration 600 may be included in a device that corresponds to a UE or similar terminal device as described with reference to FIGS. 1 and 3 (e.g., UE 104,).

[0121] Additionally, the RF configuration 600 may include and / or represent aspects of FIG. 5. For example, the RF configuration 600 may include one or more processors 602 (e.g., which may represent the processor 512 as described with reference to FIG. 5), a TX path 604 (e.g., which may represent the TX path 518 as described with reference to FIG. 5), and a feedback RX path 606 (e.g., which may represent the RX path 522 as described with reference to FIG. 5). In some aspects, the TX path 518 may include a digital baseband (e.g., I and Q signals), a DAC (e.g., including a first DAC component, DAC_S1, for upconverting the I signal and a second DAC component, DAC_S2 for upconverting the Q signal), one or more BBFs, one or more first mixers 608, and a driver amplifier (DA) 618, which may represent respective elements and / or components of the TX path 518 as described with reference to FIG. 5. Additionally, the feedback RX path 606 may include an ADC (e.g., including a first ADC component, ADC_I, for downconverting the I signal and a second ADC component, ADC_Q, for downconverting the Q signal), one or more BBFs, one or more second mixers 612, and one or more LNAs 620, which may represent respective elements and / or components of the RX path 522 as described with reference to FIG. 5. In some aspects, the feedback RX path 606 may be selectively coupled to the TX path 604.

[0122] As described herein, the TX path 604 may include a first frequency synthesizer 610 that is configured to feed a first LO signal to the one or more first mixers 608, and the feedback RX path 606 may include a second frequency synthesizer 614 that is configured to feed a second LO signal to the one or more second mixers 612. In some aspects, the first frequency synthesizer 610 and first LO signal may be referenced as or may include a high-power mode (HPM) synthesizer or high-performance synthesizer, and the second frequency synthesizer 614 and second LO signal may be referenced as or may include a LPM synthesizer or low-performance synthesizer. In some aspects, the terms high-performance and low-performance may describe relative qualities of the D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 34 synthesizers relative to one another. For example, the high-performance synthesizer may include a better phase noise performance than the low-performance synthesizer. Additionally, the high-performance synthesizer may consume more power than the low- performance synthesizer. For example, the first frequency synthesizer 610 may be configured to consume a first amount of power, and the second frequency synthesizer 614 may be configured to consume a second amount of power that is less than first amount of power. Additionally, the high-performance synthesizer may occupy more chip real estate than the low-performance synthesizer. In some aspects, the low-performance synthesizer may also cost less to manufacture and / or to include on a chip compared to the high- performance synthesizer and / or other types of synthesizers.

[0123] For example, as shown in the example of FIG. 6B, a comparison 601 is depicted to illustrate the differences in the first LO signal (e.g., fed by the first frequency synthesizer 610 to the one or more first mixers 608) and the second LO signal (e.g., fed by the second frequency synthesizer 614 to the one or more second mixers 612). As shown in the example of FIG. 6B, the first LO signal may include a first frequency tone 642 with a first phase noise profile 648, and the second LO signal may include a second frequency tone 644 with a second phase noise profile 650. In some aspects, the second frequency tone 644 may be offset from the first frequency tone 642 by an offset 646, where the offset 646 may represent a LIF offset. Additionally, the second phase noise profile 650 may include a wider phase noise profile (e.g., wider phase noise skirt) than the first phase noise profile 648.

[0124] In some aspects, the offset 646 and the difference in phase noise profiles may be a result of using the first frequency synthesizer 610 for the one or more first mixers 608 and using the second frequency synthesizer 614 for the one or more second mixers 612. For example, the first frequency synthesizer 610 may represent an HPM synthesizer and / or high-performance synthesizer, such as a transmit PLL (e.g., as described previously), that has a narrow phase noise skirt for the first phase noise profile 648. Additionally or alternatively, the second frequency synthesizer 614 may represent an LPM synthesizer (e.g., as described previously) and / or low-performance synthesizer that includes a poorer phase noise profile (e.g., poorer IPN) compared to the transmit PLLs, such as a wider phase noise skirt for the second phase noise profile 650.

[0125] In some aspects, the RF configuration 600 may include a loopback path coupled between the TX path 604 and the feedback RX path 606, where the loopback D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 35 path includes one or more switches. For example, the loopback path may include an internal loopback path 616 (e.g., a loopback path that includes internal components of an RFIC). In some aspects, the internal loopback path 616 may include the DA 618; the one or more LNAs 620; and a first switch 622 that, when closed, couples the DA 618 to the one or more LNAs 620. In some aspects, the internal loopback path 616 may also include one or more mixers (e.g., the one or more first mixers 608 and the one or more second mixers 612), BBFs, DACs, and ADCs.

[0126] Additionally or alternatively, the loopback path may include an external loopback path 624 (e.g., a loopback path that includes the internal components of an RFIC and components external to the RFIC). In some aspects, the external loopback path 624 may include the DA 618; one or more PAs 626; the one or more LNAs 620; one or more antenna elements 628 (e.g., an antenna interface, such as the interface 524, and one or more antennas, such as the antennas 520 as described with reference to FIG.5); a second switch 630 that, when closed, couples the DA 618 to the one or more PAs 626; and a third switch 632 that, when closed, couples: the one or more PAs 626, the one or more antenna elements 628, and the one or more LNAs 620. In some aspects, the external loopback path 624 may also include one or more mixers (e.g., the one or more first mixers 608 and the one or more second mixers 612), BBFs, DACs, and ADCs.

[0127] In some aspects, when configured to use the external loopback path 624, the RF configuration 600 may include the first switch 622 being open and the second switch 630 and the third switch 632 being closed. Additionally or alternatively, when configured to use the internal loopback path 616, the RF configuration 600 may include the first switch 622 being closed and the second switch 630 and the third switch 632 being open.

[0128] As described herein, the RF configuration 600 may be used and / or implemented in a device to perform a calibration procedure for mitigating distortions caused by modulation signal paths (e.g., I / Q signal paths) imparting different effects (e.g., gain and / or phase offsets) on the respective signals, for example, due to filters and / or mixers in the signal paths not being identical hardware components between the parallel signal paths. For example, the distortions may include RSBs (e.g., a transmission nonideality caused by a baseband mismatch and / or imbalance in the I and Q signal paths) and / or LOFTs (e.g., residual LO leakage that occurs due to mismatches, such as I / Q mismatches and / or I / Q imbalance) as described previously. RSBs and LOFTs are described in greater detail with reference to FIG. 7. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 36

[0129] The calibration procedure may include performing a number of averages on one or more output signals received via the feedback RX path 606, where the number of averages correspond to a number of digital samples obtained from the one or more output signals. For example, the calibration procedure may estimate the effects of the distortions from the TX path 604 and the feedback RX path 606 (e.g., estimate respective RSB values, respective LOFT values, GEs, PEs, etc.) based on comparing the one or more output signals to a calibration signal (e.g., with known parameters) after averaging the number of digital samples, such that filter parameters (e.g., filter coefficients, codes, etc.) may be determined to mitigate the estimated distortion effects. That is, the effects of the distortions on the calibration signal (e.g., which may be indicative of how the distortions would affect other communications) may be identified based on averaging the number of digital samples and determining an average noise value the digital samples experience, where the average noise value may correspond to distortion measurements (e.g., RSB estimates, LOFT estimates, GE estimates, PE estimates, etc.). Thus, the averaging of the digital samples may result in determining an average distortion measurement (e.g., that still achieves an SNR threshold), and filter parameters may be determined to mitigate the average distortion measurement for transmitted signals, where the filter parameters may then be applied to a filter for subsequent communications. In some cases, the number of averages may be static and / or fixed.

[0130] However, as described previously, based on using the LPM synthesizer for the second frequency synthesizer 614 (e.g., that includes a poorer phase noise profile compared to the first frequency synthesizer 610) may result in a poorer SNR during the calibration procedure for a given number of signal averages. Statically increasing a number of averages to recover the SNR may involve prohibitive time and power penalties. However, using the LPM synthesizer for the second frequency synthesizer 614 also includes one or more technical advantages for the RF configuration 600, such as providing low AuC targets and minimizing on-chip areas for low-tier and / or low-power devices where an available amount of space (e.g., size) of the RF configuration 600 is limited. As such, techniques and signaling are desired to support including the LPM synthesizer for the second frequency synthesizer 614 in the RF configuration 600, while still being able to perform the calibration procedure.

[0131] Accordingly, as described herein, techniques and signaling are described for calibrations using an LPM synthesizer that enable dynamic updates to a number of D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 37 averages for performing the calibration (e.g., dynamic averaging) to recover lost SNR due to the degraded phase noise of the LPM synthesizer. For example, the one or more processors 602 may be configured to output at least one calibration signal 634 and to send the at least one calibration signal 634 through the TX path 604. In some aspects, the one or more processors 602 may continuously send the at least one calibration signal 634 through the TX path 604. In some aspects, the at least one calibration signal 634 may include a multi-tone waveform. Additionally or alternatively, the at least one calibration signal 634 may include an uplink transmission burst, where the uplink transmission burst includes a plurality of waveforms transmitted on an uplink channel. In some aspects, the uplink transmission burst may include an online operation with a plurality of partial uplink allocations. For example, the online operation may include a device (e.g., that implements and / or includes the RF configuration 600) being in continuous or intermittent communication with a wireless network to connect a voice call, a data exchange, or a combination thereof.

[0132] Subsequently, the one or more processors 602 may be configured to obtain at least one output signal from the feedback RX path 606, where the at least one output signal corresponds to the at least one calibration signal 634. In some aspects, the one or more processors 602 may determine to obtain the at least one output signal from the feedback RX path 606 via the internal loopback path 616 or the external loopback path 624.

[0133] For example, the one or more processors 602 may obtain the at least one output signal from the feedback RX path 606 via the internal loopback path 616 based on a device (e.g., that implements and / or includes the RF configuration 600) being configured for an offline mode, where the offline mode includes the device not being communicatively coupled to an external network or wirelessly connected to another entity (e.g., such that the one or more antenna elements 628 are inactive). Additionally or alternatively, the one or more 602 may determine to obtain the at least one output signal from the feedback RX path 606 via the external loopback path 624 based on a device (e.g., that implements and / or includes the RF configuration 600) being configured for the online operation (e.g., the device being in continuous or intermittent communication with a wireless network or another device and / or entity, such that the one or more antenna elements 628 are active). D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 38

[0134] Subsequently, the one or more processors 602 may be configured to determine a number of digitized samples to capture from the at least one output signal. In some aspects, the number of digitized samples may be determined based on the second phase noise profile 650. For example, the second phase noise profile 650 may be characterized by the one or more processors 602 prior to sending the at least one calibration signal 634 and fitted to an equation, and / or the second phase noise profile 650 may be stored in one or more memories coupled to the one or more processors 602 (e.g., the memory 514 as described with reference to FIG. 5).

[0135] In some aspects, the one or more processors 602 may then be configured to perform an averaging 638 of the at least one output signal according to the number of digitized samples. For example, the averaging 638 may include a distortion estimation 640 (e.g., computing one or more average noise values from the at least one output signal using the number of digitized samples). In some aspects, a number of averages performed may refer to averages after digitizing a downconverted signal at the feedback RX path 606.

[0136] In some aspects, the distortion estimation 640 may include estimating a frequency independent residual sideband (FIDRSB) value corresponding to the at least one calibration signal (e.g., for estimating distortions caused by elements and / or components of the TX path 604) and a frequency dependent residual sideband (FDRSB) value corresponding to the at least one output signal (e.g., for estimating distortions caused by elements and / or components of the feedback RX path 606). For example, the FIDRSB value and the FDRSB value may include respective RSB values (e.g., for the TX path 604 and for the feedback RX path 606), respective LOFT values, GE values, PE values, direct current (DC) correction values for LOFT, filter coefficients, or a combination thereof.

[0137] Subsequently, the one or more processors 602 may be configured to determine one or more filter parameters based on the distortion estimation 640 and to store the one or more filter parameters in the one or more memories (e.g., not depicted in the example of FIG. 6A) coupled to the one or more processors 602. For example, the one or more processors 602 may determine and / or adjust the one or more filter parameters based on the FIDRSB value and / or the FDRSB value. In some aspects, the one or more processors 602 may apply a static frequency independent GE correction, a static frequency independent PE correction, or both to the one or more filter parameters on the FIDRSB D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 39 value. Additionally or alternatively, the one or more processors 602 may determine and / or adjust the one or more filter parameters to apply a FDRSB correction based on the FDRSB value.

[0138] Based on whether the one or more processors 602 determines to obtain the at least one output signal using the internal loopback path 616 or the external loopback path 624, the distortion estimation 640 may be performed to determine the one or more filter parameters while a device (e.g., the implements and / or includes the RF configuration 600) is configured for the online operation or the offline mode as described previously. For example, the one or more processors 602 may be configured to determine the one or more filter parameters during the offline mode when using the internal loopback path 616. Additionally or alternatively, the one or more processors 602 may be configured to determine the one or more filter parameters during the online operation when using the external loopback path 624.

[0139] In some aspects, the one or more processors 602 may be configured to filter one or more communication signals using a filter 636 configured to operate in accordance with the one or more filter parameters and to output the one or more filtered communication signals to the TX path 604.

[0140] In some aspects, the one or more processors 602 may be configured to adjust the number of digitized samples to capture from the at least one output signal based on one or more inputs. For example, the one or more inputs may include a desired uplink throughput of one or more communication signals, a target distortion measurement (e.g., target RSB measurement, target LOFT measurement, etc.) to achieve the desired uplink throughput, an amount of time between scheduled uplink transmissions, a transmit power, one or more radio link metrics of the one or more communication signals, an internal temperature of a device that implements and / or includes the RF configuration 600, a bandwidth or bandwidth part being used for the one or more communication signals, or a combination thereof.

[0141] Subsequently, the one or more processors 602 may be configured to perform an additional averaging of the at least one output signal according to the adjusted number of digitized samples. For example, the additional averaging may include computing the one or more average noise values from the at least one output signal using the adjusted number of digitized samples. In some aspects, the one or more processors 602 may then D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 40 be configured to update the one or more filter parameters based on the additional averaging of the one or more average noise values.

[0142] In some aspects, the one or more processors 602 may opportunistically perform the calibration procedure described above during the online operation (e.g., while the device is in continuous or intermittent communication with a wireless network) between scheduled uplink transmissions. For example, a device that implements and / or includes the RF configuration 600 may receive a configuration of a plurality of periodic instances for communications, where a time interval exists between each periodic instance of the plurality of periodic instances. Subsequently, the one or more processors 602 may be configured to send the at least one calibration signal 634 and perform the calibration procedure during the time interval. Additionally or alternatively, the one or more processors 602 may be configured to send the at least one calibration signal 634 and perform the calibration procedure during one or more periodic instances of the plurality of periodic instances.

[0143] In some aspects, each periodic instance of the plurality of periodic instances for communications may include an uplink instance for communications or a downlink instance for communications. Additionally, the time interval may include one or more of: an idle period for DRX operations or DTX operations, a time period configured for downlink communications in a TDD configuration, a scheduling interval configured for power savings for a device that includes and / or implements the RF configuration 600 (e.g., a usleep interval, sleep period, idle period, PDCCH skipping, WUS early indicator (WEI), PEI, etc.), and a predictable time interval for sending the at least one calibration signal, where the at least one calibration signal does not interfere with ongoing communications during the predictable time interval (e.g., the predictable time interval allows unhindered access to the one or more processors 602 and / or RF configuration 600 to perform the calibration procedure described herein).

[0144] In some aspects, the device may be configured for DRX and / or DTX operations. For example, the device may be configured for DRX and / or DTX operations to reduce power consumption and / or conserve battery of the device. In DRX, the device may periodically alternate between an active mode (e.g., “ON” or awake periods) during DRX-on cycles and an inactive mode (e.g., “OFF,” sleep periods, or idle periods). During the active mode and the DRX-on cycles, the device may power on at least a portion of its internal circuitry to monitor for messages or incoming data. Additionally or alternatively, D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 41 in the inactive mode, the device may power down at least a portion of its internal circuitry to reduce power consumption (e.g., battery power consumption), and the device is not expected to receive messages or data in the inactive mode. Additionally or alternatively, during an active mode in DTX, the device may power on at least a portion of its internal circuitry to send one or more messages or outgoing data, and during an inactive mode in DTX, the device may power down at least a portion of its internal circuitry to reduce power consumption.

[0145] Accordingly, the one or more processors 602 may opportunistically perform the calibration procedure based on the configured DRX and / or DTX operations. For example, the one or more processors 602 may perform the calibration procedure using the internal loopback path 616 when the device is not active on transmit or receive (e.g., in an idle mode, inactive mode, or offline mode). Additionally or alternatively, the one or more processors 602 may perform the calibration procedure using the internal loopback path 616 when the device is not active on transmit and active on receive. For example, when a duplexer is present in an RF front-end of the RF configuration 600 (e.g., between the one or more PAs 626 and the one or more antenna elements 628) to provide isolation to a received signal (e.g., which is offset in frequency with respect to the calibration signal based on the different frequency synthesizers) such as in a FDD configuration and the device is not active on transmit, the one or more processors 602 may perform the calibration procedure using the internal loopback path 616. Additionally or alternatively, the one or more processors 602 may perform the calibration procedure using the internal loopback path 616 or the external loopback path 624 when the device is active on receive and not active on transmit based on a configuration where there are dedicated slots for transmit and receive, such as in a TDD configuration. In some aspects, the one or more processors 602 may determine whether the device is not active on transmit based on if the device does not receive any uplink (e.g., transmit) grants for a particular slot and / or the particular slot being a downlink slot for TDD.

[0146] Additionally or alternatively, the one or more processors 602 may perform the calibration procedure when the device may or may not be active on transmit, but is not active on receive. In some aspects, the one or more processors 602 may determine whether the device is not active on receive based on PDCCH skipping (e.g., the device and / or one or more processors 602 know that no receive is needed for one or more subsequent slots and, as such, may use the one or more subsequent slots to perform the calibration D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 42 procedure), based on an inactive portion (e.g., sleep portion) of a slot (e.g., once the device and / or one or more processors 602 decodes a PDCCH and finds no PDSCH is configured or indicated for the rest of the slot, such that the rest of the slot can be used to perform the calibration procedure), and / or based on a configuration (e.g., the device and / or one or more processors 602 know which slots that the device does not need to monitor, such as inactive DRX or idle periods, which may be determined based on WUS, PEI, or other paging messages, and such slots can be used for performing the calibration procedure).

[0147] In some aspects, when the device is active on transmit, the feedback RX path 606 may be simultaneously active for online power estimation using the external loopback path 624. With additional measurement length for the dynamic averaging and some additional digital signal processing, the at least one output signal may capture an online power estimation and may also be used to estimate the distortion in a transmit signal (e.g., for high enough transmit powers). For low power transmit scenarios, some of the distortions may not be a significant contributor to the noise observed from the at least one output signal. Additionally or alternatively, the one or more processors 602 may perform the calibration procedure when the device is active on transmit in a configuration where there are dedicated slots for transmit and receive such as in a TDD configuration, and the calibration procedure may be performed during the dedicated slots using either the internal loopback path 616 or the external loopback path 624.

[0148] In some aspects, for the calibration procedure (e.g., to estimate distortions from the TX path 604) through the internal loopback path 616, the one or more processors 602 may be configured to send multiple repetitions of a short multi-tone waveform for the at least one calibration signal 634 and may be configured to average the received waveform through the feedback RX path 606 for each of these repetitions. In such aspects, more averaging may correspond to sending more repetitions of the waveform and averaging the received waveform over the larger number of repetitions to improve a quality of the distortion estimation 640.

[0149] Additionally or alternatively, the one or more processors 602 may be configured to estimate the distortions using an uplink transmission burst for the at least one calibration signal 634 as described previously. Using the uplink transmission burst may involve a higher amount of signal correlation and signal processing at the feedback RX path 606 to account for the characteristics of a waveform used for the uplink transmission burst (e.g., PUSCH waveform or other waveform type being used for the D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 43 uplink transmission burst) to accurately estimate the distortions (e.g., compared to deterministically estimating the distortion from a multi-tone waveform).

[0150] In some aspects, if a dead time between the scheduled communications is below a time threshold value (e.g., leading to fewer samples than needed for optimal averaging), the one or more processors 602 may determine to use previously determined filter parameters (e.g., FDRSB coefficients, LOFT codes, etc.) and may skip the calibration procedure for dynamic computation of the filter parameters. Additionally or alternatively, the one or more processors 602 may determine to use default filter parameters (e.g., filter parameters configured at manufacturing of the RF configuration 600 and / or defined filter parameters to use). For example, the one or more processors 602 may be configured to compare an amount of time between scheduled transmissions to a threshold time value and may determine one or more additional filter parameters based on the amount of time being below the threshold time value, where the one or more additional filter parameters include filter parameters previously used for a filter, default filter parameters, or a combination thereof.

[0151] Additionally or alternatively, the one or more processors 602 may be configured to maintain a transmit power threshold and may disable the calibration procedure (e.g., for the distortion estimation 640) if a transmit power is below the transmit power threshold, where peak throughput may not be a concern at low powers. In some aspects, the one or more processors 602 may determine to use previously determined filter parameters and / or default filter parameters when a transmit power is below the transmit power threshold rather than perform another calibration procedure to determine filter parameters at lower transmit powers. For example, the one or more processors 602 may be configured to compare a transmit power of one or more communication signals (e.g., sent through the TX path 604) to a threshold power value and may determine one or more additional filter parameters based on the transmit power being below the threshold power value, where the one or more additional filter parameters comprise filter parameters previously used for a filter, default filter parameters, or a combination thereof.

[0152] In some aspects, there may be different variants and / or implementations for performing the calibration procedure to perform the distortion estimation 640. For example, the different variants and / or implementations may be used to achieve an optimum tradeoff between performance, complexity, and power. The below described variants may be used in any combination as suitable in a given implementation. For D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 44 example, for a first variant, the one or more processors 602 may be configured to estimate the distortions (e.g., RSB, LOFT, etc.) and to update the one or more filter parameters for FIDRSB correction (e.g., GE and / or PE parameters), which may be useful in scenarios where the distortion varies across temperature, but this first variant may not change a frequency dependence of the distortions across the baseband frequencies. Additionally or alternatively, for a second variant, the one or more processors 602 may be configured to estimate the distortions and to update filter coefficients for FDRSB correction, which may be useful in scenarios where the distortions change across temperature and this change is due to changing frequency variation of the distortions across the baseband frequencies.

[0153] Additionally or alternatively, for a third variant, if the feedback RX path 606 is configured for online operation (e.g., as described previously), the one or more processors 602 may be configured to use the external loopback path 624 for FDRSB calibration, thereby saving time needed to configure for the internal loopback path 616 (e.g., but with some tradeoff in power since the one or more PAs 626 would remain active). Additionally or alternatively, for a fourth variant, instead of using a multi-tone waveform for the at least one calibration signal 634, the one or more processors 602 may be configured to estimate the distortions from signals (e.g., the at least one output signal) that the feedback RX path 606 captures in the online operation (e.g., an online call) during partial uplink allocations (e.g., if a power level is stable). This fourth variant may leverage additional dead time between uplink transmissions and may still achieve an accurate estimate of the distortions (e.g., with additional complexity in signal processing to extract the distortions from an uplink waveform).

[0154] Additionally or alternatively, for a fifth variant, the one or more processors 602 may be configured to disable the calibration procedure below a certain power threshold. For example, uplink throughput may be limited by the distortions at higher transmit power levels, such that the distortions may not noticeably affect the uplink throughput at lower transmit power levels. Additionally or alternatively, for a sixth variant, the calibration procedure described herein may be performed as a one-time FDRSB calibration (e.g., in the factory) to optimize calibration time versus a compensation accuracy of the distortions.

[0155] In some aspects, the calibration procedure may also enable distinguishing between signal measurements and corresponding distortion measurements for the TX path 604 and for the feedback RX path 606 based on using the first frequency synthesizer D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 45 610 (e.g., HPM synthesizer, high-performance synthesizer, transmit PLL, etc.) for the TX path 604 and using the second frequency synthesizer 614 (e.g., LPM synthesizer, low- performance synthesizer, etc.) for the feedback RX path 606. For example, based on the different frequency synthesizers, after averaging the number of digitized samples from the at least one output signal, a first frequency tone corresponding to distortions caused by components and / or elements of the TX path 604 may be offset (e.g., the offset 646 as shown in the example of FIG. 6B) from a second frequency tone corresponding to distortions caused by components and / or elements of the feedback RX path 606. Additionally, the first frequency tone and the second frequency tone may have differentphase noise^skirts (e.g., the first phase noise profile 648 being different than the secondphase noise profile 650 as shown in the example of FIG. 6B).

[0156] Accordingly, by being able to distinguish between signal measurements and corresponding distortion measurements for the TX path 604 and for the feedback RX path 606, the one or more processors 602 may identify respective distortions caused by elements and / or components of each path and determine the one or more filter parameters to mitigate both distortions.

[0157] FIG. 7 depicts an example illustration 700 of transmission nonidealities and / or distortions for which the calibration procedure described herein is configured to mitigate. In some aspects, the transmission nonidealities and / or distortions depicted in the illustration 700 may implement aspects of or may be implemented by aspects of FIGS. 1–6B. For example, an I signal path 702 and a Q signal path 704 are illustrated that include components of a TX path as described with reference to FIGS. 5 and 6, such as DACs, BBFs, one or more mixers, a DA, one or more PAs. In some aspects, the I signal path 702 may be used to send an I signal 706 that includes a baseband frequency, and the Q signal path 704 may be used to send a Q signal 708 that includes the baseband frequency.

[0158] As described previously, an RSB distortion 714 may be caused by components and / or elements of the I signal path 702 and the Q signal path 704 (e.g., based on an I / Q mismatch and / or I / Q imbalance). In some aspects, the RSB distortion 714 may be modeled and / or determined based on Equation 1 below:where ^ may represent calibration signal as described herein (e.g., a baseband inputwaveform model) with RSB, ^ may represent a desired signal, ^∗may represent an RSB D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 46 signal (e.g., a complex conjugate of the desired signal), ^^andmay represent RSB mismatch parameters for a TX path (e.g., RSB mismatch parameters for the TX path defined in terms of GE and PE), and ^^and ^^may represent RSB mismatch parameters for a feedback RX path (e.g., RSB mismatch parameters for the feedback RX path definedin terms of GE and PE). For example, ^^,^^, ^^, and ^^ may be modeled and / ordetermined based on Equations 2 and 3 below:where ^ may represent a baseband IQ (BBIQ) mismatch for GE and ^ may represent a BBIQ mismatch for PE. Accordingly, respective RSB mismatch parameters for the TX path and for the feedback RX path may be determined with respective ^ and ^ values foreach path (e.g., ^^, ^^ for the TX path and ^^, ^^ for the feedback RX path).

[0159] Additionally or alternatively, a frequency synthesizer 710 may cause a LOFT distortion 712 (e.g., based on a residual LO leakage that occurs due to mismatches, such as I / Q mismatches and / or I / Q imbalance). In some aspects, the LOFT distortion 712 and / or RSB distortion 714 may be modeled and / or determined based on Equations 4, 5, 6, 7, and 8 below:where ^ may represent an output signal (e.g., baseband output signal) obtained by the feedback RX path without considering noise introduced by phase noise of one or more frequency synthesizers (e.g., the frequency synthesizer 710 or the first frequency synthesizer 610 and / or the second frequency synthesizer 614 as described with reference to FIG. 6A), ^ may represent a gain offset for the feedback RX path, ∅ may represent a phase offset for the feedback RX path, ^^(^)may represent a phase noise profile of an LO D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 47 fed and / or generated by the frequency synthesizer 710, ^^may represent multiplying the output signal by the phase noise profile, ^^^may represent generating a number of samples of ^^and taking averages across the number of samples (e.g., average ^ blocks, where the ^ blocks correspond to the number of samples), ^ may represent ^^^∅^^^^, ^ may represent ^^^∅^^^^, ^ may represent ^^^^∅^∗^^^, and ^ may represent ^^^^∅^^∗^^, and ^^ may represent a value of a direct current for the TX path and / or feedback RX path.

[0160] Based on the Equations described above, an optimization equation may be solved to determine RSB and / or LOFT calibration values (e.g., GE value, PE value, etc.) by the feedback RX path (e.g., at one or more processors, such as the one or more processors 602 as described with reference to FIG. 6A). For example, a first equation may be solved first, given by Equation 9 below:where ^ may represent taking a FFT ofSubsequently, the optimization equation may be solved to determine optimal values of the 4x1 matrix of ^ (e.g., ^^^^) by taking a pseudoinverse of ^ and multiplying the pseudoinverse of ^by ^^^ (e.g., ^^^^ = ^^^ !^^^"(^) ∙ ^^^). In some aspects, after solving the optimizationequation, an RSB GE estimate for the TX path (^^), an RSB PE estimate for the TX path (^^), an RSB GE estimate for the feedback RX path (^^), and an RSB PE estimate for the feedback RX path (^^) may be determined based on Equations 10, 11, 12, and 13 below: ^^^ ≈ 2.#^( (10)^)D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 48

[0161] Using the RSB GE and PE estimates given by Equations 10, 11, 12, and 13, filter parameters may be determined to mitigate and / or lessen an impact of the RSB GE and PE estimates for the TX path and the feedback RX path.

[0162] In some aspects, modeling and / or determining the RSB distortion 714 and the LOFT distortion 712 may include one or more assumptions. For example, it may be assumed that any frequency dependent phase shift may be symmetrical to positive and negative frequencies (e.g., apart from RSB and IPN being modeled above through GE, PE, LO phase noise profile). Additionally or alternatively, it may be assumed that tone offsets may be chosen as multiples of frequencies, so a sampling point of ^ blocks may be phase aligned. Additionally or alternatively, it may be assumed that a path gain for thefeedback receive path and a phase offset may be constant across the sampling point of the^ blocks (e.g., except an impact of IPN, which is modeled). Additionally or alternatively,it may be assumed that the phase noise profile (^^(^)) may include impacts of LOs on both the TX path and the feedback RX path.

[0163] Based on the RSB distortion 714 and the LOFT distortion 712, an RF signal 716 may be observed for communication signals, where the RF signal 716 includes a first frequency tone corresponding to the RSB distortion 714, a second frequency tone corresponding to the LOFT distortion 712, and a third frequency tone corresponding to a desired RF signal. Accordingly, the calibration procedure described herein may be configured to mitigate and / or lessen the impact of the RSB distortion 714 and the LOFT distortion 712 on the desired RF signal. Aspects Related to a Method for Performing Calibrations

[0164] FIGS. 8A and 8B depict example flow diagrams for a calibration procedure. In some aspects, FIGS.8A and 8B may implement aspects of or may be implemented by aspects of FIGS. 1–7. For example, FIG. 8A may depict a first flow diagram 800 for the calibration procedure as described with reference to FIG. 6A, and FIG. 8B may depict a second flow diagram 801 for an algorithm for the calibration procedure as described with reference to FIG. 6A, where one or more processors (e.g., the one or more processors 602) may be configured to perform operations of the first flow diagram 800 and the second flow diagram 801.

[0165] In the first flow diagram 800, at 802, the one or more processors may be configured to use an LPM synthesizer for the calibration procedure. For example, the D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 49 LPM synthesizer may be a less expensive synthesizer with a poorer phase noise profile than HPM and / or high-performance synthesizers, but the LPM synthesizer may occupy less chip space than the HPM and / or high-performance synthesizers, which may be advantageous for low-tier and / or low-power devices where AuC targets are lower and chip space is limited.

[0166] At 804, the one or more processors may be configured to perform an opportunistic calibration procedure (e.g., as described with reference to FIG. 6A) to estimate distortions by dynamically changing input parameters, such as a phase noise profile of the LPM synthesizer, a number of averages, a desired uplink throughput target, a target distortion value to achieve the desired uplink throughput target, and dead time between scheduled communications (e.g., in online operations).

[0167] At 806, the one or more processors may be configured to generate one or more filter parameters (e.g., filter coefficients, GE correction, PE correction, frequency independent values, frequency dependent values, etc.) and apply a filter to communication signals according to the one or more filter parameters in an online mode. In some aspects, the one or more processors may be configured to generate the one or more filter parameters in online operations or an offline mode of a device that includes the one or more processors.

[0168] At 808, if target distortion values (e.g., to achieve a desired uplink throughput target) are not met (e.g., due to insufficient SNR), the one or more processors may be configured to increase the number of averages and to repeat the calibration procedure.

[0169] In the second flow diagram 801, at 810, the one or more processors may be configured to use the LPM synthesizer for the calibration procedure. In some aspects, the one or more processors may be configured to use the LPM synthesizer based on a second transmit PLL and / or other HPM or high-performance synthesizer not being available or included on a chip.

[0170] At 812, the one or more processors may be configured to determine a number of averages (e.g., number of digitized samples of an output signal to capture) for performing the calibration procedure. In some aspects, the number of averages may be determined based on a phase noise profile of the LPM synthesizer. Additionally, in some aspects, the one or more processors may be configured to increase the number of averages (e.g., dynamically adjust the number of averages performed and / or the number of D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 50 digitized samples to capture) if a previous calibration procedure failed (e.g., due to insufficient SNR).

[0171] At 814, the one or more processors may be configured to determine if a post- calibration distortion value is greater than a target distortion value (e.g., to achieve a desired uplink throughput target).

[0172] At 816, if the post-calibration distortion value is determined to be greater than the target distortion value, the one or more processors may be configured to generate a filter that mitigates and / or lessens the impact of a distortion determined from the calibration procedure. For example, the filter may be generated according to one or more filter parameters determined from the calibration procedure. Subsequently, the one or more processors may be configured to use the filter for online application. In some aspects, the one or more processors may be configured to update the target distortion value if appropriate (e.g., based on an online scenario).

[0173] At 818, if the post-calibration distortion value is determined to be less than the target distortion value, the one or more processors may be configured to revise the number of averages for performing the calibration procedure. In some aspects, the one or more processors may be configured to take into account any timing constraints when revising the number of averages if the calibration procedure is performed during online operations.

[0174] In some aspects, the operations of the first flow diagram 800 and the second flow diagram 801 may be suitable for low-tier and / or low-power devices (e.g., low-tier UEs, smart watches, etc. with a small area footprint for RFICs) that cannot accommodate multiple transmit PLLs. Additionally, the operations of the first flow diagram 800 and the second flow diagram 801 may assist in achieving an optimum tradeoff between managing distortions (e.g., transmission nonidealities) to achieve an uplink throughput similar to higher tier devices, higher power devices, and / or higher tier integrated circuits (ICs) by dynamically changing the number of averages during a calibration procedure using an LPM synthesizer (e.g., on a feedback RX path) with a sub-optimal phase noise profile.

[0175] FIG.9 depicts an example averaging 900 for a transmission nonideality and / or distortion for which the calibration procedure described herein is configured to mitigate. In some aspects, the averaging 900 may implement aspects of or may be implemented by aspects of FIGS. 1–8B. For example, the averaging 900 may be part of a calibration D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 51 procedure as described herein to determine a distortion value (e.g., RSB estimation, LOFT estimation, GE estimation, PE estimation, etc.).

[0176] As shown in the example of FIG. 9, a distortion measurement 902 may be calculated according to a number of averages that are performed (e.g., using an FFT) on an output signal. For example, the number of averages may correspond to a number of digitized samples captured from the output signal, where the number of digitized samples are averaged together to determine the distortion measurement 902. As can be seen in the example of FIG.9, as the number of averages increases, an error in a distortion parameter estimate (e.g., RSB estimation, LOFT estimation, GE estimation, PE estimation, etc.) may decrease (e.g., get closer to a 0 dB error). As such, increasing the number of averages may correspond to a more accurate distortion estimate, and a filter may be configured to correct the distortion based on the more accurate distortion estimate. Example Operations of a User Equipment Employing an RF Circuit

[0177] FIG. 10 shows a method 1000 for wireless communications by an apparatus, such as UE 104 of FIGS.1 and 3, where the apparatus implements and / or includes an RF circuit, such as an RF circuit that includes the RF configuration 600 as described with reference to FIG. 6A.

[0178] Method 1000 begins at block 1005 with generating at least one calibration signal.

[0179] Method 1000 then proceeds to block 1010 with sending, through a transmit path, the at least one calibration signal.

[0180] Method 1000 then proceeds to block 1015 with obtaining, from a feedback receive path, at least one output signal corresponding to the at least one calibration signal, wherein the at least one output signal is offset in frequency from the at least one calibration signal.

[0181] Method 1000 then proceeds to block 1020 with performing an averaging of the at least one output signal, wherein the averaging comprises computing one or more average noise values from the at least one output signal based at least in part on a number of digitized samples. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 52

[0182] Method 1000 then proceeds to block 1025 with determining one or more filter parameters based on the averaging.

[0183] Method 1000 then proceeds to block 1030 with filtering one or more communication signals using a filter configured to operate in accordance with the one or more filter parameters.

[0184] In certain aspects, method 1000 further includes adjusting the number of digitized samples to capture based at least in part on one or more inputs.

[0185] In certain aspects, method 1000 further includes performing an additional averaging of the at least one output signal according to the adjusted number of digitized samples, wherein the additional averaging comprises computing the one or more average noise values from the at least one output signal using the adjusted number of digitized samples.

[0186] In certain aspects, method 1000 further includes updating the one or more filter parameters based on the additional averaging of the one or more average noise values.

[0187] In certain aspects, the one or more inputs comprise one or more of: a desired uplink throughput of one or more communication signals; a target residual sideband measurement to achieve the desired uplink throughput; an amount of time between scheduled uplink transmissions; a transmit power; one or more radio link metrics of the one or more communication signals; an internal temperature of the apparatus; and a bandwidth or bandwidth part being used for the one or more communication signals.

[0188] In certain aspects, method 1000 further includes receiving a configuration of a plurality of periodic instances for communications, wherein a time interval exists between each periodic instance of the plurality of periodic instances.

[0189] In certain aspects, method 1000 further includes sending the at least one calibration signal during the time interval.

[0190] In certain aspects, method 1000 further includes receiving a configuration of a plurality of periodic instances for communications, wherein a time interval exists between each periodic instance of the plurality of periodic instances. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 53

[0191] In certain aspects, method 1000 further includes sending the at least one calibration signal during one or more periodic instances of the plurality of periodic instances.

[0192] In certain aspects, each periodic instance of the plurality of periodic instances for communications comprises an uplink instance for communications or a downlink instance for communications.

[0193] In certain aspects, the time interval comprises one or more of: an idle period for DRX operations or DTX operations, a time period configured for downlink communications in a TDD configuration, a scheduling interval configured for power savings for the apparatus, and a predictable time interval for sending the at least one calibration signal, wherein the at least one calibration signal does not interfere with ongoing communications during the predictable time interval.

[0194] In certain aspects, method 1000 further includes comparing an amount of time between scheduled transmissions to a threshold time value.

[0195] In certain aspects, method 1000 further includes determining one or more additional filter parameters based at least in part on the amount of time being below the threshold time value, wherein the one or more additional filter parameters comprise filter parameters previously used for a filter, default filter parameters, or a combination thereof.

[0196] In certain aspects, method 1000 further includes comparing a transmit power of one or more communication signals, sent through the transmit path, to a threshold power value.

[0197] In certain aspects, method 1000 further includes determining one or more additional filter parameters based at least in part on the transmit power being below the threshold power value, wherein the one or more additional filter parameters comprise filter parameters previously used for a filter, default filter parameters, or a combination thereof.

[0198] In certain aspects, method 1000 further includes estimating a FIDRSB value corresponding to the at least one calibration signal and a FDRSB value corresponding to the at least one output signal.

[0199] In certain aspects, method 1000 further includes adjusting the one or more filter parameters based at least in part on the FIDRSB value and the FDRSB value. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 54

[0200] In certain aspects, method 1000 further includes applying a static frequency independent GE correction, a static frequency independent PE correction, or both to the one or more filter parameters based at least in part on the FIDRSB value.

[0201] In certain aspects, method 1000 further includes adjusting the one or more filter parameters to apply a FDRSB correction based at least in part on the FDRSB value.

[0202] In certain aspects, the FIDRSB value and the FDRSB value comprise respective residual sideband values, respective LOFT values, gain error values, phase error values, DC correction values for LOFT, filter coefficients, or a combination thereof.

[0203] In certain aspects, method 1000 further includes determining to use an internal loopback path or an external loopback path to obtain the at least one output signal via the feedback receive path based at least in part on the apparatus being configured for online operation or an offline mode.

[0204] In certain aspects, the at least one calibration signal comprises a multi-tone waveform.

[0205] In certain aspects, the uplink transmission burst comprises an online operation with a plurality of partial uplink allocations; and the online operation comprises the apparatus being in continuous or intermittent communication with a wireless network to connect a voice call, a data exchange, or a combination thereof.

[0206] In certain aspects, the at least one calibration signal comprises an uplink transmission burst; and the uplink transmission burst comprises a plurality of waveforms transmitted on an uplink channel.

[0207] In certain aspects, method 1000 further includes determining the one or more filter parameters during an offline mode of the apparatus, wherein the offline mode comprises the apparatus not being communicatively coupled to an external network or wirelessly connected to another entity.

[0208] In certain aspects, method 1000 further includes filtering one or more communication signals using a filter configured to operate in accordance with the one or more filter parameters.

[0209] In certain aspects, method 1000 further includes outputting the one or more filtered communication signals to the transmit path. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 55

[0210] In certain aspects, method 1000, or any aspect related to it, may be performed by an apparatus, such as communications device 1100 of FIG.11, which includes various components operable, configured, or adapted to perform the method 1000. Communications device 1100 is described below in further detail.

[0211] In certain aspects, method 1000 may be performed by the apparatus to realize one or more technical effects or solutions to the aforementioned technical problem(s). For example, based on method 1000, the apparatus may dynamically change a number of averages during online transmission calibrations (e.g., while employing the LPM synthesizer to drive the LO of the feedback receive path) to help achieve a most optimum tradeoff between calibration time and a desired nonideality mitigation. For example, dynamically changing the number of averages may result in a better uplink throughput across temperature while still mitigating distortion issues (e.g., RSB, LOFT, LO folding, etc.).

[0212] Additionally, based on method 1000, the apparatus may avoid a dependence on longer calibration sequences (e.g., performed in a factory using expensive callboxes and / or spectrum analyzers). For example, using an internal loopback-based calibration for an RF circuit may reduce calibration time as compared to performing calibrations for the RF circuit prior to deployment in the device (e.g., on the factory floor). Additionally, the techniques and signaling described herein may include performing the calibrations while a device is online, allowing for distortion correction across temperature and usage environments. In some aspects, the online calibrations may be performed opportunistically (e.g., based on dead time available between active communication slots) with the number of averages being determined for the online calibrations being considered in timing calculations and traded off for online performance.

[0213] Note that FIG. 10 is just one example of a method, and other methods including fewer, additional, or alternative operations are possible consistent with this disclosure. Example Communications Device

[0214] FIG.11 depicts aspects of an example communications device 1100. In some aspects, communications device 1100 is a user equipment, such as UE 104 described above with respect to FIGS. 1 and 3. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 56

[0215] The communications device 1100 includes a processing system 1102 coupled to a transceiver 1162 (e.g., a transmitter and / or a receiver). The transceiver 1162 is configured to transmit and receive signals for the communications device 1100 via an antenna 1164, such as the various signals as described herein. The processing system 1102 may be configured to perform processing functions for the communications device 1100, including processing signals received and / or to be transmitted by the communications device 1100.

[0216] The processing system 1102 includes one or more processors 1104. In various aspects, the one or more processors 1104 may be representative of one or more of receive processor 358, transmit processor 364, TX MIMO processor 366, and / or controller / processor 380, as described with respect to FIG.3. The one or more processors 1104 are coupled to a computer-readable medium / memory 1132 via a bus 1160. In certain aspects, the computer-readable medium / memory 1132 is configured to store instructions (e.g., computer-executable code) that when executed by the one or more processors 1104, enable and cause the one or more processors 1104 to perform the method 1000 described with respect to FIG. 10, or any aspect related to it, including any operations described in relation to FIG. 10. Note that reference to a processor performing a function of communications device 1100 may include one or more processors performing that function of communications device 1100, such as in a distributed fashion.

[0217] In the depicted example, computer-readable medium / memory 1132 stores code for generating 1134, code for sending 1136, code for obtaining 1138, code for performing 1140, code for determining 1142, code for filtering 1144, code for adjusting 1146, code for updating 1148, code for receiving 1150, code for comparing 1152, code for estimating 1154, code for applying 1156, and code for outputting 1158. Processing of the code 1134-1158 may enable and cause the communications device 1100 to perform the method 1000 described with respect to FIG. 10, or any aspect related to it.

[0218] The one or more processors 1104 include circuitry configured to implement (e.g., execute) the code stored in the computer-readable medium / memory 1132, including circuitry for generating 1106, circuitry for sending 1108, circuitry for obtaining 1110, circuitry for performing 1112, circuitry for determining 1114, circuitry for filtering 1116, circuitry for adjusting 1118, circuitry for updating 1120, circuitry for receiving 1122, circuitry for comparing 1124, circuitry for estimating 1126, circuitry for applying 1128, and circuitry for outputting 1130. Processing with circuitry 1106-1130 may enable and D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 57 cause the communications device 1100 to perform the method 1000 described with respect to FIG. 10, or any aspect related to it.

[0219] More generally, means for communicating, transmitting, sending or outputting for transmission may include the transceivers 354, antenna(s) 352, transmit processor 364, TX MIMO processor 366, AI processor 370, and / or controller / processor 380 of the UE 104 illustrated in FIG. 3, transceiver 1162 and / or antenna 1164 of the communications device 1100 in FIG. 11, and / or one or more processors 1104 of the communications device 1100 in FIG. 11. Means for communicating, receiving or obtaining may include the transceivers 354, antenna(s) 352, receive processor 358, AI processor 370, and / or controller / processor 380 of the UE 104 illustrated in FIG. 3, transceiver 1162 and / or antenna 1164 of the communications device 1100 in FIG. 11, and / or one or more processors 1104 of the communications device 1100 in FIG. 11. Example Clauses

[0220] Implementation examples are described in the following numbered clauses:

[0221] Clause 1: An apparatus configured for wireless communications comprising: one or more processors configured to output at least one calibration signal; a transmit path coupled to the one or more processors, the transmit path comprising: a first frequency synthesizer covering a first area and configured to consume a first amount of power; and one or more first mixers coupled to the first frequency synthesizer, wherein: the first frequency synthesizer is configured to feed a first LO signal to the one or more first mixers; and the first LO signal comprises a first frequency tone with a first phase noise profile; and a feedback receive path selectively coupled to the transmit path, the feedback receive path comprising: a second frequency synthesizer covering a second area and configured to consume a second amount of power, wherein: the second area is smaller than the first area; and the second amount of power is less than the first amount of power; and one or more second mixers coupled to the second frequency synthesizer, wherein: the second frequency synthesizer is configured to feed a second LO signal to the one or more second mixers; the second LO signal comprises a second frequency tone with a second phase noise profile; the second frequency tone is offset from the first frequency tone; and the second phase noise profile comprises a wider phase profile than the first phase noise profile. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 58

[0222] Clause 2: The apparatus of Clause 1, further comprising a loopback path coupled between the transmit path and the feedback receive path, wherein: the loopback path comprises one or more switches; and the one or more processors are configured to cause the apparatus to obtain at least one output signal from the feedback receive path via the loopback path, wherein the at least one output signal corresponds to the at least one calibration signal.

[0223] Clause 3: The apparatus of Clause 2, wherein the loopback path comprises an internal loopback path comprising a driver amplifier, one or more low-noise amplifiers, and a closed switch coupled to the driver amplifier and the one or more low-noise amplifiers.

[0224] Clause 4: The apparatus of Clause 2, wherein: the loopback path comprises an external loopback path comprising a driver amplifier, one or more power amplifiers, one or more low-noise amplifiers, one or more antenna elements, a first closed switch coupled to the driver amplifier and the one or more power amplifiers, and a second closed switch coupled to: the one or more power amplifiers, the one or more antenna elements, and the one or more low-noise amplifiers; and the one or more processors are configured to cause the apparatus to obtain the at least one output signal via the external loopback path based at least in part on the apparatus being configured for online operation, wherein the online operation comprises the apparatus being in continuous or intermittent communication with a wireless network to connect a voice call, a data exchange, or a combination thereof.

[0225] Clause 5: The apparatus of any one of Clauses 1-4, wherein the one or more processors are configured to cause the apparatus to: send, through the transmit path, the at least one calibration signal; obtain, from the feedback receive path via a loopback path coupled between the transmit path and the feedback receive path, at least one output signal, wherein the at least one output signal corresponds to the at least one calibration signal and the at least one output signal is offset in frequency from the at least one calibration signal based at least in part on an offset in frequency between the second frequency tone and the first frequency tone; determine a number of digitized samples to capture from the at least one output signal, wherein the number of digitized samples is determined based at least in part the second phase noise profile; perform an averaging of the at least one output signal according to the number of digitized samples, wherein the averaging comprises computing one or more average noise values from the at least one D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 59 output signal using the number of digitized samples; determine one or more filter parameters based on the one or more average noise values; and store the one or more filter parameters in one or more memories coupled to the one or more processors.

[0226] Clause 6: The apparatus of Clause 5, wherein the one or more processors are configured to cause the apparatus to: adjust the number of digitized samples to capture based at least in part on one or more inputs; perform an additional averaging of the at least one output signal according to the adjusted number of digitized samples, wherein the additional averaging comprises computing the one or more average noise values from the at least one output signal using the adjusted number of digitized samples; and update the one or more filter parameters based on the additional averaging of the one or more average noise values.

[0227] Clause 7: The apparatus of Clause 6, wherein the one or more inputs comprise one or more of: a desired uplink throughput of one or more communication signals; a target residual sideband measurement to achieve the desired uplink throughput; an amount of time between scheduled uplink transmissions; a transmit power; one or more radio link metrics of the one or more communication signals; an internal temperature of the apparatus; and a bandwidth or bandwidth part being used for the one or more communication signals.

[0228] Clause 8: The apparatus of Clause 5, wherein the one or more processors are configured to cause the apparatus to: receive a configuration of a plurality of periodic instances for communications, wherein a time interval exists between each periodic instance of the plurality of periodic instances; and send the at least one calibration signal during the time interval, during one or more periodic instances of the plurality of periodic instances, or a combination thereof.

[0229] Clause 9: The apparatus of Clause 8, wherein: each periodic instance of the plurality of periodic instances for communications comprises an uplink instance for communications or a downlink instance for communications; and the time interval comprises one or more of: an idle period for DRX operations or DTX operations, a time period configured for downlink communications in a TDD configuration, a scheduling interval configured for power savings for the apparatus, and a predictable time interval for sending the at least one calibration signal, wherein the at least one calibration signal does not interfere with ongoing communications during the predictable time interval. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 60

[0230] Clause 10: The apparatus of Clause 5, wherein the one or more processors are configured to cause the apparatus to: compare an amount of time between scheduled transmissions to a threshold time value; and determine one or more additional filter parameters based at least in part on the amount of time being below the threshold time value, wherein the one or more additional filter parameters comprise filter parameters previously used for a filter, default filter parameters, or a combination thereof.

[0231] Clause 11: The apparatus of Clause 5, wherein the one or more processors are configured to cause the apparatus to:: compare a transmit power of one or more communication signals, sent through the transmit path, to a threshold power value; and determine one or more additional filter parameters based at least in part on the transmit power being below the threshold power value, wherein the one or more additional filter parameters comprise filter parameters previously used for a filter, default filter parameters, or a combination thereof.

[0232] Clause 12: The apparatus of Clause 5, wherein the one or more processors are configured to cause the apparatus to: estimate a FIDRSB value corresponding to the at least one calibration signal and a FDRSB value corresponding to the at least one output signal; and adjust the one or more filter parameters based at least in part on the FIDRSB value and the FDRSB value.

[0233] Clause 13: The apparatus of Clause 12, wherein the one or more processors are configured to cause the apparatus to apply a static frequency independent GE correction, a static frequency independent PE correction, or both to the one or more filter parameters based at least in part on the FIDRSB value.

[0234] Clause 14: The apparatus of Clause 12, wherein the one or more processors are configured to cause the apparatus to adjust the one or more filter parameters to apply a FDRSB correction based at least in part on the FDRSB value.

[0235] Clause 15: The apparatus of Clause 12, wherein: the FIDRSB value and the FDRSB value comprise respective residual sideband values, respective LOFT values, gain error values, phase error values, DC correction values for LOFT, filter coefficients, or a combination thereof.

[0236] Clause 16: The apparatus of Clause 5, wherein the at least one calibration signal comprises a multi-tone waveform. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 61

[0237] Clause 17: The apparatus of Clause 5, wherein: the at least one calibration signal comprises an uplink transmission burst; and the uplink transmission burst comprises a plurality of waveforms transmitted on an uplink channel.

[0238] Clause 18: The apparatus of Clause 17, wherein: the uplink transmission burst comprises an online operation with a plurality of partial uplink allocations; and the online operation comprises the apparatus being in continuous or intermittent communication with a wireless network to connect a voice call, a data exchange, or a combination thereof.

[0239] Clause 19: The apparatus of Clause 5, wherein the one or more processors are configured to cause the apparatus to determine the one or more filter parameters during an offline mode of the apparatus, wherein the offline mode comprises the apparatus not being communicatively coupled to an external network or wirelessly connected to another entity.

[0240] Clause 20: The apparatus of Clause 5, wherein the one or more processors are configured to cause the apparatus to: filter one or more communication signals using a filter configured to operate in accordance with the one or more filter parameters; and output the one or more filtered communication signals to the transmit path.

[0241] Clause 21: A method for wireless communications by an apparatus comprising: generating at least one calibration signal; sending, through a transmit path, the at least one calibration signal; obtaining, from a feedback receive path, at least one output signal corresponding to the at least one calibration signal, wherein the at least one output signal is offset in frequency from the at least one calibration signal; performing an averaging of the at least one output signal, wherein the averaging comprises computing one or more average noise values from the at least one output signal based at least in part on a number of digitized samples; determining one or more filter parameters based on the averaging; and filtering one or more communication signals using a filter configured to operate in accordance with the one or more filter parameters.

[0242] Clause 22: The method of Clause 21, further comprising: adjusting the number of digitized samples to capture based at least in part on one or more inputs; performing an additional averaging of the at least one output signal according to the adjusted number of digitized samples, wherein the additional averaging comprises computing the one or more average noise values from the at least one output signal using the adjusted number D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 62 of digitized samples; and updating the one or more filter parameters based on the additional averaging of the one or more average noise values.

[0243] Clause 23: The method of Clause 22, wherein the one or more inputs comprise one or more of: a desired uplink throughput of one or more communication signals; a target residual sideband measurement to achieve the desired uplink throughput; an amount of time between scheduled uplink transmissions; a transmit power; one or more radio link metrics of the one or more communication signals; an internal temperature of the apparatus; and a bandwidth or bandwidth part being used for the one or more communication signals.

[0244] Clause 24: The method of any one of Clauses 21-23, further comprising: receiving a configuration of a plurality of periodic instances for communications, wherein a time interval exists between each periodic instance of the plurality of periodic instances; and sending the at least one calibration signal during the time interval.

[0245] Clause 25: The method of any one of Clauses 21-24, further comprising: receiving a configuration of a plurality of periodic instances for communications, wherein a time interval exists between each periodic instance of the plurality of periodic instances; and sending the at least one calibration signal during one or more periodic instances of the plurality of periodic instances.

[0246] Clause 26: The method of any one of Clauses 21-25, further comprising: comparing an amount of time between scheduled transmissions to a threshold time value; and determining one or more additional filter parameters based at least in part on the amount of time being below the threshold time value, wherein the one or more additional filter parameters comprise filter parameters previously used for a filter, default filter parameters, or a combination thereof.

[0247] Clause 27: The method of any one of Clauses 21-26, further comprising: comparing a transmit power of one or more communication signals, sent through the transmit path, to a threshold power value; and determining one or more additional filter parameters based at least in part on the transmit power being below the threshold power value, wherein the one or more additional filter parameters comprise filter parameters previously used for a filter, default filter parameters, or a combination thereof. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 63

[0248] Clause 28: The method of any one of Clauses 21-27, further comprising: estimating a FIDRSB value corresponding to the at least one calibration signal and a FDRSB value corresponding to the at least one output signal; and adjusting the one or more filter parameters based at least in part on the FIDRSB value and the FDRSB value.

[0249] Clause 29: The method of Clause 28, further comprising applying a static frequency independent GE correction, a static frequency independent PE correction, or both to the one or more filter parameters based at least in part on the FIDRSB value.

[0250] Clause 30: The method of Clause 28, further comprising adjusting the one or more filter parameters to apply a FDRSB correction based at least in part on the FDRSB value.

[0251] Clause 31: The method of Clause 28, wherein the FIDRSB value and the FDRSB value comprise respective residual sideband values, respective LOFT values, gain error values, phase error values, DC correction values for LOFT, filter coefficients, or a combination thereof.

[0252] Clause 32: The method of any one of Clauses 21-31, further comprising determining to use an internal loopback path or an external loopback path to obtain the at least one output signal via the feedback receive path based at least in part on the apparatus being configured for online operation or an offline mode.

[0253] Clause 33: The method of any one of Clauses 21-32, wherein the at least one calibration signal comprises a multi-tone waveform.

[0254] Clause 35: The method of Clause 33, wherein: the uplink transmission burst comprises an online operation with a plurality of partial uplink allocations; and the online operation comprises the apparatus being in continuous or intermittent communication with a wireless network to connect a voice call, a data exchange, or a combination thereof.

[0255] Clause 34: The method of any one of Clauses 21-33, wherein: the at least one calibration signal comprises an uplink transmission burst; and the uplink transmission burst comprises a plurality of waveforms transmitted on an uplink channel.

[0256] Clause 36: The method of any one of Clauses 21-35, further comprising determining the one or more filter parameters during an offline mode of the apparatus, wherein the offline mode comprises the apparatus not being communicatively coupled to an external network or wirelessly connected to another entity. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 64

[0257] Clause 37: The method of any one of Clauses 21-36, further comprising: filtering one or more communication signals using a filter configured to operate in accordance with the one or more filter parameters; and outputting the one or more filtered communication signals to the transmit path.

[0258] Clause 38: One or more apparatuses, comprising: one or more memories comprising executable instructions; and one or more processors configured to execute the executable instructions and cause the one or more apparatuses to perform a method, or implement an apparatus, in accordance with any one of Clauses 1-37.

[0259] Clause 39: One or more apparatuses, comprising: one or more memories; and one or more processors, coupled to the one or more memories, configured to cause the one or more apparatuses to perform a method, or implement an apparatus, in accordance with any one of Clauses 1-37.

[0260] Clause 40: One or more apparatuses, comprising: one or more memories; and one or more processors, coupled to the one or more memories, configured to perform a method, or implement an apparatus, in accordance with any one of Clauses 1-37.

[0261] Clause 41: One or more apparatuses, comprising means for performing a method, or means for implementing an apparatus, in accordance with any one of Clauses 1-37.

[0262] Clause 42: One or more non-transitory computer-readable media comprising executable instructions that, when executed by one or more processors of one or more apparatuses, cause the one or more apparatuses to perform a method, or implement an apparatus, in accordance with any one of Clauses 1-37.

[0263] Clause 43: One or more computer program products embodied on one or more computer-readable storage media comprising code for performing a method, or implementing an apparatus, in accordance with any one of Clauses 1-37. Additional Considerations

[0264] The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein are not limiting of the scope, applicability, or aspects set forth in the claims. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, changes D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 65 may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various actions may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method that is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

[0265] The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, an AI processor, a DSP, an ASIC, a FPGA or other PLD, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a system on a chip (SoC), or any other such configuration.

[0266] As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

[0267] As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like. D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 66

[0268] As used herein, “coupled to” and “coupled with” generally encompass direct coupling and indirect coupling (e.g., including intermediary coupled aspects) unless stated otherwise. For example, stating that a processor is coupled to a memory allows for a direct coupling or a coupling via an intermediary aspect, such as a bus.

[0269] The methods disclosed herein comprise one or more actions for achieving the methods. The method actions may be interchanged with one another 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 specific actions may be modified without departing from the scope of the claims. Further, the various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and / or software component(s) and / or module(s), including, but not limited to a circuit, an ASIC, or processor.

[0270] The following claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims. Reference to an element in the singular is not intended to mean only one unless specifically so stated, but rather “one or more.” The subsequent use of a definite article (e.g., “the” or “said”) with an element (e.g., “the processor”) is not intended to invoke a singular meaning (e.g., “only one”) on the element unless otherwise specifically stated. For example, reference to an element (e.g., “a processor,” “a controller,” “a memory,” “a transceiver,” “an antenna,” “the processor,” “the controller,” “the memory,” “the transceiver,” “the antenna,” etc.), unless otherwise specifically stated, 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 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.” Where reference is made to one or more elements performing functions (e.g., steps of a method), one element may perform all functions, or more than one element may collectively perform the functions. When more than one element collectively performs the functions, each function need not be performed by each of those elements (e.g., different functions may be performed by different elements) and / or each function need not be performed in whole by only one element (e.g., different elements may perform different sub-functions of a function). Similarly, where reference is made to one or more elements configured to cause another element (e.g., an apparatus) to perform functions, one element may be configured to cause the other element to perform all D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 67 functions, or more than one element may collectively be configured to cause the other element to perform the functions. Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. D&S Ref. No.: QCM2402797WO

Claims

Qualcomm Ref. No.: 2402797WO 68 CLAIMS 1. An apparatus configured for wireless communications comprising: one or more processors configured to output at least one calibration signal; a transmit path coupled to the one or more processors, the transmit path comprising: a first frequency synthesizer covering a first area and configured to consume a first amount of power; and one or more first mixers coupled to the first frequency synthesizer, wherein: the first frequency synthesizer is configured to feed a first local oscillator (LO) signal to the one or more first mixers; and the first LO signal comprises a first frequency tone with a first phase noise profile; and a feedback receive path selectively coupled to the transmit path, the feedback receive path comprising: a second frequency synthesizer covering a second area and configured to consume a second amount of power, wherein: the second area is smaller than the first area; and the second amount of power is less than the first amount of power; and one or more second mixers coupled to the second frequency synthesizer, wherein: the second frequency synthesizer is configured to feed a second LO signal to the one or more second mixers; the second LO signal comprises a second frequency tone with a second phase noise profile; the second frequency tone is offset from the first frequency tone; and the second phase noise profile comprises a wider phase profile than the first phase noise profile.

2. The apparatus of claim 1, further comprising a loopback path coupled between the transmit path and the feedback receive path, wherein: D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 69 the loopback path comprises one or more switches; and the one or more processors are configured to cause the apparatus to obtain at least one output signal from the feedback receive path via the loopback path, wherein the at least one output signal corresponds to the at least one calibration signal.

3. The apparatus of claim 2, wherein the loopback path comprises an internal loopback path comprising a driver amplifier, one or more low-noise amplifiers, and a closed switch coupled to the driver amplifier and the one or more low-noise amplifiers.

4. The apparatus of claim 2, wherein: the loopback path comprises an external loopback path comprising a driver amplifier, one or more power amplifiers, one or more low-noise amplifiers, one or more antenna elements, a first closed switch coupled to the driver amplifier and the one or more power amplifiers, and a second closed switch coupled to: the one or more power amplifiers, the one or more antenna elements, and the one or more low-noise amplifiers; and the one or more processors are configured to cause the apparatus to obtain the at least one output signal via the external loopback path based at least in part on the apparatus being configured for online operation, wherein the online operation comprises the apparatus being in continuous or intermittent communication with a wireless network to connect a voice call, a data exchange, or a combination thereof.

5. The apparatus of claim 1, wherein the one or more processors are configured to cause the apparatus to: send, through the transmit path, the at least one calibration signal; obtain, from the feedback receive path via a loopback path coupled between the transmit path and the feedback receive path, at least one output signal, wherein the at least one output signal corresponds to the at least one calibration signal and the at least one output signal is offset in frequency from the at least one calibration signal based at least in part on an offset in frequency between the second frequency tone and the first frequency tone; determine a number of digitized samples to capture from the at least one output signal, wherein the number of digitized samples is determined based at least in part the second phase noise profile; D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 70 perform an averaging of the at least one output signal according to the number of digitized samples, wherein the averaging comprises computing one or more average noise values from the at least one output signal using the number of digitized samples; determine one or more filter parameters based on the one or more average noise values; and store the one or more filter parameters in one or more memories coupled to the one or more processors.

6. The apparatus of claim 5, wherein the one or more processors are configured to cause the apparatus to: adjust the number of digitized samples to capture based at least in part on one or more inputs; perform an additional averaging of the at least one output signal according to the adjusted number of digitized samples, wherein the additional averaging comprises computing the one or more average noise values from the at least one output signal using the adjusted number of digitized samples; and update the one or more filter parameters based on the additional averaging of the one or more average noise values.

7. The apparatus of claim 6, wherein the one or more inputs comprise one or more of: a desired uplink throughput of one or more communication signals; a target residual sideband measurement to achieve the desired uplink throughput; an amount of time between scheduled uplink transmissions; a transmit power; one or more radio link metrics of the one or more communication signals; an internal temperature of the apparatus; and a bandwidth or bandwidth part being used for the one or more communication signals.

8. The apparatus of claim 5, wherein the one or more processors are configured to cause the apparatus to: receive a configuration of a plurality of periodic instances for communications, wherein a time interval exists between each periodic instance of the plurality of periodic instances; and D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 71 send the at least one calibration signal during the time interval, during one or more periodic instances of the plurality of periodic instances, or a combination thereof.

9. The apparatus of claim 8, wherein: each periodic instance of the plurality of periodic instances for communications comprises an uplink instance for communications or a downlink instance for communications; and the time interval comprises one or more of: an idle period for discontinuous reception (DRX) operations or discontinuous transmission (DTX) operations, a time period configured for downlink communications in a time division duplexing (TDD) configuration, a scheduling interval configured for power savings for the apparatus, and a predictable time interval for sending the at least one calibration signal, wherein the at least one calibration signal does not interfere with ongoing communications during the predictable time interval.

10. The apparatus of claim 5, wherein the one or more processors are configured to cause the apparatus to: compare an amount of time between scheduled transmissions to a threshold time value; and determine one or more additional filter parameters based at least in part on the amount of time being below the threshold time value, wherein the one or more additional filter parameters comprise filter parameters previously used for a filter, default filter parameters, or a combination thereof.

11. The apparatus of claim 5, wherein the one or more processors are configured to cause the apparatus to: compare a transmit power of one or more communication signals, sent through the transmit path, to a threshold power value; and determine one or more additional filter parameters based at least in part on the transmit power being below the threshold power value, wherein the one or more additional filter parameters comprise filter parameters previously used for a filter, default filter parameters, or a combination thereof.

12. The apparatus of claim 5, wherein the one or more processors are configured to cause the apparatus to: D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 72 estimate a frequency independent residual sideband (FIDRSB) value corresponding to the at least one calibration signal and a frequency dependent residual sideband (FDRSB) value corresponding to the at least one output signal; and adjust the one or more filter parameters based at least in part on the FIDRSB value and the FDRSB value.

13. The apparatus of claim 12, wherein the one or more processors are configured to cause the apparatus to apply a static frequency independent gain error (GE) correction, a static frequency independent phase error (PE) correction, or both to the one or more filter parameters based at least in part on the FIDRSB value.

14. The apparatus of claim 12, wherein the one or more processors are configured to cause the apparatus to adjust the one or more filter parameters to apply a FDRSB correction based at least in part on the FDRSB value.

15. The apparatus of claim 12, wherein the FIDRSB value and the FDRSB value comprise respective residual sideband values, respective LO feedthrough (LOFT) values, gain error values, phase error values, direct current (DC) correction values for LOFT, filter coefficients, or a combination thereof.

16. The apparatus of claim 5, wherein the at least one calibration signal comprises a multi-tone waveform.

17. The apparatus of claim 5, wherein: the at least one calibration signal comprises an uplink transmission burst; and the uplink transmission burst comprises a plurality of waveforms transmitted on an uplink channel.

18. The apparatus of claim 17, wherein: the uplink transmission burst comprises an online operation with a plurality of partial uplink allocations; and the online operation comprises the apparatus being in continuous or intermittent communication with a wireless network to connect a voice call, a data exchange, or a combination thereof.

19. An apparatus configured for wireless communications, comprising: one or more memories comprising processor-executable instructions; D&S Ref. No.: QCM2402797WOQualcomm Ref. No.: 2402797WO 73 one or more processors; a transmit path coupled to the one or more processors; and a feedback receive path selectively coupled to the transmit path, wherein the one or more processors are configured to execute the processor- executable instructions and cause the apparatus to: send, through the transmit path, at least one calibration signal; obtain, from the feedback receive path, at least one output signal corresponding to the at least one calibration signal, wherein the at least one output signal is offset in frequency from the at least one calibration signal; perform an averaging of the at least one output signal, wherein the averaging comprises computing one or more average noise values from the at least one output signal based at least in part on a number of digitized samples; determine one or more filter parameters based on the averaging; and filter one or more communication signals using a filter configured to operate in accordance with the one or more filter parameters.

20. A method for wireless communications by an apparatus comprising: generating at least one calibration signal; sending, through a transmit path, the at least one calibration signal; obtaining, from a feedback receive path, at least one output signal corresponding to the at least one calibration signal, wherein the at least one output signal is offset in frequency from the at least one calibration signal; performing an averaging of the at least one output signal, wherein the averaging comprises computing one or more average noise values from the at least one output signal based at least in part on a number of digitized samples; determining one or more filter parameters based on the averaging; and filtering one or more communication signals using a filter configured to operate in accordance with the one or more filter parameters. D&S Ref. No.: QCM2402797WO

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