CN113676433B

CN113676433B - Method and device for transmitting IQ mismatch calibration

Info

Publication number: CN113676433B
Application number: CN202110526759.3A
Authority: CN
Inventors: E.奈比; 宋基逢; P.达雅尔
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2020-05-15
Filing date: 2021-05-14
Publication date: 2024-04-16
Anticipated expiration: 2041-05-14
Also published as: CN113676433A; KR20210141347A

Abstract

A method of pre-compensating for transmitter in-phase (I) and quadrature (Q) mismatch (IQMM), the method may comprise: transmitting the signal through an up-converter of the transmit path to provide an up-converted signal; determining the upconverted signal; determining one or more IQMM parameters of the transmit path based on the determined up-converted signal; and determining one or more precompensation parameters for the transmit path based on the one or more IQMM parameters for the transmit path. In some embodiments, the up-converted signal through the receive feedback path may be determined. In some embodiments, the up-converted signal may be determined by an envelope detector.

Description

Method and device for transmitting IQ mismatch calibration

Cross Reference to Related Applications

The present application claims priority and the benefit of U.S. provisional patent application No. 63/025,980 entitled "Transmitter Frequency-Dependent In-Phase and Quadrature Mismatch Calibration," filed on 5/15 In 2020, which is incorporated herein by reference.

Technical Field

The present disclosure relates generally to quadrature transmitters and, more particularly, to transmitting IQ mismatch calibration.

Background

The quadrature transmitter may include an in-phase (I) path and a quadrature (Q) path. An imbalance between the I path and the Q path, which may be referred to as IQ mismatch (IQMM), may reduce the performance of the transmitter.

The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art.

Disclosure of Invention

A method of pre-compensating for transmitter in-phase (I) and quadrature (Q) mismatch (IQMM), the method may comprise: transmitting a signal through an up-converter of a transmit path to provide an up-converted signal; determining an up-converted signal through a down-converter of the receive feedback path; determining one or more IQMM parameters of the transmit path based on the determined up-converted signal; and determining one or more precompensation parameters for the transmit path based on the one or more IQMM parameters for the transmit path. Determining one or more IQMM parameters of the transmit path may comprise solving a system of equations, a first equation of which may comprise a first component of an up-converted signal and a first parameter at least partially representing an expected frequency response of the transmit path, and a second equation of which may comprise a second component of the up-converted signal and a second parameter at least partially representing a frequency response of the transmit path due to transmitting IQMM. The first equation in the equation may further include a third parameter that is at least partially representative of a gain and a delay of the transmit path. The method may further comprise: determining an IQMM of the receive feedback path by using a first local oscillator for the transmit path and a second local oscillator for the receive path; and determining one or more IQMM parameters of the transmit path based on the determined up-converted signal may comprise processing the up-converted signal to compensate for IQMM in the receive path. The local oscillator for the transmit path may be shifted with respect to the local oscillator for the receive feedback path. The signal may include a first signal at a first frequency, the upconverted signal may include a first upconverted signal, and the method may further include: transmitting a second signal at a second frequency through the upconverter of the transmit path to provide a second upconverted signal, determining a second upconverted signal through a downconverter of the receive feedback path, and determining one or more IQMM parameters of the transmit path based on the determined second upconverted signal.

A method of pre-compensating for transmitter in-phase (I) and quadrature (Q) mismatch (IQMM), the method may comprise: the method includes transmitting a signal through an upconverter of a transmit path to provide an upconverted signal, determining the upconverted signal through an envelope detector, determining one or more IQMM parameters of the transmit path based on the determined upconverted signal, and determining one or more precompensation parameters of the transmit path based on the one or more IQMM parameters of the transmit path. Determining one or more IQMM parameters of the transmit path may comprise: applying a first precompensation parameter to the transmit path; determining a first power of a component of the up-converted signal caused by transmitting an IQMM through the envelope detector based on the first precompensation parameter; applying a second precompensation parameter to the transmit path; and determining a second power of a component of the up-converted signal caused by the transmitting IQMM passing through the envelope detector based on the second pre-compensation parameter. Determining one or more IQMM parameters of the transmit path may further comprise selecting one of the first precompensation parameter or the second precompensation parameter based on the lower of the first power and the second power. The method may further comprise: applying one or more additional precompensation parameters to the transmit path; and determining one or more additional powers of one or more components of the upconverted signal caused by transmitting an IQMM through the envelope detector based on the one or more additional precompensation parameters; and determining the one or more IQMM parameters of the transmit path may comprise selecting one of the first precompensation parameter, the second precompensation parameter or one or more additional precompensation parameters based on the lower of the first power, the second power or one or more additional powers. The signal may include a first signal at a first frequency, the upconverted signal may include a first upconverted signal, and the method may further include: transmitting a second signal at a second frequency through the upconverter of the transmit path to provide a second upconverted signal, determining the second upconverted signal through the envelope detector, and determining one or more IQMM parameters of the transmit path based on the determined second upconverted signal. The method may further include applying a first precompensation parameter and a second precompensation parameter to the transmit path for each of the first and second signals, and the first and second upconverted signals may be determined based on the first and second precompensation parameters, respectively. Determining one or more IQMM parameters of the transmit path may comprise solving the system of equations based on the determined first up-converted signal and second up-converted signal. The first equation in the equation system may include a function of at least a portion of the first precompensation parameter and the second precompensation parameter. The second frequency may be a negative number of the first frequency at baseband. The method may further comprise: scanning the first and second frequencies for each of the first and second precompensation parameters; determining additional first and second up-converted signals based on sweeping the first and second frequencies; and determining one or more IQMM parameters of the transmit path in frequency based on the determined additional up-converted signal. The signal may include a first diphone signal, the upconverted signal may include a first upconverted diphone signal, and the method may further include transmitting a second diphone signal through the upconverter of the transmit path to provide a second upconverted diphone signal, determining the second upconverted diphone signal through the envelope detector, and determining one or more IQMM parameters of the transmit path based on the determined second upconverted diphone signal. Determining one or more IQMM parameters of the transmit path may comprise solving a system of equations based on the determined first and second up-converted diphone signals, and at least one of the equations may comprise a first parameter of a first frequency of the first diphone signal and a second parameter of a second frequency of the first diphone signal. The method may further comprise: scanning a first frequency and a second frequency of at least one of the two-tone signals; determining additional first and second up-converted dual-tone signals based on sweeping the first and second frequencies; and determining one or more IQMM parameters of the transmit path based on the determined additional up-converted dual tone signal.

A system may include: an IQ transmit path comprising an up-converter; an envelope detector arranged to provide an envelope of an up-converted signal from the IQ transmit path; a signal generator arranged to apply a pilot signal to the IQ transmit path; and a signal monitor arranged to capture the envelope of the upconverted signal based on the pilot signal, and a processor configured to: estimating one or more IQ mismatch (IQMM) parameters of the IQ transmit path based on the captured envelope of the up-converted signal, and estimating one or more compensation coefficients of the IQ transmit path from the estimated IQMM parameters. The signal monitor may be arranged to capture the envelope of the up-converted signal passing through a branch of an IQ receiver.

A system may include: an IQ transmit path comprising an up-converter; an IQ receive path comprising a down-converter; a feedback connection arranged to couple an up-converted signal from the IQ transmit path to the IQ receive path; a signal generator arranged to apply a pilot signal to the IQ transmit path; a signal monitor arranged to capture the up-converted signal over the IQ receive path based on the pilot signal, and a processor configured to: one or more IQ mismatch (IQMM) parameters of the IQ transmit path are estimated based on the captured up-converted signal, and one or more compensation coefficients of the IQ transmit path are estimated based on the estimated IQMM parameters.

Drawings

The drawings are not necessarily to scale and for purposes of illustration, elements of similar structure or function are generally indicated by like reference numerals throughout the several views. The drawings are only intended to facilitate the description of the embodiments disclosed herein. The figures do not describe every aspect of the teachings disclosed herein and do not limit the scope of the claims. The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure.

Fig. 1 illustrates an exemplary embodiment of an IQ transmitter that may be used to implement any TX IQMM estimation and/or compensation technique according to the present disclosure.

Fig. 2 illustrates an exemplary embodiment of a complex-valued precompensator (CVC) structure whose coefficients can be estimated according to the present disclosure.

Fig. 3 illustrates an embodiment of a system that may be used to implement TX FD-IQMM calibration using an RX feedback path according to the present disclosure.

Fig. 4 illustrates an exemplary embodiment of a system that may be used to implement TX FD-IQMM calibration using an RX feedback path according to the present disclosure.

Fig. 5 illustrates an exemplary embodiment of a spectrogram of a transmitted and captured (monitored) signal corresponding to some equations according to the present disclosure.

Fig. 6 illustrates an embodiment of a system that may be used to implement TX FD-IQMM calibration using an envelope detector according to the present disclosure.

Fig. 7 illustrates an exemplary embodiment of a system that may be used to implement TX FD-IQMM calibration using an envelope detector according to the present disclosure.

Fig. 8 shows some spectrograms of the transmitted and captured (monitored) signals using the first embodiment of the method of TX IQMM calibration using an envelope detector according to the present invention.

Fig. 9 shows some spectrograms of transmitted and captured (monitored) signals using a third embodiment of a method of TX IQMM calibration using an envelope detector according to the present disclosure.

Fig. 10 illustrates an embodiment of a method for TX IQMM calibration using an RX feedback path according to the present disclosure.

Fig. 11 illustrates an embodiment of a first method for TX IQMM calibration using an envelope detector according to the present disclosure.

Fig. 12 illustrates an embodiment of a second method for TX IQMM calibration using an envelope detector according to the present disclosure.

Fig. 13 illustrates an embodiment of a third method for TX IQMM calibration using an envelope detector according to the present disclosure.

Fig. 14 illustrates an embodiment of a method for pre-compensating a transceiver IQMM in accordance with the present disclosure.

Fig. 15 illustrates another embodiment of a method of pre-compensating a transmitter IQMM according to the present disclosure.

Detailed Description

SUMMARY

The present disclosure includes many inventive principles related to pre-compensating for in-phase (I) and quadrature (Q) mismatch (IQMM) in a quadrature up-conversion transmitter. The pilot signal may be applied to a Transmit (TX) path at baseband and the IQMM corrupted up-converted signal may be captured and processed using various disclosed techniques and algorithms to estimate TX IQMM, which may include frequency independent IQMM (FI-IQMM) and frequency dependent IQMM (FD-IQMM). The estimated IQMM may then be used to determine coefficients of a pre-compensator in the TX path.

In some embodiments, the IQMM corrupted up-converted signal may be captured by a Receive (RX) feedback path with a quadrature down-converter. The single tone pilot signal may be applied at different frequencies and the captured primary and mirror components of the down-converted signal may be used in an equation system to estimate the IQMM parameters of the TX path. The effect of RX IQMM in the RX feedback path may be reduced or eliminated by various disclosed techniques, for example, by using separate local oscillators for the TX and RX paths and/or frequency shifting between the local oscillators using the TX and RX paths.

In some embodiments, the IQMM corrupted up-converted signal may be captured by an envelope detector and processed using various disclosed techniques. In a first approach using an envelope detector, a single tone pilot signal may be applied while one or more pre-compensation parameters are changed. If IQMM is present in the TX path, the single tone pilot signal applied at baseband may produce a signal at the output of the envelope detector, the component of which is twice the frequency of the pilot signal. Thus, the first method may scan one or more precompensation parameters while applying the first single tone pilot signal and select one or more of the parameters to provide the lowest output power from the envelope detector at twice the frequency of the pilot signal. The search may be performed by repeating this process at other frequencies to select one or more parameters for each frequency. The selected parameters may then be used to estimate the IQMM parameters of the TX path.

In a second approach using an envelope detector, one or more TX IQMM parameters for a given frequency may be estimated directly by using two different sets of precompensators to set the negative and positive frequencies of the transmitted single tone pilot signal at the baseband, respectively. Components at the output of the envelope detector that are twice the given frequency can be combined into a set of equations and the frequency dependent gain and phase mismatch at the given frequency can be solved. This process may be repeated to determine frequency-dependent gains and phase mismatches at other frequencies, which may then be used to estimate the IQMM parameters of the TX path.

In a third approach using an envelope detector, various combinations of negative and positive frequencies of the dual tone pilot signal may be applied to the TX path at baseband, respectively. The output of the envelope detector at various frequencies can be combined and solved using a set of equations to directly obtain an estimate of the TX IQMM parameters.

Once the TX IQMM parameters are determined by any of these disclosed techniques, they can be used to determine the coefficients of the precompensators in the TX path.

The principles disclosed herein may have independent utility and may be implemented separately and not every embodiment may utilize every principle. Furthermore, these principles may also be embodied in various combinations, some of which may amplify the benefits of the various principles in a coordinated manner.

TX precompensation

In quadrature up-conversion transmitters, the IQMM between the I and Q branches may create interference between the image frequencies after up-conversion to Radio Frequency (RF) or Intermediate Frequency (IF). Thus, IQMM may reduce system performance by reducing the effective signal to interference plus noise ratio (SINR). The frequency independent IQMM (FI-IQMM) may originate from an imbalance of the mixer, while the frequency dependent IQMM (FD-IQMM) may be caused by a mismatch between the overall frequency responses on the I-path and the Q-path. In some embodiments, only frequency independent IQMM (FI-IQMM) may be compensated. However, in certain applications such as wideband systems (e.g., millimeter wave systems), FI-IQMM compensation alone may not provide adequate performance. Accordingly, some inventive principles of this patent disclosure relate to techniques for providing FD-IQMM compensation for quadrature upconverter transmitters. Further, the TX IQMM may be different from the RX IQMM. Thus, in some embodiments, the calibration method of the TX path according to the present disclosure may be different from the calibration method of the RX path.

Fig. 1 illustrates an exemplary embodiment of an IQ transmitter that may be used to implement any TX IQMM estimation and/or compensation technique according to the present disclosure. The transmitter 100 shown in fig. 1 may include an I signal path including a digital-to-analog converter (DAC) 104 having an impulse response h _ITX The low pass filter 108 of (t) and the mixer 112. Transmitter 100, which may also be referred to as a TX path, may also include a Q signal path including DAC 106, having an impulse response h _QTX A low pass filter 110 and a mixer 114 of (t). The mixers 112, 114 and filters 108, 110 and summing circuit 116 may together form an up-converter. The transmitter 100 may further comprise an IQMM precompensator 118.

In the transmitter, g _TX Not equal to 1 and phi _TX Not 0 may represent TX gain and phase mismatch, respectively, that may produce frequency independent IQ mismatch (FI-IQMM) at the transmitter. Overall frequency response h in the I and Q paths of the TX path _ITX (t) and h _QTX Mismatch between (t) may result in FD-IQMM, i.e. h, in the TX path _ITX (t)≠h _QTX (t). The baseband equivalent of the up-converted signal in the Tx path 100 in the frequency domain (at the output of the mixer) can be expressed as:

Z _TX (f)＝G _1TX (f)U(f)+G _2TX (f)U ^* (-f), 1) wherein U (f) may be the frequency response of the desired baseband (BB) signal at the inputs of analog baseband (ABB) filters 108 and 110 in the TX path, and G _1TX (f) And G _2TX (f) Can be defined as

In equation (2), H _ITX (f) And H _QTX (f) The filters 108 (h _ITX (t)) and filter 110 (h) _QTX (t)) frequency response. In equation (1), G _1TX (f) U (f) may represent the expected TX signal, and G _2TX (f)U ^* (-f) may represent a TX image signal. If there is no IQMM, (g) _TX ＝1、φ _TX =0 and h _ITX (t)＝h _QTX (t))，G _2TX (f) The second term in equation (1) may become zero. Thus, in some embodiments, G _1TX (f) Can represent the expected frequency response of the transmit path, and G _2TX (f) The frequency response of the transmit path due to IQMM may be represented.

In some embodiments according to the present disclosure, one or more IQMM parameters in the transmitter may be estimated, and then the estimated IQMM parameters may be used to determine pre-compensation parameters to compensate for the effects of IQMM in the transmitter 100.

The one or more IQMM parameters may comprise any parameter affected by the IQMM in the TX path, such as gain mismatch g _TX Phase mismatch phi _TX Filter h _ITX (t) and h _QTX (t) (and/or its frequency response H _ITX (f) And H _QTX (f))、G _1TX (f)、G _2TX (f)、V _TX (f) (as described below) and/or the like. In some exemplary embodiments described below, the parameter φ _TX And V _TX (f) May be used as IQMM parameters because, for example, they may reduce the complexity and/or effort involved in mathematical derivation. However, other IQMM parameters may be used in accordance with the present disclosure. For example, in some example embodiments, G _1TX (f) And G _2TX (f) Can be used forTo be used as IQMM parameters, which can be estimated and then used to determine precompensation parameters.

The precompensation parameter may be any parameter that may determine how IQMM precompensator 118 affects IQMM in TX path 100. An example of a precompensation parameter may be the coefficients of the IQMM precompensator 118 (IQMC coefficients), which may be for the BB signal s [ n ]]＝s _j [n]+js _Q [n]Shaping to reduce or eliminate up-converted signal z _TX An image component in (t). Examples of IQMC coefficients that may be obtained based on the estimated IQMM parameters will be described below.

In some embodiments, the above-described IQMM parameter V _TX (f) May depend on the TX gain and filter mismatch, which may be defined as follows

The continuous time frequency f= ±f may be estimated using various calibration algorithms described herein ₁ ,...,±f _K Phase mismatch phi in the intended frequency band _TX And V _TX (f) A. The invention relates to a method for producing a fibre-reinforced plastic composite Then, phi can be used _TX And V _TX (f) To obtain IQ mismatch compensator (IQMC) coefficients of the pre-compensator 118 to reduce TX FD-IQMM.

Fig. 2 illustrates an exemplary embodiment of a complex-valued precompensator (CVC) structure whose coefficients can be estimated according to the present disclosure. The embodiment shown in FIG. 2 may include a delay T _D An integer delay element 200, a complex conjugate block 202, having an impulse response w _TX [n]Complex value filter 204 and adder 206.

The coefficient values of the predistorter shown in fig. 2 may then be expressed as follows, wherein the coefficient values may be entirely or partially removed from TX FD-IQMM of transmitter 100 shown in fig. 1:

wherein the method comprises the steps ofRepresenting the filter w _TX [n]Is a frequency response of (a) to (b). As is apparent from equation (4), the optimal response of the IQMC coefficients may relate to φ _TX And/or V _TX (f) For example, may be estimated using any of the techniques disclosed herein.

In some examples, and depending on implementation details, the methods, expressions, etc. disclosed herein may provide the best value, and thus the indicator "opt" may be used. However, the principles of the present invention are not limited to the embodiments in which the optimum value can be obtained, and the use of "optimum" or "optimal" is not limited to the method, expression, etc. in which the optimum value can be provided.

Some exemplary examples of the CVC structure shown in fig. 2 may include any of the following implementation details. With impulse response w _TX [n]The complex-valued filter 204 of (2) may be implemented as a Finite Impulse Response (FIR) filter. The complex conjugate block 202 may be configured to output a signal s [ n ]]Complex conjugates of, e.g., s [ n ] ] ^* ＝s _I [n]-js _Q [n]. With delay T _D The integer delay element 200 of (1) may be configured to produce a delay in the input signal, e.g., s [ n-T ] _D ]。

The CVC structure shown in fig. 2 is provided as an example for purposes of illustrating the inventive principles of this disclosure, but other IQMM precompensation structures and/or combinations thereof may be used. For example, in some embodiments, a Real Value Compensator (RVC) architecture may be used.

RX feedback path

Fig. 3 illustrates an embodiment of a system that may be used to implement TX FD-IQMM calibration using an RX feedback path according to the present disclosure. The embodiment shown in fig. 3 may include a TX path 300, an RX path 302, a feedback connection 304, and a signal processing unit 306.TX path 300 may include a predistorter 308, a digital-to-analog converter (DAC) 310, an upconverter 314, and a Radio Frequency (RF) transmit block 316.RX path 302 may include an RF receive block 318, a down-converter 320, and an analog-to-digital converter (ADC) 324. In some embodiments, RX path 302 may further include a compensator (not shown). The signal processing unit 306 may include a signal generator 328, a signal capturing unit 330, and a signal processor 332.

The feedback connection 304 may be implemented with any suitable device, such as a switch, coupler, conductor, transmission line, filter, etc. Feedback connection 304 may be coupled to TX path 300 at any location after up-converter 314. Feedback connection 304 may be coupled to RX path 302 at any location prior to down converter 320. In some embodiments, some or all of feedback connection 304 may be integrated with TX path 300 and/or RX path 302.

TX path 300 and RX path 302 may each include an I signal path or branch and a Q signal path or branch. The RF transmit block 316 may include various components for transmitting RF signals, such as power amplifiers, band pass filters, antennas, and the like. The RF receive block 318 may include various components for receiving RF signals, such as an antenna, a bandpass filter, a Low Noise Amplifier (LNA), and the like. The IQMM in TX path 300 may be corrected by IQMM precompensator 308, depending on whether the system is in an operational mode or a calibration mode.

In some embodiments, processor 332 may manage and/or control the overall operation of the system shown in fig. 3. This may include controlling the application of one or more pilot signals to TX path 300, capturing monitored values of the up-converted pilot signals over RX path 302, performing calculations and/or offloading calculations for other resources, providing estimated coefficients to TX precompensator 308, controlling TX precompensator 308 during the transmission and/or transmission of the pilot signals, e.g., by disabling precompensator 308, placing it in a transparent or pass-through state, and so forth.

Although the various components shown in fig. 3 may be shown as separate components, in some embodiments, multiple components and/or their functionality may be combined into a fewer number of components. Likewise, individual components and/or their functions may be distributed among and/or integrated with other components. For example, the signal generator 328 and/or the signal capture unit 330 may be integrated with and/or the functionality of one or more similar components in a modem that may be coupled to the transceiver shown in fig. 3.

The components of the signal processing unit 306 may be implemented in hardware, software, and/or any combination thereof. For example, all or part of the hardware implementations may include combinational logic, sequential logic, timers, counters, registers, gate arrays, amplifiers, synthesizers, multiplexers, modulators, demodulators, filters, vector processors, complex Programmable Logic Devices (CPLDs), field Programmable Gate Arrays (FPGAs), state machines, data converters (such as ADCs and DACs), and/or the like. All or part of the software implementation may include one or more processor cores, memory, program and/or data storage and/or the like, which may be located locally and/or remotely and may be programmed to execute instructions to perform one or more functions of the components of the signal processing unit 306.

Fig. 4 illustrates an exemplary embodiment of a system that may be used to implement TX FD-IQMM calibration using an RX feedback path according to the present disclosure. The embodiment shown in fig. 4 may include a TX path 400, an RX path 402, and an RX feedback connection 403. TX path 400, which is similar to transmitter 100 shown in fig. 1, may include an I signal path including DAC 404, having an impulse response h _ITX The low pass filter 408 of (t) and the mixer 412.TX path 400 may also include a Q signal path including DAC 406 having an impulse response h _QTX A low pass filter 410 and a mixer 414 of (t). The mixers 412 and 414, filters 408 and 410, and summing circuit 416 may together form an up-converter. TX path 400 may further include IQMM precompensator 418.

RX path 402 can include an I signal path including a mixer 426 having an impulse response h _IRX Low pass filter 430 of (t) and ADC 434.RX path 402 may also include a Q signal path including mixer 428, having an impulse response h _QRX The low pass filter 432 of (t) and the ADC 436. The mixers 426 and 428 and filters 430 and 432 may together form a down converter. In some embodiments, RX path 402 may further include an IQMM compensator (not shown) thatMay be disabled or placed in a pass-through state during calibration operations.

In some embodiments, during calibration operations, IQMM pre-compensator 418 may be disabled or placed in pass-through mode such that IQMC may be unitary, thus U (f) =s (f).

To estimate the IQMM parameter phi _TX And V _TX (f) The single-tone signal can be transmitted at frequency f _k Down-applied to the baseband of TX path 400, i.e., U (f) =a _TX δ(f-f _k ) Wherein A is _TX May be an unknown scaling factor that may account for the gain and/or delay between the TX baseband signal generation and the inputs of ABB filters 408 and 410. The IQMM corrupted up-converted signal may be generated by capturing the down-converted signal through the RX feedback path at the primary and mirror frequencies (f _k and-f _k ) The frequency response is monitored, which can be expressed asAnd->Next, the frequency-f may be determined by TX path 400 _k Down-transmitting single-tone signals, i.e.)>And frequency-f _k And f _k The down-converted signals may be denoted as R respectively _3,k ＝R′(-f _k ) And R is _4,k ＝R′(f _k ). Collecting all detection values can provide the following set of equations

Wherein A is _RX The gain and/or delay from RX ABB filters 430 and 432 to RX BB may be represented. In some embodiments, four equations (5) may be time aligned for proper estimation of the IQMM parameters.

Fig. 5 shows an exemplary embodiment of a spectrogram of the transmitted and captured (observed) signal corresponding to equation (5).

The tone signal can be mapped to all selected frequencies over the entire channel band (e.g., f _k ) Sweep frequency to obtain phi using equation (5) _TX And V _TX (f) The estimated value of (2) is as follows

Wherein the method comprises the steps of

In some embodiments of the calibration algorithm described above, it may be assumed that IQMM at the RX feedback path is zero. In some other embodiments, the RX feedback path may also introduce RX IQMM into the observations, which in turn may reduce the accuracy of the estimation of the TX IQMM parameters.

In some embodiments, one or both of the two techniques described below may reduce or eliminate the effect of IQMM in the RX feedback path on the observations of the up-converted pilot signal in accordance with the present disclosure.

In a first technique according to the present disclosure, the RX FD-IQMC may be calibrated in loopback mode using separate Local Oscillators (LOs) of the TX and RX paths (e.g., sweeping the TX LO and using a DC tone at the BB of the TX path while keeping the RX LO unchanged). The BB TX tone may then be swept throughout the frequency to fix both TX LO and RX LO at the same frequency. The TX FD-IQMC coefficients may then be determined. In some embodiments, other steps may be added to post-process the received signal R (f) to estimate φ _TX And V _TX (f) The influence of RX-IQMM was previously removed.

In a second technique according to the present disclosure, a frequency shift may be created between the TX path and the LO of the RX path so that the RX-IQMM may not interfere with the primary signal and the image signal of the TX path. In some embodiments, the frequency shift between LOs may be kept relatively small, e.g., to keep ABB filter responses that the TX main signal and the image signal may monitor substantially symmetrical.

Envelope detector

Fig. 6 illustrates an embodiment of a system that may be used to implement TX FD-IQMM calibration using an envelope detector according to the present disclosure. The system shown in fig. 6 may include a TX path 600 and a signal processing unit 606 that may be configured and/or operated in a manner similar to that shown in fig. 3. Specifically, TX path 600 may include a predistorter 608, a digital-to-analog converter (DAC) 610, an upconverter 614, and a Radio Frequency (RF) transmit block 616. The signal processing unit 606 may include a signal generator 628, a signal capture unit 630, and a signal processor 632.

The system shown in fig. 6 may further include an envelope detector 640 and a signal return path 642. Envelope detector 640, which may be implemented using any suitable means including diodes, filters, etc., may be coupled to TX path 600 at any location after up-converter 614. The return signal path 642 may comprise any suitable device such as a switch, coupler, conductor, transmission line, filter, data converter, etc.

In some embodiments, the envelope detector 640 may provide a signal having, for example, y (t) = |z (t) ² In the form of an output of a (c) signal. In some embodiments, some or all of the envelope detector 640 may be integrated with or with the TX path 600.

In some embodiments, the envelope detector 640 may output the envelope of the IQMM corrupted up-converted signal and feed it back to the signal processing unit 606 without going through a mixer. Thus, the acquired signal may contain only TX IQMM without any RX impairments. Although return signal path 642 is not limited to any particular implementation details, in some examples, either of the I or Q signal paths downstream of the multiplier in the quadrature receiver may be used as the return signal path. This may be convenient, for example, in transceiver systems in which there is already an RX path.

Fig. 7 illustrates an exemplary embodiment of a system that may be used to implement TX FD-IQMM calibration using an envelope detector according to the present disclosure. The system shown in fig. 7 may include a TX path 700, an RX path 702, and an envelope detector 740.

TX path 700, which may be similar to TX path 400 shown in fig. 4, may include an I signal path including DAC 704, having an impulse response h _ITX Low pass filter 708 of (t) and mixer 712.TX path 700 may also include a Q signal path including DAC 706, having an impulse response h _QTX Low pass filter 710 and mixer 714 of (t). The mixers 712 and 714, filters 708 and 710, and summing circuit 716 may together form an up-converter. TX path 700 may further include IQMM precompensator 718.

RX path 702, which may be similar to RX path 402 shown in FIG. 4, may include an I signal path including mixer 726, having an impulse response h _IRX Low pass filter 730 of (t) and ADC 734.RX path 702 may also include a Q signal path including mixer 728 having an impulse response h _QRX The low pass filter 732 of (t) and the ADC 736. The mixers 726 and 728 and filters 730 and 732 may together form a down converter. In some embodiments, RX path 702 may further include an IQMM compensator, which may be disabled or placed in a pass-through state during calibration operations.

The envelope detector 740 may be connected to the TX path 700 at any position after the up-conversion unit. It may also be connected to RX path 702 anywhere after mixers 726 and 728. In the embodiment shown in fig. 7, the envelope detector 740 is connected to the I-path of the RX-path, but may also be connected to the Q-side.

An embodiment of three different methods of estimating TX IQMM using an envelope detector is described below in the context of the exemplary embodiment shown in fig. 7. However, these methods are not limited to these or any other system implementation details.

Method 1

In some embodiments, the method may seek to obtain a frequency that may be ± f ₁ ,...,±f _K Single-tap (single-tap) precompensator filter coefficients for down-cancellation of IQMM. These coefficients can then be used to estimate the IQMM parameter phi _TX And V _TX (f)。

Referring to fig. 8, in some embodiments, if there is any IQMM in the TX link, the frequency-f transmitted at baseband _k Can be generated at the envelope detector with a frequency 2f _k Is a component of the output of the component(s). Thus, it can be at frequency-f _k Transmitting a single tone signal from the baseband of the TX, sweeping the precompensator coefficients (in some embodiments by a tap), and selecting the coefficient that provides the lowest power at the output of the envelope detector at twice the frequency of the BB signal, i.e. 2f _k Thereby finding the frequency f _k Single tap precompensator coefficients (in some embodiments, optimal or optimal coefficients). For a frequency at-f _k The output of the envelope detector path for the down-transmitted tone signal may be denoted r (t), and its response (ignoring the high frequency components) may be denoted as:

the envelope detector output being at frequency 2f _k The frequency response can be expressed as follows

G in the absence of IQMM _2TX (f _k ) May be zero, so R (2 f) in equation (9) _k ) May be zero. By performing a search for the precompensator coefficients, a single tap precompensator setting, i.e. w, can be obtained _TX [n]＝w _TX,0 ×δ[n]So that R (2 f _k ) Can become zero and cancel the frequency f _k IQMM below. For f _k Scanning and obtaining a target T _D =0 byAfter the IQMC coefficients (e.g., optimal coefficients) over all frequency tones represented _TX And V _TX (f) The following can be estimated for the CVC structure

In some embodiments, the search for the precompensator coefficients may be implemented as a broad or exhaustive search. For example, searches may be performed at fixed intervals over a wide range of precompensator settings and/or frequency tones. In some embodiments, the search may be performed in stages. For example, the initial search may be performed at a wider interval, with a coarser precompensator setting and/or frequency tone grid over a wider range. One or more additional searches may then be performed on the finer grid at smaller intervals over one or more smaller areas based on the results of the coarse search.

Method 2

In some embodiments, the method may directly estimate the given frequency f _k The lower IQMM parameters, e.g. by using two different precompensator coefficients and/or setting at f _k And-f _k The single tone signal is separately transmitted. Then a quadratic equation, for example in closed form, can be used for these measurements at frequency 2f _k The lower envelope detector outputs are combined and solved to obtain f _k The frequency dependent gain and phase mismatch. Then, the IQMM parameter Φ can be found _TX And V _TX (f) For example, as each frequency f _k Is a simple function of frequency dependent gain and phase mismatch.

Some exemplary embodiment details may be as follows. For example, for the CVC architecture shown in FIG. 2, frequency f _k And-f _k Can be applied to the TX path at BB alone without any IQMC, e.g. w _TX [n]=0, and the envelope detector output is at frequency 2f _k The frequency response below can be denoted as Y respectively _1,k And Y _2,k . Another group of T-equipped can be selected and applied _D Pre-compensation parameter w [ n ] of delay element of=0]And can transmit a frequency f _k Is a single of (2)A sound signal. The envelope detector outputs at a frequency 2f _k The frequency response below can be expressed as Y _3,k . This gives the following equation

Wherein J ₁ And J ₂ May be a known value, and may be defined as follows

J ₁ ＝1,

Relationships can be usedAnd equations (2) and (3) reformulate equation (11) as

Wherein the method comprises the steps of

Equation (13) can provide six real equations with five real unknowns, namely Re { γ }, im { γ }, re { V } _TX (f _k )},Im{V _TX (f _k )},φ _TX Wherein these equations can be solved to obtain V _TX (f _k ) And phi _TX Is used for the estimation of the estimated value of (a). IQMM parameter V _TX (-f _k ) Estimated asThis parameter may follow h _ITX (t) and h _QTX (t) is a real-valued filter which can be conjugate symmetric in the frequency domain, i.e.>And

method 3

In some embodiments, the method may involve separately measuring the frequencyAnd->A dual tone pilot signal is transmitted. Then, the frequency can be in a closed form, for example, using two quadratic equationsThe envelope detector outputs are then combined and solved for these measurements to directly obtain phi _TX And V _TX (f) At->The following estimation.

Referring to fig. 9, in some embodiments of this method, the transmit frequency may be generated at TX basebandIs a dual-tone signal of->And the time domain signal may be captured at the output of the envelope detector. The frequency response of the time domain signal can be expressed asNext, the frequency can be +.>And->Down-transmitting multitone signals, i.e.)> And the envelope detector output is at frequency +.>The frequency response below can be expressed as +.>Andthen, the multi-tone signal may be at a frequency +. >And->Down send, i.eAnd the captured envelope signal is at a frequency +.>The frequency response below can be expressed as +.>And->The following parameters may be defined:

in combination with all observations, the following nonlinear equation can be provided:

for example, the set of 8 equations with 8 unknowns in equation (15) may be solved using the following steps:

1.

a. the following parameters can be calculated for l=1, 2 and i=1, 2

b.And->Can be calculated as

Wherein i is _k ＝argmax _i (|β _2,i I) and

C.and->Can be calculated as

D.And->Can be calculated as +.>

2. After all ofAnd->Thereafter, wherein->

a.φ _TX Can be estimated as

b.V _TX (f) The estimated value of (2) can be obtained in the following manner

For r=1, 2,

in some embodiments, f _k1 >0 andcan be selected such that the frequency +.> May be different.

Selection of two tone pilot signals (and their positive and negative frequencies)And the resulting envelope detector output signal selected for analysis purposes are for illustration purposes only, other combinations of pilot signals and/or output signals may be used. For example, in the second set of signals in FIG. 9, one may useAnd->Replace->And->Some of the unused signals are shown in dashed lines in fig. 9, but in other embodiments, these signals may be used while other signals may not. Although some embodiments may be described in the context of a dual tone pilot signal, a pilot signal having any number of tones may be used, e.g., triphone, quad tone, etc.

As described above, in some embodiments, the one or more equations that may be obtained using method 3 may include one or more IQMM parameters for two frequencies of the binaural signal. Conversely, in some embodiments using method 2, each equation may include only a single frequency IQMM. Thus, in some examples, and depending on implementation details, different sets of equations may be obtained using different methods.

Obtaining IQMC coefficients

In some embodiments, when for f= ±f ₁ ,...,±f _K Obtaining phi _TX And V _TX (f) These estimates can be used to compensate for FD-IQMM in the TX path. In some exemplary embodiments, a Least Squares (LS) method may be implemented as follows: for a given delay element T _D Can be at frequency f= ±f ₁ ，...,±f _K Lower estimation of parameters given in equation (4)For example, in a Finite Impulse Response (FIR) filter having a length LIn the embodiment of (2), the method can obtain the optimal l tap filterThe filter can minimize W _TX (f) And->Between at frequency f= ±f ₁ ,...,±f _K The Least Squares (LS) error is as follows

Wherein the method comprises the steps ofSum f= [ F ₀ ,...,F _L-1 ]Is a Discrete Fourier Transform (DFT) matrix of size 2K x L. In some embodiments, T _D The value in {0,... For the fixed T _D ，w _TX Can be found as +.>With->Least squares error of (a) is determined. Then, the optimum T _D And filter coefficients>Can be expressed as follows:

although some techniques have been described in the context of a predistorter structure such as the predistorter structure shown in fig. 2, the inventive principles are not limited to these examples and the calibration algorithm according to the present disclosure may also be applied to other IQMC structures. Furthermore, filter coefficients of the IQMC structure may be obtained based on the estimated IQMM parameters using techniques other than LS, and the methods described herein are merely examples for illustrating the inventive principles.

In any of the embodiments disclosed herein, a baseband time domain signal may be captured and converted to a frequency domain signal, e.g., using a Fast Fourier Transform (FFT), to obtain a frequency domain signal (e.g., signal R in fig. 10 _1,k ,…,R _4,k )。

Fig. 10 illustrates an embodiment of a method for TX IQMM calibration using an RX feedback path according to the present disclosure. The method shown in fig. 10 may be used, for example, with the system shown in fig. 4. The method shown in fig. 10 may begin with operation 1000. In operation 1002, a counter k may be initialized to 1. In operation 1004, the method may check the value of the counter k. If K is less than or equal to the maximum value K, the method may proceed to operation 1006 where the frequency f may be at _k A single tone pilot signal is generated and applied to TX path 400 at baseband. In operation 1008, the received pilot signal may be at a frequency f at baseband of the RX path 402 _k And-f _k Captured below and denoted as R respectively _1,k And R is _2,k . In operation 1010, a frequency of-f may be used _k A single tone pilot signal is generated and applied to TX path 400 at baseband. In operation 1012, the received pilot signal may be at frequency-f at baseband of RX path 402 _k And f _k Captured below and denoted as R respectively _3,k And R is _4,k 。

In operation 1014, the method may increment the value of counter k and return to operation 1004, where the method may examine the value of counter k. If K is greater than the maximum value K, the method may proceed to operation 1016 where the pair R is used _1,k ,…,R _4,k Is of the observed value of (2)The method can estimate the IQMM parameter phi _TX And V _TX (f),f＝±f ₁ ,...,±f _K . In operation 1018, the method may use φ _TX And V _TX (f),f＝±f ₁ ,...,±f _K To estimate the coefficients of TX IQMM pre-compensator 418. The method may then end at operation 1020.

As described above, in some embodiments, the time domain signal at BB of RX path 402 may be captured and converted to a frequency domain signal by using, for example, FFT, for example, to obtain R _1,k ,...,R _4,k 。

Fig. 11 illustrates an embodiment of a first method for TX IQMM calibration using an envelope detector according to the present disclosure. The method shown in fig. 11 may be used, for example, with the system shown in fig. 7. The method shown in fig. 11 may begin with operation 1100. In operation 1102, a counter k may be initialized to 1. In operation 1104, the method may check the value of the counter k. If K is less than or equal to the maximum value K, the method may proceed to operation 1106 where a new predistorter setting may be selected from the possible predistorter values. In operation 1108, the frequency-f may be _k A single tone pilot signal is generated and applied to TX path 700 at baseband. In operation 1110, the output of the ABB filter, which may be captured in the envelope detector path, is at a frequency of 2f _k The following signal. In operation 1112, the method may check the power of the captured signal. If the power is a non-negligible value, the method may return to operation 1106. If the power is zero or a negligible value, the method may proceed to operation 1114 where the frequency f may be determined _k The optimal value of the precompensator setting of (c) is set to the current setting. In operation 1116, it may be directed to at f _k The next generated tone signal repeats this process.

In operation 1118, the method may increment the value of counter k and return to operation 1104 whereIn operation, this method may check the value of counter k. If K is greater than the maximum value K, the method may proceed to operation 1120 where a target for + -f is used ₁ ,…,±f _k The method can estimate the IQMM parameter phi _TX And V _TX (f),f＝±f ₁ ,...,±f _K . In operation 1122, the method may use φ _TX And V _TX (f),f＝±f ₁ ,...,±f _K To estimate the coefficients of TX IQMM pre-compensator 718. The method may then end at operation 1124.

Fig. 12 illustrates an embodiment of a second method for TX IQMM calibration using an envelope detector according to the present disclosure. The method shown in fig. 12 may be used, for example, with the system shown in fig. 7. The method shown in fig. 12 may begin with operation 1200. In operation 1202, a counter k may be initialized to 1. In operation 1204, the method may check the value of the counter k. If K is less than or equal to the maximum value K, the method may proceed to operation 1206 where, for example, a first pre-compensator setting without IQMC may be selected. In operation 1208, the method may be at frequency f at BB of the transmit path 700 _k A tone signal is generated and transmitted. The signals at the outputs of ABB filters 730 and 732 in the envelope detector path may be at frequency 2f _k Captured below and denoted as Y _1,k . In some embodiments, the signal may be captured after ADCs 734 and 736. In operation 1210, the method may be at frequency-f at BB of the transmit path 700 _k A tone signal is generated and transmitted. The signals at the outputs of ABB filters 730 and 732 in the envelope detector path may be at frequency 2f _k Captured below and denoted as Y _2,k . At operation 1212, the method may select a second predistorter setting to apply to TX path 700. In operation 1214, the method may be at frequency f at BB of transmit path 700 _k A tone signal is generated and transmitted. The signals at the outputs of ABB filters 730 and 732 in the envelope detector path may be at frequency 2f _k Captured below and denoted as Y _3,k 。

In operation 1216The method may increment the value of counter k and return to operation 1204 where the method may examine the value of counter k. If K is greater than the maximum value K, the method may proceed to operation 1218 where Y is used _1,k 、Y _2,k Y is as follows _3,k For each k, this method can estimate the IQMM parameter Φ _TX And V _TX (f),f＝±f ₁ ,...,±f _K . In operation 1220, the method may use φ _TX And V _TX (f),f＝±f ₁ ,...,±f _K To estimate the coefficients of TX IQMM pre-compensator 718. The method may then end at operation 1222.

Fig. 13 illustrates an embodiment of a third method for TX IQMM calibration using an envelope detector according to the present disclosure. The method shown in fig. 13 may be used, for example, with the system shown in fig. 7. The method shown in fig. 13 may begin with operation 1300. In operation 1302, a counter k may be initialized to 1. In operation 1304, the method may check the value of the counter k. If K is less than or equal to the maximum value K, the method may proceed to operation 1306 where the frequency may be at baseband of TX path 700A diphone signal is generated and transmitted. In operation 1308, the signals at the outputs of ABB filters 730 and 732 in the envelope detector path may be at frequency +.>Captured downwards and denoted as Y respectively _1,k 、Y _2,k 、Y _3,k 、Y _4,k . In operation 1310, the frequency may be +_ at baseband of TX path 700>A binaural signal is generated and transmitted. In operation 1312, the signals at the outputs of ABB filters 730 and 732 in the envelope detector path may be at frequency +.>Lower capture, and are denoted as Y _5,k 、Y _6,k . In operation 1314, the frequency may be +_ at baseband of TX path 700>A binaural signal is generated and transmitted. In operation 1316, the signals at the outputs of ABB filters 730 and 732 in the envelope detector path may be at frequencyLower capture, and are denoted as Y _7,k 、Y _8,k 。

In operation 1318, the method may increment the value of counter k and return to operation 1304, where the method may examine the value of counter k. If K is greater than the maximum value K, the method may proceed to operation 1320 where Y is used _1,k ,…,Y _8,k For each k, this method can estimate the IQMM parameter Φ _TX And V _TX (f),f＝±f ₁ ,...,±f _K . In operation 1322, the method may use φ _TX And V _TX (f),f＝±f ₁ ,...,±f _K To estimate the coefficients of TX IQMM pre-compensator 718. The method may then end at operation 1324.

Fig. 14 illustrates an embodiment of a method for pre-compensating a transceiver IQMM in accordance with the present disclosure. The method may begin at operation 1400. In operation 1402, the method may send a signal through an up-converter of a transmit path to provide an up-converted signal. In operation 1404, the method may determine an upconverted signal through a downconverter of the receive feedback path. In operation 1406, the method may determine one or more IQMM parameters of the transmit path based on the determined up-converted signal, and in operation 1408, the method may determine one or more precompensation parameters of the transmit path based on the one or more IQMM parameters of the transmit path. The method may end at operation 1410.

Fig. 15 illustrates another embodiment of a method of pre-compensating a transmitter IQMM according to the present disclosure. The method may begin at operation 1500. In operation 1502, the method may send a signal through an up-converter of a transmit path to provide an up-converted signal. In operation 1504, the method may determine an up-converted signal that passes through an envelope detector. In operation 1506, the method may determine one or more IQMM parameters of the transmit path based on the determined up-converted signal, and in operation 1508, the method may determine one or more precompensation parameters of the transmit path based on the one or more IQMM parameters of the transmit path. The method may end at operation 1510.

The operations and/or components described with respect to the embodiments shown in fig. 14 and 15, as well as any other embodiments described herein, are exemplary operations and/or components. In some embodiments, some operations and/or components may be omitted, and/or other operations and/or components may be included. Furthermore, in some embodiments, the temporal and/or spatial order of operations and/or components may be changed.

The present disclosure includes many inventive principles relating to association and authentication of multiple access point coordination. These principles may have independent utility and may be implemented separately and not every embodiment may utilize every principle. Furthermore, these principles may also be embodied in various combinations, some of which may amplify the benefits of the various principles in a coordinated manner.

The examples disclosed above have been described in the context of various implementation details, but the principles of the present disclosure are not limited to these or any other specific details. For example, certain functions have been described as being performed by certain components, but in other embodiments the functions may be distributed among different systems and components located in different locations and having different user interfaces. Certain embodiments have been described as having particular processes, steps, etc., but these terms also encompass embodiments in which particular processes, steps, etc. can be implemented with multiple processes, steps, etc., or multiple processes, steps, etc. can be integrated into a single process, step, etc. References to a component or element may refer to only a portion of that component or element.

Terms such as "first" and "second" are used in the present disclosure and claims only to distinguish matters modified by them, and may not indicate any spatial or temporal order unless it is apparent from the context. Mention of the first event may not suggest that a second event exists. Various ancillary organizational means, such as chapter titles, may be provided for convenience, but subject matter arranged in accordance with these ancillary means and the principles of the present disclosure is not limited by these ancillary organizational means.

The various details and embodiments described above may be combined to produce further embodiments in accordance with the inventive principles of this patent disclosure. Since the inventive principles of this patent disclosure may be modified in arrangement and detail without departing from the inventive concepts, such changes and modifications are considered to be within the scope of the appended claims.

Claims

1. A method of precompensating a transmitter in-phase I and quadrature Q mismatch IQMM, the method comprising:

transmitting the first signal through a transmission path to provide a second signal, wherein the second signal is an up-converted signal;

transmitting the second signal through an envelope detector;

determining one or more IQMM parameters of a transmit path based on the output of the envelope detector; and

determining one or more precompensation parameters for the transmit path based on the one or more IQMM parameters for the transmit path;

wherein determining one or more IQMM parameters of the transmit path comprises:

applying a first precompensation parameter to the transmit path;

determining a first power of a component of a second signal caused by transmitting an IQMM through the envelope detector based on the first precompensation parameter;

applying a second precompensation parameter to the transmit path;

Determining a second power of a component of a second signal caused by transmitting the IQMM through the envelope detector based on the second precompensation parameter; and

one of the first precompensation parameter or the second precompensation parameter is selected based on the lower of the first power and the second power.

2. The method according to claim 1, wherein:

the method further comprises the steps of:

applying one or more additional precompensation parameters to the transmit path; and

determining one or more additional powers of one or more components of the second signal caused by sending the IQMM through the envelope detector based on the one or more additional pre-compensation parameters; and

determining one or more IQMM parameters of the transmit path comprises: one of the first precompensation parameter, the second precompensation parameter or the one or more additional precompensation parameters is selected based on a lower of the first power, the second power or the one or more additional powers.

3. A method of precompensating a transmitter in-phase I and quadrature Q mismatch IQMM, the method comprising:

Transmitting the second signal through an envelope detector;

determining one or more IQMM parameters of a transmit path based on the output of the envelope detector;

wherein determining one or more IQMM parameters of the transmit path comprises:

applying a first precompensation parameter to the transmit path;

applying a second precompensation parameter to the transmit path; and

determining a second power of a component of a second signal caused by transmitting the IQMM through the envelope detector based on the second precompensation parameter;

the method further comprises the steps of:

scanning the frequency of the first signal transmitted through the transmit path to provide one or more additional second signals;

transmitting one or more additional second signals through the envelope detector to provide one or more additional outputs of the envelope detector; and

the one or more IQMM parameters of the transmit path are determined based on one or more additional outputs of the envelope detector.

4. A method of precompensating a transmitter in-phase I and quadrature Q mismatch IQMM, the method comprising:

transmitting a first input signal at a first frequency through a transmit path to provide a first output signal, wherein the first output signal is an upconverted signal;

transmitting a second input signal at a second frequency through the transmit path to provide a second output signal, wherein the second output signal is an upconverted signal;

transmitting the first output signal through an envelope detector to provide a first output of the envelope detector;

transmitting the second output signal through an envelope detector to provide a second output of the envelope detector;

determining one or more IQMM parameters of the transmit path based on the first output of the envelope detector and the second output of the envelope detector; and

one or more precompensation parameters of the transmit path are determined based on the one or more IQMM parameters of the transmit path.

5. The method of claim 4, further comprising:

the first pre-compensation parameter and the second pre-compensation parameter are applied to a transmit path of each of the first input signal and the second input signal.

6. The method according to claim 5, wherein:

Determining one or more IQMM parameters of the transmit path comprises: solving a system of equations based on the first output signal and the second output signal; and

a first equation in the equation includes a function of at least a portion of the first precompensation parameter and the second precompensation parameter.

7. The method of claim 5, wherein the second frequency is the first frequency negative at baseband.

8. The method of claim 5, further comprising:

scanning the first frequency and the second frequency for each of the first precompensation parameters and the second precompensation parameters;

determining additional first and second output signals based on scanning the first and second frequencies; and

one or more IQMM parameters of the transmit path over the frequency are determined based on the determined additional first output signal and the second output signal.