CN113676433A

CN113676433A - Method and apparatus for transmitting IQ mismatch calibration

Info

Publication number: CN113676433A
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: 2021-11-19
Anticipated expiration: 2041-05-14
Also published as: CN113676433B; KR20210141347A

Abstract

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

Description

Method and apparatus for transmitting IQ mismatch calibration

Cross Reference to Related Applications

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

Technical Field

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

Background

The quadrature transmitter may include an in-phase (I) path and a quadrature (Q) path. Imbalance between the I path and the Q path, which may be referred to as IQ mismatch (IQMM), may degrade 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) mismatches (IQMM), the method may comprise: transmitting a signal through an upconverter of a transmit path to provide an upconverted signal; determining an up-converted signal passing through a down-converter of a receive feedback path; determining one or more IQMM parameters for the transmit path based on the determined upconverted signal; and determining one or more pre-compensation 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 the equations may comprise a first component of the upconverted signal and a first parameter at least partially representative of an expected frequency response of the transmit path, and a second equation of the equations may comprise a second component of the upconverted signal and a second parameter at least partially representative of a frequency response of the transmit path due to transmitting IQMM. The first one of the equations may further comprise a third parameter representing, at least in part, 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 upconverted signal may include processing the upconverted signal to compensate for the iqm in the receive path. The local oscillator used for the transmit path may be frequency shifted relative to the local oscillator used for the receive feedback path. The signal may comprise a first signal at a first frequency, the upconverted signal may comprise a first upconverted signal, and the method may further comprise: the method may include sending 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) mismatches (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 pre-compensation parameters of the transmit path based on the one or more IQMM parameters of the transmit path. Determining one or more IQMM parameters for a transmit path may comprise: applying a first pre-compensation parameter to the transmit path; determining a first power of a component of the upconverted signal caused by sending an IQMM through the envelope detector based on the first pre-compensation parameter; applying a second pre-compensation parameter to the transmit path; and determining a second power of a component of the upconverted signal caused by sending the IQMM through an 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 pre-compensation parameter or the second pre-compensation parameter based on a lower of the first power and the second power. The method may further comprise: applying one or more additional pre-compensation parameters to the transmit path; and determining one or more additional powers of one or more components of the upconverted signal caused by sending an 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 may comprise selecting one of the first pre-compensation parameter, the second pre-compensation parameter, or one or more additional pre-compensation parameters based on a lower of the first power, the second power, or one or more additional powers. The signal may comprise a first signal at a first frequency, the upconverted signal may comprise a first upconverted signal, and the method may further comprise: sending 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 the envelope detector, and determining one or more iqm parameters of the transmit path based on the determined second upconverted signal. The method may further include applying first and second pre-compensation parameters 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 pre-compensation parameters, respectively. Determining one or more IQMM parameters of the transmit path may include solving the system of equations based on the determined first upconverted signal and second upconverted signal. The first equation in the system of equations may include a function of at least a portion of the first pre-compensation parameter and the second pre-compensation parameter. The second frequency may be a negative of the first frequency at baseband. The method may further comprise: scanning the first and second frequencies for each of the first and second pre-compensation parameters; determining additional first and second upconverted signals based on scanning the first and second frequencies; and determining one or more IQMM parameters of the transmit path in frequency based on the determined additional upconverted signal. The signal may comprise a first dual tone signal, the upconverted signal may comprise a first upconverted dual tone signal, and the method may further comprise transmitting a second dual tone signal through the upconverter of the transmit path to provide a second upconverted dual tone signal, determining a second upconverted dual tone signal through the envelope detector, and determining one or more iqm parameters of the transmit path based on the determined second upconverted dual tone signal. Determining one or more IQMM parameters of the transmit path may include solving a system of equations based on the determined first and second upconverted biphone signals, and at least one of the equations may include a first parameter for a first frequency of the first biphone signal and a second parameter for a second frequency of the first biphone 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 upconverted diphone signals based on scanning the first and second frequencies; and determining one or more IQMM parameters for the transmit path based on the determined additional upconverted dual-tone signal.

A system may include: an IQ transmit path comprising an upconverter; an envelope detector arranged to provide an envelope of the upconverted 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 upconverted 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 upconverted signal passing through a branch of an IQ receiver.

A system may include: an IQ transmit path comprising an upconverter; 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 upconverted 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 upconverted signal, and one or more compensation coefficients of the IQ transmit path are estimated based on the estimated IQMM parameters.

Drawings

The figures are not necessarily to scale and elements of similar structures or functions are generally represented by like reference numerals throughout the figures for illustrative purposes. The drawings are intended to facilitate the description of the embodiments disclosed herein only. The drawings do not depict every aspect of the teachings disclosed herein and do not limit the scope of the claims. The drawings illustrate exemplary embodiments of the 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 techniques in accordance with the present disclosure.

Fig. 2 illustrates an exemplary embodiment of a complex-valued precompensator (CVC) structure whose coefficients may 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 in accordance with 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 shows an exemplary embodiment of a spectral plot 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 spectral plots of the transmitted and captured (monitored) signal using a first embodiment of the method for TX IQMM calibration using an envelope detector according to the present invention.

Fig. 9 shows some spectral plots of the transmitted and captured (monitored) signal using a third embodiment of the method for 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 according to 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 a number of inventive principles relating to pre-compensating for in-phase (I) and quadrature (Q) mismatches (IQMM) in a quadrature upconversion transmitter. Pilot signals may be applied to the Transmit (TX) path at baseband and various disclosed techniques and algorithms may be used to capture and process the IQMM corrupted upconverted signal to estimate the 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 the coefficients of the pre-compensator in the TX path.

In some embodiments, the iqm-impaired upconverted signal may be captured through a Receive (RX) feedback path with a quadrature downconverter. The tone pilot signals may be applied at different frequencies and the primary and image components of the captured down-converted signal may be used in a system of equations 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 using a frequency shift between the local oscillators of the TX and RX paths.

In some embodiments, the iqm corrupted upconverted signal may be captured by an envelope detector and processed using various disclosed techniques. In a first method using an envelope detector, the monophonic pilot signal may be applied while varying one or more pre-compensation parameters. 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 with a component twice the frequency of the pilot signal. Thus, the first method may scan one or more pre-compensation parameters while applying the first 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 for the TX path.

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

In a third approach using an envelope detector, various combinations of negative and positive frequencies of the two-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 obtain directly an estimate of the TX IQMM parameters.

Once the TX IQMM parameters are determined by any of these disclosed techniques, they may be used to determine the coefficients of the pre-compensator 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. Moreover, these principles can also be embodied in various combinations, some of which can amplify the benefits of each principle in a synergistic manner.

TX precompensation

In a quadrature upconversion transmitter, the IQMM between the I branch and the Q branch may cause interference after upconversion to an image frequency at a Radio Frequency (RF) or Intermediate Frequency (IF). Therefore, IQMM may degrade system performance by reducing the effective signal-to-interference-plus-noise ratio (SINR). The frequency independent iqm (FI-iqm) may result from the imbalance of the mixer, while the frequency dependent iqm (FD-iqm) may be caused by a mismatch between the overall frequency response on the I and Q paths. In some embodiments, only frequency independent IQMM (FI-IQMM) may be compensated. However, in certain applications, such as broadband systems (e.g., millimeter wave systems), FI-IQMM compensation alone may not provide sufficient performance. Accordingly, some inventive principles of this application relate to techniques for providing FD-IQMM compensation for a quadrature upconverter transmitter. In addition, TX IQMM may be different from 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 techniques in accordance with 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(t) low pass filter 108 and mixer 112. Transmitter 100, which may also be referred to as a TX path, may also include a Q signal path including DAC 106 with an impulse response h_QTX Low pass filter 110 and mixer 114 of (t). The

mixers

112, 114 and the

filters

108, 110 and the summing circuit 116 may together form an up-converter. The transmitter 100 may further include an iqm precompensator 118.

In the transmitter, g_TXNot equal to 1 and phi_TXNot equal to 0 may respectively indicate that transmission is possibleThe TX gain and phase mismatch, which produces a frequency independent IQ mismatch (FI-IQMM), at the processor. Overall frequency response h in the I and Q paths of the TX path_ITX(t) and h_QTXMismatch between (t) may generate FD-IQMM, i.e., h, in the TX path_ITX(t)≠h_QTX(t) of (d). The baseband equivalent of the upconverted signal in the Tx path 100 (at the output of the mixer) in the frequency domain can be expressed as:

Z_TX(f)＝G_1TX(f)U(f)+G_2TX(f)U^*(-f), 1)

where U (f) may be the frequency response of the desired baseband (BB) signal at the input 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) can be represented separately_ITX(t)) and a filter 110 (h)_QTX(t)) frequency response. In equation (1), G_1TX(f) U (f) may represent an expected TX signal, and G_2TX(f)U^*The (-f) may represent a TX image signal. If there is not any IQMM, (g)_TX＝1、φ _TX0 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) May represent the expected frequency response of the transmit path, and G_2TX(f) The frequency response of the transmission path due to the IQMM can 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 the IQMM in the transmitter 100.

The one or more IQMM parameters may include any parameter affected by IQMM in the TX path, such as gain mismatch g_TXPhase mismatch phi_TXFilter 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_TXAnd V_TX(f) May be used as IQMM parameters because, for example, they may reduce the complexity and/or effort involved in the 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) May be used as the IQMM parameter which may be estimated and then used to determine the pre-compensation parameter.

The pre-compensation parameter may be any parameter that may determine how IQMM pre-compensator 118 affects IQMM in TX path 100. An example of a pre-compensation parameter may be the coefficients of IQMM pre-compensator 118 (IQMC coefficients), which may be for BB signal s [ n [ ])]＝s_j[n]+js_Q[n]Shaping to reduce or eliminate the upconverted signal z_TXImage component in (t). An example of IQMC coefficients that may be obtained based on the estimated IQMM parameters will be described below.

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

The continuous-time frequency f ═ f can be estimated using various calibration algorithms described herein₁,...,±f_KPhase mismatch in the desired frequency band_TXAnd V_TX(f) In that respect Then, phi may be used_TXAnd V_TX(f) To obtain IQ mismatch compensator (IQMC) coefficients of the pre-compensator 118 to reduce TX FD-IQMM.

FIG. 2 illustrates a complex-valued precompensator whose coefficients may be estimated according to the present disclosureExemplary embodiments of (CVC) structures. The embodiment shown in FIG. 2 may include having a delay T_DInteger delay element 200, complex conjugate block 202, having an impulse response w_TX[n]A complex-valued filter 204 and an adder 206.

Then, the coefficient values of the pre-compensator shown in fig. 2 may be expressed as follows, wherein the coefficient values may completely or partially remove the TX FD-IQMM of the transmitter 100 shown in fig. 1:

wherein

Representation filter w_TX[n]The frequency response of (c). It is apparent from equation (4) that the best response of the IQMC coefficients may involve phi_TXAnd/or V_TX(f) May be estimated, for example, using any of the techniques disclosed herein.

In some embodiments, and depending on implementation details, the methods, expressions, etc. disclosed herein may provide optimal values, and thus may use the indicator "opt". However, the present principles are not limited to embodiments in which the optimum values can be obtained, and the use of "optimum" or "optimal" is not limited to methods, expressions, or the like that can provide the optimum values.

Some exemplary embodiments of the CVC structure shown in fig. 2 may include any of the following embodiment details. Having an impulse response w_TX[n]The complex-valued filter 204 may be implemented as, for example, 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 a delay T_DThe integer delay element 200 may be configured to generate 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 illustrating the inventive principles of the present disclosure, but other iqm pre-compensation structures and/or combinations thereof may be used. For example, in some embodiments, a real-valued 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 in accordance with 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 precompensator 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 means, such as switches, couplers, conductors, transmission lines, filters, and the like. Feedback connection 304 may be coupled to TX path 300 at any location after up-converter 314. The feedback connection 304 may be coupled to the RX path 302 at any location before the downconverter 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 so forth. RF receive block 318 may include various components for receiving RF signals, such as an antenna, a band pass filter, a Low Noise Amplifier (LNA), and so on. The iqm in TX path 300 may be corrected by iqm 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 upconverted pilot signal via RX path 302, performing computations and/or offloading computations on other resources, providing estimated coefficients to TX precompensator 308, controlling TX precompensator 308 during transmission and/or transmission of the pilot signal, 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. Also, individual components and/or their functions may be distributed among other components 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 function by 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 a hardware implementation 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 a portion of the software implementations may include one or more processor cores, memory, program and/or data memories, and/or the like, which may be located locally and/or remotely, and which 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. The TX path 400, similar to the transmitter 100 shown in fig. 1, may include an I signal path including a DAC 404 having an impulse response h_ITX(t) low pass filter 408 and mixer 412. TX path 400 can also include a Q signal path comprising DAC 406, having impulse response h_QTX(t) low pass filter 410 and mixer 414. The

mixers

412 and 414, the

filters

408 and 410, and the summing circuit 416 may collectively form an upconverter. TX path 400 may further include iqm precompensator 418.

RX path 402 may include an I signal path including a mixer 426 having an impulse response h_IRX Low pass filter 430 of (t), and ADC 434. The RX path 402 may also include a Q signal path including a mixer 428 having an impulse response h_QRX Low pass filter 432 of (t), and ADC 436. The

mixers

426 and 428 and the

filters

430 and 432 may collectively form a down-converter. In some embodiments, RX path 402 may further include an iqm compensator (not shown), which may be disabled or placed in a pass-through state during calibration operations.

In some embodiments, during the calibration operation, IQMM precompensator 418 may be disabled or placed in pass-through mode such that IQMC may be unitary, thus u (f) s (f).

For estimating the IQMM parameter phi_TXAnd V_TX(f) The monophonic signal may be at frequency f_kApplied down the baseband of TX path 400, i.e., u (f) ═ a_TXδ(f-f_k) Wherein A is_TXMay 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-impaired upconverted signal may be amplified at the primary frequency and the image frequency (f) by capturing the downconverted signal through the RX feedback path_kand-f_k) The frequency response of the measured frequency is monitored and can be expressed as

And

next, at frequency-f, may be passed through TX path 400_kSending monophonic signals, i.e.

And frequency-f_kAnd f_kThe down-converted signals may be denoted as R_3,k＝R′(-f_k) And R_4,k＝R′(f_k). Collecting all measurements can provide the following set of equations

Wherein A is_RXMay represent the gain and/or delay from RX ABB filters 430 and 432 to RX BB. 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 spectral plot of a transmitted and captured (observed) signal corresponding to equation (5).

A single tone signal (e.g., f) may be targeted for all selected frequency pairs over the entire channel band_k) A frequency sweep is performed to obtain φ using equation (5)_TXAnd V_TX(f) Is estimated as follows

Wherein

In some embodiments of the calibration algorithm described above, the IQMM at the RX feedback path may be assumed to be zero. In some other embodiments, the RX feedback path may also introduce RX IQMM into the observations, which may in turn reduce the estimation accuracy 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 observed values of the upconverted pilot signal, in accordance with the present disclosure.

In a first technique according to the present disclosure, separate Local Oscillators (LOs) of TX and RX paths may be used to calibrate RX in loopback modeFD-IQMC (e.g., sweep the TX LO and use the DC tone at BB of the TX path while keeping the RX LO unchanged). Next, the BB TX tone may be swept across the frequency to fix both the TX LO and RX LO at the same frequency. The TX FD-IQMC coefficients may then be determined. In some embodiments, additional steps may be added to post-process the received signal r (f) to estimate phi_TXAnd V_TX(f) The effect of RX-IQMM was previously removed.

In a second technique according to the present disclosure, a frequency shift may be created between the LO of the TX path and 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 the 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 constructed and/or operated in a manner similar to that shown in fig. 3. In particular, TX path 600 may include a precompensator 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 capturing 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. An envelope detector 640, which may be implemented using any suitable means including diodes, filters, etc., may be coupled to the TX path 600 at any location after the upconverter 614. The return signal path 642 may include any suitable devices, such as switches, couplers, conductors, transmission lines, filters, data converters, and the like.

In some embodiments, the envelope detector 640 may provide a circuit having a length of non-conducting filament, e.g., y (t) ═ z (t)²An output in the form of (1). In some embodiments, some or all of the envelope detector 640 may be integrated with the or TX path 600.

In some embodiments, the envelope detector 640 may output the envelope of the iqm corrupted upconverted signal and feed it back to the signal processing unit 606 without passing 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 embodiments, 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 a transceiver system where an RX path already exists.

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.

The TX path 700, which may be similar to the TX path 400 shown in fig. 4, may include an I signal path including a DAC 704 having an impulse response h_ITX(t) low pass filter 708, and mixer 712. The TX path 700 may also include a Q signal path including a DAC 706 having an impulse response h_QTX(t) low pass filter 710, and mixer 714. The

mixers

712 and 714,

filters

708 and 710, and summing circuit 716 may collectively form an upconverter. TX path 700 may further include iqm precompensator 718.

The RX path 702, which may be similar to the RX path 402 shown in fig. 4, may include an I signal path including a mixer 726, having an impulse response h_IRX Low pass filter 730 of (t), and ADC 734. The RX path 702 may also include a Q signal path including a mixer 728, having an impulse response h_QRX Low pass filter 732 and ADC 736 of (t).

Mixers

726 and 728 and

filters

730 and 732 may collectively form a downconverter. In some embodiments, RX path 702 may further include an iqm 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 location 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.

Embodiments of three different methods of estimating the TX IQMM using an envelope detector are 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 embodiment details.

Method 1

In some embodiments, the method may seek to obtain a frequency that may be ± f₁,...,±f_KSingle-tap (single-tap) precompensator filter coefficients to cancel IQMM down. These coefficients can then be used to estimate the IQMM parameter phi_TXAnd V_TX(f)。

Referring to fig. 8, in some embodiments, if there is any IQMM in the TX link, the frequency-f sent at baseband_kMay be generated at the envelope detector with a frequency 2f_kThe output of the component (b). Thus, it can be at frequency-f_kThe single tone signal is then transmitted from the TX baseband, the precompensator coefficients are swept (in some embodiments one such tap is sufficient), and the coefficient that provides the lowest power at the envelope detector output at twice the frequency of the BB signal, i.e., 2f, is selected_kTo thereby find the frequency f_kThe (in some embodiments, the best or optimal) coefficients of the single tap precompensator. For at frequency-f_kFor the transmitted mono signal, the output of the envelope detector path may be denoted as r (t), and its response (ignoring high frequency components) may be denoted as:

envelope detector output at frequency 2f_kThe frequency response of (d) can be expressed as

Without IQMM, G_2TX(f_k) Possibly zero, and therefore R (2 f) in equation (9)_k) Possibly zero. By performing a search of the precompensator coefficients, a single-tap precompensator setting, i.e. w, can be obtained_TX[n]＝w_TX,0×δ[n]Such that R (2 f)_k) Can become zero and cancel the frequency f_kIQMM of the following. To f_kScanning and obtaining for T _D0 is composed of

After the IQMC coefficients (e.g., the best coefficients) on all frequency tones are represented, phi_TXAnd 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 an extensive or exhaustive search. For example, the search may be conducted at fixed intervals over a wide range of pre-compensator settings and/or frequency tones. In some embodiments, the search may be performed in stages. For example, the initial search may be conducted over a wide interval, over a wide range with a coarser pre-compensator setting and/or frequency tone grid. One or more additional searches may then be performed on the finer grid at smaller intervals within one or more smaller ranges based on the results of the coarse search.

Method 2

In some embodiments, the method may directly estimate the given frequency f_kThe IQMM parameter at f, e.g. by using two different precompensator coefficients and/or setting at f_kAnd-f_kThe tone signal is transmitted separately. These measurements can then be taken at frequency 2f using, for example, a quadratic equation in closed form_kThe lower envelope detector outputs are combined and solved to obtain f_kThe following frequency dependent gain and phase mismatch.Then, the IQMM parameter φ can be found_TXAnd V_TX(f) E.g. as per frequency f_kIs 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_kAnd-f_kCan be applied to the TX path alone at BB without any IQMC, e.g., w_TX[n]0 and the envelope detector output is at frequency 2f_kThe lower frequency response may be represented as Y_1,kAnd Y_2,k. Another set of T-devices may be selected and applied_DPre-compensation parameter w [ n ] of 0 delay element]And can transmit a frequency f_kThe single tone signal of (a). The envelope detector output is at frequency 2f_kThe frequency response of (d) may be represented as Y_3,k. This gives the following equation

Wherein J₁And J₂May be a known value and may be defined as follows

J₁＝1,

Can use the relationship

And equations (2) and (3) reformulate equation (11) as

Wherein

Fang ChengEquation (13) may provide six real equations with five real unknowns, namely Re { γ }, Im { γ }, Re { V }, and_TX(f_k)},Im{V_TX(f_k)},φ_TXwherein these equations can be solved to obtain V_TX(f_k) And phi_TXAn estimate of (d). The IQMM parameter V may be expressed_TX(-f_k) Estimated as

This parameter may follow h_ITX(t) and h_QTX(t) is a real-valued filter, which may be conjugate symmetric in the frequency domain, i.e.

And

method 3

In some embodiments, the method may involve separately counting frequencies

And

a two-tone pilot signal is transmitted. It is then possible to use, for example, two quadratic equations in closed form at frequency

These measurements are then combined and solved by the envelope detector output to obtain phi directly_TXAnd V_TX(f) In that

The following estimated values.

Referring to fig. 9, in some embodiments of this method, frequencies may be generated and transmitted at TX baseband

Of two tones, i.e.

And the time domain signal can be captured at the output of the envelope detector. The frequency response of the time domain signal may be expressed as

Next, the frequency may be set

And

down transmitting polyphonic signals, i.e.

And the envelope detector output is at frequency

The frequency response of

And

the multi-tone signal may then be in frequency

And

is sent down, i.e.

And the captured envelope signal is in frequency

The frequency response of

And

the following parameters may be defined:

combining all observations, the following non-linear equation can be provided:

for example, the set of 8 equations with 8 unknowns in equation (15) can 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_k＝argmax_i(|β_2,iL) and

C.

and

can be calculated as

D.

And

can be calculated as

2. In obtaining all

And

thereafter, wherein

a.φ_TXCan be estimated as

b.V_TX(f) Can be obtained in the following manner

For a case where r is 1,2,

in some embodiments, f_k1>0 and

can be selected such that the frequency is

May be different.

The selection of the two-tone pilot signal (and its positive and negative frequencies) and the resulting envelope detector output signal selected for analysis purposes is for illustration purposes only, and 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 use

And

to 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 two-tone pilot signal, pilot signals having any number of tones may be used, e.g., three tones, four tones, 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 a two-tone signal. In contrast, in some embodiments using method 2, each equation may include only a single frequency iqm. Thus, in some embodiments, and depending on implementation details, different methods may be used to obtain different sets of equations.

Obtaining IQMC coefficients

In some embodiments, when f is ± f₁,...,±f_KObtaining phi_TXAnd V_TX(f) These estimates may then 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_DMay be at a frequency f ═ f₁，...,±f_KEstimating the parameters given in equation (4) below

For example, in a Finite Impulse Response (FIR) filter having a length L

In the embodiment, the method can obtain the optimal l tap filter

The filter can minimize W_TX(f) And

at a frequency f ═ f₁,...,±f_KLeast Squares (LS) error of the following, as follows

Wherein

And F ═ F₀,...,F_L-1]Is a Discrete Fourier Transform (DFT) matrix of size 2K × L. In some embodiments, T_DThe values in 0, 1, L-1 may be taken. For a fixed T_D，w_TXCan be found as

Has the advantages of

The least square error of (d). Then, the optimum T_DAnd filter coefficients

May be represented by the following formula:

although some techniques have been described in the context of a precompensator architecture such as that 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 architectures. Further, the filter coefficients of the IQMC structure may be obtained based on the estimated IQMM parameters using techniques other than LS, and the method described herein is merely an example 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 illustrated 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 counter k. If K is less than or equal to the maximum value K, the method may proceed to operation 1006, where it may be at frequency f_kA tone pilot signal is generated and applied to the TX path 400 at the baseband. In operation 1008, the received pilot signal may be at frequency f at baseband of RX path 402_kAnd-f_kAre captured below and are respectively represented as R_1,kAnd R_2,k. In operation 1010, the frequency may be at frequency-f_kA tone pilot signal is generated and applied to the TX path 400 at baseband. In operation 1012, the received pilot signal may be at frequency-f at baseband of the RX path 402_kAnd f_kAre captured below and are respectively represented as R_3,kAnd R_4,k。

In operation 1014, the method may increment the value of counter k and return to operation 1004 where the method may check the value of counter k. If K is greater than the maximum value K, the method can proceed to operation 1016 where the pair R is used_1,k,…,R_4,kObserved value of (2)

The method may estimate the IQMM parameter phi_TXAnd V_TX(f),f＝±f₁,...,±f_K. In operation 1018, the method may use phi_TXAnd V_TX(f),f＝±f₁,...,±f_KTo estimate the coefficients of TX IQMM precompensator 418. The method may then end at operation 1020.

As described above, in some embodiments, R may be obtained, for example, by capturing the time domain signal at BB of RX path 402 and converting it to a frequency domain signal using, for example, an FFT_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 counter k. If K is less than or equal to the maximum value K, the method may proceed to operation 1106, where a new precompensator setting may be selected from the possible precompensator values. In operation 1108, the frequency may be at f_kA tone pilot signal is generated and applied to the TX path 700 at baseband. In operation 1110, the output of the ABB filter in the envelope detector path may be captured at a frequency 2f_kDown 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 adjusted_kThe optimum value of the precompensator setting is set to the current setting. In operation 1116, the method may be directed to_kThe process is repeated for the next generated tone signal.

In operation 1118, the method may increment the value of counter k and return to operation 1104 where the 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 the values for f are used₁,…,±f_kCan estimate the IQMM parameter phi_TXAnd V_TX(f),f＝±f₁,...,±f_K. In operation 1122, the method may use phi_TXAnd V_TX(f),f＝±f₁,...,±f_KTo estimate the coefficients of TX IQMM precompensator 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 illustrated 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 counter k. If K is less than or equal to the maximum value K, the method may proceed to operation 1206, where a first precompensator setting, for example, without IQMC may be selected. In operation 1208, the method may be at frequency f at BB of transmit path 700_kA monophonic signal is generated and transmitted. The signal at the output of the ABB filters 730 and 732 in the envelope detector path may be at frequency 2f_kLower is captured and denoted as Y_1,k. In some embodiments, the signals may be captured after the

ADCs

734 and 736. In operation 1210, the method may be at frequency-f at BB of the transmit path 700_kGenerating and transmitting monophonic signals. The signal at the output of the ABB filters 730 and 732 in the envelope detector path may be at frequency 2f_kLower is captured and denoted as Y_2,k. At operation 1212, the method may select a second precompensator setting to apply to the TX path 700. In operation 1214, the method may be at frequency f at BB of transmit path 700_kA monophonic signal is generated and transmitted. The signal at the output of the ABB filters 730 and 732 in the envelope detector path may be at frequency 2f_kLower is captured and denoted as Y_3,k。

In operation 1216, the method may increment the value of counter k and return to operation 1204, where the method may check 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,kAnd Y_3,kFor each k, the method can estimate the IQMM parameter φ_TXAnd V_TX(f),f＝±f₁,...,±f_K. In operation 1220, the method may use φ_TXAnd V_TX(f),f＝±f₁,...,±f_KTo estimate the coefficients of TX IQMM precompensator 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 illustrated 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 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 the baseband of the TX path 700

And then generates and transmits the dual tone signal. In operation 1308, the signal at the output of the ABB filters 730 and 732 in the envelope detector path may be at frequency

The lower is captured and represented as Y, respectively_1,k、Y_2,k、Y_3,k、Y_4,k. In operation 1310, a frequency may be at baseband of TX path 700

The two-tone signal is generated and transmitted. In operation 1312, the signal at the output of ABB filters 730 and 732 in the envelope detector path may be at frequency

Lower capture, and are respectively denoted as Y_5,k、Y_6,k. In operation 1314, the frequency may be at baseband of the TX path 700

The two-tone signal is generated and transmitted. In operation 1316, the signals at the outputs of the ABB filters 730 and 732 in the envelope detector path may be at frequency

Lower capture, and are respectively 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 check 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,kFor each k, the method can estimate the IQMM parameter φ_TXAnd V_TX(f),f＝±f₁,...,±f_K. In operation 1322, the method may use phi_TXAnd V_TX(f),f＝±f₁,...,±f_KTo estimate the coefficients of TX IQMM precompensator 718. The method may then end at operation 1324.

Fig. 14 illustrates an embodiment of a method for pre-compensating a transceiver IQMM according to the present disclosure. The method may begin at operation 1400. In operation 1402, the method may send a signal through an upconverter of a transmit path to provide an upconverted signal. In operation 1404, the method can 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 transmission path based on the determined upconverted signal, and in operation 1408, the method may determine one or more pre-compensation parameters of the transmission path based on the one or more IQMM parameters of the transmission 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 can send a signal through an upconverter of a transmit path to provide an upconverted signal. In operation 1504, the method may determine an upconverted 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 upconverted signal, and in operation 1508, the method may determine one or more pre-compensation 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. Moreover, in some embodiments, the temporal and/or spatial order of the operations and/or components may be changed.

The present disclosure includes a number of inventive principles relating to multi-access point coordinated association and authentication. These principles may have independent utility and may be implemented separately, and not every embodiment may utilize every principle. Moreover, these principles can also be embodied in various combinations, some of which can amplify the benefits of each principle in a synergistic manner.

The above disclosed examples have been described in the context of various implementation details, but the principles of the disclosure are not limited to these or any other specific details. For example, some functionality has been described as being carried out by certain components, but in other embodiments, the functionality 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 a particular process, step, etc., may be implemented using multiple processes, steps, etc., or multiple processes, steps, etc., may be integrated into a single process, step, etc. A reference 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 merely to distinguish what they modify and may not indicate any spatial or temporal order unless apparent from the context. Reference to the first event may not imply that the second event exists. Various auxiliary organizing means such as chapter titles may be provided for convenience, but the subject matter arranged in accordance with these auxiliary organizing means and the principles of the present disclosure is not limited by these auxiliary organizing means.

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 pre-compensating a transmitter in-phase (I) and quadrature (Q) mismatch IQMM, the method comprising:

sending a signal through an upconverter of a transmit path to provide an upconverted signal;

determining the upconverted signal through a downconverter of a receive feedback path;

determining one or more IQMM parameters for the transmit path based on the determined upconverted signal; and

determining one or more pre-compensation parameters for the transmit path based on the one or more IQMM parameters for the transmit path.

2. The method of claim 1, wherein:

determining one or more IQMM parameters of the transmit path comprises solving a system of equations;

a first one of the equations comprises a first component of the upconverted signal and a first parameter at least partially representative of an expected frequency response of the transmit path; and

a second one of the equations includes a second component of the upconverted signal and a second parameter at least partially representative of a frequency response of the transmit path due to transmitting IQMM.

3. The method of claim 2, wherein the first one of the equations further comprises a third parameter that is at least partially representative of a gain and a delay of the transmit path.

4. The method of claim 1, wherein:

the method further includes determining an iqm 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 upconverted signal comprises: processing the upconverted signal to compensate for the IQMM in the receive path.

5. The method of claim 1, wherein a local oscillator for the transmit path has a frequency shift relative to a local oscillator for the receive feedback path.

6. The method of claim 1, wherein the signal comprises a first signal at a first frequency, the upconverted signal comprises a first upconverted signal, and the method further comprises:

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 by the downconverter of the receive feedback path; and

determining one or more IQMM parameters for the transmit path based on the determined second upconverted signal.

7. The method of claim 1, further comprising:

scanning a frequency of the signal transmitted through the upconverter of the transmit path to provide an additional upconverted signal;

determining the additional upconverted signal by the downconverter of the receive feedback path; and

determining the one or more IQMM parameters for the transmit path based on the determined additional upconverted signal.

8. A method of pre-compensating a transmitter in-phase (I) and quadrature (Q) mismatch IQMM, the method comprising:

determining the up-converted signal passing through an envelope detector;

9. The method of claim 8, wherein determining one or more IQMM parameters of the transmit path comprises:

applying a first pre-compensation parameter to the transmit path;

determining a first power of a component of the upconverted signal caused by sending an IQMM through the envelope detector based on the first pre-compensation parameter;

applying a second pre-compensation parameter to the transmit path; and

determining a second power of a component of the upconverted signal caused by sending an IQMM through the envelope detector based on the second pre-compensation parameter.

10. The method of claim 9, wherein determining one or more IQMM parameters for the transmit path further comprises selecting one of the first pre-compensation parameter or the second pre-compensation parameter based on a lower of the first power and the second power.

11. The method of claim 10, wherein:

the method further comprises the following steps:

applying one or more additional pre-compensation parameters to the transmit path; and

determining one or more additional powers of one or more components of the upconverted signal caused by sending an 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: selecting one of the first pre-compensation parameter, the second pre-compensation parameter, or the one or more additional pre-compensation parameters based on a lower of the first power, the second power, or the one or more additional powers.

12. The method of claim 9, further comprising:

determining the additional up-converted signal by the envelope detector; and

13. The method of claim 8, wherein the signal comprises a first signal at a first frequency, the upconverted signal comprises a first upconverted signal, and the method further comprises:

determining the second up-converted signal by the envelope detector; and

14. The method of claim 13, wherein:

the method further comprises applying the first and second pre-compensation parameters to the transmit path for each of the first and second signals; and

the first upconverted signal and the second upconverted signal are determined based on the first pre-compensation parameter and the second pre-compensation parameter, respectively.

15. The method of claim 14, wherein:

determining one or more IQMM parameters of the transmit path comprises solving a system of equations based on the determined first upconverted signal and second upconverted signal; and

a first one of the equations comprises a function of at least part of the first and second pre-compensation parameters.

16. The method of claim 14, wherein the second frequency is the first frequency that is negative at baseband.

17. The method of claim 14, further comprising:

scanning the first frequency and the second frequency for each of the first pre-compensation parameter and the second pre-compensation parameter;

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

based on the determined additional upconverted signal, one or more IQMM parameters of the transmit path over the entire frequency are determined.

18. The method of claim 8, wherein the signal comprises a first biphone signal, the upconverted signal comprises a first upconverted biphone signal, and the method further comprises:

transmitting a second duotone signal through the upconverter of the transmit path to provide a second upconverted duotone signal;

determining the second up-converted two-tone signal passing through the envelope detector; and

determining one or more IQMM parameters for the transmit path based on the determined second upconverted two-tone signal.

19. The method of claim 18, wherein:

determining one or more IQMM parameters of the transmit path comprises: solving a system of equations based on the determined first and second upconverted diphone signals; and

at least one of the equations includes a first parameter for a first frequency of the first dual tone signal and a second parameter for a second frequency of the first dual tone signal.

20. The method of claim 18, further comprising:

scanning a first frequency and a second frequency of at least one of the two tone signals;

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

determining one or more IQMM parameters for the transmit path over the entire frequency based on the determined additional upconverted two-tone signal.

21. The method of claim 18, further comprising:

sending a third two-tone signal through the upconverter of the transmit path to provide a third upconverted two-tone signal;

determining the third up-converted two-tone signal passing through the envelope detector; and

determining one or more IQMM parameters for the transmit path based on the determined third upconverted diphone signal.

22. The method of claim 21, wherein the frequency of the two-tone signal comprises a combination of at least one positive tone and at least one negative tone at baseband.

23. A system, comprising:

an IQ transmit path comprising an upconverter;

an envelope detector arranged to provide an envelope of the upconverted signal from the IQ transmit path;

a signal generator arranged to apply a pilot signal to the IQ transmit path;

a signal monitor arranged to capture an 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 upconverted signal; and

estimating one or more compensation coefficients for the IQ transmit path based on the estimated IQMM parameters.

24. The system of claim 23, wherein the signal monitor is arranged to capture the envelope of the upconverted signal passing through a branch of an IQ receiver.