SHAKED RONEN (US)
EISTEIN YANIV (US)
WO2020019336A1 | 2020-01-30 |
US20210328837A1 | 2021-10-21 | |||
US20110249637A1 | 2011-10-13 |
CLAIMS What is claimed is: 1. A method for wireless communication at a user equipment (UE), comprising: receiving, via a downlink channel, a downlink message comprising an indication of a precoder applied to one or more downlink signals; receiving the one or more downlink signals using at least one demodulation reference signal and the precoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; performing an iterative channel estimation procedure to estimate the downlink channel; performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the precoder; and receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. 2. The method of claim 1, further comprising: performing the iterative channel estimation procedure to estimate a physical channel associated with the one or more downlink signals using the at least one demodulation reference signal; and estimating the estimated gain and phase mismatch based at least in part on the estimated physical channel, the precoder, or both. 3. The method of claim 1, wherein the indication of the precoder comprises one or more precoder coefficients, wherein receiving the one or more downlink signals further comprises: applying the one or more precoder coefficients to the one or more downlink signals. 4. The method of claim 1, wherein performing the iterative channel estimation procedure further comprises: performing a first channel estimation procedure; performing the gain and phase mismatch equalization procedure; and performing at least a second channel estimation procedure based at least in part on the estimated gain and phase mismatch. 5. The method of claim 1, wherein performing the gain and phase mismatch equalization procedure further comprises: cancelling at least a portion of the estimated gain and phase mismatch. 6. The method of claim 1, wherein receiving the downlink message comprising the indication of the precoder further comprises: receiving the indication of the precoder via a set of downlink precoded data, wherein one or more precoder coefficients are determined based at least in part on the set of downlink precoded data. 7. The method of claim 1, further comprising: performing the gain and phase mismatch equalization procedure and equalizing the estimated gain and phase mismatch of the one or more downlink signals simultaneously. 8. The method of claim 1, wherein receiving the one or more downlink signals further comprises: reproducing the one or more downlink signals to use for the gain and phase mismatch equalization procedure based at least in part on the at least one demodulation reference signal and the precoder. 9. The method of claim 1, wherein receiving the indication of the precoder further comprises: receiving an indication of a time duration, a slot number, or both, for which the precoder is applied to the one or more downlink signals. 10. The method of claim 1, wherein a value of the precoder comprises a static value or a pseudo-random value, the method further comprising: performing the gain and phase mismatch equalization procedure based at least in part on the value of the precoder. 11. The method of claim 1, wherein the indication of the precoder comprises a first indication of a first precoder, the method further comprising: receiving, via the first indication of the first precoder, a second indication of a second precoder to be applied to the one or more downlink signals after a threshold time duration; and performing the gain and phase mismatch equalization procedure in accordance with the second precoder. 12. The method of claim 1, further comprising: receiving, from a network entity, a periodicity indication that indicates a periodicity for which the UE is to perform the gain and phase mismatch equalization procedure based at least in part on one or more operating factors of the network entity. 13. The method of claim 1, wherein the gain and phase mismatch equalization procedure comprises an in-phase quadrature-phase mismatch equalization procedure. 14. The method of claim 1, wherein the estimated gain and phase mismatch is a frequency-dependent gain and phase mismatch. 15. An apparatus for wireless communication at a user equipment (UE), comprising: a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: receive, via a downlink channel, a downlink message comprising an indication of a precoder applied to one or more downlink signals; receive the one or more downlink signals using at least one demodulation reference signal and the precoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; perform an iterative channel estimation procedure to estimate the downlink channel; perform a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the precoder; and receive one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. 16. The apparatus of claim 15, wherein the instructions are further executable by the processor to cause the apparatus to: perform the iterative channel estimation procedure to estimate a physical channel associated with the one or more downlink signals using the at least one demodulation reference signal; and estimate the estimated gain and phase mismatch based at least in part on the estimated physical channel, the precoder, or both. 17. The apparatus of claim 15, wherein the indication of the precoder comprises one or more precoder coefficients, and the instructions to receive the one or more downlink signals are further executable by the processor to cause the apparatus to: apply the one or more precoder coefficients to the one or more downlink signals. 18. The apparatus of claim 15, wherein the instructions to perform the iterative channel estimation procedure are further executable by the processor to cause the apparatus to: perform a first channel estimation procedure; perform the gain and phase mismatch equalization procedure; and perform at least a second channel estimation procedure based at least in part on the estimated gain and phase mismatch. 19. The apparatus of claim 15, wherein the instructions to perform the gain and phase mismatch equalization procedure are further executable by the processor to cause the apparatus to: cancel at least a portion of the estimated gain and phase mismatch. 20. The apparatus of claim 15, wherein the instructions to receive the downlink message comprising the indication of the precoder are further executable by the processor to cause the apparatus to: receive the indication of the precoder via a set of downlink precoded data, wherein one or more precoder coefficients are determined based at least in part on the set of downlink precoded data. 21. The apparatus of claim 15, wherein the instructions are further executable by the processor to cause the apparatus to: perform the gain and phase mismatch equalization procedure and equalizing the estimated gain and phase mismatch of the one or more downlink signals simultaneously. 22. The apparatus of claim 15, wherein the instructions to receive the one or more downlink signals are further executable by the processor to cause the apparatus to: reproduce the one or more downlink signals to use for the gain and phase mismatch equalization procedure based at least in part on the at least one demodulation reference signal and the precoder. 23. The apparatus of claim 15, wherein the instructions to receive the indication of the precoder are further executable by the processor to cause the apparatus to: receive an indication of a time duration, a slot number, or both, for which the precoder is applied to the one or more downlink signals. 24. The apparatus of claim 15, wherein a value of the precoder comprises a static value or a pseudo-random value, and the instructions are further executable by the processor to cause the apparatus to: perform the gain and phase mismatch equalization procedure based at least in part on the value of the precoder. 25. The apparatus of claim 15, wherein the indication of the precoder comprises a first indication of a first precoder, and the instructions are further executable by the processor to cause the apparatus to: receive, via the first indication of the first precoder, a second indication of a second precoder to be applied to the one or more downlink signals after a threshold time duration; and perform the gain and phase mismatch equalization procedure in accordance with the second precoder. 26. The apparatus of claim 15, wherein the instructions are further executable by the processor to cause the apparatus to: receive, from a network entity, a periodicity indication that indicates a periodicity for which the UE is to perform the gain and phase mismatch equalization procedure based at least in part on one or more operating factors of the network entity. 27. The apparatus of claim 15, wherein the gain and phase mismatch equalization procedure comprises an in-phase quadrature-phase mismatch equalization procedure. 28. The apparatus of claim 15, wherein the estimated gain and phase mismatch is a frequency-dependent gain and phase mismatch. 29. An apparatus for wireless communication at a user equipment (UE), comprising: means for receiving, via a downlink channel, a downlink message comprising an indication of a precoder applied to one or more downlink signals; means for receiving the one or more downlink signals using at least one demodulation reference signal and the precoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; means for performing an iterative channel estimation procedure to estimate the downlink channel; means for performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the precoder; and means for receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. 30. A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE), the code comprising instructions executable by a processor to: receive, via a downlink channel, a downlink message comprising an indication of a precoder applied to one or more downlink signals; receive the one or more downlink signals using at least one demodulation reference signal and the precoder, wherein the one or more downlink signals are at least partially mismatched in phase; perform an iterative channel estimation procedure to estimate the downlink channel; perform a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the precoder; and receive one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. |
[0090] In some cases, the one or more transmission data signals s(ƒ) may be passed to an IQ modulator 310 (e.g., one or more of IQ modulator 310-a. IQ modulator 310-b. IQ modulator 310-c, IQ modulator 310-d). The IQ modulator 310 may include one or more components such as a conjugate block 315, a first filter 320-a (mathematically referred to as k 1 (ƒ) or K 1 (ƒ)), a second filter 320-b (mathematically referred to as k 2 (ƒ) or K 2 (ƒ)), and a summing component 325. The first filter 320-a and the second filter 320-b may be functions of a gain and a phase. The IQ modulator 310 may process the transmission data signals s(ƒ) to modulate the transmission data signals with various amplitude and phase configurations. For example, a network entity 105 may use the IQ modulator 310 to generate a variety of different RF signals with unique amplitude and phase modulations.
[0091] In some implementations, however, the IQ modulator 310 may introduce error into the MIMO system 300. For example, hardware components of IQ modulator 310 may be non-ideal, or the IQ modulator 310 may produce IQ signals with non-ideal characteristics (e g., inaccurate relative to an expected output), such as gain and phase errors, or the IQ modulator 310 may have some other defect. As such, correcting the error (e.g., IQ gain and phase mismatch error) may be advantageous for a wireless communications system (e.g., wireless communications system 100, wireless communications sy stem 200, etc.) to increase system performance.
[0092] In some cases, the IQ mismatch errors introduced by the IQ modulator 310 may be identified (e.g., reflected) by adding the conjugate of the image of the one or more input transmission signals s(ƒ). For example, the processing performed by IQ modulator 310 on the transmission data signal s(ƒ) may result in an output transmission data signal s out (ƒ) and may be described as where represents the IQ mismatch error (e.g., an undesired portion, or a portion to be cancelled or corrected). For example, a single signal processing branch may have an IQ modulator 310 which may receive a transmission data signal (e.g., from the digital precoder 305) s 1 (ƒ). The IQ modulator 310 may process the signal s 1 (ƒ) with a conjugate block 315, a first filter 320-a, a second filter 320-b, and a summing component 325 to produce an output signal
[0093] One or more transmitters (e.g., transmitter 330-a) may receive a processed transmission data signal s out (ƒ) and transmit the signal via a communication channel 335. The communication channel 335 may alter the transmitted data signal s out (ƒ) based on various conditions of the channel. The communication channel 335 may be mathematically referred to as H(ƒ). The effect that the communication channel 335 has on the transmitted data signal may be mathematically described as where refers to the signal observed by a receiver (e.g., the UE 115-b).
[0094] In some examples, the MIMO system 300 may receive one or more input signals where nss is the number of input signals in the MIMO system 300. The combination of the input signals may be defined as a matrix The digital precoder 305 may receive the combination of input signals and produce one or more data signals for each signal processing branch (e.g., IQ modulator 310-a and transmitter 330-a) in the system, where ntx is the number of transmission data signals. The combination of the transmission data signals may also be described by a matrix As discussed above, each IQ modulator 310 may have two filters (e.g., the first filter 320-a and the second filter 320- b). The combination of each filter may also be defined by respective matrices Using such definitions, the matrix expression for the observed signal with the IQ mismatch (e.g., FDRSB) may be represented by Equation 1 below:
[0095] In Equation 1, indicates an element-wise matrix multiplication, and additive noise terms may be absent from the matrix expression. The term s(ƒ).* k 1 (ƒ) may represent the desired part of the observed signal and s*(— /ƒ).* k 2 (ƒ) may represent the error or mismatch.
[0096] One or more UEs 115 in a coverage area 110-b may receive one or more signals generated by the digital precoder 305, the one or more IQ modulators, and the one or more transmitters via the communication channel 335. In accordance with aspects of the present disclosure, each UE 115 (e.g., instead of or in addition to a network entity 105) may perform the gain and phase mismatch estimation and cancellation for the one or more received signals. Since the gain and phase mismatch may occur at the IQ modulator 310 (e.g., after the digital precoder 305 but before transmission over communication channel 335), the one or more UEs 115 may use information about the digital precoder 305 (e.g., in separate from information about the communication channel 335) to perform the gain and phase mismatch estimation and cancellation. In some cases, one or more UEs 115 may receive, from a network entity 105, an indication of the precoder (e.g., precoder coefficients, precoder value), and may perform the estimation and cancellation based on the indication.
[0097] In some cases, the one or more UEs 115 may have a channel equalizer to improve communications (e.g., with a network entity 105). In such cases, the UE may employ the channel equalizer to perform additional operations (as described with reference to FIG. 4) to perform the IQ gain and phase mismatch estimation and cancellation. For example, a UE 115 may perform IQ gain and phase estimation and cancellation and channel equalization simultaneously.
[0098] FIG. 4 illustrates an example of a flowchart 400 that supports joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling in accordance with one or more aspects of the present disclosure. The operations of the flowchart 400 may be implemented by a UE 115, a network entity 105, or some other device. For example, the operations of the method described by flowchart 400 may be performed by a UE 115 as described with reference to FIGs. 1 through 3. The method described by flowchart 400 may allow a UE 115, or some other device, to perform efficient gain and phase mismatch (e.g., IQ mismatch) estimation and cancellation. In some cases, for example, the UE 115 may use estimation over a DMRS, an estimated communication channel (e.g., physical channel), a precoder, an observed signal, or any combination thereof, to perform the method described by flowchart 400.
[0099] As described in FIG. 3, the observed signal at the one or more receivers (e.g., one or more UEs 115) may be described with the additive noise w(ƒ) by Equation 2 below: [0100] It may be noted that, a vector may be represented as a diagonal matrix. As such, an elementwise vector multiplication expression a .* b may be equivalently represented as a matrix multiplication expression diag(b) * a. Applying that property and further simplifying, the above equation may be equivalently written as Equation 3 below:
[0101] Written in this form, the term may represent the gain and phase mismatch that the UE may estimate and cancel as part of method described by flowchart
400. The estimated gain and phase mismatch may be referred to herein as Φ(ƒ) where
[0102] At 405, the method may include reproducing the transmitted signal using the DMRS and precoder coefficients. In some cases, the transmitted signal may be represented by where s(ƒ) is the transmitted signal (e.g., after precoding and before IQ modulation), P(ƒ) is the applied precoder, and is the DMRS. In order for a UE 115 to reproduce the transmitted signal (e.g., downlink signal from a network entity 105), the UE 115 may use information about the applied precoder P(ƒ) (e.g., applied by the network entity 105) along with the DMRS .
[0103] At 410, the method may include performing channel estimation using any channel estimation method (e.g., least square estimation, minimum mean square error estimation, linear, minimum mean square error estimation, etc.) on the channel y Using the channel estimation and the gain and phase mismatch definitions as previously defined, the above equation may simplify to Equation 4:
[0104] In some examples, the channel estimation may be affected by the IQ impairment (e.g., through K 1 ), so an interactive channel estimation procedure may be performed to estimate the channel (e.g., chest ~IQ mismatch impairment estimation ~ chest). [0105] At 415, the method may include estimating the gain and phase mismatch (e.g., IQ mismatch, FDRSB impairment) by using the estimated channel and the reproduced transmission signal s(ƒ). For example, a UE 115 (or some other wireless or network device) may use a measurement parameter Q(ƒ) to perform the estimation. The UE 115 may take the observed signal y(ƒ) and subtract the desired portion to obtain Again, using the diagonal matrix property the equation for Q(ƒ) can be expanded as in Equation 5 below : and may be further simplified based on Equation 6 below: such that the measurement parameter Q(f) may be expressed as Q(ƒ) = U(ƒ) · Φ(ƒ) + w(ƒ). The UE 115 may then calculate gain and phase mismatch parameters and with Equations 7 and 8 below :
[0106] In some examples, since the channel estimation at 410 may depend on a parameter of an IQ modulator (e.g., K 1 (ƒ)), and 410 and 415 may be performed iteratively as show n by 420. For example, a UE may perform the operations as described by 415 to obtain an estimation of the gain and phase mismatch. The UE may then follow 420 to perform the channel estimation at 410 and use additional information obtained in the estimation performed at 415. The UE, or some other device, may follow 420 and thereby repeat 410 and 415 one or more times, or may not follow 420 and continue to 425. [0107] In some cases, the UE 115 may communicate to the network entity 105 whether the gain and phase estimation was successful or unsuccessful. For example, the UE 115 may determine that the estimation performed in 415 was unsuccessful and may request that the network entity 105 keep the precoder the same until the UE 115 successfully performs the gain and phase estimation.
[0108] At 425, the method may include performing the gain and phase mismatch cancellation and equalization. Continuing from Equation 4, reproduced below: and recalling that the transmitted signal s(ƒ) is the product of the precoder and the input signal, s(ƒ) = p(ƒ)x(ƒ). the above equation may be equivalently written as Equation 9:
Further, the conjugate image of y(ƒ) may be y*(—ƒ) and can be written as Equation 10;
To represent the cancellation and equalization, the terms x(±ƒ), y(±ƒ), and w(±ƒ) may be defined respectively as:
For example, in a case where there are four receivers, y(ƒ), y*(—ƒ), and y(±ƒ) may be defined as follows: [0109] Using the structures and definitions described above, the mathematical expressions for y(ƒ) and y*(—ƒ) may be condensed into a single matrix Equation 11:
[0110] To simplify, may be defined as: and the Equation 11 may be simplified to Equation 12:
[0111] For example, the UE 115 may evaluate Equation 12 during 425 (e.g., using an advanced equalizer) to cancel and equalize the gain and phase mismatch. In such examples, the following may be assumed: y(ƒ)∈(nrx,1), x(ƒ)∈(nss,1), p(ƒ)∈(ntx,nss), s(ƒ)∈(ntx,1), H(ƒ)∈(nrx,ntx), Φ(ƒ)∈(ntx,1), y(±ƒ)∈(2·nrx,1), w(±ƒ)∈(2·nrx,1), and x(±ƒ)∈(2·nss,1).
[0112] In some cases, a UE 115 may perform 425 without any additional processing hardware (e.g., an advanced equalizer). Additionally or alternatively, the UE 115 may calculate channel equalization parameters and with the following Equations 13 and 14:
As such, at 425, processing may move from the receiver antenna domain into the layers domain and perform the IQ gain and phase mismatch cancellation simultaneously (e.g., in the same process).
[0113] FIG. 5 illustrates an example of a process flow 500 that supports joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling in accordance with one or more aspects of the present disclosure. In some examples, process flow 500 may implement aspects of wireless communications system 100 or wireless communications system 200. For example, process flow 500 may support configurations for indicating a precoder to a UE for gain and phase mismatch estimation and cancellation for associated communication signals. [0114] In the following description of process flow 500, the operations between UE 115-f and network entity 105-b may be transmitted in a different order than the order shown, or other operations may be added or removed from the process flow 500. For example, some operations may also be left out of process flow 500, or UE 115-f and network entity 105-b may be performed in different orders or at different times other operations may be added to process flow 500. Although UE 115-f and network entity 105-b are shown performing the operations of process flow 500, some aspects of some operations may also be performed by one or more other wireless or network devices. [0114] At 505, the UE 115-f may receive, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals. For example, the UE 115-f may receive one or more downlink signals using at least one DMRS and the precoder, where the one or more downlink signals are at least partially mismatched in gain and phase. [0115] In some cases, the UE 115-f may receive an indication of a time duration, a slot number, or both, for which the precoder is applied to the one or more downlink signals. Additionally, or alternatively, the UE 115-f may receive the precoder indication via a set of downlink precoded data, where the UE 115-f may determine one or more precoder coefficients based on the set of downlink precoded data. In some cases, the indication of the precoder may include a first indication of a first precoder. The UE 115- f may receive, via the first indication of the first precoder, a second indication of a second precoder to be applied to the one or more downlink signals after a threshold time duration. [0116] In some cases, the UE 115-f may apply the one or more precoder coefficients to the one or more downlink signals. For example, the UE 115-f may use a reference signal (e.g., DMRS) and the one or more precoder coefficients to reproduce a transmitted signal. In some cases, a value of the precoder may include a static value or a pseudo-random value. Additionally, or alternatively, the UE 115-f may perform a gain and phase mismatch equalization procedure based on the value of the precoder. In some other cases, the UE 115-f may perform the gain and phase mismatch equalization procedure in accordance with the second precoder received at 505. [0117] At 510, the UE 115-f may receive, from the network entity 105-b, a periodicity indication that indicates a periodicity for which the UE 115-f is to perform the gain and phase mismatch equalization procedure based on one or more operating factors of the network entity 105-b. For example, in some cases, the gain and phase mismatch may have a low rate of variation and, as such, the UE 115-f may not perform the gain and phase estimation and equalization for every slot (e.g., to reduce power costs or reduce processing resource usage). For example, the UE 115-f may be able to us the gain and phase mismatch information obtained during one or more previous slots to perform the estimation and equalization for a current slot. [0118] At 515, the UE 115-f may perform an iterative channel estimation procedure to estimate the downlink channel. In some cases, the UE 115-f may perform the iterative channel estimation procedure to estimate a physical channel associated with the one or more downlink signals using the at least one DMRS. The UE 115-f may estimate the estimated gain and phase mismatch based on the estimated physical channel, the precoder, or both. [0119] At 520, the UE 115-f may estimate a gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the precoder. For example, the network entity 105-b may use an IQ modulator after applying a precoder and before transmitting a signal to the UE 115-f. At 520, the UE 115-f may estimate the gain and phase mismatch (e.g., IQ impairment) in order to perform a gain and phase cancellation and equalization procedure. In some cases, the estimated gain and phase mismatch may be a frequency-dependent gain and phase mismatch. [0120] At 525, the UE 115-f may perform at least a second channel estimation procedure based on the estimated gain and phase mismatch (e.g., at 520). For example, a UE 115-f may perform a first channel estimation procedure at 515 and a first gain and phase mismatch estimation at 520. However, the gain and phase mismatch performed at 520 may further affect the channel estimation. As such, the UE 115-f may perform a second channel estimation procedure to account for the effect of the gain and phase mismatch performed at 520. [0121] At 530, the UE 115-f may perform at least a second gain and phase mismatch estimation procedure based on the second channel estimation procedure at 525. Additionally or alternatively, the UE 115-f may continue to perform more channel estimation and gain and phase mismatch estimation procedures to provide a more accurate channel estimation. [0122] At 535, the UE 115-f may perform a gain and phase mismatch equalization procedure to equalize an estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the precoder. In some cases, the UE 115-f may reproduce the one or more downlink signals to use for the gain and phase mismatch equalization procedure based on at least one DMRS and the precoder received at 505. [0123] In some cases, the UE 115-f may perform the gain and phase mismatch equalization procedure and equalize the estimated gain and phase mismatch of the one or more downlink signals simultaneously. Additionally, or alternatively, the UE 115-f may cancel at least a portion of the estimated gain and phase mismatch. In such cases, the gain and phase mismatch equalization procedure may include an IQ mismatch equalization procedure. [0124] At 540, the UE 115-f may receive one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. For example, the UE 115-f may apply the calculations performed during the procedure at 535 to the signals received at 540. As such, the UE 115-f may cancel the gain and phase mismatch of one or more received signals at 540 based on the procedure performed at 535. [0125] FIG.6 illustrates a block diagram 600 of a device 605 that supports joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling in accordance with one or more aspects of the present disclosure. The device 605 may be an example of aspects of a UE 115 as described herein. The device 605 may include a receiver 610, a transmitter 615, and a communications manager 620. The device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). [0126] The receiver 610 may provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling). Information may be passed on to other components of the device 605. The receiver 610 may utilize a single antenna or a set of multiple antennas. [0127] The transmitter 615 may provide a means for transmitting signals generated by other components of the device 605. For example, the transmitter 615 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling). In some examples, the transmitter 615 may be co-located with a receiver 610 in a transceiver module. The transmitter 615 may utilize a single antenna or a set of multiple antennas. [0128] The communications manager 620, the receiver 610, the transmitter 615, or various combinations thereof or various components thereof may be examples of means for performing various aspects of joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling as described herein. For example, the communications manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof may support a method for performing one or more of the functions described herein. [0129] In some examples, the communications manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), a central processing unit (CPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a microcontroller, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some examples, a processor and memory coupled with the processor may be configured to perform one or more of the functions described herein (e.g., by executing, by the processor instructions stored in the memory) [0130] Additionally, or alternatively, in some examples, the communications manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof may be implemented in code (e.g., as communications management software or firmware) executed by a processor. If implemented in code executed by a processor, the functions of the communications manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof may be performed by a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting a means for performing the functions described in the present disclosure). [0131] In some examples, the communications manager 620 may be configured to perform various operations (e.g., receiving, obtaining, monitoring, outputting, transmitting) using or otherwise in cooperation with the receiver 610, the transmitter 615, or both. For example, the communications manager 620 may receive information from the receiver 610, send information to the transmitter 615, or be integrated in combination with the receiver 610, the transmitter 615, or both to obtain information, output information, or perform various other operations as described herein. [0132] The communications manager 620 may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager 620 may be configured as or otherwise support a means for receiving, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals. The communications manager 620 may be configured as or otherwise support a means for receiving the one or more downlink signals using at least one DMRS and the precoder, where the one or more downlink signals are at least partially mismatched in gain and phase. The communications manager 620 may be configured as or otherwise support a means for performing an iterative channel estimation procedure to estimate the downlink channel. The communications manager 620 may be configured as or otherwise support a means for performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the precoder. The communications manager 620 may be configured as or otherwise support a means for receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. [0133] By including or configuring the communications manager 620 in accordance with examples as described herein, the device 605 (e.g., a processor controlling or otherwise coupled with the receiver 610, the transmitter 615, the communications manager 620, or a combination thereof) may support techniques for reduced design complexity and more efficient utilization of communication resources. [0134] FIG.7 illustrates a block diagram 700 of a device 705 that supports joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling in accordance with one or more aspects of the present disclosure. The device 705 may be an example of aspects of a device 605 or a UE 115 as described herein. The device 705 may include a receiver 710, a transmitter 715, and a communications manager 720. The device 705 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). [0135] The receiver 710 may provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling). Information may be passed on to other components of the device 705. The receiver 710 may utilize a single antenna or a set of multiple antennas. [0136] The transmitter 715 may provide a means for transmitting signals generated by other components of the device 705. For example, the transmitter 715 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling). In some examples, the transmitter 715 may be co-located with a receiver 710 in a transceiver module. The transmitter 715 may utilize a single antenna or a set of multiple antennas. [0137] The device 705, or various components thereof, may be an example of means for performing various aspects of joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling as described herein. For example, the communications manager 720 may include a precoder component 725, a downlink signal management component 730, a channel estimation component 735, a mismatch equalization component 740, or any combination thereof. The communications manager 720 may be an example of aspects of a communications manager 620 as described herein. In some examples, the communications manager 720, or various components thereof, may be configured to perform various operations (e.g., receiving, obtaining, monitoring, outputting, transmitting) using or otherwise in cooperation with the receiver 710, the transmitter 715, or both. For example, the communications manager 720 may receive information from the receiver 710, send information to the transmitter 715, or be integrated in combination with the receiver 710, the transmitter 715, or both to obtain information, output information, or perform various other operations as described herein. [0138] The communications manager 720 may support wireless communication at a UE in accordance with examples as disclosed herein. The precoder component 725 may be configured as or otherwise support a means for receiving, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals. The downlink signal management component 730 may be configured as or otherwise support a means for receiving the one or more downlink signals using at least one DMRS and the precoder, where the one or more downlink signals are at least partially mismatched in gain and phase. The channel estimation component 735 may be configured as or otherwise support a means for performing an iterative channel estimation procedure to estimate the downlink channel. The mismatch equalization component 740 may be configured as or otherwise support a means for performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the precoder. The downlink signal management component 730 may be configured as or otherwise support a means for receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. [0139] FIG.8 illustrates a block diagram 800 of a communications manager 820 that supports joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling in accordance with one or more aspects of the present disclosure. The communications manager 820 may be an example of aspects of a communications manager 620, a communications manager 720, or both, as described herein. The communications manager 820, or various components thereof, may be an example of means for performing various aspects of joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling as described herein. For example, the communications manager 820 may include a precoder component 825, a downlink signal management component 830, a channel estimation component 835, a mismatch equalization component 840, a mismatch estimation component 845, a precoder application component 850, a mismatch cancellation component 855, a mismatch equalization and cancellation component 860, a signal reproduction component 865, a periodicity component 870, or any combination thereof. Each of these components may communicate, directly or indirectly, with one another (e.g., via one or more buses). [0140] The communications manager 820 may support wireless communication at a UE in accordance with examples as disclosed herein. The precoder component 825 may be configured as or otherwise support a means for receiving, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals. The downlink signal management component 830 may be configured as or otherwise support a means for receiving the one or more downlink signals using at least one DMRS and the precoder, where the one or more downlink signals are at least partially mismatched in gain and phase. The channel estimation component 835 may be configured as or otherwise support a means for performing an iterative channel estimation procedure to estimate the downlink channel. The mismatch equalization component 840 may be configured as or otherwise support a means for performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the precoder. In some examples, the downlink signal management component 830 may be configured as or otherwise support a means for receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. [0141] In some examples, the channel estimation component 835 may be configured as or otherwise support a means for performing the iterative channel estimation procedure to estimate a physical channel associated with the one or more downlink signals using the at least one DMRS. In some examples, the mismatch estimation component 845 may be configured as or otherwise support a means for estimating the estimated gain and phase mismatch based on the estimated physical channel, the precoder, or both. [0142] In some examples, to support receiving the one or more downlink signals, the precoder application component 850 may be configured as or otherwise support a means for applying the one or more precoder coefficients to the one or more downlink signals. [0143] In some examples, to support performing the iterative channel estimation procedure, the channel estimation component 835 may be configured as or otherwise support a means for performing a first channel estimation procedure. In some examples, to support performing the iterative channel estimation procedure, the mismatch equalization component 840 may be configured as or otherwise support a means for performing the gain and phase mismatch equalization procedure. In some examples, to support performing the iterative channel estimation procedure, the channel estimation component 835 may be configured as or otherwise support a means for performing at least a second channel estimation procedure based on the estimated gain and phase mismatch. [0144] In some examples, to support performing the gain and phase mismatch equalization procedure, the mismatch cancellation component 855 may be configured as or otherwise support a means for cancelling at least a portion of the estimated gain and phase mismatch. [0145] In some examples, to support receiving the downlink message including the indication of the precoder, the downlink signal management component 830 may be configured as or otherwise support a means for receiving the indication of the precoder via a set of downlink precoded data, where one or more precoder coefficients are determined based on the set of downlink precoded data. [0146] In some examples, the mismatch equalization and cancellation component 860 may be configured as or otherwise support a means for performing the gain and phase mismatch equalization procedure and equalizing the estimated gain and phase mismatch of the one or more downlink signals simultaneously. [0147] In some examples, to support receiving the one or more downlink signals, the signal reproduction component 865 may be configured as or otherwise support a means for reproducing the one or more downlink signals to use for the gain and phase mismatch equalization procedure based on the at least one DMRS and the precoder. [0148] In some examples, to support receiving the indication of the precoder, the precoder component 825 may be configured as or otherwise support a means for receiving an indication of a time duration, a slot number, or both, for which the precoder is applied to the one or more downlink signals. [0149] In some examples, a value of the precoder includes a static value or a pseudo-random value, and the mismatch equalization component 840 may be configured as or otherwise support a means for performing the gain and phase mismatch equalization procedure based on the value of the precoder. [0150] In some examples, the indication of the precoder includes a first indication of a first precoder, and the precoder component 825 may be configured as or otherwise support a means for receiving, via the first indication of the first precoder, a second indication of a second precoder to be applied to the one or more downlink signals after a threshold time duration. In some examples, the indication of the precoder includes a first indication of a first precoder, and the mismatch equalization component 840 may be configured as or otherwise support a means for performing the gain and phase mismatch equalization procedure in accordance with the second precoder. [0151] In some examples, the periodicity component 870 may be configured as or otherwise support a means for receiving, from a network entity, a periodicity indication that indicates a periodicity for which the UE is to perform the gain and phase mismatch equalization procedure based on one or more operating factors of the network entity. [0152] In some examples, the gain and phase mismatch equalization procedure includes an IQ mismatch equalization procedure. [0153] In some examples, the estimated gain and phase mismatch is a frequency- dependent gain and phase mismatch. [0154] FIG.9 illustrates a diagram of a system 900 including a device 905 that supports joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling in accordance with one or more aspects of the present disclosure. The device 905 may be an example of or include the components of a device 605, a device 705, or a UE 115 as described herein. The device 905 may communicate (e.g., wirelessly) with one or more network entities 105, one or more UEs 115, or any combination thereof. The device 905 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, such as a communications manager 920, an input/output (I/O) controller 910, a transceiver 915, an antenna 925, a memory 930, code 935, and a processor 940. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., a bus 945). [0155] The I/O controller 910 may manage input and output signals for the device 905. The I/O controller 910 may also manage peripherals not integrated into the device 905. In some cases, the I/O controller 910 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 910 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. Additionally or alternatively, the I/O controller 910 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 910 may be implemented as part of a processor, such as the processor 940. In some cases, a user may interact with the device 905 via the I/O controller 910 or via hardware components controlled by the I/O controller 910. [0156] In some cases, the device 905 may include a single antenna 925. However, in some other cases, the device 905 may have more than one antenna 925, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 915 may communicate bi-directionally, via the one or more antennas 925, wired, or wireless links as described herein. For example, the transceiver 915 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 915 may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 925 for transmission, and to demodulate packets received from the one or more antennas 925. The transceiver 915, or the transceiver 915 and one or more antennas 925, may be an example of a transmitter 615, a transmitter 715, a receiver 610, a receiver 710, or any combination thereof or component thereof, as described herein. [0157] The memory 930 may include random access memory (RAM) and read-only memory (ROM). The memory 930 may store computer-readable, computer-executable code 935 including instructions that, when executed by the processor 940, cause the device 905 to perform various functions described herein. The code 935 may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, the code 935 may not be directly executable by the processor 940 but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some cases, the memory 930 may contain, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices. [0158] The processor 940 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 940 may be configured to operate a memory array using a memory controller. In some other cases, a memory controller may be integrated into the processor 940. The processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks supporting joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling). For example, the device 905 or a component of the device 905 may include a processor 940 and memory 930 coupled with or to the processor 940, the processor 940 and memory 930 configured to perform various functions described herein. [0159] The communications manager 920 may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager 920 may be configured as or otherwise support a means for receiving, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals. The communications manager 920 may be configured as or otherwise support a means for receiving the one or more downlink signals using at least one DMRS and the precoder where the one or more downlink signals are at least partially mismatched in gain and phase. The communications manager 920 may be configured as or otherwise support a means for performing an iterative channel estimation procedure to estimate the downlink channel. The communications manager 920 may be configured as or otherwise support a means for performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the precoder. The communications manager 920 may be configured as or otherwise support a means for receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. [0160] By including or configuring the communications manager 920 in accordance with examples as described herein, the device 905 may support techniques for reduced system complexity, more efficient utilization of communication resources, improved efficiency between devices, and improved utilization of processing capability. [0161] In some examples, the communications manager 920 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the transceiver 915, the one or more antennas 925, or any combination thereof. Although the communications manager 920 is illustrated as a separate component, in some examples, one or more functions described with reference to the communications manager 920 may be supported by or performed by the processor 940, the memory 930, the code 935, or any combination thereof. For example, the code 935 may include instructions executable by the processor 940 to cause the device 905 to perform various aspects of joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling as described herein, or the processor 940 and the memory 930 may be otherwise configured to perform or support such operations. [0162] FIG.10 illustrates a flowchart illustrating a method 1000 that supports joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling in accordance with one or more aspects of the present disclosure. The operations of the method 1000 may be implemented by a UE or its components as described herein. For example, the operations of the method 1000 may be performed by a UE 115 as described with reference to FIGs.1 through 9. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware. [0163] At 1005, the method may include receiving, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals. The operations of 1005 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1005 may be performed by a precoder component 825 as described with reference to FIG.8. [0164] At 1010, the method may include receiving the one or more downlink signals using at least one DMRS and the precoder, where the one or more downlink signals are at least partially mismatched in gain and phase. The operations of 1010 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1010 may be performed by a downlink signal management component 830 as described with reference to FIG.8. [0165] At 1015, the method may include performing an iterative channel estimation procedure to estimate the downlink channel. The operations of 1015 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1015 may be performed by a channel estimation component 835 as described with reference to FIG.8. [0166] At 1020, the method may include performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the precoder. The operations of 1020 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1020 may be performed by a mismatch equalization component 840 as described with reference to FIG.8. [0167] At 1025, the method may include receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. The operations of 1025 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1025 may be performed by a downlink signal management component 830 as described with reference to FIG.8. [0168] FIG.11 illustrates a flowchart illustrating a method 1100 that supports joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling in accordance with one or more aspects of the present disclosure. The operations of the method 1100 may be implemented by a UE or its components as described herein. For example, the operations of the method 1100 may be performed by a UE 115 as described with reference to FIGs.1 through 9. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware. [0169] At 1105, the method may include receiving, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals. The operations of 1105 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1105 may be performed by a precoder component 825 as described with reference to FIG.8. [0170] At 1110, the method may include receiving the one or more downlink signals using at least one DMRS and the precoder, where the one or more downlink signals are at least partially mismatched in gain and phase. The operations of 1110 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1110 may be performed by a downlink signal management component 830 as described with reference to FIG.8. [0171] At 1115, the method may include performing an iterative channel estimation procedure to estimate the downlink channel. The operations of 1115 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1115 may be performed by a channel estimation component 835 as described with reference to FIG.8. [0172] At 1120, the method may include performing the iterative channel estimation procedure to estimate a physical channel associated with the one or more downlink signals using the at least one DMRS. The operations of 1120 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1120 may be performed by a channel estimation component 835 as described with reference to FIG.8. [0173] At 1125, the method may include performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the precoder. The operations of 1125 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1125 may be performed by a mismatch equalization component 840 as described with reference to FIG.8. [0174] At 1130, the method may include estimating the estimated gain and phase mismatch based on the estimated physical channel, the precoder, or both. The operations of 1130 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1130 may be performed by a mismatch estimation component 845 as described with reference to FIG.8. [0175] At 1135, the method may include receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. The operations of 1135 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1135 may be performed by a downlink signal management component 830 as described with reference to FIG.8. [0176] FIG.12 illustrates a flowchart illustrating a method 1200 that supports joint gain and phase mismatch canceller and equalizer for downlink aided by precoder signaling in accordance with one or more aspects of the present disclosure. The operations of the method 1200 may be implemented by a UE or its components as described herein. For example, the operations of the method 1200 may be performed by a UE 115 as described with reference to FIGs.1 through 9. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware. [0177] At 1205, the method may include receiving, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals. The operations of 1205 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1205 may be performed by a precoder component 825 as described with reference to FIG.8. [0178] At 1210, the method may include receiving the one or more downlink signals using at least one DMRS and the precoder, where the one or more downlink signals are at least partially mismatched in gain and phase. The operations of 1210 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1210 may be performed by a downlink signal management component 830 as described with reference to FIG.8. [0179] At 1215, the method may include applying the one or more precoder coefficients to the one or more downlink signals. The operations of 1215 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1215 may be performed by a precoder application component 850 as described with reference to FIG.8. [0180] At 1220, the method may include performing an iterative channel estimation procedure to estimate the downlink channel. The operations of 1220 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1220 may be performed by a channel estimation component 835 as described with reference to FIG.8. [0181] At 1225, the method may include performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the precoder. The operations of 1225 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1225 may be performed by a mismatch equalization component 840 as described with reference to FIG.8. [0182] At 1230, the method may include receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. The operations of 1230 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1230 may be performed by a downlink signal management component 830 as described with reference to FIG.8. [0183] The following provides an overview of aspects of the present disclosure: [0184] Aspect 1: A method for wireless communication at a UE, comprising: receiving, via a downlink channel, a downlink message comprising an indication of a precoder applied to one or more downlink signals; receiving the one or more downlink signals using at least one DMRS and the precoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; performing an iterative channel estimation procedure to estimate the downlink channel; performing a gain and phase mismatch equalization procedure at the UE to equalize an estimated gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the precoder; and receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization procedure. [0185] Aspect 2: The method of aspect 1, further comprising: performing the iterative channel estimation procedure to estimate a physical channel associated with the one or more downlink signals using the at least one DMRS; and estimating the estimated gain and phase mismatch based at least in part on the estimated physical channel, the precoder, or both. [0186] Aspect 3: The method of any of aspects 1 through 2, wherein the indication of the precoder comprises one or more precoder coefficients, wherein receiving the one or more downlink signals further comprises: applying the one or more precoder coefficients to the one or more downlink signals. [0187] Aspect 4: The method of any of aspects 1 through 3, wherein performing the iterative channel estimation procedure further comprises: performing a first channel estimation procedure; performing the gain and phase mismatch equalization procedure; and performing at least a second channel estimation procedure based at least in part on the estimated gain and phase mismatch. [0188] Aspect 5: The method of any of aspects 1 through 4, wherein performing the gain and phase mismatch equalization procedure further comprises: cancelling at least a portion of the estimated gain and phase mismatch. [0189] Aspect 6: The method of any of aspects 1 through 5, wherein receiving the downlink message comprising the indication of the precoder further comprises: receiving the indication of the precoder via a set of downlink precoded data, wherein one or more precoder coefficients are determined based at least in part on the set of downlink precoded data. [0190] Aspect 7: The method of any of aspects 1 through 6, further comprising: performing the gain and phase mismatch equalization procedure and equalizing the estimated gain and phase mismatch of the one or more downlink signals simultaneously. [0191] Aspect 8: The method of any of aspects 1 through 7, wherein receiving the one or more downlink signals further comprises: reproducing the one or more downlink signals to use for the gain and phase mismatch equalization procedure based at least in part on the at least one DMRS and the precoder. [0192] Aspect 9: The method of any of aspects 1 through 8, wherein receiving the indication of the precoder further comprises: receiving an indication of a time duration, a slot number, or both, for which the precoder is applied to the one or more downlink signals. [0193] Aspect 10: The method of any of aspects 1 through 9, wherein a value of the precoder comprises a static value or a pseudo-random value, the method further comprising: performing the gain and phase mismatch equalization procedure based at least in part on the value of the precoder. [0194] Aspect 11: The method of any of aspects 1 through 10, wherein the indication of the precoder comprises a first indication of a first precoder, the method further comprising: receiving, via the first indication of the first precoder, a second indication of a second precoder to be applied to the one or more downlink signals after a threshold time duration; and performing the gain and phase mismatch equalization procedure in accordance with the second precoder. [0195] Aspect 12: The method of any of aspects 1 through 11, further comprising: receiving, from a network entity, a periodicity indication that indicates a periodicity for which the UE is to perform the gain and phase mismatch equalization procedure based at least in part on one or more operating factors of the network entity. [0196] Aspect 13: The method of any of aspects 1 through 12, wherein the gain and phase mismatch equalization procedure comprises an in-phase quadrature-phase (IQ) mismatch equalization procedure. [0197] Aspect 14: The method of any of aspects 1 through 13, wherein the estimated gain and phase mismatch is a frequency-dependent gain and phase mismatch. [0198] Aspect 15: An apparatus for wireless communication at a UE, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any of aspects 1 through 14. [0199] Aspect 16: An apparatus for wireless communication at a UE, comprising at least one means for performing a method of any of aspects 1 through 14. [0200] Aspect 17: A non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform a method of any of aspects 1 through 14.It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined. [0201] Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein. [0202] Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. [0203] The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed using a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor but, in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration). [0204] The functions described herein may be implemented using hardware, software executed by a processor, firmware, or any combination thereof. If implemented using software executed by a processor, the functions may be stored as or transmitted using one or more instructions or code of a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. [0205] Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one location to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc. Disks may reproduce data magnetically, and discs may reproduce data optically using lasers. Combinations of the above are also included within the scope of computer-readable media. [0206] As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.” [0207] The term “determine” or “determining” encompasses a variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, investigating, looking up (such as via looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” can include receiving (e.g., receiving information), accessing (e.g., accessing data stored in memory) and the like. Also, “determining” can include resolving, obtaining, selecting, choosing, establishing, and other such similar actions. [0208] In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label. [0209] The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples. [0210] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.