CN104486272A - Feedback signal correcting method and device - Google Patents
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Abstract
The embodiment of the invention provides a feedback signal correcting method and device. The method and the device are used for correcting direct current leakage, amplitude unbalance and phase unbalance due to a ZIF (zero intermediate frequency) architecture in feedback signals. The method comprises the following steps that feedback signals are converted into synchronous feedback signals realizing the same time, the same phase and the same amplitude as transmitting signals; direct current bias parameters, amplitude unbalance parameters and phase unbalance parameters of the transmitting signals and the synchronous feedback signals are respectively calculated; the direct current bias parameters, the amplitude unbalance parameters and the phase unbalance parameters of the synchronous feedback signals are corrected according to the direct current bias parameters, the amplitude unbalance parameters and the phase unbalance parameters of the transmitting signals, and direct current bias correcting parameters, amplitude unbalance correcting parameters and phase unbalance correcting parameters of the synchronous feedback signals are obtained; the synchronous feedback signals are corrected according to the direct current bias correcting parameters, the amplitude unbalance correcting parameters and the phase unbalance correcting parameters.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for correcting a feedback signal.
Background
The design goal of the base station transmitter and receiver is to provide reasonable performance index for the system design with the lowest cost. To achieve this goal, it is desirable to improve the performance of a particular device to simplify the overall design of the system. At present, a ZIF (Zero Intermediate Frequency) technology is generally adopted in a Radio Frequency link, main power for driving the development of the technology is derived from the performance advantage of an RF (Radio Frequency) to baseband scheme, and the complexity and cost of a system can be reduced while the performance is improved.
The ZIF technology directly moves signals from zero frequency to radio frequency through frequency conversion, image interference does not exist, channel selection is carried out at a baseband, only a low-pass filter is needed, the ZIF technology is simple in structure and easy to integrate, and cost and power consumption are reduced. However, the ZIF architecture introduces dc offset and two-way amplitude and phase imbalance due to mismatching of two-way analog circuit components of the in-phase component I-path and the quadrature component Q-path, and the following formula is shown:
wherein, I (t) represents I path signal, Q (t) represents Q path signal, omegaloRepresenting the carrier frequency, Δ diThe DC offset of the path I is represented, which causes subsequent local oscillator leakage; Δ dqThe DC offset of the Q path is represented, which causes subsequent local oscillator leakage; giRepresents the gain of the I path; gqDenotes the gain of q-way, if gi≠gqThe amplitudes of the path I and the path Q are unbalanced, so that the sideband of the mirror image is improved;which represents the phase deviation of the I channel,representing the phase deviation of the Q channel, the deviation of the phases of these two signals is actually of interest:θ0is the initial phase, typically zero.
The above equation (1) can be simplified as follows:
wherein,indicating the phase offset of the I channel relative to the Q channel,is equal togiqRepresenting the amplitude ratio of the I and Q paths.
The DPD (Digital Pre-Distortion) processing apparatus calculates DPD coefficients by receiving feedback signals and stores the DPD coefficients in a Look-Up Table (LUT). The radio frequency link of the DPD processing device adopts a ZIF architecture, so that the ZIF correction is usually required to be carried out on the feedback signal before the DPD coefficient is calculated, so as to eliminate the imbalance and direct current leakage of a feedback channel and ensure that the DPD result is more accurate.
The existing ZIF correction algorithm is usually over corrected, so that the unbalance and the direct current leakage of a feedback channel are corrected, and the unbalance and the direct current leakage of a signal are also corrected.
Disclosure of Invention
The embodiment of the invention provides a method and a device for correcting a feedback signal, which are used for solving the problem of excessive correction of the feedback signal.
The method for correcting the feedback signal provided by the embodiment of the invention comprises the following steps:
converting the feedback signal into a synchronous feedback signal which is at the same time, in phase and at the same amplitude as the transmitting signal;
respectively calculating direct current offset parameters, amplitude imbalance parameters and phase imbalance parameters of the transmitting signals and the synchronous feedback signals;
correcting the direct current bias parameter, the amplitude imbalance parameter and the phase imbalance parameter of the synchronous feedback signal according to the direct current bias parameter, the amplitude imbalance parameter and the phase imbalance parameter of the transmitting signal to obtain a direct current bias correction parameter, an amplitude imbalance correction parameter and a phase imbalance correction parameter of the synchronous feedback signal;
and correcting the synchronous feedback signal according to the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal.
The correction device of the feedback signal provided by the embodiment of the invention comprises:
the first synchronization module is used for converting the feedback signal into a synchronous feedback signal which is at the same time, in phase and at the same amplitude as the transmitting signal;
the parameter calculation module is used for calculating a direct current offset parameter, an amplitude imbalance parameter and a phase imbalance parameter of the transmitting signal and the synchronous feedback signal respectively;
the parameter correction module is used for correcting the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the synchronous feedback signal according to the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the transmitting signal to obtain the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal;
and the signal correction module is used for correcting the synchronous feedback signal according to the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal.
In the embodiment of the invention, a feedback signal is converted into a synchronous feedback signal which is in the same phase and amplitude as a transmitting signal, the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the transmitting signal and the synchronous feedback signal are respectively calculated, the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the synchronous feedback signal are corrected according to the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the transmitting signal to obtain the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal, and the synchronous feedback signal is corrected according to the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal; the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the synchronous feedback signal are corrected, so that the direct current leakage, the amplitude imbalance and the phase imbalance of the transmission signal are eliminated, the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal are obtained, the direct current leakage, the amplitude imbalance and the phase imbalance of the signal are reserved for the correction result of the synchronous feedback signal, and the problem of excessive correction is solved.
Drawings
Fig. 1 is a flowchart of a method for correcting a feedback signal according to an embodiment of the present invention;
fig. 2 and fig. 3 are schematic diagrams illustrating the processing effect of the feedback signal according to the embodiment of the present invention;
fig. 4 is a schematic diagram of a process of calculating a dc offset parameter, an amplitude imbalance parameter, and a phase imbalance parameter according to an embodiment of the present invention;
fig. 5 is a schematic diagram illustrating a ZIF modification process in a DPD processing apparatus according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a feedback signal correction apparatus according to an embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a method and a device for correcting a feedback signal, which are used for correcting direct current leakage, amplitude imbalance and phase imbalance caused by a ZIF (zero-crossing filter) architecture in the feedback signal and simultaneously reserving the direct current leakage, the amplitude imbalance and the phase imbalance of the signal. The following describes embodiments of the present invention in detail with reference to the accompanying drawings.
Referring to fig. 1, a method for correcting a feedback signal according to an embodiment of the present invention includes:
and S110, converting the feedback signal into a synchronous feedback signal which is at the same time, in phase and in amplitude with the transmitting signal.
The transmission signal refers to a digital signal processed by DPD, and is transmitted in the form of an analog signal after being processed by DAC, modulation, amplification and the like; the feedback signal refers to a digital signal obtained by the receiver after receiving the sent analog signal and performing demodulation, ADC and other processing.
S110 specifically comprises: calculating the time delay between the feedback signal and the transmitting signal, and correcting the feedback signal into a first correction signal according to the time delay; calculating a phase offset between the feedback signal and the transmission signal, and correcting the first correction signal into a second correction signal according to the phase offset; and calculating a ratio value between the root mean square of the amplitude of the feedback signal and the root mean square of the amplitude of the transmitting signal, and correcting the second correction signal into the synchronous feedback signal according to the ratio value.
Further, calculating a time delay between the feedback signal and the transmit signal comprises:
determining sampling point positions corresponding to peak values of correlation functions of the feedback signal and the transmitting signal;
and determining the time delay of the feedback signal and the transmitting signal according to the sampling point position corresponding to the peak value of the correlation function of the feedback signal and the transmitting signal.
Further, calculating a phase offset between the feedback signal and the transmit signal comprises:
determining a phase corresponding to a peak value of a correlation function of the feedback signal and the transmission signal;
and determining the phase deviation of the feedback signal and the transmitting signal according to the phase corresponding to the peak value of the correlation function of the feedback signal and the transmitting signal.
The conversion process is described in detail below with reference to equations.
And recording the feedback signal as y, recording the transmission signal as z, and performing correlation operation on y and z to find a peak value max _ data of the correlation operation and a sampling point position max _ pos corresponding to the peak value, namely [ max _ data, max _ pos ] ═ max (xcorr (y, z)), wherein xcorr represents the correlation operation, and max represents taking the peak value.
Judging the value of the feedback signal y, and if the value of the feedback signal y is less than the threshold value, judging that the peak value is not searched, and reselecting the feedback signal y; the threshold _ cor _ valid is determined according to the amount of data and the average amplitude of data, for example, the average amplitude of data is 5230, there are 4000 data correlations, so that the correlation value max _ value of the signal is 5230^2 ^ 4000 ^ 1.0941e +011, and the threshold _ cor _ valid can take the value of 1.0e +011 for the sake of safety.
On the contrary, if | max _ data | ≧ threshold _ cor _ valid, the peak is valid, and the delay point index of the feedback signal is ═ max _ pos-max _ len; where max _ len refers to the number of sample points of the transmitted signal. And further performing time delay adjustment on the feedback signal according to the index: if the sampling point range of the transmitted signal is [ start: start + data _ len ], the sampling point range of the feedback signal after delay adjustment is [ start + index: start + data _ len + index ], and data _ len refers to the final sampling length. Thus, a feedback signal and a transmission signal having the same time delay are obtained.
Then, the amplitude of the feedback signal is adjusted, and the feedback signal and the transmitting signal after time delay adjustment are still expressed by y and z, then
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in this way, a feedback signal is obtained which has the same amplitude as the transmitted signal.
Finally, the phase of the feedback signal is adjusted, and the calculation formula is as follows:
in this case, the phase is adjusted by calculating the phase and setting y to y · exp (-j θ).
Through the above processing, the feedback signal y is obtained which is in the same phase and amplitude as the transmission signal z. Before predistortion, the amplitudes of both the real and imaginary parts of the feedback signal y and the transmit signal z can be aligned, not just the power of the signals, as shown in fig. 2 and 3.
Further, before converting the feedback signal into a synchronous feedback signal that is in-phase and of the same amplitude as the transmit signal, the method comprises the steps of:
determining that the power of the feedback signal is within a preset range.
Power of feedback signalToo low indicates that the collected feedback signal cannot well reflect the nonlinearity of the power amplifier, and if the power of the feedback signal is too high, the oversaturation of the feedback ADC is easily caused. Power (dbfs) calculation of the feedback signal y:n is the length of the feedback signal, and is generally 4096-32768. The threshold value for determining whether the power is too low or too high may be determined based on device parameters.
And S120, respectively calculating the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the transmitting signal and the synchronous feedback signal.
The calculation methods of the dc offset parameter, the amplitude imbalance parameter, and the phase imbalance parameter are the same regardless of the transmission signal or the feedback signal, and are shown in fig. 4 and described in detail below.
Firstly, the method comprises the following steps: calculating a direct current bias parameter:
for the I-path component ri and the Q-path component rq of any signal r, the dc offset parameter is obtained by statistical calculation:
wherein K is a sampling point, and the maximum value is K.
II, secondly: calculation of amplitude imbalance:
note that the 3G/4G system transmits modulated signals, such as: quadrature Phase Shift Keying (QPSK), 64-bit Quadrature Amplitude Modulation (QAM); the I, Q paths have the same amplitude and only have different signs, after the multi-carrier superposition, the I/Q amplitudes in a period of time statistics should be theoretically the same, and if the statistical amplitudes in a period of time are different, it indicates that the amplitudes of the I, Q paths are caused by different gains of the I, Q paths of the analog path.
The I-path amplitude statistic value amp _ ri and the Q-path amplitude statistic value amp _ rq are respectively obtained through statistics in the following modes:
the amplitude imbalance parameter is then:
thirdly, the method comprises the following steps: calculation of phase imbalance:
the received Q-path modulation signal is represented as: rq (t) ([ I (t)) sin (θ) + Q (t) cos (θ) ], where the phase error θ of the I and Q paths of the ideal quadrature modulator is 0. If the quadrature modulator is an ideal quadrature modulator: rq (t) ([ i (t)) sin (0) + q (t)) cos (0) ] ═ q (t)), where the received rq (t) signal is exactly the q (t) signal sent by the transmitter, and if θ ≠ 0, the signal received by the receiving channel at this time is as follows:
rq(t)＝Q(t)cos(θ)+ri(t)sin(θ)
if the originally transmitted q (t) signal is required, it is derived by the following derivation:
Q(t)cos(θ)＝rq(t)-ri(t)sin(θ)
thus, the original Q (t) signal is derived
Wherein, rq (t) and ri (t) are known signals, and therefore, it is necessary to obtain I, Q phase difference θ, which is the key to obtain the signal of the first Q path.
If the I/Q two paths are orthogonal, then there isThen the calculation formula when estimating the phase difference of the two paths is as follows:
θ＝arcsin(Pest)
the I, Q two paths RI (K) and RQ (K) of the feedback signal are a series of data and are therefore represented by K-dimensional vectors RI and RQ, respectively, where P isestConsidered as the angle of the K-dimensional vector. The formula of the included angle between the K-dimensional vector RI and the RQ is as follows:
and calculating the included angle of the I, Q two paths by the angle calculation of the K vectors.
S130, correcting the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the synchronous feedback signal according to the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the transmitting signal to obtain a direct current offset correction parameter, an amplitude imbalance correction parameter and a phase imbalance correction parameter of the synchronous feedback signal.
S130 specifically includes:
correcting the direct current offset parameter of the synchronous feedback signal according to the direct current offset parameter of the transmitting signal to obtain a direct current offset correction parameter of the synchronous feedback signal;
correcting the amplitude imbalance parameter of the synchronous feedback signal according to the amplitude imbalance parameter of the transmitting signal to obtain an amplitude imbalance correction parameter of the synchronous feedback signal;
and correcting the phase imbalance parameter of the synchronous feedback signal according to the phase imbalance parameter of the transmitting signal to obtain the phase imbalance correction parameter of the synchronous feedback signal.
The following is detailed with reference to the formula:
the DC offset parameter, the amplitude imbalance parameter, and the phase imbalance parameter of the transmission signal are respectively represented as DC1, IQ1, and PH1, the DC offset parameter, the amplitude imbalance parameter, and the phase imbalance parameter of the synchronous feedback signal are respectively represented as DC2, IQ2, and PH2, and the DC offset correction parameter, the amplitude imbalance correction parameter, and the phase imbalance correction parameter of the synchronous feedback signal are respectively represented as DC, IQ, and PH, then DC2-DC1, IQ2/IQ1, and PH2-PH 1.
And S140, correcting the synchronous feedback signal according to the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal.
S140 specifically includes:
performing direct current offset correction on the I path signal in the synchronous feedback signal according to the I path direct current offset correction parameter in the direct current offset correction parameters to obtain a first corrected I path signal;
correcting the Q-path signal in the synchronous feedback signal according to the Q-path direct current offset correction parameter in the direct current offset correction parameters to obtain a first corrected Q-path signal;
correcting the first corrected I path signal according to the amplitude unbalance correction parameter to obtain a second corrected I path signal;
correcting the first corrected Q path signal according to the second corrected I path signal and the phase unbalance correction parameter to obtain a second corrected Q path signal;
the corrected synchronous feedback signal comprises a second corrected I path signal and a second corrected Q path signal.
This is further illustrated below in connection with the formula.
The dc offset is corrected as follows:
ri(k)＝ri(k)-dc_ri k＝1…K
rq(k)＝rq(k)-dc_rq k＝1…K
the amplitude imbalance is corrected as follows:
ri(k)＝ri(k)·gi k＝1…K
rq(k)＝rq(k) k＝1…K
the phase imbalance is corrected as follows:
ri(k)＝ri(k) k＝1…K
and after the ZIF correction is finished, performing matrix inversion on the feedback signal and the transmitting signal after the ZIF correction to obtain a DPD coefficient, and storing the DPD coefficient in an LUT (look-up table). It should be noted that the ZIF modified feedback signal and the transmission signal may or may not be synchronized in time, and if there is a time delay between them, it indicates that corresponding synchronization processing is required:
converting the modified synchronous feedback signal into a simultaneous feedback signal which is the same as the transmitting signal; and determining a digital pre-distortion (DPD) coefficient according to the simultaneous feedback signal and the transmitting signal.
Assuming that the sampling point range of the corrected synchronous feedback signal y and the transmission signal z is (1: end), after the time delay shift of y and z is obtained, the conversion process is as shown in the following formula:
y＝y(1:end-shift)；
z＝z(shift+1:end)。
referring to fig. 5, a schematic diagram of a complete ZIF modification process in a DPD processing apparatus is shown. The transmission signal output by the DPD processor is a Digital signal, and is transmitted after being amplified by a power amplifier in the form of an Analog signal after being processed by Digital-to-Analog Converter (DAC), radio frequency and the like; after receiving the transmitted analog signal, the receiver correspondingly processes the analog signal and restores the analog signal into a digital signal, and the digital signal is acquired by the data acquisition controller of the receiving end to obtain a feedback signal. After the power of the feedback signal is determined to be within the preset range, the steps from S110 to S140 are executed, that is, the feedback signal is converted into a synchronous feedback signal which is in the same phase and amplitude as the transmitting signal, the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal are calculated, then the synchronous feedback signal is corrected, the correction of the synchronous feedback signal keeps the direct current leakage, the amplitude imbalance and the phase imbalance of the signal, and the problem of excessive correction is solved. And after the correction is finished, converting the synchronous feedback signal into a simultaneous feedback signal with the same time delay as the transmitting signal, determining a digital pre-distortion (DPD) coefficient according to the simultaneous feedback signal and the transmitting signal, and updating an LUT table. And the DPD processor performs predistortion processing on the next input signal according to the updated LUT table to obtain a predistortion transmitting signal which is more in line with the characteristics of the device.
Referring to fig. 6, an embodiment of the present invention provides an apparatus for correcting a feedback signal, including:
a first synchronization module 610 for converting the feedback signal into a synchronous feedback signal having the same phase, amplitude and phase as the transmission signal;
a parameter calculating module 620, configured to calculate a dc offset parameter, an amplitude imbalance parameter, and a phase imbalance parameter of the transmission signal and the synchronization feedback signal, respectively;
a parameter correction module 630, configured to correct the dc offset parameter, the amplitude imbalance parameter, and the phase imbalance parameter of the synchronous feedback signal according to the dc offset parameter, the amplitude imbalance parameter, and the phase imbalance parameter of the transmission signal, so as to obtain the dc offset correction parameter, the amplitude imbalance correction parameter, and the phase imbalance correction parameter of the synchronous feedback signal;
the signal correction module 640 is configured to correct the synchronization feedback signal according to a dc offset correction parameter, an amplitude imbalance correction parameter, and a phase imbalance correction parameter of the synchronization feedback signal.
The first synchronization module 610 is specifically configured to:
calculating the time delay between the feedback signal and the transmitting signal, and correcting the feedback signal into a first correction signal according to the time delay;
calculating a phase offset between the feedback signal and the transmission signal, and correcting the first correction signal into a second correction signal according to the phase offset;
and calculating a ratio value between the root mean square of the amplitude of the feedback signal and the root mean square of the amplitude of the transmitting signal, and correcting the second correction signal into the synchronous feedback signal according to the ratio value.
The first synchronization module 610 is configured to calculate a time delay between the feedback signal and the transmission signal, and specifically includes:
determining sampling point positions corresponding to peak values of correlation functions of the feedback signal and the transmitting signal;
and determining the time delay of the feedback signal and the transmitting signal according to the sampling point position corresponding to the peak value of the correlation function of the feedback signal and the transmitting signal.
The first synchronization module 610 is configured to calculate a phase offset between the feedback signal and the transmission signal, and specifically includes:
determining a phase corresponding to a peak value of a correlation function of the feedback signal and the transmission signal;
and determining the phase deviation of the feedback signal and the transmitting signal according to the phase corresponding to the peak value of the correlation function of the feedback signal and the transmitting signal.
Preferably, the apparatus further comprises:
and the power determining module is used for determining that the power of the feedback signal is in a preset range.
The parameter modification module 630 is specifically configured to:
determining a difference value between the direct current offset parameter of the synchronous feedback signal and the direct current offset parameter of the transmitting signal as a direct current offset correction parameter of the synchronous feedback signal;
determining the ratio of the amplitude imbalance parameter of the synchronous feedback signal to the amplitude imbalance parameter of the transmitting signal as the amplitude imbalance correction parameter of the synchronous feedback signal;
and determining the difference value of the phase unbalance parameter of the synchronous feedback signal and the phase unbalance parameter of the transmitting signal as the phase unbalance correction parameter of the synchronous feedback signal.
The signal modification module 640 is specifically configured to:
performing direct current offset correction on the I path signal in the synchronous feedback signal according to the I path direct current offset correction parameter in the direct current offset correction parameters to obtain a first corrected I path signal;
correcting the Q-path signal in the synchronous feedback signal according to the Q-path direct current offset correction parameter in the direct current offset correction parameters to obtain a first corrected Q-path signal;
correcting the first corrected I path signal according to the amplitude unbalance correction parameter to obtain a second corrected I path signal;
correcting the first corrected Q path signal according to the second corrected I path signal and the phase unbalance correction parameter to obtain a second corrected Q path signal;
the corrected synchronous feedback signal comprises a second corrected I path signal and a second corrected Q path signal.
Preferably, the apparatus further comprises:
a second synchronization module, configured to convert the modified synchronization feedback signal into a simultaneous feedback signal that is the same as the transmission signal;
and determining a digital pre-distortion (DPD) coefficient according to the simultaneous feedback signal and the transmitting signal.
In summary, embodiments of the present invention provide a method and an apparatus for correcting a feedback signal, so that a synchronous feedback signal is corrected only by correcting dc leakage, amplitude imbalance and phase imbalance caused by a ZIF architecture, the dc leakage, amplitude imbalance and phase imbalance of the signal itself are retained, the problem of over-correction is solved, and the effect of DPD is further ensured.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (16)
1. A method for modifying a feedback signal, comprising:
converting the feedback signal into a synchronous feedback signal which is at the same time, in phase and at the same amplitude as the transmitting signal;
respectively calculating direct current offset parameters, amplitude imbalance parameters and phase imbalance parameters of the transmitting signals and the synchronous feedback signals;
correcting the direct current bias parameter, the amplitude imbalance parameter and the phase imbalance parameter of the synchronous feedback signal according to the direct current bias parameter, the amplitude imbalance parameter and the phase imbalance parameter of the transmitting signal to obtain a direct current bias correction parameter, an amplitude imbalance correction parameter and a phase imbalance correction parameter of the synchronous feedback signal;
and correcting the synchronous feedback signal according to the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal.
2. The method of claim 1, wherein converting the feedback signal to a synchronous feedback signal that is simultaneous, in-phase, and of the same magnitude as the transmit signal comprises:
calculating the time delay between the feedback signal and the transmitting signal, and correcting the feedback signal into a first correction signal according to the time delay;
calculating a phase offset between the feedback signal and the transmission signal, and correcting the first correction signal into a second correction signal according to the phase offset;
and calculating a ratio value between the root mean square of the amplitude of the feedback signal and the root mean square of the amplitude of the transmitting signal, and correcting the second correction signal into the synchronous feedback signal according to the ratio value.
3. The method of claim 2, wherein calculating the time delay between the feedback signal and the transmit signal comprises:
determining sampling point positions corresponding to peak values of correlation functions of the feedback signal and the transmitting signal;
and determining the time delay of the feedback signal and the transmitting signal according to the sampling point position corresponding to the peak value of the correlation function of the feedback signal and the transmitting signal.
4. The method of claim 2, wherein calculating the phase offset between the feedback signal and the transmit signal comprises:
determining a phase corresponding to a peak value of a correlation function of the feedback signal and the transmission signal;
and determining the phase deviation of the feedback signal and the transmitting signal according to the phase corresponding to the peak value of the correlation function of the feedback signal and the transmitting signal.
5. The method of claim 1, wherein prior to converting the feedback signal to a synchronous feedback signal that is simultaneous, in-phase, and of the same magnitude as the transmit signal, further comprising:
determining that the power of the feedback signal is within a preset range.
6. The method of claim 1, wherein the step of correcting the dc offset parameter, the amplitude imbalance parameter, and the phase imbalance parameter of the synchronization feedback signal according to the dc offset parameter, the amplitude imbalance parameter, and the phase imbalance parameter of the transmission signal to obtain the dc offset correction parameter, the amplitude imbalance correction parameter, and the phase imbalance correction parameter of the synchronization feedback signal comprises:
determining a difference value between the direct current offset parameter of the synchronous feedback signal and the direct current offset parameter of the transmitting signal as a direct current offset correction parameter of the synchronous feedback signal;
determining the ratio of the amplitude imbalance parameter of the synchronous feedback signal to the amplitude imbalance parameter of the transmitting signal as the amplitude imbalance correction parameter of the synchronous feedback signal;
and determining the difference value of the phase unbalance parameter of the synchronous feedback signal and the phase unbalance parameter of the transmitting signal as the phase unbalance correction parameter of the synchronous feedback signal.
7. The method of claim 1, wherein modifying the synchronization feedback signal based on the dc offset correction parameter, the amplitude imbalance correction parameter, and the phase imbalance correction parameter of the synchronization feedback signal comprises:
performing direct current offset correction on the I path signal in the synchronous feedback signal according to the I path direct current offset correction parameter in the direct current offset correction parameters to obtain a first corrected I path signal;
correcting the Q-path signal in the synchronous feedback signal according to the Q-path direct current offset correction parameter in the direct current offset correction parameters to obtain a first corrected Q-path signal;
correcting the first corrected I path signal according to the amplitude unbalance correction parameter to obtain a second corrected I path signal;
correcting the first corrected Q path signal according to the second corrected I path signal and the phase unbalance correction parameter to obtain a second corrected Q path signal;
the corrected synchronous feedback signal comprises a second corrected I path signal and a second corrected Q path signal.
8. The method of claim 1, wherein after correcting the synchronization feedback signal according to the dc offset correction parameter, the amplitude imbalance correction parameter, and the phase imbalance correction parameter of the synchronization feedback signal, further comprising:
converting the modified synchronous feedback signal into a simultaneous feedback signal which is the same as the transmitting signal;
and determining a digital pre-distortion (DPD) coefficient according to the simultaneous feedback signal and the transmitting signal.
9. An apparatus for modifying a feedback signal, comprising:
the first synchronization module is used for converting the feedback signal into a synchronous feedback signal which is at the same time, in phase and at the same amplitude as the transmitting signal;
the parameter calculation module is used for calculating a direct current offset parameter, an amplitude imbalance parameter and a phase imbalance parameter of the transmitting signal and the synchronous feedback signal respectively;
the parameter correction module is used for correcting the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the synchronous feedback signal according to the direct current offset parameter, the amplitude imbalance parameter and the phase imbalance parameter of the transmitting signal to obtain the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal;
and the signal correction module is used for correcting the synchronous feedback signal according to the direct current offset correction parameter, the amplitude imbalance correction parameter and the phase imbalance correction parameter of the synchronous feedback signal.
10. The apparatus of claim 9, wherein the first synchronization module is specifically configured to:
calculating the time delay between the feedback signal and the transmitting signal, and correcting the feedback signal into a first correction signal according to the time delay;
calculating a phase offset between the feedback signal and the transmission signal, and correcting the first correction signal into a second correction signal according to the phase offset;
and calculating a ratio value between the root mean square of the amplitude of the feedback signal and the root mean square of the amplitude of the transmitting signal, and correcting the second correction signal into the synchronous feedback signal according to the ratio value.
11. The apparatus of claim 10, wherein the first synchronization module, when configured to calculate the time delay between the feedback signal and the transmit signal, specifically comprises:
determining sampling point positions corresponding to peak values of correlation functions of the feedback signal and the transmitting signal;
and determining the time delay of the feedback signal and the transmitting signal according to the sampling point position corresponding to the peak value of the correlation function of the feedback signal and the transmitting signal.
12. The apparatus of claim 10, wherein the first synchronization module is configured to calculate a phase offset between the feedback signal and the transmit signal, and specifically comprises:
determining a phase corresponding to a peak value of a correlation function of the feedback signal and the transmission signal;
and determining the phase deviation of the feedback signal and the transmitting signal according to the phase corresponding to the peak value of the correlation function of the feedback signal and the transmitting signal.
13. The apparatus of claim 9, further comprising:
and the power determining module is used for determining that the power of the feedback signal is in a preset range.
14. The apparatus of claim 9, wherein the parameter modification module is specifically configured to:
determining a difference value between the direct current offset parameter of the synchronous feedback signal and the direct current offset parameter of the transmitting signal as a direct current offset correction parameter of the synchronous feedback signal;
determining the ratio of the amplitude imbalance parameter of the synchronous feedback signal to the amplitude imbalance parameter of the transmitting signal as the amplitude imbalance correction parameter of the synchronous feedback signal;
and determining the difference value of the phase unbalance parameter of the synchronous feedback signal and the phase unbalance parameter of the transmitting signal as the phase unbalance correction parameter of the synchronous feedback signal.
15. The apparatus of claim 9, wherein the signal modification module is specifically configured to:
performing direct current offset correction on the I path signal in the synchronous feedback signal according to the I path direct current offset correction parameter in the direct current offset correction parameters to obtain a first corrected I path signal;
correcting the Q-path signal in the synchronous feedback signal according to the Q-path direct current offset correction parameter in the direct current offset correction parameters to obtain a first corrected Q-path signal;
correcting the first corrected I path signal according to the amplitude unbalance correction parameter to obtain a second corrected I path signal;
correcting the first corrected Q path signal according to the second corrected I path signal and the phase unbalance correction parameter to obtain a second corrected Q path signal;
the corrected synchronous feedback signal comprises a second corrected I path signal and a second corrected Q path signal.
16. The apparatus of claim 9, further comprising:
a second synchronization module, configured to convert the modified synchronization feedback signal into a simultaneous feedback signal that is the same as the transmission signal;
and determining a digital pre-distortion (DPD) coefficient according to the simultaneous feedback signal and the transmitting signal.
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