An envelope shaping method based on power electronics steering in envelope tracking power supply

Abstract

This invention discloses an envelope shaping method based on power electronics guidance for envelope tracking power supplies. The method includes: acquiring the envelope of the radio frequency signal to be tracked and extracting its peak and valley feature points; introducing a reference level protection that satisfies the power amplifier's inflection point voltage constraint; designing an adaptive hardware response limit based on the switching device speed and filter response capability to filter feature points in the high-frequency fluctuation region; when the peak points show an increasing or decreasing trend, if the time interval between a feature point and an adjacent peak point is less than the hardware response limit, then the corresponding switch control transition is blocked. The technical solution provided by this invention can effectively compress the equivalent bandwidth of the envelope signal, reduce the switching frequency of the switching devices, avoid linearity degradation caused by the shaped envelope being lower than the original envelope, and achieve a balance between signal synchronization and algorithm delay. It is suitable for optimizing the power supply efficiency of power amplifiers for high-dynamic, wideband wireless communication.

Description

Technical Field

[0001] This invention relates to the technical field of envelope signal processing, specifically to an envelope shaping method based on power electronics guidance for envelope tracking power supplies. Background Technology

[0002] With the continuous improvement of my country's new-generation information and communication infrastructure, broadband wireless transmission systems are rapidly evolving towards higher bandwidth, higher spectral efficiency, and more complex modulation schemes. By the end of 2025, my country had built 4.838 million 5G base stations, achieving 5G coverage in all townships and over 95% of administrative villages nationwide. The 5G-A network has covered more than 330 cities, and the number of 5G mobile phone users has reached 1.204 billion. With the rapid development of mobile communication systems, the energy consumption of radio frequency power amplifiers in base stations, mobile terminals, and various wireless transmission equipment has become increasingly prominent. Especially in 5G and subsequent broadband communication systems, peak-to-average power ratio (PAPR) modulation signals such as Orthogonal Frequency Division Multiplexing (OFDM) are widely used. These signals are characterized by severe envelope fluctuations, large dynamic range, and high instantaneous peak values, causing power amplifiers to operate in a backoff state far from saturation most of the time, resulting in a significant decrease in average efficiency.

[0003] Envelope tracking (ET) technology has garnered significant attention for improving the efficiency of radio frequency (RF) power amplifiers. This technology dynamically adjusts the power amplifier's supply voltage according to the envelope of the input signal, enabling the amplifier to maintain high efficiency under varying output power conditions. Compared to fixed power supply methods, envelope tracking significantly reduces system power consumption while maintaining a certain level of linearity, thus holding significant application value in high-efficiency RF transmitters.

[0004] However, in practical applications, the original envelope signal usually contains many high-frequency components and exhibits numerous rapid fluctuations, spikes, and narrow pulse changes. This places high demands on the dynamic response speed, bandwidth capability, and stability of the envelope tracking power supply. Directly using the original envelope signal to drive the envelope tracking power supply can easily lead to the following problems: First, the envelope bandwidth is too wide, exceeding the dynamic adjustment capability achievable by the power electronic converter, resulting in increased power supply tracking error. Second, the presence of numerous short-term spikes and ineffective valleys in the envelope can easily cause frequent high-speed adjustments of the power supply, increasing switching losses and control complexity. Third, when the envelope voltage is too low, the power amplifier may enter the low-efficiency region or even the nonlinear operating region, affecting the RF output performance.

[0005] In existing technologies, low-pass filtering, amplitude limiting and shaping, and delay compensation are commonly used to process the envelope signal in order to reduce the envelope bandwidth and improve the feasibility of envelope tracking power supply. Although the above methods can suppress high-frequency components or reduce the dynamic range of the envelope to a certain extent, they still have the following shortcomings: First, simple low-pass filtering can easily weaken key peak information and affect the linearity of the power amplifier; second, although simple amplitude limiting can raise the low voltage region, it is difficult to balance peak preservation and valley optimization; third, most existing shaping strategies directly smooth the waveform as a whole, lacking targeted utilization of peak points, valley points, and time-domain evolution characteristics, which may lead to unnecessary local fluctuations in the shaped envelope or insufficient power supply due to over-shaping.

[0006] Furthermore, envelope tracking power supplies are essentially power electronic power supply systems, and their dynamic characteristics, switching frequency limitations, control bandwidth, and output stability are all closely related to the envelope characteristics on the communication side. If the envelope shaping process does not fully consider the constraints of power electronic implementation, even if a relatively smooth waveform is obtained at the signal processing level, problems such as tracking lag, increased ripple, or control instability may occur in actual power supply driving. Therefore, how to effectively shape the original envelope while ensuring the normal operation of the power amplifier, combined with power electronic supply constraints, to reduce invalid dynamic fluctuations, compress bandwidth, and prevent the shaped envelope from being lower than the original envelope signal, has become an important research direction in envelope tracking technology.

[0007] Therefore, it is necessary to propose an envelope shaping method for envelope tracking power supplies to solve the problems of excessively wide envelope bandwidth, numerous local spikes and invalid valleys, low voltage regions that are not conducive to the stable operation of power amplifiers, and insufficient power supply after shaping in the existing technology. Summary of the Invention

[0008] The purpose of this invention is to propose an envelope shaping method based on power electronics guidance for envelope tracking power supplies, thereby solving the problems of excessively wide envelope bandwidth, numerous local spikes and invalid valleys, low voltage regions that are not conducive to the stable operation of power amplifiers, and insufficient power supply after shaping in the prior art.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] First, the original envelope signal is acquired and normalized. A minimum voltage threshold is set based on the power amplifier's extremely low voltage operating constraint. Envelope samples below this threshold are clamped to obtain a preprocessed envelope signal. Next, local extremum detection is performed on the preprocessed envelope signal to extract the amplitude and location index information of peak and valley points. Based on this, all peak points are retained, and valley points are filtered according to the amplitude variation trend of adjacent peak points on both sides of a valley point and the time interval between the valley point and its adjacent peak points to obtain effective valley points. Then, all peak points are merged with the filtered effective valley points to construct a set of key control points. Based on this set of key control points, the envelope signal is interpolated and reconstructed on a complete time axis to obtain a preliminary shaped envelope signal. Then, the preliminary shaped envelope signal is compared point-by-point with the original envelope signal, and the portion below the original envelope signal is compensated and corrected to obtain the target shaped envelope signal. Finally, the target shaped envelope signal is output to the envelope tracking power supply for controlling the dynamic power supply of the power amplifier.

[0011] As an improvement of the present invention, in another embodiment, the set of key control points can also be determined by a recursive coverage detection method: Specifically, the search window length is set, and the number of sampling points corresponding to each search window is determined according to the sampling frequency; candidate peak points are searched within the search window, and one or more candidate peak points are selected as support points according to their amplitude; at the same time, local maximum values ​​are searched in the starting area of ​​the search window as boundary compensation points to reduce peak omissions at the window boundary; subsequently, a piecewise linear envelope is constructed based on the current set of support points, and it is determined whether there are sampling points in the original envelope signal that are higher than the piecewise linear envelope; if so, the sampling point with the largest excess is added as a new support point to the support point set, and the piecewise linear envelope is reconstructed; the above process is repeated until the piecewise linear envelope satisfies the coverage constraint, and the target shaped envelope obtained thereby can reduce unnecessary high-frequency fluctuations and short-term oscillations while ensuring that it is not lower than the original envelope signal.

[0012] As an improvement of the present invention, when the normalized envelope sample value is less than the preset minimum voltage threshold, the envelope sample value is set to the minimum voltage threshold; when the normalized envelope sample value is greater than or equal to the minimum voltage threshold, the envelope sample value is kept unchanged. Through the above processing, the power amplifier can be prevented from entering the extremely low voltage operating region, thereby improving the efficiency and linear operating state of the power amplifier, and reducing the risk of control instability of the envelope tracking power supply in the low voltage region.

[0013] As another improvement of the present invention, the local extreme value detection is achieved by comparing the amplitude of the current sampling point with that of its neighboring sampling points. When the amplitude of the current sampling point is greater than that of its neighboring sampling points, it is determined to be a peak point; when the amplitude of the current sampling point is less than that of its neighboring sampling points, it is determined to be a valley point. By extracting the local features of the envelope, a basis can be provided for subsequent key point screening and reconstruction.

[0014] As another improvement of the present invention, the criteria for determining the "upward trend" and "downward trend" are as follows: when a valley point is located between two peak points, and the amplitude of the latter peak point is greater than the amplitude of the former peak point, the time interval between the valley point and the former peak point is used as the determination criterion; when the amplitude of the latter peak point is less than the amplitude of the former peak point, the time interval between the valley point and the latter peak point is used as the determination criterion; when the time interval is greater than a preset time threshold, the valley point is retained; otherwise, the valley point is discarded. In this way, while maintaining the main envelope change trend, invalid valley points that contribute little to power dynamic tracking can be removed, reducing unnecessary local fluctuations during the shaping process.

[0015] As another improvement of the present invention, the starting valley point and the ending valley point can be filtered according to the time interval between them and the adjacent peak point; when the time interval is greater than a preset time threshold, the corresponding boundary valley point is retained. This can improve the completeness and accuracy of the boundary position envelope reconstruction.

[0016] As another improvement of the present invention, the set of key control points can also be constructed by window search; specifically, candidate peak points are extracted within a preset search window, and candidate peak points with larger amplitudes are selected as support points; at the same time, boundary compensation points can be set in the window boundary area to reduce the omission of local peaks and improve the continuity of envelope reconstruction.

[0017] As another improvement of the present invention, the envelope reconstruction can also adopt a recursive coverage detection method; specifically, the reconstructed line segment between adjacent support points is compared with the original envelope point by point. When the original envelope is higher than the reconstructed line segment, the sampling point with the largest excess is added as a new support point, and the envelope reconstruction is performed again until the reconstructed envelope satisfies the coverage constraint.

[0018] As another improvement of the present invention, an amplitude margin coefficient can be introduced into the target shaped envelope signal; by applying an amplitude margin coefficient of not less than 1 to the reconstructed envelope that satisfies the coverage constraint, the device voltage drop, control delay and tracking error can be compensated, and the risk of instantaneous power supply insufficiency of the power amplifier can be reduced.

[0019] As another improvement of the present invention, the target shaped envelope signal satisfies:

[0020]

[0021] in, The original envelope signal, This is a preliminary shaping envelope signal. The target is to shape the envelope signal. Through this compensation and correction mechanism, the shaped envelope can be prevented from being lower than the power supply requirement, thereby preventing the power amplifier from experiencing gain compression, linear distortion or output degradation due to insufficient power supply.

[0022] As another improvement of the present invention, the target shaped envelope signal satisfies the following: an amplitude margin coefficient is applied to the reconstructed envelope signal that satisfies the coverage constraint. The target shaped envelope signal is obtained:

[0023]

[0024] in, To reconstruct the envelope signal that satisfies the coverage constraint, The amplitude margin coefficient is used to compensate for the power supply margin requirements caused by the tracking error of the envelope tracking power supply, device voltage drop, or control delay.

[0025] As an improvement of the present invention, the method for detecting local peak points and local valley points in the preprocessed envelope signal includes:

[0026] Local extreme points are identified based on the amplitude change relationship between the current sampling point and its adjacent sampling points. When the amplitude of the current sampling point is greater than the amplitude of its adjacent sampling points, the current sampling point is determined as a local peak point. When the amplitude of the current sampling point is less than the amplitude of its adjacent sampling points, the current sampling point is determined as a local valley point. The amplitude information and location index information corresponding to the local peak point and the local valley point are recorded.

[0027] The hardware response limit The hardware response limit is determined based on at least one of the following: switching time of the switching device, filter response rate, allowable rate of change of inductor current, and system control cycle. Used to characterize the minimum time response interval that an envelope tracking power source can achieve during a single dynamic adjustment process.

[0028] As an improvement to the present invention, the screening in step S3 further includes a hardware response limit. Peak-valley time constraint filtering, the hardware response limit-based Peak-valley time constraint screening includes:

[0029] For a local valley point located between two adjacent local peak points, determine the amplitude change relationship between the latter local peak point and the former local peak point;

[0030] When the amplitude of the next local peak point is greater than the amplitude of the previous local peak point, it is determined that the overall envelope of the interval is in an upward trend, and the time interval between the local valley point and the previous local peak point is used as the screening criterion.

[0031] When the amplitude of the next local peak point is less than that of the previous local peak point, it is determined that the overall envelope of the interval is in a downward trend, and the time interval between the local valley point and the next local peak point is used as the screening criterion.

[0032] When the time interval is less than the hardware response limit When the time interval is greater than or equal to the hardware response limit, discard the corresponding local valley point; When this happens, the corresponding local valley point is retained.

[0033] As an improvement of the present invention, the time interval between the local valley point and the adjacent local peak point is calculated based on the difference in their location indices and the sampling frequency, and the relationship is as follows:

[0034]

[0035] in, For time intervals, This is the location index of the local valley point. For the position index of adjacent local peak points, The sampling frequency.

[0036] As an improvement of the present invention, the discarding of the corresponding local valley point includes:

[0037] During the envelope shaping process, the local valley point is not used as a key control point in waveform reconstruction to suppress the short-term envelope dip and corresponding switching control jump caused by the local valley point, thereby reducing the number of ineffective dynamic adjustments of the envelope tracking power supply.

[0038] As an improvement of the present invention, the hardware response limit is mentioned. Peak-valley time constraint filtering also includes boundary valley point filtering:

[0039] For a local valley point at the beginning, the judgment is based on the time interval between it and the next local peak point; for a local valley point at the end, the judgment is based on the time interval between it and the previous local peak point; when the time interval is greater than or equal to the hardware response limit... If the corresponding boundary local valley value is retained, the corresponding boundary local valley value is discarded.

[0040] As an improvement to the present invention, the recursive support point selection based on coverage error includes:

[0041] Set the search window length And according to the sampling frequency The search window length is converted into the corresponding number of sampling points. The relationship is as follows:

[0042]

[0043] Since the actual window length must not be less than the set minimum response time, the number of sampling points needs to be rounded up, and candidate local peak points are searched within each search window. The starting point of the search window and the candidate local peak points are then used as the current set of support points.

[0044] Wherein, the search window length It is determined based on at least one of the following: minimum response time of the envelope tracking power supply, allowable switching frequency of the switching device, rate of change of inductor current, or control delay.

[0045] As an improvement of the present invention, the candidate local peak points are identified by the difference sign change between adjacent sampling points:

[0046] When the amplitude change of the preceding adjacent interval of a certain sampling point shows an upward trend, and the amplitude change of the following adjacent interval shows a downward or flat trend, the sampling point is determined as a candidate local peak point.

[0047] As an improvement of the present invention, within each search window, candidate local peak points are sorted according to their amplitude, and one or more candidate local peak points with larger amplitudes are selected as support points to construct a piecewise linear envelope.

[0048] As an improvement of the present invention, a local maximum value is searched within the starting area of ​​each search window as a boundary compensation point, and the boundary compensation point is added to the current support point set to reduce the coverage deficiency caused by the omission of candidate peak points at the window boundary position.

[0049] As an improvement to the present invention, the recursive support point screening based on coverage error further includes a coverage error detection step:

[0050] A linear reconstruction segment is constructed between two adjacent support points, and the linear reconstruction segment is compared point by point with the original envelope signal in the corresponding interval to calculate the coverage error.

[0051]

[0052] in, The original envelope signal, This is the envelope value corresponding to the current linear reconstruction segment;

[0053] When it exists When the number of sampling points exceeds the preset error threshold, the sampling point with the largest coverage error is selected as a new support point and added to the current support point set. The current support point set is then reordered and linear reconstruction is performed again.

[0054] Repeat the process of coverage error detection, adding new support points and linear reconstruction until the original envelope signal is no higher than the corresponding linear reconstruction segment in each linear reconstruction segment, or the maximum coverage error is no greater than the preset error threshold.

[0055] As an improvement of the present invention, the waveform reconstruction in step S4 adopts any one of linear interpolation, spline interpolation or polynomial interpolation.

[0056] As an improvement of the present invention, the method further includes interpolation filtering and smoothing of the target shaped envelope signal to suppress high-frequency components, reduce rapid envelope fluctuations and limit envelope bandwidth, thereby reducing the dynamic response pressure of the envelope tracking power supply.

[0057] As an improvement of the present invention, the interpolation filtering is implemented using a finite impulse response (FIR) filter, which is used to suppress the spectral image components generated during the interpolation process.

[0058] As an improvement of the present invention, the FIR filter is a low-pass filter, the cutoff frequency of which is set according to the interpolation factor, and the filter order is selected according to the stopband attenuation requirements, so as to reduce the bandwidth of the target shaping envelope signal and improve the dynamic realizability of the envelope tracking power supply.

[0059] As an improvement of the present invention, it further includes slope analysis of the preliminary shaped envelope signal or the target shaped envelope signal. The slope analysis is calculated based on the amplitude difference between adjacent sampling points and the sampling time interval, and the relationship is as follows:

[0060]

[0061] in, Let the slope be the envelope slope. The envelope amplitude corresponding to the current sampling point. The envelope amplitude corresponding to the previous sampling point. The sampling time interval;

[0062] The slope analysis includes a preset maximum slew rate in the hardware. The preset maximum slew rate of the hardware The preset maximum slew rate is determined based on at least one of the following: switching device response time, drive circuit delay, equivalent inductance parameters, load characteristics, and system sampling period. Used to characterize the maximum allowable rate of amplitude change of the target shaped envelope signal between adjacent sampling points;

[0063] Based on the slope analysis results, select the inductor parameters, inductor branches, or inductor combinations in the envelope tracking power supply so that the output current variation capability of the envelope tracking power supply matches the variation trend of the target shaped envelope signal.

[0064] As an improvement of the present invention, if the envelope slope Exceeding the preset maximum slew rate of the hardware Then, by adjusting the amplitude difference or time interval between adjacent key control points, the reconstructed envelope slope can satisfy the maximum slew rate constraint of the hardware.

[0065] Compared with the prior art, the beneficial effects of the present invention are:

[0066] 1. This invention clamps the original envelope by setting a minimum voltage threshold, preventing the power amplifier from entering the extremely low voltage operating region, thereby improving the stability and feasibility of the power amplifier power supply process.

[0067] 2. This invention does not simply smooth the original envelope as a whole, but rather constructs a set of key control points by retaining all peak points and filtering valley points according to time constraints. This can reduce invalid valleys and minor fluctuations while preserving the main envelope evolution trend.

[0068] 3. By interpolating and reconstructing key control points, this invention can effectively compress the invalid high-frequency components of the original envelope, reduce the dynamic bandwidth requirements of the envelope tracking power supply, and decrease control complexity and switching losses.

[0069] This invention ensures that the target shaped envelope is not lower than the power supply requirement by setting a compensation mechanism for the lower bound of the original envelope, thus avoiding the problem of insufficient power supply caused by over-shaping, thereby balancing the efficiency and linear performance of the power amplifier.

[0070] 4. This invention constructs an envelope support point set through a recursive coverage detection method, which can directly discover and supplement overshoot points that may lead to underpowerment during the envelope reconstruction process, ensuring that the target shaped envelope is not lower than the original envelope in the entire time domain, thereby improving the safety of dynamic power supply of the power amplifier.

[0071] 5. This invention adjusts the support point density and power supply safety margin by using a search window and amplitude margin coefficient, which can strike a balance between envelope coverage accuracy, shaping smoothness and algorithm complexity, and is suitable for envelope tracking power supply systems with different bandwidths, modulation methods and hardware response capabilities.

[0072] 6. This invention combines communication envelope characteristics with power electronic power supply constraints, and is suitable for envelope tracking power supply control under broadband, peak-to-average power ratio signal driving conditions, and has good engineering application value. Attached Figure Description

[0073] Figure 1 This is a flowchart of the envelope shaping method based on power electronics guidance used in envelope tracking power supplies according to the present invention.

[0074] Figure 2 This is a time-domain comparison diagram of the original envelope signal and the target shaped envelope signal of this invention;

[0075] Figure 3 This is a diagram illustrating the effect of the support point selection and envelope reconstruction based on recursive coverage detection of the present invention. Detailed Implementation

[0076] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0077] Example

[0078] This invention proposes a power electronics-guided envelope shaping method for envelope tracking power supplies. This method is mainly applicable to the dynamic power supply control of power amplifiers in broadband radio frequency transmission systems, especially for peak-to-average power ratio (PAPR) signal scenarios such as OFDM. By performing low-voltage constraint clamping, peak-valley feature extraction, effective valley value screening, key point reconstruction, and lower bound compensation on the original envelope signal, the method enables the target shaped envelope to meet the power amplifier's power supply requirements while reducing the dynamic adjustment pressure of the envelope tracking power supply and improving system feasibility.

[0079] In this embodiment, the original envelope signal corresponding to the input radio frequency signal is first obtained. This original envelope signal can be obtained by directly taking the absolute value of the radio frequency signal, or it can be extracted through Hilbert transform, envelope detection, or other equivalent methods. To facilitate subsequent processing, the original envelope signal is normalized so that its amplitude is mapped to a preset range. In one specific embodiment, a sampling sequence of a predetermined length is extracted from the original envelope signal for processing, for example, the first 40,000 sampling points are selected as the analysis object. Subsequently, a minimum voltage threshold is set according to the operating constraints of the power amplifier in the extremely low supply voltage region, for example, it can be set to 0.18. When the normalized envelope sample value is lower than the minimum voltage threshold, the envelope sample value is clamped to the minimum voltage threshold; when the normalized envelope sample value is not lower than the minimum voltage threshold, the original value remains unchanged. Through the above processing, excessively low supply voltage output of the envelope tracking power supply can be avoided, preventing the power amplifier from entering the low-efficiency region or nonlinear operating region.

[0080] After clamping, local extremum detection is performed on the preprocessed envelope signal to extract peak and valley points. Specifically, local extremum points can be determined based on the amplitude variation relationship between adjacent sampling points: when the amplitude of a sampling point is greater than the amplitude of its adjacent sampling points, it is identified as a peak point; when the amplitude of a sampling point is less than the amplitude of its adjacent sampling points, it is identified as a valley point. For each detected peak and valley point, its corresponding amplitude information and its position index information in the original sequence are recorded. Through this step, local feature points that can characterize its main evolution trend can be extracted from the continuous envelope signal, providing a basis for subsequent key point screening and envelope reconstruction.

[0081] After extracting peak and valley points, this embodiment retains all peak points and further filters valley points to remove invalid valley points that contribute little to power dynamic tracking. Specifically, for a valley point located between two peak points, the amplitude change trend of the adjacent peak points on both sides of the valley point is first determined. If the amplitude of the latter peak point is greater than that of the former peak point, it indicates that the envelope generally shows an upward trend in this region, and the time interval between the valley point and the former peak point is used as the judgment criterion. If the amplitude of the latter peak point is less than that of the former peak point, it indicates that the envelope generally shows a downward trend in this region, and the time interval between the valley point and the former peak point is used as the judgment criterion. The time interval between subsequent peak points is used as the criterion. When the time interval is greater than a preset time threshold, the valley point is retained; otherwise, the valley point is discarded. In a specific embodiment, the time threshold can be set to 12 sampling intervals. For the boundary valley points at the beginning and end, they can also be filtered according to the time interval between them and the adjacent peak points: if the time interval is greater than the preset time threshold, the corresponding boundary valley point is retained; otherwise, it is discarded. Through this step, while retaining the main envelope change characteristics, fragmented, short-term, and invalid local valley points can be effectively removed, reducing unnecessary fluctuations in the subsequent reconstructed envelope.

[0082] After obtaining all peak points and the selected effective valley points, they are merged to form a set of key control points. Each point in the set of key control points contains amplitude information and location index information. These key points together determine the main evolution contour of the initial shaped envelope. Since all peak points are retained, the main power demand peak in the envelope can be well maintained. The valley points selected through time constraints can reflect the sinking characteristics that are of practical significance to the dynamic trajectory of the power supply, thus taking into account both envelope fidelity and bandwidth compression requirements.

[0083] Based on this, the envelope signal is reconstructed by interpolation on a complete time axis based on the set of key control points to generate a continuous preliminary shaped envelope signal. The interpolation method can be linear interpolation, spline interpolation, or other continuous interpolation methods. In a specific embodiment, linear interpolation is used. According to the position of the key control points in the original time axis, discrete key points are connected into a continuous envelope curve. During the reconstruction process, a complete time axis can be established according to the original sampling rate. For example, when the baseband signal is 200MHz and the subcarrier spacing is 120kHz, the sampling rate is set to 245.76MHz. Then, a corresponding time series is constructed according to the number of sampling points, and the interpolation mapping of key control points is completed on this time axis. Through this interpolation reconstruction step, a continuous, smooth preliminary shaped envelope signal that can reflect the main envelope evolution trend can be recovered from a small number of key control points, thereby reducing the impact of high-frequency fragmented fluctuations in the original envelope on power control.

[0084] Since the preliminary shaped envelope signal after interpolation and reconstruction may be lower than the original envelope signal at some local locations, this embodiment further introduces a lower bound compensation mechanism for the original envelope to avoid insufficient power supply for envelope tracking. Specifically, the preliminary shaped envelope signal and the original envelope signal are compared point by point; when the preliminary shaped envelope signal is lower than the original envelope signal, the original envelope signal is used to compensate for that part; when the preliminary shaped envelope signal is higher than or equal to the original envelope signal, it is kept unchanged. The target shaped envelope signal can be expressed as:

[0085]

[0086] in, Represents the original envelope signal. This represents the initial shaped envelope signal obtained through interpolation and reconstruction. The target shaped envelope signal is represented by the above compensation mechanism, which ensures that the shaped power supply envelope is not lower than the original required envelope, thereby avoiding problems such as under-power supply, gain compression and linear distortion of the power amplifier caused by over-shaping.

[0087] Finally, the final envelope signal obtained after shaping is output to the envelope tracking power supply to control the dynamic power supply of the power amplifier.

[0088] In this embodiment, a method for reconstructing upper envelope support points based on recursive coverage detection is provided to further ensure that the target shaped envelope signal is not lower than the original envelope signal in the entire time domain.

[0089] First, the raw envelope signal of the radio frequency signal to be tracked is acquired, and then based on the sampling frequency... and preset search window length Determine the number of sampling points corresponding to the search window For example, when the sampling frequency is 125MHz and the search window length is 500ns, it can be based on The number of sampling points within each search window is obtained.

[0090] Subsequently, pre-peak identification is performed on the original envelope signal to obtain a global candidate peak point sequence. Peak points can be determined by the difference in sign between adjacent sampling points; that is, when the previous segment of the current sampling point shows an upward trend and the next segment shows a downward or flat trend, the sampling point is determined as a candidate peak point.

[0091] Within each search window, candidate peak points located within the current window range are selected and sorted according to their amplitude. One or more peak points with larger amplitudes are selected as support points. To avoid missing peaks near the starting area of ​​the window, local maximum values ​​can also be searched within the starting area of ​​the search window and added to the candidate support point set as boundary compensation points.

[0092] After obtaining the current set of support points, the support points are sorted in ascending order of time index, and piecewise linear reconstruction segments are constructed between adjacent support points. Then, the piecewise linear reconstruction segments are compared point-by-point with the original envelope signal to calculate the coverage error between them.

[0093]

[0094] in, Represents the original envelope signal. This represents the current piecewise linear reconstruction envelope. If there exists a certain interval... If the sampling point is significantly larger than the current reconstructed envelope at that location, it indicates that the original envelope exceeds the current reconstructed envelope. In this case, the sampling point with the largest coverage error is selected.

[0095]

[0096] The sampling point is then added as a new support point to the current support point set. Subsequently, the support point set is reordered and the piecewise linear reconstruction segment is reconstructed.

[0097] Repeat the above process of coverage error detection, adding support points, and reconstructing until the original envelope signal is no higher than the piecewise linear reconstructed envelope in all reconstruction intervals, or the maximum coverage error is no greater than a preset error threshold. This yields an envelope reconstruction signal that satisfies the coverage constraints.

[0098] Furthermore, an amplitude margin coefficient can be applied to the envelope reconstruction signal that satisfies the coverage constraint. The target shaped envelope signal is obtained:

[0099]

[0100] in, To reconstruct the envelope signal to satisfy coverage constraints, In one specific embodiment, A value of 1.02 can be used to compensate for device voltage drops, control delays, or tracking errors in the envelope tracking power supply.

[0101] By employing the recursive coverage detection method described above, key points that may lead to underpowerment can be proactively identified and supplemented during envelope reconstruction, ensuring that the target shaped envelope is always no lower than the original envelope. Furthermore, because this method prioritizes high-amplitude peak points within each search window and recursively supplements only necessary exceedance points, it can reduce redundant fluctuations while ensuring power supply safety, thereby alleviating the dynamic adjustment pressure on the envelope tracking power supply.

[0102] In summary, compared with existing overall smoothing or simple low-pass filtering methods, the method of this invention, through a combined processing approach of "low voltage threshold clamping—peak-valley feature extraction—effective valley value screening—key point interpolation reconstruction—original envelope lower bound compensation," effectively reduces invalid high-frequency fluctuations and fragmented valley value changes in the original envelope while preserving the power amplifier's power supply requirements as much as possible. This reduces the dynamic adjustment pressure on the envelope tracking power supply and improves system stability and engineering feasibility.

[0103] In the description of this specification, references to terms such as "a specific embodiment," "this embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0104] It should be noted that the minimum voltage threshold, time threshold, number of sampling points, etc., given in the above embodiments are merely exemplary parameters and do not constitute a limitation on the scope of protection of this invention. Those skilled in the art can adjust or replace the relevant parameters according to the specific power amplifier type, envelope tracking power supply topology, signal bandwidth, and control objectives, without departing from the core idea of ​​this invention. For those skilled in the art, several improvements and modifications can be made without departing from the principle of this invention, and all such improvements and modifications fall within the scope of protection of the claims of this invention.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any modifications or equivalent changes made based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A method for envelope shaping based on power electronic guidance in envelope tracking power supplies, characterized in that, Includes the following steps: S1. Obtain the original envelope signal of the radio frequency signal to be tracked, and normalize the original envelope signal; set a minimum voltage threshold according to the knee voltage working constraint of the power amplifier, and perform clamping processing on the envelope sample value below the minimum voltage threshold to obtain the preprocessed envelope signal; S2. Perform feature point detection on the preprocessed envelope signal to obtain a set of candidate feature points, wherein the candidate feature points include local peak points, local valley points, and support points for envelope reconstruction; S3. The candidate feature point set is filtered according to power electronic hardware response constraints to construct a key control point set; wherein, the filtering includes filtering based on hardware response limits. All peak points and some valley points, and recursive support point filtering based on coverage error; S4. Based on the set of key control points, the envelope signal is reconstructed to obtain a preliminary shaped envelope signal; S5. The preliminary shaped envelope signal is compared with the original envelope signal, and the portion lower than the original envelope signal is compensated and corrected, or the preliminary shaped envelope signal is made not lower than the original envelope signal by recursive coverage detection to obtain the target shaped envelope signal. The target shaped envelope signal is used to drive the radio frequency power amplifier in the broadband wireless communication system, and the broadband wireless communication system includes a mobile communication system with a peak-to-average power ratio. S6. Output the target shaping envelope signal to the envelope tracking power supply to control the dynamic power supply of the power amplifier.

2. The envelope shaping method based on power electronic guidance for envelope tracking power supply according to claim 1, characterized in that, In step S1, the clamping process for envelope samples below the minimum voltage threshold is performed as follows: When the normalized envelope sample value is less than the preset minimum voltage threshold, the envelope sample value is set to the minimum voltage threshold; when the normalized envelope sample value is greater than or equal to the minimum voltage threshold, the envelope sample value is kept unchanged. In step S2, the method for detecting local peak points and local valley points in the preprocessed envelope signal includes: Identify local extreme points based on the amplitude variation relationship between the current sampling point and its adjacent sampling points; When the amplitude of the current sampling point is greater than the amplitude of its adjacent sampling points, the current sampling point is determined as a local peak point; when the amplitude of the current sampling point is less than the amplitude of its adjacent sampling points, the current sampling point is determined as a local valley point, and the amplitude information and location index information corresponding to the local peak point and the local valley point are recorded.

3. The envelope shaping method based on power electronic guidance for envelope tracking power supply according to claim 1, characterized in that, The hardware response limit The hardware response limit is determined based on at least one of the following: switching time of the switching device, filter response rate, allowable rate of change of inductor current, and system control cycle. Used to characterize the minimum time response interval that an envelope tracking power supply can achieve during a single dynamic adjustment process; The filtering in step S3 also includes filtering based on hardware response limits. Peak-valley time constraint filtering, the hardware response limit-based Peak-valley time constraint screening includes: For a local valley point located between two adjacent local peak points, determine the amplitude change relationship between the latter local peak point and the former local peak point; When the amplitude of the next local peak point is greater than the amplitude of the previous local peak point, it is determined that the overall envelope of the interval is in an upward trend, and the time interval between the local valley point and the previous local peak point is used as the screening criterion. When the amplitude of the next local peak point is less than that of the previous local peak point, it is determined that the overall envelope of the interval is in a downward trend, and the time interval between the local valley point and the next local peak point is used as the screening criterion. When the time interval is less than the hardware response limit When the time interval is greater than or equal to the hardware response limit, discard the corresponding local valley point; At that time, retain the corresponding local valley point; The time interval between the local valley point and the adjacent local peak point is calculated based on the difference in their location indices and the sampling frequency, and the relationship is as follows: ； in, For time intervals, This is the location index of the local valley point. For the position index of adjacent local peak points, The sampling frequency.

4. The envelope shaping method based on power electronic guidance for envelope tracking power supply according to claim 3, characterized in that, The discarded local valley points include: During the envelope shaping process, the local valley point is not used as a key control point in waveform reconstruction to suppress the short-term envelope dip and corresponding switch control jump caused by the local valley point, thereby reducing the number of ineffective dynamic adjustments of the envelope tracking power supply. The hardware response limit Peak-valley time constraint filtering also includes boundary valley point filtering: For a local valley point at the beginning, the judgment is based on the time interval between it and the next local peak point; for a local valley point at the end, the judgment is based on the time interval between it and the previous local peak point; when the time interval is greater than or equal to the hardware response limit... If the corresponding boundary local valley value is retained, the corresponding boundary local valley value is discarded.

5. The envelope shaping method based on power electronic guidance for envelope tracking power supply according to claim 1, characterized in that, The recursive support point selection based on coverage error includes: Set the search window length And according to the sampling frequency The search window length is converted into the corresponding number of sampling points. The relationship is as follows: ； Since the actual window length must not be less than the set minimum response time, the number of sampling points needs to be rounded up, and candidate local peak points are searched within each search window. The starting point of the search window and the candidate local peak points are then used as the current set of support points. Wherein, the search window length Determined based on at least one of the following: minimum response time of envelope tracking power supply, allowable switching frequency of switching device, rate of change of inductor current, or control delay; Within each search window, candidate local peak points are sorted according to their amplitude, and one or more candidate local peak points with larger amplitudes are selected as support points to construct a piecewise linear envelope. In the initial region of each search window, a local maximum value is searched as a boundary compensation point, and the boundary compensation point is added to the current support point set to reduce the insufficient coverage caused by the omission of candidate peak points at the window boundary position. The candidate local peak points are identified by the difference in sign between adjacent sampling points: When the amplitude change of the preceding adjacent interval of a certain sampling point shows an upward trend, and the amplitude change of the following adjacent interval shows a downward or flat trend, the sampling point is determined as a candidate local peak point. The recursive support point screening based on coverage error also includes a coverage error detection step: A linear reconstruction segment is constructed between two adjacent support points, and the linear reconstruction segment is compared point by point with the original envelope signal in the corresponding interval to calculate the coverage error. ； in, The original envelope signal, This is the envelope value corresponding to the current linear reconstruction segment; When it exists When the number of sampling points exceeds the preset error threshold, the sampling point with the largest coverage error is selected as a new support point and added to the current support point set. The current support point set is then reordered and linear reconstruction is performed again. Repeat the process of coverage error detection, adding new support points and linear reconstruction until the original envelope signal is no higher than the corresponding linear reconstruction segment in each linear reconstruction segment, or the maximum coverage error is no greater than the preset error threshold.

6. The envelope shaping method based on power electronic guidance for envelope tracking power supply according to claim 1, characterized in that, The target shaped envelope signal is obtained through any of the following methods: First, the preliminary shaped envelope signal is compared point by point with the original envelope signal, and compensation and correction are performed according to the following relationship: ； in, The original envelope signal, This is a preliminary shaping envelope signal. The target is the shaped envelope signal; Secondly, an amplitude margin coefficient is applied to the reconstructed envelope signal that satisfies the coverage constraint. The target shaped envelope signal is obtained: ； in, To reconstruct the envelope signal that satisfies the coverage constraint, The amplitude margin coefficient is used to compensate for the power supply margin requirements caused by the tracking error of the envelope tracking power supply, device voltage drop, or control delay.

7. The envelope shaping method based on power electronic guidance for envelope tracking power supply according to claim 1, characterized in that, It also includes interpolation filtering and smoothing of the target shaped envelope signal to suppress high-frequency components, reduce rapid envelope fluctuations and limit envelope bandwidth, thereby reducing the dynamic response pressure of the envelope tracking power supply.

8. The envelope shaping method based on power electronic guidance for envelope tracking power supply according to claim 7, characterized in that, The interpolation filtering is implemented using a finite impulse response (FIR) filter, which is used to suppress the spectral image components generated during the interpolation process. The FIR filter is a low-pass filter, and its cutoff frequency is set according to the interpolation factor. The filter order is selected according to the stopband attenuation requirements to reduce the bandwidth of the target shaping envelope signal and improve the dynamic feasibility of the envelope tracking power supply.

9. The envelope shaping method based on power electronic guidance for envelope tracking power supply according to claim 1, characterized in that, The method also includes slope analysis of the preliminary shaped envelope signal or the target shaped envelope signal. The slope analysis is calculated based on the amplitude difference between adjacent sampling points and the sampling time interval, and the relationship is as follows: ； in, Let the slope be the envelope slope. The envelope amplitude corresponding to the current sampling point. The envelope amplitude corresponding to the previous sampling point. The sampling time interval; The slope analysis includes a preset maximum slew rate in the hardware. The preset maximum slew rate of the hardware The preset maximum slew rate is determined based on at least one of the following: switching device response time, drive circuit delay, equivalent inductance parameters, load characteristics, and system sampling period. Used to characterize the maximum allowable rate of amplitude change of the target shaped envelope signal between adjacent sampling points; Based on the slope analysis results, select the inductor parameters, inductor branches, or inductor combinations in the envelope tracking power supply so that the output current variation capability of the envelope tracking power supply matches the variation trend of the target shaped envelope signal.

10. The envelope shaping method based on power electronic guidance for envelope tracking power supply according to claim 9, characterized in that, If the envelope slope Exceeding the preset maximum slew rate of the hardware Then, by adjusting the amplitude difference or time interval between adjacent key control points, the reconstructed envelope slope can satisfy the maximum slew rate constraint of the hardware.

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