A crest factor reduction method and apparatus based on peak type
By determining the peak type and selecting suitable base pulses and filter coefficients, combined with hard clipping, efficient peak factor reduction without multiple iterations is achieved, improving the spectral performance of the signal.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HENGXUAN TECH (BEIJING) CO LTD
- Filing Date
- 2025-05-30
- Publication Date
- 2026-06-19
AI Technical Summary
Existing peak factor reduction methods based on peak cancellation require multiple iterative calculations, resulting in significant computational overhead.
The peak type is determined based on the magnitude of the in-phase orthogonal signal and a preset threshold. The appropriate base pulse and filter coefficients are selected, the peak clipping pulse is calculated, and combined with hard clipping, to achieve single-pass peak clipping.
This reduces computational load, decreases system latency, and improves peak clipping, ensuring the signal's spectral performance.
Smart Images
Figure CN120582944B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of signal processing technology, and more specifically, to a method and apparatus for peak factor reduction based on peak type. Background Technology
[0002] In-phase or quadrature signals often have a high peak-to-average power ratio. In order to optimize transmitter performance, peak factor reduction technology is usually used to reduce the peak-to-average power ratio of the signal.
[0003] Existing peak factor reduction methods based on peak cancellation require multiple iterations of the following process: calculating signal magnitude, peak detection, pulse generation, and pulse cancellation.
[0004] However, this method requires at least two iterations, which consumes a lot of computation. Summary of the Invention
[0005] This application is provided to address the aforementioned problems existing in the prior art. A peak factor reduction method and apparatus based on peak type according to an embodiment of this application can avoid performing multiple iterative calculations and reduce computational load.
[0006] In a first aspect, embodiments of this application provide a peak factor reduction method based on peak type, including:
[0007] The magnitude of the in-phase orthogonal signal is calculated based on the in-phase and quadrature components of the in-phase orthogonal signal.
[0008] The peak value is determined based on the magnitude of the in-phase orthogonal signal and the preset first peak clipping threshold;
[0009] Based on the peak value and the first peak clipping threshold, determine the type of the peak value;
[0010] Based on the type of the peak, a base pulse is determined; wherein, different peak types correspond to different base pulses, and the base pulse is determined by a filter coefficient design method, with different base pulses corresponding to different filter coefficients.
[0011] The pulse coefficient is calculated based on the first peak clipping threshold, the in-phase quadrature signal, and the magnitude of the in-phase quadrature signal;
[0012] Calculate the peak-shaving pulse based on the base pulse and the pulse coefficient;
[0013] Subtract the peak-clipping pulse from the in-phase quadrature signal to obtain the signal after peak cancellation;
[0014] Determine the magnitude of the signal after peak cancellation;
[0015] Based on the peak cancellation signal, the magnitude of the peak cancellation signal, and the preset second peak clipping threshold, the hard-clipped signal is determined.
[0016] Secondly, embodiments of this application provide a peak factor reduction device based on peak cancellation, comprising:
[0017] The peak value determination module is configured to calculate the magnitude of the in-phase orthogonal signal based on the in-phase and quadrature components of the in-phase orthogonal signal; and determine the peak value based on the magnitude of the in-phase orthogonal signal and a preset first peak clipping threshold.
[0018] The peak cancellation module is configured to: determine the type of the peak value based on the peak value and the first peak clipping threshold; determine the base pulse based on the type of the peak value; wherein different peak value types correspond to different base pulses, the base pulses are determined by a filter coefficient design method, and different base pulses correspond to different filter coefficients; calculate pulse coefficients based on the first peak clipping threshold, the in-phase quadrature signal, and the magnitude of the in-phase quadrature signal; calculate the peak clipping pulse based on the base pulse and the pulse coefficients; and subtract the peak clipping pulse from the in-phase quadrature signal to obtain the peak-cancelled signal.
[0019] The hard peak clipping module is configured to determine the magnitude of the signal after peak cancellation; and to determine the signal after hard peak clipping based on the signal after peak cancellation, the magnitude of the signal after peak cancellation, and a preset second peak clipping threshold.
[0020] Thirdly, embodiments of this application provide a computer program product, including a computer program / instructions, which, when executed by a processor, implement the method described in any of the above embodiments.
[0021] The beneficial effects of the embodiments of this application are as follows: different filter coefficients can determine the basic pulses of different waveforms; based on the type of peak value, a basic pulse that is more suitable for in-phase or quadrature signals can be selected from different basic pulses; the peak clipping pulse obtained from this basic pulse has a better single-shot peak clipping effect, eliminating the need for multiple iterations, reducing computational load, and minimizing system delay caused by multiple iterations. Furthermore, combining peak cancellation with hard peak clipping can further improve the peak clipping effect. Attached Figure Description
[0022] In drawings that are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with or without letter suffixes may indicate different instances of similar parts. The drawings illustrate various embodiments generally by way of example rather than limitation, and are used, together with the description and claims, to explain the disclosed embodiments. Where appropriate, the same reference numerals are used in all drawings to refer to the same or similar parts. Such embodiments are illustrative and not intended to be exhaustive or exclusive embodiments of the apparatus or method.
[0023] Figure 1 This is a flowchart of a peak factor reduction method based on peak type provided in one embodiment of this application;
[0024] Figure 2 This is a schematic diagram of the envelope waveform of different types of peaks provided in one embodiment of this application;
[0025] Figure 3 This is a schematic diagram of a basic pulse for different types of peaks provided in one embodiment of this application;
[0026] Figure 4 This is a schematic diagram of the signal envelope waveform before and after peak clipping, provided in one embodiment of this application;
[0027] Figure 5 This is a schematic diagram illustrating the comparison of power spectral densities of different signals, provided in one embodiment of this application.
[0028] Figure 6 This is a complementary cumulative distribution function curve provided in one embodiment of this application;
[0029] Figure 7 This is a schematic diagram of a launching system provided in one embodiment of this application;
[0030] Figure 8 This is a schematic diagram of a peak factor reduction device based on peak cancellation provided in one embodiment of this application. Detailed Implementation
[0031] To enable those skilled in the art to better understand the technical solutions of this application, the application will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific examples, but this is not intended to limit the application. The terms "first," "second," and "third" used in this application are merely intended to distinguish the corresponding features and do not imply a necessary order, nor do they necessarily represent only the singular form.
[0032] like Figure 1As shown in the figure, this application provides a peak factor reduction method based on peak type, including:
[0033] Step 101: Calculate the magnitude of the in-phase quadrature signal based on the in-phase and quadrature components of the in-phase quadrature signal.
[0034] The magnitude of the in-phase quadrature signal can be calculated using formula (1).
[0035]
[0036] Where a(n) represents the magnitude of the in-phase quadrature signal before peak clipping, i(n) represents the in-phase component, and q(n) represents the quadrature component. The in-phase quadrature signal can be obtained by orthogonal frequency division multiplexing modulation or by other modulation methods.
[0037] Step 102: Determine the peak value based on the magnitude of the in-phase quadrature signal and the preset first peak clipping threshold.
[0038] a(n)>T1 (2)
[0039] a(n)≥a(n-1),a(n)≥a(n+1) (3)
[0040] Wherein, when the magnitude of the nth point of the in-phase orthogonal signal satisfies equations (2) and (3), the magnitude of the nth point of the in-phase orthogonal signal is the peak value, T1 is used to characterize the first peak clipping threshold, a(n-1) is used to characterize the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak value, and a(n+1) is used to characterize the magnitude of the following signal point adjacent to the signal point corresponding to the peak value. For ease of description, the magnitude of the nth point of the in-phase orthogonal signal will be used as an example for the following explanation.
[0041] Step 103: Determine the type of peak value based on the peak value and the first peak clipping threshold.
[0042] In practical applications, the number of types and the criteria for classification are not fixed and can be adjusted according to business needs.
[0043] Step 104: Determine the base pulse based on the type of peak; different peak types correspond to different base pulses, and the base pulses are determined by the filter coefficient design method, with different base pulses corresponding to different filter coefficients.
[0044] The type of peak corresponds one-to-one with the basic pulse. Different filter coefficients can be obtained by setting the filter parameters. The filter coefficients are also called filter pulse impulse responses. The filter coefficients are the basic pulses, and these basic pulses correspond to different peak types.
[0045] Step 105: Calculate the pulse coefficient based on the first peak clipping threshold, the magnitude of the in-phase quadrature signal, and the magnitude of the in-phase quadrature signal.
[0046] The pulse coefficient is adjusted based on the first peak clipping threshold and other basic pulses to obtain the peak clipping pulse. The waveforms of in-phase orthogonal signals are taken into account, so that the peak clipping pulse has a better peak clipping effect.
[0047] Step 106: Calculate the clipping pulse based on the base pulse and pulse coefficient.
[0048] The clipped pulse is the product of the base pulse and the pulse coefficient.
[0049] Step 107: Subtract the clipping pulse from the in-phase quadrature signal to obtain the signal after peak cancellation.
[0050] Step 108: Determine the magnitude of the signal after peak cancellation.
[0051] After peak cancellation, hard clipping is used to further process the signal after peak cancellation in order to improve the peak clipping effect.
[0052] Step 109: Determine the hard-clipped signal based on the peak cancellation signal, the magnitude of the peak cancellation signal, and the preset second peak clipping threshold.
[0053] In this embodiment, different filter coefficients can be used to determine the base pulses for different waveforms. Based on the type of peak value, a base pulse that is more compatible with the in-phase or quadrature signal can be selected from among the different base pulses. The peak-clipping pulse obtained from this base pulse has a better single-shot peak-clipping effect, eliminating the need for multiple iterations, thus reducing computational load and system latency caused by multiple iterations. Furthermore, combining peak cancellation with hard peak clipping can further improve the peak-clipping effect.
[0054] In one embodiment of this application, determining the type of peak value based on the peak value and a first peak clipping threshold includes:
[0055] Calculate the type decision threshold based on the peak value and the first peak reduction threshold;
[0056] The type of the peak is determined based on the signal points adjacent to the signal point corresponding to the peak and the type decision threshold;
[0057] Among them, when the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, and the magnitude of the following signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, the type of the peak is spike;
[0058] When the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak is not less than the type decision threshold, and the magnitude of the following signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, the type of the peak is a forward plateau.
[0059] When the modulus value of the previous signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold and the modulus value of the subsequent signal point adjacent to the signal point corresponding to the peak is not less than the type decision threshold, the type of the peak is the backward platform;
[0060] When the modulus value of the previous signal point adjacent to the signal point corresponding to the peak is not less than the type decision threshold and the modulus value of the subsequent signal point adjacent to the signal point corresponding to the peak is not less than the type decision threshold, the type of the peak is the wide platform.
[0061] Based on Equation (4), calculate the type decision threshold.
[0062] T p (n) = b × T1 + (1 - b) × a(n) (4)
[0063] Where, T p (n) is used to represent the type decision threshold, b is the adjustment coefficient, 0 < b < 1, b is set according to actual requirements. The smaller the value of b, the better the error vector magnitude after peak clipping, but there are more residual peaks; the larger the value of b, the smaller the possibility of residual peaks after peak clipping, but the error vector magnitude is worse.
[0064] Taking the 4 types of peaks as the types, the type division of the peaks is described. The specific division basis is shown in Table 1.
[0065] Table 1 Peak Types and Their Discrimination Conditions
[0066] serial number type Judgment conditions 1 spikes <![CDATA[a(n-1)<T p (n)&a(n+1)<T p (n)]]> 2 Forward Platform <![CDATA[a(n-1)≥T p (n)&a(n+1)<T p (n)]]> 3 Backward Platform <![CDATA[a(n-1)<T p (n)&a(n+1)≥T p (n)]]> 4 Wide platform <![CDATA[a(n-1)≥T p (n)&a(n+1)≥T p (n)]]>
[0067] Schematic diagrams of the envelope waveforms of the 4 types of peaks (Type1-Type 4) are as Figure 2 shown. Where, envelope is used to represent the signal envelope, peak is used to represent the peak, and threshold is used to represent the first peak clipping threshold.
[0068] In the embodiment of the present application, the peaks are classified according to the characteristics of the signal points adjacent to the signal point corresponding to the peak. This classification method considers the characteristics of the waveform near the peak and can improve the peak clipping effect of subsequent peak cancellation.
[0069] In actual application scenarios, other classification methods can also be used. For example, if a(n - 1) < T p (n) & a(n + 1) < T p (n), it belongs to the first category, and others belong to the second category.
[0070] In an embodiment of the present application, based on the first peak clipping threshold, the in-phase quadrature signal, and the modulus value of the in-phase quadrature signal, calculate the pulse coefficient, including:
[0071] The pulse coefficient is determined as: the difference between the magnitude of the in-phase quadrature signal and the first peak clipping threshold, multiplied by the quotient of the magnitudes of the in-phase quadrature signal and the in-phase quadrature signal.
[0072]
[0073] The pulse coefficients are calculated using equation (5), where x(n) is used to characterize in-phase quadrature signals and c(n) is used to characterize the pulse coefficients.
[0074] In one embodiment of this application, determining the hard-clipped signal based on the peak-cancelled signal, the magnitude of the peak-cancelled signal, and a preset second peak-clipping threshold includes:
[0075] When the magnitude of the signal after peak cancellation is not greater than the second peak clipping threshold, the signal after hard peak clipping is determined to be the signal after peak cancellation.
[0076] When the magnitude of the signal after peak cancellation is greater than the second peak clipping threshold, the signal after hard peak clipping is determined as: the second peak clipping threshold multiplied by the quotient of the magnitude of the signal after peak cancellation and the signal after peak cancellation.
[0077] After one pulse clipping, most of the peak values have been removed; however, due to issues such as peak omission and peak regeneration, a small number of peak values may still remain. Therefore, this application embodiment performs another hard clipping to ensure effective peak clipping and peak-to-average power ratio.
[0078] Specifically, equation (6) can be used to perform hard peak clipping.
[0079]
[0080] in, T1 is used to characterize the magnitude of the signal after peak cancellation, and T2 is used to characterize the second peak clipping threshold. Used to characterize the signal after peak cancellation Used to characterize the signal after hard clipping.
[0081] The embodiments of this application perform hard peak clipping based on the relationship between the magnitude of the signal after peak cancellation and the second peak clipping threshold, which can further improve the peak clipping effect.
[0082] The following explanation uses four peak values as examples to illustrate the generation of the basic pulse.
[0083] The first type is characterized by spikes.
[0084] In one embodiment of this application, when the peak type is a spike, the filter is a 2M+1 order finite-length unit impulse response (FIR) low-pass filter, the coefficients of the FIR low-pass filter are the fundamental pulse; the passband edge of the FIR low-pass filter is not less than the effective bandwidth of the in-phase quadrature signal, the passband ripple is less than a preset first threshold, and the stopband attenuation is greater than a preset second threshold, the first threshold and the second threshold are determined by the order of the FIR low-pass filter.
[0085] The underlying pulse corresponding to this type of peak has good frequency domain characteristics and an effective bandwidth similar to that of the signal, thereby reducing the out-of-band components of the signal after peak clipping. It has flat in-band characteristics and meets the characteristics of an FIR low-pass filter.
[0086] The passband ripple is typically less than 6dB, meaning the first threshold is 6dB. Within a reasonable range, the smaller the ripple, the better, to minimize distortion of the passband signal. However, with a fixed filter order, setting the passband ripple too small may degrade transition band performance. This reasonable range is determined by the filter order; a higher filter order allows for a wider range of tolerable passband ripple and stopband attenuation values. Therefore, filter design requires a comprehensive consideration of all three factors based on the actual system requirements.
[0087] The stopband attenuation should be less than the out-of-band transmit template requirement specified in the communication protocol, at least 25dB lower than the protocol requirement. For example, 802.11n requires the out-of-band spurious emissions of the HT_MF signal to be less than -45dB. Considering a certain margin, the stopband attenuation needs to be set to at least 70dB, i.e., the second threshold is 70dB. Within its reasonable range, a larger stopband attenuation value is better, as this reduces the impact of the pulse on out-of-band components; however, with a fixed order, an excessively large stopband attenuation may degrade the in-band error vector amplitude performance.
[0088] The second type is the forward plateau.
[0089] In one embodiment of this application, when the peak type is a forward plateau, the filter is a 2M+1 order FIR low-pass filter; a zero-value tap is added to the end of the original even-symmetric coefficient sequence of the 2M order FIR low-pass filter to generate the coefficient sequence of the 2M+1 order FIR low-pass filter, and the coefficient sequence is the basic pulse; the passband edge of the 2M order FIR low-pass filter is not less than the effective bandwidth of the signal, the passband ripple is less than a preset first threshold, and the stopband attenuation is greater than a preset second threshold, wherein the first threshold and the second threshold are determined by the order of the FIR low-pass filter.
[0090] Based on the requirements for passband edge, passband ripple, and stopband attenuation in the first category, a 2M even-order FIR low-pass filter is designed. Finally, a zero value is added to its tail to form a 2M+1 order filter. The pulse intensity at the point before the center of the basic pulse is consistent with that at the center position.
[0091] The third type is a backward platform.
[0092] In one embodiment of this application, when the peak type is a backward plateau, the filter is a 2M+1 order FIR low-pass filter; a zero-value tap is added to the head of the original even-symmetric coefficient sequence of the 2M order FIR low-pass filter to generate the coefficient sequence of the 2M+1 order FIR low-pass filter, and the coefficient sequence is the basic pulse; the passband edge of the 2M order FIR low-pass filter is not less than the effective bandwidth of the signal, the passband ripple is less than a preset first threshold, and the stopband attenuation is greater than a preset second threshold, wherein the first threshold and the second threshold are determined by the order of the FIR low-pass filter.
[0093] Based on the requirements for passband edge, passband ripple, and stopband attenuation in the first category, a 2M even-order FIR low-pass filter is designed. Finally, a zero value is added to its head to form a 2M+1 order filter. The pulse intensity at the point after the center of the basic pulse is consistent with that at the center position.
[0094] The fourth type is a wide platform for peak values.
[0095] In one embodiment of this application, when the peak type is a wide plateau, the filter is a 2M+1 order FIR low-pass filter, the coefficients of the FIR low-pass filter are the basic pulse; the passband ripple is less than a preset first threshold, the stopband attenuation is greater than a preset second threshold, and the first and second thresholds are determined by the order of the FIR low-pass filter.
[0096] Among them, the passband frequency can be less than the signal bandwidth; the passband ripple requirement is the same as the first type, and the stopband attenuation still needs to be less than the protocol requirement, but there is no need to consider such a large margin, for example, it can be 10dB lower than the protocol requirement.
[0097] The passband edge of Class 4 is smaller than that of Class 1, Class 2 and Class 3, and the stopband attenuation of Class 4 is smaller than that of Class 1, Class 2 and Class 3.
[0098] Taking a basic pulse of length L=13 as an example, the basic pulses corresponding to the four peak types are as follows: Figure 3 As shown in the figure. The horizontal axis 0 represents the pulse center position, corresponding to the detected peak position. h1(n)-h4(n) represent different fundamental pulses.
[0099] The length of the base pulse is an odd number. The longer the pulse, the better the out-of-band spectral performance, the worse the in-band error vector amplitude, and the greater the system delay; conversely, the same applies. The appropriate pulse length needs to be set according to the actual system requirements.
[0100] In any of the above embodiments, the peak clipping effect is enhanced by configuring pulses that match different types of peaks. Combined with hard clipping, the peak-to-average power ratio is strictly guaranteed, avoiding multiple iterations of pulse clipping. Since the base pulse has good spectral characteristics, and the peak amplitude after a single pulse clipping is already very small, the impact of the final hard clipping is negligible. Therefore, any of the above embodiments can ensure that the final signal has good spectral characteristics and control out-of-band spurious components in the frequency domain after peak clipping.
[0101] like Figure 4 The diagram shows the signal envelope waveforms before and after peak clipping. "Original" represents in-phase orthogonal signals, "Peak-related PC-CFR" represents the hard-clipped signal obtained using the method provided in this application (without iterative processing), and "Traditional PC-CFR" represents the clipped signal obtained using an existing peak cancellation-based peak factor reduction method (without iterative processing). The comparison shows that the solution provided in this application has fewer residual peaks and lower intensity compared to existing solutions.
[0102] like Figure 5 The figure shows a comparison of the power spectral density of different signals. The horizontal axis represents frequency, and the vertical axis represents power spectral density. Peak-related+Hard is used to characterize the power spectral density obtained using the scheme provided in this application. Traditional+Hard is used to characterize the power spectral density obtained using existing schemes, which have stronger out-of-band spurious components compared to the scheme provided in this application. Hard Clipping is used to characterize the power spectral density obtained by directly performing hard clipping without peak cancellation, which has severe out-of-band spurious phenomena. Mask is used to characterize the signal transmission spectrum mask specified by the protocol. Figure 5 It is evident that the solution provided in this application has better spectral performance.
[0103] like Figure 6The figure shows the complementary cumulative distribution function curves. The horizontal axis represents the peak-to-average power ratio (PAPR), and the vertical axis represents the probability that the PAPR is greater than the value on the horizontal axis. "Original" corresponds to the in-phase orthogonal signal before peak clipping; "Peak-related" corresponds to the signal after peak cancellation in this application (i.e., without hard peak clipping); "Traditional" corresponds to the signal obtained using the existing scheme; and "Peak-related+Hard" corresponds to the signal after hard peak clipping obtained using the scheme in this application. A comparison reveals that the scheme provided in this application has a smaller PAPR.
[0104] like Figure 7 As shown, the method provided in this application is used for the peak clipping module of a transmission system, including single pulse peak clipping, i.e., steps 101-107, and also includes hard peak clipping, i.e., steps 108 and 109.
[0105] like Figure 8 As shown, this application provides a peak factor reduction device based on peak cancellation, comprising:
[0106] The peak value determination module 801 is configured to calculate the magnitude of the in-phase orthogonal signal based on the in-phase and quadrature components of the in-phase orthogonal signal; and determine the peak value based on the magnitude of the in-phase orthogonal signal and a preset first peak clipping threshold.
[0107] The peak cancellation module 802 is configured to determine the type of peak based on the peak value and a first peak clipping threshold; determine the base pulse based on the peak value type; wherein different peak values correspond to different base pulses, the base pulses are determined by a filter coefficient design method, and different base pulses correspond to different filter coefficients; calculate the pulse coefficient based on the first peak clipping threshold, the in-phase quadrature signal, and the magnitude of the in-phase quadrature signal; calculate the peak clipping pulse based on the base pulse and the pulse coefficient; and subtract the peak clipping pulse from the in-phase quadrature signal to obtain the peak-cancelled signal.
[0108] The hard peak clipping module 803 is configured to determine the magnitude of the signal after peak cancellation; based on the signal after peak cancellation, the magnitude of the signal after peak cancellation, and a preset second peak clipping threshold, the hard peak clipping signal is determined.
[0109] In one embodiment of this application, the peak cancellation module 802 is configured to calculate a type decision threshold based on the peak value and a first peak clipping threshold; and determine the type of the peak value based on the signal points adjacent to the signal point corresponding to the peak value and the type decision threshold.
[0110] Among them, when the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, and the magnitude of the following signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, the type of the peak is spike;
[0111] When the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak is not less than the type decision threshold, and the magnitude of the following signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, the type of the peak is a forward plateau.
[0112] When the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, and the magnitude of the following signal point adjacent to the signal point corresponding to the peak is not less than the type decision threshold, the type of the peak is backward plateau.
[0113] The peak value is a wide plateau if the magnitude of the preceding signal point adjacent to the peak value is not less than the type decision threshold and the magnitude of the following signal point adjacent to the peak value is not less than the type decision threshold.
[0114] In one embodiment of this application, the peak cancellation module 802 is configured to determine the pulse coefficient as: the difference between the magnitude of the in-phase quadrature signal and the first peak clipping threshold, multiplied by the quotient of the magnitudes of the in-phase quadrature signal and the in-phase quadrature signal.
[0115] In one embodiment of this application, the hard-clipping module 803 is configured to determine the hard-clipped signal as the peak cancellation signal when the magnitude of the peak cancellation signal is not greater than the second peak clipping threshold; and to determine the hard-clipped signal as: the second peak clipping threshold multiplied by the quotient of the peak cancellation signal and the magnitude of the peak cancellation signal when the magnitude of the peak cancellation signal is greater than the second peak clipping threshold.
[0116] This application provides a computer program product, including a computer program / instructions, which, when executed by a processor, implement the method as described in any of the above embodiments.
[0117] Furthermore, although exemplary embodiments have been described herein, their scope includes any and all embodiments based on this application that have equivalent elements, modifications, omissions, combinations (e.g., schemes where various embodiments overlap), adaptations, or changes. While several embodiments of wireless communication methods and wireless communication components have been described separately, it should be understood that the method details described in the wireless communication component description can also be incorporated into various embodiments of the wireless communication method, and vice versa.
[0118] The elements in the claims will be interpreted broadly based on the language used in the claims and are not limited to the examples described in this specification or during the implementation of this application, the examples of which will be interpreted as non-exclusive. Therefore, this specification and examples are intended to be considered merely illustrative, and the true scope and spirit are indicated by the claims and the full scope of their equivalents.
[0119] The order of the steps in this application is merely exemplary and not restrictive. The execution order of the steps can be adjusted without affecting the implementation of this application (without disrupting the logical relationship between the required steps), and the various embodiments obtained after the adjustment still fall within the scope of this application.
[0120] The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more of them) can be used in combination with each other. Other embodiments may be used by those skilled in the art upon reading the above description. Furthermore, in the above detailed description, various features may be grouped together to simplify the application. This should not be construed as an intention that a disclosed feature not claimed is necessary for any claim. Rather, the subject matter of the invention may be less than all the features of a particular disclosed embodiment. Thus, the claims are incorporated herein by reference as examples or embodiments, wherein each claim is an independent, separate embodiment, and these embodiments are contemplated to be combined with each other in various combinations or arrangements. The scope of the invention should be determined by reference to the appended claims and the full scope of their equivalents.
Claims
1. A crest factor reduction method based on peak type, characterized by, include: The magnitude of the in-phase orthogonal signal is calculated based on the in-phase and quadrature components of the in-phase orthogonal signal. The peak value is determined based on the magnitude of the in-phase orthogonal signal and the preset first peak clipping threshold; Based on the peak value and the first peak clipping threshold, determine the type of the peak value; Based on the type of the peak, a base pulse is determined; wherein, different peak types correspond to different base pulses, and the base pulse is determined by a filter coefficient design method, with different base pulses corresponding to different filter coefficients. The pulse coefficient is calculated based on the first peak clipping threshold, the in-phase quadrature signal, and the magnitude of the in-phase quadrature signal; Calculate the peak-shaving pulse based on the base pulse and the pulse coefficient; Subtract the peak-clipping pulse from the in-phase quadrature signal to obtain the signal after peak cancellation; Determine the magnitude of the signal after peak cancellation; Based on the peak cancellation signal, the magnitude of the peak cancellation signal, and the preset second peak clipping threshold, the hard-clipped signal is determined.
2. The method as described in claim 1, characterized in that, Based on the peak value and the first peak clipping threshold, the type of the peak value is determined, including: Based on the peak value and the first peak reduction threshold, calculate the type decision threshold; The type of the peak value is determined based on the signal points adjacent to the signal point corresponding to the peak value and the type decision threshold. Wherein, when the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, and the magnitude of the following signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, the type of the peak is spike; When the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak is not less than the type decision threshold, and the magnitude of the following signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, the type of the peak is a forward platform; When the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak is less than the type decision threshold, and the magnitude of the following signal point adjacent to the signal point corresponding to the peak is not less than the type decision threshold, the type of the peak is a backward platform. The peak value is a wide plateau if the magnitude of the preceding signal point adjacent to the signal point corresponding to the peak value is not less than the type decision threshold and the magnitude of the following signal point adjacent to the signal point corresponding to the peak value is not less than the type decision threshold.
3. The method as described in claim 1, characterized in that, Based on the first peak clipping threshold, the in-phase quadrature signal, and the magnitude of the in-phase quadrature signal, the pulse coefficient is calculated, including: The pulse coefficient is determined as: the difference between the magnitude of the in-phase quadrature signal and the first peak clipping threshold, multiplied by the quotient of the magnitude of the in-phase quadrature signal and the magnitude of the in-phase quadrature signal.
4. The method as described in claim 1, characterized in that, Based on the peak cancellation signal, the magnitude of the peak cancellation signal, and a preset second peak clipping threshold, the hard-clipped signal is determined, including: When the magnitude of the peak cancellation signal is not greater than the second peak clipping threshold, the hard-clipped signal is determined to be the peak cancellation signal. When the magnitude of the peak cancellation signal is greater than the second peak clipping threshold, the hard-clipped signal is determined to be: the second peak clipping threshold multiplied by the quotient of the peak cancellation signal and the magnitude of the peak cancellation signal.
5. The method as described in claim 2, characterized in that, wherein, When the peak type is a spike, the filter is a 2M+1 order finite-length unit impulse response (FIR) low-pass filter, and the coefficients of the FIR low-pass filter are the fundamental pulse; the passband edge of the FIR low-pass filter is not less than the effective bandwidth of the in-phase quadrature signal, the passband ripple is less than a preset first threshold, and the stopband attenuation is greater than a preset second threshold, wherein the first threshold and the second threshold are determined by the order of the FIR low-pass filter.
6. The method as described in claim 2, characterized in that, wherein When the peak type is a forward plateau, the filter is a 2M+1 order FIR low-pass filter; a zero-value tap is added to the end of the original even-symmetric coefficient sequence of the 2M order FIR low-pass filter to generate the coefficient sequence of the 2M+1 order FIR low-pass filter, and the coefficient sequence is the basic pulse; the passband edge of the 2M order FIR low-pass filter is not less than the effective bandwidth of the signal, the passband ripple is less than a preset first threshold, and the stopband attenuation is greater than a preset second threshold, the first threshold and the second threshold are determined by the order of the FIR low-pass filter.
7. The method as described in claim 2, characterized in that, wherein, When the peak type is a backward plateau, the filter is a 2M+1 order FIR low-pass filter; a zero-value tap is added to the head of the original even-symmetric coefficient sequence of the 2M order FIR low-pass filter to generate the coefficient sequence of the 2M+1 order FIR low-pass filter, and the coefficient sequence is the basic pulse; the passband edge of the 2M order FIR low-pass filter is not less than the effective bandwidth of the signal, the passband ripple is less than a preset first threshold, and the stopband attenuation is greater than a preset second threshold, the first threshold and the second threshold are determined by the order of the FIR low-pass filter.
8. The method as described in claim 2, characterized in that, wherein, When the peak type is a wide plateau, the filter is a 2M+1 order FIR low-pass filter, and the coefficients of the FIR low-pass filter are the fundamental pulse; the passband ripple is less than a preset first threshold, and the stopband attenuation is greater than a preset second threshold, the first threshold and the second threshold are determined by the order of the FIR low-pass filter.
9. A crest factor reduction apparatus based on peak cancellation, characterized by, include: The peak value determination module is configured to calculate the magnitude of the in-phase orthogonal signal based on the in-phase and quadrature components of the in-phase orthogonal signal. The peak value is determined based on the magnitude of the in-phase orthogonal signal and the preset first peak clipping threshold; The peak cancellation module is configured to determine the type of the peak based on the peak value and the first peak reduction threshold; Based on the type of the peak, a base pulse is determined; wherein, different peak types correspond to different base pulses, and the base pulse is determined by a filter coefficient design method, with different base pulses corresponding to different filter coefficients; based on the first peak clipping threshold, the in-phase quadrature signal, and the magnitude of the in-phase quadrature signal, pulse coefficients are calculated; based on the base pulse and the pulse coefficients, a peak clipping pulse is calculated; the peak clipping pulse is subtracted from the in-phase quadrature signal to obtain the peak-cancelled signal; The hard peak clipping module is configured to determine the magnitude of the signal after peak cancellation; and to determine the signal after hard peak clipping based on the signal after peak cancellation, the magnitude of the signal after peak cancellation, and a preset second peak clipping threshold.
10. A computer program product comprising computer programs / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the method as described in any one of claims 1 to 8.