WO2016165481A1

WO2016165481A1 - Digital signal processing method and device

Info

Publication number: WO2016165481A1
Application number: PCT/CN2016/074244
Authority: WO
Inventors: 孙青岩; 舒峰; 邓英; 童煊
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-08-27
Filing date: 2016-02-22
Publication date: 2016-10-20
Also published as: CN105245480B; CN105245480A

Abstract

Provided are a digital signal processing method and device. The method comprises: conducting interpolation on a first digital signal with N points, to obtain a second digital signal, wherein each point of the first digital signal is interpolated into M points, where both N and M are greater than or equal to 2, and the phase difference between two adjacent points of the M points is Q; dividing N*M points of the second digital signal into N groups in sequence, wherein the N points of the first digital signal are located in positions except for the two end points in corresponding groups; selecting a point with the maximum amplitude from each group of the N groups, to obtain a third digital signal, wherein the phase difference between each point of the third digital signal and a corresponding point of the N points is less than (M-1)*Q; and according to the third digital signal, conducting peak clipping processing on the first digital signal, thereby solving the problem in the related art that the phase error between an offset pulse and a main signal is large when peak clipping is conducted.

Description

Digital signal processing method and device

Technical field

The present invention relates to the field of communications, and in particular to a digital signal processing method and apparatus.

Background technique

The mobile communication base station transmitter gradually transitions from the original single-band single-mode single-carrier to the multi-band multi-standard multi-carrier, especially with the 4th Generation mobile communication technology (4G) long-term evolution (Long -Term Evolution (LTE) is a large-scale commercial application. The configuration bandwidth of the signal is up to several hundred MHz. This multi-carrier large bandwidth configuration has a high Peak to Average Power Ratio (PAPR). If the peak power is too large, it will easily exceed the saturation point of the amplifier, resulting in severe signal compression, which affects the Adjacent Channel Leakage power Ratio (ACLR). In order to reduce this nonlinear distortion, it is usually necessary to ensure that the peak value of the signal cannot exceed the saturation compression point of the power amplifier. This requires that the average power of the signal should be retracted according to the peak-to-average ratio, resulting in a decrease in the efficiency of the power amplifier and a reduction in power back-off. The coverage of the base station, so in order to reduce the average power back-off, the PAPR of the signal is reduced in the digital domain, and clipping is a technique for reducing the signal PAPR in the digital domain.

At present, the peak clipping technology adopted by the industry is mainly a peak pulse shaping cancellation algorithm, which is based on the error vector magnitude (Error Vector Magnitude, referred to as EVM) in exchange for low PAPR. The peak pulse shaping cancellation algorithm mainly includes two modules of peak search and shaping filter calculation, wherein the peak search method determines the final peak clipping performance. The peak search currently used in the industry for wideband signals is usually the traditional interpolation filtering plus peak extraction method. Although this method can find large peaks, the interpolation pulse and peak extraction result in a larger phase error between the cancellation pulse and the main signal, and The higher the interpolation factor, the larger the phase error, which affects PAPR and EVM after peak clipping.

In view of the problem that the phase error between the canceling pulse and the main signal is large when the peak clipping is performed in the related art, an effective solution has not been proposed yet.

Summary of the invention

The present invention provides a digital signal processing method and apparatus for solving at least the problem of large phase error between the cancellation pulse and the main signal when peak clipping is performed in the related art.

According to an aspect of the present invention, a digital signal processing method is provided, comprising: interpolating a first digital signal having N points to obtain a second digital signal, wherein each point in the first digital signal Interpolated into M points, wherein N and M are both greater than or equal to 2, the phase difference between two adjacent points of the M points is Q; N*M in the second digital signal is sequentially arranged The points are divided into N packets, wherein the N points in the first digital signal are located at positions other than the two endpoints in the corresponding packet; from each of the N packets Selecting a point having the largest amplitude to obtain a third digital signal, wherein each point in the third digital signal and a corresponding point among the N points The phase difference between them is less than (M-1)*Q; the first digital signal is subjected to peak clipping processing according to the third digital signal.

Optionally, performing peak clipping processing on the first digital signal according to the third digital signal includes: searching, from the third digital signal, a point whose amplitude is greater than or equal to a first threshold and less than the first threshold Pointing; setting a magnitude of a point smaller than the first threshold to 0, and decreasing a magnitude of the point greater than or equal to the first threshold by the first threshold to obtain a fourth digital signal; using the The four digital signals perform peak clipping processing on the first digital signal, wherein the peak clipping processing is for reducing a magnitude of a point of the first digital signal corresponding to the point equal to or greater than the first threshold.

Optionally, performing peak clipping processing on the first digital signal by using the fourth digital signal includes: subtracting the fourth digital signal from the first digital signal to obtain a fifth digital signal after peak clipping; Alternatively, filtering the fourth digital signal to obtain a sixth digital signal, and subtracting the sixth digital signal from the first digital signal to obtain a peaked seventh digital signal.

Optionally, the first digital signal having N points is interpolated, and obtaining the second digital signal includes: setting an ith point in the first digital signal to a second one of the second digital signals ((i-1)*M+1) points at which (M-1) points generated by interpolating the i-th point in the first digital signal are set at the second digital signal Between the ((i-1)*M+1)th point and the ((i)*M+1)th point, where 1≤i≤N; the second number is sequentially Decomposing N*M points in the signal into N groups includes: setting a first point to a Pth point in the second digital signal as the first one of the N packets, where 2 ≤ P ≤ (M-1); the ((P+1)+(j-2)*M) points in the second digital signal to the ((P+1)+(j-1) *M-1) The points are set to the jth group, where 2 ≤ j ≤ N.

Optionally, said

Optionally, selecting a point with the largest amplitude from each of the N packets, and obtaining the third digital signal includes: acquiring the amplitude and phase of each point in each of the N packets. And obtaining, from each of the packets, a magnitude of a point having the largest amplitude; generating a point in the third digital signal according to the obtained amplitude of the point having the largest amplitude and a corresponding phase.

According to another aspect of the present invention, there is provided a digital signal processing apparatus comprising: an interpolation module configured to interpolate a first digital signal having N points to obtain a second digital signal, wherein the first digital Each point in the signal is interpolated into M points, wherein N and M are both greater than or equal to 2, and the phase difference between two adjacent points of the M points is Q; the dividing module is set to be in order N*M points in the second digital signal are divided into N packets, wherein the N points in the first digital signal are located at positions other than the two endpoints in the corresponding group; a selection module, configured to select a point having the largest amplitude from each of the N packets to obtain a third digital signal, wherein each of the third digital signals and the N points The phase difference between the corresponding points in the middle is less than (M-1)*Q; and the processing module is configured to perform peak clipping processing on the first digital signal according to the third digital signal.

Optionally, the processing module includes: a searching unit, configured to search, from the third digital signal, a point whose amplitude is greater than or equal to a first threshold and a point smaller than the first threshold; and the setting unit is set to be smaller than The amplitude of the point of the first threshold is set to 0, and the amplitude of the point equal to or greater than the first threshold is decreased by the first threshold to obtain a fourth digital signal; and the processing unit is configured to use the The fourth digital signal performs peak clipping processing on the first digital signal, wherein the peak clipping process is for reducing a magnitude of a point of the first digital signal corresponding to the point equal to or greater than the first threshold.

Optionally, the processing unit includes: a processing subunit configured to subtract the fourth digital signal from the first digital signal to obtain a fifth digital signal after peak clipping; or a filtering subunit, set to be The fourth digital signal is filtered to obtain a sixth digital signal, and the sixth digital signal is subtracted from the first digital signal to obtain a seventh digital signal after peak clipping.

Optionally, the interpolation module is configured to interpolate the first digital signal to obtain the second digital signal: setting an ith point in the first digital signal to the second The ((i-1)*M+1)th point in the digital signal, the (M-1) points generated by interpolating the i-th point in the first digital signal are set in the Between the ((i-1)*M+1)th point and the ((i)*M+1)th point in the second digital signal, where 1≤i≤N; the division module is set To divide N*M points in the second digital signal into N packets in order by setting the first point to the Pth point in the second digital signal to the N pieces a first packet in the packet, where 2 ≤ P ≤ (M-1); the ((P+1)+(j-2)*M) points in the second digital signal to the ( (P+1)+(j-1)*M-1) The points are set to the jth group, where 2≤j≤N.

Optionally, said

Optionally, the selecting module includes: a first acquiring unit, configured to acquire a magnitude and a phase of each point in each of the N packets; and a second acquiring unit, configured to And obtaining a magnitude of a point having the largest amplitude; and generating a unit configured to generate a point in the third digital signal according to the acquired amplitude of the point having the largest amplitude and the corresponding phase.

By the present invention, the first digital signal having N points is interpolated to obtain a second digital signal, wherein each point in the first digital signal is interpolated into M points, wherein N and M are both Or greater than or equal to 2, a phase difference between two adjacent points of the M points is Q; N*M points in the second digital signal are sequentially divided into N groups, wherein the The N points in a digital signal are located at positions other than the two endpoints in the corresponding group; a point having the largest amplitude is selected from each of the N packets to obtain a third number a signal, wherein a phase difference between each of the third digital signals and a corresponding one of the N points is less than (M-1)*Q; according to the third digital signal pair A digital signal is used for peak clipping. The problem that the phase error between the canceling pulse and the main signal is large when the peak is cut in the related art is solved, and the effect of reducing the phase error between the canceling pulse and the main signal is achieved.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a flow chart of a digital signal processing method in accordance with an embodiment of the present invention;

2 is a block diagram showing the structure of a digital signal processing apparatus according to an embodiment of the present invention;

3 is a block diagram showing the structure of a processing module 28 in a digital signal processing apparatus according to an embodiment of the present invention;

4 is a block diagram showing the structure of a processing unit 36 in a digital signal processing apparatus according to an embodiment of the present invention;

FIG. 5 is a structural block diagram of a selection module 26 in a digital signal processing apparatus according to an embodiment of the present invention; FIG.

6 is a comparison diagram of a main signal to be peaked and a main signal after peak clipping according to an embodiment of the present invention;

7 is a signal obtained after hard clipping processing according to an embodiment of the present invention;

8 is an offset pulse formed by filtering through a shaping filter according to an embodiment of the present invention;

9 is a schematic diagram showing the position and structure of a digital peak link of a mobile communication transmitter based on a minimum phase error method for peak-finding based on a minimum phase error method;

10 is a structural diagram of a peak search module for peak search based on a minimum phase error method according to an embodiment of the present invention;

11 is a structural diagram of a minimum phase error peak search module for peak search based on a minimum phase error method according to an embodiment of the present invention.

detailed description

The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

It is to be understood that the terms "first", "second" and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a particular order or order.

In order to solve the problem that the phase error between the cancellation pulse and the main signal is large when performing peak clipping in the related art, the key is to reduce the phase error caused by the peak search while achieving the goal of reducing the peak-to-average ratio, in the present invention. In the embodiment, how to reduce the phase error caused by the peak search while achieving the goal of reducing the peak-to-average ratio is proposed, and a digital signal processing method is proposed. The method will be described below.

A digital signal processing method is provided in this embodiment. FIG. 1 is a flowchart of a digital signal processing method according to an embodiment of the present invention. As shown in FIG. 1, the flow includes the following steps:

Step S102, interpolating a first digital signal having N points, to obtain a second digital signal, wherein each point in the first digital signal is interpolated into M points, wherein N and M are greater than or equal to 2 The phase difference between two adjacent points of the M points is Q;

Step S104, dividing N*M points in the second digital signal into N groups in sequence, wherein N points in the first digital signal are located at positions other than the two end points in the corresponding group;

Step S106, selecting a point with the largest amplitude from each of the N packets to obtain a third digital signal, wherein each point in the third digital signal is between the corresponding point of the N points The phase difference is less than (M-1)*Q;

Step S108, performing peak clipping processing on the first digital signal according to the third digital signal.

Through the above steps, when grouping N*M points, the points in the first digital signal are located at the non-end point positions in each group, and the points with the largest amplitude selected in each group are in the corresponding group. Phase error of a point in the first digital signal Less than (M-1)*Q, the solution in the embodiment of the present invention can effectively reduce the third digital signal for the point in the first digital signal in the related art to be located at the starting end position in each group. The phase of the three digital signals coincides with the phase of the cancellation pulse described above and the phase error between the first digital signal (corresponding to the main signal described above), thereby reducing the phase error between the cancellation pulse and the main signal. The invention solves the problem that the phase error between the canceling pulse and the main signal is large when the peak is cut in the related art, thereby achieving the effect of reducing the phase error between the canceling pulse and the main signal (before and after the first digital signal is peaked) The comparison chart can refer to FIG. 6 described later, and it should be noted that FIG. 6 is only an example).

In an optional embodiment, the operation performed in the above step S108 is to perform peak clipping processing on the first digital signal according to the third digital signal, and the processing method may be multiple. The step S108 is exemplified below. : finding, from the third digital signal, a point whose amplitude is greater than or equal to the first threshold and a point smaller than the first threshold; setting a magnitude of a point smaller than the first threshold to 0, and setting a width of a point greater than or equal to the first threshold Decreasing the first threshold to obtain a fourth digital signal; performing peak clipping processing on the first digital signal using the fourth digital signal, wherein the peak clipping process is for reducing a point in the first digital signal that is greater than or equal to the first threshold The amplitude of the corresponding point (the fourth digital signal can be as shown in Fig. 7 to be described later (Fig. 7 is only an example)).

In an optional embodiment, performing peak clipping processing on the first digital signal by using the fourth digital signal includes: subtracting the fourth digital signal from the first digital signal to obtain a fifth digital signal after peak clipping; or Filtering the fourth digital signal to obtain a sixth digital signal, and subtracting the sixth digital signal from the first digital signal to obtain a seventh digital signal after clipping (the sixth digital signal obtained by filtering the fourth digital signal) It can be as shown in FIG. 8 (FIG. 8 is only an example)).

In an optional embodiment, interpolating the first digital signal having N points, and obtaining the second digital signal comprises: setting an ith point in the first digital signal to a number in the second digital signal ( (i-1)*M+1) points, the (M-1) points generated by interpolating the i-th point in the first digital signal are set in the second digital signal ((i- 1) *M+1) between the points and the ((i)*M+1) points, where 1≤i≤N; sequentially dividing the N*M points in the second digital signal into N The grouping includes: setting the first point to the Pth point of the second digital signal to the first one of the N groups, where 2≤P≤(M-1); the second digital signal The ((P+1)+(j-2)*M) points to the ((P+1)+(j-1)*M-1) points are set to the jth group, where 2 ≤j≤N. That is, through the above-mentioned grouping, N points in the first digital signal can be respectively allocated to N groups, and each of the N points in the first digital signal is in the corresponding group. At the endpoint, the phase difference between the point with the largest amplitude selected from each group and the point in the first digital signal in the corresponding group can be reduced by the above interpolation and grouping method.

In an alternative embodiment, the above

among them,

Round down the result for M/2, when P is

In the above group, except for the first group, the points in the first digital signals in the remaining groups are located at the center position of all the points of the group, and the points with the largest amplitude selected from each group can be realized. The minimum phase difference between the points in the first digital signal in the corresponding group.

In an optional embodiment, in the foregoing step S106, it is described that selecting a point with the largest amplitude from each of the N packets to obtain a third digital signal may be implemented in multiple steps. For example, obtaining the amplitude and phase of each point in each of the N packets; obtaining the amplitude of the point having the largest amplitude from each of the packets; and the magnitude of the point according to the largest amplitude obtained The corresponding phase generates a point in the third digital signal.

Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware, but in many cases, the former is A better implementation. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a storage medium (such as ROM/RAM, disk, The optical disc includes a number of instructions for causing a terminal device (which may be a cell phone, a computer, a server, or a network device, etc.) to perform the methods described in various embodiments of the present invention.

In the embodiment, a digital signal processing device is also provided, which is used to implement the above-mentioned embodiments and preferred embodiments, and has not been described again. As used below, the term "module" may implement a combination of software and/or hardware of a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware, is also possible and contemplated.

2 is a block diagram showing the structure of a digital signal processing apparatus according to an embodiment of the present invention. As shown in FIG. 2, the apparatus includes an interpolation module 22, a division module 24, a selection module 26, and a processing module 28. The apparatus will be described below.

The interpolation module 22 is configured to interpolate the first digital signal having N points to obtain a second digital signal, wherein each point in the first digital signal is interpolated into M points, wherein N and M are 2 or more, the phase difference between two adjacent points of the M points is Q; the dividing module 24 is connected to the interpolation module 22, and is arranged to sequentially divide N*M points in the second digital signal into N packets, wherein the N points in the first digital signal are located at positions other than the two endpoints in the corresponding packet; the selection module 26 is connected to the partitioning module 24, and is set to be from the N packets. Selecting a point with the largest amplitude in each group to obtain a third digital signal, wherein a phase difference between each point in the third digital signal and a corresponding point among the N points is less than (M-1) *Q; the processing module 28 is coupled to the selection module 26, and configured to perform peak clipping processing on the first digital signal according to the third digital signal.

FIG. 3 is a structural block diagram of a processing module 28 in a digital signal processing apparatus according to an embodiment of the present invention. As shown in FIG. 3, the processing module 28 includes a searching unit 32, a setting unit 34, and a processing unit 36. 28 for explanation.

The searching unit 32 is configured to search, from the third digital signal, a point whose amplitude is greater than or equal to the first threshold and a point smaller than the first threshold; the setting unit 34 is connected to the searching unit 32, and is set to be smaller than the first threshold. The amplitude of the point is set to 0, and the amplitude of the point greater than or equal to the first threshold is lowered by a first threshold to obtain a fourth digital signal; the processing unit 36 is coupled to the above-described setting unit 34, and configured to use the fourth digital signal And performing peak clipping processing on the first digital signal, wherein the peak clipping processing is for reducing a magnitude of a point in the first digital signal corresponding to a point greater than or equal to the first threshold.

4 is a block diagram showing the structure of a processing unit 36 in a digital signal processing apparatus according to an embodiment of the present invention. As shown in FIG. 4, the processing unit 36 includes a processing subunit 42 or a filtering subunit 44, and the processing unit 36 is performed below. Description.

The processing sub-unit 42 is configured to subtract the fourth digital signal from the first digital signal to obtain a fifth digital signal after clipping, and the filtering sub-unit 44 is configured to filter the fourth digital signal to obtain a sixth digital signal. The sixth digital signal is subtracted from the first digital signal to obtain a seventh digital signal after peak clipping. The processing sub-unit 42 and the filtering sub-unit 44 in FIG. 4 are both drawn with dashed lines, indicating that the processing unit 36 includes the processing sub-unit 42, or the processing unit 36 includes a filtering sub-unit 44.

In an optional embodiment, the interpolation module 22 may interpolate the first digital signal to obtain a second digital signal: the ith point in the first digital signal is set to be in the second digital signal. The first ((i-1)*M+1) points, the (M-1) points generated by interpolating the i-th point in the first digital signal are set in the second digital signal (( I-1)*M+1) between the points and the (i)*M+1) points, wherein 1≤i≤N; the dividing module 24 may sequentially and secondly output the second digital signal in the following manner The N*M points in the middle are divided into N groups: the first point to the Pth point in the second digital signal are set as the first one of the N groups, where 2≤P≤(M- 1); set the ((P+1)+(j-2)*M) points in the second digital signal to the ((P+1)+(j-1)*M-1) point setting For the jth group, where 2 ≤ j ≤ N.

In an alternative embodiment, the above

FIG. 5 is a structural block diagram of a selection module 26 in a digital signal processing apparatus according to an embodiment of the present invention. As shown in FIG. 5, the selection module 26 includes a first acquisition unit 52, a second acquisition unit 54, and a generation unit 56. The selection module 26 will be described.

The first obtaining unit 52 is configured to acquire the amplitude and phase of each point in each of the N packets; the second obtaining unit 54 is connected to the first obtaining unit 52, and is configured to obtain the amplitude from each group The amplitude of the point having the largest value; the generating unit 56, coupled to the second obtaining unit 54 described above, is configured to generate a point in the third digital signal according to the amplitude of the point at which the acquired amplitude is the largest and the corresponding phase.

The above embodiments mainly explain how to interpolate, group, and search for peaks. The following is a description of the overall peak clipping process:

In the embodiment of the present invention, a wideband peak clipping method and apparatus for minimum phase error peak finding of a wideband multicarrier signal is also proposed. The peak value search method with minimum phase error is applied to the wideband multi-carrier signal, and the peak value of the signal is accurately estimated, which realizes high-speed peak-searching, low-rate peak clipping scheme, and not only improves the RF index of the broadband signal. It improves the efficiency of the amplifier output, and also reduces the overhead of logic resources and saves costs. Among them, the peak peak clipping device based on the minimum phase error includes the following modules:

Main signal delay module, digital up-conversion module, signal modulus phase separation module, peak search module for minimum phase error, hard clipping module, peak modulus and phase synthesis module, shaping filter calculation module, peak cancellation module; Explain the various modules:

The main signal delay module mainly performs a certain time delay on the peak cut input signal to ensure that the generated canceling pulse is aligned in time.

The digital up-conversion module performs multi-stage upsampling on the received digital intermediate frequency signal to improve the rate of the signal and improve the accuracy of the peak estimation.

The signal modulus phase separation module performs modulus and phase separation on the up-converted IQ complex signal.

The peak search module with minimum phase error performs a large peak search based on the modulus of the signal and ensures that the phase error of the signal before upsampling is as small as possible.

The hard clipping module subtracts the signal modulus value after the peak search from the preset peak clipping threshold to obtain a signal peak to be cancelled;

The modulo value and phase synthesis module of the peak signal: the peak signal and its corresponding phase synthesize the complex signal.

The shaping filter calculation module generates a shaping filter coefficient that matches the main signal based on the carrier filter coefficient of the main signal, the frequency control word, and the power information.

Peak canceling module: Filtering the peak signal to generate a canceling pulse, and subtracting the delayed main signal from the canceling pulse to achieve peak clipping.

The minimum phase error peak search module further includes: a peak grouping module and a peaking module.

The peak grouping module groups the peak signals after multi-stage upsampling according to the principle of ensuring the minimum phase error of all the peaks and the main signal before the upsampling, and the length of the signals in the group is a multiple of the multi-level interpolation, within each group, According to the peak-to-average ratio after peak clipping, the peak value after interpolation and the position of the main signal before interpolation are used. By such grouping, the phase error of the peak value of all signals and the main signal is optimized, and the cutting is improved to some extent. PAPR and EVM indicators for post-peak signals.

The peak extraction module filters the peak signals in each group, extracts according to the principle of maximum peak value, records the position extracted to the peak, and performs phase extraction according to the position of the peak. The peak signal after the extraction is consistent with the peak signal rate of the peak clipping.

The method for wide-band peak clipping based on minimum phase error peak searching according to an embodiment of the present invention is described below with reference to the accompanying drawings. FIG. 6 is a comparison diagram of a main signal to be peaked and a main signal after peak clipping according to an embodiment of the present invention, wherein The solid line indicates the signal modulus of the peak cut-in; the dotted line indicates the modulus of the signal after peak clipping, and the 1413 sample point is taken as an example in FIG. The method comprises the following steps:

Step 1: Receive the signal of the current link and the configuration information of the signal, and then configure corresponding peak clipping threshold, carrier filter coefficient, frequency control word of the carrier, and the like.

Step 2: multi-level digital up-conversion processing, multi-level interpolation filtering processing on the signal according to the bandwidth of the input signal, and performing peak estimation.

Step 3. Signal modulus and phase separation processing. Calculate the modulus and phase of the current in-phase/Quadrature (referred to as IQ) complex signal.

Step 4, peak packet processing. The modulus values of the signals are grouped by a multiple of the interpolation.

Step 5, peak extraction processing. The peak signal in each group is digitally down-converted and extracted to the same rate as the main signal.

Step 6. Hard peak clipping. That is, the peak signal is subtracted from the preset peak clipping threshold to obtain a peak signal to be cancelled. As shown in FIG. 7, FIG. 7 is a signal obtained after hard clipping processing according to an embodiment of the present invention, and point 1413 in FIG. That is, the modulus value to be cancelled obtained by subtracting the modulo value of the original signal (that is, the main signal when the peak is to be clipped) and the clipping peak threshold.

Step 7. Modulo and phase synthesis IQ complex signal processing. The peak signal is combined with its corresponding phase to form an IQ complex signal.

In step 8, a shaping filter is generated. According to the frequency control word of the signal, carrier filter coefficient, carrier power information calculation The shaping filter coefficient of the outgoing signal.

Step 9. Peak cancellation processing. First, the peak-extracted signal and the generated shaping filter coefficient are filtered to generate a cancellation pulse for peak clipping cancellation with the original signal. Then, the main signal and the canceling pulse are correspondingly subtracted to obtain a final peak-to-peak ratio signal, which is sent to the digital predistortion module, as shown in FIG. 8. FIG. 8 is a shaped filter according to an embodiment of the present invention. The cancellation pulse formed after filtering. After the pulse is cancelled by the delayed signal, the peaked signal shown by the chain line in FIG. 6 is obtained.

FIG. 9 is a schematic diagram showing the position and structure of a wideband peak clipping based on a minimum phase error method in a mobile communication transmitter digital link module according to an embodiment of the present invention. As shown in FIG. 9, the device is located in a transmitter according to an embodiment of the present invention. After the digital up-conversion (DUC) module of the digital link, the digital pre-distortion (DPD) module mainly includes the main signal delay module (ie, in FIG. 9). The time delay module), the peak search module and the online computational shaping filter coefficient module (ie, the shaped filter calculation module in FIG. 9).

The main signal delay module performs a time delay on the signal of the clipping peak to ensure that the generated cancellation pulse is aligned with time. The peak search module uses a certain algorithm to find the large peak of the signal in order to generate the cancellation pulse. The shaping filter calculation module is to prevent the ACLR of the signal after the peak clipping from deteriorating, and to generate a filter coefficient matching the main link signal in real time.

10 is a structural diagram of a peak search module for peak search based on a minimum phase error method according to an embodiment of the present invention. As shown in FIG. 10, the peak search module mainly includes digital up-conversion, phase separation of a signal and a modulus value, and minimum phase error. Peak search, phase extraction, hard clipping, IQ complex signal synthesis, the peak search module mainly performs the following operations:

Step 1: Perform multi-stage interpolation on the signal entering the peak clipping to perform large peak estimation, and the interpolation multiple can be flexibly selected according to the total bandwidth of the signal;

Step 2, using a digital signal processing algorithm for the IQ complex signal to perform modulus and phase separation, respectively obtaining the modulus value and phase of the signal, wherein the modulus value is used for peak search, the phase is delayed, and sent to the phase extraction module; the module The modulus and phase separation algorithms of the used signals include, but are not limited to, multi-level cordic iterative algorithms;

Step 3, performing peak search according to the modulus value of the signal, mainly including peak grouping and peak drawing, and specific implementation details will be detailed in FIG. 11;

Step 4, according to the address of the large peak signal outputted in step 3, phase extraction, and the extracted phase is sent to the IQ complex signal synthesis module;

Step 5, subtracting the searched large peak signal from a preset peak clipping threshold to generate a noise signal to be cancelled;

Step 6. Synthesize the IQ complex signal by using the digital signal processing algorithm after the hard clipping peak and the corresponding extracted phase for filtering processing with the shaping filter coefficients. The above digital signal processing algorithms include, but are not limited to, a multi-level cordic iterative algorithm and the like.

11 is a structural diagram of a minimum phase error peak search module for peak search based on a minimum phase error method, mainly including two modules of peak grouping and peak extraction, in accordance with an embodiment of the present invention.

The peak grouping module groups the peak signals after multi-stage upsampling according to the principle of ensuring the minimum phase error of all the peaks and the main signal before the upsampling, and the length of the signals in the group is a multiple of the multi-level interpolation, in each group, according to the cutting The peak-to-peak ratio of the peak is more than the adaptive configuration grouping parameter. The peak value after interpolation and the position of the main signal before interpolation are configured according to the grouping parameters. By such grouping, the phase error of the peak value of all signals and the main signal is optimized.

The peak extraction module filters the peak signals in each group, performs peak extraction according to the principle of maximum peak value, and sends the extracted peak address to the phase extraction module. After the extraction, the peak signal is consistent with the peak signal rate of the peak clipping. Peak clipping scheme at low rate under high rate.

The present invention has been described in detail by way of specific embodiments thereof, and the description of the embodiments may be made by those skilled in the art. The invention is not limited to peak clipping in a single frequency band, and is applicable and compatible for both dual-band and multi-band application scenarios. The present invention is not limited to correcting the suppression of the peak-to-average ratio of signals in a communication system, and is used for other scenarios involving single carrier and multi-carrier reduction peak-to-average ratio.

It should be noted that each of the above modules may be implemented by software or hardware. For the latter, the foregoing may be implemented by, but not limited to, the foregoing modules are all located in the same processor; or, the modules are located in multiple In the processor.

Embodiments of the present invention also provide a storage medium. Optionally, in the embodiment, the foregoing storage medium may be configured to store program code for performing the following steps:

S1, interpolating a first digital signal having N points, to obtain a second digital signal, wherein each point in the first digital signal is interpolated into M points, wherein N and M are both greater than or equal to 2, The phase difference between two adjacent points of the M points is Q;

S2, dividing N*M points in the second digital signal into N groups in sequence, wherein N points in the first digital signal are located at positions other than the two end points in the corresponding group;

S3, selecting a point with the largest amplitude from each of the N packets to obtain a third digital signal, wherein a phase between each point in the third digital signal and a corresponding point among the N points The difference is less than (M-1)*Q;

S4, performing peak clipping processing on the first digital signal according to the third digital signal.

Optionally, in the embodiment, the foregoing storage medium may include, but is not limited to, a USB flash drive, a Read-Only Memory (ROM), and a Random Access Memory (RAM). A variety of media that can store program code, such as a hard disk, a disk, or an optical disk.

Optionally, in the embodiment, the processor executes S1-S4 according to the stored program code in the storage medium.

For example, the specific examples in this embodiment may refer to the examples described in the foregoing embodiments and the optional embodiments, and details are not described herein again.

In summary, the minimum phase error search method proposed in the embodiment of the present invention has the following advantages compared with the conventional peak search method currently used in the industry. First, the multi-stage interpolation filter peak estimation technique is used, and the signal is based on the signal. The bandwidth is flexibly configured with interpolation multiples, which effectively avoids peak regeneration after peak clipping; secondly, a minimum phase error based The peak search algorithm improves the EVM index of the wideband signal after peak clipping under the premise of ensuring the peak-to-average ratio. The third is that the invention considers the use of resources at the time of implementation, and adopts a method of high-speed peak-searching and low-speed peak clipping to effectively reduce the logic resources. Overhead, significantly reducing costs.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

As described above, the digital signal processing method and apparatus provided by the embodiments of the present invention have the following beneficial effects: solving the problem that the phase error between the canceling pulse and the main signal is large when the peak clipping is performed in the related art, and further The effect of reducing the phase error between the cancellation pulse and the main signal is achieved.

Claims

A digital signal processing method includes:

Interpolating a first digital signal having N points to obtain a second digital signal, wherein each point in the first digital signal is interpolated into M points, wherein N and M are both greater than or equal to 2, The phase difference between two adjacent points in the M points is Q;

N*M points in the second digital signal are sequentially divided into N packets, wherein the N points in the first digital signal are located in the corresponding group except for two endpoints Position

Selecting a point having the largest amplitude from each of the N packets to obtain a third digital signal, wherein each point in the third digital signal and a corresponding one of the N points The phase difference between them is less than (M-1)*Q;

And performing peak clipping processing on the first digital signal according to the third digital signal.
The method of claim 1, wherein peak clipping the first digital signal based on the third digital signal comprises:

Finding, from the third digital signal, a point whose amplitude is greater than or equal to a first threshold and a point smaller than the first threshold;

Setting a magnitude of a point smaller than the first threshold to 0, and decreasing a magnitude of the point greater than or equal to the first threshold by the first threshold to obtain a fourth digital signal;

Performing peak clipping processing on the first digital signal using the fourth digital signal, wherein the peak clipping process is for reducing a point of the first digital signal corresponding to the point equal to or greater than the first threshold Amplitude.
The method of claim 2, wherein peak clipping the first digital signal using the fourth digital signal comprises:

Subtracting the fourth digital signal from the first digital signal to obtain a fifth digital signal after peak clipping; or

The fourth digital signal is filtered to obtain a sixth digital signal, and the sixth digital signal is subtracted from the first digital signal to obtain a peaked seventh digital signal.
The method of claim 1 wherein

Interpolating the first digital signal having N points, and obtaining the second digital signal comprises: setting an ith point in the first digital signal to a number in the second digital signal ((i- 1) *M+1) a point at which (M-1) points generated by interpolating the i-th point in the first digital signal are set in the second digital signal ( (i-1)*M+1) between the points and the ((i)*M+1) points, where 1≤i≤N;

The dividing the N*M points in the second digital signal into N groups in sequence includes: setting a first point to a Pth point in the second digital signal to the N groups The first grouping in which 2 ≤ P ≤ (M-1); the ((P+1)+(j-2)*M) points in the second digital signal to the (( P+1)+(j-1)*M-1) points are set to the jth group, where 2≤j≤N.
The method of claim 4 wherein said
The method of claim 1, wherein selecting a point having the largest amplitude from each of the N packets, the third digital signal comprising:

Obtaining the magnitude and phase of each point in each of the N packets;

Obtaining a magnitude of a point having the largest amplitude from each of the packets;

A point in the third digital signal is generated according to the obtained amplitude of the point having the largest amplitude and the corresponding phase.
A digital signal processing device comprising:

An interpolation module configured to interpolate a first digital signal having N points to obtain a second digital signal, wherein each point in the first digital signal is interpolated into M points, wherein N and M are Greater than or equal to 2, the phase difference between two adjacent points of the M points is Q;

a dividing module, configured to sequentially divide N*M points in the second digital signal into N packets, wherein the N points in the first digital signal are located in a corresponding group except two At a location other than the endpoint;

a selection module, configured to select a point having the largest amplitude from each of the N packets to obtain a third digital signal, wherein each of the third digital signals and the N points The phase difference between the corresponding points in the middle is less than (M-1)*Q;

The processing module is configured to perform peak clipping processing on the first digital signal according to the third digital signal.
The apparatus of claim 7 wherein said processing module comprises:

a searching unit, configured to search, from the third digital signal, a point whose amplitude is greater than or equal to a first threshold and a point smaller than the first threshold;

a setting unit, configured to set a magnitude of a point smaller than the first threshold to 0, and decrease a magnitude of the point greater than or equal to the first threshold by the first threshold to obtain a fourth digital signal;

a processing unit configured to perform peak clipping processing on the first digital signal using the fourth digital signal, wherein the peak clipping process is used to reduce the first digital signal and the first threshold The amplitude of the point corresponding to the point.
The apparatus of claim 8 wherein said processing unit comprises:

Processing the subunit, configured to subtract the fourth digital signal from the first digital signal to obtain a fifth digital signal after clipping; or

The filtering subunit is configured to filter the fourth digital signal to obtain a sixth digital signal, and subtract the sixth digital signal from the first digital signal to obtain a peaked seventh digital signal.
The apparatus according to claim 7, wherein

The interpolation module is configured to interpolate the first digital signal to obtain the second number a word signal: setting an ith point in the first digital signal to a ((i-1)*M+1)th point in the second digital signal, to be in the first digital signal (M-1) points generated by the interpolation of the i-th point are set at ((i-1)*M+1) points and ((i)*) in the second digital signal M+1) between points, where 1≤i≤N;

The dividing module is configured to sequentially divide N*M points in the second digital signal into N groups by: setting a first point to a Pth point in the second digital signal Is the first one of the N packets, where 2 ≤ P ≤ (M-1); the ((P+1)+(j-2)*M) of the second digital signal The points to the ((P+1)+(j-1)*M-1) points are set to the jth group, where 2≤j≤N.
The device of claim 10 wherein said
The apparatus of claim 7, wherein the selection module comprises:

a first obtaining unit, configured to acquire a magnitude and a phase of each point in each of the N packets;

a second obtaining unit, configured to obtain a magnitude of a point having the largest amplitude from each of the groups;

And generating a unit, configured to generate a point in the third digital signal according to the obtained amplitude of the point with the largest amplitude and a corresponding phase.