CN101237435B - A method and device for reducing multi-carrier signal peak equal ratio - Google Patents

Abstract

The invention relates to a system for sending a digital signal and a method thereof, in particular to a method for decreasing the multi-carrier signal PAR and a device thereof, comprising a device for decreasing the multi-carrier signal PAR. The device comprises a hard-limiting module, two delay modules, a carrier power estimation module, a matched filtering module and two summation modules. A CORDIC mode is applied to the hard-limiting process, thereby decreasing the complexity of the hard implementation and reducing the resources consumption. The matched filter processing module is realizedby changing a peak noise signal into a baseband by a matched filter bank. The invention regulates the gaining of the adjustable filter parameter of the filter bank of the corresponding carrier according to the power estimation value of each carrier base band signal, and does the digital intermediate frequency matched filtering despicking process on the combined multi-carrier signal, thereby avoiding the phenomenon of the signal distortion caused by using the same matched filter gain on the carriers with different power.

Description

A kind of method and apparatus that reduces the multi-carrier signal peak equal ratio

Technical field

The present invention relates to send the system and method for digital signal, more particularly, is the method and apparatus that reduces the signal peak-to-average ratio of ingoing power amplifier in the communication system, in particular a kind of peak clipping technology that reduces the multi-transceiver combination signal peak-to-average ratio.

Background technology

The sender of wireless base station utilizes power amplifier to transmit in the communication system, to compensate the signal attenuation that brings because of propagation distance.The input signal that peak-to-average force ratio is big has reduced the efficient of power amplifier, and as far as the multi-transceiver combination signal, such as CDMA access system, it is particularly outstanding that this problem seems.

In GSM; Usually reduce the signal peak-to-average ratio of ingoing power amplifier with the peak clipping technology; To improve the efficient of power amplifier, still also can bring problems such as distorted signals, out of band spectrum expansion or monkey chatter to a certain degree, emitting performance is descended.In CDMA access system (like WCDMA and cdma2000), come the distortion level of gauge signal usually with Error Vector Magnitude, leak the out of band spectrum degree of expansion that recently characterizes transmitter with adjacent-channel power.

Base band peak clipping and digital intermediate frequency peak clipping are two types of main peak clipping technology in the communication system; Base band peak clipping technology is before the pulse-shaping filter, to carry out peak clipping to handle; Therefore can not bring any out of band spectrum expansion or adjacent-channel power to leak; Its shortcoming is that peak-to-average force ratio will increase behind the peak clipping signal process digital intermediate frequency multilevel interpolation filter, and it is good inadequately to the inhibition of signal peak-to-average ratio to make.In addition, base band peak clipping meeting causes bigger distorted signals, and it is obvious to show as the Error Vector Magnitude decreased performance.Under the prerequisite that satisfies the Error Vector Magnitude performance, the base band peak clipping is difficult to make signal peak-to-average ratio after the Digital IF Processing to reach the index request of expection.

The digital intermediate frequency peak clipping is carried out the peak clipping processing after being meant the multilevel interpolation filter of baseband signal through digital intermediate frequency again, and intermediate frequency peak clipping commonly used has hard peak clipping and matched filtering peak clipping etc.The advantage of the hard peak clipping technology of intermediate frequency is that hardware realizes comparatively simple, and shortcoming is that it directly carries out digital intermediate frequency hard-limiting peak clipping processing, can cause serious adjacent-channel power leakage phenomenon.But leak than performance index if will guarantee to satisfy adjacent-channel power, the hard peak clipping technology of intermediate frequency then is difficult to reach the peak-to-average force ratio performance of expection.

One Chinese patent application number is that the peak clipping technology that 03804978.3 application for a patent for invention is used just belongs to digital intermediate frequency matched filtering peak clipping technology; This patent application designs to multi-carrier signal peak clipping situation; The baseband filter of a digital intermediate frequency correspondence of design earlier sample frequency; The baseband filter shift frequency after corresponding carrier frequency, is obtained closing path filter to the filter addition behind the shift frequency again, the peak value offset signal is carried out matched filtering with closing path filter.When input is closed the sample frequency of way word intermediate-freuqncy signal when big, for example 12 times or bigger, the tap number of filter is required very high, this has increased the cost and the difficulty of hardware realization (FPGA or ASIC).

In addition; Though when this technical scheme has been considered each carrier wave matched filter coefficient generation suitable adjustment is carried out in its gain; Unify gain adjustment more performance to obtain than only to use scaler; But explanation is not specifically how to the adjustment that gains of each carrier wave matched filter coefficient, and how in real time each carrier wave matched filter coefficient to be adjusted, and especially how this adjusts each matched filter gain in system's realization.

Summary of the invention

In order to overcome the problem that exists in the prior art, the present invention proposes a kind of method and apparatus that reduces the multi-carrier signal peak equal ratio, and the present invention specifically is achieved in that

A kind of device that reduces the multi-carrier signal peak equal ratio comprises: hard-limiting module, two Postponement modules, carrier power estimation module, matched filter processing module and two summation accumulator module;

Said hard-limiting module; According to threshold value the multi-transceiver combination signal of input is handled; Adopt rotation of coordinate numerical calculation mode producing hard-limiting signal; Said hard-limiting module further comprises: the amplitude computing unit of multi-transceiver combination signal, produce the amplitude limit unit of hard-limiting signal with the comparison of threshold parameter and decision unit with according to threshold parameter; Wherein, said rotation of coordinate numerical calculation pattern is: (1) obtains the amplitude of each input sample signal with rotation of coordinate compute vectors pattern, preserves the rotation parameter that per step calculates; (2) realize that with rotation of coordinate compute vectors pattern Cartesian coordinate is to polar conversion; (3), obtain the amplitude and rotation gain of input sample signal after the rotation of employing rotation of coordinate computation schema according to given multi-transceiver combination signal; (4) product with the gain of the rotation in the amplitude that obtains in the step (1) and threshold value and the step (3) compares: if the amplitude that obtains in the step (1) is not more than the product of the rotation gain in threshold value and the step (3), then the hard-limiting signal is input multi-transceiver combination signal; Otherwise; Ratio and 0 with the gain of the rotation in threshold value and the step (3) is that initial parameters is utilized the despining of rotation of coordinate computation schema respectively; And the rotation parameter of preserving during according to rotation of coordinate compute vectors mode computation calculates the hard-limiting signal, and wherein the rotation parameter of every grade of use of rotation of coordinate computation schema despining must align with the rotation of coordinate arrow pattern;

A said summation accumulator module produces multicarrier peak value offset signal to the hard-limiting signal with through the multi-transceiver combination signal subtraction that a Postponement module is handled;

Said carrier power estimation module is according to the power of each carrier wave of multicarrier baseband signal estimation; Said matched filter processing module is carried out matched filtering to the peak value offset signal of each carrier wave;

A said summation accumulator module produces the multi-carrier peak-clipping signal to filtered multicarrier peak value offset signal and the multi-transceiver combination signal plus of handling through another Postponement module.

Iteration means is used to carry out the multi-transceiver combination signal and carries out multistage peak clipping processing.

Said matched filter processing module further comprises: two mixing unit, at least one matched filter banks, the summation unit that adds up; A said mixing unit carries out down-conversion with the negative frequency of each carrier wave respective frequencies to the peak value offset signal and obtains corresponding baseband signal; Said matched filter banks is carried out filtering and is fallen sampling, gain-adjusted, liter sampling and Filtering Processing each roadbed band signal; A said mixing unit, each carrier wave respective frequencies of usefulness is carried out upconversion process to the output signal of each road matched filter banks; The said summation unit that adds up, the summation of the output result after each road up-conversion added up obtains filtered multicarrier peak value offset signal.

Said matched filter banks comprises: two filtering and 2 times fall sampling unit, Gain Adjustable filter and two 2 times and rise appearance and filter unit; Gain Adjustable filter wherein carries out gain-adjusted according to the estimated value of each carrier power of correspondence to filter.Said Gain Adjustable filter can adopt approximate square filtering device.

A kind of method that reduces the multi-carrier signal peak equal ratio comprises the steps:

Step 1, according to multi-transceiver combination signal and threshold value, produce the hard-limiting signal; Said step 1 further comprises: (1) obtains the amplitude of each input sample signal with rotation of coordinate compute vectors pattern, preserves the rotation parameter that per step calculates; (2) realize that with rotation of coordinate compute vectors pattern Cartesian coordinate is to polar conversion; (3), obtain the amplitude and rotation gain of input sample signal after the rotation of employing rotation of coordinate computation schema according to given multi-transceiver combination signal; (4) product with the gain of the rotation in the amplitude that obtains in the step (1) and threshold value and the step (3) compares: if the amplitude that obtains in the step (1) is not more than the product of the rotation gain in threshold value and the step (3), then the hard-limiting signal is input multi-transceiver combination signal; Otherwise; Ratio and 0 with the gain of the rotation in threshold value and the step (3) is that initial parameters is utilized the despining of rotation of coordinate computation schema respectively; And the rotation parameter of preserving during according to rotation of coordinate compute vectors mode computation calculates the hard-limiting signal, and wherein the rotation parameter of every grade of use of rotation of coordinate computation schema despining must align with the rotation of coordinate arrow pattern.

Step 2, produce the peak value offset signal according to multi-transceiver combination signal after postponing and hard-limiting signal;

Step 3, estimate the power of each carrier wave according to the multicarrier baseband signal;

Step 4, multicarrier peak value offset signal is carried out matched filter processing;

Step 5, the summation of filtered peak value offset signal and multi-transceiver combination signal added up obtains the multi-carrier peak-clipping signal.

The method of described reduction multi-carrier signal peak equal ratio further comprises: the multi-transceiver combination signal is carried out multistage peak clipping iterative processing.

Said step 1 further comprises:

(1) adopts the rotation of coordinate computation schema to calculate to the multi-transceiver combination signal, obtain amplitude, phase place and the rotation gain of each input sample signal;

(2) product with amplitude and threshold value and rotation gain compares:

If amplitude is not more than the product of threshold value and rotation gain, then the hard-limiting signal is input multi-transceiver combination signal;

Otherwise then the employing of rotation of coordinate compute vectors pattern is that the initial seat parameter of using obtains the hard-limiting signal with the ratio and the phase place of threshold value and rotation gain.

Said step 4 further comprises:

(1) with the negative frequency of each carrier wave respective frequencies the peak value offset signal is carried out down-conversion and obtain corresponding baseband signal;

(2) each roadbed band signal is carried out filtering and falls sampling, adjustable filtering, liter sampling and Filtering Processing;

(3) regulate the gain of tunable filter according to the carrier power estimated value;

(4) frequency that each carrier wave of usefulness is corresponding is carried out up-conversion to the output signal of each road matched filter banks;

(5) summation of the output after each road up-conversion adds up and obtains filtered multicarrier peak value offset signal.

The present invention according to each carrier wave power of baseband signal estimated value to the adjustment that gains of the bank of filters tunable filter coefficient of corresponding carriers; Multi-carrier signal behind the involutory road carries out digital intermediate frequency matched filtering peak clipping to be handled, and has avoided the distorted signals energy imbalance that uses the identical match filter gain to bring to the different carrier wave of power.The present invention can obtain better peak clipping effect satisfying under the condition that same error amplitude of the vector and adjacent-channel power leak ratio, also can make the multi-transceiver combination signal after the peak clipping have lower peak-to-average force ratio.

The hard-limiting method that the present invention adopts is different with traditional implementation method, and rotation of coordinate numerical calculation (CORDIC) pattern is applied in the hard-limiting processing, has reduced hard-wired complexity and resource consumption; The matched filter processing module is through realizing to base band peak value offset signal transformation with matched filter banks; Reduced the multiplier resources that traditional matched filtering method needs largely, and adjustable filter design method has been improved the effect of peak clipping in the matched filter banks.

When Digital IF Processing, if will when obtaining higher sampling rate, consider the saving of hardware resource again; Can use the two-stage semi-band filter; In addition, design matched filter banks, if satisfying the leakage of Error Vector Magnitude and adjacent-channel power than under the condition according to concrete if sampling speed; Hope to obtain lower peak-to-average force ratio performance

The suitably used multi-stage iteration peak clipping of the present invention is handled, and its Digital Signal Processing adopts the sequential processes mode, does not relate to any feedback processing modules, easily in the actual hardware system, adopts streamline to realize.

Description of drawings

Fig. 1 is that multi-carrier signal forms and the sketch map of multicarrier peak value peak-clipping module present position among the present invention;

Fig. 2 makes specific embodiment of the present invention, with the amplitude-frequency response of the RRC filter after the compensation CIC gain in the concrete implementation structure shown in Figure 1;

Fig. 3 is the basic structure that the multi-carrier peak-clipping that is used to reduce the multi-carrier signal peak equal ratio of the present invention is realized;

Fig. 4 (a) and (b) are the hard-limiting implementation methods in the structure shown in Figure 3;

Fig. 5 is the concrete realization of the matched filter processing of basic structure shown in Figure 3;

Fig. 6 is the concrete implementation structure of matched filter banks corresponding in the matched filter processing module shown in Figure 5;

Fig. 7 is the amplitude-frequency response contrast properties of RRC of the present invention and square filter;

Fig. 8 is that the another kind of of basic structure shown in Figure 3 specifically realized;

Fig. 9 is that the multi-transceiver combination signal is through the CCDF curve before and after the multi-carrier peak-clipping of the present invention.

Embodiment

The present invention combines accompanying drawing that embodiment is described in detail.

In the base station transmitter of wireless communication system, use peak clipping technology reduces the peak-to-average force ratio of the multi-transceiver combination signal of ingoing power amplifier, to improve the efficient of power amplifier.Fig. 1 is that multi-carrier signal forms and the sketch map of multicarrier peak value peak-clipping module present position among the present invention.As far as every road carrier wave; Its baseband complex signal is carried out pulse-shaping filtering through the root raised cosine interpolation filter (CRRC) of compensation; Through the sampling rate of semi-band filter (HBF) with the raising digital medium-frequency signal; The mirror image of signal in frequency domain suppressed to strengthen through range upon range of integration pectination interpolation filter (CIC), and carry out the output of mixing formation single carrier digital medium-frequency signal with digital controlled oscillator, each carrier wave digital medium-frequency signal merges to produce multi-transceiver combination output signal at last.

Realize the cost of storage list in order to reduce hardware, the NCO frequency that four carrier waves can be set is symmetrical, for example respectively with f ₁, f ₂, f ₃And f ₄Be set to f ₁, f ₂,-f ₂With-f ₁, like this, f ₁With-f ₁NCO can shared lookup table (LUT).Further, if need obtain higher sampling rate and reduce the hardware implementation complexity, can adopt the two-stage semi-band filter in Digital IF Processing.

In digital medium-frequency signal interpolation and filter process, realize cost and good mirror image rejection is provided though use cic filter to reduce hardware, also can cause the unevenness of gain in the band simultaneously.In order to make whole digital intermediate frequency interpolation and Filtering Processing have the interior gain flatness of band preferably, compensate the interior gain unevenness of band of cic filter through the RRC filter (CRRC) of design compensation.

Shown in Figure 2 is amplitude-frequency response according to the CRRC filter of Fig. 1 example design; Also provided the amplitude-frequency response characteristic of compensation front and back RRC filter and whole digital intermediate frequency filter (comprising CRRC, HBF and CIC) convolution results among Fig. 2; Can find out if RRC does not compensate the interior gain loss of the band of CIC, the inband flatness poor-performing of then whole digital intermediate frequency filter convolution.

The basic structure that Fig. 3 realizes for the multi-carrier peak-clipping that is used to reduce the multi-carrier signal peak equal ratio of the present invention.Multi-carrier peak-clipping device among Fig. 3 is made up of a hard-limiting module, two Postponement modules, a carrier power estimation module, a matched filter processing module and two summation accumulator module.

The hard-limiting module is carried out the hard-limiting processing according to threshold parameter to input multi-transceiver combination signal, to produce the hard-limiting signal.Said Postponement module postpones to handle to the multi-transceiver combination signal.The hard-limiting signal deducts through the multi-transceiver combination signal behind the Postponement module, to produce the peak value offset signal.A said summation accumulator module produces multicarrier peak value offset signal to the hard-limiting signal with through the multi-transceiver combination signal subtraction that a Postponement module is handled; The matched filter processing module is carried out matched filtering to the peak value offset signal, obtains filtered multicarrier peak value offset signal.The carrier power estimation module is used to estimate that each carrier wave baseband signal power estimates.Said another summation accumulator module, the multi-transceiver combination signal after the delayed module and filtered multicarrier peak value offset signal sued for peace to add up produces the multi-carrier peak-clipping signal.

Said hard-limiting module further comprises, the amplitude computing unit of multi-transceiver combination IQ signal, produces the amplitude limit unit of hard-limiting signal with the comparison of threshold parameter and decision unit and according to threshold parameter.

Said matched filter processing module comprises, with the negative frequency of each carrier wave respective frequencies the peak value offset signal is carried out the mixing unit that down-conversion obtains corresponding baseband signal; Each roadbed band signal is carried out filtering and the matched filter banks of falling sampling, adjustable filtering, liter sampling and filtering, according to the gain adjustment unit of carrier power estimated value adjustment tunable filter; The output signal of each road matched filtering group is carried out the mixing unit of up-conversion with each carrier wave respective frequencies; The summation unit that adds up with output addition after each road up-conversion.

The method of reduction multi-carrier signal peak equal ratio of the present invention comprises, produces the hard-limiting signal according to multi-transceiver combination signal and threshold parameter; Produce the peak value offset signal according to multi-transceiver combination signal after postponing and hard-limiting signal; Estimate the power of each carrier wave according to the multicarrier baseband signal; Multicarrier peak value offset signal is carried out matched filter processing; Filtered peak value offset signal and the summation of multi-transceiver combination signal add up and obtain the multi-carrier peak-clipping signal.

Said hard-limiting is handled and further comprised: the amplitude of multi-transceiver combination IQ signal calculates, produce the hard-limiting signal with the comparison of threshold parameter and judgement and according to threshold parameter.Wherein Fig. 4 is the sketch map of the hard-limiting method implementation procedure in the structure shown in Figure 3, (a) illustrates the process of using rotation of coordinate numerical calculation (CORDIC) mode computation multi-transceiver combination signal amplitude, obtains signal amplitude

With the direction of rotation parameter d _n, this amplitude result is a signal amplitude

K doubly (K comes from the processing gain of cordic algorithm), d here _nDepend on y _nSymbol (if y _n＜0 o'clock d _nGet 1, otherwise d _nGet-1), every grade the anglec of rotation is respectively d _n* arctan 2 ^-n(b) figure is the d according to Thr/K and preservation _nParameter is carried out the CORDIC despining and is produced hard-limiting output signal (Thr*cos φ _kWith Thr*sin φ _k, ${\mathrm{\φ}}_k=\mathrm{Arctan}\frac{Q_k^{\mathrm{Sum}}}{I_k^{\mathrm{Sum}}}$ ) process, every grade the anglec of rotation is respectively-d _n* arctan2 ^-n, every grade d during despining _nBe rotated in the forward identical.

Multi-carrier peak-clipping device of the present invention not only can be applicable to multi-carrier communications systems, and the present invention carries out suitable modification and cutting according to hardware resource and the performance requirement in the practical communication system design, also applicable to carrier wave communication system.If only need support single carrier, then can crop the up-conversion part relevant with down-conversion, can significantly reduce hardware resource consumption like this.

Shown in Figure 5 is the realization example of the matched filter processing of employing according to the present invention.Said matched filter processing further comprises: with the negative frequency of each carrier wave respective frequencies the peak value offset signal is carried out down-conversion respectively and obtain the corresponding base band signal; Each roadbed band signal respectively through matched filter banks, is carried out filtering and the processing of falling sampling, adjustable filtering, liter sampling and filtering; Regulate the gain of respective channel matched filter banks tunable filter according to the carrier power estimated value; With each carrier wave respective frequencies up-conversion is carried out in each passage matched filter banks output; Output result after the up-conversion of each passage sued for peace add up, obtain filtered multicarrier peak value offset signal.

Shown in Figure 6 is the realization example that adopts the matched filter banks of the corresponding multi-carrier peak-clipping module of 12 multiple word if samplings according to the present invention; Matched filter banks comprises that gain adjustment unit and two 2 times that sampling unit, an adjustment Gain Adjustable filter fall in two filtering and 2 times rise sampling and form with filter unit, and gain adjustment unit is then carried out gain-adjusted according to the carrier power estimated value of correspondence.Gain Adjustable Design of Filter in the matched filter banks is approximate square filtering device (non-traditional RRC filter), to improve the multi-carrier peak-clipping performance.

Shown in Figure 7 is the amplitude-frequency response contrast properties of RRC of the present invention and square filter.Can find out among Fig. 7 that the occupied bandwidth of square filtering device is greater than the RRC filter, this helps improving the peak clipping performance.

Consider the Mathematical Modeling of four carrier communication systems among the present invention.Describe for ease and represent, use different mathematic signs to represent the signal of each stage or module below, represent carrier index, baseband sampling index and if sampling index with i, j and k respectively.

1) baseband I Q signal: I _{I, j} ^Bb, Q _{I, j} ^Bb

2) the corresponding intermediate-freuqncy signal of each carrier wave: I behind the filtering interpolation _{I, k} ^Dif, Q _{I, k} ^Dif

3) multi-transceiver combination signal: I _k ^Sum, Q _k ^Sum

4) threshold parameter: Thr

5) hard-limiting signal: I _k ^Hard_clip, Q _k ^Hard_clip

6) multicarrier peak value offset signal: I _k ^Peak_noise, Q _k ^Peak_noise

7) the corresponding peak value offset signal of each carrier wave: I after the down-conversion _{I, k} ^Down_shift, Q _{I, k} ^Down_shift

8) the corresponding peak value offset signal of each carrier wave: I after the matched filtering _{I, k} ^Filter_bank, Q _{I, k} ^Filter_bank

9) the corresponding peak value offset signal of each carrier wave: I after the up-conversion _{I, k} ^Up_shift, Q _{I, k} ^Up_shift

10) filtered multicarrier peak value offset signal: I _k ^{Final_peak_noise}, Q _k ^{Final_peak_noise}

11) multi-carrier peak-clipping signal: I _k ^Clipped, Q _k ^Clipped

Each carrier wave baseband I Q signal produces digital intermediate frequency sampled signal I through multilevel interpolation filtering (CRRC, HBF and CIC) back _{I, k} ^DifAnd Q _{I, k} ^Dif, produce multi-transceiver combination signal I with corresponding carrier frequency mixing and addition _k ^SumAnd Q _k ^SumFour carrier waves before the four carrier wave peak-clipping modules close the road signal and can be expressed as:

$I_k^{\mathrm{Sum}}+j*Q_k^{\mathrm{Sum}}=\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}(I_{i,k}^{\mathrm{Dif}}+j*Q_{i,k}^{\mathrm{Dif}})*{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="H07102958420070201E000022.png,H07102958420070201E000031.png"\; state="\{\{state\}\}">e</figure-callout>}}^j$ (formula 1)

Hard-limiting among Fig. 3 of the present invention can adopt cordic algorithm to realize.At first to each input sample signal I _k ^SumAnd Q _k ^SumAdopt the CORDIC arrow pattern to obtain amplitude A _k $(A_k=K*\sqrt{{\left(I_k^{\mathrm{Sum}}\right)}^2+{\left(Q_k^{\mathrm{Sum}}\right)}^2})$ And phase _kWith A _kCompare with Thr*K; If A _kBe less than or equal to Thr*K, then the hard-limiting signal is input multi-transceiver combination signal; If A _kGreater than Thr*K, then use the CORDIC rotary mode with Thr/K and φ _k(being calculated by the CORDIC arrow pattern) obtains the hard-limiting signal for initial parameters.

Hard-limiting among Fig. 3 of the present invention also can adopt the cordic algorithm of correction to realize, can save 1/3 hardware circuit resource, to reduce hardware implementation cost.Description below Fig. 4 and combination can be readily appreciated that hard-limiting implementation method of the present invention.At first calculate the amplitude A of each input sample signal with the CORDIC arrow pattern _k, preserve the d of per step calculating _nFor the CORDIC despining usefulness of back, and need not calculate phase term φ _kThe CORDIC arrow pattern realizes that Cartesian coordinate to polar conversion, is formulated as:

$\left\{\begin{array}{c}{x}_{n+1}=x_n-d_n\&CenterDot;y_n\&CenterDot;2^{-n}\\ y_{n+1}=y_n+d_n\&CenterDot;x_n\&CenterDot;2^{-n}\end{array}\right.n\&GreaterEqual;0$ (formula 2)

D in the formula 2 _nDepend on y _nSymbol:

$d_n=\left\{\begin{array}{cc}1& y_n<0\\ -1& y_n\&GreaterEqual;0\end{array}\right.$ (formula 3)

Given $x_0=I_k^{\mathrm{Sum}}$ With ${\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="H07102958420070201E000012.png,H07102958420070201E000052.png"\; state="\{\{state\}\}">y</figure-callout>}}_0=Q_k^{\mathrm{Sum}},$ Through obtaining after the CORDIC rotation:

$x_{n+1}=K\&CenterDot;\sqrt{{x_0}^2+{{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="H07102958420070201E000012.png,H07102958420070201E000052.png"\; state="\{\{state\}\}">y</figure-callout>}}_0}^2}$

y _N+1=0 (formula 4)

$K=\underset{n=0}{\overset{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="H07102958420070201E000012.png,H07102958420070201E000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{\mathrm{\&Pi;}}}\sqrt{1+2^{-2n}}$

In the formula 4, N is the progression (N gets 8 and just can obtain excellent precision usually) of CORDIC rotation, x _N+1Be input sample signal I _k ^SumAnd Q _k ^SumThe amplitude of behind CORDIC, calculating is with A _kCompare with Thr*K (K is the gain of CORDIC rotation); If A _kBe less than or equal to Thr*K, then the hard-limiting signal is input multi-transceiver combination signal; If A _kGreater than Thr*K, x ₀And y ₀Be that initial parameters is carried out the CORDIC despining with Thr/K and 0 respectively, and the d that preserves when calculating according to the CORDIC arrow pattern _nParameter is calculated the hard-limiting signal.The d of every grade of use of CORDIC despining _nMust align with the CORDIC arrow pattern.

$\left\{\begin{array}{c}{x}_{n+1}=x_n+d_n\&CenterDot;y_n\&CenterDot;2^{-n}\\ y_{n+1}=y_n-d_n\&CenterDot;x_n\&CenterDot;2^{-n}\end{array}\right.n\&GreaterEqual;0$ (formula 5)

Given x ₀=Thr/K and y ₀=0, then have:

x _n+1＝Thr·cosφ _k

y _N+1=Thrsin φ _k(formula 6)

$K=\underset{n=0}{\overset{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="H07102958420070201E000012.png,H07102958420070201E000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{\mathrm{\&Pi;}}}\sqrt{1+2^{-2n}}$

In the formula 6, x _N+1And y _N+1For corresponding carrier wave closes road signal I _k ^Sum, Q _k ^SumHard-limiting signal I _k ^Hard_clipAnd Q _k ^Hard_clip, φ _kBe I _k ^Sum, Q _k ^SumPhase place.

The hard-limiting signal deducts the multi-transceiver combination signal after the delay, then obtains multicarrier peak value offset signal:

$\left\{\begin{array}{c}{I}_k^{\mathrm{Peak}\_\mathrm{Noise}}=I_k^{\mathrm{Hard}\_\mathrm{Clip}}-I_k^{\mathrm{Sum}}\\ Q_k^{\mathrm{Peak}\_\mathrm{Noise}}=Q_k^{\mathrm{Hard}\_\mathrm{Clip}}-Q_k^{\mathrm{Sum}}\end{array}\right.$ (formula 7)

Carrier power estimation module among Fig. 3, the power of baseband signal that every carrier wave is corresponding calculates with formula 8:

$P_i^{\mathrm{Est}}=\frac{1}{N_{\mathrm{Samples}}}\underset{n=1}{\overset{N_{\mathrm{Samples}}}{\mathrm{\&Sigma;}}}({I_{i,\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H07102958420070201E000022.png,H07102958420070201E000031.png"\; state="\{\{state\}\}">n</figure-callout>}}}^2+{Q_{i,n}}^2),i=\mathrm{1,2,3,4}$ (formula 8)

In the formula 8, N _SamplesFor being used for the baseband sampling number that power is estimated, according to P _i ^EstTable look-up (LUT) obtain corresponding amplitude gain A _i ^Est

$A_i^{\mathrm{Est}}=\sqrt{P_i^{\mathrm{Est}}},i=\mathrm{1,2,3,4}$ (formula 9)

Use the negative frequency of carrier frequency that the peak value offset signal is carried out the baseband signal that down-conversion obtains correspondence:

$I_{i,k}^{\mathrm{Down}\_\mathrm{Shift}}+j*Q_{i,k}^{\mathrm{Down}\_\mathrm{Shift}}=(I_k^{\mathrm{Peak}\_\mathrm{Noise}}+j*Q_k^{\mathrm{Peak}\_\mathrm{Noise}})*e^{-2\mathrm{\&pi;}{f}_{i}k},i=\mathrm{1,2,3,4}$ (formula 10)

The baseband signal of down-conversion output is carried out matched filter processing through matched filter banks shown in Figure 6 respectively, and matched filter banks is handled the carrier power adjusting tunable filter gain that comprises according to estimating, obtains I _{I, k} ^Filter_bankAnd Q _{I, k} ^Filter_bank:

$\left\{\begin{array}{c}{I}_{i,k}^{\mathrm{Filter}\_\mathrm{Bank}}=\mathrm{Filter}\_\mathrm{Bank}\left(I_{i,k}^{\mathrm{Down}\_\mathrm{Shifted}}\right)*A_i^{\mathrm{Est}}\\ Q_{i,k}^{\mathrm{Filter}\_\mathrm{Bank}}=\mathrm{Filter}\_\mathrm{Bank}\left(Q_{i,k}^{\mathrm{Down}\_\mathrm{Shifted}}\right)*A_i^{\mathrm{Est}}\end{array}\right.$ (formula 11)

With corresponding carrier frequency the peak value offset signal is carried out down-conversion and obtains corresponding baseband signal:

$I_{i,k}^{\mathrm{Up}\_\mathrm{Shift}}+j*Q_{i,k}^{\mathrm{Up}\_\mathrm{Shift}}=(I_{i,k}^{\mathrm{Filter}\_\mathrm{Bank}}+j*Q_{i,k}^{\mathrm{Filter}\_\mathrm{Bank}})*{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="H07102958420070201E000022.png,H07102958420070201E000031.png"\; state="\{\{state\}\}">e</figure-callout>}}^{2\mathrm{\&pi;}{f}_{i}k},i=\mathrm{1,2,3,4}$ (formula 12)

Corresponding peak value offset signal summation adds up and produces filtered multicarrier peak value offset signal to each carrier wave after the up-conversion:

$\left\{\begin{array}{c}{I}_k^{\mathrm{Final}\_\mathrm{Peak}\_\mathrm{Noise}}=\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}{I}_{i,k}^{\mathrm{Up}\_\mathrm{Shift}}\\ Q_k^{\mathrm{Final}\_\mathrm{Peak}\_\mathrm{Noise}}=\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}{Q}_{i,k}^{\mathrm{Up}\_\mathrm{Shift}}\end{array}\right.$ (formula 13)

Postpone back multi-transceiver combination signal and filtered multicarrier peak value offset signal plus and obtain the multi-carrier peak-clipping signal:

$\left\{\begin{array}{c}{I}_k^{\mathrm{Clipped}}=I_k^{\mathrm{Sum}}+I_k^{\mathrm{Final}\_\mathrm{Peak}\_\mathrm{Noise}}\\ Q_k^{\mathrm{Clipped}}=Q_k^{\mathrm{Sum}}+Q_k^{\mathrm{Final}\_\mathrm{Peak}\_\mathrm{Noise}}\end{array}\right.$ (formula 14)

Shown in Figure 8 is a specific embodiment of the present invention, the concrete realization that the another kind of multi-carrier peak-clipping of basic structure shown in Figure 3 is handled.Concrete realization and Fig. 3 difference of Fig. 8 are; Can require and the hardware resource situation according to systematic function during system design; The multi-transceiver combination signal is carried out the multi-stage iteration peak clipping handle operation; Make satisfying under systematic error amplitude of the vector and adjacent-channel power leak than index condition, obtain more excellent peak clipping effect, guarantee that promptly the multi-carrier peak-clipping signal has littler peak-to-average force ratio.Among Fig. 8, multi-carrier peak-clipping modules at different levels also can use different threshold parameters as required, to obtain better peak clipping effect.

Fig. 9 shows four carrier wave WCDMA digital intermediate frequencies and closes the contrast situation of road signal through signal CCDF curve behind the peak-clipping module of the present invention.As can be seen from Figure 9, after the peak clipping not only peak-to-average force ratio significant minimizing is arranged, reduce to 5.7dB by the 9.8dB before the peak clipping (0.01%CCDF), signal CCDF curve is steepen also.Theory analysis and laboratory results show that CCDF curve precipitous after the peak clipping is of value to the efficient that improves power amplifier.With similar peak clipping compared with techniques; The multi-carrier peak-clipping technology of the present invention's sampling; Under guaranteeing that satisfy the systematic error amplitude of the vector leaks than index condition with adjacent-channel power, use still less hardware resource and the lower peak-to-average force ratio performance of acquisition, obtain higher power amplification efficiency more easily.

The present invention can carry out suitable modification and cutting according to hardware resource and the performance requirement in the practical communication system design.If only need support single carrier, then can crop the up-conversion part relevant with down-conversion, significantly reduced hardware resource consumption.During Digital IF Processing,, can use the two-stage semi-band filter if will when obtaining higher sampling rate, consider the saving of hardware resource again.If satisfying the leakage of Error Vector Magnitude and adjacent-channel power, hope to obtain lower peak-to-average force ratio performance, can suitably use multi-stage iteration peak clipping processing method to realize than under the condition.Scheme provided by the invention, its Digital Signal Processing adopts the sequential processes mode, does not relate to any feedback processing modules, thereby easily in the actual hardware system, realizes.

Here the present invention is described in detail through concrete examples of implementation; Provide the description of the foregoing description to make or be suitable for the present invention in order to make those skilled in the art, the various modifications of these embodiment are to understand easily for a person skilled in the art.The present invention is applicable to code division multiple access systems such as WCDMA, cdma2000.

Claims (8)

1. a device that reduces the multi-carrier signal peak equal ratio is characterized in that, comprising:

Hard-limiting module, two Postponement modules, carrier power estimation module, matched filter processing module and two summation accumulator module;

Said hard-limiting module; According to threshold value the multi-transceiver combination signal of input is handled; Adopt rotation of coordinate numerical calculation mode producing hard-limiting signal; Said hard-limiting module further comprises: the amplitude computing unit of multi-transceiver combination signal, produce the amplitude limit unit of hard-limiting signal with the comparison of threshold parameter and decision unit with according to threshold parameter; Wherein, said rotation of coordinate numerical calculation pattern is: (1) obtains the amplitude of each input sample signal with rotation of coordinate numerical calculation pattern, preserves the rotation parameter that per step calculates; (2) realize that with rotation of coordinate numerical calculation pattern Cartesian coordinate is to polar conversion; According to given multi-transceiver combination signal; After calculating the said given multi-transceiver combination signal of input, the amplitude of the input sample signal that after the rotation of rotation of coordinate numerical calculation pattern, obtains and rotation gain; (3) product with the gain of the rotation in the amplitude that obtains in the step (1) and threshold value and the step (2) compares: if the amplitude that obtains in the step (1) is not more than the product of the rotation gain in threshold value and the step (2), then the hard-limiting signal is input multi-transceiver combination signal; Otherwise, be that initial value is carried out the despining of rotation of coordinate numerical calculation pattern with the ratio and 0 of the gain of the rotation in threshold value and the step (2), wherein, the ratio and 0 of the rotation gain in said threshold value and the step (2) is respectively parameter x ₀With parameter y ₀Initial value,

With

Be the multi-transceiver combination signal; And the rotation parameter of preserving during according to rotation of coordinate numerical calculation mode computation calculates the hard-limiting signal, and wherein the rotation parameter of every grade of use of rotation of coordinate numerical calculation pattern despining must align with rotation of coordinate numerical calculation pattern;

A said summation accumulator module produces multicarrier peak value offset signal to the hard-limiting signal with through the multi-transceiver combination signal subtraction that a Postponement module is handled;

Said carrier power estimation module is estimated the power of each carrier wave according to the multicarrier baseband signal, and is given said matched filter processing module;

Said matched filter processing module is carried out matched filtering to the peak value offset signal of each carrier wave;

Said another summation accumulator module produces the multi-carrier peak-clipping signal to filtered multicarrier peak value offset signal and the multi-transceiver combination signal plus of handling through another Postponement module.

2. the device of reduction multi-carrier signal peak equal ratio as claimed in claim 1 is characterized in that, also comprises,

Iteration means is used to carry out the multistage peak clipping of multi-transceiver combination signal and handles.

3. according to claim 1 or claim 2 the device of reduction multi-carrier signal peak equal ratio is characterized in that said matched filter processing module further comprises:

Two mixing unit, at least one matched filter banks, the summation unit that adds up;

A said mixing unit carries out down-conversion with the negative frequency of each carrier wave respective frequencies to the peak value offset signal and obtains corresponding baseband signal;

Said matched filter banks is carried out filtering and is fallen sampling, gain-adjusted, liter sampling and Filtering Processing each roadbed band signal;

Said another mixing unit, each carrier wave respective frequencies of usefulness is carried out upconversion process to the output signal of each road matched filter banks;

The said summation unit that adds up, the summation of the output result after each road up-conversion added up obtains filtered multicarrier peak value offset signal.

4. the device of reduction multi-carrier signal peak equal ratio as claimed in claim 3 is characterized in that, said matched filter banks further comprises:

Two filtering and 2 times fall sampling unit, Gain Adjustable filter and two 2 times and rise sampling and filter unit;

Gain Adjustable filter wherein carries out gain-adjusted according to the estimated value of each carrier power of correspondence to filter.

5. the device of reduction multi-carrier signal peak equal ratio as claimed in claim 4 is characterized in that,

Said Gain Adjustable filter can adopt approximate square filtering device.

6. a method that reduces the multi-carrier signal peak equal ratio is characterized in that, comprises the steps:

Step 1, according to multi-transceiver combination signal and threshold value, produce the hard-limiting signal;

Said step 1 further comprises:

(1) obtains the amplitude of each input sample signal with rotation of coordinate numerical calculation pattern, preserve the rotation parameter that per step calculates;

(2) realize that with rotation of coordinate numerical calculation pattern Cartesian coordinate is to polar conversion; Based on given multi-transceiver combination signal; After calculating the said given multi-transceiver combination signal of input, the amplitude of the input sample signal that after the rotation of rotation of coordinate numerical calculation pattern, obtains and rotation gain;

(3) product with the gain of the rotation in the amplitude that obtains in the step (1) and threshold value and the step (2) compares:

If the amplitude that obtains in the step (1) is not more than the product of the rotation gain in threshold value and the step (2), then the hard-limiting signal is input multi-transceiver combination signal;

Otherwise, be that initial value is carried out the despining of rotation of coordinate numerical calculation pattern with the ratio and 0 of the gain of the rotation in threshold value and the step (2), wherein, the ratio and 0 of the rotation gain in said threshold value and the step (2) is respectively parameter x ₀With parameter y ₀Initial value, With

Be the multi-transceiver combination signal; And the rotation parameter of preserving during according to rotation of coordinate numerical calculation mode computation calculates the hard-limiting signal, and wherein the rotation parameter of every grade of use of rotation of coordinate numerical calculation pattern despining must align with rotation of coordinate numerical calculation pattern;

Step 2, multi-transceiver combination signal after postponing and hard-limiting signal subtraction are produced the peak value offset signal;

Step 3, estimate the power of each carrier wave, and give the matched filter processing module according to the multicarrier baseband signal;

Step 4, said matched filter processing module are carried out matched filter processing to multicarrier peak value offset signal;

Step 5, the multi-transceiver combination signal summation with filtered peak value offset signal and after postponing add up and obtain the multi-carrier peak-clipping signal.

7. the method for reduction multi-carrier signal peak equal ratio as claimed in claim 6 is characterized in that, further comprises:

The multi-transceiver combination signal is carried out multistage peak clipping iterative processing.

8. like the method for claim 6 or 7 described reduction multi-carrier signal peak equal ratios, it is characterized in that said step 4 further comprises:

(1) with the negative frequency of each carrier wave respective frequencies the peak value offset signal is carried out down-conversion and obtain corresponding baseband signal;

(2) each roadbed band signal is carried out filtering and falls sampling processing;

(3) according to the gain of carrier power estimated value adjusting tunable filter, tunable filter carries out adjustable Filtering Processing to each the roadbed band signal after carrying out filtering and falling sampling processing;

(4) signal after the tunable filter processing is carried out liter a sampling and a Filtering Processing;

(5) with the corresponding frequency of each carrier wave the output signal that rises sampling and Filtering Processing is carried out up-conversion;

(6) summation of the output after each road up-conversion adds up and obtains filtered multicarrier peak value offset signal.

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