CN2907089Y - Multi-carrier wave chopping device - Google Patents

Abstract

The utility model relates to a multi-carrier clipping device for reducing multi-carrier peak-to-average-power ratio, which comprises a hard limiting device to perform hard chipping to the multi-carrier combined signal according to the threshold value produced by the threshold generator; a summation and accumulation device for generating peak value to counteract the signal; a matching filter coefficient generator device for generating matching filter coefficient; a matching filtering processing device for performing the matching filtering processing to the peak value counteracting signal; and a summation and accumulation device for mixing the peak value counteracting signal after being filtered and the multi-carrier combined signal.

Description

A kind of multicarrier clipping device

[technical field]

The present invention relates to a kind of communication system, particularly a kind of multicarrier clipping device that reduces the ingoing power amplifier.

[background technology]

As everyone knows, the sender of wireless base station utilizes power amplifier to transmit in the mobile communication system, to compensate the signal attenuation that brings because of propagation distance.Power amplifier has certain range of linearity, and the cost of power amplifier is by the size decision of its linear zone.Signal with high peak-to-average force ratio can reduce the efficient of power amplifier and increase power consumption, and this linearity to power amplifier has proposed very high requirement.For the guaranteed output amplifier is operated in the range of linearity to improve its efficient, therefore require the signal peak-to-average ratio of ingoing power amplifier below certain limit.

In mobile communication system, often use the slicing technology to reduce the signal peak-to-average ratio of ingoing power amplifier, but the unfortunately introducing of slicing technology may bring emitting performances such as distorted signals, out of band spectrum expansion or monkey chatter to a certain degree.Wideband Code Division Multiple Access (WCDMA) is inserted (WCDMA) system, come the distortion level of gauge signal, leak the out of band spectrum degree of expansion of base station transmitter recently with adjacent-channel power with Error Vector Magnitude and Peak Code Domain Error.

Usually the slicing technology is to be divided into base band slicing technology and digital intermediate frequency (DIF) slicing technology two big classes.The outstanding advantage of base band slicing technology is that its base band of handling before the pulse-shaping filter is carried out, and therefore can not bring any out of band spectrum expansion or adjacent-channel power to leak and compare performance.Its shortcoming is that the peak-to-average force ratio behind the clipped signal process DIF multilevel interpolation filter will increase, and makes very undesirable to the rejection of signal peak-to-average ratio.In addition, the base band slicing causes the distortion of signal bigger, shows as Error Vector Magnitude and Peak Code Domain Error emitting performance and descends.Therefore, under the prerequisite that satisfies Error Vector Magnitude and Peak Code Domain Error emitting performance index, base band slicing technology is difficult to make that the signal peak-to-average ratio through after the DIF processing reaches requirement.

DIF slicing technology is carried out the slicing processing after being meant the multilevel interpolation filter of baseband signal through DIF, and DIF slicing technology commonly used has technology such as hard clipping and matched filtering slicing.The advantage of the hard clipping technology of DIF is that hardware realizes comparatively simple, and shortcoming is that it directly carries out DIF hard-limiting slicing and handles and will cause serious out of band spectrum expansion and adjacent-channel power leakage phenomenon.Leak than under the performance index condition if will guarantee to satisfy adjacent-channel power, at this moment, DIF hard clipping technology then is difficult to reach the peak-to-average force ratio performance of expection.

Another kind of DIF slicing technology is a matched filtering slicing technology, and the technology that the patent of invention of Chinese patent application number 03800497.3 is used just belongs to DIF matched filtering slicing technology, and this technology is at multi-carrier signal slicing situation.If only use scaler to adjust matched filter gain, so that leak and the peak-to-average force ratio that obtains expection under the emitting performance condition such as compare meeting the desired Error Vector Magnitude, Peak Code Domain Error and adjacent-channel power.But, when the transmitting power of each carrier wave is inequality, this slicing technology uses identical zoom factor to adjust the matched filter coefficient of each carrier wave, all by this matched filter coefficient, this will make low carrier wave error span vector of transmitted power level and Peak Code Domain Error emitting performance severe exacerbation to the multi-transceiver combination signal through the peak value offset signal behind the hard clipping.Therefore, satisfying systematic error amplitude of the vector, Peak Code Domain Error and adjacent-channel power leakage than under the index request, the peak-to-average force ratio of signal can not achieve satisfactory results behind its slicing.

In addition, this technical scheme is carried out suitable adjustment to its gain when having considered that individual carrier wave matched filter coefficient produces when the designing filter coefficient, to obtain than only using the scaler adjustment more performance that gains.Unfortunately, this technological invention patent not explanation 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, especially how this adjusts each matched filter gain in system realizes.

[summary of the invention]

The object of the present invention is to provide a kind of multicarrier clipping device that reduces the signal peak-to-average ratio of ingoing power amplifier.

Purpose of the present invention is achieved through the following technical solutions: a kind of multicarrier clipping device, be used to reduce the multicarrier peak-to-average force ratio, and described device comprises: the hard-limiting device that the multi-transceiver combination signal is carried out hard clipping according to the threshold value of threshold generator generation; Be used to produce the summation adding up device of peak value offset signal; Be used to produce the matched filter coefficient generating apparatus of matched filter coefficient; The peak value offset signal is carried out the matched filter processing device of matched filter processing; And the summation adding up device that filtered peak value offset signal is mixed with the multi-transceiver combination signal.

Described multicarrier clipping device further comprised according to multi-carrier signal and threshold parameter producing the threshold generator device that is used for the hard-limiting operation before producing the hard-limiting signal.

Described matched filter coefficient generating apparatus further comprises: baseband I Q complex signal is carried out the carrier power estimation unit that power is estimated; The source filter coefficient is carried out the mixer device of frequency modulation process according to the frequency of each carrier wave correspondence; Carry out the gain regulator of amplitude modulation(PAM) according to the carrier power level of estimating each carrier wave matched filter coefficient after to frequency modulation(FM); The summation collecting apparatus that closes the road matched filter coefficient that is used for the multicarrier correspondence.

Described multicarrier clipping device further comprises the device that the multi-transceiver combination signal is postponed, and the multi-transceiver combination signal after wherein postponing mixes with filtered peak value offset signal.

Described multicarrier clipping device further comprises the iteration means of the peak value offset signal being carried out multistage matched filter processing.

The present invention according to the power estimated value of each carrier wave to the adjustment that gains of the matched filter coefficient of corresponding carriers, multi-carrier signal behind the involutory road carries out digital intermediate frequency matched filtering slicing to be handled, and has avoided using the identical match filter gain to bring extra distorted signals phenomenon to the different carrier wave of power.The present invention is under the condition that satisfies same error amplitude of the vector, Peak Code Domain Error and adjacent-channel power leakage ratio, can obtain better slicing effect, get final product so that the multi-transceiver combination signal behind the slicing has lower peak-to-average force ratio, thereby improved the efficient of power amplifier.

The present invention can carry out suitable modification and cutting according to hardware resource and the performance requirement in the practical communication system design.Such as, during Digital IF Processing,, consider the saving of hardware resource again if when obtaining higher sampling rate, can use the two-stage semi-band filter.If satisfying Error Vector Magnitude, Peak Code Domain Error and adjacent-channel power leakage, wish to obtain lower peak-to-average force ratio performance, can suitably use multistage matched filter 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 realizes in the actual hardware system.

[description of drawings]

Fig. 1 is the schematic diagram of multi-carrier signal generation device and multicarrier peak value clipping device present position among the present invention;

Fig. 2 is the basic block diagram that the multicarrier clipping device in the multi-carrier communications systems is realized among the present invention;

Fig. 3 is a kind of concrete structure figure that realizes multicarrier clipping device basic structure shown in Figure 2;

Fig. 4 is the amplitude-frequency response of matched filter coefficient corresponding among the concrete structure figure shown in Figure 3;

Fig. 5 is an another kind of specific implementation structure chart of realizing multicarrier clipping device basic structure shown in Figure 2.

[embodiment]

The present invention can be explained and be understood completely by the detailed description with the accompanying drawing that provides below, and it is more obvious that feature of the present invention, character and advantage will become.

In the transmitting set of wireless communication system, use slicing technology reduces the multi-carrier signal peak equal ratio of ingoing power amplifier, with efficient that improves power amplifier and the cost that reduces power amplifier.

Please refer to Fig. 1.This figure is the schematic diagram of multi-carrier signal generation device 300 and multicarrier clipping device 400 present positions among the present invention.Multi-carrier signal is formed by stacking by the MF Multi-Channel Per Carrier signal, and for every road single-carrier signal, its production process all is identical, so only explain with the production process of one tunnel single-carrier signal wherein.To every road single-carrier signal, its baseband complex signal is carried out molding filtration by pulse-shaping interpolation filter (PSF) 11, through the employing speed of semi-band filter (HBF) 12 with raising DIF signal, the mirror image of signal in frequency domain suppressed to strengthen by stacked integration dressing interpolation filter (CIC) 13 again, and carry out mixing with digital controlled oscillator (NCO) 14, to form the output of single carrier digital medium-frequency signal.At last, each road single carrier digital medium-frequency signal merges in summer 40 to produce the multi-transceiver combination output signal.Further, if need obtain higher sampling rate and reduce the hardware implementation complexity, can use two-stage semi-band filter (HBF) in Digital IF Processing.

Please refer to Fig. 2.This figure is according to a kind of basic structure that is used to reduce the multicarrier clipping device 400 of multi-carrier signal peak equal ratio of the present invention.As shown in Figure 2, multicarrier clipping device 400 comprises a threshold generator 110, hard-limiting module 120, two Postponement modules 130, matched filter coefficient generator 160, matched filter processing module 150 and two summation accumulator module 140 and 180.Threshold generator 110 is used for the threshold value of hard-limiting according to pre-set threshold parameter and input multi-transceiver combination calculated signals.Hard-limiting module 120 is carried out the hard-limiting processing according to threshold value to input multi-transceiver combination signal, to produce the hard-limiting signal.At this moment, deduct the hard-limiting signal, to produce the peak value offset signal through the multi-transceiver combination signal behind the Postponement module 130.150 each carrier frequency matched filter coefficients of correspondence that produce according to the matched filter generator of matched filter processing module close the road signal, and the peak value offset signal is carried out matched filter processing to obtain filtered peak value offset signal.At last, the former multi-transceiver combination signal through Postponement module 130 deducts filtered peak value offset signal to produce the multicarrier clipped signal.

Multicarrier clipping device 400 of the present invention not only can be applicable to multi-carrier communications systems, also can be applicable to carrier wave communication system.Further below by this device application in multi-carrier communications systems, technical scheme of the present invention is further elaborated.

Please refer to Fig. 3.This figure is the specific implementation structure chart that a kind of three carrier wave slicings of multicarrier clipping device 400 basic structures shown in Figure 2 are handled, and has further described the specific implementation structure chart of matched filtering coefficient generator 160 among Fig. 3.Matched filter coefficient generating apparatus 160 further comprises among Fig. 3: baseband I Q complex signal is carried out the carrier power estimation unit 161 that power is estimated; The source filter coefficient is carried out the mixer device 163,165,167 of frequency modulation process according to the frequency of three carrier wave correspondences; Carry out the gain regulator 168,169,172 of amplitude modulation(PAM) according to the three carrier wave matched filter coefficients of the carrier power level of estimating after to frequency modulation(FM); The summation collecting apparatus 174 that closes the road matched filter coefficient that is used for three carrier wave correspondences.

At first consider the Mathematical Modeling of three carrier communication systems, enter three carrier waves before the three carrier wave slicing modules and close the road complex signal and can be modeled as:

$y\left(k\right)=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}{A}_i\left(k\right)\·e^{(2\mathrm{\π}{f}_{i}k+{\mathrm{\φ}}_i)}$ Formula 1

In the formula 1, A _i(k), f _iAnd φ _iDo complex envelope, NCO frequency and the phase deviation of corresponding i the carrier wave DIF output signal sampling of decibel.

Threshold generator 110 closes the linear threshold linear_thr of road signal y (k) and threshold parameter thr (dB value) generation hard-limiting according to input three carrier waves.Hard-limiting module 120 is again according to linear threshold, and to the signal clip (k) after carrying out the processing of y (k) hard-limiting and obtaining amplitude limit, its processing procedure can be represented with expression:

$\mathrm{clip}\left(k\right)=\left\{\begin{array}{cc}y\left(k\right),& \left|y\left(k\right)\right|\≤\mathrm{linear}\_\mathrm{thr}\\ \mathrm{liner}\_\mathrm{thr}*e^{j*\mathrm{angle}\left(y\left(k\right)\right)},& \left|y\left(k\right)\right|>\mathrm{linear}\_\mathrm{thr}\end{array}\right.$ Formula 2

Three carrier waves after the delay close the road signal to be mixed with signal after the hard-limiting, to produce peak value offset signal c (k).

C (k)=y (k)-clip (k) formula 3

Suppose that source filter coefficient h (n) length is N, each source filter coefficient carries out mixing with the NCO of corresponding carrier wave, obtains the matched filter coefficient matched_h (n) of corresponding i carrier frequency.

$\mathrm{matched}\_h\left(n\right)=h\left(n\right)\·e^{(2\mathrm{\π}{f}_{i}k+{\mathrm{\φ}}_i)},n=\mathrm{1,2},......,N$ Formula 4

Carrier power estimation module dip cycle ground carries out power to the baseband signal of each carrier wave to be estimated, obtains power estimated value PE separately _i, and this power is estimated and maximum transmission power P _Max(full power) calculated gain G _i

$G_i={10}^{\frac{{\mathrm{PE}}_i-P_{\max }}{20}}$ Formula 5

Therefore, the matched filter coefficient of corresponding three carrier waves can be expressed as:

$\mathrm{combiner}\_h\left(n\right)=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}{G}_i\·h\left(n\right)\·e^{(2\mathrm{\π}{f}_i+{\mathrm{\φ}}_i)}$

$=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}{10}^{\frac{{\mathrm{PE}}_i-P_{\max }}{20}}\·h\left(n\right)\·e^{(2\mathrm{\π}{f}_{i}k+{\mathrm{\φ}}_i)}$ Formula 6

Please refer to Fig. 4.This figure has provided three carrier waves has been closed the amplitude-frequency response figure that the road signal carries out the matched filter of slicing processing.The power of each carrier wave is carried out normalization, i.e. during full power emission, its power normalization is to 0dB.The matched filter coefficient gain of corresponding each carrier wave then according to the carrier power of estimating with respect to the deviant of full power (5dB, 0dB and-3dB) adjust.Shown in the figure for each carrier wave respectively with-5dB, 0dB and-power (normalized power value) of 3dB is when launching, the amplitude-frequency response of corresponding matched filter coefficient.

At last, close the road signal through the peak value offset signal after the matched filter processing with three carrier waves of delay and mix, and the three carrier wave clipped signal z (z) that obtain exporting.

(c (k), combiner_h) formula 7 for z (k)=y (k)-filter

In the following formula 7, the operation that filter () expression peak value offset signal c (k) handles by matched filter combiner_h.

Please refer to Fig. 5.This figure is the specific implementation structure chart that the another kind three carrier wave slicings of the basic structure of multicarrier clipping device 400 shown in Figure 2 are handled.The specific implementation of Fig. 5 and Fig. 3 difference are, can require and the hardware resource situation according to systematic function during system design, the N level iteration filter 150 ' that increase is made up of the matched filter processing module, the peak value offset signal is carried out repeatedly the matched filter processing operation, make and satisfying under systematic error amplitude of the vector, Peak Code Domain Error and adjacent-channel power leak than index condition, obtain more excellent peak-to-average force ratio performance, guarantee that promptly the multicarrier clipped signal has littler peak-to-average force ratio.

The present invention can carry out suitable modification and cutting according to hardware resource and the performance requirement in the practical communication system design.Such as, during Digital IF Processing,, consider the saving of hardware resource again if when obtaining higher sampling rate, can use the two-stage semi-band filter.If satisfying Error Vector Magnitude, Peak Code Domain Error and adjacent-channel power leakage, wish to obtain lower peak-to-average force ratio performance, can suitably use multistage matched filter 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 realizes in the actual hardware system.

Here the present invention is described in detail by specific embodiment, 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 not limited to these examples, or some aspect wherein.Scope of the present invention is elaborated by additional claim.

Claims (5)

1, a kind of multicarrier clipping device is used to reduce the multicarrier peak-to-average force ratio, it is characterized in that: described device comprises: the hard-limiting device that the multi-transceiver combination signal is carried out hard clipping according to the threshold value of threshold generator generation; Be used to produce the summation adding up device of peak value offset signal; Be used to produce the matched filter coefficient generating apparatus of matched filter coefficient; The peak value offset signal is carried out the matched filter processing device of matched filter processing; And the summation adding up device that filtered peak value offset signal is mixed with the multi-transceiver combination signal.

2, multicarrier clipping device as claimed in claim 1 is characterized in that: described multicarrier clipping device further comprised according to multi-carrier signal and threshold parameter producing the threshold generator device that is used for the hard-limiting operation before producing the hard-limiting signal.

3, multicarrier clipping device as claimed in claim 1 is characterized in that: described matched filter coefficient generating apparatus further comprises: baseband I Q complex signal is carried out the carrier power estimation unit that power is estimated; The source filter coefficient is carried out the mixer device of frequency modulation process according to the frequency of each carrier wave correspondence; Carry out the gain regulator of amplitude modulation(PAM) according to the carrier power level of estimating each carrier wave matched filter coefficient after to frequency modulation(FM); The summation collecting apparatus that closes the road matched filter coefficient that is used for the multicarrier correspondence.

4, multicarrier clipping device as claimed in claim 1, it is characterized in that: described multicarrier clipping device further comprises the device that the multi-transceiver combination signal is postponed, and the multi-transceiver combination signal after wherein postponing mixes with filtered peak value offset signal.

5, multicarrier clipping device as claimed in claim 1 is characterized in that: described multicarrier clipping device further comprises the iteration means of the peak value offset signal being carried out multistage matched filter processing.

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