CN103428139B - A kind of method and device suppressing peak-to-average force ratio - Google Patents

Abstract

A kind of method and device suppressing peak-to-average force ratio, the method includes: up-sample data in original frequency domain band and IFFT converts the time domain data after being up-sampled；According to by current CR value calculated time domain limiting threshold, the time domain data after up-sampling is carried out amplitude limiting processing and FFT, obtain the frequency domain data after amplitude limit；Data, out of band data in band in frequency domain data after amplitude limit are adjusted respectively, and update above-mentioned current CR value by the new CR value obtained according to data in the band after adjusting；In band after adjusting, data, out of band data carry out the time domain data after IFFT converts the peak-to-average force ratio that is inhibited after merging.The present invention can calculate applicable time domain limiting threshold the most in real time, and can reduce inband distortion and the out-of-band radiation of signal as far as possible.Further, on the premise of ensureing system EVM index, the peak-to-average force ratio of data is reduced as much as possible.The effect that peak-to-average force ratio is suppressed by the present invention is obvious；Without receiver being done any change；Without transferring any extraneous information.

Description

A kind of method and device suppressing peak-to-average force ratio

Technical field

The present invention relates to digital communication technology field, equal particularly to a kind of method suppressing peak-to-average force ratio and a kind of suppression peak The device of ratio.

Background technology

As a kind of multi-carrier modulation technology, OFDM (Orthogonal Frequency Division Multiplexing, OFDM) have that channel utilization is high, anti-multipath fading ability is strong, system is quick to postponing effect Sensitivity is low and technology realizes the advantages such as with low cost, thus is used widely in various fields, and has become the following 4th One of critical transmissions technology for multimedia mobile communication system.

Compared with single-carrier system, owing to OFDM symbol is by multiple independent sub-carrier signals additions through ovennodulation Becoming, therefore, such composite signal is possible to produce bigger peak power.The peak-to-average force ratio of OFDM symbol (PAPR, Peak-to-average power ratio) it is defined as:

$PAPR\left(dB\right)=10{\log }_{10}\frac{max\left\{\right|x_n{|}^2\}}{E\left\{\right|x_n{|}^2\}}$

Wherein, in above formula, PAPR (dB) represents peak-to-average force ratio, x_nRepresent through IFFT (Inverse Fast Fourier Transform inverse fast Fourier transform) after computing obtained by output signal, i.e.

In the ofdm system having N number of subcarrier, in extreme circumstances, the peak power of signal is typically average power N times, therefore the expression formula of the PAPR of baseband signal can be written as: PAPR=10log₁₀N.Such as: for the TD-LTE system of 10MHz Uniting, it has 600 subcarriers, then the PAPR of its limit is: PAPR=10log₁₀N=10log₁₀600=27.78dB.

Excessive peak-to-average force ratio proposes harsher requirement to power amplifier, the efficiency of power amplifier also can be made to decline simultaneously, but, Cost and the existence of technical problem due to High-power amplifier so that the PAPR problem suppressing ofdm system excessive becomes OFDM system Can system one of the key issue of large-scale application.

The mode of at present ofdm system wide variety of one of which suppression PAPR is margining amplitude technique, tradition margining amplitude technique basic Principle is to preset limiting threshold A₀, the part that signal envelope exceedes thresholding directly eliminates:

${\stackrel{\&OverBar;}{X}}_i=\left\{\begin{array}{cc}{X}_i,& \left|X_i\right|<A_0\\ {\mathrm{Le}}^{j\&angle;X_i},& \left|X_i\right|\&GreaterEqual;A_0\end{array}\right.$

Wherein, X_iIt it is the time domain data of input；It it is the time domain data after time domain amplitude limit.It is to say, it is in input When signal amplitude is less than limiting threshold, signal directly transmits；When input signal amplitude is more than or equal to limiting threshold, keep Signal phase is constant, and amplitude is limited in A₀。

This traditional clipping mode, is a kind of mode suppressing PAPR simply and readily realized, and is possible not only to effectively Control peak-to-average force ratio, and complexity is little, redundancy is low.But, this traditional clipping mode, owing to using fixing limit Width threshold value, and in each different time period, input signal is in constantly conversion, this limiting threshold is without along with input The change of signal and be adaptively adjusted, and then the effect of impact suppression peak-to-average force ratio.And, this simple clipping mode can draw Play inband distortion and the out-of-band radiation of signal, produce the bigger bit error rate.

Summary of the invention

For above-mentioned problems of the prior art, it is an object of the invention to provide a kind of side suppressing peak-to-average force ratio Method, a kind of device suppressing peak-to-average force ratio, it can be in the performance that peak-to-average force ratio suppresses, improves peak-to-average force ratio suppression adaptively While, reduce inband distortion and the out-of-band radiation of signal, so that the bit error rate performance of system is without significantly deteriorating.

For reaching above-mentioned purpose, the present invention by the following technical solutions:

A kind of method suppressing peak-to-average force ratio, including step:

Data in the original frequency domain band of input are up-sampled and IFFT conversion, the time domain data after being up-sampled；

It is calculated time domain limiting threshold, according to this time domain limiting threshold to the time domain number after up-sampling according to current CR value According to carrying out amplitude limiting processing and FFT, obtain the frequency domain data after amplitude limit；

Data, out of band data in band in frequency domain data after amplitude limit are adjusted respectively, and according to the band after adjusting Interior data determine and obtain new CR value, and update above-mentioned current CR value by this new CR value；

In band after adjusting, data, out of band data carry out IFFT conversion after merging, the time domain after the peak-to-average force ratio that is inhibited Data.

A kind of device suppressing peak-to-average force ratio, including: frequency domain up-sampling unit, an IFFT unit, time domain clipping unit, In FFT unit, band external-adjuster unit, band, adjustment unit, the 2nd IFFT unit, the peak that disappears update single than adjustment unit, limiting threshold Unit, buffer unit；

Described frequency domain up-sampling unit, for up-sampling data in the original frequency domain band of input, is up-sampled After frequency domain data；

A described IFFT unit, for up-sampling after frequency domain data carry out IFFT conversion up-sampled after time Numeric field data；

Described time domain clipping unit, for according to described limiting threshold updating block input time domain limiting threshold on adopt Time domain data after sample carries out amplitude limiting processing, obtains the time domain data after amplitude limiting processing；

FFT unit, for the time domain data after amplitude limiting processing is carried out FFT, obtains the frequency domain data after amplitude limit；

Band external-adjuster unit, for being adjusted the out of band data in the frequency domain data after described amplitude limit, is adjusted After out of band data；

Adjustment unit in band, for being adjusted data in the band in the frequency domain data after described amplitude limit, is adjusted After band in data, and according to data in original frequency domain band, adjust after band in data be calculated the EVM in the setting time Value；

2nd IFFT unit, the interior data of band after adjusting, the out of band data after adjustment carry out IFFT change after merging Change, the time domain data after the peak-to-average force ratio that is inhibited；

The peak that disappears, than adjustment unit, obtains new CR value for determining according to the EVM value in the described setting time；

Limiting threshold updating block, exports to time described for being calculated time domain limiting threshold according to described new CR value Territory clipping unit；

Buffer unit, data in the original frequency domain band to the described input of caching.

According to the scheme of the invention described above, it can be calculated new CR value according to data in the band after adjusting, and uses This new CR value as up-to-date update in other words after the current peak that disappears than CR value to be calculated real-time time domain amplitude limit threshold Value, say, that applicable time domain limiting threshold can be calculated the most in real time, such that it is able to equal to peak adaptively Ratio suppresses, and improves the performance of peak-to-average force ratio suppression.Further, the present invention program can reduce inband distortion and the band of signal as far as possible External radiation.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of the embodiment of the method for the suppression peak-to-average force ratio of the present invention；

Fig. 2 is the spectrum mask schematic diagram in one concrete example of the present invention；

Fig. 3 is the flow chart of the embodiment of the method for the suppression peak-to-average force ratio of the present invention；

Fig. 4 is the structure chart of the device embodiment one of the suppression peak-to-average force ratio of the present invention；

Fig. 5 is the structure chart of the device embodiment two of the suppression peak-to-average force ratio of the present invention；

Fig. 6 is the structure chart of the device embodiment three of the suppression peak-to-average force ratio of the present invention.

Detailed description of the invention

Below in conjunction with preferred embodiment therein, the present invention program is described in detail.

Shown in Figure 1, it is the schematic flow sheet of the embodiment of the method for the suppression peak-to-average force ratio of the present invention.As it is shown in figure 1, this Method in embodiment includes step:

Step S101: data in the original frequency domain band of input are up-sampled and IFFT conversion, after being up-sampled Time domain data, enters step S102；

Step S102: be calculated time domain limiting threshold according to current CR (Clipping Ratio, disappear peak ratio) value, according to This time domain limiting threshold carries out amplitude limiting processing and FFT (fast Fourier transform) to the time domain data after up-sampling, obtains Frequency domain data after amplitude limit, enters step S103；

Step S103: data, out of band data in the band in the frequency domain data after amplitude limit are adjusted respectively, and according to tune In band after whole, data determine and obtain new CR value, and by the above-mentioned current CR value of this new CR value renewal, entrance step S104；

Step S104: in the band after adjusting, data, out of band data carry out IFFT conversion after merging, and be inhibited peak-to-average force ratio After time domain data.

According to the scheme in the present embodiment, it can be calculated new CR value according to data in the band after adjusting, and uses This new CR value obtains time domain limiting threshold as the CR value after up-to-date renewal in other words, say, that can be with self adaptation Ground is calculated applicable time domain limiting threshold in real time, such that it is able to suppress peak-to-average force ratio adaptively, improves peak-to-average force ratio The performance of suppression.Further, the scheme in the present embodiment can reduce inband distortion and the out-of-band radiation of signal as far as possible

When in above-mentioned steps S101, in the original frequency domain band to input, data up-sample, can be by presetting again The up-sampling of number, preset multiple here can be any one natural number, the difference arranged due to preset multiple, can make Sampling precision and complexity difference, through actual verification, in the case of preset multiple is 2 or 4 so that on adopt The precision of sample and complexity have an effect compromised so that precision and complexity can meet certain requirement, therefore, Under preferable case, preset multiple can be set to 2 or 4.

Wherein, when above-mentioned steps S102 is calculated time domain limiting threshold, can by use various possible in the way of enter Row calculates, and wherein in a concrete example, following formula can be used to carry out:

$A_0={10}^{\frac{CR}{20}}*\sqrt{P_x}$

In above formula, A₀Representing time domain limiting threshold, CR represents current CR value, P_xRepresent the time domain data after up-sampling Mean power.

Wherein, mean power P of the time domain data after above-mentioned up-sampling_x, can directly according to after above-mentioned up-sampling time Numeric field data is directly calculated.On the other hand, adopt on after the frequency domain data after the up-sampling before FFT, FFT The mean power of the time domain data after sample is consistent, accordingly it is also possible to according to the mean power of the frequency domain data after up-sampling Obtain P_x, or directly calculate according to the mean power of the frequency domain data after up-sampling.On the other hand, frequency domain up-samples it The mean power of the frequency domain data after the mean power of front original input data and frequency domain up-sampling is according to above-mentioned preset multiple Become multiple proportion, say, that in the case of obtaining the mean power of original input data, in conjunction with the multiple of up-sampling, can To calculate the mean power of the frequency domain data after up-sampling, and as it was previously stated, the average merit of frequency domain data after Shang Caiyang Rate and P_xIt is identical, accordingly it is also possible to calculate the time domain after obtaining this up-sampling by the mean power of original input data The mean power of data, concrete calculation does not repeats them here.

When the time domain data after up-sampling being carried out amplitude limiting processing according to the time domain limiting threshold obtained, can use down Formula is carried out:

${\stackrel{\&OverBar;}{X}}_i=\left\{\begin{array}{cc}{X}_i,& \left|X_i\right|<A_0\\ A_0{e}^{j\&angle;X_i},& \left|X_i\right|\&GreaterEqual;A_0\end{array}\right.$

In formula, X_iRepresent the time domain data after up-sampling, A₀For time domain limiting threshold,Represent the time domain after amplitude limiting processing Data.According to above-mentioned amplitude limiting processing mode, it is appreciated that: the amplitude of the time domain data after up-sampling is less than time domain limiting threshold Time, signal directly transmits；When time domain data amplitude after up-sampling is more than or equal to limiting threshold, keep signal phase not Become, and amplitude is limited in A₀。

Time domain data after amplitude limiting processing is carried out the frequency domain data after FFT i.e. can get amplitude limit.After to amplitude limit Frequency domain data in band in data when being adjusted, can by use various possible in the way of be adjusted, one wherein In concrete example, can be according to parameter alpha_iData in band are adjusted, specifically can be shown below:

In formula,Represent data in the band in the frequency domain data before amplitude limiting processing, number in the original frequency domain band i.e. inputted According to,Represent data in the band in the frequency domain data after amplitude limit,Represent data in the band after adjusting, Represent the difference carrying interior data in the frequency domain data after the interior data of the band in the frequency domain data before amplitude limiting processing and amplitude limiting processing, Parameter alpha_iCan be from finite aggregate { α_i, i=1,2 ..., M} chooses, wherein the value of M should be much smaller than carrying the individual of interior data Number, concrete value can determine according to actual needs.Finite aggregate { α_i, i=1,2 ..., each element in M} concrete Value can be adopted and be determined in various manners, can set based on experience value under normal circumstances, according to be specifically actually needed Different can have different value setting means.

When the out of band data in the frequency domain data after amplitude limit is adjusted, can by use various possible in the way of enter Row sum-equal matrix, wherein in a concrete example, can be according to amplitude threshold P_iCome number outside the band in the frequency domain data after amplitude limit According to being adjusted:

${\tilde{x}}_i^{outB}=\left\{\begin{array}{cc}{\stackrel{\&OverBar;}{x}}_i^{outB},& \left|{\stackrel{\&OverBar;}{x}}_i^{outB}\right|<P_i\\ P_i{e}^{j\&angle;{\stackrel{\&OverBar;}{x}}_i^{outB}},& \left|{\stackrel{\&OverBar;}{x}}_i^{outB}\right|\&GreaterEqual;P_i\end{array}\right.$

In above formula,Represent the out of band data in the frequency domain data after amplitude limit,Represent the out of band data after adjusting, P_iRepresent the value carrying spectrum mask corresponding on outer frequency i.

Value P of spectrum mask_iCan be by the calculated concrete data of following formula:

$P_i=\left\{\begin{array}{cc}0& 1/N+N_{gf}<i\&le;1\\ -\frac{P_0}{N_{gf}}(i-1/N-N_{gf})& 1/N<i\&le;1/N+N_{gf}\\ P_0& \left|i\right|\&le;1/N\\ \frac{P_0}{N_{gf}}(i+1/N+N_{gf})& -(1/N+N_{gf})\&le;i<-1/N\\ 0& -1\&le;i<-(1/N+N_{gf})\end{array}\right.$

In above formula, i represents that normalized frequency, | i |≤1/N represent in-band frequency, and 1/N ＜ | i |≤1 represents it is up-sampling After out-of-band frequency, N_gfRepresent the bandwidth of isolation strip, N_gf∈ [0,1-1/N], P₀It it is constant.When Fig. 2 shows band external-adjuster One schematic diagram of used spectrum mask.

After in the band in the frequency domain data after amplitude limit, data are adjusted, determine according to data in the band after adjusting During to new CR value, following manner can be used to carry out:

It is calculated Preset Time according to data in the band after data, adjustment in the band in the frequency data before amplitude limiting processing Interior EVM (Error Vector Magnitude, error vector magnitude) value, then according to this EVM value and current CR value It is calculated new CR value.

Above-mentioned EVM value can use following manner to be calculated:

$EVM\_x=\sqrt{\underset{i}{\&Sigma;}\frac{|x_i^{inB}-{\tilde{x}}_i^{inB}{|}^2}{|x_i^{inB}{|}^2}}$

In formula, EVM_x represents calculated EVM value,Represent number in the band in the frequency domain data before amplitude limiting processing According to, data in the original frequency domain band i.e. inputted,Represent data in the band after adjusting.

When being worth to new CR value according to EVM, following formula can be used to be calculated:

In formula, EVM_Th is EVM threshold value；CR_min、CR_maxAnd CR_stepBeing constant, the size of concrete value can be according to reality Border application needs are set, CR ∈ [CR_min,CR_max], according to above formula, it is appreciated that:

When EVM_x exceedes threshold value EVM_Th, the value of increase CR to (CR+CR_max)/2；

When EVM_x is not less than threshold value EVM_Th, with CR_stepFor step value, progressively reduce the value of CR；

If CR has minimized value CR_min, that the most no longer reduces the value of CR.

As it has been described above, according to adjust after band in data determine obtain new CR value time, be in obtaining Preset Time EVM after, then be calculated new CR value based on EVM value and current CR value, therefore the present invention program can ensure EVM On the premise of index, reduce the peak-to-average force ratio of data as much as possible.

According to the method for the suppression peak-to-average force ratio in above-mentioned the present embodiment, give in a concrete example in Fig. 3 is concrete Schematic flow sheet.

As it is shown on figure 3, in this concrete example, the process of concrete suppression peak-to-average force ratio may is that

First data in the original frequency domain band of input are carried out the up-sampling of N times (recommendation N value 2 or 4), obtain on adopt Frequency domain data after sample, then carries out IFFT conversion to the frequency domain data after this up-sampling, the time domain data after being up-sampled；

According to current CR value, applicationIt is calculated time domain limiting threshold A₀；

According to above-mentioned calculated time domain limiting threshold A₀, use formulaObtain above-mentioned Up-sampling after time domain data carry out amplitude limiting processing, obtain the time domain data after amplitude limiting processing；

The time domain data obtained after above-mentioned amplitude limiting processing is carried out FFT, obtains the frequency domain data after amplitude limit；

Frequency domain data after amplitude limit obtained above is divided into data and out of band data in band, carries out the most respectively carrying interior number According to adjusting and out of band data adjustment；

When carrying out carrying interior data point reuse, following formula can be used to carry out:

When carrying out out of band data and adjusting, formula can be usedCarry out；

Out of band data after being then combined with the interior data of the band after above-mentioned adjustment and adjusting, and carry out FFT, thus To inhibiting the time domain data after peak-to-average force ratio, it is achieved the suppression to peak-to-average force ratio；

On the other hand:

While carrying out carrying interior data point reuse, availableIn the unit of account time EVM value；

After obtaining EVM value, while continuing other steps after execution, formula can be used according to the EVM_x obtainedCR value is updated and adjusts, CR value after renewal, adjustment is applied to determining new time domain limiting threshold A₀, it is achieved time domain limiting threshold A₀Self adaptation more Newly, and be applied to the amplitude limiting processing process of subsequent input signals, it is achieved the suppression of adaptive peak-to-average force ratio.

According to the method for the invention described above, the present invention also provides for a kind of device suppressing peak-to-average force ratio.Hereinafter gather therein Better embodiment illustrates respectively.

Embodiment one

Fig. 4 shows the structural representation of the device embodiment one of the suppression peak-to-average force ratio of the present invention.

As shown in Figure 4, the device of the suppression peak-to-average force ratio in the present embodiment includes: frequency domain up-sampling unit 201, first Adjustment unit 206, second in IFFT unit 202, time domain clipping unit 203, FFT unit 204, band external-adjuster unit 205, band IFFT unit 207, the peak that disappears are than adjustment unit 209, limiting threshold updating block 210, buffer unit 208, and wherein, frequency domain up-samples Unit 201, the input of buffer unit 208 access original frequency domain signal, the outfan and first of frequency domain up-sampling unit 201 The input of IFFT unit 202 connects, an input of the outfan of an IFFT unit 202 and time domain clipping unit 203, The input of limiting threshold updating block 210 connects, another input of time domain clipping unit 203 and limiting threshold updating block The outfan of 210 connects, and the outfan of time domain clipping unit 203 is connected with the input of FFT unit 204, FFT unit 204 Outfan is connected with the input of adjustment unit 206 in band external-adjuster unit 205, band respectively, the output of band external-adjuster unit 205 End is connected with the input of the 2nd IFFT unit 207, and another input of the interior adjustment unit 206 of band is defeated with buffer unit 208 Going out end to connect, in band, the outfan of adjustment unit 206 input, the peak that disappears with the 2nd IFFT unit 207 respectively compares adjustment unit The input of 209 connects, and the peak that disappears connects with another input of limiting threshold updating block 210 than the outfan of adjustment unit 209 Connect.

Wherein, above-mentioned frequency domain up-sampling unit 201, for data in the original frequency domain band of input are up-sampled, Frequency domain data after up-sampling；

An above-mentioned IFFT unit 202, for entering the frequency domain data after the up-sampling of frequency domain up-sampling unit 201 input Row IFFT converts the time domain data after being up-sampled；

Above-mentioned time domain clipping unit 203, for according to the time domain limiting threshold of limiting threshold updating block 210 input to the Time domain data after the up-sampling of one IFFT unit 202 input carries out amplitude limiting processing, obtains the time domain data after amplitude limiting processing；

Above-mentioned FFT unit 204, for carrying out FFT to the time domain data after the amplitude limiting processing of time domain clipping unit 203 input Conversion, obtains the frequency domain data after amplitude limit；

Above-mentioned band external-adjuster unit 205, number outside the band in frequency domain data after the amplitude limit to FFT unit 204 input Out of band data according to being adjusted, after being adjusted；

Adjustment unit 206 in above-mentioned band, in the original frequency domain band according to buffer unit 208 input, data are mono-to FFT In the band in frequency domain data after the amplitude limit of unit 204 input, data are adjusted, and data in the band after being adjusted are additionally operable to root It is calculated the EVM in the setting time according to data in the band after data, adjustment in the original frequency domain band of buffer unit 208 input Value；

Above-mentioned 2nd IFFT unit 207, data, band external-adjuster list in the band after adjustment unit 206 in band is adjusted Out of band data after unit 205 adjustment carries out IFFT conversion after merging, the time domain data after the peak-to-average force ratio that is inhibited；

The above-mentioned peak that disappears than adjustment unit 209, for determine according to the EVM value of adjustment unit 206 input in band obtain new CR value；

Above-mentioned limiting threshold updating block 210, for according to the peak CR value newer than what adjustment unit 209 inputted and that disappear The mean power calculating of the time domain data after the up-sampling of one IFFT unit 202 output obtains time domain limiting threshold and exports to time domain Clipping unit 203；

Above-mentioned buffer unit 208, for caching the original frequency domain data of input.

According to the scheme in the present embodiment, it can be calculated new CR value according to data in the band after adjusting, and uses This new CR value as up-to-date update in other words after the current peak that disappears than CR value to obtain time domain limiting threshold, namely Say, can be adaptively calculated and obtain time domain limiting threshold, such that it is able to adaptively peak-to-average force ratio is suppressed, as much as possible Reduce the peak-to-average force ratio of data.

Above-mentioned frequency domain up-sampling unit 201, to when in the original frequency domain band of input, data up-sample, can be by The up-sampling of preset multiple, preset multiple here can be any one natural number, the difference arranged due to preset multiple, meeting Make precision and the complexity difference of up-sampling, through actual verification, in the case of preset multiple is 2 or 4, can make The precision that must up-sample and complexity have an effect compromised so that precision and complexity can meet certain requirement, Therefore, in the preferred case, preset multiple can be set to 2 or 4.

Above-mentioned limiting threshold updating block 210, when being calculated time domain limiting threshold, can be adopted and count in various manners Obtaining, wherein in a concrete example, limiting threshold updating block can be calculated time domain limiting threshold with following formula:

$A_0={10}^{\frac{CR}{20}}*\sqrt{P_x}$

Wherein, A₀Representing time domain limiting threshold, CR represents current CR value, P_xRepresent the flat of the time domain data after up-sampling All power, mean powers P of the time domain data after above-mentioned up-sampling_x, can be directly according to the time domain data after above-mentioned up-sampling Directly it is calculated.

Time domain clipping unit, when the time domain data after up-sampling is carried out amplitude limiting processing, can be carried out by following formula:

${\stackrel{\&OverBar;}{X}}_i=\left\{\begin{array}{cc}{X}_i,& \left|X_i\right|<A_0\\ A_0{e}^{j\&angle;X_i},& \left|X_i\right|\&GreaterEqual;A_0\end{array}\right.$

In formula, X_iRepresent the time domain data after sampling, A₀For time domain limiting threshold,Represent the time domain number after amplitude limiting processing According to, when i.e. the amplitude of the time domain data after up-sampling is less than time domain limiting threshold, signal directly transmits；After up-sampling time When numeric field data amplitude is more than or equal to limiting threshold, keeps signal phase constant, and amplitude is limited in A₀。

In above-mentioned band, adjustment unit is time in the band in the frequency domain data after amplitude limit, data are adjusted, can be according to ginseng Number α_iData in band are adjusted, specifically can be shown below:

In formula,Represent data in the band in the frequency domain data before amplitude limiting processing, number in the original frequency domain band i.e. inputted According to,Represent data in the band in the frequency domain data after amplitude limit,Represent data in the band after adjusting, Represent the difference carrying interior data in the frequency domain data after the interior data of the band in the frequency domain data before amplitude limiting processing and amplitude limiting processing, Parameter alpha_iCan be from finite aggregate { α_i, i=1,2 ..., M} chooses, wherein the value of M should be much smaller than carrying the individual of interior data Number, concrete value can determine according to actual needs.Finite aggregate { α_i, i=1,2 ..., each element in M} concrete Value can be adopted and be determined in various manners, can set based on experience value under normal circumstances, according to be specifically actually needed Different can have different value setting means.

Above-mentioned band external-adjuster unit when the out of band data in the time domain data after amplitude limiting processing is adjusted, Ke Yigen According to amplitude threshold P_iOut of band data in frequency domain data after amplitude limit is adjusted:

${\tilde{x}}_i^{outB}=\left\{\begin{array}{cc}{\stackrel{\&OverBar;}{x}}_i^{outB},& \left|{\stackrel{\&OverBar;}{x}}_i^{outB}\right|<P_i\\ P_i{e}^{j\&angle;{\stackrel{\&OverBar;}{x}}_i^{outB}},& \left|{\stackrel{\&OverBar;}{x}}_i^{outB}\right|\&GreaterEqual;P_i\end{array}\right.$

In formula,Represent the out of band data in the frequency domain data after amplitude limit,Represent the out of band data after adjusting, P_i Represent the value carrying spectrum mask corresponding on outer frequency i.

Value P for spectrum mask_i, band external-adjuster unit 205 can be by the calculated concrete data of following formula:

$P_i=\left\{\begin{array}{cc}0& 1/N+N_{gf}<i\&le;1\\ -\frac{P_0}{N_{gf}}(i-1/N-N_{gf})& 1/N<i\&le;1/N+N_{gf}\\ P_0& \left|i\right|\&le;1/N\\ \frac{P_0}{N_{gf}}(i+1/N+N_{gf})& -(1/N+N_{gf})\&le;i<-1/N\\ 0& -1\&le;i<-(1/N+N_{gf})\end{array}\right.$

In formula, i represents that normalized frequency, | i |≤1/N represent in-band frequency, after the expression of 1/N ＜ | i |≤1 is up-sampling Out-of-band frequency, N_gfRepresent the bandwidth of isolation strip, N_gf∈ [0,1-1/N], P₀It it is constant.

In band, adjustment unit 206 is when obtaining EVM value, and following formula can be used to be calculated:

$EVM\_x=\sqrt{\underset{i}{\&Sigma;}\frac{|x_i^{inB}-{\tilde{x}}_i^{inB}{|}^2}{|x_i^{inB}{|}^2}}$

In formula, EVM_x represents calculated EVM value,Represent number in the band in the frequency domain data before amplitude limiting processing According to, data in the original frequency domain band i.e. inputted,Represent data in the band after adjusting.

Disappear peak than adjustment unit 209 when being worth to new CR value according to EVM, following formula can be used to be calculated:

In formula, EVM_Th is EVM threshold value；CR_min、CR_maxAnd CR_stepBeing constant, the size of concrete value can be according to reality Border application needs are set, CR ∈ [CR_min,CR_max], according to above formula, it is appreciated that:

When EVM_x exceedes threshold value EVM_Th, the value of increase CR to (CR+CR_max)/2；

When EVM_x is not less than threshold value EVM_Th, with CR_stepFor step value, progressively reduce the value of CR；

If CR has minimized value CR_min, that the most no longer reduces the value of CR.

In a concrete example, above-mentioned implement in the specific works process of device of suppression peak-to-average force ratio can be as Lower described:

Frequency domain up-sampling unit 201 carries out N times (recommending N value 2 or 4) to data in the original frequency domain band of input After up-sampling, an IFFT unit 202 carry out IFFT conversion, the time domain data after being up-sampled；

The time domain limiting threshold A that time domain clipping unit 203 inputs according to limiting threshold updating block 210₀, use formulaTime domain data after the up-sampling of the oneth IFFT unit output is carried out amplitude limiting processing；

FFT unit 204 carries out FFT to the time domain data obtained after time domain clipping unit 203 amplitude limiting processing, is limited Frequency domain data after width；

Then, band external-adjuster unit 205 uses formulaLimit to FFT unit 204 output Out of band data in frequency domain data after width adjusts；

In band, the original frequency domain data of adjustment unit 206 binding cache unit 208 caching, use formulaTo the frequency domain after the amplitude limit of FFT unit 204 output In band in data, data are adjusted；

Out of band data, the interior adjustment unit 206 of band after 2nd IFFT unit 207 assemblage zone external-adjuster unit 205 adjustment are adjusted Data in band after whole, and carry out FFT, the time domain data of the peak-to-average force ratio that has been inhibited, thus realize peak-to-average force ratio is pressed down System；

On the other hand:

In band, adjustment unit 206 is when carrying out carrying interior data point reuse, can utilize simultaneously It is calculated the EVM value of setting time interior (generally may be configured as in the unit interval)；

Disappear peak than adjustment unit 209 according to band in adjustment unit 206 output EVM value, employing formulaOffset peak to be adjusted than CR, To the new peak that disappears than CR value, and the peak that disappears that this is new is exported to limiting threshold updating block than CR value；

Then, the peak that disappears that limiting threshold updating block 210 exports than adjustment unit 209 according to the peak that disappears is than CR value, Yi Ji The mean power of the time domain data after the up-sampling of one IFFT unit output, applicationIt is calculated time domain limit Width threshold value A₀, and this new time domain limiting threshold A that will obtain₀Output is to time domain clipping unit 203, by time domain clipping unit 203 New time domain limiting threshold according to the output of this limiting threshold updating block 210 carries out amplitude limiting processing.

Embodiment two

Fig. 5 shows the structural representation of the device embodiment two of the suppression peak-to-average force ratio of the present invention.

As it is shown in figure 5, the difference of the scheme of the present embodiment two and the scheme in embodiment one essentially consists in, in this reality Execute in example: the input of limiting threshold updating block 210 is not that the outfan with an IFFT unit is connected, but with on frequency domain The outfan of sampling unit 201 connects, and limiting threshold updating block 210 is to be calculated according to the frequency-region signal after up-sampling Time domain limiting threshold.

This is because, after the up-sampling that above-mentioned limiting threshold updating block 210 is applied to when calculating time domain limiting threshold Mean power P of time domain data_x, it is consistent with the mean power essence of the frequency domain data after the up-sampling before FFT, Accordingly it is also possible to the mean power of the time domain data after being up-sampled according to the mean power of the frequency domain data after up-sampling P_x, or directly calculate according to the mean power of the frequency domain data after up-sampling.

Other technologies feature in the present embodiment is identical with above-described embodiment one, does not repeats them here.

Embodiment three

Fig. 6 shows the structural representation of the device embodiment three of the suppression peak-to-average force ratio of the present invention.

As shown in Figure 6, the scheme of the present embodiment three essentially consists in the difference of the scheme in embodiment one, in this reality Execute in example: the input of limiting threshold updating block 210 is not that the outfan with an IFFT unit is connected, but is directly accessed Original input data, limiting threshold updating block 210 is to be calculated time domain limiting threshold according to original input data.

This is because, the frequency domain number after the mean power of the original input data before frequency domain up-sampling and frequency domain up-sampling According to mean power based on up-sampling multiple become multiple proportion, say, that obtaining the mean power of original input data In the case of, in conjunction with the multiple of up-sampling, the mean power of the frequency domain data after up-sampling can be calculated, on the other hand, Mean power P of the time domain data after the mean power of the frequency domain data after up-sampling and up-sampling_xIt is identical, therefore, also Mean power Px of the time domain data after obtaining this up-sampling can be calculated by the mean power of original input data, or Mean power based on original input data is directly calculated time domain limiting threshold, and concrete calculation is the most superfluous at this State.

Other technologies feature in the present embodiment is identical with above-described embodiment one, does not repeats them here.

The method and device of the suppression peak-to-average force ratio of the invention described above, can apply the most in an ofdm system, or also Can apply in other the system needing to suppress peak-to-average force ratio.

Invention described above embodiment, is only the detailed description to presently preferred embodiments of the present invention, not structure Become limiting the scope of the present invention.Any amendment, equivalent made within the spirit and principles in the present invention and changing Enter, within should be included in the claims of the present invention.

Claims (8)

1. the method suppressing peak-to-average force ratio, it is characterised in that include step:

Data in the original frequency domain band of input are up-sampled and IFFT conversion, the time domain data after being up-sampled；

It is calculated time domain limiting threshold according to current CR value, according to this time domain limiting threshold, the time domain data after up-sampling is entered Row amplitude limiting processing and FFT, obtain the frequency domain data after amplitude limit；

Data, out of band data in band in frequency domain data after amplitude limit are adjusted respectively, and according to number in the band after adjusting Obtain new CR value according to determining, and update above-mentioned current CR value by this new CR value；

In band after adjusting, data, out of band data carry out IFFT conversion after merging, the time domain data after the peak-to-average force ratio that is inhibited；

Determine that the mode obtaining new CR value includes according to data in the band after adjusting:

It is calculated in the setting time according to data in the band after data, adjustment in the band in the frequency domain data before amplitude limiting processing EVM value, and it is calculated new CR value according to this EVM value and current CR value；

UseBeing calculated described EVM value, wherein, EVM_x represents described EVM value, Represent data in the band in the frequency domain data before amplitude limiting processing,Represent data in the band after adjusting；

Following formula is used to be worth to new CR value according to EVM:

In formula, EVM_Th is EVM threshold value；CR_min、CR_maxAnd CR_stepIt is constant, CR ∈ [CR_min,CR_max]。

The method of suppression peak-to-average force ratio the most according to claim 1, it is characterised in that:

UseIt is calculated described time domain limiting threshold, wherein, A₀Representing time domain limiting threshold, CR represents and works as Front CR value, P_xRepresent the mean power of the time domain data after up-sampling；

And/or

When data up-sample in the original frequency domain band to input, carry out 2 times or the up-sampling of 4 times；

And/or

UseTime domain data after up-sampling is carried out amplitude limiting processing, wherein, X_iAdopt in expression Time domain data after sample, A₀For time domain limiting threshold,Represent the time domain data after amplitude limiting processing；

And/or

UseTo in the frequency domain data after amplitude limit In band, data are adjusted, whereinRepresent data in the band in the frequency domain data before amplitude limiting processing,Represent amplitude limiting processing After frequency domain data in band in data,Represent data in the band after adjusting,It it is the frequency before amplitude limiting processing The difference of data in the interior data of band in numeric field data and the band in the frequency domain data after amplitude limiting processing；α_iIt is from finite aggregate { α_i,i =1,2 ... M} chooses.

The method of suppression peak-to-average force ratio the most according to claim 1, it is characterised in that use following formula to the frequency domain number after amplitude limit Out of band data according to is adjusted:

${\tilde{x}}_i^{outB}=\left\{\begin{array}{cc}{\stackrel{\&OverBar;}{x}}_i^{outB},& \left|{\stackrel{\&OverBar;}{x}}_i^{outB}\right|<P_i\\ P_i{e}^{j\&angle;{\stackrel{\&OverBar;}{x}}_i^{outB}},& \left|{\stackrel{\&OverBar;}{x}}_i^{outB}\right|\&GreaterEqual;P_i\end{array}\right.$

In formula,Represent the out of band data in the frequency domain data after amplitude limiting processing,Represent the out of band data after adjusting, P_i Represent the value carrying spectrum mask corresponding on outer frequency i.

The method of suppression peak-to-average force ratio the most according to claim 3, it is characterised in that use following formula to calculate and obtain described frequency spectrum Value P of template_i:

$P_i=\left\{\begin{array}{cc}0& 1/N+N_{gf}<i\&le;1\\ -\frac{P_0}{N_{gf}}(i-1/N-N_{gf})& 1/N<i\&le;1/N+N_{gf}\\ P_0& \left|i\right|\&le;1/N\\ \frac{P_0}{N_{gf}}(i+1/N+N_{gf})& -(1/N+N_{gf})\&le;i<-1/N\\ 0& -1\&le;i<-(1/N+N_{gf})\end{array}\right.$

In formula, i represents that normalized frequency, | i |≤1/N represent in-band frequency, and 1/N ＜ | i |≤1 represents it is the band after up-sampling Outer frequency, N_gfRepresent the bandwidth of isolation strip, N_gf∈ [0,1-1/N], P₀It it is constant.

5. the device suppressing peak-to-average force ratio, it is characterised in that including: frequency domain up-sampling unit, an IFFT unit, time domain limit In width unit, FFT unit, band external-adjuster unit, band, adjustment unit, the 2nd IFFT unit, the peak that disappears are than adjustment unit, limiting threshold Updating block, buffer unit；

Described frequency domain up-sampling unit, for up-sampling, after being up-sampled data in the original frequency domain band of input Frequency domain data；

A described IFFT unit, for carrying out the time domain number after IFFT conversion is up-sampled to the frequency domain data after up-sampling According to；

Described time domain clipping unit, after according to the time domain limiting threshold of described limiting threshold updating block input to up-sampling Time domain data carry out amplitude limiting processing, obtain the time domain data after amplitude limiting processing；

FFT unit, for the time domain data after amplitude limiting processing is carried out FFT, obtains the frequency domain data after amplitude limit；

Band external-adjuster unit, for being adjusted the out of band data in the frequency domain data after described amplitude limit, after being adjusted Out of band data；

Adjustment unit in band, for being adjusted, after being adjusted data in the band in the frequency domain data after described amplitude limit Data in band, and the EVM value being calculated in the setting time according to data in the band after data, adjustment in original frequency domain band；

2nd IFFT unit, carries out IFFT conversion after being used for the out of band data merging after the interior data of the band after adjusting, adjustment, Time domain data after suppression peak-to-average force ratio；

The peak that disappears, than adjustment unit, obtains new CR value for determining according to the EVM value in the described setting time；

Limiting threshold updating block, exports limit to described time domain for being calculated time domain limiting threshold according to described new CR value Width unit；

Buffer unit, data in the original frequency domain band caching described input；

In described band, adjustment unit usesIt is calculated described EVM value, wherein, EVM_x table Show described EVM value,Represent data in the band in the frequency domain data before amplitude limiting processing,Represent data in the band after adjusting；

The described peak that disappears uses than adjustment unit

It is worth to new according to EVM CR value, wherein, EVM_Th is EVM threshold value；CR_min、CR_maxAnd CR_stepIt is constant, CR ∈ [CR_min,CR_max]。

The device of suppression peak-to-average force ratio the most according to claim 5, it is characterised in that:

Limiting threshold updating block usesIt is calculated described time domain limiting threshold, wherein, A₀Represent time domain Limiting threshold, CR represents current CR value, P_xRepresent the mean power of the time domain data after up-sampling；

And/or

Frequency domain up-sampling unit to input original frequency domain band in data up-sample time, carry out 2 times or 4 times on adopt Sample；

And/or

Time domain clipping unit usesTime domain data after up-sampling is carried out amplitude limiting processing, its In, X_iRepresent the time domain data after up-sampling, A₀For time domain limiting threshold,Represent the time domain data after amplitude limiting processing；

And/or

In band, adjustment unit usesAfter amplitude limit In band in frequency domain data, data are adjusted, wherein,Represent data in the band in the frequency domain data before amplitude limiting processing, Represent data in the band in the frequency domain data after amplitude limiting processing,Represent data in the band after adjusting,It it is limit The difference of data in band in frequency domain data after data and amplitude limiting processing in band in frequency domain data before treatment；α_iBe from Finite aggregate { α_i, i=1,2 ... M} chooses.

The device of suppression peak-to-average force ratio the most according to claim 5, it is characterised in that band external-adjuster unit uses following formula to limit The out of band data in frequency domain data after width process is adjusted:

${\tilde{x}}_i^{outB}=\left\{\begin{array}{cc}{\stackrel{\&OverBar;}{x}}_i^{outB},& \left|{\stackrel{\&OverBar;}{x}}_i^{outB}\right|<P_i\\ P_i{e}^{j\&angle;{\stackrel{\&OverBar;}{x}}_i^{outB}},& \left|{\stackrel{\&OverBar;}{x}}_i^{outB}\right|\&GreaterEqual;P_i\end{array}\right.$

In formula,Represent the out of band data in the frequency domain data after amplitude limiting processing,Represent the out of band data after adjusting, P_i Represent the value carrying spectrum mask corresponding on outer frequency i.

The device of suppression peak-to-average force ratio the most according to claim 7, it is characterised in that band external-adjuster unit uses following formula to calculate Obtain value P of described spectrum mask_i:

$P_i=\left\{\begin{array}{cc}0& 1/N+N_{gf}<i\&le;1\\ -\frac{P_0}{N_{gf}}(i-1/N-N_{gf})& 1/N<i\&le;1/N+N_{gf}\\ P_0& \left|i\right|\&le;1/N\\ \frac{P_0}{N_{gf}}(i+1/N+N_{gf})& -(1/N+N_{gf})\&le;i<-1/N\\ 0& -1\&le;i<-(1/N+N_{gf})\end{array}\right.$

In formula, i represents that normalized frequency, | i |≤1/N represent in-band frequency, and 1/N ＜ | i |≤1 represents it is the band after up-sampling Outer frequency, N_gfRepresent the bandwidth of isolation strip, N_gf∈ [0,1-1/N], P₀It it is constant.