CN106209720A - A kind of crest suppression method for COFDM system - Google Patents
A kind of crest suppression method for COFDM system Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2614—Peak power aspects
- H04L27/2623—Reduction thereof by clipping
Abstract
The present invention relates to a kind of crest suppression method for COFDM system.Including outside input module, amplitude phase generating module, peakvalue's checking and peak value alignment module, offset the calculating of the pulse factor and modified model filtering forming module and summation module, the method offseted by peak value realizes the peak operation that disappears, and is realized the calculating of signal amplitude and phase place by cordic algorithm；Square operation and divide operations is instead of by displacement is cumulative in the case of error is admissible；In terms of wave filter, instead of former single carrier frequency spectrum wave filter with the wave filter that frequency spectrum is consistent with signal bandwidth, be substantially reduced wave filter design complexities, reduce the use of resources of chip；It is analyzed by the principle of peak process that filter coefficient normalization principle and signal are disappeared, with the addition of a pulse amplifying factor, the number of times of iteration can be reduced, and then also reduce the use of resources of chip.
Description
Technical field
The present invention relates to communication technical field, be specifically related to a kind of crest suppression method for COFDM system.
Background technology
One of COFDM system transfers primary disadvantage is that the power PAR launching signal is higher, owing to COFDM modulates
Being to be overlapped in time domain by some sub-carrier signals, if the symbol phase on subcarrier is identical, then time-domain power is up to
The highest.Furthermore in order to ensure that the frequency spectrum of signal does not leaks, transmitter power amplifier must operate at linear zone, if sent out
Penetrate power to may result in the most greatly transmitter power amplifier and be operated in nonlinear area, thus cause signal can distortion, so needing
The peak-to-average force ratio of signal is launched by taking certain peak technology that disappears to reduce.
Summary of the invention
For problems of the prior art, it is an object of the invention to propose a kind of peak that disappears for COFDM system
Method.
Described a kind of crest suppression method for COFDM system, it is characterised in that: include outside input module, amplitude phase
Position generation module, peakvalue's checking and peak value alignment module, offset the pulse factor and calculate and modified model filtering forming module and asking
And module, its peak step that disappears is:
A. outside input module obtains the I/Q two-way input signal of original input data, the most respectively I/Q two-way input letter
Number flow to amplitude phase generating module and summation module；
B. amplitude phase generating module carries out judgement process to I/Q two-way input signal, as I=0 or Q=0, the most directly amplitude and
Corresponding sine value and cosine value all flow to peakvalue's checking and peak value alignment module；Cordic method is otherwise used to obtain I/Q
The amplitude of two-way input signal and phase place, and obtain sine value and the cosine value of correspondence, then amplitude and corresponding sine value
Peakvalue's checking and peak value alignment module is all flowed to cosine value；
C. peakvalue's checking and peak value alignment module compare the amplitude of I/Q input signal with threshold value, it is thus achieved that exceed thresholding
The peak point of value and peak instruction, then all flow to peak value, sine value and cosine value offset arteries and veins after alignment operation
Rush the factor to calculate and modified model filtering forming module, peak instruction is also flowed to offset the pulse factor simultaneously and calculate and change
Enter type filtering forming module；
D. offset the pulse factor calculate and modified model be filtered into peak value that pattern tuber obtains according to step c, threshold value, sine value and
Cosine value obtains the I road offseting the pulse factor and the Q road offseting the pulse factor respectively, then to offset the pulse factor I road and
Offset the Q road of the pulse factor and be filtered forming operation, then the I road offseting the pulse factor after filtering forming operation with offset
The Q road of the pulse factor flows to summation module；
E. summation module deducts the I road of the original input data after delayed process on the I road offseting the pulse factor, it is thus achieved that disappear peak
After I road output valve；The Q road of the original input data after delayed process is deducted the Q road offseting the pulse factor, it is thus achieved that disappear peak
After Q road output valve.
Described a kind of crest suppression method for COFDM system, it is characterised in that: the I/ that described outside input module obtains
The time-domain signal that I/Q two-way that Q two-way input signal is COFDM system to be exported by modulation is discrete.
Described a kind of crest suppression method for COFDM system, it is characterised in that: first by defeated for I/Q two-way in described step b
Enter signal and expand 64 times of amplitudes using cordic method to obtain I/Q two-way input signal again and phase place simultaneously.
Described a kind of crest suppression method for COFDM system, it is characterised in that: described filtering forming operation includes filtering
Device design, filtering molding and amplitude are amplified.
Described a kind of crest suppression method for COFDM system, it is characterised in that: the filtering that the design of described wave filter obtains
The channel width of device is consistent with the signal bandwidth of COFDM system.
Described a kind of crest suppression method for COFDM system, it is characterised in that: in described amplitude amplification process, logical
The value overregulating the pulse amplifying factor amplifies amplitude, and the bit wide of the pulse amplifying factor is set to 3 bits, and its value takes the integer of 0 to 4.
Described a kind of crest suppression method for COFDM system, it is characterised in that: the value of the described pulse amplifying factor is set to
3。
Described a kind of crest suppression method for COFDM system, it is characterised in that: in described step c used by peakvalue's checking
Time by enumerator count from 0 to 31-delay_num time cycle timing, the value of delay_num is not more than 31；
The delay number delay_num signal that peak value alignment operation exports according to peakvalue's checking, makes peak indication signal postpone 31-
Delay_num time cycle, then create one for the high level indicating the position of actual maximum amplitude to indicate.
Described a kind of crest suppression method for COFDM system, it is characterised in that: described threshold value is according to external data
The I/Q two-way input signal peak that the peak-to-average force ratio before peak, the maximum of I/Q two-way input signal amplitude and target need that do not disappears is equal
It is calculated than three data.
The invention has the beneficial effects as follows: the method offseted by peak value realizes the peak operation that disappears, and is realized by cordic algorithm
Signal amplitude and the calculating of phase place；Square operation and division behaviour is instead of by displacement is cumulative in the case of error is admissible
Make；In terms of wave filter, instead of former single carrier frequency spectrum wave filter with the wave filter that frequency spectrum is consistent with signal bandwidth, significantly
Reduce wave filter design complexities, reduce the use of resources of chip；By peak that filter coefficient normalization principle and signal are disappeared
The principle of process is analyzed, and with the addition of a pulse amplifying factor, can reduce the number of times of iteration, and then also reduce resources of chip
Use.
Accompanying drawing explanation
Fig. 1 be COFDM modulation data do not disappear peak peak-to-average force ratio matlab emulation ccdf curve chart；
Fig. 2 is that 1 iteration disappears the ccdf curve chart of the matlab emulation of peak-to-average force ratio behind peak；
Fig. 3 is that 2 iteration disappear the ccdf curve chart of the matlab emulation of peak-to-average force ratio behind peak.
Detailed description of the invention
Below the present invention is elaborated.
The present invention includes outside input module, amplitude phase generating module, peakvalue's checking and peak value alignment module, offsets arteries and veins
Rush the factor to calculate and modified model filtering forming module and summation module, the steps include:
A. outside input module obtains the time-domain signal that I/Q two-way that COFDM system exported by modulation is discrete, then distinguishes
I/Q two-way input signal is flowed to amplitude phase generating module and summation module；
B. amplitude phase generating module carries out judgement process to I/Q two-way input signal, as I=0 or Q=0, the most directly amplitude
Peakvalue's checking and peak value alignment module is all flowed to corresponding sine value and cosine value；Cordic method is otherwise used to obtain I/
The amplitude of Q two-way input signal and phase place, and obtain sine value and the cosine value of correspondence, then amplitude and corresponding sine value
Peakvalue's checking and peak value alignment module is all flowed to cosine value；For the second situation (I and Q is not the most 0), owing to I/Q is defeated
Enter value to have and just have negative, in order to reduce the complexity of design, its all I/Q input values are mapped to first quartile, i.e. the value of I/Q
Just it is all；And in order to meet the requirement of precision in realizing cordic algorithm, in addition it is also necessary to I/Q input value is expanded 64 times simultaneously,
And will be enlarged by the data after 64 times by 6 grades of cordic_stag, the I/ that it is inputted by each of which level the most according to the following formula
Q input value does same process.
If QK-1> 0 item
IK=IK-1+21-K * QK-1 , QK=QK-1-21-K * IK-1,
Wherein, K=1,2,3,4,5,6；
If QK-1≤ 0
IK=IK-1-21-K * QK-1 ,
QK=QK-1+21-K * IK-1,
Wherein, K=1,2,3,4,5,6.
I0And Q0Represent the value after the input value expansion of I/Q two ends respectively；After assuming that initial input value expands 64 times, I0=64,
Q0=64, then due to Q0> 0, first order output I1=128, Q1=0；Then the second level is due to Q1=0, then I2=I1-0.5*Q1=128,Q2=Q1
+0.5*I1=64, then the third level is due to Q2> 0, I3=I2+0.25*Q2=144,Q3=Q2-0.25*I2=32；I afterwards4=148, Q4=
14；I5=148, Q5=5；I6=148。
The I road output valve of cordic_stag the 6th grade be multiplied by a constant 0.607 (wherein 0.607=311/512) again divided by
64 is exactly the approximation of original input signal amplitude, amplitude I the most now exported6* 311/512/64=1.404, then fixed point is defeated
Go out is 1.
Phase place is according to Q0Q1Q2Q3Q4Q56 bits of composition are as the input of look-up table, and look-up table is as follows
Design: 6 bits of input are the angle of correspondence, and are 45 from the 1st grade to the 6th grade of angle corresponding respectivelyo, 26.56o,
14.03o, 7.12o, 3.57o, 1.80o, in 6 bits of input, bit value is 1, and corresponding angle is just, bit value is 0 correspondence
Angle be negative.If input is 110000, the angle value represented is 45o+26.56o-14.03o-7.12o-3.57o-1.80o=
45.04o, correspondence is output as sin45oWith 45o.But owing to the maximum of SIN function and cosine function only has 1, for reality
Border operation needs use fixed point to process, therefore in this designs, sine and cosine value is amplified 2^N-1 times, N=8, i.e. sine value
With 9 bits, (sine value) represents that it has the fixed point output valve of symbol.For sin45o, cos45oThe output valve of look-up table is
sin45o* 255=180, cos45o* 255=180, the fixed point value of other angle is also that same good being then placed in of calculation in advance is searched
In table, the sine value of look-up table output and cosine value be all on the occasion of, therefore need mapping to revert to each quadrant, thus finally determine
Output valve positive and negative.
C. the amplitude that peakvalue's checking and peak value alignment module input I/Q compares with threshold value, it is thus achieved that exceed thresholding
The peak point of value and peak instruction, then all flow to peak value, sine value and cosine value offset arteries and veins after alignment operation
Rush the factor to calculate and modified model filtering forming module, peak instruction is also flowed to offset the pulse factor simultaneously and calculate and change
Enter type filtering forming module.
Threshold value is that the I/Q two-way according to external data does not disappears the peak-to-average force ratio (PAPR) at peak, I/Q two-way input signal amplitude
Maximum max (x) and target need three data of peak-to-average force ratio (PAPR) be calculated.Such as, it is assumed that the PAPR at the peak that do not disappears
Value is equal to A, and the PAPR value that design object needs is equal to B, according to the formula of PAPR:
Disappear before peak:,
Disappear behind peak:,
Can obtain threshold value:
。
When the amplitude using peakvalue's checking and peak value alignment module to obtain compares with the threshold value set, input
Amplitude have two kinds of situations: the first is to merely enter an amplitude more than threshold value every time, and other is both less than threshold value；Second
Plant the amplitude being to input continuously and be both greater than threshold value.
That amplitude more than threshold value for the first situation just exports as peak value, and other amplitude exports not
Become；For situation in second, these are compared by continuously more than amplitudes of threshold value, take maximum amplitude and export as peak value,
Other output is constant.In the second situation, if if coming in too much more than the amplitude of threshold value continuously, can postpone too many,
Still set the number that compares continuously and be no more than maximum detection number, maximum detection number is set to 31, the most each inspection
The time surveying an amplitude is 1 time cycle, so the maximum detection time is 31 time cycles.
In peakvalue's checking, when detected amplitude is more than threshold value, then two signals of output, respectively peak refers to
Show and postpone number (delay_num) signal；When detected amplitude is less than threshold value, the then peak exported instruction and delay
Number (delay_num) signal is 0；Wherein postpone number (delay_num) to represent and be input into peakvalue's checking and peak value alignment module
The time that data are spent when peakvalue's checking, delay_num is not more than 31.
The position of the position of the peak value exported after peakvalue's checking and the maximum amplitude of input is not the most one to one,
Owing to the peak value of output obtains after relatively, therefore the position of the peak value of output has certainly relative to the position of true peak
Certain delay, so needing to carry out peak value and the true peak one_to_one corresponding that peak value alignment makes it export.
In the first situation, peak value needs to compare with an amplitude below just to obtain, therefore postpones an amplitude；The
The peak value taken in situation in two be need gradually compare more than the amplitude of threshold value all these, therefore output peak value with
Real peak compares several amplitudes of delay (often postpone an amplitude and represent one time cycle of delay).
Peak value alignment operation is actually a process postponed, input amplitude and the delay of sine value (cosine value) and defeated
Entering the delay of amplitude and peak instruction, it is delayed for comparing the position of true peak due to output peak, is realizing
In, signal can not move forward, and can only postpone backward.
Delay number (delay_num) signal that peak value alignment operation exports according to peakvalue's checking makes peak indication signal
Postpone 31-delay_num(31 and subtract delay_num) the individual time cycle, i.e. achieve peak instruction and the position of maximum amplitude
Put purpose one to one.The delay operation of peak indication signal can by counters count from 0 to
31-delay_num time cycle timing, then create a high level, and this high level is exactly the peak value position after postponing
Put instruction, be also the position instruction of actual maximum amplitude.
In order to make phase information and output peak value also one_to_one corresponding, therefore sine value (cosine value) also needs after alignment operation
Export again.
D. offset the pulse factor to calculate and modified model is filtered into peak value that pattern tuber obtains, threshold value, sine according to step c
Value and cosine value obtain the I road offseting the pulse factor and the Q road offseting the pulse factor respectively, then to the I offseting the pulse factor
Road and offset the Q road of the pulse factor and be filtered forming operation, then the I road offseting the pulse factor after filtering forming operation and
The Q road offseting the pulse factor flows to summation module.
This module is mainly used in generating and consistent with original signal spectral bandwidth offsets the pulse factor, offsets the meter of the pulse factor
Calculation formula is:
Offset the pulse factor=(peak value-threshold value) * cosine value+j* (peak value-threshold value) * sine value.
First according to peak value, threshold value, sine value and the cosine value of the output of step c, the I road offseting the pulse factor is calculated
With offset the Q road of the pulse factor,
Offset I road=(peak value-threshold value) * cosine value of the pulse factor,
Offset Q road=(peak value-threshold value) * sine value of the pulse factor.
Offset after the pulse factor has calculated and also need to it is filtered forming operation, because offseting pulse factor needs
Carry out cutting down peak operation with the initial data of COFDM system, so needing to make to offset pulse factor bandwidth and COFDM system
The bandwidth of initial data is consistent.
Filtering forming operation mainly includes 3 parts: first is design wave filter, and second is to offseting the pulse factor
Being filtered molding, the 3rd is to be amplified the I/Q two-way after molding processing.
Wave filter designs: have employed follow-on wave filter for filtering molding, offsets in method for traditional peak value
Using former single carrier frequency spectrum wave filter, filter bandwidht is equal to subcarrier bandwidth；For in COFDM system, subcarrier is individual
Number is 2048, if realizing multicarrier by the way of designing former single carrier frequency spectrum wave filter and adding frequency spectrum shift and superposition
Filtering, the consumption for complexity and resource is the biggest, therefore is simplified by wave filter and be designed as and the channel width of COFDM system
Consistent wave filter.Under conditions of performance meets, so have only to design a wave filter and just can complete conventional filter
Displacement overlap-add operation, greatly reduces the complexity of design, decreases the consumption of resources of chip.Filter design method passes through
The fdatool a width of 8M of tool design band in matlab, cut-off frequency is 4M, sample rate be the 64 rank beta values of 36.5M be 3.7
Kaiser window, its coefficient more than 40dbc, is used 14 bit fixed point to be stored in ROM table by wave filter ACPR of its design, with
Just the forming operation after.
Filtering molding: for a some filter forming operation essence be exactly this point with filter coefficient be multiplied and tire out
The process added.After offseting pulse calculating, I/Q two-way is multiplied with filter coefficient, then carries out cumulative behaviour by SUM module
Make, i.e. complete filtering forming operation.In forming process, design 4 ROM tables, for offseting the forming operation of the pulse factor.
Owing to the coefficient of wave filter is 65 (coefficient number=exponent numbers+1), therefore when first offsets the pulse factor in forming process such as
Fruit appearance second again offsets the pulse factor and comes in, and now first will use the 2nd ROM table also in work, and 4 select 1 multichannel choosing
Selecting device priority is ROM1, ROM2, ROM3, ROM4, if i.e. ROM1 does not works, the next one offsets should when the pulse factor is come in
This first uses ROM1 that it is carried out multiplication operations, if 4 ROM all work and come in the most again to offset pulse because of
Son, the most now this offsets the pulse factor and will be rejected.That yes is The more the better for the table of ROM in theory, and ROM table to be abandoned
Offset the pulse factor the fewest, but process and offset the pulse factor owing to often increasing by a road in actual design, then corresponding hard
Part resource is also required to more, thus this design in we have employed 4 ROM tables, i.e. 4 paths process offset pulse because of
Son.
Amplitude is amplified: in order to be cut by peak value near threshold value when being able to make every minor peaks offset and reduce iteration time
Number, the most newly added one is the pulse amplifying factor, the I/Q two offseting the pulse factor after this variable and molding
Road is multiplied, and expands the amplitude of I/Q two-way the most simultaneously.This variable is determined by normalization and the coefficient maximum of filter coefficient,
Design median filter coefficient is normalized to 14 bits, namely coefficient sum is 2^13-1=8191, the maximum of low-pass filter coefficients
It is 1972 after value normalization, therefore for offseting after the pulse factor goes normalization again by wave filter, maximum is also equal to peak value
Deduct 1/4th (1972/8191) of threshold value, therefore after an iteration, peak value is still more than threshold value.Based on this reason,
The bit wide of the pulse amplifying factor is set to 3 bits by us, and its value takes the integer of 0 to 4:
During the pulse amplifying factor=0, correspondence offsets factor I and Q amplitude is constant；
During the pulse amplifying factor=1, correspondence offsets factor I and Q amplitude expands 1 times；
During the pulse amplifying factor=2, correspondence offsets factor I and Q amplitude expands 2 times；
During the pulse amplifying factor=3, correspondence offsets factor I and Q amplitude expands 3 times；
During the pulse amplifying factor=4, correspondence offsets factor I and Q amplitude expands 4 times.
The conventional peak that disappears is all to realize disappearing the effect at peak by increasing the number of times of iteration, and the effect that amplitude is amplified is exactly will
Disappear each time and peak value is all disappeared near threshold value during peak, such that it is able to reduce the number of times of iteration.
After carrying out an iteration process, the value of its pulse amplifying factor is taken 2,3 and 4 respectively, it is thus achieved that PAPR and EVM
The impact of index is shown in Table 1.
Table 1: the value of the different pulse amplifying factors is for the impact of PAPR and EVM index
Although the value of the pulse amplifying factor is that the peak number that disappears when 4 is most as can be seen from Table 1, disappear peak 2.81dB, when value is 3
Disappear peak 2.04dB, and value is the peak 1.30dB that disappears when 2, but value is EVM when 4 has just reached about 5% in an iteration, makes
Its performance signal deteriorates too serious, because while just offset the difference of the pulse factor and peak value when pulse amplifying factor value is 4
Near threshold value, peak value is cut down, but the point on peak value side can because identical with the phase place offseting the pulse factor and
Peak regeneration occur, it is the biggest that regeneration peak amplitude also can become.Although EVM ability 2.42% when pulse amplifying factor value is 2, but
It is that the peak force degree that disappears is inadequate, therefore often the value of pulse amplification factor is set to 3 in reality is tested.
E. summation module deducts the I road of the original input data after delayed process on the I road offseting the pulse factor, it is thus achieved that
Disappear the I road output valve behind peak；The Q road of the original input data after delayed process is deducted the Q road offseting the pulse factor, it is thus achieved that
Disappear the Q road output valve behind peak.
Summation module is mainly used for subtracting each other original input data with offseting the pulse factor, with the mesh at the peak that reaches to disappear
's.Owing to the input and output of above modules have certain delay, so the delay number sum of each module is exactly last
Original I/Q two-way is inputted the delay umber of beats of data by summation module.I/Q two-way initial data after delay disposal subtracts
Remove the multi-carrier data behind the peak that disappears exactly that obtains of the I/Q two-way offseting the pulse factor of correspondence.
Initial data bandwidth after offseting the bandwidth of the pulse factor and postponing is consistent, and offset the pulse factor maximum and
The maximum amplitude of the input data after delay is all one to one, therefore does difference by both and can reach to disappear the purpose at peak.
In reality is tested, the COFDM at the peak that do not disappears modulation data are 9.67dB at bit error rate PAPR under the conditions of 1e-4,
COFDM modulation data do not disappear peak peak-to-average force ratio ccdf curve as shown in Figure 1.The PAPR behind peak that needs to disappear in design requires can disappear
Subtract about 3dB, EVM index less than 8%, by the operation of step a-e, the first time iterative operation at the peak that reaches to disappear.For once changing
Although after instead of, peak value is by the part that disappears, but according to the simply maximum that peakedness ratio in peakvalue's checking relatively takes, also has other
Some are more than threshold value but are less than the amplitude of peak-peak；And for offseting in pulse factor filtering forming module, we adopt
Simply offset the pulse factor to 4 simultaneously and process, if input offset the pulse factor less than filter coefficient
Length range in more than 4, then we also by unnecessary 4 offset the pulse factor to abandoning.Abandon and also imply that do not have
Disappear peak to the peak value of corresponding initial data；Therefore based on from the standpoint of above 2, the effect at the peak that often disappears after an iteration
Fruit be not it is obvious that after an iteration peak-to-average force ratio ccdf curve as in figure 2 it is shown, the PAPR value of EVM index and abatement such as
Shown in table 1；After an iteration peak-to-average force ratio ccdf curve also find out the peak that disappears after PAPR value be 7.63dB, compare not
The PAPR value 9.67 before peak that disappears just has disappeared 2.04dB, and EVM index is 3.62% as seen from Table 1, meets design requirement；But
Peak-to-average force ratio (PAPR) just cuts down 2.03dB, does not meet our design requirement.To this, we are it is generally required to second iteration (repeats
The operation of step a-e), after second iteration, the ccdf curve of peak-to-average force ratio is as it is shown on figure 3, EVM index is as shown in table 2.
Table 2: disappear the impact for PAPR and EVM index of the peak number of times
Multi-carrier data is after second iteration, and PAPR value is compared the 9.67 of the peak that do not disappears and be have dropped 2.86dB, EVM and refer to for 6.81dB
It is designated as 4.85%, therefore meets design requirement.
Claims (9)
1. the crest suppression method for COFDM system, it is characterised in that: include that outside input module, amplitude phase place generate mould
Block, peakvalue's checking and peak value alignment module, offset the pulse factor and calculate and modified model filtering forming module and summation module, its
The peak step that disappears is:
A. outside input module obtains the I/Q two-way input signal of original input data, the most respectively I/Q two-way input letter
Number flow to amplitude phase generating module and summation module；
B. amplitude phase generating module carries out judgement process to I/Q two-way input signal, as I=0 or Q=0, the most directly amplitude and
Corresponding sine value and cosine value all flow to peakvalue's checking and peak value alignment module；Cordic method is otherwise used to obtain I/Q
The amplitude of two-way input signal and phase place, and obtain sine value and the cosine value of correspondence, then amplitude and corresponding sine value
Peakvalue's checking and peak value alignment module is all flowed to cosine value；
C. peakvalue's checking and peak value alignment module compare the amplitude of I/Q input signal with threshold value, it is thus achieved that exceed thresholding
The peak point of value and peak instruction, then all flow to peak value, sine value and cosine value offset arteries and veins after alignment operation
Rush the factor to calculate and modified model filtering forming module, peak instruction is also flowed to offset the pulse factor simultaneously and calculate and change
Enter type filtering forming module；
D. offset the pulse factor calculate and modified model be filtered into peak value that pattern tuber obtains according to step c, threshold value, sine value and
Cosine value obtains the I road offseting the pulse factor and the Q road offseting the pulse factor respectively, then to offset the pulse factor I road and
Offset the Q road of the pulse factor and be filtered forming operation, then the I road offseting the pulse factor after filtering forming operation with offset
The Q road of the pulse factor flows to summation module；
E. summation module deducts the I road of the original input data after delayed process on the I road offseting the pulse factor, it is thus achieved that disappear peak
After I road output valve；The Q road of the original input data after delayed process is deducted the Q road offseting the pulse factor, it is thus achieved that disappear peak
After Q road output valve.
A kind of crest suppression method for COFDM system the most according to claim 1, it is characterised in that: described outside input
The time-domain signal that I/Q two-way that the I/Q two-way input signal that module obtains is COFDM system to be exported by modulation is discrete.
A kind of crest suppression method for COFDM system the most according to claim 1, it is characterised in that: in described step b first
I/Q two-way input signal is expanded simultaneously 64 times of amplitudes using cordic method to obtain I/Q two-way input signal again and phase place.
A kind of crest suppression method for COFDM system the most according to claim 1, it is characterised in that: described filtering molding
Operation includes that wave filter design, filtering molding and amplitude are amplified.
A kind of crest suppression method for COFDM system the most according to claim 4, it is characterised in that: described wave filter sets
The channel width of the wave filter that meter obtains is consistent with the signal bandwidth of COFDM system.
A kind of crest suppression method for COFDM system the most according to claim 4, it is characterised in that: put in described amplitude
During great, amplifying amplitude by the value of the regulation pulse amplifying factor, the bit wide of the pulse amplifying factor is set to 3 bits, and its value takes 0
To the integer of 4.
A kind of crest suppression method for COFDM system the most according to claim 6, it is characterised in that: described pulse amplifying
The value of the factor is set to 3.
A kind of crest suppression method for COFDM system the most according to claim 1, it is characterised in that: peak in described step c
It is worth the time used by detection by enumerator count from 0 to 31-delay_num time cycle timing, delay_num's
Value is not more than 31；The delay number delay_num signal that peak value alignment operation exports according to peakvalue's checking, makes peak instruction letter
Number postpone 31-delay_num time cycle, then create one and be used for indicate the position of actual maximum amplitude to indicate one
High level.
A kind of crest suppression method for COFDM system the most according to claim 1, it is characterised in that: described threshold value root
According to the I/Q two-way input signal of external data do not disappear the peak-to-average force ratio before peak, the maximum of I/Q two-way input signal amplitude and
Three data of peak-to-average force ratio that target needs are calculated.
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| CN201610607421.XA CN106209720B (en) | 2016-07-28 | 2016-07-28 | A kind of crest suppression method for COFDM system |
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| CN112073990A (en) * | 2020-09-09 | 2020-12-11 | 重庆重邮汇测电子技术研究院有限公司 | Method for realizing peak-to-average ratio detection in serial data stream |
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| CN102075484A (en) * | 2011-01-18 | 2011-05-25 | 中兴通讯股份有限公司 | Method and device for reducing peak-to-average power ratio of signal |
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