CN107483379A - One kind is for TDD ofdm systems optimization robot scaling equipment and method - Google Patents
One kind is for TDD ofdm systems optimization robot scaling equipment and method Download PDFInfo
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- CN107483379A CN107483379A CN201710519235.5A CN201710519235A CN107483379A CN 107483379 A CN107483379 A CN 107483379A CN 201710519235 A CN201710519235 A CN 201710519235A CN 107483379 A CN107483379 A CN 107483379A
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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
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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
- H04L27/2602—Signal structure
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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
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Abstract
The present invention relates to one kind for TDD ofdm systems optimization robot scaling equipment and method, it is characterised in that including：Setup module is pinpointed, initial amplitude setting is carried out for the I roads to receiving and Q roads signal；Pilot tone inserts module, for being compressed processing, the signal after output squeezing processing to the signal set by the fixed point setup module；Scaling module, target amplitude setting is carried out for inserting the signal after module compression is handled to the pilot tone, generates and exports echo signal；Peak-clipping module, the target amplitude of echo signal and target peak-to-average force ratio PAR for being exported according to the scaling module determine peak clipping thresholding, and the echo signal exported according to the peak clipping thresholding to the scaling module carries out same-phase cut processing.Pilot tone inserts the compression processing that module is by way of repetition bits data phase rotates and/or the mode of repetition bits data aggregate scrambling and descrambling is to signal in the robot scaling equipment of the present invention, to reduce PAR.
Description
Technical field
The present invention relates to TDD-OFDM system descendings field, more particularly to a kind of calibrated for TDD-OFDM system optimizations to fill
Put and method.
Background technology
OFDM (Orthogonal Frequency Division Multiplexing) is orthogonal frequency division multiplexi, real
OFDM is MCM (Multi Carrier Modulation) on border, one kind of multi-carrier modulation.OFDM general principle is by height
The data flow of speed is decomposed into N number of parallel low rate data streams, is transmitted simultaneously on N number of subcarrier.These are on N subcarriers
The data symbol of simultaneous transmission, an OFDM symbol is formed, as shown in Figure 1.OFDM symbol both can use the method for time domain to produce
It is raw, the method for frequency domain can also be used to produce.Wherein, the OFDM symbol production method of time domain is also known as Conceptual OFDM
Symbol production method, Conceptual OFDM symbols production method is as shown in Fig. 2 wherein, ωnIt is the frequency of n-th of subcarrier
(rad/s), 1/TuIt is qam symbol speed.The frequency spectrum of subcarrier is spacedly distributed, i.e., subcarrier spacing is constant, fixed
Justice is as follows：
And the OFDM symbol production method of time domain can apply to reality, the Practical OFDM symbols that are otherwise known as produce
Method, in actual applications, OFDM symbol can be realized by using IFFT Digital Signal Processing.In base band, Practical
The production method of OFDM symbol is as shown in figure 3, wherein, a (mN+n) represents the data symbol modulated on n-th of subcarrier, and it is held
Continuous time range is mTu<t≤(m+1)Tu.Ofdm system due to multiple subcarriers Signal averaging together, cause the equal power in peak
It is more larger than (PAPR), so as to need the amplifier of more high linearity.
OFDM multicarrier systems employ orthogonal frequency channel, so can be in the situation of balancing technique that need not be complicated
Lower support speed wireless data transfer, and the ability with very strong anti-fading and anti-intersymbol interference (ISI), but ofdm system
Most important shortcoming is that have larger papr (PAR), it directly affect whole system operating cost and
Efficiency.Peak-to-average force ratio problem is a common problem in multi-carrier modulation (MCM).
Sometime, if multiple carrier waves carry out cumulative with same direction, very big peak value will be produced, so as to want
Ask power amplifier that there is the very big range of linearity.Otherwise, when signal peak enters amplifier nonlinearity region, will make
Signal produces distortion, so as to generate the Intermodulation Interference and out-of-band radiation between subcarrier, the orthogonality destroyed between subcarrier, reduces
Systematic function.Obviously, in order to avoid such case, power amplifier should be operated under high-power compensating coefficient, however, this will again
Cause low-down amplification efficiency and the cost of emitter is become very expensive.On the other hand, if OFDM in mobile communications
Using due to mobile terminal, to obtain energy very limited, thus it requires efficient power amplification.Therefore, it is necessary to using certain technology
To reduce the peak-to-average ratio of signal, make the power amplifier efficient operation in emitter, and improve the overall performance of system.
Under normal circumstances, a signal s (t) peak value should be its envelope | s (t) | maximum.Due to signal amplitude
The probability that maximum occurs is very small, with max | s (t) | come definition signal amplitude peak without too big practical significance.One kind is more
It is the method using probability to define method for effective peak value, and a signal s (t) is in probability PcThe peak value that blocks at place is sPAs long as
Have：
Pr[| s (t) | ＜ sP]=Pc (2)
For ofdm signal, its complex base band signal is represented by：
Wherein, TsSymbol lengths, b are used for OFDMn(i) it is the modulation number of n-th of subcarrier in i-th of OFDM symbol
It is believed that breath.In an OFDM symbol time interval, 0≤t≤Ts, formula (3) is changed into：
Signal s (t) power is
The peak-to-average force ratio of ofdm signal is defined as：
Another conventional parameter is the amplitude peak factor (CF, Crest Factor) of ofdm signal, and it is defined as
The ratio between amplitude peak and rms range values of ofdm signal, i.e.,：
It is CM (cubic metric) to have a kind of new parameter again in LTE at present, it is believed that the high peak-to-average power ratio of signal is direct
The efficiency of power amplifier is influenceed, and power amplifier has much relations to the disposal ability of peak value with coordinating item three times, by the processing energy of power amplifier
Power represents that is, back-off power ratio, current document prove that CM more can table than PAR with parameter power de-rating
Levy power de-rating, CM can the more preferably and more accurate efficiency of prediction power amplifier, and PAR and power de-rating pass
System is not but that dB is mapped with dB.Here is CM definition：
HereReferred to as raw CM,It is WCDMA system
In the raw CM, K of reference speech signal be empirical value, value is 1.85 in a wcdma system, and in multi-carrier systems
Need to redefine, Motorola thinks that value is 1.56 at present.
PAR reduces algorithm research and is broadly divided into two aspects, i.e., for up DFT-S-OFDM systems and downlink OFDMA system
System considers respectively.Discuss that more PAR reduces algorithm both for OFDM in many OFDM books and IEEE paper at present
, it is broadly divided into three classes：Amplitude limit class algorithm, coding class algorithm and probability class algorithm, have per class method the respective starting point and
Characteristic, but this defect all be present per class method.Amplitude limit class technology directly carries out nonlinear operation to the peak value of signal, and it is most straight
Connect, most simply.But because it employs nonlinear operation, therefore in-band noise and out-of-band interference can be brought, so as to reduce system
Performance of BER and spectrum efficiency.Coding class technology using coding by original information code word be mapped to one have compare
In the transmission code collection of good PAR characteristics, so as to avoid the code word that signal peak occurs in those.Such technology is linear mistake
Journey, it will not make signal produce distortion, therefore also not have the shortcomings that amplitude limit class technology.But the calculating of coding class technology is complicated
Degree is very high, and encoding and decoding are all cumbersome.Importantly, the information rate of this kind of technology reduces very fast, therefore only fit
The situation fewer for sub-carrier number.For probability class technology, it avoids the peak value of signal unlike encoding class technology completely,
But being conceived to the probability for making great efforts signal peak occur reduces.The method that such technology uses is also for linear process, therefore, it
Distortion will not be produced to signal.This kind of technology be capable of it is effectively reduce signal PAR values, it the shortcomings that be also computation complexity
It is too big.At present these algorithms all because this or that the reason for have not been entered into the practical stage, many related improvement in addition are calculated
Method is also all proposed in succession.
Relevant PAR reduces the document of algorithm and few in all previous 3GPP meetings, and be essentially all for up discussion,
This cost for being essentially due to terminal user is limited, and can be made complexity in view of base station power amplification equipment to handle height
PAR, thus to descending PAR reduce algorithm substantially without reference to.In preceding meeting several times, namely multi-upstream access mode is not also complete
Before deciding entirely, each major company reduces algorithm to the PAR of OFDMA up-links and is also discussed, and carrying algorithm mainly has
Limit filtration algorithm, subcarrier reservation algorithm are circulated, SLM algorithms is improved, improves PTS algorithms, wherein to circulate limit filtration calculation
Method and subcarrier retain algorithm and are main flow and are written with TR25.814 that these algorithms can be used for present descending OFDM systems
In system.
In summary, the PAR of TDD-OFDM (time-multiplexed ofdm system) system up-downgoings at present, which is reduced, calculates
Frequency-domain spectrum shaping Algorithm and circulation limit filtration algorithm can be respectively adopted in method, and wherein frequency-domain spectrum shaping function is paid the utmost attention to
Kaiser windows.
PAR algorithms are reduced more than all to be carried out in physical layer, may proceed to lift by the PAR of these signals after DUC
Rise, such as physical layer reduces PAR to 6dBc, by being lifted to 8.5dBc after intermediate frequency interpolation filtering.
Therefore, it is necessary to which a kind of peak-to-average ratio that can reduce signal, makes the power amplifier efficient operation in emitter, and
The overall performance of raising system is directed to TDD-OFDM system optimizations robot scaling equipment and method.
The content of the invention
According to an aspect of the present invention, it is provided by the invention to be directed to TDD-OFDM system optimization robot scaling equipments, including：It is fixed
Point setup module, initial amplitude setting is carried out for the I roads to receiving and Q roads signal；Pilot tone inserts module, for fixed point
Signal set by setup module is compressed processing, the signal after output squeezing processing；Scaling module, for being inserted to pilot tone
Signal after module compression processing carries out target amplitude setting, generates and exports echo signal；Peak-clipping module, for according to calibration
The target amplitude and target peak-to-average force ratio PAR of the echo signal of module output determine peak clipping thresholding, and according to peak clipping thresholding to calibration
The echo signal of module output carries out same-phase cut processing.
Alternatively, pilot tone inserts module by way of repetition bits data phase rotates to set by fixed point setup module
Signal be compressed processing.
Alternatively, pilot tone inserts module by way of repetition bits data aggregate is scrambled and descrambled to pinpointing setup module
Set signal is compressed processing.
Alternatively, robot scaling equipment further comprises：Signal scrambling module, for entering to the signal from channel coding module
Row scrambling is handled, the signal after generation scrambling；Serioparallel exchange module, gone here and there for the signal after being scrambled to signal scrambling module
And change, I roads and Q roads signal after generation conversion；Mapping block is modulated, for the I roads after being changed to serioparallel exchange module and Q
Road signal is mapped, and by the signal output after mapping to pinpointing setup module；IFFT processing modules, for being inserted to pilot tone
Signal after module compression processing carries out IFFT processing, and the signal output after IFFT is handled is to scaling module；Cyclic prefix
Module, the echo signal for being exported to scaling module carries out period expansion, and exports the signal after period expansion；In first
Filtering process module is inserted, for carrying out the first interpolation filtering processing to the signal after cyclic prefix module period expansion, and will
Signal output after the processing of first interpolation filtering is to peak-clipping module；Second interpolation filtering processing module, for same to peak-clipping module
Phase cut processing after signal carry out the second interpolation filtering processing, and by the second interpolation filtering processing after signal transmit to
DAC module.
Alternatively, gain control module is set between the second interpolation filtering processing module and DAC module, for second
Signal after the processing of interpolation filtering processing module carries out gain control, is overflowed to prevent stop signal.
According to another aspect of the present invention, it is provided by the invention to be directed to TDD-OFDM system optimization calibrating methods, including
Following steps：S111, initial amplitude setting is carried out to the I roads received and Q roads signal；S112, after being set to initial amplitude
Signal is compressed processing, the signal after output squeezing processing；S114, the signal after handling compression carry out target amplitude and set
Put, generate and export echo signal；S116, peak clipping thresholding is determined according to the target amplitude of echo signal and target peak-to-average force ratio PAR,
And same-phase cut processing is carried out to echo signal according to peak clipping thresholding.
Alternatively, in step S112, to set by fixed point setup module by way of repetition bits data phase rotates
The signal put is compressed processing.
Alternatively, in step S112, mould is set to fixed point by way of repetition bits data aggregate is scrambled and descrambled
Signal set by block is compressed processing.
Alternatively, calibrating method further comprises：S110, carry out initial amplitude on the I roads to receiving and Q roads signal and set
Before putting, scrambling processing is carried out to input signal, serioparallel exchange is carried out to the signal after scrambling, the I roads after conversion and Q roads are believed
Number mapped；S113, before the signal after handling compression carries out target amplitude setting, the signal after handling compression is carried out
IFFT processing；S115, peak clipping thresholding is determined in the target amplitude according to the echo signal and target peak-to-average force ratio PAR, and according to
Before peak clipping thresholding carries out same-phase cut processing to echo signal, period expansion is carried out to echo signal, and to period expansion
Signal afterwards carries out the first interpolation filtering processing；S117, it is true in the target amplitude according to echo signal and target peak-to-average force ratio PAR
Determine peak clipping thresholding, and after carrying out same-phase cut processing to echo signal according to peak clipping thresholding, after the processing of same-phase cut
Signal carry out the second interpolation filtering processing, and by the second interpolation filtering processing after signal transmit to DAC module.
Alternatively, the signal after the processing of the second interpolation filtering is transmitted to before DAC module, and calibrating method further wraps
Include：S118, gain control is carried out to the signal after the processing of the second interpolation filtering, overflowed to prevent stop signal.
The present invention compared with prior art, has advantages below：
1. setup module and scaling module pair are pinpointed by being directed in TDD-OFDM system optimization robot scaling equipments for the present invention
The initial amplitude of signal is set and target amplitude is set, it is ensured that signal will not saturation spilling.
2. the pilot tone insertion module in TDD-OFDM system optimization robot scaling equipments that is directed to of the present invention passes through repetition bits data
The compression processing of the mode of phase place and/or the mode of repetition bits data aggregate scrambling and descrambling to signal, to reduce
PAR；
3. the first interpolation filtering processing module first in TDD-OFDM system optimization robot scaling equipments is directed to by the present invention
Signal output to peak-clipping module, the peak clipping processing of signal after interpolation filtering processing is carried out after the processing of the first interpolation filtering,
So that the signal peak very little of regeneration；
4. the peak-clipping module of the present invention uses same-phase cut processing mode, because amplitude limit is a non-linear process, its
It will cause somewhat to aggravate frequency out-of-band interference, frequency out-of-band interference is bigger, and the interference in frequency band is with regard to smaller, so as to reduce whole system
Performance of BER, amplitude limit post filtering can reduce out of band spectrum interference, also result in signal peak regeneration, although filtering meeting
Cause peak regeneration, but it is more much smaller than the signal peak before amplitude limit, and the peak clipping of signal is handled at the first interpolation filtering
Carried out after reason, the peak value very little of regeneration, therefore, clipping algorithm resource consumption of the invention are small, error vector magnitude (EVM) damage
Hinder it is small, on that can receive with outer influence.
Described above is only the general introduction of technical solution of the present invention, in order to better understand the technological means of the present invention,
And can be practiced according to the content of specification, and in order to allow above and other objects of the present invention, feature and advantage can
Become apparent, below especially exemplified by the embodiment of the present invention.
Brief description of the drawings
By reading the detailed description of hereafter preferred embodiment, it is various other the advantages of and benefit it is common for this area
Technical staff will be clear understanding.Accompanying drawing is only used for showing the purpose of preferred embodiment, and is not considered as to the present invention
Setting.And in whole accompanying drawing, identical part is denoted by the same reference numerals.In the accompanying drawings：
Fig. 1 is the OFDM symbol figure on time-frequency direction；
Fig. 2 is Conceptual OFDM symbol production method schematic diagrames；
Fig. 3 is Practical OFDM symbol production method schematic diagrames；
Fig. 4 is directed to TDD-OFDM system optimization robot scaling equipments for the embodiment of the present invention；
Fig. 5 is the signal PAR of the distinct symbols of the embodiment of the present invention；
Fig. 6 is the rms amplitude of the signal of the distinct symbols of the embodiment of the present invention；
Fig. 7 is that signal repeats to send the conveying flow figure of R times on RK subcarrier in the embodiment of the present invention；
Fig. 8 is that signal repeats to send R transmitting (scrambling) flow on RK subcarrier in the embodiment of the present invention；
Fig. 9 is that signal repeats to send R reception (descrambling) flow on RK subcarrier in the embodiment of the present invention；
Figure 10 be the embodiment of the present invention peak clipping before and after signal PAR to according to；
Figure 11 is that the peak clipping of the embodiment of the present invention carries out the analogous diagram of peak value lifting after interpolation filtering again afterwards；
Figure 12 is the front and rear bit error rate comparison diagram under different Eb/No of peak clipping of the embodiment of the present invention；
Figure 13 is directed to TDD-OFDM system optimization calibrating methods for the embodiment of the present invention.
Embodiment
The exemplary embodiment of the disclosure is more fully described below with reference to accompanying drawings.Although the disclosure is shown in accompanying drawing
Exemplary embodiment, it being understood, however, that may be realized in various forms the disclosure without should be by embodiments set forth here
It is set.On the contrary, these embodiments are provided to facilitate a more thoroughly understanding of the present invention, and can be by the scope of the present disclosure
Completely it is communicated to those skilled in the art.
Those skilled in the art of the present technique are appreciated that unless expressly stated, singulative " one " used herein, " one
It is individual ", " described " and "the" may also comprise plural form.It is to be further understood that what is used in the specification of the present invention arranges
Diction " comprising " refer to the feature, integer, step, operation, element and/or component be present, but it is not excluded that in the presence of or addition
One or more other features, integer, step, operation, element, component and/or their groups.
Those skilled in the art of the present technique are appreciated that unless otherwise defined, all terms used herein (including technology art
Language and scientific terminology), there is the general understanding identical meaning with the those of ordinary skill in art of the present invention.Should also
Understand, those terms defined in such as general dictionary, it should be understood that have with the context of prior art
The consistent meaning of meaning, and unless by specific definitions, otherwise will not be explained with the implication of idealization or overly formal.
In order to solve, existing TDD-ofdm system peak-to-average ratio is excessive to cause power amplifier to be operated in high-power compensation
Under state, however, this will cause low-down amplification efficiency and the cost of emitter is become the problem of very expensive, this hair again
It is bright to propose a kind of peak-to-average ratio that reduce signal, make the power amplifier efficient operation in emitter, and improve system
Overall performance is directed to TDD-OFDM system optimizations robot scaling equipment and method.
Fig. 4 is directed to TDD-OFDM system optimization robot scaling equipments for the embodiment of the present invention, as shown in figure 4, the present invention provides
Be directed to TDD-OFDM system optimization robot scaling equipments, including：Signal scrambling module, for the signal from channel coding module
Carry out scrambling processing, the signal after generation scrambling；Serioparallel exchange module, carried out for the signal after being scrambled to signal scrambling module
Serioparallel exchange, I roads and Q roads signal after generation conversion；Mapping block is modulated, for the I roads after being changed to serioparallel exchange module
Mapped with Q roads signal, and by the signal output after mapping to pinpointing setup module；Setup module is pinpointed, for receiving
The I roads arrived and Q roads signal carry out initial amplitude setting；Pilot tone inserts module, for the signal set by fixed point setup module
It is compressed processing, the signal after output squeezing processing；Scaling module, for inserting the signal after module compression is handled to pilot tone
Target amplitude setting is carried out, generates and exports echo signal；Cyclic prefix module, for the echo signal exported to scaling module
Period expansion is carried out, and exports the signal after period expansion；First interpolation filtering processing module, for cyclic prefix module
Signal after period expansion carries out the first interpolation filtering processing, and by the signal output after the processing of the first interpolation filtering to peak clipping
Module；Peak-clipping module, target amplitude and target peak-to-average force ratio PAR for the signal after being handled according to the first interpolation filtering determine to cut
Peak thresholding, and same-phase cut processing is carried out to the signal after the processing of the first interpolation filtering according to peak clipping thresholding；Second interpolation is filtered
Ripple processing module, for carrying out the second interpolation filtering processing to the signal after the processing of peak-clipping module same-phase cut, and by second
Signal after interpolation filtering processing is transmitted to DAC module.
Setup module and scaling module are pinpointed to letter by being directed in TDD-OFDM system optimization robot scaling equipments for the present invention
Number initial amplitude set and target amplitude set, it is ensured that signal will not saturation overflow.TDD-OFDM is directed to by the present invention
Compression processing of the pilot tone insertion module to signal in system optimization robot scaling equipment, to reduce PAR.
Robot scaling equipment further comprises：IFFT processing modules, enter for inserting the signal after module compression is handled to pilot tone
Row IFFT processing, and the signal output after IFFT is handled is to scaling module.Signal a (the mN+ of modulation mapping input IFFT modules
0), a (mN+1), a (mN+2) ... a (mN+N-1) carry out initial amplitude setting and arrive IFFTAMP, such as 6226 first.Pass through IFFT
After processing, the average amplitude of N number of time sampling point is still IFFTAMP, wherein, IFFT processing gain is 1.Due to modulation
Scrambled before mapping, the data for inputting IFFT are regarded as a kind of pseudo-random sequence, therefore IFFT handles being averaged for output
Amplitude is essentially identical, the difference is that the PAR of signal is different, as shown in Figure 5.Fig. 6 is the letter of the distinct symbols of the embodiment of the present invention
Number rms amplitude, as shown in fig. 6, RMS (X) between distinct symbols is no better than 6226, calculate the DBFS of now signal,
Effectively transmission digit bitlen=15, DBFS power Ydbfs=20*log10 (RMS (X))/2^bitlen)；Wherein, RMS
(X)=sqrt (mean (abs (X) .^2)), therefore in the present invention, Ydbfs=-14.4DBFS.
Physical layer process enters DUC processing modules after completing, DUC completes interpolation filtering processing.
Carrier_zero=zero_stuff (Seri_TR, 2)；
Pfir_DUC=fix ((conv (carrier_zero, hbpsf1_fix))/2^14)；%HB
Interpolation filtering processing will not impact to the average power of signal.
Pilot tone inserts module by way of repetition bits data phase rotates to the signal set by fixed point setup module
It is compressed processing.Fig. 7 is that signal repeats to send the conveying flow figure of R times on RK subcarrier in the embodiment of the present invention, such as
Shown in Fig. 7, insert in module in pilot tone, if user data needs to repeat to send, such as needed on 3072 (K*R) individual subcarriers
Send K=768 data, R=4 transmission of Data duplication, subcarrier 1:Sent on 768 once, 769:Second is sent on 768*2
It is secondary, the like, in 768*3+1:Sent on 768*4 the R=4 times, send all be multiplied by a phase factor exp each time
(jthe1), exp (jthe2) ... exp (jtheR), PAR raisings caused by sending are repeated for reducing signal.It is same in receiving terminal
Sub-carrier positions be multiplied by conjugate phase factor exp (- jthe1), exp (- jthe2) ... exp (- jtheR) can complete phase
The reverse rotation of the factor.In order to save multiplying, phase factor can be rotated according to PI/2, such as 1, -1,1i, -1i.
Four phases rotated according to PI/2.Due to just repeating to transmit after same K subcarrier of signal isolation, thus same signal every
From subcarrier spacing farther out, can more resist frequency selective fading, be not only suitable for the good channel of channel circumstance, for channel dislike
Bad, the big deep fading's channel advantage of frequency selectivity is more obvious.
Pilot tone inserts module by way of repetition bits data aggregate is scrambled and descrambled to set by fixed point setup module
Signal be compressed processing.Fig. 8 is that signal repeats to send R transmitting (scrambling) on RK subcarrier in the embodiment of the present invention
Flow, as shown in figure 8, Data duplication transmission Scrambling Operation processing is as follows：K original BIT signals send R if necessary to repeat
It is secondary, then K signal is repeated R times after arranging, the K*R unified scrambling of bit joint, now using long scrambler can 0,1
Be randomized, then re-modulation map, carry out IFFT modulation so that the peak-to-average force ratio of signal is reduced.
Fig. 9 is that signal repeats to send R reception (descrambling) flow, such as Fig. 9 on RK subcarrier in the embodiment of the present invention
Shown, it is as follows that Data duplication sends descrambling operation processing：Receiving terminal is an inverse process, and the signal received is changed to by FFT
After frequency domain, modulated signal is recalled by equilibrium solution, then then modulated signal demapping carries out joint descrambling to soft BIT data
Operation.After completing descrambling operation, the signal for repeating to send embodies in receiving terminal, now carries out maximum-ratio combing (MRC), complete
Into the soft bit demodulation process of signal.Wherein, when using QPSK modulation, signal is sent on 2RK subcarrier；Work as use
When BPSK is modulated, signal is sent on RK subcarrier.
In the embodiment as shown, pilot tone insert module by way of repetition bits data phase rotates or repeat ratio
The mode of special data aggregate scrambling and descrambling is compressed processing to signal, it is of course also possible to reference to repetition bits data phase
The mode two ways that the mode of rotation is scrambled and descrambled with repetition bits data aggregate is compressed processing to signal.Therefore,
The present invention's is directed to what pilot tone insertion module in TDD-OFDM system optimization robot scaling equipments was rotated by repetition bits data phase
The compression processing of mode and/or the mode of repetition bits data aggregate scrambling and descrambling to signal, to reduce PAR.
In peak-clipping module, because the probability that larger peak value occurs in ofdm signal is very small, therefore, amplitude limit is a kind of non-
Technology that is often direct and effectively reducing peak-to-average force ratio.When using limiting technology to reduce the PAR values of signal, signal amplitude is once
More than setting thresholding when will just be fallen by limit.Clipping processes are realized by following equation：
Wherein, x is the signal amplitude before amplitude limit, and y is the signal amplitude after amplitude limit.From equation, the signal after amplitude limit
Amplitude will be limited in A.Specifically, Figure 10 be the embodiment of the present invention peak clipping before and after signal PAR to according to such as Figure 10 institutes
Show, peak clipping positive effect.
Amplitude limit is a non-linear process, and it will cause somewhat to aggravate frequency out-of-band interference, and out-of-band interference is bigger, in frequency band
Interference is just smaller, thus the performance of BER to reducing whole system has obvious benefits, and amplitude limit post filtering can reduce band
External spectrum disturbs, and also results in peak regeneration.Although filtering can cause peak regeneration, smaller than the signal peak before amplitude limit to obtain
It is more.And peak clipping processing is carried out after high speed filters DUC, the peak value very little of regeneration.Specifically, Figure 11 is implemented for the present invention
The peak clipping of example carries out the analogous diagram of peak value lifting after interpolation filtering again afterwards, and peak clipping is in 34.56*2=60.12MHZ 2
Carried out after times interpolation, peak clipping to 6.4DB, then only increase 1dBc by four times of interpolated peaks again.
Peak clipping thresholding is determined by following algorithm：
TargetPAR=6.5；
THRvalue=fix (IFFTAMP.*10^ (TargetPAR/20))；%%dB, target PAPR
The PAR cans of signal are to effectively reduced to 6.5DB after peak clipping.
Because, because PAR is reduced, within 7dBC, the surplus of reserved peak value is exported due to physical layer is after peak clipping
14.4DB, therefore be now fixed to after 7dBc.On the premise of stet position, a BIT digit can be cut out from highest order
Afterwards, reserved PAR or 8.4Dbc, so leaving sufficiently large surplus for signal 7dBC after peak clipping.Now, signal becomes
15BIT (including a sign bit).If DAC chip is 12BIT, as long as now falling minimum 3BIT from interception, therefore,
When changing different IBT DAC chip, it is thus only necessary to change last interception position.
DAC_data=fix (cfr_DATA/2^3)；%%%16BIT becomes 12BIT, intercepts minimum 3BIT, cuts simultaneously
Fall highest 1BIT, stet position.
DBFSdac1=20*log10 (sqrt (mean (abs (DAC_data) .^2))/2^11)；%%%%%DAC it
There is 8DB-PAR surplus afterwards, do not spilt over for protection signal and reserved enough surpluses.
Because peak clipping is afterwards because PAR is reduced, within 7dBC, due to the pre- surplus for being left to peak value of physical layer output
It is 14.4DB, so being now fixed to after 7dBc.On the premise of stet position, a BIT position can be cut out from highest order
After number, reserved PAR or 8.4Dbc, so having sufficiently large surplus for signal 7dBC after peak clipping.Now signal becomes 15BIT
(including a sign bit).If DAC is 12BIT, as long as now falling minimum 3BIT from interception.
DAC_data=fix (cfr_DATA/2^3)；%%%16BIT becomes 12BIT, intercepts minimum 3BIT, cuts simultaneously
Fall highest 1BIT, stet position.
DBFSdac1=20*log10 (sqrt (mean (abs (DAC_data) .^2))/2^11)；%%%%%DAC it
There is 8DB-PAR surplus afterwards, do not spilt over for protection signal and reserved enough surpluses.
Figure 12 is that the peak clipping of the embodiment of the present invention is front and rear in different Eb/No (energy per bit divided by noise power spectral density)
Under bit error rate comparison diagram；
In the case of peak clipping 4DBC, bit error rate only loses below 0.3dBc under awgn channel, it is contemplated that peak value quilt
Suppressing 4Dbc, the general power of transmission signal can improve 3.3Db, therefore, overall performance lifting 3DBC.Although peak clipping can bring one
Fixed band outward leakage, but the frequency spectrum revealed is still lower 30dBc than signal power, far out spectrum has HB wave filters and simulation to filter
Ripple device, therefore deterioration of the signal to far out spectrum is smaller.The peak-clipping module of the present invention uses same-phase cut processing mode, due to
Amplitude limit is a non-linear process, and it will cause somewhat to aggravate frequency out-of-band interference, and frequency out-of-band interference is bigger, and the interference in frequency band is just
Smaller, so as to reduce the performance of BER of whole system, amplitude limit post filtering can reduce out of band spectrum interference, but also result in
Signal peak is regenerated, more much smaller than the signal peak before amplitude limit although filtering can cause peak regeneration, and signal is cut
Peak processing is carried out after the processing of the first interpolation filtering, the peak value very little of regeneration, therefore, clipping algorithm resource consumption of the invention
Small, error vector magnitude (EVM) damage is small, on that can receive with outer influence.
In order to prevent the interpolation filtering of rear class from having the risk of peak value spilling, in the second interpolation filtering processing module and DAC
Gain control module is set between module, i.e., increases gain control GC before DAC module is sent to, for being filtered to the second interpolation
Signal after the processing of ripple processing module carries out gain control, is overflowed to prevent stop signal.The most frequently used 4 kinds of GC controls are as follows：20*
Log10 (1-1/2^4)=- 1.12,20*log10 (1-1/2^4)=- 0.56,20*log10 (1-1/2^5)=- 0.27,20*
Log10 (1-1/2^6)=- 0.13, gain control need only to shift operation and signed magnitude arithmetic(al)：
DAC_data=DAC_data-fix (DAC_data* (1/2^5))
Figure 13 is directed to TDD-OFDM system optimization calibrating methods for the embodiment of the present invention, and as shown in figure 13, the present invention carries
What is supplied is directed to TDD-OFDM system optimization calibrating methods, including：S110, scrambling processing is carried out to input signal, after scrambling
Signal carries out serioparallel exchange, and the I roads after conversion and Q roads signal are mapped；S111, the I roads after mapping and Q roads signal are entered
Row initial amplitude is set；S112, the signal after being set to initial amplitude are compressed processing, the signal after output squeezing processing；
S113, the signal after handling compression carry out IFFT processing；S114, target amplitude setting is carried out to the signal after IFFT processing,
Generate and export echo signal；S115, period expansion is carried out to echo signal, and first is carried out to the signal after period expansion
Interpolation filtering processing；S116, the target amplitude and target peak-to-average force ratio PAR of the echo signal after being handled according to the first interpolation filtering are true
Determine peak clipping thresholding, and same-phase cut is carried out to echo signal according to peak clipping thresholding；S117, to the letter after the processing of same-phase cut
Number carry out the second interpolation filtering processing；S118, gain control is carried out to the signal after the processing of the second interpolation filtering, gain is controlled
Signal afterwards is transmitted to DAC module.
Device embodiment described above is only schematical, wherein the unit illustrated as separating component can
To be or may not be physically separate, it can be as the part that unit is shown or may not be physics list
Member, you can with positioned at a place, or can also be distributed on multiple NEs.It can be selected according to the actual needs
In some or all of module realize the purpose of this embodiment scheme.Those of ordinary skill in the art are not paying creativeness
Work in the case of, you can to understand and implement.
Through the above description of the embodiments, those skilled in the art can be understood that each embodiment can
Realized by the mode of software plus required general hardware platform, naturally it is also possible to pass through hardware.Based on such understanding, on
The part that technical scheme substantially in other words contributes to prior art is stated to embody in the form of software product, should
Computer software product can store in a computer-readable storage medium, such as ROM/RAM, magnetic disc, CD, including some fingers
Make to cause a computer equipment (can be personal computer, server, or network equipment etc.) to perform each implementation
Method described in some parts of example or embodiment.
In addition, it will be appreciated by those of skill in the art that although some embodiments in this include institute in other embodiments
Including some features rather than further feature, but the combination of the feature of different embodiments means to be in the scope of the present invention
Within and form different embodiments.For example, in the following claims, embodiment claimed it is any it
One mode can use in any combination.
Finally it should be noted that：The above embodiments are merely illustrative of the technical solutions of the present invention, rather than its limitations；Although
The present invention is described in detail with reference to the foregoing embodiments, it will be understood by those within the art that：It still may be used
To be modified to the technical scheme described in foregoing embodiments, or equivalent substitution is carried out to which part technical characteristic；
And these modification or replace, do not make appropriate technical solution essence depart from various embodiments of the present invention technical scheme spirit and
Scope.
Claims (10)
1. one kind is directed to TDD-OFDM system optimization robot scaling equipments, it is characterised in that including：
Setup module is pinpointed, initial amplitude setting is carried out for the I roads to receiving and Q roads signal；
Pilot tone inserts module, for being compressed processing, output squeezing processing to the signal set by the fixed point setup module
Signal afterwards；
Scaling module, target amplitude setting is carried out for inserting the signal after module compression is handled to the pilot tone, is generated simultaneously defeated
Go out echo signal；
Peak-clipping module, the target amplitude of echo signal and target peak-to-average force ratio PAR for being exported according to the scaling module determine
Peak clipping thresholding, and the echo signal exported according to the peak clipping thresholding to the scaling module carries out same-phase cut processing.
2. according to claim 1 be directed to TDD-OFDM system optimization robot scaling equipments, it is characterised in that the pilot tone insertion
Module is compressed processing by way of repetition bits data phase rotates to the signal set by the fixed point setup module.
3. according to claim 1 be directed to TDD-OFDM system optimization robot scaling equipments, it is characterised in that the pilot tone insertion
Module is pressed the signal set by the fixed point setup module by way of repetition bits data aggregate is scrambled and descrambled
Contracting is handled.
4. according to claim 1 be directed to TDD-OFDM system optimization robot scaling equipments, it is characterised in that the robot scaling equipment
Further comprise：
Signal scrambling module, for carrying out scrambling processing, the signal after generation scrambling to the signal from channel coding module；
Serioparallel exchange module, serioparallel exchange, the I after generation conversion are carried out for the signal after being scrambled to the signal scrambling module
Road and Q roads signal；
Mapping block is modulated, is mapped for the I roads after being changed to the serioparallel exchange module and Q roads signal, and will mapping
Signal output afterwards is to pinpointing setup module；
IFFT processing modules, IFFT processing is carried out for inserting the signal after module compression processing to the pilot tone, and by IFFT
Signal output after processing is to the scaling module；
Cyclic prefix module, the echo signal for being exported to the scaling module carries out period expansion, and exports period expansion
Signal afterwards；
First interpolation filtering processing module, for carrying out the first interpolation to the signal after the cyclic prefix module period expansion
Filtering process, and by the signal output after the processing of the first interpolation filtering to the peak-clipping module；
Second interpolation filtering processing module, for carrying out the second interpolation to the signal after peak-clipping module same-phase cut processing
Filtering process, and the signal after the processing of the second interpolation filtering is transmitted to DAC module.
5. according to claim 4 be directed to TDD-OFDM system optimization robot scaling equipments, it is characterised in that in described second
Insert and gain control module is set between filtering process module and the DAC module, for handling mould to second interpolation filtering
Signal after block processing carries out gain control, to prevent the signal from overflowing.
6. one kind is directed to TDD-OFDM system optimization calibrating methods, it is characterised in that including：
S111, initial amplitude setting is carried out to the I roads received and Q roads signal；
S112, the signal after being set to the initial amplitude are compressed processing, the signal after output squeezing processing；
S114, the signal after handling the compression carry out target amplitude setting, generate and export echo signal；
S116, peak clipping thresholding is determined according to the target amplitude of the echo signal and target peak-to-average force ratio PAR, and according to the peak clipping
Thresholding carries out same-phase cut processing to the echo signal.
7. according to claim 6 be directed to TDD-OFDM system optimization calibrating methods, it is characterised in that in step S112
In, processing is compressed to the signal set by the fixed point setup module by way of repetition bits data phase rotates.
8. according to claim 6 be directed to TDD-OFDM system optimization calibrating methods, it is characterised in that in step S112
In, the signal set by the fixed point setup module is compressed by way of repetition bits data aggregate is scrambled and descrambled
Processing.
9. according to claim 6 be directed to TDD-OFDM system optimization calibrating methods, it is characterised in that the calibrating method
Further comprise：
S110, before the described pair of I received road and Q roads signal carry out initial amplitude setting, input signal is scrambled
Processing, serioparallel exchange is carried out to the signal after scrambling, the I roads after conversion and Q roads signal are mapped；
S113, before the signal after the processing to the compression carries out target amplitude setting, the letter after handling the compression
Number carry out IFFT processing；
S115, peak clipping thresholding is determined in the target amplitude according to the echo signal and target peak-to-average force ratio PAR, and according to institute
Before peak clipping thresholding is stated to echo signal progress same-phase cut processing, period expansion is carried out to the echo signal, and
First interpolation filtering processing is carried out to the signal after period expansion；
S117, peak clipping thresholding is determined in the target amplitude according to the echo signal and target peak-to-average force ratio PAR, and according to institute
After peak clipping thresholding is stated to echo signal progress same-phase cut processing, the signal after same-phase cut processing is entered
The processing of the interpolation filtering of row second, and the signal after the processing of the second interpolation filtering is transmitted to DAC module.
10. according to claim 9 be directed to TDD-OFDM system optimization calibrating methods, it is characterised in that in the second interpolation
Signal after filtering process is transmitted to before DAC module, and the calibrating method further comprises：
S118, gain control is carried out to the signal after the processing of the second interpolation filtering, to prevent the signal from overflowing.
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| CN111435929A (en) * | 2020-01-14 | 2020-07-21 | 珠海市杰理科技股份有限公司 | Peak clipping processing method and device based on RAPP curve compression and OFDM transmitter |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20070232246A1 (en) * | 2006-03-30 | 2007-10-04 | Fujitsu Limited | Transmitter and power amplifying method |
| CN102340471A (en) * | 2010-07-19 | 2012-02-01 | 大唐移动通信设备有限公司 | Signal transmission method, device and system in baseband remote scene |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20070232246A1 (en) * | 2006-03-30 | 2007-10-04 | Fujitsu Limited | Transmitter and power amplifying method |
| CN102340471A (en) * | 2010-07-19 | 2012-02-01 | 大唐移动通信设备有限公司 | Signal transmission method, device and system in baseband remote scene |
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| CN111435929A (en) * | 2020-01-14 | 2020-07-21 | 珠海市杰理科技股份有限公司 | Peak clipping processing method and device based on RAPP curve compression and OFDM transmitter |
| CN111435929B (en) * | 2020-01-14 | 2022-10-21 | 珠海市杰理科技股份有限公司 | Peak clipping processing method and device based on RAPP curve compression and OFDM transmitter |
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