CN102868651A - Novel demodulation method based on frequency domain balancing - Google Patents

Novel demodulation method based on frequency domain balancing Download PDF

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Publication number
CN102868651A
CN102868651A CN2012103777821A CN201210377782A CN102868651A CN 102868651 A CN102868651 A CN 102868651A CN 2012103777821 A CN2012103777821 A CN 2012103777821A CN 201210377782 A CN201210377782 A CN 201210377782A CN 102868651 A CN102868651 A CN 102868651A
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frequency domain
data
point
group
demodulation
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张航
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CETC 54 Research Institute
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CETC 54 Research Institute
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Abstract

The invention discloses a novel demodulation method based on frequency domain balancing and belongs to the technical field of modulation-demodulation in a wireless communication system. The novel demodulation method includes: each received symbol is subjected to multiple sampling, namely upsampling, sampling values are drawn with the interval to be upsample multiple subtracting one, the sampling values are recombined to form a plurality of groups of single-time sampling data, all the groups of data are subjected to fast Fourier transformation (FFT) and frequency domain balancing, and the plurality of groups of balanced data are merged in a frequency domain and then are then transmitted to be demodulated and subjected to de-mapping. The novel demodulation method ahs the advantages that the method is used on a system using frequency domain balancing by aid of the frequency domain balancing characteristic, the symbols are subjected to upsampling, drawn to be divided into groups, balanced and merged, and therefore in the complex multi-path information channel environment, multi-path information channel interference is effectively resisted, and effect of timing offset of a sampling clock is reduced.

Description

A kind of novel demodulation method based on frequency domain equalization
Technical field
The invention belongs to the modulation-demodulation technique field in the wireless communication system, be specially adapted in the high system of broadband wireless communication of transmission rate request, as adopting single-carrier frequency domain equalization system or OFDM (OFDM) system of frequency domain equalization.This novel demodulation method can be at transmission environment under the complicated as more abominable multipath channel, solves the problem such as synchronous, balanced of signal, is fit to the transfer of data under the complex-terrain.Relate to a kind of demodulation method based on frequency domain equalization.
Background technology
Wireless communication field, single-carrier frequency domain equalization system and orthogonal frequency division multiplex OFDM system all adopt the frequency domain equalization mode, the interference that the antagonism multipath channel is brought.This will ask demodulator to solve the problem such as synchronous, balanced of signal under multipath channel.Particularly for single-carrier frequency domain equalization system, can not works fine under multipath channel such as traditional sampling clock timing method, and this is very large on the systematic function impact.Traditional sampling clock timing method major part all is to attempt directly to find out the Best Point of sampling or obtain optimum sampling point by match.But these methods are not very good under abominable multipath channel, when having the time domain equalization algorithm to exist, common practices is with the time domain equalization use that combines with the sampling clock timing algorithm, the information of time domain equalization fed back to regularly process with auxiliary timing, but under frequency domain equalization, these methods just can not be suitable for.
Summary of the invention
The objective of the invention is in order to solve under multipath channel the technical problem based on the demodulation of frequency domain equalization, characteristics by frequency domain equalization, grouping sample value after the sampling of process liter is carried out the balanced method that remerges processing afterwards can be in the situation that the serious effective energy of finishing the extraction signal of multipath, not only finished balanced but also reached sampling clock effect regularly, reduce the impact that the sampling clock deviation causes, reached the purpose of sampling clock timing adjustment with lower complexity.
The present invention is applicable to multipath channel based on the demodulation method of frequency domain equalization for the technical scheme that realizes the goal of the invention employing is, the object of the present invention is achieved like this:
A kind of novel demodulation method based on frequency domain equalization, be used for solving timing and the equalization problem of signal under the complicated multipath channel, it is characterized in that: namely rise sampling by the symbol of each reception is repeatedly sampled, sampled value is subtracted 1 for extracting at the interval by the multiple that rises sampling, be reassembled into the data of many group single-time samplings, every group of data are finished FFT carry out frequency domain equalization afterwards, after the equilibrium multi-group data that obtains is merged in frequency domain, deliver to afterwards demodulation and separate the mapping processing, concrete steps are:
A, the symbol that receives is carried out the M point rise after sampling, the filtering, by finding synchronously the original position of a blocks of data that carries out FFT.Wherein, M is the integer greater than 1, and FFT counts and is that N, N represent to carry out N the receiving symbol that have of FFT, and the sampled point of pending FFT will have M * N point;
B, will carry out FFT M * N sampled point successively interval M-1 point extract combination, rearrange, obtain new M group N point sampling value, the interval of each group neighbouring sample value is M-1, and each sampled value in each group is equivalent to receiving symbol has been carried out the unitary sampling of same position.Like this each group is carried out N point FFT and process, obtain M group N point frequency domain data;
C, the M group N point frequency domain data that obtains in to step B at frequency domain carry out respectively equilibrium, obtain the frequency domain data after M organizes the equilibrium that N orders;
D, the M after equilibrium group N point frequency domain data is merged, obtain the frequency domain data after the merging of N point;
E, the frequency domain equalization data after the N point merged are carried out demodulation;
Finish under the multidiameter fading channel demodulation based on frequency domain equalization.
Wherein, among the step D, the method for merging realizes merging for by M group N point is carried out corresponding N point data addition through the data behind the frequency domain equalization.
Wherein, in single-carrier frequency domain equalization system, demodulation mode is in the step e: the frequency domain equalization data after first the N point being merged are carried out IFFT and are obtained the time domain data that N is ordered, and the signal map method in the corresponding modulating is finished and separated the Mapping implementation demodulation afterwards.
Wherein, in ofdm system, demodulation mode is in the step e: the frequency domain equalization data after the N point is merged are directly carried out the solution mapping processing of signal, finish demodulation at frequency domain.
The invention has the beneficial effects as follows: in the system that uses frequency domain equalization, carry out work by the characteristics of frequency domain equalization, extract again grouping by symbol being risen sampling, carry out merging after the equilibrium, collect signal energy via mode balanced and that merge dexterously, saved the step of sampling clock timing adjustment, effectively resisted the impact of multipath channel, compared the timing algorithm that increases under other multipath channel and can reduce complexity.
The present invention is described in detail below in conjunction with accompanying drawing.
Description of drawings
Fig. 1 is method flow diagram of the present invention.
Fig. 2 is the theory diagram of the merging method among the step D of the present invention.
Embodiment
Referring to Fig. 1 to Fig. 2, be applicable to multipath channel based on the demodulation method of frequency domain equalization:
A, the symbol that receives is carried out the M point rise after sampling, the filtering, by finding synchronously the original position of a blocks of data that carries out FFT.Wherein, M is the integer greater than 1, and FFT counts and is that N, N represent to carry out N the receiving symbol that have of FFT, and the sampled point of pending FFT will have M * N point;
Above-mentioned each symbol is carried out M sampling, the representative value of M gets 8,16 etc., represents each symbol and carries out 8 times, 16 times samplings.The representative value of N gets 256,512,1024 etc., and representing that FFT counts is 256,512,1024.
Get 8, N with M and get 256 for example, receiving symbol is carried out 8 liter sampling, a blocks of data that carries out so FFT will have 2048 points, and it is 8 that each symbol sampler is counted.Can add Cyclic Prefix before the general blocks of data, to avoid crosstalking of interblock data.
B, will carry out FFT M * N sampled point successively interval M-1 point extract combination, rearrange, obtain new M group N point sampling value, the interval of each group neighbouring sample value is M-1, and each sampled value in each group is equivalent to receiving symbol has been carried out the unitary sampling of same position.Like this each group is carried out N point FFT and process, obtain M group N point frequency domain data;
If M gets 8, N and gets 256, with 2048 one blocks of data that rise after the sampling, extract 1 point every 7 points, form 8 groups 256 data.So every group of data are essentially identical in the sampling location of each symbol, 8 groups of sampled values are carried out 256 FFT in order process, and are transformed into frequency domain.
C, the M group N point frequency domain data that obtains in to step B at frequency domain carry out respectively equilibrium, obtain the frequency domain data after M organizes the equilibrium that N orders;
M gets 8, N and gets 256, will obtain at last 8 groups of frequency domain datas after 256 equilibriums.
Frequency domain data after D, the equilibrium carries out the merging of M group N point equalization data, obtains the new frequency domain data of N point;
M gets 8, N and gets 256, will obtain 256 frequency domain datas after the merging.
E, the frequency domain equalization data after the N point merged are carried out demodulation;
The frequency domain equalization data that the N point is new can be used as the frequency domain equalization data of making the sampling clock timing adjustment and carry out subsequent demodulation.
The effect of step D of the present invention is the merging of finishing M group N point equalization data.Fig. 2 is the enforcement theory diagram of step D of the present invention, and a kind of mode that comparatively effectively merges has been described.It by first group of equalization data module 1, second group of equalization data module 2 ... until the data module Q after M group equalization data module M, summation module P, the weighting forms.Basic principle is that the equalization data that 1 to M group N is ordered is weighted by summation module Q, obtains the new data of N point.
Method of the present invention in the specific implementation concise and to the point operation principle is as follows:
1. rise sampling process
The frequency that the symbol that receives is adopted M sample value according to each symbol is sampled, establish symbol and be
X then obtains X 1, X 2... X M
2. extraction process successively
After the FFT starting point is windowed regularly, the data point of sampling is taken out N point by the quantity sampling of interval M-1 point, form 1 group of data, obtain so altogether M group data.
3.FFT and balancing procedure
Order enters the FFT module that N order and processes, the line frequency territory equilibrium of going forward side by side.After equilibrium was finished, frequency domain data was owing to the time difference that sampling causes will eliminate.Obtain M group data and be respectively (Y 11, Y 12... Y 1N) ... (Y M1, Y M2... Y MN).
4.M group data merging process
M is organized the N point value addition of the data after the equilibrium, obtain one group of new N point data.Sampled point data devious are after equilibrium, and energy is lowered, and deviation is larger, and energy is reduced more accordingly, and are less to the contribution after the weighting.
( Z 1 = Σ m = 1 M Y m 1 , Z 2 = Σ m = 1 M Y m 2 , ... Z N = Σ m = 1 M Y mN )
5. subsequent demodulation process
N point data after weighting merges in single-carrier frequency domain equalization system, are carried out the IFFT conversion and are returned time domain and process.In ofdm system, then can directly carry out demodulation at frequency domain.
The present invention carries out work by the characteristics of frequency domain equalization in the system that uses frequency domain equalization, extract grouping by symbol being risen sampling again, carries out merging after the equilibrium, and the interference that has effectively resisted multipath channel has reduced the impact of sampling clock timing slip.

Claims (4)

1. novel demodulation method based on frequency domain equalization, be used for solving timing and the equalization problem of signal under the complicated multipath channel, it is characterized in that: namely rise sampling by the symbol of each reception is repeatedly sampled, sampled value is subtracted 1 for extracting at the interval by the multiple that rises sampling, be reassembled into the data of many group single-time samplings, every group of data are finished FFT carry out frequency domain equalization afterwards, after the equilibrium multi-group data that obtains is merged in frequency domain, deliver to afterwards demodulation and separate the mapping processing, concrete steps are:
A, the symbol that receives is carried out the M point rise after sampling, the filtering, by finding synchronously the original position of a blocks of data that carries out FFT; Wherein, M is the integer greater than 1, and FFT counts and is that N, N represent to carry out N the receiving symbol that have of FFT, and the sampled point of pending FFT will have M * N point;
B, will carry out FFT M * N sampled point successively interval M-1 point extract combination, rearrange, obtain new M group N point sampling value, the interval of each group neighbouring sample value is M-1, and each sampled value in each group is equivalent to receiving symbol has been carried out the unitary sampling of same position; Like this each group is carried out N point FFT and process, obtain M group N point frequency domain data;
C, the M group N point frequency domain data that obtains in to step B at frequency domain carry out respectively equilibrium, obtain the frequency domain data after M organizes the equilibrium that N orders;
D, the M after equilibrium group N point frequency domain data is merged, obtain the frequency domain data after the merging of N point;
E, the frequency domain equalization data after the N point merged are carried out demodulation;
Finish under the multidiameter fading channel demodulation based on frequency domain equalization.
2. a kind of novel demodulation method based on frequency domain equalization according to claim 1, its feature
Be: among the step D, the method for merging realizes merging for by M group N point is carried out corresponding N point data addition through the data behind the frequency domain equalization.
3. a kind of novel demodulation method based on frequency domain equalization according to claim 1, it is characterized in that: in single-carrier frequency domain equalization system, demodulation mode is in the step e: the frequency domain equalization data after first the N point being merged are carried out IFFT and are obtained the time domain data that N is ordered, and the signal map method in the corresponding modulating is finished and separated the Mapping implementation demodulation afterwards.
4. a kind of novel demodulation method based on frequency domain equalization according to claim 1, it is characterized in that: in ofdm system, demodulation mode is in the step e: the frequency domain equalization data after the N point is merged are directly carried out the solution mapping processing of signal, finish demodulation at frequency domain.
CN2012103777821A 2012-10-08 2012-10-08 Novel demodulation method based on frequency domain balancing Pending CN102868651A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103457888A (en) * 2013-08-30 2013-12-18 深圳清华大学研究院 Method and device for sending communication signals of unite upsampling and digital forming
CN104660533A (en) * 2015-01-28 2015-05-27 曹明伟 Double-sideband modulation system as well as signal reception end, frequency domain balancing device and method thereof
CN104753832A (en) * 2013-12-27 2015-07-01 联芯科技有限公司 Secondary synchronization signal (SSS) detection method and device
WO2016107236A1 (en) * 2014-12-30 2016-07-07 深圳市中兴微电子技术有限公司 Self-adaptive equalization filtering apparatus and method in optical fibre communications, and storage medium
CN107167771A (en) * 2017-04-28 2017-09-15 深圳市无牙太赫兹科技有限公司 The direct wave suppressing method and system of a kind of microwave imaging system

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103457888A (en) * 2013-08-30 2013-12-18 深圳清华大学研究院 Method and device for sending communication signals of unite upsampling and digital forming
CN103457888B (en) * 2013-08-30 2016-06-08 深圳清华大学研究院 Combine communicate signalling method and the device of liter sampling with digital fabrication
CN104753832A (en) * 2013-12-27 2015-07-01 联芯科技有限公司 Secondary synchronization signal (SSS) detection method and device
CN104753832B (en) * 2013-12-27 2018-03-30 联芯科技有限公司 Auxiliary synchronous signals detection method and device
WO2016107236A1 (en) * 2014-12-30 2016-07-07 深圳市中兴微电子技术有限公司 Self-adaptive equalization filtering apparatus and method in optical fibre communications, and storage medium
CN105812060A (en) * 2014-12-30 2016-07-27 深圳市中兴微电子技术有限公司 Adaptive balanced filter device and method in optical fiber communication
CN105812060B (en) * 2014-12-30 2018-08-03 深圳市中兴微电子技术有限公司 Adaptive equalization filter and method in a kind of fiber optic communication
CN104660533A (en) * 2015-01-28 2015-05-27 曹明伟 Double-sideband modulation system as well as signal reception end, frequency domain balancing device and method thereof
CN104660533B (en) * 2015-01-28 2018-03-02 曹明伟 Double sideband modulation system and its signal receiving end and frequency domain equalization apparatus and method
CN107167771A (en) * 2017-04-28 2017-09-15 深圳市无牙太赫兹科技有限公司 The direct wave suppressing method and system of a kind of microwave imaging system

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Application publication date: 20130109