CN1170443C - Method for measuring motion speed of mobile station in mobile communication - Google Patents
Method for measuring motion speed of mobile station in mobile communication Download PDFInfo
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- CN1170443C CN1170443C CNB011086076A CN01108607A CN1170443C CN 1170443 C CN1170443 C CN 1170443C CN B011086076 A CNB011086076 A CN B011086076A CN 01108607 A CN01108607 A CN 01108607A CN 1170443 C CN1170443 C CN 1170443C
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- frequency
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- doppler
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- travelling carriage
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Abstract
The present invention discloses a method for measuring the moving speed of a mobile station. The method is characterized in that after received signals, namely spatial electromagnetic waves, are processed through antennas, radio frequency and medium frequency, demodulated and(or) de-spread, a power frequency spectrum analysis method, such as an FFT analysis method or a small wave analysis method, is used for analyzing the frequency spectrums of the obtained signals; thus, the frequency difference of the output frequency of a local oscillator of carrier waves transmitted by a transmitter and the output frequency of the local oscillator of a receiver is identified so as to obtain the largest doppler frequency; thus, the moving speed of the mobile station can be calculated. The method can conveniently, rapidly and accurately estimate the moving speed of the mobile station.
Description
Technical field
The present invention is mainly used in moving communicating field, and it is mainly used in moving communicating field.
Background technology
As everyone knows, wireless channel has comprised the multipath transmisstion of electric wave, the time delay expansion, and fading characteristic and Doppler effect, in mobile communication, we will take into full account the scheme of these characteristics and solution.Owing to there be the poor of carrier wave that transmitter launches and receiver local oscillator output frequency, make accurately to measure and move the Doppler frequency that causes by travelling carriage and become difficult.
In the mobile communication, the movement velocity of travelling carriage influences the receptivity of system, if can accurately estimate the movement velocity of travelling carriage, system configuration and performance all can be greatly improved.Simultaneously, along with the arrival in 3G (Third Generation) Moblie epoch, mobile radio communication will have more strong functions, will adopt the structure of more optimizing aspect network layer for this reason, and layered cell structure will become one of core technology of 3G (Third Generation) Moblie.So-called floored community, be exactly that system is in distributing radio resource, take into full account the optimization of entire system, translational speed faster the user assign to bigger macrocell, and slow user assigns to Microcell, speed threshold becomes an important parameter of system, and speed how easy, that measure current mobile station accurately just becomes a urgent problem.
Because the mobility of travelling carriage also has Doppler effect in the mobile communication in the wireless channel.In mobile communication, when travelling carriage is shifted to the base station motion, frequency gets higher, during away from the base station, frequencies go lower.We will take into full account " Doppler effect " in mobile communication.Though, because in the daily life, the limitation of our translational speed, there is no fear of bringing very big frequency shift (FS), but this undeniablely can bring influence to mobile communication, causes our problem in communicating by letter for fear of this influence, our in addition various considerations of having to technically.Also strengthened the complexity of mobile communication.Below we will discuss out the principle and the model of Doppler frequency spectrum.
Doppler frequency shift and motion velocity of mobile station and the travelling carriage direction of motion, relevant with the angle between the radio wave incident direction.If travelling carriage is towards incident wave direction motion, then Doppler frequency shift is just (being the receive frequency rising); If travelling carriage incident wave direction motion dorsad, then Doppler frequency shift is negative (being that receive frequency descends).Signal is propagated through different directions, and its multipath component causes Doppler's diffusion of received signal, thereby has increased signal bandwidth.
Usually each footpath signal is because arrival direction is different with the angle of receiver movement velocity direction, and the Doppler frequency shift in each footpath is also different.According to the channel difference, can set up following operating mobile station model:
(1) for outdoor channel, we think has a large amount of incident multipath signals centering on the obstructed glancing incidence of travelling carriage
Evenly distribute on the angle, the directional diagram of reception antenna also is equally distributed on level angle.For base
Stand, we think that the arrival direction of multipath signal is to be limited within certain level angle scope.For
Outdoor channel, we think have a large amount of incident multipath signals the level angle different around the base station and
Evenly distribute on the vertical angle. can produce CLASSIC spectrum as shown in Figure 2 thus.
(2) for outdoor channel, we think has a large amount of incident multipath signals centering on the different level angle in base station
And evenly distribute on the vertical angle.Can produce the FLAT spectrum of showing as Fig. 3 thus.
(3) for being different from above-mentioned two kinds of characteristics of channel, as long as its doppler spectral is to become block within the specific limits to distribute,
The present invention also is suitable for.In order to study a question conveniently, this paper adopts CLASSIC and FLAT analysis of spectrum problem.
Because Doppler frequency and speed have close getting in touch, so Doppler frequency has great practical value.The Doppler radar that militarily uses for example, sonar, the Doppler positioning technology of in satellite communication, using, and medically also using relevant Doppler frequency technology.By analyzing Doppler frequency is a kind of important velocity estimation mode, about Doppler frequency deviation measure and the patent and the document of velocity estimation a lot, patent WO 01/17185 A1 for example, " estimation of channel variation rate in the Rake receiver ", the thought that this piece patent proposes is, now estimate a class value, then this class value is input in the Doppler frequency estimator, thereby generation is to Doppler's frequency displacement estimated value by a channel estimator.And then by the f that concerns of Doppler frequency and speed
Doppler=(v/ λ) * cos θ estimates mobile station speed.The thinking of this method is and channel combines, and comes the estimating Doppler frequency displacement with the result of channel estimating, obtains Doppler frequency shift and is used further to estimation to mobile station speed.Doppler bandwidth is relevant in the patent US5513221 communication channel for another example estimates, the thought that proposes, relative velocity according to Receiver And Transmitter is adjusted equalizer, this needs one frequency pilot sign is estimated, results estimated is sent into a processor and is carried out Doppler frequency (relative velocity between travelling carriage and the base station) estimation, utilizes this correction channel estimation value as a result then.
These utilize the method for Doppler frequency solution velocity estimation all very complicated.A lot of methods will combine with channel estimating, and channel estimating itself is exactly a very complicated technology.And existing technology all is under the prerequisite that does not overcome the carrier frequency frequency difference, and the research and utilization Doppler effect tests the speed.And in practice, this frequency difference is inevitably, and it is because kinetic Doppler frequency mixes, and has reduced the accuracy that tests the speed from Doppler frequency.Therefore, when adopting Doppler frequency to test the speed, identification carrier frequency frequency difference is very important.
As everyone knows, be baseband signal to be modulated on the very high carrier frequency transmit at the transmitting terminal of communication system, the carrier frequency that produces at receiving terminal transmission signals and the local oscillator realization demodulation of multiplying each other, Here it is the simplest communication process.Because modulated carriers and local frequency inevitably have frequency difference all up to thousands of megahertzes.In the IS-95 standard, the maximum frequency difference that can allow approximately is 200 hertz.Just as preamble is mentioned, in mobile channel, can produce Doppler frequency, the size of this frequency is relevant with speed.For example, the speed of supposing certain travelling carriage is 120 kilometers/hour, and the Doppler frequency difference of Chan Shenging approximately is 220 hertz so.When received signal, more than two kinds of frequency differences mix, make us can not accurately measure Doppler frequency difference.
Summary of the invention
In order better to adapt to the requirement of 3G (Third Generation) Moblie, task of the present invention provides a kind of by overcoming the poor of carrier wave that transmitter launches and receiver local oscillator output frequency, measures Doppler frequency, and then calculates the short-cut method of mobile station speed.
The solution of the present invention is: in spread spectrum communication, information 1 to be passed is taken advantage of spreading code earlier, carries out spread spectrum 2, and spread-spectrum signal is sent modulator 3 to.When modulation signal, to multiply by modulating frequency f1 5, then through RF 6 and transmitting antenna 4 emissions.Send into demodulator 8 demodulation after receiving terminal receives signal, that adopt is the carrier frequency f2 of local oscillator herein.If f1=f2 then be the accurate demodulation under the perfect condition, but this is impossible in practice, both frequency difference Δ f=|f
1-f
2| approximately be about 200 hertz.Signal after the demodulation is sent integration filter 11 to through despreading 10, and the filtering harmonic component keeps baseband signal.Comprised carrier frequency frequency difference and Doppler frequency information in the baseband signal this moment.Our purpose will be done spectrum analysis exactly.According to the knowledge of Digital Signal Processing,, just can obtain the spectrum information of signal flow, as shown in Figure 4 by information flow being fast fourier transform FFT 12.The method of power spectrumanalysis 12 commonly used can be the fast fourier transform analytic approach, also can be wavelet analysis method.
Fig. 5 exists emission carrier wave and reception carrier frequency difference Δ f=|f
1-f
2| situation under modulation spectrum figure.Fig. 5 and local frequency f
2The demodulation of multiplying each other is owing to exist frequency difference Δ f=|f
1-f
2|, can not recover Doppler frequency spectrum in base band, thereby produce four special Frequency points.Can know these four points by inference by demodulation principle is f
d+ Δ f, f
d-Δ f ,-f
d+ Δ f ,-f
d-Δ f, as shown in Figure 6.
Fig. 7 carries out power spectrumanalysis 12 to information flow, and the power spectrum curve of gained, just the base-band signal spectrum figure among Fig. 6 after the filtering high order harmonic component.Because the said carrier frequency frequency difference that exists in front, accurately demodulation is modulated Doppler frequency so be equivalent to frequency difference, thereby has produced the curve of Fig. 7.Analysis 12 to this power curve can utilize existing analytical technology, and for example wavelet analysis method can obtain f
a, f
b,-f
a,-f
b, this frequency values of 4.Determine to carry out frequency computation part 13 after this four dot frequencies value, just can obtain Doppler's peak frequency and carrier frequency frequency difference: f by simple plus and minus calculation
d=(f
a+ f
b)/2, Δ f=(f
a-f
b)/2, wherein f
dBe maximum doppler frequency, corresponding present speed.Produce principle formula V=f according to Doppler frequency
d* λ, the λ carrier wavelength just can have been calculated mobile station speed V very easily.
Produce carrier frequency frequency difference Δ f by frequency computation part 13, can be used for revising local oscillator f
2Frequency, carry out automatic frequency configuration, make f
2Reach one more stable and frequency values is accurately promptly realized the automatic frequency configuration.
Essence of the present invention has provided a kind of method of discriminatory carrier local frequency difference, eliminate the influence of transmitter of mobile communications system tranmitting frequency and receiver local frequency error, by separating the carrier frequency frequency difference, measure Doppler frequency more accurately, and then estimate mobile station speed more accurately.
In sum, we can obtain advantage of the present invention and are:
1. overcome the poor of carrier wave that transmitter launches and receiver local oscillator output frequency, thereby separated the Doppler frequency spectrum relevant with mobile station speed.
2. the present invention has avoided loaded down with trivial details design, has simplified system, has saved hardware cost.
3. the present invention has taken into full account the actual conditions of current communication system, and is realistic, and those skilled in the art just can grasp, and the field has a wide range of applications.
4. the inventive method is reliable, and is easy, can make quickly and accurately mobile station speed is estimated.
Description of drawings
Fig. 1 is the angle schematic diagram between motion velocity of mobile station and the direction of motion and the radio wave incident direction.
Wherein, θ is the angle between the incident wave and the travelling carriage direction of motion, and V is a translational speed, and λ is a carrier wavelength, f
Doppler=(V/ λ) * cos θ is owing to the travelling carriage motion produces Doppler frequency.
Fig. 2 is the CLASSIC spectral pattern
Wherein, f
dIt is maximum doppler frequency.
Fig. 3 is the FLAT spectral pattern
Wherein, f
dIt is maximum doppler frequency.
Fig. 4 is the present invention program's structural representation
Wherein, the 1st, information to be passed, the 2nd, spread spectrum, the 3rd, modulator, the 4th, antenna, the 5th, the modulating frequency f1 in the modulator 3, the 6th, radio-frequency transmissions, the 7th, radio frequency receives, and the 8th, demodulator, the 9th, the carrier frequency f2 of the local oscillator that demodulator 8 adopts, the 10th, despreading, the 11st, integration filter, the 12nd, power spectrum line analysis, the 13rd, frequency computation part, the 14th, mobile station speed is estimated.
Fig. 5 exists emission carrier wave and reception carrier difference Δ f=|f
1-f
2| situation under contain Doppler's modulation spectrum figure.
Wherein, transverse axis coordinate representation the relativeness of each frequency, the curve that can see Fig. 5 is the curve of a shovel type;
Fig. 6 exists emission carrier wave and reception carrier difference Δ f=|f
1-f
2| situation under the Doppler frequency spectrum that contains separate and change the line map.
Wherein, transverse axis coordinate representation the relativeness of each frequency, the curve that can see Fig. 6 is the curve of a shovel type;
Fig. 7 is the power spectrum curve to obtaining after the information flow filtering high order harmonic component
Wherein, f
aBe f
d+ Δ f, f
bBe f
d-Δ f ,-f
bBe-f
d-Δ f ,-f
aBe-f
d+ Δ f.
Fig. 8 is the power spectrum curve analogous diagram of 200 hertz of frequency differences
Fig. 9 is the power spectrum curve analogous diagram of 100 hertz of frequency differences
From Fig. 8, among Fig. 9 as can be seen, this two figure and Utopian Fig. 6, Fig. 7 basically identical.
Embodiment
Below we will build communication system according to above thinking and carry out emulation.When simulation parameter is provided with, we select above-mentioned CLAASIC spectrum to come call for Votes as Doppler's model, and establish the movement velocity V=120 km of current mobile station/hour, propagation velocity of electromagnetic wave C=300000000 meter per second, the transmission carrier frequency is the F=2G hertz, as can be known λ=C/F=0.15 rice.The difference of carrier wave that transmitter is launched and receiver local oscillator output frequency is made as 200 hertz and 100 hertz of two kinds of situations.Carry out emulation according to above parameter configuration.
Fig. 8 is emulation under the condition of 200 hertz of frequency differences, and Fig. 9 is emulation under 100 hertz of conditions of frequency difference.This two figure and Utopian Fig. 6, Fig. 7 basically identical.Fig. 8, Fig. 9 have also considered actual environment such as additive white Gaussian noise.
With Fig. 8 is example analysis, f as can be known
a=420 hertz, f
b=20 hertz, by f
d=(f
a+ f
b)/2, Δ f=(f
a-f
bIt is (420+20)/2=220 hertz that)/2 can get maximum doppler frequency, and frequency difference is (420-20)=200 hertz, and then derives V=f for 220 hertz by maximum doppler frequency
d* λ=33 meter per seconds, the initial parameter of result and emulation is provided with identical.In like manner, analysis chart 9 also can push away exactly mobile station speed V.
As seen, just can be according to the present invention by four frequency f on the frequency spectrum
a, f
b,-f
a,-f
bCan release V fast and accurately.
Restrain intelligence in sum, the present invention is poor by the carrier frequency that overcome transmitter and launch and receiver local oscillator output frequency, thereby isolated the Doppler frequency spectrum relevant with mobile station speed, just can estimate mobile station speed by spectrum analysis, thereby avoided loaded down with trivial details design, easy, make velocity estimation quickly and accurately to travelling carriage.
Claims (4)
1. a kind of movement velocity method of measurement of travelling carriage in the mobile communication, it comprises: in spread spectrum communication, information to be passed (1) is taken advantage of spreading code earlier, carry out spread spectrum (2), spread-spectrum signal is sent modulator (3) to, multiply by modulating frequency f1 (5) when modulation signal, then through RF (6) and transmitting antenna (4) emission, it is characterized in that: send into demodulator (8) demodulation after receiving terminal receives signal, that adopt is the carrier frequency f2 of local oscillator herein, and both frequency differences are Δ f=|f
1-f
2| approximately be about 200 hertz, the signal after the demodulation is sent integration filter (11) to through despreading (10), the filtering harmonic component keeps baseband signal, and comprised carrier frequency frequency difference and Doppler frequency information in the baseband signal this moment, to information flow rate of doing work analysis of spectrum (12), can obtain f
a, f
b,-f
a,-f
bThe frequency values of these four frequency discontinuity points is by the frequency values of described four frequency discontinuity points, according to f
d=(f
a+ f
b)/2, Δ f=(f
a-f
bDoppler's peak frequency and frequency difference are calculated in)/2, adopt V=f
d* λ measures the movement velocity of travelling carriage.
2. a kind of movement velocity method of measurement of travelling carriage in the mobile communication according to claim 1 is characterized in that: described spectrum analysis technique adopts wavelet analysis method or fft analysis method.
3. a kind of movement velocity method of measurement of travelling carriage in the mobile communication according to claim 1 is characterized in that: described baseband signal is carried out fast fourier transform FFT or wavelet analysis, and the power spectrum curve that obtains signal flow is a shovel type curve.
4. according to a kind of movement velocity method of measurement of travelling carriage in claim 1 and the 2 described mobile communication, it is characterized in that: utilize measured Δ f, control local frequency f
2Size, can be as automatic frequency configuration.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011086076A CN1170443C (en) | 2001-07-09 | 2001-07-09 | Method for measuring motion speed of mobile station in mobile communication |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011086076A CN1170443C (en) | 2001-07-09 | 2001-07-09 | Method for measuring motion speed of mobile station in mobile communication |
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| CN1395429A CN1395429A (en) | 2003-02-05 |
| CN1170443C true CN1170443C (en) | 2004-10-06 |
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ID=4657410
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| CNB011086076A Expired - Fee Related CN1170443C (en) | 2001-07-09 | 2001-07-09 | Method for measuring motion speed of mobile station in mobile communication |
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Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100396144C (en) * | 2003-06-16 | 2008-06-18 | 华为技术有限公司 | Method of cross-region switching in mobile communication system |
| KR101002857B1 (en) * | 2003-09-16 | 2010-12-21 | 삼성전자주식회사 | Method and apparatus for estimating a velocity of a mobile terminal in a mobile communication system |
| JP4852723B2 (en) * | 2005-09-27 | 2012-01-11 | エスティー‐エリクソン、ソシエテ、アノニム | Method, program and module for estimating maximum Doppler frequency and oscillator frequency offset, and receiver including the module |
| CN101442786A (en) * | 2008-12-31 | 2009-05-27 | 华为技术有限公司 | Method and apparatus for determining target district |
| US8660596B2 (en) * | 2010-10-01 | 2014-02-25 | Mediatek Inc. | Electronic apparatus and associated frequency adjusting method |
| US8867392B2 (en) | 2011-06-16 | 2014-10-21 | Empire Technology Development Llc | Handoff of a mobile device moving at a high relative velocity to base stations for a wireless network |
| CN102299753B (en) * | 2011-06-28 | 2014-06-04 | 香港应用科技研究院有限公司 | Method for constructing wireless communication equipment to obtain motion sensing function |
| CN103220014B (en) * | 2013-03-20 | 2015-12-02 | 中国电子科技集团公司第十研究所 | Target speed-measuring method under high-speed frequency-hopping rate conditions |
| CN106154252B (en) * | 2015-03-31 | 2019-11-15 | 北京智谷睿拓技术服务有限公司 | Motion state of mobile terminal determines method and determining device |
| CN106154253B (en) * | 2015-03-31 | 2019-05-07 | 北京智谷睿拓技术服务有限公司 | Motion state of mobile terminal determines method and determining device |
| CN106304031B (en) * | 2015-05-30 | 2019-07-09 | 北京智谷睿拓技术服务有限公司 | Motion state of mobile terminal determines method and determining device |
| CN111385729A (en) * | 2018-12-11 | 2020-07-07 | 中兴通讯股份有限公司 | Speed measurement positioning method and terminal |
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2001
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