CN101699917B - Repeater and method for processing downlink radio-frequency signal by same - Google Patents
Repeater and method for processing downlink radio-frequency signal by same Download PDFInfo
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- CN101699917B CN101699917B CN2009101903457A CN200910190345A CN101699917B CN 101699917 B CN101699917 B CN 101699917B CN 2009101903457 A CN2009101903457 A CN 2009101903457A CN 200910190345 A CN200910190345 A CN 200910190345A CN 101699917 B CN101699917 B CN 101699917B
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Abstract
The invention is suitable for the field of communication and provides a repeater and a method for processing a downlink radio-frequency signal by the same. The repeater comprises a downlink channel module, an A/D conversion module, a digital medium-frequency board and a downlink gain amplifier, wherein the downlink channel module is used for converting an amplified downlink radio-frequency signal into a downlink simulation medium-frequency signal; the A/D conversion module is used for converting the downlink simulation medium-frequency signal into a downlink digital medium-frequency signal; the digital medium-frequency board generates a reference clock signal with the same frequency bias as the downlink digital medium-frequency signal; the downlink channel module is also used for regulating the amplified downlink radio-frequency signal according to the frequency bias of the reference clock signal and outputting a downlink radio-frequency signal without the frequency bias; and the downlink gain amplifier is used for amplifying the downlink radio-frequency signal without the frequency bias and outputting the downlink radio-frequency signal without the frequency bias to a second duplexer. The invention can effectively rectify the frequency bias generated by Doppler Effect and greatly improve the communication quality and the data efficiency of a mobile communication system.
Description
Technical field
The invention belongs to the communications field, relate in particular to a kind of repeater and utilize it to handle the method for downlink radio-frequency signal.
Background technology
Along with the development of urban economy, rail transportation system is born increasing passenger flow and is transported task.In April, 2007, the China Ministry of Railways carried out train speed raising the 6th time, and many main lines of China have moved Chinese bullet train CRH.Because CRH motor train unit train structure adopts closed, thereby very serious to the decay of wireless signal, make the mobile phone user's in the compartment speech quality obviously descend.
Vehicle-mounted direct discharging station is installed in the CRH compartment, just can be got around the car body loss of train, reduce the received field strength requirement outside the compartment, the railway base station along the line density of building a station will reduce greatly.Vehicle-mounted repeater is installed in CRH railway car outside with donor antenna, and network signal is received the back through amplifying, and in railway car, transmits; With outdoor received signal level satisfy-70dBm is an example; Then the coverage distance of single base station sub-district (antenna is hung high 40 meters) can reach 2 kilometers, under the unscreened condition in open Plain, can reach 4 kilometers especially; To reduce the railway density of building a station along the line so greatly, and the signal in the train that makes covers more reliable.
On the other hand; When having relative motion between emission source and the reception body; The frequency of the emission source emission information that the reception body receives and the frequency of emission source emission information are inequality, and this phenomenon is called Doppler effect, and the difference of receive frequency and tranmitting frequency is called Doppler frequency shift.High-speed railway CRH train speed per hour can reach 400 kilometers/hour, according to Doppler effect, produces frequency shift (FS):
Wherein C is the light velocity, and V is a relative moving speed, f
0It is the carrier frequency that transmits.。
The high ferro speed of a motor vehicle is with 400 kilometers/hour calculating, and Doppler frequency deviation is:
400×10
3/3600×3×10
8＝0.37ppm
This frequency deviation can greatly influence the speech quality and the data rate of GSM.
Summary of the invention
The object of the present invention is to provide a kind of repeater, the repeater that being intended to solve prior art provides can not be removed the problem of the frequency shift (FS) of Doppler effect generation well.
The present invention realizes like this; A kind of repeater; Comprise: second duplexer, frequency of oscillation generator, the up low noise amplifier, up channel module and the up gain amplifier that are linked in sequence successively with said second duplexer; Said frequency of oscillation generator is connected with said up channel module, and said repeater also comprises:
First duplexer is used for isolating downlink radio-frequency signal from radiofrequency signal;
Descending low noise amplifier is used for said downlink radio-frequency signal is carried out the low noise power amplification;
The down channel module is used for converting the downlink radio-frequency signal after amplifying to descending analog if signal;
The A/D modular converter is used for converting said descending analog if signal to descending digital medium-frequency signal;
The digital intermediate frequency plate is connected with said frequency of oscillation generator, is used for generating the reference clock signal that has with the identical frequency deviation of said descending digital medium-frequency signal according to the reference oscillation frequency that said descending digital medium-frequency signal and said frequency of oscillation generator generate;
Said down channel module also is used for the frequency deviation according to said reference clock signal, adjusts the downlink radio-frequency signal after the said amplification, the downlink radio-frequency signal of the no frequency deviation of output;
Descending gain amplifier is used for downlink radio-frequency signal to said no frequency deviation and amplifies and export said second duplexer to.
Another object of the present invention is to provide a kind of method of utilizing aforesaid repeater to handle downlink radio-frequency signal, said method comprises the steps:
From radiofrequency signal, isolate downlink radio-frequency signal through first duplexer;
Through descending low noise amplifier said downlink radio-frequency signal is carried out the low noise power amplification;
Low-converter through the down channel module converts the downlink radio-frequency signal after amplifying to descending analog if signal under the control of first phase-locked loop;
Intermediate-frequency filter carries out intermediate frequency filtering to said descending analog if signal;
Convert descending digital medium-frequency signal to through the descending analog if signal of A/D modular converter after with intermediate frequency filtering;
The digital intermediate frequency buttress generates the reference clock signal that has with the identical frequency deviation of said descending digital medium-frequency signal according to the reference oscillation frequency that said descending digital medium-frequency signal and frequency of oscillation generator generate;
Said down channel module is according to the frequency deviation of said reference clock signal, under the control of second phase-locked loop, adjusts the downlink radio-frequency signal after the said amplification, the downlink radio-frequency signal of the no frequency deviation of output through upconverter;
Descending gain amplifier amplifies the downlink radio-frequency signal of said no frequency deviation and exports said second duplexer to.
In the present invention, downlink radio-frequency signal gets into the down channel module and carries out down-converted through after amplifying; A branch road of the analog if signal that obtains is sent into the digital intermediate frequency plate and is carried out digitized processing; The digital intermediate frequency plate is controlled the phase-locked loop of up-conversion in the down channel module, through this closed-loop control after detecting the frequency deviation direction and frequency deviation size of radiofrequency signal; Adjust the frequency deviation of radiofrequency signal, thereby reach the effect of frequency correction.
Description of drawings
Fig. 1 is the structural representation of the repeater that provides of the embodiment of the invention;
Fig. 2 shows the structural representation of the down channel module that the embodiment of the invention provides;
Fig. 3 shows the structural representation of the digital intermediate frequency plate that the embodiment of the invention provides;
Fig. 4 is the FB(flow block) that utilizes repeater as shown in Figure 1 to handle the method for downlink radio-frequency signal provided by the invention.
Embodiment
In order to make the object of the invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with accompanying drawing and embodiment.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
In embodiments of the present invention, downlink radio-frequency signal gets into the down channel module and carries out down-converted through after amplifying; A branch road of the analog if signal that obtains is sent into the digital intermediate frequency plate and is carried out digitized processing; The digital intermediate frequency plate is controlled the phase-locked loop of up-conversion in the down channel module, through this closed-loop control after detecting the frequency deviation direction and frequency deviation size of radiofrequency signal; Adjust the frequency deviation of radiofrequency signal, thereby reach the effect of frequency correction.
The structure of the repeater that Fig. 1 provides for the embodiment of the invention for the ease of explanation, only shows the relevant part of the embodiment of the invention.This repeater comprises: first duplexer 11, descending low noise amplifier 12, down channel module 13, descending gain amplifier 14, frequency of oscillation generator 15, digital intermediate frequency plate 16, second duplexer 17, up low noise amplifier 18, up channel module 19, up gain amplifier 20, A/D modular converter 21.
Because train is in the high-speed motion, what receive can produce Doppler frequency shift from signal of base station.In addition in system because base station end has preferably for Doppler frequency shift handles, so up link need not to carry out frequency correction, only carries out frequency correction at down link.
Details are as follows for concrete process: radiofrequency signal is isolated downlink radio-frequency signal through first duplexer 11; Carrying out low noise through 12 pairs of said downlink radio-frequency signals of descending low noise amplifier again amplifies; Send into down channel module 13 and carry out down-converted, intermediate frequency filtering; Remove out of band signal; Send into digital intermediate frequency plate 16 after converting branch road of the intermediate-freuqncy signal that draws to digital medium-frequency signal through A/D modular converter 21 again, the clock that digital intermediate frequency plate 16 produces according to frequency of oscillation generator 15 is clock as a reference, and the Doppler frequency deviation direction of obtaining said digital medium-frequency signal is big or small with frequency deviation; Output has with the reference clock signal of the identical frequency deviation of said digital medium-frequency signal gives the reference clock of down channel module 13 as down channel module 13; The reference clock that said reference clock and frequency of oscillation generator 15 produce is controlled down channel module 13, thereby the frequency deviation of the downlink radio-frequency signal of down channel module 13 is imported in adjustment, reaches the purpose of frequency correction.
Fig. 2 shows the structure of the down channel module that the embodiment of the invention provides, and said down channel module comprises: first phase-locked loop 21 that is connected with said frequency of oscillation generator 15; Be connected with said first phase-locked loop 21, be used for the downlink radio-frequency signal after amplifying is converted to the low-converter 22 of descending analog if signal; Be used for said descending analog if signal is carried out the intermediate-frequency filter 23 of intermediate frequency filtering; The coupler 24 that is connected with said intermediate-frequency filter 23; Be connected with said coupler 24, the descending analog if signal behind the intermediate frequency filtering that is used for said coupler 24 is coupled out converts the upconverter 25 of downlink radio-frequency signal to; Be connected in second phase-locked loop 26 between said upconverter 25 and the said digital intermediate frequency plate.As a preferred embodiment of the present invention; This down channel module also comprises crystal oscillator, is connected respectively with said second phase-locked loop 26 with said first phase-locked loop 21, is used to provide the locked clock of first phase-locked loop 21 and said second phase-locked loop 26; In the present embodiment, crystal oscillator is the 900M crystal oscillator.
Fig. 3 shows the structure of the digital intermediate frequency plate that the embodiment of the invention provides, and said digital intermediate frequency plate comprises: frequency search device 31, section's Stas ring 32 and sinusoidal digital signal generator 33.
Fig. 4 is the FB(flow block) that utilizes repeater as shown in Figure 1 to handle the method for downlink radio-frequency signal provided by the invention, and details are as follows:
In step 401, from radiofrequency signal, isolate downlink radio-frequency signal through first duplexer.
In step 402, said downlink radio-frequency signal is carried out the low noise power amplification through descending low noise amplifier.
In step 403, the low-converter through the down channel module converts the downlink radio-frequency signal after amplifying to descending analog if signal under the control of first phase-locked loop.
In step 404, intermediate-frequency filter carries out intermediate frequency filtering to said descending analog if signal.
In step 405, convert descending digital medium-frequency signal to through the descending analog if signal of A/D modular converter after with intermediate frequency filtering.
In step 406, the digital intermediate frequency buttress generates the reference clock signal that has with the identical frequency deviation of said descending digital medium-frequency signal according to the reference oscillation frequency that said descending digital medium-frequency signal and frequency of oscillation generator generate.
As one embodiment of the present of invention; The frequency search device obtains the carrier frequency of said descending digital medium-frequency signal; Can compose the peak through frequency spectrum searches and realizes; The digital medium-frequency signal that is about to input carries out the FFT conversion and obtains frequency spectrum, and the corresponding frequency in spectrum peak in frequency spectrum on a certain thresholding of search is the carrier frequency that need follow the tracks of, the carrier frequency of following the tracks of said descending digital medium-frequency signal through section's Stas ring again; Obtain Doppler frequency deviation information, generate the reference clock signal that has with the identical frequency deviation of said descending digital medium-frequency signal according to said Doppler frequency deviation information through sinusoidal digital signal generator at last.As a preferred embodiment of the present invention; After searching each frequency of descending digital medium-frequency signal through the frequency search device; The descending digital medium-frequency signal that to import through frequency converter is converted to 1MHz; The descending digital medium-frequency signal that will be converted to 1MHz through sampler is again sampled, and is drawn into the sample rate of 9.6MHz.Detailed process is: frequency converter is converted to 1MHz respectively with each frequency that the frequency search device searches; Extract through sampler again; Sample rate is 9.6MHz (above parameter is the optimized parameter that matlab emulation obtains), obtains the control word d (comprising Doppler frequency deviation information) of sinusoidal digital signal generator 33 again through section's Stas ring 32.If the control word of the sinusoidal digital signal generator 33 of 10MHz is d10m; The control word of the sinusoidal digital signal generator 33 of 1MHz is d1m; (d10m+ (d1m-d)/N) calculates the data control word that the 10MHz place has comprised the sinusoidal digital signal generator 33 of Doppler frequency deviation to through type; Wherein N is the frequency dividing ratio of phase-locked loop, is 900M/10M=90 herein.Controlling sinusoidal digital signal generator 33 at last, to export to down channel module 13 for referencial use.
In step 407, said down channel module is according to the frequency deviation of said reference clock signal, under the control of second phase-locked loop, adjusts the downlink radio-frequency signal after the said amplification, the downlink radio-frequency signal of the no frequency deviation of output through upconverter.
In step 408, descending gain amplifier amplifies the downlink radio-frequency signal of said no frequency deviation and exports said second duplexer to.
In embodiments of the present invention, downlink radio-frequency signal gets into the down channel module and carries out down-converted through after amplifying; A branch road of the analog if signal that obtains is sent into the digital intermediate frequency plate and is carried out digitized processing; The digital intermediate frequency plate is controlled the phase-locked loop of up-conversion in the down channel module, through this closed-loop control after detecting the frequency deviation direction and frequency deviation size of radiofrequency signal; Adjust the frequency deviation of radiofrequency signal, thereby reach the effect of frequency correction.This repeater can be applied to can reach 400 kilometers/hour in speed per hour in the high-speed railway CRH train, and the frequency deviation that can effectively correct Doppler effect and produced improves the speech quality and the data efficiency of GSM greatly.
The above is merely preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of within spirit of the present invention and principle, being done, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.
Claims (9)
1. repeater; Comprise: second duplexer, frequency of oscillation generator, the up low noise amplifier, up channel module and the up gain amplifier that are linked in sequence successively with said second duplexer; Said frequency of oscillation generator is connected with said up channel module; It is characterized in that said repeater also comprises:
First duplexer is used for isolating downlink radio-frequency signal from radiofrequency signal;
Descending low noise amplifier is used for said downlink radio-frequency signal is carried out the low noise power amplification;
The down channel module is used for converting the downlink radio-frequency signal after amplifying to descending analog if signal;
The A/D modular converter is used for converting said descending analog if signal to descending digital medium-frequency signal;
The digital intermediate frequency plate is connected with said frequency of oscillation generator, is used for generating the reference clock signal that has with the identical frequency deviation of said descending digital medium-frequency signal according to the reference oscillation frequency that said descending digital medium-frequency signal and said frequency of oscillation generator generate;
Said down channel module also is used for the frequency deviation according to said reference clock signal, adjusts the downlink radio-frequency signal after the said amplification, the downlink radio-frequency signal of the no frequency deviation of output;
Descending gain amplifier is used for downlink radio-frequency signal to said no frequency deviation and amplifies and export said second duplexer to.
2. repeater as claimed in claim 1 is characterized in that, said down channel module comprises:
First phase-locked loop that is connected with said frequency of oscillation generator;
Be connected with said first phase-locked loop, be used for the downlink radio-frequency signal after amplifying is converted to the low-converter of descending analog if signal;
Intermediate-frequency filter is used for said descending analog if signal is carried out intermediate frequency filtering;
The coupler that is connected with said intermediate-frequency filter;
Be connected with said coupler, the descending analog if signal behind the intermediate frequency filtering that is used for said coupler is coupled out converts the upconverter of downlink radio-frequency signal to;
Be connected in second phase-locked loop between said upconverter and the said digital intermediate frequency plate.
3. repeater as claimed in claim 2 is characterized in that, said down channel module also comprises:
Be connected respectively with said second phase-locked loop with said first phase-locked loop, be used to provide the crystal oscillator of the locked clock of said first phase-locked loop and said second phase-locked loop.
4. repeater as claimed in claim 2 is characterized in that, said digital intermediate frequency plate comprises:
The frequency search device is used to obtain the carrier frequency of said descending digital medium-frequency signal;
Section's Stas ring, the carrier frequency that is used to follow the tracks of said descending digital medium-frequency signal is obtained Doppler frequency deviation information;
Sinusoidal digital signal generator generates the reference clock signal that has with the identical frequency deviation of said descending digital medium-frequency signal according to said Doppler frequency deviation information.
5. repeater as claimed in claim 4 is characterized in that, said digital intermediate frequency plate also comprises:
Frequency converter is used for said descending digital medium-frequency signal is converted to 1MHz;
Sampler is used for the descending digital medium-frequency signal that is converted to 1MHz is sampled, and is drawn into the sample rate of 9.6MHz.
6. a method of utilizing repeater as claimed in claim 5 to handle downlink radio-frequency signal is characterized in that said method comprises the steps:
From radiofrequency signal, isolate downlink radio-frequency signal through first duplexer;
Through descending low noise amplifier said downlink radio-frequency signal is carried out the low noise power amplification;
Low-converter through the down channel module converts the downlink radio-frequency signal after amplifying to descending analog if signal under the control of first phase-locked loop;
Intermediate-frequency filter carries out intermediate frequency filtering to said descending analog if signal;
Convert descending digital medium-frequency signal to through the descending analog if signal of A/D modular converter after with intermediate frequency filtering;
The digital intermediate frequency buttress generates the reference clock signal that has with the identical frequency deviation of said descending digital medium-frequency signal according to the reference oscillation frequency that said descending digital medium-frequency signal and frequency of oscillation generator generate;
Said down channel module is according to the frequency deviation of said reference clock signal, under the control of second phase-locked loop, adjusts the downlink radio-frequency signal after the said amplification, the downlink radio-frequency signal of the no frequency deviation of output through upconverter;
Descending gain amplifier amplifies the downlink radio-frequency signal of said no frequency deviation and exports said second duplexer to.
7. method as claimed in claim 6; It is characterized in that;, under the control of first phase-locked loop, the downlink radio-frequency signal after amplifying is converted to before the step of descending analog if signal at said low-converter through the down channel module, said method also comprises the steps:
The locked clock of said first phase-locked loop and second phase-locked loop is provided through crystal oscillator.
8. method as claimed in claim 6; It is characterized in that the reference oscillation frequency generation that said digital intermediate frequency buttress generates according to said descending digital medium-frequency signal and frequency of oscillation generator has with the step of the reference clock signal of the identical frequency deviation of said descending digital medium-frequency signal and specifically comprises:
The frequency search device obtains the carrier frequency of the descending digital medium-frequency signal of input;
The carrier frequency that section's Stas ring is followed the tracks of said descending digital medium-frequency signal is obtained Doppler frequency deviation information;
Sinusoidal digital signal generator generates the reference clock signal that has with the identical frequency deviation of said descending digital medium-frequency signal according to said Doppler frequency deviation information.
9. method as claimed in claim 8 is characterized in that, in the carrier frequency that said section Stas ring is followed the tracks of said descending digital medium-frequency signal, obtains before the step of Doppler frequency deviation information, and said method also comprises the steps:
The descending digital medium-frequency signal that frequency converter will be imported is converted to 1MHz;
Sampler will be converted to the descending digital medium-frequency signal of 1MHz and sample, and be drawn into the sample rate of 9.6MHz.
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| CN101699917B true CN101699917B (en) | 2012-08-08 |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2847887B1 (en) | 2012-05-07 | 2020-03-18 | Andrew Wireless Systems GmbH | Doppler shift correction sub-system for communication device |
| CN103516645B (en) * | 2012-06-26 | 2016-06-29 | 泉州泽仕通科技有限公司 | A kind of two-way multi signal of high-speed mobile unit processes covering method |
| CN105376045B (en) * | 2015-12-23 | 2019-04-16 | 宽兆科技(深圳)有限公司 | It is a kind of can be to the radio frequency chip and mobile terminal that Doppler frequency shift is modified |
| CN113676243A (en) * | 2021-08-06 | 2021-11-19 | 成都德辰博睿科技有限公司 | Satellite signal monitoring and analyzing method and system |
| CN114978829B (en) * | 2022-05-12 | 2024-05-28 | 重庆金美通信有限责任公司 | Reverse frequency offset pre-correction mechanism of low-orbit satellite communication system |
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| CN101330324A (en) * | 2008-07-23 | 2008-12-24 | 深圳市云海通讯股份有限公司 | Method, apparatus and system for extracting synchronous indicating signal |
| CN101378276A (en) * | 2008-09-23 | 2009-03-04 | 林志华 | Method for correcting Doppler frequency difference of high speed moving body |
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| EP1650878A1 (en) * | 2002-05-16 | 2006-04-26 | Nokia Corporation | A method, a system and an electronic device for synchronizing a receiver |
| EP1980487A1 (en) * | 2007-04-11 | 2008-10-15 | EMS Technologies Canada, Ltd. | Aeronautical satellite TV repeater |
| CN101330324A (en) * | 2008-07-23 | 2008-12-24 | 深圳市云海通讯股份有限公司 | Method, apparatus and system for extracting synchronous indicating signal |
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