CN101039305B - Balancing technique-based receiver and receiving method - Google Patents

Abstract

The present invention provides a receiver and receiving method based on equalization technology. The receiver and receiving method of the present invention reduce the calculation amount of the receiver, enhance the integral performance of the receiver, through frequency domain equalization processing on the received data, at the same time effectively eliminate multiple access interference and intersymbol interference. The present invention is of simple structure, not only satisfies the rapid increase of 3G wireless high-speed data service due to future internet and multimedia application, but also is with low cost, therefor providing a strong support for commercial application.

Description

A kind of receiver and method of reseptance based on balancing technique

Technical field

The invention belongs to wireless communication technology field, particularly a kind of receiver and method of reseptance based on balancing technique.

Background technology

Along with the following multimedia service demand growing to high speed data transfer, wireless data service will sharply increase, this just requires 3-G (Generation Three mobile communication system) should have some characteristics of suitable transmitting data service, as high data volume, high sudden, high reliability etc.

For the time division duplex in the 3G (Third Generation) Moblie (TDD) system, TD SDMA (TD-SCDMA) system for example, support that mobile phone TV services are important features, therefore need provide high-quality high speed data transfer business at broadcast message.As a rule, transport service at a high speed needs the receiver of high amount of calculation, and high-quality data transmission service needs performance excellent reception machine and method of reseptance.

And the TD-SCDMA system is an interference limiting system, the correlation of spreading code between the user, and having caused the interference between the user is that multiple access disturbs (MAI).In the middle of traditional reception detection system, other subscriber signals are all treated as noise, along with number of users increases, MAI becomes the major part of noise, thereby has limited the increase of power system capacity.Simultaneously, the multipath effect of wireless channel can cause intersymbol interference (ISI).Associated detection technique utilizes known multi-user's information of identification code and the transmitting channel information that estimates exactly, reduces MAI and ISI, under the situation that does not reduce signal to noise ratio, can improve system's error performance.

Associated detection technique mainly contains ZF (ZF) method and lowest mean square (MMSE) method, which kind of method no matter, all need to compare big matrix inversion operation, the computation complexity of algorithm is than higher, increase along with number of users, reception antenna, receiving symbol number, the amount of calculation of algorithm will increase, and particularly have difficulties when handling the long time delay multipath.As one of core technology of TD-SCDMA, joint-detection owing to have higher computation complexity, becomes one of main computational load of TD-SCDMA receiver when good demodulation performance is provided.

Therefore, how to provide a kind of receiver fast and method of reseptance just to become the technical problem that needs to be resolved hurrily.

Summary of the invention

Technical problem to be solved by this invention provides a kind of receiver and method of reseptance based on balancing technique, to reduce the amount of calculation of receiver, improves inbound pacing.

For addressing the above problem, it is as follows to the invention provides technical scheme:

A kind of receiver based on balancing technique comprises:

First fast fourier transformer is used for carrying out the conversion of time domain to frequency domain to receiving data, and the reception data frequency domain value that obtains is outputed to frequency-domain equalizer;

Channel estimator is used to carry out channel estimating, and the channel impulse response that obtains is outputed to preprocessor;

Preprocessor is used to carry out the noise power estimation and channel impulse response is carried out denoising, and the channel impulse response after the denoising is outputed to second fast fourier transformer;

Second fast fourier transformer is used for the channel impulse response after the denoising is carried out the conversion of time domain to frequency domain, and the channel impulse response frequency domain value after the denoising that obtains is outputed to frequency-domain equalizer;

Frequency-domain equalizer is used for carrying out the frequency domain equalization processing according to the channel impulse response frequency domain value after the denoising to receiving the data frequency domain value, and the equalization data frequency domain value that obtains is outputed to inverse fast Fourier transformer;

Inverse fast Fourier transformer is used for the equalization data frequency domain value is carried out the conversion of frequency domain to time domain, thresholding when obtaining equalization data.

Above-mentioned receiver, wherein, the frequency domain equalization Processing Algorithm that described frequency-domain equalizer carries out is:

Q (i)=M (i)/Λ (i), wherein, Q (i) is the i component of equalization data frequency domain value, and M (i) is for receiving the i component of data frequency domain value, and Λ (i) is the i component of the channel impulse response frequency domain value after the denoising.

Above-mentioned receiver, wherein, preprocessor further outputs to frequency-domain equalizer with the noise power estimated value;

Frequency-domain equalizer further carries out the frequency domain equalization processing according to the channel impulse response frequency domain value after noise power estimated value and the denoising to receiving the data frequency domain value, and specific algorithm is:

$Q\left(i\right)=\mathrm{conj}\left(\mathrm{\Λ}\left(i\right)\right)M\left(i\right)/({\left|\mathrm{\Λ}\left(i\right)\right|}^2+g\·{\mathrm{\σ}}_n^2),$ Wherein, Q (i) is the i component of equalization data frequency domain value, and conj is for asking conjugate operation, and M (i) is for receiving the i component of data frequency domain value, and Λ (i) is the i component of the channel impulse response frequency domain value after the denoising, σ _n ²Be the noise power estimated value, g is for adjusting parameter, g 〉=0.

Above-mentioned receiver wherein, also comprises matched filter, and thresholding is carried out matched filtering when being used for the equalization data to inverse fast Fourier transformer output, obtains demodulating data.

Above-mentioned receiver, wherein, the length of first fast fourier transformer, second fast fourier transformer, inverse fast Fourier transformer is 2 ^P, and satisfy: 2 ^P-1＜length (e)≤2 ^P, e is for receiving data.

A kind of method of reseptance based on balancing technique comprises step:

A, carry out the conversion of time domain, obtain receiving the data frequency domain value to frequency domain to receiving data;

B, carry out channel estimating, obtain channel impulse response;

C, carry out that noise power is estimated and channel impulse response is carried out denoising, obtain the channel impulse response after the denoising;

D, the channel impulse response after the denoising is carried out time domain to the conversion of frequency domain, obtain the channel impulse response frequency domain value after the denoising;

E, carry out frequency domain equalization and handle receiving the data frequency domain value, obtain the equalization data frequency domain value according to the channel impulse response frequency domain value after the denoising;

F, the equalization data frequency domain value is carried out the conversion of frequency domain to time domain, thresholding when obtaining equalization data.

Above-mentioned method of reseptance, wherein, in the step e, described frequency domain equalization Processing Algorithm is:

Q (i)=M (i)/Λ (i), wherein, Q (i) is the i component of equalization data frequency domain value, and M (i) is for receiving the i component of data frequency domain value, and Λ (i) is the i component of the channel impulse response frequency domain value after the denoising.

Above-mentioned method of reseptance, wherein,

In the step e, further carry out the frequency domain equalization processing according to the channel impulse response frequency domain value after noise power estimated value and the denoising to receiving the data frequency domain value, specific algorithm is:

$Q\left(i\right)=\mathrm{conj}\left(\mathrm{\Λ}\left(i\right)\right)M\left(i\right)/({\left|\mathrm{\Λ}\left(i\right)\right|}^2+g\·{\mathrm{\σ}}_n^2),$ Wherein, Q (i) is the i component of equalization data frequency domain value, and conj is for asking conjugate operation, and M (i) is for receiving the i component of data frequency domain value, and Λ (i) is the i component of the channel impulse response frequency domain value after the denoising, σ _n ²Be the noise power estimated value, g is for adjusting parameter, g 〉=0.

Above-mentioned method of reseptance wherein, also comprises step after the step F:

G, thresholding is carried out matched filtering during to equalization data, obtains demodulating data.

Above-mentioned method of reseptance, wherein,

Described time domain is undertaken by fast fourier transformer and inverse fast Fourier transformer respectively to the conversion of frequency domain and the conversion of frequency domain to time domain, and the length of described fast fourier transformer, inverse fast Fourier transformer is 2 ^P, and satisfy: 2 ^P-1＜length (e)≤2 ^P, e is for receiving data.

Receiver and method of reseptance based on balancing technique of the present invention by carrying out the frequency domain equalization processing to receiving data, when effectively eliminating multiple access interference and intersymbol interference, have reduced the amount of calculation of receiver, have improved the overall performance of receiver.Receiver structure of the present invention is simple, not only satisfied following the Internet and the multimedia application rapid increase to 3G wireless high-speed data business demand, and cost is lower, for the large-scale commercial applications application provides strong support.

Description of drawings

Fig. 1 is the receiver structure schematic diagram based on balancing technique of preferred embodiment of the present invention;

Fig. 2 is the structure of time slot figure of TD-SCDMA system.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, describe the present invention below in conjunction with the accompanying drawings and the specific embodiments.

Please refer to Fig. 1, the receiver based on balancing technique of preferred embodiment of the present invention comprises first fast fourier transformer 10, channel estimator 20, preprocessor 30, second fast fourier transformer 40, frequency-domain equalizer 50 and inverse fast Fourier transformer 60.

First fast fourier transformer 10, second fast fourier transformer 40 have identical structure and calculation function with inverse fast Fourier transformer 60, are used to carry out the conversion between time domain and the frequency domain.3 Fourier transformer length are 2 ^P, and satisfy: 2 ^P-1＜length (e)≤2 ^P, e is the reception data of receiver.

With the TD-SCDMA system is example, please refer to Fig. 2, and its reception data length at a time slot is 864 chips, thereby, the length of Fourier transformer is made as 1024.

Though show 3 independently fast fourier transformer among Fig. 1, also can only realize with a fast fourier transformer, promptly finish the function of these 3 fast fourier transformer by time-multiplexed mode with a fast fourier transformer.Can further reduce the receiver cost like this.

Wherein, 10 pairs of first fast fourier transformer receive data e and carry out the conversion of time domain to frequency domain, and the data M=FFT (e) after the conversion is outputed to frequency-domain equalizer 50, and FFT is a fast fourier transform in the formula.

Channel estimator 20 is used to carry out channel estimating, and delivery channel impulse response h is to preprocessor 30.Can utilize training sequence (Midamble) to obtain channel impulse response, channel impulse response mainly comprises time delay information and phase information.

In the TD-SCDMA system, the local Midamble sequence of channel estimator 20 usefulness is carried out the estimation of channel impulse response with the Midamble sequence that receives.Suppose that training sequence process rotation transformation before emission that the user uses is the complex-valued data B of Midamble _Midamble, the data that receive are R _Midamble, then can obtain following formula:

R _Midamble＝Gh+n

Wherein, n is a white noise, and G is the transition matrix that is made of basic Midamble sign indicating number.Because the noise robustness of the training sequence Midamble sign indicating number of selecting for use is better, The noise can be ignored, and therefore can obtain following formula:

R _Midamble＝Gh

Adopt following formula calculating channel impulse response h:

h＝IFFT(FFT(R _Midamble)./FFT(B _Midamble))

IFFT is a fast adverse Fourier transform in the formula ./expression contraposition is divided by, and the FFT/IFFT length here is fixed as 128.

Channel estimator 20 delivery channel impulse response h are carried out the noise power estimation and channel estimating are carried out denoising by preprocessor 30 to preprocessor 30.

Channel estimating is carried out noise power estimate that obtaining Noise Estimation is

Utilize noise gate then $\mathrm{\Γ}=\mathrm{\ϵ}\·{\widehat{\mathrm{\σ}}}_n^2,$ To the tap zero setting of energy among the h, thereby obtain data h ' after the denoising less than thresholding:

I=0 ..., 2 ^P-1

Preprocessor 30 outputs to second fast fourier transformer 40 with the data h ' after the denoising, with Noise Estimation

Output to frequency-domain equalizer 50.

Second fast fourier transformer 40 is carried out the conversion of time domain to frequency domain to the data h ' after the denoising, obtains frequency domain data Λ=FFT (h '), and Λ is outputed to frequency-domain equalizer 50.

Frequency-domain equalizer 50 is used for that the reception data are carried out the frequency domain equalization processing and obtains frequency domain value Q=FFT (s), and Q is outputed to inverse fast Fourier transformer 60, to eliminate multipath effect.

Output result after the equilibrium is

$Q\left(i\right)=\mathrm{conj}\left(\mathrm{\Λ}\left(i\right)\right)M\left(i\right)/({\left|\mathrm{\Λ}\left(i\right)\right|}^2+g\·{\widehat{\mathrm{\σ}}}_n^2)$ i＝0，...，2 ^P-1

Wherein, conj is for asking conjugate operation, and g is for adjusting parameter, g 〉=0, g=1 in the present embodiment.

When channel condition is relatively good, can get g=0.Thereby in another preferred embodiment of the present invention, the channel impulse response after 30 output of the preprocessor denoising is to second fast fourier transformer 40, and the input of frequency-domain equalizer 50 is M and Λ only, and the output result after the equilibrium is

Q(i)＝M(i)/Λ(i) i＝0，...，2 ^P-1

Frequency domain value Q after 60 pairs of equilibriums of inverse fast Fourier transformer carries out inverse Fourier transform, and frequency domain data is converted to time domain data, obtains the time thresholding s after the equilibrium.

Spreading factor SF＞1 of in system, using o'clock, also need s is carried out demodulation process, thereby, receiver of the present invention further comprises matched filter (figure does not show), matched filter carries out matched filtering (carrying out computing according to the Midamble Index in the control information) to s, obtains required last demodulation result d.

The present invention adopts the processing mode of frequency domain equalization, guarantees fast and effeciently that not only receiver carries out deconvolution to different delay, improve the overall performance of receiver, and amount of calculation has been compared remarkable advantages with traditional receiver.

Should be noted that at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from the spiritual scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (6)

1. the receiver based on balancing technique is characterized in that, comprising:

First fast fourier transformer is used for carrying out the conversion of time domain to frequency domain to receiving data, and the reception data frequency domain value that obtains is outputed to frequency-domain equalizer;

Channel estimator is used to carry out channel estimating, and the channel impulse response that obtains is outputed to preprocessor;

Preprocessor is used to carry out the noise power estimation and channel impulse response is carried out denoising, and the noise power estimated value is outputed to frequency-domain equalizer, and the channel impulse response after the denoising is outputed to second fast fourier transformer;

Second fast fourier transformer is used for the channel impulse response after the denoising is carried out the conversion of time domain to frequency domain, and the channel impulse response frequency domain value after the denoising that obtains is outputed to frequency-domain equalizer;

Frequency-domain equalizer is used for carrying out the frequency domain equalization processing according to the channel impulse response frequency domain value after noise power estimated value and the denoising to receiving the data frequency domain value, and the equalization data frequency domain value that obtains is outputed to inverse fast Fourier transformer;

Inverse fast Fourier transformer is used for the equalization data frequency domain value is carried out the conversion of frequency domain to time domain, thresholding when obtaining equalization data;

The frequency domain equalization Processing Algorithm that described frequency-domain equalizer carries out is:

$Q\left(i\right)=\mathrm{conj}\left(\mathrm{\Λ}\left(i\right)\right)M\left(i\right)/({\left|\mathrm{\Λ}\left(i\right)\right|}^2+g\·{\mathrm{\σ}}_n^2),$ Wherein, Q (i) is the i component of equalization data frequency domain value, and conj is for asking conjugate operation, and M (i) is for receiving the i component of data frequency domain value, and Λ (i) is the i component of the channel impulse response frequency domain value after the denoising, σ _n ²Be the noise power estimated value, g is for adjusting parameter, g 〉=0.

2. receiver as claimed in claim 1 is characterized in that:

Also comprise matched filter, thresholding is carried out matched filtering when being used for the equalization data to inverse fast Fourier transformer output, obtains demodulating data.

3. receiver as claimed in claim 1 is characterized in that:

The length of first fast fourier transformer, second fast fourier transformer, inverse fast Fourier transformer is 2 ^P, and satisfy: 2 ^P-1＜length (e)≤2 ^P, e is for receiving data.

4. the method for reseptance based on balancing technique is characterized in that, comprises step:

A, carry out the conversion of time domain, obtain receiving the data frequency domain value to frequency domain to receiving data;

B, carry out channel estimating, obtain channel impulse response;

C, carry out that noise power is estimated and channel impulse response is carried out denoising, obtain the channel impulse response after the denoising;

D, the channel impulse response after the denoising is carried out time domain to the conversion of frequency domain, obtain the channel impulse response frequency domain value after the denoising;

E, carry out frequency domain equalization and handle receiving the data frequency domain value, obtain the equalization data frequency domain value according to the channel impulse response frequency domain value after noise power estimated value and the denoising;

F, the equalization data frequency domain value is carried out the conversion of frequency domain to time domain, thresholding when obtaining equalization data;

In the step e, described frequency domain equalization Processing Algorithm is:

$Q\left(i\right)=\mathrm{conj}\left(\mathrm{\Λ}\left(i\right)\right)M\left(i\right)/({\left|\mathrm{\Λ}\left(i\right)\right|}^2+g\·{\mathrm{\σ}}_n^2),$ Wherein, Q (i) is the i component of equalization data frequency domain value, and conj is for asking conjugate operation, and M (i) is for receiving the i component of data frequency domain value, and Λ (i) is the i component of the channel impulse response frequency domain value after the denoising, σ _n ²Be the noise power estimated value, g is for adjusting parameter, g 〉=0.

5. method of reseptance as claimed in claim 4 is characterized in that, also comprises step after the step F:

G, thresholding is carried out matched filtering during to equalization data, obtains demodulating data.

6. method of reseptance as claimed in claim 4 is characterized in that:

Described time domain is undertaken by fast fourier transformer and inverse fast Fourier transformer respectively to the conversion of frequency domain and the conversion of frequency domain to time domain, and the length of described fast fourier transformer, inverse fast Fourier transformer is 2 ^P, and satisfy: 2 ^P-1＜length (e)≤2 ^P, e is for receiving data.

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