CN102843318B - The device and method that a kind of repeater echo based on additional signal is offset - Google Patents

Abstract

The invention discloses the device and method that a kind of repeater echo based on additional signal is offset.This device comprises receiver module, Digital Down Converter Module, additional signal module, echo channel parameter matrix estimation module, signal subtraction module, signal plus module, Digital Up Convert module, power amplifier module and transmitter module; The method comprises the following steps: A, repeater initialization; B, generation additional signal; After the signal plus that C, additional signal and the repeater after Echo Cancellation receive, successively through Digital Up Convert and power amplification process, be input to transmitter module radio frequency and export.In the present invention, additional signal does not cause signal disturbing, and the relative error of main footpath attenuation coefficient is little, effectively eliminates echo interference, and data length during computing is little, hardware implementing is simple and after offsetting, signal does not exist the process restrained gradually.The device and method that the present invention offsets as a kind of repeater echo based on additional signal can be widely used in communication technical field.

Description

The device and method that a kind of repeater echo based on additional signal is offset

Technical field

The present invention relates to the communications field, the device and method that especially a kind of repeater echo based on additional signal is offset.

Background technology

Existing digital high-frequency amplification station adopts following know-why to carry out Echo cancellation mostly: by carrying out certain process to the signal sent and the mixed signal containing echo noise received, estimate the characteristic parameter of echo path, produce the echo-signal of a simulation in inside, repeater, from the mixed signal received, deduct this signal to realize Echo cancellation.Due to echo path is normally unknown and time become, so general employing sef-adapting filter carrys out estimated echo path.Wherein based on sef-adapting filter application the most extensive of least mean-square error (LeastMeanSquare, be called for short LMS) principle.

The simple Echo Cancellation technology introduced based on sef-adapting filter principle below:

Echo Cancellation know-why block diagram based on sef-adapting filter principle is shown in Fig. 1.The X that transmits is fed back to inner ART network device and filters internal W simultaneously, and the error signal E that ART network device obtains after utilizing this signal and Echo Cancellation process estimates outside echo channel, and the result estimated is assigned to filter W.When filter W and outside echo channel equivalence, then transmit through outside echo channel be coupled to reception antenna formed echo-signal X' equal with the estimate echo signal Y that filter W exports, through additive operation link, the two is cancelled out each other, thus makes only to comprise donor signal S (not considering the impact of interchannel noise) in E.When ART network device adopts LMS algorithm, need to ensure that E and X is uncorrelated, be provided with time delay process for this reason, the correlation of E and X can be reduced or eliminate by adjustment time delay.

Obviously, the effect of the Echo Cancellation of above-mentioned principle depends primarily on the estimated accuracy of ART network device to outside echo channel.For the ART network device based on LMS principle, its condition of convergence can be derived as follows.

Suppose: outer channel impulse response is H=[h ₁h ₂h _n] ^t, the impulse response W=[w of filter W ₁w ₂... w _n] ^t, L is the exponent number of filter; Donor signal S={s (n) } _n=1,2..., echo-signal X'={x'(n) } _n=1,2..., the echo-signal Y={y (n) of estimation } _n=1,2..., error signal E={e (n) } _n=1,2...; W ⁿrepresent the W value in n moment, X ⁿrepresent that the n moment transmits the value of X, X ⁿ=[x (n), x (n-1) ... x (n-L+1)]; Donor signal during moment n is s (n), and echo-signal is x'(n), error signal is the echo-signal that e (n), X obtain through filter W estimating: y (n)=X ⁿw ⁿ.

The weight coefficient renewal equation of known LMS adaptive algorithm is:

W ⁿ⁺¹＝W ⁿ+2ue(n)X ⁿ(1.1)

Wherein e (n)=s (n)+x'(n)-y (n), u be the step factor of LMS adaptive algorithm

Then can obtain:

W ⁿ⁺¹＝W ⁿ+2us(n)X ⁿ+2u[x'(n)-y(n)]X ⁿ(1.2)

W ⁿ⁺²＝W ⁿ⁺¹+2us(n+1)X ⁿ⁺¹+2u[x'(n+1)-y(n+1)]X ⁿ⁺¹(1.3)

……

W ^n+m+1＝W ^n+m+2us(n+m)X ^n+m+2u[x'(n+m)-y(n+m)]X ^n+m(1.4)

1.1 ~ 1.4 formulas of conclusion can obtain:

$W^{n+m+1}=W^n+2u\underset{m=0}{\Σ}s\left(n+m\right)X^{n+m}+2u\underset{m=0}{\Σ}\[x^{\′}(n+m)-y(n+m)\]X^{n+m}---\left(1.5\right)$

Can find out, weight coefficient W be made no longer to upgrade, i.e. algorithmic statement, the rear binomial of above formula need be made to go to zero.Wherein, for the related operation of S and X, the correlation of S and X can be reduced or eliminate by the time delay process in adjustment Fig. 1, thus make this be tending towards or equal zero.And all can go to zero in both cases.The first situation, signal X' is equal with signal Y, and the echo namely estimated is equal with actual echo; The second situation, signal X', signal Y are uncorrelated with signal X respectively.When meeting the correlation requirement of S and X, for ensureing the equal sufficient and necessary condition being sef-adapting filter and restraining of echo-signal of echo-signal and the reality estimated, the appearance of the second situation need be avoided.For avoiding the second situation to occur, should ensure that signal X', signal Y are relevant to signal X respectively, and correlation is the bigger the better.

Can learn from discussion above, this algorithmic statement need meet following two requirements:

One, need ensure that donor signal S is uncorrelated with the signal X sending into ART network device;

Two, need ensure that actual echo-signal X', the echo-signal Y of estimation and the signal X of feeding ART network device have certain correlation, and correlation is the bigger the better.

The characteristic of echo cancellation system due to its filters internal Step wise approximation outer channel is realized based on sef-adapting filter, for time varying channel, the speed speed approached depends on the step-length of adaptive algorithm, and step-length is longer, approaches faster, but error is larger, otherwise step-length is shorter, precision is higher, but velocity of approch is slower, for time variation channel faster, adaptive step and error are a pair insurmountable contradiction.

Common adaptive algorithm has least-mean-square error algorithm (LMS), block least-mean-square error algorithm (BLMS), normalized mean squared error algorithm (NLMS) etc.These algorithms have study and follow-up control, the needs of optimum filtering can be met, but it is the process of successive iteration that its weight coefficient upgrades, its convergence rate and the statistical property degree of dependence of steady-state error to input signal higher, amount of calculation is large and dynamic tracking capabilities is limited.

Find by carrying out analysis to the condition of convergence of the sef-adapting filter based on LMS principle, the existing adaptive filter algorithm utilizing time delay decorrelation, also exists from principle and can not ensure to make multipath signal meet the limitation of the condition of convergence simultaneously.Outer channel be single footpath channel or the main footpath echo channel only considering multipath channel time, the adaptive filter algorithm of existing time delay decorrelation can come by the time delay in adjustment Fig. 1 with good conditionsily meet Section 1 requirement, but cannot ensure Section 2 requirement.Two requirements to be met simultaneously, need to make certain improvements to the adaptive filter algorithm of existing time delay decorrelation.When outer channel is multipath channel, which footpath echo-signal of the signal X and multipath signal that send into ART network device meets Section 2 requirement, then can ensure the counteracting to this footpath echo-signal.So, based on the Echo Cancellation technology of this principle, even if more satisfactory effect can be obtained when only having main footpath echo in echo-signal or main footpath echo proportion is very large, when echo channel become be made up of the path that multiple attenuation coefficient is roughly the same time, Echo Cancellation effect may sharply worsen.This conclusion can explain the phenomenon having repeater in the situations such as vehicle passes through that self-excitation occurs near the repeater that explanation is observed in actual use.

Summary of the invention

In order to solve above-mentioned technical problem, the object of this invention is to provide high accuracy, low error and to be applicable to outer channel be the device that a kind of repeater echo based on additional signal of multipath channel is offset.

Another object of the present invention be to provide a kind ofly estimate that echo channel impulse response relative error is less, computing time data length little, complexity is low, real-time good, hardware implementing is simply based on the repeater echo counteracting method of additional signal.

In order to solve the problems of the technologies described above, a kind of technical scheme of the present invention is:

The device that a kind of repeater echo based on additional signal is offset, described device includes receiver module, additional signal module and echo channel parameter matrix estimation module, the output of described receiver module is connected with Digital Down Converter Module in turn, signal subtraction module, signal plus module, Digital Up Convert module, power amplifier module and transmitter module, the output input of connection signal summation module and the input of echo channel parameter matrix estimation module respectively of described additional signal module, the output of described Digital Down Converter Module is also connected to the input of echo channel parameter matrix estimation module, the output of described signal plus module is also connected to the input of echo channel parameter matrix estimation module respectively, the output of described echo channel parameter matrix estimation module is connected to the input of signal subtraction module.

Further, described echo channel parameter matrix estimation module includes the first cross-correlation submodule, the second cross-correlation submodule, deconvolution submodule, correcting process submodule and estimates echo channel submodule; The output of described first cross-correlation submodule and the second cross-correlation submodule is all connected to the input of deconvolution submodule, and deconvolution submodule connects correcting process submodule successively, estimates echo channel submodule; The output of described Digital Down Converter Module and the output of additional signal module are connected to the input of the first cross-correlation submodule, the output of described signal plus module and the output of additional signal module are connected to the input of the second cross-correlation submodule, and the output of described estimation echo channel submodule is connected to the input of signal subtraction module.

Further, the additional signal that described additional signal module produces is stored in additional signal module, and described additional signal and the useful base station signal cross correlation that receiver module receives after Digital Down Convert are approximately 0.

Another kind of technical scheme of the present invention is:

Based on the method that the repeater echo of additional signal is offset, said method comprising the steps of:

A, repeater initialization;

B, generation additional signal;

After the signal plus that C, additional signal and the repeater after Echo Cancellation receive, successively through Digital Up Convert and power amplification process, be input to transmitter module radio frequency and export.

Further, described step B comprises following sub-step:

B1, wait for Δ τ second, open the enable switch SHIFT of add-on module;

B2, start to record additional signal z (n) from the enable switch SHIFT start-up time of add-on module, be stored in register REG0;

B3, when the data amount check stored in REG0 reaches Q, close enable switch SHIFT, wherein Q is the sampling number of additional signal.

Further, the Echo Cancellation process in described step C comprises following sub-step:

Signal y (n) that C1, additional signal z (n) and repeater receive adopts the data block processing mode based on discrete digital signal, calculates the cross-correlation function R of these two signals _zym (), is stored in register REG1;

Signal x (n) that C2, additional signal z (n) and repeater are launched adopts the data block processing mode based on discrete digital signal, calculates the cross-correlation function R of these two signals _zxm (), is stored in register REG2;

C3, using the input signal of the output signal of above two cross-correlation submodules as deconvolution submodule be stored in register REG3;

C4, correction operation;

The value stored in C5, reading register REG3 for the repeater echo channel parameter matrix that this method is estimated;

C6, according to echo channel parameter matrix the estimating received signal calculated, subtracts each other signal y (n) that estimating received signal and actual repeater receive and makes Echo Cancellation and operate.

Further, the frequency of described additional signal is the frequency being in the useful base station signal spectrum interposition in repeater.

Further, the power ratio repeater of described additional signal receives little more than the 20dB of power of useful base station signal.

Further, the sequence length carrying out processing in described cross-correlation submodule gets L=22.

The invention has the beneficial effects as follows: the device that the repeater echo that the present invention is based on additional signal is offset utilizes the single frequency sinusoidal signal adding amplitude less at the spectrum interposition place of base station useful signal to assist channel estimating, and adding signal can not cause signal disturbing to the cellphone subscriber of overlay area, repeater.

Another one beneficial effect of the present invention is: the present invention is based on the repeater echo counteracting method of additional signal under the frequency selective fading channels model of COST207 standard, the relative error of main footpath attenuation coefficient is 1.7417 × 10 ^-5estimate that echo can follow the tracks of actual ghosts preferably, thus reach the object effectively eliminating echo interference, and estimate that echo channel impulse response relative error is less, data length during computing is little, complexity is low, real-time is good, hardware implementing is simple, and after offsetting, signal does not exist the process restrained gradually.

Accompanying drawing explanation

Fig. 1 is the Echo Cancellation know-why block diagram based on sef-adapting filter principle;

Fig. 2 is the theory diagram of the device and method of offsetting based on the repeater echo of additional signal;

Fig. 3 is the structured flowchart of the device of offsetting based on the repeater echo of additional signal.

Fig. 4 is the flow chart of steps of repeater echo counteracting method one embodiment based on additional signal;

Fig. 5 is the flow chart of steps of another embodiment of repeater echo counteracting method based on additional signal.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described further:

As shown in Figure 3, the device that a kind of repeater echo based on additional signal is offset, this device includes receiver module, additional signal module and echo channel parameter matrix estimation module, the output of described receiver module is connected with Digital Down Converter Module in turn, signal subtraction module, signal plus module, Digital Up Convert module, power amplifier module and transmitter module, the output input of connection signal summation module and two inputs of echo channel parameter matrix estimation module respectively of described additional signal module, the output of described Digital Down Converter Module is also connected to the input of echo channel parameter matrix estimation module, the output of described signal plus module is also connected to two inputs of echo channel parameter matrix estimation module respectively, the output of described echo channel parameter matrix estimation module is connected to the input of signal subtraction module.

Be further used as preferred embodiment, described echo channel parameter matrix estimation module includes the first cross-correlation submodule, the second cross-correlation submodule, deconvolution submodule, correcting process submodule and estimates echo channel submodule; The output of described first cross-correlation submodule and the second cross-correlation submodule is all connected to the input of deconvolution submodule, and deconvolution submodule connects correcting process submodule successively, estimates echo channel submodule; The output of described Digital Down Converter Module and the output of additional signal module are connected to the input of the first cross-correlation submodule, the output of described signal plus module and the output of additional signal module are connected to the input of the second cross-correlation submodule, and the output of described estimation echo channel submodule is connected to the input of signal subtraction module.

Be further used as preferred embodiment, the additional signal that described additional signal module produces is stored in additional signal module, and described additional signal and the useful base station signal cross correlation that receiver module receives after Digital Down Convert are approximately 0.

As shown in Figure 4, the method that a kind of repeater echo based on additional signal that a specific embodiment provides is offset, the method comprises the following steps:

A, repeater initialization;

B, generation additional signal;

After the signal plus that C, additional signal and the repeater after Echo Cancellation receive, successively through Digital Up Convert and power amplification process, be input to transmitter module radio frequency and export.

As shown in Figure 5, the method that a kind of repeater echo based on additional signal that another specific embodiment provides is offset, the method comprises the following steps:

A, repeater initialization;

B1, wait for Δ τ second, open the enable switch SHIFT of add-on module, if enable switch start-up time is t ₀, wherein Δ τ is from repeater receiver module Received signal strength, and exports the time delay of process through Digital Down Converter Module;

B2, from t ₀moment starts to record additional signal z (n), is stored in register REG0;

B3, when the data amount check stored in REG0 reaches Q, close enable switch SHIFT, wherein Q is the sampling number of additional signal;

Signal y (n) that C1, additional signal z (n) and the repeater receiver module that are produced by add-on module receive all is input to cross-correlation submodule, adopt the data block processing mode based on discrete digital signal, the data block length carrying out echo channel estimation is designated as N, calculates the cross-correlation function R of these two signals _zy(m), wherein m ∈ [-(N-1), (N-1)], is stored in register REG1;

The radiofrequency signal x (n) that C2, additional signal z (n) and the repeater transmitter module that are produced by add-on module launch all is input to cross-correlation submodule, the data block length of z (n) and x (n) is designated as N, calculates the cross-correlation function R of these two signals _zx(m), wherein m ∈ [-(N-1), (N-1)], is stored in register REG2;

C3, using the input signal of the output of above two cross-correlation submodules as deconvolution submodule, deconvolution submodule export for estimating the parameter matrix of echo channel, be stored in register REG3, the maximum of getting REG3 is MAX1;

C4, correction operation:

If then by corresponding in register REG3 value is set to 0;

If then retain in register REG3 corresponding value;

The value stored in C5, reading register REG3 for the repeater echo channel parameter matrix that this method is estimated.

C6, according to echo channel parameter matrix the estimating received signal calculated, subtracts each other signal y (n) that estimating received signal and actual repeater receive and makes Echo Cancellation and operate;

After the signal plus that C7, the additional signal and the repeater receiver module after Echo Cancellation that are produced by add-on module receive, enter Digital Up Convert module, through power amplifier module, be input to transmitter module.

Be further used as preferred embodiment, repeater echo bucking-out system specifically arranges as follows:

Before S1, described additional signal module position are arranged on repeater Digital Up Convert module position;

S2, described additional signal frequency should be and be in the frequency that repeater receives useful base station signal spectrum interposition;

S3, described added signal power should receive little more than the 20dB of the power of useful base station signal than repeater;

S4, described additional signal launch time should in repeater initialization complete and in running order time;

S5, described additional signal sample frequency should be consistent with the sampling rate in the digital signal processing of repeater;

List entries length in S6, described cross-correlation submodule should be relevant with the actual ghosts channel of true environment residing for repeater, for estimating echo channel parameter matrix in real time, gets L=22.

The present invention proposes one and add a small-signal in forward signal, utilizes the algorithm that this signal is estimated echo channel, thus realizes the Echo Cancellation of repeater.This algorithm can realize the real-time estimation to echo channel, because the data block length carrying out channel estimating is less, even if under echo channel characteristic in time fast-changing situation, still have stronger follow-up control.

With reference to Fig. 2, the present invention estimates the actual ghosts channel parameter matrix of environment residing for repeater, realizes the system principle diagram of Echo Cancellation.Eliminate the processing procedure of radiofrequency signal to baseband signal in figure, only illustrate the signal of down link when repeater works in base band and flow to relation.

The donor signal that s (n) receives for repeater donor antenna, z (n) is additional signal, x (n) is the forward signal at retransmitting antenna place, repeater, x'(n) be the echo-signal that repeater forward signal produces through actual ghosts channel, y (n) is the signal that donor antenna receives, by s (n) and x'(n) two parts form.The effect of echo channel estimation module is the model parameter being calculated echo channel by x (n), y (n) and z (n), and gives estimation echo channel.X (n) is input to and estimates that echo channel obtains estimating echo by y (n) with difference signal after subtracting each other is designated as e (n), if estimate, echo channel is of equal value with actual echo channel, then with x'(n) equal, e (n) is exactly pure donor signal s (n), thus achieves Echo cancellation.

It is pointed out that in forward signal and contain additional signal z (n), so must ensure that this signal does not affect the normal reception of donor signal.In this article, z (n) is a single frequency sinusoidal signal, because donor signal is the known mobile communication signal of spectrum allocation may rule, therefore, only z (n) need be loaded into the edge of donor signal frequency band, and the energy of control z (n) is less than e (n) more than 20dB.For more generally situation, cognitive radio technology can be utilized to find out spectrum interposition near donor signal, and then realize the loading of additional signal.

Multidiameter fading channel is become when echo channel can be modeled as.But within an abundant short time period, the time variation of echo channel can be ignored.In the signal processing that this data length is less, echo channel can be modeled as the FIR filter of tapped delay line form.The amplitude attenuation factor arranged in sequence of each for filter tap line just can be obtained the parameter matrix of actual ghosts channel:

H＝[h(1),h(2),…,h(n),…,h(M)](3.1)

Wherein, M is the number of element in actual ghosts channel parameter matrix, i.e. the exponent number of FIR filter.The concrete value of M is determined by the maximum delay amount of echo and sample frequency.To the estimation of actual ghosts channel, by x (n), y (n) and z (n), H is estimated exactly.

Algorithm Analysis: algorithm adopts the data block processing mode based on discrete digital signal herein, and the data block length carrying out echo channel estimation is designated as N, then the cross-correlation function R of additional signal z (n) and repeater Received signal strength y (n) _zy(m) be:

$\begin{array}{c}{R}_{zy}\left(m\right)=E\[z\left(n\right)y\left(n+m\right)\]\\ =E\{z\left(n\right)\[s\left(n+m\right)+h\left(n\right)\⊗x\left(n+m\right)\]\}\\ =E\{z\left(n\right)\[s\left(n+m\right)+\underset{k=-\mathrm{\∞}}{\overset{+\mathrm{\∞}}{\Σ}}h\left(k\right)x\left(n+m-k\right)\]\}\\ =R_{zs}\left(m\right)+E\{z\left(n\right)\[\underset{k=-\mathrm{\∞}}{\overset{+\mathrm{\∞}}{\Σ}}h\left(k\right)x\left(n+m-k\right)\}\\ =R_{zs}\left(m\right)+\underset{k=-\mathrm{\∞}}{\overset{+\mathrm{\∞}}{\Σ}}h\left(k\right)E\[z\left(n\right)x\left(n+m-k\right)\]\\ =R_{zs}\left(m\right)+\underset{k=-\mathrm{\∞}}{\overset{+\mathrm{\∞}}{\Σ}}h\left(k\right)R_{zx}\left(m-k\right)\\ =R_{zs}\left(m\right)+h\left(m\right)\⊗R_{zx}\left(m\right)\end{array}---\left(3.2\right)$

Wherein, represent linear convolution; R _zsm () is the cross-correlation function between additional signal z (n) and donor signal s (n); R _zxm () is the cross-correlation function between additional signal z (n) and forward signal x (n); H (m) is the element of in actual ghosts channel parameter matrix H; M ∈ [-(N-1), (N-1)].

If R _zsm () meets (3.3) formula:

R _zs(m)≈0(3.3)

Namely the cross correlation between additional signal z (n) and donor signal s (n) is less, R _zsm () is approximately 0.Then (3.2) formula can abbreviation be:

$R_{zy}\left(m\right)=h\left(m\right)\⊗R_{zx}\left(m\right)---\left(3.4\right)$

From above formula, each element value of actual ghosts channel parameter matrix H can by R _zy(m) deconvolution R _zxm () obtains.

Order

n＝m+N

And substitute into (3.4) formula, can obtain:

$R_{\mathrm{zy}}(n-N)=h(n-N)\⊗R_{\mathrm{zx}}(n-N)---\left(3.5\right)$

If R _zx(-N+1) ≠ 0, (3.5) formula can be written as time domain iterative solution convolution form:

$\hat{h}\left(n\right)\≈\left\{\begin{array}{cc}{R}_{zy}\left(-N+1\right)/R_{zx}\left(-N+1\right)& n=1\\ \[R_{zy}\left(n-N\right)\underset{k=-N+1}{\overset{n-N-1}{\Σ}}h\left(n-N-k\right)R_{zx}\left(k+1\right)\]/R_{zx}\left(-N+\right)& 2\≤n\≤2N-1\end{array}\right.---\left(3.6\right)$

Order $\hat{H}=\[\hat{h}\left(1\right),\hat{h}\left(2\right),...,\hat{h}\left(n\right),...,\hat{h}(2N-1)\],$ For estimating echo channel parameter matrix.

From the angle analysis of mathematics, comprehensive (3.1) formula and (3.4) Shi Ke get, as long as the data block length carrying out channel estimating is got integer value.But from the angle analysis of physical significance, the number M of element in actual ghosts channel parameter matrix, show that any echo effect of current time can have influence on a follow-up M sampled point, in other words the echo effect of M the sampled point in moment can have influence on current time certain a bit.Therefore, the data block length N carrying out channel estimating should get the integer value being more than or equal to M.

In echo channel estimation procedure, because in actual ghosts channel parameter matrix, the number M of element is unknown quantity, for ensureing to estimate there is certain remaining simultaneously for the consideration of estimated accuracy, suitably should strengthen the value of N.There will be like this the problem inconsistent with element number in H, it is right now to need carry out correcting process.(3.6) formula of analysis is known, R _zx(n-N) item fully little in can cause current solution increase, iterative process can aggravate the trend that further element progressively increases, and finally exists middlely will there is ghost peak, and be easily judged to main footpath echo, have a strong impact on the performance of algorithm.Therefore, according to R _zx(n-N) in, the mean value of several elements initial arranges appropriate threshold value, by R _zx(n-N) position being less than or equal to threshold value in is designated as i, then the scope of (3.6) formula iterative can be modified to 2≤n≤i-1.

The relative error δ of main footpath echo amplitude attenuation coefficient is selected to assess for performance during Echo Cancellation this paper algorithm, the size of δ can reflect that algorithm estimates the quality of echo channel overall performance herein, relative error is less, illustrate and estimate echo channel impulse response more close to the echo channel impulse response of reality, the echo estimated more approaches actual ghosts, and the effect of Echo Cancellation is better; Otherwise then the effect of Echo Cancellation is poorer.

More than that better enforcement of the present invention is illustrated, but the invention is not limited to described embodiment, those of ordinary skill in the art can also make all equivalent variations or replacement under the prerequisite without prejudice to spirit of the present invention, and these equivalent distortion or replacement are all included in the application's claim limited range.

Claims (6)

1. based on the device that the repeater echo of additional signal is offset, it is characterized in that: include receiver module, additional signal module and echo channel parameter matrix estimation module; The output of described receiver module is connected with Digital Down Converter Module, signal subtraction module, signal plus module, Digital Up Convert module, power amplifier module and transmitter module in turn; The output of described additional signal module is connected to the input of signal plus module, and described echo channel parameter matrix estimation module includes the first cross-correlation submodule, the second cross-correlation submodule, deconvolution submodule, correcting process submodule and estimates echo channel submodule; The output of described first cross-correlation submodule and the second cross-correlation submodule is all connected to the input of deconvolution submodule; The output of described deconvolution submodule is connected by correcting process submodule and then with the input of estimation echo channel submodule; The output of described Digital Down Converter Module and the output of additional signal module are all connected to the input of the first cross-correlation submodule; The output of described signal plus module and the output of additional signal module are all connected to the input of the second cross-correlation submodule; The output of described estimation echo channel submodule is connected to the input of signal subtraction module.

2. the repeater echo based on the additional signal according to claim 1 device of offsetting, it is characterized in that: the additional signal that described additional signal module produces is stored in additional signal module, described additional signal and the useful base station signal cross correlation that receiver module receives after Digital Down Convert are approximately 0.

3., based on a repeater echo counteracting method for additional signal, it is characterized in that: said method comprising the steps of:

A, repeater initialization;

B, generation additional signal, described additional signal is single frequency sinusoidal signal, and its frequency is the frequency being in the useful base station signal spectrum interposition in repeater;

After the signal plus that C, additional signal and the repeater after Echo Cancellation receive, successively through Digital Up Convert and power amplification process, be input to transmitter module radio frequency and export;

Echo Cancellation process in described step C comprises following sub-step:

Signal y (n) that C1, additional signal z (n) and repeater receive adopts the data block processing mode based on discrete digital signal, calculates the cross-correlation function R of these two signals _zym (), is stored in register REG1, wherein m ∈ [-(N-1), (N-1)], N are the data block length that echo channel is estimated;

Signal x (n) that C2, additional signal z (n) and repeater are launched adopts the data block processing mode based on discrete digital signal, calculates the cross-correlation function R of these two signals _zxm (), is stored in register REG2, wherein m ∈ [-(N-1), (N-1)];

C3, using the input signal of the output of above two cross-correlation submodules as deconvolution submodule, the parameter matrix of deconvolution submodule output estimation echo channel be stored in register REG3, the maximum of getting REG3 is MAX1;

C4, correction operation:

If then by corresponding in register REG3 value is set to 0;

If then retain in register REG3 corresponding value;

The value stored in C5, reading register REG3 for the repeater echo channel parameter matrix that this method is estimated;

C6, according to echo channel parameter matrix the estimating received signal calculated, subtracts each other signal y (n) that estimating received signal and actual repeater receive and makes Echo Cancellation and operate.

4., according to the repeater echo counteracting method based on additional signal described in claim 3, it is characterized in that: described step B comprises following sub-step:

B1, wait for Δ τ second, open the enable switch SHIFT of add-on module;

B2, start to record additional signal z (n) from the enable switch SHIFT start-up time of add-on module, be stored in register REG0;

B3, when the data amount check stored in REG0 reaches Q, close enable switch SHIFT, wherein Q is the sampling number of additional signal.

5. according to the repeater echo counteracting method based on additional signal described in claim 3 or 4, it is characterized in that: the power ratio repeater of described additional signal receives little more than the 20dB of power of useful base station signal.

6. according to the repeater echo counteracting method based on additional signal described in claim 3 or 4, it is characterized in that: the sequence length carrying out processing in described cross-correlation submodule gets L=22.