CN102163990B - Multi-user interference elimination method and base station - Google Patents

Abstract

The invention discloses a multi-user interference elimination method and a base station. The method comprises the following steps that: the base station reconstructs a midamble interference signal according to a frequency offset value of an interfering user; and the base station eliminates the reconstructed midamble interference signal from a received midamble signal to obtain the interference-eliminated midamble signal. By the method and the base station, the accuracy of interference signal reconstruction is improved, and the accuracy of subsequent frequency offset estimation is further improved.

Description

Multi-user interference eliminating method and base station

Technical field

The present invention relates to the communications field, in particular to a kind of multi-user interference eliminating method and base station.

Background technology

In mobile radio system, because base station and terminal are in the state of relative motion, the signal therefore received has Doppler frequency shift, and particularly under High-speed Circumstance, this frequency displacement is especially obvious.Doppler frequency shift can affect multi-upstream access success rate, handover success rate, also can have an impact to the capacity of system and covering.Therefore, base station and terminal must carry out frequency offset estimation and compensation, could meet operation quality requirement.

Frequency excursion algorithm in correlation technique utilizes known training sequence, such as, TD SDMA (Time Division-Synchronous Code Division MultipleAccess, referred to as TD-SCDMA) midamble code in system, do relevant by transmission sequence and receiving sequence, obtain the phase place deflection of receiving sequence, thus obtain frequency deviation.

In TD-SCDMA system, because multiple user is code division multiplexing, the midamble code therefore received is the result of multiple user midamble sequence separately after channel superposition.Therefore, from Received signal strength, how to isolate the signal of each user, so carry out respectively frequency deviation estimate be a stubborn problem.

The signal impulse response of each user is utilized to reconstruct the reception midamble sequence of each user in correlation technique, recycling interference elimination method, the midamble signal of other users in Received signal strength is eliminated, obtain the midamble receiving sequence of user to be estimated, and carry out frequency deviation estimation by this sequence.

Although above interference elimination method can eliminate the midamble Received signal strength of interference user, but interference signal has frequency deviation in systems in practice, especially when the large frequency deviation of high speed, the interference signal phase rotating that frequency deviation causes be can not ignore, said method have ignored the frequency deviation value of interference user, the error of reconstruct interference signal must be brought, and then also can affect the precision of frequency deviation estimation.

Summary of the invention

Main purpose of the present invention is to provide a kind of multi-user interference eliminating method and base station, to solve the problem.

One aspect of the present invention provides a kind of multi-user interference eliminating method, comprises the following steps: base station is according to the frequency deviation value reconstruct midamble interference signal of interference user; And the midamble interference signal of reconstruct is eliminated in base station from the midamble signal received, the midamble signal after the interference that is eliminated.

Preferably, base station comprises according to the frequency deviation value reconstruct midamble interference signal of interference user: base station calculates midamble interference signal b corresponding to i-th interference user _i=b _{i, 1}, b _{i, 2}... b _{i, j}b _{i, b-l}, wherein, $b_{i,j}=a_{i,j}\×e^{-2\mathrm{\π}\×{\stackrel{\‾}{f}}_d\×(j-64.5)/1280000},$ the frequency deviation value of i-th interference user, a _{i, j}given up the predetermined interference signal by the fractional chips of data symbol multi-path jamming, predetermined interference signal is the midamble interference signal that have ignored frequency deviation value impact that i-th interference user is corresponding, j=1,2, b-l, b are the length of midamble sequence, and l is the quantity of fractional chips, i=1,, N, N are the quantity of interference user.

Preferably, predetermined interference signal ${\stackrel{\‾}{a}}_i=h_i*{\stackrel{\‾}{m}}_i,$ Wherein, h _ibe the channel impulse response of i-th interference user, * calculates convolution, it is the midamble sequence that i-th interference user is corresponding.

Preferably, the midamble interference signal that reconstruct is eliminated in base station from the midamble signal received comprises: base station calculates the midamble signal after eliminating interference $r^{\′}=r-\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{b}_i,$ Wherein, r is the midamble signal that base station receives.

Preferably, base station also comprises eliminate the midamble interference signal of reconstruct from the midamble signal received after: frequency deviation estimation is carried out to eliminating the midamble signal after disturbing in base station, obtains the frequency deviation value of active user at current time.

Preferably, base station to eliminate interference after midamble signal carry out frequency deviation estimate comprise: base station to eliminate interference after midamble signal carry out frequency deviation estimation, obtain the instantaneous frequency deviation f of active user at current time _m, and to f _mthe smoothing frequency deviation rough estimate result obtaining current time base station adopts the data-signal that base station receives at current time is compensated, the data-signal after being compensated; Frequency deviation estimation is carried out to the data-signal after compensation in base station, obtains active user at the thin estimated result f of the frequency deviation of current time _d, and to f _dsmoothing, obtain the frequency deviation value of active user at current time

Preferably, to f _msmoothingly to comprise: calculate $\stackrel{\&OverBar;}{f_m}={\stackrel{\&OverBar;}{f}}_m^{*}\&times;(1-p)+f_m\&times;p,$ Wherein, it was a upper moment value, and ${\stackrel{\&OverBar;}{f}}_m^{*}\left(0\right)=0,$ P is smoothing factor, 0=< p <=1.

Preferably, to f _dsmoothingly to comprise: calculate ${\stackrel{\&OverBar;}{f_d}=\stackrel{\&OverBar;}{f}}_d^{*}\&times;(1-p)+f_d\&times;p,$ Wherein, it was a upper moment value, and ${\stackrel{\&OverBar;}{f}}_d^{*}\left(0\right)=0,$ P is smoothing factor, 0=< p <=1.

Preferably, the frequency deviation value of interference user was the frequency deviation value of interference user in a upper moment, or, for interference user is at the frequency deviation value of current time.

Another aspect of the present invention provides a kind of base station, comprising: interference reconstructed module, for the frequency deviation value reconstruct midamble interference signal according to interference user; Interference cancellation module, for eliminating the midamble interference signal of reconstruct from the midamble signal received, the midamble signal after the interference that is eliminated.

By the present invention, consider the impact of frequency deviation value when reconstruct interference signal, solve the problem that the interference signal error that reconstructs in correlation technique is larger, improve the accuracy of interference signal reconstruct, and then improve the accuracy that follow-up frequency deviation estimates.

Accompanying drawing explanation

Accompanying drawing described herein is used to provide a further understanding of the present invention, and form a application's part, schematic description and description of the present invention, for explaining the present invention, does not form inappropriate limitation of the present invention.In the accompanying drawings:

Fig. 1 is the structured flowchart of the base station according to the embodiment of the present invention;

Fig. 2 is the detailed block diagram of the base station according to the embodiment of the present invention;

Fig. 3 is the flow chart of the multi-user interference eliminating method according to the embodiment of the present invention;

Fig. 4 eliminates according to the multi-user interference of example 1 of the present invention and the flow chart of frequency offset estimation procedure; And,

Fig. 5 eliminates according to the multi-user interference of example 2 of the present invention and the flow chart of frequency offset estimation procedure.

Embodiment

Hereinafter also describe the present invention in detail with reference to accompanying drawing in conjunction with the embodiments.It should be noted that, when not conflicting, the embodiment in the application and the feature in embodiment can combine mutually.

First the structure of a kind of base station according to the embodiment of the present invention is introduced, can be improved the reconstruction accuracy of interference signal by this base station, and then improve the precision of frequency deviation estimation, Fig. 1 is the structured flowchart of the base station according to the embodiment of the present invention, as shown in Figure 1, this base station comprises:

Interference reconstructed module 12, for the frequency deviation value reconstruct midamble interference signal according to interference user;

Interference cancellation module 14, for eliminating the midamble interference signal of reconstruct from the midamble signal received, the midamble signal after the interference that is eliminated.

Particularly, as shown in Figure 2, above-mentioned interference reconstructed module 12 can comprise: the first computing unit 22, for calculating ${\stackrel{\&OverBar;}{a}}_i=h_i*{\stackrel{\&OverBar;}{m}}_i,$ Wherein, h _ibe the channel impulse response of i-th interference user, * calculates convolution, be the midamble sequence that i-th interference user is corresponding, i=1 ..., N, N are the quantity of interference user;

Chip selected cell 24, for giving up middle by l chip before data symbol multi-path jamming, obtain a _{i, 1}, a _{i, 2}... a _{i, b-l}, wherein, b is the length of midamble sequence;

Second computing unit 26, for calculating $b_{i,j}=a_{i,j}\&times;e^{-2\mathrm{\&pi;}\&times;{\stackrel{\&OverBar;}{f}}_d\&times;(j-64.5)/1280000},$ Obtain the interference midamble signal b that i-th interference user is corresponding _i=b _{i, 1}, b _{i, 2}... b _{i, b-l}, wherein, j=1,2 ..., b-l, it is the frequency deviation value of i-th interference user.

Above-mentioned base station may further include frequency deviation estimating modules 28, carries out frequency deviation estimation, obtain the frequency deviation value of active user at current time for the midamble signal after eliminating interference.

According to embodiments of the invention, additionally provide a kind of multi-user interference eliminating method, Fig. 3 is the flow chart of the multi-user interference eliminating method according to the embodiment of the present invention, and as shown in Figure 3, the method comprises the following steps:

Step S302, base station is according to the frequency deviation value reconstruct midamble interference signal of interference user; And,

Step S304, the midamble interference signal of reconstruct is eliminated in base station from the midamble signal received, the midamble signal after the interference that is eliminated.

Consider in correlation technique because the interference signal the reconstruction accuracy reconstruct that interference signal is included in the impact of frequency deviation in do not caused is low, and then cause the problem that frequency deviation evaluated error is larger, the method that the embodiment of the present invention provides brings the frequency deviation of interference user into reconstruct when disturbing and eliminating, take into full account the impact of frequency deviation on signal, thus improve the precision of reconstruct.

Preferably, step S302 comprises: base station calculates midamble interference signal b corresponding to i-th interference user _i=b _{i, 1}, b _{i, 2}... b _{i, j}b _{i, b-l}, wherein, $b_{i,j}=a_{i,j}\&times;e^{-2\mathrm{\&pi;}\&times;{\stackrel{\&OverBar;}{f}}_d\&times;(j-64.5)/1280000},$ the frequency deviation value of i-th interference user, a _{i, j}be given up the predetermined interference signal by the fractional chips of data symbol multi-path jamming, predetermined interference signal is the midamble interference signal (that is, adopting the interference signal that the interference signal reconstructing method in correlation technique produces) that have ignored frequency deviation value impact that i-th interference user is corresponding, j=1,2 ..., b-l, b is the length of midamble sequence, l is the quantity of fractional chips, i=1 ... N, N are the quantity of interference user.

In this process, give up by the fractional chips of data symbol multi-path jamming, made result of calculation more accurate.

The calculating formula of above-mentioned predetermined interference signal is: ${\stackrel{\&OverBar;}{a}}_i=h_i*{\stackrel{\&OverBar;}{m}}_i,$ Wherein, h _ibe the channel impulse response of i-th interference user, * calculates convolution, it is the midamble sequence that i-th interference user is corresponding.Above h _ican be obtained by channel estimation method of the prior art, concrete acquisition pattern does not repeat them here.

Preferably, step S304 specifically comprises: base station calculates the midamble signal after eliminating interference $r^{\&prime;}=r-\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{b}_i,$ Wherein, r is the midamble signal that base station receives.Preferably, interference user can be in current area, and other users' except active user is part or all of.

Preferably, after step S304, also comprise: frequency deviation estimation is carried out to eliminating the midamble signal after disturbing in base station, obtains the frequency deviation value of active user at current time.Signal after the elimination interference obtained by above-mentioned interference elimination method has higher accuracy, therefore, carries out frequency deviation estimate that the frequency offset estimation result obtained is also more accurate to the signal after above elimination interference.

In above process, base station can comprise the following steps the process that the midamble signal after elimination interference carries out frequency deviation estimation:

1, frequency deviation estimation is carried out to eliminating the midamble signal after disturbing in base station, obtains the instantaneous frequency deviation f of active user at current time _m, and to f _mthe smoothing frequency deviation rough estimate result obtaining current time particularly, to f _msmoothingly to comprise: calculate $\stackrel{\&OverBar;}{f_m}={\stackrel{\&OverBar;}{f}}_m^{*}\&times;(1-p)+f_m\&times;p,$ Wherein, it was a upper moment value, and ${\stackrel{\&OverBar;}{f}}_m^{*}\left(0\right)=0$ (that is, establish at initial time ${\stackrel{\&OverBar;}{f}}_m=0$ ), p is smoothing factor, 0=< p <=1.

2, base station adopts the data-signal that base station receives at current time is compensated, the data-signal after being compensated.

3, frequency deviation estimation is carried out to the data-signal after compensation in base station, obtains active user at the thin estimated result f of the frequency deviation of current time _d, and to f _dsmoothing, obtain the frequency deviation value of active user at current time particularly, to f _dsmoothingly to comprise: calculate $\stackrel{\&OverBar;}{f_d}={\stackrel{\&OverBar;}{f}}_d^{*}\&times;(1-p)+f_d\&times;p,$ Wherein, it was a upper moment value, and ${\stackrel{\&OverBar;}{f}}_d^{*}\left(0\right)=0$ (that is, establish at initial time ${\stackrel{\&OverBar;}{f}}_d=0$ ), p is smoothing factor, 0=< p <=1.

Because the length of midamble sequence is shorter, the arithmetic accuracy of frequency deviation is poor therefore to utilize midamble to estimate, must take into account the method that a step-down is made an uproar.Based on this, the instantaneous frequency deviation value that the embodiment of the present invention goes out for midamble sequencal estimation does smoothing processing, the strong correlation of the frequency deviation value utilizing the continuous period of the day from 11 p.m. to 1 a.m to carve, by temporal smothing filtering noise decrease on the impact of frequency offset estimation result, improves the precision estimated.

Preferably, the frequency deviation value of above interference user can be the frequency deviation value of interference user in a upper moment, or, also can be the frequency deviation value of interference user at current time.Particularly:

Eliminate and frequency deviation estimation if the interference user of active user has adopted said method to carry out interference, then active user can adopt interference user to carry out interference elimination and frequency deviation estimation at the frequency deviation value of current time, and in this case, result of calculation is more accurate;

If the interference user of active user not yet adopts said method to carry out interference and eliminates and frequency deviation estimation, then active user can adopt interference user to carry out interference elimination and frequency deviation estimation at the frequency deviation value in a upper moment, although the result of calculation that result of calculation in this case does not go up in a kind of situation is accurate, but, frequency deviation correlation is in time higher, history frequency deviation value being brought into interference signal reconstruct, also can obtaining more accurate interference signal for disturbing elimination.

It should be noted that, the concept in moment described above can be specially frame, subframe, time slot etc.

Be described in detail below in conjunction with the implementation procedure of example to the embodiment of the present invention.

Example 1

This example describe to each user walk abreast carry out disturb eliminate and frequency deviation estimate process.Fig. 4 is the flow chart of interference elimination according to example 1 of the present invention and frequency offset estimation procedure, and as shown in Figure 4, said process mainly comprises the following steps:

Step S401, base station is that each user stores a frequency deviation value, and initial time frequency deviation value is set to 0, in this example, is left in by frequency deviation value in frequency deviation register, but is not limited thereto.

Step S402, base station utilizes reception midamble code to carry out channel estimating, obtains the channel impulse response h of each user respectively;

Step S403, utilize the channel impulse response of each user and corresponding midamble sequence, and the frequency deviation value in frequency deviation register reconstructs the midamble signal that all users arrive base station side simultaneously.Wherein the restructuring procedure of i-th user is specific as follows:

1) by the result reconstructed reception signal of channel estimating be: ${\stackrel{\&OverBar;}{a}}_i=h_i*{\stackrel{\&OverBar;}{m}}_i,$ Wherein h _ibe the channel impulse response of i-th user, be the midamble sequence of i-th user, length be 144 (i.e. b=144, but be not limited thereto), * is convolution;

2) give up before by 16 of a data symbol multi-path jamming chip (that is, l=16, but be not limited thereto), may take out 128 chips (that is, b-l=144-16=128) next, can obtain a _{i, 1}, a _{i, 2}... a _{i, 128};

3), after adding frequency deviation, 128 the reception midamble chip signal obtaining i-th user are: $b_{i,j}=a_{i,j}\&times;e^{-2\mathrm{\&pi;}\&times;{\stackrel{\&OverBar;}{f}}_d\&times;(j-64.5)/1280000},$ Wherein j=1,2 ..., 128, for the frequency deviation value in frequency deviation register;

Step S404, makes other users beyond frequency deviation user to be estimated be interference user, carries out interference simultaneously eliminate all users, obtain the reception midamble sequence estimated for frequency deviation of all users.That is, the signal after eliminating interference is $r^{\&prime;}=r-\underset{k\&Element;K_i}{\mathrm{\&Sigma;}}{b}_k,$ Wherein r is the midamble signal after the multiple user's superpositions received, K _ithe interference user set of i-th user, b _kit is the reconstruction signal of the kth user calculated in previous step;

Step S405, the midamble sequence r ' after being eliminated by interference carries out frequency deviation estimation, obtains instantaneous value f _m;

Step S406, to f _mdo level and smooth, that is, ${\stackrel{\&OverBar;}{f}}_m\left(n\right)={\stackrel{\&OverBar;}{f}}_m(n-1)\&times;(1-p)+f_m\left(n\right)\&times;p,$ Wherein n represents subframe numbers (for subframe in this example, the concept in the moment described in subframe and corresponding embodiment), the smooth value after a upper moment midamble estimates, ${\stackrel{\&OverBar;}{f}}_m\left(0\right)=0;$ P ∈ [0,1] is smoothing factor.In this step, other formula also can be adopted f _mdo level and smooth.

Step S407, by the result of midamble code rough estimate data portion compensates, and carefully estimates accurate instantaneous frequency deviation f by the data after compensating _d;

Step S408, to f _dsmoothing, obtain namely ${\stackrel{\&OverBar;}{f}}_d\left(n\right)={\stackrel{\&OverBar;}{f}}_d(n-1)\&times;(1-p)+f_d\left(n\right)\&times;p.$ Wherein a upper moment with the smooth value after data estimation frequency deviation, ${\stackrel{\&OverBar;}{f}}_d\left(0\right)=0;$ P ∈ [0,1] is smoothing factor.In this step, other formula also can be adopted f _ddo level and smooth.

Step S409, the frequency deviation value upgraded in frequency deviation register is

In this example, the frequency deviation value adopted when interference is eliminated and frequency deviation estimates process is the frequency deviation value in a moment, and owing to have employed parallel processing, therefore, the computational speed of this mode is very fast.

Example 2

This example describes the process carrying out disturbing elimination and frequency deviation estimation to each user's serial.Fig. 5 is the flow chart of interference elimination according to example 2 of the present invention and frequency offset estimation procedure, and as shown in Figure 5, said process mainly comprises the following steps:

Step S501, base station is that each user stores a frequency deviation value, and initial time frequency deviation value is set to 0, in this example, is left in by frequency deviation value in frequency deviation register, but is not limited thereto.

Step S502, base station utilizes reception midamble code to carry out channel estimating, obtains the channel impulse response h of each user respectively;

Step S503, sorts to all users according to watt level order, carries out interference eliminate and frequency deviation estimation according to the power order from big to small of user to user;

Step S504, reconstructs its interference user signal to pending user, the same S403 of detailed process;

Step S505, interference is eliminated, and obtains the reception midamble signal estimated for frequency deviation of user to be estimated $r^{\&prime;}=r-\underset{k\&Element;K}{\mathrm{\&Sigma;}}{b}_k,$ Wherein r is the midamble signal after the multiple user's superpositions received, and K is the interference user set of user to be estimated, b _kit is the reconstruction signal of the kth user calculated in previous step;

Step S506, the midamble sequence after being eliminated by interference carries out frequency deviation estimation, obtains instantaneous value f _m;

Step S507, to f _mdo level and smooth, namely ${\stackrel{\&OverBar;}{f}}_m\left(n\right)={\stackrel{\&OverBar;}{f}}_m(n-1)\&times;(1-p)+f_m\left(n\right)\&times;p,$ Wherein n represents subframe numbers, the smooth value after a upper moment midamble estimates, ${\stackrel{\&OverBar;}{f}}_m\left(0\right)=0;$ P ∈ [0,1] is smoothing factor; In this step, other formula also can be adopted f _mdo level and smooth.

Step S508, by the result of midamble code rough estimate data portion compensates, and carefully estimates accurate instantaneous frequency deviation f by the data after compensating _d;

Step S509, to f _dsmoothing, obtain namely ${\stackrel{\&OverBar;}{f}}_d\left(n\right)={\stackrel{\&OverBar;}{f}}_d(n-1)\&times;(1-p)+f_d\left(n\right)\&times;p.$ Wherein a upper moment with the smooth value after data estimation frequency deviation, ${\stackrel{\&OverBar;}{f}}_d\left(0\right)=0;$ P ∈ [0,1] is smoothing factor; In this step, other formula also can be adopted f _ddo level and smooth.

Step S510, the frequency deviation value upgrading user to be estimated in frequency deviation register is

Step S511, the next user got in sequencing queue is user to be estimated.Forward S504 to.

With example 1 unlike, in this example interference signal reconstruct time, time before interference user comes user to be estimated, can utilize interference user this (namely, present frame) frequency deviation estimated value, the frequency offset estimation accuracy of this mode is higher, but execution speed is slower.

In above embodiment, the process utilizing the signal after eliminating to carry out frequency deviation estimation is also described after interference signal is eliminated, during the result the estimated interference be applied to again is next time eliminated, the method can improve the precision that frequency deviation is estimated and interference is eliminated significantly.Even so, those skilled in the art should understand that, even if what the embodiment of the present invention provided considers that the method that frequency deviation affects uses in conjunction with existing frequency deviation estimating method in the process of interference signal reconstruct, still have and improve the effect that precision is eliminated in interference preferably.

In sum, the multi-user interference cancellation scheme that the embodiment of the present invention provides improves the accuracy of interference signal reconstruct, and then improves the accuracy of follow-up frequency deviation estimation.

Obviously, those skilled in the art should be understood that, above-mentioned of the present invention each module or each step can realize with general calculation element, they can concentrate on single calculation element, or be distributed on network that multiple calculation element forms, alternatively, they can realize with the executable program code of calculation element, thus, they can be stored and be performed by calculation element in the storage device, and in some cases, step shown or described by can performing with the order be different from herein, or they are made into each integrated circuit modules respectively, or the multiple module in them or step are made into single integrated circuit module to realize.Like this, the present invention is not restricted to any specific hardware and software combination.

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (9)

1. a multi-user interference eliminating method, is characterized in that, comprises the following steps:

Base station is according to the frequency deviation value reconstruct midamble interference signal of interference user, wherein, described base station reconstructs described midamble interference signal according to the described frequency deviation value of described interference user and comprises: described base station calculates described midamble interference signal b corresponding to i-th described interference user _i=b _{i, 1}, b _{i, 2}... b _i,jb _{i, b-l}, wherein, the described frequency deviation value of i-th described interference user, a _i,jgiven up the predetermined interference signal by the fractional chips of data symbol multi-path jamming, described predetermined interference signal is the midamble interference signal that have ignored frequency deviation value impact that i-th described interference user is corresponding, j=1,2, b-l, b are the length of midamble sequence, and l is the quantity of described fractional chips, i=1,, N, N are the quantity of described interference user; And,

The midamble interference signal of described reconstruct is eliminated in described base station from the midamble signal received, the midamble signal after the interference that is eliminated.

2. method according to claim 1, is characterized in that, described predetermined interference signal wherein, h _ibe the channel impulse response of i-th described interference user, * calculates convolution, it is the midamble sequence that i-th described interference user is corresponding.

3. method according to claim 1, is characterized in that, the midamble interference signal that described reconstruct is eliminated in described base station from the midamble signal received comprises:

Described base station calculates the midamble signal after eliminating interference wherein, r is the midamble signal that described base station receives.

4. method according to claim 1, it is characterized in that, after the midamble interference signal of described reconstruct is eliminated in described base station from the midamble signal received, also comprise: frequency deviation estimation is carried out to the midamble signal after described elimination interference in described base station, obtains the frequency deviation value of active user at current time.

5. method according to claim 4, is characterized in that, described base station is carried out frequency deviation to the midamble signal after described elimination interference and estimated to comprise:

Frequency deviation estimation is carried out to the midamble signal after described elimination interference in described base station, obtains the instantaneous frequency deviation f of described active user at current time _m, and to f _mthe smoothing frequency deviation rough estimate result obtaining described current time

Described base station adopts the data-signal that described base station receives at described current time is compensated, the data-signal after being compensated;

Frequency deviation estimation is carried out to the data-signal after described compensation in described base station, obtains described active user at the thin estimated result f of the frequency deviation of described current time _d, and to f _dsmoothing, obtain the frequency deviation value of described active user at described current time

6. method according to claim 5, is characterized in that, to f _msmoothingly to comprise: calculate $\stackrel{\&OverBar;}{f_m}={\stackrel{\&OverBar;}{f}}_m^{*}\&times;(1-p)+f_m\&times;p,$ Wherein, it was a upper moment value, and p is smoothing factor, 0=<p<=1.

7. method according to claim 5, is characterized in that, to f _dsmoothingly to comprise: calculate $\stackrel{\&OverBar;}{f_d}={\stackrel{\&OverBar;}{f}}_d^{*}\&times;(1-p)+f_d\&times;p,$ Wherein, it was a upper moment value, and p is smoothing factor, 0=<p<=1.

8. method according to claim 1, is characterized in that, the described frequency deviation value of described interference user was the described frequency deviation value of described interference user in a upper moment, or, for described interference user is at the described frequency deviation value of current time.

9. a base station, is characterized in that, comprising:

Interference reconstructed module, for the frequency deviation value reconstruct midamble interference signal according to interference user, wherein, described interference reconstructed module is for calculating described midamble interference signal b corresponding to i-th described interference user _i=b _{i, 1}, b _{i, 2}... b _i,jb _{i, b-l}, wherein, the described frequency deviation value of i-th described interference user, a _i,jgiven up the predetermined interference signal by the fractional chips of data symbol multi-path jamming, described predetermined interference signal is the midamble interference signal that have ignored frequency deviation value impact that i-th described interference user is corresponding, j=1,2, b-l, b are the length of midamble sequence, and l is the quantity of described fractional chips, i=1,, N, N are the quantity of described interference user;

Interference cancellation module, for eliminating the midamble interference signal of described reconstruct from the midamble signal received, the midamble signal after the interference that is eliminated.