CN1152501C - Doppler small wave base based self-adaptive coherent interference suppression method - Google Patents

Abstract

The present invention relates to a self-adaptive coherent interference suppression method for the suppression of multi-access interference in a direct sequence spread spectrum communication system. In a transmitting side, a pseudo-random sequence is formed by a spread spectrum code of an expected user and is multiplied to a user data signal to be transmitted for forming a base band spread spectrum signal, and the base band spread spectrum signal is transmitted after the wave transformation of the base band spread spectrum signal is carried out by a Doppler small wave base function. In a receiving side, each expected user carries out the wave inverse transformation of self-adaptive matching projecting decomposition of the received signal on the Doppler small wave base function, the received signal is iteratively decomposed for a plurality of times on the Doppler small wave base function, and the multi-access interference is removed according to the comparison of each iterative result and a threshold value. The detection performance of a receiver is enhanced, and the volume of the users of the system is increased.

Description

Self-adaptive coherent interference suppression method based on Doppler small wave base

Technical field

The present invention relates to a kind of wireless communication technology, relate to the multi-access interference suppression technology in a kind of mobile radio system or rather, is a kind of self-adaptive coherent interference suppression method based on Doppler small wave base (Dopplerlet).

Background technology

In code division multiple access (CDMA) wireless communication system, for same base station, because the difference of transmission channel, each terminal use (travelling carriage) can produce multiple access each other and disturb (MAI).Owing to be that cross-correlation exists between each mobile phone users spread-spectrum signal, adopt traditional matched filter receiver detection signal, the influence that multiple access disturbs will make receiver detection performance seriously descend.Therefore, multiple access disturbs (MAI) to be the system for restricting capacity, to influence handoff procedure and power control process, particularly reduces the key factor that receiver detects performance and power system capacity is reduced.

At the intersection of neighbor cell, the receptivity of travelling carriage is had a significant impact from the MAI of adjacent a plurality of base stations.Moreover, Ci Shi MAI also directly influences the handoff procedure and the power control process of travelling carriage.Therefore, if can take certain means to eliminate the influence of (reducing) MAI, will improve receptivity, performance of handoffs, the power control performance of travelling carriage.

Multiuser Detection (Multiuser Detection) technology is the effective technology that overcomes MAI of generally acknowledging at present, but the complexity when its major limitation on using is realization, therefore, to a great extent, multiuser detection generally is just to use under, number is uncertain (or the unknown) situation many at interference user.

In multiuser detection, the best Multiuser Detection method (optimal detection method) that has the eighties creatively to propose by American scholar Verdu, i.e. maximum likelihood method, but because the computation complexity of this method is too high, can't realize in actual applications.Visible [1] S.Verdu of relevant list of references, " Multiuser Detection ", 1998.

At this problem, propose to understand correlation method, least mean-square error (MMSE) method and constraint least energy output (CMOE) method grade optimal algorithm later on again in succession, in addition, the subspace tracking algorithm also can be realized multi-access interference suppression.Wherein, proved that the subspace tracking algorithm has advantages such as digital robustness and convergence rate be very fast, but will use singular value decomposition algorithm in the subspace tracking algorithm, if establishing sampling length is the N point, using the computation complexity of the singular value decomposition algorithm of iteration then is (O (N ²)).Visible [2] the Wang Xiaodong of relevant list of references, and H.Vincent Poor " Blind Multiuser Detection:A Subspace Approach " IEEE Transactions on Information Theory Vol.44.No.2March 1998.

Recently, the projection approximator space track algorithm that researchers proposed further is reduced to computation complexity (O (NK)), and wherein K is a number of users.

Above-mentioned these methods are all at the base station, and in the experiment, we suppose that number of users of mobile terminal is N in the sector, only can be less than or equal to N at the number of users of mobile terminal of the actual activation of synchronization.And at travelling carriage, we can suppose that the signal that arrives simultaneously is 3-5, and this value can obtain from the list message of adjacent cell, so in subspace tracking, without the order of estimated signal subspace.In aforesaid subspace tracking algorithm, only used the signal spread-spectrum sign indicating number of desired user, do not make full use of the data message that existing mobile subscriber terminal (travelling carriage) is had, orthogonal intersection and signal strength information as the received base station of mobile phone users, can not be that the interference of Multiuser Detection inhibition multiple access is made contributions just also, be the Multiuser Detection service with these data messages.Relevant list of references can be referring to [2].

On the other hand, the applicant notices: obtain one group of function after a certain function is through flexible and translation, if the mould square integrable of this group function, then this group function is called wavelet function family, adopt the conversion of small echo to be called wavelet transformation to signal, the small echo exchange has different resolution at the diverse location of different time-frequency planes, is a kind of analytical method of multiresolution, in can be used for signal processing and detecting.Wavelet function can be described as wavelet basis function.The Doppler signal is a big class natural sign, and it can constitute a nonlinear basic function when between the observer of motion and the static wave source relative motion being arranged, and the observer of motion just can experience the nonlinear change of wave source frequency.In mobile communication system, because the high-speed mobile of travelling carriage (observer), when being in the relative motion state between base station (wave source) and the travelling carriage (observer), nonlinear change has just taken place between the primary signal frequency that the signal frequency that travelling carriage (observer) is received and base station (wave source) send, thereby caused the variation of phase place, promptly produced the Doppler frequency displacement.

Summary of the invention

The objective of the invention is to design a kind of self-adaptive coherent interference suppression method based on Doppler small wave base, it is the method that adopts Doppler small wave base to suppress to disturb at code division multiple access (CDMA) mobile communication system, conversion realizes interference mitigation technology based on Doppler small wave base (transform-based) in employing, overcoming multiple access disturbs, fully excavate and also creatively use the religions such as orthogonal intersection of the received base station of existing mobile phone users to it is believed that breath, utilize signal strength signal intensity estimation technique etc., improve the detection performance of useful signal in direct sequency-code division multiple access (DS-CDMA) mobile communication system greatly.

The object of the present invention is achieved like this: a kind of self-adaptive coherent interference suppression method based on Doppler small wave base is characterized in that:

At transmitter side,,, utilize the Doppler small wave base function that each user band spectrum modulation baseband signal is done to close the road transmission again after the wavelet shapes exchange reconstruct respectively by an interference suppression signal exchange sending module of correspondence to the signal of each road after band spectrum modulation;

At receiver side, earlier by each desired user with a corresponding interference suppression signal conversion receiver module, despread-and-demodulation again after doing the wavelet shapes anticommuting that the Adaptive matching projection decomposes on the described Doppler small wave base function still to received signal.

The described Doppler small wave base function that utilizes is done the wavelet shapes conversion to each user band spectrum modulation baseband signal, further comprise: utilize the spreading code of desired user to form a pseudo random sequence, with the user data signal to be sent formation base-band spread-spectrum signal that multiplies each other, with the Doppler small wave base function it is done to launch after the wavelet shapes conversion again.

Described interference suppression signal conversion receiver module, still doing the Adaptive matching projection to received signal on described Doppler small wave base function decomposes, be on based on the Doppler small wave base function, to do the iteration decomposition to received signal, by each iteration threshold, remove one or more interference user signal components.

During described iteration was decomposed, the decomposition coefficient between elementary period was greater than its ability user's decomposition coefficient; During greater than its ability user's decomposition coefficient, continue iterative process at current decomposition coefficient; And when current decomposition coefficient can not be greater than its ability user's decomposition coefficient, stop iterative process.

Described by each iteration threshold removal interference user signal component, be to remove decomposition coefficient greater than the decomposition coefficient between the elementary period of its ability user's decomposition coefficient.

Method of the present invention is at transmitting terminal, utilizes the spreading code of each desired user to form a pseudo random sequence and form base-band spread-spectrum signal earlier, with the Dopplerlet wavelet basis function base-band spread-spectrum signal is made waveform transformation again, and reconstruct transmits; At receiving terminal, received signal is still done the Adaptive matching projection decompose on the Dopplerlet basic function, remove interference signal, promptly curb and remake despread-and-demodulation after multiple access disturbs.Because interference signal is a linear combination of a plurality of subscriber signal spreading codes, no longer is equivalent to the Gaussian noise signal, the present invention adopts Doppler's wavelet transformation to suppress multiple access and disturbs.

It is a kind of method of the Doppler's of realization inverse wavelet transform that the Adaptive matching projection is decomposed, it is launched into received signal the linear combination of a series of basic functions, according to the criterion of projection energy maximum, go out the Doppler small wave base signal of desired user from the basic function centralized detecting that is received.Detailed process is: each desired user is when doing Adaptive matching projection decomposition, and the decomposition coefficient of beginning carries out projection and decomposes greater than its ability user's decomposition coefficient; If, continuing iteration greater than its ability user's decomposition coefficient, decomposes decomposition coefficient; When this relation is false, iteration stopping.The decomposition coefficient of front removes it promptly corresponding to interference signal, can realize multi-access interference suppression.

Method of the present invention, transmit by the processing method reconstruct of adopting the small echo exchange exactly, make the characteristic function that carries Doppler small wave base in transmitting, again in receiver, behind the orthogonal spectrum expansion coded signal that receives the source base station transmission, add the characteristics of signals of handling with the small echo anticommuting, by seeking the optimum value of one group of variable, just can utilize the Doppler small wave base anticommuting to eliminate multiple access and disturb, reach and suppress the purpose that multiple access disturbs when detecting the expectation subscriber signal again fast.

Method of the present invention, utilized the very strong expression ability of Dopplerlet wavelet basis function, fast convergence with Adaptive matching projection decomposition algorithm, this convergence of theory analysis is by exponential quick convergence, usually only need an iteration just can reach the convergence effect 5 times, its computational speed and convergence rate be in the prior art as least-mean-square error algorithm (MMSE) incomparable.

Method of the present invention can utilize mobile phone users (desired user) to receive the orthogonal intersection of base station, and utilizes the signal strength signal intensity estimation technique, realizes the adaptive coherent interference mitigation technology based on Doppler small wave base.

The multiuser detection on the forward link that the present invention proposes, be also creatively to utilize on the basis that these " data messages " do to contribute to Multiuser Detection in abundant " excavations " travelling carriage available data information, disturb the development trend of the multiuser detection of (MAI) technology again in conjunction with current anti-multiple access, simultaneously by the MAI technology of further investigation based on orthogonal intersection and signal strength signal intensity estimation, the Dopplerlet exchange and the Adaptive matching projection algorithm that propose recently in the time frequency analysis have been proposed to utilize, and a kind of technology of multi-access interference suppression fast that works out is the self adaptation Dopplerlet interference mitigation technology of realizing in up link based on time-frequency distributions.

Description of drawings

Fig. 1 is that coherent Doppler disturbs the operation principle schematic block diagram that suppresses detection system:

Fig. 2 is based on the emitting side FB(flow block) of Doppler small wave base disturbance restraining method:

Fig. 3 is based on the receiver side FB(flow block) of Doppler small wave base disturbance restraining method:

Fig. 4 is based on the idiographic flow block diagram of Doppler small wave base disturbance restraining method among Fig. 3.

Embodiment

Further specify method of the present invention below in conjunction with embodiment and accompanying drawing.

Referring to Fig. 1 and in conjunction with referring to Fig. 2, Fig. 3, be example with the direct sequence spread spectrum communication system (DS-CDMA) of pseudo random sequence spread spectrum (PN) sign indicating number, it is general baseband transmission and received communication system.Use s _kThe expression data flow, and form base-band spread-spectrum signal with frequency expansion sequence c (n) back of multiplying each other.During experiment, it is pseudo random sequence that frequency expansion sequence c (n) chooses the Gold sign indicating number.

Transmitter side, 1...k...K the road signal source forms 1...k...K road modulated spread spectrum signal after multiplying each other with separately frequency expansion sequence, 1...k...K road signal after band spectrum modulation is exchanged sending module, with Gauss's Doppler small wave base function (GDL) modulated spread spectrum signal is carried out Gauss Doppler wavelet transformation (GDT) by corresponding 1...k--K interference suppression signal respectively, make transmitting of reconstruct carry the characteristic function of Doppler small wave base, merge the back to transmission channel 11 emissions by mixer 10 again.

Under Rayleigh (Rayleigh) attenuation channel, signal of communication is bearing the selectivity of channel frequency decline that multipath delay causes in communication process, can cause intersymbol interference, in addition, because the Doppler frequency displacement that observer's high-speed mobile of motion causes, be the time selective fading of channel, this because the variation of the information source information that the decline of channel causes is called multiplicative noise.In mobile communication, the actual channel model generally is a rayleigh fading channel, and also there is same case other application scenario, as the motion of radar tracking target, because aerial target high-speed motion often, so Doppler frequency shift is often very big.Therefore, how effectively to estimate channel, realize that coherent interference suppresses, be the research focus that receives much attention always.

Observer in motion is a receiver side, the implementation that coherent interference suppresses is: to the time-division pilot configuration, at first utilize frequency pilot sign that channel is estimated, the interference suppression signal conversion receiver module that the parameter of estimating flows to desired user still utilizes k Gauss's Doppler small wave base function (GDL) to make Gauss Doppler inverse wavelet transform ((GDT) to received signal ^-1), suppress to carry out again after multiple access disturbs the despread-and-demodulation and the bit decision (signal decision and detection) of data.

At receiving terminal, what have that the RAKE receiver of L branch receives is signal from L most powerful path, after the frequency expansion sequence despreading of acknowledge(ment) signal through response, sampled in position corresponding to frequency pilot sign in signal, and by comparing with frequency pilot sign, system's identifying approach identification through relatively more classical obtains pilot channel.At this moment, the channel value that obtains is the channel corresponding with frequency pilot sign, as for utilizing frequency pilot sign to obtain the channel value of data symbol correspondence, many methods are arranged in the prior art, as add channel estimation method of full multi-slot average method, adaptive Gauss interpolation method, decision-feedback and adaptive prediction method, Kalman filter method and joint information etc., all can estimate channel parameter values comparatively accurately.

After estimating channel parameter values, the channel parameter that just can utilize estimation to obtain is realized the coherent demodulation of channel, and the data after the demodulation have just obtained the form of similar Rayleigh channel model through removing error.The present invention utilizes the disturbance restraining method based on the Dopplerlet basic function, in adaptive disturbance suppresses, mainly is to utilize the signal waveform of desired user to remove to extract adaptively the signal of wishing reception.

General interference inhibition and Multiuser Detection are all studied under ideal communication channel, and ideal communication channel promptly transmits and have only the interference of white Gaussian noise by channel the time, and when channel model is Rayleigh (Rayleigh) attenuation channel, the difficulty of research will increase.The explanation of present embodiment elder generation is resonable thinks under the channel to be the implementation of the interference mitigation technology under the additive white Gaussian noise channel, and the coherent interference inhibition technology under Rayleigh (Rayleigh) attenuation channel is described again.

Under additive white Gaussian noise channel, an expectation user received signal is the baseband signal s of base station _k* c (n) adds the interference signal i (k) and the noise item n (k) of other mobile phone users.If random sources data flow (bit) s _kDuration be Ts second, chip duration is Tc second, then can get spreading gain N, N=Ts/Tc.At receiving terminal, carry out despreading with the spreading code of desired user, Shu Chu judgment variables is that the multiple access that desired signal, multiple access subscriber signal and desired user signal cross-correlation cause disturbs and this noise component(s) of band limit for height at last.Because cross-correlation exists between each user's spread-spectrum signal, if adopt traditional matched filter receiver to come detection signal, the influence that multiple access disturbs can make the detection performance of receiver seriously descend.What the present invention proposed is to adopt Doppler's small echo exchange base to overcome the new method that multiple access disturbs.

In mobile communication, because the high-speed mobile of travelling carriage has caused the variation of phase place, i.e. Doppler frequency displacement causes frequency modulation or spread spectrum at random again by the Doppler frequency displacement.Usually, the frequency of establishing static wave source is f ₀, motion observer's movement velocity is v, and the aerial propagation velocity of signal is u, and motion observer and the distance of static wave source on its direction of motion are 1, and the signal frequency f that the observer received that then moves can be obtained by (1) formula:

$f=\frac{u}{u-\frac{v^2(t-t_0)}{\sqrt{l^2+v^2{(t-t_0)}^2}}}{f}_0...\left(1\right)$

T in the formula ₀Be the reference time, t is detection time, as t＜to, f＞f ₀The time, the observer of expression motion is near static wave source, as t＞to, f＜f ₀The time, the observer of expression motion is away from static wave source.By (1) formula as can be known, the Doppler signal of the observer of motion reception can be obtained by formula (2):

d′ _{t0，f0,t,u,v}＝exp｛j2πf(t-t ₀) ²}......(2)

With this Doppler signal normalized Gaussian function is modulated, is just obtained Gauss Doopledet small echo, provide by (3) formula:

$d_{t{0}^{,}f0,\log \left(\mathrm{\Λt}\right),t,u,v\left(t\right)}=\frac{1}{\sqrt{\sqrt{\mathrm{\π}{\mathrm{\Λ}}_t}}}\exp \{-\frac{1}{2}{\left(\frac{{t-t}_0}{{\mathrm{\Λ}}_t}\right)}^2\}$

$\×\exp \{j2\mathrm{\πu}{[u-\frac{v^2\left({t-t}_0\right)}{\sqrt{l^2+v^2{\left({t-t}_0\right)}^2}}]}^{-1}{f}_0\left({t-t}_0\right)......\left(3\right)$

Obviously, describe a Gauss Dopledet needs six parameters, comprising: reference time t ₀, the frequency f of static wave source ₀, wide log (∧ during logarithm _t), the vertical range 1 between observer's direction of motion and static wave source, observer's movement velocity v, the wave source propagation velocity u in transmission medium.

In order to make Doppler small wave base become the complete base in Martin Hilb (Hilbert) space, that is, make Doppler's small echo become general basic function.Make basic function with Doppler's small echo, i.e. the arbitrary square integrable signal of definable S (t) ∈ L ²(R) continuous-wave doppler wavelet transformation is (4) formula:

$\mathrm{GDT}(t,f)=<s\left(t\right),d_{t0,f0,\log \left(\mathrm{\&Lambda;t}\right),t,u,v\left(t\right)}>......\left(4\right)$

Constitute Doppler's function with received signal S (t) with Gauss Doppler small echo inner product in the following formula,, therefore be called continuous Gauss's Doppler-shift because it is the conversion that utilizes Gauss Doppler small echo to obtain.

In conjunction with referring to Fig. 3, Fig. 4, the present invention at first adopts Adaptive matching projection decomposition algorithm (matchingpursuit) to realize Gauss Doppler exchange, use Adaptive Matching Algorithm based on Gauss's Doppler-shift to suppress multiple access and disturb, and can prove based on the Adaptive matching decomposition algorithm of Doppler small wave base function and restrain.

If S ∈ H is a signal to be decomposed, wherein H represents Martin Hilb (Hilbert) space, D=(d _r) _{Re г}Be the basic function collection (storehouse) in H, purpose is to select segment vector to represent S linearly in D, and this expression is to realize by the text projection of S in D.If d _R0∈ D, then a certain signal s can be decomposed into by (5) formula:

$s=|<S,d_{r0}>|d_{r0}+R_s......\left(5\right)$

Wherein＜and S, d _R0Be that S is at d _R0Projection on the direction, R _sBe corresponding residual signals, obviously, d _R0Be orthogonal to R _sBut because optimum＜S, d _R0Fully quadrature be difficult to reach, this is because the basic function among the D is unlimited, in actual computer was handled, we can select a suboptimal solution by (6) formula:

$|<S,d_{r0}>|\&GreaterEqual;\underset{r\&Element;\mathrm{\&Gamma;}}{\mathrm{asup}}|<S,d_r>|......\left(6\right)$

Wherein a is the constant that satisfies 0＜a≤1.

Order $R_s^0=s,$ Suppose to finish m time iteration, then after m+1 iteration, satisfy (7) formula:

$R_s^0=\underset{n=0}{\overset{m}{\mathrm{\&Sigma;}}}<R_s^n,d_m>d_m+R_s^{m+1}......\left(7\right)$

Because R _s ^M+1Be orthogonal to d _Rm, (8) formula is arranged again:

${\left|\right|R_s^m\left|\right|}^2=|<R_s^m,d_{\mathrm{rm}}>{|}^2+{\left|\right|R_s^{m+1}\left|\right|}^2......\left(8\right)$

Therefore:

${\left|\right|R_s^0\left|\right|}^2=\underset{n=0}{\overset{m}{\mathrm{\&Sigma;}}}|<R_s^n,d_{\mathrm{rn}}>{|}^2+{\left|\right|R_s^{m+1}\left|\right|}^2......\left(9\right)$

Disturbance restraining method based on Dopplerlet, mainly be according to received signal the coupling projection algorithm iterative process in, the degree of correlation difference of each signal component is carried out, make c (n) expression spreading code, it is carried out the Dopplerlet inverse transformation, in each iterative process, try to achieve the correlation ratio of best projection coefficient and residual energy by (10) formula, for:

$\stackrel{-}{\mathrm{\&lambda;}}\left(R_c^n\right)=\frac{|<R_c^n,d_{\mathrm{rn}}>|}{\left|\right|R_c^n\left|\right|}......\left(10\right)$

Because c (n) is a pseudo noise code, its degree of coherence is very low, again because interference is a plurality of subscriber signal sums, it is big that its degree of coherence is wanted, therefore the spread-spectrum signal that is received no longer is a pseudo random sequence, and promptly in self adaptation projection matching algorithm, interference signal component has high correlation about Doppurlet, available a spot of high-energy representation in components, and the correlation of desired signal and noise is very weak.Just the interference user signal component can be got rid of by an iteration threshold.If S (n) carries out the Dopplerlet anticommuting to received signal, under the condition of 0≤n＜m, when satisfied (11) formula:

The time, a preceding m coherent structure just belongs to interference, and residual energy as long as find the m value of satisfied (11) formula, just can be eliminated the interference in the received signal with regard to the energy sum of corresponding desired user signal and white noise.Among Fig. 4, the spread-spectrum signal of reception is 1...k...K, is to utilize k Doppler small wave base function to carry out Doppler's inverse transformation at 1...k...K spread-spectrum signal with self adaptation projection decomposition method.Carry out " in the decision range? " process find the process of the m value of satisfied (11) formula exactly, before the m value that does not find satisfied (11) formula, continue iteration, stop iteration during the m value of satisfied until finding (11) formula, in the iteration, for not then do removal processing of the interference of the multiple access in this scope, the process of carrying out " disturb and has suppressed " among the figure is found the solution the difference of (8) formula and (9) formula exactly whether less than the process of a certain preset value (threshold value), and the iterations of maximum should be K.

In the experiment, channel model adopts humorous wave synthesis method, and the average power, time delay, received signal model in each footpath of frequency selective attenuation channel, relevant RAKE receiver structure are all according to the IUT.M.1225 standard setting of International Telecommunication Association.Data rate in the experiment is 64K, and what pseudo random sequence adopted is the GOLD sign indicating number, and length is 63.In Wideband Code Division Multiple Access (WCDMA) (WCDMA) system of the present invention under quick attenuation channel, at first utilize traditional linear interpolation algorithm to estimate channel value, carry out on this basis then suppressing based on the coherent interference of Doppler small wave base based on Doppler small wave base.Experimental result shows that method of the present invention is practicable.Method of the present invention can not only suppress the non-linear distracter of received signal, and suppresses scheme by coherent interference, in rayleigh fading channel, also can effectively suppress to disturb.

Claims (5)

1. self-adaptive coherent interference suppression method based on Doppler small wave base is characterized in that:

At transmitter side,,, utilize the Doppler small wave base function that each user band spectrum modulation baseband signal is done to close the road transmission again after the wavelet shapes exchange reconstruct respectively by an interference suppression signal exchange sending module of correspondence to the signal of each road after band spectrum modulation;

At receiver side, earlier by each desired user with a corresponding interference suppression signal conversion receiver module, despread-and-demodulation again after doing the wavelet shapes anticommuting that the Adaptive matching projection decomposes on the described Doppler small wave base function still to received signal.

2. a kind of self-adaptive coherent interference suppression method according to claim 1 based on Doppler small wave base, it is characterized in that: the described Doppler small wave base function that utilizes is done the wavelet shapes conversion to each user band spectrum modulation baseband signal, further comprise: utilize the spreading code of desired user to form a pseudo random sequence, with the user data signal to be sent formation base-band spread-spectrum signal that multiplies each other, with the Doppler small wave base function it is done to launch after the wavelet shapes conversion again.

3. a kind of self-adaptive coherent interference suppression method according to claim 1 based on Doppler small wave base, it is characterized in that: described interference suppression signal exchange receiver module, still doing the Adaptive matching projection to received signal on described Doppler small wave base function decomposes, be on based on the Doppler small wave base function, to do the iteration decomposition to received signal, by each iteration threshold, remove one or more interference user signal components.

4. a kind of self-adaptive coherent interference suppression method based on Doppler small wave base according to claim 3 is characterized in that: during described iteration was decomposed, the decomposition coefficient between elementary period was greater than its ability user's decomposition coefficient; During greater than its ability user's decomposition coefficient, continue iterative process at current decomposition coefficient; And when current decomposition coefficient can not be greater than its ability user's decomposition coefficient, stop iterative process.

5. a kind of self-adaptive coherent interference suppression method according to claim 3 based on Doppler small wave base, it is characterized in that: described by each iteration threshold removal interference user signal component, be to remove decomposition coefficient greater than the decomposition coefficient between the elementary period of its ability user's decomposition coefficient.

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