CN102694628B - Interference suppression method for multi-user MIMO collaborative relay system - Google Patents

Abstract

The invention discloses an interference suppression method for a multi-user MIMO collaborative relay system, mainly solving the problem that each user has multiple antennas in a common-channel multi-user relay system. The interference suppression method comprises the steps that: a user determines a beamforming vector by adopting a signal space alignment method, and sends out a signal after weighting the signal with the beamforming vector in a multiple-access time slot; a relay constructs a precoding matrix based on an orthogonal projection principle, and amplifies and sends the received signal after precoding; the user receives the signal and suppresses interference signals between user pairs by adopting a decoding vector, and conducts a maximum likelihood detection to obtain the needed signal. According to the invention, a network transmission rate and a resource utilization rate are improved, diversity gains of multiple antennas are achieved, channel fading resisting capability of the system is enhanced, and a bit error ratio is decreased. Further, the interference suppression method of the invention can be applied in a transmission mode under centralized management and control of a wireless ad hoc network and base station, wherein data can be exchanged directly through user-relay-user mode.

Description

Disturbance restraining method based on multiuser MIMO collaboration relay system

Technical field

The invention belongs to communication technical field, relate to signal space alignment schemes, particularly a kind of disturbance restraining method for multiuser MIMO collaboration relay system, can be used for radio communication.

Background technology

In real life, often need to use two-way communication reliably in real time, such as the real-time interactive document between user, video calling and special-purpose supervisory control system etc.Two-way communication requires communication two ends sending and receiving signal simultaneously, due to interval, geographical position or the channel quality that direct transfers severe, the user that expectation realizes two-way communication voluntarily networking realizes reliable communication, at this time can utilize relaying to assist two-way communication.Relaying is generally divided into two kinds of patterns, i.e. decoding forward type DF and amplification forwarding type AF.Decoding forward type relaying is first to carry out to the received signal decoding, if receive correctly, will after the signal recompile receiving, transmit; Amplification forwarding type relaying is to forward after directly amplifying to the received signal.Compare with decoding forward type relaying, amplification forwarding type relaying has lower signal processing delay and complexity, is more suitable for real time bidirectional communication.Cooperative relaying technology is carried out Combined Treatment complete a plurality of node time communication by the multiple signals that receive, can extended coverage range, improve the spectrum efficiency of wireless transmission.In addition, in conjunction with MIMO technique MIMO, can effectively reduce error rate of system, expand power system capacity region, improve systematic function.

Due to the broadcast characteristic of radio communication, the signal that multi-user launches in similar frequency bands simultaneously certainly leads to common-channel interference, and the introducing of MIMO has also increased difficulty and the complexity of anti-interference algorithm.The newest fruits of multi-user's common-channel interference is signal space alignment algorithm, its core concept is design beam forming vector, the less desirable interference signal of receiving node is snapped to same signal subspace, and suppress matrix by interference, desired signal is configured to corresponding orthogonal subspaces, realizes disturbing and suppress.

The patent " a kind of Multithread bidirectional relay transmission method based on amplification forwarding " (number of patent application 201110200566.5, publication No. CN102355291A) of Beijing University of Post & Telecommunication's application.This patent application has mainly proposed a kind of multiple-input and multiple-output bi-directional relaying transmission method based on amplification forwarding, and the step of the method is: relaying carries out a day line options by two users' channel matrix; Then according to the antenna subset of selecting, carry out bi-directional relaying transmission, settling signal is mutual.The deficiency that this patent application exists is: under identical running time-frequency resource, relaying can only be realized two information exchanges between user, can not realize the bidirectional transfer of information that a plurality of users are right, has reduced network transmission speed and power system capacity.

The patent " a kind of network coding transmission method " (number of patent application 201010533192.4, publication No. CN101997647A) of Beijing University of Post & Telecommunication's application.This patent application is mainly the cooperative relaying transmission method that has proposed a kind of network code, the steps include: that relaying carries out respectively network code to signal, broadcast transmission after then the signal after the right network code of different user being superposeed according to a plurality of users that get.The deficiency that this patent application exists is: the method is only applicable to the scene that user configures single antenna, and the scene that configures many antennas for user is inapplicable, thereby can not obtain potential diversity gain, the anti-channel fading ability of system a little less than.

Summary of the invention

The object of the invention is to for above-mentioned the deficiencies in the prior art, propose a kind of disturbance restraining method based on multiuser MIMO collaboration relay system, to improve network transmission speed and resource utilization, obtained the diversity gain of many antennas, the anti-channel fading ability of enhancing system, reduces the error rate.

The basic ideas that realize the object of the invention are that at the first time slot, multiple access access slot user adopts signal space alignment schemes to determine beam forming vector, and will after signal weighting to be sent, send with wave beam formation vector; Relaying obtains pre-coding matrix according to equivalent channel matrix, and the multiple user signals receiving is carried out to precoding processing, and after amplification, at the second time slot, broadcast transmission time slot sends; User receives signal and adopts decoding vector to suppress the interference signal between user couple, then carries out Maximum Likelihood Detection and obtain required signal.Implementation step comprises as follows:

(1) each user determines the combinations of pairs that need to communicate, and according to combinations of pairs, adopts signal space alignment schemes, determines beam forming vector separately, and obtains user to the equivalent channel vector of relaying;

(2) each user modulates signal to be sent separately, obtains modulation signal, and adopts above-mentioned definite beam forming vector after modulation signal weighting, to send at multiple access access slot;

(3) relaying utilizes above-mentioned each user to the equivalent channel vector of relaying, constructs pre-coding matrix P:

3a) by except i user to the right equivalent channel vector of K-1 user form side by side the dimension of N * (K-1) matrix U _i=(u ^{[r, 1]}..., u ^{[r, i-1]}, u ^{[r, i+1]}..., u ^{[r, K]}), wherein N is relay antenna number, K is the number that user is right;

3b) calculate corresponding i the orthogonal intersection cast shadow matrix that user is right wherein I is unit matrix, for U _iassociate matrix;

3c) according to above-mentioned projection matrix structure relaying pre-coding matrix: wherein, for the power normalization factor, || || represent 2 norms of vector;

(4) signal that each user of relay reception sends, and carry out to the received signal amplifying after premultiplication with above-mentioned pre-coding matrix P, then at broadcast transmission time slot, sent;

(5) user disturbs and suppresses and demodulation after detection the retransmit receiving:

5a) user receives the signal that relaying sends, and uses v ^{[i] H}as decoding vector, by following formula, carry out premultiplication to the received signal:

${\hat{y}}^{\left[i\right]}=v^{\left[i\right]H}{y}^{\left[i\right]}$

Suppressed the interference signal between user's group, decoding goes out required signal, wherein, and v ^{[i] H}for beam forming vector v corresponding to user i ^[i]conjugate transpose, y ^[i]the signal receiving for user i, for the reception signal after interference suppresses;

5b) to disturbing the reception signal after suppressing to adopt maximum likelihood method to detect;

5c) to detecting the signal obtaining, carry out demodulation, obtain the required reception signal of user.

The above-mentioned disturbance restraining method based on multiuser MIMO collaboration relay system, wherein the described employing signal space alignment schemes of step (1), determines beam forming vector separately, utilizes following signal space aligned condition to determine:

$\mathrm{span}\left(H^{[r,i]}{v}^{\left[i\right]}\right)=\mathrm{span}\left(H^{[r,i+K]}{v}^{[i+K]}\right)(\∀i=\mathrm{1,2},...,K)$

Wherein, span () represents the space of being opened by matrix column vector, and r represents relaying, and i and i+K represent to need two right users of i user of exchange message, v ^[i]and v ^[i+K]the beam forming vector that represents respectively user i and user i+K, H ^{[r, i]}and H ^{[r, i+K]}be respectively user i and user i+K to the uplink channel transmission matrix of relaying, above-mentioned transmission matrix feeds back to each user after obtaining by relaying.

The above-mentioned disturbance restraining method based on multiuser MIMO collaboration relay system, the user in wherein said step (1), to the equivalent channel vector of relaying, is obtained by following formula:

u ^[r,i]＝H ^[r,i]v ^[i]＝H ^[r,i+K]v ^[i+K]

Wherein, u ^{[r, i]}represent that two users of i user's centering divide the equivalent channel vector that is clipped to relaying.

The above-mentioned disturbance restraining method based on multiuser MIMO collaboration relay system, in wherein said step (1), the realization condition of signal space alignment schemes is, relay antenna number is less than the antenna sum that two of each user's centerings are carried out the user of signal space alignment.

The above-mentioned disturbance restraining method based on multiuser MIMO collaboration relay system, the modulator approach in wherein said step (2) adopts binary phase modulator approach.

The above-mentioned disturbance restraining method based on multiuser MIMO collaboration relay system, the condition that the pre-coding matrix P in wherein said step (3) realizes is that relay antenna number is more than or equal to the number that user is right.

The above-mentioned disturbance restraining method based on multiuser MIMO collaboration relay system, wherein said step 5b) maximum likelihood method in is undertaken by following formula:

${\hat{s}}^{[i+K]}=\arg \underset{s^{[i+K]}}{\min }{|{\hat{y}}^{\left[i\right]}-{\mathrm{\α}}_i\mathrm{\β}{\left(P_i{u}^{[r,i]}\right)}^H{u}^{[r,i]}(s^{\left[i\right]}+s^{[i+K]})|}^2$

Wherein, for user i detects the signal from user i+K obtaining, s ^[i]and s ^[i+K]be respectively the transmitted signal of user i and user i+K, for user i is through disturbing the reception signal after suppressing, P _ifor step 3b) described in i right orthogonal intersection cast shadow matrix of user of correspondence, u ^{[r, i]}for the equivalent channel vector of user i to relaying, α _ifor the right power normalization factor of corresponding i user, β is relaying amplification coefficient, variate-value when arg min represents to make target function get minimum value, () ^hrepresent conjugate transpose operator, || ²represent the modulus of complex number square.

The above-mentioned disturbance restraining method based on multiuser MIMO collaboration relay system, wherein said step 5c) demodulation in adopts and modulates corresponding demodulation mode.

The present invention compared with prior art has the following advantages:

The first, because the present invention has adopted signal space alignment schemes, and utilize orthogonality projection principle to design pre-coding matrix, the user who has suppressed common channel between interference signal, can make a plurality of users that configured many antennas to carry out transfer of data simultaneously, improve resource utilization ratio and network transmission speed.

The second, because user has in the present invention adopted multi-antenna technology, make full use of many antennas and obtained higher diversity gain, improved the reliability of wireless communication system, reduced the error rate.

Three, user-relaying-user that the present invention can be applicable under wireless self-organization network and base station centralized management control directly carries out in the transmission mode of exchanges data.

Accompanying drawing explanation

Fig. 1 is the applicable system model schematic diagram of the present invention;

Fig. 2 is flow chart of the present invention;

Fig. 3 is BER Simulation figure of the present invention.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail.

With reference to Fig. 1, in the applicable system model of the present invention total K user to a relaying, the user that each user communicates by letter to comprising two needs, is respectively user i and user i+K, wherein, i=1,2 ..., K.Each user configured antenna number is M, and the antenna number of link deployment is N.Whole communication process is divided into two time slots, and first time slot is multiple access access slot, and second time slot is broadcast transmission time slot.At multiple access access slot, each user adopts signal space alignment schemes to retransmit, and wherein user i is H to the uplink channel transmission matrix of relaying r ^{[r, i]}; At broadcast transmission time slot, relaying adopts orthogonality projection principle to carry out to the received signal amplifying broadcast after precoding processing, and wherein relaying r is H to the downlink channel transmission matrix of user i ^{[i, r]}.User and relaying all communicate with TDD mode, suppose that transmission channel meets heterogeneite, i.e. H ^{[i, r]}for H ^{[r, i]}associate matrix.By signal space alignment schemes and orthogonality projection principle, obtained the antenna constraints of following user and relaying:

$\left\{\begin{array}{c}2M-N>0\\ N\≥K\end{array}\right.$

According to as above constraints, system can adopt multiple antenna combination, for example: the first combination K=2, M=3, N=2; The second combination K=2, M=2, N=3; The third combines K=3, M=2, N=3 etc., number of users K=2 in the present embodiment, user's antenna number M=2, the antenna number N=3 of relaying.

With reference to Fig. 2, performing step of the present invention is as follows:

Step 1, user determines beam forming vector.

1a) each user determines the combinations of pairs that need to communicate, according to combinations of pairs, adopt signal space alignment schemes, by belonging to same user in signal to be sent, right two paths of signals snaps to same signal subspace, determines beam forming vector separately.

In the embodiment of the present invention, the specific implementation of signal space alignment is carried out according to following formula:

$\mathrm{span}\left(H^{[r,i]}{v}^{\left[i\right]}\right)=\mathrm{span}\left(H^{[r,i+K]}{v}^{[i+K]}\right)(\∀i=\mathrm{1,2},...,K),$

Wherein, span () represents the space of being opened by matrix column vector, and r represents relaying, and i and i+K represent to exchange two right users of i user of signal, H ^{[r, i]}and H ^{[r, i+K]}be respectively user i and user i+K to the uplink channel transmission matrix of relaying, above-mentioned transmission matrix feeds back to each user, v after obtaining by relaying ^[i]and v ^[i+K]the beam forming vector that represents respectively user i and user i+K, above-mentioned beam forming vector is existed, in document A novel signaling on the MIMO Y channel signal pace alignment for network coding, provide the condition that antenna must be satisfied, relay antenna number must be less than the antenna sum that two of each user's centerings are carried out the user of signal space alignment: 2M-N > 0;

1b), after signal space alignment, two users of i user's centering divide the equivalent channel vector that is clipped to relaying to be: u ^{[r, i]}=H ^{[r, i]}v ^[i]=H ^{[r, i+K]}v ^[i+K].

Step 2, user's transmitted signal

Each user is to signal W to be sent separately ^[i]modulate, obtain modulation signal s ^[i], modulator approach adopts binary phase modulation or quaternary phase-modulation or quadrature amplitude modulation, adopts binary phase modulation in the embodiment of the present invention.

At multiple access access slot, the to be sent signal of each user after to modulation adopts step 1a) in this user's beam forming vector v ^[i]be weighted, all users send the signal to be sent after weighting simultaneously.

Step 3, relaying structure pre-coding matrix

Relaying generates the right orthogonal intersection cast shadow matrix of corresponding different user according to equivalent channel vector, more all orthogonal intersection cast shadow matrixs are added and obtain relaying pre-coding matrix after power normalization, take i user to being example, and its precoding constitution step is as follows:

3a) utilize except i user to the right equivalent channel vector u of K-1 user ^{[r, 1]}..., u ^{[r, i-1]}, u ^{[r, i+1]}..., u ^{[r, K]}open into space L, and this forms the dimension of N * (K-1) matrix U side by side by K-1 equivalent channel vector _i=(u ^{[r, 1]}..., u ^{[r, i-1]}, u ^{[r, i+1]}..., u ^{[r, K]}), for making the orthogonal intersection space L of space L ^⊥exist, L ^⊥dimension must be more than or equal to 1, relay antenna number meets N>=K;

3b) by matrix U _igenerating the right orthogonal intersection cast shadow matrix of corresponding i user is wherein I is unit matrix, () ^hrepresent conjugate transpose operator;

Known according to the character of orthogonal intersection cast shadow matrix, P _i=P _i ^h, and for i user to beyond the right equivalent channel vector u of K-1 user ^{[r, 1]}..., u ^{[r, i-1]}, u ^{[r, i+1]}..., u ^{[r, K]}, all have P _iu ^{[r, j]}=0, u ^{[r, j]}represent j the equivalent channel vector that user is right, j=1 ... .K, j ≠ i, and for i the equivalent channel vector u that user is right ^{[r, i]}, have P _iu ^{[r, i]}≠ 0;

3c) all K user is added and obtains P after power normalization corresponding orthogonal intersection cast shadow matrix, be relaying pre-coding matrix:

$P=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}{\mathrm{\α}}_i{P}_i$

Wherein, for the power normalization factor that user is right corresponding to i, wherein || || represent 2 norms of vector.

Step 4, relaying precoding amplification forwarding.

The signal that 4a) each user of relay reception sends:

$y^{\left[r\right]}=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}(H^{[r,i]}{v}^{\left[i\right]}{s}^{\left[i\right]}+H^{[r,i+K]}{v}^{[i+K]}{s}^{[i+K]})+n^{\left[r\right]}$

$=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}\left(u^{[r,i]}(s^{\left[i\right]}+s^{[i+K]})\right)+n^{\left[r\right]},$

Wherein, H ^{[r, i]}and H ^{[r, i+K]}respectively that two users of i user's centering are to the transmission matrix of relaying, v ^[i]and v ^[i+K]the beam forming vector that represents respectively two users of i user's centering, s ^[i]and s ^[i+K]the transmitted signal that represents respectively two users of i user's centering, u ^{[r, i]}two users that represent i user's centering divide the equivalent channel vector that is clipped to relaying, n ^[r]for the multiple Gaussian noise vector of relaying;

4b) relaying carries out premultiplication with above-mentioned pre-coding matrix P to the user's transmitted signal receiving, and according to relaying power constraint, the signal after to precoding amplifies, and obtains relaying signal x to be sent ^[r], and sent when broadcast transmission time slot,

x ^[r]=βPy ^[r]，

Wherein, for relaying amplification coefficient, P _rfor relaying transmitted power, P _nfor relay reception noise power, || || _fthe F norm of representing matrix.

Step 5, user receives signal and decoding detects.

Take user i as example, receive signal processing as follows:

5a) user i receives the signal that relaying sends, and this reception signal indication is:

y ^[i]＝H ^[i，r]x ^[r]+n ^[i,r]

，

＝H ^[r，i]Hx ^[r]+n ^[i,r]

Wherein, x ^[r]for the signal that relaying sends, n ^{[i, r]}for the white complex gaussian noise vector that user receives, H ^{[i, r]}for being relayed to the transmission matrix of user i, H ^{[r, i]}for the transmission matrix of user i to relaying;

5b) user i adopts its beam forming vector v ^[i]conjugate transpose v ^{[i] H}as decoding vector y to received signal ^[i]carry out premultiplication decoding, complete and disturb to suppress, obtain decoded signal and be:

${\hat{y}}^{\left[i\right]}=v^{\left[i\right]H}{y}^{\left[i\right]}$

$=v^{\left[i\right]H}{H}^{[r,i]H}\mathrm{\β}\underset{j=1}{\overset{K}{\mathrm{\Σ}}}{\mathrm{\α}}_j{P}_j{u}^{[r,j]}(s^{\left[j\right]}+s^{[j+K]})+n^{\left[i\right]}$

$={\left(H^{[r,i]}{v}^{\left[i\right]}\right)}^H\mathrm{\β}\underset{j=1}{\overset{K}{\mathrm{\Σ}}}{\mathrm{\α}}_j{P}_j{u}^{[r,j]}(s^{\left[j\right]}+s^{[j+K]})+n^{\left[i\right]},$

$=u^{[r,i]H}\mathrm{\β}\underset{j=1}{\overset{K}{\mathrm{\Σ}}}{\mathrm{\α}}_j{P_j}^H{u}^{[r,j]}(s^{\left[j\right]}+s^{[j+K]})+n^{\left[i\right]}$

$={\mathrm{\α}}_i\mathrm{\β}{\left(P_i{u}^{[r,i]}\right)}^H{u}^{[r,i]}(s^{\left[i\right]}+s^{[i+K]})+\mathrm{\β}\underset{j=1,j\≠i}{\overset{K}{\mathrm{\Σ}}}{\mathrm{\α}}_j{\left(P_j{u}^{[r,i]}\right)}^H{u}^{[r,j]}(s^{\left[j\right]}+s^{[j+K]})+n^{\left[i\right]}$

Wherein, y ^[i]for the reception signal of user i, s ^[i]and s ^[i+K]be respectively the transmitted signal of user i and user i+K, s ^[j]and s ^[j+K]be respectively the transmitted signal of user j and user j+K, P _ifor corresponding i the orthogonal intersection cast shadow matrix that user is right, Ρ _jfor corresponding j the orthogonal intersection cast shadow matrix that user is right, u ^{[r, i]}for the equivalent channel vector of user i to relaying, u ^{[r, j]}for the equivalent channel vector of user j to relaying, v ^[i]for the beam forming vector of user i, α _ifor the right power normalization factor of corresponding i user, α _jfor the right power normalization factor of corresponding j user, β is relaying amplification coefficient, n ^[i]for the integrated noise of user i after decoding, () ^hrepresent conjugate transpose operator.

As can be seen from the above equation, decoded signal by 3 parts, formed, comprise the useful signal α for user i _iβ (P _iu ^{[r, i]}) ^hu ^{[r, i]}(s ^[i]+ s ^[i+K]), interference signal with noise signal n ^[i].

From the character of orthogonal intersection cast shadow matrix, P _ju ^{[r, i]}=0, j ≠ i, i.e. decoded signal in interference signal be 0, therefore, in the reception signal of user i, the right signal of other users can be eliminated the interference of the right signal of i user:

${\hat{y}}^{\left[i\right]}={\mathrm{\α}}_i\mathrm{\β}{\left(P_i{u}^{[r,i]}\right)}^H{u}^{[r,i]}(s^{\left[i\right]}+s^{[i+K]})+n^{\left[i\right]};$

5c) user i by maximum likelihood method to decoded signal detect, obtain the signal that user i+K sends

${\hat{s}}^{[i+K]}=\arg \underset{s^{[i+K]}}{\min }{|{\hat{y}}^{\left[i\right]}-{\mathrm{\α}}_i\mathrm{\β}{\left(P_i{u}^{[r,i]}\right)}^H{u}^{[r,i]}(s^{\left[i\right]}+s^{[i+K]})|}^2,$

Wherein, for user i detects the signal from user i+K obtaining, for the decoded signal of user i, s ^[i]and s ^[i+K]be respectively the transmitted signal of user i and user i+K, P _ifor step 3b) described in i right orthogonal intersection cast shadow matrix of user of correspondence, u ^{[r, i]}for the equivalent channel vector of user i to relaying, α _ifor the right power normalization factor of corresponding i user, β is relaying amplification coefficient, variate-value when arg min represents to make target function get minimum value, || ²represent the modulus of complex number square;

5d) user i is to detecting the signal obtaining carry out demodulation, obtain the required reception signal of user

The demodulation mode that demodulation employing is corresponding with modulation in step 2.In the embodiment of the present invention, demodulation adopts binary phase demodulation mode.

Effect of the present invention can further illustrate by simulation result:

1. simulating scenes and condition

Fig. 1 is the simulating scenes of the inventive method, and wherein user antenna is counted M=2, and relay antenna is counted N=3, user's logarithm K=2, and it is the multiple Gaussian Profile that 0 variance is 1 that each element in transmission matrix is obeyed average.

2. emulation content and simulation result

By the present invention and the existing simulation comparison that carries out the error rate based on single antenna user and network coding transmission method that disturb to arrange, as shown in Figure 3, wherein curve A is existing methodical ber curve to simulation result, and curve B is ber curve of the present invention.Fig. 3 shows, after employing this method, has effectively reduced error rate of system, has improved anti-channel fading ability and the noiseproof feature of system.

Claims (8)

1. the disturbance restraining method based on multiuser MIMO collaboration relay system, comprises that step is as follows:

(1) each user determines the combinations of pairs that need to communicate, and according to combinations of pairs, adopts signal space alignment schemes, determines beam forming vector separately, and obtains user to the equivalent channel vector of relaying;

(2) each user modulates signal to be sent separately, obtains modulation signal, and adopts above-mentioned definite beam forming vector after modulation signal weighting, to send at multiple access access slot;

(3) relaying utilizes above-mentioned each user to the equivalent channel vector of relaying, constructs pre-coding matrix P:

3a) by except i user to the right equivalent channel vector of K-1 user form side by side the dimension of N * (K-1) matrix U _i=(u ^{[r, 1]}..., u ^{[r, i-1]}, u ^{[r, i+1]}..., u ^{[r, K]}), wherein N is relay antenna number, and K is the number that user is right, and r represents relaying;

3b) calculate corresponding i the orthogonal intersection cast shadow matrix that user is right wherein I is unit matrix, for U _iassociate matrix;

3c) according to above-mentioned projection matrix structure relaying pre-coding matrix: wherein, for the power normalization factor, || || represent 2 norms of vector;

(4) signal that each user of relay reception sends, and carry out to the received signal amplifying after premultiplication with above-mentioned pre-coding matrix P, then at broadcast transmission time slot, sent;

(5) user disturbs and suppresses and demodulation after detection the retransmit receiving:

5a) user receives the signal that relaying sends, and uses v ^{[i] H}as decoding vector, by following formula, carry out premultiplication to the received signal:

${\hat{y}}^{\left[i\right]}=v^{\left[i\right]H}{y}^{\left[i\right]}$

Suppressed the interference signal between user's group, decoding goes out required signal, wherein, and v ^{[i] H}for beam forming vector v corresponding to user i ^[i]conjugate transpose, y ^[i]the signal receiving for user i, for the reception signal after interference suppresses;

5b) to disturbing the reception signal after suppressing to adopt maximum likelihood method to detect;

5c) to detecting the signal obtaining, carry out demodulation, obtain the required reception signal of user.

2. the disturbance restraining method based on multiuser MIMO collaboration relay system according to claim 1, the described employing signal space alignment schemes of step (1) wherein, determine beam forming vector separately, utilize following signal space aligned condition to determine:

span(H ^[r,i]v ^[i])＝span(H ^[r,i+K]v ^[i+K])

Wherein, span () represents the space of being opened by matrix column vector, and r represents relaying, and i and i+K represent to need two right users of i user of exchange message, v ^[i]and v ^[i+K]the beam forming vector that represents respectively user i and user i+K, H ^{[r, i]}and H ^{[r, i+K]}be respectively user i and user i+K to the uplink channel transmission matrix of relaying, above-mentioned transmission matrix feeds back to each user after obtaining by relaying.

3. the disturbance restraining method based on multiuser MIMO collaboration relay system according to claim 1, the user in wherein said step (1), to the equivalent channel vector of relaying, is obtained by following formula:

u ^[r,i]＝H ^[r,i]v ^[i]＝H ^[r,i+K]v ^[i+K]

Wherein, u ^{[r, i]}represent that two users of i user's centering divide the equivalent channel vector that is clipped to relaying.

4. the disturbance restraining method based on multiuser MIMO collaboration relay system according to claim 1, in wherein said step (1), the realization condition of signal space alignment schemes is, relay antenna number is less than the antenna sum that two of each user's centerings are carried out the user of signal space alignment.

5. the disturbance restraining method based on multiuser MIMO collaboration relay system according to claim 1, the modulator approach in wherein said step (2) adopts binary phase modulator approach.

6. the disturbance restraining method based on multiuser MIMO collaboration relay system according to claim 1, the condition that the pre-coding matrix P in wherein said step (3) realizes is that relay antenna number is more than or equal to the number that user is right.

7. the maximum likelihood method the disturbance restraining method based on multiuser MIMO collaboration relay system according to claim 1, wherein said step 5b) is undertaken by following formula:

${\hat{s}}^{[i+K]}=\arg \underset{s^{[i+K]}}{\min }{|{\hat{y}}^{\left[i\right]}-{\mathrm{\α}}_i\mathrm{\β}{\left(P_i{u}^{[r,i]}\right)}^H{u}^{[r,i]}(s^{\left[i\right]}+s^{[i+K]})|}^2$

Wherein, for user i detects the information from user i+K obtaining, s ^[i]and s ^[i+K]be respectively the transmission information of user i and user i+K, for user i is through disturbing the reception signal after suppressing, Ρ _ifor step 3b) described in i right orthogonal intersection cast shadow matrix of user of correspondence, u ^{[r, i]}for the equivalent channel vector of user i to relaying, α _ifor the right power normalization factor of corresponding i user, β is relaying amplification coefficient, variate-value when arg min represents to make target function get minimum value, () ^hrepresent conjugate transpose operator, || ²represent the modulus of complex number square.

8. the demodulation the disturbance restraining method based on multiuser MIMO collaboration relay system according to claim 1, wherein said step 5c) adopts and modulates corresponding demodulation mode.