CN102158312A - Signal-space-alignment-based common-channel multi-user interference suppression method - Google Patents

Abstract

The invention discloses a signal-space-alignment-based common-channel multi-user interference suppression method, which mainly aims to solve the problem of common-channel multi-user interference. The method comprises that: in a multiple access stage in a first timeslot, a communication node transmits independent signals to other receiving communication nodes by a collaborative relay node, simultaneously receives signals from the other communication nodes, and performs signal space alignment on the signals expected to be subjected to network coding to reduce the number of independent information streams received by the relay node; and in a broadcasting transmission stage in a second timeslot, the collaborative relay node broadcasts and transmits the network coded signals, and each communication node eliminates interference signals in the broadcast signals by utilizing interface suppression beam forming, and decodes the network coded signals by utilizing own transmitted signals to obtain an estimated value of the signals expected to be received. By the method, the interference suppression technical advantages of the signal space alignment and the network coding are effectively fused, network capacity is increased, and bandwidth utilization rate is increased; and the method can be used for distributed transmission networks.

Description

Common channel multi-user interference inhibition method based on the signal space alignment

Technical field

The invention belongs to the radio network technique field, relate to signal space alignment and network coding technique, particularly the signal space alignment optimizes method that suppresses based on multi-user interference in the multi-user multi-aerial system can be used for radio communication.

Background technology

Node in the wireless network has mobility and portability, makes that the establishment of wireless network is convenient, flexibly, and has obtained general application.The link of wireless network has broadcast characteristic, and promptly the node in the wireless network can be to other a plurality of node broadcasts information, and same, the node in the wireless network also can receive the information from other a plurality of nodes.Because the broadcast characteristic of node, if the interior at one time broadcasting of a plurality of nodes in the network, can in the free space of propagating, mix mutually between a plurality of signals that then a plurality of node broadcasts are gone out, the mixing of signal can cause to produce between the signal and disturb, and the information that causes receiving node to receive is inaccurate maybe can't to receive required information.

The broadcast characteristic of radio transmission medium, the signal that causes similar frequency bands to be launched simultaneously will inevitably produce common-channel interference CCI.The introducing of multi-antenna technology makes that the characteristic of CCI is different from the situation that traditional single-shot list is received SISO under the MIMO MIMO environment, and MIMO has also increased the difficulty and the complexity of anti-interference algorithm greatly when spatial degrees of freedom is provided.The method that tradition is eliminated channel disturbance roughly has two classes: a class is to introduce the orthogonalization channel, for example: TDMA or FDMA; Second class is to introduce coding/decoding technology or multiuser detection.

The newest research results of multi-user's common-channel interference is an interference space alignment algorithm, its core concept is that the design wave beam forms weight vector, the interference signal that receiving node is not expected snaps to same signal subspace, and desired signal is configured to corresponding orthogonal subspaces by interference cancellation matrix, realize disturbing and suppress.This algorithm has solved multi-user interference inhibition problem under the common channel condition, but because interference signal has taken the part signal space, the system that makes can be limited with the degree of freedom; In collaborative wireless network, signal disturbs the performance that has restricted the network code advantage greatly, causes capacity and efficient in the wireless network low.

Summary of the invention

The objective of the invention is to deficiency at above-mentioned prior art, a kind of multi-source signal space alignment method for designing of combined with network coding is provided, utilizes the network code on the multi-source signal space alignment techniques basis, eliminate multi-user interference, improve bandwidth availability ratio, promote network capacity.

Realize that the object of the invention technical thought is: utilize and disturb the alignment principle, in first transmission cycle, the signal alignment of carrying out network code in many communication nodes desired signal is arrived identical signal subspace, the number of the independent information stream that the minimizing via node receives; Utilize the information after collaborative relaying will be deciphered to carry out the network code modulation, and second transmission cycle broadcast transmission; Each communication node receiver is according to the kernel principle, the structure wave beam forms power the interference signal in the broadcast singal is transformed in the desired signal space kernel in the broadcast singal, the signal that the data decoding that sends at first transmission cycle with interference signal in the elimination communication node received signal and utilization receives, obtain the estimated value of desired signal, its concrete steps comprise as follows:

(1) each communication node determines that according to the signal space criterion of aliging transmission wave beam separately forms weight vector:

1a) each communication node sends the multichannel independent information to other nodes simultaneously, and according to whether needs carry out network code at via node, need to determine the signal combination of spatial alignment;

1b) utilize crossing subspace principle, determine the wave beam that can make above-mentioned signal combination snap to the same signal space and form weight vector;

(2) each communication node forms weight vector with above-mentioned definite wave beam and sends multiple signals simultaneously, and via node receives the mixed signal that each node mails to relaying, and noise cancellation signal is mixed and added to this relaying mixed signal for each communication node information after wave beam forms processing;

(3) the reception transmission channel of via node is converted into equivalent independent channel, deciphers receiving mixed signal, obtains the estimated value of spatial alignment signal;

(4) via node carries out physical-layer network coding to the estimated value of above-mentioned spatial alignment signal, and broadcast transmission network code signal;

(5) communication node receives above-mentioned broadcast singal, disturbs and suppresses that wave beam forms and to the decoding of network code, obtain the estimated value of expectation received signal.

5a) according to the kernel principle, interference signal in the broadcast singal is transformed in the desired signal space kernel in the broadcast singal, make interference signal after the conversion be positioned at the orthogonal subspaces of desired signal, to eliminate the interference signal in the communication node received signal, obtain the received signal y of communication node ⁱ, i ∈ 1,2,3} represents the numbering of receiving node:

$y^i=H^{i,r}\left[\begin{array}{ccc}{v}_k^r& v_j^r& v_i^r\end{array}\right]\left[\begin{array}{c}{W}^{i,j}\⊕W^{j,i}\\ W^{i,k}\⊕W^{k,i}\\ W^{j,k}\⊕W^{k,j}\end{array}\right]+n^i$

$=Q^{i,r}\left[\begin{array}{c}{W}^{i,j}\⊕W^{j,i}\\ W^{i,k}\⊕W^{k,i}\end{array}\right]+n^i$

Wherein, Be the equivalent transmission matrix of i communication node, H ^{I, r}The collaborative relaying r of expression is to the Channel Transmission matrix of i communication node, W ^{J, i}Represent that i communication node mails to the signal of j communication node, W ^{I, j}Represent that j communication node mails to the signal of i communication node, W ^{K, i}Represent that i communication node mails to the signal of k communication node, W ^{I, k}Represent that k communication node mails to the signal of i communication node, W ^{K, j}Represent that j communication node mails to the signal of k communication node, W ^{J, k}Represent that k communication node mails to the signal of j communication node, n ⁱThe noise vector of expression communication node i;

5b) to having eliminated the received signal y of interference signal ⁱSignal carries out the decoding of network code, obtains the estimated value of expectation received signal.

The present invention is because the mode that adopts signal space to align is carried out the signal transmission between source node and the destination node, reduced the independent data flow amount that via node receives, reduced and disturbed the requirement that suppresses the relaying number of antennas, thereby reduced the via node decoding complexity; Because the present invention by using physical-layer network coding at via node, finishes the exchange of a plurality of user profile in two time slots, effectively improve the throughput of network simultaneously, saved the timeslot number that the signal transmission takies, improved the system bandwidth utilance; In addition owing to the present invention passes through to adopt the kernel principle at each communication node receiver, interference signal in the broadcast singal is transformed in the desired signal space kernel in the broadcast singal, effectively suppressed the influence of interference signal, improved the decoding performance of network code decoding.

Description of drawings

Fig. 1 is existing multi-user MIMO system K-way trunk channel model schematic diagram;

Fig. 2 is a realization general flow chart of the present invention;

Fig. 3 is the alignment of the multi-source signal space among the present invention schematic diagram;

Fig. 4 is the network code decoded substream journey figure among the present invention.

Embodiment

Below by drawings and Examples, technical scheme of the present invention is described in further detail.

With reference to Fig. 1, in existing multi-user MIMO system K-way trunk channel, K communication node respectively has M antenna, and via node has N antenna, and in the multiple access access MAC stage of first time slot, i communication node sends independent information stream W to via node ⁱ, i ∈ [1, K], and, receive the signal that sends to i communication node by other communication nodes by via node in the broadcast transmission BC stage of second time slot

J ∈ [1, K], j ≠ i; In a certain moment, information may exchange between all communication nodes.

Technical scheme of the present invention is used the described prior wireless network of Fig. 1, but different with method for transmitting signals in the prior art is, the signal that needs in the embodiment of the invention to carry out network code carries out the signal space alignment, what via node received is the signal that process is mixed, by the signal space alignment techniques, via node carries out separating treatment to the mixed signal that receives, and carries out behind the network code broadcast transmission to all nodes, as shown in Figure 2 again.

With reference to Fig. 2, specific implementation of the present invention comprises:

Step 1: each source node determines that according to the signal space criterion of aliging transmission wave beam separately forms weight vector.

Suppose to exist communication node 1, communication node 2, communication node 3 and collaborative relaying, with numbering 1,2,3, r represents communication node 1, communication node 2, communication node 3 and collaborative relaying respectively, all might communicate by letter simultaneously between communication node and communication node; Relaying has N=3 root antenna, and other communication nodes have M=2 root antenna; Each communication node sends signal to other nodes simultaneously, via node will receive 6 independent information streams, for the via node that 3 antennas are only arranged, therefore can't decipher these information flow vectors, will design wave beam and form power and make that 3 communication nodes are collaborative and send 6 independent information to flow to the degree of freedom be in 3 the signal space.Form temporary at the design wave beam, the signal alignment that allows expectation carry out network code arrives identical signal space, and via node just can obtain 3 independent information streams from 6 independent signal vectors, implementation step:

1a) each communication node sends the multichannel independent information to other nodes simultaneously, and according to whether needs carry out network code at via node, need to determine the signal combination of spatial alignment;

1b) utilize crossing subspace principle, determine the wave beam that can make above-mentioned signal combination snap to the same signal space and form weight vector, promptly utilize following spatial alignment condition to determine:

span(H ^r，jv ^i，j)＝span(H ^r，iv ^j，i)；

Wherein, H ^{R, i}Represent the Channel Transmission matrix of i communication node to collaborative relaying r,

H ^{R, j}Represent the Channel Transmission matrix of j communication node to collaborative relaying r,

v ^{J, i}Represent that i communication node mails to the wave beam formation weight vector of the signal demand of j communication node,

v ^{I, j}Represent that j communication node mails to the wave beam formation weight vector of the signal demand of i communication node, i, j ∈ 1,2,3},

The space that span (X) expression is made of the column vector of any matrix X.

Step 2: each communication node forms weight vector with above-mentioned definite wave beam and sends multiple signals simultaneously, via node receives the mixed signal that each node mails to relaying, and noise cancellation signal is mixed and added to this relaying mixed signal for each communication node information after wave beam forms processing.

With reference to Fig. 3, the wave beam that step 1 is determined forms power and is loaded into respectively on the multiple signals of transmission, and the signal of each communication node after with weighting mails to via node simultaneously, and via node receives the mixed signal that each node mails to relaying and is:

$y^r=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}{H}^{r,i}(v^{j,i}{W}^{j,i}+v^{k,i}{W}^{k,i})+n^r,i,j,k\∈\left\{\mathrm{1,2,3}\right\},i\≠j\≠k$

Wherein, W ^{J, i}Represent that i communication node mails to the signal of j communication node, W ^{K, i}Represent that i communication node mails to the signal of k communication node, n ^rThe noise vector of expression relaying.

Step 3: the reception transmission channel of via node is converted into equivalent independent channel, deciphers receiving mixed signal, obtains the estimated value of spatial alignment signal.

3a) according to network code signal space aligned condition, obtain following signal space alignment equation:

$H^{r,i}{v}^{j,i}=H^{r,j}{v}^{i,j}=u_g^r,$ I, j ∈ 1,2,3} and i ≠ j, g=1,2,3

Wherein:

Represent the equivalent transmission matrix between i communication node and j communication node, the numbering that the g order of representation increases progressively;

3b) via node carries out signal transformation to the mixed signal that receives, and the equivalent signal that obtains after signal space aligns according to signal space alignment equation is:

$y^r=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}{H}^{r,i}(v^{j,i}{W}^{j,i}+v^{k,i}{W}^{k,i})+n^r,$ i，j，k∈{1，2，3}，i≠j≠k

$=\left[\begin{array}{ccc}{u}_1^r& u_2^r& u_3^{\mathrm{<figure-callout\; id="1"\; label="r\; W"\; filenames="HDA0000050995440000032.png"\; state="\{\{state\}\}">r</figure-callout>}}& \\ \end{array},\right]\left[\begin{array}{c}{W}^{}\end{array}\right]\left[\begin{array}{c}{}^{\mathrm{1,2}}+W^{\mathrm{2,1}}\\ {\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="HDA0000050995440000032.png"\; state="\{\{state\}\}">W</figure-callout>}}^{\mathrm{1,3}}+W^{\mathrm{3,1}}\\ W^{\mathrm{2,3}}+W^{\mathrm{3,2}}\end{array}\right]+n^r$

$=U^r{W}^r+n^r$

Wherein, U ^rExpression equivalent channel transmission matrix;

If 3 column vectors

With

Linear correlation, the subspace one that then some column vectors are opened are positioned the signal that subspace that two other column vector opens generates and intersect in the subspace, promptly

I, j, k ∈ 1,2,3}, i ≠ j ≠ k.Because H ^{R, 1}, H ^{R, 2}And H ^{R, 3}It is independent continuous distribution, each transmission channel matrix is by the three dimensions plane difference of its column vector generation, therefore to be positioned at the probability on two other three dimensions plane that intersecting lens constitutes be zero to the intersecting lens on any two three dimensions planes, can obtain as drawing a conclusion:

Pr[det(U ^r)＝0]＝0

Wherein, Pr () expression condition is set up probability; U ^rBe nonsingular square matrix, 3 column vectors

With

Linear independent, collaborative relaying utilizes the ZF decoding algorithm, obtains decoded signal: W respectively ^1,2+ W ^2,1, W ^1,3+ W ^3,1, W ^2,3+ W ^3,2

Step 4: via node carries out physical-layer network coding to the estimated value of above-mentioned spatial alignment signal, and broadcast transmission network code signal.

In the broadcast transmission stage of second time slot, the decoded signal W that via node obtains step 3 ^1,2+ W ^2,1, W ^1,3+ W ^3,1, W ^2,3+ W ^3,2Carry out physical-layer network coding, obtain

Wherein

The expression xor operation, and to all communication node broadcast transmission network code information, the received signal y of communication node i ⁱ, i ∈ 1,2,3} represents the numbering of receiving node:

$y^i=H^{i,r}\left[\begin{array}{ccc}{v}_k^r& v_j^r& v_i^r\end{array}\right]\left[\begin{array}{c}{W}^{i,j}\&CirclePlus;W^{j,i}\\ W^{i,k}\&CirclePlus;W^{k,i}\\ W^{j,k}\&CirclePlus;W^{k,j}\end{array}\right]+n^i$

Wherein, H ^{I, r}The collaborative relaying r of expression is to the Channel Transmission matrix of i communication node, W ^{J, i}Represent that i communication node mails to the signal of j communication node, W ^{I, j}Represent that j communication node mails to the signal of i communication node, W ^{K, i}Represent that i communication node mails to the signal of k communication node, W ^{I, k}Represent that k communication node mails to the signal of i communication node, W ^{K, j}Represent that j communication node mails to the signal of k communication node, W ^{J, k}Represent that k communication node mails to the signal of j communication node, n ⁱThe noise vector of expression communication node i, j, k ∈ 1,2,3}, i ≠ j ≠ k.

Step 5: communication node receives above-mentioned broadcast singal, disturbs and suppresses wave beam formation, filtering interference signals.

5a) in the broadcast singal that receives of communication node except the expectation received signal, also include interference signal, interference signal produces serious the interference to the decoding accuracy, influence the decoding performance of system, therefore must the elimination interference signal; The method that suppresses interference signal is according to the kernel principle, the interference signal in the broadcast singal is transformed in the kernel of expectation signal space in the broadcast singal, and implementation step is as follows:

Obtain interference by following formula and suppress wave beam formation weight vector:

$v_i^r\&Subset;\mathrm{null}\left(H^{i,r}\right)$

Wherein, the kernel of any matrix X of null (X) expression,

The interference of representing i communication node suppresses wave beam formation weight vector, H ^{I, r}Expression via node r is to the Channel Transmission matrix of i communication node;

5b) utilize above-mentioned interference to suppress wave beam and form weight vector, construct the interference signal that i communication node receives

Equivalent transmission channel be

H wherein ^{I, r}The Channel Transmission matrix of relaying r to i communication node worked in coordination with in expression,

It is the Channel Transmission matrix H ^{I, r}Kernel, be about to interference signal in the broadcast singal and transform in the desired signal space kernel in the broadcast singal, the equivalent received signals of i communication node is:

$y^i=H^{i,r}\left[\begin{array}{ccc}{v}_k^r& v_j^r& v_i^r\end{array}\right]\left[\begin{array}{c}{W}^{i,j}\&CirclePlus;W^{j,i}\\ W^{i,k}\&CirclePlus;W^{k,i}\\ W^{j,k}\&CirclePlus;W^{k,j}\end{array}\right]+n^i$

$=Q^{i,r}\left[\begin{array}{c}{W}^{i,j}\&CirclePlus;W^{j,i}\\ W^{i,k}\&CirclePlus;W^{k,i}\end{array}\right]+n^i$

Wherein,

It is the equivalent transmission matrix of i communication node.

Step 6: to the above-mentioned received signal y that has eliminated interference signal ⁱSignal carries out the decoding of network code, obtains the estimated value of expectation received signal.

With reference to Fig. 4, being implemented as follows of this step:

6a) wave beam forms weight vector With

Between linear independent, use the ZF decoding algorithm, obtain the decoded signal of i communication node;

6b) utilize the signal and the above-mentioned decoded signal that self send to carry out the decoded operation of network code, obtain the expectation received signal, its formula is as follows:

${\hat{W}}^{i,j}=(W^{i,j}\&CirclePlus;W^{j,i})\&CirclePlus;W^{j,i}$

${\hat{W}}^{i,k}=(W^{i,k}\&CirclePlus;W^{k,i})\&CirclePlus;W^{k,i}$

Wherein, Represent that j communication node mails to the estimated value of i communication node signal,

Represent that k communication node mails to the estimated value of i communication node signal, W ^{J, i}Represent that i communication node mails to the signal of j communication node, W ^{I, j}Represent that j communication node mails to the signal of i communication node, W ^{K, j}Represent that j communication node mails to the signal of k communication node, W ^{J, k}Represent that k communication node mails to the signal of j communication node.

Above execution mode only is used to illustrate the present invention; and be not restriction of the present invention; the those of ordinary skill in relevant technologies field; under the situation that does not break away from the spirit and scope of the present invention; can also make various variations and modification; therefore all technical schemes that are equal to also belong to category of the present invention, and scope of patent protection of the present invention should be defined by the claims.

Claims (5)

1. the common channel multi-user interference inhibition method based on the signal space alignment comprises the steps:

(1) each communication node determines that according to the signal space criterion of aliging transmission wave beam separately forms weight vector:

1a) each communication node sends the multichannel independent information to other nodes simultaneously, and according to whether needs carry out network code at via node, need to determine the signal combination of spatial alignment;

1b) utilize crossing subspace principle, determine the wave beam that can make above-mentioned signal combination snap to the same signal space and form weight vector;

(2) each communication node forms weight vector with above-mentioned definite wave beam and sends multiple signals simultaneously, and via node receives the mixed signal that each node mails to relaying, and noise cancellation signal is mixed and added to this relaying mixed signal for each communication node information after wave beam forms processing;

(3) the reception transmission channel of via node is converted into equivalent independent channel, deciphers receiving mixed signal, obtains the estimated value of spatial alignment signal;

(4) via node carries out physical-layer network coding to the estimated value of above-mentioned spatial alignment signal, and broadcast transmission network code signal;

(5) communication node receives above-mentioned broadcast singal, disturbs and suppresses that wave beam forms and to the decoding of network code, obtain the estimated value of expectation received signal.

5a) according to the kernel principle, interference signal in the broadcast singal is transformed in the desired signal space kernel in the broadcast singal, make interference signal after the conversion be positioned at the orthogonal subspaces of desired signal, to eliminate the interference signal in the communication node received signal, obtain the received signal y of i communication node ⁱ, i ∈ 1,2,3} represents the numbering of receiving node:

$y^i=H^{i,r}\left[\begin{array}{ccc}{v}_k^r& v_j^r& v_i^r\end{array}\right]\left[\begin{array}{c}{W}^{i,j}\&CirclePlus;W^{j,i}\\ W^{i,k}\&CirclePlus;W^{k,i}\\ W^{j,k}\&CirclePlus;W^{k,j}\end{array}\right]+n^i$

$=Q^{i,r}\left[\begin{array}{c}{W}^{i,j}\&CirclePlus;W^{j,i}\\ W^{i,k}\&CirclePlus;W^{k,i}\end{array}\right]+n^i$

Wherein,

Be the equivalent transmission matrix of i communication node, H ^{I, r}The collaborative relaying r of expression is to the Channel Transmission matrix of i communication node, W ^{J, i}Represent that i communication node mails to the signal of j communication node, W ^{I, j}Represent that j communication node mails to the signal of i communication node, W ^{K, i}Represent that i communication node mails to the signal of k communication node, W ^{I, k}Represent that k communication node mails to the signal of i communication node, W ^{K, j}Represent that j communication node mails to the signal of k communication node, W ^{J, k}Represent that k communication node mails to the signal of j communication node, n ⁱThe noise vector of expression communication node i;

5b) to having eliminated the received signal y of interference signal ⁱSignal carries out the decoding of network code, obtains the estimated value of expectation received signal.

2. channel multi-user interference inhibition method altogether according to claim 1, step 1b wherein) the subspace principle is intersected in described utilization, determine the wave beam that can make above-mentioned signal combination snap to the same signal space and form weight vector, utilize following spatial alignment condition to determine:

span(H ^r，jv ^i，j)＝span(H ^r，iv ^j，i)

Wherein, H ^{R, i}Represent the Channel Transmission matrix of i communication node to collaborative relaying r,

H ^{R, j}Represent the Channel Transmission matrix of j communication node to collaborative relaying r,

v ^{J, i}Represent that i communication node mails to the wave beam formation weight vector of the signal demand of j communication node,

v ^{I, j}Represent that j communication node mails to the wave beam formation weight vector of the signal demand of i communication node, i, j ∈ 1,2,3},

The space that the column vector of any matrix X of span (X) expression constitutes.

3. channel multi-user interference inhibition method, wherein being achieved as follows of step 3 altogether according to claim 1 and 2:

3a) according to network code signal space aligned condition, obtain following signal space alignment equation:

$H^{r,i}{v}^{j,i}=H^{r,j}{v}^{i,j}=u_g^r,$ I, j ∈ 1,2,3} and i ≠ j, g=1,2,3

Wherein: H ^{R, i}Represent the Channel Transmission matrix of i communication node, v to collaborative relaying r ^{J, i}Represent that i communication node mails to the wave beam formation weight vector of the signal demand of j communication node, Represent the equivalent transmission matrix between i communication node and j communication node, the numbering that the g order of representation increases progressively;

3b) via node carries out signal transformation to the received signal, and the equivalent signal that obtains after signal space aligns according to signal space alignment equation is:

$y^r=\underset{i=1}{\overset{3}{\mathrm{\&Sigma;}}}{H}^{r,i}(v^{j,i}{W}^{j,i}+v^{k,i}{W}^{k,i})+n^r,i,j,k\&Element;\left\{\mathrm{1,2,3}\right\},i\&NotEqual;j\&NotEqual;k$

$=\left[\begin{array}{ccc}{u}_1^r& u_2^r& u_3^r\end{array}\right]\left[\begin{array}{c}{W}^{\mathrm{1,2}}+W^{\mathrm{2,1}}\\ W^{\mathrm{1,3}}+W^{\mathrm{3,1}}\\ W^{\mathrm{2,3}}+W^{\mathrm{3,2}}\end{array}\right]+n^r$

$=U^r{W}^r+n^r$

Wherein, W ^{J, i}Represent that i communication node mails to the signal of j communication node, W ^{K, i}Represent that i communication node mails to the signal of k communication node, n ^rThe noise vector of expression relaying, U ^rExpression equivalent channel transmission matrix is a nonsingular square matrix; Because 3 column vectors

With

Linear independent, collaborative relaying utilizes the ZF decoding algorithm, obtains decoded signal: W respectively ^1,2+ W ^2,1, W ^1,3+ W ^3,1, W ^2,3+ W ^3,2

3c) collaborative relaying carries out the physical-layer network coding modulation with decoded signal, obtains code signal:

And at second all code signal of time slot broadcast transmission, wherein

The expression xor operation.

4. altogether channel multi-user interference inhibition method, wherein step 5a according to claim 1) described according to the kernel principle, the interference signal in the broadcast singal is transformed in the desired signal space kernel in the broadcast singal, carry out as follows:

4a) obtain interference and suppress wave beam formation weight vector by following formula:

$v_i^r\&Subset;\mathrm{null}\left(H^{i,r}\right)$

Wherein, the kernel of any matrix X of null (X) expression,

The interference of representing i communication node suppresses wave beam formation weight vector, H ^{I, r}Expression via node r is to the Channel Transmission matrix of i communication node;

4b) utilize above-mentioned interference to suppress wave beam and form weight vector, construct the interference signal that i communication node receives

Equivalent transmission channel be

H wherein ^{I, r}The Channel Transmission matrix of relaying r to i communication node worked in coordination with in expression,

It is the Channel Transmission matrix H ^{I, r}Kernel, be about to interference signal in the broadcast singal and transform in the desired signal space kernel in the broadcast singal.

5. channel multi-user interference inhibition method altogether according to claim 1, step 5b wherein) the described decoding of the broadcast singal of having eliminated interference signal being carried out network code, be to carry out xor operation with the signal and the received signal that self send, obtain the expectation received signal, its formula is as follows:

${\hat{W}}^{i,j}=(W^{i,j}\&CirclePlus;W^{j,i})\&CirclePlus;W^{j,i}$

${\hat{W}}^{i,k}=(W^{i,k}\&CirclePlus;W^{k,i})\&CirclePlus;W^{k,i}$

Wherein,

Represent that j communication node mails to the estimated value of i communication node signal,

Represent that k communication node mails to the estimated value of i communication node signal, W ^{J, i}Represent that i communication node mails to the signal of j communication node, W ^{I, j}Represent that j communication node mails to the signal of i communication node, W ^{K, j}Represent that j communication node mails to the signal of k communication node, W ^{J, k}Represent that k communication node mails to the signal of j communication node.

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