CN102571279A - Combined signal processing method for source end and relay end in bidirectional relay system - Google Patents

Abstract

A combined signal processing method for a source end and a relay end in a bidirectional relay system comprises the following steps: the source end emits a training sequence to a relay, and the relay performs backward channel estimation to obtain an estimation channel between the source end and the relay; the relay emits a training sequence to the source end, and the source end performs forward channel estimation to obtain an estimation channel between the relay and a user; the source end feed forward channel information back to the relay, the relay performs iterative computation to source end nonlinear pre-coding matrixes, relay linear pre-coding matrixes and source end receiving equalization matrixes; the relay feeds the information of the source end back to the source end; emitting signals are subjected to nonlinear pre-treatment through the source end and then emitted to the relay; the signals received by the relay are subjected to linear pre-treatment through the relay and then broadcasted to the source end; and the source end detects the received signals to obtain information required to be transmitted therebetween. According to the invention, the bidirectional relay information transmission mode is adopted to improve the channel capacity, and the nonlinear signal processing method is adopted at the source end, so that the bit error rate performance of the system is improved.

Description

The united signal processing method of source end and relay in the two-way relay system

Technical field

What the present invention relates to is a kind of method of wireless communication field, specifically is the united signal processing method of source end and relay in a kind of two-way relay system.

Background technology

Relaying technique in the GSM; Can enlarge coverage, the raising power system capacity of network effectively; By 3GPP (3rd Generation Partnership Project; The 3G (Third Generation) Moblie partner program) LTE-A (Long Term Evolation-Advanced, Long Term Evolution-senior) standard is adopted.Trunking scheme mainly contains DF (Decode-and-Forward, decoding is transmitted), AF (Amplify-and-Forward amplifies and transmits) etc. at present.Wherein the AF mode is owing to realization is simple, low complex degree has obtained using widely.Traditional relay system will realize that the information between two users passes mutually, needs 4 time slots.And two-way relay system realizes that mutual biography of information only needs 2 time slots between two users, therefore, and the power system capacity that adopts two-way relay system to double.In addition, a plurality of antennas can be installed in source end and relay, further improve systematic function in conjunction with MIMO (Multiple-Input Multiple-Output, multiple-input and multiple-output) technology.In order to give full play to advantages such as the technological branch collection of MIMO, spatial reuse, need the signal processing method of further design source end and relay.The linear signal processing method has obtained using widely because its realization is simple, but in contrast to this, adopts the nonlinear properties processing method but can obtain better system performance.

Through existing literature search is found, Ronghong Mo Yong Huat Chew, " MMSE-Based Joint Source and Relay Precoding Design for Amplify-and-Forward MIMO Relay Networks; " IEEE Trans.Wireless Commun., vol.8, no.9; Pp.4668-4676,2009 (the joint source end and the relaying code Design of MMSE criterion " in the AFMIMO relay systems based on "); End adopts this article in the source is the linear signal processing mode; Compare with the nonlinear properties processing mode, it has lower complexity, but has also brought the systems loss of energy.

Find Fan-Shuo Tseng, Min-Yao Chang again through retrieval; Wen-Rong Wu, " Joint Tomlinson-Harashima Source and Linear Relay Precoders Design in Amplify-and-Forward MIMO Relay System via MMSE Criterion, " IEEE transaction on vehicular technology.vol.60; No.4, MAY 2011 (" end precoding of associating THP source and relay linear predictive coding based on the MMSE criterion in the AF MIMO relay system design ", IEEE vehicle technology periodical; The 60th phase; The 4th volume, 2011.03), this article is considered AF MIMO relaying scene; Base station and relaying adopt THP precoding and linear predictive coding respectively, and are optimization aim with the MSE minimum of system.Realize transinformation between two users, if adopt traditional relay system to need 4 time slots, and if adopt two-way relay system, then only need 2 time slots thereby the throughput that can double.

Also find through retrieval, Rui Wang Meixia Tao, " Joint Source and Relay Precoding Designs for MIMO Two-wWay Relay Systems; " IEEE ICC, 2011 (" joint source end in the two-way relay system of MIMO and relaying precoding design ", IEEE international communication conferences; 2011), the signal processing of this article co-design source end and relaying is with the mean square error of minimized detection signal; But should technology end adopts in the source is linear signal processing method; Compare with adopting the nonlinear properties processing method, realize simply, but brought systemic loss of energies such as mean square error and bit error rate.

Summary of the invention

The objective of the invention is to overcome the above-mentioned deficiency of prior art, source end and relay signal processing method in a kind of two-way relay system are provided.The present invention is according to MMSE (Minimum Mean Squared Error; Least mean-square error) criterion; Co-design source terminal type non-linear and relay linear information processing method, this method has made full use of the advantage of nonlinear properties processing methods, can effectively improve the bit error rate performance of system.

The present invention realizes through following technical scheme, the present invention includes following steps:

The first step, source end 1 is to repeat transmitted training sequence S ₁, relaying is according to the signal X that receives ₁Carry out the back to channel estimating, obtain the back of source end 1 and relay well to channel H ₁, source end 2 is to repeat transmitted training sequence S simultaneously ₂, relaying is according to the signal X that receives ₂Carry out the back to channel estimating, obtain the back of source end 2 and relay well to channel H ₂

In second step, relaying is simultaneously to source end 1 and source end 2 transmitting training sequence S ₃, source end 1 is according to the signal X that receives ₃Carry out forward channel and estimate, obtain the forward channel G of 1 at relaying and source end ₁, source end 2 is according to the signal X that receives ₄Carry out forward channel and estimate, obtain the back of 2 at relaying and source end to channel G ₂

In the 3rd step, source end 1 and source end 2 are with the forward channel information G that estimates to obtain ₁And G ₂Feed back to relaying.Relaying is according to the emission pre-coding matrix C of all channel information iterative computation source ends 1 ₁, F ₁, the emission pre-coding matrix C of source end 2 ₂, F ₂, relaying pre-coding matrix F _rWith the balanced matrix W of the reception of source end 1 ₁, the balanced matrix W of the reception of source end 2 ₂

In the 4th step, relaying is with the source end that calculates 1 emission pre-coding matrix C ₁, F ₁With the balanced matrix W of reception ₁Feed back to source end 1, with source end 2 emission pre-coding matrix C ₂, F ₂With the balanced matrix W of reception ₂Feed back to source end 2, simultaneously with channel information H ₁Feed back to source end 1, with H ₂Feed back to source end 2;

The 5th step, 1 pair of preparatory s emission signal s of source end ₁Carry out preliminary treatment, obtain the x that transmits ₁, and with this signal x ₁Be transmitted to relaying, simultaneously 2 pairs of preparatory s emission signal s of source end ₂Carry out preliminary treatment, obtain the x that transmits ₂, and with this signal x ₂Be transmitted to relaying;

In the 6th step, relaying is y to the received signal _rCarry out linear process, obtain signal

And will

Be broadcast to source end 1 and source end 2;

In the 7th step, source end 1 is y to the received signal ₁Detect processing, obtain signal

Again through with step 5 in identical modular arithmetic obtain signal Simultaneously, source end 2 y to the received signal ₂Detect processing, obtain signal

Again through with step 5 in identical modular arithmetic obtain signal

Back in the said first step to the channel estimation process method is:

${\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">H</figure-callout>}}_1=\sqrt{\frac{{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">M</figure-callout>}}_1}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}1}}}{X}_1{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">S</figure-callout>}}_1^{*}{(\frac{{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">M</figure-callout>}}_1}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}1}}{\mathrm{<figure-callout\; id="1"\; label="I\; M"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">I</figure-callout>}}_{M_{}}+S_1{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">S</figure-callout>}}_1^{*})}^{-1}$

$H_2=\sqrt{\frac{M_2}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}2}}}{X}_2{S}_2^{*}{(\frac{M_2}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}2}}{I}_{M_2}+S_2{S}_2^{*})}^{-1}$

Wherein: M ₁Be the antenna number of source end 1, M ₂Be the antenna number of source end 2, ρ _{τ 1}Be training sequence S ₁Signal to noise ratio, ρ _{τ 2}Be training sequence S ₂Signal to noise ratio,

T _{τ 1}Be the length of the training sequence of source end 1 emission,

T _{τ 2}Be the length of the training sequence of source end 2 emissions,

With

Be the signal that relaying receives, N is the antenna number of relaying,

Be respectively M ₁* M ₁And M ₂* M ₂Unit matrix.

Forward channel estimating processing method in said second step is:

${\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">G</figure-callout>}}_1=\sqrt{\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}}{(\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}{I}_N+S_3{S}_3^{*})}^{-1}{S}_3{X}_3^{*}$

$G_2=\sqrt{\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}}{(\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}{I}_N+S_3{S}_3^{*})}^{-1}{S}_3{X}_4^{*}$

Wherein: N is the antenna number of relaying, ρ _{τ 3}Be training sequence S ₃Signal to noise ratio,

T _{τ 3}Be the length of the training sequence of repeat transmitted,

With Be respectively the signal that source end 1 and source end 2 are received, I _NUnit matrix for N * N.

Iterative calculation method in said the 3rd step is:

Iteration one: suppose C ₁, F ₁, C ₂, F ₂, F _rKnown, the balanced matrix W of the receiving terminal of calculation sources end 1 ₁With the balanced matrix W of the receiving terminal of source end 2 ₂, method is following:

W ₁＝C ₂F ₂ ^H(G ₁F _rH ₂) ^H(G ₁F _rH ₂F ₂F ₂ ^H(G ₁F _rH ₂) ^H+R _n1) ^-1

W ₂＝C ₁F ₁ ^H(G ₂F _rH ₁) ^H(G ₂F _rH ₁F ₁F ₁ ^H(G ₂F _rH ₁) ^H+R _n2) ^-1

R _n1＝G ₁F _rF _r ^HG ₁ ^H+I _N

R _n2＝G ₂F _rF _r ^HG ₂ ^H+I _N

I _NThe unit matrix of expression N * N, last table () ^HThe expression conjugate transpose;

Iteration two: suppose Fr, W1, W2 is known, the emission pre-coding matrix C of calculation sources end 1 ₁, F ₁, the emission pre-coding matrix C of source end 2 ₂, F ₂, method is following:

The emission pre-coding matrix C of elder generation's calculation sources end 1 ₁, F ₁:

At first to (G ₂F _rH ₁) ^H(G ₂F _rF _r ^HG ₂ ^H+ I _N) ^-1(G ₂F _rH ₁) do characteristic value decomposition, obtain:

(G ₂F _rH ₁) ^H(G ₂F _rF _r ^HG ₂ ^H+ I _N) ^-1(G ₂F _rH ₁)=V Λ V ^H, wherein Λ is a diagonal matrix, V is a unitary matrix;

Then the leading diagonal element among the diagonal matrix Λ is carried out water injection power and distribute, obtain power division matrix Ω, its leading diagonal element does

Wherein (y) ⁺=max (0, y), σ _sBe transmit signal energy, Λ _iBe i the diagonal entry of Λ, u is for making Ω _iSatisfy the power constraint condition

Constant, M wherein ₁Be the antenna number of source end 1, P _S1Transmitting power for source end 1;

Order $D_{}$ ${}_1={({\mathrm{\&Omega;}}^H\mathrm{\&Lambda;\; \&Omega;}+{\mathrm{\&sigma;}}_s^{-2}{I}_{M_1})}^{-1/2}$

To D ₁Do geometric mean and decompose (GMD), obtain:

D ₁=QRF, wherein R is the upper triangular matrix that diagonal entry all equates, Q and F are unitary matrix; Obtain transmitting terminal pre-coding matrix C at last ₁, F ₁, be respectively:

${\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">C</figure-callout>}}_1=\mathrm{diag}\left\{R_{(k,k)}^H\right\}{\left(R^H\right)}^{-1}$

F ₁＝VΩF ^H

Diag{A wherein _{(k, k)}The diagonal matrix formed by all diagonal entries of A of expression;

Adopt similar method, can obtain the emission pre-coding matrix C of source end 2 ₂, F ₂

Iteration three: suppose C ₁, F ₁, C ₂, F ₂, W ₁, W ₂Known, calculate relaying pre-coding matrix F _r, method is following:

Use Lagrangian algorithm, can be with F _rBe expressed as:

$F_r=\mathrm{mat}\left\{{[R_{x2}\&CircleTimes;{\mathrm{<figure-callout\; id="1"\; label="R\; r"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">R</figure-callout>}}_r+R_{x1}\&CircleTimes;R_{r2}+\mathrm{\&lambda;}{R}_x\&CircleTimes;I_n]}^{-1}\mathrm{vec}\left(R_r\right)\right\}$

R wherein _X1=H ₁F ₁F ₁ ^HH ₁ ^H+ I _N

R _x2＝H ₂F ₂F ₂ ^HH ₂ ^H+I _N

R _r1＝G ₁ ^HW ₁ ^HW ₁G ₁

R _r2＝G ₂ ^HW ₂ ^HW ₂G ₂

R _r＝G ₁ ^HW ₁ ^HC ₂F ₂ ^HH ₂ ^H+G ₂ ^HW ₂ ^HC ₁F ₁ ^HH ₁ ^H

R _x＝H ₁F ₁F ₁ ^HH ₁ ^H+H ₂F ₂F ₂ ^HH ₂ ^H+I _N

λ is a Lagrange multiplier, $\mathrm{\&lambda;}\&Element;(0,\sqrt{\mathrm{Trace}\left(R_r{\left(R_x\right)}^{-T}{R}_x{\left(R_x\right)}^{-T}{R_r}^H\right)}/P_r),$ P _rBe repeat transmitted power;

Be the Kronecker computing, vec () is the matrixing vector operation, and mat () is the inverse operation of vec (), and trace () is for getting mark computing, () ^TBe the transposition computing;

The utilization dichotomy is searched in its span λ, equals P up to repeat transmitted power _r, that is:

trace{F _rR _xF _r ^H}＝P _r

Thus, can obtain optimum λ and relaying pre-coding matrix F _r

Preprocess method in said the 5th step is:

x ₁＝F ₁C ₁ ^-1(s ₁+e ₁)

x ₂＝F ₂C ₂ ^-1(s ₂+e ₂)

S wherein ₁=[s ₁1 ..., s _1N1] ^T, s ₂=[s ₂₁..., s _2N2] ^TBe through the signal after the m-QAM modulation, N ₁Be the fluxion that transmits of source end 1, N ₂The fluxion that transmits for source end 2;

e ₁Available following method is asked:

$a_{1k}=s_{1k}-\underset{l=1}{\overset{k-1}{\mathrm{\&Sigma;}}}{B}_1(\mathrm{bk},l)a_{1l}$

e ₁＝a ₁-s ₁

Wherein For under round B ₁=C ₁-I _N1, e ₁=[e ₁₁..., e _1N1] ^T

e ₂Available following method is asked:

$a_{2k}=s_{2k}-\underset{l=1}{\overset{k-1}{\mathrm{\&Sigma;}}}{B}_2(k,l)a_{2l}$

e ₂＝a ₂-s ₂

Wherein

For under round B ₂=C ₂-I _N2, e ₂=[e ₂₁..., e _2N1] ^T

Linear processing methods in said the 6th step is:

Detection processing method in said the 7th step is:

Source end 1:

Source end 2:

Compared with prior art, this beneficial effect of the invention is to have adopted two-way relayed information transmission mode, can improve channel capacity greatly, and end has adopted nonlinear signal processing method in the source, has improved the bit error rate performance of system effectively.

Description of drawings

Fig. 1 is that the bit error rate performance of one embodiment of the invention compares sketch map.

Embodiment

Below in conjunction with accompanying drawing method of the present invention is further described: present embodiment provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment being to implement under the prerequisite with technical scheme of the present invention.

The antenna number M of source end 1 and source end 2 in the present embodiment ₁=4, M ₂=4; The antenna number of relaying is N=4, treats the QPSK modulation symbol of symbol for generating at random of transmission mutually, and the back is to being Ruili (Rayleigh) flat fading with forward channel; The reception noise of relaying and two receiving terminals is the white complex gaussian noise of zero-mean unit variance

The back to the signal to noise ratio of channel does

With The signal to noise ratio of forward channel does

And SNR ₁=SNR ₂=SNR _r=8 20dB, the transmitting power of source end 1 does

The transmitting power of source end 2 does The transmitting power of relaying does

Present embodiment may further comprise the steps:

The first step, source end 1 is to repeat transmitted training sequence S ₁, relaying is according to the signal X that receives ₁Carry out the back to channel estimating, obtain the back of source end 1 and relay well to channel H ₁Source end 2 is to repeat transmitted training sequence S simultaneously ₂, relaying is according to the signal X that receives ₂Carry out the back to channel estimating, obtain the back of source end 2 and relay well to channel H ₂

Described back to channel estimation process is:

${\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">H</figure-callout>}}_1=\sqrt{\frac{{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">M</figure-callout>}}_1}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}1}}}{X}_1{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">S</figure-callout>}}_1^{*}{(\frac{{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">M</figure-callout>}}_1}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}1}}{I}_{M_1}+S_1{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">S</figure-callout>}}_1^{*})}^{-1}$

$H_2=\sqrt{\frac{M_2}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}2}}}{X}_2{S}_2^{*}{(\frac{M_2}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}2}}{I}_{M_2}+S_2{S}_2^{*})}^{-1}$

Wherein: M ₁Be the antenna number of source end 1, M ₂Be the antenna number of source end 2, ρ _{τ 1}Be training sequence S ₁Signal to noise ratio, ρ _{τ 2}Be training sequence S ₂Signal to noise ratio,

T _{τ 1}Be the length of the training sequence of source end 1 emission, T _{τ 2}Be the length of the training sequence of source end 2 emissions,

With

Be the signal that relaying receives, N is the antenna number of relaying,

Be respectively M ₁* M ₁And M ₂* M ₂Unit matrix.

Training sequence length T in the present embodiment _{τ 1}=T _{τ 2}=4, the signal to noise ratio of training sequence is ρ _{τ 1}=ρ _{τ 2}=49,199,999}.

In second step, relaying is simultaneously to source end 1 and source end 2 transmitting training sequence S ₃, source end 1 is according to the signal X that receives ₃Carry out forward channel and estimate, obtain the forward channel G of 1 at relaying and source end ₁, source end 2 is according to the signal X that receives ₄Carry out forward channel and estimate, obtain the back of 2 at relaying and source end to channel G ₂

Described forward channel is estimated to handle, and is:

${\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">G</figure-callout>}}_1=\sqrt{\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}}{(\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}{I}_N+S_3{S}_3^{*})}^{-1}{S}_3{X}_3^{*}$

$G_2=\sqrt{\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}}{(\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}{I}_N+S_3{S}_3^{*})}^{-1}{S}_3{X}_4^{*}$

Wherein: N is the antenna number of relaying, ρ _{τ 3}Be training sequence S ₃Signal to noise ratio,

T _{τ 3}Be the length of the training sequence of repeat transmitted,

With

Be respectively the signal that source end 1 and source end 2 are received, I _NUnit matrix for N * N.

Training sequence length T in the present embodiment _{τ 3}=4, the signal to noise ratio of training sequence is ρ _{τ 3}=49,199,999}.

In the 3rd step, source end 1 and source end 2 are with the forward channel information G that estimates to obtain ₁And G ₂Feed back to relaying.Relaying is according to the emission pre-coding matrix C of all channel information iterative computation source ends 1 ₁, F ₁, the emission pre-coding matrix C of source end 2 ₂, F ₂, relaying pre-coding matrix F _rWith the balanced matrix W of the reception of source end 1 ₁, the balanced matrix W of the reception of source end 2 ₂

Iteration one: suppose C ₁, F ₁, C ₂, F ₂, F _rKnown, the balanced matrix W of the receiving terminal of calculation sources end 1 ₁With the balanced matrix W of the receiving terminal of source end 2 ₂, method is following:

W ₁＝C ₂F ₂ ^H(G ₁F _rH ₂) ^H(G ₁F _rH ₂F ₂F ₂ ^H(G ₁F _rH ₂) ^H+R _n1) ^-1

W ₂＝C ₁F ₁ ^H(G ₂F _rH ₁) ^H(G ₂F _rH ₁F ₁F ₁ ^H(G ₂F _rH ₁) ^H+R _n2) ^-1

R _n1＝G ₁F _rF _r ^HG ₁ ^H+I _N

R _n2＝G ₂F _rF _r ^HG ₂ ^H+I _N

I _NThe unit matrix of expression N * N, last table () ^HThe expression conjugate transpose.

Iteration two: suppose Fr, W1, W2 is known, the emission pre-coding matrix C of calculation sources end 1 ₁, F ₁, the emission pre-coding matrix C of source end 2 ₂, F ₂, method is following:

The emission pre-coding matrix C of elder generation's calculation sources end 1 ₁, F ₁:

At first to (G ₂F _rH ₁) ^H(G ₂F _rF _r ^HG ₂ ^H+ I _N) ^-1(G ₂F _rH ₁) do characteristic value decomposition, obtain:

(G ₂F _rH ₁) ^H(G ₂F _rF _r ^HG ₂ ^H+ I _N) ^-1(G ₂F _rH ₁)=V Λ V ^H, wherein Λ is a diagonal matrix, V is a unitary matrix.

Then the leading diagonal element among the diagonal matrix Λ is carried out water injection power and distribute, obtain power division matrix Ω, its leading diagonal element does

Wherein (y) ⁺=max (0, y), σ _sBe transmit signal energy, Λ _iBe i the diagonal entry of Λ, u is for making Ω _iSatisfy the power constraint condition

Constant, M wherein ₁Be the antenna number of source end 1, P _S1Transmitting power for source end 1.

Order $D_{}$ ${}_1={({\mathrm{\&Omega;}}^H\mathrm{\&Lambda;\; \&Omega;}+{\mathrm{\&sigma;}}_s^{-2}{I}_{M_1})}^{-1/2}$

To D ₁Do geometric mean and decompose (GMD), obtain:

D ₁=QRF, wherein R is the upper triangular matrix that diagonal entry all equates, Q and F are unitary matrix.

Obtain transmitting terminal pre-coding matrix C at last ₁, F ₁, be respectively:

${\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">C</figure-callout>}}_1=\mathrm{diag}\left\{R_{(k,k)}^H\right\}{\left(R^H\right)}^{-1}$

F ₁＝VΩF ^H

Diag{A wherein _{(k, k)}The diagonal matrix formed by all diagonal entries of A of expression.

Adopt similar method, can obtain the emission pre-coding matrix C of source end 2 ₂, F ₂

Iteration three: suppose C ₁, F ₁, C ₂, F ₂, W ₁, W ₂Known, calculate relaying pre-coding matrix F _r, method is following:

Use Lagrangian algorithm, can be with F _rBe expressed as:

$F_r=\mathrm{mat}\left\{{[R_{x2}\&CircleTimes;{\mathrm{<figure-callout\; id="1"\; label="R\; r"\; filenames="HDA0000128990090000011.png"\; state="\{\{state\}\}">R</figure-callout>}}_r+R_{x1}\&CircleTimes;R_{r2}+\mathrm{\&lambda;}{R}_x\&CircleTimes;I_n]}^{-1}\mathrm{vec}\left(R_r\right)\right\}$

R wherein _X1=H ₁F ₁F ₁ ^HH ₁ ^H+ I _N

R _x2＝H ₂F ₂F ₂ ^HH ₂ ^H+I _N

R _r1＝G ₁ ^HW ₁ ^HW ₁G ₁

R _r2＝G ₂ ^HW ₂ ^HW ₂G ₂

R _r＝G ₁ ^HW ₁ ^HC ₂F ₂ ^HH ₂ ^H+G ₂ ^HW ₂ ^HC ₁F ₁ ^HH ₁ ^H

R _x＝H ₁F ₁F ₁ ^HH ₁ ^H+H ₂F ₂F ₂ ^HH ₂ ^H+I _N

λ is a Lagrange multiplier, $\mathrm{\&lambda;}\&Element;(0,\sqrt{\mathrm{Trace}\left(R_r{\left(R_x\right)}^{-T}{R}_x{\left(R_x\right)}^{-T}{R_r}^H\right)}/P_r),$ P _rBe repeat transmitted power.

Be the Kronecker computing, vec () is the matrixing vector operation, and mat () is the inverse operation of vec (), and trace () is for getting mark computing, () ^TBe the transposition computing.

The utilization dichotomy is searched in its span λ, equals P up to repeat transmitted power _r, promptly

trace{F _rR _xF _r ^H}＝P _r

Thus, can obtain optimum λ and relaying pre-coding matrix F _r

In the 4th step, relaying is with the source end that calculates 1 emission pre-coding matrix C ₁, F ₁With the balanced matrix W of reception ₁Feed back to source end 1, with source end 2 emission pre-coding matrix C ₂, F ₂With the balanced matrix W of reception ₂Feed back to source end 2.Simultaneously with channel information H ₁Feed back to source end 1, with H ₂Feed back to source end 2.

The 5th step, 1 pair of preparatory s emission signal s of source end ₁Carry out preliminary treatment, obtain the x that transmits ₁, and with this signal x ₁Be transmitted to relaying, simultaneously 2 pairs of preparatory s emission signal s of source end ₂Carry out preliminary treatment, obtain the x that transmits ₂, and with this signal x ₂Be transmitted to relaying.

Described preliminary treatment is:

x ₁＝F ₁C ₁ ^-1(s ₁+e ₁)

x ₂＝F ₂C ₂ ^-1(s ₂+e ₂)

S wherein ₁=[s ₁₁..., s _1N1] ^T, s ₂=[s ₂₁..., s _2N2] ^TBe that N1 is the fluxion that transmits of source end 1 through the signal after the m-QAM modulation, N2 is the fluxion that transmits of source end 2.

e ₁Available following method is asked:

$a_{1k}=s_{1k}-\underset{l=1}{\overset{k-1}{\mathrm{\&Sigma;}}}{B}_1(\mathrm{bk},l)a_{1l}$

e ₁＝a ₁-s ₁

Wherein

For under round B ₁=C ₁-I _N1, e ₁=[e ₁₁..., e _1N1] ^T

e ₂Available following method is asked:

$a_{2k}=s_{2k}-\underset{l=1}{\overset{k-1}{\mathrm{\&Sigma;}}}{B}_2(k,l)a_{2l}$

e ₂＝a ₂-s ₂

Wherein

For under round B ₂=C ₂-I _N2, e ₂=[e ₂₁..., e _2N1] ^T

In the 6th step, relaying is y to the received signal _rCarry out linear process, obtain signal

And will

Be broadcast to source end 1 and source end 2.

Described linear process is:

In the 7th step, source end 1 is y to the received signal ₁Detect processing, obtain signal Again through with step 5 in identical modular arithmetic obtain signal Simultaneously, source end 2 y to the received signal ₂Detect processing, obtain signal

Again through with step 5 in identical modular arithmetic obtain signal

Said detection is treated to:

Source end 1:

Source end 2:

Fig. 1 is that the bit error rate performance of present embodiment compares sketch map, wherein the antenna number M of source end 1 and source end 2 ₁=4, M ₂=4, the antenna number of relaying is N=4, and the back is to the channel signal to noise ratio snr ₁=SNR ₂, the forward channel signal to noise ratio is SNR _rAnd SNR ₁=SNR ₂=SNR _rH ₁, H ₂, G ₁And G ₂Each element all according to CN (0,1) the independent generation that distribute, generated 10000 secondary channels altogether at random and realized, in each channel realization, all pass 1000 QPSK symbols mutually.Present embodiment with

The following three kinds of processing methods that exist in the prior art do one relatively:

1. only do the receiving terminal equilibrium treatment;

2. only do the Combined Treatment of receiving terminal and relaying;

3. associating transmitting terminal, relaying, receiving terminal is handled, but transmitting terminal adopts the linear process mode.Document (Rui Wang Meixia Tao; " Joint Source and Relay Precoding Designs for MIMO Two-wWay Relay Systems; " IEEE ICC; 2011 (" joint source end in the two-way relay system of MIMO and relaying precoding design ", IEEE international communication conference, 2011)).

As can be seen from Figure 1, under the low signal-to-noise ratio situation, the bit error rate performance of present embodiment and transmitting terminal adopt the linear signal processing mode to be more or less the same.Under the high s/n ratio situation, present embodiment has improved the bit error rate performance of system effectively, and along with signal to noise ratio increases, this performance advantage is also more obvious.

Claims (7)

1. the united signal processing method of source end and relay in the two-way relay system is characterized in that, may further comprise the steps:

The first step, source end 1 is to repeat transmitted training sequence S ₁, relaying is according to the signal X that receives ₁Carry out the back to channel estimating, obtain the back of source end 1 and relay well to channel H ₁, source end 2 is to repeat transmitted training sequence S simultaneously ₂, relaying is according to the signal X that receives ₂Carry out the back to channel estimating, obtain the back of source end 2 and relay well to channel H ₂

In second step, relaying is simultaneously to source end 1 and source end 2 transmitting training sequence S ₃, source end 1 is according to the signal X that receives ₃Carry out forward channel and estimate, obtain the forward channel G of 1 at relaying and source end ₁, source end 2 is according to the signal X that receives ₄Carry out forward channel and estimate, obtain the back of 2 at relaying and source end to channel G ₂

In the 3rd step, source end 1 and source end 2 are with the forward channel information G that estimates to obtain ₁And G ₂Feed back to relaying.Relaying is according to the emission pre-coding matrix C of all channel information iterative computation source ends 1 ₁, F ₁, the emission pre-coding matrix C of source end 2 ₂, F ₂, relaying pre-coding matrix F _rWith the balanced matrix W of the reception of source end 1 ₁, the balanced matrix W of the reception of source end 2 ₂

In the 4th step, relaying is with the source end that calculates 1 emission pre-coding matrix C ₁, F ₁With the balanced matrix W of reception ₁Feed back to source end 1, with source end 2 emission pre-coding matrix C ₂, F ₂With the balanced matrix W of reception ₂Feed back to source end 2; Simultaneously with channel information H ₁Feed back to source end 1, with H ₂Feed back to source end 2;

The 5th step, 1 pair of preparatory s emission signal s of source end ₁Carry out preliminary treatment, obtain the x that transmits ₁, and with this signal x ₁Be transmitted to relaying, simultaneously 2 pairs of preparatory s emission signal s of source end ₂Carry out preliminary treatment, obtain the x that transmits ₂, and with this signal x ₂Be transmitted to relaying;

In the 6th step, relaying is y to the received signal _rCarry out linear process, obtain signal

And will

Send to source end 1 and source end 2;

In the 7th step, source end 1 is y to the received signal ₁Detect processing, obtain signal Again through with step 5 in identical modular arithmetic obtain signal

Simultaneously, source end 2 y to the received signal ₂Detect processing, obtain signal

Again through with step 5 in identical modular arithmetic obtain signal

2. require the united signal processing method of source end and relay in the 1 described two-way relay system according to letter of authorization, it is characterized in that, back in the first step to channel estimation process is:

$H_1=\sqrt{\frac{M_1}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}1}}}{X}_1{S}_1^{*}{(\frac{M_1}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}1}}{I}_{M_1}+S_1{S}_1^{*})}^{-1}$

$H_2=\sqrt{\frac{M_2}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}2}}}{X}_2{S}_2^{*}{(\frac{M_2}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}2}}{I}_{M_2}+S_2{S}_2^{*})}^{-1}$

Wherein: M ₁Be the antenna number of source end 1, M ₂Be the antenna number of source end 2, ρ _{τ 1}Be training sequence S ₁Signal to noise ratio, ρ _{τ 2}Be training sequence S ₂Signal to noise ratio,

T _{τ 1}Be the length of the training sequence of source end 1 emission,

T _{τ 2}Be the length of the training sequence of source end 2 emissions, With Be the signal that relaying receives, N is the antenna number of relaying,

Be respectively M ₁* M ₁And M ₂* M ₂Unit matrix.

3. require the united signal processing method of source end and relay in the 1 described two-way relay system according to letter of authorization, it is characterized in that, the forward channel estimating processing method in said second step is:

$G_1=\sqrt{\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}}{(\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}{I}_N+S_3{S}_3^{*})}^{-1}{S}_3{X}_3^{*}$

$G_2=\sqrt{\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}}{(\frac{N}{{\mathrm{\&rho;}}_{\mathrm{\&tau;}3}}{I}_N+S_3{S}_3^{*})}^{-1}{S}_3{X}_4^{*}$

Wherein: N is the antenna number of relaying, ρ _{τ 3}Be training sequence S ₃Signal to noise ratio,

T _{τ 3}Be the length of the training sequence of repeat transmitted,

With

Be respectively the signal that source end 1 and source end 2 are received, I _NUnit matrix for N * N.

4. require the united signal processing method of source end and relay in the 1 described two-way relay system according to letter of authorization, it is characterized in that, the iterative operation method in said the 3rd step is:

Iteration one: suppose C ₁, F ₁, C ₂, F ₂, F _rKnown, the balanced matrix W of the receiving terminal of calculation sources end 1 ₁With the balanced matrix W of the receiving terminal of source end 2 ₂, method is following:

W ₁＝C ₂F ₂ ^H(G ₁F _rH ₂) ^H(G ₁F _rH ₂F ₂F ₂ ^H(G ₁F _rH ₂) ^H+R _n1) ^-1

W ₂＝C ₁F ₁ ^H(G ₂F _rH ₁) ^H(G ₂F _rH ₁F ₁F ₁ ^H(G ₂F _rH ₁) ^H+R _n2) ^-1

R _n1＝G ₁F _rF _r ^HG ₁ ^H+I _N

R _n2＝G ₂F _rF _r ^HG ₂ ^H+I _N

I _NThe unit matrix of expression N * N, last table () ^HThe expression conjugate transpose;

Iteration two: suppose Fr, W1, W2 is known, the emission pre-coding matrix C of calculation sources end 1 ₁, F ₁, the emission pre-coding matrix C of source end 2 ₂, F ₂, method is following:

The emission pre-coding matrix C of elder generation's calculation sources end 1 ₁, F ₁:

At first to (G ₂F _rH ₁) ^H(G ₂F _rF _r ^HG ₂ ^H+ I _N) ^-1(G ₂F _rH ₁) do characteristic value decomposition, obtain:

(G ₂F _rH ₁) H (G ₂F _rF _r ^HG ₂ ^H+ I _N) ^-1(G ₂F _rH ₁)=V Λ V ^H, wherein Λ is a diagonal matrix, V is a unitary matrix;

Then the leading diagonal element among the diagonal matrix Λ is carried out water injection power and distribute, obtain power division matrix Ω, its leading diagonal element does

Wherein (y) ⁺=max (0, y), σ _sBe transmit signal energy, Λ _iBe i the diagonal entry of Λ, u is for making Ω _iSatisfy the power constraint condition

Constant, M wherein ₁Be the antenna number of source end 1, P _S1Transmitting power for source end 1;

Order $D_1={({\mathrm{\&Omega;}}^H\mathrm{\&Lambda;\; \&Omega;}+{\mathrm{\&sigma;}}_s^{-2}{I}_{M_1})}^{-1/2},$

To D ₁Do geometric mean and decompose (GMD), obtain:

D ₁=QRF, wherein R is the upper triangular matrix that diagonal entry all equates, Q and F are unitary matrix; Obtain transmitting terminal pre-coding matrix C at last ₁, F ₁, be respectively:

$C_1=\mathrm{diag}\left\{R_{(k,k)}^H\right\}{\left(R^H\right)}^{-1}$

F ₁＝VΩF ^H

Diag{A wherein _{(k, k)}The diagonal matrix formed by all diagonal entries of A of expression;

Adopt similar method, can obtain the emission pre-coding matrix C of source end 2 ₂, F ₂

Iteration three: suppose C ₁, F ₁, C ₂, F ₂, W ₁, W ₂Known, calculate relaying pre-coding matrix F _r, method is following: use Lagrangian algorithm, and can be with F _rBe expressed as:

$F_r=\mathrm{mat}\left\{{[R_{x2}\&CircleTimes;R_{r1}+R_{x1}\&CircleTimes;R_{r2}+\mathrm{\&lambda;}{R}_x\&CircleTimes;I_n]}^{-1}\mathrm{vec}\left(R_r\right)\right\}$

R wherein _X1=H ₁F ₁F ₁ ^HH ₁ ^H+ I _N

R _x2＝H ₂F ₂F ₂ ^HH ₂ ^H+I _N

R _r1＝G ₁ ^H?W ₁ ^H?W ₁G ₁

R _r2＝G ₂ ^HW ₂ ^HW ₂G ₂

R _r＝G ₁ ^HW ₁ ^HC ₂F ₂ ^HH ₂ ^H+G ₂ ^HW ₂ ^HC ₁F ₁ ^HH ₁ ^H

R _x＝H ₁F ₁F ₁ ^HH ₁ ^H+H ₂F ₂F ₂ ^HH ₂ ^H+I _N

λ is a Lagrange multiplier, $\mathrm{\&lambda;}\&Element;(0,\sqrt{\mathrm{Trace}\left(R_r{\left(R_x\right)}^{-T}{R}_x{\left(R_x\right)}^{-T}{R_r}^H\right)}/P_r),$ P _rBe repeat transmitted power;

Be the Kronecker computing, vec () is the matrixing vector operation, and mat () is the inverse operation of vec (), and trace () is for getting mark computing, () ^TBe the transposition computing;

The utilization dichotomy is searched in its span λ, equals P up to repeat transmitted power _r, promptly

trace{F _rR _xF _r ^H}＝P _r

Thus, can obtain optimum λ and relaying pre-coding matrix F _r

5. require the united signal processing method of source end and relay in the 1 described two-way relay system according to letter of authorization, it is characterized in that, the preprocess method in said the 5th step is:

x ₁＝F ₁C ₁ ^-1(s ₁+e ₁)

x ₂＝F ₂C ₂ ^-1(s ₂+e ₂)

S wherein ₁=[s ₁₁..., s _1N1] ^T, s ₂=[s ₂₁..., s _2N2] ^TBe that N1 is the fluxion that transmits of source end 1 through the signal after the m-QAM modulation, N2 is the fluxion that transmits of source end 2;

e ₁Available following method is asked:

$a_{1k}=s_{1k}-\underset{l=1}{\overset{k-1}{\mathrm{\&Sigma;}}}{B}_1(\mathrm{bk},l)a_{1l}$

e ₁＝a ₁-s ₁

Wherein For under round B ₁=C ₁-I _N1, e ₁=[e ₁₁..., e _1N1] ^T

e ₂Available following method is asked:

$a_{2k}=s_{2k}-\underset{l=1}{\overset{k-1}{\mathrm{\&Sigma;}}}{B}_2(k,l)a_{2l}$

e ₂＝a ₂-s ₂

Wherein For under round B ₂=C ₂-I _N2, e ₂=[e ₂₁..., e _2N1] ^T

6. require the united signal processing method of source end and relay in the 1 described two-way relay system according to letter of authorization, it is characterized in that, the linear processing methods in said the 6th step is:

7. require the united signal processing method of source end and relay in the 1 described two-way relay system according to letter of authorization, it is characterized in that, the detection processing method in said the 7th step is:

Source end 1:

Source end 2:

Images