CN102035628A - Communication method of multi-input multi-output system assisted by relay - Google Patents

Abstract

The invention discloses a communication method of a multi-input multi-output system assisted by a relay. The multi-input multi-output system assisted by a relay in the communication method comprises a transmitting end with M antennas, a relay transferring station with L antennas and a mobile receiving end with N antennas, wherein K paths of data streams are transmitted by the multi-input multi-output system assisted by the relay every time, and K is the minimum value of M, L and N. The communication method of the multi-input multi-output system assisted by the relay can remarkably improve the receiving end frequency spectrum efficiency by adaptively utilizing the cooperative diversity gain of a through chain under the premise of low complexity and low feedback cost; and compared with the limited feedback precoding technology of the common relay assisted communication system, the adaptive selection cooperative diversity scheme is optimal.

Description

The communication means of the multi-input multi-output system that a kind of relaying is auxiliary

Technical field

The present invention relates to wireless communication system, relate in particular to the distributed limited feedback precoding method of the auxiliary multiple input, multiple output wireless communication system of a kind of relaying.

Background technology

The relay wireless communications system have Extended Cell coverage rate, overcome " dead band " effect, improve the cell boarder receiving terminal channel quality, overcome advantages such as shadow effect.The thought of trunking traffic before three more than ten years just the someone propose, this thought is the simplest bikini communication, comprising a transmitting terminal, a relay station and a receiving terminal, and these three nodes all have only an antenna.In recent years, the researcher is respectively from the angle research trunking traffic of trunk protocol, information theory and specific algorithm, for example: at the wireless relay communication system of the single output of single input, three kinds of traditional trunk protocols are arranged, comprise that amplifying forwarding, decoding forwarding and compression transmits, wherein amplify the forward relay agreement owing to not needing to decode direct forward signal, it is all very low to handle complexity and power consumption, so be most widely used.Simultaneously, multiple-input-multiple-output communication system can improve the validity and the reliability of communicating by letter by utilizing spatial reuse gain, space diversity gain and array gain.MIMO technique and the relaying technique advantage that can utilize the two that combines is improved communication performance further.

Although under most of scenes, use the renewable relaying of decoding pass-through mode to have more advantage than the non-renewable relaying that amplifies pass-through mode, it can produce higher computation complexity and time delay, and has potential safety hazard.For the auxiliary multiple-input-multiple-output communication system of the relaying that amplifies forward mode, document (O.Munoz-Medina, J.Vidal and A.Agustin, " Linear transceiver design in non-regenerative relays with channel state information; " IEEETrans.Signal Process., vol.55, no.6, pp.2593-2604, June 2007) to have studied under the situation of the complete known double bounce channel information of relay station, relay station is to the optimum linearity transceiver design of receiving terminal; The transmission that studies show that the double bounce communication system can be converted to the parallel data flow transmission on a plurality of orthogonal sub-channels.Document (I.Hammerstrom and A.Wittneben, " Power allocation schemes for ampliy-and-forward MIMO-OFDM relay links " IEEE Trans.Wireless Commun., vol.6, no.8, pp.2798-2802, Aug.2007) provided the co-design scheme of the linear transceiver of double bounce communication system quasi-optimal, simulation result shows that it has obtained good performance gain, but need the computing of high complexity simultaneously.

It should be noted that above-mentioned algorithm all needs the channel condition information of complete known double bounce, this is also inapplicable in the frequency-division duplex communication system of reality.In order to overcome this problem, document (B.Khoshnevis, W.Yu and R.Adve, " Grassmannian beamforming for MIMO amplify-and-forward relaying " IEEE J.Sel.Areas.Commun.vol.26, no.8, pp.1397-1407 Oct.2008.) has proposed a kind of Limited Feedback beam shaping algorithm that amplifies forward relay that is applicable to, it has adopted the Grassmannian code book to reduce feedback overhead.But it only is applicable to the situation of beam shaping, and is inconvenient to expand to the pre-coding system of a plurality of son streams.All dispose at each node under the situation of many antennas, this algorithm can not obtain the spatial multiplexing gain of multi-input multi-ouput channel fully.Document (Yongming Huang, Luxi Yang, Mats Bengtsson, and Bjorn Ottersten, " A limited feedback joint precoding for amplify-and-forward relaying " IEEE Trans.Signal Processing, March 2010,58 (3): 1347-1357.) further proposed a kind of limited feedback precoding algorithm that amplifies forward relay that is applicable to, the expense that its need are very little just can fully obtain the space division multiplexing gain of multi-input multi-ouput channel; But it only is applicable to the situation of ignoring tie link.When tie link was better, this algorithm can not obtain the transmission diversity gain of tie link.

Summary of the invention

Goal of the invention: in order to overcome the deficiencies in the prior art, the invention provides the distributed limited feedback precoding method of transmitting terminal and relay station in the down link of the auxiliary multiple-input-multiple-output communication system of a kind of relaying, under the prerequisite of low complex degree and low feedback overhead, obtain higher spectrum efficiency.

Technical scheme: for achieving the above object, the technical solution used in the present invention is:

The communication means of the multi-input multi-output system that a kind of relaying is auxiliary, the auxiliary multi-input multi-output system of relaying in the described communication means comprises that one has the transmitting terminal of M root antenna, a relaying repeater station with L root antenna and the mobile receiving terminal with N root antenna, the auxiliary multi-input multi-output system of described relaying transmits K circuit-switched data stream at every turn, and wherein K is the minimum value among M, L, the N; Described communication means comprises the steps:

(1) mobile receiving terminal obtains whole channel informations, and formulates coordination strategy in view of the above, and the relevant information of this coordination strategy is fed back to the relaying repeater station; The relevant information of described this shift strategy can be for assisting strategy sign, needs the cooperation transmission of transmitting terminal such as " 1 " expression, and " 0 " expression does not need the cooperation transmission of transmitting terminal;

(2) relaying repeater station and mobile receiving terminal are selected separately optimum pre-coding matrix according to coordination strategy and current channel condition distributed earth, the relaying repeater station feeds back to transmitting terminal with the relevant information of its optimum pre-coding matrix, and mobile receiving terminal feeds back to the relaying repeater station with the relevant information of its optimum pre-coding matrix;

(3) transmitting terminal one road signal that will need to transmit is converted into parallel signal more than a road, and the signal after will transforming modulates accordingly and encode, multiply by the optimum pre-coding matrix of relaying repeater station feedback again after, send to the relaying repeater station;

(4) relaying repeater station received signal, and, send to mobile receiving terminal with behind the optimum pre-coding matrix of signal times that receives with mobile receiving terminal feedback;

(5) mobile receiving terminal received signal, and handle.

In the described step (1), mobile receiving terminal is formulated coordination strategy according to the channel information of tie link and two-hop link, and the relevant information of this coordination strategy is fed back to the relaying repeater station; (1bit) feeds back to the relaying repeater station such as the information that will represent this coordination strategy.

In the described communication means, at first need according to ignoring and the ratio of suboptimum achievable rate when considering tie link, judge whether mobile receiving terminal needs to utilize the transmission diversity of tie link, if judged result is for being, be that the tie link channel condition is when better, then in the step (1), mobile receiving terminal is given the relaying repeater station with the relevant information of coordination strategy and the feedback of channel information of tie link; In the step (5), the signal that mobile receiving terminal receives comprises the signal of relaying repeater station transmission and the signal of the tie link that last time slot transmitting terminal sends, these two signals merge accordingly again, so that the signal to noise ratio of mobile receiving terminal is improved, make it make full use of the diversity gain of tie link.If judged result is not, then in the step (1), mobile receiving terminal only needs the relevant information of coordination strategy is fed back to the relaying repeater station; In the step (5), mobile receiving terminal only need receive the signal that the relaying repeater station sends.

Described mobile receiving terminal can obtain whole road information, and the adaptive selection collaboration diversity strategy of energy, and identifier is fed back to the relaying repeater station.

Described transmitting terminal needs to preserve identical code book respectively with relaying repeater station, relaying repeater station and mobile receiving terminal, comprises a pre-coding matrix in the described code book at least; In the described step (2), relaying repeater station and mobile receiving terminal are selected separately optimum pre-coding matrix according to coordination strategy, current channel condition and code word selection algorithm distributed earth, and will represent the feedback information of optimum pre-coding matrix separately to give transmitting terminal and relaying repeater station, the information of described representative optimum pre-coding matrix separately is the index of optimum pre-coding matrix in described code book separately.

Described code word selection algorithm is the code word selection algorithm of considering the tie link diversity gain or the code word selection algorithm of ignoring tie link.

In the described step (3), the road signal that transmitting terminal will need to transmit is converted into parallel K road signal element.

In the described step (4), the relaying repeater station receives the signal that transmitting terminal sends, and after the signal times that receives amplified with the optimum pre-coding matrix of mobile receiving terminal feedback, sends to mobile receiving terminal.

In the described step (5), mobile receiving terminal adopts least mean-square error receiver received signal, and decodes to the received signal and handle.

In the described step (2), relaying repeater station and mobile receiving terminal are determined the code word selection algorithm according to coordination strategy; Select separately optimum pre-coding matrix by the code word selection mode determined by the code word selection algorithm and current channel condition again.

Mobile receiving terminal calculates respectively to be ignored and considers under two kinds of different situations of tie link the suboptimum achievable rate of double bounce communication system; Obtain both ratio Wherein:

$C_{\mathrm{wod}}=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\log }_2(1+\frac{\mathrm{\&gamma;}{\mathrm{\&lambda;}}_{1,\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">k</figure-callout>}}^2{\mathrm{\&lambda;}}_{2,k}^2{b}_k^2}{({\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">N</figure-callout>}}_2+{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1{\mathrm{\&lambda;}}_{2,k}^2{b}_k^2)})$

${\mathrm{<figure-callout\; id="2"\; label="b\; k"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">b</figure-callout>}}_k^{}=\frac{P_{2}K}{K^2{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1+{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_{1,\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">k</figure-callout>}}^2}$

$C_{\mathrm{wd}}=\frac{1}{2}{\mathrm{<figure-callout\; id="2"\; label="log"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">log</figure-callout>}}_2|I+\mathrm{\&gamma;}{\mathrm{HH}}^H{R}_n^{-1}|$

$H=\left(\begin{array}{c}{H}_0{W}_1\\ H_2{W}_2{H}_1{W}_1\end{array}\right),R_n=\left(\begin{array}{cc}{R}_{{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="HDA0000039431260000022.png"\; state="\{\{state\}\}">n</figure-callout>}}_0}& 0\\ 0& H_2{W}_2{R}_{n_1}{W}_2^H{H}_2^H{R}_{{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">n</figure-callout>}}_2}\end{array}\right)$

${\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">W</figure-callout>}}_1={\stackrel{\&OverBar;}{V}}_1,{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">W</figure-callout>}}_2=\sqrt{\mathrm{\&rho;}}{\stackrel{\&OverBar;}{V}}_2{\stackrel{\&OverBar;}{U}}_1^H$

$\mathrm{tr}\{\frac{P_1}{K}{W}_2{H}_1{W}_1{W}_1^H{H}_1^H{W}_2^H+N_1{W}_2{W}_2^H\}={\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2$

Wherein, H ₀Be the channel matrix of tie link, H ₁And H ₂Represent first jumping and second channel matrix of jumping in the two-hop link respectively; λ _{I, k}, k=1 ..., K is a channel matrix H _i, i=0,1,2 preceding K characteristic value;

With

Be V ₁, V ₂And U ₁The submatrix that constitutes of preceding K row;

Be respectively the covariance matrix of the first time slot relaying repeater station and mobile receiving terminal end noise vector,

Be the covariance matrix that second time slot moves receiving terminal end noise vector, noise vector n _k: CN (0, N _kI _N), k=0,1,2;

P ₁And P ₂Be respectively the power constraint of transmitting terminal and relaying repeater station, multiply by coefficient ρ is in order to satisfy the Power Limitation of relaying repeater station.

When mobile receiving terminal need utilize the diversity gain of tie link, when promptly the tie link channel condition was better, the code word selection mode of relaying repeater station and receiving terminal was as follows:

The relaying repeater station:

${\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">F</figure-callout>}}_1^{*}=\underset{F_{}}{\arg \mathrm{<figure-callout\; id="1"\; label="max\; F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">max</figure-callout>}}\frac{1}{4}\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\log }_2(1+\frac{\mathrm{\&gamma;}}{{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1}{\mathrm{\&lambda;}}_k\left(H_1{F}_1{F}_1^H{H}_1^H\right))+\frac{1}{4}{\mathrm{<figure-callout\; id="2"\; label="log"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">log</figure-callout>}}_2\left|\mathrm{\&gamma;}{\mathrm{\&lambda;}}_K\left(F_1{F}_1^H\right)H_0^H{R}_{n_0}^{-1}{\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="HDA0000039431260000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_0\right|$

Receiving terminal:

${\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">F</figure-callout>}}_2^{*}=\underset{F_{}}{\arg \mathrm{<figure-callout\; id="2"\; label="max\; F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">max</figure-callout>}}{\log }_2\left(\frac{{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2{\mathrm{<figure-callout\; id="1"\; label="KN"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">KN</figure-callout>}}_1{\mathrm{\&lambda;}}_K^2\left(H_2{F}_2\right)}{(K^2{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1+{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_{1,k}^2){\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">N</figure-callout>}}_2+{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2{\mathrm{<figure-callout\; id="1"\; label="KN"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">KN</figure-callout>}}_1{\mathrm{\&lambda;}}_1^2\left(H_2{F}_2\right)}\right)$

At this moment, system with speed is:

$C=\underset{i=1}{\overset{K}{\mathrm{\&Sigma;}}}{\log }_2(1+{\mathrm{SNR}}_i)$

Wherein, the Signal to Interference plus Noise Ratio of each signal subspace stream can be expressed as form:

${\mathrm{SNR}}_i=\frac{{\left|{\left(G^H{R}_n^{-\frac{1}{2}}H\right)}_{\mathrm{ii}}\right|}^2}{\underset{j\&NotEqual;i}{\mathrm{\&Sigma;}}{\left|{\left(G^H{R}_n^{-\frac{1}{2}}H\right)}_{\mathrm{ij}}\right|}^2+{\left|\right|{\left(G^H\right)}_i\left|\right|}^2},i=1,...,K$

Receiving terminal adopts the least mean-square error receiver to receive, and receives processing array and is:

$G={(R_n^{-\frac{1}{2}}H{\left(R_n^{-\frac{1}{2}}H\right)}^H+I)}^{-1}{R}_n^{-\frac{1}{2}}H$

$H=\left(\begin{array}{c}{H}_0{W}_1\\ H_2{W}_2{H}_1{W}_1\end{array}\right),R_n=\left(\begin{array}{cc}{R}_{{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="HDA0000039431260000022.png"\; state="\{\{state\}\}">n</figure-callout>}}_0}& 0\\ 0& H_2{W}_2{R}_{n_1}{W}_2^H{H}_2^H{R}_{{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">n</figure-callout>}}_2}\end{array}\right)$

${\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">W</figure-callout>}}_1={\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">F</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">W</figure-callout>}}_2=\sqrt{\mathrm{\&rho;}}{F}_2{\stackrel{\&OverBar;}{U}}_1^H$

Multiply by coefficient ρ is in order to satisfy the power constraint of relay station.

Beneficial effect: the communication means of the auxiliary multi-input multi-output system of a kind of relaying provided by the invention, adopt precoding codebook to quantize, provided the precoding technique that a kind of distributed code word is selected, can make full use of the diversity gain of the collaborative transmission of mobile transmitting terminal, this algorithm significantly reduces feedback overhead and delay of feedback under the prerequisite of sacrificing very little performance, and has very low computation complexity; Simultaneously, at tie link when relatively poor, the situation that it can not fine acquisition diversity gain has further proposed adaptive selection collaboration diversity scheme; Compare associating precoding design and often need whole channel informations simultaneously, can cause very high channel feedback expense and feedback delay in Frequency Division Duplexing (FDD) (FDD) system, the present invention can obtain higher spectrum efficiency under the prerequisite of low complex degree and low feedback overhead.

Description of drawings

Fig. 1 is the structural representation of the auxiliary multi-input multi-output system of the relaying in the inventive method;

Fig. 2 is the algorithm flow chart of the inventive method;

Fig. 3 (a) is the spectrum efficiency of the inventive method under different signal to noise ratios with Fig. 3 (b);

Fig. 4 (a) is the cumulative probability distribution of the inventive method spectrum efficiency under different signal to noise ratios with Fig. 4 (b).

Embodiment

Below in conjunction with accompanying drawing the present invention is done further explanation.

The communication means of the multi-input multi-output system that a kind of relaying is auxiliary, the multi-input multi-output system that relaying in the described communication means is assisted as shown in Figure 1, comprise a transmitting terminal with M root antenna, relaying repeater station and a mobile receiving terminal with N root antenna with L root antenna, the auxiliary multi-input multi-output system of described relaying transmits K circuit-switched data stream at every turn, wherein K is M, L, minimum value among the N, described transmitting terminal and relaying repeater station, the relaying repeater station needs to preserve identical code book respectively with mobile receiving terminal, comprises a pre-coding matrix in the described code book at least; Described communication means judges at first whether mobile receiving terminal needs to utilize the transmission diversity of tie link, carries out following steps then:

(1) mobile receiving terminal is formulated coordination strategy according to the channel information of tie link and two-hop link, and the relevant information of this coordination strategy is fed back to the relaying repeater station; If mobile receiving terminal need utilize the transmission diversity of tie link, then mobile receiving terminal also needs to give the relaying repeater station with the feedback of channel information of tie link;

(2) relaying repeater station and mobile receiving terminal are determined the code word selection algorithm according to coordination strategy; Select separately optimum pre-coding matrix by the code word selection mode determined by the code word selection algorithm and current channel condition again, on behalf of the feedback information of its optimum pre-coding matrix, the relaying repeater station will give transmitting terminal, and on behalf of the feedback information of its optimum pre-coding matrix, mobile receiving terminal will give the relaying repeater station; Wherein, represent the information of optimum pre-coding matrix to be the index of this optimum pre-coding matrix in code book, the code word selection algorithm comprises the code word selection algorithm of considering the tie link diversity gain and the code word selection algorithm of ignoring tie link;

(3) transmitting terminal will need the transmission of one line signal to be converted into parallel K road signal, and the signal after will transforming modulates accordingly and encode, multiply by the optimum pre-coding matrix of relaying repeater station feedback again after, send to the relaying repeater station;

(4) relaying repeater station received signal, and, send to mobile receiving terminal with after amplifying behind the optimum pre-coding matrix of signal times that receives with mobile receiving terminal feedback;

(5) mobile receiving terminal adopts least mean-square error receiver received signal, and decodes and handle; If mobile receiving terminal need utilize the transmission diversity of tie link, the signal that then mobile receiving terminal receives comprises the signal of relaying repeater station transmission and the signal of the tie link that last time slot transmitting terminal sends, and these two signal demands merge processing accordingly, so that the signal to noise ratio of mobile receiving terminal is improved.

Be illustrated in figure 2 as the algorithm flow chart of the inventive method.Determine at first among Fig. 2 whether mobile receiving terminal needs to utilize the cooperation transmission diversity of transmitting terminal, and give the relaying repeater station the feedback of channel information of coordination strategy and tie link; Then, the coordination strategy that relaying repeater station and mobile receiving terminal are determined according to previous moment adopts suitable code word selection algorithm distributed earth selection optimum pre-coding matrix separately, and codewords indexes is fed back to transmitting terminal and relaying repeater station respectively.A complete communication process is finished in two time slots: first time slot transmitting terminal is converted into parallel K road signal subspace stream with a circuit-switched data signal, and the codewords indexes of utilizing previous moment relaying repeater station feedback selects corresponding pre-coding matrix to send signal, the relaying repeater station receives the transmission signal of transmitting terminal, and whether the coordination strategy decision that mobile receiving terminal is then determined according to previous moment receives the signal of tie link; Second time slot, corresponding pre-coding matrix is selected according to the codewords indexes of mobile receiving terminal feedback by the relaying repeater station, handles and transmit the signal that receives, and mobile receiving terminal receives the signal of relaying repeater station and handles accordingly.Specific algorithm is as follows:

Step a: determine coordination strategy

(a1) mobile receiving terminal calculates respectively and ignores and consider under two kinds of different situations of tie link the suboptimum achievable rate of double bounce communication system; Obtain both ratio

Wherein:

$C_{\mathrm{wod}}=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\log }_2(1+\frac{\mathrm{\&gamma;}{\mathrm{\&lambda;}}_{1,\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">k</figure-callout>}}^2{\mathrm{\&lambda;}}_{2,k}^2{b}_k^2}{({\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">N</figure-callout>}}_2+{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1{\mathrm{\&lambda;}}_{2,k}^2{b}_k^2)})$

$b_{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">k</figure-callout>}}^2=\frac{P_{2}K}{K^2{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1+{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_{1,\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">k</figure-callout>}}^2}$

$C_{\mathrm{wd}}=\frac{1}{2}{\mathrm{<figure-callout\; id="2"\; label="log"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">log</figure-callout>}}_2|I+\mathrm{\&gamma;}{\mathrm{HH}}^H{R}_n^{-1}|$

$H=\left(\begin{array}{c}{H}_0{W}_1\\ H_2{W}_2{H}_1{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\end{array}\right),R_n=\left(\begin{array}{cc}{\mathrm{<figure-callout\; id="0"\; label="R\; n"\; filenames="HDA0000039431260000022.png"\; state="\{\{state\}\}">R</figure-callout>}}_{n_{}}& 0\\ 0& H_2{W}_2{R}_{n_1}{W}_2^H{H}_2^{\mathrm{<figure-callout\; id="2"\; label="H\; R\; n"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">H</figure-callout>}}{R}_{n_{}}{{}_2}_{}\end{array}\right)$

${\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">W</figure-callout>}}_1={\stackrel{\&OverBar;}{V}}_1,{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">W</figure-callout>}}_2=\sqrt{\mathrm{\&rho;}}{\stackrel{\&OverBar;}{V}}_2{\stackrel{\&OverBar;}{U}}_1^H$

$\mathrm{tr}\{\frac{P_1}{K}{W}_2{H}_1{W}_1{W}_1^H{H}_1^H{W}_2^H+N_1{W}_2{W}_2^H\}={\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2$

Wherein, H ₀Be the channel matrix of tie link, H ₁And H ₂Represent first jumping and second channel matrix of jumping in the two-hop link respectively; λ _{I, k}, k=1 ..., K is a channel matrix H _i, i=0,1,2 preceding K characteristic value;

With

Be V ₁, V ₂And U ₁The submatrix that constitutes of preceding K row;

Be respectively the covariance matrix of the first time slot relaying repeater station and mobile receiving terminal end noise vector,

Be the covariance matrix that second time slot moves receiving terminal end noise vector, noise vector n _k: CN (0, N _kI _N), k=0,1,2;

P ₁And P ₂Be respectively the power constraint of transmitting terminal and relaying repeater station, multiply by coefficient ρ is in order to satisfy the Power Limitation of relaying repeater station.

(a2) mobile receiving terminal feeds back to the relaying repeater station with coordination strategy identifier flag, if mobile receiving terminal need utilize the diversity gain (this moment flag=1, otherwise flag=0) of tie link, then mobile receiving terminal also need feed back the channel information H of tie link simultaneously ₀To the relaying repeater station.

Step b: the pre-coding matrix of determining transmitting terminal and relaying repeater station

(b1) when flag=1, the code word selection mode of relaying repeater station and mobile receiving terminal is as follows:

The relaying repeater station:

${\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">F</figure-callout>}}_1^{*}=\underset{F_{}}{\mathrm{<figure-callout\; id="1"\; label="arg\; max\; F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">arg</figure-callout>}\max }\frac{1}{4}\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\log }_2(1+\frac{\mathrm{\&gamma;}}{{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1}{\mathrm{\&lambda;}}_k\left(H_1{F}_1{F}_1^H{H}_1^H\right))+\frac{1}{4}{\mathrm{<figure-callout\; id="2"\; label="log"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">log</figure-callout>}}_2\left|\mathrm{\&gamma;}{\mathrm{\&lambda;}}_K\left(F_1{F}_1^H\right)H_0^H{R}_{n_0}^{-1}{\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="HDA0000039431260000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_0\right|$

Mobile receiving terminal:

${\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">F</figure-callout>}}_2^{*}=\underset{F_{}}{\mathrm{<figure-callout\; id="2"\; label="arg\; max\; F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">arg</figure-callout>}\max }{\log }_2\left(\frac{{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2{\mathrm{<figure-callout\; id="1"\; label="KN"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">KN</figure-callout>}}_1{\mathrm{\&lambda;}}_K^2\left(H_2{F}_2\right)}{(K^2{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1+{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_{1,k}^2){\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">N</figure-callout>}}_2+{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2{\mathrm{<figure-callout\; id="1"\; label="KN"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">KN</figure-callout>}}_1{\mathrm{\&lambda;}}_1^2\left(H_2{F}_2\right)}\right)$

(b2) when flag=0, receiving terminal will be ignored the diversity gain of tie link, and the code word selection mode of this moment is respectively:

The relaying repeater station: ${\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">F</figure-callout>}}_1^{*}=\underset{F_{}}{\mathrm{<figure-callout\; id="1"\; label="arg\; max\; F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">arg</figure-callout>}\max }{\mathrm{\&lambda;}}_K\left\{F_1^H{\stackrel{\&OverBar;}{V}}_1{\stackrel{\&OverBar;}{D}}_1^2{\stackrel{\&OverBar;}{V}}_1^H{F}_1\right\}$

Mobile receiving terminal: ${\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">F</figure-callout>}}_2^{*}=\underset{F_{}}{\mathrm{<figure-callout\; id="2"\; label="arg\; max\; F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">arg</figure-callout>}\max }{\mathrm{\&lambda;}}_K\left\{F_2^H{H}_2^H{H}_2{F}_2\right\}$

Wherein code book adopts the code book of 3GPP LTE.

Step c: step a, b have finished the selection of double bounce cooperative transmission strategy and pre-coding matrix, in order to obtain the performance evaluating of system, need to calculate the relaying subsidiary communications system and speed

(c1) when flag=1, system with speed is:

$C=\underset{i=1}{\overset{K}{\mathrm{\&Sigma;}}}{\log }_2(1+{\mathrm{SNR}}_i)$

The Signal to Interference plus Noise Ratio of each son stream can be expressed as form:

${\mathrm{SNR}}_i=\frac{{\left|{\left(G^H{R}_n^{-\frac{1}{2}}H\right)}_{\mathrm{ii}}\right|}^2}{\underset{j\&NotEqual;i}{\mathrm{\&Sigma;}}{\left|{\left(G^H{R}_n^{-\frac{1}{2}}H\right)}_{\mathrm{ij}}\right|}^2+{\left|\right|{\left(G^H\right)}_i\left|\right|}^2},i=1,...,K$

Mobile receiving terminal adopts the least mean-square error receiver, receives processing array to be:

$G={(R_n^{-\frac{1}{2}}H{\left(R_n^{-\frac{1}{2}}H\right)}^H+I)}^{-1}{R}_n^{-\frac{1}{2}}H$

$H=\left(\begin{array}{c}{H}_0{W}_1\\ H_2{W}_2{H}_1{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\end{array}\right),R_n=\left(\begin{array}{cc}{\mathrm{<figure-callout\; id="0"\; label="R\; n"\; filenames="HDA0000039431260000022.png"\; state="\{\{state\}\}">R</figure-callout>}}_{n_{}}& 0\\ 0& H_2{W}_2{R}_{n_1}{W}_2^H{H}_2^{\mathrm{<figure-callout\; id="2"\; label="H\; R\; n"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">H</figure-callout>}}{R}_{n_{}}{{}_2}_{}\end{array}\right)$

${\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">W</figure-callout>}}_1={\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">F</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">W</figure-callout>}}_2=\sqrt{\mathrm{\&rho;}}{F}_2{\stackrel{\&OverBar;}{U}}_1^H$

(c2) when flag=0, system with speed is:

$C={\mathrm{<figure-callout\; id="2"\; label="log"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">log</figure-callout>}}_2\frac{1}{\underset{k=1}{\overset{K}{\mathrm{\&Pi;}}}{\left[M\right]}_{\mathrm{kk}}}$

Wherein [M] _KkK the diagonal entry of expression M, mobile receiving terminal adopts the least mean-square error receiver, then

$M={(I_K+\frac{P_1}{K}{W}_1^H{H}_1^H{(I_L-(I_L+\frac{N_1}{N_2}{\left(H_2{W}_2\right)}^H\left(H_2{W}_2\right)))}^{-1}{H}_1{W}_1)}^{-1}$

${\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">W</figure-callout>}}_1={\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="HDA0000039431260000012.png,HDA0000039431260000021.png"\; state="\{\{state\}\}">F</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="HDA0000039431260000012.png,HDA0000039431260000022.png"\; state="\{\{state\}\}">W</figure-callout>}}_2=\sqrt{\mathrm{\&rho;}}{F}_2{\stackrel{\&OverBar;}{U}}^H$

Multiply by coefficient ρ is in order to satisfy the power constraint of relay station.

Fig. 3 (a), Fig. 3 (b) and Fig. 4 (a), Fig. 4 (b) has provided in the auxiliary multiple-input-multiple-output communication system of relaying under the different code word selection schemes, the simulation curve that system spectral efficiency and cumulative probability distribute, SNR0 is the signal to noise ratio of tie link, SNR1 and SNR2 represent respectively in the two-hop link that first jumps and the signal to noise ratio of second jumping: Fig. 3 (a) and Fig. 3 (b) are illustrated in the relaying subsidiary communications system under the different pre-encoding codeword selection algorithms, mobile receiving terminal spectrum efficiency is along with signal to noise ratio changes and the simulation curve of variation, Fig. 4 (a) and Fig. 4 (b) are illustrated in the relaying subsidiary communications system under the different pre-encoding codeword selection algorithms, the simulation curve that mobile receiving terminal spectrum efficiency accumulated probability distributes.In the simulation example, the antenna configurations of transmitting terminal, relaying repeater station and mobile receiving terminal is respectively (4,4,2).By emulation as seen, combination property of the present invention in an embodiment obviously is better than existing distributed code word selection scheme: the present invention program can be under the prerequisite of low complex degree and low feedback overhead, adaptively utilizes the collaboration diversity gain of tie link significantly to promote the receiving terminal spectrum efficiency; Compare with common relaying subsidiary communications system limited feedback precoding technology, this adaptive selection collaboration diversity scheme is optimum.

The above only is a preferred implementation of the present invention; be noted that for those skilled in the art; under the prerequisite that does not break away from the principle of the invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (9)

1. the communication means of the auxiliary multi-input multi-output system of a relaying, it is characterized in that: the auxiliary multi-input multi-output system of the relaying in the described communication means comprises that one has the transmitting terminal of M root antenna, an amplification relaying repeater station with L root antenna and the mobile receiving terminal with N root antenna, the auxiliary multi-input multi-output system of described relaying transmits K circuit-switched data stream at every turn, and wherein K is the minimum value among M, L, the N; Described communication means comprises the steps:

(1) mobile receiving terminal is formulated coordination strategy, and the relevant information of this coordination strategy is fed back to the relaying repeater station;

(2) relaying repeater station and mobile receiving terminal are selected separately optimum pre-coding matrix according to coordination strategy and current channel condition distributed earth, the relaying repeater station feeds back to transmitting terminal with the relevant information of its optimum pre-coding matrix, and mobile receiving terminal feeds back to the relaying repeater station with the relevant information of its optimum pre-coding matrix;

(3) transmitting terminal one road signal that will need to transmit is converted into parallel signal more than a road, and the signal after will transforming modulates accordingly and encode, multiply by the optimum pre-coding matrix of relaying repeater station feedback again after, send to the relaying repeater station;

(4) relaying repeater station received signal, and, send to mobile receiving terminal with behind the optimum pre-coding matrix of signal times that receives with mobile receiving terminal feedback;

(5) mobile receiving terminal received signal, and handle.

2. the communication means of the multi-input multi-output system that relaying according to claim 1 is auxiliary, it is characterized in that: in the described step (1), mobile receiving terminal is formulated coordination strategy according to the channel information of tie link and two-hop link, and the relevant information of this coordination strategy is fed back to the relaying repeater station.

3. the communication means of the multi-input multi-output system that relaying according to claim 1 is auxiliary, it is characterized in that: in the described communication means, judge at first whether mobile receiving terminal utilizes the transmission diversity of tie link, if judged result is for being, then in the step (1), mobile receiving terminal is given the relaying repeater station with the relevant information of coordination strategy and the feedback of channel information of tie link; In the step (5), the signal that mobile receiving terminal receives comprises the signal of relaying repeater station transmission and the signal of the tie link that transmitting terminal sends; If judged result is not, then in the step (1), mobile receiving terminal only needs the relevant information of coordination strategy is fed back to the relaying repeater station; In the step (5), mobile receiving terminal only need receive the signal that the relaying repeater station sends.

4. the communication means of the multi-input multi-output system that relaying according to claim 1 is auxiliary, it is characterized in that: described transmitting terminal needs to preserve identical code book respectively with relaying repeater station, relaying repeater station and mobile receiving terminal, comprises a pre-coding matrix in the described code book at least; In the described step (2), relaying repeater station and mobile receiving terminal are selected separately optimum pre-coding matrix according to coordination strategy, current channel condition and code word selection algorithm distributed earth, and will represent the feedback information of optimum pre-coding matrix separately to give transmitting terminal and relaying repeater station, the information of described representative optimum pre-coding matrix separately is the index of optimum pre-coding matrix in described code book separately.

5. the communication means of the multi-input multi-output system that relaying according to claim 4 is auxiliary is characterized in that: described code word selection algorithm is the code word selection algorithm of considering the tie link diversity gain or the code word selection algorithm of ignoring tie link.

6. the communication means of the multi-input multi-output system that relaying according to claim 5 is auxiliary, it is characterized in that: in the described step (2), relaying repeater station and mobile receiving terminal are determined the code word selection algorithm according to coordination strategy; Select separately optimum pre-coding matrix by the code word selection mode determined by the code word selection algorithm and current channel condition again.

7. the communication means of the multi-input multi-output system that relaying according to claim 1 is auxiliary, it is characterized in that: in the described step (3), the road signal that transmitting terminal will need to transmit is converted into parallel K road signal element.

8. the communication means of the multi-input multi-output system that relaying according to claim 1 is auxiliary, it is characterized in that: in the described step (4), the relaying repeater station receives the signal that transmitting terminal sends, and after the signal times that receives amplified with the optimum pre-coding matrix of mobile receiving terminal feedback, send to mobile receiving terminal.

9. the communication means of the multi-input multi-output system that relaying according to claim 1 is auxiliary is characterized in that: in the described step (5), mobile receiving terminal adopts least mean-square error receiver received signal, and decodes to the received signal and handle.

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