CN102710313B - Increment relay transmission method based on multi-relay single-source and single-sink cooperative network - Google Patents

Abstract

The invention discloses an increment relay transmission method based on multi-relay single-source and single-sink cooperative network. The method comprises the following steps: 1. a source S broadcasts a signal sequence, and all relays R receive the signal sequence; 2. each relay is numbered, and the relays carrying out magnifying and transmitting treatment to the signal sequence successively; 3. after a sink D receives the signal sequence transmitted from the ith relay, maximum ratio combining is performed on the received i signals, interrupt event judgment is carried out, and then a judgment result is shown by using single bit information; 4. the single bit information B is fed back to the source S and all relays by D, if interrupt happens, the i+1th relay transmits the signal in the next time slot, S keeps silent, and then step 3 and step 4 are repeated until the interrupt does not happen again or all the relays transmit; if the interrupt does not happen, the relay does not transmit in the next time slot, and S sends new signal. The method has the advantage that not only the total diversity gain is achieved, but also the spectral efficiency is improved greatly.

Description

Based on the increment relay transmission method of many relayings list information source list stay of two nights collaborative network

Technical field

The present invention relates to wireless communication field, specifically a kind of increment relay transmission method based on many relayings list information source list stay of two nights collaborative network.

Background technology

As everyone knows, there is various propagation loss in wireless channel, such as path loss, multipath effect and shadow effect etc.Usually, in slow fading channel environment, if a wireless channel out of order, so in its ensuing a period of time, channel circumstance quality also can not be very good, and the probability of the bust this namely carried out during this period is very high, even if repeat to transmit identical signal.

Because wireless channel has broadcast characteristic, namely in a transmission engineering, the node in the transmission range of information source node can receive signal, and no matter it need not need.When destination node accepts unsuccessfully, other adjacent nodes may proper reception of.Therefore, if now adjacent node retransmits a signal again to destination node, then can play and well make up effect.We are referred to as cooperation transmission this, and cooperative diversity technique is proposed in 2004 years by people such as J.N.Laneman.

Cooperation transmission is also called cooperative relaying usually, namely adjacent node is regarded as a via node.There is the cooperative relaying type that two kinds common, decoding forwards (DF) and amplification forwarding (AF), K.J.R.Liu, A.K.Sadek, wait in nationality that people writes books " Cooperative Communications and Networking " and done corresponding description to two types.In DF, relaying, before forward signal, needs first to decode.And in AF, relaying only needs simply to do signal to amplify process, and do not need decoding.Therefore, the computation complexity of AF, DF of comparing is higher.So the present invention adopts AF method.

In common AF scheme, always relaying forwards, regardless of original transmitted success or not, obviously, such spectrum efficiency is very low.Propose a kind of many relayings in " Outage Analysis ofMulti-node Amplify-and-Forward Relay networks " that the people such as K.G.Seddik deliver on the Wireless Communications and Networking Conference of 2006 to forward in same time slot simultaneously, improve spectrum efficiency, but whole diversity gains can not be reached.The people such as J.N.Laneman are published in the concept proposing increment relaying (Incremental relaying) in " the Cooperative diversityin wireless networks:Efficient protocols and outage behavior " on IEEE Trans.Inf.Theory for 2004, namely relaying only just participates in when initial transmission failure forwarding, otherwise do not forward, the verified program can not only improve spectrum efficiency, and can reach very high diversity gain.

In above-mentioned several AF scheme, or only considered the situation of single relaying increment forwarding, or only consider the situation that many relaying cooperations forward.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, a kind of increment relay transmission method based on many relayings list information source list stay of two nights collaborative network is provided, in multiple single antenna via node environment, introduce increment trunking plan, thus improve the inefficient drawback of conventional multi-relay collaborative network intermediate frequency spectrum with a kind of method of simple possible.The present invention has complexity feature low, simple to operate, only need feed back a single bit of information at the end of each relay transmission, and contrast with the strategy of routine, this programme can not only reach full diversity gains, and has higher spectrum efficiency simultaneously.

For realizing above-mentioned object, the increment relay transmission method based on many relayings list information source list stay of two nights collaborative network of the present invention, whole transmitting procedure is divided into two stages, comprises the following steps:

Step 1: in first stage, information source S is to all repeat broadcast bursts;

Step 2: after all relay receptions to burst, carries out amplification process to it;

Step 3: in second stage, all relayings are forward signal sequence in sequence.

Step 4: after the stay of two nights receives i-th signal, carries out maximum-ratio combing (MRC) process to the signal of i above, then carries out interrupt event judgement;

Step 5: by result feedback to relaying and information source, if the court verdict of described step 4 is interrupt, then next relay forwarding signal, information source is kept silent, then repeat described step 4 and step 5, forward until all relayings all take part in or do not interrupt; If the court verdict of described step 4 is not for interrupt, then relaying stops forwarding, and information source sends new signal.

Preferably, in the present invention, after each relay forwarding terminates, the stay of two nights all can be done all signals received and once adjudicate, and gives each relaying R and information source S, information source S and relaying R according to feedback information result feedback, determines the action of next time slot.

Described judgement mode is as follows:

${\mathrm{\γ}}_{\mathrm{mrc}}^K=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}\left(\frac{{\mathrm{SNR}\left|h_{i,d}{\mathrm{\β}}_i{h}_{s,i}\right|}^2}{{{\mathrm{\β}}_i}^2{\left|h_{i,d}\right|}^2+1}\right)K\∈[1,n]$

Wherein for the output signal-to-noise ratio (SNR) of front K relay forwarding signal after maximum-ratio combing (MRC) receiver, h _s,ifor the channel coefficients between information source and relaying i, h _i,dfor the channel coefficients between the stay of two nights and relaying i, β _ifor the amplification coefficient of relaying i, B is single bit of information, for representing this transmission success or failure, such as, B=1 represents this transmission success, and B=0 represents bust this.

The physical significance of two formulas is above, after K relay transmission terminates, the stay of two nights carries out maximum-ratio combing (MRC) to the signal received in a front K time slot, and the signal after being combined carries out interrupt event judgement, if Average Mutual is greater than given spectrum efficiency SE, namely

$\frac{1}{K+1}\log (1+{\mathrm{\γ}}_{\mathrm{mrc}}^K)\≥\mathrm{SE}$

Then do not interrupt, stay of two nights feedback information, B=1, after receiving information, information source S transmits new signal, and relaying no longer forwards.Otherwise interrupt, stay of two nights feedback information, B=0, after receiving information, information source S does not send signal, next relay forwarding signal.

Preferably, relaying forwards successively by certain order, and described certain order to be gone on row arbitrary number for centering in advance, and do not consider the quality of channel, during forwarding, numbering is carried out from small to large successively.

Preferably, described relaying carries out amplification forwarding (AF) process, specific as follows:

x _i=β _iy _s,i i∈[1,n]

Wherein y _s,ibe the signal that i-th relay reception arrives, x _ifor transmitting after amplifying, β _ifor amplification coefficient,

${\mathrm{\β}}_i=\sqrt{\frac{P_i}{P_s{\left|h_{s,i}\right|}^2+N_0}},i\∈[1,n]$

Wherein P _ifor the transmitting power of relaying i, P _sfor the transmitting power of information source, N ₀for noise variance, h _s,ifor the channel coefficients between information source and relaying i.

Preferably, described stay of two nights end takes maximum-ratio combing technology, and the process of its process is specific as follows:

$y=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}{\mathrm{\α}}_i{y}_{i,d},K\∈[1,n]$

Wherein y _i,dfor receiving the signal from relaying i, n is total relaying number, y be merge and signal, α _iit is the weight coefficient of i-th S-R-D link

${\mathrm{\α}}_i=\frac{\sqrt{P_s}{\mathrm{\β}}_i{h}_{i,d}^{*}{h}_{s,i}^{*}}{({{\mathrm{\β}}_i}^2{\left|h_{i,d}\right|}^2+1)N_0},i\∈[1,K]$

Wherein P _sfor the transmitting power of information source, N ₀for noise variance, h _{s, i}for the channel coefficients between information source and relaying i, h _{i, d}for the channel coefficients between the stay of two nights and relaying i, β _ifor the amplification coefficient of relaying i, h ^*represent the conjugate transpose of h, K is in this transmitting procedure, participates in the relaying number forwarded.

Operation principle of the present invention is as follows:

In general collaborative network, or only consider all to participate in forward signal in each transmitting procedure of multiple relaying, or only consider the application of increment relaying in single relay cooperative network.Although the former can reach whole diversity gains, clearly, the time slot taken needed for it or frequency spectrum resource are very large, and in other words, its spectrum efficiency is low-down; The latter is owing to applying increment relaying technique, always namely relaying does not forward, as long as when in the imperfect situation of direct link, just need relay forwarding signal, therefore its spectrum efficiency is better than conventional cooperation scheme, but it does not consider the situation of multiple relaying.

Contemplated by the invention the application of increment relaying technique in many relayings list information source list stay of two nights collaborative network, transmission plan is: only have when relaying above all bust this time, just need next relaying to forward, otherwise information source directly send a new signal, carries out the transmission of next round.In the present invention after each relay transmission terminates, need to do at stay of two nights end once to adjudicate, judge whether the forward signal of this relaying can make stay of two nights end success decoded signal, and by result feedback to information source and relaying.If of course, information source sends new signal, and relaying no longer forwards; Otherwise information source does not send new signal, next signal forward signal, until all relayings all forwarded.Proved by emulation, the present invention can not only reach full diversity gains, better meets QoS(service quality) requirement, but also improve spectrum efficiency.

Accompanying drawing explanation

Fig. 1 is many relayings increment relay cooperative network topological diagram.

Fig. 2 is the particular flow sheet of transmission plan of the present invention.

Fig. 3 is the total timeslot number needed in scheme transmitting procedure of proposing of the present invention, and wherein N=2, N=4, N=6, N=8 tetra-curves represent outage probability curve corresponding to this total relaying number respectively, and in addition, in the present embodiment, we make SE=1.

Fig. 4 is corresponding different relaying number, and conventional scheme compares with the outage probability of the scheme that have employed increment relaying.

Embodiment

Below in conjunction with accompanying drawing and simulation example, embodiments of the invention are elaborated: the present embodiment is implemented under premised on technical solution of the present invention; give detailed execution mode and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

Many relayings list information source list stay of two nights trunk channel as shown in Figure 1.In emulation, forward channel and backward channel coefficients all obey independently Gaussian Profile, and average is 0, and variance is 1.In test, suppose relay has identical transmitting power, is P _s/ n, n are total relaying number.The noise of relay and stay of two nights end obeys identical distribution.The spectrum efficiency SE=1 specified.

In order to embody advantage of the present invention, the present invention and the conventional many relay transmission schemes of increment relaying technique that do not adopt contrast, the outage probability of two schemes is carried out, has also drawn the average timeslot number needed for the whole transmitting procedure of the present invention by emulation in addition.Emulation adopts Monte-Carlo emulation mode, and every prescription case all carries out 10,000 l-G simulation test.The signal received is carried out amplification forwarding by relaying.Suppose that channel is flat fading, in same once transmission, channel situation remains unchanged.As shown in Figure 2, each test is carried out according to following steps:

Step 1: in first stage, information source S is to all repeat broadcast bursts;

Step 2: after all relay receptions to burst, carries out amplification process to it;

Step 3: in second stage, all relayings are forward signal sequence in sequence.

Step 4: after the stay of two nights receives i-th signal, carries out maximum-ratio combing (MRC) process to the signal of i above, then carries out interrupt event judgement;

Step 5: by result feedback to relaying and information source, if the court verdict of described step 4 is interrupt, then next relay forwarding signal, information source is kept silent, then repeat described step 4 and step 5, forward until all relayings all take part in or do not interrupt; If the court verdict of described step 4 is not for interrupt, then relaying stops forwarding, and information source sends new signal.

The application scenarios of the present embodiment, is the many relayings list information source list stay of two nights relay cooperative network shown in accompanying drawing 1, includes 1 information source, n relaying and 1 stay of two nights in network.Information source, the stay of two nights and relaying are all single antenna.Judgement mode described in step 4, that takes in the present invention carries out interrupt event judgement, when the maximum Average Mutual namely between 2 o'clock is less than given spectrum efficiency, interrupts.Concrete grammar is as follows:

After K relay transmission is complete, the stay of two nights carries out maximum-ratio combing (MRC) to a front K signal, and the SNR obtaining the signal after merging is:

${\mathrm{\γ}}_{\mathrm{mrc}}^K=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}\left(\frac{{\mathrm{SNR}\left|h_{i,d}{\mathrm{\β}}_i{h}_{s,i}\right|}^2}{{{\mathrm{\β}}_i}^2{\left|h_{i,d}\right|}^2+1}\right)K\∈[1,n]$

Now, maximum Average Mutual is:

$I=\frac{1}{K+1}\log (1+{\mathrm{\γ}}_{\mathrm{mrc}}^K)$

Adjudicate the mutual information obtained, judgement mode is as follows

The court verdict done, the present embodiment information B of a single-bit preserves, and returns to information source and relaying.Now according to the difference of court verdict, be divided into two kinds of situations:

1. if B=1, namely adjudicate successfully, in next time slot, information source can send a new symbol, and relaying does not forward, and the stay of two nights is decoded according to a front K signal.

If 2. B=0, namely adjudicates failure, in next time slot, information source is kept silent, next relaying amplification forwarding signal, after the stay of two nights receives signal, then adjudicates---feedback, until all relayings all participate in forwarding, or till adjudicating successfully.

From accompanying drawing 3, can reach a conclusion, along with the increase of SNR, the timeslot number needed for the present invention program will greatly reduce, and also namely mean that spectrum efficiency improves greatly.From accompanying drawing 4, can reach a conclusion, compare with the scheme of routine, the present invention program also can reach full diversity gains, and its outage probability is less.

Although content of the present invention has done detailed introduction by above preferred embodiment, will be appreciated that above-mentioned description should not be considered to limitation of the present invention.After those skilled in the art have read foregoing, for multiple amendment of the present invention and substitute will be all apparent.Therefore, protection scope of the present invention should be limited to the appended claims.

Claims (1)

1. based on an increment relay transmission method for many relayings list information source list stay of two nights collaborative network, it is characterized in that: the whole transmitting procedure of described method is divided into two stages:

Step 1: in first stage, information source S is to all repeat broadcast bursts;

Step 2: after all relay receptions to burst, carries out amplification process to it;

Step 3: in second stage, all relayings are forward signal sequence in sequence;

Step 4: after the stay of two nights receives i-th signal, carries out maximum-ratio combing process to the signal of i above, then carries out interrupt event judgement;

Step 5: by result feedback to relaying and information source, if the court verdict of described step 4 is interrupt, then next relay forwarding signal, information source is kept silent, then repeat described step 4 and step 5, forward until all relayings all take part in or do not interrupt; If the court verdict of described step 4 is not for interrupt, then relaying stops forwarding, and information source sends new signal;

Via node carries out amplification forwarding process to the signal received, and described processing mode is as follows:

x _i＝β _iy _s，i i∈[1，n]

Wherein y _{s, i}be the signal that i-th relay reception arrives, x _ifor transmitting after amplifying, n is total relaying number, β _ifor amplification coefficient,

${\mathrm{\β}}_i=\sqrt{\frac{P_i}{P_s{\left|h_{s,i}\right|}^2+N_0}},i\∈[1,n]$

Wherein P _ifor the transmitting power of relaying i, P _sfor the transmitting power of information source, N ₀for noise variance, h _{s, i}for the channel coefficients between information source and relaying i;

Relaying forwards successively by certain order, and described certain order to be gone on row arbitrary number for centering in advance,

Do not consider the quality of channel, during forwarding, numbering is carried out from small to large successively;

The process of described maximum-ratio combing process is specific as follows:

$y=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}{\mathrm{\α}}_i{y}_{i,d},K\∈[1,n]$

Wherein y _{i, d}for receiving the signal from relaying i, n is total relaying number, y be merge and signal, α _iit is the weight coefficient of i-th S-R-D link

${\mathrm{\α}}_i=\frac{\sqrt{P_s}{\mathrm{\β}}_i{h}_{i,d}^{*}{h}_{s,i}^{*}}{({{\mathrm{\β}}_i}^2{\left|h_{i,d}\right|}^2+1)N_0},i\∈[1,K]$

Wherein P _sfor the transmitting power of information source, N ₀for noise variance, h _{s, i}for the channel coefficients between information source and relaying i, h _{i, d}for the channel coefficients between the stay of two nights and relaying i, β _ifor the amplification coefficient of relaying i, h ^*represent the conjugate transpose of h, K is in this transmitting procedure, participates in the relaying number forwarded;

After receiving the signal that relay forwarding comes, the stay of two nights is interrupted the signal received above at every turn

Judgement, concrete judgement mode is as follows:

${\mathrm{\γ}}_{\mathrm{mrc}}^K=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}\left(\frac{\mathrm{SNR}{\left|h_{i,d}{\mathrm{\β}}_i{h}_{s,i}\right|}^2}{{{\mathrm{\β}}_i}^2{\left|h_{i,d}\right|}^2+1}\right)K\∈[1,n]$

Wherein for the output signal-to-noise ratio of front K relay forwarding signal after maximum-ratio combing receiver, h _{s, i}for the channel coefficients between information source and relaying i, h _{i, d}for the channel coefficients between the stay of two nights and relaying i, β _ifor the amplification coefficient of relaying i, B is single bit of information, for representing this transmission success or failure.