CN103634040A - Communication method and apparatus for relay network - Google Patents

Abstract

The invention provides a communication method and apparatus for relay network. The relay network includes a source node, a target node and a plurality of relay nodes. The method comprises the following steps that: pilot frequency information sent by each candidate relay node is received at the target node at one time slot, wherein the pilot frequency information at least includes first channel state information from the source node to corresponding candidate relay nodes; second channel state information from each of the candidate relay nodes to the target node is obtained; an optimum relay node is selected from the candidate relay nodes at least based on the first channel state information and the second channel state information; and a message that is received from the source node by the optimum relay node at a time slot previous to the time slot is forwarded. Moreover, on the basis of the precoding design of the source node and the relay nodes, interferences caused by other relays and the adjacent interference source can be eliminated, thereby further improving the system performance.

Description

Communication means and device for junction network

Technical field

The present invention relates to communication system, and more specifically, relate to the communication means based on single time slot relay selection and device in the junction network of communication system.

Background technology

Relaying is communication system, comprise technology conventional in wireless and wired communication system.In recent years, relaying has become one of core technology in the senior Long Term Evolution of 3GPP (LTE-A) system.Relaying not only has the ability that extended network covers, but also can improve the capacity of network, utilizes the feature that relaying cost is low can reduce network construction cost simultaneously.By disposing via node at cell edge, Cell Edge User can be experienced the received signal power from the raising of service via node, thereby can improve the throughput of Cell Edge User.The current difference according to relaying execution function can be divided into relaying layer one relaying, layer two relaying and layer three relaying.Layer one relaying is the relaying of amplification forwarding (AF) type.

At present, the relaying strategy for AF relay system is conducted extensive research, but be mainly conceived to ideal system structure for the research work aspect the relay selection in this relay system, and do not consider the presence of intercell interference in collaborative processes.And in fact, presence of intercell interference has significant impact for the signal interference plus noise of traditional AF relaying than (SINR) performance.And all based on two slot transmission, because will use two time slots, therefore this relay selection based on two slot transmission can reduce the total rate capability of system undoubtedly for the relay selection of existing AF junction network.

Summary of the invention

In order to solve the above-mentioned problems in the prior art, embodiments of the present invention have proposed the relay communication method based on single time slot relay selection and the device for the system of limit interferences.

According to an aspect of the present invention, a kind of communication means for junction network is provided, this junction network comprises source node, destination node and a plurality of via node, the method is included in a time slot: at destination node place, receive the pilot frequency information that each candidate relay node sends, this pilot frequency information at least comprises the first channel condition information from source node to corresponding candidate via node; Acquisition is from each second channel state information to destination node of candidate relay node; At least based on the first channel condition information and second channel state information, from candidate relay node, select optimal relay node; And receive from optimal relay node the message that it receives from source node in time slot.

According to a further aspect in the invention, provide a kind of trunking method for junction network, this junction network comprises source node, destination node and a plurality of via node, and the method comprises: in a time slot, in the message of both candidate nodes place reception sources node broadcasts; And in the next time slot of this time slot: in both candidate nodes, place sends pilot frequency information to destination node, this pilot frequency information at least comprises the first channel condition information from source node to corresponding via node; Receive the message that destination node is broadcasted, this message at least comprises the information which via node to be selected as optimal relay node about; And this optimal relay node receives it in upper time slot message from source node is forwarded to destination node.

According to another aspect of the invention, a kind of communicator for junction network is provided, this junction network comprises source node, destination node and a plurality of via node, this communicator is used in destination node place, comprise: receiving element, be arranged to and receive the pilot frequency information that each candidate relay node sends, this pilot frequency information at least comprises the first channel condition information from source node to corresponding candidate via node; And in a time slot, from optimal relay node, receive the message that it receives from source node in time slot; And processing unit, be arranged to each the second channel state information to destination node obtaining from candidate relay node; And at least based on the first channel condition information and second channel state information, from candidate relay node, select optimal relay node.

According to another aspect of the invention, a kind of relay for junction network is provided, this junction network comprises source node, destination node and a plurality of via node, this relay is used in each via node place, comprise: transmitting element, be arranged to destination node and send pilot frequency information, this pilot frequency information at least comprises the first channel condition information of corresponding via node from source node to relay; And if the corresponding via node of relay is selected as optimal relay node at a time slot, in this time slot, to destination node, forward the message that it receives from source node in a upper time slot; And receiving element, be arranged to from source node receipt message; And receive the message that destination node is broadcasted, this message at least comprises the information which via node to be selected as optimal relay node about.

Accompanying drawing explanation

By reference to the accompanying drawings, foregoing invention content of the present invention and other side, feature and advantage will become clearer the detailed description of the non-limiting example from following, wherein:

Fig. 1 shows the schematic diagram of the double bounce amplification forwarding junction network of prior art;

Fig. 2 shows according to the schematic diagram of the junction network of exemplary embodiment of the invention;

Fig. 3 shows according to the schematic time slot map of the relay communication method based on single time slot relay selection of exemplary embodiment of the invention;

Fig. 4 shows according to the flow chart of the relay communication method based on single time slot relay selection of exemplary embodiment of the invention;

The destination node place that Fig. 5 shows in junction network carries out according to the flow chart of the method for exemplary embodiment of the invention;

Fig. 6 shows according to the flow chart of the interference alignment algorithm of the allied signal of exemplary embodiment of the invention;

Fig. 7 shows according to the structured flowchart of the relay for junction network of exemplary embodiment of the invention;

Fig. 8 shows according to the structured flowchart of the communicator for junction network of exemplary embodiment of the invention.

Embodiment

Below with reference to accompanying drawing, illustrative embodiments of the present invention is described.In this illustrative embodiments, take LTE system as example.But those skilled in the art are to be understood that; scope of the present invention is not limited to this; this illustrative embodiments is only for describing object; should be regarded as example of the present invention but not any limitation of the invention, any scheme of exemplary embodiment of the invention of having utilized all falls within the scope of protection of the present invention.

Fig. 1 shows the schematic diagram of the double bounce amplification forwarding junction network of prior art.This junction network 100 comprises source node, via node and destination node.Source node is base station normally, such as the NodeB in LTE or eNB etc., but the invention is not restricted to this.Destination node is subscriber equipment normally, can be for example, fixing or mobile phone, desk-top or portable computer, personal digital assistant (or PDA), the game console that may become communication equipment, the household electrical appliance that may become communication equipment, the television set that may become communication equipment or multimedia content receivers (such as STB or " Set Top Box ") etc., but the invention is not restricted to this.In this communication network 100, the link from source node to via node is commonly called the first hop link, and the link from via node to destination node is commonly called the second hop link.

Exemplary embodiment of the invention has proposed a kind of communication means based on single time slot relay selection for double bounce junction network, and the method has been considered the interference from neighbor cell simultaneously, can effectively suppress to disturb and improve system spectral efficiency.Fig. 2 shows according to the schematic diagram of the junction network 200 of exemplary embodiment of the invention, and its small area C is relaying enhancement type district, the interfered cell of ，Ji community, the neighbor cell C that C ’Shi Yu community, community C is adjacent.Junction network 200 by have M root antenna source node S, there is the destination node D of N root antenna and K that disperse and fixing via node forms, wherein each via node has L root antenna, the auxiliary transmission from source node S to destination node D of this K via node.Here, suppose does not have direct link between source node S and destination node D, all transmission all will be via the first hop link from source node S to via node and the second hop link from via node to destination node D, and at via node and destination node D place, can obtain respectively the first hop channel state information (CSI) and the second jumping CSI, and K the via node disperseing can be processed and this message is forwarded to destination node D to the message receiving from source node S.For the object clearly demonstrating, also suppose that interfered cell C ' is used from disturbing source node S herein ' to the direct transmission of destination, this destination can be via node, destination node D or other destination nodes.

The design philosophy of the communication means based on single time slot relay selection that exemplary embodiment of the invention proposes comprises:

(1) source node in first time slot to the via node broadcast transmission message of all dispersions;

(2) then,, since each time slot of second time slot, (that is, may be selected as the via node of optimal relay node in this time slot, the in the situation that of second time slot, candidate relay node is all via nodes to each candidate relay node; In the situation that being greater than the second time slot, candidate relay node is all via nodes except selecteed optimal relay node in a upper time slot) by pilot tone, to destination node, send comprise the first hop channel state information, about the information of the interference from neighbor cell and the information that sends request (RTS) of a bit, this pilot transmission can be ignored taking of time slot;

(3) after the pilot frequency information detecting from each candidate relay node, the double bounce channel condition information of the relay selection method (being below described in greater detail) that destination node use exemplary embodiment of the invention proposes based on combination selects optimal relay node to assist the transmission from source node to destination node, and to each candidate relay node, notify this via node whether to be selected as optimal relay node by broadcast, this broadcast feedback can be ignored taking of time slot;

(4) selected optimal relay node sends to destination node by the message receiving from source node in a upper time slot, and in the same time slot sending at selected via node, source node is to the next message of all via node broadcast transmissions;

(5) due to the half-duplex character of via node, selected optimal relay node is when sending to destination node, can not receive source node in (4) and in this time slot, broadcast to the message of all via nodes, therefore can not be as the candidate relay node of next slot transmission.

Fig. 3 and Fig. 4 describe the relay communication method based on single time slot relay selection according to exemplary embodiment of the invention in detail.In Fig. 3, " √ " represents that via node receives the message sending from source node at this time slot, " Tx " represents that via node does not receive the message that source node S sends to destination node D forwarding messages at this time slot, " X " represent via node at this time slot not as candidate relay node.

Fig. 4 shows according to the flow chart of the relay communication method based on single time slot relay selection of exemplary embodiment of the invention.As shown in Figure 4, in step 401, in first time slot, source node S sends message to K via node of all dispersions.Then, in step 402, in second time slot, each via node by pilot frequency information, to destination node D, send comprise the first jumping CSI, about the information of the information of the interference from neighbor cell C ' and the RTS of a bit, destination node D combines the first CSI that jumps CSI and local acquisition obtaining from pilot frequency information, to obtain the CSI of combination.In one embodiment, destination node D can obtain the first hop channel gain from the CSI of pilot frequency information, and by itself and local the second hop channel gain combination obtaining, to obtain the channel gain of combination.In another execution mode, destination node D can calculate the reception signal noise ratio (SNR) of the first jumping by the CSI based on obtaining from pilot frequency information, and is combined with the second reception SNR jumping of local computing.Afterwards, destination node D can based on combination CSI, in one embodiment, channel gain based on combination, in another execution mode, at least the reception SNR based on double bounce selects optimal relay node m in all K via node, and to all K via node notice via node m, has been selected as optimal relay node by broadcast.In step 402, selected optimal relay node m is forwarded to destination node D by the message receiving in first time slot but is not received in the message that this time slot sends from source node S, in second time slot, other non-selected via nodes stop forwarding for the message of destination node D, and are received in the message that this time slot sends from source node S.In step 403, at T time slot (T > 2), except be selected as all via nodes optimal relay node in a upper time slot, be that candidate relay node sends pilot frequency information to destination node D, destination node D selects optimal relay node m and to destination node D, forwards the message that it receives in a upper time slot by this optimal relay node m in these candidate relay nodes, and in current time slots, selected optimal relay node m is not received in the message that this time slot sends from source node S.In step 404, judge whether source node S has sent all message that will send, if the determination result is NO, flow process turns back to step 403, continue by source node S transmission message and by selected optimal relay node forwarding messages; If judgment result is that to be, so in the end, in a time slot, source node S stops sending, and selected optimal relay node m forwards last message to destination node D, and so far this flow process finishes.

The destination node D place that Fig. 5 shows in junction network carries out according to the flow chart of the method for exemplary embodiment of the invention.First, in step 501, in the individual time slot of T (T >=2), destination node D receives pilot frequency information from each candidate relay Nodes, therefrom obtains the first hop channel state information from source node S to each candidate relay node.In step 502, destination node D obtains the second hop channel state information from each candidate relay node to himself.Next, in step 503, destination node D jumps state information based on the first jumping state information and second and selects optimal relay node m.Herein, when T=2, each candidate relay node comprises all K via node, and when T > 2, each candidate relay node comprises K-1 via node the optimal relay node except selecting in T-1 time slot.Afterwards, in step 504, destination node D can receive the message that it receives from source node S at time slot from optimal relay node.Then in step 505, judge whether to have received all message, if so, flow process finishes, and if not, returns and proceeds to process.

In description above, only provided and carried out according to the exemplary order of the method step of embodiment of the present invention, but the order of carrying out the method step is not limited to this, the any execution order that can realize embodiment of the present invention, within comprising that conversion between above-mentioned steps, combination all fall into scope of the present invention.

To describe in detail according to the relay selection method under an exemplary embodiment of the present invention below.Suppose at each via node, interfere information and the calculating that can obtain from neighbor cell C ' receive SINR, and interfere information and the calculating that at destination node D place, also can obtain from neighbor cell C ' receive SINR.At destination node D place, with following algorithm, select optimal relay node.

This algorithm is based on following thought:, if carry out double bounce relay transmission by optimal relay node, the reception signal noise ratio (SNR) obtaining at optimal relay node place so and the minimum SNR in the reception SNR of destination node place acquisition are maximum with the ratio of the reception SNR of the interference from interference source obtaining at destination node place, and this trunk node selection standard can be expressed as:

$m=\underset{k}{\arg \max }\left\{\frac{\min \{{\mathrm{\γ}}_{s,k},{\mathrm{\γ}}_{k,D}\}}{{\mathrm{\γ}}_{s^{\′},k}}\right\}(k=1,...,K)---\left(1\right),$

Wherein, γ _{s, k}the signal noise ratio (SNR) of expression from source node S to k via node, γ _{k, D}represent that k via node is to the SNR of destination node D, γ _{s ', k}the interference source S ' of expression from the C ' of neighbor cell is to the SNR of k via node.

In order further to reduce the impact from the interference of neighbor cell, embodiment of the present invention has also proposed after having selected optimal relay node, source node S and selected optimal relay node m is carried out to the interference registration process of allied signal.

Disturbing the basic thought of aiming at is that receipt message spatial division is become to two independently subspaces, i.e. signal subspace and interference space.The performance of this scheme is directly determined by the distance between two sub spaces.At each receiver place, interference signal is being carried out after ZF (ZF) processing, in order to obtain, receive SINR maximization, make as much as possible useful signal and interference space quadrature.

In order to promote and to receive SINR as much as possible, embodiment of the present invention has proposed a kind of interference alignment algorithm of allied signal.The basic thought of this algorithm is: at receiving node place, make to fall into as much as possible signal subspace from the signal of source node,, the signal strength signal intensity that makes to fall into signal subspace is large and to make to fall into the signal strength signal intensity of interference space as much as possible little as much as possible, makes the signal that becomes interference as far as possible all fall into interference space simultaneously.In this algorithm, by adjusting following expression formula (2) with weighting parameters ω, so that it maximizes, when expression formula (2) is maximum, the reception SINR at receiving node place reaches maximum:

$H_{m,k}{V}_m{V}_m^H{H}_{m,k}^H+H_{S^{\′},k}{V}_{S^{\′}}{V}_{S^{\′}}^H{H}_{S^{\′},k}^H-\mathrm{\ω}{H}_{S,k}{V}_S{V}_S^H{H}_{S,k}^H---\left(2\right),$

Wherein, H _{s, k}and H _{s ', k}respectively source node S and interference source S ' to k (k=1 ..., K, k ≠ m) and the channel matrix of individual via node, H _{m, k}for the channel matrix of selected optimal relay node m to k non-selected via node, V _s, V _{s '}and V _mrespectively the pre-coding matrix of source node S, interference source S ' and selected optimal relay node m,

deng in H represent conjugate transpose.Therefore, interference space U _kcolumn vector be L-d the main characteristic vector of expression formula (2),, characteristic vector corresponding to a maximum L-d characteristic value, to meet the requirement that makes SINR maximum, wherein L is the antenna number of via node, it equals the characteristic value number of expression formula (2), and d is the data flow number of system transmission, and it equals V _mcolumns.

The pre-coding matrix of source node S and selected optimal relay node m is designed to the interference that source node S and via node m cause at non-selected via node place falls into interference space U _k, k ≠ m, and the signal receiving at selected via node m place is fallen into and U as far as possible _kthe subspace of quadrature.Accordingly, the pre-coding matrix V of selected optimal relay node m _mcan be confirmed as:

$V_m=\underset{{\hat{V}}_m}{\arg \min }\underset{k=1,k\≠m}{\overset{K}{\mathrm{\Σ}}}{\left|\right|H_{m,k}{\hat{V}}_m,U_k\left|\right|}_M^2---\left(3\right).$

Can obtain thus the optimum transmission pre-coding matrix V in selected optimal relay node m place _mrow be

d non-master (least dominant) characteristic vector, that is, and corresponding to the characteristic vector of a minimum d characteristic value.Similarly, use and select V _msimilar technology, the pre-coding matrix V of source node S _scan be confirmed as:

$V_S=\underset{{\hat{V}}_S}{\arg \min }\underset{k=1,k\≠m}{\overset{K}{\mathrm{\Σ}}}{\left|\right|H_{S,k}{\hat{V}}_S,U_k^{\⊥}\left|\right|}_M^2---\left(4\right).$

Can obtain thus the transmission pre-coding matrix V of source node S place optimum _sclassify as

d non-main characteristic vector.

Fig. 6 shows according to the flow chart of the interference alignment algorithm of the allied signal of an exemplary embodiment of the present invention.First, in step 601, in T time slot (T>=2), destination node D selects optimal relay node m by equation (1), and each via node except optimal relay node m obtains the pre-coding matrix V of neighbor cell C ' _{s '}.Afterwards in step 602, respectively at via node m and source node S place initialization pre-coding matrix V _mand V _s.Then, in step 603, each non-selected via node is determined its interference space U _k(k=1 ..., K, k ≠ m), U _krow by the L-d of expression formula (2) main characteristic vector, formed.Afterwards, in step 604, via node m and source node S are used the U obtaining from step 603 _kby equation (3) and (4), upgrade pre-coding matrix V _mand V _s.Then, in step 605, the pre-coding matrix V that judgement is upgraded in step 604 _mand V _sand whether the distance between the pre-coding matrix obtaining in last iteration is in predetermined threshold range, and this threshold value is for example 0.001.If judgment result is that of step 605 is to illustrate V _mand V _siterative computation restrain, the calculating that therefore enters next time slot in step 606, flow process is returned to step 601.If the determination result is NO for step 605, illustrate V _mand V _salso convergence of iterative computation, so flow process returns to step 603, utilizes the pre-coding matrix V upgrading _mand V _sby expression formula (2), redefine the interference space U of non-selected via node _kuntil obtain stable V _mand V _s.

According to exemplary embodiment of the invention, in each time slot, after having selected optimal relay node, all carry out the interference registration process of allied signal at every turn, can more effectively suppress thus to disturb to obtain maximum reception SINR.

Exemplary embodiment of the invention also provides a kind of relay 700 for junction network.Referring to Fig. 7, Fig. 7 shows according to the structured flowchart of the relay for junction network of exemplary embodiment of the invention.As shown in Figure 7, this relay 700 comprises: memory cell 701, storage is for carrying out according to program and the data of the interference alignment algorithm of the allied signal of exemplary embodiment of the invention, and realize according to other necessary program and the data of the method for embodiment of the present invention, memory cell 701 also can be used as to be sent and buffer received signal; Processing unit 702, aims at relevant processing with the interference of allied signal and realizes other necessary processing the according to the method for embodiment of the present invention carrying out for the program of carrying out memory cell 701 storage; Receiving element 703, for receiving signal, for example, for from source node receipt message and receive from the message of destination node broadcast; Transmitting element 704, for transmitted signal, for example, sends pilot frequency information to destination node, forwards the message that it receives from source node in a upper time slot in a time slot to destination node.

Exemplary embodiment of the invention also provides a kind of communicator 800 for junction network.Referring to Fig. 8, Fig. 8 shows according to the structured flowchart of the communicator of exemplary embodiment of the invention.This communicator can be for example subscriber equipment.As shown in Figure 8, this communicator 800 comprises: memory cell 801, storage is for carrying out according to the program of the relay selection algorithm of exemplary embodiment of the invention and data, and realize according to other necessary program and the data of the method for embodiment of the present invention, memory cell 801 also can be used as to be sent and buffer received signal; Processing unit 802, for carrying out the program of memory cell 801 storages, to carry out the processing relevant with relay selection and realization, according to other necessity of the method for embodiment of the present invention, process, for example,, for obtaining each the second channel state information to destination node from candidate relay node; And at least based on the first channel condition information and second channel state information, from candidate relay node, select optimal relay node; Receiving element 803 for receiving signal, for example, for each the reception pilot frequency information from candidate relay node, and receives the message that it receives from source node in time slot in a time slot from optimal relay node; Transmitting element 804, for transmitted signal, for example, sends broadcast to via node.

Memory cell 701,801 can be one or more memories, and there is any type that is applicable to local applied environment, and can realize by any suitable volatibility or nonvolatile data storage technology, such as storage component part, magnetic memory device and system, optical memory device and system, read-only storage and the removable memory of based semiconductor.The program being stored in memory cell 701,801 can comprise program command or computer program code, and program command or computer program code, when being carried out by relevant treatment unit, make device 700,800 can carry out task described herein.

Processing unit 702,802 can have any type that is applicable to local applied environment, and can comprise one or more in all-purpose computer, special-purpose computer, microprocessor, digital signal processor (" DSP "), field programmable gate array (" FPGA "), application-specific integrated circuit (ASIC) (" ASIC ") and the processor based on multi-core processor framework as non-restrictive example.

The description done by reference to the accompanying drawings is above exemplary providing for the present invention is described.It will be appreciated by those skilled in the art that, can different structures be proposed based on principle of the present invention described above, although these different structures are not clearly described herein or are illustrated, within all having embodied principle of the present invention and being included in its spirit and scope.In addition, all examples of herein mentioning are main only for instructing object to help the design of reader understanding's principle of the present invention and promotion this area that inventor was contributed clearly, should not be interpreted as limitation of the scope of the invention.In addition, all statement and specific examples thereof of mentioning principle of the present invention, aspect and execution mode comprise its equivalent interior herein.

Claims (27)

1. for a communication means for junction network, described junction network comprises source node, destination node and a plurality of via node, and described method comprises:

In a time slot:

At described destination node place, receive the pilot frequency information that each candidate relay node sends, wherein said pilot frequency information at least comprises the first channel condition information from described source node to corresponding candidate via node;

Acquisition is from each second channel state information to described destination node of described candidate relay node;

At least based on described the first channel condition information and described second channel state information, from described candidate relay node, select optimal relay node; And

Receive the message that described optimal relay node receives from described source node in a upper time slot of a described time slot.

2. method according to claim 1, wherein, for the described candidate relay node of a time slot comprise described a plurality of via nodes, all via nodes except selected optimal relay node in a upper time slot of a described time slot, and if a described upper time slot is first time slot, described candidate relay node comprises all described a plurality of via nodes.

3. method according to claim 1, wherein, from described candidate relay node, select optimal relay node to comprise: from described the first channel condition information and described second channel state information, to obtain respectively the first channel gain and second channel gain, and at least based on described the first channel gain and the gain of described second channel, from described candidate relay node, select described optimal relay node.

4. method according to claim 1, wherein, from described candidate relay node, select optimal relay node to comprise: according to described the first channel condition information and described second channel state information, to obtain the first reception signal noise ratio and the second reception signal noise ratio, and at least based on described the first reception signal noise ratio and described the second reception signal noise, recently from described candidate relay node, select described optimal relay node.

5. method according to claim 1, wherein, described pilot frequency information also comprises about the interfere information from interference source node.

6. method according to claim 5, wherein, from described candidate relay node, select optimal relay node to comprise: according to described the first channel condition information and described second channel state information, to obtain the first reception signal noise ratio and the second reception signal noise ratio, according to the information of the described interference about interference source node, obtain the 3rd and receive signal noise ratio, and receive signal noise and recently from described candidate relay node, select described optimal relay node based on described the first reception signal noise ratio, described the second reception signal noise ratio and the described the 3rd.

7. method according to claim 6, wherein, realizes the selection of described optimal relay node by following formula:

$m=\underset{k}{\arg \max }\left\{\frac{\min \{{\mathrm{\γ}}_{s,k},{\mathrm{\γ}}_{k,D}\}}{{\mathrm{\γ}}_{s^{\′},k}}\right\}(k=1,...,K),$

Wherein, γ _{s, k}the reception signal noise ratio of expression from described source node to k via node, γ _{k, D}the reception signal noise ratio of expression from k via node to described destination node, γ _{s ', k}the reception signal noise ratio of expression from described interference source node to k via node, K represents the number of described a plurality of via nodes.

8. method according to claim 1, wherein, described destination node is notified selected optimal relay node by broadcast to described a plurality of via nodes.

9. for a trunking method for junction network, described junction network comprises source node, destination node and a plurality of via node, and described method comprises:

In a time slot, at each candidate relay Nodes, receive the message of described source node broadcast; And

In the next time slot of a described time slot:

Described in each, candidate relay Nodes sends pilot frequency information to described destination node, and wherein said pilot frequency information at least comprises the first channel condition information from described source node to corresponding via node;

Reception is from the message of described destination node broadcast, and described message at least comprises the information which via node to be selected as optimal relay node about; And

Selected optimal relay node receives it in upper time slot message from described source node is forwarded to described destination node.

10. method according to claim 9, wherein, for the described candidate relay node of a time slot comprise described a plurality of via nodes, the via node except selected optimal relay node in a upper time slot of a described time slot, and if a described upper time slot is first time slot, described candidate relay node comprises all described a plurality of via nodes.

11. methods according to claim 9, wherein, described optimal relay node does not receive the message from described source node the time slot that forwards the message receiving from described source node to described destination node.

12. methods according to claim 9, further comprise:

The via node place that is not selected as optimal relay node in described a plurality of via nodes carries out the interference registration process of allied signal.

13. methods according to claim 12, the interference registration process of wherein said allied signal comprises the interference space of determining non-selected via node by following formula:

$H_{m,k}{V}_m{V}_m^H{H}_{m,k}^H+H_{S^{\′},k}{V}_{S^{\′}}{V}_{S^{\′}}^H{H}_{S^{\′},k}^H-\mathrm{\ω}{H}_{S,k}{V}_S{V}_S^H{H}_{S,k}^H---\left(1\right)$

Wherein, m represents the numbering of selected optimal relay node, and k represents the numbering of any via node except selected optimal relay node, H _{s, k}the channel matrix that source node arrives any via node except selected optimal relay node, H _{m, k}that selected optimal relay node is to the channel matrix of other any via node, H _{s ', k}that interference source node is to the channel matrix of any via node except selected optimal relay node, V _sand V _{s '}be respectively the pre-coding matrix of source node and interference source node, ω is weight coefficient,

Wherein, described interference space U _kcolumn vector be and L-d eigenvalue of maximum characteristic of correspondence vector of expression formula (1), wherein L is the characteristic value number of expression formula (1), d is V _mcolumn vector number.

14. methods according to claim 13, the matrix V that prelists of wherein said source node _sthe matrix V that prelists with selected optimal relay node _mby following two equatioies, determined:

$V_S=\underset{{\hat{V}}_S}{\arg \min }\underset{k=1,k\≠m}{\overset{K}{\mathrm{\Σ}}}{\left|\right|H_{S,k}{\hat{V}}_S,U_k^{\⊥}\left|\right|}_M^2$

$V_m=\underset{{\hat{V}}_m}{\arg \min }\underset{k=1,k\≠m}{\overset{K}{\mathrm{\Σ}}}{\left|\right|H_{m,k}{\hat{V}}_m,U_k\left|\right|}_M^2.$

15. 1 kinds of communicators for junction network, described junction network comprises source node, destination node and a plurality of via node, and described communicator is used in described destination node place, and described communicator comprises:

Receiving element, described receiving element is arranged to and receives the pilot frequency information that each candidate relay node sends, and wherein said pilot frequency information at least comprises the first channel condition information from described source node to corresponding candidate via node; And in a time slot, from optimal relay node, receive the message that it receives from described source node in time slot;

Processing unit, described processing unit is arranged to each the second channel state information to described destination node obtaining from described candidate relay node; And at least based on described the first channel condition information and described second channel state information, from described candidate relay node, select described optimal relay node.

16. communicators according to claim 15, wherein, for the candidate relay node of a time slot comprise described a plurality of via nodes, all via nodes except selected optimal relay node in a upper time slot of a described time slot, if and wherein a described upper time slot is first time slot, described candidate relay node comprises all described a plurality of via nodes.

17. communicators according to claim 15, wherein, described processing unit is further arranged to: from described the first channel condition information and described second channel state information, obtain respectively the first channel gain and second channel gain, and at least based on described the first channel gain and the gain of described second channel, from described candidate relay node, select described optimal relay node.

18. communicators according to claim 15, wherein, described processing unit is further arranged to: according to described the first channel condition information and described second channel state information, obtain the first reception signal noise ratio and the second reception signal noise ratio, and at least based on described the first reception signal noise ratio and described the second reception signal noise, recently from described candidate relay node, select described optimal relay node.

19. communicators according to claim 15, wherein, described pilot frequency information also comprises the information about the interference from interference source node.

20. communicators according to claim 19, wherein, described processing unit is further arranged to: according to described the first channel condition information and described second channel state information, obtain the first reception signal noise ratio and the second reception signal noise ratio, according to the described information about the interference from interference source node, obtain the 3rd and receive signal noise ratio, and receive signal noise and recently from described candidate relay node, select described optimal relay node based on described the first reception signal noise ratio, described the second reception signal noise ratio and the described the 3rd.

21. communicators according to claim 20, wherein, described processing unit is further arranged to the selection that realizes described optimal relay node by following formula:

$m=\underset{k}{\arg \max }\left\{\frac{\min \{{\mathrm{\γ}}_{s,k},{\mathrm{\γ}}_{k,D}\}}{{\mathrm{\γ}}_{s^{\′},k}}\right\}(k=1,...,K)$

Wherein, γ _{s, k}the reception signal noise ratio of expression from described source node to k via node, γ _k.Drepresent that k via node is to the reception signal noise ratio of described destination node, γ _{s ', k}the reception signal noise ratio of expression from described interference source node to k via node, K represents the number of described a plurality of via nodes.

22. communicators according to claim 15, further comprise transmitting element, and described transmitting element is arranged to described a plurality of via nodes and sends broadcast to notify selected optimal relay node.

23. 1 kinds of relays for junction network, described junction network comprises source node, destination node and a plurality of via node, and described relay is used in via node place described in each, and described relay comprises:

Transmitting element, described transmitting element is arranged to described destination node and sends pilot frequency information, and wherein said pilot frequency information at least comprises the first channel condition information from described source node to the corresponding via node of described relay; And if the corresponding via node of described relay is selected as optimal relay node, the message receiving from described source node in a upper time slot to described destination node forwarding in this time slot in a time slot; And

Receiving element, described receiving element is arranged to from described source node receipt message; And receive from the message of described destination node broadcast, described message at least comprises the information which via node to be selected as optimal relay node about.

24. relays according to claim 23, wherein, described receiving element is further configured to, if the corresponding via node of described relay is selected as optimal relay node in a time slot, in this time slot, does not receive the message from described source node.

25. relays according to claim 23, further comprise processing unit, described processing unit is configured to, if the corresponding via node of described relay is not selected as optimal relay node in a time slot, in this time slot, carries out the interference registration process of allied signal.

26. relays according to claim 25, described processing unit is further configured to, and when the corresponding via node of described relay is not selected as optimal relay node, by following formula, determines interference space:

$H_{m,k}{V}_m{V}_m^H{H}_{m,k}^H+H_{S^{\′},k}{V}_{S^{\′}}{V}_{S^{\′}}^H{H}_{S^{\′},k}^H-\mathrm{\ω}{H}_{S,k}{V}_S{V}_S^H{H}_{S,k}^H---\left(2\right)$

Wherein, m represents the numbering of selected optimal relay node, and k represents the numbering of any via node except selected optimal relay node, H _{s, k}the channel matrix that source node arrives any via node except selected optimal relay node, H _{m, k}that selected optimal relay node is to the channel matrix of other any via nodes, H _{s ', k}that interference source node is to the channel matrix of any via node except selected optimal relay node, V _sand V _{s '}be respectively the pre-coding matrix of source node and interference source node, ω is weight coefficient,

Wherein, described interference space U _kcolumn vector be L-d the eigenvalue of maximum characteristic of correspondence vector with expression formula (2), the characteristic value number of L expression formula (2) wherein, d is V _mcolumn vector number.

27. relays according to claim 26, described processing unit is further configured to, and when the corresponding via node of described relay is not selected as optimal relay node, determines the matrix V that prelists of described source node by following two equatioies _sthe matrix V that prelists with selected optimal relay node _m:

$V_S=\underset{{\hat{V}}_S}{\arg \min }\underset{k=1,k\≠m}{\overset{K}{\mathrm{\Σ}}}{\left|\right|H_{S,k}{\hat{V}}_S,U_k^{\⊥}\left|\right|}_M^2$

$V_m=\underset{{\hat{V}}_m}{\arg \min }\underset{k=1,k\≠m}{\overset{K}{\mathrm{\Σ}}}{\left|\right|H_{m,k}{\hat{V}}_m,U_k\left|\right|}_M^2.$

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