CN101931438B - Cooperative node selection method and device - Google Patents

Abstract

The invention provides a cooperative node selection method and a device, which are used for selecting a more reasonable cooperative node, and the method comprises the following steps: obtaining data sending power of a source node, channel gain from the source node to a destination node, available power of a first node, noise power of a channel, the channel gain from the source node to the first node and the channel gain from the destination node to the first node, wherein the first node is the potential cooperative node; determining SNR of the first node under AF mode, or the SNR under DF mode, or the SNR under the AF mode and the DF mode according to obtained information; and determining that the first node is the cooperative node of this communication if the SNR which corresponds to the first node or the maximum value in the SNRs is the maximum value in the SNRs which correspond to all the potential cooperative nodes. The adoption of the technical scheme can well meet the effective selection of the cooperative node under multi-user multi-service parallel transmission and reduce the situation that the effective cooperative transmission can not be carried out due to insufficient resources of the cooperative node.

Description

A kind of cooperative node selection method and device

Technical field

The present invention relates to communication technical field, relate in particular to a kind of cooperative node selection method, device, relay station and base station.

Background technology

In order to adapt to the future broadband wireless communication systems High Data Rate, the basic demand of high real-time and low error rate, some new technology are introduced in wireless communication system, and collaboration communication is exactly one of them.

Collaboration communication as a kind of effective opposing wireless channel decline and instable means, has launched research widely in academia and industrial quarters in recent years.The space diversity gain that is provided by cooperative node is provided its performance gain that brings, thereby improves the reliability of sourcesink node communication.From the angle of power system capacity, the lifting of communication reliability between source node and destination node makes communication to adopt higher speed to transmit under certain error rate requires, thereby improves the whole volume of system.

Collaboration communication has various ways, and wherein the most frequently used a kind of form is carried out relay transmission as cooperative node to data for select one in the potential cooperative node around source node.Destination node can receive from source node with from the two paths of signals of cooperative node, and destination node can merge by the modes such as MRC to two paths of signals, the information of efficient decoding source node.Because the transmitted signal of the transmitted signal of source node and cooperative node has separately independently decline, destination node merges this two paths of signals with certain criterion, thereby obtains space diversity gain.

In the junction network of infrastructure is arranged, may there be a plurality of potential cooperative nodes to exist, therefore, suitable cooperative node of How to choose source node that cooperates transmits, and is technical issues that need to address.

Summary of the invention

The embodiment of the present invention provides a kind of cooperative node selection method and device, select in order to carry out cooperative node in conjunction with the available resources of potential cooperative node itself, thereby can in the situation that a plurality of potential cooperative nodes are arranged, select a suitable potential cooperative node to communicate.

The embodiment of the present invention provides a kind of cooperative node selection method, comprising:

Obtain the data sending power, source node of source node to the noise power of the available horsepower of the channel gain of destination node, first node, channel, source node to described first node channel gain and destination node to the channel gain of described first node, described first node is a potential cooperative node;

Determine that according to the information that obtains described first node forwards SNR or the signal to noise ratio snr under AF pattern and DF pattern respectively under the DF pattern in the signal to noise ratio snr under amplification forwarding AF pattern or decoding;

If the SNR that described first node is corresponding or the higher value in SNR are the maximum in SNR corresponding to whole potential cooperative nodes, determine that described first node is the cooperative node of this communication;

Determine that according to the information that obtains described first node at the formula of the SNR of AF pattern is:

${\mathrm{\γ}}_{\mathrm{AF}}=P_{S_i}\·G_{S_{i}D}/N_0+\frac{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}{1+(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)};$

Determine respectively that according to the information that obtains described first node at the formula of the SNR of DF pattern is:

${\mathrm{\γ}}_{\mathrm{DF}}=\min \{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0),(P_{S_i}\·G_{S_{i}D}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)\};$

Wherein, Be the transmitted power of described source node,

Be the channel gain of described source node to described destination node, N ₀Be the noise power of channel,

Be the channel gain of described source node to described first node,

Be the available horsepower of described first node,

Be the channel gain of destination node to described first node.

The embodiment of the present invention also provides a kind of cooperative node choice device, comprising:

The first information obtains module, be used for to obtain the data sending power, source node of source node to the available horsepower of the channel gain of destination node, first node, source node to described first node channel gain and destination node to the channel gain of described first node, described first node is a potential cooperative node;

The first signal to noise ratio snr determination module is used for obtaining according to the described first information information that module obtains and determines that described first node forwards SNR or the SNR under AF pattern and DF pattern respectively under the DF pattern in the signal to noise ratio snr under amplification forwarding AF pattern or decoding;

The first processing module is maximum in SNR corresponding to whole potential cooperative nodes if be used for the higher value of SNR corresponding to described first node or SNR, determines that described first node is the cooperative node of this communication;

Determine that according to the information that obtains described first node at the formula of the SNR of AF pattern is:

${\mathrm{\γ}}_{\mathrm{AF}}=P_{S_i}\·G_{S_{i}D}/N_0+\frac{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}{1+(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)};$

Determine respectively that according to the information that obtains described first node at the formula of the SNR of DF pattern is:

${\mathrm{\γ}}_{\mathrm{DF}}=\min \{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0),(P_{S_i}\·G_{S_{i}D}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)\};$

Wherein,

Be the transmitted power of described source node,

Be the channel gain of described source node to described destination node, N ₀Be the noise power of channel,

Be the channel gain of described source node to described first node,

Be the available horsepower of described first node,

Be the channel gain of destination node to described first node.

The embodiment of the present invention also provides a kind of relay station, comprises above-mentioned cooperative node choice device.

The embodiment of the present invention also provides a kind of cooperative node selection method, comprising:

Obtain the data sending power, source node of source node to the noise power of the available horsepower of the channel gain of destination node, each potential cooperative node, channel, source node to described each potential cooperative node channel gain and destination node to the channel gain of described each potential cooperative node;

Determine that according to the information that obtains described each potential cooperative node forwards SNR or the SNR under AF pattern and DF pattern respectively under the DF pattern in the signal to noise ratio snr under amplification forwarding AF pattern or decoding;

Determine that potential cooperative node corresponding to maximum in described SNR is the cooperative node of this communication;

Determine that according to the information that obtains described each potential node at the formula of the SNR of AF pattern is:

${\mathrm{\γ}}_{\mathrm{AF}}=P_{S_i}\·G_{S_{i}D}/N_0+\frac{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}{1+(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)};$

Determine respectively that according to the information that obtains described each potential node at the formula of the SNR of DF pattern is:

${\mathrm{\γ}}_{\mathrm{DF}}=\min \{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0),(P_{S_i}\·G_{S_{i}D}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)\};$

Wherein,

Be the transmitted power of described source node,

Be the channel gain of described source node to described destination node, N ₀Be the noise power of channel,

Be the channel gain of described source node to described each potential node,

Be the available horsepower of described each potential node,

Be the channel gain of destination node to described each potential node.

The embodiment of the present invention also provides a kind of cooperative node choice device, comprising:

The second information acquisition module, be used for to obtain the data sending power, source node of source node to the noise power of the available horsepower of the channel gain of destination node, each potential cooperative node, channel, source node to described each potential cooperative node channel gain and destination node to the channel gain of described each potential cooperative node;

The second signal to noise ratio snr determination module is used for determining that according to the information that described the second information acquisition module obtains described each potential cooperative node forwards SNR or the SNR under AF pattern and DF pattern respectively under the DF pattern in the signal to noise ratio snr under amplification forwarding AF pattern or decoding;

The second processing module is used for determining that potential cooperative node corresponding to maximum of described SNR is the cooperative node of this communication;

Determine that according to the information that obtains described each potential node at the formula of the SNR of AF pattern is:

${\mathrm{\γ}}_{\mathrm{AF}}=P_{S_i}\·G_{S_{i}D}/N_0+\frac{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}{1+(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)};$

Determine respectively that according to the information that obtains described each potential node at the formula of the SNR of DF pattern is:

${\mathrm{\γ}}_{\mathrm{DF}}=\min \{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0),(P_{S_i}\·G_{S_{i}D}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)\};$

Wherein, Be the transmitted power of described source node, Be the channel gain of described source node to described destination node, N ₀Be the noise power of channel,

Be the channel gain of described source node to described each potential node, Be the available horsepower of described each potential node,

Be the channel gain of destination node to described each potential node.

The embodiment of the present invention also provides a kind of base station, comprises above-mentioned cooperative node choice device.

Because the embodiment of the present invention is being carried out cooperative node when selecting, carrying out cooperative node in conjunction with the available resources of potential cooperative node itself selects, considered the available horsepower of potential cooperative node, therefore adopt the technical scheme that the embodiment of the present invention provides can be in the situation that a plurality of potential cooperative nodes are arranged, select a suitable potential cooperative node to communicate, better satisfy effective selection of the cooperative node under multi-user's multi-service parallel transmission, reduce cooperative node because of the not enough situation that can not the effective cooperation transmission of own resource.

Description of drawings

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, the below will do to introduce simply to the accompanying drawing of required use in embodiment or description of the Prior Art, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the system model schematic diagram of a communication system in the embodiment of the present invention;

Fig. 2 is the flow chart of the distributed cooperative node selection method of employing in the embodiment of the present invention;

Fig. 3 is the flow chart of the employing centralized cooperative node selection method in the embodiment of the present invention;

Fig. 4 is the operational flowchart of the first node in embodiment one;

Fig. 5 is the operational flowchart of the first node in embodiment two;

Fig. 6 is the operational flowchart of the first node in embodiment three;

Fig. 7 is the block diagram of the cooperative node choice device in embodiment four;

Fig. 8 is the flow chart of the cooperative node selection method in embodiment five;

Fig. 9 is the block diagram of the cooperative node choice device in embodiment six.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment in the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that obtains under the creative work prerequisite.

Figure 1 shows that the system model of a communication system in the embodiment of the present invention.M mobile terminal S arranged in this system ₁To S _M, N relay station (Relay Station, RS) RS is arranged ₁To RS _NAs potential cooperative node, a common destination node D.Solid line in Fig. 1 shows S ₃Broadcast its data, D and RS ₁, RS ₂RS _NReceive the situation of these data, be shown in dotted line RS ₂Forward the situation of its data that receive as cooperative node.

In embodiments of the present invention, can adopt distributed cooperative node selection scheme, also can adopt centralized cooperative node selection scheme.

Wherein, the distributed cooperative node selection method of the employing in the embodiment of the present invention as shown in Figure 2, the operation of first node comprises the following steps:

Step S101 obtains the channel gain that the data sending power, source node of source node channel gain and the destination node to the noise power of the available horsepower of the channel gain of destination node, first node, channel, source node to first node arrives first node;

This first node is a potential cooperative node.

Step S102, determine that according to the information that obtains first node is at AF(Amplify-and-Forward, amplification forwarding) the SNR(Signal-to-noise ratio under pattern, signal to noise ratio) or DF(Decode-and-Forward, decoding forwards) SNR under pattern or the SNR under AF pattern and DF pattern respectively;

Step S103 if SNR corresponding to first node or the higher value in SNR are the maximum in SNR corresponding to whole potential cooperative nodes, determines that first node is the cooperative node of this communication.

Step S102 has comprised three kinds of situations, is respectively according to the information that obtains to determine that first node is at the SNR under the AF pattern, determine that according to the information that obtains first node is at the SNR under the DF pattern, determine the SNR of first node under AF pattern and DF pattern according to the information that obtains.In the system that only supports the AF pattern, correspondingly be merely able to adopt a kind of in above-mentioned three kinds of situations, namely determine the SNR of first node under the AF pattern according to the information that obtains; In the system that only supports the DF pattern, correspondingly be merely able to adopt a kind of in above-mentioned three kinds of situations, namely determine the SNR of first node under the DF pattern according to the information that obtains; In not only supporting the AF pattern but also support the communication system of DF pattern, can adopt any one in above-mentioned three kinds of situations.In embodiments of the present invention, not only to support the AF pattern but also support the communication system of DF pattern to describe, can only determine the cooperative node of this communication according to the SNR under the AF pattern, also can only determine the cooperative node of this communication according to the SNR under the DF pattern, can also determine the cooperative node that this is communicated by letter according to the greater in the SNR under AF pattern and DF pattern.

Selecting due to cooperative node is a key issue in cooperation communication system.Channel quality between cooperative node and source node and destination node affects the performance of system to a great extent.Existing collaboration mode mainly contains two kinds of AF pattern and DF patterns.In the AF pattern, cooperative node directly amplifies in second stage its information that receives in the phase I that sends; In the DF pattern, cooperative node carries out demodulating and decoding and recompile and sends in second stage the information that its phase I receives.For the DF pattern, the better performances of distance when closer between cooperative node and source node, and for the AF pattern, better performances during near distance between cooperative node and destination node.Therefore, in not only supporting the AF pattern but also support the communication system of DF pattern, employing determines according to the greater in the SNR under AF pattern and DF pattern cooperative node and the forward mode that this is communicated by letter, due to the performance that can consider simultaneously AF pattern and DF pattern, therefore can select better cooperative node and forward mode.and in the system that only supports AF forward mode or DF forward mode, because the embodiment of the present invention is being carried out cooperative node when selecting, carrying out cooperative node in conjunction with the available resources of potential cooperative node itself selects, considered the available horsepower of potential cooperative node, therefore adopt the technical scheme that the embodiment of the present invention provides can be in the situation that a plurality of potential cooperative nodes are arranged, select a suitable potential cooperative node to communicate, better satisfy effective selection of the cooperative node under multi-user's multi-service parallel transmission, reduce cooperative node because of the not enough situation that can not the effective cooperation transmission of own resource.

Employing centralized cooperative node selection method in the embodiment of the present invention comprises the following steps as shown in Figure 3:

Step S201, obtain the data sending power, source node of source node to the noise power of the available horsepower of the channel gain of destination node, each potential cooperative node, channel, source node to described each potential cooperative node channel gain and destination node to the channel gain of described each potential cooperative node;

Step S202 determines that according to the information that obtains described each potential cooperative node is at the SNR under amplification forwarding AF pattern or the SNR under the DF pattern or the SNR under AF pattern and DF pattern respectively;

Step S203 determines that potential cooperative node corresponding to maximum in described SNR is the cooperative node of this communication.

Can find out, because the embodiment of the present invention is being carried out cooperative node when selecting, potential cooperative node has been considered the available horsepower of self, therefore adopt technical scheme that the embodiment of the present invention provides can better satisfy effective selection of the cooperative node under multi-user's multi-service parallel transmission, reduce cooperative node because of the not enough situation that can not the effective cooperation transmission of own resource.

Compare with distributed cooperative node selection scheme, centralized cooperative node selection scheme can reduce the processing complexity of each RS, and distributed cooperative node selection scheme complexity is lower, and signaling consumption is less.In actual applications, can select according to specific needs.

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is described in detail.

Embodiment one

In the present embodiment, adopt distributed cooperative node selection method, be applied in communication system as shown in Figure 1, in the present embodiment, this communication system is only supported the relay transmission of AF pattern.

In the present embodiment, the operating process of first node as shown in Figure 4, and each potential cooperative node carries out respectively corresponding operation to determine self whether cooperation of this communication.As shown in Figure 4, the operating process of first node comprises the following steps:

Step S301 receives source node S _iThe RTS(Request-To-Send of broadcasting, request sends) message, the data sending power of its source node that carries of acquisition from this message

S _iI.e. i mobile terminal, when it initiates a communication process, this S _iIt is source node.

Source node S _iWhen beginning one data transfer, can be to destination node D broadcasting RTS message, the data sending power of having carried source node in this message

Each potential cooperative node also can receive the RTS message of this broadcasting.

Step S302 calculates source node S i to the channel gain of first node according to the RTS message that receives

Step S303 receives the CTS(Clear-To-Send that destination node D broadcasts, and allows to send) message, obtain its source node S of carrying from this message _iChannel gain to destination node D

Destination node D is receiving source node S _iAfter the RTS message of broadcasting, can return to CTS message, carry source node S in this message _iChannel gain to destination node D

Each potential cooperative node also can receive the CTS message of this broadcasting.

Step S304 calculates destination node D to the channel gain of first node according to the CTS message that receives

Step S305 is according to the information of above-mentioned acquisition and the SNR of noise power calculation first node under the AF pattern of channel;

When specific implementation, step S302 not necessarily carried out before step S303 and step S304, as long as execution in step S302 obtains before step S305 calculates

Get final product.

Suppose source node S _iTransmitted power be

First node RS _jGross power be

The current power that has used of expression first node;

The current available horsepower of expression first node.In the embodiment of the present invention, support simultaneously the forwarding of a plurality of Business Streams due to a RS, its power resource can be shared by the mobile terminal of its service, so the first node maximum can be by source node S _iThe power that takies is:

${P^{\′}}_{{\mathrm{RS}}_j}=P_{{\mathrm{RS}}_j}-{\mathrm{\ΔP}}_{{\mathrm{RS}}_j}---\left(1\right)$

Definition ${\mathrm{\γ}}_0=P_{S_i}\·G_{S_{i}D}/N_0,$ ${\mathrm{\γ}}_1=P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0,$ ${\mathrm{\γ}}_2={P^{\′}}_{{\mathrm{RS}}_j}\·G_{{\mathrm{RS}}_{j}D}/N_0,$ Wherein

S _iTo the channel gain of BS,

S _iTo RS _jChannel gain,

RS _jTo the channel gain of D, N ₀Be the noise power of channel, wherein N ₀It can be a set point.

First node is E2E(End to End under the AF pattern, and is end-to-end) SNR as shown in Equation (2):

${\mathrm{\γ}}_{\mathrm{AF}}={\mathrm{\γ}}_0+\frac{{\mathrm{\γ}}_1{\mathrm{\γ}}_2}{1+{\mathrm{\γ}}_1+{\mathrm{\γ}}_2}----\left(2\right)$

γ with above-mentioned definition ₀, γ ₁, γ ₂Bring formula (2) into, can obtain:

${\mathrm{\γ}}_{\mathrm{AF}}=P_{S_i}\·G_{S_{i}D}/N_0+\frac{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}{1+(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}---\left(3\right)$

Step S306, the SNR corresponding according to first node, i.e. γ _AFSet one section duration, the value of this duration and SNR is inversely proportional to;

A timer specifically can be set realize this section setting duration, at this moment, the value of this duration and the SNR value that can be presented as SNR that is inversely proportional to is larger, and timer is faster overtime.

Whether step S307, first node receive the overtime notice of other potential cooperative nodes in this section duration, if, directly finish, otherwise, carry out step S308;

in this step, if first node receives the overtime notice of other potential cooperative nodes in this section duration, the time length that the time length ratio first node SNR corresponding according to it that other potential cooperative nodes SNR corresponding according to it sets sets is described, the value that the SNR that the value of the SNR that other potential cooperative nodes are corresponding according to it is more corresponding according to it than first node namely is described is large, E2E mutual information maximum corresponding to potential cooperative node that this SNR maximum is corresponding, should select potential cooperative node corresponding to this SNR maximum as the cooperative node of this communication, so, first node is not selected, directly finish.

If this section set duration and realized by timer, so, in this step, if first node receives the overtime notice of other potential cooperative nodes in this section duration, the timer setting duration that it is corresponding is infinite, its corresponding timer is overtime never, and first node in this communication process, just can not carry out because timer triggers subsequent operation.

Step S308 determines that after this duration first node is the cooperative node of this communication, and notifies the setting duration of other potential cooperative node first nodes overtime.

After definite first node is the cooperative node of this communication, adopt the AF pattern to carry out relay transmission.

If first node does not receive the overtime notice of other potential cooperative nodes in this section duration, can determine that SNR corresponding to first node is the maximum in SNR corresponding to whole potential cooperative nodes, can notify the setting duration of other potential cooperative node first nodes overtime after this duration.Other potential cooperative nodes are after receiving the overtime notice of first node, and the SNR that determines self is not the maximum in SNR corresponding to whole potential cooperative nodes.

can find out, due in the present embodiment, considered the available horsepower of potential cooperative node when calculating SNR, available horsepower and source node and cooperative node with potential cooperative node, the channel quality of source node and destination node and cooperative node and destination node combines, but there is no the potential cooperative node of available horsepower as the situation of cooperative node although so just avoided selecting certain to have optimum channel quality, therefore adopt technical scheme that the present embodiment provides can better satisfy effective selection of the cooperative node under multi-user's multi-service parallel transmission, reduce cooperative node because of the not enough situation that can not the effective cooperation transmission of own resource.

When specific implementation, not only supporting the AF pattern but also supporting also can to use the technical scheme that the present embodiment provides in the communication system of DF pattern, but when the technical scheme that application the present embodiment provides, the potential cooperative node of each in this communication system also can only be determined cooperative node according to the SNR under the AF pattern.

Embodiment two

In the present embodiment, adopt distributed cooperative node selection method, be applied in communication system as shown in Figure 1, in the present embodiment, this communication system is only supported the relay transmission of DF pattern.

In the present embodiment, the operating process of first node as shown in Figure 5, and each potential cooperative node carries out respectively corresponding operation to determine self whether cooperation of this communication.As shown in Figure 5, the operating process of first node comprises the following steps:

Step S401 receives source node S _iThe RTS message of broadcasting, the data sending power of its source node that carries of acquisition from this message

S _iI.e. i mobile terminal, when it initiates a communication process, this S _iIt is source node.

Source node S _iWhen beginning one data transfer, can be to destination node D broadcasting RTS message, the data sending power of having carried source node in this message

Each potential cooperative node also can receive the RTS message of this broadcasting.

Step S402 calculates source node S i to the channel gain of first node according to the RTS message that receives

Step S403 receives the CTS message that destination node D broadcasts, and obtains its source node S of carrying from this message _iChannel gain to destination node D

Destination node D is receiving source node S _iAfter the RTS message of broadcasting, can return to CTS message, carry source node S in this message _iChannel gain to destination node D

Each potential cooperative node also can receive the CTS message of this broadcasting.

Step S404 calculates destination node D to the channel gain of first node according to the CTS message that receives

Step S405 is according to the information of above-mentioned acquisition and the SNR of noise power calculation first node under the DF pattern of channel;

When specific implementation, step S402 not necessarily carried out before step S403 and step S404, as long as execution in step S402 obtains before step S405 calculates

Get final product.

First node is E2E(End to End under the DF pattern, and is end-to-end) SNR as shown in Equation (4):

γ _DF=min{γ ₁,γ ₀+γ ₂} (4)

That is, γ _DFBe γ ₀And γ ₁+ γ ₂In the smaller.

Definition ${\mathrm{\γ}}_0=P_{S_i}\·G_{S_{i}D}/N_0,$ ${\mathrm{\γ}}_1=P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0,$ ${\mathrm{\γ}}_2={P^{\′}}_{{\mathrm{RS}}_j}\·G_{{\mathrm{RS}}_{j}D}/N_0,$ And with γ ₀, γ ₁, γ ₂Bring formula (4) into, can obtain:

${\mathrm{\γ}}_{\mathrm{DF}}=\min \{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0),(P_{S_i}\·G_{S_{i}D}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)\}---\left(5\right)$

Wherein S _iTo the channel gain of BS,

S _iTo RS _jChannel gain,

RS _jTo the channel gain of D, N ₀Be the noise power of channel, wherein N ₀It can be a set point.

Step S406, the SNR corresponding according to first node, i.e. γ _DFSet one section duration, the value of this duration and SNR is inversely proportional to;

Whether step S407, first node receive the overtime notice of other potential cooperative nodes in this section duration, if, directly finish, otherwise, carry out step S408;

In this step, if first node receives the overtime notice of other potential cooperative nodes in this section duration, the value of determining the SNR that first node is corresponding is not the maximum in SNR corresponding to whole potential cooperative nodes.

Step S408 determines that after this duration first node is the cooperative node of this communication, and notifies the setting duration of other potential cooperative node first nodes overtime.

After definite first node is the cooperative node of this communication, adopt the DF pattern to carry out relay transmission.

If first node does not receive the overtime notice of other potential cooperative nodes in this section duration, can determine that SNR corresponding to first node is the maximum in SNR corresponding to whole potential cooperative nodes.

can find out, due in the present embodiment, considered the available horsepower of potential cooperative node when calculating SNR, available horsepower and source node and cooperative node with potential cooperative node, the channel quality of source node and destination node and cooperative node and destination node combines, but there is no the potential cooperative node of available horsepower as the situation of cooperative node although so just avoided selecting certain to have optimum channel quality, therefore adopt technical scheme that the present embodiment provides can better satisfy effective selection of the cooperative node under multi-user's multi-service parallel transmission, reduce cooperative node because of the not enough situation that can not the effective cooperation transmission of own resource.

When specific implementation, not only supporting the AF pattern but also supporting also can to use the technical scheme that the present embodiment provides in the communication system of DF pattern.

Embodiment three

In the present embodiment, adopt distributed cooperative node selection method, be applied in communication system as shown in Figure 1, in the present embodiment, this communication system had not only been supported the AF pattern but also had been supported the relay transmission of DF pattern.

In the present embodiment, the operating process of first node as shown in Figure 6, and each potential cooperative node carries out respectively corresponding operation to determine self whether cooperation of this communication.As shown in Figure 6, the operating process of first node comprises the following steps:

Step S501 receives source node S _iThe RTS message of broadcasting, the data sending power of its source node that carries of acquisition from this message

S _iI.e. i mobile terminal, when it initiates a communication process, this S _iIt is source node.

Source node S _iWhen beginning one data transfer, can be to destination node D broadcasting RTS message, the data sending power of having carried source node in this message

Each potential cooperative node also can receive the RTS message of this broadcasting.

Step S502 calculates source node S i to the channel gain of first node according to the RTS message that receives

Step S503 receives the CTS message that destination node D broadcasts, and obtains its source node S of carrying from this message _iChannel gain to destination node D

Destination node D is receiving source node S _iAfter the RTS message of broadcasting, can return to CTS message, carry source node S in this message _iChannel gain to destination node D

Each potential cooperative node also can receive the CTS message of this broadcasting.

Step S504 calculates destination node D to the channel gain of first node according to the CTS message that receives

Step S505 calculates the SNR of first node under the AF pattern according to the information of above-mentioned acquisition and the noise power of channel by formula (3);

Step S506 calculates the SNR of first node under the DF pattern according to the information of above-mentioned acquisition and the noise power of channel by formula (5);

When specific implementation, step S502 not necessarily carried out before step S503 and step S504, as long as execution in step S502 obtains before calculating SNR

Get final product.And step S505 and step S506 piece with certain sequencing.

Step S507, the SNR corresponding according to first node, i.e. γ _AFAnd γ _DFIn the greater set one section duration, the value of this duration and SNR is inversely proportional to;

Whether step S508, first node receive the overtime notice of other potential cooperative nodes in this section duration, if, directly finish, otherwise, carry out step S509;

In this step, if first node receives the overtime notice of other potential cooperative nodes in this section duration, the value of determining the SNR that first node is corresponding is not the maximum in SNR corresponding to whole potential cooperative nodes.

Step S509 determines that after this duration first node is the cooperative node of this communication, determines γ _AFAnd γ _DFIn forward mode corresponding to the greater (being the maximum in SNR corresponding to whole potential cooperative nodes) be described first node to the forward mode of this communication, and notify the setting duration of other potential cooperative node first nodes overtime.

In this step directly according to γ _AFAnd γ _DFIn the greater determine that the forward mode of first node is a preferred embodiment, when specific implementation, in this step only definite first node for the cooperative node of this communication and notify the setting duration of other potential cooperative node first nodes overtime, and first node specifically adopts any mode to determine that forward mode can be selected according to other strategies, is not construed as limiting here.

If first node does not receive the overtime notice of other potential cooperative nodes in this section duration, can determine that SNR corresponding to first node is the maximum in SNR corresponding to whole potential cooperative nodes.

Can find out, in the present embodiment, consider simultaneously the SNR of AF pattern and DF pattern, select maximum SNR from these two kinds of patterns, with cooperative node and the transmission mode of acquisition E2E mutual information maximum, thereby carry out better the selection of cooperative node.and, due in the present embodiment, considered the available horsepower of potential cooperative node when calculating SNR, available horsepower and source node and cooperative node with potential cooperative node, the channel quality of source node and destination node and cooperative node and destination node combines, but there is no the potential cooperative node of available horsepower as the situation of cooperative node although so just avoided selecting certain to have optimum channel quality, therefore adopt technical scheme that the present embodiment provides can better satisfy effective selection of the cooperative node under multi-user's multi-service parallel transmission, reduce cooperative node because of the not enough situation that can not the effective cooperation transmission of own resource.

Embodiment four

Cooperative node choice device in the present embodiment as shown in Figure 7, comprising:

The first information obtains module 11, be used for to obtain the data sending power, source node of source node to the available horsepower of the channel gain of destination node, first node, source node to described first node channel gain and destination node to the channel gain of described first node, described first node is a potential cooperative node;

The one SNR determination module 12 is used for obtaining according to the first information information that module 11 obtains and determines that described first node is at the SNR under amplification forwarding AF pattern or the SNR under the DF pattern or the SNR under AF pattern and DF pattern respectively;

The first processing module 13 is maximum in SNR corresponding to whole potential cooperative nodes if be used for the higher value of SNR corresponding to described first node or SNR, determines that described first node is the cooperative node of this communication.

Further, the device in the present embodiment can also comprise the first forward mode determination module, is used for determining that forward mode corresponding to described maximum is the forward mode of this communication.

Be used for determining described first node in the situation that the SNR under AF pattern and DF pattern according to the information that obtains at a SNR determination module 12, can comprise timer, Timer Controlling unit, cooperative node determining unit in the first processing module, wherein:

The Timer Controlling unit, the higher value that is used for the SNR corresponding according to described first node arranges the duration of described timer, the duration of the higher value setting in the described SNR corresponding according to described first node and the value of SNR are inversely proportional to, and the duration of described timer is set to infinite after receiving the overtime notice of other potential cooperative nodes;

The cooperative node determining unit, be used for after described timer expiry, determine that higher value in SNR corresponding to described first node is the maximum in SNR corresponding to whole potential cooperative nodes, and notify the timer expiry of the described first node of other potential cooperative nodes.

Cooperative node choice device in the present embodiment can be included in relay station, can be also independent device, communicates with relay station.

Embodiment five

In the present embodiment, adopt the centralized cooperative node selection method, be applied in communication system as shown in Figure 1.

In the present embodiment, cooperative node selection method comprises the following steps as shown in Figure 8:

Step S601, obtain the data sending power, source node of source node to the noise power of the available horsepower of the channel gain of destination node, each potential cooperative node, channel, source node to described each potential cooperative node channel gain and destination node to the channel gain of described each potential cooperative node;

The acquisition pattern of above-mentioned information can be referring to embodiment one.

Step S602, according to the information that obtains, calculate each potential cooperative node by formula (3) and calculate each potential cooperative node at the SNR under the DF pattern or calculate each potential cooperative node by formula (3) and calculate the SNR of each potential cooperative node under the DF pattern at the SNR under the AF pattern and by formula (5) at the SNR under the AF pattern or by formula (5);

Step S603 determines that potential cooperative node corresponding to maximum in above-mentioned SNR is the cooperative node of this communication.

After determining cooperative node, it is confirmed as the cooperative node of this communication can to send out this RS of message informing, and this RS can forward corresponding data according to this notice.

To determine described first node in the situation that the SNR under AF pattern and DF pattern can also determine that forward mode corresponding to maximum in described SNR is the forward mode of this communication according to the information that obtains in step S602.

Compare with distributed cooperative node selection scheme, centralized cooperative node selection scheme can reduce the processing complexity of each RS, compare with centralized cooperative node selection scheme, distributed cooperative node selection scheme complexity is lower, and signaling consumption is less.In actual applications, can select according to specific needs.

Embodiment six

Cooperative node choice device in the present embodiment as shown in Figure 9, comprising:

The second information acquisition module 21, be used for to obtain the data sending power, source node of source node to the noise power of the available horsepower of the channel gain of destination node, each potential cooperative node, channel, source node to described each potential cooperative node channel gain and destination node to the channel gain of described each potential cooperative node;

The 2nd SNR determination module 22 is used for determining that according to the information that the second information acquisition module 21 obtains each potential cooperative node is at the signal to noise ratio snr under amplification forwarding AF pattern or the SNR under the DF pattern or the SNR under AF pattern and DF pattern respectively;

The second processing module 23, potential cooperative node corresponding to maximum that is used for the SNR of definite the 2nd SNR determination module 22 acquisitions is the cooperative node of this communication.

Device in the present embodiment can also comprise the second forward mode determination module, is used for determining that forward mode corresponding to maximum of described SNR is the forward mode of this communication.

Cooperative node choice device in the present embodiment can be included in the base station, can be also independent device.

Obviously, those skilled in the art can carry out various changes and modification and not break away from the spirit and scope of the present invention the present invention.Like this, if within of the present invention these are revised and modification belongs to the scope of claim of the present invention and equivalent technologies thereof, the present invention also is intended to comprise these changes and modification interior.

Claims (12)

1. a cooperative node selection method, is characterized in that, comprising:

Obtain the data sending power, source node of source node to the noise power of the available horsepower of the channel gain of destination node, first node, channel, source node to described first node channel gain and destination node to the channel gain of described first node, described first node is a potential cooperative node;

Determine that according to the information that obtains described first node forwards SNR or the SNR under AF pattern and DF pattern respectively under the DF pattern in the signal to noise ratio snr under amplification forwarding AF pattern or decoding;

If the SNR that described first node is corresponding or the higher value in SNR are the maximum in SNR corresponding to whole potential cooperative nodes, determine that described first node is the cooperative node of this communication;

Determine that according to the information that obtains described first node at the formula of the SNR of AF pattern is:

${\mathrm{\γ}}_{\mathrm{AF}}=P_{S_i}\·G_{S_i/D}/N_0+\frac{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}{1+(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)};$

Determine respectively that according to the information that obtains described first node at the formula of the SNR of DF pattern is:

${\mathrm{\γ}}_{\mathrm{DF}}=\min \{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0),(P_{S_i}\·G_{S_{i}D}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)\};$

Wherein, Be the transmitted power of described source node,

Be the channel gain of described source node to described destination node, N ₀Be the noise power of channel,

Be the channel gain of described source node to described first node,

Be the available horsepower of described first node,

Be the channel gain of destination node to described first node.

2. method according to claim 1, it is characterized in that, if the SNR that described first node is corresponding or the higher value in SNR are the maximum in SNR corresponding to whole potential cooperative nodes, also comprise step: the forward mode that described maximum is corresponding is defined as the forward mode of this communication.

3. method according to claim 1, is characterized in that, determining that according to the information that obtains described first node after the SNR under AF pattern and DF pattern, also comprises:

Higher value in the SNR corresponding according to described first node is set one section duration, and the value of described duration and SNR is inversely proportional to;

If described first node does not receive the overtime notice of other potential cooperative nodes in described duration, higher value in the SNR that definite described first node is corresponding is the maximum in SNR corresponding to whole potential cooperative nodes, and notifies the setting duration of the described first node of other potential cooperative nodes overtime after this duration.

4. a cooperative node choice device, is characterized in that, comprising:

The first information obtains module, be used for to obtain the data sending power, source node of source node to the available horsepower of the channel gain of destination node, first node, source node to described first node channel gain and destination node to the channel gain of described first node, described first node is a potential cooperative node;

The first signal to noise ratio snr determination module is used for obtaining according to the described first information information that module obtains and determines that described first node forwards SNR or the SNR under AF pattern and DF pattern respectively under the DF pattern in the signal to noise ratio snr under amplification forwarding AF pattern or decoding;

The first processing module is maximum in SNR corresponding to whole potential cooperative nodes if be used for the higher value of SNR corresponding to described first node or SNR, determines that described first node is the cooperative node of this communication;

Determine that according to the information that obtains described first node at the formula of the SNR of AF pattern is:

${\mathrm{\γ}}_{\mathrm{AF}}=P_{S_i}\·G_{S_i/D}/N_0+\frac{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}{1+(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)};$

Determine respectively that according to the information that obtains described first node at the formula of the SNR of DF pattern is:

${\mathrm{\γ}}_{\mathrm{DF}}=\min \{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0),(P_{S_i}\·G_{S_{i}D}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)\};$

Wherein, Be the transmitted power of described source node,

Be the channel gain of described source node to described destination node, N ₀Be the noise power of channel,

Be the channel gain of described source node to described first node,

Be the available horsepower of described first node,

Be the channel gain of destination node to described first node.

5. device according to claim 4, is characterized in that,

Described device also comprises the first forward mode determination module, is used for determining that forward mode corresponding to described maximum is the forward mode of this communication.

6. device according to claim 4, it is characterized in that, when being used for obtaining according to the described first information information that module obtains, a described SNR determination module determines that described first node is respectively during the SNR under AF pattern and DF pattern, described the first processing module comprises timer, Timer Controlling unit, cooperative node determining unit, wherein:

Described Timer Controlling unit, the higher value that is used for the SNR corresponding according to described first node arranges the duration of described timer, the value of described duration and SNR is inversely proportional to, and the duration of described timer is set to infinite after receiving the overtime notice of other potential cooperative nodes;

Described cooperative node determining unit, be used for after described timer expiry, determine that higher value in SNR corresponding to described first node is the maximum in SNR corresponding to whole potential cooperative nodes, and notify the timer expiry of the described first node of other potential cooperative nodes.

7. a relay station, is characterized in that, comprises the described cooperative node choice device of claim as arbitrary in claim 4 to 6.

8. a cooperative node selection method, is characterized in that, comprising:

Obtain the data sending power, source node of source node to the noise power of the available horsepower of the channel gain of destination node, each potential cooperative node, channel, source node to described each potential cooperative node channel gain and destination node to the channel gain of described each potential cooperative node;

Determine that according to the information that obtains described each potential cooperative node forwards SNR or the signal to noise ratio snr under AF pattern and DF pattern respectively under the DF pattern in the signal to noise ratio snr under amplification forwarding AF pattern or decoding;

Determine that potential cooperative node corresponding to maximum in described SNR is the cooperative node of this communication;

Determine that according to the information that obtains described each potential node at the formula of the SNR of AF pattern is:

${\mathrm{\γ}}_{\mathrm{AF}}=P_{S_i}\·G_{S_i/D}/N_0+\frac{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}{1+(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)};$

Determine respectively that according to the information that obtains described each potential node at the formula of the SNR of DF pattern is:

${\mathrm{\γ}}_{\mathrm{DF}}=\min \{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0),(P_{S_i}\·G_{S_{i}D}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)\};$

Wherein,

Be the transmitted power of described source node,

Be the channel gain of described source node to described destination node, N ₀Be the noise power of channel,

Be the channel gain of described source node to described each potential node,

Be the available horsepower of described each potential node,

Be the channel gain of destination node to described each potential node.

9. method according to claim 8, is characterized in that, also comprises:

Determine that forward mode corresponding to maximum in described SNR is the forward mode of this communication.

10. a cooperative node choice device, is characterized in that, comprising:

The second information acquisition module, be used for to obtain the data sending power, source node of source node to the noise power of the available horsepower of the channel gain of destination node, each potential cooperative node, channel, source node to described each potential cooperative node channel gain and destination node to the channel gain of described each potential cooperative node;

The second signal to noise ratio snr determination module is used for determining that according to the information that described the second information acquisition module obtains described each potential cooperative node forwards SNR or the SNR under AF pattern and DF pattern respectively under the DF pattern in the signal to noise ratio snr under amplification forwarding AF pattern or decoding;

The second processing module is used for determining that potential cooperative node corresponding to maximum of described SNR is the cooperative node of this communication;

Determine that according to the information that obtains described each potential node at the formula of the SNR of AF pattern is:

${\mathrm{\γ}}_{\mathrm{AF}}=P_{S_i}\·G_{S_i/D}/N_0+\frac{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)}{1+(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)};$

Determine respectively that according to the information that obtains described each potential node at the formula of the SNR of DF pattern is:

${\mathrm{\γ}}_{\mathrm{DF}}=\min \{(P_{S_i}\·G_{S_i{\mathrm{RS}}_j}/N_0),(P_{S_i}\·G_{S_{i}D}/N_0)+({P^{\′}}_{{\mathrm{RS}}_i}\·G_{{\mathrm{RS}}_{i}D}/N_0)\};$

Wherein,

Be the transmitted power of described source node, Be the channel gain of described source node to described destination node, N ₀Be the noise power of channel, Be the channel gain of described source node to described each potential node,

Be the available horsepower of described each potential node,

Be the channel gain of destination node to described each potential node.

11. device according to claim 10 is characterized in that, described device also comprises the second forward mode determination module, is used for determining that forward mode corresponding to maximum of described SNR is the forward mode of this communication.

12. a base station is characterized in that, comprises the described cooperative node choice device of claim 10 or 11.

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