CN102098681B - Cooperative data transmission method and system for adaptive relay selection - Google Patents

Cooperative data transmission method and system for adaptive relay selection Download PDF

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CN102098681B
CN102098681B CN 201010585038 CN201010585038A CN102098681B CN 102098681 B CN102098681 B CN 102098681B CN 201010585038 CN201010585038 CN 201010585038 CN 201010585038 A CN201010585038 A CN 201010585038A CN 102098681 B CN102098681 B CN 102098681B
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grouping
terminal
transmission rate
cooperation
competition
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CN102098681A (en
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刘凯
张玉鹏
李亚燕
刘锋
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Beihang University
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Beihang University
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Abstract

The invention provides a cooperative data transmission method and a cooperative data transmission system for adaptive relay selection. The method comprises the following steps of: calculating withdrawal time according to a first transmission speed from a source terminal to an adjacent terminal, a second transmission speed from an adjacent terminal to a target terminal and a third transmission speed from the source terminal to the target terminal, which are acquired; if ready-to-help packets transmitted by other adjacent terminals are not intercepted, transmitting the ready-to-help packets to the source terminal and the target terminal respectively according to the withdrawal time, wherein every ready-to-help packet comprises the first transmission speed and the second transmission speed; receiving a cooperative clear to send (CCTS) packet replied by the target terminal; and receiving a data packet transmitted by the source terminal, and forwarding the data packet to the target terminal at the second transmission speed. So, the problem that candidate relay terminals compete and collide in the prior art is solved, a competition time delay is effectively shortened, and the throughput of data transmission is effectively improved.

Description

Collaboration data transmission method and the system of self adaptation relay selection
Technical field
The embodiment of the invention relates to the communication technology, relates in particular to a kind of collaboration data transmission method and system of self adaptation relay selection.
Background technology
Wireless communication technology is with fastest developing speed, the most widely used communication technology in the communications field in the last few years.In radio communication, because channel fading and path loss, the signal quality that receives can be than the bigger decline that has in the wire message way.For this reason, various anti-interference, antimierophonic wireless communication technologys have been proposed at present.Multiple-input and multiple-output (Multiple-Input Multiple-Output; Be called for short MIMO) be exactly a kind of method of utilizing space diversity greatly to improve signal quality wherein.The collaboration communication technology has been used the thought of MIMO, forms virtual antenna array to reach the effect of MIMO diversity by the antenna that is distributed on the different nodes.Compare with non-cooperative system, adopt collaboration communication can obtain obvious performance gain.In wireless network, medium access control (Medium Access Control; Be called for short: MAC) method or access transmission method have solved each mobile subscriber or how fair node is, insert quickly and safely and use channel, share the problem of limited wireless bandwidth resources efficiently.The quality of MAC method directly has influence on the quality of performance index such as network throughput, time delay.The advantage of utilizing collaboration diversity to provide in physical layer adopts the MAC method of cooperation can more reasonably arrange user's shared channel, improves network performance.
At present, this MAC method mainly comprises cooperation formula MAC (Cooperative MAC; Be called for short: CoopMAC) method, its concrete implementation is: each terminal is safeguarded a cooperation table (Cooptable), be used for record candidate relay terminal information, in each transfer of data, select optimum terminal as link terminal in the candidate relay terminal information that source terminal records from cooperation table, and send cooperation transmission request (Cooperative Request to Send by source terminal; Be called for short: CRTS) grouping, link terminal is replied cooperating relay (Helper-to-Send; Be called for short: HTS) grouping, purpose terminal are replied the cooperation transmission and are confirmed (Cooperative Clear to Send; Be called for short: CCTS) grouping three-way handshake mechanism, thereby make source terminal with two-forty to this link terminal transport service group, link terminal is transmitted traffic packets with two-forty to the purpose terminal again.In addition, after each transfer of data was finished, each terminal was upgraded cooperation table according to the channel information that listens to.But in the CoopMAC method, each terminal will be safeguarded a cooperation table, thereby increased storage overhead, in addition, because terminal moves and the time variation of channel, therefore, the cooperation table of its storage can not be followed the in good shape adaptation of instantaneous network, thus the dynamic change of incompatibility network.
In order to adapt to the situation of network dynamic change, this MAC method mainly can also comprise the self-adjusting cooperation formula of relaying speed (Cooperative Relay-Based Auto Rate; Be called for short: CRBAR) method, in the CRBAR method, all candidate relay terminals are obtained it to the Real-time Channel state status of source terminal and purpose terminal from CRTS, the CCTS grouping that listens to, and calculate it to the speed of source terminal and purpose terminal, satisfying under the cooperation condition, the candidate relay terminal begins competition.But, in the CRBAR method, each candidate relay terminal begins to go to be at war with certain probability at each mini-slot, though the terminal of different rates grade has different competition probability, but under the more situation of via node number, can there be unnecessary conflict in this method and the problem of the failure that causes cooperating.
Summary of the invention
The embodiment of the invention provides a kind of collaboration data transmission method and system of self adaptation relay selection, the candidate relay terminal challenge produces the problem of collision in the prior art in order to have solved, thereby shortened the competition time delay effectively, and improved the throughput of transfer of data effectively.
The embodiment of the invention provides a kind of collaboration data transmission method of self adaptation relay selection, comprising:
If the source terminal that gets access to is to the first transmission rate R of adjacent terminal SR, described adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of described source terminal to described purpose terminal SDSatisfy formula
Figure BSA00000383045400031
Then according to formula
Figure BSA00000383045400032
Calculate back off time T AW
Do not send preparation cooperation grouping if listen to other adjacent terminals, then according to described back off time T AW, to send for respectively described source terminal and purpose terminal and prepare the cooperation grouping, described preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RD
Receive the answer cooperation transmission affirmation grouping that described purpose terminal is replied;
Receive the packet that described source terminal sends, and transmit described packet with second transmission rate and give described purpose terminal;
Wherein, λ is a predefined constant; N CAInsert the number of times of grouping for the competition that receives described purpose terminal transmission; T CWBe the competition window time.
The embodiment of the invention provides a kind of collaboration data transmission system of self adaptation relay selection, comprises source terminal, purpose terminal and adjacent terminal, and wherein, described adjacent terminal comprises:
The back off time computing module is used for if the source terminal that gets access to arrives the first transmission rate R of adjacent terminal SR, described adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of described source terminal to described purpose terminal SDSatisfy formula
Figure BSA00000383045400033
Then according to formula
Figure BSA00000383045400034
Calculate back off time T AW
The first preparation cooperation grouping sending module is used for preparing the cooperation grouping if listen to other adjacent terminals transmissions, then according to described back off time T AW, to send for respectively described source terminal and purpose terminal and prepare the cooperation grouping, described preparation cooperation grouping comprises the described first transmission rate R SDWith the second transmission rate R RD
Cooperation sends confirms the receiver module that divides into groups, for receiving the answer cooperation transmission affirmation grouping that described purpose terminal is replied;
Forwarding module is used for receiving the packet that described source terminal sends, and transmits described packet with second transmission rate and give described purpose terminal;
Wherein, λ is a predefined constant; N CAInsert the number of times of grouping for the competition that receives described purpose terminal transmission; T CWBe the competition window time.
Collaboration data transmission method and the system of the self adaptation relay selection of the embodiment of the invention are by arriving the first transmission rate R of adjacent terminal at source terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula
Figure BSA00000383045400041
Then according to formula
Figure BSA00000383045400042
Calculate back off time T AWIf do not listen to the preparation cooperation grouping that other adjacent terminals send, then according to back off time T AW, sending and prepare the cooperation grouping, this preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RDThe answer cooperation of replying according to the purpose terminal that receives at last sends and confirms grouping, transmit the packet of source terminal transmission to the purpose terminal, the candidate relay terminal challenge produces the problem of collision in the prior art thereby solved, and then shortened the competition time delay effectively, and improved the throughput of transfer of data effectively.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, to do one to the accompanying drawing of required use in embodiment or the description of the Prior Art below introduces simply, apparently, accompanying drawing in describing below is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the flow chart of an embodiment of the collaboration data transmission method of self adaptation relay selection of the present invention;
Fig. 2 is the flow chart of another embodiment of the collaboration data transmission method of self adaptation relay selection of the present invention;
Fig. 3 is the flow chart of another embodiment of the collaboration data transmission method of self adaptation relay selection of the present invention;
Fig. 4 is at a distance of the network topology structure schematic diagram of double bounce between the link terminal;
Fig. 5 is the structural representation of an embodiment of the collaboration data transmission system of self adaptation relay selection of the present invention;
Fig. 6 is the structural representation of another embodiment of the collaboration data transmission system of self adaptation relay selection of the present invention;
Fig. 7 is the structural representation of another embodiment of the collaboration data transmission system of self adaptation relay selection of the present invention;
Fig. 8 is the also structural representation of an embodiment of the collaboration data transmission system of self adaptation relay selection of the present invention.
Embodiment
For the purpose, technical scheme and the advantage that make the embodiment of the invention clearer, below in conjunction with the accompanying drawing in the embodiment of the invention, technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among 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.
Fig. 1 is the flow chart of an embodiment of the collaboration data transmission method of self adaptation relay selection of the present invention, as shown in Figure 1, the executive agent of present embodiment is adjacent terminal, also can be referred to as candidate's link terminal, and should neighbour's terminal and other adjacent terminals jump at a distance of one, this method comprises:
Step 101, if the source terminal that gets access to the first transmission rate R of adjacent terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula:
R SR ≥ 2 R SD R RD ≥ 2 R SD - - - ( 1 )
Then according to formula (2):
T AW = λ 1 R SD - ( 1 R SR + 1 R RD ) - T CW * N CA - - - ( 2 )
Calculate back off time T AW
Wherein, λ is a predefined constant; N CAFor receiving competition access (the Contention Access that the purpose terminal sends; Be called for short: CA) Fen Zu number of times; T CWBe the competition window time.
In the present embodiment, before source terminal sent packet, if source terminal was at distributed frame interval (Distributions Inter Frame Spacing; Be called for short: DIFS) after time, when listening to channel idle, then send the CRTS grouping to the purpose terminal.The purpose terminal is decoded to this CRTS after receiving the CRTS grouping, to judge whether correctly to receive this CRTS grouping, if correctly receive this CRTS grouping, and in DIFS, when listening to channel idle, replys RTR and divides into groups to source terminal.This RTR grouping comprises the 3rd transmission rate R between source terminal and the purpose terminal SD, need to prove the 3rd transmission rate R SDBe supported maximum transmission rate between source terminal and the purpose terminal.
In addition, adjacent terminal can listen to this CRTS grouping and RTR grouping, and the signal to noise ratio that can obtain according to this CRTS grouping, calculates the first transmission rate R that source terminal arrives adjacent terminal SR, and according to the signal to noise ratio that this RTR grouping is obtained, calculate adjacent terminal to the second transmission rate R between the purpose terminal RD, and according to decoding RTR grouping, draw the 3rd transmission rate R SDWherein, the first transmission rate R SRBe supported maximum transmission rate between source terminal and the adjacent terminal; The second transmission rate R RDBe supported maximum transmission rate between adjacent terminal and the purpose terminal.
In the present embodiment, all adjacent terminals adjacent with the purpose terminal with source terminal can listen to CRTS grouping and RTR grouping, and can calculate the first transmission rate R respectively according to the signal to noise ratio in this CRTS grouping and the RTR grouping SRWith the second transmission rate R RD, and RTR grouping decoded, draw the 3rd transmission rate R SD, if this first transmission rate R SR, the second transmission rate R RDWith the 3rd transmission rate R SDSatisfy formula (1), illustrate that then this neighbour's terminal can be used as link terminal, transmission of data packets between source terminal and the purpose terminal namely can cooperate.
In addition, can also calculate back off time T according to formula (2) as the adjacent terminal of link terminal AW, with at this back off time T AWAfter, prepare cooperation (Ready-To-Help with the form transmission of broadcasting; Be called for short: RTH) grouping, thus make purpose terminal and source terminal all can receive this RTH grouping.It should be noted that in the present embodiment N CA=1.
Step 102, send RTH grouping if intercept other adjacent terminals, then according to back off time T AW, sending the RTH grouping, this RTH grouping comprises the first transmission rate R SRWith the second transmission rate R RD
In the present embodiment, the form transmission RTH grouping of adjacent terminal to broadcast as link terminal all can receive this RTH grouping to guarantee source terminal and purpose terminal.
The CCTS grouping that step 103, reception purpose terminal are replied.
In the present embodiment, at T CWIn, if the purpose terminal correctly receives the RTH grouping, and do not listen to when colliding generation, then reply CCTS and divide into groups to this link terminal, to announce beginning packet transmission.
The packet that step 104, reception sources terminal send, and transmit this packet with second transmission rate and give the purpose terminal.
In the present embodiment, after source terminal receives that correctly the CCTS of purpose terminal transmission divides into groups, then with the first transmission rate R SRSend packet to this link terminal, this link terminal is again with the second transmission rate R RDTransmit packet and give the purpose terminal.After the purpose terminal correctly receives packet, reply and confirm (Acknowledge; Be called for short: ACK) link terminal is given in grouping, by link terminal the ACK grouping is transmitted to source terminal again.
In the present embodiment, by arrive the first transmission rate R of adjacent terminal at source terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula
Figure BSA00000383045400071
Then according to formula
Figure BSA00000383045400072
Calculate back off time T AWIf do not listen to the preparation cooperation grouping that other adjacent terminals send, then according to back off time T AW, sending and prepare the cooperation grouping, this preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RDThe answer cooperation of replying according to the purpose terminal that receives at last sends and confirms grouping, transmit the packet of source terminal transmission to the purpose terminal, the candidate relay terminal challenge produces the problem of collision in the prior art thereby solved, and then shortened the competition time delay effectively, and improved the throughput of transfer of data effectively.
Fig. 2 is the flow chart of another embodiment of the collaboration data transmission method of self adaptation relay selection of the present invention, and as shown in Figure 2, the executive agent of present embodiment is adjacent terminal, and should neighbour's terminal and the jumping apart of other adjacent terminals.In addition, this neighbour's terminal can also be referred to as candidate's link terminal, and then this method comprises:
Step 201, if the source terminal that gets access to the first transmission rate R of adjacent terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula:
R SR ≥ 2 R SD R RD ≥ 2 R SD - - - ( 1 )
Then according to formula (2):
T AW = λ 1 R SD - ( 1 R SR + 1 R RD ) - T CW * N CA - - - ( 2 )
Calculate back off time T AW
Wherein, λ is a predefined constant; N CAInsert the number of times of CA grouping for the competition that receives the transmission of purpose terminal; T CWBe the competition window time.
In the present embodiment, the implementation of step 201 and the implementation of step 101 shown in Figure 1 are similar, repeat no more herein.
Step 202, whether listen to other adjacent terminals and send RTH grouping, if not, then execution in step 203; If then finish.
In the present embodiment, when the relaying terminal listens to other adjacent terminals when sending RTH grouping, then withdraw from this cooperation transmission.
Step 203, according to back off time T AW, sending the RTH grouping, this RTH grouping comprises the first transmission rate R SRWith the second transmission rate R RD
In the present embodiment, can there be a plurality of adjacent terminals to satisfy formula (1), as link terminal.Each link terminal can calculate back off time T according to formula (2) AW, and at back off time T AWThe back sends the RTH grouping.In addition, when sending the RTH grouping simultaneously for fear of a plurality of link terminals, the purpose terminal receives this RTH grouping and bumps, at back off time T AWAfter, do not send the RTH grouping if listen to other-end (satisfying the adjacent terminal of formula (1)), then send the RTH grouping.
The CA grouping that step 204, reception purpose terminal are sending when not listening to the RTH grouping, and according to this CA grouping, renewal N CA
Step 205, if N CADuring smaller or equal to default higher limit, then according to the N after upgrading CA, and formula (2), calculate the back off time T after upgrading AW
In the present embodiment, at T CWIn, if the purpose terminal does not correctly receive the RTH grouping, and do not listen to when colliding generation, then send the CA grouping with broadcast mode, compete again to announce link terminal.Each link terminal upgrades N according to the CA grouping that receives CA, and at N CADuring smaller or equal to default higher limit, with the N after upgrading CAIn the substitution formula (2), calculate the back off time T after upgrading AWBack off time T after renewal AWAfter, do not send the RTH grouping if listen to other adjacent terminals, then send the RTH grouping.Need to prove, work as N CADuring greater than default higher limit, then this link terminal withdraws from this cooperation transmission, directly transmits data between source terminal and the purpose terminal.
Need to prove, if receive the CA that the purpose terminal sends again, then repeat above-mentioned steps 204 and step 205, when the number of times of purpose terminal transmission CA has surpassed preset value, then the purpose terminal sends the CCTS grouping with the form of broadcasting, comprises direct-sending message in this CCTS grouping, is used for announcing to adopt the mode of direct transferring to carry out transfer of data, after then source terminal receives this CCTS grouping, send packet to the purpose terminal with third speed; Perhaps, the number of times of the CA that sends until the purpose terminal does not surpass this preset value, and link terminal is before sending the RTH grouping, listens to other adjacent terminals when sending RTH grouping, and then this link terminal withdraws from this cooperation transmission.
The CCTS grouping that step 206, reception purpose terminal are replied.
The packet that step 207, reception sources terminal send, and transmit this packet with second transmission rate and give the purpose terminal.
In the present embodiment, the implementation of the implementation of step 206 and step 103 shown in Figure 1 is similar, and the implementation of the implementation of step 207 and step 104 shown in Figure 1 is similar, repeats no more herein.Need to prove, after the purpose terminal correctly receives packet, with the form transmission ACK of broadcasting.After the purpose terminal did not correctly receive packet, then the form with broadcasting sent the NACK grouping, to announce to restart to send packet.When restarting to send packet, it specifically can have following two kinds of implementations:
First kind, source terminal can directly send to packet the purpose terminal, and its transmission rate is compared to the low one-level of the 3rd transmission rate.
Second kind, source terminal sends packet to link terminal compared to the low one-level of first transmission rate, and link terminal is transmitted to the purpose terminal compared to the low one-level of second transmission rate with this packet.
In the present embodiment, by arrive the first transmission rate R of adjacent terminal at source terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula
Figure BSA00000383045400101
Then according to formula
Figure BSA00000383045400102
Calculate back off time T AWIf do not listen to the preparation cooperation grouping that other adjacent terminals send, then according to back off time T AW, sending and prepare the cooperation grouping, this preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RDThe answer cooperation of replying according to the purpose terminal that receives at last sends and confirms grouping, transmit the packet of source terminal transmission to the purpose terminal, because the adjacent terminal as link terminal is according to the competition gained, therefore can react the instant situation of channel, and solved that the candidate relay terminal challenge produces the problem of collision in the prior art, thereby shortened the competition time delay effectively, and improved the throughput of transfer of data effectively.
Fig. 3 is the flow chart of another embodiment of the collaboration data transmission method of self adaptation relay selection of the present invention, as shown in Figure 3, the executive agent of present embodiment is for being adjacent terminal, and should neighbour's terminal and other adjacent terminals jump at a distance of one, in addition, this neighbour's terminal can also be referred to as candidate's link terminal, and then this method comprises:
Step 301, if the source terminal that gets access to the first transmission rate R of adjacent terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula:
R SR ≥ 2 R SD R RD ≥ 2 R SD - - - ( 1 )
Then according to formula (2):
T AW = λ 1 R SD - ( 1 R SR + 1 R RD ) - T CW * N CA - - - ( 2 )
Calculate back off time T AW
Wherein, λ is a predefined constant; N CAFor the competition that receives the transmission of purpose terminal inserts the number of times that CA divides into groups, and N CA=1; T CWBe the competition window time.
In the present embodiment, the implementation of step 301 and the implementation of step 101 shown in Figure 1 are similar, repeat no more herein.
Step 302, if do not listen to the RTH grouping that other adjacent terminals send, then according to back off time T AW, sending the RTH grouping, this RTH grouping comprises the first transmission rate R SRWith the second transmission rate R RD
In the present embodiment, can there be a plurality of adjacent terminals to satisfy formula (1), as link terminal.Each link terminal can calculate back off time T according to formula (2) AW, and at back off time T AWThe back sends the RTH grouping.In addition, send RTH grouping simultaneously for fear of a plurality of link terminals, make the purpose terminal receive this RTH grouping and bump, at back off time T AWAfter, if do not listen to other-end (satisfying the adjacent terminal of formula (1)) when sending the RTH grouping, then send the RTH grouping.
(Contention Resolve is decomposed in the competition that step 303, reception purpose terminal send; Be called for short: CR) grouping.
Step 304, if do not listen to the RTH grouping that other adjacent terminals send, then according to K the mini-slot that marks off at channel in advance, with probability Select a mini-slot to send the RTH grouping, this RTH grouping comprises first transmission rate and second transmission rate.
In the present embodiment, at T CWIn, if listening to, the purpose terminal collides when taking place, then send the CR grouping with broadcast mode, to announce that competing catabolic phase begins.Need to prove that the link terminal that only bumps enters the competition catabolic phase, other link terminals that do not bump withdraw from this cooperation transmission.The link terminal that enters the competition catabolic phase is not listening to other adjacent terminals when sending RTH grouping, according to K the mini-slot that marks off at channel in advance, with probability
Figure BSA00000383045400121
Select a mini-slot to send the RTH grouping.In addition, the link terminal that enters the competition catabolic phase listens to other adjacent terminals when sending RTH grouping, then withdraws from this cooperation transmission.
Need to prove, if the purpose terminal in the competition catabolic phase still heat listen to collision and take place, then continue to send the CR grouping, if this link terminal receives the CR that the purpose terminal sends again, then repeat above-mentioned steps 304, before sending the RTH grouping, listen to other adjacent terminals and send the RTH grouping, then withdraw from this cooperation transmission.
The CCTS grouping that step 305, reception purpose terminal are replied.
The packet that step 306, reception sources terminal send, and transmit this packet with second transmission rate and give the purpose terminal.
In the present embodiment, the implementation of the implementation of step 305 and step 103 shown in Figure 1 is similar, and the implementation of the implementation of step 306 and step 104 shown in Figure 1 is similar, repeats no more herein.Need to prove, after the purpose terminal correctly receives packet, send the ACK grouping.After the purpose terminal does not correctly receive packet, then send the NACK grouping, to announce to restart to send packet.When restarting to send packet, it specifically can have following two kinds of implementations:
First kind, source terminal can directly send to packet the purpose terminal, and its transmission rate is compared to the low one-level of the 3rd transmission rate.
Second kind, source terminal sends packet to link terminal compared to the low one-level of first transmission rate, and link terminal is transmitted to the purpose terminal compared to the low one-level of second transmission rate with this packet.
In the present embodiment, by arrive the first transmission rate R of adjacent terminal at source terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula
Figure BSA00000383045400131
Then according to formula
Figure BSA00000383045400132
Calculate back off time T AWIf do not listen to the preparation cooperation grouping that other adjacent terminals send, then according to back off time T AW, sending and prepare the cooperation grouping, this preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RDThe answer cooperation of replying according to the purpose terminal that receives at last sends and confirms grouping, transmit the packet of source terminal transmission to the purpose terminal, the candidate relay terminal challenge produces the problem of collision in the prior art thereby solved, and then shortened the competition time delay effectively, and improved the throughput of transfer of data effectively.In addition, link terminal can divide into groups according to the CR that the purpose terminal that receives sends, and reenters the competition catabolic phase, and according to K the mini-slot that marks off at channel in advance, with probability
Figure BSA00000383045400133
Select a mini-slot to send the RTH grouping, thereby participate in this cooperation transmission or withdraw from this cooperation transmission, and then solved more effectively that the link terminal competition produces the problem of collision in the prior art, and shortened the competition time delay more effectively, improved the success rate of the cooperation transmission data of link terminal effectively.
Further, in yet another embodiment of the present invention, if satisfy between the adjacent terminal of formula (1) scope at a distance of double bounce, and the purpose terminal listens to above-mentioned adjacent terminal when bumping, and this method can also comprise:
Receive the competition slot selection (Contention-Slot-Choose that the purpose terminal sends; Be called for short; CSC) grouping;
If do not listen to the CCTS grouping that the purpose terminal sends, then according to N the time slot of on channel, dividing in advance, with probability Select a time slot to send the RTH grouping, this RTH grouping comprises first transmission rate and second transmission rate.
For instance, Fig. 4 is at a distance of the network topology structure schematic diagram of double bounce, as shown in Figure 4 between the link terminal, S is for sending terminal, and D is the purpose terminal, and R1 and R2 are two link terminals of double bounce apart, the cooperation quality of cooperation mass ratio R2 of supposing R1 is good, i.e. the T of R1 AWT than R2 AWLittle.Because R1 and R2 are at a distance of double bounce, therefore, when R1 sent the RTH grouping, R2 can not listen to the RTH grouping that R1 sends; In like manner, when R2 sent the RTH grouping, R1 can not listen to the RTH grouping that R2 sends, and took place thereby can exist the purpose terminal to listen to collision.The RTH that goes out to receive when the purpose terminal judges is grouped into collision and occurs in T RTHIn time, then reply the CSC grouping.This T RTHThe expression RTH transmission packets time, refer to send RTH and divide into groups the needed time.After the link terminal that bumps receives the CSC grouping, do not send the CCTS grouping if listen to the purpose terminal, then according to N the time slot of dividing in advance on channel, wherein, the length of each time slot is T RTH, with probability Select a time slot to send the RTH grouping.Send the CCTS grouping if listen to the purpose terminal, then withdraw from this cooperation transmission.
In the present embodiment, N can be 4, need to prove, when the collision link terminal more for a long time, the number of timeslots of Hua Fening also can increase thereupon in advance.Concrete, the length of each time slot can equal T RTH
In the present embodiment, because the purpose terminal receives that the time that RTH is grouped into collision is no more than T RTH, the back off time T of each link terminal that namely bumps AWDifference can not surpass T RTH, therefore, the cooperation quality of link terminal is more or less the same, and terminal (namely participating in the link terminal of this cooperation transmission) quality that final competition is won can be too not poor yet, thereby improved the throughput of transfer of data more effectively.
Fig. 5 is the structural representation of an embodiment of the collaboration data transmission system of self adaptation relay selection of the present invention, as shown in Figure 5, the data transmission system of present embodiment comprises: source terminal 11, purpose terminal 12 and adjacent terminal 13, wherein, adjacent terminal comprises: back off time computing module 131, RTH grouping sending module 132, CCTS grouping receiver module 133 and forwarding module 134.Wherein, back off time computing module 131 is used for if the source terminal that gets access to arrives the first transmission rate R of adjacent terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula Then according to formula
Figure BSA00000383045400143
Calculate back off time T AWThe one RTH grouping sending module 132 is used for if do not listen to the RTH grouping that other adjacent terminals send, then according to back off time T AW, sending the RTH grouping, the RTH grouping comprises first transmission rate and second transmission rate; CCTS grouping receiver module 133 is used for receiving the CCTS grouping that the purpose terminal is replied; Forwarding module 134 is used for the packet that the reception sources terminal sends, and transmits packet with second transmission rate and give the purpose terminal.
Wherein, λ is a predefined constant; N CAInsert the number of times of grouping for the competition that receives described purpose terminal transmission; T CWBe the competition window time.
The terminal of present embodiment can be used for carrying out the technical scheme of method embodiment shown in Figure 1, and it realizes that principle is similar, repeats no more herein.
In the present embodiment, by arrive the first transmission rate R of adjacent terminal at source terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula
Figure BSA00000383045400151
Then according to formula
Figure BSA00000383045400152
Calculate back off time T AWIf do not listen to the preparation cooperation grouping that other adjacent terminals send, then according to back off time T AW, sending and prepare the cooperation grouping, this preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RDThe answer cooperation of replying according to the purpose terminal that receives at last sends and confirms grouping, transmit the packet of source terminal transmission to the purpose terminal, the candidate relay terminal challenge produces the problem of collision in the prior art thereby solved, and then shortened the competition time delay effectively, and improved the throughput of transfer of data effectively.
Fig. 6 is the structural representation of another embodiment of the collaboration data transmission system of self adaptation relay selection of the present invention, on the basis of the technical scheme of above-mentioned embodiment shown in Figure 5, further, this neighbour's terminal comprises that also CA receives update module 135, be used for receiving the CA that the purpose terminal sends when not listening to the RTH grouping, and according to this CA, upgrade N CA, then if back off time computing module 131 specifically is used for N VADuring smaller or equal to default higher limit, then according to the N after upgrading CA, and formula
Figure BSA00000383045400161
Calculate the back off time T after upgrading AW
The terminal of present embodiment can be used for carrying out the technical scheme of method embodiment shown in Figure 2, and it realizes that principle is similar, repeats no more herein.
In the present embodiment, by arrive the first transmission rate R of adjacent terminal at source terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula
Figure BSA00000383045400162
Then according to formula
Figure BSA00000383045400163
Calculate back off time T AWIf do not listen to the preparation cooperation grouping that other adjacent terminals send, then according to back off time T AW, sending and prepare the cooperation grouping, this preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RDThe answer cooperation of replying according to the purpose terminal that receives at last sends and confirms grouping, transmit the packet of source terminal transmission to the purpose terminal, because the adjacent terminal as link terminal is according to the competition gained, therefore can react the instant situation of channel, and solved that the candidate relay terminal challenge produces the problem of collision in the prior art, thereby shortened the competition time delay effectively, and improved the throughput of transfer of data effectively.
Fig. 7 is the structural representation of another embodiment of the collaboration data transmission system of self adaptation relay selection of the present invention, on the basis of the technical scheme of above-mentioned embodiment shown in Figure 5, this neighbour's terminal 13 also comprises CR receiver module 136 and the 2nd RTH sending module 137, wherein, CR receiver module 136 is used for receiving the CR grouping that the purpose terminal sends; The 2nd RTH sending module 137 is used for not sending the RTH grouping if listen to other adjacent terminals, then according to K the mini-slot that marks off at channel in advance, with probability
Figure BSA00000383045400164
Select a mini-slot to send the RTH grouping, this RTH grouping comprises first transmission rate and second transmission rate.
The terminal of present embodiment can be used for carrying out the technical scheme of method embodiment shown in Figure 3, and it realizes that principle is similar, repeats no more herein.
In the present embodiment, by arrive the first transmission rate R of adjacent terminal at source terminal SR, adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of source terminal to the purpose terminal SDSatisfy formula Then according to formula
Figure BSA00000383045400172
Calculate back off time T AWIf do not listen to the preparation cooperation grouping that other adjacent terminals send, then according to back off time T AW, sending and prepare the cooperation grouping, this preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RDThe answer cooperation of replying according to the purpose terminal that receives at last sends and confirms grouping, transmit the packet of source terminal transmission to the purpose terminal, the candidate relay terminal challenge produces the problem of collision in the prior art thereby solved, and then shortened the competition time delay effectively, and improved the throughput of transfer of data effectively.In addition, link terminal can divide into groups according to the CR that the purpose terminal that receives sends, and reenters the competition catabolic phase, and according to K the mini-slot that marks off at channel in advance, with probability
Figure BSA00000383045400173
Select a mini-slot to send the RTH grouping, thereby participate in this cooperation transmission or withdraw from this cooperation transmission, and then solved more effectively that the link terminal competition produces the problem of collision in the prior art, and shortened the competition time delay more effectively, improved the success rate of the cooperation transmission data of link terminal effectively.
Fig. 8 is the also structural representation of an embodiment of the collaboration data transmission system of self adaptation relay selection of the present invention, on the basis of the technical scheme of above-mentioned embodiment shown in Figure 5, if satisfy formula
Figure BSA00000383045400174
Adjacent terminal between at a distance of the scope of double bounce, and the purpose terminal listens to above-mentioned adjacent terminal when bumping, this neighbour's terminal 13 can also comprise CSC grouping receiver module 138 and the 3rd RTH grouping sending module 139, wherein, CSC grouping receiver module 138 is used for receiving the CSC grouping that the purpose terminal sends; The 3rd RTH grouping sending module 139 is used for if do not listen to the CCTS grouping that the purpose terminal sends, then according to N the time slot of dividing in advance on channel, with probability Select a time slot to send the RTH grouping, this RTH grouping comprises first transmission rate and second transmission rate.
The terminal of present embodiment can be based on network topology structure schematic diagram shown in Figure 4, and the RTH that goes out to receive when the purpose terminal judges is grouped into collision and occurs in T RTHIn time, then reply the CSC grouping.This T RTHThe expression RTH transmission packets time.After the link terminal that bumps receives the CSC grouping by CSC grouping receiver module 19,, the 3rd RTH grouping sending module 139 does not send the CCTS grouping if listen to the purpose terminal, then according to N the time slot of dividing in advance on channel, with probability
Figure BSA00000383045400181
Select a time slot to send the RTH grouping to source terminal and purpose terminal respectively.Send the CCTS grouping if listen to the purpose terminal, then withdraw from this cooperation transmission.
In the present embodiment, N can be 4, need to prove, when the collision link terminal more for a long time, the number of timeslots of Hua Fening also can increase thereupon in advance.Concrete, the length of each time slot can equal T RTH
In the present embodiment, because the purpose terminal receives that the time that RTH is grouped into collision is no more than T RTH, the back off time T of each link terminal that namely bumps AWDifference can not surpass T RTH, therefore, the cooperation quality of link terminal is more or less the same, and terminal (namely participating in the link terminal of this cooperation transmission) quality that final competition is won can be too not poor yet, thereby improved the throughput of transfer of data more effectively.
One of ordinary skill in the art will appreciate that: all or part of step that realizes said method embodiment can be finished by the relevant hardware of program command, aforesaid program can be stored in the computer read/write memory medium, this program is carried out the step that comprises said method embodiment when carrying out; And aforesaid storage medium comprises: various media that can be program code stored such as ROM, RAM, magnetic disc or CD.
It should be noted that at last: above embodiment only in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment puts down in writing, and perhaps part technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the spirit and scope of various embodiments of the present invention technical scheme.

Claims (8)

1. the collaboration data transmission method of a self adaptation relay selection is characterized in that, comprising:
If the source terminal that gets access to is to the first transmission rate R of adjacent terminal SR, described adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of described source terminal to described purpose terminal SDSatisfy formula
Figure RE-FDA00003036867800011
Then according to formula
Figure RE-FDA00003036867800012
Calculate back off time T AW
Do not send preparation cooperation grouping if listen to other adjacent terminals, then according to described back off time T AW, to send for respectively described source terminal and purpose terminal and prepare the cooperation grouping, described preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RD
Receive the cooperation transmission affirmation grouping that described purpose terminal is replied;
Receive the packet that described source terminal sends, and with the second transmission rate R RDTransmit described packet and give described purpose terminal;
Wherein, λ is a predefined constant; N CAInsert the number of times of grouping for the competition that receives described purpose terminal transmission; T CWBe the competition window time.
2. the collaboration data transmission method of self adaptation relay selection according to claim 1 is characterized in that, also comprises:
Receive the described competition that described purpose terminal sending and insert grouping when not listening to described preparation cooperation grouping, and insert grouping according to described competition, upgrades describedly receiving the competition that described purpose terminal sends and insert the number of times that divides into groups;
Then described according to formula
Figure DEST_PATH_FDA00003036867800013
Calculate back off time T AWComprise: if the number of times that described competition inserts grouping during smaller or equal to default higher limit, then inserts the number of times of grouping according to the described competition after upgrading, and formula
Figure FSA00000383045300021
Calculate the back off time T after upgrading AW
3. the collaboration data transmission method of self adaptation relay selection according to claim 1 is characterized in that, when described adjacent terminal and the jumping apart of other adjacent terminals, this method also comprises:
Receive the competition decomposition grouping that described purpose terminal sends;
Do not send preparation cooperation grouping if listen to other adjacent terminals, then according to K the mini-slot that marks off at channel in advance, with probability Select a mini-slot to send and prepare the cooperation grouping, described preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RD
4. the collaboration data transmission method of self adaptation relay selection according to claim 1 is characterized in that, when described adjacent terminal and other adjacent terminals during at a distance of double bounce, this method also comprises:
Receive the competition slot selection grouping that described purpose terminal sends;
If do not listen to the cooperation transmission affirmation grouping that described purpose terminal sends, then according to N the time slot of on channel, dividing in advance, with probability
Figure FSA00000383045300023
Select a time slot to send and prepare the cooperation grouping, described preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RD
5. the collaboration data transmission system of a self adaptation relay selection comprises source terminal, purpose terminal and adjacent terminal, it is characterized in that, described adjacent terminal comprises:
The back off time computing module is used for if the source terminal that gets access to arrives the first transmission rate R of adjacent terminal SR, described adjacent terminal is to the second transmission rate R of purpose terminal RDWith the three transmission rate R of described source terminal to described purpose terminal SDSatisfy formula
Figure FSA00000383045300024
Then according to formula
Figure FSA00000383045300025
Calculate back off time T AW
The first preparation cooperation grouping sending module is used for preparing the cooperation grouping if listen to other adjacent terminals transmissions, then according to described back off time T AW, to send for respectively described source terminal and purpose terminal and prepare the cooperation grouping, described preparation cooperation grouping comprises the described first transmission rate R SRWith the second transmission rate R RD
The grouping receiver module is confirmed in the cooperation transmission, sends for the cooperation that receives described purpose terminal answer and confirms to divide into groups;
Forwarding module is used for receiving the packet that described source terminal sends, and transmits described packet with second transmission rate and give described purpose terminal;
Wherein, λ is a predefined constant; N CAInsert the number of times of grouping for the competition that receives described purpose terminal transmission; T CWBe the competition window time.
6. the collaboration data transmission system of self adaptation relay selection according to claim 5 is characterized in that, described adjacent terminal also comprises:
Competition inserts grouping and receives update module, do not listening to the described competition access grouping that sends when described preparation cooperation is divided into groups for receiving described purpose terminal, and according to described competition access grouping, upgrade the number of times that the described competition that receives described purpose terminal transmission inserts grouping;
Then described back off time computing module specifically is used for if the number of times that described competition inserts grouping during smaller or equal to default higher limit, then inserts the number of times of grouping according to the described competition after upgrading, and formula
Figure RE-FDA00003036867800021
Calculate the back off time T after upgrading AW
7. the collaboration data transmission system of self adaptation relay selection according to claim 5 is characterized in that, when described adjacent terminal and the jumping apart of other adjacent terminals, described adjacent terminal also comprises:
The grouping receiver module is decomposed in competition, decomposes grouping for the competition that the described purpose terminal of reception sends;
The second preparation cooperation grouping sending module is used for preparing the cooperation grouping if listen to other adjacent terminals transmissions, then according to K the mini-slot that marks off at channel in advance, with probability
Figure RE-FDA00003036867800022
Select a mini-slot to send and prepare the cooperation grouping, described preparation cooperation grouping comprises described first transmission rate and second transmission rate.
8. the collaboration data transmission system of self adaptation relay selection according to claim 5 is characterized in that, when described adjacent terminal and other adjacent terminals during at a distance of double bounce, described adjacent terminal comprises:
Competition slot is selected the grouping receiver module, and the competition slot that is used for the described purpose terminal transmission of reception is selected grouping;
The 3rd prepares the sending module that divides into groups that cooperates, and is used for if do not listen to the cooperation transmission affirmation grouping that described purpose terminal sends, then according to N the time slot of dividing in advance on channel, with probability
Figure FSA00000383045300041
Select a time slot to send and prepare the cooperation grouping, described preparation cooperation grouping comprises described first transmission rate and second transmission rate.
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