CN103078795A - Cooperation routing method for improving wireless network throughput capacity - Google Patents

Abstract

The invention belongs to the field of wireless communication, and is mainly applied to a wireless self-organizing network. On the premise of not increasing the network energy consumption, the throughput capacity of the whole routing path is effectively improved through maximizing the network throughput capacity of each hop of links. In order to reach the goal, a method provided by the invention adopts the technical scheme that according to a cooperation routing method for improving the wireless network throughput capacity, a source node transmits data to a target node through multiple hops, an emitting node of each hop of link firstly builds a non-cooperation shortest path route, and in addition, a candidate relay node set is built through a built route list and a neighbor node list; then, the link throughput capacity under the direct transmission, single-relay cooperation transmission and double-relay cooperation transmission is calculated, and the transmission mode corresponding to the maximum throughput capacity is selected in a self-adaptive way to be used as the transmission mode of the hop of link; and finally, the power is dynamically regulated according to the selected transmission mode, in addition, the data grouped transmission is carried out until the data of the source node is transmitted to the target node.

Description

Improve the cooperative routing method of throughput of wireless networks

Technical field

The invention belongs to wireless communication field, particularly a kind of cooperation route technology that is applied to wireless self-networking specifically, relates to the adaptive cooperation method for routing that improves the wireless self-organization network throughput.

Background technology

Along with the development of wireless communication technology, Mobile data and information service dramatic growth.Especially along with intelligent terminal and multiple mobile extensively popularizing of using, therefore people have higher requirement to wireless network performance indexs such as network throughputs to the demand rapid growth of wireless data service.Yet on the one hand, in the mobile communication of reality, portable terminal usually works in architecture ensemble or other geographical environment complicated and changeable, and complicated geomorphological features is so that the signal that receiving terminal receives generally can suffer the impacts such as multipath fading, shadow fading.This decline meeting causes the communication system error rate to raise so that reception signal serious distortion and distortion reduce signal power.On the other hand, the relative wire message way of wireless network bandwidth is much lower.Along with developing rapidly of mobile Internet, the radio network information flow increases rapidly, so that wireless network bandwidth is not enough, bandwidth resources are more rare, and these raisings to the throughput of wireless networks performance have all formed very large obstruction.

In wireless network, Design of Routing Protocol is very important, and wherein the shortest path Routing Protocol is a kind of common routing protocol in the wireless self-organization network, and it can shorten the distance of transfer of data, promotes the speed of transfer of data.Plane shortest path Routing Protocol can be divided into two kinds, is respectively on-demand routing protocol and proactive routing protocol.Particularly, on-demand routing protocol is also referred to as the reaction equation Routing Protocol, and this quasi-protocol did not generate route before receiving request, and when network sends the transmission request, just begins to search for the route of setting up from the source node to the destination node.Therefore, the routing iinformation of system is set up as required, and it only reflects the part of whole network topology structure information.Route generally comprises route discovery and two stages of route maintenance as required, and this agreement comprises wireless self-networking as required plan range vector Routing Protocol (AODV), dynamic source routing protocol (DSR), interim routing algorithm (TORA) etc. according to the order of sequence.And for proactive routing protocol, claiming again table to drive Routing Protocol, routing table of each node maintenance is recorded to the routing iinformation of each node.The grouping of the periodic broadcast of node, exchanging routing information each other between node.When network topology changed, node broadcasts routing update grouping was spread all over whole network to this updating message, and node upgrades the routing table of oneself according to update packet, thereby obtains up-to-date network topological information.Therefore, in a single day source node needs to send message, can accurately obtain to arrive immediately the route of destination node.This agreement comprises aim sequence distance vector routing protocol (DSDV), Fisheye Domain Routing Protocol (FSR), optimization link-state routing protocol (OLSR) etc.

In order to improve the performance of mobile communication system, can adopt cooperative communication technology to improve the quality that receives signal.Portable terminal can be chosen in other one or more portable terminals that are in idle condition of current time slots and assist transmission information in wireless cooperative network, in the process of transmission information, not only utilized oneself but also the space channel that utilized the cooperation portable terminal of this portable terminal, by sharing antenna each other, obtain diversity gain.Receive a plurality of copies that carry identical information that different channels transmits at receiving terminal, recover original signal by certain signal processing technology.Because the transmission characteristic of a plurality of channels is different, the signal copy that receives has the fading characteristic of independence, therefore can in the situation that does not increase system resource, greatly reduce the impact of decline, enlarge coverage, raising transmission reliability, the reduction transmitting power of wireless network, thereby improve wireless network performance.

Further, cooperative diversity technique and Route Selection can be combined, design is based on the routing algorithm of collaboration communication, and routing algorithm namely cooperates.Routing algorithm two classes that roughly can be divided at present, Energy Efficient and peak optimizating network service quality (QoS) for the research of cooperation routing algorithm.Particularly, for the routing algorithm of Energy Efficient, main thought is to set up the cooperation route according to certain rule in wireless network, makes the power of system consumption minimum; The routing algorithm of optimization QoS then reaches the purpose of optimized communication system QoS by setting up the cooperation route.Along with business such as the appearance such as real-time multimedia service, the networking telephone of in the network QoS being strict with, need mobile wireless network can provide corresponding QoS to ensure, so design optimization QoS routing algorithm is significant.But the dynamic change of the mobility of mobile wireless network node, the finiteness of network bandwidth resources, network topology structure, the computing capability of mobile node and the characteristics such as memory capacity is lower, energy constraint have formed challenge to the cooperation Design of Routing Algorithm of optimization QoS.Especially owing to the mobility of network node, network topology constantly changes, and the via node that before participates in cooperation may leave the collaboration communication scope, thereby causes synergistic link to lose efficacy.The cooperation route need to select suitable via node to participate in cooperation by real-time channel conditions when selecting via node.

Summary of the invention

The present invention is intended to overcome the deficiencies in the prior art, proposes a kind of adaptive cooperation route transmission method that improves throughput of wireless networks, to improve the transmission performance of wireless network.The technical scheme that the present invention takes is, improve the cooperative routing method of throughput of wireless networks, comprise the steps: that the basic enterprising step of advancing in the non-cooperation shortest path of multi-hop route is by selection, the transfer of data that the mode of source node by multi-hop will need to send is to destination node, the stage by stage transmission three phases of the foundation of every jumping link experience candidate relay node set, transmission mode selection and packet, in the phase I, according to the non-cooperation multi-hop routed path of having set up, the transmitting node x of every jumping link _iSet up candidate relay node set Ω by the routing table and the neighbor node table that have established _iSecond stage, the transmitting node x of current link _iTravel through all transmission modes, calculate in these three kinds of Basic Transmission Unit of direct transmission, single relay cooperative transmission and two relay cooperative transmission and have the transmission mode of maximum link throughput as the final transmission mode of current link, and select node in the corresponding candidate relay node set as via node; In the phase III, transmitting node x _iParticipate in the transmitting power of the node of this link data transmission according to the link transmission pattern dynamic assignment of final selection, and carry out transfer of data, if the transmission mode of maximum link throughput is direct transmission, then this transmitting node x _iMode by direct transmission sends data to the receiving node z when the skip before link _iIf the transmission mode of maximum link throughput is cooperation transmission, this transmitting node x then _iAccording to result of calculation from candidate relay set Ω _iIn select corresponding via node and assist transmitting node x _iTo receiving node z _iTransmission information.

The routing algorithm that the present invention proposes is made of direct transmission, single relay cooperative transmission and three kinds of basic link transmission units of two relay cooperative transmission; Source node s jumps transfer of data to destination node d by n, and wherein the i(1≤i≤n) jumps the transmitting node x of institute's respective links _iSelect direct transmission mode, single relay cooperative transmission pattern or two relay cooperative transmission pattern with the receiving node z of transfer of data to this jumping link _iParticularly, directly transmission mode is the transmitting node x of current link _iBy the mode that direct transfers with transfer of data to receiving node z _i, by (x _i, z _i) representing this link, the throughput of this link is designated as

Single relay cooperative transmission pattern is the transmitting node x of current link _iFrom candidate relay node set Ω _iNode of middle selection is as via node r _iAssist transmitting node x _iTransmit data to receiving node z _i, by (x _i, r _i, z _i) representing this link, the throughput of this link is designated as

The transmitting node x that two relay cooperative transmission patterns are current link _iFrom candidate relay node set Ω _iTwo nodes of middle selection are as via node r _i ¹And r _i ²Assist transmitting node x _iTransmit data to receiving node z _i, by (x _i, r _i ^1,r _i ², z _i) representing this link, the throughput of this link is designated as

The realization of routing algorithm comprises following steps successively:

Step 1 is utilized the multi-hop shortest path route of non-cooperation shortest-path rout ing algorithms structure from source node s to destination node d in wireless network, each node in this routed path is set up also routing table and the neighbors table of real-time update self, jumps the transmitting node x of link as i=1 with seasonal source node s ₁

Step 2 i jumps the transmitting node x of link _iInquire about the neighbors table of self, acquisition can with transmitting node x _iCan jump with this again the receiving node z of link _iAll nodes that communicate, the set that these nodes form is the candidate relay node set Ω of this jumping link _i

Step 3 i jumps the transmitting node x of link _iTraversal candidate relay set Ω _iIn all nodes, calculate the throughput under the direct transmission mode of this jumping link

Throughput under all possible single relay transmission pattern And the throughput under two relay transmission patterns Concrete operations are as follows:

Step 3.1 i jumps the transmitting node x of link _iCalculate direct transmission link (x _i, z _i) link throughput

${\mathrm{\η}}_{x_i,z_i}=\exp (-\frac{(2^{R_0}-1)N_0{d}_{x_i,z_i}^{\mathrm{\α}}}{P^{\max }})\×R_0$

Wherein, P ^MaxBe transmitting node x _iTransmitting power,

Transmitting node x for current link _iWith receiving node z _iBetween distance, α is the path loss factor, R ₀Be information transmission rate, N ₀Be noise; Further, transmitting node x _iDetect candidate relay set Ω _iWhether be empty, if empty, then set the maximum throughput of single relay cooperative transmission link

Maximum throughput with two relay cooperative links

Be zero, and execution in step 4, if be not empty, then execution in step 3.2;

Step 3.2 i jumps the transmitting node x of link _iTraversal candidate relay set Ω _iIn all via nodes as the situation of single relay cooperative transmission pattern, calculate single relay cooperative transmission link (x _i, r _i, z _i) corresponding link throughput

${\mathrm{\η}}_{x_i,r_i,z_i}=(\exp (-g{d}_{x_i,z_i}^{\mathrm{\α}})+\exp (-g{d}_{x_i,r_i}^{\mathrm{\α}}-g{d}_{r_i,z_i}^{\mathrm{\α}})-\exp (-g{d}_{x_i,r_i}^{\mathrm{\α}}-g{d}_{r_i,z_i}^{\mathrm{\α}}-g{d}_{x_i,z_i}^{\mathrm{\α}}))\×R_0$

Wherein, Single relay cooperative transmission pattern lower node x _iAnd r _iTransmitting power equate to be

Be transmitting node x _iWith destination node z _iBetween distance, Be transmitting node x _iWith via node r _iBetween distance,

Be via node r _iWith destination node z _iBetween distance, α is the path loss factor, R ₀Be information transmission rate, N ₀Be noise; Pass through formula

Calculate the throughput of maximum single relay cooperative transmission link While transmitting node x _iDetect candidate relay set Ω _iMiddle candidate relay node number if candidate relay node number is less than two, is then set

Equal zero, and execution in step 4, otherwise, execution in step 3.3;

Step 3.3 i jumps the transmitting node x of link _iTravel through all candidate relay nodes that make up in twos as two relaying r _i ¹And r _i ²Cooperation transmission the time situation, calculate two relay cooperative transmission link (x _i, r _i ¹, r _i ², z _i) link throughput

${\mathrm{\&eta;}}_{x_i,r_i^1,r_i^2,z_i}=(\exp (-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_{i1}^1,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-\mathrm{<figure-callout\; id="2"\; label="g\; d\; r"\; filenames="HDA00002693283800051.png"\; state="\{\{state\}\}">g</figure-callout>}{d}_{r_{}}^{}{{}_2,z_i}_{\mathrm{\&alpha;}}^{})$

$-\exp (-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_i^1,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_i^2,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})$

$-\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_i^2,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_i^1,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_i^2,z_i}^{\mathrm{\&alpha;}}$

$-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_i^1,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}}\left)\right)\&times;R_0$

Wherein,

Two relay cooperative transmission pattern lower node x _i, r _i ¹And r _i ²Transmitting power equate to be

Be transmitting node x _iWith destination node z _iBetween distance,

Be transmitting node x _iWith via node r _i ^j, Between distance,

Be via node r _i ^jWith destination node z _iBetween distance, α is the path loss factor, R ₀Be information transmission rate, N ₀Be noise; Utilize formula

Calculate the throughput of maximum two relay cooperative transmission links

The throughput of the more direct transmission link of step 4

The throughput of maximum single relay cooperative transmission link

Throughput with maximum two relay cooperative transmission links Size, maximum wherein is set as the maximum η of current link throughput ^MaxIf link throughput corresponding to link under the direct transmission mode

Maximum, then execution in step 5; If link throughput corresponding to link under single relay cooperative transmission pattern

Maximum, then execution in step 6; If link throughput corresponding to link under two relay cooperative transmission patterns

Maximum, then execution in step 7;

Step 5 is set current transmitting node x _iTransmitting power be maximum transmission power P ^Max, adopt direct mode to transfer data to receiving node z _i, and execution in step 8;

The current transmitting node x of step 6 _iForward packets to receiving node z by selected via node with single relay cooperative transmission pattern _i, specific operation process is as follows:

Step 6.1 is with the link maximum throughput

Corresponding candidate relay node r _iAs the single via node r that chooses _i ^s

Step 6.2 is with current transmitting node x _iWith via node r _i ^sTransmitting power all be set as half of maximum transmission power, i.e. P ^Max/ 2;

The current transmitting node x of step 6.3 _iAt first time slot with transmitting power P ^Max/ 2 broadcast data packets, via node r _i ^sWith receiving node z _iReceive the data that transmitting node sends;

Step 6.4 via node r _i ^sTo the decoding data that receives, if the received signal to noise ratio of signal, is then thought via node r this moment greater than a specific thresholding _i ^sCan correctly receive transmitting node x _iSend data, i.e. successfully decoded, then at the second time slot with transmitting power P ^Max/ 2 transmit transmitting node x _iData to receiving node z _i, and execution in step 8; If received signal to noise ratio less than specific threshold value, is then thought and is decoded unsuccessfully, abandon this packet, and execution in step 8;

The current transmitting node x of step 7 _iSelect two relay cooperative transmission patterns to forward packets to receiving node z _i, specific operation process is as follows:

The current transmitting node x of step 7.1 _iWill

Two corresponding candidate relay nodes

With

As two via nodes choosing

With

Step 7.2 couple current transmitting node x _iWith two via nodes

With

Carry out power setting, the transmitted power of these three nodes all is set as 1/3rd of maximum transmission power, i.e. P ^Max/ 3;

The current transmitting node x of step 7.3 _iAt first time slot with transmitting power P ^Max/ 3 broadcast data packets, via node

With And receiving node z _iReceive this data;

Step 7.4 via node

With

To the decoding data that receives, if via node

With

The received signal to noise ratio that detects is greater than a specific thresholding, then thinks via node this moment

With Can correctly receive transmitting node x _iThe transmission data, i.e. successfully decoded is then at the second time slot via node With

Respectively with transmitting power P ^Max/ 3 transmit from transmitting node x _iData to receiving node z _i, and execution in step 8; Otherwise think and decode unsuccessfully, abandon this packet, and execution in step 8;

Step 8 receiving node z _iTo the decoding data that receives, if receiving node z _iCorrectly received transmitting node x _iOr the via node r that selects under single relay cooperative transmission pattern _i ^sOr the via node of selecting under two relay cooperative transmission patterns

With The signal of sending, then execution in step 9; Otherwise the route data bust this finishes this route data transmission;

Step 9 is judged receiving node z _iWhether be the destination node d of routed path, if not, then current i is jumped the receiving node z of link _iJump the transmitting node x of link as i+1 _I+1, and return execution in step 2; If receiving node z _iBe the destination node d of routed path, then the route transmission data are successful, finish the transmission course of this routed path.

Technical characterstic of the present invention and effect are as follows: the cooperative routing method of the raising throughput of wireless networks that the present invention proposes can be adapted to the wireless network of dynamic change, improves the throughput performance of network under the condition that does not increase system power dissipation.Particularly, the first, this cooperation route transmission method is the situation of change of sensing network topology in time, the wireless network that the flexible adaptation topological structure constantly changes; The second, the node in the route has been avoided consuming excessively of system capacity according to the adaptive knot modification transmitting power of s own situation; The 3rd, at every jumping link of adaptive cooperation route by comprehensively selecting and relatively, the link of selecting to set up throughput the best carries out communication, the Effective Raise network throughput.

Description of drawings

Fig. 1 is the mode figure that improves the cooperative routing method of throughput of wireless networks.

Fig. 2 is the structure of neighbors table.

Fig. 3 is the process of adaptively selected transmission mode.

Fig. 4 is the cooperation transmission process of packet.

Fig. 5 is that throughput is with the change curve of maximum transmission power.

Fig. 6 is that throughput is with the change curve of network node number.

Fig. 7 is that throughput is with the change curve of node maximum movement speed.

Embodiment

The present invention is based on proactive routing protocol and obtain up-to-date network topological information, with collaboration diversity and the abundant combination of route technology, thereby improve network throughput.The object of the invention is to propose a kind of adaptive cooperation route transmission method that improves throughput of wireless networks, to improve the transmission performance of wireless network.The method is based on multi-hop transmission, and namely the mode of source node s by the multi-hop transfer of data that will need to send is to destination node d, and wherein each jumps the transmitting node x in link _iSelect direct transmission mode, single relay cooperative transmission pattern or two relay cooperative transmission pattern with the receiving node z of transfer of data to this link according to current network conditions _i, realize to improve the purpose of whole network throughput by the throughput that improves every jumping link.

The cooperative routing method that the present invention is designed can under the condition that does not increase system power dissipation, significantly promote the throughput performance of wireless network.In this invention, with link throughput as the foundation of setting up route, by calculating the link throughput of more direct transmission mode link throughput, all possible single relay transmission pattern and two relay transmission patterns, select the transmission mode of throughput maximum to carry out transfer of data, so that the every jumping link in the final route of setting up all has maximum throughput, thereby promote the throughput performance of whole routed path.Because in the cooperation transmission link, transmitting node and via node all need to send packet, for the consumption of control system energy, make total transmitting power of every jumping synergistic link be not more than total transmitting power of direct transmission link.Therefore, when adopting the synergistic link transmission, the transmitting power of node in the link is reset, thereby avoid consuming excessively of nodes energy.

The adaptive cooperation method for routing that the present invention proposes is based on non-cooperation shortest-path rout ing algorithms, the Route Selection that cooperates on the basis of setting up multi-hop shortest path route, the implementation of every jumping link comprises the stage by stage transmission three phases of the foundation of candidate relay node set, transmission mode selection and packet.The below is established to the whole process of finishing transfer of data according to the implementation of this three phases to route and describes in detail.

Phase I: the foundation of candidate relay node set.Particularly, at first utilize non-cooperation shortest-path rout ing algorithms to make up multi-hop shortest path route from source node s to destination node d, all nodes on this routed path all need to safeguard a routing table and a neighbors table, when network topology structure changes, all nodes in this path upgrade in time separately routing table and neighbors table, simultaneously broadcasting contains the update packet of latest network information, and each node receives after the update packet that other node sends and can upgrade in time and safeguard oneself routing table and neighbors table according to grouping information.Further, the transmitting node x of each jumping on this shortest path route _iInquire about the neighbors table of self, according to this neighbors table obtain can with transmitting node x _iCan jump with this again the receiving node z of link _iAll nodes that communicate, these nodes consist of the candidate relay node set Ω of this jumping link _i, every jumping link carries out follow-up transmission mode selection based on this via node set.

Second stage: the selection of transmission mode comprises the link throughput of calculating under the various transmission modes and selects to determine the link transmission pattern.Particularly, the transmitting node x in the skip before link at first _iUtilize formula

${\mathrm{\&eta;}}_{x_i,z_i}=\exp (-\frac{(2^{R_0}-1)N_0{d}_{x_i,z_i}^{\mathrm{\&alpha;}}}{P^{\max }})\&times;R_0$

Calculating is from transmitting node x _iTo receiving node z _iThe throughput of direct transmission link

Transmitting node x in every jumping link _iTraversal search candidate relay set Ω _iIn all via nodes, utilize formula

${\mathrm{\&eta;}}_{x_i,r_i,z_i}=(\exp (-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i}^{\mathrm{\&alpha;}}-g{d}_{r_i,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i{,r}_i}^{\mathrm{\&alpha;}}-g{d}_{r_i,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}}))\&times;R_0$

Calculate successively the link throughput of single relay transmission pattern And relatively obtain maximum single repeated link throughput

Transmitting node x in every jumping link _iTraversal search candidate relay set Ω _iIn all via nodes, utilize formula

${\mathrm{\&eta;}}_{x_i,r_i^1,r_i^2,z_i}=(\exp (-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_{i1}^1,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-\mathrm{<figure-callout\; id="2"\; label="g\; d\; r"\; filenames="HDA00002693283800051.png"\; state="\{\{state\}\}">g</figure-callout>}{d}_{r_{}}^{}{{}_2,z_i}_{\mathrm{\&alpha;}}^{})$

$-\exp (-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_i^1,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})-\exp (-g{d}_{x_i{,r}_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_i^2,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})$

$-\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_i^2,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_i^l,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_i^2,z_i}^{\mathrm{\&alpha;}}$

$-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_i^1,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}}\left)\right)\&times;R_0$

Calculate successively the link throughput of the two relay transmission patterns under per two via nodes combination

And relatively obtain maximum two repeated link throughputs

Then, the transmitting node x of every jumping link _iAccording to the link throughput under the direct transmission that calculates Maximum single repeated link throughput

With the single repeated link throughput of maximum

Relatively obtain the maximum throughput η of this jumping link ^Max, and select maximum throughput η ^MaxCorresponding transmission mode is as the final data transmission mode of current link.If select direct transmission mode, then this link will adopt non-cooperation transmission pattern to carry out transfer of data; If select single relay cooperative transmission pattern, then with maximum throughput

Corresponding via node is elected the via node r that assists the transmitting node the transmission of data as _i ^sIf select two relay cooperative transmission patterns, then with maximum throughput

Corresponding a pair of via node is elected the via node of assisting the transmitting node the transmission of data as

With

Phase III: the transmission of packet comprises power setting and the transfer of data of node.According to direct transmission, single relay cooperative transmission or the two relay cooperative transmission pattern selected, the transmitting node of current link is at first set the transmitted power of sending node, then carries out transfer of data according to the transmitted power of setting.

If the direct transmission mode of current link selection is set transmitting node x _iTransmitting power be maximum transmission power P ^Max, transmitting node x _iAccording to power P ^MaxIf broadcast data packets is receiving node z _iReceive correct information, then should jump the transfer of data success of link; Otherwise should jump the data transmission fails of link, routing procedure finishes.

If current link selection single node cooperation transmission pattern is at first set the transmitting node x of this link _iWith the via node r that chooses _i ^sTransmitting power be half of maximum transmission power, i.e. P ^Max/ 2; Then transmitting node x _iAccording to the transmitting power broadcast data packets of setting, if the via node r that chooses _i ^sCan correctly receive transmitting node x _iThe data of broadcasting are then according to the receiving node z of the power of setting to current link _iForwarding data grouping, otherwise via node r _i ^sDo not participate in cooperation transmission.If receiving node z _iCan correctly recover transmitting node x _iData, then should jump transfer of data success of link; Otherwise should jump the data transmission fails of link, routing procedure finishes.

If current link selection binode cooperation transmission pattern is at first set the transmitting node x of this link _iWith the via node of choosing

With

Transmitting power be 1/3rd of maximum transmission power, i.e. P ^Max/ 3; Then, transmitting node x _iAccording to the transmitting power broadcast data packets of setting, if via node

With Can correctly receive transmitting node x _iThe data of broadcasting then will be correctly decoded data retransmission to the receiving node z of current link according to the power of setting _i, can't correctly receive transmitting node x _iThe via node of the packet of broadcasting does not then participate in cooperation transmission.If receiving node z _iCorrectly obtain transmitting node x _iData, then should jump transfer of data success of link; Otherwise should jump the data transmission fails of link, routing procedure finishes.

After current link executes above-mentioned relay collection foundation, transmission mode selection and three processes of transfer of data, judge the receiving node z of current link _iWhether be the destination node d of whole routed path, if not, the receiving node z of skip before link then will be worked as _iTransmitting node x as the down hop link _I+1, and again carry out above-mentioned three processes; If receiving node z _iBe the destination node d of this routed path, then this routed path transfer of data success, this routed path end of transmission.The present invention can in the situation that does not increase system emission power, improve the throughput of whole routed path by the throughput that improves every jumping link.

Below in conjunction with accompanying drawing, the embodiment of the cooperative routing method of the raising throughput of wireless networks that the present invention is proposed is described further.

Fig. 1 represents to improve the mode figure of the cooperative routing method of throughput of wireless networks.This cooperative routing method is at first set up the non-cooperation shortest path of multi-hop route according to non-cooperation shortest-path rout ing algorithms, comprise the multi-hop link in this path, transmitting node in each link is set up the candidate relay node set, by calculating the throughput under every kind of transmission mode, select the maximum of throughput, the transmission mode of adaptive determining link, and carry out transfer of data with link transmission pattern corresponding to maximum throughput.Particularly, source node s101 among Fig. 1 sends data to destination node d123, set up the non-cooperation of multi-hop by shortest-path rout ing algorithms and answer first formula shortest path route, node 102,107,109,111,113 and node 121 all to be the source node set up send the node that the shortest path route of data comprises to destination node.For in the multihop path each jump corresponding link all according to actual conditions select respectively single relay cooperative transmission pattern 108, directly transmission mode 112 or two relay cooperative transmission pattern 122 with transfer of data to receiving node.The below elaborates to three kinds of transmission meanss by Fig. 1.

For single relay cooperative transmission pattern 108 shown in Figure 1, node x _i102 transmitting nodes as current i jumping link through calculating the throughput under the current link different transmission mode, with the data transfer mode of single relay cooperative transmission pattern as current link, and select node 104 as via node r _i ^sAssist transmitting node x _i102 send data to the receiving node z of this jumping link _i107.At first, transmitting node x _i102 with power P ^MaxThe data that on/2 needs sent are broadcasted, data through the path 103 and 105 respectively by via node r _i ^s104 and receiving node z _i107 receive.And then via node r _i ^s104 decodings also detect the correctness of receive data, if this moment via node r _i ^s104 can decode correctly, then with power P ^Max/ 2 on time slot 106 with this data retransmission to receiving node z _i107; Otherwise abandon this packet.Finally, receiving node z _i107 receive transmitting node x _iData and the via node r of 102 broadcasting _i ^s104 data of transmitting, the correctness of decoding and judgement data.If can be correctly decoded initial data, then represent the transfer of data success of this jumping link; Otherwise the data transmission fails that represents this jumping link.

For direct transmission mode 112 shown in Figure 1, node x _j109 transmitting nodes as current j jumping link through calculating the throughput under the current link different transmission mode, select direct transmission mode as the transmission means of current link.At first, transmitting node x _j109 with transmitting power P ^MaxSend packet, the 110 received node z through the path _j111 receive.Then receiving node z _jThe correctness of 111 decodings and detection receive data.If receiving node z _j111 can be correctly decoded, this jumping link data transmission success then, otherwise the bust this of this jumping link data.

For two relay cooperative transmission patterns 122 shown in Figure 1, node x _k113 transmitting nodes as current k-hop link through calculating the throughput under the current link different transmission mode, are finally selected two relay cooperative transmission patterns as the transmission means of current link, and are selected via node And via node

Assist transmitting node x _k113 send data to the receiving node z of this jumping link _k121.At first, transmitting node x _k113 with power P ^Max/ 3 pairs of data that need to send are broadcasted, data respectively through the path 114,115 and 116 by via node

With receiving node z _k121 receive.And then via node

And via node

Decoding also detects whether can be correctly decoded the data that receive.If via node

Detect and to be correctly decoded the data that receive, then with power P ^Max/ 3 transmit these information through the path 119 to receiving node z _k121; If via node

Detect and to be correctly decoded the data that receive, then with power P ^Max/ 3 transmit these information through the path 120 to receiving node z _k121; If via node

Or

Be not correctly decoded transmitting node x _kThe data of 113 broadcasting then abandon misdata, do not carry out data retransmission.Finally, receiving node z _k121 decodings are from transmitting node x _k113, via node

Or

Data, then judge the correctness of receive data.If can be correctly decoded, then represent the transfer of data success of this jumping link; Otherwise the data transmission fails that represents this jumping link.

Fig. 2 represents the structure of the neighbors table that each node is safeguarded, the transmitting node of every jumping link is set up the candidate relay node set according to this neighbors table.In the cooperation Routing Protocol of the raising throughput of wireless networks that the present invention proposes, each node need to be safeguarded a neighbors table, and this neighbors table comprises three partial informations: the neighbors with the neighbors shown in the distance, 203 neighbors shown in the neighbors set, 202 shown in 201 is gathered.Suppose that Fig. 2 is transmitting node x _iThe neighbors table, the below jumps the transmitting node x of link with i _iBe example, the process that this node is made up the candidate relay node set further specifies.At first, present node x _iIn the neighbors table 201 row are retrieved, sought receiving node z _iThe row at place.Afterwards, selected receiving node z _iReceiving node z is namely sought in the position of corresponding 203 these row of being expert at _iNeighbors set.At last, judge successively in 201 row except receiving node z _iWhether neighbors in addition is at receiving node z _iNeighbors set in.If transmitting node x _iNeighbors equally at receiving node z _iNeighbors set in, just be inserted into candidate relay node set Ω _iIn, if transmitting node x _iNeighbors not at receiving node z _iNeighbors set in, then do not carry out insertion work, continue to judge next neighbors, until all neighborss are all judged finish.In addition, the range information that comprises of 202 among Fig. 2 row is the basis of carrying out relay selection.

Fig. 3 represents the process of the adaptively selected transmission mode of transmitting node of every jumping link.Jump link as example take i, at first, jump the transmitting node x of link for i _iAccording to neighbors table execution in step 302 shown in Figure 2, namely set up the candidate relay node set Ω of this jumping link _iSecondly, according to the throughput under the direct transmission of information and executing step 303 calculating that comprises in the neighbors table

Then, execution in step 304 is judged candidate relay node set Ω _iWhether be empty, if Ω _iBe sky, then execution in step 305 is with the throughput of the single relay cooperative transmission of maximum and the throughput under maximum two relay cooperative transmission With

Be set as 0; If candidate relay node set Ω _iBe not empty, then expression transmitting node this moment and receiving node have common neighbor node, then execution in step 306.In step 306, the throughput according to each node in the information calculations candidate relay node in the neighbors table during respectively as via node, and obtain throughput under the single relay cooperative pattern of maximum

The via node r corresponding with this value _iThen whether the nodes in execution in step 307 judgement candidate relay node set this moment is greater than 2, and candidate relay node number is less than 2 at this moment if judge, and then execution in step 308 is with the maximum throughput under two relay cooperative transmissions

Be set as 0; If this moment, candidate relay node number was more than or equal to 2, then expression this link this moment can select two relay cooperative transmission modes that data are transmitted, further execution in step 309 is calculated every pair of corresponding link throughput of via node, and selects the throughput under maximum two relay cooperative transmissions The via node r corresponding with this value _i ¹And r _i ²At this moment, current transmitting node x _iObtain throughput under the direct transmission mode by above step

Maximum throughput under single relay cooperative transmission pattern

With the maximum throughput under two relay cooperative transmission patterns

And then the maximum in three values of execution in step 310 selections is as the maximum throughput η of current link ^MaxContinue execution in step 311 and judge the maximum throughput η of current link ^MaxWhether equal the throughput under the direct transmission mode

If judge η ^MaxEqual Then execution in step 312 selects direct mode as the data transfer mode of current link; If judge η ^MaxBe not equal to η

Then execution in step 313 is judged the maximum throughput η of current link ^MaxWhether equal the throughput under maximum single relay cooperative transmission

If η ^MaxEqual

Then execution in step 314 is with the data transfer mode of single relay cooperative transmission mode as current link; If η ^MaxBe not equal to

Then represent η ^MaxEqual the maximum throughput under two relay cooperative transmission patterns

Further execution in step 315 is with the data transfer mode of two relay cooperative transmission modes as current link.By above step, the transmitting node of every jumping link is finished the selection course to current link data transmission means.

The transmission course of packet when Fig. 4 represents that link adopts single relay cooperative transmission or two relay cooperative transmission pattern.At first, from 401, the transmitting node x of this link _iExecution in step 402, i.e. broadcast data packets in first time slot.In step 402, if adopt single relay cooperative transmission pattern that data are transmitted, then transmitting node is with power P ^Max/ 2 pairs of transfer of data; If adopt two relay cooperative transmission patterns that data are transmitted, then transmitting node is with power P ^Max/ 3 pairs of transfer of data.Then, single relay cooperative node r of this link _i ^sOr two relay cooperative nodes

With

Execution in step 403, i.e. transmitting node x to receiving _iThe packet of broadcasting is decoded, and execution in step 404 judges whether successfully decoded.If the received signal to noise ratio of this packet of via node this moment is lower than the threshold value of setting, expression can't be correctly decoded this packet, and then execution in step 405 abandons packet; If this moment, received signal to noise ratio was higher than the threshold value of setting, then expression can be correctly decoded this packet, the via node that is correctly decoded follow execution in step 406 in the packet of second time slot transmitted power broadcasting decoder according to the rules to receiving node z _iIn step 406, if adopt single relay cooperative transmission pattern, then via node r _i ^sWith power P ^Max/ 2 pairs of data are transmitted; If adopt two relay cooperative transmission pattern, then via node r _i ^S1And r _i ^S2All with power P ^Max/ 3 pairs of data are transmitted.At last, receiving node execution in step 407, i.e. decoding data to receiving, execution in step 408 judges whether to be correctly decoded and to obtain initial data simultaneously.Obtain initial data if can be correctly decoded, this link data transmission success 410 then, this jumps link data end of transmission 412; Obtain initial data if can not be correctly decoded, then execution in step 409 abandons this packet, this link data bust this 411, DTD 412.

Specific embodiment

Embodiments of the invention are take the network of 200m * 200m of comprising 20 mobile nodes as example, and the maximum node transmitting power is 15dBm, path loss factor-alpha=4, and the channel between all nodes is independent identically distributed quasistatic Rayleigh fading channel.In conjunction with specific embodiments, the performance of the cooperative routing method of the raising throughput of wireless networks of checking the present invention design.

The specific works step of the cooperative routing method of the raising throughput of wireless networks that the present invention proposes is as follows:

Step 1: in network, select at random a pair of node respectively as source node s and destination node d, utilize the non-cooperation shortest path route of aim sequence distance vector routing protocol (DSDV) foundation from source node s to destination node d, and from source node s, with each node on the link successively as transmitting node, the candidate relay node set of setting up every link according to neighbors table and the routing table of transmitting node;

Step 2: the transmitting node x of every jumping link _iAccording to the candidate relay node set of setting up, the throughput under the throughput under the throughput under the direct mode on the calculating book bar link and all possible single relay cooperative transmission mode and the two relay cooperative transmissions successively, and therefrom relatively obtain the maximum link throughput.Then judge the maximum link throughput situation of this moment, and set up respectively the respective transmissions pattern according to actual conditions:

If the maximum throughput of ■ is the throughput value under the direct transmission mode, is direct mode with the transmission system setting under the current link then, transmitting node x _iWith P ^MaxThe transmitted power broadcasting of=15dBm=31.6228mW needs the packet of transmission;

If the maximum throughput of ■ is the throughput value under single relay node cooperation transmission mode, be the final via node r of current link with the corresponding trunk node selection of maximum throughput under single relay cooperative transmission of selecting to obtain then _i ^s, set simultaneously transmitting node x _iWith via node r _i ^sTransmitting power be P ^Max/ 2=15.8114mW.At first time slot transmitting node x _iTo via node r _i ^sWith receiving node z _iBroadcast data, simultaneously via node r _i ^sThe data that decoding receives.At second time slot, be correctly decoded the via node r of packet _i ^sThe data that decoding is obtained are sent to receiving node z _iIf receiving node is correctly decoded initial data, then think current link data transmission success.If receiving node can not be correctly decoded initial data, then think current link data bust this;

If the maximum throughput of ■ is the throughput value under two relay node cooperation transmission modes, then with the corresponding via node r of maximum throughput under two relay cooperative transmissions of selecting to obtain _i ¹And r _i ²Be chosen as the final via node of current link

With

Set simultaneously transmitting node x _i, via node

And via node

Transmitting power be P ^Max/ 3=10.5409mW.At first time slot, transmitting node x _iTo via node

With Broadcast data.Then, via node

With

The data that decoding receives.If via node

With

Can not be correctly decoded the data that receive, then abandon this data, no longer participate in follow-up transfer of data; If via node With

Can be correctly decoded the data that receive, then second this packet of time slot repeating to receiving node z _iAt last, receiving node z _iTo receiving transmitting node x _iThe packet or the via node that send

With

The packet of transmitting is decoded.If can be correctly decoded, then represent this link data transmission success; If can not obtain correct initial data, then represent this link data bust this.

Step 3: the receiving node z of current link _iAfter obtaining correct data, judge receiving node z _iWhether be destination node d.If so, then finish the transfer of data of this routed path; If not, then with this receiving node z _iTransmitting node x as the down hop respective links _I+1, proceed the down hop transfer of data.

Present embodiment is considered maximum transmission power, network node number and maximum translational speed to the impact of route Algorithm Performance, and carries out performance simulation according to following five kinds of different routing algorithms respectively:

1. the cooperation routing algorithm of the raising throughput of wireless networks that proposes of the present invention;

2. the DSDV routing algorithm of non-cooperation;

3. based on the routing algorithm of the single relay cooperative route transmission pattern under the shortest path Routing Protocol, namely the transmitting node in every jumping link selects single relay cooperative transmission pattern of throughput maximum that data are transmitted.In particular cases, if the candidate relay node set is empty, then adopt direct transmission mode that data are transmitted;

4. based on the routing algorithm of fixing two relay cooperative route transmission patterns of DSDV, namely the transmitting node in every jumping link selects two relay cooperative transmission patterns of throughput maximum that data are transmitted.In particular cases, if a node is only arranged in the candidate relay node set, then adopt single relay cooperative route transmission pattern to carry out transfer of data; If the candidate relay node set is empty, then adopt direct transmission mode that data are transmitted;

5. based on the routing algorithm of fixing three relay cooperative route transmission patterns of DSDV, namely the transmitting node in every jumping link selects three relay cooperative transmission patterns of throughput maximum that data are transmitted.In particular cases, if two nodes are only arranged in the candidate relay node set, then adopt two relay cooperative route transmission patterns to carry out transfer of data; If a node is only arranged in the candidate relay node set, then adopt single relay cooperative route transmission pattern to carry out transfer of data; If the candidate relay node set is empty, then adopt direct transmission mode that data are transmitted;

Fig. 5 represents that network throughput is along with different maximum transmission power P ^MaxChange curve, obtain respectively the throughput situation of change of above five kinds of routing algorithms under different maximum transmission power.As can be seen from Figure 5, the throughput that the routing algorithm that adopts DSDV shortest path Routing Protocol obtains during as the transmission means of whole piece link is minimum.The cooperation transmission pattern that adopts the fixed number via node adopts two relay cooperative transmission patterns to adopt single relaying or three relay cooperative transmission patterns can obtain larger throughput during as the transmission means of every jumping link.The network throughput performance of the cooperation routing algorithm of the raising throughput of wireless networks that the present invention proposes is better than other four kinds of routing algorithms.Simulation result shows that when maximum transmission power was 18dBm, the throughput performance of the cooperative routing method of the raising throughput of wireless networks that the present invention proposes had improved about 21.8% than DSDV.Because total transmitting power of cooperation routing algorithm is not more than the transmitting power of non-cooperation routing algorithm, so the lifting of throughput has demonstrated fully the advantage that collaboration diversity brings.

Fig. 6 represents that network throughput is along with the change curve of heterogeneous networks number of nodes.As can be seen from the figure, along with the increase of nodes number, adopt the network throughput under the DSDV shortest path Routing Protocol to fluctuate up and down at 1.3bit/s/Hz place, but during the employing cooperation transmission, network throughput increase along with the increase of network node number.The network throughput performance of the cooperation routing algorithm of the raising throughput of wireless networks that the present invention proposes is better than other four kinds of routing algorithms.Simulation result shows, when network node number is 30, improved throughput hoisting that the throughput performance of the cooperative routing method of throughput of wireless networks obtains than the transmission means under the DSDV agreement about 31.3%.

Fig. 7 represents that network throughput is with the change curve of the maximum translational speed of node.Along with node motion speed increases, the network throughput of various routing algorithms is on a declining curve, the cooperation route transmission method of the raising throughput of wireless networks that the present invention proposes still can obtain preferably network throughput for the transmission means under fixed relay cooperation transmission mode and the DSDV Routing Protocol.Simulation result shows, when the maximum translational speed of node is 25m/s, the throughput hoisting that the network throughput of the cooperative routing method of the raising throughput of wireless networks that the present invention proposes obtains than the transmission means under the DSDV agreement 22.7%.

More than describe the specific embodiment of the present invention in detail; but protection scope of the present invention is not limited to this; adopt the cooperation routing algorithm that similarly improves throughput of wireless networks; any person of ordinary skill in the field; without departing from the spirit and scope of the present invention; all can do a little change and improvement, but it all should belong to the protection range of claim of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claims.The present invention is directed to wireless communication field, comprise that the routing algorithm of wireless cooperation communication system all can adopt method of the present invention, retrained by claim of the present invention if adopt.

Claims (3)

1. cooperative routing method that improves throughput of wireless networks, it is characterized in that, in the basic enterprising step of advancing of the non-cooperation shortest path of multi-hop route by selection, the transfer of data that the mode of source node by multi-hop will need to send is to destination node, the stage by stage transmission three phases of the foundation of every jumping link experience candidate relay node set, transmission mode selection and packet, in the phase I, according to the non-cooperation multi-hop routed path of having set up, the transmitting node x of every jumping link _iSet up candidate relay node set Ω by the routing table and the neighbor node table that have established _iSecond stage, the transmitting node x of current link _iTravel through all transmission modes, calculate in these three kinds of Basic Transmission Unit of direct transmission, single relay cooperative transmission and two relay cooperative transmission and have the transmission mode of maximum link throughput as the final transmission mode of current link, and select node in the corresponding candidate relay node set as via node; In the phase III, transmitting node x _iParticipate in the transmitting power of the node of this link data transmission according to the link transmission pattern dynamic assignment of final selection, and carry out transfer of data, if the transmission mode of maximum link throughput is direct transmission, then this transmitting node x _iMode by direct transmission sends data to the receiving node z when the skip before link _iIf the transmission mode of maximum link throughput is cooperation transmission, this transmitting node x then _iAccording to result of calculation from candidate relay set Ω _iIn select corresponding via node and assist transmitting node x _iTo receiving node z _iTransmission information.

2. a kind of cooperative routing method that improves throughput of wireless networks as claimed in claim 1 is characterized in that, routing algorithm is made of direct transmission, single relay cooperative transmission and three kinds of basic link transmission units of two relay cooperative transmission; Source node s jumps transfer of data to destination node d by n, and wherein i jumps the transmitting node x of institute's respective links _iSelect direct transmission mode, single relay cooperative transmission pattern or two relay cooperative transmission pattern with the receiving node z of transfer of data to this jumping link _i, 1≤i≤n; Particularly, directly transmission mode is the transmitting node x of current link _iBy the mode that direct transfers with transfer of data to receiving node z _i, by (x _i, z _i) representing this link, the throughput of this link is designated as

Single relay cooperative transmission pattern is the transmitting node x of current link _iFrom candidate relay node set Ω _iNode of middle selection is as via node r _iAssist transmitting node x _iTransmit data to receiving node z _i, by (x _i, r _i, z _i) representing this link, the throughput of this link is designated as

The transmitting node x that two relay cooperative transmission patterns are current link _iFrom candidate relay node set Ω _iTwo nodes of middle selection are as via node r _i ¹And r _i ²Assist transmitting node x _iTransmit data to receiving node z _i, by (x _i, r _i ¹, r _i ², z _i) representing this link, the throughput of this link is designated as

3. a kind of cooperative routing method that improves throughput of wireless networks as claimed in claim 2 is characterized in that the realization of routing algorithm comprises following steps successively:

Step 1 is utilized the multi-hop shortest path route of non-cooperation shortest-path rout ing algorithms structure from source node s to destination node d in wireless network, each node in this routed path is set up also routing table and the neighbors table of real-time update self, jumps the transmitting node x of link as i=1 with seasonal source node s ₁

Step 2 i jumps the transmitting node x of link _iInquire about the neighbors table of self, acquisition can with transmitting node x _iCan jump with this again the receiving node z of link _iAll nodes that communicate, the set that these nodes form is the candidate relay node set Ω of this jumping link _i

Step 3 i jumps the transmitting node x of link _iTraversal candidate relay set Ω _iIn all nodes, calculate the throughput under the direct transmission mode of this jumping link

Throughput under all possible single relay transmission pattern And the throughput under two relay transmission patterns Concrete operations are as follows:

Step 3.1 i jumps the transmitting node x of link _iCalculate direct transmission link (x _i, z _i) link throughput

${\mathrm{\&eta;}}_{x_i,z_i}=\exp (-\frac{(2^{R_0}-1)N_0{d}_{x_i,z_i}^{\mathrm{\&alpha;}}}{P^{\max }})\&times;R_0$

Wherein, P ^MaxBe transmitting node x _iTransmitting power,

Transmitting node x for current link _iWith receiving node z _iBetween distance, α is the path loss factor, R ₀Be information transmission rate, N ₀Be noise; Further, transmitting node x _iDetect candidate relay set Ω _iWhether be empty, if empty, then set the maximum throughput of single relay cooperative transmission link

Maximum throughput with two relay cooperative links

Be zero, and execution in step 4, if be not empty, then execution in step 3.2;

Step 3.2 i jumps the transmitting node x of link _iTraversal candidate relay set Ω _iIn all via nodes as the situation of single relay cooperative transmission pattern, calculate single relay cooperative transmission link (x _i, r _i, z _i) corresponding link throughput

${\mathrm{\&eta;}}_{x_i,r_i,z_i}=(\exp (-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i}^{\mathrm{\&alpha;}}-g{d}_{r_i,z_i}^{\mathrm{\&alpha;}})-\exp (-g{d}_{x_i,r_i}^{\mathrm{\&alpha;}}-g{d}_{r_i,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}}))\&times;R_0$

Wherein,

Single relay cooperative transmission pattern lower node x _iAnd r _iTransmitting power equate to be

Be transmitting node x _iWith destination node z _iBetween distance,

Be transmitting node x _iWith via node r _iBetween distance,

Be via node r _iWith destination node z _iBetween distance, α is the path loss factor, R ₀Be information transmission rate, N ₀Be noise; Pass through formula Calculate the throughput of maximum single relay cooperative transmission link

While transmitting node x _iDetect candidate relay set Ω _iMiddle candidate relay node number if candidate relay node number is less than two, is then set Equal zero, and execution in step 4, otherwise, execution in step 3.3;

Step 3.3 i jumps the transmitting node x of link _iTravel through all candidate relay nodes that make up in twos as two relaying r _i ¹And r _i ²Cooperation transmission the time situation, calculate two relay cooperative transmission link (x _i, r _i ¹, r _i ², z _i) link throughput

${\mathrm{\&eta;}}_{x_i,r_i^1,r_i^2,z_i}=(\exp (-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_{i1}^1,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_2,z_i}^{\mathrm{\&alpha;}})$

$-\exp (-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_i^1,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_i^2,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}})$

$-\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_i^2,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_i^1,z_i}^{\mathrm{\&alpha;}})+\exp (-g{d}_{x_i,r_i^2}^{\mathrm{\&alpha;}}-g{d}_{r_i^2,z_i}^{\mathrm{\&alpha;}}$

$-g{d}_{x_i,r_i^1}^{\mathrm{\&alpha;}}-g{d}_{r_i^1,z_i}^{\mathrm{\&alpha;}}-g{d}_{x_i,z_i}^{\mathrm{\&alpha;}}\left)\right)\&times;R_0$

Wherein,

Two relay cooperative transmission pattern lower node x _i, r _i ¹And r _i ²Transmitting power equate to be

Be transmitting node x _iWith destination node z _iBetween distance,

Be transmitting node x _iWith via node r _i ^j,

Between distance,

Be via node r _i ^jWith destination node z _iBetween distance, α is the path loss factor, R ₀Be information transmission rate, N ₀Be noise; Utilize formula

Calculate the throughput of maximum two relay cooperative transmission links

The throughput of the more direct transmission link of step 4

The throughput of maximum single relay cooperative transmission link

Throughput with maximum two relay cooperative transmission links Size, maximum wherein is set as the maximum η of current link throughput ^MaxIf link throughput corresponding to link under the direct transmission mode

Maximum, then execution in step 5; If link throughput corresponding to link under single relay cooperative transmission pattern

Maximum, then execution in step 6; If link throughput corresponding to link under two relay cooperative transmission patterns

Maximum, then execution in step 7;

Step 5 is set current transmitting node x _iTransmitting power be maximum transmission power P ^Max, adopt direct mode to transfer data to receiving node z _i, and execution in step 8;

The current transmitting node x of step 6 _iForward packets to receiving node z by selected via node with single relay cooperative transmission pattern _i, specific operation process is as follows:

Step 6.1 is with the link maximum throughput

Corresponding candidate relay node r _iAs the single via node r that chooses _i ^s

Step 6.2 is with current transmitting node x _iWith via node r _i ^sTransmitting power all be set as half of maximum transmission power, i.e. P ^Max/ 2;

The current transmitting node x of step 6.3 _iAt first time slot with transmitting power P ^Max/ 2 broadcast data packets, via node r _i ^sWith receiving node z _iReceive the data that transmitting node sends;

Step 6.4 via node r _i ^sTo the decoding data that receives, if the received signal to noise ratio of signal, is then thought via node r this moment greater than a specific thresholding _i ^sCan correctly receive transmitting node x _iSend data, i.e. successfully decoded, then at the second time slot with transmitting power P ^Max/ 2 transmit transmitting node x _iData to receiving node z _i, and execution in step 8; If received signal to noise ratio less than specific threshold value, is then thought and is decoded unsuccessfully, abandon this packet, and execution in step 8;

The current transmitting node x of step 7 _iSelect two relay cooperative transmission patterns to forward packets to receiving node z _i, specific operation process is as follows:

The current transmitting node x of step 7.1 _iWill

Two corresponding candidate relay nodes

With

As two via nodes choosing

With

Step 7.2 couple current transmitting node x _iWith two via nodes With

Carry out power setting, the transmitted power of these three nodes all is set as 1/3rd of maximum transmission power, i.e. P ^Max/ 3;

The current transmitting node x of step 7.3 _iAt first time slot with transmitting power P ^Max/ 3 broadcast data packets, via node

With

And receiving node z _iReceive this data;

Step 7.4 via node

With

To the decoding data that receives, if via node

With

The received signal to noise ratio that detects is greater than a specific thresholding, then thinks via node this moment

With

Can correctly receive transmitting node x _iThe transmission data, i.e. successfully decoded is then at the second time slot via node

With

Respectively with transmitting power P ^Max/ 3 transmit from transmitting node x _iData to receiving node z _i, and execution in step 8; Otherwise think and decode unsuccessfully, abandon this packet, and execution in step 8;

Step 8 receiving node z _iTo the decoding data that receives, if receiving node z _iCorrectly received transmitting node x _iOr the via node r that selects under single relay cooperative transmission pattern _i ^sOr the via node of selecting under two relay cooperative transmission patterns

With

The signal of sending, then execution in step 9; Otherwise the route data bust this finishes this route data transmission;

Step 9 is judged receiving node z _iWhether be the destination node d of routed path, if not, then current i is jumped the receiving node z of link _iJump the transmitting node x of link as i+1 _I+1, and return execution in step 2; If receiving node z _iBe the destination node d of routed path, then the route transmission data are successful, finish the transmission course of this routed path.

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