CN103078795B - Improve the cooperative routing method of throughput of wireless networks - Google Patents

Abstract

The invention belongs to wireless communication field, be mainly used in wireless self-organization network.Under the prerequisite not increasing network energy consumption, by maximizing the network throughput of every hop link, the throughput performance of the whole routed path of effective lifting, for reaching aforementioned object, the technical scheme that the present invention takes is, improve the cooperative routing method of throughput of wireless networks, source node sends data to destination node by multi-hop, first the transmitting node of every hop link sets up non-cooperating Shortest path routing, and sets up candidate relay node set by the routing table that established and neighbor node table; Then calculate the link throughput under directly transmission, single relay cooperative transmission and two relay cooperative transmission, transmission mode corresponding to adaptively selected maximum throughput is as the transmission means of this hop link; The transmission means dynamic conditioning power that last basis is chosen is gone forward side by side data packet transmission, until the transfer of data of source node is to destination 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 being applied to wireless self-networking, specifically, relate to the adaptive cooperation method for routing improving wireless self-organization network throughput.

Background technology

Along with the development of wireless communication technology, Mobile data and information service increase in a large number.Especially along with intelligent terminal and the extensive of multiple Mobile solution are popularized, the demand of people to wireless data service increases fast, therefore has higher requirement to wireless network performance indexs such as network throughputs.But on the one hand, in the mobile communication of reality, mobile terminal usually works in architecture ensemble or other geographical environment complicated and changeable, the signal that complicated geomorphological features makes receiving terminal receive generally can suffer the impact such as multipath fading, shadow fading.This decline can make Received signal strength serious distortion and distortion, reduces signal power, causes the communication system error rate to raise.On the other hand, wireless network bandwidth is much lower relative to wire message way.Along with developing rapidly of mobile Internet, radio network information flow increases rapidly, and make wireless network bandwidth not enough, bandwidth resources are more rare, and these all define very large obstruction to the raising of throughput of wireless networks performance.

In the wireless network, Design of Routing Protocol is very important, and wherein Shortest path routing agreement is a kind of common routing protocol in 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 agreement can be divided into two kinds, is respectively on-demand routing protocol and proactive routing protocol.Specifically, on-demand routing protocol is also referred to as Reactive routing protocols, and this quasi-protocol does not generate route before the request is received, and when network sends transmission request, just starts to search for the route set up from source node to destination node.Therefore, the routing iinformation of system is set up as required, and it only reflects a part for whole network topology information.On-demand routing generally comprises route discovery and two stages of route maintenance, and this agreement comprises wireless self-networking plan range vector Routing Protocol (AODV), dynamic source routing protocol (DSR), temporally ordered routing algorithm (TORA) etc. as required.And for proactive routing protocol, also known as Table Driven agreement, each node maintenance routing table, is recorded to the routing iinformation of each node.The grouping of node periodic broadcast, exchanging routing information each other between node.When network topology changes, node broadcasts routing update is divided into groups, and this updating message is spread all over whole network, and node upgrades the routing table of oneself according to upgrading grouping, thus obtains up-to-date network topological information.Therefore, source node, once need to send message, accurately can obtain the route arriving destination node immediately.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, cooperative communication technology can be adopted to improve the quality of Received signal strength.In wireless cooperative network, mobile terminal can select other is in idle condition in current time slots one or more mobile terminals to assist transmission information, that this mobile terminal not only make use of oneself in the process of transmission information but also the space channel that make use of cooperation mobile terminal, by sharing antenna each other, obtain diversity gain.Receive at receiving terminal the multiple copies carrying identical information that different channels transmits, recover original signal by certain signal processing technology.Because the transmission characteristic of multiple channel is different, the signal copy received has the fading characteristic of independence, therefore the impact of decline greatly can be reduced when not increasing system resource, expand the coverage of wireless network, improve transmission reliability, reduce transmitting power, thus improve wireless network performance.

Further, cooperative diversity technique and Route Selection can be combined, design the routing algorithm based on collaboration communication, namely cooperate routing algorithm.At present, the research for cooperation routing algorithm roughly can be divided into routing algorithm two class of Energy Efficient and peak optimizating network service quality (QoS).Specifically, for the routing algorithm of Energy Efficient, main thought sets up cooperation route in the wireless network according to certain rule, makes the power of system consumption minimum; The routing algorithm of optimization QoS then reaches the object of optimized communication system QoS by setting up cooperation route.Along with in network to QoS be strict with business as the appearance such as real-time multimedia traffic, the networking telephone, need mobile wireless network that corresponding QoS can be provided to ensure, therefore design optimization QoS routing algorithm is significant.But the features such as the mobility of mobile wireless network node, the finiteness of network bandwidth resources, the dynamic change of network topology structure, the computing capability of mobile node and memory capacity is lower, energy constraint, define challenge to the cooperation Design of Routing Algorithm of optimization QoS.Especially due to the mobility of network node, network topology constantly changes, and the via node before participating in cooperating may leave collaboration communication scope, thus causes synergistic link to lose efficacy.Cooperation route continue in selecting node time, need by real-time channel conditions select suitable via node to participate in cooperation.

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 improving 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: an enterprising step Route Selection of advancing on the basis of multi-hop non-cooperating Shortest path routing, source node will need the transfer of data sent to destination node by the mode of multi-hop, the three phases of transmission stage by stage of every hop link experience candidate relay node set foundation, transmission mode selection and packet, in the first stage, according to the non-cooperating multihop routing path set up, the transmitting node x of every hop link _icandidate relay node set omega is set up by the routing table that established and neighbor node table _i; Second stage, the transmitting node x of current ink _itravel through all transmission modes, calculate the final transmission mode of transmission mode as current ink in these three kinds of Basic Transmission Unit of direct transmission, single relay cooperative transmission and two relay cooperative transmission with maximum link throughput, and select node in 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 transfer according to the final link transmission pattern dynamic assignment selected, and carry out transfer of data, if the transmission mode of maximum link throughput is directly transmission, then this transmitting node x _ithe receiving node z of current hop link is sent data to by the mode directly transmitted _i; If the transmission mode of maximum link throughput is cooperation transmission, then this transmitting node x _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 by directly transmission, single relay cooperative transmission and two relay cooperative transmission three kinds of basic link transmission units are formed; Source node s is jumped by n and sends data to destination node d, and wherein i-th (1≤i≤n) jumps the transmitting node x of corresponding link _idirect transmission mode, single relay cooperative transmission pattern or two relay cooperative transmission pattern is selected to send data to the receiving node z of this hop link _i; Specifically, direct transmission mode is the transmitting node x of current ink _ireceiving node z is sent data to by the mode direct transferred _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 ink _ifrom candidate relay node set omega _imiddle selection node 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 two relay cooperative transmission pattern is the transmitting node x of current ink _ifrom candidate relay node set omega _imiddle selection two nodes 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 utilizes the multi-hop Shortest path routing of non-cooperating shortest-path rout ing algorithms structure from source node s to destination node d in the wireless network, each node in this routed path is set up and the routing table of real-time update self and neighbors table, with the transmitting node x of seasonal source node s as the i-th=1 hop link ₁;

The transmitting node x of step 2 i-th hop link _iinquire about the neighbors table of self, acquisition can with transmitting node x _iagain can with the receiving node z of this hop link _icarry out all nodes communicated, the set that these nodes form is the candidate relay node set omega of this hop link _i;

The transmitting node x of step 3 i-th hop link _itraversal candidate relay set Ω _iin all nodes, calculate the throughput under the direct transmission mode of this hop link throughput under all possible single relay transmission pattern and the throughput under two relay transmission pattern concrete operations are as follows:

The transmitting node x of step 3.1 i-th hop 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 ^maxfor transmitting node x _itransmitting power, for the transmitting node x of current ink _iwith receiving node z _ibetween distance, α is path-loss factor, R ₀for information transmission rate, N ₀for noise; Further, transmitting node x _idetect candidate relay set Ω _iwhether be empty, if it is empty, then set the maximum throughput of single relay cooperative transmission link with the maximum throughput of two relay cooperative link be zero, and perform step 4, if not empty, then perform step 3.2;

The transmitting node x of step 3.2 i-th hop 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 to be equally for transmitting node x _iwith destination node z _ibetween distance, for transmitting node x _iwith via node r _ibetween distance, for via node r _iwith destination node z _ibetween distance, α is path-loss factor, R ₀for information transmission rate, N ₀for noise; Pass through formula calculate the throughput of maximum single relay cooperative transmission link transmitting node x simultaneously _idetect candidate relay set Ω _imiddle candidate relay node number, if candidate relay node number is less than two, then sets equal zero, and perform step 4, otherwise, perform step 3.3;

The transmitting node x of step 3.3 i-th hop link _itravel through the candidate relay node of all combination of two as two relaying r _i ¹and r _i ²cooperation transmission time situation, calculate two relay cooperative transmission link (x _i, r _i ¹, r _i ², z _i) link throughput

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

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

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

$-g{d}_{x_i,r_i^1}^{\mathrm{\α}}-g{d}_{r_i^1,z_i}^{\mathrm{\α}}-g{d}_{x_i,z_i}^{\mathrm{\α}}\left)\right)\×R_0$

Wherein, two relay cooperative transmission pattern lower node x _i, r _i ¹and r _i ²transmitting power to be equally for transmitting node x _iwith destination node z _ibetween distance, for transmitting node x _iwith via node r _i ^j, between distance, for via node r _i ^jwith destination node z _ibetween distance, α is path-loss factor, R ₀for information transmission rate, N ₀for noise; Utilize formula calculate the throughput of maximum pair of relay cooperative transmission link

The throughput of the more direct transmission link of step 4 the throughput of maximum single relay cooperative transmission link with the throughput of maximum pair of relay cooperative transmission link size, maximum is wherein set as the maximum η of current ink throughput ^max; If the link throughput that the link directly under transmission mode is corresponding maximum, then perform step 5; If the link throughput that the link under single relay cooperative transmission pattern is corresponding maximum, then perform step 6; If the link throughput that the link under two relay cooperative transmission pattern is corresponding maximum, then perform step 7;

Step 5 sets current transmitting node x _itransmitting power be maximum transmission power P ^max, adopt direct mode to transfer data to receiving node z _i, and perform step 8;

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

Step 6.1 is by link maximum throughput corresponding candidate relay node r _ias the single via node r chosen _i ^s;

Step 6.2 is by current transmitting node x _iwith via node r _i ^stransmitting power be all set as the 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 received, if the received signal to noise ratio of signal is greater than a specific thresholding, then think now via node r _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 forward transmitting node x _idata to receiving node z _i, and perform step 8; If received signal to noise ratio is less than specific threshold value, then thinks and decode unsuccessfully, abandon this packet, and perform step 8;

The current transmitting node x of step 7 _itwo relay cooperative transmission pattern is selected 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 node with as two via nodes chosen with

Step 7.2 is to current transmitting node x _iwith two via nodes with carry out power setting, the transmitted power of these three nodes is all 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 received, if via node with the received signal to noise ratio detected is greater than a specific thresholding, then think now via node with can correctly receive transmitting node x _itransmission data, i.e. successfully decoded, then at the second time slot via node with respectively with transmitting power P ^max/ 3 forward from transmitting node x _idata to receiving node z _i, and perform step 8; Otherwise think and decode unsuccessfully, abandon this packet, and perform step 8;

Step 8 receiving node z _ito the decoding data received, if receiving node z _icorrectly have received transmitting node x _ior the via node r selected under single relay cooperative transmission pattern _i ^sor the via node selected under two relay cooperative transmission pattern with the signal sent, then perform step 9; Otherwise route data bust this, terminates the transmission of this route data;

Step 9 judges receiving node z _ibe whether the destination node d of routed path, if not, then by the receiving node z of current i-th hop link _ias the transmitting node x of the i-th+1 hop link _i+1, and return execution step 2; If receiving node z _ifor the destination node d of routed path, then route transmission data success, terminates the transmitting procedure of this routed path.

Technical characterstic of the present invention and effect as follows: the cooperative routing method of 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 not increasing system power dissipation.Specifically, the first, this cooperation route transmission method can the situation of change of sensing network topology in time, the wireless network that flexible adaptation topological structure constantly changes; The second, the node in route, according to the adaptive knot modification transmitting power of own situation, avoids consuming excessively of system capacity; 3rd, pass through comprehensively to select and compare in every hop link of adaptive cooperation route, select the link setting up throughput the best to carry out information transmission, effectively improve network throughput.

Accompanying drawing explanation

Fig. 1 is the mode figure of the cooperative routing method improving 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 the change curve of throughput with maximum transmission power.

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

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

Embodiment

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

Cooperative routing method designed by the present invention, under the condition not increasing system power dissipation, can significantly promote the throughput performance of wireless network.In the invention, using link throughput as the foundation 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 pattern, the maximum transmission mode of throughput is selected to carry out transfer of data, make the every hop link in the final route set up all have maximum throughput, thus promote the throughput performance of whole routed path.Due in cooperation transmission link, transmitting node and via node all need to send packet, in order to the consumption of control system energy, make total transmitting power of often jumping synergistic link be not more than total transmitting power of direct transmission link.Therefore, when adopting synergistic link transmission, to reset the transmitting power of link interior joint, thus avoiding consuming excessively of nodes energy.

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

First stage: the foundation of candidate relay node set.Specifically, first non-cooperating shortest-path rout ing algorithms is utilized to build multi-hop Shortest path routing from source node s to destination node d, all nodes on this routed path all need maintenance routing table and a neighbors table, when network topology structure changes, all nodes in this path upgrade in time respective routing table and neighbors table, the renewal of broadcast containing latest network information simultaneously divide into groups, and the renewal that each node receives the transmission of other node can upgrade and safeguard oneself routing table and neighbors table in time according to grouping information after dividing into groups.Further, the transmitting node x that on this Shortest path routing, each is jumped _iinquire about the neighbors table of self, according to this neighbors table obtain can with transmitting node x _iagain can with the receiving node z of this hop link _icarry out all nodes communicated, these nodes form the candidate relay node set omega of this hop link _i, every hop link carries out follow-up transmission mode selection based on this set of relay nodes.

Second stage: the selection of transmission mode, comprises and calculates link throughput under various transmission mode and link transmission pattern is determined in selection.Specifically, the transmitting node x in first current hop link _iutilize formula

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

Calculate from transmitting node x _ito receiving node z _ithe throughput of direct transmission link transmitting node x in every hop link _itraversal search candidate relay set Ω _iin all via nodes, utilize formula

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

Calculate the link throughput of single relay transmission pattern successively and compare and obtain maximum single repeated link throughput transmitting node x in every hop link _itraversal search candidate relay set Ω _iin all via nodes, utilize formula

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

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

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

$-g{d}_{x_i,r_i^1}^{\mathrm{\α}}-g{d}_{r_i^1,z_i}^{\mathrm{\α}}-g{d}_{x_i,z_i}^{\mathrm{\α}}\left)\right)\×R_0$

Calculate the link throughput of the two relay transmission patterns under every two via nodes combination successively and compare and obtain maximum pair of repeated link throughput then, the transmitting node x of every hop link _iaccording to the link throughput under the direct transmission calculated maximum single repeated link throughput with maximum single repeated link throughput relatively obtain the maximum throughput η of this hop link ^max, and select maximum throughput η ^maxcorresponding transmission mode is as the final data transmission mode of current ink.If select direct transmission mode, then employing non-cooperating transmission mode is carried out transfer of data by this link; If select single relay cooperative transmission pattern, then by maximum throughput corresponding via node elects the via node r assisting transmitting node transmission data as _i ^s; If select two relay cooperative transmission pattern, then by maximum throughput a pair corresponding via node elects the via node of assisting transmitting node transmission data as with

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

If current ink selects direct transmission mode, setting transmitting node x _itransmitting power be maximum transmission power P ^max, transmitting node x _iaccording to power P ^maxbroadcast data packets, if receiving node z _ireceive correct information, then the transfer of data success of this hop link; Otherwise the data transmission fails of this hop link, routing procedure terminates.

If current ink selects single node cooperation transmission pattern, first set the transmitting node x of this link _iwith the via node r chosen _i ^stransmitting power be the 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 chosen _i ^scan correctly receive transmitting node x _ithe data of broadcast, then according to the receiving node z of the power set to current ink _iforwarding data divides into groups, otherwise via node r _i ^sdo not participate in cooperation transmission.If receiving node z _ican correctly recover transmitting node x _idata, then this hop link transfer of data success; Otherwise the data transmission fails of this hop link, routing procedure terminates.

If current ink selects binode cooperation transmission pattern, first set the transmitting node x of this link _iwith the via node chosen 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 broadcast, then will be correctly decoded the receiving node z of data retransmission to current ink according to the power of setting _i, cannot correctly receive transmitting node x _ithe via node of the packet of broadcast does not then participate in cooperation transmission.If receiving node z _icorrectly obtain transmitting node x _idata, then this hop link transfer of data success; Otherwise the data transmission fails of this hop link, routing procedure terminates.

Current ink judges the receiving node z of current ink after executing the foundation of above-mentioned relay collection, transmission mode selection and transfer of data three processes _ibe whether the destination node d of whole routed path, if not, then by the receiving node z of current hop link _ias the transmitting node x of down hop link _i+1, and again perform above-mentioned three processes; If receiving node z _ifor 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 when not increasing system emission power, can improve the throughput of whole routed path by the throughput improving every hop 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 proposes is described further.

Fig. 1 represents the mode figure of the cooperative routing method improving throughput of wireless networks.First this cooperative routing method sets up multi-hop non-cooperating Shortest path routing according to non-cooperating shortest-path rout ing algorithms, multi-hop link is comprised in this path, transmitting node in each link sets up candidate relay node set, by calculating the throughput under often kind of transmission mode, select the maximum of throughput, the transmission mode of adaptive determining link, and carry out transfer of data with the link transmission pattern that maximum throughput is corresponding.Specifically, source node s101 in Fig. 1 sends data to destination node d123, set up multi-hop non-cooperating proactive Shortest path routing by shortest-path rout ing algorithms, node 102,107,109,111,113 and node 121 are all the nodes that the source node set up comprises to the Shortest path routing that destination node sends data.Jumping corresponding link for each in multihop path all selects single relay cooperative transmission pattern 108, directly transmission mode 112 or two relay cooperative transmission pattern 122 to send data to receiving node according to actual conditions respectively.By Fig. 1, three kinds of transmission meanss are elaborated below.

For the single relay cooperative transmission pattern 108 shown in Fig. 1, node x _i102 as the transmitting node of current i-th hop link, and the throughput under calculating current ink different transmission mode, using the data transfer mode of single relay cooperative transmission pattern as current ink, and selects node 104 as via node r _i ^sassist transmitting node x _ithe 102 receiving node z sending data to this hop link _i107.First, transmitting node x _i102 with power P ^maxon/2 to need send data broadcast, data through path 103 and 105 respectively by via node r _i ^s104 and receiving node z _i107 receive.And then via node r _i ^s104 decode and detect receives the correctness of data, if now via node r _i ^s104 can decode correctly, then with power P ^max/ 2 on time slot 106 by this data retransmission to receiving node z _i107; Otherwise abandon this packet.Finally, receiving node z _i107 receive transmitting node x _ithe data of 102 broadcast and via node r _i ^s104 data forwarded, decode and judge the correctness of data.If initial data can be correctly decoded, then represent the transfer of data success of this hop link; Otherwise represent the data transmission fails of this hop link.

For the direct transmission mode 112 shown in Fig. 1, node x _j109 as the transmitting node of current jth hop link, and the throughput under calculating current ink different transmission mode, selects direct transmission mode as the transmission means of current ink.First, transmitting node x _j109 with transmitting power P ^maxsend packet, be received node z through path 110 _j111 receive.Then receiving node z _j111 decode and detect the correctness receiving data.If receiving node z _j111 can be correctly decoded, then this hop link transfer of data success, otherwise this hop link data transmission fails.

For the two relay cooperative transmission patterns 122 shown in Fig. 1, node x _k113 as the transmitting node of current kth hop link, the throughput under calculating current ink different transmission mode, finally selects two relay cooperative transmission pattern as the transmission means of current ink, and selects via node and via node assist transmitting node x _kthe 113 receiving node z sending data to this hop link _k121.First, transmitting node x _k113 with power P ^max/ 3 to need send data broadcast, data respectively through path 114,115 and 116 by via node with receiving node z _k121 receive.And then via node and via node decode and detect and whether can be correctly decoded the data received.If via node the data that can be correctly decoded and receive detected, then with power P ^max/ 3 forward this information through path 119 to receiving node z _k121; If via node the data that can be correctly decoded and receive detected, then with power P ^max/ 3 forward this information through path 120 to receiving node z _k121; If via node or be not correctly decoded transmitting node x _kthe data of 113 broadcast, 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 to receive the correctness of data.If can be correctly decoded, then represent the transfer of data success of this hop link; Otherwise represent the data transmission fails of this hop link.

Fig. 2 represents the structure of the neighbors table that each node is safeguarded, the transmitting node of every hop link sets up 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 needs maintenance neighbors table, and this neighbors table comprises three partial informations: shown in the neighbors set, 202 shown in 201 with the neighbors set of the neighbors shown in the distance, 203 of neighbors.Suppose that Fig. 2 is transmitting node x _ineighbors table, below with the transmitting node x of the i-th hop link _ifor example, the process this node being built to candidate relay node set is further described.First, present node x _i201 row in neighbors table are retrieved, finds receiving node z _ithe row at place.Afterwards, selected receiving node z _ithe position of 203 corresponding these row of being expert at, namely find receiving node z _ineighbors set.Finally, judge successively in 201 row except receiving node z _iwhether neighbors is in addition at receiving node z _ineighbors set in.If transmitting node x _ineighbors equally at receiving node z _ineighbors set in, be just inserted into candidate relay node set omega _iin, if transmitting node x _ineighbors not at receiving node z _ineighbors set in, then do not carry out insertion work, continue judge next neighbors, until all judged all neighborss.In addition, it is the basis of carrying out relay selection that 202 in Fig. 2 arranges the range information comprised.

Fig. 3 represents the process of the adaptively selected transmission mode of the transmitting node of every hop link.For the i-th hop link, first, for the transmitting node x of the i-th hop link _ineighbors table according to Fig. 2 performs step 302, namely sets up the candidate relay node set omega of this hop link _i.Secondly, the throughput under directly transmission is calculated according to the information and executing step 303 comprised in neighbors table then, perform step 304 and judge candidate relay node set omega _iwhether be empty, if Ω _ifor sky, then perform step 305 by the throughput under the throughput of maximum single relay cooperative transmission and maximum pair of relay cooperative transmission with be set as 0; If candidate relay node set omega _ibe not empty, then represent that now transmitting node and receiving node have common neighbor node, then perform step 306.Within step 306, according to each node in the information calculated candidate via node in neighbors table respectively as throughput during via node, and obtain the throughput under maximum list relay cooperative pattern the via node r corresponding with this value _i.Then perform step 307 and judge whether the nodes in now candidate relay node set is greater than 2, if judge that now candidate relay node number is less than 2, then perform step 308 by the maximum throughput under two relay cooperative transmission be set as 0; If now candidate relay node number is more than or equal to 2, then represent that now this link can select two relay cooperative transmission mode to transmit data, further execution step 309 calculates the link throughput corresponding to often pair 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 ².Now, current transmitting node x _ithe throughput under direct transmission mode is obtained by above step maximum throughput under single relay cooperative transmission pattern with the maximum throughput under two relay cooperative transmission pattern and then execution step 310 selects the maximum in three values as the maximum throughput η of current ink ^max.Continue to perform the maximum throughput η that step 311 judges current ink ^maxwhether equal the throughput under direct transmission mode if judge η ^maxequal then performing step 312 selects direct mode as the data transfer mode of current ink; If judge η ^maxbe not equal to η then perform the maximum throughput η that step 313 judges current ink ^maxwhether equal the throughput under maximum single relay cooperative transmission if η ^maxequal then perform step 314 using the data transfer mode of single relay cooperative transmission mode as current ink; If η ^maxbe not equal to then represent η ^maxequal the maximum throughput under two relay cooperative transmission pattern further execution step 315 is using the data transfer mode of two relay cooperative transmission mode as current ink.By above step, the transmitting node of every hop link completes the selection course to current ink data transfer mode.

The transmitting procedure of packet when Fig. 4 represents that link adopts single relay cooperative transmission or two relay cooperative transmission pattern.First, start from 401, the transmitting node x of this link _iperform step 402, i.e. broadcast data packets in first time slot.In step 402, if adopt single relay cooperative transmission pattern to transmit data, then transmitting node is with power P ^max/ 2 pairs of transfer of data; If adopt two relay cooperative transmission pattern to transmit data, 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 node with perform step 403, namely to the transmitting node x received _ithe packet of broadcast is decoded, and performs step 404 and judge whether successfully decoded.If the received signal to noise ratio of now this packet of via node is lower than the threshold value of setting, expression cannot be correctly decoded this packet, then perform step 405 and abandon packet; If now received signal to noise ratio is higher than the threshold value of setting, then represents and can be correctly decoded this packet, the via node be correctly decoded then perform step 406 at second time slot according to the packet of transmitted power broadcasting decoder of regulation to receiving node z _i.In a 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.Finally, receiving node performs step 407, namely to the decoding data received, performs step 408 simultaneously and judges whether be correctly decoded and obtain initial data.If can be correctly decoded and obtain initial data, then this link data transfer success 410, this hop link DTD 412; If can not be correctly decoded and obtain initial data, then perform step 409 and abandon this packet, this link data transfer failure 411, DTD 412.

Specific embodiment

Embodiments of the invention are to comprise the network of the 200m × 200m of 20 mobile nodes, and maximum node transmitting power is 15dBm, path-loss factor α=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 the present invention's design is verified.

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: Stochastic choice a pair node is respectively as source node s and destination node d in a network, utilize the non-cooperating Shortest path routing of aim sequence distance vector routing protocol (DSDV) foundation from source node s to destination node d, and from source node s, using each node on link successively as transmitting node, set up the candidate relay node set of every bar link according to the neighbors table of transmitting node and routing table;

Step 2: the transmitting node x of every hop link _iaccording to the candidate relay node set of setting up, calculate the throughput under the throughput under the direct mode on this link and the throughput under all possible single relay cooperative transmission mode and two relay cooperative transmission successively, and therefrom compare and obtain maximum link throughput.Then judge maximum link throughput situation now, and set up respective transmissions pattern respectively according to actual conditions:

If the maximum throughput of ■ is the throughput value under direct transmission mode, be then direct mode by the transmission system setting under current ink, transmitting node x _iwith P ^maxthe transmitted power broadcast of=15dBm=31.6228mW needs the packet sent;

If the maximum throughput of ■ is the throughput value under single relay node cooperation transmission mode, be then the final via node r of current ink by the trunk node selection corresponding to the maximum throughput under the single relay cooperative transmission selecting to obtain _i ^s, set transmitting node x simultaneously _iwith via node r _i ^stransmitting power be P ^max/ 2=15.8114mW.At first slot transmission 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 ^sby decoding, the data obtained are sent to receiving node z _i.If receiving node is correctly decoded initial data, then think that current ink transfer of data is successful.If receiving node can not be correctly decoded initial data, then think current ink data transmission fails;

If the maximum throughput of ■ is the throughput value under two relay node cooperation transmission mode, then by the via node r corresponding to the maximum throughput under two relay cooperative transmissions of selecting to obtain _i ¹and r _i ²be chosen as the final via node of current ink with set transmitting node x simultaneously _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 the data received can not be correctly decoded, then abandon this data, no longer participate in follow-up transfer of data; If via node with the data received can be correctly decoded, then second this packet of time slot repeating to receiving node z _i.Finally, receiving node z _ito receiving transmitting node x _ithe packet sent or via node with the packet forwarded is decoded.If can be correctly decoded, then represent this link data transfer success; If correct initial data can not be obtained, then represent this link data transfer failure.

Step 3: the receiving node z of current ink _iafter obtaining correct data, judge receiving node z _inode d whether.If so, then the transfer of data of this routed path is terminated; If not, then by this receiving node z _ias the transmitting node x of down hop respective links _i+1, proceed down hop transfer of data.

The present embodiment considers that maximum transmission power, network node number and maximum translational speed are to the performance impact of routing algorithm, 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 of the present invention's proposition;

2. the DSDV routing algorithm of non-cooperating;

3., based on the routing algorithm of the single relay cooperative route transmission pattern under Shortest path routing agreement, the transmitting node namely in every hop link selects the maximum single relay cooperative transmission pattern of throughput to transmit data.In particular cases, if candidate relay node set is empty, then direct transmission mode is adopted to transmit data;

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

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

Fig. 5 represents that network throughput is along with different maximum transmission power P ^maxchange curve, obtain the throughput situation of change of above five kinds of routing algorithms under different maximum transmission power respectively.As can be seen from Figure 5, adopt the throughput obtained during the transmission means of the routing algorithm of DSDV Shortest path routing agreement as whole piece link minimum.When adopting the transmission means of the cooperation transmission pattern of fixed number via node as every hop link, two relay cooperative transmission patterns are adopted comparatively to adopt single relaying or three relay cooperative transmission patterns can obtain larger throughput.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, and when maximum transmission power is 18dBm, the throughput performance of the cooperative routing method of the raising throughput of wireless networks that the present invention proposes improves about 21.8% than DSDV.Total transmitting power due to the routing algorithm that cooperates is not more than the transmitting power of non-cooperative routing algorithm, and therefore the lifting of throughput has fully demonstrated the advantage that collaboration diversity brings.

Fig. 6 represents the change curve of network throughput along with heterogeneous networks number of nodes.As can be seen from the figure, along with the increase of nodes number, adopt the network throughput under DSDV Shortest path routing agreement to fluctuate up and down at 1.3bit/s/Hz place, but when adopting 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, and throughput hoisting that the throughput performance of cooperative routing method improving throughput of wireless networks obtains than the transmission means under DSDV agreement about 31.3%.

Fig. 7 represents the change curve of network throughput with the maximum translational speed of node.Along with node motion speed increases, the network throughput of various routing algorithm is on a declining curve, the cooperation route transmission method of the raising throughput of wireless networks that the present invention proposes, for the transmission means under fixed relay cooperation transmission mode and DSDV Routing Protocol, still can obtain good network throughput.Simulation result shows, when the maximum translational speed of node is 25m/s, and throughput hoisting that the network throughput of cooperative routing method of the raising throughput of wireless networks that the present invention proposes obtains than the transmission means under 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 thereto; adopt the cooperation routing algorithm of similar raising 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, the routing algorithm comprising wireless co-operative communication system all can adopt method of the present invention, according to then all retraining by claim of the present invention.

Claims (2)

1. one kind is improved the cooperative routing method of throughput of wireless networks, it is characterized in that, an enterprising step Route Selection of advancing on the basis of multi-hop non-cooperating Shortest path routing, source node will need the transfer of data sent to destination node by the mode of multi-hop, the three phases of transmission stage by stage of every hop link experience candidate relay node set foundation, transmission mode selection and packet, in the first stage, according to the non-cooperating multihop routing path set up, the transmitting node x of current ink _icandidate relay node set omega is set up by the routing table that established and neighbor node table _i; Second stage, transmission mode in routing algorithm is by directly transmission, single relay cooperative transmission and two relay cooperative transmission three kinds of basic link transmission units are formed, source node s is jumped by n and sends data to destination node d, the transmitting node x of the current ink wherein corresponding to the i-th jumping _idirect transmission mode, single relay cooperative transmission pattern or two relay cooperative transmission pattern is selected to send data to the receiving node z of this hop link _i, 1≤i≤n; Second stage comprises: the transmitting node x of current ink _itravel through all transmission modes, calculate the final transmission mode of transmission mode as current ink in these three kinds of Basic Transmission Unit of direct transmission, single relay cooperative transmission and two relay cooperative transmission with maximum link throughput, and select node in corresponding candidate relay node set as via node; Wherein, direct transmission mode is the transmitting node x of current ink _ireceiving node z is sent data to by the mode direct transferred _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 ink _ifrom candidate relay node set omega _imiddle selection node 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 two relay cooperative transmission pattern is the transmitting node x of current ink _ifrom candidate relay node set omega _imiddle selection two nodes 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 in the phase III, the transmitting node x of current ink _iparticipate in the transmitting power of the node of this link data transfer according to the final link transmission pattern dynamic assignment selected, and carry out transfer of data, if the transmission mode of maximum link throughput is directly transmission, then the transmitting node x of current ink _ithe receiving node z of current hop link is sent data to by the mode directly transmitted _i; If the transmission mode of maximum link throughput is cooperation transmission, then the transmitting node x of current ink _iaccording to result of calculation from candidate relay set Ω _iin select corresponding via node and assist the transmitting node x of current ink _ito receiving node z _itransmission information.

2. a kind of cooperative routing method improving throughput of wireless networks as claimed in claim 1, it is characterized in that, the realization of routing algorithm comprises following steps successively:

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

The transmitting node x of step 2 i-th hop link _iinquire about the neighbors table of self, acquisition can with transmitting node x _iagain can with the receiving node z of this hop link _icarry out all nodes communicated, the set that these nodes form is the candidate relay node set omega of this hop link _i;

The transmitting node x of step 3 i-th hop link _itraversal candidate relay set Ω _iin all nodes, calculate the throughput under the direct transmission mode of this hop link throughput under all possible single relay transmission pattern and the throughput under two relay transmission pattern this step comprises:

The transmitting node x of step 3.1 i-th hop 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 ^maxfor transmitting node x _itransmitting power, for the transmitting node x of current ink _iwith receiving node z _ibetween distance, α is path-loss factor, R ₀for information transmission rate, N ₀for noise; Further, transmitting node x _idetect candidate relay set Ω _iwhether be empty, if it is empty, then set the maximum throughput of single relay cooperative transmission link with the maximum throughput of two relay cooperative link be zero, and perform step 4, if not empty, then perform step 3.2;

The transmitting node x of step 3.2 i-th hop 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

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

Wherein, single relay cooperative transmission pattern lower node x _iand r _itransmitting power to be equally for transmitting node x _iwith destination node z _ibetween distance, for transmitting node x _iwith via node r _ibetween distance, for via node r _iwith destination node z _ibetween distance, α is path-loss factor, R ₀for information transmission rate, N ₀for noise; Pass through formula calculate the throughput of maximum single relay cooperative transmission link transmitting node x simultaneously _idetect candidate relay set Ω _imiddle candidate relay node number, if candidate relay node number is less than two, then sets equal zero, and perform step 4, otherwise, perform step 3.3;

The transmitting node x of step 3.3 i-th hop link _itravel through the candidate relay node of all combination of two as two relaying r _i ¹and r _i ²cooperation transmission time situation, calculate two relay cooperative transmission link (x _i, r _i ¹, r _i ², z _i) link throughput

$\begin{array}{c}{\mathrm{\η}}_{x_i,{r_i}^1,{r_i}^2,z_i}=(\exp \left({-\mathrm{gd}}_{x_i,z_i}^{\mathrm{\α}}\right)+\exp ({-\mathrm{gd}}_{x_i,{r_i}^1}^{\mathrm{\α}}-{\mathrm{gd}}_{r_{i1}^1,z_i}^{\mathrm{\α}})+\exp ({-\mathrm{gd}}_{x_i,{r_i}^2}^{\mathrm{\α}}-{\mathrm{gd}}_{r_2,z_i}^{\mathrm{\α}}))\\ -\exp ({-\mathrm{gd}}_{x_i,{r_i}^1}^{\mathrm{\α}}-{\mathrm{gd}}_{{r_i}^1,z_i}^{\mathrm{\α}}-{\mathrm{gd}}_{x_i,z_i}^{\mathrm{\α}})-\exp ({-\mathrm{gd}}_{x_i,{r_i}^2}^{\mathrm{\α}}-{\mathrm{gd}}_{{r_i}^2}^{\mathrm{\α}}-{\mathrm{gd}}_{x_i,z_i}^{\mathrm{\α}})\\ -\exp ({-\mathrm{gd}}_{x_i,{r_i}^2}^{\mathrm{\α}}-{\mathrm{gd}}_{{r_i}^2,z_i}^{\mathrm{\α}}-{\mathrm{gd}}_{x_i,{r_i}^1}^{\mathrm{\α}}-{\mathrm{gd}}_{{r_i}^1,z_i}^{\mathrm{\α}})+\exp ({-\mathrm{gd}}_{x_i,{r_i}^2}^{\mathrm{\α}}-{\mathrm{gd}}_{{r_i}^2,z_i}^{\mathrm{\α}}\\ -{\mathrm{gd}}_{x_i,{r_i}^1}^{\mathrm{\α}}-{\mathrm{gd}}_{{r_i}^1,z_i}^{\mathrm{\α}}-{\mathrm{gd}}_{x_i,z_i}^{\mathrm{\α}}\left)\right)\×R_0\end{array}$

Wherein, two relay cooperative transmission pattern lower node x _i, r _i ¹and r _i ²transmitting power to be equally for transmitting node x _iwith destination node z _ibetween distance, for transmitting node x _iwith via node r _i ^j, j ∈ the distance between 1,2}, for via node r _i ^jwith destination node z _ibetween distance, α is path-loss factor, R ₀for information transmission rate, N ₀for noise; Utilize formula calculate the throughput of maximum pair of relay cooperative transmission link

The throughput of the more direct transmission link of step 4 the throughput of maximum single relay cooperative transmission link with the throughput of maximum pair of relay cooperative transmission link size, maximum is wherein set as the maximum η of current ink throughput ^max; If the link throughput that the link directly under transmission mode is corresponding maximum, then perform step 5; If the link throughput that the link under single relay cooperative transmission pattern is corresponding maximum, then perform step 6; If the link throughput that the link under two relay cooperative transmission pattern is corresponding maximum, then perform step 7;

Step 5 sets current transmitting node x _itransmitting power be maximum transmission power P ^max, adopt direct mode to transfer data to receiving node z _i, and perform step 8;

The current transmitting node x of step 6 _ireceiving node z is forwarded packets to single relay cooperative transmission pattern by selected via node _i, this step comprises:

Step 6.1 is by link maximum throughput corresponding candidate relay node r _ias the single via node r chosen _i ^s;

Step 6.2 is by current transmitting node x _iwith via node r _i ^stransmitting power be all set as the 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 received, if the received signal to noise ratio of signal is greater than a specific thresholding, then think now via node r _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 forward transmitting node x _idata to receiving node z _i, and perform step 8; If received signal to noise ratio is less than specific threshold value, then thinks and decode unsuccessfully, abandon this packet, and perform step 8;

The current transmitting node x of step 7 _itwo relay cooperative transmission pattern is selected to forward packets to receiving node z _i, this step comprises:

The current transmitting node x of step 7.1 _iwill two corresponding candidate relay node with as two via nodes chosen with

Step 7.2 is to current transmitting node x _iwith two via nodes with carry out power setting, the transmitted power of these three nodes is all 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 received, if via node with the received signal to noise ratio detected is greater than a specific thresholding, then think now via node with can correctly receive transmitting node x _itransmission data, i.e. successfully decoded, then at the second time slot via node with respectively with transmitting power P ^max/ 3 forward from transmitting node x _idata to receiving node z _i, and perform step 8; Otherwise think and decode unsuccessfully, abandon this packet, and perform step 8;

Step 8 receiving node z _ito the decoding data received, if receiving node z _icorrectly have received transmitting node x _ior the via node r selected under single relay cooperative transmission pattern _i ^sor the via node selected under two relay cooperative transmission pattern with the signal sent, then perform step 9; Otherwise route data bust this, terminates the transmission of this route data;

Step 9 judges receiving node z _ibe whether the destination node d of routed path, if not, then by the receiving node z of current i-th hop link _ias the transmitting node x of the i-th+1 hop link _i+1, and return execution step 2; If receiving node z _ifor the destination node d of routed path, then route transmission data success, terminates the transmitting procedure of this routed path.