CN103826196B - Cross-layer optimization design method in multi-source multi-sink device-to-device relay communication system - Google Patents

Abstract

The invention provides a cross-layer optimization design method in a multi-source multi-sink device-to-device relay communication system. With the cross-layer optimization design method of the invention adopted, device-to-device (D2D) link performance can be enhanced, and system resource utilization rate can be improved, and the power of a device-to-device (D2D) transmitting side can be decreased, and interference on cellular users can be reduced, and greater performance improvement can be realized through cross-layer design and relay assist. The cross-layer optimization design method of the invention is a method for realizing relay communication usage for multi-source multi-sink device-to-device (D2D) users in the coexistence of the cellular users and the device-to-device (D2D) users. With the technical scheme of the invention adopted, each user in device-to-device (D2D) user clusters can use resources fairly, and great user experience can be realized. The method is suitable for a next-generation cellular system. The method relates to resource allocation and utilization by using graph theory classification and cross layer design.

Description

Cross-layer optimizing method for designing in the straightforward trunking communication system of multi-source many places

Technical field

The present invention relates to computer communication technology field, particularly in a kind of many places of multi-source based on terminal direct connection communication Continue communication means.

Background technology

It is introduced into straight-through technology (D2D) in conventional cellular systems can overcome in IMT-Advanced system with wirelessly many matchmakers The Zone centered on base station that body business development brings provides limitation in terms of adapting to local service development for the pattern, D2D technology can be improved network structure, strengthens covering, improves power system capacity.

But, the proposition of D2D technology brings new problem：The a lot of application scenarios of direct user are in high density user environment Under scene to big flow multi-medium data wilderness demand, this is accomplished by 1), base station assists to carry out suitable resource allocation to it； 2), the volume power consumption limit in user equipment makes the power of D2D communication and in the case of limited, efficient utilization resource；3)、 Ensure effectiveness, fairness and the reliability of Service Express, improve the Consumer's Experience of each direct user.

Above in order to solve the problems, such as, the present invention proposes to solve resource allocation problem by the method for graph theory and classification, with When association scheme are retransmitted by adaptive coding and modulating and hybrid automatic request can solve the efficient utilization of resource well and ask Topic.Scheme one side in the present invention can strengthen D2D link performance, lift system capacity, on the other hand can reduce D2D transmitting Square power, reduces and phone user is disturbed.

Content of the invention

Technical problem：Present invention aim at providing the cross-layer optimizing in a kind of straightforward trunking communication system of multi-source many places Method for designing, the method can strengthen D2D link performance, lift system resource utilization, and can reduce D2D launch party's work( Rate, reduces and phone user is disturbed, and will bring bigger performance boost by cross layer design and relaying auxiliary.

Technical scheme：The present invention solves its technical problem and is adopted the technical scheme that：The present invention is a kind of phone user When coexisting with D2D user, multi-source many places D2D user uses the implementation method of trunking traffic, and the method is to realize multi-source many places D2D Each user fairness uses resource in user's cluster, and the Consumer's Experience obtaining satisfaction provides scheme it is adaptable to Next generation cellular system, This method propose the resource allocation using graph theory classification and cross layer design and Utilizing question.

Method flow：

First, the term defining here is defined as follows：

BS：Base station

D2D：End-to-end

Ci：I-th phone user

SINR：Letter is dried ratio

HARQ：Hybrid automatic request retransmits

AMC：Adaptive coding and modulating mode

ACK：Receiving terminal is sent to the answer signal of transmitting terminal

M：In the alternative AMC scheme number of D2D link layer

N₀：Additive white Gaussian noise power

α：Path-loss factor

G (V, E)：End integrates as V, and side integrates the figure as E

v_i, i=1,2 ... n：The i-th end points in the collection V of end

e_i, i=1,2 ... n：During in collection E i-th

n：The number of end points is concentrated at end

α_ij, i, j ∈ V, i ≠ j：Node i transmits the expense required for per bit data on node j link

f₁, f₂：The frequency of direct user is distributed in base station

G：The figure being made up of end and side

G_p：Put fixed end collection

i：I-th node in cluster

G_i：I-stage puts fixed end collection

N_i：I-stage puts fixed end centralized node number

j：Do not put any point of fixed end concentration

G_i+1：I+1 level puts fixed end collection

N_i+1：I+1 level puts fixed end centralized node number

f_ij：The flow on node j link for the node i

d_ij：Node i is to the communication distance of node j

P_ij：Node i sends power required for node j for the per bit data

α_ij：The expense that transmission per bit data produces on link ij

r_ij：Message transmission rate on link ij

v_{I, l}, l=1,2 ... N_i：Set G_iIn element, represent i-stage node set in the 1st node v_{I+1, l}, l =1,2 ... N_i+1：Set G_i+1In element representation i+1 level node set in the 1st node, Φ (f_ij, P_ij)：Link ij The total cost function of upper generation

f_ki：Flow on even higher level of node k to this grade node i link

f_maxi：The maximum node flow of node i

f_maxij：Maximum link flow on link ij

d_ij：The distance between node i and j

h_ij：The path fading factor between node i and j

I：The jamming power that j node receives

γ_jth：J node is properly received received signal to noise ratio (SINR) threshold value of signal

P_mini：The least unit bit transmit power of node i

P_maxi：The maximum unit bit transmit power of node i

Cross-layer optimizing method for designing in multi-source many places straightforward trunking communication system of the present invention is realized as follows：

1) communication scenes

In cellular cell, may there is the scene of the intensive direct user in a large number of integrated distribution in a region, this area Intra domain user has same or different multimedia service to download demand, and such region is referred to as a cluster, the use in cluster Distributed direct communication is realized at family；Specifically communication mode is：There is a cluster head user, it is attached that this user first passes through it in cluster Near phone user obtains channel resource and corresponding multimedia service to base station requests, cluster head to base station apply for be one group can Channel resource, the position that channel is located according to cluster, using gridding frequency spectrum resource allocation method to required for the distribution of this cluster A class frequency resource；

User in cluster carries out to multimedia service data being classified relay forwarding, for cluster head user node, cluster head node Referred to as zero level node, zero level node is the node forwarding data, services in the range of communication distance to its application according to optimal between end Path principle is selected, selected node downloading data at cluster head node, meanwhile, the section of downloading data at cluster head node Point becomes first nodes, and first nodes are next stage node for data forwarding in the same way, by that analogy；In same first nodes In, there is no the node applied for service, continue to forward service in searching next stage node in the range of its communication distance Node, till finding；

2) the resource allocation flow process to direct user for the base station：

When cluster head is to base station application resource allocation, in addition it is also necessary to base station Shen in addition to the geographical position of this cluster of signals base Using frequency resource long enough, that in cluster and outside cluster, cellular system can not be produced with interference, base station please be covered Scope is divided into some net regions, and base station is in cluster according to the distance principle of " not producing interference in the range of efficient communication " User's dividing frequency resource；If user, using identical frequency resource, is to have when user applies for same business in cluster Profit, if needed between user, the traffic data type forwarding is different, and same frequency resource will be between user in cluster Produce interference, therefore, base station, when dividing frequency resource, needs to be allocated according to the state of affairs of user in cluster；As Fruit is same type business, and the frequency resource that base station can be to cluster head distribution in the area farther out of place cluster region, if cluster The data type that interior user is forwarded differs, then plural frequency resource is according to circumstances distributed to cluster head in base station；

The cluster head user of direct user cluster sends after resource request to base station, the position that base station is located according to cluster head user with The information of the scope with regard to cluster that cluster head user sends, the region that cluster is located is defined as 0 region, corresponding with cluster region Central angle is defined, and whole cellular system is divided into some regions by this central angle, and the region adjacent with 0th area is defined as I area, with The adjacent region in I area is defined as II area, by that analogy；Frequency resource allocation with the non-conterminous region in 0th area is used by base station in cluster Family, avoids in cluster between user with this and the interference between user and phone user in cluster；

3) cluster interior nodes user hierarchy plan

Defining cluster head node first is zero level node, is first nodes by the node definition of zero level node for data forwarding, All brother of nodes are defined as putting fixed end collection G_i, the number putting fixed end middle-end is the number of this grade of interior joint, according to this Divide, the resource using base station distribution can be coordinated during the link connection forwarding data in cluster interior nodes, that is,：The first order Forward usage frequency f1, the second level forwards usage frequency f2, the third level forwards usage frequency f1, the fourth stage forwards usage frequency F2, by that analogy, is effectively prevented from interfering in cluster；

Cluster interior nodes according to end between the principle that optimizes carry out the classification of node, concrete grammar is as follows：

Assume that node i is to put one of fixed end collection element, this is put fixed end collection and be defined as i level and puts fixed end collection G_iIt is assumed that collection A total N in conjunction_iIndividual node；Node j is any point not putting fixed end concentration, and this is not put fixed end collection and is defined as G_i+1, this set In end points to G_iBy node application forward data node constitute it is assumed that in gather one have N_i+1Individual node；By optimizing The node that scheme is selected is retained in set G_i+1In, update set interior joint number N simultaneously_i+1, remaining node is placed on next stage not put Fixed end collection G_i+2In, enter option program, the rest may be inferred；Define f_ijRepresent the flow on node j link for the node i, d_ijRepresent Node i is to the communication distance of node j, P_ijRepresent that from node i sends power required for node j for the per bit data, α_ijTable Show the expense that transmission per bit data produces on link ij, r_ijRepresent the message transmission rate on link ij, set G_i In element v_{I, l}, l=1,2 ... N_iRepresent the 1st node in i-stage node set, set G_i+1In element v_{I+1, l}, l= 1,2 ... N_i+1Represent the 1st node in i+1 level node set, defined function Φ (f_ij, P_ij) represent generation on link ij Total cost；

Optimization method is

Wherein, symbol f_kiRepresent the flow on even higher level of node k to this grade node i link, f_maxiRepresent the maximum of node i Node flow, f_maxijRepresent the maximum link flow on link ij, d_ijRepresent the distance between node i and j, h_ijRepresent node i The path fading factor and j between, I represents the jamming power that j node receives, γ_jthRepresent that j node is properly received connecing of signal Receive signal to noise ratio SINR threshold value, P_miniRepresent the least unit bit transmit power of node i, P_maxiRepresent the maximum unit of node i Bit transmit power；

Formula (2) conditional (a) is to enter row constraint to node flow, shows for the arbitrary node user in cluster, from This user goes out the flow of inflow, downloads to the flow of this node from even higher level of node, with this node users send flow it With the maximum node flow that should be equal to this node；

Formula (2) conditional (b) is the restriction to the message transmission rate on the flow and link on link, on link Actual flow should not be greater than the maximum stream flow on link, and link flow should be less than message transmission rate；

Formula (2) conditional (c) is that the transmission conditions on link are limited, and the SINR value on link must is fulfilled for The condition that the receiving terminal of direct user can be correctly decoded；

Formula (2) conditional (d) is the restriction to i-node user's transmit power, sends out from each link of i-node Send r_ijThe general power sum of bit data not can exceed that the maximum of i-node user sends general power；

Optimized by above, each node in i-stage node can select the next stage node set of oneself, simultaneously Update the number of element in respective next stage node set, and write in the routing table of i-node, carry out for data transfer afterwards Prepare；

4) cluster interior nodes user classification flow process

Cluster head user applies for the flow process of resource to base station：

Step one：The user of i-stage node is to the user's broadcast message in its communication range；

Step 2：If there are in the range of its efficient communication download need node users, then this user just to This i level user replys a confirmation signal；

Step 3：This i level user selects to all of application user according to Optimality Criteria between end, and to selected user Send confirmation, set up communication link, selected node definition is to put fixed end collection G simultaneously_i+1；

Step 4：Do not have to apply for that the user arriving continues to send service request, the G into its communication range_i+1Select in set Accept the node of service；

5) lead directly to link efficient transmission scheme

Once communication link is successfully established, the specific implementation step of the efficient transmission scheme on link is：

Step 502：Communication link is set up between node；

Step 504：I+1 level node users belonging to it for the i level node users send data；

Step 506：The SINR value first according to current detection for the i level node users selects corresponding AMC scheme, according to corresponding Scheme data is encoded and is modulated；

Step 508：Send data；

Step 510：I level node users wait whether receiving terminal has correctly received the confirmation of signal, if correctly connect Receive, turn to step 514, otherwise turn to step 512；

Step 512：If transmitting terminal does not receive the ACK of receiving terminal, transmitting terminal starts HARQ mechanism, judges whether to surpass Cross maximum retransmission, without then turning to step 508, until reaching maximum transmission times, if being not reaching to maximum Just receive ACK during the number of transmissions, then entered step 508, otherwise terminated HARQ, turn to step 516；

Step 514：Judge data whether end of transmission, if end of transmission, turn to step 520, otherwise, turn to step 508；

Step 516：Transvalue SINR；

Step 518：Judge whether SINR changes, if SINR value not becoming, illustrating that this channel is not suitable for straight-through transmission, turning to Step 502, direct user applies for available resources to base station again, if SINR value changes, turns to step 506, direct user Transmitting terminal, according to the SINR value of change, adjusts AMC scheme, is continuing with this channel and sends data, until DTD；

Step 520：Release channel.

Beneficial effect：

1st, the present invention proposes the resource allocation using graph theory classification and cross layer design and Utilizing question, and the method is effectively Improve the resource utilization of cellular system, increased throughput of system, expand the coverage of power system capacity and cell.

2nd, the present invention improves same by the way of adaptive coding and modulating and hybrid automatic request retransmit and combine The validity and reliability of region D2D communication.

Brief description

Fig. 1 is straight-through multi-source many places trunking traffic scene graph of the present invention；

Fig. 2 is the zoning plan to frequency resource for the base station that the present invention adopts；

Fig. 3 is cluster interior nodes user's classification figure that the present invention adopts；

Fig. 4 is the resource allocation flow chart to direct user cluster for the base station that the present invention adopts；

Fig. 5 is that the direct user of the present invention adopts AMC and HARH association scheme using the flow chart of resource.

Specific embodiment

The invention provides the cross-layer optimizing method for designing in a kind of straightforward trunking communication system of multi-source many places, the method is Multi-source many Su Zhongji implementation method based on cellular system：

Communication scenes (as shown in Figure 1)

In cellular cell, may there is the scene of the intensive direct user in a large number of integrated distribution in a region, for example Convention place, market or big sport place etc., this area's intra domain user has same or different multimedia service Download demand, such region is referred to as a cluster by us, and the user in cluster realizes distributed direct communication.Specific communication Mode is：There is a cluster head user, this user first passes through its neighbouring phone user and obtains channel money to base station requests in cluster Source and corresponding multimedia service, what cluster head was applied for base station is one group of available channel resource, the position that channel is located according to cluster Put, using gridding frequency spectrum resource allocation method to the required class frequency resource of this cluster distribution.

User in cluster carries out to multimedia service data being classified relay forwarding, cluster head section taking cluster head user node as a example Point be referred to as zero level node, zero level node in the range of communication distance to its application forward data, services node according to end Good path principle is selected, selected node can at cluster head node downloading data, meanwhile, download number at cluster head node According to node become first nodes, first nodes in the same way be next stage node for data forwarding, by that analogy.Same In level node, there is no the node applied for service, continue to find in next stage node in the range of its communication distance and can forward The node of service, till finding.

1st, the area division scheme to frequency resource for the base station

As shown in Fig. 2 the cluster head user of direct user cluster sends after resource request to base station, base station is according to cluster head user institute Position and the information of the scope with regard to cluster sent of cluster head user, the region that cluster is located is defined as 0 region, is located with cluster The corresponding central angle in region is defined, and whole cellular system is divided into some regions by this central angle, and the region adjacent with 0th area is fixed Justice is I area, and the region adjacent with I area is defined as II area, by that analogy.Base station is by the frequency in region distant for distance 0 area Resource allocation to user in cluster, avoids in cluster between user with this and the interference between user and phone user in cluster.

2nd, cluster interior nodes user hierarchy plan

Cluster interior nodes hierarchy plan, as shown in figure 3, defining cluster head node first is zero level node, is forwarded by zero level node The node definition of data is first nodes, and all brother of nodes are defined as putting fixed end collection G_i, the number putting fixed end middle-end is The number of this grade of interior joint.According to this division, can coordinate to make during the link connection forwarding data in cluster interior nodes With the resource of base station distribution, a kind of scheme of simple possible is：The first order forwards usage frequency f1, and the second level forwards usage frequency F2, the third level forwards usage frequency f1, and the fourth stage forwards usage frequency f2, by that analogy, can be effectively prevented from the phase in cluster Mutually disturb.

Cluster interior nodes according to end between the principle that optimizes carry out the classification of node, concrete grammar is as follows：

Assume that node i is to put one of fixed end collection element, this is put fixed end collection and be defined as i level and puts fixed end collection G_iIt is assumed that collection A total N in conjunction_iIndividual node.Node j is any point not putting fixed end concentration, and this is not put fixed end collection and is defined as G_i+1, this set In end points to G_iBy node application forward data node constitute it is assumed that in gather one have N_i+1Individual node.By optimizing The node that scheme is selected is retained in set G_i+1In, update set interior joint number N simultaneously_i+1, remaining node is placed on next stage not put Fixed end collection G_i+2In, enter option program, the rest may be inferred.Define f_ijRepresent the flow on node j link for the node i, d_ijRepresent Node i is to the communication distance of node j, P_ijRepresent that from node i sends power required for node j for the per bit data, α_ijTable Show the expense that transmission per bit data produces on link ij, r_ijRepresent the message transmission rate on link ij, set G_i In element v_{I, l}, l=1,2 ... N_iRepresent l-th node in i-stage node set, set G_i+1In element v_{I+1, l}, l= 1,2 ... N_i+1Represent l-th node in i+1 level node set, defined function Φ (f_ij, P_ij) represent generation on link ij Total cost.

Optimization method is

Wherein, symbol f_kiRepresent the flow on even higher level of node k to this grade node i link, f_maxiRepresent the maximum of node i Node flow, f_maxijRepresent the maximum link flow on link ij, d_ijRepresent the distance between node i and j, h_ijRepresent node i The path fading factor and j between, I represents the jamming power that j node receives, γ_jthRepresent that j node is properly received connecing of signal Receive signal to noise ratio (SINR) threshold value, P_miniRepresent the least unit bit transmit power of node i, P_maxiRepresent the maximum single of node i Position bit transmit power.

Formula conditional (2.a) is to enter row constraint to node flow, shows for the arbitrary node user in cluster, from this User goes out the flow of inflow, downloads to the flow of this node from even higher level of node, the flow sum sending with this node users The maximum node flow of this node should be equal to.

Formula conditional (2.b) is the restriction to the message transmission rate on the flow and link on link, on link Actual flow should not be greater than the maximum stream flow on link, and link flow should be less than message transmission rate；

Formula conditional (2.c) is that the transmission conditions on link are limited, and the SINR value on link must is fulfilled for The condition that the receiving terminal of direct user can be correctly decoded.

Formula conditional (2.d) is the restriction to i-node user's transmit power, sends out from each link of i-node Send r_ijThe general power sum of bit data not can exceed that the maximum of i-node user sends general power.

Optimized by above, each node in i-stage node can select the next stage node set of oneself, simultaneously Update the number of element in respective next stage node set, and write in the routing table of i-node, carry out for data transfer afterwards Prepare.

3rd, cluster interior nodes user classification flow process

To base station, cluster head user applies for that the flow chart of resource is as shown in Figure 4：

Step one：The user of i-stage node is to the user's broadcast message in its communication range；

Step 2：If there are in the range of its efficient communication download need node users, then this user just to This i level user replys a confirmation signal；

Step 3：This i level user selects to all of application user according to Optimality Criteria between end, and to selected user Send confirmation, set up communication link, selected node definition is to put fixed end collection G simultaneously_i+1；

Step 4：Do not have to apply for that the user arriving continues to send service request, the G into its communication range_i+1Select in set Accept the node of service；

4th, lead directly to link efficient transmission scheme

Once communication link is successfully established, the specific implementation step of the efficient transmission scheme on link is：

Step 502：Communication link is set up between node；

Step 504：I+1 level node users belonging to it for the i level node users send data；

Step 506：The SINR value first according to current detection for the i level node users selects corresponding AMC scheme, according to corresponding Scheme data is encoded and is modulated；

Step 508：Send data；

Step 510：I level node users wait whether receiving terminal has correctly received the confirmation of signal, if correctly connect Receive, turn to step 514, otherwise turn to step 512；

Step 512：If transmitting terminal does not receive the ACK of receiving terminal, transmitting terminal starts HARQ mechanism, judges whether to surpass Cross maximum retransmission, without then turning to step 514, until reaching maximum transmission times, if being not reaching to maximum Just receive ACK during the number of transmissions, then entered step 514, otherwise terminated HARQ, turn to step 516；

Step 514：Judge data whether end of transmission, if end of transmission, turn to step 520, otherwise, turn to step 508；

Step 516：Transvalue SINR；

Step 518：Judge whether SINR changes, if SINR value not becoming, illustrating that this channel is not suitable for straight-through transmission, turning to Step 502, direct user applies for available resources to base station again, if SINR value changes, turns to step 506, direct user Transmitting terminal, according to the SINR value of change, adjusts AMC scheme, is continuing with this channel and sends data, until DTD；

Step 520：Release channel.

Claims (1)

1. the cross-layer optimizing method for designing in a kind of straightforward trunking communication system of multi-source many places is it is characterised in that the method is realized As follows：

1) communication scenes

In cellular cell, may there is the scene of the intensive direct user in a large number of integrated distribution in a region, in this region User has same or different multimedia service to download demand, and such region is referred to as a cluster, and the user in cluster is real Existing distributed direct communication；Specifically communication mode is：There is a cluster head user, it is neighbouring that this user first passes through it in cluster Phone user obtains channel resource and corresponding multimedia service to base station requests, cluster head to base station apply for be one group available Channel resource, the position that channel is located according to cluster, required for being distributed to this cluster using gridding frequency spectrum resource allocation method Class frequency resource；

User in cluster carries out to multimedia service data being classified relay forwarding, and for cluster head user node, cluster head node is referred to as Zero level node, zero level node is the node forwarding data, services in the range of communication distance to its application according to optimal path between end Principle is selected, selected node downloading data at cluster head node, and meanwhile, at cluster head node, the node of downloading data becomes For first nodes, first nodes are next stage node for data forwarding in the same way, by that analogy；In same first nodes, There is no the node applied for service, continue to find the section that can forward service in next stage node in the range of its communication distance Point, till finding；

2) the resource allocation flow process to direct user for the base station：

Cluster head to base station application resource allocation when, except the geographical position of this cluster of signals base in addition in addition it is also necessary to base station apply for can Using frequency resource long enough, that in cluster and outside cluster, cellular system can not be produced with interference, by base station range It is divided into some net regions, base station is user in cluster according to the distance principle of " not producing interference in the range of efficient communication " Dividing frequency resource；If user, using identical frequency resource, is favourable when user applies for same business in cluster, If needed between user, the traffic data type forwarding is different, and same frequency resource will produce dry between user in cluster Disturb, therefore, base station, when dividing frequency resource, needs to be allocated according to the state of affairs of user in cluster；If phase Same type business, the frequency resource that base station can be to cluster head distribution in the area farther out of place cluster region, if user in cluster The data type being forwarded differs, then plural frequency resource is according to circumstances distributed to cluster head in base station；

The cluster head user of direct user cluster sends after resource request to base station, position and cluster head that base station is located according to cluster head user The information of the scope with regard to cluster that user sends, the region that cluster is located is defined as 0 region, with the corresponding center of circle in cluster region Angle is defined, and whole cellular system is divided into some regions by this central angle, and the region adjacent with 0th area is defined as I area, with I area Adjacent region is defined as II area, by that analogy；Base station by the frequency resource allocation with the non-conterminous region in 0th area to user in cluster, Avoid in cluster between user with this and the interference between user and phone user in cluster；

3) cluster interior nodes user hierarchy plan

Defining cluster head node first is zero level node, is first nodes by the node definition of zero level node for data forwarding, owns The brother of node is defined as putting fixed end collection G_i, the number putting fixed end middle-end is the number of this grade of interior joint, according to this division, The resource using base station distribution can be coordinated in cluster interior nodes during the link connection forwarding data, that is,：The first order forwards Usage frequency f1, the second level forwards usage frequency f2, and the third level forwards usage frequency f1, and the fourth stage forwards usage frequency f2, with This analogizes, and is effectively prevented from interfering in cluster；

Cluster interior nodes according to end between the principle that optimizes carry out the classification of node, concrete grammar is as follows：

Assume that node i is to put one of fixed end collection element, this is put fixed end collection and be defined as i level and puts fixed end collection G_iIt is assumed that one in set Total N_iIndividual node；Node j is any point not putting fixed end concentration, and this is not put fixed end collection and is defined as G_i+1, end in this set Point is to G_iBy node application forward data node constitute it is assumed that in gather one have N_i+1Individual node；Selected by prioritization scheme The node going out is retained in set G_i+1In, update set interior joint number N simultaneously_i+1, remaining node is placed on next stage not put fixed end collection G_i+2In, enter option program, the rest may be inferred；Define f_ijRepresent the flow on node j link for the node i, d_ijRepresent that node i arrives The communication distance of node j, P_ijRepresent that from node i sends power required for node j for the per bit data, α_ijRepresent in chain The expense that on the ij of road, transmission per bit data produces, r_ijRepresent the message transmission rate on link ij, set G_iIn unit Plain v_{I, l}, l=1,2 ... N_iRepresent l-th node in i-stage node set, set G_i+1In element v_{I+1, l}, l=1,2 ... N_i+1Represent l-th node in i+1 level node set, defined function Φ (f_ij, P_ij) represent that on link ij, the total of generation is taken With；

$\begin{array}{c}\mathrm{\Φ}(f_{ij},P_{ij})=\underset{j\∈G_{i+1}}{\mathrm{\Σ}}{\mathrm{\α}}_{ij}{f}_{ij}+\underset{j\∈G_{i+1}}{\mathrm{\Σ}}{r}_{ij}{P}_{ij},G_{ij}=\{v_{i+1,1},v_{i+1,2},...v_{i+1,N_{i+1}}\}\\ i\∈G_i,G_i=\{v_{i,1},v_{i,2},...v_{i,N_i}\}\end{array},---\left(1\right)$

Optimization method is

$\begin{array}{ccc}\min imize& \mathrm{\Φ}(f_{ij},P_{ij})& \\ subjectto& \underset{j\∈G_{i+1}}{\mathrm{\Σ}}{f}_{ij}-\underset{k\∈G_{i-1}}{\mathrm{\Σ}}{f}_{ki}=f_{\max i}& \left(a\right)\\ & 0\≤f_{ij}\≤f_{\max ij},f_{ij}\≤r_{ij}& \left(b\right)\\ & d_{ij}^{-\mathrm{\α}}|h_{ij}{|}^2{P}_{ij}\≥{\mathrm{I\γ}}_{jth}& \left(c\right)\\ & f_{\max i}{P}_{\min i}\≤\underset{j\∈G_{i+1}}{\mathrm{\Σ}}{r}_{ij}{P}_{ij}\≤f_{\max i}{P}_{\min i}& \left(d\right)\end{array}---\left(2\right)$

Wherein, symbol α represents path-loss factor, symbol f_kiRepresent the flow on even higher level of node k to this grade node i link, f_maxiRepresent the maximum node flow of node i, f_maxijRepresent the maximum link flow on link ij, d_ijRepresent between node i and j Distance, h_ijRepresent the path fading factor between node i and j, I represents the jamming power that j node receives, γ_jthRepresent j section Point is properly received the received signal to noise ratio SINR threshold value of signal, P_miniRepresent the least unit bit transmit power of node i, P_maxi Represent the maximum unit bit transmit power of node i；

Formula (2) conditional (a) is to enter row constraint to node flow, shows for the arbitrary node user in cluster, from this use Family goes out the flow of inflow, downloads to the flow of this node from even higher level of node, and the flow sum sending with this node users should The maximum node flow of this node should be equal to；

Formula (2) conditional (b) is the restriction to the message transmission rate on the flow and link on link, the reality on link Flow should not be greater than the maximum stream flow on link, and link flow should be less than message transmission rate；

Formula (2) conditional (c) is that the transmission conditions on link are limited, and the SINR value on link must is fulfilled for straight-through The condition that the receiving terminal of user can be correctly decoded；

Formula (2) conditional (d) is the restriction to i-node user's transmit power, sends r from each link of i-node_ij The general power sum of bit data not can exceed that the maximum of i-node user sends general power；

Optimized by above, each node in i-stage node can be selected the next stage node set of oneself, update simultaneously The number of element in respective next stage node set, and write in the routing table of i-node, carry out standard for data transfer afterwards Standby；

4) cluster interior nodes user classification flow process

Cluster head user applies for the flow process of resource to base station：

Step one：The user of i-stage node is to the user's broadcast message in its communication range；

Step 2：If there are in the range of its efficient communication downloading the node users needing, then this user is just to this i level User replys a confirmation signal；

Step 3：This i level user selects to all of application user according to Optimality Criteria between end, and sends to selected user Confirmation, sets up communication link, and selected node definition is to put fixed end collection G simultaneously_i+1；

Step 4：Do not have to apply for that the user arriving continues to send service request, the G into its communication range_i+1Select in set to accept The node of service；

5) lead directly to link efficient transmission scheme

Once communication link is successfully established, the specific implementation step of the efficient transmission scheme on link is：

Step 502：Communication link is set up between node；

Step 504：I+1 level node users belonging to it for the i level node users send data；

Step 506：The SINR value first according to current detection for the i level node users selects corresponding AMC scheme, according to corresponding side Case is encoded to data and is modulated；

Step 508：Send data；

Step 510：I level node users wait whether receiving terminal has correctly received the confirmation of signal, if be properly received, turn To step 514, otherwise turn to step 512；

Step 512：If transmitting terminal does not receive the ACK of receiving terminal, transmitting terminal starts HARQ mechanism, judges whether to exceed Big number of retransmissions, without then turning to step 508, until reaching maximum transmission times, if be not reaching to maximum transmitted Just receive ACK during number of times, then entered step 508, otherwise terminated HARQ, turn to step 516；

Step 514：Judge data whether end of transmission, if end of transmission, turn to step 520, otherwise, turn to step 508；

Step 516：Transvalue SINR；

Step 518：Judge whether SINR changes, if SINR value not becoming, illustrating that this channel is not suitable for straight-through transmission, turning to step 502, direct user applies for available resources to base station again, if SINR value changes, turns to step 506, direct user sends End, according to the SINR value of change, adjusts AMC scheme, is continuing with this channel and sends data, until DTD；

Step 520：Release channel.