CN103118381A - Method and system utilizing vehicle ad hoc network to reduce downloading of the third generation telecommunication (3G) shared data - Google Patents

Abstract

The invention discloses a method and a system utilizing a vehicle ad hoc network to reduce the downloading of the third generation telecommunication (3G) shared data. The method includes the following steps: initializing a system, obtaining vehicle history encounter information and data information which needs to be downloaded, obtaining a vehicle collection of the data; determining to-be-executed times of a multistage strategy; calculating a downloading strategy based on the vehicle encounter information and by combining transmission requirement with a current transmission condition, describing an optimizing problem of 3G downloading, solving the optimization problem and making a responding decision, downloading data through 3G, transmitting the data to a vehicle node which needs the data through a vehicle transmission network, repeating the step according to the determined executed times; and all vehicle nodes which do not obtain data download corresponding data through 3G. The method and the system utilizing the vehicle ad hoc network to reduce the downloading of the 3G shared data is capable of not only reducing expenses of 3G downloading, but also meeting an aging requirement of data transmission.

Description

Utilize the car self-organization network network to reduce 3G and share the method and system that data are downloaded

Technical field

The method and system that the present invention downloads about a kind of 3G data particularly relate to a kind of car self-organization network network that utilizes and reduce the method and system that 3G shares the data download.

Background technology

Vehicle network is emerging in recent years network, and various countries are used for the standard of the Dedicated Short RangeCommunications (Dedicated Short Range Communications, technology) of vehicle network and are also formulating and improving.Vehicle self-organizing network is comprised of vehicle node, carry out radio communication by the Wireless Telecom Equipment of installing on vehicle, transceiving data with realize between vehicle, multi-hop wireless communication between vehicle and static infrastructure, be built into the mobile radio network that can complete point to point link.Therefore in this network, each car is all the routing node of whole network, realizes the interconnected of vehicle in whole city.The shortcoming of vehicle network is that coverage is little, and the network connection is unstable, and propagation delay time is high.Advantage is to spend substantially to ignore, and transmission rate is high.

3 G mobile communication network (3rd-generation, 3G) is being used now widely.Mobile device all is equipped with as notebook computer, smart mobile phone the radio communication that the 3G module realizes high-speed, wide scope.3G communication has the advantages such as communication range is wide, and speed is fast.Yet, cause the download that the user can not be random because rate are more expensive and must consider the rate problem.

Many mixture of networks network model is repeatedly discussed at academic and practise area.System discussed here is 3G, vehicle hybrid network, and the vehicle node in vehicle network not only can be completed transfer of data by short haul connection, can also access the 3G module and carry out data download (such as downloading map lastest imformation etc.).It solves the problem of following scene: a son set in vehicle network needs to download identical data, and these class data can only be downloaded by 3G network at the beginning.Because 3G download to need the certain expense of payment operator, so being each car in set, the highest method of cost downloads separately by 3G, this method cost is maximum but time delay is minimum.The another one method be individual node in set by the 3G downloading data, and then pass to other vehicle node in set by vehicle network.Although this method least cost because the vehicle network transmission delay is higher, causes part of nodes can not receive the data that needs are downloaded in certain timeliness.

Summary of the invention

For overcoming above-mentioned the deficiencies in the prior art, the present invention's purpose is to provide a kind of car self-organization network network that utilizes to reduce the method and system that 3G shares the data download, it is downloaded in conjunction with the auxiliary 3G of car self-organization network network, realize both having reduced the cost that 3G downloads, satisfy again the purpose of the timeliness requirement of transfer of data.

For reaching above-mentioned and other purpose, the invention provides a kind of car self-organization network network that utilizes and reduce the system that 3G shares the data download, comprise at least:

The initialization module is used for system initialization, obtains the data message that vehicle history is met information and needed download, and obtaining simultaneously needs the set of the vehicle of these data;

Carry out number of times and determine module, be used for determining that the multistage strategy needs the number of times of carrying out;

Module is calculated and processed to download policy, according to the execution number of times of determining, be repeated below process: the historical information of meeting based on vehicle, calculate download policy in conjunction with transmission requirement and current transmission situation, depict the optimization problem that 3G downloads, find the solution this optimization problem and make corresponding download decision, the data of downloading by 3G are transferred to by vehicle network the vehicle node that needs these data again; And

3G downloads module, and before the last moment of the timeliness restriction that arrives downloading request, the vehicle node that makes all not obtain data is downloaded corresponding data by 3G network.

Further, this download policy calculating and processing module also comprise:

The transmission situation is collected module, is used for collecting the transmission situation;

Weight is upgraded module, according to transmission situation and the vehicle node local cache information of the current network of collecting, upgrades the weight of to be selected kind of child node;

Optimization problem is portrayed module, download problem is formulated for optimization problem, and target is to minimize the data volume of downloading by 3G, and constraint is the data that each vehicle node will be obtained before time-constrain needs download, and find the solution this optimization problem, obtain approximate optimal solution;

The transfer of data module utilizes the transmittability of car self-organization network network, uses the double bounce transmission that data are transmitted in vehicle network.

Further, this transmission situation comprises the number that needs the packet that transmits in the buffer memory of each vehicle node and the packet of transmission success.

Further, this optimization problem is portrayed module and in the following way download problem is formulated for optimization problem:

Minimize: $\underset{u_i\∈U}{\mathrm{\Σ}}\underset{p_k\∈P}{\mathrm{\Σ}}{X}_i^{\left(k\right)}$

Be constrained in: $\frac{\left|\right|W_{\mathrm{avg}}\left(k\right)\left(T\right)\left|\right|}{\left|\right|W_c\left|\right|}\·\mathrm{Cos}\_\mathrm{Sim}(W_{\mathrm{avg}}\left(k\right)\left(T\right),W_c)\≥1-\mathrm{\δ}$

W _c＝{ε，ε，ε，...}

Meter for vehicle in vehicle network is shown a set V={v ₁, v ₂, v ₃..., v _n, wherein V son is gathered U={u ₁, u ₂, u ₃..., u _mFor needing the vehicle identifiers of downloading data bag, set P={p ₁, p ₂..., p _kPacket that need to download of representative,

Expression vehicle u _iDownloading data p _k, vector $W^{\left(k\right)}\left(T\right){=}_{u_j\∈U}(\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{i1}^{\left(k\right)}T,...,\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{\mathrm{ij}}^{\left(k\right)}T),$ $W_{\mathrm{avg}}^{\left(k\right)}\left(T\right)=\frac{1}{\left|P\right|}\underset{k\∈P}{\mathrm{\Σ}}{W}^{\left(k\right)}\left(T\right).$

Further, this optimization problem is portrayed module and is found the solution this optimization problem by greedy algorithm.

For reaching above-mentioned and other problem, the present invention also provides a kind of car self-organization network network that utilizes to reduce the method that 3G shares the data download, comprises the steps:

Step 1, system initialization obtains the data message that vehicle history is met information and needed download, and obtaining simultaneously needs the set of the vehicle of these data;

Step 2 determines that the multistage strategy needs the number of times of carrying out;

Step 3, the historical information of meeting based on vehicle, calculate download policy in conjunction with transmission requirement and current transmission situation, depict the optimization problem that 3G downloads, find the solution this optimization problem and make corresponding download and determine, the data of downloading by 3G are transferred to by vehicle network the vehicle node that needs these data again, and according to the execution number of times that step 2 is determined, repeat this step; And

Step 4, before the last moment of the timeliness restricted T that arrives downloading request, all do not obtain the vehicle node of data and download corresponding data by 3G.

Further, step 3 also comprises the steps:

Collect the transmission situation;

According to transmission situation and the vehicle node local cache information of the current network of collecting, upgrade the weight of to be selected kind of child node;

Download problem is formulated for optimization problem, and target is to minimize the data volume of downloading by 3G, and constraint is the data that each vehicle node will be obtained before time-constrain needs download, and finds the solution this optimization problem, obtains approximate optimal solution; And

Utilize the transmittability of vehicle self-organizing network, use the double bounce transmission that data are transmitted in vehicle network.

Further, this collection transmission situation transmission situation of collecting comprises the number that needs the packet that transmits in the buffer memory of each vehicle node and the packet of transmission success.

Further, this is formulated for the optimization problem step with download problem and in the following way download problem is formulated for optimization problem,

Minimize: $\underset{u_i\∈U}{\mathrm{\Σ}}\underset{p_k\∈P}{\mathrm{\Σ}}{X}_i^{\left(k\right)}$

Be constrained in: $\frac{\left|\right|W_{\mathrm{avg}}\left(k\right)\left(T\right)\left|\right|}{\left|\right|W_c\left|\right|}\·\mathrm{Cos}\_\mathrm{Sim}(W_{\mathrm{avg}}\left(k\right)\left(T\right),W_c)\≥1-\mathrm{\δ}$

W _c＝{ε，ε，ε，...}

Meter for vehicle in vehicle network is shown a set V={v ₁, v ₂, v ₃..., v _n, wherein V son is gathered U={u ₁, u ₂, u ₃..., u _mFor needing the vehicle identifiers of downloading data bag, set P={p ₁, p ₂..., p _kPacket that need to download of representative,

Expression vehicle u _iDownloading data p _k, vector $W^{\left(k\right)}\left(T\right){=}_{u_j\∈U}(\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{i1}^{\left(k\right)}T,...,\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{\mathrm{ij}}^{\left(k\right)}T),$ $W_{\mathrm{avg}}^{\left(k\right)}\left(T\right)=\frac{1}{\left|P\right|}\underset{k\∈P}{\mathrm{\Σ}}{W}^{\left(k\right)}\left(T\right).$

Further, utilize greedy algorithm to find the solution this optimization problem in step 3.

Compared with prior art, the present invention is a kind of to be utilized the car self-organization network network to reduce 3G to share method and system that data download based on the history of the vehicle information of meeting, by choosing the kind child node that is conducive to the vehicle network transmission most, the transmittability that takes full advantage of vehicle network is given data packet delivery the destination node that needs this packet, utilize the car self-organization network network, reach and both satisfy transmission requirement, reduce again the application target of 3G download.

Description of drawings

Fig. 1 is that a kind of car self-organization network network that utilizes of the present invention reduces the system of systems Organization Chart that 3G shares the data download;

Fig. 2 is that a kind of car self-organization network network that utilizes of the present invention reduces the flow chart of steps that 3G shares the method for data download;

Fig. 3 is the timeliness schematic diagram of preferred embodiment of the present invention;

Fig. 4 is that a kind of car self-organization network network that utilizes of the present invention reduces the flow chart of steps that 3G shares the preferred embodiment of the method that data download.

Embodiment

Below by specific instantiation and accompanying drawings embodiments of the present invention, those skilled in the art can understand other advantage of the present invention and effect easily by content disclosed in the present specification.The present invention also can be implemented or be used by other different instantiation, and the every details in this specification also can be based on different viewpoints and application, carries out various modifications and change under spirit of the present invention not deviating from.

Before describing the present invention, the proper noun of using in paper the present invention:

(1) 3G, vehicle network hybrid network: vehicle is as mobile node, equipped vehicle network common Dedicated Short Range Communications (Dedicated Short Range Communications, technology) on car and has been used for communication between vehicle.Also equip simultaneously the 3G access device on vehicle and be used for accessing existing 3G network.

(2) the vehicle history information of meeting: in statistics a period of time, the adjacent twice required time of meeting (interval Encounter Time) between vehicle and vehicle.Studies show that before, the interval Encounter Time index of coincidence between vehicle distributes.

(3) multistage: before whole data were downloaded the deadline, node was repeatedly made and is downloaded the number of times that determines.

(4) plant child node: by the vehicle node of 3G technology downloading data content.

(5) downloading request: be directed to each data, need the vehicle node of these data to download by 3G before the time T of appointment or to obtain by vehicle network.

Fig. 1 is that a kind of car self-organization network network that utilizes of the present invention reduces the system of systems Organization Chart that 3G shares the data download.As shown in Figure 1, a kind of car self-organization network network that utilizes of the present invention reduces the system that 3G shares the data download, be used for 3G, vehicle network hybrid network, comprise at least: initialization module 10, execution number of times determine that module 11, download policy are calculated and processing module 12 and 3G download module 13.

Wherein initialization module 10 is used for system initialization, obtains data number, number that vehicle history is met information and needed download, and obtaining simultaneously needs the set of the vehicle of these data; Carry out number of times and determine that module 11 is used for determining that the multistage strategy needs the number of times of carrying out; Module 12 is calculated and processed to download policy according to the execution number of times of determining, be repeated below process: the historical information of meeting based on vehicle, calculate download policy in conjunction with transmission requirement and current transmission situation, depict the optimization problem that 3G downloads, find the solution this optimization problem and make corresponding download decision, the data of downloading by 3G are transferred to by vehicle network the vehicle node that needs these data again; 3G downloads module 13 and was used for before the last moment of the timeliness restricted T that arrives downloading request, and the vehicle node that makes all not obtain data is downloaded corresponding data by 3G network.

Specifically, download policy is calculated and processed module 12 and further comprises: transmission situation collection module 120, weight are upgraded module 121, optimization problem is portrayed module 122 and transfer of data module 123, the transmission situation is collected module 120 and is used for collecting the transmission situation, comprise the number that needs the packet that transmits in the buffer memory of each vehicle node, the information such as packet of transmission success; Weight is upgraded module 121, according to transmission situation and the vehicle node local cache information of the current network of collecting, upgrades the weight of to be selected kind of child node; Optimization problem is portrayed module 122 download problem is formulated for optimization problem, target is to minimize the data volume of downloading by 3G, constraint is the data that each vehicle node will be obtained before time-constrain needs download, by this optimization problem of greedy algorithm solution, obtains approximate optimal solution; Transfer of data module 123 utilizes the transmittability of car self-organization network network, uses the double bounce transmission that data are transmitted in vehicle network.

Optimization problem is portrayed in module 122:

Minimize: $\underset{u_i\∈U}{\mathrm{\Σ}}\underset{p_k\∈P}{\mathrm{\Σ}}{X}_i^{\left(k\right)}$

Be constrained in: $\frac{\left|\right|W_{\mathrm{avg}}\left(k\right)\left(T\right)\left|\right|}{\left|\right|W_c\left|\right|}\·\mathrm{Cos}\_\mathrm{Sim}(W_{\mathrm{avg}}\left(k\right)\left(T\right),W_c)\≥1-\mathrm{\δ}$

W _c＝{ε，ε，ε，...}

(1) meter for vehicle in vehicle network is shown a set V={v ₁, v ₂, v ₃..., v _n, wherein V son is gathered U={u ₁, u ₂, u ₃..., u _mFor needing the vehicle identifiers of downloading data bag, set P={p ₁, p ₂..., p _kPacket that need to download of representative.

Expression vehicle u _iDownloading data p _kVector $W^{\left(k\right)}\left(T\right){=}_{u_j\∈U}(\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{i1}^{\left(k\right)}T,...,\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{\mathrm{ij}}^{\left(k\right)}T)$ Represent wherein set expression.For packet p _k, select by through electing the vehicle S set of data kind child node as ^(k), packet p _kArrive the weight of each destination node.Wherein $W_{\mathrm{avg}}^{\left(k\right)}\left(T\right)=\frac{1}{\left|P\right|}\underset{k\∈P}{\mathrm{\Σ}}{W}^{\left(k\right)}\left(T\right).$ Expression is for all data that need to download, the mean value of seed node weights to be selected.

(2) each w in weight vectors W _ij ^(k)(T) u is chosen in expression _iFor kind of a child node downloading data bag pk arrived destination node u before data age T _jWeight.

(3) vectorial W _cBe the constant vector, can determine that the transmission requirement that will reach, ε are generally less than 1 and very little numerical value by the value that changes ε.

(4)

The Length Ratio of expression weight vectors and constrained vector, the cosine similarity of two vectors is found the solution in Cos_Sim (X, Y) expression.Product both is greater than 1-δ, and the weight vectors of the kind child node that expression is selected will approach constraint constant vector as far as possible, to reach transmission requirement.

In numbering 0, select downloading data p _kThe weighting function of kind child node be

Be defined as follows:

This equation represents to choose u _iBe kind of a child node downloading data bag p _kArrive destination node u in time T _jFailed probability.Wherein

Expression u _iBe kind of a child node downloading data bag p _kBy intermediate relay node v _rArrived destination node u before time T _jProbability.Studies show that before, the interval Encounter Time obeys index distribution between adjacent meet for twice between vehicle.λ _ijU _iAnd u _jThe rate parameter of interval Encounter Time exponential distribution.Therefore can obtain from seed u _sNode is through via node v _rDouble bounce arrives destination node u _dProbability be:

$P_{\mathrm{srd}}^{\left(k\right)}\left(T\right)=\frac{h_r^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{rd}}}{h_r^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{rd}}-g_s^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{sr}}}(1-e^{-g_s^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{sr}}T})+\frac{g_s^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{sr}}}{g_s^{\left(k\right)}{\text{\λ}}_{\mathrm{sr}}-h_r^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{rd}}}(1-e^{-h_r^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{rd}}T})$

Wherein

Be respectively packet p _kCan be by kind of a child node u in single meets _sWith via node v _rThe average probability of transmission, relevant with data volume waiting for transmission in the vehicle node buffer memory, cache information can be collected module 120 by the transmission situation and obtain.

Fig. 2 is that a kind of car self-organization network network that utilizes of the present invention reduces the flow chart of steps that 3G shares the method for data download.Fig. 3 is the timeliness schematic diagram of preferred embodiment of the present invention.Coordinate Fig. 2 and shown in Figure 3, a kind of car self-organization network network that utilizes of the present invention reduces the method that 3G shares the data download, is used for 3G, vehicle network hybrid network, comprises the steps:

Step 201, system initialization obtains data number, number that vehicle history is met information and needed download, and obtaining simultaneously needs the set of the vehicle of these data.

Step 202 determines that the multistage strategy needs the number of times of carrying out.

Step 203, the historical information of meeting based on vehicle, calculate download policy in conjunction with transmission requirement and current transmission situation, depict the optimization problem that 3G downloads, find the solution this optimization problem and make corresponding download and determine, the data of downloading by 3G are transferred to by vehicle network the vehicle node that needs these data again, and according to the execution number of times that step 202 is determined, repeat this step.

Step 204, before the last moment of the timeliness restricted T that arrives downloading request, all do not obtain the vehicle node of data and download corresponding data by 3G.

Fig. 4 is that a kind of car self-organization network network that utilizes of the present invention reduces the flow chart of steps that 3G shares the preferred embodiment of the method that data download.Below will coordinate Fig. 4 to further illustrate step 203, in step 203, the step in each stage is as follows:

3.1 collect the transmission situation: comprise the number that needs the packet that transmits in the buffer memory of each vehicle node, the information such as packet of transmission success.

3.2 transmission situation and the vehicle node local cache information of the current network of collecting by step 0 are upgraded the weight of to be selected kind of child node.

3.3 download problem is formulated for optimization problem, and target is to minimize the data volume of downloading by 3G, constraint is the data that each vehicle node will be obtained before time-constrain needs download, finds the solution this optimization problem by greedy algorithm, obtains approximate optimal solution.

3.4 utilize the transmittability of vehicle self-organizing network, use the double bounce transmission that data are transmitted in vehicle network.

Optimization problem in step 0 is:

Minimize: $\underset{u_i\∈U}{\mathrm{\Σ}}\underset{p_k\∈P}{\mathrm{\Σ}}{X}_i^{\left(k\right)}$

Be constrained in: $\frac{\left|\right|W_{\mathrm{avg}}\left(k\right)\left(T\right)\left|\right|}{\left|\right|W_c\left|\right|}\·\mathrm{Cos}\_\mathrm{Sim}(W_{\mathrm{avg}}\left(k\right)\left(T\right),W_c)\≥1-\mathrm{\δ}$

W _c＝{ε，ε，ε，...}

(1) meter for vehicle in vehicle network is shown a set V={v ₁, v ₂, v ₃..., v _n, wherein V son is gathered U={u ₁, u ₂, u ₃..., u _mFor needing the vehicle identifiers of downloading data bag, set P={p ₁, p ₂..., p _kPacket that need to download of representative.

Expression vehicle u _iDownloading data p _kVector $W^{\left(k\right)}\left(T\right){=}_{u_j\∈U}(\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{i1}^{\left(k\right)}T,...,\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{\mathrm{ij}}^{\left(k\right)}T)$ Represent wherein set expression.For packet p _k, select by through electing the vehicle S set of data kind child node as ^(k), packet p _kArrive the weight of each destination node, wherein $W_{\mathrm{avg}}^{\left(k\right)}\left(T\right)=\frac{1}{\left|P\right|}\underset{k\∈P}{\mathrm{\Σ}}{W}^{\left(k\right)}\left(T\right).$ Expression is for all data that need to download, the mean value of seed node weights to be selected.

(2) each w in weight vectors W _ij ^(k)(T) u is chosen in expression _iFor kind of a child node downloading data bag pk arrived destination node u before data age T _jWeight.

(3) vectorial W _cBe the constant vector, can determine that the transmission requirement that will reach, ε are generally less than 1 and very little numerical value by the value that changes ε.

(4) The Length Ratio of expression weight vectors and constrained vector, the cosine similarity of two vectors is found the solution in Cos_Sim (X, Y) expression.Product both is greater than 1-δ, and the weight vectors of the kind child node that expression is selected will approach constraint constant vector as far as possible, to reach transmission requirement.

In numbering 0, select downloading data p _kThe weighting function of kind child node be

Be defined as follows:

This equation represents to choose u _iBe kind of a child node downloading data bag p _kArrive destination node u in time T _jFailed probability.Wherein

Expression u _iBe kind of a child node downloading data bag p _kBy intermediate relay node v _rArrived destination node u before time T _jProbability.Studies show that before, the interval Encounter Time obeys index distribution between adjacent meet for twice between vehicle.λ _ijU _iAnd u _jThe rate parameter of interval Encounter Time exponential distribution.Therefore can obtain from seed u _sNode is through via node v _rDouble bounce arrives destination node u _dProbability be:

$P_{\mathrm{srd}}^{\left(k\right)}\left(T\right)=\frac{h_r^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{rd}}}{h_r^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{rd}}-g_s^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{sr}}}(1-e^{-g_s^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{sr}}T})+\frac{g_s^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{sr}}}{g_s^{\left(k\right)}{\text{\λ}}_{\mathrm{sr}}-h_r^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{rd}}}(1-e^{-h_r^{\left(k\right)}{\mathrm{\λ}}_{\mathrm{rd}}T})$

Wherein Be respectively packet p _kCan be by kind of a child node u in single meets _sWith via node v _rThe average probability of transmission, relevant with data volume waiting for transmission in the vehicle node buffer memory, cache information can obtain by step 3.1.

Before each decision phase begins, need to upgrade according to the network information of the transmission situation of previous stage and current time the weight of to be selected kind of child node.Separate this optimization problem and can use greedy algorithm, obtain approximate optimal solution.

In sum, the present invention is a kind of to be utilized the car self-organization network network to reduce 3G to share method and system that data download based on the history of the vehicle information of meeting, by choosing the kind child node that is conducive to the vehicle network transmission most, the transmittability that takes full advantage of vehicle network is given data packet delivery the destination node that needs this packet, utilize the car self-organization network network, reach and both satisfy transmission requirement, reduce again the application target of 3G download.

Compared with prior art, the present invention has the following advantages:

1. assist the 3G network of high expense to download by the vehicle network transmittability of low expense, reach the purpose that reduces the user cost expense.

2. use multistage decision thought, can be in conjunction with current transmission situation in decision-making repeatedly, make downloading more accurately and determine, reduce the expense that 3G uses.

3. utilize the information of meeting of vehicle history, can effectively formulate download policy, take full advantage of the transmittability of vehicle network.

Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not is used for restriction the present invention.Any those skilled in the art all can under spirit of the present invention and category, modify and change above-described embodiment.Therefore, the scope of the present invention should be as listed in claims.

Claims (10)

1. one kind is utilized the car self-organization network network to reduce the system that 3G shares the data download, comprises at least:

The initialization module is used for system initialization, obtains the data message that vehicle history is met information and needed download, and obtaining simultaneously needs the set of the vehicle of these data;

Carry out number of times and determine module, be used for determining that the multistage strategy needs the number of times of carrying out;

Module is calculated and processed to download policy, according to the execution number of times of determining, be repeated below process: the historical information of meeting based on vehicle, calculate download policy in conjunction with transmission requirement and current transmission situation, depict the optimization problem that 3G downloads, find the solution this optimization problem and make corresponding download decision, the data of downloading by 3G are transferred to by vehicle network the vehicle node that needs these data again; And

3G downloads module, and the vehicle node that makes all not obtain data is downloaded corresponding data by 3G network.

2. the car self-organization network network that utilizes as claimed in claim 1 reduces the system that 3G shares the data download, it is characterized in that, this download policy is calculated and processed module and also comprises:

The transmission situation is collected module, is used for collecting the transmission situation;

Weight is upgraded module, according to transmission situation and the vehicle node local cache information of the current network of collecting, upgrades the weight of to be selected kind of child node;

Optimization problem is portrayed module, download problem is formulated for optimization problem, and target is to minimize the data volume of downloading by 3G, and constraint is the data that each vehicle node will be obtained before time-constrain needs download, and find the solution this optimization problem, obtain approximate optimal solution;

The transfer of data module utilizes the transmittability of car self-organization network network, uses the double bounce transmission that data are transmitted in vehicle network.

3. as claimed in claim 2ly utilize the car self-organization network network to reduce 3G to share the system that data are downloaded, it is characterized in that: this transmission situation comprises the number that needs the packet that transmits in the buffer memory of each vehicle node and the packet of transmission success.

4. the car self-organization network network that utilizes as claimed in claim 2 reduces the system that 3G shares the data download, it is characterized in that, this optimization problem is portrayed module and in the following way download problem is formulated for optimization problem:

Minimize: $\underset{u_i\∈U}{\mathrm{\Σ}}\underset{p_k\∈P}{\mathrm{\Σ}}{X}_i^{\left(k\right)}$

Be constrained in: $\frac{\left|\right|W_{\mathrm{avg}}\left(k\right)\left(T\right)\left|\right|}{\left|\right|W_c\left|\right|}\·\mathrm{Cos}\_\mathrm{Sim}(W_{\mathrm{avg}}\left(k\right)\left(T\right),W_c)\≥1-\mathrm{\δ}$

W _c＝{ε，ε，ε，...}

Meter for vehicle in vehicle network is shown a set V={v ₁, v ₂, v ₃..., v _n, wherein V son is gathered U={u ₁, u ₂, u ₃..., u _mFor needing the vehicle identifiers of downloading data bag, set P={p ₁, p ₂..., p _kPacket that need to download of representative,

Expression vehicle u _iDownloading data p _k, vector $W^{\left(k\right)}\left(T\right){=}_{u_j\∈U}(\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{i1}^{\left(k\right)}T,...,\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{\mathrm{ij}}^{\left(k\right)}T),$ $W_{\mathrm{avg}}^{\left(k\right)}\left(T\right)=\frac{1}{\left|P\right|}\underset{k\∈P}{\mathrm{\Σ}}{W}^{\left(k\right)}\left(T\right).$

5. the car self-organization network network that utilizes as claimed in claim 2 reduces the system that 3G shares the data download, and it is characterized in that: this optimization problem is portrayed module and found the solution this optimization problem by greedy algorithm.

6. one kind is utilized the car self-organization network network to reduce the method that 3G shares the data download, comprises the steps:

Step 1, system initialization obtains the data message that vehicle history is met information and needed download, and obtaining simultaneously needs the set of the vehicle of these data;

Step 2 determines that the multistage strategy needs the number of times of carrying out;

Step 3, the historical information of meeting based on vehicle, calculate download policy in conjunction with transmission requirement and current transmission situation, depict the optimization problem that 3G downloads, find the solution this optimization problem and make corresponding download and determine, the data of downloading by 3G are transferred to by vehicle network the vehicle node that needs these data again, and according to the execution number of times that step 2 is determined, repeat this step; And

Step 4, all do not obtain the vehicle node of data and download corresponding data by 3G.

7. a kind of car self-organization network network that utilizes as claimed in claim 6 reduces the method that 3G shares the data download, it is characterized in that, step 3 also comprises the steps:

Collect the transmission situation;

According to transmission situation and the vehicle node local cache information of the current network of collecting, upgrade the weight of to be selected kind of child node;

Download problem is formulated for optimization problem, and target is to minimize the data volume of downloading by 3G, and constraint is the data that each vehicle node will be obtained before time-constrain needs download, and finds the solution this optimization problem, obtains approximate optimal solution; And

Utilize the transmittability of vehicle self-organizing network, use the double bounce transmission that data are transmitted in vehicle network.

8. as claimed in claim 7ly a kind ofly utilize the car self-organization network network to reduce 3G to share the method that data are downloaded, it is characterized in that: the transmission situation of this collections transmission situation collection comprises the number that needs the packet that transmits in the buffer memory of each vehicle node and the packet of transmission success.

9. a kind of car self-organization network network that utilizes as claimed in claim 8 reduces the method that 3G shares the data download, it is characterized in that, this is formulated for the optimization problem step with download problem and in the following way download problem is formulated for optimization problem,

Minimize: $\underset{u_i\∈U}{\mathrm{\Σ}}\underset{p_k\∈P}{\mathrm{\Σ}}{X}_i^{\left(k\right)}$

Be constrained in: $\frac{\left|\right|W_{\mathrm{avg}}\left(k\right)\left(T\right)\left|\right|}{\left|\right|W_c\left|\right|}\·\mathrm{Cos}\_\mathrm{Sim}(W_{\mathrm{avg}}\left(k\right)\left(T\right),W_c)\≥1-\mathrm{\δ}$

W _c＝{ε，ε，ε，...}

Meter for vehicle in vehicle network is shown a set V={v ₁, v ₂, v ₃..., v _n, wherein V son is gathered U={u ₁, u ₂, u ₃..., u _mFor needing the vehicle identifiers of downloading data bag, set P={p ₁, p ₂..., p _kPacket that need to download of representative,

Expression vehicle u _iDownloading data p _k, vector $W^{\left(k\right)}\left(T\right){=}_{u_j\∈U}(\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{i1}^{\left(k\right)}T,...,\underset{u_i\∈S^{\left(k\right)}}{\mathrm{\Π}}{W}_{\mathrm{ij}}^{\left(k\right)}T),$ $W_{\mathrm{avg}}^{\left(k\right)}\left(T\right)=\frac{1}{\left|P\right|}\underset{k\∈P}{\mathrm{\Σ}}{W}^{\left(k\right)}\left(T\right).$

10. the car self-organization network network that utilizes as claimed in claim 9 reduces the system that 3G shares the data download, it is characterized in that: utilize greedy algorithm to find the solution this optimization problem in step 3.

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