CN103379575A - Vehicular network routing protocol utilizing intersection static nodes to assist with data forwarding - Google Patents

Abstract

The invention discloses a vehicular network routing protocol utilizing intersection static nodes to assist with data forwarding. The static nodes are arranged on all the intersections and collect and process UPAC messages continuously, and then the road section transmission delay tdelay and the road section communication state tstate can be obtained. The static nodes and all the nodes of vehicle nodes collect and process HELLO messages continuously, and then the failure time point TD can be obtained. When data are forwarded in the road sections, the failure time point TD and the microcosmic greedy forwarding algorithm are utilized by the routing protocol for selecting the next-hop node for data forwarding. When the data are forwarded to the intersections, the road section transmission delay tdelay, the road section communication state tstate and the macroscopic greedy forwarding algorithm are utilized by the routing protocol for selecting the next forwarding road section for data forwarding. The vehicular network routing protocol has the advantages that system overhead is small, implementation of the algorithms is simple, the expansibility is good, time delay is low and the transfer rate is high.

Description

A kind of vehicle-mounted network routing protocol that utilizes crossing static node auxiliary data to transmit

Technical field

The present invention relates to the vehicular ad hoc network technology, be specifically related to the vehicle-mounted network routing protocol that utilizes crossing static node auxiliary data to transmit.

Background technology

Along with the development of intelligent transportation system, the multi-hop transmission of carrying out mass data in the vehicular ad hoc network of urban transportation more and more causes people's concern.The movement that is different from node in traditional mobile ad hoc network is random, and the movement of node has track in the vehicular ad hoc network of urban transportation.Data are transmitted between vehicle node, and the motion track of vehicle node is to be represented by a series of crossings and the highway section that is attached thereto, so when data during at the highway section repeating, transmit track along the highway section, when data retransmission arrived the crossing, the vehicular ad hoc network Routing Protocol can select the next highway section of transmitting carry out the forwarding of data by its algorithm, and then data are transmitted along the highway section again, the process of transmitting constantly repeats these steps, until run into destination node.In the present vehicular ad hoc network Routing Protocol, some vehicular ad hoc network Routing Protocol is to be in the crossing by the data that algorithm is judged forwarding, although do not need extras, algorithm is complicated, and overhead is large, and accuracy is not high yet.And utilize the crossing static node to judge that the data of transmitting are in the crossing (when data retransmission during to the crossing static node, illustrate that the data of transmitting are in the crossing), and be that the next routing policy of transmitting the highway section of data selection of transmitting is the research direction that instantly has potentiality.The key problem in technology of this routing policy is to select the next highway section of transmitting according to the connected state in highway section, thereby reduces time delay or improve transmissibility.The method of current employing has: (1) transmits the foundation in highway section according to the historical information of highway section connected state as the selection next one.(2) mode by multi-hop broadcasting obtains the current connected state information in highway section, and in order to obtain the global optimum path, also constantly carries out information interchange between static node.Wherein, method (1) can't be learned the connected state that the highway section is current exactly, and the next one forwarding highway section that obtains by historical information may not be optimal selection.Information interchange between the internodal multi-hop broadcasting of each in the method (2) and static node has increased the weight of offered load, and algorithm is complicated.

Summary of the invention

The object of the invention is to overcome the deficiency of existing vehicle-mounted network routing agreement, provide a kind of performance the more excellent vehicle-mounted network routing protocol that utilizes crossing static node auxiliary data to transmit, realize the multi-hop transmission of mass data.The present invention obtains the highway section propagation delay time t in each highway section be attached thereto by the crossing static node _DelayWith highway section connected state t _State, utilize these two information and greedy forwarding algorithm to select the next highway section of transmitting, information is easy, value is high, and algorithm is realized simply, cost is low, and the selected next highway section of transmitting is connective strong; Simultaneously because the existence of static node, so that it is more excellent to carry out the greedy forwarding algorithm that data retransmission adopts in the highway section, basically avoided the generation of local optimum phenomenon.The Routing Protocol that utilizes crossing static node auxiliary data to transmit after the improvement has improved the success rate that data are transmitted, and reduces time delay and offered load.Concrete technical scheme of the present invention is as follows.

A kind of vehicle-mounted network routing protocol that utilizes crossing static node auxiliary data to transmit, it comprises the steps:

(1) at each place, crossing static node is set, all static nodes are constantly collected the UPAC message and are processed, and obtain highway section propagation delay time t _DelayWith highway section connected state t _StateAll nodes that comprise static node and vehicle node are constantly collected the HELLO message and are processed acquisition out-of-service time point TD.

(2) when data during at the highway section repeating, Routing Protocol utilizes out-of-service time point TD and the greedy forwarding algorithm of microcosmic to select next-hop node to carry out data retransmission; When data retransmission arrived the intersection, Routing Protocol utilized highway section propagation delay time t _Delay, highway section connected state t _StateSelect the next highway section of transmitting to carry out data retransmission with the greedy forwarding algorithm of macroscopic view.

In the above-mentioned agreement, all static nodes in the step (1) are constantly collected the UPAC message and are processed, and obtain highway section propagation delay time t _DelayWith highway section connected state t _StateDetailed process be:

Each static node periodically sends connective unicast message UPAC to its all adjacent static node, cycle is T1, and the UPAC message comprises source static node IP address, purpose static node IP address, purpose static node geographical position, message transmitting time.Described adjacent static node refers to the static node of the other end in each highway section that is connected with this static node.After vehicle on the highway section receives the UPAC message, utilize the geographical position of purpose static node, select to carry out the forwarding of message as down hop from the nearest neighbor node of purpose static node in the neighbor node tabulation.If vehicle node is at time t _WaitIn still can't find correct down hop, then directly abandon this message.Through the repeatedly transfer of vehicle node, the purpose static node receives the UPAC message of adjacent static node;

Each static node is safeguarded an adjacent static node tabulation, the highway section propagation delay time t in IP address, geographical position and this highway section of the static node of each highway section other end that the tabulation preservation is connected with this crossing _Delay, highway section connected state t _StateThe corresponding highway section of list item;

After static node receives the UPAC message, deduct the message transmitting time that is kept in the UPAC message by the current time and obtain the UPAC message is delivered to the purpose static node from the source static node time delay, and be equivalent to data and be transferred to the time delay of the static node that sends the UPAC message from the static node that receives the UPAC message through corresponding road section, time delay is filled or is covered the highway section propagation delay time t of corresponding list item in the adjacent static node tabulation _Delay, finish highway section propagation delay time t _DelayInitialization or renewal.This time delay is used for information relatively when being the next forwarding of macroscopical greedy forwarding algorithm selection highway section, reflection is to the dense degree of vehicle in should the highway section of time delay, highway section vehicle closeness is higher, the time delay that data are transmitted in this highway section is shorter, so whether the meaning of this delay data does not lie in accurate, so equivalence is rational;

The highway section connected state t of each list item in the adjacent static node tabulation of static node _StateIt is an annular chain meter that is consisted of by 10 elements.When static node receives the UPAC message that a highway section other end static node that is attached thereto sends, then time of advent of this UPAC message is filled in corresponding list item highway section connected state t _StateThe annular chain meter element in, after having filled 10 elements, begin from linked list head the time of advent of the UPAC message that then will then receive, and covers successively, realize to upgrade.When the greedy forwarding algorithm of macroscopic view is selected next forwarding highway section, then with each list item highway section connected state t _StateAnnular chain meter in the nearest time deduct the farthest time, obtain time difference.The time difference of certain list item gained is less, illustrates that the connected state of this list item corresponding road section is better.Receive 10 UPAC messages because be equally, the vehicle closeness is lower, in the highway section of poor connectivity, the UPAC message is lost easily, thereby make time difference longer, otherwise, in higher, the connective strong highway section of vehicle closeness, the UPAC message is difficult for losing, and static node can receive the UPAC message of same quantity within the shorter time.

In the above-mentioned agreement, specifically the comprising of the greedy forwarding algorithm of microcosmic in the step (2):

(2.1) when source node plans to send data to the purpose static node, then obtain the geographical position of the static node of more close purpose static node in the geographical position of purpose static node and the highway section, source node place by grid location service GLS;

(2.2) data encapsulation that the first step, source node will send to the purpose static node becomes common IP packet; Second step, whole IP packet is carried out the encapsulation second time, for the second time in the IP packet after the encapsulation, the destination node IP address of header part is the IP address by the static node of more close purpose static node in the highway section, source node place of GLS acquisition, and content part is the geographical position of the destination node after for the second time encapsulation and the whole IP packet in the first step; In the 3rd step, marking this packet is the IP packet; In the 4th step, the geographical position of the destination node after for the second time encapsulation of utilization is selected to carry out the forwarding of IP packet as down hop from the nearest neighbor node of this destination node in the neighbor node tabulation;

When (2.3) being in vehicle node in the highway section and receiving the IP packet, check that at first whether having static node and this static node in the neighbor node tabulation is the destination node of the IP packet that receives, if so, then directly give this static node with the IP data packet delivery; If not having static node or static node in the neighbor node tabulation is not destination node, vehicle node is then utilized the geographical position of destination node, selects to carry out the forwarding of IP packet as down hop from the nearest neighbor node of destination node in the neighbor node tabulation; If vehicle node is at time t _WaitIn still can't find correct down hop, then directly abandon this IP packet;

(2.4) when static node receives the IP packet, at first it is carried out the decapsulation first time, thereby obtain the IP address of real destination node, if the IP address is exactly the IP address of this static node, this static node then directly receives this IP packet; If the IP address is not the IP address of this static node, then this static node at first utilizes macroscopical greedy forwarding algorithm to select the next highway section of transmitting, then whole IP packet is carried out Reseal, in the IP packet behind the Reseal, the destination node IP address of header part is to utilize the selected next IP address of transmitting the static node of the highway section other end of macroscopical greedy forwarding algorithm, and content part is the geographical position of the destination node behind the Reseal and the whole IP packet when carrying out for the first time decapsulation; Utilize at last the geographical position of the destination node behind the Reseal, select to carry out the forwarding of IP packet as down hop from the nearest neighbor node of this destination node in the neighbor node tabulation.

Wherein, utilize the geographical position of destination node, the detailed process of selecting to carry out data retransmission from the nearest neighbor node of destination node as down hop in the neighbor node tabulation is, node at first sorts as foundation with out-of-service time point TD to the neighbor node tabulation, then sequentially each list item in the neighbor node tabulation is calculated, to deduct exactly the out-of-service time point TD of each list item the current time, when the result of calculation of certain list item is negative value, illustrate that this list item lost efficacy, corresponding neighbor node has left the maximum effective communication distance R of this node _Max, when the result of calculation of certain list item be on the occasion of, illustrate that neighbor node corresponding to this list item still is in the communication range of this node.Because be as sort by, so down neighbor node corresponding to all list items also is in the communication range of this node again with out-of-service time point TD.At last, node is selected from the nearest neighbor node of destination node to carry out the forwarding of data as down hop in remaining neighbor node.

In the above-mentioned agreement, the concrete steps of the macroscopical greedy forwarding algorithm in the step (2.4) are:

The concrete steps of the macroscopical greedy forwarding algorithm in the step (2.4) are as follows.

The highway section connected state t of each list item during (2.4.1) static node is at first tabulated according to adjacent static node _StateCalculate time difference corresponding to each list item.Described time difference is by with connected state t in highway section in the list item _StateAnnular chain meter nearest time of preserving deduct that time farthest obtains.This time difference corresponding when some list items surpasses threshold value T _ThreadThe time, represent that highway section corresponding to this list item is in the state of poor connectivity, then the highway section of correspondence is got rid of outside the range of choice of selecting next forwarding highway section.If the corresponding road section of all list items all is in the state of poor connectivity, then select the highway section that wherein connectedness is the strongest to carry out the forwarding of IP packet as next one forwarding highway section.If not to vehicle node that should the highway section, then select the suboptimum highway section in the neighbor node of the static node tabulation, the rest may be inferred.

(2.4.2) got rid of the highway section of poor connectivity after, static node is at first according to highway section propagation delay time t _DelayCalculate the data transmission distance D of each remaining in the tabulation of neighbours' static node list item _Trans, then select D _TransMinimum corresponding road section is transmitted the highway section as the next one and is carried out the forwarding of IP packet; If not to vehicle node that should the highway section, then select the suboptimum highway section in the neighbor node of the static node tabulation, the rest may be inferred.

Wherein, according to highway section propagation delay time t _DelayCalculated data transmission range D _TransParticular content be that establishing data transmission bauds is v _Trans, with v _TransWith the tabulate highway section propagation delay time t of some list items of adjacent static node _DelayMultiply each other, obtain the time delay distance D of corresponding road section _DelayDescribed time delay distance D _DelayThe expression data are transferred to the required pseudo range of corresponding road section other end static node from this static node, but not real geographic distance; In higher, the connective strong highway section of vehicle closeness, the time delay weak point that the transmission of data is required, time delay distance D _DelayLittle and geographic distance is not necessarily little, on the contrary the vehicle closeness is lower, in the highway section of poor connectivity, the transmission of data required the time prolong time delay distance D _DelayLarge and geographic distance is not necessarily large; Described data transmission bauds v _TransComputing formula as follows:

$v_{\mathrm{trans}}=\frac{R}{t_{\mathrm{trans}}}$

Wherein R represents the average effective communication distance of vehicle node and static node, and t _TransExpression node processing data, transmission data, data one-hop propagation, next-hop node receive the required time of data.

Data are transferred to the time delay distance D of the static node of a highway section other end that is attached thereto from current static node _DelaySelect this highway section as the next one to transmit highway section when carrying out data retransmission, the transmission range D of current static node and purpose static node to the geometric distance L of purpose static node with having consisted of with this highway section other end static node _Trans, specific formula for calculation is as follows:

D _trans=D _delay+L

In the above-mentioned agreement, all nodes that comprise static node and vehicle node in the step (1) are constantly collected the HELLO message and are processed, the detailed process that obtains out-of-service time point TD is, each node periodically carries out one of HELLO message and jumps broadcasting, message comprises IP address, geographical position, moving direction, the translational speed of node self, and the cycle is T ₂If static node, then the moving direction of this static node and translational speed are 0.

IP address, geographical position, moving direction, translational speed and the out-of-service time point TD of neighbor node preserved in neighbor node tabulation of each node maintenance, neighbor node tabulation.The corresponding neighbor node of list item.

When node receives the HELLO message, at first judge whether to exist the list item corresponding with the node of this HELLO message of broadcasting, if there is no, then create list item that should node, node IP address in the HELLO message, geographical position correspondingly are filled into this list item corresponding neighbor node IP address, geographical position, and calculate the out-of-service time according to the geographical position in the HELLO message, moving direction, translational speed and put TD, finish initialization.If exist, then the node IP address in the HELLO message, geographical position are correspondingly covered this list item corresponding neighbor node IP address, geographical position, and calculate the out-of-service time according to the geographical position in the HELLO message, moving direction, translational speed and put TD, finish renewal.Wherein, the step of calculating out-of-service time point TD is, at first calculates this neighbor node according to the geographical position in the HELLO message, moving direction, translational speed and rests on time of staying TL in this node communication range; Secondly the out-of-service time that TL and current time TN addition is obtained this neighbor node put TD(namely this neighbor node leave time point in this node communication range).The computing formula of wherein said time of staying TL is as follows:

$\mathrm{TL}=\frac{({\mathrm{YV}}_V-{\mathrm{XV}}_H)\±\sqrt{({V_H}^2+{V_V}^2)R_{\max }^2-{({\mathrm{XV}}_V+V_{H}Y)}^2}}{{V_H}^2+{V_V}^2}$

X=x wherein _u-x _d, V _H=v _uCos θ _u-v _dCos θ _d, Y=y _u-y _d, V _V=v _uSin θ _u-v _dSin θ _d, TL is the time of staying of neighbor node, also claims the link prediction life span, (x _u, y _u), (x _d, y _d) be respectively two positions that node is current, (v _u, θ _u), (v _d, θ _d) be respectively translational speed and the moving direction of two nodes, R _MaxBe internodal maximum effective communication distance.

Compared with prior art, advantage of the present invention and good effect are:

1, the present invention obtains the highway section propagation delay time t in each highway section be attached thereto by the crossing static node _DelayWith highway section connected state t _State, utilize these two information and greedy forwarding algorithm to select the next highway section of transmitting, information is easy, value is high, and algorithm is realized simply, cost is low, and the selected next highway section of transmitting is connective strong.

2, because the existence of static node, so that it is more excellent to carry out the greedy forwarding algorithm that data retransmission adopts in the highway section, basically avoided the generation of local optimum phenomenon.

3, the Routing Protocol that utilizes crossing static node auxiliary data to transmit after the improvement has improved the success rate that data are transmitted, and reduces time delay and offered load.

Description of drawings

Fig. 1 is the overall schematic in the embodiment of the present invention.

Fig. 2 a is the form schematic diagram of UPAC message in the embodiment of the present invention; Fig. 2 b is the form schematic diagram of adjacent static node tabulation; Fig. 2 c is the highway section connected state t of adjacent static node tabulation _StateThe preserving type schematic diagram; Fig. 2 d is the form schematic diagram of HELLO message; Fig. 2 e is the form schematic diagram of neighbor node tabulation.

Fig. 3 is the greedy forwarding algorithm flow chart of the microcosmic in the embodiment of the present invention.

Fig. 4 is the greedy forwarding algorithm schematic diagram of the microcosmic in the embodiment of the present invention.

Fig. 5 is the macroscopical greedy forwarding algorithm flow chart in the embodiment of the present invention.

Fig. 6 is the macroscopical greedy forwarding algorithm schematic diagram in the embodiment of the present invention.

Embodiment

Below in conjunction with accompanying drawing the specific embodiment of the present invention is described further.

Fig. 1 is overall schematic of the present invention, and concrete steps comprise that (1) arranges static node at each place, crossing, and all static nodes are constantly collected the UPAC message and processed, and obtain highway section propagation delay time t _DelayWith highway section connected state t _StateAll nodes that comprise static node and vehicle node are constantly collected the HELLO message and are processed acquisition out-of-service time point TD.(2) when data during at the highway section repeating, Routing Protocol utilizes out-of-service time point TD and the greedy forwarding algorithm of microcosmic to select next-hop node to carry out data retransmission; When data retransmission arrived the intersection, Routing Protocol utilized highway section propagation delay time t _Delay, highway section connected state t _StateSelect the next highway section of transmitting to carry out data retransmission with the greedy forwarding algorithm of macroscopic view.

All static nodes in the step (1) are constantly collected the UPAC message and are processed, and obtain highway section propagation delay time t _DelayWith highway section connected state t _StateDetailed process be, each static node periodically sends connective unicast message UPAC to its all adjacent static node, cycle is T1, and the UPAC message comprises source static node IP address, purpose static node IP address, purpose static node geographical position, message transmitting time.Fig. 2 a is the form schematic diagram of UPAC message.Described adjacent static node refers to the static node of the other end in each highway section that is connected with this static node.After vehicle on the highway section receives the UPAC message, utilize the geographical position of purpose static node, select to carry out the forwarding of message as down hop from the nearest neighbor node of purpose static node in the neighbor node tabulation.If vehicle node is at time t _WaitIn still can't find correct down hop, then directly abandon this message.Through the repeatedly transfer of vehicle node, the purpose static node receives the UPAC message of adjacent static node.

Each static node is safeguarded an adjacent static node tabulation, the highway section propagation delay time t in IP address, geographical position and this highway section of the static node of each highway section other end that the tabulation preservation is connected with this crossing _Delay, highway section connected state t _StateThe corresponding highway section of list item.Fig. 2 b is the form schematic diagram of the adjacent static node tabulation safeguarded of each static node, has wherein only listed three static nodes.

After static node receives the UPAC message, deduct the message transmitting time that is kept in the UPAC message by the current time and obtain the UPAC message is delivered to the purpose static node from the source static node time delay, and be equivalent to data and be transferred to the time delay of the static node that sends the UPAC message from the static node that receives the UPAC message through corresponding road section, time delay is filled or is covered the highway section propagation delay time t of corresponding list item in the adjacent static node tabulation _Delay, finish highway section propagation delay time t _DelayInitialization or renewal.This time delay is used for information relatively when being the next forwarding of macroscopical greedy forwarding algorithm selection highway section, reflection is to the dense degree of vehicle in should the highway section of time delay, highway section vehicle closeness is higher, the time delay that data are transmitted in this highway section is shorter, so whether the meaning of this delay data does not lie in accurate, so equivalence is rational.

The highway section connected state t of each list item in the adjacent static node tabulation of static node _StateBe an annular chain meter that is made of 10 elements, the schematic diagram of its preserving type is shown in Fig. 2 c.When static node receives the UPAC message that a highway section other end static node that is attached thereto sends, then time of advent of this UPAC message is filled in corresponding list item highway section connected state t _StateThe annular chain meter element in, after having filled 10 elements, begin from linked list head the time of advent of the UPAC message that then will then receive, and covers successively, realize to upgrade.When the greedy forwarding algorithm of macroscopic view is selected next forwarding highway section, then with each list item highway section connected state t _StateAnnular chain meter in the nearest time deduct the farthest time, obtain time difference.The time difference of certain list item gained is less, illustrates that the connected state of this list item corresponding road section is better.Receive 10 UPAC messages because be equally, the vehicle closeness is lower, in the highway section of poor connectivity, the UPAC message is lost easily, thereby make time difference longer, otherwise, in higher, the connective strong highway section of vehicle closeness, the UPAC message is difficult for losing, and static node can receive the UPAC message of same quantity within the shorter time.

All nodes that comprise static node and vehicle node in the step (1) are constantly collected the HELLO message and are processed, the detailed process that obtains out-of-service time point TD is, each node periodically carries out one of HELLO message and jumps broadcasting, message comprises IP address, geographical position, moving direction, the translational speed of node self, and the cycle is T ₂Form is shown in Fig. 2 d.If static node, then the moving direction of this static node and translational speed are 0.

IP address, geographical position, moving direction, translational speed and the out-of-service time point TD of neighbor node preserved in neighbor node tabulation of each node maintenance, neighbor node tabulation.The corresponding neighbor node of list item.Fig. 2 e is the form schematic diagram of the neighbor node tabulation safeguarded of each node, wherein only lists three neighbor nodes.

When node receives the HELLO message, at first judge whether to exist the list item corresponding with the node of this HELLO message of broadcasting, if there is no, then create list item that should node, node IP address in the HELLO message, geographical position correspondingly are filled into this list item corresponding neighbor node IP address, geographical position, and calculate the out-of-service time according to the geographical position in the HELLO message, moving direction, translational speed and put TD, finish initialization.If exist, then the node IP address in the HELLO message, geographical position are correspondingly covered this list item corresponding neighbor node IP address, geographical position, and calculate the out-of-service time according to the geographical position in the HELLO message, moving direction, translational speed and put TD, finish renewal.Wherein, the step of calculating out-of-service time point TD is, at first calculates this neighbor node according to the geographical position in the HELLO message, moving direction, translational speed and rests on time of staying TL in this node communication range; Secondly the out-of-service time that TL and current time TN addition is obtained this neighbor node put TD(namely this neighbor node leave time point in this node communication range).For example, current time TN is 21:30:30, and time of staying TL is 10s, and then the out-of-service time point is 21:30:40.The computing formula of wherein said time of staying TL is as follows:

$\mathrm{TL}=\frac{({\mathrm{YV}}_V-{\mathrm{XV}}_H)\±\sqrt{({V_H}^2+{V_V}^2)R_{\max }^2-{({\mathrm{XV}}_V+V_{H}Y)}^2}}{{V_H}^2+{V_V}^2}$

X=x wherein _u-x _d, V _H=v _uCos θ _u-v _dCos θ _d, Y=y _u-y _d, V _V=v _uSin θ _u-v _dSin θ _d, TL is the time of staying of neighbor node, also claims the link prediction life span, (x _u, y _u), (x _d, y _d) be respectively two positions that node is current, (v _u, θ _u), (v _d, θ _d) be respectively translational speed and the moving direction of two nodes, R _MaxBe internodal maximum effective communication distance.

The concrete steps of the greedy forwarding algorithm of the microcosmic in the step (2) are as follows, and flow chart as shown in Figure 3.

(2.1) when source node plans to send data to the purpose static node, then obtain the geographical position of the static node of more close purpose static node in the geographical position of purpose static node and the highway section, source node place by grid location service GLS.

(2.2) data encapsulation that the first step, source node will send to the purpose static node becomes common IP packet.Second step, whole IP packet is carried out the encapsulation second time, for the second time in the IP packet after the encapsulation, the destination node IP address of header part is the IP address by the static node of more close purpose static node in the highway section, source node place of GLS acquisition, and content part is the geographical position of the destination node after for the second time encapsulation and the whole IP packet in the first step.In the 3rd step, marking this packet is the IP packet.In the 4th step, the geographical position of the destination node after for the second time encapsulation of utilization is selected to carry out the forwarding of IP packet as down hop from the nearest neighbor node of this destination node in the neighbor node tabulation.

When (2.3) being in vehicle node in the highway section and receiving the IP packet, check that at first whether having static node and this static node in the neighbor node tabulation is the destination node of the IP packet that receives, if so, then directly give this static node with the IP data packet delivery.If not having static node or static node in the neighbor node tabulation is not destination node, vehicle node is then utilized the geographical position of destination node, selects to carry out the forwarding of IP packet as down hop from the nearest neighbor node of destination node in the neighbor node tabulation.If vehicle node is at time t _WaitIn still can't find correct down hop, then directly abandon this IP packet.

(2.4) when static node receives the IP packet, at first it is carried out the decapsulation first time, thereby obtain the IP address of real destination node, if the IP address is exactly the IP address of this static node, this static node then directly receives this IP packet.If the IP address is not the IP address of this static node, then this static node at first utilizes macroscopical greedy forwarding algorithm to select the next highway section of transmitting, then whole IP packet is carried out Reseal, in the IP packet behind the Reseal, the destination node IP address of header part is to utilize the selected next IP address of transmitting the static node of the highway section other end of macroscopical greedy forwarding algorithm, and content part is the geographical position of the destination node behind the Reseal and the whole IP packet when carrying out for the first time decapsulation.Utilize at last the geographical position of the destination node behind the Reseal, select to carry out the forwarding of IP packet as down hop from the nearest neighbor node of this destination node in the neighbor node tabulation.

Wherein, utilize the geographical position of destination node, the detailed process of selecting to carry out data retransmission from the nearest neighbor node of destination node as down hop in the neighbor node tabulation is, node at first sorts as foundation with out-of-service time point TD to the neighbor node tabulation, then sequentially each list item in the neighbor node tabulation is calculated, to deduct exactly the out-of-service time point TD of each list item the current time, when the result of calculation of certain list item is negative value, illustrate that this list item lost efficacy, corresponding neighbor node has left the maximum effective communication distance R of this node _Max, when the result of calculation of certain list item be on the occasion of, illustrate that neighbor node corresponding to this list item still is in the communication range of this node.Because be as sort by, so down neighbor node corresponding to all list items also is in the communication range of this node again with out-of-service time point TD.At last, node is selected from the nearest neighbor node of destination node to carry out the forwarding of data as down hop in remaining neighbor node.

Fig. 4 is the object lesson that vehicle node is selected next-hop node.By collection and the processing to the HELLO message, have 6 list items in the tabulation of the neighbor node of vehicle node A.When IP packet that to receive a destination node be static node B, vehicle node A checks that at first whether having static node and this static node in the neighbor node tabulation is static node B, owing to do not exist, so vehicle node at first sorts as foundation with out-of-service time point TD to the neighbor node tabulation, then sequentially 6 list items in the neighbor node tabulation are calculated, will deduct exactly the out-of-service time point TD of each list item the current time.Wherein, although M1 is from the nearest neighbor node of destination node, because result of calculation is that negative value (illustrates that M1 has left the maximum effective communication distance R of this node _Max), so be excluded outside range of choice.M2 to the result of calculation of these 5 neighbor nodes of M5 be on the occasion of, still be in the communication range of vehicle node A.In these 5 neighbor nodes, M2 is from the nearest neighbor node of static node B, so vehicle node A selects neighbor node M2 as the next-hop node of data retransmission.

The concrete steps of the macroscopical greedy forwarding algorithm in the step (2.4) are as follows.Flow chart as shown in Figure 5.

The highway section connected state t of each list item during (2.4.1) static node is at first tabulated according to adjacent static node _StateCalculate time difference corresponding to each list item.Described time difference is by with connected state t in highway section in the list item _StateAnnular chain meter nearest time of preserving deduct that time farthest obtains.This time difference corresponding when some list items surpasses threshold value T _ThreadThe time, represent that highway section corresponding to this list item is in the state of poor connectivity, then the highway section of correspondence is got rid of outside the range of choice of selecting next forwarding highway section.If the corresponding road section of all list items all is in the state of poor connectivity, then select the highway section that wherein connectedness is the strongest to carry out the forwarding of IP packet as next one forwarding highway section.If not to vehicle node that should the highway section, then select the suboptimum highway section in the neighbor node of the static node tabulation, the rest may be inferred.

(2.4.2) got rid of the highway section of poor connectivity after, static node is at first according to highway section propagation delay time t _DelayCalculate the data transmission distance D of each remaining in the tabulation of neighbours' static node list item _Trans, then select D _TransMinimum corresponding road section is transmitted the highway section as the next one and is carried out the forwarding of IP packet; If not to vehicle node that should the highway section, then select the suboptimum highway section in the neighbor node of the static node tabulation, the rest may be inferred.

Wherein, according to highway section propagation delay time t _DelayCalculated data transmission range D _TransParticular content be that establishing data transmission bauds is v _Trans, with v _TransWith the tabulate highway section propagation delay time t of some list items of adjacent static node _DelayMultiply each other, obtain the time delay distance D of corresponding road section _DelayDescribed time delay distance D _DelayThe expression data are transferred to the required pseudo range of corresponding road section other end static node from this static node, but not real geographic distance; In higher, the connective strong highway section of vehicle closeness, the time delay weak point that the transmission of data is required, time delay distance D _DelayLittle and geographic distance is not necessarily little, on the contrary the vehicle closeness is lower, in the highway section of poor connectivity, the transmission of data required the time prolong time delay distance D _DelayLarge and geographic distance is not necessarily large; Described data transmission bauds v _TransComputing formula as follows:

$v_{\mathrm{trans}}=\frac{R}{t_{\mathrm{trans}}}$

Wherein R represents the average effective communication distance of vehicle node and static node, and t _TransExpression node processing data, transmission data, data one-hop propagation, next-hop node receive the required time of data.

Data are transferred to the time delay distance D of the static node of a highway section other end that is attached thereto from current static node _DelaySelect this highway section as the next one to transmit highway section when carrying out data retransmission, the transmission range D of current static node and purpose static node to the geometric distance L of purpose static node with having consisted of with this highway section other end static node _Trans, specific formula for calculation is as follows:

D _trans=D _delay+L

Fig. 6 is that static node is selected a next object lesson transmitting the highway section.Have 3 list items in the adjacent static node tabulation of static node A.At first, static node A is according to the highway section connected state t of each list item in the tabulation _StateCalculate time difference corresponding to each list item, be respectively t _State_ AB, t _State_ AE, t _State_ AF.Because t _State_ AF〉T _Thread, illustrate that highway section AF is in the state of poor connectivity, it is got rid of outside the range of choice of selecting next forwarding highway section.Then, static node A is according to highway section propagation delay time t _DelayCalculate the data transmission distance D of remaining 2 list items in the adjacent static node tabulation _Trans, because D _Trans_ AE＜D _Trans_ AB is so select highway section AE.At last, be not in the communication range of static node A because have vehicle node among the AE of highway section this moment, so static node A has selected suboptimum highway section AB to carry out data retransmission.

Claims (5)

1. a vehicle-mounted network routing protocol that utilizes crossing static node auxiliary data to transmit is characterized in that comprising the steps:

(1) at each place, crossing static node is set, all static nodes are constantly collected the UPAC message and are processed, and obtain highway section propagation delay time t _DelayWith highway section connected state t _StateAll nodes that comprise static node and vehicle node are constantly collected the HELLO message and are processed acquisition out-of-service time point TD;

(2) when data during at the highway section repeating, Routing Protocol utilizes out-of-service time point TD and the greedy forwarding algorithm of microcosmic to select next-hop node to carry out data retransmission; When data retransmission arrived the crossing, Routing Protocol utilized highway section propagation delay time t _Delay, highway section connected state t _StateSelect the next highway section of transmitting to carry out data retransmission with the greedy forwarding algorithm of macroscopic view.

2. a kind of vehicle-mounted network routing protocol that utilizes crossing static node auxiliary data to transmit according to claim 1 is characterized in that all static nodes in the step (1) are constantly collected the UPAC message and processed acquisition highway section propagation delay time t _DelayWith highway section connected state t _StateDetailed process be:

Each static node periodically sends connective unicast message UPAC to its all adjacent static node, and the cycle is T ₁, the UPAC message comprises source static node IP address, purpose static node IP address, purpose static node geographical position, message transmitting time; Described adjacent static node refers to the static node of the other end in each highway section that is connected with this static node; After vehicle on the highway section receives the UPAC message, utilize the geographical position of purpose static node, select to carry out the forwarding of message as down hop from the nearest neighbor node of purpose static node in the neighbor node tabulation; If vehicle node is at time t _WaitIn still can't find correct down hop, then directly abandon this message; Through the repeatedly transfer of vehicle node, the purpose static node receives the UPAC message of adjacent static node;

Each static node is safeguarded an adjacent static node tabulation, the highway section propagation delay time t in IP address, geographical position and this highway section of the static node of each highway section other end that the tabulation preservation is connected with this crossing _Delay, highway section connected state t _StateThe corresponding highway section of list item;

After static node receives the UPAC message, deduct the message transmitting time that is kept in the UPAC message by the current time and obtain the UPAC message is delivered to the purpose static node from the source static node time delay, and be equivalent to data and be transferred to the time delay of the static node that sends the UPAC message from the static node that receives the UPAC message through corresponding road section, time delay is filled or is covered the highway section propagation delay time t of corresponding list item in the adjacent static node tabulation _Delay, finish highway section propagation delay time t _DelayInitialization or renewal;

The highway section connected state t of each list item in the adjacent static node tabulation of static node _StateIt is an annular chain meter that is consisted of by 10 elements; When static node receives the UPAC message that a highway section other end static node that is attached thereto sends, then time of advent of this UPAC message is filled in corresponding list item highway section connected state t _StateThe annular chain meter element in, after having filled 10 elements, begin from linked list head the time of advent of the UPAC message that then will then receive, and covers successively, realize to upgrade; When the greedy forwarding algorithm of macroscopic view is selected next forwarding highway section, then with each list item highway section connected state t _StateAnnular chain meter in the nearest time deduct the farthest time, obtain time difference; The time difference of certain list item gained is less, illustrates that the connected state of this list item corresponding road section is better; Receive 10 UPAC messages because be equally, the vehicle closeness is lower, in the highway section of poor connectivity, the UPAC message is lost easily, thereby make time difference longer, otherwise, in higher, the connective strong highway section of vehicle closeness, the UPAC message is difficult for losing, and static node can receive the UPAC message of same quantity within the shorter time.

3. a kind of vehicle-mounted network routing protocol that utilizes crossing static node auxiliary data to transmit according to claim 1 is characterized in that specifically the comprising of the greedy forwarding algorithm of microcosmic in the step (2):

(2.1) when source node plans to send data to the purpose static node, then obtain the geographical position of the static node of more close purpose static node in the geographical position of purpose static node and the highway section, source node place by grid location service GLS;

(2.2) data encapsulation that the first step, source node will send to the purpose static node becomes common IP packet; Second step, whole IP packet is carried out the encapsulation second time, for the second time in the IP packet after the encapsulation, the destination node IP address of header part is the IP address by the static node of more close purpose static node in the highway section, source node place of GLS acquisition, and content part is the geographical position of the destination node after for the second time encapsulation and the whole IP packet in the first step; In the 3rd step, marking this packet is the IP packet; In the 4th step, the geographical position of the destination node after for the second time encapsulation of utilization is selected to carry out the forwarding of IP packet as down hop from the nearest neighbor node of this destination node in the neighbor node tabulation;

When (2.3) being in vehicle node in the highway section and receiving the IP packet, check that at first whether having static node and this static node in the neighbor node tabulation is the destination node of the IP packet that receives, if so, then directly give this static node with the IP data packet delivery; If not having static node or static node in the neighbor node tabulation is not destination node, vehicle node is then utilized the geographical position of destination node, selects to carry out the forwarding of IP packet as down hop from the nearest neighbor node of destination node in the neighbor node tabulation; If vehicle node is at time t _WaitIn still can't find correct down hop, then directly abandon this IP packet;

(2.4) when static node receives the IP packet, at first it is carried out the decapsulation first time, thereby obtain the IP address of real destination node, if the IP address is exactly the IP address of this static node, this static node then directly receives this IP packet; If the IP address is not the IP address of this static node, then this static node at first utilizes macroscopical greedy forwarding algorithm to select the next highway section of transmitting, then whole IP packet is carried out Reseal, in the IP packet behind the Reseal, the destination node IP address of header part is to utilize the selected next IP address of transmitting the static node of the highway section other end of macroscopical greedy forwarding algorithm, and content part is the geographical position of the destination node behind the Reseal and the whole IP packet when carrying out for the first time decapsulation; Utilize at last the geographical position of the destination node behind the Reseal, select to carry out the forwarding of IP packet as down hop from the nearest neighbor node of this destination node in the neighbor node tabulation.

4. a kind of vehicle-mounted network routing protocol that utilizes crossing static node auxiliary data to transmit according to claim 3 is characterized in that the concrete steps of the macroscopical greedy forwarding algorithm in the step (2.4) are:

The highway section connected state t of each list item during (2.4.1) static node is at first tabulated according to adjacent static node _StateCalculate time difference corresponding to each list item; Described time difference is by with connected state t in highway section in the list item _StateAnnular chain meter nearest time of preserving deduct that time farthest obtains; This time difference corresponding when some list items surpasses threshold value T _ThreadThe time, represent that highway section corresponding to this list item is in the state of poor connectivity, then the highway section of correspondence is got rid of outside the range of choice of selecting next forwarding highway section; If the corresponding road section of all list items all is in the state of poor connectivity, then select the highway section that wherein connectedness is the strongest to carry out the forwarding of IP packet as next one forwarding highway section; If not to vehicle node that should the highway section, then select the suboptimum highway section in the neighbor node of the static node tabulation;

(2.4.2) got rid of the highway section of poor connectivity after, static node is at first according to highway section propagation delay time t _DelayCalculate the data transmission distance D of each remaining in the tabulation of neighbours' static node list item _Trans, then select D _TransMinimum corresponding road section is transmitted the highway section as the next one and is carried out the forwarding of IP packet; If not to vehicle node that should the highway section, then select the suboptimum highway section in the neighbor node of the static node tabulation.

5. a kind of vehicular ad hoc network Routing Protocol that utilizes static intersection node auxiliary data to transmit according to claim 4, it is characterized in that in the step (2.4.2) according to highway section propagation delay time t _DelayCalculated data transmission range D _Trans:

If data transmission bauds is v _Trans, with v _TransWith the tabulate highway section propagation delay time t of some list items of adjacent static node _DelayMultiply each other, obtain the time delay distance D of corresponding road section _DelayDescribed time delay distance D _DelayThe expression data are transferred to the required pseudo range of corresponding road section other end static node from this static node, but not real geographic distance; In higher, the connective strong highway section of vehicle closeness, the time delay weak point that the transmission of data is required, time delay distance D _DelayLittle and geographic distance is not necessarily little, on the contrary the vehicle closeness is lower, in the highway section of poor connectivity, the transmission of data required the time prolong time delay distance D _DelayLarge and geographic distance is not necessarily large; Described data transmission bauds v _TransComputing formula as follows:

$v_{\mathrm{trans}}=\frac{R}{t_{\mathrm{trans}}}$

Wherein R represents the average effective communication distance of vehicle node and static node, and t _TransExpression node processing data, transmission data, data one-hop propagation, next-hop node receive the required time of data;

Data are transferred to the time delay distance D of the static node of a highway section other end that is attached thereto from current static node _DelaySelect this highway section as the next one to transmit highway section when carrying out data retransmission, the transmission range D of current static node and purpose static node to the geometric distance L of purpose static node with having consisted of with this highway section other end static node _Trans, specific formula for calculation is as follows:

D _trans=D _delay+L。

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