CN105072027A - Video downloading method in communication between vehicle and road facility - Google Patents

Abstract

The invention discloses a video downloading method in communication between a vehicle and a road facility, used for mainly solving the problems that videos cannot be played and resources are wasted due to incomplete video downloading within a link connection time currently. The video downloading method comprises the following implementation steps that: (1), a node having video requests sends request information to the road facility; (2), the road facility judges whether the video requests can be serviced or not; (3), the road facility sequences serviced requests according to the importance of requested videos; (4), the priority of the requests is calculated based on importance sequencing; (5), resources are distributed to the requests based on the priority sequence; and (6), the road facility downloads the videos to the request node based on a resource distribution result. The video downloading method disclosed by the invention is capable of providing preferential resource downloading for important videos required by a plurality of users; user requirements are satisfied to the most extent; the video playing quality is improved; and thus, the video downloading method can be applicable to communication between the vehicle and the road facility.

Description

The method for downloading video in communication is established on vehicle and road

Technical field:

The invention belongs to communication technical field, relate generally to the method for downloading video in vehicle self-organizing network VANET, can be used for vehicle and road establish between communication.

Background technology:

Vehicle self-organizing network is a kind of service-oriented user oriented self-organizing network, it sets the radio communication namely between V2I to provide many services as user by between vehicle and vehicle and V2V and vehicle and road, and these services will be divided into Security Service and non-safety service.Security Service comprises auxiliary driving and arranges caution system; Non-safety service comprises convenience service and recreational service.In security application, conveniently can understand the detailed circumstance of traffic accident so that the process of follow-up work by the transmission of video and picture; Non-safety application is mainly applied as master with recreational, inherently needs a large amount of Voice & Video transmission to meet the requirement of user.As can be seen here, transmission of video has irreplaceable effect in vehicle self-organizing network.But, vehicle and road establish in communication download required video time, the problem existed is that the video downloaded is imperfect, and main manifestations is when between vehicle and road are established, communication link exists, and complete for the video of request download cannot can not be play and waste bandwidth resources by this vehicle.Video importance is not considered when another problem existed is vehicle foradownloaded video, major embodiment is for working as the same video of multiple vehicle requests, illustrate that this video requirement amount is high, if preferentially meet the download of this video, can be met the demand of several users again by the communication between vehicle and vehicle, this mode to a certain degree can improve user's request simultaneously.In addition, when initiation request established by multiple vehicle simultaneously to road time, road establishes the scheduling problem of the service order to vehicle to be also worthy of consideration.Therefore, a rational vehicle and road establish the video download mechanism in communication to be very important for improving Consumer's Experience.

In existing video download mechanism, great majority consider that the deadline of solicited message and the size of request video calculate a priority, carrys out service requesting node, do not take into account integrity of video and importance problem according to the order of priority.Typical mechanism has vehicle environmental perception descending scheduling mechanism VECADS and vehicle to establish access dispatching mechanism D*S to road.VECADS mechanism is by considering real-time information of vehicles, i.e. position, speed etc., calculates a suitable dispatching sequence, reaches a balance between network throughput and service fairness.This process comprises the tracking of vehicle real time data, the self adaptation of transfer rate, the selection of vehicle and scheduling.Do not consider the deadline of the solicited message of vehicle time this process considers the information of actual vehicle, when the deadline of solicited message arrives time, road is established and will be abandoned this request data package automatically and terminate ongoing transmitting procedure; And this mechanism does not consider video importance problem.D*S mechanism carrys out calculating priority level DS_value by the deadline and data volume size considering solicited message.According to the principle of Priority Service flash request, road establishes first little to priority DS_value request to serve.But in the deadline of solicited message, vehicle may roll the communication zone that road is established away from, now link interruption and cannot communicating.Therefore this mechanism adopts deadline to be irrational when calculating priority level, and video may be caused to download incomplete problem.

Summary of the invention:

The object of the invention is to the deficiency for above-mentioned prior art, propose vehicle and road and establish method for downloading video in communication, to improve mounted mass under video, meet consumers' demand.

Technical scheme of the present invention, comprises the steps: for achieving the above object

(1) node of video requirement is had to send to road to establish solicited message;

(2) road is established and is judged whether video request can be serviced:

2a) when road establish receive solicited message time, record its ID i, calculate the time of staying t of this node in oneself communication range according to the position in its solicited message, speed and acceleration information _i, and record is carried out to this time of staying set up required list;

2b) the deadline d recording this solicited message is established on road _i, in conjunction with time of staying t _icalculate T effective time _i, and be recorded in required list;

2c) the video information feature V of record request is established on road _i, search for and record this video size D _i;

2d) estimate T effective time _iinterior Downloadable video heap(ed) capacity A _i;

2e) by video heap(ed) capacity A _iwith video size D _icontrast: if A _i>=D _i, then this request can be serviced; Otherwise this request can not be serviced, road is established and is abandoned this solicited message and delete its relevant information in required list;

(3) calculating priority level P _i:

Request number of times N 3a) in initialization request table _ibe 1, according to the video information feature V in required list _i, same video information characteristics V will be had _irequest number be added, and by outcome record at corresponding request number of times N _iin;

3b) by the request in required list according to request number of times N _idescending;

3c) for video information feature V _iidentical request, contrast its effective time of T is established on road _i, there is T the longest effective time _irequest ID copy hurdle place, No. ID that records other request of this video, and the relevant information that other request of deleting this video is corresponding;

3d) priority P of asking video in computation requests table is respectively established on road _i;

3e) for having same request times N _irequest, according to priority P _isize, road is established and is carried out descending to request;

(4) Resourse Distribute:

4a) regard the request of j sequence number front in required list as an entirety, j increases by 1, calculates front j the minimum time of staying t asking to establish on road in communication range _j'=min{t ₁, t ₂..., t _jand the minimum deadline d of a front j node _j'=min{d ₁, d ₂..., d _j, then by minimum time of staying t _j' and minimum deadline d _j' calculate the T minimum effective time of front j request _j';

4b) estimate T minimum effective time _j' in can download front j the maximum data capacity A asked _j';

J request video size sum before 4c) calculating j+1 request video size sum D before adopting identical method to calculate _j+1';

4d) to the maximum data capacity A of front j request _j', front j request video size sum D _j' and front j+1 request video size sum D _j+1' contrast: if D _j'≤A _j' < D _j+1', then establish can front j request simultaneously in service request table on road, and ask the bandwidth ratio in downloading process to be set to front j the D asked by front j _jratio; If D _j' < D _j+1'≤A _j', then j is added 1, repeat said process, until find full then D _j'≤A _j' < D _j+1' j value;

(5) video download communication:

5a) according to the resource allocation mechanism of step (4), road is established and is downloaded its video of asking to requesting node, if solicited message ID copy hurdle is empty, then road has been established and downloaded its video of asking, and terminates this request task; If solicited message ID copy hurdle is not empty, then road is established and is added in video packets of data packet header by copy hurdle No. ID, and downloads its video of asking to requesting node;

After 5b) requesting node receives video packets of data, first check video packets of data packet header, check whether it has other requesting node No. ID: if do not had, then node terminates this request task; If had, then the node receiving video packets of data is with oneself for source node, and node for the purpose of other node of No. ID in packet header, adopts the radio communication between node and node to complete this video download request, and terminate this request task.

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

(1) the present invention is owing to utilizing content integrity condition to judge whether video can be serviced, so serviced request video can be downloaded, ensure that the integrality that video is downloaded;

(2) the present invention is owing to have employed resource allocation mechanism, and carrys out auxiliary video download, so can meet consumers' demand by the communication between vehicle and vehicle.

Accompanying drawing explanation

Fig. 1 is the scene graph that the present invention uses;

Fig. 2 is realization flow figure of the present invention.

Embodiment

With reference to Fig. 1, the scene that the present invention uses is the two kinds of vehicles distributed on the length one section of road that is S, wherein No. ID be 1 ~ 13 node be the node having video requirement, residue node is the node not having video requirement, road is set in S/2 position, road is established to enter the Internet and is downloaded the video of node request, and R is range for wireless communication, and R=S/2.

With reference to Fig. 2, detailed implementation step of the present invention is as follows:

Step 1: have the node of video requirement to send to road to establish solicited message.

1a) when road service of establishing be over one ask time, broadcast the idle condition information of oneself;

1b) when there being the node listens of video requirement to this idle condition information, establish transmission request information to road, this solicited message comprise No. ID of requesting node, speed, acceleration, positional information, the information characteristics of request video and the deadline of solicited message.

Step 2: road is established and judged whether video request can be serviced.

2a) when road set receive No. ID solicited message as i time, in solicited message No. ID is recorded and sets up required list;

2b) also Record ID number is calculated in road design is the time of staying t of requesting node in the communication range of oneself of i _i:

$t_i=\frac{\sqrt{v_i-2a_i(L_{b-i}-L_{c-i})}-v_i}{a_i},$

Wherein, a _i, v _iand L _c-ibe respectively the acceleration of the requesting node that No. ID is i, speed and positional information; L _b-ifor the position of communication boundary;

2c) road sets Record ID number as the deadline d of the solicited message of i _i, in conjunction with time of staying t _icalculate T effective time _i, and be recorded in required list, its computing formula is as follows:

$\begin{array}{c}{T}_i=\left\{\begin{array}{cc}{t}_i,& t_i<d_i-t_c\\ d_i-t_c,& t_i\&GreaterEqual;d_i-t_c\end{array}\right.\\ =\min \left\{t_i,d_i-t_c\right\}\end{array}$

Wherein, d _ibe No. ID be solicited message deadline, t _cit is current time;

2d) road sets Record ID number as the solicited message video information feature V of i _i, search for and record this video size D _i;

2e) application No. ID T effective time as the request of i is set on road _i, estimate this request T effective time _ithe interior maximum amount of data A that can transmit _i:

A _i＝T _i×r

Wherein, r is maximum data transfer rate;

2f) road is set No. ID video heap(ed) capacity A as the request of i _ibe the video size D of the request of i with No. ID _icontrast: if A _i>=D _i, then this No. ID is that the request of i can be serviced; Otherwise No. ID is that the request of i can not be serviced, road is set and is deleted its relevant information in required list by abandoning No. ID as the solicited message of i;

After completing this process, the request of recording in required list all can be serviced, as shown in Table 1.

Table one can be serviced node request

Step 3: road establish to can be serviced request according to request video importance sort.

Request number of times N 3a) in initialization request table _ibe 1;

3b) entirety checks video information feature V in required list _i, same video information characteristics V will be had _irequest number be added, and by outcome record at corresponding request number of times N _iin; Can find out from required list table one wherein No. ID be 3,10,8 the identical video V of node request _a, No. ID be 7,5 the identical video V of node request _f, node ID number is the node request same video V of 9,11 _z, therefore No. ID is the request number of times of 3,8,10 correspondences is 3; No. ID is the request number of times of 7,5 correspondences is 2; No. ID is the request number of times of 9,11 correspondences is 2, and other No. ID corresponding request number of times is 1;

3c) road is established and is arranged these 11 requests according to request number of times, as shown in Table 2;

Table two is by the node request of request video importance sequence

3d) for video information feature V in table two _iidentical request, contrast its effective time of T is established on road _i, there is T the longest effective time _irequest ID copy hurdle place, No. ID that records other request of this video, and the relevant information that other request of deleting this video is corresponding;

Describe according to above-mentioned, No. ID 3,8 being recorded to No. ID is in the copy of 10, and No. ID 7 being recorded to No. ID is in the copy of 5, and No. ID 11 being recorded to No. ID is in the copy of 9, and deletes the solicited message that No. ID is 3,8,7,11 correspondences.

Step 4: based on the priority of importance ranking computation requests.

4a) road set calculate respectively now No. ID as 10,5,9,12,2,4,6 the priority P of request _i, its computing formula is as follows:

$P_i=w_1\&times;\left(\frac{T_i}{T_m}\right)+w_2\&times;\left(\frac{D_i}{D_m}\right)$

$\begin{array}{cc}s.t.& T_m=\frac{2R}{v_m}\end{array},$

D _m＝T _m×r

Wherein, T _ithe effective time of the request that No. ID is i, D _ibe No. ID request video size for i, R is maximum communication distance, v _maverage nodal travel speed, T _mthe average time in communication distance is rested on, D for node _mmaximum time of staying T _mthe average data volume can transmitted in time, r is maximum data transfer rate, w ₁and w ₂be the different weight factor of two numerical value and value is 0.4 and 0.6 respectively;

After 4c) having calculated, for having same request times N _irequest, according to priority P _isize, road is established and is carried out descending to request, as shown in Table 3.

Table three is with the node request of priority

Step 5: Resourse Distribute is carried out to request based on priority orders.

5a) after Request Priority calculating has been established on road, according to the order in table three, road is established and is carried out Resourse Distribute to the download of request; First formula t is utilized _j'=min{t ₁, t ₂..., t _jand d _j'=min{d ₁, d ₂..., d _jcalculate the minimum time of staying t of previous request ₁' and the minimum deadline d of previous node ₁';

5b) according to T _j'=min{t _j', d _j'-t _ccalculate the T minimum effective time of previous request ₁'=min{t ₁', d ₁'-t _c;

5c) utilize A _j'=T _j' × r calculates the maximum data capacity A of previous request ₁';

5d) utilize calculate previous request video size sum D ₁' and the first two request video size sum D ₂';

5e) by the maximum data capacity A of previous request ₁', previous request video size sum D ₁' and the first two request video size sum D ₂' this three contrasts: if D ₁' < D ₂'≤A ₁', then 1 is added to j, calculate the first two maximum data capacity A successively ₂', the first two request video size sum D ₂' and first three request video size sum D ₃';

5f) by the maximum data capacity A of the first two request ₂', the first two request video size sum D ₂' and first three request video size sum D ₃' this three contrasts: if D ₂'≤A ₂' < D ₃', then road set can simultaneously to No. ID as 10 and 5 these two requests are served, and in downloading process these two request bandwidth ratios be D ₁₀: D ₅.

Step 6: establish foradownloaded video to requesting node based on resource allocation result road.

6a) draw by step 5, road set simultaneously service ID number as 10 and 5 request, first No. ID, inspection is the copy hurdle of 10 and 5, if find, No. ID is there are No. ID 3 and 8 in the copy of 10, and No. ID is 5 the intermediate hurdles of request copy exist No. ID 7, then by No. ID 3 and 8, added to the video packets of data packet header that No. ID is the request of 10, and No. ID 7 is added to the video packets of data packet header that No. ID is the request of 5;

6b) road set to download respectively from internet and transmit corresponding request video to No. ID as 10 and 5 node;

6c) No. ID be 10 and 5 requesting node receive request video packets of data, check video packets of data header packet information respectively, No. ID be 10 node find that there are No. ID 3 and 8 in the video packets of data packet header received, then No. ID be 10 node with oneself for source node, successively using No. ID be the node of 3 and 8 as destination node, adopt greedy edge stateless route GPSR agreement or other agreements being adapted to communicate between vehicle with vehicle; If No. ID is 5, node finds that the video packets of data packet header received has No. ID 7, then No. ID be 5 node with oneself for source node, using No. ID be the node of 7 as destination node, adopt greedy edge stateless route GPSR agreement or other agreements being adapted to communicate between vehicle with vehicle.

Claims (5)

1. the method for downloading video in communication is established on vehicle and road, comprises the steps:

(1) node of video requirement is had to send to road to establish solicited message;

(2) road is established and is judged whether video request can be serviced:

2a) when road establish receive solicited message time, record its ID i, calculate the time of staying t of this node in oneself communication range according to the position in its solicited message, speed and acceleration information _i, and record is carried out to this time of staying set up required list;

2b) the deadline d recording this solicited message is established on road _i, in conjunction with time of staying t _icalculate T effective time _i, and be recorded in required list;

2c) the video information feature V of record request is established on road _i, search for and record this video size D _i;

2d) estimate T effective time _iinterior Downloadable video heap(ed) capacity A _i;

2e) by video heap(ed) capacity A _iwith video size D _icontrast: if A _i>=D _i, then this request can be serviced; Otherwise this request can not be serviced, road is established and is abandoned this solicited message and delete its relevant information in required list;

(3) calculating priority level P _i:

Request number of times N 3a) in initialization request table _ibe 1, according to the video information feature V in required list _i, same video information characteristics V will be had _irequest number be added, and by outcome record at corresponding request number of times N _iin;

3b) by the request in required list according to request number of times N _idescending;

3c) for video information feature V _iidentical request, contrast its effective time of T is established on road _i, there is T the longest effective time _irequest ID copy hurdle place, No. ID that records other request of this video, and the relevant information that other request of deleting this video is corresponding;

3d) priority P of asking video in computation requests table is respectively established on road _i;

3e) for having same request times N _irequest, according to priority P _isize, road is established and is carried out descending to request;

(4) Resourse Distribute:

4a) regard the request of j sequence number front in required list as an entirety, j increases by 1, calculates front j the minimum time of staying t asking to establish on road in communication range _j'=min{t ₁, t ₂..., t _jand the minimum deadline d of a front j node _j'=min{d ₁, d ₂..., d _j, then by minimum time of staying t _j' and minimum deadline d _j' calculate the T minimum effective time of front j request _j';

4b) estimate T minimum effective time _j' in can download front j the maximum data capacity A asked _j';

J request video size sum before 4c) calculating j+1 request video size sum D before adopting identical method to calculate _j+1';

4d) to the maximum data capacity A of front j request _j', front j request video size sum D _j' and front j+1 request video size sum D _j+1' contrast: if D _j'≤A _j' < D _j+1', then establish can front j request simultaneously in service request table on road, and ask the bandwidth ratio in downloading process to be set to front j the D asked by front j _jratio; If D _j' < D _j+1'≤A _j', then j is added 1, repeat said process, until find full then D _j'≤A _j' < D _j+1' j value;

(5) video download communication:

5a) according to the resource allocation mechanism of step (4), road is established and is downloaded its video of asking to requesting node, if solicited message ID copy hurdle is empty, then road has been established and downloaded its video of asking, and terminates this request task; If solicited message ID copy hurdle is not empty, then road is established and is added in video packets of data packet header by copy hurdle No. ID, and downloads its video of asking to requesting node;

After 5b) requesting node receives video packets of data, first check video packets of data packet header, check whether it has other requesting node No. ID: if do not had, then node terminates this request task; If had, then the node receiving video packets of data is with oneself for source node, and node for the purpose of other node of No. ID in packet header, adopts the radio communication between node and node to complete this video download request, and terminate this request task.

2. method according to claim 1, wherein said step 2d) middle estimation T effective time _iinterior Downloadable video heap(ed) capacity A _i, carry out as follows:

2d1) time of staying t that No. ID is the requesting node of i is calculated in road design _i:

$t_i=\frac{\sqrt{v_i-2a_i(L_{b-i}-L_{c-i})}-v_i}{a_i},$

Wherein a _i, v _iand L _c-ibe respectively the acceleration of the requesting node that No. ID is i, speed and positional information, L _b-ifor communication boundary position;

2d2) use time of staying t _icalculate T effective time of the request that No. ID is i _i:

$\begin{array}{c}{T}_i=\left\{\begin{array}{cc}{t}_i,& t_i<d_i-t_c\\ d_i-t_c,& t_i\&GreaterEqual;d_i-t_c\end{array}\right.\\ =\min \left\{t_i,d_i-t_c\right\}\end{array},$

Wherein, d _ibe No. ID be solicited message deadline, t _cit is current time;

2d3) use T effective time _iestimate No. ID request largest data transfer amount A being i _i:

A _i＝T _i×r，

Wherein, r is maximum data transfer rate, T _ifor effective time.

3. according to the method described in claim 1, wherein said step 3c) in calculate the priority P that No. ID is the requesting node of i _i, its computing formula is as follows:

$P_i=w_1\&times;\left(\frac{T_i}{T_m}\right)+w_2\&times;\left(\frac{D_i}{D_m}\right)$

$\begin{array}{cc}s.t.& T_m=\frac{2R}{v_m}\end{array},$

D _m＝T _m×r

Wherein, T _ithe effective time of the request that No. ID is i, D _ibe No. ID request video size for i, R is maximum communication distance, v _maverage nodal travel speed, T _mthe average time in communication distance is rested on, D for node _mmaximum time of staying T _mthe average data volume can transmitted in time, w ₁and w ₂be the different weight factor of two numerical value and w ₁+ w ₂=1.

4. according to the method described in claim 1, wherein said step 4b) in the T minimum effective time of j node before estimation _j' the interior maximum data capacity A that can download _j', carry out as follows:

The T minimum effective time of j node before 4b1) calculating _j':

$\begin{array}{c}{T_j}^{\&prime;}=\left\{\begin{array}{cc}{t_j}^{\&prime;},& {t_j}^{\&prime;}<{d_j}^{\&prime;}-t_c\\ {d_j}^{\&prime;}-t_c,& {t_j}^{\&prime;}\&GreaterEqual;{d_j}^{\&prime;}-t_c\end{array}\right.\\ =\min \left\{{t_j}^{\&prime;},{d_j}^{\&prime;}-t_c\right\}\end{array}$

Wherein, t _j' be front j request to establish on road minimum time of staying in communication range and, d _j' be the minimum deadline of a front j node, t _cit is current time;

4b2) with T minimum effective time _j' calculate the T minimum effective time of a front j node _j' in the most A of the maximum data capacity of the first two request that can download _j':

A _j'＝T _j'×r

Wherein, r is maximum data transfer rate.

5. method according to claim 1, wherein said step 5b) in communication protocol between vehicle with vehicle V2V adopts the greedy edge stateless route GPSR of classics or other agreements being adapted to communicate between vehicle with vehicle.