CN109615857B - Deployment and scheduling method and device for roadside units in urban vehicle-mounted network - Google Patents

Deployment and scheduling method and device for roadside units in urban vehicle-mounted network Download PDF

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CN109615857B
CN109615857B CN201811567375.0A CN201811567375A CN109615857B CN 109615857 B CN109615857 B CN 109615857B CN 201811567375 A CN201811567375 A CN 201811567375A CN 109615857 B CN109615857 B CN 109615857B
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唐晓岚
陈潇然
陈文龙
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China Southern Power Grid Internet Service Co ltd
Dongguan Pengbo Information Technology Co ltd
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Abstract

The invention discloses a method and a device for deploying and scheduling roadside units in an urban vehicle-mounted network, wherein the method comprises the following steps: step S1, selecting a plurality of target intersections within the target area range according to the preset priority of each intersection, and deploying a plurality of roadside units according to the plurality of target intersections; step S2, identifying and obtaining a plurality of hot spot areas in each preset time period in the target area range according to a density-based clustering algorithm; and step S3, scheduling roadside units within the hot spot area range to work according to the plurality of hot spot areas within each preset time period. The method can regulate and control the working state and the dormant state of the roadside unit within a specified time period on the premise of not influencing connection and service quality, and improves the utilization rate of energy resources of a vehicle-mounted network.

Description

Deployment and scheduling method and device for roadside units in urban vehicle-mounted network
Technical Field
The invention relates to the technical field of roadside unit deployment, in particular to a method and a device for deploying and scheduling roadside units in an urban vehicle-mounted network.
Background
At present, most applications of urban vehicle-mounted networks require continuity of vehicle communication connection, and the communication range of a roadside unit is usually larger than that of a vehicle-mounted node, so that the vehicles can be helped to realize end-to-end connection. However, in order to achieve communication coverage of the roadside units to the whole area, a large number of roadside units need to be deployed along the road, and from the perspective of energy, the deployment of a large number of roadside units and the requirement of the roadside units to maintain the continuity of communication connection consume excessive energy.
In the related art, most researches on deployment and scheduling of urban vehicle-mounted network side units focus on the deployment cost of the side units and the service quality of vehicle data requests, however, due to the difference of urban traffic hot spot areas in different time periods, the side units are still in a working state under the condition of not participating in communication connection, so that the waste of resources is caused, and therefore, on the premise of not influencing the service quality of the vehicle data requests, the working state and the dormant state of the side units are regulated and controlled, so that the energy consumption is reduced, and the method is still a challenging problem.
Disclosure of Invention
The technical problem solved by the invention is that a large number of roadside units in a vehicle-mounted self-organizing network are deployed and are required to maintain communication connection, so that the problem of excessive energy consumption is solved. In an urban vehicle-mounted network, traffic flow distribution in different areas is uneven, and how to select the deployment position of a roadside unit influences the service performance of the vehicle-mounted network; meanwhile, traffic flow is not uniformly distributed in different time periods, and how to effectively schedule the roadside units (i.e., regulate and control the working time and the sleep time of the roadside units) also affects the energy resource utilization rate of the vehicle-mounted network. The scheme of the invention seeks a mode, and regulates and controls the working state and the dormant state of the roadside unit within a specified time period on the premise of not influencing connection and service quality so as to ensure that the total energy consumed by the whole roadside unit system is as small as possible.
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, one objective of the present invention is to provide a method for deploying and scheduling roadside units in an urban vehicle-mounted network, which can regulate and control the working state and the dormant state of the roadside units within a specified time period without affecting connection and service quality, thereby improving the energy resource utilization rate of the vehicle-mounted network.
The invention also aims to provide a deployment and scheduling device of roadside units in the urban vehicle-mounted network.
In order to achieve the above object, an embodiment of an aspect of the present invention provides a method, including the following steps: step S1, selecting a plurality of target intersections in the target area range according to the preset priority of each intersection, and deploying a plurality of roadside units according to the target intersections; step S2, identifying and obtaining a plurality of hot spot areas in each preset time period in the target area range according to a density-based clustering algorithm; step S3, scheduling the roadside units in the hot spot area range to work according to the plurality of hot spot areas in each preset time period.
The method for deploying and scheduling the roadside units in the urban vehicle-mounted network ensures that the total energy consumed by the whole roadside unit system is as small as possible through the deployment and scheduling of the roadside units, ensures the service performance of the vehicle-mounted network by considering the priority and the uniformity through the deployment of the roadside units, and effectively schedules the roadside units by identifying hot spot areas aiming at the problem of uneven distribution of traffic flow in different areas in different time periods, so that the working state and the dormant state of the roadside units are regulated and controlled in a specified time period on the premise of not influencing the connection and the service quality, and the energy resource utilization rate of the vehicle-mounted network is improved.
In addition, the method for deploying and scheduling roadside units in the urban vehicle-mounted network according to the above embodiment of the present invention may further have the following additional technical features:
further, in an embodiment of the present invention, the step S1 further includes:
step S11, set the target crossroad VRIntersection set C covered by roadside unitsRAre all initialized to null;
step S12, arranging each intersection in descending order according to the preset priority of each intersection;
step S13, judging the CRWhether each intersection is covered, if not, executing the steps S14 to S17 in a loop;
step S14, converting the VRIs given to a preset target intersection set TVRAnd mixing said CRIs assigned to the intersection set TC covered by the preset roadside unitR；
Step S15, selecting the intersection v with the highest preset priorityiWherein v isi∈V-VRAnd V is the set of all crossroads, and the crossroad V is judgediWhether a preset condition is met, if so, VRTo which said v is addediSaid C isRAdding set CR(vi)，CR(vi) Roadside unit deployed for ith intersectionAnd performing step S16, if not, sequentially finding intersections meeting preset conditions according to the descending order of preset priority of each intersection, and performing step S15, wherein the preset conditions are intersections viIs out of CRWithin the range;
step S16, for intersection vlWherein v isl∈CR(vi)-TCRIf p isi-plWithin the range of the preset threshold value, reserving the intersection vlAnd proceeds to step S17, otherwise the intersection v is discardedlContinuing to step S16 if TCR∪CR(vl) The number of elements in the set is more than CRThe number of elements in the set is reserved for the intersection vlAnd proceeds to step S17, otherwise, proceeds to step S16, where the intersection viIs recorded as piSaid intersection vlIs recorded as pl；
Step S17, at all vl∈CR(vi)-TCRAfter all the determinations are finished, the step S16 is ended, and TC is selectedR∪CR(vl) Set corresponding maximum crossroad vl，
Step S18, set VRReplacement as TVR∪vlSet C ofRReplacement by TCR∪CR(vl) End step S14 to finish VRThe roadside unit corresponding to each target intersection included in (1).
Further, in an embodiment of the present invention, the calculation formula of the preset priority is:
Figure GDA0002741991270000031
wherein the content of the first and second substances,
Figure GDA0002741991270000032
min(Xveh) A set of representations XvehMinimum value of middle element, max (X)veh) A set of representations XvehMaximum value of middle element, min (X)con) A set of representations XconMinimum value of middle element, max (X)con) A set of representations XconThe maximum value of the medium element.
Further, in one embodiment of the present invention, two influencing factors
Figure GDA0002741991270000033
And
Figure GDA0002741991270000034
the occupied weights are respectively marked as wvehAnd wconWherein w isveh+wcon＝1。
Further, in an embodiment of the present invention, the step S2 further includes:
step S21, dividing the longitude span and the latitude span of the target area into a span segments, each having a span of b, to divide the target area into a grid units u (k) with a size of b × b, wherein a, b and k are positive integers;
step S22, obtaining grid density of each grid unit U (k) according to the GPS data points mapped to each grid unit U (k) in each preset time period
Figure GDA0002741991270000035
Step S23, finding out the grid density in each preset time period
Figure GDA0002741991270000036
All grid cell sets Q oftAnd identifying and obtaining a plurality of hot spot areas in each preset time period according to the density-based clustering algorithm.
Further, in an embodiment of the present invention, the step S23 further includes: if the grid cell does not satisfy the grid density
Figure GDA0002741991270000037
The grid cell is marked as a noise point.
Further, in an embodiment of the present invention, the step S3 further includes:
step S31, setting the search radius of the density-based clustering algorithm as epsilon and the neighborhood density threshold as MinPts, and initializing the hot spot region set S in each preset time periodtIf the time is empty, the following steps are executed in each preset time period;
step S32, marking the set QtAll grid cells in the grid are unsearched grid cells;
step S33, from the set QtArbitrarily select one unsearched grid cell u (k), and perform steps S34 to S37;
step S34, marking the un-searched grid unit U (k) as the searched grid unit, if there are at least MinPts sets Q in the search radius range of the searched grid unit U (k)tThen a hot spot area is created
Figure GDA0002741991270000041
And adding the searched grid cell U (k) to
Figure GDA0002741991270000042
Performing the following steps; otherwise, marking the noise points as noise points;
step S35, search the radius range of the grid unit U (k) in the set QtAdding other grid cells in the set N, and executing the step S36 on each unsearched grid cell U (k') ∈ N in the set N;
said step S36, marking said unsearched grid unit U (k ') as a searched grid unit, if there are at least MinPts sets Q in the search radius of said U (k')/rangetThen these elements are added to the set N; if said U (k') does not belong to StIn any hot spot area, add U (k') to
Figure GDA0002741991270000043
Performing the following steps; otherwise, marking the noise points as noise points;
said step S37, until set QtAll grid cells in the set are searched, and the set of hot spot areas in the preset time period is St；
Step S38, initializing all deployed roadside units to be in a dormant state, and collecting hot spot areas StEach hot spot region of
Figure GDA0002741991270000044
If deployed roadside unit vR_iIn the hot spot region
Figure GDA0002741991270000045
And if the roadside unit is within the range, setting the roadside unit to be in a working state.
In order to achieve the above object, an embodiment of another aspect of the present invention provides a device for deploying and scheduling roadside units in an urban vehicle-mounted network, including: the deployment module is used for selecting a plurality of target intersections within the range of a target area according to the preset priority of each intersection and deploying a plurality of roadside units according to the target intersections; the identification module is used for identifying and obtaining a plurality of hot spot areas in each preset time period in the target area range according to a density-based clustering algorithm; and the scheduling module is used for scheduling the roadside units within the hot spot area range to work according to the plurality of hot spot areas within each preset time period.
The deployment and scheduling device for the roadside units in the urban vehicle-mounted network ensures that the total energy consumed by the whole roadside unit system is as small as possible through the deployment and scheduling of the roadside units, ensures the service performance of the vehicle-mounted network by considering the priority and the uniformity through the deployment of the roadside units, and effectively schedules the roadside units by identifying hot spot areas aiming at the problem of uneven distribution of traffic flow in different areas in different time periods, so that the working state and the dormant state of the roadside units are regulated and controlled in a specified time period on the premise of not influencing the connection and the service quality, and the energy resource utilization rate of the vehicle-mounted network is improved.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a flow chart of a method for deploying and scheduling roadside units in a vehicular ad hoc network in a city according to an embodiment of the present invention;
FIG. 2 is a flow chart of a method for deploying and scheduling roadside units in a vehicular ad hoc network in a city according to an embodiment of the present invention;
FIG. 3 is a flow diagram of deploying a roadside unit according to one embodiment of the present invention;
FIG. 4 is a flow chart of identifying hot spot areas and scheduling wayside units according to one embodiment of the present invention;
fig. 5 is a schematic structural diagram of a deployment and scheduling apparatus for roadside units in a city vehicle-mounted network according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The following describes a method and a device for deploying and scheduling roadside units in an urban vehicle-mounted network according to an embodiment of the present invention with reference to the accompanying drawings, and first, a method for deploying and scheduling roadside units in an urban vehicle-mounted network according to an embodiment of the present invention will be described with reference to the accompanying drawings.
Fig. 1 is a flowchart of a method for deploying and scheduling roadside units in a city vehicle-mounted network according to an embodiment of the present invention.
As shown in fig. 1, the method for deploying and scheduling roadside units in a city vehicle-mounted network includes the following steps:
and step S1, selecting a plurality of target intersections within the target area range according to the preset priority of each intersection, and deploying a plurality of roadside units according to the plurality of target intersections.
It will be appreciated that, as shown in fig. 2, the roadside units are first deployed by selecting appropriate intersections throughout the city based on priority, so that there are as few roadside units as possible and the communication range covers all intersections.
The preset priority is the priority of the intersection, and is determined by the density of the traffic flow passing through the intersection and the connectivity of the intersection and other intersections, wherein the connectivity of the intersection is determined by the number of direct paths between the intersection and other intersections. The influence factor value of the intersection priority should be a normalized value of the original value, and the value range thereof is controlled between 0 and 1.
It should be noted that the target intersection is an intersection where roadside units are deployed, and in the embodiment of the present invention, the intersection where the roadside units are deployed is set as VRDeployment at the ith intersection is denoted as vR_iAnd is and
Figure GDA00027419912700000610
marking the set of intersections covered by the deployed roadside units as CRAnd the intersection coverage set of the roadside units deployed at the ith intersection is marked as CR(vi). The set of temporarily deployed roadside unit intersections is recorded as TVRAnd the intersection set covered by the temporary deployment roadside unit is marked as TCR。
Further, in an embodiment of the present invention, the calculation formula of the preset priority is:
Figure GDA0002741991270000061
wherein the content of the first and second substances,
Figure GDA0002741991270000062
min(Xveh) A set of representations XvehMinimum value of middle element, max (X)veh) A set of representations XvehMaximum value of middle element, min (X)con) A set of representations XconMinimum value of middle element, max (X)con) A set of representations XconThe maximum value of the medium element.
In one embodiment of the invention, two influencing factors
Figure GDA0002741991270000063
And
Figure GDA0002741991270000064
the occupied weights are respectively marked as wvehAnd wconWherein w isveh+wcon＝1。
In the embodiment of the present invention, all intersections are used as candidate deployment positions of roadside units, and the position set of intersections is denoted as V ═ V1,v2…vi…, and any intersection node is marked as viWherein i is 1,2,3 … n. Let the priority set of intersections be P ═ P1,p2,…pi… } where v is the intersectioniIs denoted as piRecording the influence factor of the traffic density influencing the priority of the intersection as fvehCross road viThe influence factor of the traffic density is recorded as
Figure GDA0002741991270000065
The intersection connectivity influence factor affecting the intersection priority is recorded as fconCross road viThe intersection connectivity influence factor is recorded as
Figure GDA0002741991270000066
Is the original value of the influence factor of the traffic density of the ith intersection, namely the intersection viThe value of the flow rate of the vehicle,
Figure GDA0002741991270000067
is the original value of the connectivity influence factor of the ith intersection, namely the intersection viA crossing quantity value connected with the road; xvehIs the set of the original values of the influence factors of the density of the traffic flow at all intersections, XconIs the set of the original values of all intersection connectivity influence factors; two influence factors
Figure GDA0002741991270000068
And
Figure GDA0002741991270000069
the occupied weights are respectively marked as wveh、wconAnd w isveh+wcon＝1。
Further, in an embodiment of the present invention, the step S1 further includes:
step S11, set the target crossroad VRIntersection set C covered by roadside unitsRAre all initialized to null;
step S12, arranging each intersection in descending order according to the preset priority of each intersection;
step S13, judge CRWhether each intersection is covered, if not, executing the steps S14 to S17 in a loop;
step S14, mixing VRIs given to a preset target intersection set TVRAnd C isRIs assigned to the intersection set TC covered by the preset roadside unitR；
Step S15, selecting the intersection v with the highest preset priorityiWherein v isi∈V-VRV is the set of all crossroads, and the crossroad V is judgediWhether a preset condition is met, if so, VRAdding vi，CRAdding set CR(vi)，CR(vi) And (4) covering the intersection set of the roadside units deployed for the ith intersection, executing the step S16, and if the intersection set does not meet the preset conditions, sequentially finding the intersections meeting the preset conditions according to the descending order of the preset priority of each intersection untilAnd executing step S15, wherein the preset condition is the intersection viIs out of CRWithin the range;
step S16, for intersection vlWherein v isl∈CR(vi)-TCRIf p isi-plWithin the range of the preset threshold value, the crossroad v is reservedlAnd proceeds to step S17, otherwise abandon the intersection vlContinuing to step S16 if TCR∪CR(vl) The number of elements in the set is more than CRThe number of elements in the set is reserved for the intersection vlAnd proceeds to step S17, otherwise, proceeds to step S16, where the intersection viIs recorded as piCross road vlIs recorded as pl；
Step S17, at all vl∈CR(vi)-TCRAfter all the determinations are finished, the step S16 is ended, and TC is selectedR∪CR(vl) Set corresponding maximum crossroad vl；
Step S18, set VRReplacement as TVR∪vlSet C ofRReplacement by TCR∪CR(vl) End step S14 to finish VRThe roadside unit corresponding to each target intersection included in (1).
Specifically, as shown in fig. 3, the method specifically includes:
step 1.1: p is a radical ofiAnd (4) calculating. Crossroad viThe calculation formula of the priority is
Figure GDA0002741991270000071
Wherein
Figure GDA0002741991270000072
Here min (X)veh) A set of representations XvehMinimum value of middle element, max (X)veh) A set of representations XvehMaximum value of medium element; min (X)con) A set of representations XconMinimum value of middle element, max (X)con) A set of representations XconThe maximum value of the medium element.
Step 1.2: initialization VRAnd CRTo make it empty.
Step 1.3: according to piAll the intersections V are arranged in descending order.
Step 1.4: and when the communication range of the deployed roadside unit set does not cover all the intersection sets, circularly executing the subsequent steps.
Step 1.5: will VRIs assigned to TVR，CRTo TCR。
Step 1.6: selection of piHighest value intersection viWherein v isi∈V-VRThe following judgment is made.
Step 1.7: if the intersection viIs out of CRIn the range of VRAdding v to the seti，CRAdding set C to the setR(vi) (ii) a Otherwise, not deploying, finding piThe next highest value continues to determine the condition until it is satisfied.
Step 1.8: for each vl∈CR(vi)-TCRThe following operations are performed cyclically.
Step 1.9: if pi-plWithin a certain threshold value range, the intersection v is reservedlEntering the next step; otherwise, discarding and returning to the previous step.
Step 1.10: if TCR∪CR(vl) The number of elements in the set is more than CRThe number of elements in the set is reserved for the intersection vlEntering the next step; otherwise, discarding and returning to the step 1.8.
Step 1.11: up to all vl∈CR(vi)-TCRAfter all judgment is finished, ending the cycle of the step 1.8; selecting the maximum TCR∪CR(vl) Set corresponding intersections vl。
Step 1.12: will be set VRReplacement as TVR∪vlSet C ofRReplacement by TCR∪CR(vl)。
Step 1.13: end the loop of step 1.4 at VRThe roadside units are deployed at respective intersections contained in (1).
And step S2, identifying and obtaining a plurality of hot spot areas in each preset time period in the target area range according to a density-based clustering algorithm.
It can be understood that, as shown in fig. 2, the embodiment of the present invention finds hot spot areas at different times according to the DBSCAN algorithm. Wherein, for any grid cell, if the grid density is larger than the prescribed threshold, the grid cell is a hot grid cell. According to the clustering algorithm, a unit group formed by a plurality of adjacent heat grid units is a hot spot area, and the shape of the hot spot area is not fixed. In addition, a preset time period may be set by a person skilled in the art according to actual situations, and the embodiment of the present invention is described by dividing 24 hours a day into 12 time periods every two hours, which are denoted as time periods t, where t is 1,2 … 12, as an example.
Specifically, the problem of finding the hot spot area is converted into: the DBSCAN algorithm is a density-based clustering algorithm, which contains two parameters: epsilon (search radius), MinPts (neighborhood density threshold), the algorithm finds out all the neighbor points within epsilon from any core point as the cluster members, and when the number of the neighbor nodes reaches the minimum requirement MinPts, a cluster is formed. The embodiment of the invention finds out the hot spot area set of each time slot by utilizing the DBSCAN algorithm, wherein the grid unit with the grid unit density larger than alpha corresponds to the core point in the DBSCAN algorithm, and from any grid unit meeting the condition, all the neighbor grid units which are within epsilon of the distance between the grid units and also meet the condition are found out as the cluster members of the grid units, and when the number of the neighbor grid units reaches the minimum requirement MinPts, a cluster is formed. This cluster is one of the hot spot regions found by the embodiments of the present invention.
Further, in an embodiment of the present invention, the step S2 further includes:
step S21, dividing the longitude span and the latitude span of the target area into a span segments, each having a span of b, to divide the target area into a grid units u (k) with a size of b × b, wherein a, b and k are positive integers;
step S22, obtaining grid density of each grid unit U (k) according to the GPS data points mapped to each grid unit U (k) in each preset time period
Figure GDA0002741991270000091
Step S23, finding out the grid density in each preset time period
Figure GDA0002741991270000092
All grid cell sets Q oftAnd identifying and obtaining a plurality of hot spot areas in each preset time period according to a density-based clustering algorithm.
Step S23 further includes: if the grid cell does not satisfy the grid density
Figure GDA0002741991270000093
The grid cell is marked as a noise point.
It should be noted that, in the embodiment of the present invention, the entire urban scene is equally divided into a grid units with a size of b × b, where any grid unit is denoted as u (k). For any grid cell, the total number of GPS data points mapped onto U (k) is referred to as the grid density dU(k)And the density of any grid cell at any time interval is recorded as
Figure GDA0002741991270000094
And all will be
Figure GDA0002741991270000095
Is the grid density d of the set of grid cells of arbitrary time period tU(k)The set of grid cells being equal to or more than alpha is marked as Qt. The hot spot areas of any time period t are collected as
Figure GDA0002741991270000096
Wherein
Figure GDA0002741991270000097
Is the g-th hot spot region of the time period t.
And step S3, scheduling roadside units within the hot spot area range to work according to the plurality of hot spot areas within each preset time period.
It can be understood that the working state and the dormant state of the roadside units in the hot spot area are regulated and controlled within a specified time period so as to ensure that the total energy consumed by all the roadside units is as small as possible, and meanwhile, the network connectivity and the service quality of the urban vehicle-mounted network system are maintained.
It should be noted that (1) the service quality requested by the system composed of all roadside units in any time period to the vehicle is measured by the ratio of the number of vehicles covered by the roadside units in the working state in the current time period (i.e., the number of vehicles in the communication range of these roadside units) to the number of vehicles in operation in the current time period.
(2) The roadside unit can be in a working state or a dormant state according to the network service requirement. In a high-density vehicle environment, communication between vehicles is frequent, and most roadside units need to enter a working state; on the contrary, in a low-density environment, the roadside unit can enter a dormant state without participating in communication connection on the premise of not affecting communication performance, so that energy consumption is reduced.
(3) The roadside unit is in a dormant state and consumes no energy when the state is changed.
(4) The 24 hours a day are averagely divided into 12 time periods, each two hours is a time period, and the scheduling scheme of the roadside unit in each time period is unchanged, namely the roadside unit is in a working or dormant state.
(5) Recording the roadside unit set in the working state at any time period t as Xt。
Further, in an embodiment of the present invention, the step S3 further includes:
step S31, setting the search radius of the density-based clustering algorithm as epsilon and the neighborhood density threshold as MinPts, and initializing the hot spot region set S in each preset time periodtThe number of the air bags is empty,executing the following steps in each preset time period;
step S32, label set QtAll grid cells in the grid are unsearched grid cells;
step S33, from the set QtArbitrarily select one unsearched grid cell u (k), and perform steps S34 to S37;
step S34, marking the un-searched grid unit U (k) as the searched grid unit, if there are at least MinPts sets Q in the search radius range of the searched grid unit U (k)tThen a hot spot area is created
Figure GDA0002741991270000101
And adding the searched grid cells U (k) to
Figure GDA0002741991270000102
Performing the following steps; otherwise, marking the noise points as noise points;
step S35, search the radius range of the grid unit U (k) in the set QtAdding other grid cells in the set N, and executing the step S36 on each unsearched grid cell U (k') ∈ N in the set N;
step S36, marking the un-searched grid unit U (k ') as the searched grid unit, if there are at least MinPts sets Q in the search radius range of U (k')tThe elements in (b), then these elements are added to the set N; if U (k') does not belong to StIn any hot spot area, add U (k') to
Figure GDA0002741991270000103
Performing the following steps; otherwise, marking the noise points as noise points;
step S37, until Q is collectedtAll grid cells in the set are searched, and the set of hot spot areas in the preset time period is St；
Step S38, initializing all the deployed roadside units to be in a dormant state, and collecting the hot spot areas StEach hot spot region of
Figure GDA0002741991270000111
If deployed roadside unit vR_iIn the hot spot region
Figure GDA0002741991270000112
And if the roadside unit is within the range, setting the roadside unit to be in a working state.
Specifically, with reference to step S2 and step S3, as shown in fig. 4, the identifying of the hot spot area and the scheduling of the roadside unit specifically include:
step 2.1: and (5) grid division. Dividing longitude and latitude coordinates into small sections with the size of b according to the latitude and longitude coordinate range of the target area, and then dividing the whole area into a small area units with the size of b multiplied by b, wherein the k small area unit is called a grid unit U (k).
Step 2.2: mapping taxi GPS track data into grid units, and calculating the grid density of each grid unit U (k) in each time period t
Figure GDA0002741991270000113
Step 2.3: at each time period t, the grid density is found
Figure GDA0002741991270000114
All grid cell sets Q oftAnd corresponding to the core point object set in the clustering algorithm, and taking the core point object set as one of the inputs of the next step, wherein other grid units which do not meet the conditions are marked as noise points.
Step 2.4: setting a search radius epsilon and a neighborhood density threshold MinPts in a clustering algorithm, and initializing a hot spot region set S of each time periodtIs empty. All the following operations are cyclically performed for each time period t, divided by time period.
Step 2.5: set of labels QtAll grid cells in the list are not searched (UNSEARCH).
Step 2.6: from the set QtRandomly selects a trellis unit u (k) of UNSEARCH, and performs step 2.7 to step 2.12.
Step 2.7: mark this u (k) as SEARCHED (SEARCHED).
Step 2.8: if there are at least MinPts sets Q within the search radius of U (k)tThen a new hot spot area is created
Figure GDA0002741991270000115
And adding U (k) to
Figure GDA0002741991270000116
Performing the following steps; otherwise it is marked as a noise point.
Step 2.9: searching the set Q within the radius of U (k)tThe other grid cells in (b) are added to a new set N.
Step 2.10: for each un-searched U (k'). epsilon.N, step 2.11 is performed.
Step 2.11: marking U (k ') as SEARCHED (SEARCHED), if there are at least MinPts sets Q in the search radius of U (k')/stThe elements in (1), which are added to the set N; if U (k') does not belong to StIn any hot spot area, add U (k') to
Figure GDA0002741991270000123
Performing the following steps; otherwise it is marked as a noise point.
Step 2.12: up to set QtAll grid cells in the set S are searchedtI.e. the hot spot area is assembled during the time period t.
Step 2.13: all deployed roadside units are initialized to a dormant state. Set of hot spot regions StEach hot spot region of
Figure GDA0002741991270000121
The following judgment is made.
Step 2.14: if deployed roadside unit vR_iIn the hot spot region
Figure GDA0002741991270000122
Within the range, the roadside unit is set to an operating state.
According to the method for deploying and scheduling the roadside units in the urban vehicle-mounted network, the total energy consumed by the whole roadside unit system is ensured to be as small as possible through the deployment and scheduling of the roadside units, the service performance of the vehicle-mounted network is ensured through the deployment of the roadside units and the consideration of priority and uniformity, the roadside units are effectively scheduled aiming at the problem of uneven distribution of traffic flow in different areas in different time periods through the identification of hot spot areas, and therefore the working state and the dormant state of the roadside units are regulated and controlled in a specified time period on the premise of not influencing connection and service quality, and the energy resource utilization rate of the vehicle-mounted network is improved.
Next, a deployment and scheduling apparatus of roadside units in an urban vehicle-mounted network according to an embodiment of the present invention will be described with reference to the accompanying drawings.
Fig. 5 is a schematic structural diagram of a deployment and scheduling apparatus for roadside units in a city vehicle-mounted network according to an embodiment of the present invention.
As shown in fig. 5, the apparatus 100 for deploying and scheduling roadside units in a city vehicle-mounted network includes: a deployment module 110, an identification module 120, and a scheduling module 130.
The deployment module 110 is configured to select a plurality of target intersections within a target area range according to a preset priority of each intersection, so as to deploy a plurality of roadside units according to the plurality of target intersections. The identification module 120 is configured to identify a plurality of hot spot regions within each preset time period in the target region range according to a density-based clustering algorithm. The scheduling module 130 is configured to schedule the roadside units located in the hot spot area range to work according to the plurality of hot spot areas in each preset time period. The device 100 of the embodiment of the invention can regulate and control the working state and the dormant state of the roadside unit in a specified time period on the premise of not influencing the connection and the service quality, thereby improving the utilization rate of energy resources of a vehicle-mounted network.
It should be noted that the explanation of the embodiment of the method for deploying and scheduling roadside units in an urban vehicle-mounted network is also applicable to the apparatus for deploying and scheduling roadside units in an urban vehicle-mounted network of the embodiment, and is not described herein again.
According to the arrangement and scheduling device for the roadside units in the urban vehicle-mounted network, the total energy consumed by the whole roadside unit system is ensured to be as small as possible through the arrangement and scheduling of the roadside units, the service performance of the vehicle-mounted network is ensured through the arrangement of the roadside units and the consideration of priority and uniformity, the roadside units are effectively scheduled aiming at the problem of uneven distribution of traffic flow in different areas in different time periods through the identification of hot spot areas, and therefore the working state and the dormant state of the roadside units are regulated and controlled in a specified time period on the premise of not influencing connection and service quality, and the energy resource utilization rate of the vehicle-mounted network is improved.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (5)

1. A deployment and scheduling method of roadside units in an urban vehicle-mounted network is characterized by comprising the following steps:
step S1, selecting a plurality of target intersections in the target area range according to the preset priority of each intersection, and deploying a plurality of roadside units according to the target intersections;
step S2, identifying a plurality of hot spot regions in each preset time period within the target region range according to a density-based clustering algorithm, wherein the step S2 further includes:
step S21, dividing the longitude span and the latitude span of the target area into a span sections, wherein the span of each span section is b, so as to divide the target area into a grid units U (k) with the size of b × b, wherein a, b and k are positive integers;
step S22, obtaining grid density of each grid unit U (k) according to the GPS data points mapped to each grid unit U (k) in each preset time period
Figure FDA0002760815630000011
Step S23, finding out the grid density in each preset time period
Figure FDA0002760815630000012
All grid cell sets Q oftIdentifying and obtaining a plurality of hot spot areas in each preset time period according to the density-based clustering algorithm; and
step S3, scheduling the roadside units in the hot spot area range to work according to the plurality of hot spot areas in each preset time period, wherein the step S3 further includes:
step S31, setting the search radius of the density-based clustering algorithm as epsilon and the neighborhood density threshold as MinPts, and initializing the hot spot region set S in each preset time periodtIf the time is empty, the following steps are executed in each preset time period;
step S32, label set QtAll grid cells in the grid are unsearched grid cells;
step S33, from the set QtArbitrarily select one unsearched grid cell u (k), and perform steps S34 to S37;
step S34, marking the un-searched grid unit U (k) as the searched grid unit, if there are at least MinPts sets Q in the search radius range of the searched grid unit U (k)tThen a hot spot area is created
Figure FDA0002760815630000013
And adding the searched grid cell U (k) to
Figure FDA0002760815630000014
Performing the following steps; otherwise, marking the noise points as noise points;
step S35, search the radius range of the grid unit U (k) in the set QtAdding other grid cells in the set N, and executing the step S36 on each unsearched grid cell U (k') ∈ N in the set N;
step S36, marking the unsearched grid cell U (k ') as a searched grid cell if U (k') Has at least MinPts sets Q within the search radiustThen these elements are added to the set N; if said U (k') does not belong to StIn any hot spot area, add U (k') to
Figure FDA0002760815630000023
Performing the following steps; otherwise, marking the noise points as noise points;
step S37, until Q is collectedtAll grid cells in the set are searched, and the set of hot spot areas in the preset time period is St；
Step S38, initializing all the deployed roadside units to be in a dormant state, and collecting the hot spot areas StEach hot spot region of
Figure FDA0002760815630000021
If deployed roadside unit vR_iIn the hot spot region
Figure FDA0002760815630000022
And if the roadside unit is within the range, setting the roadside unit to be in a working state.
2. The city vehicle-mounted network roadside unit deployment and scheduling method of claim 1, wherein the step S1 further comprises:
step S11, set the target crossroad VRIntersection set C covered by roadside unitsRAre all initialized to null;
step S12, arranging each intersection in descending order according to the preset priority of each intersection;
step S13, judging the CRWhether each intersection is covered, if not, executing the steps S14 to S17 in a loop;
step S14, converting the VRIs given to a preset target intersection set TVRAnd mixing said CRIs assigned to the intersection set TC covered by the preset roadside unitR；
Step S15, selecting the intersection v with the highest preset priorityiWherein v isi∈V-VRAnd V is the set of all crossroads, and the crossroad V is judgediWhether a preset condition is met, if so, VRTo which said v is addediSaid C isRAdding set CR(vi)，CR(vi) And step S16 is executed for the covered intersection set of the roadside units deployed for the ith intersection, if the covered intersection set is not met, intersections meeting preset conditions are sequentially found according to the descending order of the preset priority of each intersection, and step S15 is executed, wherein the preset conditions are intersections viIs out of CRWithin the range;
step S16, for intersection vlWherein v isl∈CR(vi)-TCRIf p isi-plWithin the range of the preset threshold value, reserving the intersection vlAnd proceeds to step S17, otherwise the intersection v is discardedlContinuing to step S16 if TCR∪CR(vl) The number of elements in the set is more than CRThe number of elements in the set is reserved for the intersection vlAnd proceeds to step S17, otherwise, proceeds to step S16, where the intersection viIs recorded as piSaid intersection vlIs recorded as pl；
Step S17, at all vl∈CR(vi)-TCRAfter all the determinations are finished, the step S16 is ended, and TC is selectedR∪CR(vl) Set corresponding maximum crossroad vl，
Step S18, set VRReplacement as TVR∪vlSet C ofRReplacement by TCR∪CR(vl) End step S14 to finish VRThe roadside unit corresponding to each target intersection included in (1).
3. The method for deploying and scheduling roadside units in an urban vehicle-mounted network according to claim 2, wherein the calculation formula of the preset priority is as follows:
pi＝fi veh×wveh+fi con×wcon，
wherein the content of the first and second substances,
Figure FDA0002760815630000031
Xvehfor the set of original values of the influence factors of the density of the traffic flow at all intersections, min (X)veh) A set of representations XvehMinimum value of middle element, max (X)veh) A set of representations XvehMaximum value of middle element, XconIs the set of the original values of all intersection connectivity impact factors, min (X)con) A set of representations XconMinimum value of middle element, max (X)con) A set of representations XconThe maximum value of the medium element.
4. The method for deploying and scheduling roadside units in urban vehicle-mounted network according to claim 3, wherein two impact factors fi vehAnd fi conThe occupied weights are respectively marked as wvehAnd wconWherein w isveh+wcon＝1。
5. The city vehicle-mounted network roadside unit deployment and scheduling method of claim 1, wherein the step S23 further comprises:
if the grid cell does not satisfy the grid density
Figure FDA0002760815630000032
The grid cell is marked as a noise point.
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