A list,

With the development of intelligent transportation system, vehicle AD hoc networking (VANET) has become a popular network communication technology in this field. Vehicle-mounted network is a special private network formed by wireless communication and data transmission technology, serial vehicles and roadside traffic facilities, which is a highly customized mobile casual network. The main function is to enable all users to obtain and transmit traffic related information in real time, so as to improve driving efficiency, enhance road safety and comfort.

In vehicle-mounted networks, especially in urban environments, high-speed vehicle movement leads to frequent changes in network topology, uneven distribution of vehicle density, and frequent occurrence of sparse connectivity and local optimization. Therefore, a routing protocol with robustness, reliability and real-time performance must be specially designed for vehicle-mounted AD hoc networks. This chapter in view of the existing vehicle collision problems of the urban environment, use of vehicle location and navigation electronic maps provided by the road traffic information make routing decisions, according to a set of urban traffic network simulation diagram, the distribution of the random traffic node, through cross intersection collision research as well as the relative position between the side of the road node warning simulation, The results of urban traffic information network under different simulation are obtained, which has certain guiding significance for the traffic communication design and road condition information improvement in this region.





VANET has the following characteristics:

(1) In VANET network, vehicle node mobility is fast, road topology changes quickly, and path life is short;

(2) The network management of VANET involves a wide range of areas, but it is difficult to maintain connections such as road and mutual configuration between vehicles.

(3) The random distribution of nodes in VANET network is strong, resulting in not very uniform distribution of nodes;

(4) VANET network link is unstable and sensitive to obstacles;

(5) Through self-organizing communication between vehicles, VANET network enables drivers to obtain driving information and real-time road condition information of other vehicles beyond the visual range, so as to help vehicles adjust driving routes in time, realize dynamic road force selection and improve driving efficiency.

(6) Through the information interaction between vehicles and roadside nodes, VANET network can summarize the collected information to the traffic control center for analysis and processing, and feedback the results to drivers.

(7) VANET network is driving safety warning. VANET can warn drivers of a traffic jam or crash in real time, and when the car in front is slowing down, it can also warn the car behind to slow down to avoid a collision.







1 Hybrid Communication (HVC)



Ii. Source code

clc,clear,close all
warning off
im = imread('y4.jpg');
figure(1),
imshow(im)
hold on
load('node_AP.mat')% node coordinatesload('adj_node.mat')% adjacency matrixplot(node_AP(:,1),node_AP(:,2),'sr')
nconx = size(adj_node);
for i=1: nconx(1.1)
    for j=1:nconx(1.2)
        if adj_node(i,j)==1
            xconx=[ node_AP(i,1), node_AP(j,1)];
            yconx=[ node_AP(i,2), node_AP(j,2)];
            plot(xconx,yconx,'b-'.'linewidth'.2);
            % pause(1)
        end
    end
end
n=length(adj_node);
x1(n,n)=0;
for i=1:n
    for j=i:(n- 1)
        x1(i,j+1) =sqrt((node_AP(j+1.1)-node_AP(i,1)). ^2+(node_AP(j+1.2)-node_AP(i,2)). ^2);
    end
end
x2=x1'; x3=x2+x1; % Distance between all roads x4 = x3.* adj_node; % Determines whether the node is connectedfor i=1:n
    for j=1:n
        if x4(i,j)==0x4(i,j)=inf; End end T=prim(x4) % return minimum tree model nT=size(T); figure(2),
imshow(im)
hold on
for i=1:nT(1.2)
    xT=[node_AP(T(1,i),1), node_AP(T(2,i),1)];
    yT=[node_AP(T(1,i),2), node_AP(T(2,i),2)];
    plot(xT,yT,'r-'.'linewidth'.2); End %% maximum short circuit problem figure(3)
imshow(im);
hold on
for i=1:n
    text(node_AP(i,1) +35,node_AP(i,2) +20,num2str(i),'Color'[1 0 0])
end
% for i=1: nconx(1.1)
%     for j=1:nconx(1.2)
%         if adj_node(i,j)==1
%             xconx=[ node_AP(i,1), node_AP(j,1)];
%             yconx=[ node_AP(i,2), node_AP(j,2)];
%             plot(xconx,yconx,'b-'.'linewidth'.2);
%             % pause(1)
%         end
%     end
% end
Copy the code

3. Operation results





Fourth, note

Version: 2014 a