Research On Routing Algorithm For VANET In Three-Dimensional Scenario

With the development of communication technology and the increase in the number of vehicles,the Vehicular Ad-hoc Networks(VANETs)have become a research hotspot in the field of intelligent transportation,attracting more and more attention from research institutions and researchers.In three-dimensional(3D)VANET scenario,dynamic vehicles,complex node distribution and severe path loss increase the probability of link interruption significantly,which deteriorates the reliability of routing algorithms.However,for the key issues of relay sequence selection in the routing process,existing algorithms analyze wireless link performance without considering the influence of dynamics and shadow fading on location information from GPS,as well as channel condition and buffer queue,which leads to inaccurate link characterization and can’t adapt to the network topology variation.Therefore,aiming at solving these above problems,in the 3D VANET scenario,a dynamic link model is established to portray the link reliability,and a link reliability-based adaptive routing algorithm is proposed to improve the packet delivery ratio and end-to-end delay.Firstly,to achieve accurate characterization of wireless link performance in 3D VANET,a kalman filter-based estimation algorithm is adopted to correct the GPS original data to obtain more precise location information of vehicle and its neighbors,and then a 3D VANET dynamic link model is established to evaluate link reliability,which integrates the network characteristics of vehicle mobility,distribution hierarchy and shadow fading into the modeling of SINR,link availability,and buffer queue parameters.Then,to improve the reliability of data transmission in 3D VANET,based on the above dynamic link model,a link reliability-based adaptive routing algorithm is proposed.Considering the different link states among vehicles in the network,the link reliability values are also different.An adaptive maximum deviation method is designed to calculate the weight of each link evaluation attribute,which is used to calculate the link reliability for each link.Based on the above works,the routing relay selection problem of 3D VANET is formulated into a multi-attribute decision making problem,which finds the link sequence with the highest link reliability value as the optimal transmission path.Finally,the algorithm is simulated with NS3 to evaluate the effects of vehicle density,network load and vehicle speed on the routing algorithm.Simulation results demonstrate that our algorithm outperforms the existing routing algorithms in terms of average end-to-end delay and packet delivery ratio,and the packet delivery ratio has a performance improvement of 15% to 30%,which achieves more reliable vehicle communication.