Algorithm Research Of Vanet MAC Layer Based On IEEE802.11p

Wit h more and more serious urban traffic jam and traffic accidents, VAN ET has been me nt ioned frequent ly and gradually began to apply. VAN ET is a mobile ad hoc network built by vehic les and roadside access points. VAN ET conta ins wire less network of vehicle to vehic le and wire less network of vehic le to the access point. As VAN ET has important practical s ignificance in intelligent traffic informat ion syste m, it gradua lly developed into a popular fie ld of research.VAN ET take car node as it’s communicat ion unit. Beacaus of t he limit of road, car node’s locatio n and communicat ion are influenced by traffic. Car nodes move fast and communicate unsteadily. How to ensure vehic le networking me mbers in high dyna mic topology and compet it ive environme nt can access wire less channe l has been a VAN ET hotspot.This article focuses on the analys is of IEEE802.11 p standard MAC layer protocol for VAN ET and propose to study how to comb ine vehic le traffic mobilit y characteristics to optimize MAC protocols.This art icle ana lyzes VAN ET syste m mode l w ith tra ffic mob ility. We can thereby define vehic les into five categories by judging displaceme nt move ment trends between two nodes and provide different channe l access prior ity according to the IEEE802.11 p EDC A mecha nis m. Then we can decrease networking inequit ies caused by node mob ility, and improve network perfor mance.In this artic le nodes are divided into two categories by densit y of vehic le network environment according to the traffic flow theory. Thereby we rewr ite the IEEE 802.11 p DCF mechanis m backoff a lgor ithm for vehicle node judged by different environme nts dens ity. We propose VBA to replace the or iginal binary exponent ia l backoff algorit hm. Thereby, we reduce the possib ilit y of inva lid node backoff under sparse environment and reduce probabilit y of message collis ion under dense environment to improve the network performance.Finally Vanet Mobisim and NS2 simulat ion softwares are chosen to build the simulat ion p latfor m. In the cit y V2 V unicast scenario the two algor ithms are carried out by simulat ion plat form. We compare two improved algor ithms w ith origina l algorit hms in packet loss rate, fa irness, dela y and analyze the reason. Simulat ion results s how that VB A and VEDC A can improve the fair ness of t he network, reduce access dela y, improve network performa nce. Through this research, we provide certain reference for the improveme nt of VAN ET protocols and the connectio n between traffic characterist ics and VAN ET protocols.