Periodical Broadcasts of individual vehicles safe ty information such as velocity and acceleration are critical in Vehicular Ad-Hoc Networks (VANETs).However,current contention-based Media Access Control (MAC) protocols cannot guarantee high performance in high density VANETs.In this paper,we propose a MAC protocol based on the s-disjunct code to achieve reliable and realtime broadcasts via assigning a channel to each vehicle as the vehicle enters the network.Our protocol is adaptive as vehicles are required to adjust their communication ranges according to the network density in order to avert the interference among thCm.Wc conduct an extensive simulation study,and our results indicate that the proposed scheme can successfully achieve the requirements of the Dedicated Short Range Communication (DSRC) standard,i.e.,to broadcast safety information 10 times per second.Even at a high vehicle density,our scheme still guarantees that the success rates of both transmission and reception are greater than 95%, and the collision rates of access collision and merging collision are lower than 10 collisions/period.
VANETs s-disjunct code MAC Communication range control
Chao Wang Xiumei Fan Jiguo Yu Kai Xing Yingwen Chen Jiawei Liang
School of Computer Science,Beijing Institute of Technology,Beijing,100081,China School of Automation and Information Engineering,Xian University of Technology,Xian,Shaanxi,710048 School of Information Science and Engineering,Qufu Normal University,Rizhao,Shandong,276826,P. R. Ch School of Computer Science and Technology,University of Science and Technology of China,HeFei,Anhui, College of Computer,National University of Defense Technology,Changsha,Hunan,410073,China School of Optoelectronics,Beijing Institute of Technology,Beijing,100081,China