Heterogeneous Vehicular Communications:VANET-DSRC And VANET-5G Data-Rate Adaptation Approach

In recent years,vehicular communications have become an intensive research area as a vital part of the Intelligent Transportation System(ITS).VANET is an emerging area of wireless ad-hoc networks to increase traffic safety and comfort.The extremely changeable number of mobile nodes and high mobility are challenging issues.Besides,message dissemination is a serious subject in road safety and traffic efficiency.These problems cause dramatically degradation in wireless network performance.Hence,the heterogeneous vehicular network,which integrates cellular networks with DSRC,has been proposed and attracted significant attention.VANET-cellular integration provides several potential benefits,for instance,high data rates,more communication range,and low latency.Moreover,VANET heterogeneous wireless networks integration will significantly help autonomous cars to be functional in reality.On the other hand,this particular network has several problems in term of defining suitable schemes and protocols like rate adaptation mechanisms.The overall performance of diverse VANET applications like traffic control,management,and multimedia delivery is based on the achievement ratio these networks can offer and the network throughput.IEEE 802.11 p is a key enabling technology to support vehicular safety applications.Rate Adaptation is a fundamental mechanism in 802.11 systems in order to achieve the best possible performance,by predicting the prevailing channel conditions and deciding appropriate transmission rate quickly based on channel status.Despite there are many available rate adaptation algorithms for 802.11 WLANs standards,there are few works devoted to the rate adaptation for the vehicular network standard.Besides,existing rate adaptation solutions may not be suitable for vehicular safety communications in some scenarios.This thesis addresses a data rate approach for heterogeneous vehicular communications.First,we review some associated works in the literature dealing with heterogeneous vehicular communications in term of vertical handover,gateway selection,data dissemination and collection,and other issues.The comparison between diverse studies is based on characteristics like throughput,packet loss,delay,and bandwidth.Then,we discuss the subject of self-driving cars which is a very hot topic in academia and automobile companies.The collaboration between DSRC and mmWave 5G cellular networks in VANET-heterogeneous wireless networks integration will significantly help autonomous cars projects.Moreover,we evaluate and compare the existing rate adaptation schemes in numerous vehicular scenarios to understand their behavior and analyze their performance in diverse environments.The selected algorithms for comparison using the NS-3 simulator are ARF,AARF,AMRR,AARF-CD,CARA,Ideal,Minstrel,and Onoe.The simulation outcomes demonstrate that Minstrel algorithm has the best performance in dense and dynamic situations when compared with the remaining mechanisms.Finally,we propose an optimized rate adaptation algorithm,called Drive Z-Minstrel(DZ-Minstrel),for 802.11 p heterogeneous vehicular networks.We evaluate and compare our algorithm with the previously mentioned algorithms in various vehicular scenarios.Simulation results show that DZ-Minstrel consistently outperforms the existing rate adaptation schemes,particularly in dynamic and dense scenarios.DZ-Minstrel algorithm resulted in higher throughput and more received packets by RSU,compared to the other tested algorithms.