Research On Theory And Technology Of Hybrid Communications In Vehicular Ad-hoc Networks

VANET（Vehicular Ad-Hoc Network）concentrates on the mobile vehicles and theapplications running on them, therefore it requires a more strict network conditions for itstransmission features, so it needs a networking stack specialized for secure and continuousservice access in vehicular environments. And the integration of different heterogeneousnetworks is the main concept and very important specially for middle and long range isimportant due to large-scale distributed vehicles and diverse performance requirements ofvehicular applications. The integration of3G and WLAN has already extended the service forVANET, however traditional wireless coverage is limited,thus blocking vehicular nodes fromInternet to access to services, in this paper we will discuss the integrated architecture ofUMTS (Universal Mobile Telecommunications System) and VANET aiming at addressingthe limitations caused be VANET coverage when accessing to Internet seamlessly byexpanding the previous VANET gateway model which supports connections with UMTScore network,we design scenarios using OPNET and the results are encouraging in terms ofhttp page response time and throughput. We also will discuss the integration ofhigh-bandwidth Wi-Fi technology (e.g.802.11p) and large-scale4G network (e.g. Long-TermEvolution, shortly for LTE) which would make up for each other’s mutual limitations andprovide vehicles ubiquitous Internet available. We propose a novel vertical handoveralgorithm, and a feasible integrated system architecture of heterogeneous802.11p and LTEtechnologies by comparing Received Signal Strength(RSS) from both interfaces. We executeextensive simulations to investigate and analyze the performance of the proposed algorithmand architecture by using NS3. Results show that the proposed architecture displays the highthroughput and low round trip time.