Developing Event Based Middleware for Information Dissemination in Vehicular Ad-hoc Networks

Abstract

VANET (Vehicular Adhoc Network) can be defined as a distributed, self organizing communication network of moving vehicles and stationary road side info-stations. These vehicles are equipped with radio interfaces using which they are able to com- municate with any existing infrastructure or among themselves. VANETs can be utilized to disseminate important information items which can assist in providing safe and comfortable driving experience. Efficient and scalable information dissemination remains a major challenge in VANET as communicating nodes may dynamically leave or join the network and availability of any particular node cannot be guaranteed at any given time. There is need of a middleware that can provide asynchronous and decoupled communication mechanisms for robust application development. In this thesis, we propose our approach for developing information dissemi- nation middleware which utilizes publish/subscribe communication paradigm over structured P2P (Peer to Peer) overlay networks. Publish/subscribe communica- tion paradigm is an attractive alternative for designing information dissemination applications in distributed and dynamic environment like VANET. This paradigm provides decoupling in time, space and synchronization between information pro- ducers, called publishers and information consumers, called subscribers.Our approach has been guided by simulation studies performed to understand the trade-offs related to availability of infrastructure and traffic conditions. Depend- ing upon the number of available road side info-stations, three designs have been proposed. In the first design, publish/subscribe framework is implemented over DHT of info-stations. Further, it is also investigated that even if info-stations are not connected to internet, the DHTs formed among them can provide acceptable performance. In second, DHT of city-buses run by public transport is utilized and in third, a 2-tier DHT is proposed which is the hybrid of the first and second de- sign. These designs have been evaluated under different traffic conditions prevailing in urban and semi-urban area and under uniform and skewed vehicle distribution across the roads.