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UBC Theses and Dissertations

Delay, reliability, and trust in information dissemination in vehicular networks Rostamzadeh, Karim


The cost of road accidents globally is more than $500 B every year. Intelligent Transportation Systems (ITS) is a promising solution and Vehicular Networks is an ideal candidate for providing a communication platform for ITS applications. Safety-critical applications form the main motivation for intelligent transportation systems. Studying the major concerns in such applications, i.e., delay and reliability, through mathematical analysis is extremely beneficial because it enables us to design optimized schemes. Such analysis is, however, challenging due to the dynamics of a vehicular network. In this research, we have three main contributions. First, we present a mathematical model to study delay and reliability of emergency message dissemination in vehicular networks. This model includes three modules to address effects of channel, contention, and partitioning on delivery delay. This is the first delay model to the best of our knowledge that does all of these, and it gives network architects insight into the limitations of the network and helps them tune parameters such as transmission power and slot time duration. Simulation studies indicate that our model does capture the delay characteristics of vehicular networks for both highway and urban scenarios. An interesting observation from the analytical model confirms the fact that using the vehicle density on the road is a good metric for setting the right forwarding probability in vehicles. We exploit this conclusion and as our second contribution, we propose a completely distributed forwarding strategy, called Middle Is Next or MIN. Extensive simulations affirm the effectiveness of MIN in terms of delay and single-hop reliability in comparison with other well-known routing methods. Trusted communication in vehicular networks is of crucial importance without which all efforts for minimizing the delay or maximizing the reliability could be voided. As our third contribution, we propose FACT: Framework for Application-oriented Context-aware Trust-based communication in vehicular networks. FACT assigns a trust value to each road segment and one to each neighbourhood, instead of each car. Thus, it scales up easily and is completely distributed. Experimental results demonstrate that FACT outperforms other well-known routing protocols since it routes the messages via trusted paths.

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Attribution-NonCommercial-NoDerivs 2.5 Canada