Fault tree analysis for the intelligent vehicular networks

Intelligent Vehicular Networks (IVN) or vehicular ad hoc networks (VANET), a subset of Mobile Ad hoc Networks (MANETs), is a wireless communication technology applied to transportation, referring to a set of smart vehicles used on the road. These vehicles provide communication services among one another (V2V) or with Road Side Infrastructure (V2I). The main benefits of VANET are enhancing road safety, reducing energy use and emissions, and giving information services. Reliability is one of the most critical issues related to VANET since the information transmitted is distributed in an open access environment. We focused in this paper on the reliability of VANET as a function of reliable hardware and their functionality while taking into consideration the needed security equipment. Reliability block diagrams (RBD) and fault tree (FT) were used to analyze the reliability of the vehicles and the road side equipment (RSU). In order to prove our results, a simulation was done using RBD and FT probability to validate the proposed approach. The data (failure ratio) used was extracted from professional databases related to the components presented in the system. Our scientific approach was structured with methods that combine qualitative approaches (such as functional analysis, failure modes and effects analysis (FMEA), etc...) and quantitative methods (fault tree, probabilistic models of degradation, etc...) for the VANET. From this data an exponential model of reliability was proposed. The probability calculation was performed in relation to a reference time of use. Thereafter, a sensitivity analysis was suggested concerning the reliability parameters and redesign proposals were developed for the components.