A Trust Model for Intervehicular Communication Based on Belief Theory

Vehicles will exchange much information in the future in order to efficiently maintain their inner model of the environment. Before they can belief received pieces of information, they must evaluate their reliability. Trust is a mechanism to estimate this reliability based on the sender. As cars often drive the same route, they meet each other again and again. They can establish friendship-like relations and thus are embedded in a social structure. A trust model depends on this social structure. For this reason, we simulate the driving pattern of a small town. Within this simulation, all cars are equipped with a trust model that continuously monitors the experiences made with others. The developed model focuses on direct experiences of the individual and not on a system-wide reputation which would depend on a central unit. It continuously evaluates the performance and reputation of other cars and includes a feedback loop to faster adapt to changes in the other's behaviour. To make a decision out of the collected data, the model uses the capacity of the binary error and erasure channel from information theory. This capacity provides a better decision criterion than the traditional expectation value. The proposed trust model is an individual-level model; nonetheless it can be connected to a system-wide reputation mechanism.