Opportunistically-assisted parking search: A story of free riders, selfish liars and bona fide mules

In competitive autonomic networking environments, user nodes face a strategic dilemma: on the one hand, they need to cooperate to support the networking infrastructure and information flow; on the other hand they are tempted not to do so, e.g., in order to conserve own system resources or create an advantage for themselves. In this paper we investigate a real-world scenario of parking assistance service that instantiates such environments. Under the nominal (altruistic) operation, the vehicles opportunistically collect and share information on the location and availability status of the parking spots they encounter. Yet the competition for parking spots may give rise to various facets of misbehaviors, such as deferring from sharing their information (free riders) and/or deliberately falsifying disseminated information so as to divert other drivers away from a particular area of own interest (selfish liars). Simulation results indicate a persistent fate-sharing effect, i.e., misbehaving nodes fail to obtain any substantial performance advantage that would indeed motivate their misbehaviors. Furthermore, the overall performance of the system does not necessarily deteriorate as the intensity of misbehaviors increases. Misbehaviors rather tend to reduce the distance between the destination and the actual parking spot occupied for all vehicles at the expense of higher parking search times, which quickly become prohibitive when the vehicles' destinations overlap. Finally, the addition of mobile storage nodes (bona fide mules) compensates for the reduction of the information flow due to free riders but has almost no effect against selfish liars since the mobile storage nodes end up propagating the falsified information those nodes generate.