Quality of Context for VANETs: QoC Metrics for Connectivity in VANETs

Context describes the status of a system and of the environment in which it operates. In context-aware systems, contextual information is obtained by monitoring the environment with various sensors. Applied to a vehicular network, the context describes the state of the network, considering its various components and requirements for running applications. The context is used by the network to decide about routing, about fault correction and about recovery and the adequacy of services. This adapts the network to changes that occur in the environment. Due to the high dynamicity of the network, context information changes frequently, and old information should no longer be used for system decisions. It is therefore important that the information collected by the context is presented, along with indications of validity time, adding quality to this information. The validity time of context information is one of the parameters that characterize Quality of Context (QoC). In this article we present a context definition for vehicular networks and QoC parameters for this context. In particular, as QoC parameters we present the validity of the status of communication between pairs of vehicles, the timeliness of this context information, and the confidence, which indicates the reliability of the context. We programmed the context conditions into a simulator to generate results. The results show the efficiency of the context and the QoS metrics, and that these metrics are applicable and provide relative reliability to the context.