Recently, user mobility in wireless data networks is increasing because of the popularity of portable devices and the desire for voice and multimedia applications. These applications, however, require fast handoffs among base stations to maintain the quality of the connections. Re-authentication during handoff procedures causes a long handoff latency which affects the flow and service quality especially for multimedia applications. Therefore minimizing re-authentication latency is crucial in order to support real-time multimedia applications on public wireless IP networks. In this paper, we propose two fast re-authentication methods based on the predictive authentication mechanism defined by IEEE 802.11i security group. We have implemented these methods in an experimental test-bed using freeware and commodity 802.11 hardware and we demonstrate that they provide significant latency reductions compared to already proposed solutions. Conducted measurements show a very low latency not exceeding 50 ms under extreme congested network conditions.
The objective of vehicular communication is to improve road safety and traffic efficiency through a variety of cooperative intelligent transport system (C-ITS) services. These services allow information exchange between vehicles and other communication entities (e.g., vehicles, infrastructure, pedestrians). Many advanced services are envisaged to support autonomous vehicles and safety applications. The performance requirements of such services are considered highly critical for road safety. However, all these services increase the channel load, and thus, it is difficult to differentiate which service has a higher priority for accessing communication channels. In this paper, we focus on the classification of C-ITS services, which allows the cohabitation of all services considering the strict performance requirements for some services. The aim is to classify C-ITS services based on their packet delay requirements in order to define higher priority for critical services to ensure their dissemination, especially under congestion conditions. Then, we present protocols and quality of service (QoS) mechanisms that can map this classification to the available vehicular networks.
INDEX TERMSCooperative Intelligent Transport Systems (C-ITS), Vehicular and wireless technologies, Cellular-V2X, ITS-G5, Vehicle-to-Everything (V2X)
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