Automated and coordinated vehicles' driving (platooning) is very challenging due to the multi-body control complexity and the presence of unreliable, time-varying wireless Inter-Vehicular Communication (IVC). We propose a novel controller for vehicle platooning based on consensus and analytically demonstrate its stability and dynamic properties. Traditional approaches assume the logical control topology as a constraint fixed a priori, and the control law is designed consequently; our approach makes the control topology a design parameter that can be exploited to reconfigure the controller depending on the needs and scenario characteristics. Furthermore, the controller automatically compensates outdated information caused by network losses and delays. The controller is implemented in PLEXE, a state of the art IVC and mobility simulator that includes basic building blocks for platooning. Analysis and simulations show the controller robustness and performance in several scenarios, including realistic propagation conditions with interference caused by other vehicles. We compare our approach against a controller taken from literature, which is generally considered among the most performing ones. Finally, we test the proposed controller by implementing the real dynamics (engine, transmission, braking systems, etc.) of heterogeneous vehicles in PLEXE and verifying that platoons remain stable and safe regardless of real life impairments that cannot be modeled in the analytic solution. The results show the ability of the proposed approach to maintain a stable string of realistic vehicles with different control-communication topologies even in the presence of strong interference, delays, and fading conditions, providing higher comfort and safety for platoon drivers.
Wireless Community Networks (WCNs) are created and managed by a local community with the goal of sharing Internet connections and offering local services. This paper analyses the data collected on three large WCNs, ranging from 131 to 226 nodes, and used daily by thousands of people. We first analyse the topologies to get insights in the fundamental properties, next we concentrate on two crucial aspects: i) the routing layer, and ii) metrics on the centrality of nodes and the network robustness. All the networks use the Optimized Link State Routing (OLSR) protocol extended with the Expected Transmission Count (ETX) metric. We analyse the quality of the routes and two different techniques to select the Multi-Point Relay (MPR) nodes. The centrality and robustness analysis shows that, in spite of being fully decentralized networks, an adversary that can control a small fraction of carefully chosen nodes can intercept up to 90% of the traffic. The collected data-sets are available as Open Data, so that they can be easily accessed by any interested researcher, and new studies on different topics can be performed. WCNs are just an example of large wireless mesh networks, so our methodology can be applied to any other large mesh network, including commercial ISP networks.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.