Christoph Sommer

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Recently, many efforts have been made to develop more efficient Inter-Vehicle Communication (IVC) protocols for on-demand route planning according to observed traffic congestion or incidents, as well as for safety applications. Because practical experiments are often not feasible, simulation of network protocol behavior in Vehicular Ad Hoc Network (VANET)(More)
We present a realistic, yet computationally inexpensive simulation model for IEEE 802.11p radio shadowing in urban environments. Based on real world measurements using IEEE 802.11p/DSRC devices, we estimated the effect that buildings and other obstacles have on the radio communication between vehicles. Especially for evaluating safety applications in the(More)
Efficient data management techniques are needed in Wireless Sensor Networks (WSNs) to counteract issues related to limited resources, e.g. energy, memory, bandwidth, as well as limited connectivity. Self-organizing and cooperative algorithms are thought to be the optimal solution to overcome these limitations. On an abstract level, structured peer-to-peer(More)
Coupling Vehicular Ad Hoc Networks (VANETs) with wired networks such as the Internet via access points creates a difficult mix of highly mobile nodes and a static infrastructure. In order to evaluate the performance of typical ad hoc routing protocols—in particular, we used Dynamic MANET On Demand (DYMO)—in such VANET scenarios, we combined microsimulation(More)
Traffic Information Systems (TIS) are one of the key non-safety application areas of Vehicular Ad Hoc Networks (VANETs). As such, TIS are much less delay sensitive compared to safety applications, which have recently attracted a lot of attention in VANET research. We propose a new message dissemination protocol, Adaptive Traffic Beacon (ATB), which is fully(More)
Much progress can be observed in the domain of Vehicular Ad Hoc Network (VANET) research looking back at the last decade. It can be seen that studies of vehicular communication protocols in the context of VANETs are typically based on simulation models. This approach has two major prerequisites: First, detailed network simulation of all layers of(More)
Experimental research on wireless communication protocols frequently requires full access to all protocol layers, down to and including the physical layer. Software Defined Radio (SDR) hardware platforms, together with real-time signal processing frameworks, offer a basis to implement transceivers that can allow such experimentation and sophisticated(More)
We study the effectiveness of Inter-Vehicle Communication (IVC) in urban and suburban environments at low node densities, with a particular focus on cooperative awareness and traffic safety. The recently standardized DSRC/WAVE protocol suite defines a platform for such applications, which mainly focus on beaconing, i.e., periodic 1-hop-broadcast. In(More)
We present Adaptive Traffic Beacon (ATB), a fully-decentralized car-to-X protocol built around the central ideas of delay sensitivity and congestion awareness. From previous research findings, we see that centralized solutions, VANETs, and broadcasting based approaches each show benefits and drawbacks depending on traffic density, penetration, network(More)
Simulation of network protocol behavior in Vehicular Ad Hoc Network (VANET) scenarios is strongly demanded for evaluating the applicability of developed network protocols. In this work, we discuss the need for bidirectional coupling of network simulation and road traffic microsimulation for evaluating such protocols. The implemented mobility model, which(More)