Abstract

Nowadays, driver assistance systems involve an ever increasing degree of automatization. Costly effort is put into testing the individual components to ensure proper functioning by the vehicle manufacturers. However, problems can also arise on a macroscopic scale, as vehicles and infrastructure are recently equipped with short range radio communication (“Car2X”). These problems caused by interaction are of even greater concern than “normal” bugs, as the final product might already have been deployed when the issues first become apparent. Multi-Agent System (MAS) research refers to such issues as “emergent misbehavior”. The said field also brought up an approach to automatically discover the worst consequences of the malfunctions. Hence, a given system under test can already be revised during development, saving a tremendous amount of resources. The approach from MAS is adapted to the domain of testing driver assistance systems in traffic simulations. A green-light optimal-speed advisory (GLOSA) algorithm is used as an example in which conceptual problems are discovered by the testing system after simpler issues are eliminated.

Abstract

Vehicular ad hoc networks (VANETs), often called Car2X communication systems, are about to enter the mass market in upcoming years. They are intended to increase traffic safety by enabling new safety critical driver assistance systems. This also means that strong security mechanisms are required to safeguard communication within VANETs. However, standardized security mechanisms lead to significant overhead in terms of data rate requirement and delay. Prior work has focused on reducing the overhead by advanced strategies for pseudonym and authorization authority certificate exchange. However, we find that this is not enough to enable reliable message exchange in VANETs. Various other sources of overhead caused by security mechanisms in VANETs are identified in the provided analysis. Thereby, we find cross layer and cross message dependencies. In combination with the non-fragmentation property of VANET messages, such dependencies are discovered to lead to massive dropping of packets due to maximum size violations at low protocol layers. Thus, we develop a method for cross layer on demand content assembling for VANET messages, which can avoid the size limit violations without preventing individual layers from disseminating their variable length data sets.

Abstract

Wireless intelligent transport systems based on Car-to-X communication technology are about to enter the mass market in upcoming years. Thereby, efficient and reliable security systems are a core point of concern in system design. Currently regarded digital signature schemes using pseudonym certificates can introduce significant overhead into the highly bandwidth restricted system. Thus, mechanisms to optimize the efficiency of the security mechanisms in regard to authentication delay and channel load are required. Prior work has focused on scenarios with high node mobility, e.g., Freeways. However, bandwidth conserving mechanisms are also required for urban low and medium mobility scenarios to enable foreseen extension of the wireless network for the many other volatile road users like pedestrians. Hence, an approach for efficient pseudonym certificate distribution in urban scenarios is provided in this work. The given simulation based environment shows that it can enhance cooperative awareness while limiting used bandwidth. Thus, it can be regarded as well suitable for future urban intelligent transport systems.

Abstract

Car-to-X communication systems, often called vehicular ad-hoc networks (VANETs), are in the process of entering the mass market in upcoming years. Thereby, security is a core point of concern due to the intended use for safety critical driver assistance systems. However, currently suggested security mechanisms introduce significant overhead into Car-to-X systems in terms of channel load and delay. Especially, the usage of on the fly distributed pseudonym certificates leads to a trade off between channel load and authentication delay, which may lead to significant packet loss. Thus, this work studies a novel concept for pseudonym certificate distribution in VANETs using rate-adaptive certificate distribution based on monitoring a vehicle's environment. Thereby, the cyclic certificate emission frequency is adapted on the fly based on cooperative awareness metrics for discrete parts of the vehicle's surrounding. The obtained mechanism is evaluated in a highway as well as an urban simulation scenario to show its suitability for a broad range of traffic conditions. Thereby, we find that it is able to significantly outperform the currently standardized approach for pseudonym certificate distribution in VANETs based on ETSI ITS standards. Thus, it should be regarded for further development of future VANETs.

Abstract

In the invited talk 'Car2x with SDN, NFV and supercomputers' we report about how our past work with SDN [1, 2] allows the design of a smart mobility fieldlab in the huge parking lot the Amsterdam Arena. We explain how we can engineer and test software that handle the complex conditions of the Car2X case. The talk starts by describing the engineering challenges that developers of smart car telecommunications and computing infrastructures face. We concentrate on the development of software defined networks (SDN) that support smart cars optimally and securely over a heterogeneous, dynamic and developing ICT infrastructure. The goal here is to enable smart cars to profit maximally from any bit of information available from fixed and moving objects as well as persons. For example, in a low tech situation, the lack of other options makes that one has to fall back to GPRS to download only traffic jam locations. As a contrast, in an advanced telecom environment video streams from multiple cars are transmitted via 5G pico cells to computers a few millisecond nearby. These computers fuse the video information to generate a local traffic model. In an ultimate situation, cars use all the communications infrastructures that are available including the numerous WiFi hotspots, all generations of mobile telecommunications, the developing car-to-car communications technologies and even the smart phone of a passing person. SDN technologies deal with the complexities of such communication environment. © 2015 IEEE.