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Ethernet is the hottest candidate for future in-car communication architecture, promising much higher bandwidth, flexibility and reduced costs. In the coming years, Ethernet will likely evolve from a separate communication medium for special applications like surround-view cameras and infotainment to a central communication infrastructure as a backbone technology. To make this transition, many difficult design decisions have to be made in order to make the technology suitable for the stricter time and safety requirements of todays and future cars. There are a lot of potential real-time effects that must be taken into account. To guide these design decisions, it is necessary to analyze the various architecture concepts with respect to load, performance and real-time capabilities. In this paper, we present different design space axes of Ethernet and propose a methodology of assessing and comparing them.

High-performance computer architectures for advanced driver assistance systems have become increasingly important in automotive research in the last several years. In order to achieve an optimal and robust perception of the vehicle's surroundings, current driver assistance applications typically rely on multiple sensor systems that deliver large amounts of incoming data from different sensor types. Such sensors include optical systems, which consist of a multi-camera setup combined with complex preprocessing algorithms. These algorithms exhibit high computation and data transport demands, as real-time image processing of multiple input streams is a mandatory requirement for these systems. At the same time, however, future driver assistance systems must adhere to strict power consumption requirements and automotive cost constraints in order to be considered for integration in series vehicles.

Vehicle communication networks are challenged by increasing demands for bandwidth, safety, and security. New data is coming into the vehicle from personal devices (e.g. mobile phones), infotainment systems, camera-based driver assistance, and wireless communication with other vehicles and infrastructure. Ethernet (IEEE 802.3) provides high levels of bandwidth and security, making it a potential solution to the challenges of vehicle communication networks. However, in order to be used in control applications, Ethernet must provide known timing performance (e.g. bounded latency and jitter), and in some cases redundancy. This paper explores use of Ethernet for in-vehicle control applications.

Due to the increasing integration of safety-critical functionalities into electronic devices, safety-related system design and certification have become a major challenge. Amongst others a suitable reaction of components in case of internal errors must be ensured in order to prevent a function from failing and to guarantee a certain degree of reliability. In this context a wide variety of different fault tolerance mechanisms have been developed in the past, including analytical considerations of error coverage and resulting reliability. However, most of these mechanisms induce a certain timing overhead, which in turn might affect the real-time capabilities of the system in a negative way. More concretely, even if each error is treated adequately such that no logical failure occurs, a timing failure due to missing a deadline cannot be ruled out definitely.

The topic of timing has already been recognized as a major challenge when designing safety-critical automotive architectures. Consequently the availability of appropriate performance and timing analysis methods is key to building reliable automotive electric and electronics (E/E) and software architectures. Due to the potential performance increase, power reduction and cost-efficiency multicore solutions for automotive real-time environments receive growing attention. But the prediction of the timing behavior for multicore electronic control unit (ECU) systems becomes more complicated. Even in setups with static task-to-processor mapping, the execution of the tasks is usually not independent. The use of the same physical hardware, such as memories, coprocessors, or network components, makes inter-core interference unavoidable and may introduce hard-to-find timing problems including missed deadlines that can finally make the entire system fail.

Ethernet could be a promising solution to satisfy the increasing bandwidth requirements of future automotive systems. While the non-deterministic timing behavior of standard Ethernet makes its application unsuitable for time critical systems, different real-time Ethernet solutions which ensure bounded communication delays exist and are also already employed in the industry. A common aspect of the existing solutions is the full duplex switched Ethernet network architecture on which they are based. This makes it possible to guarantee the existence of an upper bound of the message latency, but the determination of this bound is far from trivial in most cases. For the determination of the message latency, the behavior of all sources of traffic on the network has to be taken into account. Specifically, one must consider the maximum frame size transmitted by any device, the scheduling parameters of the frames (e.g.

Systems and network integration is a major challenge, and systematic analysis of the complex dynamic timing effects becomes key to building reliable systems. Very often, however, systematic analysis techniques are (considered) too restrictive with respect to established design practice. In this paper we present lessons learned from real-world case studies, in which OEMs have used the new SymTA/S scheduling analysis technology to evaluate different network choices with minimum effort. Thanks to its flexibility and supplier independence, SymTA/S can be applied in non-ideal situations, where other, more restricted technologies are inherently limited. Finally, we put the technology into relation with ongoing standardization activities.