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The introduction of FlexRay is often motivated with high bandwidth, fail-safety, and deterministic timing. To no surprise, FlexRay is currently being introduced broadly in the chassis domain with its safety-critical, distributed control functions. However, also FlexRay system exhibit unwanted timing effects such as over- and under-sampling and ECU signal jitter. To fully exploit FlexRay’s potential, these effects must be understood, controlled, and reasonably considered in the supply-chain communication. In this paper, we illustrate the key timing pitfalls that exist with FlexRay. We further demonstrate how timing analysis increases confidence and allows thorough optimizations of FlexRay designs. This helps OEMs and Tier-1 suppliers to protect against timing problems early. Parts of the technology are available, however, new methodological steps are needed.

For a long time, tools and methods for automotive E/E design were mostly in the domain of academic researches only. Recently, OEMs have started adopting selected contributions, because (very soon) it will become quite costly NOT to apply them. The first step is establishing centralized data storage for all design data. At present, selecting appropriate abstraction levels and design methods that get fed by and feed the data is the task at hand. In this paper, we summarize recent progress in this selection process with a focus on performance; which is a key aspect for architecture generation. Our contribution provides incremental progress from both ends of the mentioned gap (requirements vs. architecture vs. implementation) towards one another. The presentation is created around the IMES project [21] considering centralized data storage. However, the overall approach is based on established standards and common design patterns as much as possible.

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.

Multi-core systems are promising a cost-effective solution for (1) advanced vehicle features requiring dramatically more software and hence an order of magnitude more processing power, (2) redundancy and mixed-IP, mixed-ASIL isolation required for ISO 26262 functional safety, and (3) integration of previously separate ECUs and evolving embedded software business models requiring separation of different software parts. In this context, designing, optimizing and verifying the mapping and scheduling of software functions onto multiple processing cores becomes key. This paper describes several multi-core task design and scheduling design options, including function-to-task mapping, task-to-core allocation (both static and dynamic), and associated scheduling policies such as rate-monotonic, criticality-aware priority assignment, period transformation, hierarchical partition scheduling, and dynamic global scheduling.

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.

Today, gated networks with several buses are becoming standard in automotive E/E-systems but are evolving differently among the various vehicle manufactures, with different topologies, combinations of bus protocols, and speeds. Making the right architecture decisions requires systematic evaluation of the many alternatives during early design stages. However, there are many trade-offs in terms of performance, cost, extensibility, etc.. In this context, scheduling analysis is a powerful tool. It clarifies performance, end-to-end timing, and dynamic behavior. This enables evaluation of networking alternatives, foresight of bottlenecks, and provides guidance in the design process. In the paper, the application of scheduling analysis in automotive network exploration and optimization will be demonstrated. Specific emphasize will be put on end-to-end timing, migration from CAN to FlexRay, black-box integration and early-stage assumptions, extensibility, and trade-offs.

When designing safety-critical automotive systems, verification of timing and performance are key, especially the verification of hard deadlines and other critical timing constraints. Test- or simulation-based approaches suffer from corner-case coverage problems and are becoming less reliable as systems grow in size and complexity. Time-triggered mechanisms (e.g. OSEKtime and FlexRay) were proposed as a way out by providing better timing prediction. However, for reasons of cost, flexibility and reactivity, future cars will mostly likely contain a mix of event-triggered (ET) and time-triggered (TT) components that are combined synchronously and/or asynchronously, thereby further complicating timing. Scheduling analysis has recently matured to allow reliable timing verification and systematic optimization for ET, TT, and mixed systems.

New technologies such as multi-core and Ethernet provide vastly improved computing and communications capabilities. This sets the foundation for the implementation of new digital megatrends in almost all areas: driver assistance, vehicle dynamics, electrification, safety, connectivity, autonomous driving. The new challenge: We must share these computing and communication capacities among all vehicle functions and their software. For this step, we need a good resource planning to minimize the probability of late resource bottlenecks (e.g. overload, lack of real-time capability, quality loss). In this article, we summarize the status quo in the field of resource management and provide an outlook on the challenges ahead.

The increasing functionality and complexity of future electric/electronic architectures requires efficient methods and tools to support design decisions, which are taken in early development phases 6. For the past four years, a holistic approach for architecture development has been established at Mercedes-Benz Cars R&D department. At its core is a seamless design flow, including the conception, the analysis and the documentation for electric/electronic architectures. One of the actual challenges in the design of electric/electronic architectures concerns communication behavior and network topologies. The increasing data exchange between the ECUs creates high requirements for the networks. With the introduction of FlexRay 21 and Ethernet the automotive network architecture become a lot more heterogeneous. Especially gateways must fulfill many new requirements to handle the strict periodic schedule of FlexRay and the partly event-triggered communication on CAN-busses 23.