Investigating the Impact of Energy-Efficient Ethernet on Automotive Applications via High-level Modeling

The increasing amount of bandwidth-intensive applications of modern vehicles overstrains traditional field buses and prompted the industry to consider alternative physical layers, most prominently Ethernet. Developed for consumer requirements, stringent constraints regarding energy consumption are hard to fulfill with standard Ethernet. An alternative is an Ethernet incarnation called Energy-Efficient Ethernet (EEEthernet). The savings on energy are achieved by a special sleep and wake-up pattern that, however, may seriously impact the timing behavior of applications. This paper presents a high-level virtual prototyping approach that models EEEthernet within a SystemC-based simulation framework. The energy consumption as well as the timing properties of EEEthernet are encapsulated using the concept of power state machines. By embedding the model in a complete model of the E/E architecture including sensors, actuators, ECUs, and other network systems, the system-wide implications of EEEthernet are analyzed in order to guide further design steps. The results show that for typical automotive applications, EEEthernet can tremendously decrease the consumed energy of the link without harmful effects on the timing. But, especially in case of time-critical and spontaneous control loops, guaranteeing a maximum delay requires a careful consideration of the additional wake-up time of EEEthernet.