IEEE 802.1AS time synchronization in a switched Ethernet based in-car network

Abstract

As of today Ethernet is used in the in-vehicle network mainly for two use cases: connectivity between the head unit and the rear seat entertainment (RSE) as well as faster onboard diagnostics (OBD). With the increasing bandwidth demand in driver assistance and the wish to easier interconnect the driver assistance and infotainment domains additional usage of Ethernet in the vehicle is being examined. The legacy Ethernet does only provide very limited Quality-of-Service (QoS) mechanisms so that demanding real-time in-vehicle applications cannot meet their constraints. The Audio/Video Bridging (AVB) group introduced several IEEE standards to allow audio and video applications with high QoS demands in a switched Ethernet network. Although these mechanisms were not designed for automotive use cases, they are good extensions to switched Ethernet when QoS demands exist. Therefore, an evaluation of AVB for the usage in in-vehicle networks is needed. In this work, we focus on a base mechanism of the IEEE 802.1 AVB standard, the IEEE 802.1AS time synchronization protocol and its usage in the in-vehicle network. The evaluation is performed by simulation with the network simulation tool OMNeT++ and we modifed the INET-framework with the IEEE 802.1AS capability for our purpose.