1 Introduction

Most vehicles on the road today use a domain architecture, in which electronic control units (ECUs) and the associated cabling are grouped by function, such as powertrain, body, infotainment, or ADAS. The industry is moving toward a zonal architecture, in which functions are grouped by physical location in the vehicle. Zonal modules aggregate the sensors and actuators in an associated area and connect to a central vehicle compute node over a high-speed Ethernet backbone. This architecture reduces the number of ECUs and the length of the wiring harness. The architecture also enables over-the-air (OTA) software updates to vehicle functions, which is the foundation of the software-defined vehicle (SDV) and the path toward higher levels of driving automation.

In this architecture, the central compute combines data from several radar sensors, and from cameras and other sensors, which are connected over Ethernet. Two requirements follow:

1. The data must be time-aligned. The central processor fuses data from several radars, and from cameras and other sensors. The fused result is only correct if every measurement describes the same moment in time. This depends on all sensors sharing a precise common time base, which IEEE 802.1as distributes over the Ethernet network.
2. The data must be trustworthy. Radar data travels over Ethernet cables that run through the vehicle; a central perception stack that makes braking and steering decisions must be able to verify that the data comes from the real sensor and has not been altered, replayed, or read in transit. IEEE 802.1AE MACsec provides this protection at the link layer.