Can Automotive Ethernet contribute to the vehicle weight-loss plan?

November 02, 2020 //By Klaus Neuenhüskes, Toshiba Electronics Europe
Can Automotive Ethernet contribute to the vehicle weight-loss plan?
The automotive cable harness is regularly claimed to be the third heaviest component in the vehicle, as well as the third most expensive. It combines a multitude of power cabling, standardised in-vehicle networks, and wiring for proprietary network protocols or bus systems. Without making substantial changes to the vehicle’s E/E Architecture, the only remaining approach to reducing weight is to move away from copper wiring to lighter alternatives.

Today, high-strength aluminium alloy is one of the alternatives employed but merely focusing on reducing the weight of the existing cable harness is only kicking this problem further down the road. The harsh reality is that a lot of the data being transferred around the vehicle could be transported over a simple high-speed twisted-pair connection. Features such as reverse parking cameras often require dedicated cabling for a point-to-point connection to the appropriate electronics control unit (ECU). However, such point-to-point solutions merely serve to enable a desirable consumer feature in a manner that meets a suitable price point, rather than delivering a technology solution that could be expanded to support a wide range of in-vehicle data transport needs.

Is Ethernet the answer?

Ethernet as a technology has been in consideration as an alternative for a long time. Its ubiquity is such that one questions why Ethernet has not been integrated into the vehicle, rather than why it should be. It is well understood, it is integrated into a wide range of microcontrollers (MCU) and system-on-chip (SoC) devices, and there is ample software available, both commercial and open source. Furthermore, the engineering community already has ample understanding with regard to its implementation and fulfilling regulatory compliance.

As more and more data are generated in the vehicle to support advanced driver-assistance systems (ADAS) and autonomous driving, Ethernet seems to be the obvious choice for transporting data from radar, LiDAR and the multitude of cameras such systems require. Certainly, the bandwidth requirement is fulfilled. Unfortunately, classic Ethernet falls down when it comes to supporting applications with time-critical or safety-critical needs, since there are no mechanisms for time-sensitive networking, traffic shaping, or time synchronisation across the network. To support such requirements, changes in the lower layers of the OSI model need to be made.

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