Ethernet for Cars?

Ethernet to gain ground in automotive applications, Bosch predicts

Christoph Hammerschmidt

2/5/2011 6:22 PM EST

Having already secured a toehold in diagnostics applications, Ethernet will continue to gain territory in cars. During an industry meeting in Munich, Bosch Automotive Electronics VP Rainer Kallenbach laid out its vision of future in-vehicle networking.

In today's vehicles – or at least in the vehicles currently under design – the electronics landscape is structured in "domains" – for instance, for body electronics, infotainment, vehicle motion management, occupant and pedestrian safety, and energy management. Each domain is controlled by a specific ECU which assumes the role of a central computer for this domain. Domains can in turn be structured into sub-domains. At the top level, they exchange data across a number of different networks, with a Central Gateway controlling the data flow.

Typically, the network technologies used for inter-domain communications are domain specific: The body electronics domain, for instance is connected to the Central Gateway by means of a CAN or High-speed CAN link, whereas in the energy management and in particular in the vehicle motion management domain, FlexRay might be the technology of choice.

In the infotainment domain prevails the MOST bus. Its latest version MOST150 offers ample space for growing bandwidth requirements. Which will be necessary, given the applications currently in the offing which will enter the cars over the next couple of years: In-vehicle infotainment with separate audio and video program for rear seat passengers, personal connectivity, vehicle internet integration or car-to-x connectivity.

In this environment of increasing bandwidth demand and the necessity to dovetail software functions of the car and the outside world, Ethernet as the predominant networking technology in commercial IT will gain ground also in cars. At the same time, communication processes will increasingly use the Internet protocol stack (IP). Currently, the Diagnosis over IP (DoIP) standard is being worked, driven mainly by Audi, BMW and Daimler; a pre-version is implemented in the current BMW 7 series.

On the long run, Ethernet will likely spread to other segments of in-car network, predicted Rainer Kallenbach, Automotive Electronics VP of supplier Bosch, at the Euroforum Automotive Electronics meeting in Munich. "We see Ethernet also as infotainment bus system", Kallenbach said. "In connection with internet connectivity, also IP will enter the cars". Applications are many, Kallenbach mentioned in this context remote diagnosis and location based services enhancing the navigation system functionality.

Examples for applications which drive the bandwidth demand are video systems in the infotainment context where data rates up to 100 Mbit/s accrue. In the vehicle motion and safety domain, video cameras increasingly are deployed. Again, the video streams generate data rates of up to 100 Mbit/s, Kallenbach explained.

In Bosch's scenario, Ethernet will start to offer an alternative to MOST150 beginning around the year 2015. by 2020, it likely will replace MOST. The same holds true for in-vehicle camera applications where first MOST150 will displace the LVDS data transfer technology; later Ethernet could displace MOST150. And in a future architecture characterized by the deployment of domain control units (DCUs) and a backbone connecting these domains, Ethernet will be without alternative from the start which Bosch expects around 2020.

But what about FlexRay – the networking technology designed to replace CAN and High-speed CAN in particular time-critical applications? Will it also be replaced by Ethernet before it really came out of the starting blocks? No, Kallenbach said, FlexRay likely will be able to defend its terrain. But it will be application will be confined to powertrain and vehicle motion management.

This article originally appeared on EE TImes Europe.