Ethernet succeeds in automotive environments

October 14, 2011 // By Christoph Hammerschmidt
Standard IT components and approaches increasingly enter automotive electronics. Now Ethernet is about to be established as the data bus standard for future car generations.

The latest version of the automotive infotainment bus system, MOST 150, has yet to enter the serial production phase, but now Ethernet seems to emerge as a powerful rival. At the VDI congress on automotive electronics in Baden-Baden (Germany), several players launched commitments to Ethernet as a future standard for in-car data communications.

"After years of relative standstill, the field of automotive EE architecture has started to move again", said Helmut Matschi who oversees the Division Interior of automotive supplier Continental AG. "With Ethernet, we anticipate a lot of changes in intra-automotive networking".

During a press roundtable, Matschi explained that the tier one company sees enormous advantages for Ethernet in automotive environments. The networking standard from commercial IT could help to drive down costs without compromising performance or safety. Currently, for high-bandwidth data transmission, automakers have two alternatives: LVDS (Low Voltage Differential Signaling) and MOST. LVDS is fast, but expensive since it requires shielded cables. MOST is also rather fast and its EMC characteristics are undisputedly excellent, but its optical wiring is very expensive and difficult to handle in the car production ("A nightmare", said an engineer familiar to the matter). Ethernet hitherto had a problem: It's EMC characteristics was not as good as it should be as long as cheap UTP cable was used, and shielded twisted pair was not cost effective.

The Ethernet Physical Layer for automotive environments developed by Broadcom is the key element for a breakthrough of Ethernet in this environment. It enables OEMs and suppliers to implement Ethernet-based data bus systems without EMC problems and at very low cost in even safety-critical automotive environments, Matschi said. He added that in collaboration with Broadcom Continental has developed its own circuits to defuse the EMC problem on Ethernet UTP cables.

Matschi said the roll-out of Ethernet in cars can also be regarded as an element of the merger between the outside IT world and the hitherto isolated