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EETE MAY 2015

MOST: a gigabit data backbone for future car generations? By Christoph Hammerschmidt At the yearly MOST Forum, the number of attendees is constantly dropping. Is this an indicator that the MOST technology succumbs to the attack of Ethernet AVB? At the recent event in Esslingen, Germany, the MOST scene proved to be quite lively. Since last year’s MOST Forum several carmakers announced new models with MOST technology inside. Among them are Volvos latest top-end SUV XC90, BMWs 2 Series Active Tourer and the Audi TT. Actually, in the latter one, A MOST INIC (Intelligent Network Interface Controller) is used in a somewhat unusual and innovative way: It is part of Audis Virtual Cockpit System and thus in a domain that is not associated unambiguously to the infotainment probably as an industrys first. Meanwhile, in some 180 vehicle models worldwide, MOST is the underlying networking technology for the infotainment. While MOST networks are found mostly in upmarket and luxury sedans and SUVs from carmakers like Audi, Bentley, BMW, Daimler, and Rolls Royce, the technology has also arrived in the segment of the more affordable vehicles. An example is the Smart Forfour as the first subcompact vehicle with MOSTbased infotainment. At the MOST Forum, it appeared that the MOST technology has found its niche where it will be difficult to attack by its fiercest competitor, Ethernet AVB. Certainly, Ethernet has a place in the world: where smaller amounts of data with uncritical real-time behaviour need to be processed, packet-oriented technologies like Ethernet have their advantages, said Henry Muyshondt, Administrator of the MOSTCO, the group of companies that have gathered to develop and support the MOST technology. However, when it comes to transporting large amounts of streaming data for audio, video and camera signals, MOST will continue to be a superior solution. At the event, techniques to test and evaluate MOST-based systems took centre stage. Also software options to integrate MOST systems into Autosar environments were detailed by experts from Bosch subsidiary ETAS as well as from MOSTCO. But into which direction will the MOST technology develop in the future? Where are the priorities? Will the MOSTCO put the focus on additional functionality to turn it into a networking MOST forum What Audi did not bother to mention: The Virtual Cockpit (electronics assembly shown) of its TT roadster is connected to the infotainment section through a MOST link. platform that can be deployed in application fields beyond infotainment? Or will the ever-increasing bandwidth requirements of future applications (camera signal processing for automated driving functions, for example) set the pace for the developers? “In the short to medium term, users should expect more features and functions” Muyshondt said, “In the current market situation, this is more important than additional bandwidth”. The MOST group rainmaker added that in its current version, the MOST technology also supports multiple concurrent data streams and offers a full-fledged Ethernet channel. It also has a coax physical layer that does away with the cost disadvantages of optical data transmission. Nevertheless, in the more distant future, the bandwidth demand will return and enforce new developments, Muyshondt acknowledged. Though MOST50 (with a bandwidth of just 50 Mbps) is still our bestseller, new applications such as uncompressed camera signals and ultra-high definition video might require data paths in the Gigabit range, he said. Under this perspective it was no coincidence that some presentations dealt with ways to push the bandwidth limits of future MOST generations. Conrad Zerna from Fraunhofer Institute for Integrated Circuits (Fraunhofer IIS) showcased a prototype version of a 10 Gbps Physical Layer for Single Twisted Pair cabling (and thus the same cost-effective type of wiring as promoted by the Ethernet AVnu Alliance). The goal of the developers is transmitting this this amount of data across a distance of 10 m at a latency of less than 10 microseconds and a power consumption of less than 1 W in the TX/RX combination. Applications could be in-car data backbones or automotive MIMO arrays. At present, the team has devised a bandwidth of 7.9 across a distance of 14 m Gbps; Zerna hopes that through further optimisations it will reach the goal of 10 Gbps by end of May. Another presentation went far beyond the 10 Gbps solution from Fraunhofer, albeit it was just a mere research project, far from commercialisation. Researchers from the KU Leuven (Belgium) showed an alternative technology to copper and optical 12 Electronic Engineering Times Europe May 2015 www.electronics-eetimes.com


EETE MAY 2015
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