In-vehicle networking today and tomorrow

Since the foundation of the MOST Cooperation in 1998, more than 100 car models have been launched relying on this infotainment backbone, and the third generation of Media Oriented Systems Transport (MOST) - MOST150 - is about to be launched for mass production. Like always, even before one technology generation is close to its peak, the question arises: What comes next?

In-vehicle infotainment
The future of infotainment networking can be divided into two categories. For the European luxury brands, who have driven the adoption of the MOST standard from the very beginning, the future will for sure look different than for the many followers who are more focused on the mass market than on the high-end premium segment.

As of today, only between 10 and 20 percent of all passenger vehicles are equipped with an infotainment network. At the same time, many car makers who have not been highly focused on infotainment to date, are facing the need to shape up in order to keep pace with the digital world, offering networked applications. For those car makers, it is very important to bet on a technology which is proven and shipping in high volume, offering state-of-the art performance and low price at a minimum risk.

The re-use of the MOST50 or MOST150 technology is a rock solid and very straight forward approach, providing a well understood network and taking advantage of the existing MOST specifications, components, software stacks and development and debug tools. The focus is on low cost, low risk and a very fast time to market. The available data rates are more than sufficient for the transmission of even multiple High-Definition channels and the protocol stack which has been developed and debugged for more than 10 years offers almost everything needed.

With the MOST50 UTP electrical physical layer, which has been in production since 2007, even a point-to-point link between a head unit and a DSP audio amplifier can be cheaper than an analogue connection plus a digital control bus.

Looking at the premium car makers, the requirements are a little different. In-vehicle infotainment is about to saturate in terms of new and useful functions and features. Connectivity outside the car (e.g. through LTE or Car-to-X communication) is becoming much more important than pure in vehicle infotainment networking. More and more IP based applications will arise, making extensive use of the Most Ethernet Packet channel (MEP), which is relatively new and specific to MOST150. Here, any standard protocol stacks can be used on top of MOST, providing both the advantages of a synchronous network and a powerful data pipe for IP/Ethernet data.

Equally important is an appropriate High Speed Interface connecting the network to equally high speed processing devices, making use of the full network bandwidth without loss.

Bandwidth requirements will be driven by fast software updating and fast media access to on-board mass storage devices (HDD/SSD), portable consumer devices attached via USB, and car-to-x applications, connected via either WLAN or LTE.

Driver assist
The need for a Driver Assist network is a hot topic in the industry and there is the fundamental agreement by many OEMs and Tier 1 suppliers that there will be a new cluster in the Electric/Electronic Eco System of the vehicle for Driver Assist applications.

However, as with all new technologies, one of the key questions is how to make a start. Besides all technical discussions, the economic implications will play a major role in decision-making. Using MOST150 for Driver Assist networking has the clear advantage that from the very beginning, future applications can benefit and take share in the volume generated by the infotainment market.

From 2013 onwards, MOST150 based Driver Assist networks can have a 'jump start' in terms of volume. In contrast, any other technology, which is not yet established in the automotive market, will have to blaze its trail through low initial volumes, immaturity in the vehicle and so on, like MOST and FlexRay experienced in their infancy.

It has been shown that by adding an appropriate safety layer, MOST can be enabled to address Functional Safety requirements up to ASIL D, while at the same time being able to re-use a major part of the technology, specifications (in particular car specific robustness and diagnostic features) which have been developed and debugged over the last 13 years. Over the longer term, uncompressed video transmission requirements may drive the bandwidth requirements of a Driver Assist network, too.