The future of MOST In-vehicle networking today and tomorrow

Since the foundation of the MOST Cooperation in 1998, 13 years have elapsed. More than 100 car models relying on the powerful infotainment backbone have been launched, and the third generation of Media Oriented Systems Transport and MOST150 is about to be launched for mass pro-duction. As always, even before one technology generation is close to its peak, the question arises: what comes next?

The future of infotainment networking can be divided into two categories. For the European luxury brands, which have driven the adoption of MOST from the very beginning, the future will surely look different than for the many followers focussing on the mass market. 

As of today, only 10 to 20 percent of all passenger vehicles are equipped with an infotainment network. At the same time, many car makers who have not previously been highly focused on infotainment systems are facing the need to improve in order to keep pace with the digital world, offering networked applications. For those car makers, it is very important to rely 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 MOST50 or MOST150 technology is a rock solid and straightforward approach, providing a well-understood network and taking advantage of the existing MOST specifications, components, software stacks, and development tools. The focus is on low-cost, low-risk, and a very short time to market. The available data rates are more than sufficient for the transmission of even multiple HD channels; the protocol stack, which has been developed and debugged for more than ten years, offers almost everything needed.

With the MOST50 UTP electrical physical layer, 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 OEMs, the requirements are different. In-vehicle infotainment is about to saturate the market in terms of new and useful functions and features. Connectivity outside the car is becoming much more important than pure entertainment. More and more IP-based applications will arise, making extensive use of the MOST Ethernet Packet channel (MEP), which is new and specific to MOST150. Here, any standard protocol stack can be used on top of MOST, providing both the advantages of a synchronous network and a powerful data pipe for IP/Ethernet data.

Just as 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, portable consumer devices attached via USB, and car-to-x applications connected via either WLAN or LTE. 

Driver assist network is required

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 ecosystem of the vehicle for driver assist applications.

However, as with all new technologies, one of the key questions is how to start. Besides all the technical discus- sions, 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 from and 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 that is not yet established in the automotive market will have to blaze its trail through low initial volumes and immaturity - MOST and FlexRay experienced exactly the same thing during 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 and specifications that 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.