Insights into the Launch of MOST150 in the New Mercedes-Benz S-Class

October 03, 2014 // By Jan Bauer, Daimler AG
This article shows the use cases and realization of a modern automotive infotainment system and makes evident why Daimler has once again chosen MOST Technology for the new Mercedes-Benz S-Class. Today MOST is the de-facto standard for connecting infotainment systems in a car. Evolving from MOST25, with a bandwidth of 25 Mbit/s, the recent generation – MOST150 – provides 150 Mbit/s as well as many new features such as isochronous streaming and automotive-ready, freely configurable Ethernet according to IEEE 802.3.

Since the very beginning of the MOST Cooperation in 1998, Daimler has actively contributed and developed MOST Technology. This was characterized by an initial double technology leap consisting of

a) digital transmission (to improve sound quality) and

b) optical transmission (to overcome EMC issues).

By 2005, every new Mercedes-Benz car was equipped with MOST at a bit rate of 25 Mbit/s. During this time frame it became clear that new requirements and challenges would show up on the horizon, and Daimler, together with the MOST Cooperation, started towards the 3rd generation of MOST with 150 Mbit/s [1].

During the development of several innovations on the one hand, it became clear on the other hand that it is important to exploit the bandwidth of the existing Plastic Optic Fiber (POF), thus allowing for an easy migration path from MOST25 to MOST150.

1. Requirements of the Infotainment in the New S-Class

In the new S-Class infotainment system, many new features have been required. Fig. 1 gives an overview of the supported infotainment use cases:

  • 12.3” central display
  • HDD navigation system with 3D city models and live traffic
  • Entertainment for front passenger with split-view technology.
  • Rear seat entertainment with 2 x 10.2” displays and independent access to all entertainment sources of the car
  • Playback of A/V entertainment sources
  • Integration of cell phones and CE devices
  • SMS/E-Mail
  • Web browser for all passengers in the car
  • Wi-Fi Hotspot
  • Remote Control App
  • Mercedes-Benz Online Apps

Fig.1: Infotainment in the new S-Class

As already mentioned in 2011 [2], when Daimler announced the adoption of MOST150 in a series project, one of the challenges consisted of the totally changed bus access structure: Whereas in traditional infotainment systems the Head Unit solely provided the user interface for the driver and optionally the co-driver, the rear seat entertainment system (RSE) was no longer a stand-alone system but connected and integrated to the MOST bus.

The infotainment system architecture consists of

Design category: