IP architecture of a MOST150 based infotainment system

October 12, 2012 // By Alexander Leonhardi, Uwe Walter, Rico Hauke, Marco Maniscalco
Internet access has become an essential feature of modern vehicle infotainment systems. Today, it is the prerequisite to provide the user with up-to-date online information and services. In the case of a high-end distributed infotainment system - which consists of, for example, a head unit (HU), a rear-seat entertainment unit and a TV tuner - the communication is largely based on the Internet Protocol (IP), whose mechanisms have to be coordinated accordingly.

This article presents the definition of the functionality and the roles of the different devices, the specification of possible connections and access rights, as well as the definition of IP-related settings for the system's IP architecture. The MOST Ethernet Channel introduced in MOST150 (see [1]) provides the necessary infrastructure to implement all necessary protocols and mechanisms (e.g., the Internet Protocol, IP, the Transmission Control Protocol, TCP, or the Hypertext Transfer Protocol, HTTP; for a definition of protocols used on the Internet see [2]) in a distributed infotainment system, while maintaining other essential communication features, e.g., the synchronous and isochronous channels for easy and efficient audio and video streaming.

In this article, we will discuss the elements of the IP architecture for the next generation of Daimler’s infotainment systems (for an overview of the system see [3]). We will describe the different basic features supported by the system’s IP architecture in the next section and the corresponding protocols, functionalities, and roles that are necessary for their implementation in Section 3. With the MOST Ethernet Channel, the underlying MOST150 network provides an efficient and easy to use solution for transmitting IP traffic. In Section 4 we will present the current status of the implementation and the results of performance tests with the respective protocol stacks, as well as open issues and optimizations. We will conclude the paper with an outlook on future work in Section 5.

2. Functionality Provided by the IP Architecture

In this section we will outline the basic functionality of the IP architecture.

First, different ways for realizing Internet access are supported: Internet access can be achieved via the user’s mobile phone connected to the HU, which acts as the central router, using Bluetooth or USB. As an alternative, a special country-specific or optional communication unit can be used. Such a communication unit can also be used to access certain vehicle-centric services like remote diagnostics functionality.

The Internet connection

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