The advent of what have become known as ‘connected cars’ has meant that vehicle occupants can access an abundance of information and media content, supplied in all manner of different forms. This has serious implications however, as bandwidth-heavy infotainment features are now placing greater demands on the associated data communication resources.
There are currently an expansive array of in-vehicle communication protocols that are being incorporated into automobile models. Many of them could, potentially, support this increasing demand for greater infotainment functionality. Among these are LIN and CAN - both of which are very well established, as they already provide the infrastructure needed for other functions (powertrain and safety related in the case of CAN, lighting and climate control related in the case of LIN). These have in recent times started to be complemented by emerging protocols, such as CAN-FD, FlexRAY and MOST. The suitability of these buses to address infotainment tasks is to some degree limited though. Each has certain characteristics that preclude them from being a fully optimised data transfer solution for this type of application. For some it will be the low speeds offered, for others it will be security or scalability issues that compromise their effectiveness.
Instead of relying on new protocols, the automobile industry is starting to look towards proven interconnection technology. Having gained universal acceptance in enterprise data communication and industrial control sectors, Ethernet seems to be the answer. Its high bandwidth plus inherent robustness make it highly appealing to automotive engineers.
Just one obstacle has to be overcome if widespread automotive uptake of Ethernet is to be achieved - that is the carrier sense multiple access with collision detection (CSMA/CD) aspect of Ethernet’s media access control mechanism. Though CSMA/CD more than adequately manages any contention that occurs between devices on the same bus in non-time-critical applications, if the Ethernet protocol is to attend to other requirements where latency cannot be tolerated, then steps must be taken to put a more deterministic arrangement in place.
Gigabit Ethernet audio-visual bridging (AVB) presents engineers with a stable, reliable platform on which high speed multimedia data transmission can be carried out without latency problems arising. The introduction of advanced semiconductor technology optimised for Ethernet AVB systems will accelerate the deployment of Ethernet technology within the automotive sphere.