The first Ethernet applications for the automotive industry are On-Board Diagnostics (OBD) and the update of ECU flash memories. For the reading-out of diagnostics data and the updating of software within a given time frame, the performance of existing in-vehicle bus systems such as CAN and FlexRay was not sufficient. Ethernet 100Base-TX with CAT 5 has been chosen for the interface between the vehicle and the diagnostics test equipment. The higher bandwidth of Ethernet saves costs in service and production. ISO 13400 and ISO 14229 utilize existing industry standards and define a long-term stable state-of-the-art diagnostics standard. Products and components are already available from versatile suppliers as automotive requirements such as robustness and temperature tolerances have been relaxed for this specific use case.
2.2 Generation 2: Driver assistance systems and infotainment
The second generation of Automotive Ethernet will address infotainment and camera systems for surround view applications. Today’s rear-view camera solutions often use LVDS for the transfer of video data, which works well for single cameras. In future systems, this will consist of more cameras and fuse with sensor data from short/long-range radar, for example (Figure 3). An LVDS-based system becomes inefficient in terms of wiring harness and expensive cables and connectors. Switched Ethernet allows video cameras to be connected to a central control unit for synchronization and further processing.
Ethernet cameras can further benefit from “Energy-Efficient Ethernet” (IEEE 802.3az), which introduces a Low- Power Idle (LPI) mode and wake-up functionality to save energy when the cameras are not being used. Additionally, solutions for Power over Ethernet (PoE) are preferred to further reduce wiring harness. The demand for higher bandwidth and lower latency is obvious. Multiple high-resolution cameras for uses such as object detection require uncompressed data transfers, for example to avoid compression artefacts for obstacle detection, and are a strong driver of higher bandwidth.
Figure 3: Camera and radar for Driver Assistance Systems
Recent infotainment solutions are mainly based on proprietary and non-scalable technologies. Automotive Ethernet addresses this emerging application field in a cost-effective manner by making use of the AVB standard. Synchronized transmission of video and audio data with guaranteed latency can already be achieved with existing AVB Gen 1 Ethernet components. However, both applications fields will benefit from current AVnu standardization activities and the most recent Switch and PHY developments based on the BroadR-Reach physical layer.
While ethernet will support all of the functions that CAN, LIN and Flexray currently perform, I would dare say the costs at this stage would be prohibative for most major OEMs.
The old adage of "if it aint broke dont fix it" fits quite well, CAN and LIN a suitable for for their respective functions in an automotive application (such as door locking, window control etc), especially vs cost per unit, so why change .
Where ethernet will thrive is in the ADAS, infotainment and active safety, where the cost will be outweighed by the bandwidth and speed that ether can deliver. not to mention utilising POE (power over ethernet) to streamline harnessing to support small current devices such as cameras.
It was bound to happen. I've been involved in digital control system networks for the vast majority of my career. And I've seen any number of special purpose schemes giving way to IP/Ethernet, as Ethernet speeds have increased.
You can even see this in the commercial sector. For example, way back in the 1980s and early 1990s, starting with the telcos of Scandinavian countries, interest was mounting in migrating digital telephony from the strict circuit-oriented architectures, such as those in ISDN, the old DSn standards, SONET, and ATM, to packet-switched IP over Ethernet.
The automotive CAN bus is probably following this same trend.
Original objections are always about "predictability." However what invariably happens is, if the network speed is much higher than that of these criticial signals, then predicability can statistically be "guaranteed" anyway. And by the way, math works. The idea has merit.
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