A2B and Ethernet in Automotive Applications: What, When, and How: Page 3 of 3

January 23, 2020 //By Matteo Crosio, Analog Devices
A2B and Ethernet in Automotive Applications: What, When, and How
The number of electronic systems in cars has increased in recent years, reaching higher levels of complexity with the adoption of new technologies for infotainment and advanced driver-assistance systems along with multiple sensors for many different purposes. This results in much higher amounts of data zooming across the vehicles. Carmakers and electronics developers therefore have to be aware of new networking technologies.

To summarize, IEEE 802.3bw plus TSN can be a suitable solution for deterministic communication within a car, replacing traditional buses. Moreover, 100-Base-T1 is evolving to a new 1000-Base-T1 standard that can reach 1 Gbps. However, such systems are complex, and these technologies are not mature enough for wide deployment within the automotive market.

Possible Scenarios

While the automotive market is starting to adopt A2B for audio transport in cars, Ethernet is still far from massive implementation when it comes to conveying data from different bus systems.

Applications like ANC, hands-free systems, noise generation for electric vehicles (EV), and emergency call (eCall) systems benefit from the simplification introduced by A2B technology. Moreover, in the future, it could be possible to bring the information from digital sensors directly to the A2B, simplifying the architecture of RNC systems.

However, A2B has a limitation in bandwidth related to the bus speed. Ethernet could reach the speed of 1 Gbps once the 1000-Base-T1 matures; with this bandwidth it could easily bring different kinds of data, from sensors to audio/video streams.

Autonomous driving is pushing for even further performances, heading to multigigabit network connectivity. So, which kind of scenario should we expect for the next few years?

A2B is an easy to implement technology, bringing power and data over the same UTP, with a deterministic support for fixed latency.

Ethernet, with the incumbent 100-Base-T1 (and 1000-Base-T1 in the future), will be a convergent technology allowing the aggregation of multiple data buses, but with an increased complexity for adding power (PoDL) and SW determinism (TSN).

Likely, a mixed solution based on A2B for audio transport and sensors, and a backbone implemented with a high speed Gb Ethernet for cameras, lidar, and radar, could fit most of the future mid-term needs of the automotive industry.

Figure 3. Basic PoDL architecture: data and power share the same differential channel.


Figure 4. Multidomain architecture

About the Author:

Matteo Crosio began his career at Analog Devices in 2011 as a field applications engineer based in Italy, after 10 years covering different technical roles in the semiconductor industry. With a mixed-signal background in aerospace and telecom applications, Matteo brings solid experience as a hardware and FPGA designer, with a special focus on time synchronization. As part of the European sales organization, he now supports the EMEA region on wired communication technologies. He can be reached at matteo.crosio@analog.com.

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