As automotive electronics evolve, adding more complex functions and features to the mix, the need for faster and more reliable data transfer is critical. In response to this evolution, recent amendments to IEEE Std 802.3-2022 Standard for Ethernet add Physical Layer (PHY) specifications and management parameters for faster data rates across both glass optical fiber and single balanced-pair copper conductors Ethernet in automotive environments.
For glass optical fiber, amendment IEEE 802.3cz™-2023 adds PHY specifications and management parameters for 2.5 Gb/s, 5 Gb/s, 10 Gb/s, 25 Gb/s, and 50 Gb/s data rates. Amendment IEEE 802.3cy™-2023 adds physical layer specifications and management parameters for 25 Gb/s data transfers on a single balanced pair of copper conductors.
The Need for Speed
Since the first days of computers, the quest for ever faster systems with lower latency has continued. The greatest demands came from the business, commercial, science/engineering, and military/aerospace sectors, as well as from hardcore gamers. Although faster, reliable operation is both desirable and critical to these sectors, the automotive market presents a plethora of requirements and challenges.
In many ways, automakers face some of the same issues as aircraft designers, with safety being priority number one and crew and customer comfort a close second. Along with safety, automakers are constantly trying to create unique features while meeting customer demands for greater reliability, low maintenance, comfort, entertainment features, better connectivity, etc., all of which require fast, reliable data transfers.
Automotive Ethernet, a cabled network connecting various parts of a vehicle, enables highly efficient data transfers in current connected automobiles, while holding great promise for future vehicle designs. There are strong indications that Ethernet will replace the traditional automotive CAN-bus and others in the near future.
Automotive Ethernet in a distributed vehicle network provides broad connectivity and the low latency and quality of service required for advanced control functions and full-motion video. It also lets the vehicle be lighter, more affordable, more efficient, and reduces power requirements.
As Automotive Ethernet will handle ever expanding safety, communication, and electronic features, both higher data rates and the ability to select the optimal data rate and cable medium for specific functions will be required. This is where IEEE 802.3cz-2023 and IEEE 802.3cy-2023 fit the bill.
Increasing demand for Advanced Driver Assistance Systems (ADAS) will increase the need for automotive Ethernet. Autonomous vehicles rely on high-definition (HD) maps created from sensor data that display road conditions such as lane numbers and sizes, crosswalks, road signs, etc. Ethernet connects these components, exhibits zero latency in ADAS, and provides fast and efficient data transfers to ensure the vehicle maneuvers safely.
Currently, in-vehicle and external cameras, HD displays, and Light Detection and Ranging (LiDAR) sensors operate at data rates beyond 1 Gbps. And, as these components evolve, those rates will continue to rise. These are critical safety components that require reliable cabled connections that can handle large data loads in as close to real time as possible. Again, Ethernet is the preferred connective technology.
A great advantage of copper-based Ethernet is its ability to provide electrical power along with data, a feature called Power over Data Lines (PoDL). Not to be confused with Power over Ethernet (PoE), which uses two twisted wire pairs, PoDL requires just one pair, thereby reducing architecture complexity. Additionally, PoDL can deliver up to 500 mA of current.
Fiber optic Ethernet provides the ability to operate over longer cables at high data rates.
The automotive environment poses a formidable challenge to any form of connectivity. High heat, extreme cold, nature’s elements, road debris, strong vibrations, grease, dirt, and internal fluid leakage threaten weak, porous cables and connectors. Ethernet cables and their connectors as the Ethernet communication logic will have to safely operate under these extreme conditions.
Naturally, the more robust these components are, the higher their cost. However, as demand for these components increase, volume will help automotive suppliers to design formidable components while controlling costs.
Automobiles are notorious for generating both mechanical and electrical noise, particularly electromagnetic interference (EMI). As auto manufacturers integrate more electronic features, particularly audio, video, and wireless technologies, the possibilities for noise generation will escalate.
Automotive Ethernet currently employs cables and connectors that minimize EMI. Twisted pair and fiber optic cabling are time-tested cabling that reduce EMI susceptibility.
To further minimize EMI effects, twisted pair automotive Ethernet connectors integrate a shield that surrounds both the cable and contacts. However, as integration escalates, more R&D on the part of Ethernet cable makers will be necessary to address the potential noise issues future innovations may induce.
In addition to fiber optic cable immunity to EMI, the new fiber optic Automotive Ethernet interfaces will provide longer cable lengths which provides additional vehicle application options
With greater connectivity forecasted for future vehicles, whether electric, hybrid, autonomous, or perhaps some highly unique variation, a classic challenge constantly threatening all things digital is cybersecurity.
In comparison to CAN connectivity, automotive Ethernet security is complex and will require diligence, research, and focused management. These vehicles will have a connection to the outside world by some sort of wireless network, making for a potentially large attack surface.
Essentially, effective cybersecurity solutions will require moment-to-moment attention, developing side-by-side with vehicle network design.
Automotive Ethernet will continue to face unique challenges, including harsh automotive environments and the ongoing battle against cyber threats. But these two new amendments to IEEE 802.3 go a long way to meeting these challenges for today and the near future.