The Automotive Physical Layer standard will support in-vehicle video transmission from 2 Gb/s to 48Gb/s and above.
By Murray Slovick, Contributing Editor
In-vehicle connectivity is evolving to keep up with the advances of technologies. However, with new sensors being deployed and an increasing amount of data flowing into and out of the car, multi-gigabit speeds are now required for modern vehicle designs.
In response, Valens announced that the MIPI Alliance has selected its technology as the foundation for the Alliance’s Automotive Physical Layer standard (A-PHY). This standard will be used by the automotive industry to provide high-speed links for cameras, displays, and sensors for autonomous applications.
The MIPI Alliance is a collaborative organization serving industries that develop mobile devices. The focus of the organization is to design and promote hardware and software interfaces that simplify the integration of components built into a device, from the antenna and modem to peripherals and the application processor.
MIPI’s A-PHY is a physical-layer specification targeted for advanced driver-assistance systems (ADAS), autonomous driving systems (ADS), and other surround sensor applications in automotive (e.g., for displays, cameras). While most MIPI specifications are designed for shorter reaches for use within mobile devices, A-PHY will be capable of reaching up to 15 meters in the demanding automotive environment.
A-PHY is being developed as an asymmetric data link in a point-to-point topology, with high-speed data, control data, and optional power sharing the same physical wiring. A-PHY will support two “profiles” in one specification, aiming to meet the industry’s need for lightweight wiring harnesses, low power consumption, low electromagnetic interference (EMI), and strong noise immunity.
A-PHY will support speeds of 16 to 24 Gb/s, with a roadmap to 48+ Gb/s and beyond (e.g., 100 Gb/s). This approach will ensure that A-PHY has the scalability to meet and stay ahead of the automotive industry’s burgeoning bandwidth requirements (see figure).
As an example, consider automated lane centering. This application requires several cameras and the processing of camera, radar, and LiDAR information. By providing a single interface, A-PHY aims to make development easier for engineers designing these types of ADS solutions.
More efficient cameras enable increased ADAS and ADS functionality, and in turn greater convenience and safety. But each additional camera also drives more interfaces and, hence, more data traffic. A-PHY is designed to be scalable so that systems designers can worry less about the data bottleneck.
Valens’ solution was determined best-suited to address the need for high-speed, in-vehicle video links and to support the range of bandwidth defined by MIPI’s automotive standard. MIPI outlined two main profiles for its A-PHY standard: Profile 1 to support lower speeds, and Profile 2 to support all speeds from 2 Gb/s up to 48 Gb/s and above.
Profile 2 will be based on a Valens’ PHY-level Retransmission Scheme (RTS). With RTS, if a data error is detected in the receiver, a retransmission request is sent back to the transmitter. The data packet is then resent using a lower PAM modulation with narrowband interference cancellation (NBIC).
The final specification is expected to be completed by the end of 2019. MIPI’s will be the first high-speed asymmetric standard in the market.
“This is a vote of confidence in Valens and our technology as we continue to pave the way towards connected and autonomous vehicles,” said Dror Jerushalmi, CEO and co-founder of Valens. “The company values the importance of developing automotive industry standards, guaranteeing the most resilient systems for the ultimate safety of the connected and autonomous vehicles, and we look forward to working with the MIPI Alliance to bring the A-PHY standard to reality.”
“As the market for connected and autonomous car grows, the need for more devices—cameras, displays, sensors—will exponentially increase, with expectations of 20+ chipsets in a mid-range car,” said Ian Riches, VP, Global Automotive Practice, Strategy Analytics, a business consulting and custom research firm based in Boston, Mass.