A bit on the software-defined vehicle (SDVs)

In-vehicle systems have massively grown in complexity with more installed speakers, microphones, cameras, displays, and compute burden to process the necessary information and provide the proper, often time-sensitive output. The unfortunate side effect of this complexity is the massive increase in ECUs and subsequent cabling to and from its allocated subsystem (e.g., engine, powertrain, braking, etc.). The lack of practicality with this approach has become apparent where more OEMs are shifting away from these domain-based architectures and subsequently traditional automotive buses such as local interconnect network (LIN), controlled area network (CAN) for ECU communications, FlexRay for x-by-wire systems, and media oriented transport (MOST) for audio and video systems. SDVs rethink underlying vehicle architecture so that cars are broken into zones that will directly service the vehicle subsystems that surround it locally, cutting down wiring, latency, and weight. Another major benefit of this are over-the-air (OTA) updates using Wi-Fi or cellular to update cloud-connected cars, however bringing ethernet to the automotive edge comes with its complexities.

ADI’s approach to zonal architectures

This year at CES, EDN spoke with Yasmine King, VP of automotive cabin experience at Analog Devices (ADI). The company is closely working with the underlying connectivity solutions that allow vehicle manufacturers to shift from domain architectures to zonal with ethernet-to-edge (E2B) bus, automotive audio bus (A2B), and gigabit multimedia serial link (GMSL) technology. “Our focus this year is to show how we are adding intelligence at the edge and bringing the capabilities from bridging the analog of the real world into the digital world. That’s the vision of where automotive wants to get to, they want to be able to create experiences for their customers, whether it’s the driving experience, whether it’s the back seat passenger experience. How do you help create these immersive and safe experiences that are personalized to each occupant in the vehicle? In order to do that, there has to be a fundamental change of what the architecture of the car looks like,” said King. “So in order to do this in a way that is sustainable, for mobility to remain green, remain long battery range, good fuel efficiency, you have to find a way of transporting that data efficiently, and the E2B bus is one of those connectivity solutions where it’s it allows for body control, ambient lighting.”

E2B: Remote control protocol solution 10BASE-T1S solution

Based on the OPEN alliance 10BASE-T1S physical layer (PHY), the E2B bus aims at removing the need for MCUs centralizing the software to the high performance compute (HPC) or central compute (Figure 1). “The E2B bus is the only remote control protocol solution available on the market today for the 10BASE-T1S so it’s a very strong position for us. We just released our first product in June of this past year, and we see this as a very fundamental way to help the industry transform to zonal architecture. We’re working with the OPEN alliance to be part of that remote control definition.” These transceivers will integrate low complexity ethernet (LCE) hardware for remote operation and, naturally, can be used on the same bus as any other 10BASE-T1S-compliant product

BMW has already adopted the E2B bus for their ambient lighting system, King mentioned that there has already been further adoption by other OEMs but they were not public yet. “The E2B bus is one of those connectivity solutions where it allows for body control, ambient lighting. Honestly, there’s about 50 or 60 different applications inside the vehicle.” She mentioned how E2B is often used for ambient lighting today but there are many other potential applications such as driver monitoring systems (DMSs) that might detect a sleeping driver via the in-vehicle biometric capabilities to then respond with a series of measures to wake them up, E2B allows OEMs to apply these measures with an OTA update. Without E2B, you’d have to not only update the DMS, but you’d have to update the multiple nodes that are controlling the ambient light. The owner might have to take it back into the shop to apply the updates, it just takes longer and is more of a hassle. With E2B, it’s a single OTA update that is an easy, quick download to add safety features so it’s more realistic to get that safer, more immersive driver experience.” The goal for ADI is to move all the software from all edge nodes to the central location for updates.

Figure 1: EDN editor, Aalyia Shaukat (left) and VP of automotive cabin experience, Yasmine King (right) in front of a suspension control demo with 4 edge nodes sensing the location of the weighted ball, sends the information back to the HPC to send commands back to control the motors. 

A2B: Audio system based on 100BASE-T1

Based upon the 100BASE-T1 standard, the A2B audio follows a similar concept of connecting edge nodes with a specialization in sound limiting the installation of weighty shielded analog cables going to and from the many speakers and microphones in vehicles today for modern functions such as active noise cancellation (ANC) and road noise cancellation (RNC). “We have  RNC algorithms that are connected through A2B, and it’s a very low latency, highly deterministic bus. It allows you to get the inputs from, say, the wheel base, where you’re listening for the noise, to the brain of the central compute very quickly.” King mentioned how audio systems require extremely low latencies for an enhanced user experience, “your ears are very susceptible to any small latency or distortion.” The technology has more maturity than the newer E2B bus and has therefore seen more adoption, “A2B is a technology that is utilized across most OEMs, the top 25 OEMs are all using it and we’ve shipped millions of ICs.” ADI is working on a second iteration of the A2B bus that multiplies the data rate of the previous generation, this is likely due to the maturation of the 1000BASE-T1 standard for automotive applications that is meant to reach 1 Gbps. When asked about the data rate King responded, “I’m not sure exactly what we are publicly stating yet but it will be a multiplier.” 

GMSL: Single-wire SerDes display solution

GMSL is the in-vehicle serializer/deserializer (SerDes) video solution that shaves off the significant wiring typically required with camera and subsequent sensor infrastructure (Figure 2). “As you’re moving towards autonomous driving and you want to replace a human with intelligence inside the vehicle, you need additional sensing capabilities along with radar, LiDAR, and cameras to be that perception sensing network. It’s all very high bandwidth and it needs a solution that can be transmitted in a low-cost, lightweight cable.” Following a similar theme as the E2B and A2B audio buses, using a single cable to manage a cluster display or an in-vehicle infotainment (IVI) human-to-machine interface (HMI) minimizes the potential weight issues that could damage range/fuel efficiency. King finished by mentioning one overlooked benefit of lowering the weight of vehicle harnessing “The other piece that often gets missed is it’s very heavy during manufacturing, when you move over 100 pounds within the manufacturing facilities you need different safety protocols. This adds expense and safety concerns for the individuals who have to pick up the harness where now you have to get a machine over to pick up the harness because it’s too heavy.”

Figure 2: GMSL demo aggregating feeds from six cameras into a deserializer board going into a single MIPI port on the Jetson HPC-platform.

Aalyia Shaukat, associate editor at EDN, has worked in the design publishing industry for six years. She holds a Bachelor’s degree in electrical engineering from Rochester Institute of Technology, and has published works in major EE journals as well as trade publications.

Related Content

CES 2025: Moving toward software-defined vehicles
CES 2025’s sensor design highlights

The post ADI’s efforts for a wirelessly upgraded software-defined vehicle appeared first on EDN.