In the classic 1980s “Back to the Future” movie trilogy, Doc Brown – inventor of the DeLorean time machine – declares that "your future is whatever you make it, so make it a good one.” At Marvell, engineers are doing just that by accelerating automotive Ethernet capabilities: Earlier this week, Marvell announced the latest addition to its automotive products portfolio – the 88Q4346 802.3ch-based multi-gig automotive Ethernet PHY.
This technology addresses three emerging automotive trends requiring multi-gig Ethernet speeds, including:
1. Increasing integration of high-resolution cameras and sensors
The main applications for a high-speed network in a car are cameras and displays with uncompressed video streams. Cameras are now upgrading from resolutions of 720p to 1080p, moving to 4K and even 8K within a few years. In addition, the pixel size (color depth) has increased to 16 and 24 bits per pixel, with the refresh rate moving to 60 frames per second. The result? The bandwidth needed to carry the high-resolution video will need to grow correspondingly. While 1Gbps used to be sufficient, there are now many use cases that require data rates up to 10Gbps and beyond (see Figure 1). Figure 1
Infotainment and high-resolution displays are also driving the need for high-speed video over the in-vehicle backbone. At last year’s CES in Las Vegas (remember those big trade shows, before Covid?) the Byton M-Byte's jumbo, 48-inch interior screen grabbed headlines. But the revolution in car displays is really just starting. Dashboard displays with integrating touchscreen, controls and ambient lighting in complex 3D forms will be common features in future cars. Holograms and Changeable Surface Textures are new technologies that automotive designers are integrating into display screens.
Technologies such as Apple CarPlay and Android Auto, as well as Google-based infotainment suites, effectively transform these displays into extensions of our smartphones and smart homes, including support for video-conferencing that combines high-res displays and cameras.
Similarly, side mirrors – while still useful – are seeing their roles supplanted as well, as cameras integrating images of surrounding traffic now cover a much greater field of view. Soon, augmented reality technologies, based on high-resolution OLED displays and fish-eye cameras, will also help warn us of potential trouble. Some OEMs are now planning up to 12 screens – a virtual megaplex inside the vehicle.
The upshot? The in-vehicle network (IVN) will need to support unprecedented bandwidth.
In addition to the cameras and displays, the car sensors, like radar and lidar, also rely on higher data speeds. Today, existing high-bandwidth sensor modules integrate a pre-processing IC for initial data analysis and object detection. The processed data is transmitted to the SoC/GPU over low-speed interfaces like CAN (up to 10Mbps) or 100M Ethernet links.
However, with the latest generations of high-compute power SoCs/GPUs handling the growing sensor data, the new trend is to eliminate completely the pre-processing units in the sensor module (see Figure 2). This shift will help to reduce:
To support this trend, these sensors are already upgrading from 100Mbps to 1Gbps Ethernet links, and within a few years are expected to require multi-gigabit rates.
2. Growing Utilization of Powerful 5G Networks
While the COVID-19 pandemic and resulting quarantine dramatically reduced the time Americans spent commuting by car, as well as the number of cars sold, a new generation of vehicles promises to transform the automotive landscape in coming years. Not just more efficient electric vehicles, but more autonomous, connected vehicles empowered by the rollout of powerful 5G networks.
What are the advantages of 5G over current networks (like 4G)? To start with, 5G is fast. Real fast. From a peak speed perspective, 5G is 100x faster than 4G. This means almost instantaneous downloading of HD maps, movies, or over-the-air (OTA) applications and software updates.
Latency in 5G networks is also extremely low, enabling direct communication between of vehicles to everything (V2X) – vehicles, pedestrian, infrastructure, and cloud (Figure 3). Until now, vehicles had to communicate via a distant server. With 5G, vehicles can communicate directly with each other, exchanging key information about accidents, road conditions and other alerts. This 5G network is critical to autonomous transportation, which is designed to be safer, more efficient, and more sustainable. It will also offer passengers a rich experience in the car and better ways to use their time while on the road. This includes using interactive applications, watching movies, playing games or preparing for meetings as easily as they do at home. Figure 3
To support 5G’s high speeds and low latency, automotive 5G modems and backbone networks within the vehicle will need to support speeds of 10Gbps and higher – speeds that Marvell’s multi-gig Ethernet PHY already enables. In addition, this technology enables OEM’s to leverage Ethernet’s high quality-of-service features to meet the demands of emerging vehicle-to-vehicle communication and related infrastructure.
3. The Rise of Zonal Architecture
In many vehicles, the wiring that connects the electronic and electric components is so complex and extensive that, were it laid end to end, all those cables would stretch over a mile. This cable spaghetti is also very heavy. Obviously, complexity and weight both add significant costs, first in terms of labor, as well as energy consumption while driving.
Despite these drawbacks, such spaghetti is still the norm rather than the exception. That’s because many of today’s new vehicles are still built around the concept of Domain Architecture, where extensive cable harnesses connect independent domains such as Body, Telematics, ADAS, Infotainment and Powertrain directly to components that are spread all over the car. Figure 4 offers a simplified diagram of a typical harness system. Figure 4
Shedding the constraints of traditional wired harnesses, the most advanced vehicle designers are shifting toward Zonal Architecture, which leverages Ethernet as the backbone protocol between the car’s different zones. To support this concept, each zone of the car includes a Zonal Gateway – a switch that utilizes Ethernet to convert and aggregate the different domains and protocols, while preserving each protocol’s desired performance and quality of service (QoS). As Figure 5 illustrates, Zonal Architecture dramatically streamlines automotive wiring requirements, reducing cable, labor and energy costs. Figure 5
The shift to Zonal Architecture becomes even more powerful when augmented with in-vehicle centralized computing and storage – an approach that is just emerging in the automotive industry. With a backbone that can leverage the speed and the benefits of Ethernet (switching, QoS, security, virtualization) and the growing computing power of the latest CPUs, many OEMs are now gravitating toward a central processing architecture (see Figure 6). Figure 6 – Zonal architecture with Central Processing
Along with the central processing comes the need for central storage, to store the most relevant data in a way that is secure, fast, easy and reliable to access.
To be able to aggregate the high bandwidth data of each zone over the zonal architecture, the Ethernet backbone needs to support data speeds of 10Gbps and higher.
Marvell track record with Multi-gig Ethernet
Marvell was the first company to introduce 10G Automotive Ethernet PHY (AQV107), in 2018, which supported 2.5G, 5G and 10Gbps speeds over automotive cables. Next, Marvell supported the development of a new IEEE standard for Multi-gigabit Ethernet Automotive PHY (IEEE’s 802.3ch), and is now sampling to customers the 88Q4346, IEEE compliant 10GBASE-T1 PHY.
In addition, the new line of automotive Ethernet switches that Marvell introduced in 2020 included multi-gigabit ports. The 88Q5072 is a highly integrated 11-port managed secured switch that support 2.5Gbps and 5Gbps ports, and the 88Q6113 supports two ports of 10Gbps.
What’s next? In 2019 Marvell initiated a call-for-interest (CFI) in IEEE for a new standard for Automotive Ethernet PHY at rates “beyond 10G”. As a result, a new IEEE group (802.3cy) is currently developing a standard for 25G, 50G and 100Gbps automotive PHY.
In summary, the decade ahead will be transformative for the automobile industry, as OEMs leverage remarkable innovations in Ethernet to integrate more high-resolution cameras and sensors, tap the power of 5G networks, and implement Zonal Architecture. And with Marvell’s help, the future may arrive faster than anyone, even Doc Brown, ever expected.