Marvell jumps gun on Gigabit Ethernet for cars
The automotive industry has only begun to embrace the automotive Ethernet standard. The technology called “BroadR-Reach,” defined by OPEN Alliance industry group and designed to enable 100 Megabit per second data distribution inside the car, is getting designed into some cars. Meanwhile, the IEEE is turning the BroadR-Reach technology—originally developed by Broadcom—into a formal IEEE standard called 100BASE-T1.
Unlike Broadcom or NXP, though, Marvell isn’t a member of the OPEN Alliance, and the company is yet to launch commercial 100Mbps automotive Ethernet products.
Marvell’s pre-emptive move to push its gigabit Ethernet solution based on IEEE’s draft 1000BASE-T1 spec appears to suggest that the company is planning to leapfrog 100BASE-T1.
That, however, isn’t Marvell’s intention at all, stressed Alexander Tan, Marvell’s automotive solutions group product line manager. Rather, he said, “We see 100BASE-T1 and 1000BASE-T1 are complementary to each other. We want to offer to architects at carmakers and Tier Ones a full portfolio of automotive Ethernet solutions.”
The goal is to promote an automotive Ethernet that allows multiple in-vehicle systems to simultaneously access information over unshielded single twisted pair cable, he explained. Both IEEE standards—100BASE-T1 and 1000BASE-T1—use single-pair of wires, reducing weight and cost.
Marvell will demonstrate both single-pair automotive Ethernet solutions—one based on the draft 100BASE-T1 specification and another on the draft 1000BASE-T1—at a show called “the IEEE Standards Association (IEEE-SA) Ethernet & IP @ Automotive Technology Day 2015” in Japan later this month.
Kevin Mak, senior analyst at Strategy Analytics, described Marvell’s new gigabit Ethernet chip as “aiming to lower cost for gigabit-speed Ethernet, and, in turn, be an enabling technology for autonomous driving developments.”
He added, “Marvell will be first to market, but rivals will also be launching their devices in due course.”
Where inside a car will 1000BASE-T1 go?
Marvell sees a backplane of the vehicle network as one of the first places where 1000BASE-T1 will find its home.
Tan explained that a vehicle today consists of several separate domains, including Infotainment, Advanced Driver Assistance System (ADAS) and control domains. Each uses different dedicated interfaces and pre-defined connectivity technologies. “The missing link in connecting those different domains has been a low-latency, high-speed bus,” said Tan. The single-pair gigabit Ethernet based on the 1000BASE-T1 spec can fill the gap, he explained.
Another place where the use of 1000BASE-T1 chips makes sense is in connecting multiple cameras inside a vehicle.
Tan said vehicles today use two types of camera connectivity – one for vision applications and another for machine analysis.
Typically, carmakers accept compressed video for the vision apps, but not where computer vision analysis is required. That’s why, for the latter, LVDS (Low-voltage differential signaling) is still the preferred connectivity for transferring uncompressed video data.
Because uncompressed HD video needs more than 100 Megabit per second, even the 100BASE-T1 solution, at 100Mbps, requires video compression. The result is image degradation, and latency caused by the compression algorithm could add latency, said Marvell, limiting applications for Ethernet.
In contrast, at 1 Gigabit per second, “little or no compression is required.” The 1000BASE-T1 chips can support higher quality image transport for machine vision, HD console and instrument cluster. Marvell’s 88Q2112, based on 1000BASE-T1 spec, enables the transport of uncompressed 720p30 camera video, and supports multiple [compressed] HD video streams with up to 4K resolution, said Tan.
Unlike LVDS that is a point-to-point serial connectivity, the automotive Gigabit Ethernet implemented in a module can handle multiple video streams from the growing number of cameras inside cars, Tan explained.
Marvell’s 88Q2112 chip, further, features “upgrade compatibility to support both 100Mbps and 1000Mbps single-pair Ethernet solutions, and can be used to aggregate multiple 100Mbps Ethernet domains.”
The third obvious spot to use the Gigabit Ethernet chip is the infotainment space, according to Tan. This is where MOST (Media Oriented Systems Transport) has dominated inside a car as a dedicated high-speed multimedia network technology. The MOST bus, based on a ring topology, uses synchronous data communication to transport audio, video and voice signals.
With Gigabit Ethernet, “We can now support many more streams [than MOST] at a higher data rate in higher resolution,” said Tan.
Gigabit Ethernet solutions also offer automotive architects more flexible design options, said Tan. For example, they can move the place to show navigation information from the front display (seen in cars sold in North America) to rear seat (preferred in China), or any other places with high-resolution video display.
Ethernet simplifies car architecture
Because Ethernet enables “IP-based video that can be routed throughout the network,” its switched architecture can support “multiple configurations of modules” inside a car.
In short, Ethernet simplifies architecture, said Tan, allowing architects to use just one Ethernet connectivity switch, thus replacing proprietary SoCs currently used for every device handling video coming in and going out.
These are just three scenarios Marvell believes will drive initial tractions for its Gigabit Ethernet solution. Tan added that there will be many other new applications, he said.
One such example is autonomous vehicles. Take a look at a roof-top navigation unit installed on an autonomous car, said Tan. Google, for instance, used $80,000 Lidars with its early designs. “That [roof-top] unit costs as much as a vehicle,” Tan said. Self-driving cars remain still expensive because each sensory subsystem – such as laser, lidar, ultrasound and vision – has its own computer system to analyze the data. The Holy Grail of autonomous cars is to design at a reasonable cost by developing a centralized autonomous system, said Tan. Gigabit Ethernet will play a critical role, he noted, for body electronics domain aggregation, next-generation ADAS and autonomous cars.
Marvell is sampling its 88Q2112, based on the draft IEEE 1000BASE-T1 spec, early November to car OEMs and Tier Ones. Marvell’s goal is to “let architects see the performance of gigabit Ethernet so that they can start taking it very seriously now,” said Tan.
Asked when the IEEE will finish the standardization of 1000BASE-T1 spec, Tan hesitated to specify the timeline. However, once the standard is complete, it will still take as much as a year for the commercial chip to reach the market, said Tan, due to extensive qualifications.
Strategy Analytics’ Mak said that the gigabit Ethernet will first target high model segments and luxury branded OEMs. “But as the device would allow flexible implementation of Ethernet, there may also be the future possibility of an AVB backbone for mass market OEMs,” he added.
— Junko Yoshida is Chief International Correspondent, EE Times
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