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Broadcom Tackles 5 Questions on Ethernet in Cars

MADISON, Wis. — Right now, not many people in the know are willing to bet against the future that includes Ethernet in cars. Yet, angst and confusion continues to swirl around “automotive Ethernet” – whether this refers to the upcoming IEEE 802.3bw standard (also known as 100BASE-T1), the Broadcom-pioneered “BroadR-Reach” spec defined by the OPEN Alliance industry group, or any other variant.

Frequently asked questions about automotive Ethernet include its specific applications inside a car and whether it has enough bandwidth to meet ADAS requirements. There’s also concern about  Broadcom’s intellectual property, and most important, which car OEMs — other than BMW — are already using Ethernet.

As follow-up to a story EE Times posted last week, we sat down with Timothy Lau, director of automotive at Broadcom.

Beyond BMW
EE Times:   Besides BMW, who else in the auto industry is on board with the use of Ethernet in their cars?

Timothy Lau: Based on our direct engagement with automotive OEMs and Tier One’s, we see multiple OEMs developing Ethernet network solutions based on BroadR-Reach technology. Beyond the 2014 and 2015 BMW X5, those that are public now include the 2015 Jaguar Land Rover XJ and the 2015 Volkswagen Passat.

EE Times: For what specific applications are they using Ethernet in their models?

Lau: BMW has begun using automotive Ethernet to connect cameras to the optional surround-view system electronic control unit in the BMW X5. The Jaguar Land Rover is using automotive Ethernet in its infotainment network. The Volkswagen Passat is using Ethernet for a parking assistant. The Passat is a good example that illustrates BroadR-Reach is now rapidly moving into mass-market cars.

EE Times: What’s prompting a car maker to use BroadR-Reach for parking assist?

Lau: For parking assist, cost is the driving force. For example, car makers are adding several surround-view cameras in addition to a soon-to-be mandated backup camera. Previously, they used analog cameras, connecting them via LVDS [low-voltage differential signaling] over coaxial cables. Now as they transition from analog to digital cameras, BroadR-Reach turns out to be a less costly solution. BroadR-reach lets multiple in-vehicle systems simultaneously access information over unshielded single twisted pair cable.

EE Times: I’ve always thought the infotainment network inside a car would be the first place where BroadR-Reach would move in. But aside from Land Rover, we haven't seen many examples yet. Is that because MOST is too well established a bus in the in-vehicle infotainment network, and automakers are less inclined to replace it?

Lau: Our sense is that automotive OEMs will start embracing automotive Ethernet as more stuff – like heads-up displays, digital amplifiers, rear-seat entertainment, information clusters, etc. – begin hanging off the infotainment network. MOST will eventually run out of network bandwidth, because it's based on a ring network. Its network architecture forces newly added clusters to share bandwidth. In contrast, Ethernet is based on a switched network — not a shared network like MOST – so that it can adapt to adding more complex, higher performance systems to the network.

EE Times: I hear often ADAS is what’s fueling carmakers to embrace Ethernet. But take an example of the number of cameras installed at the front end of a vehicle. They’re there to detect objects running in front of a vehicle, and to determine what they are. My understanding is that automotive OEMs wouldn’t like you to compress that video. If that’s the case, the 100Mbits offered by Ethernet is not going to help ADAS.

Lau: That’s a good question. We see there are two types of ADAS –passive and active. Ethernet is perfect for passive ADAS, which includes applications like parking assist. But for active ADAS, you’re correct, car OEMs want video to be lossless so that images captured can be sent uncompressed to an image cognition block, in which its algorithm determines what it is.

IEEE standard's coming
EE Times: So, as I understand it, IEEE is putting together an automotive Ethernet standard, 802.3bw (also known as 100BASE-T1), slated to come out at the end of this year. Assume I’m a chip vendor. Shouldn’t I wait for the IEEE standard to get completed, rather than jumping the gun to become a member of OpenAlliance (which promotes BroadR-Reach)?

To read the rest of this article, visit EBN sister site EE Times.

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