Lightweight Gigabit Ethernet cables offered for car networking
The reduced twisted pair Ethernet cables would have fewer copper wires inside
By Stephen Lawson | Published: 10:05, 03 April 2012
Ethernet has gained speed many times, and now it may be about to lose weight.
On Monday, the Institute of Electrical and Electronics Engineers (IEEE) announced the formation of a study group on reduced twisted pair Gigabit Ethernet. The group will look at whether to develop a standard that would deliver performance as high as the current Gigabit Ethernet over cables with fewer wires inside, a goal considered important for in-car networks.
Ethernet is starting to emerge as a key automotive technology as cars are equipped with more entertainment and communication options, plus safety features such as rear-view video cameras. Though cellular and satellite communications are increasingly important to link a car to the world outside, and Bluetooth and Wi-Fi have roles inside, such as for hands-free phone use, some data transfers in a car still need to happen over wires.
Wireless networks are affected by too many performance variables, including interference, to be used for linking electronics in cars, according to Kevin Brown, vice president and general manager of chip maker Broadcom's Ethernet Transceiver Business Unit. High speed, low latency and reliability are critical for transmitting signals among different parts of the car, especially for safety-related functions, he said.
Broadcom already offers equipment for a thin cable version of 100Mbps Ethernet, which is supported by a group called the Open Alliance Special Interest Group that includes BMW, Hyundai, car component maker Bosch and other automakers and partners, Brown said. Cars with that technology will hit the market next year, he said. But as cars' electronic capabilities evolve, Gigabit Ethernet is likely to be needed within a few years, he added.
As future vehicles are designed, the number of possible electronic features is growing to include multiple outside cameras, more sophisticated control systems and better platforms for driver information, entertainment and navigation. Today, in-car networks typically use specialised, proprietary wiring for different connections around the car. It would be easier to incorporate new systems if cars had standard Ethernet networks that each component could plug into, according to Brown.
However, the need for fuel efficiency means that weight is a major consideration for any component of a car, so the new IEEE 802.3 Reduced Twisted Pair Gigabit Ethernet Study Group may try to define an alternative to the cable used for Ethernet in buildings. That cable has four pairs of copper wires, and the standards group thinks it might be possible to run Gigabit Ethernet on a cable with fewer pairs. This type of cable might have other uses, such as industrial control and avionics, the IEEE said in a press release.
The standards group is inviting individuals to contribute to the new study group, which is scheduled to meet at the IEEE 802.3 Ethernet Interim Session starting May 14 in Minneapolis.
The wires inside Ethernet cables are arranged in pairs to improve their immunity to signal noise, said Steve Carlson, chairperson of the Reduced Twisted Pair group. There are already cables for 10Mbps and 100Mbps Ethernet with two pairs of wires, but Gigabit Ethernet cables are only available with four pairs, he said.
The automotive industry has been clamouring for a Gigabit Ethernet cable with fewer pairs and is already expecting it to be developed, Carlson said. So although it may take three years to complete the standard and additional time to get new products approved for use in cars, there may be vehicles on sale by 2020 with the new technology, he said.
The cost of copper has risen by as much as three times in the past six years, so cables with fewer wires could save all Gigabit Ethernet users money, Carlson said. But whether the new standard will be compatible with conventional LANs will depend on how it's implemented. Automakers want the thinnest possible cable, but there are tradeoffs including compatibility with LANs, he said.
Auto maker Ford also voiced support for the standards effort.
"Ethernet has its natural advantages of scale, tacit interoperability, ubiquity, deep cross-industry adoption and hence a rich spectrum of applications and global availability of skills," said K. Venkatesh Prasad, leader of the Vehicle Design and Infotronics group at Ford Research and Innovation. "The standard will help drive adoption and drive down the cost of automotive acceptance testing."