A proposed wireless specification that allows lights to “talk” to devices became a standard this week, plus another that is used as the technology underlying short-range communications.
According to a note sent out by Bob Heile, the chairman of the IEEE 802.15 Working Group on Wireless Personal Area Networks, the IEEE Standards Board approved two standards: IEEE 802.15.7-2011, which uses visible light as a communications medium; and IEEE 802.15.4-2011, a short-range communications protocol for “personal” networks.
Neither will likely have as much impact as, say, IEEE 802.11, the basis for the various flavors of Wi-Fi. But the technologies offer some interesting possibilities for communications.
Take, for example, 802.15.7-2011. IEEE reserves its official standard for paying members; however, the abstract offers some clues as to its capabilities – in short, that lights could flicker at frequencies that are imperceptible to the human eye, but that could be used to transfer data from the light to a compatible device.
“The standard is capable of delivering data rates sufficient to support audio and video multimedia services and also considers mobility of the visible link, compatibility with visible-light infrastructures, impairments due to noise and interference from sources like ambient light and a MAC layer that accommodates visible links,” an IEEE abstract states. “The standard will adhere to any applicable eye safety regulations.”
What does this mean? Basically, the IEEE 802.15.7-2011 defines both a hardware interface and a protocol for sending information over light in 380- to 780-nm wavelengths; that covers the wavelengths that a human eye can see, plus a bit more.
A 2010 report by EE Times notes that the standard was not designed to cause lights to flicker annoyingly, and was designed to allow lights to be dimmed and to still communicate. A graphic designed by Boston University also speculates that a car’s brake lights, connected to a 802.15.7-2011 chip, could be used to signal the car behind it to sharply brake in the case of an emergency – a function that existing “radar” solutions and the forthcoming DSRC technology could also perform.
White space technology
The scope of the second standard is somewhat unclear. The existing 802.15.4-2006 specification forms the foundation of wireless specs like ZigBee, but an amendment to it could also allow devices to be controlled en masse by radios transmitting in the “white space” range.
What’s unclear, however, is what the 802.15.4-2011 specification covers. One source, however, said that the 802.15.4-2011 specification appeared to concern “6Lowpan,” promoted by the Internet Engineering Task Force as a technology for short-range personal area networks.
The IEEE’s Heile was unable to be reached by press time.
In an email sent to the IEEE member list, however, the future amendment, also known as 802.15.4m, was described as a method for “large scale device command and control applications”.
In September 2010, the FCC opened the spectrum previously used by analog television signals, the so-called “white space”.
“The amendment enables operation in the available TV white space, supporting typical data rates in the 40 kbits per second to 2000 kbits per second range, to realize optimal and power efficient device command and control applications. It supports accepted methods of TV
White Space coexistence in existence at the time of development.”
The Project Authorization Request – the document that launches the standards process for 802.15.4m – is dated May 26. The expected date for submittal to the IEEE-SA for a sponsor ballot is July 2013.
For more from Mark, follow him on Twitter @MarkHachman.
For the top stories in tech, follow us on Twitter at @PCMag.