60 Ghz home wireless technologies ready for 2014

the new-fangled radio connections operate in the unlicensed 60-gigahertz band, where bandwidth is abundant and capable of providing data rates that rival those of fibre-optics.

Already Wi-Fi connections working at frequencies in the 2.4-gigahertz or 5-gigahertz bands have begun to replace USB (universal serial bus) cables for connecting computers to printers, keyboards and mice where data rates are modest. But the new 60-gigahertz connections look like being more than a match for even the “SuperSpeed” version of USB 3.0.

The 60-gigahertz band resides in the EHF (extremely high frequency) part of the spectrum, which spans frequencies from 30 gigahertz to 300 gigahertz. Beyond these reside the far infra-red and visible-light regions of the electromagnetic spectrum.

Oxygen molecules in the atmosphere resonate at 60 gigahertz, absorbing energy from radio waves at this frequency and attenuating them severely. Rain also causes such signals to fade. Even the normal humidity of the atmosphere takes its toll on the distance these so-called millimetre waves can travel. (At 60 gigahertz, the wavelength is 5mm.) They are also blocked by foliage and walls, and antennas need to be within line-of-sight of one another.

But for some applications, such restrictions can be a definite advantage —as in device-to-device communication over distances of up to ten metres (33 feet) or so. Such radio waves are ideal for beaming high-definition video from a computer to a television set across a living room, or for connecting a tablet to a docking station a few centimetres away.

Portable devices fitted with 60-gigahertz radio chips can swap vast amounts of data almost instantly when brought within range of one another. Their antennas need be only a couple of millimetres in size—making them small enough to be embedded in the radio chip itself.

adaptive beamforming:
This technique uses an algorithm on the transmitter side to determine where the receiver is located. It then focuses the signal between the two devices into a pencil-thin beam.

Apart from allowing even faster data transmission over longer distances, pencil beams provide extremely secure connections. With conventional Wi-Fi, which broadcasts in all directions, eavesdroppers can be outside in the carpark. To intercept a pencil beam they have to be in the same room—in the beam’s actual path—to have any chance of success.

Two 60Ghz wireless technologies:
One, an industry-led initiative known as WirelessHD, has been around since 2008. The other, a standard backed by the Institute of Electrical and Electronics Engineers (IEEE) known as WiGig, published its specification in 2010. In IEEE terminology, WiGig is known as 802.11ad.

WirelessHD and WiGig do broadly the same thing. In their present incarnations, both are capable of transmitting data at around seven gigabits a second—ten times faster than the slickest form of Wi-Fi networking today—and have peak data rates of around 30 gigabits a second.


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