News

Bluetooth SIG "can't wait for ultra-wide" - so it hacks WiFi instead

by Tony Smith | posted on 11 February 2008

The organisation behind Bluetooth will tomorrow go public on its plan to borrow bandwidth from WiFi, allowing the device-to-device wireless connection technology to offer faster data transfers when it needs to.

It's a stepping stone, of course, until Bluetooth is firmly fitted on top of ultrawideband (UWB) radios, but until then, the trick – which it began hinting at privately late last year - should provide it with a speed boost way beyond what it can deliver today.

How does that square with Bluetooth's low power consumption characteristics? Bluetooth will only leverage WiFi if it needs it, and if the technology is present in the host device. It already is, in plenty of laptops and, increasingly, mobile phones too.

If Bluetooth detects that an application wants to transmit a large quantity of data, it will be able to grab the 802.11 radio temporarily. Once the data's sent, Bluetooth lets go of WiFi and goes back to its usual state.

To make this work, the organisation behind the wireless technology, the Bluetooth Special Interest Group (SIG) has to separate the Bluetooth profiles and protocols from the radio technology they currently operate on. Conveniently, it's already doing that, to enable Bluetooth to operate on UWB. So it's just a matter of building a WiFi foundation that can slot in alongside UWB, Wibree - for ultra-low power devices - and other wireless transmission systems.

It's a cunning move for two reasons. First, it provides a stop-gap until the Bluetooth SIG can complete its work on UWB. WiFi hardware is in place now, UWB kit isn't, and may not be until long after the SIG completes its UWB code. Second, it takes Bluetooth into the same territory as Wireless USB – as a way of connecting peripherals without cables. Indeed, the Bluetooth SIG specifically talks about Bluetooth+802.11 in terms of classic USB applications, like copying music files between an MP3 player and a PC, or sending photos from a camera to a PC or printer.

It's not going to happen soon, however. The architecture that will allow Bluetooth connections to sit on top of a variety of radio technologies isn't expected to be published to SIG members until mid-2009, so Wireless USB has plenty of time to establish itself.

The Bluetooth SIG began hinting that it might make use of Wi-Fi back in November 2007. Earlier that year, it published Bluetooth 2.1, which adds support for device pairing using near-field communictions - allowing products to be linked just be touching them together.