After years of being a technology to watch, the fast short range wireless technology called ultra-wideband has popped into reality. Two laptops from Dell and Lenovo have UWB built in, in the form of wireless USB.

When a wireless technology looks this good, it is tempting to expect it to replace the wired equivalent (the Burton Group has predicted Wi-Fi will replace Ethernet, for instance). However, most people agree that UWB won't replace wired USB any time soon - or, indeed, ever.

It's fast and standard

The speed is definitely there. Ultra-wideband technology (UWB) should carry data fast enough to send high-quality video, sound or images between devices up to 30 metres apart. It's been pitched as a potential cure for the cable clutter around PCs, TVs and handhelds, for several years.

UWB gets a very high data rate, starting at 480 Mbit/s, by sending information across a wide spectrum, from around 3GHz to 10GHz, including frequencies that other people - such as mobile operators and broadcasters - have licences to use. This doesn't cause a problem, however: because it uses such low power, it is indistinguishable from the legitimate noise leaked by other electronic equipment.

In the last year or so, UWB has been showing signs of changing from a potential to a real technology, passing several key milestones. IT gained EC approval for deployment in Europe, and the UK regulator Ofcom enacted this in the UK earlier this month. Before this, it was limited to the US and Japan.

More importantly, the regulators are working to make their UWB guildelines compatible, so there will be the kind of global market that will bring costs down. Most US-based devices currently use the lower part of the spectrum, partly because the silicon is cheaper, but as devices expand upwards, it will be easy to make equipment that can be used elsewhere: "Basically, you turn off bands other than the correct one for Europe. Since this is a software capability, it doesn't have additional cost," says Stephen Wood of Intel, who is president of the Wimedia industry group.

The technology has been selected as the basis for a wireless version of USB, and also for a faster version of Bluetooth. Both use Wimedia's UWB version, marking an end to the standards wars that marred UWB's earlier days, which at one point became so intense, the IEEE gave up on trying to standardise it.

"There will finally be a lot of UWB kit on the shelves of stores like Radio Shack in the US this Christmas," says Stuart Carlaw, wireless research director at ABI Research. It won't reach the UK till the middle of 2008, he warns. Real throughput will actually be around 250 Mbit/s, which is well beyond what we are expecting from Wi-Fi at that point.

But cables will continue

But the technology won't replace USB - or Bluetooth for that matter. Normal Bluetooth will continue to give better power usage, when lower speeds are needed (and there's even a lower speed Bluetooth called Wibree now).

Wired USB will also continue, because there are around two billion wired USB devices out there wanting to use it, and it has the potential to move on to even faster speeds: "The evolutionary path for a wired interface has significantly greater upward growth potential than anything wireless," says Wood, who is president of Wimedia. "A copper wire effectively has the use of the entire RF spectrum."

"Wireless USB (WUSB) will not likely replace wired USB in many instances, at least not in the near term," agrees Mark Bowles, vice president of marketing at UWB company, Staccato. "Wired USB is very inexpensive to deploy and it is likely that OEMs will continue to want the wired version even when wireless USB is added."

According to market researchers In-Stat, UWB won't sweep the board overnight, but will have an uptake that is very similar to the rate at which Bluetooth and Wi-Fi were adopted in PCs, going from 0.1 percent by the end of this year, to 4.1 percent by the end of 2011.

In mobiles, the price, size and power needs of UWB chips will be more critical than they are in the PC sector, but In-Stat expects it to penetrate further in phones than in PCs, just as Bluetooth has.

"Many new p2p applications are enabled with WUSB," says Bowles. "No one is going to carry a cable around to connect their phone to someone else’s." While there is no significant UWB presence in phones till 2009, it ramps up to 14 percent of the phones in the world, by 2011, according to In-Stat.

As ever, current technology has a lot to recommend it - the main benefits being the fact that it exists and is pervasive.