Is Ultrawideband still a viable wireless technology?

Toward faster, more useful wireless personal-area networks

Ultrawideband (UWB) has long been promoted as the future of wireless personal-area networks (WPAN). But are WPANs still needed?

To begin, PAN is perhaps a bit of a misnomer since personal-area connections traditionally have been mostly point-to-point using, primarily, serial and parallel connections. But with the advent of USB and Firewire (IEEE 1394) technologies, personal-area networks gain the potential for a network topology. Extending these with wireless seems natural and, indeed, the first wireless USB products are now appearing on the market.

The most widely used WPAN technology so far has, of course, been Bluetooth, although it's rare to encounter those who actually use Bluetooth for anything more complicated than connecting a headset to a cell phone handset. However, Bluetooth is, in fact, a rich set of applications that support lots of useful personal functions, from printing and faxing to connectivity for file synchronization. But for these applications, Bluetooth can seem redundant with Wi-Fi.

Bluetooth software on Wi-Fi would be terrific, I believe. Bluetooth on IP would be ideal. But, for now, Bluetooth has instead been ported to ultrawideband adapters, which are also the basis of wireless USB. We're talking here about, theoretically, amazing levels of wireless throughput on the order of the 480Mbit/sec. of USB 2.0. That 480Mbit/sec. represents a peak speed, so we'd expect to see throughput of 150-200Mbit/sec. on both wired and wireless USB. But there's always a caveat when we talk about wireless throughput, and that is the inverse relationship between distance and throughput, especially with indoor, low-power systems operating in the unlicensed bands.

Ultrawideband got its name because each UWB channel is on the order of 500 MHz. That's very wide compared to, say, the 5 MHz. of UMTS, the 10-20 MHz of WiMax, and the 20 Mhz of Wi-Fi. More bandwidth usually means more throughput. However, because UWB operates over such wide channels, and because these channels are also used by other services, UWB must operate at very low power in the range of millionths of a watt. This means that UWB might have terrific throughput, but performance will fade rapidly with distance. That's not a bad thing, though, since PANs are indeed personal and usually operate only over a distance of a few meters, tops. As a result, UWB could be quite useful in room-size applications.

But there are two problems here. First, 802.11n is gunning for this kind of throughput and can operate at much higher transmission power levels. If we can get this kind of throughput from Wi-Fi, the demand for UWB might be quite limited indeed, assuming roughly the same cost and price points for both. And could we implement both USB and Bluetooth over Wi-Fi? Of course.

The second problem, however, is more serious: Initial testing of UWB products is showing pathologically low throughput. I spoke with two engineers, both of whom have significant design and testing experience, who are evaluating UWB products. They mentioned that throughput of less than 20Mbit/sec. at a range of a meter or so is common, although up to 60Mbit/sec. has been measured. The exception to this is in reference-design products from Pulse-Link, which does not follow the certified Wireless USB spec. Here, throughput of over 500Mbit/sec. has been observed -- megabit Ethernet speeds on wireless.

So, why the limited performance of wireless USB? I debated this with the engineers doing the testing, and we discussed three possibilities. First, there could be a fundamental flaw in UWB or WUSB. This seems unlikely, since a lot of companies invested a lot of money in the technology and likely would not have done so without effective due diligence. Second, there could be flaws in today's hardware implementations, since first-generation chips are usually not all they could be. And finally, it could be a simple matter of immature firmware and drivers, a common problem. New drivers and firmware can often work wonders, as we saw in the case of upgrades of Draft 1 802.11n products to Draft 2.

And, as we saw with Draft 1 802.11n products, vendors often bring products to market before their time. I'm confident that the UWB community will achieve performance levels commensurate with those of wire, at least at short range. If not, 802.11n is going to play an even bigger role than it does today.

Craig J. Mathias is a principal with Farpoint Group, an advisory firm specializing in wireless networking and mobile computing. He can be reached at craig@farpointgroup.com.

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Craig J. Mathias

Computerworld
Show Comments

Cool Tech

Breitling Superocean Heritage Chronographe 44

Learn more >

SanDisk MicroSDXC™ for Nintendo® Switch™

Learn more >

Toys for Boys

Family Friendly

Panasonic 4K UHD Blu-Ray Player and Full HD Recorder with Netflix - UBT1GL-K

Learn more >

Stocking Stuffer

Razer DeathAdder Expert Ergonomic Gaming Mouse

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

Featured Content

Product Launch Showcase

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?