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Mix Magazine

This installment of The Bitstream column appeared in the July 2005 issue of Mix Magazine.

The Bitstream

This column discusses UWB, Ultra–wide Band communications technology…

UltraWeirdBand

When I was in school, radio was a simple thing. You got your carrier and you got your signal that you “impressed” on the carrier. Life was good. As for bandwidth, SNR and other parameters, not so good…Then, along came UWB or Ultra–Wideband, which turns the whole modulated carrier thing on its head and promises to open up a new world of wireless data transmission.

Back in the day, there were mainly two basic types of radio transmisssion, AM and FM. AM or amplitude modulation imposes and varying amplitude envelope on a fixed frequency carrier. Prone to all sorts of degradation from natural and manmade noise sources, AM leaves a great deal to be desired, but it was simple and ushered in the golden age of mass communications. It also paved the way for those visions from afar, television, that, until now, employed simple analog amplitude modulation of the picture. The subsequent massive popularity of electronic media delivery in the consumer marketplace, even during the Great Depression, drove the professional audio industry to move forward as well.

Thirty years after Guglielmo Marconi created the first practical “wireless,” Edwin Armstrong overcame the many shortcomings of AM transmission by inventing the method and machinery of frequency modulation or FM. Frequency modulation maintains a constant amplitude carrier, instead continuously varying the frequency about a “center,” avoiding the noise susceptibility that AM is prone to.

For a moment, let’s go back to the time of Mr. Marconi…A groovy Dane by the name of Valdemar Poulsen was working on a magnetic recorder, the progenitor of the “modern,” open reel analog machine still in use today. Radio research diverted his attention and, in short order, he came up with continuous wave transmissions, that carrier I’ve been babbling about, Before Poulsen, radio transmitters were of the spark gap variety and were only good for transmitting morse code. Now, if you’ve even tuned an AM radio in your car, you’ve heard the not so soothing tones of your ignition system in between stations. That radio energy, created as the air ionizes and a spark leaps across the gap of both plug and mechanical distributor, is a shotgun of amplitudes and frequencies, very brief in duration but potent in its output. That same concept of amorphous, carrier–less radio, forms the basis for Ultra–Wideband.

Zoom ahead in time, from spark gaps to technology gaps…Some crazy researchers, looking for ways to improve wireless data transmission, think way out of the box and notice that the early pioneers of radio, with their spark gaps, were producing a scattershot of radiated energy over a huge swath of spectrum. With that broad spectrum comes the ability to encode a gargantuan data payload…“Humm, veeery interesting…” With enough research thrown at it in the past decade, mostly from our armed forces, Ultra–Wideband technology has moved from swords to plowshare where it performs a wide variety of tasks.

Without getting into specifics too intense to comprehend, UWB can encode data from a very low rate, using miniscule amounts of power, to a very high rate, using a surprisingly small amount of power relative to continuous wave modulation schemes. That versatility, which trades complexity and power consumption for throughput, makes UWB a great approach for all sorts of data schleping tasks. Want a wireless “light switch” that you stick to your wall, anywhere you please, that uses so little power, it scavenges, battery–free, what little it needs from the temperature differential between wall and room? Want a better WiFI–style wireless network, that penetrates solid object better than current WiFI, providing good coverage regardless of transceiver location and data rates 8 times higher that 802.11a? Want a handheld imager that can look through walls and visually locate structural and wiring issues in your studio without resorting to the sledgehammer? All this and more is part and parcel of the ultrawide variety of UWB craziness to come.

At the past two Intel Developer Forums, UWB has shown up, first as a 2U prototype and then in a productized version, incorporated into wireless USB — low power, moderate data rate, close range; all good. According to the MultiBand OFDM Alliance, a trade group that united all the UWB proponents onto one bandwagon, the “Wireless USB Promoter Group was formed at the Spring 2004 Intel Developer Forum and is comprised of seven industry leaders — Agere Systems, HP, Intel, Microsoft Corporation, NEC, Philips Semiconductors and Samsung Electronics. In addition, Alereon, Appairent Technologies, Staccato Communications, ST Microelectronics, Texas Instruments, and Wisair are Key Contributors. The group was chartered with defining the Wireless USB (WUSB) specification with a bandwidth of 480 Mbps and to maintain the same usage and architecture as wired USB with a high-speed host-to-device connection.” Higher power, high data rate wireless FireWire and IP networks will also benefit. Again, the the MultiBand OFDM Alliance enthuses, “The 1394 Trade Association understands the evolutionary industry progression to provide wireless connectivity, especially for high speed applications. As such, they established a Wireless Working Group to specify a wireless protocol adaptation layer (PAL). The Trade Association in May 2004, published a wireless PAL for 55Mbps, whereby the significant and most fundamental elements for enabling a wireless protocol bridge were defined. With the consent of the Board of Directors, both the 1394-TA Wireless Working Group and the 1394-TA Compliance and Interoperability Working Group are now engaged with the MultiBand OFDM Alliance and the WiMedia Alliance, to define a platform as well as a compliance & interoperability plan for Wireless 1394a, operating at 400Mbps.” Low power, low data rate, longer range; also all good.

I mentioned the wireless light switch above, which is the purview of ZigBee, a set of protocols for digital communication via ultralow–power radio transceivers and are designed to move small amounts of data over moderate distances with little energy expenditure. ZigBee transceivers are meant to be placed…and ignored, running for years at a stretch without servicing. In addition to making wireless control of all kinds less costly, this technology bodes well for remote instrumentation of most any moving object, from house–sized printing presses to marmots under study by biologists.

That’s all this month. Next month, I’ll delve into some practicality in the modern wireless networking space. For a great read about the history of trad radio and the men who shaped our current world of mass communications, you might check a copy of Tom Lewis’ Empire of the Air out from your local library, at the same time you’re checking out those CDs for adding to your iPod collection. If you’re short on time, get ahold of the Ken Burns version on DVD…see you next time!

Bio

OMas is Director of Marketing Communications for Sonic Studio, LLC and, in his copious free time, has been motoring to the poetic musings of Dan Neil and his The Road Less Traveled podcast on KCRW.org.