Spark Gaps and Ultra Wide Band Data Transmission

Embedded Geek writes: "It sounds like the revenge of Marconi, but Scientific American has a story about the use of spark gap technology for Ultra Wide Band (UWB) data transmission to send data at 100 to 500 Mbps across short distances (five to ten meters). As with every new technology, 'engineers expect these UWB units to be cheaper, smaller and less power-hungry than today's narrowband radio devices,' but there might be some truth to the hype. The secret appears to be the lack of a carrier wave, allowing use of wide swaths of the spectrum for transmission (the few comments I read at the FCC site referenced in the article addressed spectrum allocation)." Read below for a few more links, too.

"The article pitches the technology as a challenger or succesor to Bluetooth and 802.11a. There are several commercial companies investigating the technology (Aetherwire, Multispectral, and others are cited in the article) and Intel has a paper cited in the article. Spin off applications from the components needed to make this technology work might include a GPS style system accurate to one meter and a radar technology that would allow seeing through walls for construction, rescue, and (ahem) law enforcement."

Comments

Because of the short pulses

[BiggestPOS]

These are supposed to look like noise to anything else transmitting. Since they spread the signal around a LOT of specturm, they are generally just raising the level of background noise.... What happens when enough of these devices get out there, and the noise floor rises to equal Everest?

IANA Explosives Expert but...

[Anonymous Coward]

"...For example, rather than picking up recorded movies at the video store, we may end up downloading films using a portable mass-storage unit and UWB wireless transmission while filling the car up at the fuel pump..." The whole spark gap transmiter + gasoline fumes seems bad for some reason.

MY ERROR 1/3000 of a cell phone Hair Dryer

[JohnDenver]

1/3000 of a cell phone.

Ultrawideband communications systems would share the same problem except that they deliberately operate at power levels so low that they emit less average radio energy than hair dryers, electric drills, laptop computers and other common appliances that radiate electromagnetic energy as a by-product. This low-power output means that UWB's range is sharply restricted--to distances of 100 meters or less and usually as little as 10 meters. For well-chosen modulation schemes, interference from UWB transmitters is generally benign because the energy levels of the pulses are simply too low to cause problems.

A typical 200-microwatt UWB transmitter, for example, radiates only one three-thousandth of the average energy emitted by a conventional 600-milliwatt cell phone.

No a magic technology.

[3flp]

This is just a different method of sharing spectrum among different users. The currently used methods are pretty good. They have been under development for about 100 years. The Rf spectrum is a limited resource. The amount of information that can be transmitted over the spectrum is limited by Shannon's theorem (read his 1949 paper). This limit can't be increased. What UWB does is spreading its information over really wide bandwidth, raising the noise floor for everybody else. If there are enough UWB transmitters around, they will interfere with each other to the point of uselessness. Also, this will f**k up every other user of the Rf spectrum. In addition, with UWB, the spectrum can't be managed by assigning different frequency bands to different entities. Everyone jsut uses all of the spectrum all the time. The strongest transmitter wins. Sounds like this technology has a good chance of being approved in the US...