UltraWideBand (UWB) and ZigBee
Like WiMax, neither UWB, nor ZigBee are suited for building a wireless LAN. But you hear about them a lot, so here are a few key factoids.
Although this technology has been around since the 1960's, UWB has captured the imagination of many who closely follow the wireless networking market. But some of the initial buzz is fading as the first UWB devices hit the market in early 2006.
UWB employs spread-spectrum technology, in perhaps its most extreme form. UWB signals look more like noise than typical modulated radio signals since they are spread out over several GHz and operate at low power levels. The technology has been controversial, however, with some groups concerned that the signals could interfere with other wireless services.
Despite these concerns, the FCC approved UWB for commercial use in late Feb 2002. In a nod to the concerns mentioned above, however, the FCC set limits on the frequencies that UWB devices could use, avoiding frequencies used by the military and GPS devices. Power levels were also limited to keep useful operating range down to about 10 Meters / ~33 feet.
But similar to the battles over the 802.11n standard, UWB has had a difficult birthing process. At the beginning of 2006, the working group for the relevant IEEE standard, 802.15.3a, gave up trying to fight the warring UWB Forum and WiMedia Alliance industry groups and voted to disband. The result is that members companies of both groups are moving forward with bringing non interoperable products to market.
And to make matters worse, the first products from both groups are aimed at eliminating USB cables. "Cable-free USB" products based on technology from Freescale Semiconductor (in the UWB Forum camp) will hit in late spring this year (2006). Then "Wireless USB" products from WiMedia alliance member companies are expected to follow in the second half of 2006. (See this CES 2006 report). Both technologies are aiming at USB 2.0 speeds (480Mbps), but will be able to support single links only.
ZigBee is another "Personal Area Network" (PAN) Bluetooth-like technology, operating at about 1/4 Bluetooth's 1Mbps maximum data rate, and consuming very low power. The official IEEE 802.15 Task Group 4 website puts it this way:
... a low data rate solution with multi-month to multi-year battery life and very low complexity. It is intended to operate in an unlicensed, international frequency band. Potential applications are sensors, interactive toys, smart badges, remote controls, and home automation.
ZigBee is a ratified (released) standard and is finding its first applications in home automation, control and security applications
Recommendation: UWB and Zigbee are more of a threat to Bluetooth than Wi-Fi. Not suited for building a wireless LAN.