08-17-2017, 12:22 AM
INTRODUCTION
The average person has a small home, but a huge appetite for entertainment. All of us would want to zap video images from digital camcorders to our hard drives without tripping over the cables that connect them. As home entertainment systems become more sophisticated, u will have flat panel displays. You could hang them like paintings on your wall ..Now who would want cables to dangle from those beauties?
So you think - big deal . We have Bluetooth and 802.11 wireless technologies to solve this problem. They do a decent job of linking our pc s and digital gadgets in the home and office. However, more bandwidth and speed is always welcome. Its here that UWB makes its grant entrance.
UWB can handle more bandwidth intensive applications such as streaming video than any 802.11 or Bluetooth technology. It has a data rate of roughly 100 Mbps. Compare that with the maximum speeds of 11 Mbps for 802.11b, called Wireless Fidelity or Wi-Fi, which is the technology currently used in WLANs (wireless LANs). Bluetooth has a data rate of about 1 Mbps. UWB is expected to reach around 500 Mbps by 2004.
Propagation environments place fundamental limitations on the performance of wireless communications systems. The existence of multiple propagation paths (multipath), with different time delays, gives rise to complex, time-varying transmission channels. A line-of-site path between the transmitter and receiver seldom exists in indoor environments, because of natural or man-made blocking, and one must rely on the signal arriving via multipath.
UWB gives us these extremely high data rates at lower costs and lower levels of power consumption, which makes it ideally suitable for handhelds and mobiles.
What is Ultra Wideband technology?
Ultra Wideband is a revolutionary wireless technology for transmitting digital data over a wide spectrum of frequency bands with very low power. It can transmit data at very high rates (for wireless local area network applications). The approach employed by UWB devices is based on sharing already occupied spectrum resources, rather than looking for still available but possibly unsuitable new bands. Within the power limit allowed under current FCC regulations, Ultra Wideband can not only carry huge amounts of data over a short distance at very low power, but also has the ability to carry signals through doors and other obstacles that tend to reflect signals at more limited bandwidths and a higher power. At higher power levels, UWB signals can travel to significantly greater ranges. Instead of traditional sine waves, ultra wideband broadcasts digital pulses that are timed very precisely on a signal across a very wide spectrum at the same time. Transmitter and receiver must be coordinated to send and receive pulses with an accuracy of trillionths of a second.
UWB is not a new technology. Dr. Gerald F Ross had demonstrated its potential in radar and communications in the early 1970s itself. However, its usage for wireless applications, particularly for WLANs and WPANs, began only in the late 1990s with several players like XtremeSpectrum, Time Domain, Multispectral Solutions, Aether Wire, Fantasma Network, IBM, Intel and Motorola.
UWB was also used in espionage agencies in both the United States of America and the former Soviet Union. The research of military radar technicians led to the ultra wideband synthetic aperture radar , used by spy planes and satellites to see through dense ground cover to locate enemy troops and camouflaged equipment on the ground. It works by showering the target with rapid pulses of broad, low frequency signals that punch their way through solid objects. UWB works in a similar fashion.
How secure is UWB?
UWB promises to be highly secure. It s very difficult to filter a pulse signal out of the flood of background electronic noise with traditional RF scanners. Besides, vendors such as Time Domain are encrypting the zeros and ones being transmitted by the pulses.
If an intruder could find the signal in the noise floor, maintaining precise synchronization with a series of pseudo-random pulses of energy present less than 10% of the time and less than 500 picoseconds in duration is a monumental engineering challenge.
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