Ultra-Wideband (UWB) Radio: The Enabler for Pervasive Wireless Networking?
Original Publication Date: 2002-Jan-10
Included in the Prior Art Database: 2003-Jun-20
The Federal Communications Commission (FCC) released a Notice of Public Rulemaking (NPRM) on May 11, 2000 (FCC00-163,  aimed at amending the Commission's Part 15 rules to allow the use of new types of devices incorporating ultra-wideband (UWB) radio technology. This NPRM is a milestone for commercializing UWB radio technology and it could indicate the beginning of a new era for the wireless industry. Unlike conventional radio systems that emit modulated carrier frequencies within coordinated spectral bands, UWB devices emit sequences of widely separated individual pulses, or bursts of pulses, with a pulse width on the order of only one nanosecond or less. The average rate at which these pulses are emitted is specified by the pulse repetition frequency (PRF). Although a pulse's peak power may reach some tenths of a watt, the low duty cycle of UWB signals ensures that the emitted average power is significantly lower, on the order of one milliwatt or even microwatt. The pulses can convey information, for example, if their exact position is controlled in a way similar to pulse position modulation. Because the spectral bandwidth of such a pulse is essentially determined by the inverse of its width, typical UWB signals spread their energy over up to several GHz, yielding an extremely low emitted power spectral density such that UWB signals barely rise above the existing spectral noise floor. Properly designed UWB devices can meet the technical standards contained in the FCC's Part 15 rules. However, until an amended ruling is issued, such devices remain illegal because their use makes them intentional radiators as opposed to the various unintentional ones in existence (e.g., computers and electronic appliances). The FCC has already granted several waiver licenses to the industry for limited marketing of UWB devices and to academic institutions for experimentation , . Applications and Benefits of UWB Technology UWB proponents as well as the FCC believe that UWB devices may have the capability to provide significant benefits for public safety, businesses, and consumers  . The FCC further notes that UWB devices appear able to operate within the spectrum already occupied by existing radio services without causing interference, which would permit scarce spectrum resources to be used more effectively. UWB devices can be used for the precise measurement of distance or location and for obtaining images of objects buried under ground or building rubble as well as behind surfaces. Further applications are possible in biomedical telemetry, automotive proximity sensors (airbag release, traffic flow control) and inventory management (wireless tags). Moreover, devices based on UWB technology are claimed to be well suited for wireless communications, particularly for short-range data transmission as required for broadband access to the Internet or multimedia applications. In fact, UWB devices can be designed such that they provide modes for data communication as well as position location , , . 1