Ultra-Wideband Communication Systems: Technology and Applications
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Editorial Ultra-Wideband Communication Systems: Technology and Applications Arne Svensson,1 Arumugam Nallanathan,2 and Ahmed Tewfik3 1 Department
of Signals and Systems, Chalmers University of Technology, 41296 Gothenburg, Sweden of Electrical and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 3 Department of Electrical Engineering, University of Minnesota, 4-174 EE/CSCI Building, 200 Union Street SE, Minneapolis, MN 55455, USA 2 Department
Received 31 December 2006; Accepted 31 December 2006 Copyright © 2006 Arne Svensson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Ultra-wideband (UWB) signals are defined to have a bandwidth of at least 500 MHz and/or a relative bandwidth of more than 20%. A signal with such a large bandwidth has some very unique properties like resistance to small-scale fading, good resolution for ranging and geolocation, and resistance to narrow-band interference. These signals can be used for transmission of extremely high-speed data or lowrate data with a large spreading factor. UWB communications have been investigated since the early 1990s, following the pioneering work of Win and Scholtz at USC. A major milestone for UWB deployment was the decision of the frequency regulator in the USA, the FCC (Federal Communications Commission) to allow unlicensed operation of UWB transmission subject to certain restrictions in the emission mask of the power spectral density. In essence, the FCC allowed intentional emissions in the frequency band between 3.1 and 10.6 GHz with a power spectral density of −41.3 dBm/MHz. This value agreed with the already existing regulations for unintentional emissions from electronic devices in that frequency range. Regulations in other countries were much slower in the making. Japan allowed UWB transmissions in the 3.1–4.8 and 6–10 GHz bands only in late 2006. A key requirement of the Japanese regulations is that, for frequencies between 3.1–4.8 GHz, UWB transmitters must employ “detect and avoid.” In other words, it is the duty of a UWB transmitter to detect a possible victim device and cease transmissions that might disturb such a device. Until 2010, the band between 4.1 and 4.8 GHz is exempt from this DAA requirement. European regulations are scheduled to be issued in the next years and are anticipated to be similar to the Japanese regulations. High-speed communications based on UWB were originally envisioned by the IEEE 802.15.3 standardization group,
which tried to establish a standard for short-range communications with rates in excess of 100 Mps. Though standardization within IEEE 802.15.3a failed, and the group ultimately dissolved, two major proposals for high-speed UWB communications emerged and were standardized by industry groups: multiband-OFDM (later-on adopted by the WiMedia Alliance and the European Computer Manufacturing Associat
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