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Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Editorial Ultra-Wideband Communication Systems: Technology and Applications | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2006 Article ID 16497 Pages 1-3 DOI 10.1155 WCN 2006 16497 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 2 Department 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 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 low-rate 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 .
