The emerging cognitive radio system can sense and adapt to the wireless environment in which it operates. Cognitive radio with intelligent capabilities of both radio link and network layers is capable of transmitting in an optimized way across the available signal dimensions allowing a potential huge increase in the prospects for spectrum efficiency, co-existence, compatibility and interoperabi...

Ultra Wide Band (UWB) technology is based on very short pulses of radio energy. In theory, its wide signal bandwidth yields excellent multipath immunity. Hence, UWB has been used in a variety of applications, including communication and ranging, and is expected to see increased use in the future. Since signals from GPS satellites have very low power levels (-130 dBm or -160 dBW) near the surfac...

Ultra wideband (UWB) wireless communication has been the subject of extensive research in recent years due to its potential applications and unique capabilities. However, many important aspects of UWB-based communication systems have not yet been thoroughly examined. The area of narrow band communication is well developed. The objective of this paper is to present Ultra Wideband (UWB) communica...

One of the potential benefits of the UWB radio is its multipath resolution. The implications are multipath components which might not be resolved as distinct arrivals in more narrowband systems, may be separately identified in UWB systems. This paper explores some of the propagation characteristics associated with UWB signals, based on measured data.

The application of ultra-wideband (UWB) technology to low-cost short-range communications presents unique challenges to the communications engineer. The impact of the US FCC’s regulations and the characteristics of the low-power UWB propagation channels are explored, and their effects on UWB hardware design are illustrated. This tutorial introduction includes references to more detailed explora...

Research in the design of ultra-wideband (UWB) radio systems suggests di erent kinds of signal design criteria. After an introduction to UWB radio, a variety of sequence design problems, motivated by UWB system constraints, will be presented. Design for time-hopping, for spectral atness, for rapid acquisition, and for multiple access will be discussed, and some sample designs will be presented.