Future wireless systems: UWB, 60GHz, and cognitive radios

There are a number of new radio systems which exploit novel strategies being made possible by the regulatory agencies to increase the availability of spectrum for wireless applications. Three of these that will be discussed are Ultra Wideband (UWS), 60 GHz and cognitive radios. The UWB approach attempts to share the spectrum with higher priority users by transmitting at power levels that are so low that they do not cause interference. On the other hand, Cognitive radios attempt to share spectra by introducing a spectrum sensing function, so that they are able to transmit in unused portions at a given time, place and frequency. Another approach is to exploit the advances in CMOS technology to operate in frequency bands in the millimeter wave region. 60 GHz operation is particularly attractive because of the 7 GHz of unlicensed spectrum that has been made available there