Cognitive Technology for improving Ultra-Wideband (UWB) Coexistence

Cognitive radio technology enables the opportunistic operation of secondary devices in frequency bands allocated to primary users. In this paper we explore how this technology can enable ultra-wideband (UWB) systems to coexist with primary users. The distinguishing aspect of cognitive radio technology is the ability to detect and avoid primary users. We discuss two options for detecting the presence of primary devices - energy detection and preamble detection. The presence of multiple UWB devices can aid detection by enabling cooperative sensing of the primary. We analyze various techniques for cooperative sensing which differ in the amount of information they need to exchange between radios and the regime in which they are potentially advantageous. Furthermore, the wideband aspect of UWB offers many challenges to detection but also facilitates the detection process in several ways. These distinguishing aspects of wideband detection are also highlighted in this paper.