This paper describes how Cognitive Radio (CR) could benefit from Software-Defined Radio (SDR) compatible Ultra-Wide Band (UWB) systems. It introduces the notion of umbilical cord that can keep a CR device connected to its surrounding world, thanks to sensing and low speed over-the-air reconfiguration (OTAR) means provided by Low-Data Rate (LDR) systems, and to fast OTAR downloading facilities based on High-Data Rate (HDR) hot spots. A particular UWB architecture supporting SDR-compatible technological constraints is proposed as candidate to realize this promising combination of capabilities.
