Windowed OFDM for Spectrum Agile Radios

Cognitive and spectrum agile radios are being considered as future wireless communication systems. These systems will have the capability of sensing their environment for active primary users and adapt their transmit signal such that any harmful interference to primary users is avoided. This paper proposes the use of a wideband Windowed OFDM (WOFDM) system for the physical layer of spectrum agile radios. It is shown that by properly choosing the window the system can create very deep notches in its spectrum and, hence, avoid creating interference for the narrowband primary systems in its band. The performance of such WOFDM systems are also studied.