Some physical layer issues of wide-band cognitive radio systems

Recent study by FCC spectrum policy task force (SPTF) found that while the available spectrum becomes increasingly scarce, the assigned spectrum is significantly underutilized. Cognitive radio technology holds the key promise to solve such problems. In this paper, we investigate some physical layer issues of wide-band cognitive radio systems. Specifically, we discuss the physical layer signal structure to support flexible operations required by wide-band cognitive radios. We analyze the performances of generalized power sensing and waveform sensing. And we study the adjacent channel interference mechanisms focusing on the interference caused by time-domain signal truncation