A Two-Stage Spatial Spectrum Sensing Scheme Based on Angle of Arrival Estimation

In this paper, a two-stage spectrum sensing scheme based on angle-of-arrival (AoA) estimation of multiple primary users is proposed. In the proposed scheme, the delay-and-sum beamformer is adopted at the first stage to determine the presence of the possibly existing PUs and their approximate AoA information. At the second stage, from the AoA of each being determined PU, the MUSIC spectrum is scanned in a small region around the estimated AoA to obtain accurate AoA estimates of possibly more nearby PUs that could be hidden at the first stage. Simulation results and complexity analysis show that the proposed method has better performance without increasing computation complexity, as compared to the central-symmetry-based feature detection method.