Spectrum sense utilizing multi-antenna beams scanning in cognitive radio networks

Spectrum sensing is one of the most important functions for cognitive radio. The performance of some sensing techniques like energy detection is determined by receiving signal to noise ratio (SNR). We applies antenna array using multiple beams to primary user detection. Whole space around cognitive user is divided into several subspaces for multiple beams. The directional beam can improve spectrum sensing performance by increasing receiving SNR. Moreover the approximate direction information of primary user can also be acquired after sensing. The beamformer used here doesn´t require channel information and is pre-specified without much computation. The mathematic analysis is given for energy detection using directional beam under different channels. The simulation results prove the performance promotion.