Directional cyclostationary feature detectors using 2-D IIR RF spiral-antenna beam digital filters

Cognitive radio relies on accurate spectrum sensing for increasing the spectral efficiency of wireless networks. A novel array processing scheme is proposed based on a uniform linear array (ULA) of circularly-polarized spiral antennas having frequency range 2-6 GHz, which is used in conjunction with digital beam filters having 2-D IIR transfer functions for accurately and efficiently placing radio sources in wireless environment. Algorithms such as cyclostationary feature extraction is employed at beamformer to measure energy and realize feature/modulation detection, which in turn allows classification of a wireless environment. Simulation examples are provided for demonstrating the low-complexity directional feature detector with applications towards enhancing access to radio spectrum. Examples showing classification of sources by direction, frequency channels and modulation type in the 2-4 GHz band at SNR=6 dB are given.