Exploiting Spatial Dimension in Spectrum Sensing Using a Sector Antenna: A Ray Tracer Based Analysis

Spectrum sensing plays a key role for radio resource awareness in cognitive radio. To enhance the capabilities of cognitive radio nodes, exploiting the spatial resource in addition to frequency and time resources seems reasonable. In this paper we investigate the impact of using the spatial information from a sector antenna on sensing reliability as well as on availability of opportunity for secondary communication in cognitive radio. A ray tracer is used for modeling the urban environment and for wave propagation simulation. The power angular profiles obtained at different locations are further processed with MATLAB using measured and analytical radiation beam patterns to evaluate opportunity and detection performance. The measured beam patterns are obtained from a sector antenna specifically devised for exploiting spatial resources, whereas the analytical patterns are obtained from mathematical expressions representing three dipole elements in a circular array. The performance is compared to that obtained with an omni-directional antenna. The results show that exploiting the spatial dimension in spectrum sensing in cognitive radio improves the performance in terms of increased opportunities for secondary communications as well as the better detection of primary signals.