DETERMINATION OF THE THRESHOLD SOLUTION FOR A CHANNEL WITH RAY-LEIG FADING WHEN PROBING THE COGNITIVE RADIO ENERGY DETECTOR SPECTRUM

Spectrum sensor system performance and detection of spectrum band occupancy in cognitive radio are among of the main research aspects. When considering a system in which the primary user changes or there are multiple types of primary users, an energy detector is used. For energy detector operation, the main parameters that determine probabilistic characteristics of detection (probability of user detection, probability of a «false alarm» error and probability of a «missing target» error) will depend on the correct determination of the decision threshold. This article reviews an analytical approach to the normalized decision threshold determination. The purpose is to analyze and determine the optimal decision threshold value for an energy detector in a channel with Rayleigh fading. A spectrum sensing system in cognitive radio is considered. Normalized values of the threshold solution for a channel with Rayleigh fading are determined. Graphic illustrations of the analysis results and calculations are presented. Results obtained for determining threshold solutions may be considered a proper approximation for calculating the characteristics of sensing systems in cognitive radio in channels with Rayleigh fading, providing the opportunity to determine frequency bands free of primary users more likely, thereby increasing the efficiency of use of the radio frequency spectrum.