Indian Journal of Science and Technology

Abstract

Background: Overlay based Cognitive radio can utilize only the primary user spectrum opportunistically for transmission. A hybrid overlay and under based cognitive radio is presented with game theory based decision making to facilitate continuous transmission support for the secondary user. Methods: The Hybrid Cognitive Radio (HCR) provides an optimum solution for effective utilization of the spectrum. A hybrid cognitive radio is designed to switch between overlay and under lay mode of transmission to continuously provide transmission opportunity with high data rate support for secondary user. The switching between the two transmission modes and frequency selection is formulated as a game. Decision making in the game is carried out by using the frequency utilization factor of the primary user as the utilization function of the game .Spectrally Modulated Spectrally Encoded (SMSE) framework is employed to efficiently generate the overlay Orthogonal Frequency Division Multiplexing signal and underlay Multicarrier Code Division Multiple Access (MCCDMA) signal with less overhead. Findings: This simple game theory based hybrid cognitive radio show improved bit error rate and throughput performance of the secondary user. The implementation of the hybrid cognitive radio is done using the LabVIEW and Universal Software Radio Peripheral (USRP) Software defined radio hardware platform. Applications/Improvements: The overhead of generation two different waveform in hybrid cognitive radio using Fast Fourier Transform (FFT) is reduced by sharing the common functionality between them under the frame work of the Spectrally Modulated Spectrally Encoded scheme which reduces the switching time and increases the spectral efficiency.

Keywords: Cognitive Radio, Game Theory, Hybrid Cognitive Radio, LabVIEW, Overlay, SMSE, Spectrum Hole, USRP, Underlay