Eigenvalue-Based Reliable Spectrum Sensing Scheme for Cognitive Radio Networks

In cognitive radio, the secondary user (SU) can only utilize the spectrum hole with assurance of sufficient protection to the licenced primary user (PU). In this paper, a reliable spectrum sensing scheme based on eigenvalue of sample covariance matrix of received signal is proposed. The conventional energy-based detection method is highly vulnerable under noise uncertainty and eigenvalue-based method overcomes it. Also, the performance of existing eigenvalue-based scheme deteriorates at low signal to noise ratio (SNR). This degradation of performance at low SNR can be overcome by choosing optimum number of samples in spectrum sensing interval. Here, the optimum number of samples for given SNR is proposed, also the theoretical analysis and numerical formula for optimum samples are presented. The simulation results evidence the performance of proposed sensing scheme is better than existing eigenvalue-based method and conventional ED-based spectrum sensing methods.