Adaptive Energy Detection Algorithm Based On Spectrum Correlation

With the rapid development of communication technology,the available wireless spectrum resources are becoming increasingly scarce.Cognitive radio using dynamic spectrum access strategy is considered to be an important means to solve the scarcity and low utilization of spectrum resources.Spectrum sensing technology is the key technology in cognitive radio.Energy detection algorithm becomes the most commonly used spectrum sensing method because of its low computational complexity and no prior information.This paper mainly studies how to use the energy detection algorithm to detect the low SNR signal effectively in the multi bandwidth signals scene.The detection performance of traditional energy detection algorithm under the condition of low SNR is not ideal.The energy detection algorithm based on spectrum correlation provides an effective solution for improving the detection performance of low SNR signals by using the correlation of signals.Combined with the above information,,the main research contents and innovations of this paper are as follows:1.Research on the theory and performance of energy detection algorithm based on spectrum correlation.The spectrum correlation method uses the spectrum correlation of signal frequency points through the joint determination of multiple frequency points.Compared with the traditional energy detection algorithm,the detection performance is significantly improved.However,when the SNR is further reduced,the detection ability basically fails.After studying the variables that restrict the detection performance of the spectrum correlation algorithm,the optimal spectrum correlation parameters are given for different SNRs.Ensure that the signal can be effectively detected even if the SNR of the signal is very low when the bandwidth requirements are met.2.The algorithm of SNR estimation based on inflection-point.It is necessary to select the best spectrum correlation parameters according to the SNR.The energy detection algorithm based on spectrum correlation belongs to blind signal detection,which can't get the SNR information in advance.In this paper,an algorithm of SNR estimation based on inflection-point is proposed.In this method,four inflexion-points are calculated at the candidate signal,among which the passband of the signal is between two and three inflexion-point,and the outward part of the first and fourth inflexion-point is the stopband.Finally,the SNR information of the candidate signal and the noise power estimation are obtained.3.Adaptive energy detection algorithm based on spectrum correlation.After synthesizing the optimal spectrum correlation parameters corresponding to SNR and the algorithm of SNR estimation based on inflection point,an adaptive energy detection algorithm based on spectral correlation is proposed.This method first uses inflection-point method to find out all candidate signals,then uses the corresponding optimal spectrum correlation parameters to detect the candidate signal.The false alarm rate is reduced by removing the noise part of the signal,and the final detection results is obtained.Simulation results show that the performance of the adaptive method is better than that of the existing energy detection algorithm based on spectrum correlation.