Double-threshold energy detection method based on history sensing information

Abstract

The invention discloses a double-threshold energy detection method based on history sensing information. According to the method, probabilities that states of occupying a licensed band by a licensed user are changed or not in adjacent sensing frames are estimated through an energy detection method; a high threshold and a low threshold satisfying constraint of a target false alarm probability are set according to a theoretical value of a false alarm probability and the probabilities; spectrum detection is carried out; and when an energy statistic value of a current sensing frame is greater than the high threshold, it is judged that the licensed user occupies the licensed band in the current sensing frame, otherwise, secondary judgment is carried out on the state of occupying the licensed band by the licensed user through utilization of the energy statistic values of the current sensing frame and a history sensing frame according to the high threshold and the low threshold. The method has the advantages that the constraint of the target false alarm probability is satisfied, a relatively high detection probability is obtained, the spectrum detection performance is improved, moreover, the complexity is low, the detection timeliness is relatively good, and the occupied system bandwidth is low.

Description

technical field [0001] The invention relates to a frequency spectrum detection technology in a cognitive radio system, in particular to a dual-threshold energy detection method based on historical perception information. Background technique [0002] With the rapid development of wireless communication technology, people's demand for spectrum is increasing. At present, most countries and regions still use a static spectrum allocation method, that is, a specific frequency band is assigned to a specific user, and other users are not allowed to use it. Therefore, the spectrum utilization rate of the wireless communication system is not high. To this end, a cognitive radio (Cognitive Radio, CR) technology has been proposed. Under the premise of not excessively interfering with the communication of authorized users, cognitive users can improve the spectrum utilization efficiency of wireless communication systems by using idle frequency bands. [0003] As a key technology in cogn...

AI Technical Summary

Problems solved by technology

Although the improved energy detection method only needs to know additionally the statistical values ​​of the sampled signal energy of the first few perception frames, the calculation complexity is low, but it only uses a threshold value in the second judgment. On the one hand, when the authorized user suddenly no longer When the licensed frequency band is occupied, the statistical value of the sampled signal energy of the perception frame of the cognitive user will decrease sharply, while the statistical value of the sampled signal energy of the previous few perception frames is relatively large, so the current perception frame is different from the previous few perception frames. The mean value of the energy statistics of the sampled signal may be higher than the threshold value and misjudgment occurs; The energy statistical value of the frame and the energy statistical value of the sampling signal of the previous perception frames are higher than the threshold value, and misjudgment occurs. Therefore, the improved energy detection method is likely to lead to a high false alarm probability, resulting in a decrease in spectrum sensing performance.

Images