Research On Parameter Optimization Based Sensing Technology Of Cognitive Radio

Cognitive radio technology utilizes spectrum sensing to ?nd vacant spectrum re-source, namely"spectrum hole", to improve spectrum utilization. Spectrum sens-ing as a key technology of cognitive radio is responsible for sensing vacant spectrumresources, monitoring the activities of authorized users and so on. How to sense ac-curately and e?ciently has important in?uence on the performance of entire cognitiveradio system. This paper is mainly about sensing methods and sense mechanism.Cyclostationary feature detect method has good performance even in low SNRsituation, but its complexity is relatively high. In the paper, an improved cyclostation-ary feature detection method is proposed to reduce computational complexity and alsomaintain good performance, which is based on the optimal parameter selection strate-gy for choosing detection parameters of cyclic frequency and lag. Taking BPSK andQPSK signals as examples, the theoretical analyses are presented for how to choose theoptimal parameters and simulations are given to certify the correctness of the proposedparameter selection strategy and show the performance of the proposed method.Spectrum sensing mechanism is mainly used to control the physical layer spec-trum sensing method, including the selection of sensing modes, sense period and de-tection time. In practice, to ensure a certain probability of detection and false alarm,the signal to noise ratio decreased with the increase of detection time, a detection timeadaptive method based on double threshold detector is proposed to improve general?xed detection time method. In the sense period aspect, based on analysis of transmis-sion model of primary users and secondary users, a strategy to select sense period isproposed to balance system throughput and the collision with primary users. Simula-tions are given to verify proposed methods and show the good performance of them.