Research Of Spectrum Sensing In Cognitive Radio Technology

As wireless technology is widely applied in mobile communication,public security and the radio and television,spectrum resource is becoming more and more nervous. Fixed spectrum allocation model does not provide more available bandwidth and higher spectrum utilization efficiency.Cognitive radio technology is considered one of the key technologies of dynamic spectrum accessing and to solve the problem of the lack of spectrum resource.The key problem of cognitive radio technology is how to accurately identify the spectrum holes and detect the primary users.Spectrum sensing is the key to solve the problem.Based on the summary of the existing spectrum sensing technologies and the advantages and disadvantages of local detection algorithms,we have proposed the improvement scheme of spectrum sensing.We mainly have studied the algorithms of fine/feature detection process and collabortion spectrum sensing. Main content as follows:1.We have studied local spectrum sensing technology of cyclostationary feature detection, analyzed the cyclostationarity of digital modulation signals,computer simulation was carried out,we also have distinguished the modulation types of several similar signals by computer simulation.2.A multi-antenna parameter estimation based on cyclostationary characters was proposed to improve the estimation preformance.We analyzed the cyclostationary of the combined the DSSS signal and estimated the carrier frequency,chip width.The simulation results showed that the method could take full advantage of multi-antenna spatial diversity provided to improve the performance of parameter estimation.3.We have studied the cognitive radio system of cooper spectrum sensing,verified the interrelationships among the largest throughput,the best spectrum sensinge time and the best number of cognitive users in cooperation spectrum sensing system.And we have proposed a way that combines throughput,sensing time and optimal method of deviation coefficient,simulation results showed that the proposed way could significantly reduce the spectrum sensing time, and improve spectrum efficiency. in the system.