Research On Pseudocode Capture Technology Based On Dynamic Spectrum Access In Hybrid Spread Spectrum Communication

Cognitive radio(CR)technology intelligently learn and adjust its parameters to achieve the purpose of sharing the spectrum,by sensing the spectrum environment.This spectrum sharing technology,on the one hand can improve the spectrum efficiency,on the other hand,when it encounters interference signals can automatically select the transmit power,channel and modulation methods of communication parameters to improve anti-jamming capability.Dynamic Spectrum Access(DSA)is one of the key technologies of cognitive radio technology,DSA can effectively use spectrum holes to ease the shortage of spectrum issues.Hybrid spread spectrum has many advantages,such as low probability of interception,strong multiple access capability,strong anti-jamming capability,strong anti-multipath capability and good security.Hybrid spread spectrum technology to achieve dynamic spectrum access is the best way.The main research work and contributions are as follows:1?This paper presents a DS/FH hybrid systems based on CR technology,and does some modeling and analysis.First,this paper derives underlay waveform expression based on DS/FH hybrid spread.Then,this paper has been modeled on specific interference in system,such as the primary user interference to the second user,the secondary user interference to the primary users.Finally,this paper simulates the interference suppression algorithm based on FFT lapped transform,and analyzes the pseudo-code acquisition performance under narrow-band interference signal.2?This paper analyzes and improves the PMF-FFT algorithm,and gives optimized PMF-FFT algorithm for FPGA implementations.First,since the transmission signal is affected by the channel,this paper has been improved scallop loss and optimized frequency domain attenuation on PMF-FFT algorithm for frequency offset conditions.Then,this paper gives an FFT-based Cordic comprehensive optimization of PMF-FFT FPGA implementation,and introduces the implementation process of the main module design and simulation results.Finally,this paper does a top-level simulation to verify the correctness of the capture algorithm,verifies the optimal results of PMF-FFT algorithm,and derives an average acquisition time.