Research And Implementation Of Fast Spectrum Sensing System Based On Software Defined Radio Platform

Dynamic access technology of cognitive radio can effectively solve the problem of current spectrum scarcity,and has become a research hotspot in the field of wireless communication.Spectrum sensing is a prerequisite for cognitive radio systems.Based on an adaptive communication project in a complex environment,this paper develops the algorithm research and design of a fast spectrum sensing system based on software radio platform,in order to achieve the goal of fast and accurate sensing.Firstly,for fast sensing and accurate sensing,two spectrum sensing algorithms based on double threshold energy detection and support vector machine and cyclic spectrum feature are studied respectively.Spectrum sensing algorithm based on dual-threshold energy detection has low computational complexity,which can delay the judgement of sensing energy in fuzzy areas between thresholds to improve the performance of sensing.Spectrum sensing algorithm based on support vector machine and cyclic spectrum features has high sensing accuracy.Using the idea of machine learning,signal detection can be modeled as a classification problem.The first step is statistical learning,and then predictive classification.Secondly,the hardware platform and key technologies of the system are selected,analyzed,studied and applied,and the overall scheme of the system is worked out.Fast spectrum sensing system chooses pipeline hardware structure and FPGA hardware platform,which has high-speed signal processing ability and reconfigurable ability.The key technologies of system implementation include high-speed analog-to-digital converter interleaved sampling technology,high-speed signal processing parallel processing technology and high-speed data transmission PCIE technology.The overall scheme of the system is formulated on the basis of algorithm and key technology research.Finally,the simulation of the system and the verification of each unit's FPGA design are elaborated in detail.Modeling and simulation verify the feasibility of the system design;high-speed A/D conversion unit,baseband signal processing unit and high-speed data transmission unit respectively complete the fast acquisition,processing and transmission of signals;perceptual decision unit is divided into two perception modes: parallel scanning and serial scanning.The perceptual decision unit is designed and implemented on the basis of spectrum sensing algorithm based on double threshold energy detection,spectrum sensing algorithm based on support vector machine and cyclic spectrum characteristics.In this paper,the method of step by step analysis is used to simulate,test and verify the units and modules of the system,and verify the correctness of the functional link of the system on the hardware platform of software radio.