The Design And Implementation Of Cognitive Radio Systerr Based On GNU Radio And USRP

As the fast development of Mobile Internet,Internet Plus and IoT,the demand of wireless communication will be great.Due to current static spectrum allocation strategy,limited spectrum resource becomes the main factor constraining the development of wireless communication.With no interference to the authorized users,cognitive radio technology greatly improves the efficiency of spectrum utilization.It's the key technology of next generation wireless communication.Foreign study on the theory of cognitive radio is systematic.Some study teams even began the study of cognitive radio system design and builded research platform to take real-time test and verification.Domestic related research of cognitive radio theories also has been taken actively.With imperfection realization of cognitive radio system,there is need to design and build a cognitive radio research platform for theory study.The main work of this paper is building a cognitive radio system based on GNU Radio and USRP.By searching spectrum holes among licensed bands,it adaptively complete the cognitive communication with P2P.Firstly,this paper describes the software and hardware platform,which are GNU Radio and USRP.Then it describes the design of the whole cognitive radio system,which contains physical layer and MAC layer.The physical layer is based on using OFDM technology.Meanwhile,the design of sreambling/descreambling,Convolutional coding/Viterbi decoding,QPSK modulation/demodulation,OFDM modulation/demodulation,synchronization and channel estimation are based on modularize method.The MAC layer protocol of cognitive transmission includes spectrum sensing,adaptive channel selection and sense-transmission time allocation,they implement the function of channel sensing,spectrum pool management and sense-transmission time alloction respectively.It's the key technology of cognitive radio system,and achiving higher channel utilization but with limited interference to the licensed users.Simulation and test results illustrated that this system can identify idle channel by scaning spectrum pool.And it can transform datas correctly through the idle channel,with the dynamic management of spectrum pool.Under certain performance,system capacity is improved efficiently.This provids a platf'orm for future research.