Research On Energy Detection Of Spectrum Sensing Based On GNU Radio And USRP

With the push to “5G” cellular,the emergence of the Internet of Things(IoT),and numerous innovative radio-based services,the already crowded airwaves are becoming more congested.So it is critical not only that more spectrum be made available but also that existing spectrum use become more efficient.Cognitive radio technology can solve this problem effectively.This paper mainly studies energy detection spectrum sensing technology based on the software radio platform USRP.GNU Radio is an open source software system,it contains a lot of signal processing blocks.Through connecting USRP and PC with gigabit Ethernet,we can take a series of radio development operations,and design the communication system model conveniently and efficiently.The main work and innovation of this paper are as follows:Firstly,the energy detection spectrum sensing technology based on the Python framework is implemented on the USRP platform.The system makes full use of the GNU Radio,eliminating the need for third-party processing software,greatly reducing the computational overhead.We also introduce the process of the classic FFT module for fast Fourier transform to achieve spectrum sensing function.Secondly,a two-stage spectrum sensing scheme based on USRP is proposed and implemented.Respectively,the coarse scanning stage and the fine scanning stage.The coarse scanning can detect the spectrum occupancy in the 50MHz-2200 MHz band in real time and find the spectrum holes and the target signal.The fine scanning can accurately detect the center frequency and bandwidth of the signal in the specified frequency band,we can also observe the spectrogram of the signal.The coarse scanning can sweep wide spectrum band in a short time and the fine scanning can improve the detection accuracy.After the fine scanning stage,the USRP as a cognitive user can choose a reasonable frequency band to send data packets for spectrum access.By comparing the correct reception rate of the packet,selecting the correct frequency band through the spectrum sensing process will greatly reduce the bit error rate of the communication process.Thirdly,Design the USRP image transmission experiment with the primary user interference,and the effect of transmitting the image based on different spectrum sensing mode is compared,also the correct receiving rate of the image file is calculated.The two-stage spectrum sensing scheme based on coarsing scanning and fine scanning has the best detection effect.