Design Of FPGA Algorithm For Spectrum Segmentation And Signal Reconstruction And Implementation Of Wireless System

With the deployment of the fifth generation(5G)mobile communication technology,the large-scale popularization of the Internet of things and the massive growth of other online services that occupy a lot of bandwidth,the future development of wireless communication systems will be restricted by the lack of spectrum resources,as well as the challenges of improving anti-interference capability while improving modulation efficiency.In such a case,the filter bank multi-carrier technology(FBMC)combining cognitive radio technology with spectrum segmentation,scrambling and aggregation can effectively solve these two difficulties,but there is a lack of practical low-complexity hardware implementation solutions,and the existing solutions focus more on the frequency domain signal processing and implementation of DSP.Aiming at the problems of too complicated FPGA implementation,resource consumption and delay in frequency domain signal processing implementation of spectrum division and aggregation algorithm,this paper uses finite impulse response(FIR)filtering in time domain to replace frequency domain filtering,designs a low complexity FPGA processing framework of spectrum segmentation and signal reconstruction based on time domain,and uses phase-locked loop group to estimate and compensate the frequency offset and phase offset of each sub spectrum,which better solves the multi-sub-spectrum synchronization problem of the system.Under the premise of high communication performance,the FPGA resource consumption of the system is greatly reduced,and the hardware requirements for system implementation are reduced.The main contents of this paper are summarized as follows:(1)Firstly,the research background and significance of spectrum segmentation and signal reconstruction filter bank algorithm in cognitive radio are discussed,as well as the development status of filter bank multi carrier technology and related system hardware implementation at home and abroad.Secondly,the principle,model and advantages and disadvantages of spectrum division and signal reconstruction filter bank based on frequency domain editing are summarized,and its key technologies(division aggregation filter bank design,frequency and phase distortion estimation and compensation)are simulated,analyzed and verified.(2)Aiming at the difficulty of multi subspectral synchronization in spectrum division and signal reconstruction communication system,a multi subspectral synchronization scheme based on phase-locked loop group is designed,that is,the phase-locked loop group is used to estimate and compensate the frequency offset and phase offset of each subspectral,and complete the digital down conversion and the same step,bit synchronization and frame synchronization between subspectral frequencies.Theoretical derivation and simulation verify its feasibility.The results show that the synchronization scheme has good synchronization performance and low implementation complexity.(3)In view of the high complexity of FPGA implementation of the current spectrum division and signal reconstruction system implemented in frequency domain,a low complexity FPGA implementation framework based on time-domain FIR filter for division and aggregation filtering is designed,the time-domain filter bank structure of the spectrum division and signal reconstruction system is deduced,and the implementation framework of the system was given.According to calculation,the implementation framework realizes low algorithm complexity FPGA resource consumption and delay.(4)In order to verify the effectiveness of the implementation scheme of spectrum division and signal reconstruction system based on time domain filtering,a software radio(SDR)verification system composed of FPGA baseband processing board and RF front end(ad9361)is built.On this system,the implementation framework of spectrum division and signal reconfiguration communication system based on time domain filtering is designed,implemented and verified,and compared with the theoretical simulation results of MATLAB.Through the relevant simulation and measurement,its performance advantages in the comprehensive accuracy of synchronization and sub spectrum analysis,FPGA resource consumption and final reconstruction demodulation are verified.