Research And Implementation Of F-OFDM Filter Optimization Technology Based On FPGA

The fifth-generation mobile communication system(5G)can meet the higher performance requirements of modern communication due to its features such as fast download speed and ultra-low delay.In the aspect of waveform technology,Filtered-Orthogonal Frequency Division Multiplexing(F-OFDM)has become one of the candidates waveforms for 5G due to its good performance in suppressing spectrum leakage.F-OFDM has the advantages of conventional OFDM,but it still needs to be further optimized for its out-of-band radiation performance.This paper aims at the problem of the out-of-band radiation in F-OFDM.The design method of F-OFDM digital subband filter is mainly studied,and the filter design method based on the minimum out-of-band radiation criterion is proposed,and the filter design is optimized to reduce the out-of-band radiation of the communication system and improve the communication transmission performance.The implementation of F-OFDM filter is completed in FPGA to verify the effectiveness of the design.The main research contents of this paper are as follows:1.This dissertation studied the design characteristics of digital filters and F-OFDM system structure,studied the performance characteristics and various design methods and structures of FIR filters.The design method of filter window function is emphatically studied.2.By studying the basic principle and mathematical model of F-OFDM technology,and analyzing the advantages and disadvantages of the system,a design method of F-OFDM filter based on the minimum out-of-band radiation criterion is proposed to reduce the out-of-band radiation of the system;Fourier series was introduced to solve the numerical parameters of the filter,and the transmission performance of the filter designed by Hanning window and the F-OFDM filter based on the minimum out-of-band radiation criterion in terms of waveform,power spectrum and bit error rate curve were compared respectively.The computer simulation shows that the F-OFDM system based on the minimum out-of-band radiation criterion has better out-of-band radiation performance than the filter designed by Hanning window.3.By studying the influence of different n and m parameters on the design of F-OFDM window function based on the minimum out-of-band radiation criterion,a compromise was made between the out-of-band radiation performance of the filter,the difficulty of parameter calculation and implementation and the complexity of system implementation,and the approximately optimal design parameters of F-OFDM filter n=6 and m=6 were determined to meet the requirements of the system.Through computer simulation,the advantages and disadvantages of F-OFDM filters based on the minimum out-of-band radiation criterion under different n and m parameters are compared and analyzed,and it is verified that the optimal design parameters of F-OFDM filter have excellent out-of-band radiation performance.4.In the end,an F-OFDM system based on minimum out band radiation filter is implemented on FPGA,including F-OFDM receiver and transmitter.the synchronization and channel equalization of the communication system are realized,and the good simulation communication effect is achieved,which lays a solid foundation for the practical application of F-OFDM filter based on the minimum out-of-band radiation criterion.