Research On Adaptive Transmission Technology Based On F-OFDM System

In recent years,on the basis of the demand for high connection efficiency of mobile terminals in the 5th generation(5G)of communication,the new air-interface waveform technology--Filtered Orthogonal Frequency Division Multiplexing(ability)has attracted significant attention.Besides,compared with the traditional OFDM technology,there are a lot of advantages such as higher bandwidth efficiency,excellent ability of adaptive,higher throughput,good ability of reducing the out-of-band leakage of spectrum and so on in this F-OFDM system.However,owning to the higher complexity in F-OFDM system,the achievement and application for 5G communication will be more difficult.Therefore,some works including the design of subband filter banks,the adaptive transmission and so on for the F-OFDM system have been investigated in our thesis,and the main contents are shown as follows:At first,the transmission process of baseband signal in the F-OFDM system has been introduced.Then,the difference and connection between the F-OFDM system and the traditional OFDM system have been analyzed.Moreover,the allocation scheme for multisubband time-frequency resource has also been researched,providing theoretical basis for the following studies?There are simulations in order to analysis the performance of F-OFDM system against carrier frequency offset,waveform parameter configuration and out-of-band leakage.The specific advantages of F-OFDM system as a new generation candidate air interface waveform are summarized.The key to F-OFDM systems is the design of multi-band filter banks.In this paper,a multiband filter bank based on cosine modulation technique is designed according to the requirements of specific stopband attenuation and reconstruction error.The filter bank design is based on the remez algorithm for prototype filter design,with low out-of-band leakage and low stop-band attenuation.The simulation analysis proves that receiver achieves near-complete reconstruction compared to the transmitter.Then,in order to achieve the goal of adaptive transmission of F-OFDM system,this paper studies the carrier frequency offset interference in the transmission,and derives the influence of frequency offset interference on the degree of out-of-band leakage between multiple sub-bands of the system.Deriving the results to optimize the design of the subband filter bank,in an effort to minimize out-of-band leakage.At the same time,considering the difference of the multi-channel fading degree,the adaptive equalization based on VS-NLMS algorithm is applied to the sub-band to compensate the channel and noise interference,The simulation results show that the reliability of F-OFDM system with adaptive equalization is improved.Based on the completed F-OFDM system theory,the Xilinx 7000 series ZC706 development board and the AD9361 RF transceiver module are used to develop and design the FPGA in the Vivado development environment.This paper mainly introduces the development and design of two parts.First,the multi-band filter bank is developed by the HDL language Verilog and ZC706 on the Vivado platform.The transmitter-side synthesis filter increases the transmission rate through the interpolator.The receiving end analysis filter recovers the data by downsampling.Second,the RF transceiver part of the F-OFDM system is realized by the Xilinx 7000 series ZC706 development board and the AD9361 RF transceiver module.The ZC706 is responsible for realizing the data stream transmission from the PC end to the FPGA board.The AD9361 RF transceiver module works in the ZC706 FMC.The module receives the data stream of the ZC706 and upconverts and transmits it to the wireless channel for transmission.After testing,the whole FPGA design can complete the transmission and reception of the data packet structure under the wireless channel,which basically meets the transmission requirements.