Research On FB-OFDM Multi-carrier Technology In 5G Mobile Communication System

OFDM technology is widely used.It has the advantages of high spectral efficiency,strong anti-interference ability,and low complexity of the transceiver.However,at the same time,there are serious problems such as out-of-band leakage and high synchronization requirements.Under the new requirements of the future,these shortcomings make it difficult to meet the demand.The filter bank OFDM techno logy(Filter Bank-OFDM),as a key alternative multi-carrier technology in the fifth generation of mobile communicatior,has been paid more and more attention in the industry and abroad.The technology can well solve the problem of low spectrum utilization efficiency in the OFDM system;it does not need to use the CP to occupy extra bandwidth to combat the ISI;it can flexibly switch different waveform functions according to the service requirements of different scenarios to adapt Different business scenarios.Therefore,the research on FB-OFDM technology is of great significance.The paper first introduced the basic principles of FB-OFDM technology in detail In the FB-OFDM technology,a new waveform function and IOTA function based on the root raised cosine function are used.Both waveform fanctions have good frequency domain characteristics and time domain characteristics,and can improve the utilization of the frequency band.It is very good.Options.Using a polyphase filter to filter each subcarrier in the entire bandwidth,the out-of-band attenuation of each subcarrier can be increased by 20dB,which effectively suppresses out-of-band leakage.After studying the frame structures of LTE,three sub-frame structures suitable for FB-OFDM are proposed,and the performance of three sub-frames is analyzed.This article uses simulation tools to achieve and strictly analyze the performance of FB-OFDM multi-carrier technology,using FB-OFDM system using two waveform functions respectively compared with OFDM systems,from the sub-carrier power spectral density,bit error rate and other aspects of analysis,the results It shows that sub-carriers have significant out-of-band attenuation after passing through a polyphase filter,and the use of multiplewaveform functions can meet the requirements of different service scenarios.It is a multi-carrier technology that can be applied to 5G mobile communication systems.For the problem of peak-to-average power ratio in FB-OFDM systems,based on the traditional peak clipping algorithm,an improved baseband intermediate frequency joint peak clipping scheme is proposed.Based on the three performance indexes,the peak clipping scheme is verified by simulation.The results show that with this new peak clipping scheme,the system PAPR improves significantly,the degree of EVM deterioration is small,and the ACLR improves significantly.