Research On Key Technologies Of F-OFDM For 5G

With the development of mobile Internet and Internet of Things in recent years,countries around the world have joined the research and development of broadband multi-scene communication represented by 5G.Enhanced Mobile Broadband,ultra Reliable&Low Latency Communication and massive Machine Type Communication are defined as the three major application scenarios of 5G.In order to better adapt to the performance requirements of each of the three major application scenarios,in terms of waveform technology,F-OFDM(Filtered-Orthogonal Frequency Division Multiplexing)has become one of the 5G candidate waveform technologies.F-OFDM can not only support a lot of application scenarios but also has the advantages of traditional OFDM.However,some performance still needs to be further optimized.This paper will focus on the design of digital sub-band filters,PAPR(Peak to Average Power Ratio)suppression algorithms and symbol timing synchronization algorithms for F-OFDM systems based on the performance requirements of the three major application scenarios of 5G.Firstly,because different application scenarios have different performance requirements for the system,but the current digital sub-band filter of each sub-band of F-OFDM is seldom properly designed according to the specific application scenario characteristics of each sub-band of the system.Therefore,this paper uses common window function characteristics combined with window function method to design corresponding digital sub-band filters according to the corresponding performance requirements of the three major application scenarios of 5G.Simulation results show that the digital sub-band filters designed in this paper play a good role in optimizing the performance of F-OFDM system.Secondly,aiming at the PAPR problem of F-OFDM system,this paper proposes a sub-optimal PTS(Partial Transmit Sequences)suppression algorithm based on iterative clipping filtering according to the characteristics of the three major application scenarios of 5G.The comparisons of simulation results show that the algorithm can improve the PAPR suppression performance of the system better.Then,aiming at the massive Machine Type Communication application scenario of sub-band 3,a moving average maximum likelihood synchronization algorithm based on improved CP(Cyclic Prefix)is proposed.Simulation results show that the proposedalgorithm is superior to the traditional CP-based maximum likelihood synchronization algorithm in multipath fading channels.In addition,according to the characteristics of the application scenarios the other two sub-bands of the system face,the Schmidl&Cox algorithm with low complexity and easy implementation is selected.Finally,in order to verify the feasibility of the algorithms above,a software defined radio platform is used in this paper to build a test and verification platform for the F-OFDM system with three sub-bands and single transceiver for the three major application scenarios of 5G,which can test and verify the improved algorithms.The test results show that the algorithms are feasible in the system.This paper takes the three major application scenarios of 5G as the application background.The improved algorithm and ideas of the F-OFDM system's performance optimization research can be used as a reference for the F-OFDM system's performance optimization research in other broadband multi-scenario communications.