Frequency Domain Implementation And Performance Optimization Of Filtered-OFDM

In order to meet the future requirements for air interface waveforms in the fifth generation of mobile communications,such as lower out-of-band leakage,more flexible parameter configuration and support for asynchronous transmission,an improved scheme based on Orthogonal Frequency Division Multiplexing(OFDM)system—Filtered-OFDM(F-OFDM)system are proposed by Huawei.This scheme inherits all the advantages of OFDM system and reduces the out-of-band leakage effectively,but the higher complexity of time-domain filtering will greatly constrain future application in the next generation of communication networks.Aiming at those existing problems,the main contributions on F-OFDM system are shown as follows:1.Aiming at the high time-domain filtering complexity of F-OFDM,a frequency-domain optimization scheme FC-F-OFDM based on structure of fast convolution filter banks is proposed.The scheme composed of parameter configuration module ParSet,filter function module FC and prototype function module Taper,with the frequency bins as the unit,realizes a modular and parameterized F-OFDM system.Simulation results show that the FC-F-OFDM scheme has the feasibility of implementation in frequency-domain.Compared with the time-domain scheme,FC-F-OFDM occupies better performance of the anti-carrier frequency offset and greatly reduces the implementation complexity,but bad spectrum utilization.2.In order to further simulate the influence on the performance of FC-F-OFDM system caused by different parameters,the FC-F-OFDM system is simulated from four aspects: spectrum flexibility,MSE in data-segment,sub-band block error rate(BLER),and system power spectrum density(PSD).Simulation results show that FC-F-OFDM occupies stronger multi-parameters configuration flexibility facing to the multi-services,better transmission reliability in multi-path channels and good spectrum convergence when multi-user access.3.To meet the 5G requirement of the mixed numerologies(MN),the FC-F-OFDM scheme introduces the configuration of overlapping waveforms and realizes transmission of mixed waveforms simultaneously.The simulation results show that the FC-F-OFDM is feasible for configuration of overlapping waveforms,provides alternative waveforms,occupies good performance of spectrum convergence when simultaneously the mixed waveforms transmitted,and achieves the feature of the mixed numerologies.