Research On The Papr Reduction Algorithm In FBMC-OQAM System

In recent years,Filter Bank Multicarrier based on Offset Quadrature Amplitude Modulation has attracted the attention of scholars.FBMC-OQAM technology has the advantage of low sidelobe,high spectral efficiency,and no need of cyclic prefix(CP)by improving the prototype filter.However,the problem of high PAPR is ubiquitous in multicarrier systems.Since the FBMC-OQAM system uses a non-rectangular filter and offset quadrature amplitude modulation technology,which results in the superimposition of timedomain signals,the traditional algorithm of reducing the peak-to-average ratio cannot effectively reduce the PAPR of the system if it is directly applied to the FBMC-OQAM system.In response to this problem,this thesis mainly studies the algorithm that can effectively reduce the peak-to-average ratio in FBMC-OQAM system.The specific research contents are as follows.First of all,aiming at the unavailability of traditional algorithm of tone reservation(TR)in FBMC-OQAM system,this thesis introduces a Blocks Tone Reservation with Smart Gradient Projection(BSGP-TR)algorithm for FBMC-OQAM system.The core idea of this algorithm is to consider FBMC-OQAM symbol as a whole firstly,then block the symbols that are superimposed on each other to make them become independent data blocks,so as to eliminate the peak hyperplasia caused by signal overlap.Due to the shortcomings of traditional TR algorithm,such as slow convergence speed and high complexity,the convergence speed of TR algorithm is further improved by combining intelligent gradient projection algorithm(SGP)in audio processing,which reduces the computational complexity of the algorithm.Theoretical analysis and simulation results show that BSGP-TR algorithm can effectively reduce signal PAPR in FBMC-OQAM system and has a faster convergence rate.Secondly,aiming at the problem of high complexity of PTS algorithm,by improving the traditional PTS algorithm,a low complexity PTS algorithm based on peak estimation(PE-PTS)is proposed.The core idea of the algorithm is to estimate the minimum peak power of the FBMC-OQAM signal and to remove the sampling points of the original signal whose power is less than the minimum peak,so as to reduce the number of sampling points that multiplied by the phase rotation when calculating of each candidate signal,which greatly reduces the complexity of obtaining candidate signals and calculating their PAPR.Theoretical derivation and simulation show that PE-PTS algorithm can effectively reduce the PAPR of FBMC-OQAM system and has very low computational complexity.