| The filter bank multi-carrier offset quadrature amplitude modulation(FBMC-OQAM)signal has the characteristics of strong anti-fiber dispersion ability,high spectrum utilization,and low out-of-band power leakage.It is very advantageous in application scenarios such as mobile fronthaul network and passive optical network.However,the critical issue is the high peak-to-average power ratio,which degrades the performance of the system.This work proposes two methods for suppressing PAPR in optical FBMC system,and experimentally evaluates the performance of these methods.First,a selective mapping algorithm based on phase shift joint optimization is proposed.The conventional selective mapping algorithm has high complexity problem.In this paper,the computational complexity is reduced by shortening the calculation period of the average power and the phase conversion condition is introduced to change the processing object from complex data block to real data block to avoid signal distortion.Compared with the traditional dispersion selective mapping(DSLM)method,this method achieves similar PAPR suppression effect with better bit error rate(BER)performance.After a 3 0-km optical fiber transmission experiment,at the hard-decision forward error correction(HD-FEC)threshold the scheme achieves 1.5-dB improvement in receiving sensitivity compared to the DSLM.Second,the cyclic shift(CS)algorithm is proposed for the FBMC-OQAM system to reduce its PAPR.To solve the issue of data symbol superposition on the carrier of FBMC system,the cyclic shifts are introduced,where the real part and imaginary part carrier are cyclically shifted within the period T and T/2,which reduces the positive correlation between carrier signal overlap and high peak value.The traditional discrete fourier transform spread(DFTS)algorithm is classical to suppress PAPR in the multicarrier systems.In this work,the CCDF simulation and 30-km fiber optical fiber transmission experiment are implemented to evaluate the performance of the proposed CS.Compared to the conventional DFTS algorithm,the CS algorithm achieves a larger PAPR suppression,and at the HD-FEC threshold,the CS algorithm improves the 1.7-dB receiving sensitivity. |
