A novel frequency synchronization scheme for OFDM systems

A novel frequency synchronization scheme for orthogonal frequency division multiplexing(OFDM) systems is proposed,including a novel frequency offset estimation algorithm and a novel frequency offset compensation algorithm.The frequency offset estimation includes both the fractional frequency offset(FFO)estimation and the integral frequency offset(IFO)estimation.Firstly,the FFO WaSsobtained by the conventional ML algorithm in time domain.After the FFO was compensated in time domain,the IFO Was obtained by the proposed algorithm based on the energy of virtual carriers.This algorithm needs only simple calculations and has a large frequency offset estimation range.Furthermore,it is insensitive to symbol synchronization errors and channel changing.Finally,the IFO Was compensated based on the carrier-positions offset,which Can be completed through carrier-positions cyclic shifts in frequency domain.This proposed frequency synchronization scheme can decrease the system redundancy without any need of assistant data,and can be applied to the fast synchronization with the only need of one OFDM symbol.The analyses and simulations show the improved performance of the proposed frequency synchronization scheme.