A New Timing Offset Estimation Algorithm Using Phase Difference Between Adjacent Subcarriers in Interleaved OFDMA Uplink Systems

A new timing estimator using phase difference between adjacent subcarriers is proposed for interleaved orthogonal frequency-division multiple access (OFDMA) uplink systems. The phase difference of adjacent subcarriers is represented as the summation of the information of timing offset which we want to estimate and the phase difference of channel frequency responses which can cause performance degradation. Thus, a method to reduce the phase difference of channel frequency responses is applied in time domain, and then timing offset information is estimated from phase difference in frequency domain. Simulation results confirm that the proposed estimator can decrease the mean square error (MSE) compared with channel impulse response (CIR) based method when the information of channel length is unknown.