Abstract: The effect of timing offset on OFDMA signals is exploited and a least squares algorithm of timing offset is proposed for OFDMA uplink systems. The phase difference between the sub-carriers of pilot symbols is used to estimate the timing offset. Compared with the conventional algorithms, all the users’ timing offsets are estimated simultaneously and the algorithm suits both the interleaved OFDMA and the sub-band based OFDMA, providing a faster acquisition of synchronization with a lower complexity.

Key words: OFDMA, pilot, timing offset, least squares estimation