Symbol synchronization based on cyclic prefix for the uplink of OFDMA systems

This paper addresses the problem of symbol synchronization for the uplink of orthogonal frequency division multiple access (OFDMA) systems over multi-path channels. An efficient two-step algorithm is proposed based on the redundancy introduced by the cyclic prefix (CP). The first step separates the signals corresponding to each user using the property of circular convolution. The second step individually estimates the timing offset for each user relying on the special structure of the correlation of the separated signals. Simulation results show that the proposed method outperforms the existing CP-based algorithms in multi-path channels and is robust to the range of the timing offsets and carrier frequency offset (CFO).