In the uplink of orthogonal frequency division multiple-access (OFDMA) systems, before the data detection could be carried out, the carrier frequency offset (CFO) must be estimated and compensated to eliminate the inter-carrier interference (ICI) and multi-user interference (MUI), that is to restore the orthogonality among subcarriers. This paper proposed a novel pilot aided joint carrier frequency offset estimation and compensation algorithm for the uplink of OFDMA systems. By exploiting the pilot symbols, which are inserted for the purpose of channel estimation, (he algorithm realizes band efficient, joint CFO estimation and compensation without using channel information. This algorithm provides more accurate estimation since the data symbols and pilot symbols are in the same block, this is particularly important in a fast time varying environment. The computational complexity is greatly reduced by avoiding too much matrix inverse calculation. Simulation results demonstrate that the algorithm could achieve the Cramer-Rao Bound (CRB) with a few iterations at moderate SNR.
