Blind CFO Estimation in OFDMA Uplink Transmission With General Carrier Assignment Scheme

Carrier frequency offset (CFO) estimation is a challenging issue in uplink orthogonal frequency division multiple access (OFDMA) systems. Most existing blind estimation methods for these systems are derived under certain types of carrier assignment scheme (CAS). In this letter, we propose a new blind CFO estimation algorithm for uplink OFDMA systems with constant modulus constellation. The proposed estimator can estimate CFO under any type of CAS, with only one antenna at the receiver. Moreover, the proposed method can be applied to OFDMA with or without virtual/null subcarriers. Simulation results show that the proposed estimator performs well under arbitrary CAS.