Interference-Cancellation-Based carrier frequency offset estimation for OFDMA uplink transmissions

A carrier frequency offset (CFO) estimator was developed based on an interference cancellation scheme for an orthogonal frequency division multiplex access uplink. An initial CFO estimate was first obtained based on the received training signals at each user's prescribed subcarrier positions. Then, the received training signals were compensated by using the initial CFO estimates in the frequency domain and the multi-user interferences were estimated. Finally, the interference-cancelled training signals were used to reliably estimate each user's CFO. The CFO estimator performance was evaluated by the bit error rate performances of the CFO compensation-based receivers at the base station. Simulations show that with this optimal interference-cancellation-based CFO compensation receiver, the performance gain with the estimated CFO values is approximately 3 dB better at the 0.1 % bit error rate than the initial CFO estimates.