Iterative Frequency Domain Maximum Likelihood OFDM Carrier Frequency Offset Estimation

In this paper we propose an iterative frequency domain maximum likelihood carrier frequency offset estimation algorithm. It exploits only the available pilot grid that is used for channel state information estimation without any additional pilot overhead requirements. Maximum likelihood estimation in frequency domain using non-sequential pilot symbols significantly improves estimation quality. The solution is in closed form and it does not require computationally demanding exhaustive search. The proposed algorithm provides high resolution estimates of carrier frequency offset with moderate computational complexity. We also derive a Cramer–Rao lower bound that corresponds to a general scenario of arbitrarily spaced pilot symbols.