Two novel blind CFO estimation techniques for CP-OFDM

In this paper two new Cyclic Prefix (CP) based blind Carrier Frequency Offset (CFO) estimations for Orthogonal Frequency Division Multiplexing (OFDM) transmission over multipath channels are proposed. In doing so, we first estimate the maximum delay of the fading channel. We borrow the concept of remodulation introduced in earlier works and use the repetitive structure of CP to calculate a maximum-likelihood-based measure. In the first proposed method we use Particle Swarm Optimisation (PSO) aided search on all possible samples to find the optimal set. This technique provides performance improvement at the expense of more complexity. Then, in a second proposed method we average over the optimal set of samples to estimate CFO. The second technique provides a major improvement over previous works while offering less complexity. Simulation results corroborate that both our proposed methods significantly decrease the Mean Square Error (MSE).