OFDM carrier frequency offset correction based on Type-2 control loop

In this paper, we propose a robust data-aided carrier frequency offset (CFO) tracking algorithm for orthogonal frequency division multiplexing (OFDM) system. The problem is solved as a sequence of estimation and correction steps. We find the major contributors to the CFO measurement uncertainty are the additive white noise together with the inter-carrier interference (ICI). Our derivation results show the noise variance can be reduced via averaging while the ICI introduced uncertainty can be decreased by iterative CFO compensations. These considerations lead us to a Type-2 correction loop. Theoretical analysis and simulation results show our proposed algorithm is robust and able to compensate and track comparably large CFO.