Low complexity blind residual carrier offset estimation in OFDM-based wireless LAN systems

In Liu and Toreli (1998), a blind carrier frequency offset (CFO) estimation method was proposed for orthogonal frequency multiplexing (OFDM) systems. This method makes use of the fact that in practical OFDM systems, there are some subcarriers that do not carry any data. However, the computation complexity of the method is rather high. In this paper, based on practical considerations, we propose a low complexity blind CFO estimation method. We derive an approximate closed-form solution for the CFO estimate. We show that the proposed algorithm achieves similar performance as the method in Liu and Toreli (1998) with significantly reduced computational complexity. For relatively large CFO values, we show that we could use the iterative algorithm in Wu et al. (2005) to improve the performance of the proposed algorithm.