An efficient technique for the integer frequency offset estimation in OFDM systems

This communication proposes a novel null subcarrier based algorithm for the integer frequency offset (IFO) estimation in orthogonal frequency division multiplexing (OFDM) systems. Bandwidth overhead of the proposed algorithm is less than 5% of the bandwidth of first OFDM symbol in a frame. The IFO is estimated by computing the energy of subcarriers at the DFT output just once and by finding the shift in null subcarrier indices using a simple statistical approach. The proposed method is computationally very efficient as compared to the methods which use exhaustive search procedures. It also achieves advantages over a few recently published methods in terms of the number of real additions (RAs) and bandwidth overhead required for IFO estimation. Computer simulation studies show that the estimator is able to achieve an IFO estimation range equal to the OFDM bandwidth.