Fast carrier frequency offset compensation in OFDM systems

Abstract

A new coarse carrier frequency synchronization algorithm is proposed that can estimate a coarse carrier frequency offset using only two symbols in the frequency domain for orthogonal frequency division multiplexing (OFDM) systems. The problem of conventional carrier frequency synchronization algorithms is that they require many symbols to compensate for a carrier frequency offset when the offset is close to +0.5 or -0.5, where the frequency is normalized to the subcarrier space. In contrast, the proposed algorithm estimates a coarse carrier frequency offset of around +0.5 or -0.5, thereby reducing the remaining carrier frequency offset to within -0.25/spl sim/+0.25. As a result, the proposed algorithm can significantly reduce the time required to synchronize a carrier frequency.