Efficient Timing and Frequency Offset Estimation in OFDM Systems

Abstract

Orthogonal frequency division multiplexing (OFDM) is a bandwidth efficient modulation scheme used widely for high speed data communication. Fast and ro- bust synchronization algorithms are necessary for OFDM systems operating in burst mode like WLANs. In this paper, we propose an efficient timing and carrier frequency synchronization method for OFDM. The proposed scheme needs only one OFDM symbol for both symbol/frame timing and frequency offset estimation, while previous synchronization algorithms need more than two OFDM symbols as a training sequence. Numerical analysis shows that the proposed frequency estimator nearly achieves the Cramer-Rao lower bound for the variance of the frequency offset estimate, despite the reduction in the training sequence length.