A new scheme for preamble detection and frequency acquisition in OFDM systems

Abstract

In this contribution, we propose a novel scheme for time and frequency synchronization in OFDM systems. A differential modulation is indeed used to design two training symbols with appropriate properties used as a preamble for the detection of the frame start and for the recovery of the integral carrier frequency offset. The new scheme is compared to the well known algorithm of Cox and Schmidl, also using two training symbols, and found to outperform it especially in timing acquisition for both AWGN and Rayleigh channels. As a byproduct, an estimator for the channel power profile is obtained. All the derived estimators performance depend on the choice of the symbols involved in training. We here discuss the properties for optimal performance and compare the results for a set of Gold, Kasami and Zadoff-Chu sequences.