An all-digital frequency synchronization scheme for OFDM systems

The main purpose of this paper is to study the frequency synchronization problem in OFDM systems. A new frequency synchronization method is achieved by means of an all-digital synchronization loop including acquisition and tracking modes. The frequency offset is estimated only once per frame. The acquisition algorithm is based on periodically inserted reference symbols, and the tracking algorithm on the cyclic prefix of the OFDM symbols. The algorithm performance is assessed in an AWGN channel with a low SNR value and in the presence of a timing inaccuracy. The simulations show that the algorithm is accurate and the suggested frequency synchronization scheme works well.