A combined timing and frequency synchronization and channel estimation for OFDM

The idea of combined timing and frequency synchronization and channel estimation is quite desirable since the synchronization and channel estimation tasks can affect each other. This paper addresses training signal based combined timing and frequency synchronization and channel estimation for OFDM systems. The proposed scheme consists of two stages. At the first stage, coarse timing and frequency offset estimates are obtained. Based on these estimates, a (coarse) channel response estimate is obtained. The timing and frequency offset estimates at the second stage are obtained by a maximum likelihood (ML) realization based on sliding observation vector. Then a ML channel estimation is performed. The simulation results show that the proposed combined approach performs quite well and circumvents the problem of mismatch among individual synchronization tasks.