Blind Synchronization Algorithms For OFDM/OFDMA Based On Cyclostationarity

Orthogonal frequency division multiplexing (OFDM) is a new modulation method for broadband mobile communications. Its principles, schemes and performance are illustrated in this thesis. The thesis also analyses the performance of OFDM systems affected by synchronization error. A blind synchronization method based on cyclostationarity is mainly studied.The blind synchronization method based on cyclostationarity is firstly analyzed in the downlink. Simulations of the method are carried out under different channel conditions. The performances of the method are analyzed, and then compared with the blind method based on the cyclic prefix of OFDM symbols, thus the validity of the method is proved. Then the proposed method is applied to the uplink of the multiuser OFDM (OFDMA). Two synchronization methods based on cyclostationarity are proposed here for two different subcarrier allocation modes. The simulation results demonstrate the good performances of the proposed estimators.