The OFDM demodulator is a complex system composed of many interacting components. The compensation of the delay introduced by the channel is achieved in three stages: coarse block synchronization for pre-FFT removal of the cyclic prefix, post-FFT fine block synchronization, and equalization. Solutions currently proposed in the literature for the cascade of pre-FFT block synchronization and post-FFT fine block synchronization introduce an additional time-varying delay, which can compromise equalizer's performance. Starting from this observation, a novel approach to post-FFT block synchronization is presented. The proposed approach has a major impact on the subsequent carrier phase tracking, thus motivating the design also of a new carrier phase tracking algorithm. The carrier phase tracking method proposed in this work is based on continual pilot tones, which are present in the DVB-T standard. Our simulations show that the proposed receiver architecture allows for a major performance improvement compared to classic systems.
['Mattia Speziali', 'Stefano Bregni', 'Maurizio Magarini', 'Arnaldo Spalvieri']
A new approach to post-FFT synchronization for DVB-T receivers