OFDM synchronization scheme for the forward link of a fixed broadband satellite system

Abstract

This paper proposes an OFDM receiver for the forward link of a fixed broadband satellite system. Although the satellite channel is not frequency selective, OFDM could be preferred to single carrier waveforms if it allows to improve the system spectral efficiency. The possible gain would arise from the possibility to reduce the overhead in a non-frequency selective channel. The cyclic prefix, introduced to suppress inter symbol interference (ISI), or the pilots used to estimate the channel, are not necessary in such context. Nevertheless, a part of the overhead in OFDM-based systems is necessary for synchronization purposes. This paper focuses on this problem. We propose a complete synchronization structure essentially based on a non pilot aided algorithm, only requiring some reduced overhead for a first coarse synchronization stage. The performance of the proposed receiver is assessed through simulation results.