Joint carrier frequency and symbol timing synchronization sequence for FBMC based system

Abstract

Filter Bank Multicarrier (FBMC) is a multicarrier scheme that employs shaping filter for improved spectral properties. In this paper, a low complexity data-aided symbol timing and carrier frequency offset synchronization technique for FBMC is presented for continuous mode transmission. Two training sequences based on Zadoff–Chu sequence are proposed. The first sequence is called the Long Sequence that takes 9 FBMC symbols, it avoids the interference with data symbols and the second is called the Short Sequence that takes 3 FBMC symbols, it is a modified version of the Long Sequence for better spectral efficiency. An autocorrelation-based synchronization metric is used that exploits the repetition of samples in the received training sequence. High peak is produced by the synchronization metric during reception of the training sequence compared to the metric values during reception of data samples. This makes it easy for the receiver to recognize the training sequence and to perform the related estimates of the symbol timing and carrier frequency offset. The training sequence is also used for channel estimation. The performance was evaluated under different channel conditions for two different shaping filters.