Transposed-Farrow-structure-based multirate filters for symbol timing synchronization in software defined radio (SDR)

In this paper, a symbol timing synchronizer, employing a modified transposed-Farrow-structure (TFS), is investigated for SDR applications. This modified TFS can perform the timing adjustment interpolation, sample rate conversion (SRC) and matched filtering at the same time. It can also be incorporated with the maximum likelihood (ML) timing estimator easily to form a feedforward structure in a natural way. By trading off flexibility, reconfigurability, performance and complexity, the proposed approach possesses advantages over the traditional synchronizers, which adopt separate matched and interpolation filters or polyphase filterbanks. The performance of the proposed feedforward synchronizer is equivalent to that of the traditional feedback timing synchronizer.