A simple feedforward timing offsets estimation algorithm for BPSK/QPSK

It has usually been used under feedback (FB) mode since Gardner timing-error detection algorithm (GTDA) was proposed. In this paper, GTDA is applied to the feedforward (FF) mode and its performance in this case has been investigated. A simple and effective feedforward timing offsets estimation algorithm for BPSK/QPSK is proposed based on T/4 spaced sampling and GTDA. Combining the coarse estimation with fine estimation and using linear function to approximate the central segment of GTDA around its zero point, the algorithm can be applied in both data-aided (DA) mode and decision-directed (DD) mode at low SNR. Simulation results are compared with the lower bound CRLB_DA under DA mode and the lower bound modified CRB (MCRB) under DD mode.