A synchronization circuit includes a correlator, an energy calculator, a post-processing unit, and a decision device. The correlator correlates a received sequence r(t) with a local sequence c(i) to obtain a correlation result h(t). The energy calculator calculates an energy function of the correlation result h(t), and filters the energy function of the correlation result by a channel impulse response wc(l) to obtain a filtered energy function e(t), where l is the index of the channel impulse response. The post-processing unit applies weighting function wa(t) to the filtered energy e(t) to obtain a weighted energy function e′(t), wherein the weighting function wa(t) weights a central portion of the filtered energy function e(t). The decision device selects a maximum energy value from the weighted energy function e′(t), and the time index t with maximum energy value is the time shift of the received sequence and the local sequence.