Orthognal Frequency Divison Multiplexing (OFDM) has been adopted by many high speed transmission standards.Pilot tone assisted modulation (PTAM) is well known technique to achieve timing synchronization information in OFDM but is not bandwidth efficient.To achieve high bandwidth efficiency

we proposed to carry out sperimposed a transparent genralized chirp-like (GCL) training with lower power in the guard band onto the time domain to improve the timing synchronization quality.The power ratio of the GCL sequence is determined by minimizing the system bit error rate (BER) using simulation experiments.Simulation results demonstrate that under medium to low SNR conditions

combing superimposed training with synchronization yields BER performance that is comparable with PTAM;the benefit of the former is that bandwidth efficiency is preserved.