Detection of the guard interval length in OFDM systems

Orthogonal Frequency Division Multiplexing (OFDM) has attracted more and more interest in wireless multimedia broadband communications. The length of guard interval is a very important parameter in OFDM systems. The optimal value of this parameter varies as environment changes. In a traditional system, the transmitters need additional signals to inform the receiver when the parameter changes. In this paper, we propose a low-complexity method, which can detect the length of guard interval (GI) at the receiver without additional signaling. The introduction of this method reduces the additional signaling and thus simplifies OFDM systems. Both theoretical analysis and simulation result show that the proposed method has good performance. The detector designed according to the proposed method works almost ideal for Signal-to-Noise Ratio (SNR) values above 3dB over AWGN and Rayleigh Channels.