Patent ID: 7894328

Claim:
A method for detecting mode and guard interval, comprising: receiving at least an orthogonal frequency division multiplexing (OFDM) symbol, which includes a guard interval with length N g , and a useful part with length N u , wherein the received OFDM symbol is in one of a plurality of modes in accordance with the length N u of the useful part, and having one of a plurality of guard interval ratios N g /N u in accordance with the length of the guard interval; performing a mode detection step for detecting the mode of the OFDM symbol, based on correlation of the OFDM symbol with respect to chosen one of the plurality of guard interval ratios; performing a guard interval ratio detection step for detecting the guard interval ratio of the OFDM symbol, based on correlation of the OFDM symbol with respect to all of the guard interval ratios; evaluating validity of the guard interval ratio detection step by comparing a timing deviation between two received OFDM symbols with a timing error tolerance constant; and repeating the mode detection step until an absolute value of the timing deviation is less than the timing error tolerance constant.