Patent ID: 7123662

Claim:
An OFDM detection apparatus for networking devices, comprising: a processing unit for taking a sample sequence from the beginning of a newly arrived network packet and outputting a first signal and a second signal, comprising: a first means for calculating a first correlation sequence between the complex conjugate of said sample sequence and said sample sequence with a first lag of N samples, where Nεpositive integer; a second means for calculating a second correlation sequence between the complex conjugate of said sample sequence and said sample sequence with a second lag of M samples, where Mεpositive integer and M≠N; a third means for evaluating first accumulative energy of said sample sequence with said first lag of N samples; a fourth means for evaluating second accumulative energy of said sample sequence with said second lag of M samples; a fifth means for asserting said first signal according to a comparison between said first correlation sequence and the first accumulative energy scaled by a first predetermined threshold; and a sixth means for asserting said second signal according to another comparison between said second correlation sequence and the second accumulative energy scaled by a second predetermined threshold; and a decision making unit for identifying said newly arrived network packet as an OFDM modulated packet if said first and said second signals are both asserted.