Patent ID: 7978776

Claim:
An orthogonal frequency division multiplexing (OFDM) system for transmitting a modulated subcarrier signal from a transmitting end, transforming a frequency domain signal into a time domain signal via an inverse fast Fourier transform, inserting a guard interval between two time domain signals and transforming a time domain signal from parallel data into serial data to establish the modulated subcarrier signal, transmitting the modulated subcarrier signal from the transmitter via a wireless channel to a receiver, the receiver transforming serial data of the modulated subcarrier signal received into parallel data and removing the guard interval, utilizing a fast Fourier transform process to transform the time domain signal into a frequency domain signal to provide a received signal, using an equalizer to obtain an original received signal, and restore an original two digits information output via signal inverse correspondence, characterized in that: error detection is performed on the received signal obtained from the fast Fourier transform process to detect whether the received modulated subcarrier signal has any errors, and a channel estimator selectively executes to obtain a frequency response of the channel responsive to the error detection.