Patent ID: 8155254

Claim:
A method for determining an optimal position of a Fast Fourier Transform (FFT) window at a receiver of an orthogonal frequency division multiplex (OFDM) wireless communication system under the condition that the channel impulse response (CIR) length is larger than the cyclic prefix (CP) length, comprising: receiving a plurality of adjacent OFDM symbols in time where the received signal is modeled in a frequency domain; estimating a power of a desired signal collected inside the FFT window for a currently processed OFDM symbol from an arbitrary channel path based on different relative positions between a beginning of the FFT window and a time delay of arbitrary channel path; estimating a power of the noise collected inside the FFT window for the currently processed OFDM symbol from the arbitrary channel path based on different relative positions between the beginning of the FFT window and the time delay of arbitrary channel path; computing a theoretical carrier-to-noise (C/N) ratio at the receiver as a function of the FFT window position based on the estimated power of desired signal and the estimated power of the noise; and determining the optimal position of the FFT window in an effort to optimize the theoretical C/N ratio value at the receiver.