Patent ID: 8325835

Claim:
A Non-Continuous Orthogonal Frequency Division Multiplexing (NC-OFDM) system, comprising: a sensing unit to determine whether to use at least one frequency band; a band control unit to disable a subcarrier with respect to a frequency band in use as a result of the determination; a pruning determination unit to determine whether a number of points where the subcarrier is disabled is greater than a threshold value; a pruning retrieval unit to retrieve a pruning path generated by the disabling of the subcarrier, when the number of points is greater than the threshold value; and a Fourier transform unit to perform a Fast Fourier transform (FFT) or Inverse FFT (IFFT) by applying the pruning path to the subcarrier; wherein, when the FFT is performed by the Fourier transform unit, the pruning retrieval unit simultaneously performs the FFT and retrieves the pruning path in a backward path.