A novel method for converting the N-point complex sequence of frequency-domain to 2N-point real sequence of time-domain with N-point IFFT computation

In OFDM/DMT systems, the spectrum of N-point baseband signal contains a total of 2N frequency points ranging from -F_N to F_N. Owing to the periodic continuation of FFT, the range of frequencies from -F_N to 0 and from F_N to 2F_N are equivalent, and 2N-point IFFT computation is essential for getting time-domain real sequence signal. In this paper, we present a novel method achieving the same effect which only needs N-point IFFT computation based on the theory of DFT/IDFT. Compared to the traditional method in need of 2N point IFFT computation, our approach significantly reduces power consumption and silicon area requirement, which has considerable practical significance.