Efficient digital IF architecture for wideband OFDM systems based on CIC filter

Cascaded integrator-comb (CIC) filter plays a vital role in sampling rate conversion of digital intermediate frequency (IF) architecture. Due to no multipliers and limited storage, CIC filter can economically complete interpolation and decimation, which has a quite important significance especially for wideband communication systems with high data rate. This paper presents an efficient digital IF architecture for wideband orthogonal frequency division multiplexing (OFDM) systems on the basis of CIC filter. By selecting the suitable size of inverse fast Fourier transform (IFFT) versus the number of data sub-carriers and exploiting frequency-domain channel estimation, the passband droop caused by CIC filter can be effectively reduced. We provide analyses and simulations of the proposed CIC filter-based digital IF architecture for wideband OFDM systems. The results show that an excellent performance can be obtained even if in the case of multi-path interference.