Implementation of DCT based OFDM system

The conventional OFDM system employs the IFFT-FFT structure to impart the orthogonolity feature. However, due to complex nature of FFT, implementation size is large enough. The orthogonolity can also be provided if IDCT-DCT structure is used in place of FFT. This will reduce the implementation area and will also increase the computation speed as only real calculations are required. In this paper we present the implementation of DCT based OFDM system. The DCT structure prevalent in H.264 standard is taken into reference as it has faster operation as compared to conventional DCT structure. The implementation of DCT-IDCT structure was done on ALTERA CYCLONE -II FPGA. The results show that the speed of calculation of orthogonal components is increased three folds while the implementation size reduces to half as compared to FFT based design.