VHDL Design of OFDM Transreceiver Chip using Variable FFT

Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier transmission technique that divides the available spectrum into multiple carriers in which each one is being modulated by a low rate data stream. OFDM is similar to FDMA in that the multiple user access is achieved by subdividing the available bandwidth into multiple channels band, which is then allocated to users. So, OFDM uses the spectrum much more efficiently by spacing the channels much closer together. It is possible by making all the carriers orthogonal to each another, preventing interference between the closely spaced carriers. The research is relating to the design and synthesis of variable input FFT processor which is designed to meet the requirements of OFDM & OFDMA system. The FFT and IFFT pairs are used to modulate and demodulate the data constellation on the subcarriers in OFDM and OFDMA. The research presents a high level implementation of a high performance FFT for OFDM Demodulator. The work is carried out on Xilinx 14.2 software and functional checked in Modelsim 10.1b software. The language used for the design in VHDL. KeywordsOrthogonal Frequency Division Multiplexing (OFDM), Fast Fourier Transform (FFT), Inverse Fast Fourier Transform (IFFT), Very Large Scale of Integration (VLSI), Hardware Description language (HDL)