FPGA Based Variable - Point FFT Processor
An efficient variable length FFT processor is required for the downlink module of Orthogonal Frequency Division Multiple Access (OFDMA) system. This system is used in the mobility mode of the IEEE 802.16 Wireless MAN standard, commonly referred as WiMAX .In OFDMA system the carrier space is constant across different channel bandwidths.FFT is required to keep the carrier spacing constant across different channel bandwidths. In this paper the variable input FFT processor is designed to meet the requirements of OFDMA system. This design considers different FFT lengths. For this the authors use the 2D Fourier Transform algorithm, VHDL language to present the design in detail, ModelSim for the simulation and verify on the Spartan 3E FPGA.