FPGA Implementation of FFT Algorithm for OFDM Based IEEE 802.16d (Fixed WiMAX) Communications

⎯The IEEE 802.16d communication standard uses orthogonal frequency division multiplexing (OFDM). In the widely used OFDM systems, the fast Fourier transform (FFT) and inverse fast Fourier transform pairs are used to modulate and demodulate the data constellation on the sub-carriers. In this paper, a high level implementation of a high performance FFT for OFDM modulator and demodulator is presented. The design has been coded in Verilog and targeted into Xilinx Spartan3 field programmable gate arrays. Radix-2 algorithm is proposed and used for the OFDM communication system. The design of the FFT is implemented and applied to fixed WiMAX— IEEE 802.16d communication standard. The results are tabulated and the hardware parameters are compared. The proposed architecture is least in number of multipliers used and the memory size, and second to the least in number of adders used. Index Terms⎯Fast Fourier transform, orthogonal frequency division multiplexing, radix conversion, Verilog. d oi: 10.3969/j.issn.1674-862X.2010.03.001