Efficient FFT/IFFT Implementation Technique for OFDM on FPGA

Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier modulation technique which divides the available spectrum into many carriers. OFDM uses the spectrum efficiently compared to FDMA by spacing the channels much closer together and making all carriers orthogonal to one another, to prevent interference between the closely spaced carriers. The main advantage of OFDM is their robustness to channel fading in wireless environment. The principles of OFDM modulation have been around since 1960s. However, recently the attention toward OFDM has grown dramatically in the field of wireless and wired communication systems. In parallel, Field Programmable Gate Array (FPGA) is also emerging as a fundamental paradigm in the implementation of these standards. This is due to their increased capabilities (speed and resources). The objective of this project is to design and implement OFDM transmitter and receiver on FPGA hardware. This project concentrates on developing Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT), in an efficient way. The work also includes design of a mapping module (Modulator), serial to parallel and parallel to serial converter module. The design uses 64-point FFT and IFFT for the processing module, which indicate that the processing block contain 64 inputs data. In this work, a pure VHDL design, integrated with some intellectual property (IP) blocks, is employed to implement an OFDM transmitter and receiver. The proposed design is map and test on Xilinx Spartan 3E FPGA and for simulation, synthesis and implementation XILINX ISE 13.2 software is used.