Real-Time FFT Computation Using GPGPU for OFDM-Based Systems

Abstract

In optical and wireless communications systems, the goal is to reach 10 Gbps or above data rates. In order to support such extremely high data rates, the physical layer generally uses orthogonal frequency division multiplexing (OFDM) modulation. Unlike serial transmission of symbols, the OFDM modulation transmits data with many parallel sub-carriers, which help to provide high bandwidth. Field programmable gate arrays (FPGAs) and digital signal processors (DSPs) are usually employed to process OFDM blocks in real time. However, FPGAs and DSPs are not cost effective, and they are difficult to adapt to new standards. One of the most computationally intensive functions in OFDM systems is the fast Fourier transform (FFT) computation process. This paper aims to accelerate the FFT process to achieve high communication throughput in real time. Two parallel approaches are implemented for two different NVIDIA graphics processing unit (GPU) architectures. To obtain the best performance values, several optimizations are implemented. Our general purpose graphics processing unit (GPGPU)-based FFT computation achieves up to 24 Gbps throughput in real time.