High speed eight-parallel mixed-radix FFT Processor for OFDM systems

This paper presents a novel eight-parallel 128/256-point mixed-radix multi-path delay commutator (MRMDC) FFT processor for orthogonal frequency-division multiplexing (OFDM) systems. The proposed FFT architecture can provide a higher throughput rate and low hardware complexity by using an eight-parallel data-path scheme, a multi-path delay commutator structure and an efficient scheduling scheme of complex multiplications. Using the modified radix-4 butterfly unit which can perform one radix-4 butterfly or two radix-2 butterflies, the proposed FFT processor can provide 128 and 256-point FFT computations. The proposed FFT processor has been designed and implemented with the 90nm CMOS technology. The proposed eight-parallel FFT processor can provide a throughput rate of up to 27.5Gsample/s at 430MHz.