An Area and Power-Efficient Serial Commutator FFT with Recursive LUT Multiplier

This paper presents an area and power-efficient architecture for serial commutator real-valued fast Fourier transform (FFT) using recursive look-up table (LUT). FFT computation consists of butterfly operations and twiddles factor multiplications. The area and power performance of FFT architectures are mainly limited by the multipliers. To address this, a new multiplier is proposed which stores the partial products in LUT. Moreover, by adding the shifted version of twiddle coefficients, the stored partial products gain symmetry, and thus the size of LUT can be reduced to half. Further symmetry is achieved by adding another shifted version of twiddle coefficients and so on. This makes the proposed LUT multiplier recursive in nature. A new data management scheme is suggested for the proposed architecture. To validate the proposed architecture, application-specific integrated circuit (ASIC) synthesis and field-programmable gate array (FPGA) implementation are carried out for different symmetry factor. For instance, the proposed architecture for 1024-point with symmetry factor of two achieves 39.11% less area, 42.29% less power, 33.27% less sliced LUT (SLUT) and 29.18% less flip-flop (FF) as compared to the best existing design.