Coefficient Ordering Based Pipelined FFT/IFFT with Minimum Switching Activity for Low Power WiMAX Communication System

In this paper, we present a modified coefficient ordering based pipelined 256-point FFT/IFFT processor with minimum switching activity for IEEE 802.16-2004 (or WiMAX) system. The fixed radix-4 and single-path pipelined architecture is used in this FFT design. The pipelined architecture provides higher throughput rate comparing with the iterative architecture. We have shown that the low power issue is addressed by minimizing the switching activity using minimum Hamming distance transition. The switching activity of twiddle computation is thus reduced from 181 to 71, i.e. 61% reduction. We have implemented the VLSI design of the OFDM transmitter with 16-bit word length. The signal to quantization noise ratio is improved to 120 dB