Design of a new IFFT/FFT for IEEE 802.11a WLAN based on the statistics distribution of the input data

Abstract

This paper presents a new design method of IFFT/FFT minimizing the quantization errors based on the statistical analysis of the input data distribution in 802.11a WLAN. The proposed algorithm decides the twiddle coefficients by applying the statistically calculated spreading coefficient from the data distributions which is a ratio of the data amplitude of the ancestor and the present stage. The data was leaned toward to one at each input stage, and is expanded by a new twiddle coefficient. We implemented this algorithm with radix-22 SDF(single-path delay feedback) architecture [1]. Both IFFT and FFT processor can share the circuit modules by the symmetric nature of them. We designed a base band processor including IFFT for TX and FFT for RX with I/O of 10 bits on a platform. It showed that the maximum quantization error is 0.0021. This is same as that the proposed algorithm improved the quantization errors with the linear bit extension by 3 bits. It yields reducing quantization error SdB and smaller hardware size. © Springer-Verlag Berlin Heidelberg 2004.