Memory efficient DIT-based SDF IFFT for OFDM systems

Abstract

This paper presents a new memory reduction method of IFFT for OFDM systems, based on a mapping of three IFFT input signals which consist of modulated data, pilot and null signals. The proposed method focuses on reducing the memory size in the bitreversal part which requires the largest number of memory cells in IFFT architectures. To reduce the memory size, we propose a decimation-in-time (DIT) twiddle factor shifting algorithm to remove the multiplications in the first two stages. It is shown that the proposed method achieves a memory reduction of about 30% compared to previous methods.