Memory efficient DIT-based SDF IFFT for OFDM systems

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 bit-reversal 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.