Low latency IFFT design for OFDM systems supporting full-duplex FDD

In this paper, we describe a low latency Inverse Fast Fourier Transform (IFFT) design method for OFDM systems supporting full-duplex Frequency Division Duplex (FDD). To support full-duplex FDD OFDM systems means that transmission and reception are simultaneously performed. In order to reduce the IFFT output latency, we propose the reordering scheme of IFFT input data. By using the reordered IFFT input data, both the output latency and the memory size in the first stage of IFFT are significantly reduced. In the OFDM systems, input data of the IFFT corresponding to guard band are assigned as null. Low latency IFFT design method is proposed based on the fact that there are many null as an input data of IFFT. The proposed method focuses on reducing the memory size in the first stage of single-path delay feedback (SDF) IFFT architectures since the first stage occupies about 50% of the overall memory. To verify the efficiency of the proposed method, 2048-point IFFT with radix-2 SDF architecture is used and reduced about 41% compared with conventional architecture.