Modified Cooley-Tukey algorithm for implementation of integrated serial FFT/IFFT processor in half-duplex OFDM systems

Orthogonal Frequency Division Multiplexing (OFDM) is one of the most spectrally efficient methods so far, which helps to achieve high data rates and also mitigates the severe problem of the multipath propagation and Inter Symbol Interference. Many IEEE 802.11 standards have adopted OFDM in their implementations for wireless systems. The heart of the OFDM is the digital implementation of Discrete Fourier Transform (DFT). DFT is efficiently implemented by FFT and IFFT algorithms. Radix-2 FFT Cooley-Tukey algorithms are quite popular for FFT and IFFT [1] implementations. The objective of this paper is to propose a modified Cooley-Tukey Radix-2 Single-path delay feedback algorithm which is capable of computation of both FFT and IFFT for serial inputs with the help of same hardware rather than separate for each. The combined FFT/IFFT processor can find its applications in half-duplex OFDM-based communication systems. Due to the efficiency and simplicity of the hardware, this implementation is attractive for low-cost applications.