Vlsi framework for efficient fft ifft algorithms

Abstract

The research attention towards high speed wireless data communication, broadband access and information sharing has been dramatically increased in recent years. The wireless communication standards have been consistently upgraded in order to improve the data rate and reliability. At the same time, the integrated chip design engineers face a continuous challenging task to manage with the limited availability of radio frequency spectrum, channel problems such as fading and multipath and meeting the demands for the wireless communication standards at a low hardware cost. Orthogonal Frequency Division Multiplexing (OFDM), is a spectrally efficient digital modulation technique, which is insusceptible to multipath fading, narrow band issues, Inter Carrier Interference (ICI) and Inter Symbol Interference (ISI), makes it as a promising component for communication systems in recent trend. Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO OFDM) has wide range of applications in the field of wireless communications such as IEEE 802.11, IEEE 802.15, IEEE 802.16, IEEE 802.20, Worldwide Interoperability for Microwave Access (WiMAX) and 3 rd Generation Partnership Project (3GPP) Long Term Evolution (LTE). The Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) are the essential components in an OFDM transceiver. The FFT and IFFT algorithms efficiently implement the complex computations involved in Discrete Fourier Transform (DFT) and Inverse Discrete Fourier Transform (IDFT) operations respectively. The present-day advancements in communication technologies such as optical OFDM, Flash OFDM, massive MIMO in next generation telecommunication systems, cooperative MIMO and multi-user MIMO require an efficient FFT/IFFT computation unit to meet the specifications of the standards. A real time implementation of high performance FFT/IFFT computations that occupies less area and operates in minimum power consumption is highly indispensible in designing an MIMO OFDM integrated chip. The performance evaluation of FFT/IFFT computation necessitates the Field Programmable Gate Array (FPGA) and Application Specific Integrated Circuits (ASIC) implementation solution. newline