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Design and Comparison of the Pipelined IFFT/FFT modules for IEEE 802.11a OFDM System  

이창훈 (동아대학교 전자공학과)
김주현 (동아대학교 전자공학과)
강봉순 (동아대학교 전기전자컴퓨터공학부)
Publication Information
Journal of the Korea Institute of Information and Communication Engineering / v.8, no.3, 2004 , pp. 570-576 More about this Journal
Abstract
In this paper, we design the IFFT/FFT (Inverse fast Fourier Transform/Fast Fourier Transform) modules for IEEE 802.11a-1999, which is a standard of the High-speed Wireless LAN using the OFDM (Orthogonal Frequency Division Multiplexing). The designed IFFT/FFT is the 64-point FFT to be compatible with IEEE 802.11a and the pipelined architecture which needs neither serial-to-parallel nor parallel-to-serial converter. We compare four types of IFFT/FFT modules for the hardware complexity and operation : R22SDF (Radix-2 Single-path Delay feedback), the R2SDF (Radix-2 Single-path Delay feedback), R2SDF (Radix-4 Single-path Delay Feedback), and R4SDC (Radix-4 Single-path Delay Commutator). In order to minimize the error, we design the IFFT/FFT module to operate with additional decimal parts after butterfly operation. In case of the R22SDF, the IFFT/FFT module has 44,747 gate counts excluding RAMs and the minimized error rate as compared with other types. And we know that the R22SDF has a small hardware structure as compared with other types.
Keywords
IEEE 802.11a; OFDM; IFFT/FFT; Pipelined FFT;
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