Journal of Shanghai University(Natural Science Edition) ›› 2016, Vol. 22 ›› Issue (4): 398-407.doi: 10.3969/j.issn.1007-2861.2014.05.018

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Design and implementation of FFT/IFFT processors with word-length optimization for OOFDM-PON system

WANG Kai, WU Qi, LI Jiaqi, XUE Ziwei, ZHANG Junjie   

  1. School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China
  • Received:2014-11-26 Online:2016-08-30 Published:2016-08-30

Abstract:

High-speed parallel fast Fourier transform/inverse fast Fourier transform (FFT/IFFT) module has become one of the most significant obstacle to practically developing realtime high-speed optic orthogonal frequency division multiplexing (OOFDM) system based on field programmable gate array (FPGA) platform due to its high complexity. This paper builds a simulation platform for OOFDM transceivers and realizes joint optimization of the IFFT and FFT module to reduce logic resource usage. The algorithm shortens word-length boundaries to reduce the time for searching optimized word-length and builds a mapping
table of the optimal word-lengths. Error between simulation results and verification results on an offline platform is within 0.5 dB indicating correctness of the proposed optimization algorithm. In addition, the FFT module based on the mapping table saves about 37.2% resource compared to the Spiral design.

Key words:  fast Fourier transform/inverse fast Fourier transform (FFT/IFFT) ,  inverse error vector magnitude (IEVM),  wordlength optimization , optical orthogonal frequency division multiplexing-passive optical network(OOFDM-PON)