收稿日期: 2014-11-26
网络出版日期: 2016-08-30
基金资助
国家自然科学基金资助项目(61132004, 61275073, 61420106011); 上海市科委重点资助项目(13JC1402600, 14511100100, 15511105400, 15530500600)
Design and implementation of FFT/IFFT processors with word-length optimization for OOFDM-PON system
Received date: 2014-11-26
Online published: 2016-08-30
在基于现场可编程门阵列(field programmable gate array, FPGA)平台实现的实时光正交频分复用无源光网(optical orthogonal frequency division multiplexing-passive optical network, OOFDM-PON)系统中, 由于实时全并行快速傅里叶变换/快速傅里叶反变换(fast Fourier transform/inverse fast Fourier transform, FFT/IFFT)模块计算复杂度高, 成为实时OOFDM-PON系统设计的主要瓶颈之一. 构建OOFDM-PON发送与接收仿真平台, 通过联合优化OOFDM-PON发送端的IFFT与接收端FFT蝶形运算的旋转因子和输出字长来降低模块的系统逻辑资源占用率. 采用基于缩短字长界限范围的方法来减少最优化字长的搜索时间, 同时构建了实时OOFDM-PON系统的基于DIF-2的64点IFFT/FFT的字长优化映射表. 该映射表在离线OOFDM-PON平台上的验证结果与仿真结果之间的误差控制在0.5 dB,验证了该优化算法的正确性. 与Spiral设计方案相比, 该设计的基于上述映射表的FFT模块可以节约大约37.2%的逻辑资源.
关键词： 反向误差向量幅度; 快速傅里叶变换/快速傅里叶反变换; 字长优化; 光正交频分复用无源光网
王凯, 吴琦, 李家齐, 薛子威, 张俊杰 . OOFDM-PON系统的FFT/IFFT字长联合优化设计与实现[J]. 上海大学学报(自然科学版), 2016 , 22(4) : 398 -407 . DOI: 10.3969/j.issn.1007-2861.2014.05.018
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.
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