Long point FFT design for frequency domain equalization of few-mode fiber communication

HUANG Zhanhua; ZHAO Yulu; LI Guifang; WANG Yunli

doi:10.7510/jgjs.issn.1001-3806.2016.02.003

To reduce the circuit's power and size of frequency domain equalization (FDE) system, and meet the requirements of FDE in long-distance few-mode fiber communication, the circuit for fast Fourier transformation (FFT), the key of FDE, was studied. The long point FFT operation was converted to short FFT by means of 2-D decomposition algorithm, and the hardware complexity was reduced. High-speed butterfly core based on field-programmable gate array(FPGA) was designed to implement 2-D R22SDF structure of 16384 point FFT, improve the resource utilization of memory and reduce the usage of complex multipliers. Through theoretical analysis and experiments, resource consumption information of the circuit under different clock frequencies was collected. The result show that the designed FFT can satisfy the optimization requirement of FDE circuit structure in few-mode fiber communication and realize real-time processing of 200MHz data speed in FDE.

Long point FFT design for frequency domain equalization of few-mode fiber communication

1. Key Laboratory of Opto-electronics Information Technology of Ministry of Education, School of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China

Received Date: 2015-01-30

Accepted Date: 2015-04-01

Available Online: 2016-03-25

Abstract: To reduce the circuit's power and size of frequency domain equalization (FDE) system, and meet the requirements of FDE in long-distance few-mode fiber communication, the circuit for fast Fourier transformation (FFT), the key of FDE, was studied. The long point FFT operation was converted to short FFT by means of 2-D decomposition algorithm, and the hardware complexity was reduced. High-speed butterfly core based on field-programmable gate array(FPGA) was designed to implement 2-D R22SDF structure of 16384 point FFT, improve the resource utilization of memory and reduce the usage of complex multipliers. Through theoretical analysis and experiments, resource consumption information of the circuit under different clock frequencies was collected. The result show that the designed FFT can satisfy the optimization requirement of FDE circuit structure in few-mode fiber communication and realize real-time processing of 200MHz data speed in FDE.

HTML

Reference (16)

[1]	GRNER-NIELSEN L, SUN Y I, NICHOLSON J W, et al. Few mode transmission fiber with low DGD, low mode coupling, and low loss[J]. Journal of Lightwave Technology, 2012, 30(23):3693-3698.
[2]	FERREIRA F, FONSECA D, LOBATO A, et al. Reach improvement of mode division multiplexed systems using fiber splices[J]. IEEE Photonics Technology Letters, 2013, 25(12):1091-1094.
[3]	CAO X. Optimization of dispersion compensation in optical fiber communication systems[J]. Laser Technology, 2014, 38(1):101-104(in Chinese).
[4]	RYF R, RANDEL S, GNAUCK A H, et al. Mode-division multiplexing over 96km of few-mode fiber using coherent 66 MIMO processing[J]. Journal of Lightwave Technology, 2012, 30(4):521-531.
[5]	FARUK M S, KIKUCHI K. Adaptive frequency-domain equalization in digital coherent optical receivers[J]. Optics Express, 2011, 19(13):12789-12798.
[6]	BAI N. Mode-division multiplexed transmission in few-mode fibers[D]. Orlando,Florida,USA:University of Central Florida Orlando, 2013:9-20.
[7]	BAI N, IP E, LI M J, et al. Long-distance mode-division multiplexed transmission using normalized adaptive frequency domain equalization[C]//IEEE Photonics Society Summer Topical Meeting Series. New York, USA:IEEE, 2013:135-136.
[8]	BAI N, LI G F. Adaptive frequency-domain equalization for mode-division multiplexed transmission[J]. IEEE Photonics Technology Letters, 2012, 24(21):1918-1921.
[9]	BAI N, IP E, HUANG Y K, et al. Mode-division multiplexed transmission with inline few-mode fiber amplifier[J]. Optics Express, 2012, 20(3):2668-2680.
[10]	YAMAN F, BAI N, ZHU B Y, et al. Long distance transmission in few-mode fibers[J]. Optics Express, 2010, 18(12):13250-13257.
[11]	HE H, KE X Zh, WANG W. Particle filtering based semi-blind estimation for atmospheric laser OFDM time-varying channel[J]. Laser Technology, 2011, 35(6):738-741(in Chinese).
[12]	LI S M, CHEN Y, ZENG X Y. FFT/IFFT processor for MIMO-OFDM[J]. Computer Engineering, 2012, 38(2):248-249(in Chinese).
[13]	JIANG X, TANG G, WU B. Design of configurable high precision FFT/IFFT Processor[J]. Micro Electronics and Computer, 2010(7):44-48(in Chinese).
[14]	WANG X Y. Implementation of wavelet denoising algorithm based on FPGA[J]. Laser Technology, 2013, 37(6):786-790(in Chinese).
[15]	ZHANG L J. Research on FPGA parallel implementation of two-dimension long FFT algorithm[J]. Radio Communications Technology, 2013, 39(3):86-88(in Chinese).
[16]	LI W, SUN J P, WANG J, et al. Implementation of 32k points ultrahigh speed FFT processor based on FPGA devices[J]. Journal of Beijing University of Aeronautics and Astronautics, 2008, 33(12):1440-1443(in Chinese).

Long point FFT design for frequency domain equalization of few-mode fiber communication

Abstract

References

Proportional views

通讯作者: 陈斌, bchen63@163.com

Proportional views