Title :
Enhanced Channel Equalizers for Adaptive Zero-Guard-Interval CO-OFDM Systems
Author :
Wei Wang ; Qunbi Zhuge ; Yuliang Gao ; Meng Qiu ; Chagnon, Mathieu ; Sowailem, Mohammed Y. ; Fangyuan Zhang ; Plant, David V.
Author_Institution :
Dept. of Electr. & Comput. Eng., McGill Univ., Montreal, QC, Canada
Abstract :
We propose the design and implementation of frequency domain block least mean square and block recursive least square equalizers for adaptive zero-guard-interval (ZGI) coherent optical (CO) orthogonal frequency division multiplexing (OFDM) systems. We experimentally demonstrate the improvements in fiber nonlinear tolerance and channel estimation accuracy over conventional training symbol (TS)-based equalizers and data aided zero-forcing (ZF) equalizers, in single channel 112-Gb/s quadrature phase shift keying (QPSK), and 250-Gb/s 16 quadrature amplitude modulation (QAM) ZGI CO-OFDM systems. The transmission distance is increased by 20% and 7% for QPSK, and 53% and 35% for 16-QAM systems, compared with the TS-based and decision aided ZF adaptive equalizers, respectively. In addition, simulation results demonstrate the improved temporal tracking ability of the proposed algorithms over the previous ZF equalizer.
Keywords :
OFDM modulation; channel estimation; equalisers; least mean squares methods; nonlinear optics; optical communication equipment; optical design techniques; optical fibre communication; quadrature amplitude modulation; quadrature phase shift keying; QAM; QPSK; ZGI coherent optical OFDM; adaptive zero-guard-interval CO-OFDM systems; bit rate 250 Gbit/s; block recursive least square equalizers; channel estimation accuracy; data aided zero-forcing equalizers; enhanced channel equalizers; fiber nonlinear tolerance; frequency domain block least mean square equalizers; quadrature amplitude modulation; quadrature phase shift keying; temporal tracking ability; training symbol-based equalizers; transmission distance; Adaptive equalizers; Bit error rate; Frequency-domain analysis; OFDM; Optimized production technology; Phase shift keying; Adaptive equalizer; coherent detection; orthogonal frequency division multiplexing; training symbol;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2015.2438256
