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

Volume

27

Issue

16

fYear

2015

fDate

Aug.15, 15 2015

Firstpage

1721

Lastpage

1724

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;

fLanguage

English

Journal_Title

Photonics Technology Letters, IEEE

Publisher

ieee

ISSN

1041-1135

Type

jour

DOI

10.1109/LPT.2015.2438256

Filename

7114221