Joint Iterative Carrier Synchronization and Signal Detection Employing Expectation Maximization

Author

Zibar, D. ; Hecker de Carvalho, Luis Henrique ; Estaran, Jose ; Silva, Enrico ; Franciscangelis, Carolina ; Ribeiro, V. ; Borkowski, Robert ; Winther, Ole ; Schmidt, Mikkel N. ; Oliveira, Juliano ; Tafur Monroy, Idelfonso

Author_Institution

Dept. of Photonics Eng., Tech. Univ. of Denmark, Lyngby, Denmark

Volume

32

Issue

8

fYear

2014

fDate

15-Apr-14

Firstpage

1608

Lastpage

1615

Abstract

In this paper, joint estimation of carrier frequency, phase, signal means and noise variance, in a maximum likelihood sense, is performed iteratively by employing expectation maximization. The parameter estimation is soft decision driven and allows joint carrier synchronization and data detection. The algorithm is tested in a mixed line rate optical transmission scenario employing dual polarization 448 Gb/s 16-QAM signal surrounded by eight on-off keying channels in a 50 GHz grid. It is shown that joint carrier synchronization and data detection are more robust towards optical transmitter impairments and nonlinear phase noise, compared to digital phase-locked loop (PLL) followed by hard decisions. Additionally, soft decision driven joint carrier synchronization and detection offers an improvement of 0.5 dB in terms of input power compared to hard decision digital PLL based carrier synchronization and demodulation.

Keywords

amplitude shift keying; demodulation; expectation-maximisation algorithm; optical computing; optical modulation; optical phase locked loops; optical signal detection; optical transmitters; parameter estimation; phase noise; quadrature amplitude modulation; synchronisation; 16-QAM signal; bit rate 448 Gbit/s; carrier frequency; carrier phase; data detection; demodulation; digital phase-locked loop; dual polarization; expectation maximization; frequency 50 GHz; gain 0.5 dB; hard decision digital PLL based carrier synchronization; joint estimation; joint iterative carrier synchronization; mixed line rate optical transmission scenario; noise variance; nonlinear phase noise; on-off keying channels; optical transmitter impairments; parameter estimation; signal detection; signal means; soft decision; Equations; Joints; Mathematical model; Maximum likelihood estimation; Noise; Parameter estimation; Synchronization; Advanced modulation formats; coherent detection; digital signal processing (DSP); expectation maximization (EM); maximum likelihood;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/JLT.2014.2308636

Filename

6748875