Open AccessA complex-weighted, decision-aided, maximum-likelihood carrier phase and frequency-offset estimation algorithm for coherent optical detection
Author(s) -
Adaickalavan Meiyappan,
Pooi Yuen Kam,
Hoon Kim
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.020102
Subject(s) - frequency offset , phasor , phase shift keying , continuous phase modulation , carrier frequency offset , algorithm , carrier recovery , symbol rate , estimator , phase noise , amplitude and phase shift keying , computer science , keying , phase modulation , optics , bit error rate , demodulation , mathematics , telecommunications , physics , orthogonal frequency division multiplexing , statistics , channel (broadcasting) , decoding methods , power (physics) , electric power system , quantum mechanics
We present a symbol-by-symbol coherent optical receiver, which employs a novel, complex-weighted, decision-aided, maximum-likelihood (CW-DA-ML) carrier phase and frequency offset estimator. The CW-DA-ML carrier estimator uses a CW transversal filter to generate a carrier reference phasor, and the filter weights are automatically adapted on-line by linear regression on the observed signals. A complete modulo-R reduced frequency offset estimation (FOE) range of ± R/2 is achieved, independent of modulation format, where R is the symbol rate. Carrier phase and frequency tracking is achieved rapidly. The acquisition speed of frequency offset in quaternary phase-shift keying (4-PSK) signals is more than 5 times faster than that of differential FOE. A constant penalty of approximately 1 dB at bit-error rate of 10(-4) is demonstrated for all frequency offsets in 4-PSK signals with laser-linewidth-symbol-duration product of 8 × 10(-5).