| 1. |
- Johannisson, Pontus, 1976, et al.
(författare)
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Convergence Comparison of CMA and ICA for Blind Polarization Demultiplexing of QPSK and 16-QAM Signals
- 2010
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Ingår i: Proceedings of European Conference on Optical Communication, ECOC 2010, Turin, Italy, September 19-23, 2010. - 9781424485352
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Konferensbidrag (refereegranskat)abstract
- Two algorithms for blind polarization demultiplexing, based on the constant modulus criterion and independent component analysis, are compared. It is found that the latter converges significantly faster to within a given SNR penalty tolerance.
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| 2. |
- Johannisson, Pontus, 1976, et al.
(författare)
-
Convergence Comparison of the CMA and ICA for Blind Polarization Demultiplexing
- 2011
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Ingår i: Journal of Optical Communications and Networking. - 1943-0620 .- 1943-0639. ; 3:6, s. 493-501
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Tidskriftsartikel (refereegranskat)abstract
- An algorithm based on independent component analysis for blind polarization demultiplexing in a coherent transmission system is presented. A comparison with the constant modulus algorithm in terms of the convergence properties is performed, and it is found that the suggested algorithm has a significantly faster convergence rate and does not have any singularity problems. We also demonstrate that the algorithm convergence is strongly dependent on the choice of starting condition and show how this can be exploited to increase the convergence rate.
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| 3. |
- Karout, Johnny, 1985, et al.
(författare)
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CMA Misconvergence in Coherent Optical Communication for Signals Generated from a Single PRBS
- 2011
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Ingår i: Wireless & optical communications conference, New Jersey, 15-16 April 2011. - 9781457704543
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Konferensbidrag (refereegranskat)abstract
- In the experimental study of modulators for coherent optical communications, it is common to generate multilevel signals using a single pseudo-random binary sequence. This simple experimental realization leads to symbol correlation. When modulators are studied in combination with adaptive receiver algorithms that rely on independent data, misconvergence may result. In this contribution, we investigate the impact of such correlation on a standard blind equalization method and provide guidelines to avoid misconvergence. Our results indicate that care needs to be taken when using a single PRBS sequence and that decorrelation delays must be chosen appropriately. We present simulation and theoretical results for 16-QAM, and show how our results can be applied to other multi-level constellations.
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| 4. |
- Peng, Fangrong, 1986, et al.
(författare)
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Operational Regime of Symbol-by-Symbol Phase Noise Estimation for POLMUX 16-QAM
- 2010
-
Ingår i: Proceedings of European Conference on Optical Communication, ECOC, Turin, Italy, September 19-23, 2010. - 9781424485352
-
Konferensbidrag (refereegranskat)abstract
- A symbol-by-symbol phase noise estimation algorithm for polarization-multiplexed 16-QAM is evaluated. We found that it can cope with laser linewidths of up to 2.2 MHz in high SNR regimes, at 112 Gbit/s.
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| 5. |
- Tan, Ahmet Serdar, 1982, et al.
(författare)
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An ML-based Detector for Optical Communication in the Presence of Nonlinear Phase Noise
- 2011
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Ingår i: IEEE International Conference on Communications. - : IEEE. - 1550-3607. - 9781612842332 ; , s. Art. no. 5962741-
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Konferensbidrag (refereegranskat)abstract
- We present a closed-form maximum likelihood-based data detection algorithm for long-haul optical channels with dominant nonlinear phase noise induced by self-phase modulation. The closed-form detector is evaluated in terms of symbol error rate as a function of input power, and compared with other sub-optimal detectors as well as a non-parametric detector. We show that the performance of the detector deteriorates for high input power levels, resulting in an optimal operation region. We also provide insights into the behavior of the detector in the highly nonlinear regime.
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| 6. |
- Tan, Ahmet Serdar, 1982, et al.
(författare)
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Modified Cramer-Rao Bound for Clock Recovery in the Presence of Self-Phase Modulation
- 2012
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 30:16, s. 2556-2562
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the effect of nonlinear self-phase modulation (SPM) on clock recovery in long-haul coherent optical communication systems with low to moderate baud rates. We consider dual-polarization, multilevel quadrature amplitude modulation, and evaluate conventional timing estimators as well as a modified Cramer-Rao bound. As the latter is hard to compute in the presence of nonlinear channel impairments, we derive an approximate closed-form expression. Contrary to linear channel impairments, the nonlinear impairments can degrade the performance for higher input powers. In addition, the bounds exhibit oscillatory behavior due to the oscillations in the signal spectrum in the presence of SPM.
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| 7. |
- Tan, Ahmet Serdar, 1982, et al.
(författare)
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The Impact of Self-Phase Modulation on Digital Clock Recovery in Coherent Optical Communication
- 2010
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Ingår i: Proceedings of European Conference on Optical Communication, ECOC 2010, Turin, Italy, September 19-23, 2010. - 9781424485352
-
Konferensbidrag (refereegranskat)abstract
- The impact of self-phase modulation on the estimation error variance of digital clock recovery schemes for coherent 16-QAM dual-polarization systems is investigated. The error variance increases severely compared to the linear case and the theoretical bounds.
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