Principles for Electronic Equalization of Polarization-Mode Dispersion

Abstract. Turbo equalization is a widely known method to cope with low signal to noise ratio (SNR) channels corrupted by linear intersymbol interference (ISI) Hagenauer et al., 1997). Recently in this workshop it was reported that also for nonlinear channels a remarkable turbo decoding gain can be achieved (Siegrist et al., 2001). However, the classical turbo equalization relies on code rates at 1/3 up to 1/2 which makes it quite unattractive for high rate data transmission. Considering the potential of iterative equalization and decoding, we obtain a considerable turbo decoding gain also for high rate codes of less than 7% redundancy by using punctured convolutional codes and block codes.

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“…However, this leads to a nonrecoverable degradation which in return is small compared to the ideal case (Haunstein et al, 2004).…”

Section: Model Of Nonlinear Channelsmentioning

confidence: 98%

Turbo Equalization Of Nonlinear ISI-channels Using High Rate FEC Codes

et al. 2005

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“…This method is the basis of turbo equalization and is based on decoding methods for turbo codes [10]- [12] and has close connections to the iterative algorithms used in conjunction with so-called factor graphs [13]- [16]. This approach has been adapted to various communication tasks, ranging from detection and decoding of trellis coded modulation (TCM) [17], [18] and code division multiple access (CDMA) [19] to underwater acoustic communications [20]- [23] and optical fiber communications [24]- [26]. Over the last decade and a half, this joint, iterative approach has been applied to a vast array of problems that involve the use of an error control code to aid in the processing of another related task in the receive chain of a digital communication link.…”

Section: Turbo Equalization Overviewmentioning

confidence: 99%

Turbo Equalization: An Overview

Tüchler

Singer

2011

IEEE Trans. Inform. Theory

175

160

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Abstract-Turbo codes and the iterative algorithm for decoding them sparked a new era in the theory and practice of error control codes. Turbo equalization followed as a natural extension to this development, as an iterative technique for detection and decoding of data that has been both protected with forward error correction and transmitted over a channel with intersymbol interference (ISI). In this paper, we review the turbo equalization approach to coded data transmission over ISI channels, with an emphasis on the basic ideas, some of the practical details, and many of the research directions that have arisen from this offshoot, introduced by Douillard, et al. of the original turbo decoding algorithm. The subsequent relaxation of the maximum a posteriori (MAP) equalization algorithm to include linear and other simpler receivers sparked a decade and a half of research into iterative algorithms, spanning research problems ranging from trellis coded modulation to underwater acoustic communications.Index Terms-Equalization, iterative decoding, minimum mean square error, turbo equalization.

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“…In fact, although optical compensation has demonstrated to be very efficient in recovering signals affected by heavy penalties induced by PMD (see [1] and references therein), these devices need advanced and cost-ineffective technologies [2], so that the use of well-known and popular electronic schemes is of great interest. In the first-order approximation, the PMD effects are represented by the introduction of a differential group delay (DGD) between the two principal states of polarization (PSPs), causing intersymbol interference (ISI).…”

Section: Introductionmentioning

confidence: 99%

“…More effective electronic techniques, based on maximum-likelihood sequence detection (MLSD) implemented through the Viterbi algorithm (VA) [6], have been proposed in [2,3,5]. In [3], the presence of optical amplifiers is not considered.…”

Section: Introductionmentioning

confidence: 99%

“…As a consequence, the amplified spontaneous emission (ASE) noise is not present and the statistics of the received signal, necessary to compute the VA branch metrics are conditionally Gaussian due to shot and thermal noise. Since making a Gaussian assumption for noise statistics after photo-detection when ASE noise is dominant leads to inaccurate results in the computation of the receiver metrics [7], in [2,5] the statistics of the received signal are approximately measured and updated in real-time during transmission and assuming no decision errors. This method has been compared with classical equalization schemes in [2,5], showing that a better performance, as expected, can be obtained by using the MLSD strategy.…”

Section: Introductionmentioning

confidence: 99%

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Adaptive Electronic Processing in Optical PMD-Impaired Systems

Foggi

Colavolpe²,

Forestieri³

et al.

Optical Networks and Technologies

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Abstract:In high-speed optical transmission systems, one of the most challenging impairments is represented by the signal distortions produced by polarization-mode dispersion (PMD).In this paper, we analyze the limits of electronic compensation schemes, in the form of maximum-likelihood sequence detection receivers. With a constraint on the front-end processing after photo-detection, we compute the signal statistics necessary to implement this strategy. The receiver adaptivity is also discussed. The relevant performance is analyzed by means of computer simulations and accurate analytical performance bounds, and compared with the performance of all-optical compensators and decision-feedback equalizers. A significant performance loss with respect to optical compensation is observed for large values of the differential group delay (DGD) showing that, after the non reversible transformation operated by the photo-detector, it is not possible to effectively cope with the PMD-induced impairments.

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Principles for Electronic Equalization of Polarization-Mode Dispersion

Cited by 114 publications

References 18 publications

Turbo Equalization Of Nonlinear ISI-channels Using High Rate FEC Codes

Turbo Equalization Of Nonlinear ISI-channels Using High Rate FEC Codes

Turbo Equalization: An Overview

Adaptive Electronic Processing in Optical PMD-Impaired Systems

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