Studies in Error Correction Coding

For a proper understanding of the implementation of error correction coding schemes, a basic knowledge of communication channels and networks is necessary. Communication channels incur several types of errors, including noise and signal attenuation. Consequently, the benefits of a particular error control scheme are determined by the errors which occur most frequently. First, the types of transmissions across which errors occur will be considered. Subsequently, the types of errors that can appear during these transmissions and a short discussion of the cause of errors are necessary to understand the several types of errors that can occur. Afterward, the implementation of several major coding schemes will be discussed, including block codes, linear codes, and convolutional codes. Convolutional codes will specifically be discussed in terms of turbo codes and low-density parity check codes. Lastly, research of error correction coding schemes will involve several kinds of resources, including textbooks, journal articles, and technical publications. These resources will be used for the understanding of a practical implementation of an error correction coding scheme

Optical Time-Frequency Packing: Principles, Design, Implementation, and Experimental Demonstration

Time-frequency packing (TFP) transmission provides the highest achievable spectral efficiency with a constrained symbol alphabet and detector complexity. In this work, the application of the TFP technique to fiber-optic systems is investigated and experimentally demonstrated. The main theoretical aspects, design guidelines, and implementation issues are discussed, focusing on those aspects which are peculiar to TFP systems. In particular, adaptive compensation of propagation impairments, matched filtering, and maximum a posteriori probability detection are obtained by a combination of a butterfly equalizer and four 8-state parallel Bahl-Cocke-Jelinek-Raviv (BCJR) detectors. A novel algorithm that ensures adaptive equalization, channel estimation, and a proper distribution of tasks between the equalizer and BCJR detectors is proposed. A set of irregular low-density parity-check codes with different rates is designed to operate at low error rates and approach the spectral efficiency limit achievable by TFP at different signal-to-noise ratios. An experimental demonstration of the designed system is finally provided with five dual-polarization QPSK-modulated optical carriers, densely packed in a 100 GHz bandwidth, employing a recirculating loop to test the performance of the system at different transmission distances.Comment: This paper has been accepted for publication in the IEEE/OSA Journal of Lightwave Technolog

State-of-the-art in Power Line Communications: from the Applications to the Medium

In recent decades, power line communication has attracted considerable attention from the research community and industry, as well as from regulatory and standardization bodies. In this article we provide an overview of both narrowband and broadband systems, covering potential applications, regulatory and standardization efforts and recent research advancements in channel characterization, physical layer performance, medium access and higher layer specifications and evaluations. We also identify areas of current and further study that will enable the continued success of power line communication technology.Comment: 19 pages, 12 figures. Accepted for publication, IEEE Journal on Selected Areas in Communications. Special Issue on Power Line Communications and its Integration with the Networking Ecosystem. 201

Fifty Years of Noise Modeling and Mitigation in Power-Line Communications.

Building on the ubiquity of electric power infrastructure, power line communications (PLC) has been successfully used in diverse application scenarios, including the smart grid and in-home broadband communications systems as well as industrial and home automation. However, the power line channel exhibits deleterious properties, one of which is its hostile noise environment. This article aims for providing a review of noise modeling and mitigation techniques in PLC. Specifically, a comprehensive review of representative noise models developed over the past fifty years is presented, including both the empirical models based on measurement campaigns and simplified mathematical models. Following this, we provide an extensive survey of the suite of noise mitigation schemes, categorizing them into mitigation at the transmitter as well as parametric and non-parametric techniques employed at the receiver. Furthermore, since the accuracy of channel estimation in PLC is affected by noise, we review the literature of joint noise mitigation and channel estimation solutions. Finally, a number of directions are outlined for future research on both noise modeling and mitigation in PLC

Low-Complexity Iterative Receivers

La tesi affronta il problema delle comunicazioni digitali su canali con memoria, ponendo particolare enfasi su canali affetti da interferenza intersimbolica e canali affetti da rumore impulsivo. In particolare, l'analisi e il progetto vengono rivolti ai ricevitori ad oggi considerati come i più efficaci in tali scenari, ossia i ricevitori iterativi. Il fattore di qualità cruciale per un sistema di comunicazione viene considerato, nell'intera tesi, un conveniente compromesso tra complessità e prestazioni, piuttosto che le sole prestazioni. Il maggiore contributo del lavoro di tesi consiste in un insieme di ricevitori in grado di offrire, a parità di complessità, prestazioni migliori rispetto alle soluzioni di letteratura.The thesis addresses the problem of providing reliable communications over channels with memory, with particular emphasis on channels impaired by intersymbol interference and channels impaired by impulse noise. In particular, the receivers to date considered as the most effective for such scenarios, namely the iterative receivers, are investigated. Throughout the work, a convenient performance/complexity tradeoff, rather than the performance only, is considered as the key quality figure for a communication system. The main contribution the thesis provides is a set of low-complexity receivers that impressively outperform the existing receivers with similar complexity

Hybrid computer Monte-Carlo techniques

Hybrid analog-digital computer systems for Monte Carlo method application

Neutral coding - A report based on an NRP work session

Neural coding by impulses and trains on single and multiple channels, and representation of information in nonimpulse carrier

Time-Frequency Packing for High Capacity Coherent Optical Links

We consider realistic long-haul optical links, with linear and nonlinear impairments, and investigate the application of time-frequency packing with low-order constellations as a possible solution to increase the spectral efficiency. A detailed comparison with available techniques from the literature will be also performed. We will see that this technique represents a feasible solution to overcome the relevant theoretical and technological issues related to this spectral efficiency increase and could be more effective than the simple adoption of high-order modulation formats.Comment: 10 pages, 9 figures. arXiv admin note: text overlap with arXiv:1406.5685 by other author