Armando Vannucci

• Ph.D.
• Professor (Assistant) at University of Parma

In the context of signal detection in the presence of an unknown time-varying channel parameter, receivers based on the Expectation Propagation (EP) framework appear to be very promising. EP is a message-passing algorithm based on factor graphs with an inherent ability to combine prior knowledge of system variables with channel observations. This s...

In the educational context, peer observation consists in teachers observing each other and involves constructive cooperation. For it to be beneficial for both observer and observee it requires clear objectives, a shared format and etiquette, and attention to the professional and the emotional components. The practice has become increasingly common...

We address the parallel implementation of a closed-loop symbol timing synchronizer in digital receivers. Starting from a serial timing recovery loop, we propose a low-complexity parallel architecture which, unlike parallel schemes available in the literature, employs a single numerically controlled oscillator, and is practically suitable for high-s...

We investigate the performance of free-space optical communication systems in the presence of atmospheric turbulence to assess the advantages that a coherent communication system can bring with respect to a conventional intensity modulation and direct detection (IM/DD) system. The perspective is an information-theoretic one, hence we evaluate the m...

This letter addresses the problem of signal detection in flat-fading channels. In this context, receivers based on the expectation propagation framework appear to be very promising although presenting some critical issues. We develop a new algorithm based on this framework where, unlike previous works, convergence is achieved after a single forward...

This paper aims at tackling the problem of signal detection in flat-fading channels. In this context, receivers based on the expectation propagation framework appear to be very promising although presenting some critical issues. We develop a new algorithm based on this framework where, unlike previous works, convergence is achieved after a single f...

In the frame of ongoing efforts between space agencies to define an on-off-keying-based optical low-Earth-orbit (LEO) direct-to-Earth (DTE) waveform, this paper offers an in-depth analysis of the Variable Data Rate (VDR) technique. VDR, in contrast to the currently adopted Constant Data Rate (CDR) approach, enables the optimization of the average t...

Gait and jump anomalies are often used as indicators to identify the presence and state of disorders that involve motor symptoms. Physical tests are often performed in specialized laboratories, which offer reliable and accurate results, but require long and costly analyses performed by specialized personnel. The use of inertial sensors for gait and...

In the frame of ongoing efforts between space agencies to define an on-off-keying-based optical low-Earth-orbit (LEO) direct-to-Earth (DTE) waveform, this paper offers an in-depth analysis of the Variable Data Rate (VDR) technique. VDR, in contrast to the currently adopted Constant Data Rate (CDR) approach, enables the optimization of the average t...

In the frame of ongoing efforts between space agencies to define an on-off-keying-based optical low-Earth-orbit (LEO) direct-to-Earth (DTE) waveform, this paper offers an in-depth analysis of the Variable Data Rate (VDR) technique. VDR, in contrast to the currently adopted Constant Data Rate (CDR) approach, enables the optimization of the average t...

Featured Application The communications scenario analyzed in this paper is typical of environments affected by strong electromagnetic interference (EMI), such as, e.g., power line communications or power substations. The transmission of random correlated samples with continuous values, which we analyze, can be seen both as a rough model for multica...

Nel contesto educativo, con peer observation si intende il processo in cui due (o più) colleghi si osservano l'un l'altro nello svolgimento dell'attività didattica al fine di migliorare la pratica didattica stessa di entrambe le parti ed ha quindi lo scopo di essere un'esperienza arricchente sia per chi è osservato, che per chi osserva. Perché lo s...

Impulsive noise is the main limiting factor for transmission over channels affected by electromagnetic interference. We study the estimation of (correlated) Gaussian signals in an impulsive noise scenarios. In this work, we analyze some of the existing as well as some novel estimation algorithms. Their performance is compared, for the first time, f...

Internet traffic detection and classification has been thoroughly studied in the last decade, but this is still a hot topic as regards the Internet of Things (IoT), a communication paradigm that is going to involve different aspects of our daily life. As a consequence, researchers started applying traditional methods for traffic classification also...

We propose a decoding algorithm for tail-biting convolutional codes over phase noise channels. It can be seen as a reduced complexity approximation of maximum-likelihood decoding. We target short blocks and extend the wrap-around Viterbi algorithm to trellises describing the random evolution of the phase impairment, for which we adopt two different...

We consider the estimation of correlated Gaussian samples in (correlated) impulsive noise, through message-passing algorithms. The factor graph includes cycles and, due to the mixture of Gaussian (samples and noise) and Bernoulli variables (the impulsive noise switches), the complexity of messages increases exponentially. We first analyze a simple...

Evaluating novel applications and protocols in realistic scenarios has always been a very important task for all stakeholders working in the networking field. Network emulation, being a trade-off between actual deployment and simulations, represents a very powerful solution to this issue, providing a working network platform without requiring the a...

Optical fiber-based biosensors are an emerging field of research with an extremely broad area of possible applications and a disruptive potential to turn the paradigm known as lab-on-fiber into reality. In the past few years, a variety of system choices has been explored, ranging from the type of sensing fiber, to the optical transducing element, t...

We study a nonlinear lossless polarizer (NLP), a fiber-based device able to control the polarization of an optical signal while preserving its energy. The NLP exploits the lossless polarization attraction (LPA) generated by the Kerr interactions between the signal and a fully polarized continuous wave (CW) pump. By employing a co-propagating pump,...

We propose an all-optical fiber-based device that is able to accomplish polarization control and OSNR enhancement of an amplitude modulated optical signal at the same time. The proposed device is made of a nonlinear lossless polarizer (NLP), which performs polarization control, followed by an ideal polarizing filter, which removes the orthogonally...

We propose an all-optical fiber-based device able to accomplish both polarization control and OSNR enhancement of an amplitude modulated optical signal, affected by unpolarized additive white Gaussian noise, at the same time. The proposed noise cleaning device is made of a nonlinear lossless polarizer (NLP), that performs polarization control, foll...

We characterize the performance of a nonlinear lossless polarizer, an all-optical fiber-based device that allows for the control of the state of polarization of an optical signal. The device relies on the lossless polarization attraction generated by the nonlinear interaction between the controlled signal and a controlling pump. Choosing a counter-...

We exploit a recently proposed nonlinear lossless polarizer to suppress the noise component that is (bitwise) orthogonal to an optical signal. It is shown how the proposed technique yields an optical signal-to-noise ratio (OSNR) gain close to 3dB and how this gain can be theoretically predicted, for different input OSNR values, from the degree of p...

In lossless polarization attraction, we find the optimal (co-propagating) pump wavelength placement and the related scaling rule, as a function of symbol period. We demonstrate that polarization attraction occurs only within a limited range of walk-off values.

We introduce a novel all-optical “noise cleaning” device, based on lossless polarization attraction, that provides an OSNR gain close to the theoretical 3dB limit. In addition, we demonstrate the robustness of polarization attraction against additive noise.

We study the performance of a nonlinear lossless polarizer (NLP), the device that transforms an input arbitrary state of polarization (SOP) of a signal beam into one and the same SOP toward the output and, unlike conventional passive polarizers, performs this transformation without polarization-dependent losses. The operation principle of this devi...

Following recent studies on Kerr-based polarization attractors, we characterize their performance by introducing the Degree Of Attraction. Results provide the guidelines for selecting pump power and fiber length, in the attractor’s design.

We introduce a simple and fast iterative algorithm, named SCAOS (simple counterpropagation algorithm for optical signals), for simulating the counterpropagation of optical signals within a nonlinear fiber. Being based on the split-step Fourier method, the algorithm is easily implementable in many traditional optical simulators. Applications of the...

We introduce a simple and fast SSFM-based algorithm, named SCAOS, for simulating the counter-propagation of optical signals. Applications to the vectorial counter-propagation of a polarized pump and probe demonstrate the phenomenon of lossless polarization attraction.

We investigate the interaction between Kerr nonlin- earity and polarization mode dispersion (PMD) in homogeneous multi-channel polarization division multiplexing coherent phase shift keying transmissions. Assuming linear distortions can be fully equalized by the coherent receiver, we concentrate the investigation on the residual nonlinear penalty....

We investigate for the first time the performance of PS-QPSK in WDM nonlinear propagation. We show that the theoretical performance improvement of PS-QPSK compared to PDM-QPSK is even larger in nonlinear propagation.

The complete documentation for Optilux, including the functions syntax and a background on the basics of an optical simulation

We present a rigorous investigation on how to optimize the degrees of freedom of optical polarization mode dispersion (PMD) compensators composed of differential group delay sections and polarization controllers, up to two stages. The analytical treatment relies on the extracted Jones matrices of the transmission and compensation fibers. The analys...

A novel state-variable model for semiconductor optical amplifiers (SOAs) that is amenable to block diagram implementation of wavelength division multiplexed (WDM) signals and fast execution times is presented. The novel model is called the reservoir model, in analogy with similar block-oriented models for Raman and erbium-doped fiber amplifiers (ED...

A novel state-variable dynamic model for semiconductor linear optical amplifiers (LOA) is used to describe gain dynamics and stabilization properties of LOAs. Results from the model are verified against experiments

We present a novel state-variable model for semi-conductor optical amplifiers, amenable to block diagram imple-mentation, and with fast execution times.

Numerical simulations of semiconductor optical amplifiers (SOA) often are time consuming. Making simplifying assumptions, we obtain a fast model based on the reservoir, representing the total number of useful carriers. In this paper, we explain how this model is developed and how the gain is parameterized. We demonstrate that the scattering losses,...

Optical amplification issues in packet-switched networks are often underestimated. In fact, EDFAs have been shown to be seriously impaired by burst-mode packet traffic, due to their internal time-dependent gain dynamics. In this scenario, Linear Optical Amplifiers (LOA) may find an interesting and cost-effective application. LOAs are novel gain-sta...

We investigate the static and dynamic properties of the recently introduced Linear Optical Amplifiers, as possible candidates to be used in the novel metro WDM packet network Wonder for optical node amplification. 1. Introduzione Nell'ambito dei Progetti di Ricerca di Rilevante Interesse Nazionale (PRIN), il Ministero dell'Istruzione, dell'Universi...

A novel analytical model is proposed to predict the cross-phase modulation (XPM)-induced depolarization in a two-channel transmission system, in which the Stokes' vector of each channel rotates around a space-invariant pivot by a time-varying angle which depends on the total instantaneous optical power in the fiber, on the angle between pump and pr...

We derive a closed-form expression for the DOP of polarized signals affected by XPM, in a modulated pump-probe scheme. Results are checked against simulations and experiments on a dispersion managed 3 ×100 km link.

In this paper, we report experiments on the statistical assessment of the reduction of PMD mitigator efficiency in presence of XPM effects. The XPM-induced depolarization limits compensation in polarization dispersive ultra-long haul system at 10 Gb/s.

In this paper we show that it is possible to describe exactly the field intensity distorted by polarization mode dispersion (PMD) at the output of a single-mode fiber, without resorting to the principal states of polarization (PSPs). Such description is based on the eigenmodes of what we call the extracted matrices, for which we establish relations...

A new maximum-likelihood sequence detection receiver for spectrally efficient linear modulations on bandlimited bandpass nonlinear channels is proposed. The receiver is based on oversampling the received signal corrupted by noise and nonlinear distortion. Contrary to other solutions in the literature, in the proposed technique there is no need for...

We proposed a novel semi-analytical technique for the evaluation of system outage probabilities in the presence of polarisation mode dispersion (PMD) at all-orders. Such technique relies on the rotational model for the fiber Muller matrix, whose rotational parameters were statistically characterized. Simulations of propagation can be performed eith...

The analytical results available for counter-propagating pump distributed Raman amplifiers in the undepleted pump approximation are shown to be easily extended to the signal-saturated case by using effective values of both input pump and signals

To obtain reliable PMD statistics from frequency-swept measurements of emulated fibres, criteria are provided to relate the measurement bandwidth to the fibre mean differential group delay and the number of frequency samples

We carry out a statistical characterization of Jones matrix eigenvalues and eigenmodes to gain deeper insight into recently proposed fiber models based on Jones matrix spectral decomposition. A set of linear dynamic equations for the Pauli coordinates of the Jones matrix is established. Using stochastic calculus, we determine the joint distribution...

Using a union bound on the error probability of optimal receivers for nonlinear channels, this work points out important factors affecting the error performance in the simple case of M-ary pulse amplitude modulation (M-PAM) with no intersymbol interference and unlimited transmission bandwidth. The performance is compared to that obtainable when the...

Based on a polynomial representation of a memoryless bandpass nonlinearity, a new realization of an optimal receiver is proposed to perform maximum likelihood detection of data sequences transmitted over nonlinear, possibly time-dispersive, channels. The receiver employs oversampling of the observed signal to compute proper branch metrics for a Vit...

The object of this study was the determination of acoustic correlates of two distinctive features of Italian stops related to voicing and point of articulation. The analysis was carried out on 648 VCV syllables. The correlates found for voicing were the sound bar during the voiced stops occlusion and the low?frequency (LF) burst energy. Informal pe...