Paolo Banelli

• PhD
• Università degli Studi di Perugia at University of Perugia

This paper introduces conformal Lyapunov optimization (CLO), a novel resource allocation framework for networked systems that optimizes average long-term objectives, while satisfying deterministic long-term reliability constraints. Unlike traditional Lyapunov optimization (LO), which addresses resource allocation tasks under average long-term const...

This paper presents a performance analysis of centralized spectrum sensing based on compressed measurements. We assume cooperative sensing, where unlicensed users individually perform compressed sensing and send their results to a fusion center, which makes the final decision about the presence or absence of a licensed user signal. Several cooperat...

In machine learning applications, data are often high-dimensional and intricately related. It is often of interest to find the underlying structure and Granger causal relationships among the data and represent these relationships with directed graphs. In this paper, we study multivariate time series, where each series is associated with a node of a...

The Information Bottleneck (IB) method is an information theoretical framework to design a parsimonious and tunable feature-extraction mechanism, such that the extracted features are maximally relevant to a specific learning or inference task. Despite its theoretical value, the IB is based on a functional optimization problem that admits a closed f...

The seamless integration of multiple radio access technologies (multi-RAT) and cloud/edge resources is pivotal for advancing future networks, which seek to unify distributed and heterogeneous computing and communication resources into a cohesive continuum system, tailored for mobile applications. Many research projects and focused studies are propo...

Edge Learning (EL) pushes the computational resources toward the edge of 5G/6G network to assist mobile users requesting delay-sensitive and energy-aware intelligent services. A common challenge in running inference tasks from remote is to extract and transmit only the features that are most significant for the inference task. From this perspective...

Internet of Things (IoT) applications combine sensing, wireless communication, intelligence, and actuation, enabling the interaction among heterogeneous devices that collect and process considerable amounts of data. However, the effectiveness of IoT applications needs to face the limitation of available resources, including spectrum, energy, comput...

Edge Learning (EL) pushes the computational resources toward the edge of 5G/6G network to assist mobile users requesting delay-sensitive and energy-aware intelligent services. A common challenge in running inference tasks from remote is to extract and transmit only the features that are most significant for the inference task. From this perspective...

Digital terrestrial video broadcasting systems based on orthogonal frequency division multiplexing (OFDM), such as second generation of terrestrial digital video broadcasting standard (DVB-T2), often include carriers reserved for peak-to-average power ratio (PAPR) reduction. This paper presents a low-complexity PAPR reduction method that inserts co...

Goal-oriented communications represent an emerging paradigm for efficient and reliable learning at the wireless edge, where only the information relevant for the specific learning task is transmitted to perform inference and/or training. The aim of this paper is to introduce a novel system design and algorithmic framework to enable goal-oriented co...

Theoretical analysis of orthogonal frequency division multiplexing (OFDM) systems, equipped at the receiver by a non-linear impulsive noise suppressor, is very challenging. Indeed, although an exact closed-form expression for the output signal-to-noise ratio (SNR) of such OFDM systems is available for widely used impulsive noise models, theoretical...

We study decentralized estimation of time-varying signals at a fusion center, when energy harvesting sensors transmit sampled data over rate-constrained links. We propose dynamic strategies to select radio parameters, sampling set, and harvested energy at each node, with the aim of estimating a time-varying signal while ensuring: i) accuracy of the...

Theoretical analysis of orthogonal frequency division multiplexing (OFDM) systems equipped at the receiver by a non-linear impulsive noise suppressor is a challenging topic in communication systems. Indeed, although an exact closed-form expression for the output signal-to-noise ratio (SNR) of such OFDM systems is available for widely used impulsive...

We study decentralized estimation of time-varying signals at a fusion center, when energy harvesting sensors transmit sampled data over rate-constrained links. We propose dynamic strategies to select radio parameters, sampling set, and harvested energy at each node, with the aim of estimating a time-varying signal while ensuring: i) accuracy of the...

A critical challenge in graph signal processing is the sampling of bandlimited graph signals; signals that are sparse in a well-defined graph Fourier domain. Current works focused on sampling time-invariant graph signals and ignored their temporal evolution. However, time can bring new insights on sampling since sensor, biological, and financial ne...

We compare the main multicarrier modulation formats when employed over channels with nonlinear amplification. Using a general and unified discrete‐time model that encompasses orthogonal frequency division multiplexing (OFDM) and its most popular alternatives, we perform a comparison using the achievable spectral efficiency, computed in the presence...

This paper presents a feasibility study for a very high data rate receiver operating in the K/Ka-band suitable to future Moon exploration missions. The receiver specifications are outlined starting from the mission scenario and from a careful system analysis. The designed architecture uses a low noise front-end to down-convert the incoming K/Ka-ban...

This paper proposes and discusses two software implementations of the DVB-T modulator, using C++ and MATLAB, respectively. All the key features of the DVB-T standard are included. The C++ DVB-T modulator, incorporated into the Iris framework developed by Trinity College of Dublin, works in real time on an Intel Core i7 2.4 GHz CPU with the Iris tes...

Multicarrier wireless communication systems, which usually operate over frequency-selective fading channels, are practically also impaired by environmental impulsive noise. In order to boost the signal-to-noise power ratio (SNR) at the receiver, this paper proposes and analyzes non-linear estimators based on the multiple thresholding, with associat...

The aim of this chapter is to give an overview of the recent advances related to sampling and recovery of signals defined over graphs. First, we illustrate the conditions for perfect recovery of bandlimited graph signals from samples collected over a selected set of vertexes. Then, we describe some sampling design criteria proposed in the literatur...

One of the most crucial challenges in graph signal processing is the sampling of bandlimited graph signals, i.e., signals that are sparse in a well-defined graph Fourier domain. So far, prior art is mostly focused on (sub)sampling single snapshots of graph signals ignoring their evolution over time. However, time can bring forth new insights, since...

The goal of this paper is to propose novel strategies for adaptive learning of signals defined over graphs, which are observed over a (randomly time-varying) subset of vertices. We recast two classical adaptive algorithms in the graph signal processing framework, namely, the least mean squares (LMS) and the recursive least squares (RLS) adaptive es...

The goal of this paper is to propose novel strategies for adaptive learning of signals defined over graphs, which are observed over a (randomly time-varying) subset of vertices. We recast two classical adaptive algorithms in the graph signal processing framework, namely, the least mean squares (LMS) and the recursive least squares (RLS) adaptive es...

Finite impulse response (FIR) graph filters play a crucial role in the field of signal processing on graphs. However, when the graph signal is time-varying, the state of the art FIR graph filters do not capture the time variations of the input signal. In this work, we propose an extension of FIR graph filters to capture also the signal variations o...

The aim of this paper is to propose distributed strategies for adaptive learning of signals defined over graphs. Assuming the graph signal to be band-limited, the method enables distributed reconstruction, with guaranteed performance in terms of mean-square error, and tracking from a limited number of sampled observations taken from a subset of ver...

The aim of this paper is to propose distributed strategies for adaptive learning of signals defined over graphs. Assuming the graph signal to be bandlimited, the method enables distributed reconstruction, with guaranteed performance in terms of mean-square error, and tracking from a limited number of sampled observations taken from a subset of vert...

The aim of this paper is to propose a least mean squares (LMS) strategy for adaptive estimation of signals defined over graphs. Assuming the graph signal to be band-limited, over a known bandwidth, the method enables reconstruction, with guaranteed performance in terms of mean-square error, and tracking from a limited number of observations sampled...

We focus on the performance of the energy detector for cognitive radio applications. Our aim is to incorporate, into the energy detector, low-complexity algorithms that compute the performance of the detector itself. The main parameters of interest are the probability of detection and the required number of samples. Since the exact performance anal...

Finite impulse response (FIR) graph filters play a crucial role in the field of signal processing on graphs. However, when the graph signal is time-varying, the state of the art FIR graph filters do not capture the time variations of the input signal. In this work, we propose an extension of FIR graph filters to capture also the signal variations o...

The minimum mean-squared error (MMSE) is one of the most popular criteria for Bayesian estimation. Conversely, the signal-to-noise ratio (SNR) is a typical performance criterion in communications, radar, and generally detection theory. In this paper we first formalize an SNR criterion to design an estimator, and then we prove that there exists an e...

The minimum mean-squared error (MMSE) is one of the most popular criteria for Bayesian estimation. Conversely, the signal-to-noise ratio (SNR) is a typical performance criterion in communications, radar, and generally detection theory. In this paper we first formalize an SNR criterion to design an estimator, and then we prove that there exists an e...

In many applications spanning from sensor to social networks, transportation systems, gene regulatory networks or big data, the signals of interest are defined over the vertices of a graph. The aim of this paper is to propose a least mean square (LMS) strategy for adaptive estimation of signals defined over graphs. Assuming the graph signal to be b...

The aim of this paper is to propose a least mean squares (LMS) strategy for adaptive estimation of signals defined over graphs. Assuming the graph signal to be band-limited, over a known bandwidth, the method enables reconstruction, with guaranteed performance in terms of mean-square error, and tracking from a limited number of observations over a...

Impulsive noise typically represents a man-made disturbance that, although it may impair any electrical device, is often neglected in the performance analysis of wireless communication systems. This paper exploits some recent results on Bayesian estimators of Gaussian sources impaired by Middleton Class-A noise, in order to investigate the usefulne...

Orthogonal Frequency-Division Multiplexing (OFDM) is probably the topic that in the last two decades has motivated and attracted most of the research efforts and standardization activities for the physical layer of digital communication systems. Aim of this paper is to introduce the subject as a natural evolution from classical single-carrier (SC)...

Fifth-generation (5G) cellular communications promise to deliver the gigabit experience to mobile users, with a capacity increase of up to three orders of magnitude with respect to current long-term evolution (LTE) systems. There is widespread agreement that such an ambitious goal will be realized through a combination of innovative techniques invo...

5G cellular communications promise to deliver the gigabit experience to mobile users, with a capacity increase of up to three orders of magnitude with respect to current LTE systems. There is widespread agreement that such an ambitious goal will be realized through a combination of innovative techniques involving different network layers. At the ph...

This paper deals with a smart sensing strategy in an overlay cognitive radio network, to effectively exploit secondary-user (SU) transmitting opportunities, while preserving primary-user (PU) interference. Specifically, we consider a non-periodic sensing policy characterized by different transmitting and silence periods, and we derive closed-form e...

This paper describes the design and validation of a Software Defined Radio (SDR) testbed, which can be used for Digital Television transmission using the Digital Video Broadcasting -Terrestrial (DVB-T) standard. In order to generate a DVB-T-compliant signal with low computational complexity, we design an SDR architecture that uses the C/C++ languag...

We examine the small sample size performance of the energy detector for spectrum sensing in AWGN. By making use of the cube-of-Gaussian approximation of chi-squared random variables, we derive a novel, simple, and accurate analytical expression for the minimum number of samples required to achieve a desired probability of detection and false alarm....

This paper focuses on sensing-throughput tradeoffs for overlay cognitive radio networks. The goal is to maximize the opportunistic secondary user throughput, by limiting the disturbance to primary user activity. Specifically, by assuming that a Poisson birth-death process characterizes the primary user traffic, the sensing-time bounds are imposed b...

We consider a cooperative communication system where the destination node receives an orthogonal frequency-division multiplexing (OFDM) signal transmitted from two relay nodes. We propose and compare two pilot-aided algorithms for the estimation of the carrier frequency offsets (CFOs) and the channel impulse responses (CIRs) associated with the two...

This paper deals with coded-excitation techniques for ultrasound medical echography. Specifically, linear Huffman coding is proposed as an alternative approach to other widely established techniques, such as complementary Golay coding and linear frequency modulation. The code design is guided by an optimization procedure that boosts the signal-to-n...

This chapter focuses on orthogonal frequency division multiplex (OFDM) transmissions over time-varying channels. OFDM, also known as multicarrier modulation, relies on the concept of parallel data transmission in the frequency domain and mainly owes its success to the easy equalization for linear time-invariant (LTI) frequency-selective channels. I...

Channel state information (CSI) is indispensable for coherent detection in a wireless communication system. The pilot-aided method is one of the most intensively studied approaches for channel estimation. This method is especially attractive for time-varying channels because of their short coherence time. This chapter discusses pilot-aided channel...

We investigate the error probability for Alamouti space-time coded orthogonal frequency-division multiplexing (OFDM) systems with carrier frequency offset (CFO) and multipath fading channels. Our main assumptions are: frequency-selective Rayleigh fading, a single receive antenna, and coherent detection. We derive new closed-form results for the (sy...

The paper focuses on minimum mean square error (MMSE) Bayesian estimation for a Gaussian source impaired by additive Middleton's Class-A impulsive noise. In addition to the optimal Bayesian estimator, the paper considers also the soft-limiter and the blanker, which are two popular suboptimal estimators characterized by very low complexity. The MMSE...

This paper investigates the statistical properties of non-linear transformations (NLT) of random variables, in order to establish useful tools for estimation and information theory. Specifically, the paper focuses on linear regression analysis of the NLT output and derives sufficient general conditions to establish when the input-output regression...

We evaluate the probability of error of linearly modulated signals, such as phase-shift keying (PSK) and quadrature amplitude modulation (QAM), in the presence of Gaussian cochannel interference (CCI) and Rayleigh fading channels. Specifically, we assume that the fading channel of the CCI is maximally correlated with the fading channel of the signa...

This paper analyzes the quality of service (QoS) of scheduling algorithms for heterogeneous users in multi-user (MU) wireless systems that take advantage from a cross-layer design with both adaptive modulation and coding (AMC) and automatic repeat request (ARQ). By developing a general theoretical framework based on a finite-state Markov chain, we...

In OFDM systems, fast time-varying channels can be effectively estimated and tracked by coupling a channel basis expansion model with a Kalman filtering approach. Although the Kalman filter is asymptotically MSE-optimal when the channel statistics are known, it may suffer some performance degradation in the presence of statistical mismatches. We pr...

Terrestrial or Handheld Digital Video Broadcasting (DVB-T/H) and Terrestrial Digital Multimedia Broadcasting (T-DMB) are two popular broadcasting standards that enable digital television transmissions to handheld receivers. This paper presents a comprehensive performance comparison between the physical layers of DVB-T/H and T-DMB when employed for...

This paper deals with the design of coded-excitation signal for medical ultrasound imaging. In order to design a code sequence that generates an ultrasound signal with good detail resolution and signal-to-noise ratio, both in frequency-dependent and frequency-independent attenuating media, we propose to use a linear Huffman code obtained by an effi...

We present iterative turbo-like equalizers for multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems subject to frequency-selective channels with rapid time variation. The proposed equalizers are obtained from a Bayesian approach based on the unbiased minimum mean-squared error (MMSE) criterion, but also ad...

A multibeam satellite system can be modelled as a multiple-input multiple-output (MIMO) system with an interbeam interference matrix that is derived from the positions of the users in the different beams. This way it is possible to apply precoding techniques, such as Tomlinson-Harashima precoding (THP), to mitigate the interference. This paper pres...

A multibeam satellite system can be modelled as a multiple-input multiple-output (MIMO) system with an inter-beam interference matrix that is derived from the positions of the users in the different beams. This way it is possible to apply precoding techniques, such as Tomlinson-Harashima precoding (THP), to mitigate the interference. This paper pre...

The use of telemedicine capabilities to manage aged and cardiac chronically ill patients is going to become a common practice. Usefulness and diagnostic value of classical ECG monitoring and recording can be enhanced by jointly collecting and analysing data detected by other sensors (e.g. movement detectors) which enable to associate specific cardi...

This paper proposes a novel simulation model to characterize the bit-error rate (BER) performance of coded orthogonal frequency-division multiplexing (OFDM) systems that are affected by the Doppler spread. The proposed equivalent frequency-domain OFDM model (EFDOM) avoids the exact generation of the time-varying channel by introducing several param...

We consider frequency domain equalization of single-carrier systems in doubly-selective channels. In this framework, we investigate the role of channel extension in the time domain on the performance of extended frequency-domain equalization. Specifically, we propose a new low-complexity channel extension technique, whose comparison with other tech...

This paper deals with the detection of pacemaker pulses in an electrocardiogram (ECG) waveform. In order to realize a pulse detector that is robust to a wide-band electromyographic (EMG) noise, we propose a (patent pending) fully digital approach that exploits a two step filtering strategy, followed by a threshold comparison. By resorting to comput...

This paper deals with the analytical evaluation of the average delay, the packet-loss rate (PLR) and the throughput of a multi-user (MU) wireless system that capitalizes on a cross-layer design of adaptive modulation and coding (AMC) with automatic repeat request (ARQ). To this end, we propose a heuristic scheduling policy, which has the nice prope...

We compare some block equalizers for single-carrier satellite systems subject to hard propagation conditions such as high Doppler spread, non-line-of-sight (NLOS), and non-negligible multipath fading. These impairments are relevant when the very high speed of a mobile receiver forces to use a non-directional antenna. First, we compare low-complexit...

This paper develops a novel simulation model to characterize the bit error rate (BER) performance of coded orthogonal frequency-division modulation (OFDM) systems affected by Doppler spread. This simulation model, which acts directly in the frequency domain, greatly enhances the simulation efficiency, while maintaining a very good accuracy. By this...

OFDM systems affected by severe time-varying channels greatly benefit from equalization schemes based on intercarrier interference (ICI) mitigation, which guarantee improved performance with respect to conventional one-tap equalizers. By exploiting a semi- analytical approach, this paper assesses the BER performance of the so-called banded equalize...

In this paper, we deal with channel estimation for orthogonal frequency-division multiplexing (OFDM) systems. The channels are assumed to be time-varying (TV) and approximated by a basis expansion model (BEM). Due to the time-variation, the resulting channel matrix in the frequency domain is no longer diagonal, but approximately banded. Based on th...

This paper considers a pilot-aided/data-aided Kalman channel estimator for OFDM in fast time-varying (TV) channels. Capitalizing on a basis expansion model (BEM) and on a frequency-domain estimation philosophy, the OFDM system is designed to periodically switch between a pilot-aided and a data-aided mode in order to reduce the rate penalty introduc...

Recently, several approaches have been proposed for the equalization of orthogonal frequency-division multiplexing (OFDM) signals in challenging high-mobility scenarios. Among them, a minimum mean-squared error (MMSE) block linear equalizer (BLE), based on a band LDL factorization, is particularly attractive for its good tradeoff between performanc...

In this paper, we deal with channel estimation for orthogonal frequency-division multiplexing (OFDM) systems. The channels are assumed to be time-varying (TV) and approximated by a basis expansion model (BEM). Due to the time-variation, the resulting channel matrix in the frequency domain is no longer diagonal, but can be approximated as banded. Ba...

In this paper, we propose adaptive channel estimation for orthogonal frequency division multiplexing (OFDM) in fast time-varying (TV) channels. A basis expansion model (BEM) approach is used to capture the time variation of the channel within each OFDM block, and to reduce the estimator dimensionality. Capitalizing on the BEM structure and on a fre...

In this paper, we deal with channel estimation for orthogonal frequency-division multiplexing (OFDM) systems. The channels are assumed to be time-varying (TV) and approximated by a basis expansion model (BEM). Due to the time-variation, the resulting channel matrix in the frequency domain is no longer diagonal, but can be approximated as banded. Ba...

Multicarrier systems are seriously affected by time-varying frequency-selective channels. Recently, windowing and decision-feedback equalization (DFE) have separately been proven to boost the performance of minimum mean-squared error (MMSE) block equalization, while maintaining a very low complexity by capitalizing on a band LDL factorization. This...

Abstract-A multicarrier direct-sequence code-division multiple-access (MC-DS-CDMA) downlink system with linear precoding over a group of subcarriers is considered. This scheme preserves user orthogonality independently of the underlying frequency-selective channel, collects the channel diversity and enables low-complexity decoding. In this context,...

We introduce an analytical approach to evaluate the error probability of orthogonal frequency-division-multiplexing (OFDM) systems subject to carrier frequency offset (CFO) in frequency-selective channels, characterized by Rayleigh or Rician fading. By properly exploiting the Gaussian approximation of the intercarrier interference (ICI), we show th...

We present a block minimum mean-squared error (MMSE) equalizer for orthogonal frequency-division multiplexing (OFDM) systems over time-varying multipath channels. The equalization algorithm exploits the band structure of the frequency-domain channel matrix by means of a band LDL^H factorization. The complexity of the proposed algorithm is...

Recently, a minimum mean-squared error (MMSE) block linear equalizer based on a band LDL^H factorization has been proposed for equalization of orthogonal frequency-division multiplexing (OFDM) systems affected by Doppler spread. In this paper, we extend this approach towards two directions. First, we design an MMSE block decision-feedback...

We present a low-complexity equalizer for multicarrier code-division multiple-access (MC-CDMA) downlink systems over time-varying (TV) multipath channels with non-negligible Doppler spread. The equalization algorithm, which is based on a block minimum mean-squared error (MMSE) approach, exploits the band structure of the frequency-domain channel ma...

The performance of multicarrier systems is highly impaired by intercarrier interference (ICI) due to frequency synchronization errors at the receiver and by intermodulation distortion (IMD) introduced by a nonlinear amplifier (NLA) at the transmitter. In this paper, we evaluate the bit-error rate (BER) of multicarrier direct-sequence code-division...

In multiuser code-division multiple-access (CDMA) environments, the ill-conditioning of the covariance matrix of the received signal may degrade the performance of minimum mean-squared error (MMSE) detectors, especially when few samples are available for the covariance matrix estimation. In order to mitigate this performance degradation, we propose...

In multicarrier systems, the time variation of the multipath channel generates intercarrier interference (ICI). In this paper, we investigate ICI mitigation techniques that rely on a band approximation of the minimum mean-squared error (MMSE) block linear equalizer (BLE). We show that windowing is an effective method to reduce the ICI at the output...

The aim of this paper is to examine the effects of the nonlinear distortions introduced by the high-power amplifier in the downlink of direct-sequence code-division multiple-access systems. By modeling the nonlinear distortion effects as a signal power loss and a superimposed colored Gaussian noise, we derive the symbol-error rate (SER) of the mini...

This paper presents an analytical approach to evaluate the error probability of orthogonal frequency-division multiplexing (OFDM) systems subject to carrier frequency offset (CFO) in frequency-selective channels, characterized by Rayleigh or Rician fading. By exploiting the Gaussian approximation of the intercarrier interference (ICI), we show that...

Linear precoding is a well known effective technique to boost the performance of orthogonal frequency-division multiplexing (OFDM) systems. A drawback of linearly precoded OFDM (LP-OFDM) systems is the high computational complexity required by maximum-likelihood (ML) detection, which is mandatory to capture all the channel diversity. Conversely, lo...