Maria-Gabriella Di Benedetto

• PhD, IEEE Fellow
• Professor (Full) at currently Harvard University (home institution Sapienza University of Rome)

The year 2024 marked the 100th birthday of Kenneth N. Stevens (1924–2013), an eminent speech scientist, who by his vision inspired several generations of students and researchers, worldwide. This issue is to honor the ongoing value of Ken's seminal ideas that continue to inspire and influence—at the root—the work of those of us who pursue the goal...

The performance of Space Division Multiple Access (SDMA) in Multiuser Multiple Input Single Output (MU-MISO) systems degrades significantly under imperfect Channel State Information at the Transmitter (CSIT). To address this, Rate-Splitting Multiple Access (RSMA) has been shown to outperform SDMA in scenarios where CSIT is imperfect, particularly i...

The Narrowband Internet of Things (NB-IoT) technology has an important role in the mobile cellular ecosystem, enabling massive Machine Type Communication (mMTC) services. NB-IoT propagation was preliminarily analyzed via a measurement campaign carried out in 2020 in the city of Oslo, Norway. This investigation resulted in Oslo-2020, the first NB-Io...

Existing proposals for positioning in NB-IoT networks based on range estimation are characterized by either low accuracy or lack of compliance with 3GPP standards. While range-free approaches taking advantage of Machine Learning (ML) have been recently proposed as a potential way forward, their evaluation has been carried out only in simulated envi...

The Industrial Internet of Things (IIoT) paradigm has emerged as a transformative force, revolutionizing industrial processes by integrating advanced wireless technologies into traditional procedures to enhance their efficiency. The importance of this paradigm shift has produced a massive, yet heterogeneous, proliferation of scientific contribution...

A legacy software, “xkl,” developed in the 1980’s by Dennis Klatt in Kenneth N. Stevens’ Speech Communication Group at the Massachusetts Institute of Technology (MIT) has been recently revamped, thanks to a joint effort between MIT and Sapienza University of Rome (https://www.sciencedirect.com/science/article/pii/S2352711023001887). This collaborat...

Fifth Generation (5G) systems have been commercially available worldwide for at least a couple of years, with mid-band Non-Standalone (NSA) being the deployment mode preferred by Mobile Network Operators (MNOs). Empirical analyses have provided so far key insights on 5G NSA performance from different perspectives, but most of these works consider s...

Narrowband Internet of Things (NB-IoT) has quickly become a leading technology in the deployment of IoT systems and services, owing to its appealing features in terms of coverage and energy efficiency, as well as compatibility with existing mobile networks. Increasingly, IoT services and applications require location information to be paired with d...

Mobile networks are highly complex systems. Therefore, it is crucial to examine them from an empirical perspective to better understand how network features affect performance, so to suggest additional improvements. To this aim, this paper presents a large-scale dataset of measurements collected over fourth generation (4G) and fifth generation (5G)...

The successful rollout of fifth-generation (5G) networks requires a full understanding of the behavior of the propagation channel, taking into account the signal formats and the frequencies standardized by the Third Generation Partnership Project (3GPP). In the past, channel characterization for 5G has been addressed mainly based on the measurement...

The GEMMA database consists of recordings of disyllabic words: vowelconsonantvowel (VCV) for nongeminate cases and vowel consonantconsonantvowel (VCCV) for geminate cases. The consonants in the words are stops /b/, /d/, /g/, /p/, /t/, /k/, affricates /ts/, /dz/, /tf/, /dz/, fricatives /f/, /v/, /s/, /z/ (singleton only) and /∫/ (geminate only), nas...

The LaMIT database consists in recordings of 100 Italian sentences. The sentences in the database were designed so to include all phonemes of the Italian language, and also take into account the typical frequency of each phoneme in written Italian. Four native adult speakers of Standard Italian, raised and living in Rome, Italy, two female and two...

Mobility modeling in 5G and beyond 5G must address typical features such as time-varying correlation between mobility patterns of different nodes, and their variation ranging from macro-mobility (kilometer range) to micro-mobility (sub-meter range). Current models have strong limitations in doing so: the widely used reference-based models, such as...

Understanding radio propagation characteristics and developing channel models is fundamental to building and operating wireless communication systems. Among others uses, channel characterization and modeling can be used for coverage and performance analysis and prediction. Within this context, this paper describes a comprehensive dataset of channel...

Tens of different IoT platforms are currently available on the market as a result of the high interest in IoT, characterized by very different characteristics in terms of utilization models, features and availability. This paper provides a review of existing platforms, both adopting a closed source and an open source access model, focusing on five...

All Italian consonants affected by gemination, that is affricates, fricatives, liquids, nasals, and stops, were analyzed within a project named GEMMA that lasted over a span of about 25 years. Results of the analysis on stops, as published in (Esposito, A., and Di Benedetto, M. G. (1999). “Acoustic and Perceptual Study of Gemination in Italian Stop...

No PDF available ABSTRACT This study investigated how acoustic cues to features in Italian vowels are affected by lexical stress and tonal prominence. One aspect of an analysis on the LaMIT (Lexical Access Model for Italian) project, this study analyzed the impact of prosodic environment on acoustic cues to features. The LaMIT corpus consists of 10...

No PDF available ABSTRACT This study examined how tonal prominence impacts the acoustic cues to features of Italian vowels. It was one aspect of an analysis of the LaMIT (Lexical Access Model for Italian) project [Di Benedetto et al., “Speech recognition of spoken Italian based on detection of landmarks and other acoustic cues to distinctive featur...

Consonant gemination in Italian affricates and fricatives was investigated, completing the overall study of gemination of Italian consonants. Results of the analysis of other consonant categories, i.e. stops, nasals, and liquids, showed that closure duration for stops and consonant duration for nasals and liquids, form the most salient acoustic cue...

Modelling the process that a listener actuates in deriving the words intended by a speaker requires setting a hypothesis on how lexical items are stored in memory. This work aims at developing a system that imitates humans when identifying words in running speech and, in this way, provide a framework to better understand human speech processing. We...

User-centric radio access technology (RAT) selection is a key communication paradigm, given the increased number of available RATs and increased cognitive capabilities at the user end. When considered against traditional network-centric approaches, user-centric RAT selection results in reduced network-side management load, and leads to lower operat...

Two types of consonant gemination characterize Italian: lexical and syntactic. Italian lexical gemination is contrastive, so that two words may differ by only one geminated consonant. In contrast, syntactic gemination occurs across word boundaries and affects the initial consonant of a word in specific contexts, such as the presence of a monosyllab...

In overloaded Massive MIMO (mMIMO) systems, wherein the number K of user equipments (UEs) exceeds the number of base station antennas M, it has recently been shown that non-orthogonal multiple access (NOMA) can increase the sum spectral efficiency. This paper aims at identifying cases where code-domain NOMA can improve the spectral efficiency of mM...

The lack of publicly available large scale measurements has hindered the derivation of empirical path loss (PL) models for Narrowband Internet of Things (NB-IoT). Therefore, simulation-based investigations currently rely on models conceived for other cellular technologies, which are characterized, however, by different available bandwidth, carrier...

In the last years, the Internet of Things (IoT) has emerged as a key application context in the design and evolution of technologies in the transition toward a 5G ecosystem. More and more IoT technologies have entered the market and represent important enablers in the deployment of networks of interconnected devices. As network and spatial device d...

Two types of consonant gemination characterize Italian: lexical and syntactic. Italian lexical gemination is contrastive, so that two words may differ by only one geminated consonant. In contrast, syntactic gemination occurs across word boundaries, and affects the initial consonant of a word in specific contexts, such as the presence of a monosylla...

The purpose of this project was to derive a reliable estimate of the frequency of occurrence of the 30 phonemes - plus consonant geminated counterparts - of the Italian language, based on four selected written texts. Since no comparable dataset was found in previous literature, the present analysis may serve as a reference in future studies. Four t...

No PDF available ABSTRACT The purpose of this project was to derive a reliable estimate of the frequency of occurrence of the 30 phonemes – plus consonant geminated counterparts- of the Italian language, based on four selected written texts. Since no comparable dataset was found in previous literature, the present analysis may serve as a reference...

No PDF available ABSTRACT Modeling the process that a listener actuates in deriving words intended by a speaker, requires setting a hypothesis on how lexical items are stored in memory. Stevens’ model (2002) postulates that lexical items are stored in memory according to distinctive features, and that these features are hierarchically organized. Th...

Narrowband Internet of Things (NB-IoT) is gaining momentum as a promising technology for massive machine type communication. Given that its deployment is rapidly progressing worldwide, measurement campaigns and performance analyses are needed to better understand the system and move toward its enhancement. With this aim, this article presents a lar...

Narrowband Internet of Things (NB-IoT) is gaining momentum as a promising technology for massive Machine Type Communication (mMTC) and cellular Internet of Things (IoT). Given that its deployment is rapidly progressing worldwide, measurement campaigns and performance analyses are increasingly needed to better understand the system and move toward i...

All Italian consonants affected by gemination, that is affricates, fricatives, liquids, nasals and stops were analysed within a project named GEMMA that lasted over a span of about 25 years. Results of the analysis on stops, as published in a previous paper, had shown that the main acoustic cue to gemination in Italian is closure duration, while fr...

Consonant gemination in Italian affricates and fricatives was investigated, which completed the overall study of gemination of Italian consonants. Results of the analysis of the other consonant categories, i.e. stops, nasals, and liquids, had shown that closure duration for stops and consonant duration for nasals and liquids, form the most salient...

In overloaded Massive MIMO (mMIMO) systems, wherein the number K of user equipments (UEs) exceeds the number of base station antennas M, it has recently been shown that non-orthogonal multiple access (NOMA) can increase the sum spectral efficiency. This paper aims at identifying cases where code-domain NOMA can improve the spectral efficiency of mM...

Seamless location awareness is considered a cornerstone in the successful deployment of the Internet of Things (IoT). Support for IoT devices in indoor positioning platforms and, vice versa, availability of indoor positioning functions in IoT platforms, are however still in their early stages, posing a significant challenge in the study and researc...

In overloaded Massive MIMO systems, wherein the number K of user equipments (UEs) exceeds the number of base station antennas M, it has recently been shown that non-orthogonal multiple access (NOMA) can increase performance. This paper aims at identifying cases of the classical operating regime K < M, where code-domain NOMA can also improve the spe...

This document reports the main experimental results obtained by applying the proposed ViFi system in another testbed, referred to as w-iLab.t I, aiming to further validate the performance improvement of ViFi when compared to a traditional fingerprinting indoor positioning system. Reference Publication: "ViFi: Virtual Fingerprinting WiFi-based Ind...

Widespread adoption of indoor positioning systems based on WiFi fingerprinting is at present hindered by the large efforts required for measurements collection during the offline phase. Two approaches were recently proposed to address such issue: crowdsourcing and RSS radiomap prediction, based on either interpolation or propagation channel model f...

5G is the expected next step of the mobile cellular network evolution, and it is considered as the answer to the ongoing huge increase of cellular users and services. The architecture envisioned for 5G includes a large number of different network entities and systems that share a common spectrum resource via a dynamic spectrum access (DSA) approach...

Spectral efficiency of low-density spreading non-orthogonal multiple access channels in the presence of fading is derived for linear detection with independent decoding as well as optimum decoding. The large system limit, where both the number of users and number of signal dimensions grow with fixed ratio, called load, is considered. In the case of...

Motivated by recent theoretical challenges for 5G, this paper aims to position relevant results in the literature on code-domain non-orthogonal multiple access (NOMA) from an information-theoretic perspective, given that most of the recent intuition of NOMA relies on another domain, that is, the power domain. Theoretical derivations for several cod...

Time reversal, that is prefiltering of transmitted signals with time reversed channel impulse responses, may be used in single user communications in order to move complexity from the receiver to the transmitter, and in multiuser communications to also modify statistical properties of multiuser interference. Imperfect channel estimation may, howeve...

Multi-armed bandit (MAB) models are a viable approach to describe the problem of best wireless network selection by a multi-Radio Access Technology (multi-RAT) device, with the goal of maximizing the quality perceived by the final user. The classical MAB model does not allow, however, to properly describe the problem of wireless network selection b...

Ultra-wideband (UWB) and WiFi technologies have been widely proposed for the implementation of accurate and scalable indoor positioning systems (IPSs). Among different approaches, fingerprinting appears particularly suitable for WiFi IPSs and was also proposed for UWB IPSs, in order to cope with the decrease in accuracy of time of arrival (ToA)-bas...

Spectral efficiency of low-density spreading non-orthogonal multiple access channels in the presence of fading is derived for linear detection with independent decoding as well as optimum decoding. The large system limit, where both the number of users and number of signal dimensions grow with fixed ratio, called load, is considered. In the case of...

Time Reversal (TR) is a prefiltering scheme mostly analyzed in the context of centralized and synchronous IR-UWB networks, in order to leverage the trade-off between communication performance and device complexity, in particular in presence of multiuser interference. Several strong assumptions have been typically adopted in the analysis of TR, such...

5G-specific features, such as massive deployment, heterogeneity, and coexistence, call for innovative dynamic spectrum management mechanisms. Context-aware interoperability and interference control, and their integration, may be crucial to comply with spectrum efficiency and service optimization 5G requirements. Moving from the analysis of research...

5G is the expected next step of the mobile cellular network evolution, and it is considered as the answer to the ongoing huge increase of cellular users and services. The architecture envisioned for 5G includes a large number of different network entities and systems that share a common spectrum resource via a dynamic spectrum access (DSA) approach...

Mobility modeling in 5G and beyond 5G must address typical features such as time-varying correlation between mobility patterns of different nodes, and their variation ranging from macro-mobility (kilometer range) to micro-mobility (sub-meter range). Current models have strong limitations in doing so: the widely used reference-based models, such as...

Mobility modeling in 5G and beyond 5G must address typical features such as time-varying correlation between mobility patterns of different nodes, and their variation ranging from macro-mobility (kilometer range) to micro-mobility (sub-meter range). Current models have strong limitations in doing so: the widely used reference-based models, such as...

Widespread adoption of indoor positioning systems based on WiFi fingerprinting is at present hindered by the large efforts required for measurements collection during the offline phase. Two approaches were recently proposed to address such issue: crowdsourcing and RSS radiomap prediction, based on either interpolation or propagation channel model f...

The weighted k-nearest neighbors (WkNN) algorithm is by far the most popular choice in the design of fingerprinting indoor positioning systems based on WiFi received signal strength (RSS). WkNN estimates the position of a target device by selecting k reference points (RPs) based on the similarity of their fingerprints with the measured RSS values....

Time Reversal is well-known in Impulse Radio Ultra Wideband communications (IR-UWB) for its ability to improve performance and complexity both in noise limited scenarios and multiuser interference (MUI) limited ones. In an ad-hoc uncoordinated network, where no power control is possible, no users’ channels are known, or no elaborate multiple access...

Reliability and availability of sensing information gathered from Local Spectrum Sensing (LSS) by a single Cognitive Radio is strongly affected by the propagation conditions, period of sensing and geographical position of the device. For this reason, Cooperative Spectrum Sensing (CSS) was largely proposed in order to improve LSS performance by usin...

Introducing cognitive mechanisms at the application layer may lead to the possibility of an automatic selection of the wireless network that can guarantee best perceived experience by the final user. This chapter investigates this approach based on the concept of Quality of Experience (QoE), by introducing the use of application layer parameters, n...

Weighted k-Nearest Neighbors (WkNN) algorithms based on WiFi fingerprinting are a popular choice for 3D indoor position estimation. Performance of these schemes strongly depends however on the number of k Reference Points (RPs) used for the estimation. In this work a novel WiFi fingerprinting WkNN algorithm is proposed, that aims at improving posit...

This book, written by leading experts from academia and industry, offers a condensed overview on hot topics among the Cognitive Radios and Networks scientific and industrial communities (including those considered within the framework of the European COST Action IC0902) and presents exciting visions for the future. Examples of the subjects consider...

UWB radio has the potential to offer good performance in terms of localization precision. Time Reversal channel pre-filtering facilitates signal detection and also helps to increase the received energy in a targeted area. This paper assesses the quantitative and qualitative contributions of the Time Reversal (TR) technique associated with an Ultra...

This work proposes a novel framework for the organization and the management of a mobile cognitive radio network, focusing on the network performance in terms of cooperative spectrum sensing and data throughput. It relies on cooperation between secondary devices, that organize themselves in clusters defined according to both spectrum sensing reliab...

Detection, classification, and recognition based on the detection of energy features of Ultra Wide Band (UWB) vs. signals emitted in the Industrial Scientific and Medical (ISM) radio bands, such as Bluetooth, is a challenging issue. This work addressed this issue by analyzing the behavior of UWB versus Bluetooth signals in various noisy environment...

Prefiltering that is, linear processing at the transmitter side of a link, is often used in communication in order to simplify receivers, or to improve performance. Prefiltering requires at least a knowledge of the channel state. When this information is estimated, imperfect estimations impact achievable performance. Time reversal, that is a specia...

A model describing the cumulative effect of the independent access of $K$ users to a shared resource, which is formed by $N$ elements, is proposed, based on which an integer interference measure $zeta$ is defined. While traditional cases can be reconducted to reference well-known results, for which $zeta$ is either Gaussian or Poissonian, the propo...

Cooperative spectrum sensing has been proposed as a solution to increase the sensing function accuracy in cognitive radio networks, but the research has, so far, mainly focused on static scenarios, all but neglecting the impact of mobility on spectrum sensing. In this work a novel cooperative spectrum sensing scheme for mobile cognitive networks, b...

Impulse Radio Ultra Wide Band (IR-UWB) is a candidate technology in the deployment of cognitive underlay networks. Medium Access Control protocols for IR-UWB networks were however conceived in the past moving from considerations related to performance of the UWB networks, rather than from the need to coexist with other wireless systems. This chapte...

Automatic network recognition and classification may prove to be an important concept in the framework of cognitive radio and networks. For practical implementations, these operations must be carried out in a simple way by using simple devices and algorithms that require low computational load. The AIR-AWARE approach proposes to use MAC sub-layer f...

This book, written by experts from universities and major industrial research laboratories, is devoted to the very hot topic of cognitive radio and networking for cooperative coexistence of heterogeneous wireless networks. Selected highly relevant advanced research is presented on spectrum sensing and progress toward the realization of accurate rad...

Traditionally paired with impulsive communications, Time-Hopping CDMA (TH-CDMA) is a multiple access technique that separates users in time by coding their transmissions into pulses occupying a subset of Ns chips out of the total N included in a symbol period, in contrast with traditional Direct-Sequence CDMA (DS-CDMA) where Ns=N. The object of thi...

Recent evolution in regulation of access to TV channels allocated in UHF frequencies (DVB-T) makes vacant channels (TV White Spaces - TVWS) available to wireless data services. While this opportunity is currently widely studied by the cognitive radio community for communications, the use of TVWS for indoor positioning is all but unexplored. Frequen...

This work addresses the impact of sensing decision fusion rules and operative constraints on the performance of hard decision cooperative spectrum sensing schemes for cognitive radio networks. The work focuses on cooperative spectrum sensing under two sensing operating modes: the Constant False Alarm Rate (CFAR) and the Constant Detection Rate (CDR...

Multi-armed bandits may be used for modelling the process of selecting one among different wireless networks, given a set of system constraints typically formed by user-perceived network quality indicators. This work proposes a novel multi-armed bandit, that is made appropriate to the above context by introducing a distinction between two actions,...

Multiple-Input Single-Output (MISO) Ultra Wide Band (UWB) communications over a multipath channel is investigated. After introducing a tractable discrete-time multipath MISO channel model accounting for correlation between multiple channels, analytical results for single-user transmissions are drawn in the following two cases: no precoding at trans...

This paper introduces a transmit beamforming strategy taking into account the positions of primary, secondary victim and intended secondary receivers, to achieve underlay secondary access in multihop cognitive radio networking. The transmit beamforming strategy defines a novel path optimization scheme that deviates from a preselected path given by...

This work investigates the use of Time Reversal (TR) applied to UWB systems for communication and positioning applications. Potential performance boosts, that are achievable over a single UWB communication link by the sole adoption of TR, are investigated. In the case of multiuser UWB communications, it is shown that TR modifies the distribution of...

Cognitive radio networks operation relies on the capability to gather information about the surrounding environment, as regards both internal network status (presence and capabilities of other devices belonging to the same network) and external systems potentially coexisting with the cognitive network. In particular, retrieving information at the l...

Cooperative Spectrum Sensing (CSS) has been proposed as a solution to increase accuracy of spectrum sensing in a Cognitive Radio Network (CRN), but with a few exceptions the design and performance evaluation of CSS schemes has focused so far on static networks, neglecting the role and potential impact of terminals mobility, in conjunction with chan...

COST Action IC0902, “Cognitive Radio and Networking for Cooperative Coexistence of Heterogeneous Wireless Networks”, was launched in December 2009 and coordinates and integrates the research activities on cognitive radio and networks of more than 60 institutions and research projects throughout Europe and worldwide, involving more than 200 research...

Contemporary wireless systems must meet increased bandwidth requirements due to the persistent trend for higher multimedia data rates. Increased bandwidth may be achieved by developing efficient strategies for spectrum management. The cognitive radio (CR) concept proposes to push the dynamic spectrum access and efficient resource allocation beyond...

This work addresses the problem of cooperative spectrum sensing in cognitive radio networks, focusing on the impact of mobility on performance of cooperative sensing. First, a review of the most recent results on cooperative spectrum sensing is provided, resulting in the identification of measurement correlation and frame error rate in the reportin...