H. Daniel - IEEE Xplore Author Profile

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Multiport network theory has been proved to be a suitable abstraction model for analyzing and optimizing reconfigurable intelligent surfaces (RISs) in an electromagnetically consistent manner, especially for studying the impact of the electromagnetic mutual coupling among radiating elements that are spaced less than half of the wavelength apart and for considering the interrelation between the amp...Show More
Consider a communication system in which a single-antenna user equipment exchanges information with a multi-antenna base station via a reconfigurable intelligent surface (RIS) in the presence of spatially correlated channels and electromagnetic interference (EMI). To exploit the attractive advantages of RIS technology, accurate configuration of its reflecting elements is crucial. In this paper, we...Show More
Reconfigurable intelligent surfaces (RIS) are a promising technology for enhancing wireless communication performance [M. Di Renzo et al., IEEE J. Sel. Areas Commun., 38, 2450–2525, 2020]. Conventional RIS models often simplify elements as ideal scatterers, but these models overlook key aspects like mutual coupling and phase-amplitude correlation [M. Di Renzo et al., Proc. IEEE, 110, no. 9, 1164–1...Show More
In this paper, we consider a reconfigurable intel-ligent surface (RIS) and model it by using multiport network theory. We first compare the representation of RIS by using the impedance and scattering parameters, by proving their equivalence and discussing their distinct features. Then, we develop an algorithm for optimizing the RIS configuration in the presence of electromagnetic mutual coupling. ...Show More
In this paper, we propose a novel framework that aims to jointly design the reflection coefficients of multiple reconfigurable intelligent surfaces and the precoding strategy of a single base station (BS) to optimize the self-tracking of the position and the velocity of a single multi-antenna user equipment (UE) that moves either in the far- or near-field region. Differently from the literature, a...Show More
In this work, we consider the precoder and multiple reconfigurable intelligent surfaces (RISs) optimization problem for a downlink multi-user multiple input multiple output (MIMO) communication scenario. In the proposed approach, the complexity of the RISs optimization is reduced by partitioning the RISs into tiles and formulating the problem as a tile assignment problem. To this end, we consider ...Show More
Reconfigurable intelligent surfaces (RISs) have tremendous potential to boost communication performance, especially when the line-of-sight (LOS) path between the user equipment (UE) and base station (BS) is blocked. To control the RIS, channel state information (CSI) is needed, which entails significant pilot overhead. To reduce this overhead and the need for frequent RIS reconfiguration, we propo...Show More
Joint localization and communication services have received growing interest for the next 6G cellular scenarios. Therefore, this paper studies a multi-Reconfigurable Intelligent Surface (RIS) single-user Multiple Input Multiple Output (MIMO) scenario from a dual perspective. From one side, we analyze the capabilities of an Extended Kalman Filter (EKF) to track the trajectory of the user by process...Show More
Resource allocation in interference-limited systems is a key enabler for beyond 5G (B5G) technologies, such as multi-carrier full duplex non-orthogonal multiple access (FD-NOMA). In FD-NOMA systems resource allocation is a computation-intensive non-convex problem due to the presence of strong interference and the integrality condition on channel allocation. In this letter, we propose an iterative ...Show More
With the advent of 5G and the research into beyond 5G (B5G) networks, a novel and very relevant research issue is how to manage the coexistence of different types of traffic, each with very stringent but completely different requirements. We propose a Deep Reinforcement Learning (DRL) algorithm to slice the available physical layer resources between ultra-reliable low-latency communications (URLLC...Show More
We study a multi-user multiple-input multiple-output interference network in the presence of multiple reconfigurable intelligent surfaces (RISs). The entire system is described by using a circuit-based model for the transmitters, receivers, and RISs. This is obtained by leveraging the electromagnetic tool of mutual impedances, which accounts for the signal propagation and the mutual coupling among...Show More
In this paper, we consider a multi-user multiple-input multiple-output (MIMO) system aided by multiple intelligent reflecting surfaces (IRSs) that are deployed to increase the coverage and, possibly, the rank of the channel. We propose an optimization algorithm to configure the IRSs, which is aimed at maximizing the network sum-rate by exploiting only the statistical characterization of the locati...Show More
In this article, we study the problem of power and channel allocation for multicarrier non-orthogonal multiple access (NOMA) full duplex (FD) systems. In such a system there are multiple interfering users transmitting over the same channel and the allocation task is a non-convex and extremely challenging problem. Following a block coordinated descent approach, we propose two algorithms based on th...Show More
In this letter we consider a resource allocation problem for multi-user MIMO non orthogonal multiple access (MU-MIMO-NOMA) downlink transmissions. Under the NOMA paradigm, users are organized in clusters of strong/weak pair and our aim is to find an optimal clustering, beamforming and power allocation scheme to minimize the power transmitted subject to a rate constraint for each user. Since the jo...Show More
The Fifth Generation of mobile networks is emerging as a key enabler for Ultra Reliable and Low Latency Communications. However, to effectively design and provide safety-critical applications through mobile systems, many research issues still need to be deeply investigated. The most important ones include: (1) the dynamic and flexible management of radio resources of a new Radio Access Network joi...Show More
The aim of this paper is to present a LoRa-based architecture to be used to monitor the formation of Black Powder (BP) in gas pipelines. The proposed network architecture is based on a multi-hop linear topology that allows to deploy a monitoring infrastructure that can be used to cover extremely long pipeline structures thanks to the wide transmission range of the LoRa technology. Together with th...Show More
This paper addresses the problem of weighted sum-rate maximization and mean squared error (MSE) minimization for the multiple-input multiple-output (MIMO) interference channel. Specifically, we consider a weighted minimum MSE architecture where each receiver employs successive interference cancellation (SIC) to separate the various received data streams and derive a hybrid beamforming scheme, wher...Show More
Frequency channel allocation is a key technique for improving the performance of cellular networks. In this paper, we address the channel allocation problem for a 5G multi-cell system. We consider a heterogeneous network in which cellular users, micro-cell users, and device-to-device (D2D) communications coexist within the radio footprint of the macro cell. We maximize the aggregate transmission r...Show More
The performance of the uplink of multiuser multiple input multiple output systems depends critically on the receiver architecture and on the quality of the acquired channel state information. A popular approach is to design linear receivers that minimize the mean squared error (MSE) of the received data symbols. Unfortunately, most of the literature does not take into account the presence of chann...Show More
We consider a variant of the decision fusion problem in the presence of Byzantines where the two states of the system under observation are not equiprobable. In this setup, the Byzantines can not adopt a simple corruption strategy consisting in flipping the local decisions regardless of the estimated state of the system. Doing so, in fact, they would reveal their presence to the fusion center, sin...Show More
We consider the optimal power allocation problem for an OFDMA small-cells network where the BSs operate in full-duplex mode. Although the problem formulation is not convex, we show that, leveraging on the intimate relationship between the minimum mean square error and the interference to noise ratio, it is possible to derive an iterative allocation scheme that provably converges to a local maximum...Show More
Device-to-device (D2D) communications are capable of enhancing the total cell throughput, reducing power consumption and increasing the instantaneous data rate. In this paper we propose a distributed power allocation scheme for D2D communications overlaying an OFDMA network, so that D2D communications take place on dedicated resources but are supervised by the BS. The proposed scheme addresses the...Show More
The implementation of device-to-device (D2D) underlaying or overlaying preexisting cellular networks has received much attention due to the potential of enhancing the total cell throughput, reducing the power consumption, and increasing the instantaneous data rate. In this paper, we propose a distributed power allocation scheme for D2D OFDMA communications and, in particular, we consider the two o...Show More
In this paper, we analyze a cognitive wireless scenario, where a primary wireless network (PWN) coexists with a cognitive (or secondary) wireless network (CWN). The PWN uses licensed spectrum and the nodes of the CWN cooperate to detect idle subchannels (not used by the PWN's nodes), possibly taking into account the knowledge of their positions'. On the basis of this scenario, we present a simple,...Show More
This paper investigates the subcarrier allocation problem for uplink transmissions in a multi-cell network, where device-to-device communications are enabled. We focus on maximizing the aggregate transmission rate in the system accounting for both inter- and intra-cell interference. This problem is computationally hard due to its nonconvex and combinatorial nature. However, we show that it can be ...Show More