arXiv subjects

Diana Pamela Moya Osorio

Publications and source records attributed to Diana Pamela Moya Osorio.

8 recordsLinked to original sources

arXiv2025

Radio over Fiber with Cascaded Structure: Algorithm for Uplink Positioning

Recent advancements in polymer microwave fiber (PMF) technology have created significant opportunities for robust, low-cost, and high-speed sub-terahertz (THz) radio-over-fiber communications. Recognizing these potential benefits, this paper explores a novel radio-over-fiber (RoF) structure that interconnects multiple radio units (RUs) in cascade via fiber, envisioning its application in indoor scenarios. This structure creates a number of research opportunities when considering cascaded distortion effects introduced by non-linear power amplifiers (PAs) at the RUs and the propagation channel over the fiber. We propose maximum-likelihood and non-linear least-squares algorithms to estimate the propagation distance along the RoF and the time-of-arrival between the RoF and the user equipment. For the case of linear PAs, we derive the Cramér-Rao lower bound to benchmark the performance of the estimators. Finally, we investigate the use of the system for uplink positioning. Our simulation results demonstrate that the proposed estimators perform satisfactorily even with the cascaded effects of non-linear PAs, and that the deployment of this RoF structure can enable new cost-effective opportunities for high-resolution positioning in indoor scenarios. In the numerical evaluation, we also use measured PMF characteristics for high-density polyethylene fibers.

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arXiv2025

Propagation Distance Estimation for Radio over Fiber with Cascaded Structure

Recent developments in polymer microwave fiber (PMF) have opened great opportunities for robust, low-cost, and high-speed sub-terahertz (THz) communications. Noticing this great potential, this paper addresses the problem of estimation of the propagation distance of a sub-Thz signal along a radio over fiber structure. Particularly, this paper considers a novel cascaded structure that interconnects multiple radio units (RUs) via fiber for applications in indoor scenarios. Herein, we consider the cascaded effects of distortions introduced by non-linear power amplifiers at the RUs, and the propagation channel over the fiber is based on measurements obtained from transmissions of sub-THz signals on high-density polyethylene fibers. For the estimation of the propagation distance, non-linear least-squares algorithms are proposed, and our simulation results demonstrate that the proposed estimators present a good performance on the propagation distance estimation even in the presence of the cascaded effect of non-linear PAs.

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arXiv2025

Privacy-Aware Design of Distributed MIMO ISAC Systems

Integrated Sensing and Communication (ISAC) systems raise unprecedented challenges regarding security and privacy since related applications involve the gathering of sensitive, identifiable information about people and the environment, which can lead to privacy leakage. Privacy-aware measures can steer the design of ISAC systems to prevent privacy violations. Thus, we explore this perspective for the design of distributed massive multiple-input multiple-output ISAC systems. For this purpose, we introduce an adversarial model where a malicious user exploits the interference from ISAC signals to extract sensing information. To mitigate this threat, we propose an iterative privacy-aware framework of two blocks: precoder design and access point selection. The precoder design aims to minimize the mutual information between the sensing and communication signals by imposing constraints on sensing and communication performance and maximum transmit power. The access point selection also aims to minimize the mutual information between communication and sensing signals by strategically selecting access points that transmit ISAC signals, and sensing receivers. Results show a reduction in the effectiveness of the attack measured by the probability of detection of the attacker.

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arXiv2023

Strategic Deployment of Swarm of UAVs for Secure IoT Networks

Security provisioning for low-complex and constrained devices in the Internet of Things (IoT) is exacerbating the concerns for the design of future wireless networks. To unveil the full potential of the sixth generation (6G), it is becoming even more evident that security measurements should be considered at all layers of the network. This work aims to contribute in this direction by investigating the employment of unmanned aerial vehicles (UAVs) for providing secure transmissions in ground IoT networks. Toward this purpose, it is considered that a set of UAVs acting as aerial base stations provide secure connectivity between the network and multiple ground nodes. Then, the association of IoT nodes, the 3D positioning of the UAVs and the power allocation of the UAVs are obtained by leveraging game theoretic and convex optimization-based tools with the goal of improving the secrecy of the system. It is shown that the proposed framework obtains better and more efficient secrecy performance over an IoT network than state-of-the-art greedy algorithms for positioning and association.

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arXiv2023

Multi UAV-enabled Distributed Sensing: Cooperation Orchestration and Detection Protocol

This paper proposes an unmanned aerial vehicle (UAV)-based distributed sensing framework that uses orthogonal frequency-division multiplexing (OFDM) waveforms to detect the position of a ground target, and UAVs operate in half-duplex mode. A spatial grid approach is proposed, where an specific area in the ground is divided into cells of equal size, then the radar cross-section (RCS) of each cell is jointly estimated by a network of dual-function UAVs. For this purpose, three estimation algorithms are proposed employing the maximum likelihood criterion, and digital beamforming is used for the local signal acquisition at the receive UAVs. It is also considered that the coordination, fusion of sensing data, and central estimation is performed at a certain UAV acting as a fusion center (FC). Monte Carlo simulations are performed to obtain the absolute estimation error of the proposed framework. The results show an improved accuracy and resolution by the proposed framework, if compared to a single monostatic UAV benchmark, due to the distributed approach among the UAVs. It is also evidenced that a reduced overhead is obtained when compared to a general compressive sensing (CS) approach.

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arXiv2022

Secrecy Capacity Maximization for a Hybrid Relay-RIS Scheme in mmWave MIMO Networks

The hybrid relay-reflecting intelligent surface (HR-RIS) has been recently introduced as an efficient solution to overcome the double path loss and limited beamforming diversity of the conventional fully passive reflecting surface. This motivates us to investigate the application of the HR-RIS in improving the secrecy capacity of millimeter wave multiple-input-multiple-output (MIMO) systems with the presence of multi-antenna eavesdropper. The joint optimization of the transmit beamformer and the relay-reflecting coefficients at RIS is tackled via alternating optimization. In the proposed solution, a closed-form expression for the optimal transmit beamformer at the transmitter is derived, and a metaheuristic solution based on particle swarm optimization is proposed to optimize the active and passive elements at the HR-RIS. The simulation results verify that under various scenarios, the HR-RIS provides significant improvement in the secrecy capacity with respect to the conventional passive reflecting surface.

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arXiv2020

Survey on Physical Layer Security for 5G Wireless Networks

Physical layer security is a promising approach that can benefit traditional encryption methods. The idea of physical layer security is to take advantage of the features of the propagation medium and its impairments to ensure secure communication in the physical layer. This work introduces a comprehensive review of the main information-theoretic metrics used to measure the secrecy performance in physical layer security. Furthermore, a theoretical framework related to the most commonly used physical layer security techniques to improve the secrecy performance is provided. Finally, our work surveys physical layer security research over several enabling 5G technologies, such as massive multiple-input multiple-output, millimeter-wave communications, heterogeneous networks, non-orthogonal multiple access, and full-duplex. Also, we include the key concepts of each of the aforementioned technologies. Future fields of research and technical challenges of physical layer security are also identified.

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arXiv2020

On the Secrecy Performance Over N-Wave with Diffuse Power Fading Channel

We investigate the physical layer security over N-wave with diffuse power (NWDP) fading model, which is typically encountered in realistic wireless scenarios in the context of millimeter-wave communications and emerging 5G technologies. More specifically, novel and exact expressions of the secrecy outage probability (SOP) and the lower bound of the secrecy outage probability are derived in terms of well-known elementary and special functions. Furthermore, we provide very useful insights on the impact of increasing: the number, the relative amplitudes and the power of the dominant specular components for improving secrecy performance. In this context, we show that it is possible to achieve a very good secrecy performance when: (i) the relative amplitudes of the dominant specular components for the eavesdropper channel are sufficiently large compared to those relative amplitudes of the dominant components for the legitimate channel eavesdropper channel, and (ii) the power of the Bob's dominant components is significantly greater than the power of the Eve's dominant rays. The validity of the proposed expressions is confirmed via Monte Carlo simulations.

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