arXiv subjects

Gunes Karabulut-Kurt

Publications and source records attributed to Gunes Karabulut-Kurt.

5 recordsLinked to original sources

arXiv2026

Secure Wireless Information Transfer and Energy Harvesting in HAPS-Based Network

High-altitude platform station (HAPS) serves as a promising enabler for wide-area connectivity of low-power wireless devices, particularly in remote and underserved regions. However, the strong line-of-sight characteristics of HAPS links increase the risk of eavesdropping, while the limited energy budget of ground devices remains a major operational constraint. In this work, we propose a secure wireless information and energy harvesting framework for HAPS-based networks in the presence of spatially distributed eavesdroppers. The proposed system integrates friendly jamming and power transfer nodes equipped with null-steering capability antennas, such that they not only degrade the reception quality at eavesdroppers but also act as additional radio-frequency energy sources for legitimate users. A time-switching wireless information and power transfer architecture is adopted at the user side. Under this framework, we derive tractable expressions for the joint rate-energy coverage and the average secrecy rate using stochastic geometry tools. Numerical and Monte Carlo results validate the developed analysis and reveal key design trade-offs among the time allocation factor, null-steering-zone radius around each user, and jammer transmit power. In particular, the results show that properly coordinated null-steering jamming can simultaneously support secure communication and adequate wireless power transfer, while an appropriate choice of system parameters, such as time allocation factor and jamming power, is required to balance harvested energy, communication reliability, and secrecy performance.

cs.IT↗

arXiv2025

A User Centric Group Authentication Scheme for Secure Communication

Group Authentication Schemes (GAS) are methodologies developed to verify the membership of multiple users simultaneously. These schemes enable the concurrent authentication of several users while eliminating the need for a certification authority. Numerous GAS methods have been explored in the literature, and they can be classified into three distinct generations based on their foundational mathematical principles. First-generation GASs rely on polynomial interpolation and the multiplicative subgroup of a finite field. Second-generation GASs also employ polynomial interpolation, but they distinguish themselves by incorporating elliptic curves over finite fields. While third-generation GASs present a promising solution for scalable environments, they demonstrate a limitation in certain applications. Such applications typically require the identification of users participating in the authentication process. In the third-generation GAS, users are able to verify their credentials while maintaining anonymity. However, there are various applications where the identification of participating users is necessary. In this study, we propose an improved version of third-generation GAS, utilizing inner product spaces and polynomial interpolation to resolve this limitation. We address the issue of preventing malicious actions by legitimate group members. The current third-generation scheme allows members to share group credentials, which can jeopardize group confidentiality. Our proposed scheme mitigates this risk by eliminating the ability of individual users to distribute credentials. However, a potential limitation of our scheme is its reliance on a central authority for authentication in certain scenarios.

cs.CR↗

arXiv2025

Temporal Spectrum Analysis for Multi-Constellation Space Domain Awareness

Space Domain Awareness (SDA) system has different major aspects including continues and robust awareness from the network that is crucial for an efficient control over all actors in space. The observability of the space assets on the other hand requires efficient analysis on when and how observed space objects can be controlled. This becomes crucial when real-world spatial dynamics are taken into account as it introduces complexities into the system. The real-world dynamics can reveal the structure of the network including isolated and dominant stations. We propose a Temporal Spectrum Analysis (TSA) scheme that takes into account a set of real-world parameters including actual dynamics of the objects in space to analyze the structure of a ground-space network that inherits temporal spectrum as the key element of design. We study the potential interactions between multiple constellations using TSA and conduct a comprehensive real-world simulations to quantify the structure of the network. Numerical results show how the temporal spectrum of each satellite affects the intra- and inter-constellation network structure including interactions between ground stations and constellations.

cs.NI↗

arXiv2025

Energy-Efficient Satellite IoT Optical Downlinks Using Weather-Adaptive Reinforcement Learning

Internet of Things (IoT) devices have become increasingly ubiquitous with applications not only in urban areas but remote areas as well. These devices support industries such as agriculture, forestry, and resource extraction. Due to the device location being in remote areas, satellites are frequently used to collect and deliver IoT device data to customers. As these devices become increasingly advanced and numerous, the amount of data produced has rapidly increased potentially straining the ability for radio frequency (RF) downlink capacity. Free space optical communications with their wide available bandwidths and high data rates are a potential solution, but these communication systems are highly vulnerable to weather-related disruptions. This results in certain communication opportunities being inefficient in terms of the amount of data received versus the power expended. In this paper, we propose a deep reinforcement learning (DRL) method using Deep Q-Networks that takes advantage of weather condition forecasts to improve energy efficiency while delivering the same number of packets as schemes that don't factor weather into routing decisions. We compare this method with simple approaches that utilize simple cloud cover thresholds to improve energy efficiency. In testing the DRL approach provides improved median energy efficiency without a significant reduction in median delivery ratio. Simple cloud cover thresholds were also found to be effective but the thresholds with the highest energy efficiency had reduced median delivery ratio values.

cs.NI↗

arXiv2022

Future Space Networks: Toward the Next Giant Leap for Humankind

Due to the unprecedented advances in satellite fabrication and deployment, innovative communications and networking technologies, ambitious space projects and programs, and the resurgence of interest in satellite networks, there is a need to redefine space networks (SpaceNets) to incorporate all of these evolutions. This paper introduces a vision for future SpaceNets that considers advances in several related domains. First, we present a reference architecture that captures the various network entities and terminals in a holistic manner. Based on this, space, air, and ground use cases are studied. Then, the architectures and technologies that enable the envisaged SpaceNets are investigated. In so doing, we highlight the activities and projects of different standardization bodies, satellite operators, and national organizations towards the envisioned SpaceNets. Finally, the challenges, potential solutions, and open issues from communications and networking perspectives are discussed.

cs.NI↗