Search Results (277)

The integration of satellite and terrestrial networks within the same spectrum is a key enabler for extending mobile connectivity in future communication systems. In this context, the Direct Connectivity between Mobile Satellite Service and International Mobile Telecommunications user equipment (DC-MSS-IMT) paradigm, currently under study within the International Telecommunication Union foresees the use of terrestrial IMT frequency bands by satellite systems to directly serve conventional mobile devices. This paper presents an experimental study to assess the coexistence between a terrestrial 5G-NR receiver and a co-channel interfering signal representative of a Low Earth Orbit (LEO) satellite downlink. A controlled laboratory setup in a conducted configuration was implemented to ensure repeatability and accurate control of interference conditions. Measurements were performed over four carrier frequencies representative of IMT bands (763 MHz, 1482 MHz, 2150 MHz, and 2635 MHz), considering different traffic load conditions (100% and 50%) and Doppler shifts associated with satellite motion. The interference impact was evaluated in terms of receiver desensitization, defined as the increase in the total received power relative to the baseline noise level. The results show that a 1 dB desensitization threshold is consistently reached when the interfering signal power is approximately 5–6 dB below the receiver noise floor, corresponding to an interference-to-noise ratio (I/N) of about −6 dB. This behavior is observed across all tested frequency bands, traffic conditions, and Doppler scenarios, indicating limited sensitivity to frequency offsets within the considered range. The findings confirm the validity of commonly adopted coexistence criteria and provide experimentally derived reference values to support ongoing regulatory and technical studies on spectrum sharing between satellite and terrestrial IMT systems. Full article

Mode coupling in multimode step-index polymer optical fibers (SI POFs) plays a critical role in determining signal integrity and bandwidth performance in optical communication systems. It originates from intrinsic random perturbations that influence power distribution among propagating modes, making accurate prediction of steady-state distributions (SSDs) essential for reliable system design. In this work, we model mode coupling as a stochastic process using the Langevin equation, incorporating simulated Langevin forces to numerically evaluate modal power evolution and steady-state behavior. The proposed approach demonstrates strong agreement with previously reported experimental results, validating its capability to capture energy redistribution mechanisms induced by fiber imperfections. From a telecommunications perspective, the model provides valuable insights into modal dispersion, bandwidth limitations, and signal degradation in SI POF-based links. These results establish a robust and efficient framework for analyzing and optimizing multimode SI POFs, supporting their application in high-speed data transmission and short-reach optical communication networks. Full article

Embedding large language model (LLM) coordinators in production electronic systems, connected vehicles, multi-robot fabrics, IoT control loops, telecommunications orchestration, demands a pre-delivery filter stage that preserves ethical guarantees under adversarial influence at deployment scale. We present a constitutional governance layer that filters compiled influence policies before they reach a heterogeneous population of grounded LLM agents whose hybrid decision model combines a game-theoretic base probability with an LLM-evaluated narrative shift attenuated by per-agent resistance. Four experiments on a Barabási–Albert scale-free network of 30 agents powered by Llama-3.3-70B-Instruct show that the filter holds an Ethical Cooperation Score (ECS) of $0.176$ (multi-seed mean $0.163$, 95% confidence interval (CI) $[0.150,0.174]$) against an unconstrained baseline of $\mathrm{ECS}=0$, enforced by a hard integrity gate ($1.000$ vs. $0.000$). We surface an autonomy paradox in which unconstrained agents resist manipulation more forcefully ($0.856$ vs. $0.728$) yet collapse to $\mathrm{ECS}=0$, establishing that system-level integrity cannot be delegated to agent-level defence. The advantage is monotonic in resistance ($+0.174$ to $+0.183$), seed-stable (Cliff’s $\delta =1.0$, complete separation), topology- and backbone-invariant across five contemporary LLMs, robust to alternative ECS formulations, and reproduces at N = 100. Against constitutional artificial intelligence (CAI) critique-revise and LlamaGuard-style safety-classifier baselines, the framework matches the integrity floor and adds a measurable margin on the secondary risk surface (burst timing, composite manipulation risk). The filter runs at 0.78 μs/call ($\approx 1.3\times {10}^6$ decisions/s/core), supporting always-on deployment as a stateless, model-agnostic component of LLM agent pipelines in adversarially contested electronic systems. Full article

A spectrum analyzer is an essential instrument in telecommunications for observing and analyzing the power distribution of a signal across different frequencies. Traditionally, these devices are expensive and complex, limiting their accessibility. This paper presents an affordable spectrum analyzer prototype using a software-defined radio (SDR) module and a Raspberry Pi, coupled with a 10.1-inch touchscreen. Based on the HackRF One and Raspberry Pi 4B+, the system uses GNU Radio to capture, analyze, and display electromagnetic-signal spectra from 1 MHz to 6 GHz. The user-friendly interface and artificial intelligence-based voice module enable easy, accessible real-time selection of frequencies, bandwidth adjustment, and signal visualization, applicable to 5G and 6G networks. Full article

The UK telecommunications sector’s 5G rollout is projected to consume 2.1% of national electricity by 2030, raising urgent sustainability concerns. This study empirically investigates, under controlled laboratory conditions, the energy performance and cost characteristics of two private 5G architectures—Vodafone’s Mobile Private Network (MPN) and an Open Radio Access Network (O-RAN) via BubbleRAN—and contextualises them against public network references and the United Nations Sustainable Development Goals (SDGs). Two complementary dimensions of energy performance are assessed: absolute power consumption (Watts), reflecting total system draw regardless of throughput; and throughput efficiency (Mbps/W), capturing useful data delivered per unit of energy. In terms of absolute power, O-RAN consumes less (460 W active, 378 W idle) than MPN (645 W active, 620 W idle). In terms of throughput efficiency, MPN delivers 1.45 Mbps/W versus O-RAN’s 0.44 Mbps/W under these specific controlled, single-cell conditions, a difference that reflects the tested hardware configurations (n77 vs. n78 band; 936 Mbps vs. 202 Mbps throughput; 2 × 2 vs. 4 × 4 MIMO) as much as any intrinsic architectural distinction. Both architectures offer substantially lower annual energy costs (£1060–£1486) compared to public micro-cells (£1991–£2666), representing 44–60% savings. Session continuity was 100% across all controlled trials; this reflects short-term laboratory conditions and should not be extrapolated to a long-term network availability guarantee without extended field validation. These results are configuration-specific preliminary indicators; the relative efficiency advantage of each architecture is expected to vary with load, band, and deployment scale. By 2030, UK 5G network operations are projected to generate 795,347–1,260,532 tonnes of CO₂ annually across low-to-high demand scenarios; private deployment, by reducing site proliferation 15–33%, could displace a meaningful share of this footprint. These findings support SDGs 4, 8, 9, 12, and 13. Hybrid O-RAN–MPN pilots are recommended to maximise sustainability gains while advancing social equity and net-zero targets. Full article

We propose and experimentally validate an automatic urban water leakage detection architecture that leverages dark fiber links already deployed in telecommunication networks in underground conduits in the vicinity of water pipelines. The sensing stage relies on a differential-phase coherent optical time-domain reflectometry interrogator enhanced with optical pulse compression to improve sensitivity. Building on this vibration acquisition stage, automatic leakage detection algorithms are implemented by searching for leak-induced activity in the frequency domain, which is well suited to revealing leakage-related features. After acquiring a baseline calibration to characterize normal-condition vibrations at each sensing position, leakage candidates are identified by comparing distribution-based metrics computed over multiple measurements against the corresponding baseline statistics. Two automatic leakage detection strategies are developed. First, low-complexity feature-based metrics are implemented, enabling continuous monitoring with minimal computational requirements. Second, an autoencoder-based anomaly detection technique is introduced, which also relies on location-specific normal-condition calibration but reduces the dependence on prior knowledge of the expected leakage vibration signatures. A real-world field trial on an urban network demonstrates reliable detection and localization using controlled leak events generated in the field, with measurements performed over a 17 km sensing fiber and an effective spatial resolution of 2.6 m. Benchmarking against a commercial punctual electro-acoustic leak detector yields consistent trends. Overall, the proposed system could complement existing technologies by enabling automated, continuous city-scale monitoring over already deployed dark fiber infrastructure. Full article

The rapid evolution of the Open Radio Access Network (O-RAN) architecture and the exponential growth in specification complexity create significant barriers for researchers translating 5G standards into practical implementations. Existing evaluation frameworks for large language models, such as ORAN-Bench-13K, focus predominantly on the theoretical comprehension of regulatory documents while neglecting the critical aspect of software execution. This disparity results in a profound semantic gap, defined here as the structural and conceptual misalignment between abstract normative requirements and their concrete realization in the source code of open platforms like srsRAN. To bridge this divide and enable advanced cognitive reasoning, this paper presents a Hybrid Retrieval-Augmented Generation (RAG) framework designed to unify two heterogeneous knowledge domains: the O-RAN/3GPP specification corpus and the srsRAN C++ codebase. The proposed architecture leverages a hierarchical Parent–Child Chunking strategy to preserve the structural integrity of complex code and normative protocols. Additionally, it introduces a probabilistic Semantic Query Routing mechanism that dynamically selects the relevant context domain based on query intent. This routing actively mitigates semantic interference—a phenomenon where merging conflicting cross-domain terminology introduces informational noise, which our baseline tests showed degrades response accuracy by 4.7%. Empirical evaluation demonstrates that the hybrid approach successfully overcomes this, achieving an overall accuracy of 76.70% and outperforming the standard RAG baseline of 72.00%. Furthermore, system performance analysis reveals that effective context filtering reduces the average response generation latency to 3.47 s, compared to 3.73 s for traditional RAG methods, rendering the framework highly suitable for real-time telecommunications engineering tasks. Full article

Coaxial cable plays a vital role in the wide application of telecommunications, network, and television broadcasting and other fields, with its transmission performance directly affecting signal quality and transmission efficiency. In practical applications, the length of the cable and the terminal load state of the connection often affect the stability of the signal. In order to solve this problem, we used STMicroelectronics STM32F407VET6 (STMicroelectronics, Geneva, Switzerland) as the master controller in this system, and deduced the length of the cable by analyzing the functional relationship between the length of the cable and the open circuit frequency. An open cable is regarded as a capacitor, and any two core wires are regarded as two plates of a flat capacitor. The linear relationship between open frequency and length is used to detect the length of the coaxial cable. The system then determines whether the terminal load is capacitance or resistance based on the detected frequency. If no frequency is detected, then the load is considered resistance. The system detects the resistance value of the resistor through series voltage division. If a frequency is detected, this indicates that the load is capacitance. At this time, the system uses an RC oscillation circuit composed of HGSEMI ICL8038 (Huagao Semiconductor Co., Ltd., Wuxi, China) for testing, and provides the phase shift required by the corresponding signal through the RC network, so as to detect the capacitance value. Finally, we successfully designed a coaxial cable length and terminal load detection system based on STM32F407VET6. Through this system, the user can accurately understand the length of the coaxial cable and the load of the connection terminal, which provides a reliable guarantee for the stability of signal transmission. Full article

The differential distribution of cellular towers of Telkomsel, Indonesia’s largest mobile network operator, in Banten Province, Indonesia, poses challenges to network performance and service reliability. Therefore, we developed a novel hybrid framework that integrates geographic information systems, minimum spanning tree modeling, and signal-weighted k-nearest neighbor classification to assess tower utilization and signal coverage. Leveraging geospatial data from 110 Telkomsel cellular towers and 1000 simulated user nodes, it was found that 2.73% of towers were overloaded and 189 signal blank spots were identified in rural and topographically complex areas. By incorporating both spatial topology and signal strength sensitivity, the developed method outperforms conventional spatial or machine learning approaches in preserving spatial fidelity and supporting infrastructure planning. Despite the use of simulated user data, the framework demonstrates high scalability and adaptability for integration with real-time network performance metrics, enabling dynamic and location-specific telecommunication optimization. Full article

Digitalization of railway traffic dispatching systems is a key step in the modernization of railway telecommunication infrastructure. This paper presents a case study of the migration from legacy analog technology to a software-centric dispatching platform that integrates digital signal processing, optical fiber transmission, and Internet Protocol (IP)-based network architectures, as implemented in the Serbian railway system. The modernization is performed through an iterative, incremental process: existing analog dispatcher equipment and established operating procedures are preserved, while digital dispatching centers, trackside communication nodes, and radio-dispatching services are introduced gradually. This staged evolution enables high-capacity, noise-resilient communication and seamless interconnection between the old and the new subsystems without disrupting railway operations. The adoption of software-based control and integrated digital signal processing provides modular scalability, real-time system supervision, automated diagnostics, and improved maintainability. One of critical services within the new architecture, the Centralized Call Record- and Message-Archiving System (CCRMAS), provides a centralized platform that captures, secures, and retrieves operational railway communication in real time for monitoring, post-incident analysis, and regulatory compliance. The resulting architecture, deployed within Serbian Railways, establishes a scalable and resilient foundation for future automation, interoperability, and integration within intelligent railway traffic-management environments. Thus, the paper extracts a generalizable hybrid migration architecture model and transferable design principles, supported by deployment artifacts and illustrated through migration scenarios, that can be applied to the modernization of other legacy-intensive railway networks. Full article

This paper presents the development and investigation of an intelligent control system for a high-frequency ozone generator integrated into an IoT-based and telecommunication environment. A cyber-physical nonlinear mathematical model combining the electrical, thermal, gas-dynamic, and chemical subsystems of the ozone generation process is proposed. The model was implemented in discrete-time form and experimentally validated using the corona–discharge-based high-frequency ozonator ETRO-02. The deviation between simulation and experimental results did not exceed 5.3% for settling time, 6.7% for overshoot, 1.6% for steady-state ozone concentration, and 0.9% for gas temperature, confirming the adequacy of the proposed model. Based on this model, a hierarchical two-level intelligent control architecture is synthesized, consisting of a fast local control loop with a cycle time of 1–5 ms and a supervisory monitoring layer. The proposed adaptive state-feedback control law with online gain adjustment ensures stable real-time operation under nonlinear dynamics, ±20% parameter variations, network delays of 1–10 ms, and packet loss probabilities of up to 5%. As a result, the settling time is reduced from 420 ms to 160 ms, the overshoot from 12.5% to 3.1%, and the steady-state error from 6.5% to 1.6%, while the specific energy consumption decreases from 11.8 to 6.2 Wh/m³. The obtained results demonstrate that the integration of a cyber-physical model with a millisecond-level intelligent control system significantly improves the dynamic performance, robustness, and energy efficiency of high-frequency ozone generators compared to classical control and monitoring-oriented IoT systems. Unlike cloud-centric IoT monitoring architectures that operate at second-level update cycles, the proposed system closes the control loop locally at the millisecond scale, enabling stabilization of fast nonlinear electro-plasma dynamics. The results demonstrate that edge-intelligent adaptive control significantly enhances both dynamic performance and energy efficiency, confirming the feasibility of millisecond-level cyber-physical regulation for industrial ozone generation systems. Full article

Vehicular ad hoc networks (VANETs) require authentication systems that balance privacy, scalability, and post-quantum security. While lattice-based V-LDAA offers quantum resistance, it faces challenges in signature size, traceability, and integration. We propose post-quantum traceable direct anonymous attestation (PQ-TDAA), combining National Institute of Standards and Technology (NIST)-standard Dilithium2 and Falcon-512 signatures with adapted Beullens-style blind signatures and Fiat–Shamir simplified Schnorr proofs, reducing proof size by 69.2% (8 kB vs. V-LDAA’s 26 kB) and supporting European Telecommunications Standards Institute Technical Specification (ETSI TS) 102 941-compliant traceability through Road Side Unit (RSU)-assisted verification. Evaluated using SageMath, Python 3.11, and NS-3, PQ-TDAA-Falcon-512 achieves 8.1 ms and 49.7 ms end-to-end delays at 10 and 20 vehicles, respectively, with 64.7 Mbps goodput on congested 802.11p channels, showing promise for densities of ≤50 vehicles and advantages over Dilithium2. Real-world validation on ARM Cortex-A76 (Raspberry Pi 5, emulating automotive OBUs) yields sub-0.5 ms V2V cycles within 100 ms beacon intervals, supporting practical embedded deployment. Future work will extend PQ-TDAA to emerging 5G and NR-V2X settings, integrate more realistic mobility and channel models through coupled NS-3 and SUMO co-simulation, and investigate side-channel resistance for enhanced scalability and robustness in real deployments. Full article

Telemedicine at the national scale must balance clinical quality, privacy, latency, and sustainability. This study aims to develop a system architecture and methodology for low-energy edge AI combined with green data center routing to reduce energy per consultation while maintaining clinical-grade performance. The results present (1) an energy-aware edge inference stack for physiological sensing and video triage; (2) a carbon-aware, service level agreement (SAL)-constrained routing strategy across regional data centers using software-defined networking and dynamic workload placement; (3) a techno-environmental methodology linking patient-level service key performance indexes to energy neutrality factor, grams CO₂e per encounter, and latency–reliability envelopes; and (4) national rollout playbooks covering network tiers (household/clinic/edge/cloud), facilities upgrades, and governance. Scenarios in urban, peri-urban, and rural/remote environments show 37–62% energy savings and 28–49% carbon reductions relative to cloud-only baselines, with median end-to-end latency ≤120 ms for triage and ≤40 ms for vitals alarms, meeting the World Health Organization and the International Telecommunication Union latency expectations for eHealth. Trade-offs, risks (drift, network volatility), and policy levers (green SLAs, data residency, open standards) are evaluated to scale sustainable telemedicine without compromising safety or equity. Full article

Service continuity in power systems represents one of the key factors in designing the network architecture, in selecting the protection devices and in programming the maintenance operations. Standard strategies have to face a new issue represented by the possibility that intentional electromagnetic interference (IEMI) may occur. IEMI is defined as the “Intentional malicious generation of electromagnetic energy introducing power, noise or signals into electric and electronic systems, thus disrupting, confusing or damaging these systems”, and may affect the functionality of either power or telecommunications systems. Such hostile interferences may have different purposes: in the context of a war, for terroristic aims, or common criminal objective, e.g., requests for ransom. The focus of this work is on power substations, particularly on MV-LV installations, which often have limited surveillance and are located in proximity to easily accessible areas. The main issues are presented, and guidelines are provided for designing new substations or improving the immunity of installed apparatus, such as electronic protection devices, measurement instruments, and other tools equipping smart and traditional power grids. The challenges are put in evidence, and perspectives are provided with special reference to the possible evolution of interfering technologies. Full article

Fifth-generation (5G) and sixth-generation (6G) wireless communications aim to achieve significantly higher data speeds, remarkably low latency, and substantial improvements in the efficiency of base stations. With the rapid increase in the utilization of broadband data driven by Internet of Things (IoT) gadgets, smart home systems, autonomous vehicles, and virtual reality devices, 5G and 6G networks are set to overcome the limitations of earlier telecommunication technologies and serve as key enablers for future IoT applications. Anticipated as the primary infrastructure for delivering emerging services, 5G cellular networks introduce new requirements and challenges that complicate the achievement of desired objectives. This paper provides a comprehensive overview of machine learning (ML) methods and their application in 5G and 6G wireless networks, covering supervised, unsupervised, and reinforcement learning (RL) approaches. ML is set to play a central and important role in 6G systems for these wireless networks. Subsequently, this paper thoroughly explores a series of challenges within the domain of 5G and 6G networks and examines research opportunities for applying ML techniques to address these challenges. Full article