Spectrum Management

The rapid advancement of the Internet of Underwater Things (IoUT) necessitates robust, highcapacity communication systems that can operate efficiently in the challenging conditions of underwater environments. Optical Wireless Communication (OWC) systems, leveraging the advantages of high data rates and low latency, offer a compelling solution for IoUT. However, accurate modulation recognition in these systems remains a significant challenge due to the variable nature of underwater channels. This paper explores the application of Convolutional Neural Networks (CNNs) for modulation recognition in the OWC systems, focusing specifically on 64-QAM (Quadrature Amplitude Modulation) and 32-PSK (Phase Shift Keying). A CNN model-based approach is proposed to automatically extract and classify modulation features from received signals, demonstrating superior performance compared to traditional recognition methods. The model is applied to a dataset of 626 simulated images, categorized into two modulation types: 64QAM and 32PSK. Keras and TensoFlow frameworks are used to implement the model, the CNN undergoes hyperparameter tuning and data augmentation to optimize accuracy. The model's performance is assessed using a confusion matrix, along with precision-recall (PR) and receiver operating characteristic (ROC) curves. The experimental results show that the CNN achieves high accuracy in recognizing modulation types, with a testing accuracy of 100% and a testing loss rate of 1.82 × 10-6. Additionally, the model records a Precision, Recall, F1-score, and area under the ROC of 100%. The experiments reveal that the CNN model achieves high accuracy in differentiating between 64-QAM and 32-PSK under varying underwater conditions, highlighting its potential for enhancing IoUT communication reliability. INDEX TERMS Deep learning, convolutional neural networks (CNN), modulation recognition, 64-QAM, 32-PSK, optical wireless communications (OWC), Internet of Underwater Things (IoUT).

Starlink, SpaceX’s ambitious low-Earth orbit satellite internet constellation, secured regulatory approval and an operating license in Uganda in May 2026 after protracted negotiations and earlier restrictions. This milestone marks a significant turning point in Uganda’s digital landscape, promising to extend high-speed internet access to underserved communities, particularly in rural and hard‑to‑reach areas where traditional infrastructure has struggled to deliver reliable connectivity.
Beyond the immediate benefits of bridging the digital divide, Starlink’s entry into Uganda raises profound policy and governance questions. It compels regulators, policymakers, and stakeholders to grapple with issues of national sovereignty in telecommunications, the adequacy of existing taxation frameworks for cross‑border digital services, and compliance with Uganda’s Data Protection and Privacy Act laws. Equally pressing are concerns about consumer safeguards, affordability, and the potential disruption of local internet service providers.
At a broader level, this development intersects with Uganda’s economic ambitions. Enhanced connectivity could catalyze innovation, support E‑commerce, strengthen education and healthcare delivery, and attract foreign investment. Yet it also challenges the state to balance openness to global technology with the protection of domestic interests. The approval of Starlink is therefore not merely a technical or commercial decision, it is a strategic inflection point that will shape Uganda’s digital future, regulatory posture, and integration into the global knowledge economy.

Thesis title : Contribution to international space radiocommunications regulations
Abstract
The regulation of space radiocommunications appeared with the Administrative Radio Conference organized by the International Telecommunication Union (ITU) in 1959 in Geneva, two years after the launch of the first artificial satellite SPUTNIK in 1957. However, due to the rapid evolution of satellite technology, the ITU revises these regulations every three or four years during the World Radiocommunication Conferences (WRC). Thus, within the framework of this thesis, we expose in an exhaustive way the provisions and regulatory procedures enacted by the ITU and which govern the use of space radiocommunications in the world in order to avoid harmful interference in the radio spectrum and we also study the evolution of the regulation of space radiocommunications since 1959 to our days. In application of the regulatory procedures in force, within the framework of the contributions of this thesis, we proceed to the coordination and the notification of the GANDOUL-SEN-01-A earth station and to the study of the cases of interference between the INTELSAT-7 66°E and MARECS IND-1 geostationary satellites.
This thesis is a manuscript on the international regulation of space radiocommunications and is structured into two main parts : Part 1: Literature Review Part 2: Contributions
Keywords: Regulation, Radiocommunications, Telecommunications, Space, Satellite, World Conferences, Interference, ITU, coordination contour, carrier-to-interference ratio, noise temperature.

Traditionally, the frequency spectrum is licensed to users by government agencies in a fixed manner where the licensee has exclusive right to access the allocated band. However, with increasing demand for the spectrum and scarcity of vacant bands, a spectrum policy reform seems inevitable. Meanwhile, recent measurements suggest the possibility of sharing spectrum among different parties subject to interference-protection constraints. In order to enable access to an unused licensed spectrum, a secondary user has to monitor licensed bands and opportunistically transmit whenever no primary signal is detected. Spectrum-sharing between a primary licensee and a group of secondary users has been studied. The structure of an asymptotically optimum detector based on the measurements of all secondary users is derived and the effect of the quantisation error in such a system is evaluated. Also, it is shown that by using the proposed detector in a sequential detection structure, it is possible to shorten the decision time needed by the detector. The results show the superiority of the proposed detector to other schemes.

Intelligent Transport System (ITS) has emerged as the most probable technology for improved transport experience more so in environments with high vehicular density. Effective vehicular communication is however hindered by spectrum scarcity due to the already crowded licensed spectrum. This has led to the emergence of Cognitive Radio (CR) systems as a solution to the spectrum scarcity problem. A crucial component in CR is spectrum sensing. Various spectrum sensing techniques including Cyclostationary, Matched Filter, and Energy detection have been proposed and applied with varied outcomes. In this paper, the above mentioned detection techniques are discussed and an improved energy detection based cooperative spectrum sensing scheme is proposed for improved communication in vehicular ad hoc networks (VANET). The proposed scheme showed an improvement in the performance of a network which in turn could lead to more efficient utilization of spectrum.

This paper evaluates the large-scale channel parameters and the cell-edge coverage for various LTE-WiFi based, heterogeneous networks. Real world urban databases are incorporated into two separate 3D ray tracing software tools, specifically designed for the characterization of both microwave and millimeter (mm)-wave radio links. The study is performed for both LTE-800MHz and LTE-2.6GHz macro-cell configurations whereas it demonstrates the coverage enhancement attained by deploying 802.11n/ac/ad micro-cell structures. The significance of this study lies on the radio planning aspects of future heterogeneous networks.

This paper evaluates the large-scale channel parameters and the cell-edge coverage for various LTE-WiFi based, heterogeneous networks. Real world urban databases are incorporated into two separate 3D ray tracing software tools, specifically designed for the characterization of both microwave and millimeter (mm)-wave radio links. The study is performed for both LTE-800MHz and LTE-2.6GHz macro-cell configurations whereas it demonstrates the coverage enhancement attained by deploying 802.11n/ac/ad micro-cell structures. The significance of this study lies on the radio planning aspects of future heterogeneous networks.

This paper presents a detailed performance analysis of 5G N71 deployment in a live network environment, focusing on its impact on coverage enhancement, uplink performance, and overall network efficiency. Unlike mid-band 5G layers such as N78 and N40, which primarily address capacity requirements, the low-band N71 spectrum is deployed to improve coverage, particularly in indoor and cell-edge scenarios. The study was conducted across multiple sites using a 2×2 MIMO configuration, and performance evaluation was carried out using OSS-based key performance indicators (KPIs), drive test measurements, and user-experienced data including Ookla speed tests. The results indicate that N71 significantly improves coverage, with better signal propagation and deeper indoor penetration compared to higher frequency bands. In addition, uplink performance shows noticeable enhancement due to lower path loss and full-duplex operation, outperforming N40 and N78 in several scenarios. Traffic distribution analysis highlights the role of N71 in extending 5G service to areas previously dominated by LTE, thereby improving overall network accessibility. Despite limitations in carrier aggregation support and device compatibility, the deployment demonstrates stable network performance with no adverse impact on key KPIs. Overall, the findings confirm that N71 is an effective and scalable solution for enhancing 5G coverage and improving uplink performance in real-world network deployments.

This paper presents a comprehensive performance evaluation of 5G N40 integration utilizing AZNA in a nonbeamforming configuration within a live network environment. The study was conducted across multiple operational sites using a 4×4 MIMO setup to assess the impact of mid-band spectrum deployment on network capacity, traffic distribution, and overall user experience. Performance analysis was carried out using a combination of OSS-based key performance indicators (KPIs), detailed drive test measurements, and crowd-sourced Ookla speed test data, ensuring both network-level and end-user perspectives were captured. The results demonstrate a significant improvement in downlink throughput, with notable gains in both average and peak data rates after the activation of the N40 layer. Additionally, traffic analysis indicates a clear shift of user load from LTE to 5G, leading to improved load balancing and reduced congestion across existing layers. Drive test findings further confirm enhancements in radio conditions, including better signal quality, stable mobility performance, and consistent throughput across different coverage scenarios. Despite operating without beamforming, the AZNA-based deployment effectively improves spectral efficiency while maintaining network stability, with key KPIs such as accessibility, retainability, and availability remaining within acceptable limits. Overall, the study validates that N40 integration is a practical, scalable, and efficient solution for enhancing 5G network capacity and delivering improved user experience in high-demand environments

With the increasing demand for efficient video delivery over terrestrial broadcasting systems, selecting the appropriate video compression standard is crucial for optimizing bandwidth usage and maintaining high-quality transmissions. This study presents a comparative analysis of MPEG-4 (H.264/AVC) and HEVC (H.265) video compression standards in the context of Digital Video Broadcasting-Second Generation Terrestrial (DVB-T2) transmission. MPEG-4 has been widely adopted in previous broadcasting systems, while HEVC offers improved compression efficiency, making it a promising alternative for modern broadcasting applications. The research evaluates both codecs based on key performance metrics including compression ratio, video quality (measured via PSNR and SSIM), bitrate efficiency, and computational complexity. Test scenarios are developed using standard-definition and high-definition video content, encoded under similar transmission parameters suitable for DVB-T2. The results demonstrate that HEVC achieves up to 50% bitrate savings compared to MPEG-4 for equivalent video quality, thereby allowing more channels or higher quality content within the same bandwidth. However, HEVC's increased encoding complexity and hardware requirements are noted as potential limitations for deployment in existing infrastructure. This analysis provides critical insights into the trade-offs between legacy and next-generation codecs for DVB-T2 broadcasting, supporting broadcasters and policymakers in making informed decisions regarding system upgrades and spectrum management.

This paper proposes a formal framework for synthesizing multi-stage condition-based maintenance (CBM) decision logic for marine diesel monitoring systems. The design object is treated not as a single threshold or classifier output, but as an implementable decision logic with explicit stages of data-quality gating, thresholding, confirmation, fusion, and temporal filtering. Decision quality is evaluated using unconditional control-reliability indicators (CRIs) under a prescribed prior probability of rare abnormal events within a unified Monte Carlo verification protocol. Within a simplified Gaussian surrogate model, we compare baseline thresholding, repeated-measurement averaging, within-path confirmation, and measurement-level fusion. For the reported reference configuration, averaging five repeated measurements yields the largest reduction in the raw error criterion, "2 out of 3" confirmation provides a smaller but consistent improvement, and two-path multi-fidelity fusion is beneficial only after calibration toward the more informative path. The results show that, under rare abnormal events and limited measurement accuracy, decision quality is determined primarily by calibration of the multi-stage channel-level logic rather than by thresholding alone.

The current global move to switch from analogue to digital terrestrial television has opened up an opportunity for the re-allocation of valuable spectrum resources in VHF/UHF frequencies. In one way, spectrum bands once used for analogue TV broadcasting will be completely cleared, leaving a space for deploying new licensed wireless services, and in another way, digital terrestrial television technology geographically interleaves spectrum bands to avoid interference between neighboring stations, leaving a space for deploying new unlicensed wireless services. In this context, this paper studies spectrum availability in VHF/UHF frequencies, elaborates on their exploitation under a dynamic management approach and discusses their potential business strategies for introducing secondary systems/services within primary bands (i.e. TV bands). Following existing technological and scientific approaches for dynamic spectrum access, it presents a liberalised spectrum exploitation, based on "spectrum commons" and "spectrum markets" regimes rather than the custom "command and control" one.

Athina Bourdena (AEGEAN), George Kormentzas (AEGEAN), George Mastorakis (AEGEAN), Evangelos Pallis (AEGEAN), Paulo Marques (IT), Joseph Mwangoka (IT), Jonathan Rodriguez (IT), Jerzy Kubasik (PUT), Hanna Bogucka (PUT), Marcin Parzy (PUT), Georg Schuberth (IRT), Álvaro Gomes (PTIN), Helder Alves (PTIN)

India's spectrum management policies have transitioned from administrative allocation of spectrum to market-based assignment methods through auction, technological neutrality of licenses, and stronger ownership rights. Yet, the mobile service market in India has experienced financial distress, exit of operators, and growing concentration. 5G technologies will require wider access to spectrum resources, capital investment, and business innovation. This article examines how regulatory policies for availability and pricing of spectrum have impacted India's mobile markets. Based on a comparative analysis of international spectrum policy trends, it concludes that India's spectrum regime would require essential policy changes to meet the requirements of 5G.

Cognitive radio systems provide an intelligent solution to spectrum scarcity by dynamically accessing underutilized frequency bands licensed to primary users. Among various sensing techniques, energy detection (ED) is extensively adopted due to its inherent simplicity and minimal computational requirements, but suffers from poor performance at low signal-to-noise ratio (SNR) environments under channel impairments such as additive white gaussian noise (AWGN) and multipath fading. This paper proposes an enhanced spectrum sensing approach by integrating ED with entropy-based techniques, specifically Kapur and Renyi entropy measures. The proposed methods are evaluated under AWGN and various fading environments with binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) modulations. Simulation results demonstrate substantial improvements in detection performance. The results show that entropybased enhancements significantly improve the reliability of spectrum sensing in cognitive radio (CR) systems operating under challenging channel conditions. Among the fading models, the Nakagami channel causes the greatest degradation in detection probability, followed by the Rayleigh fading channel. ED with Renyi entropy improves Pd by 15-fold and 8-fold, compared to ED under Nakagami and Rayleigh channels respectively.

This paper presents a new fuzzified power allocation strategy that maximizes achievable secrecy rates while limiting overall transmit power. The fuzzy weight value obtained by determining the rules based on the weights obtained through the sequential update process. Also, it considers the outage probability of multi-source network-coded Device-2-Device (D2D) multicast with predetermined relays in the proposed fuzzified power allocation strategy. Multiple cooperative relays on each hop are also considered, to perform cooperative beamforming in the presence of multiple eavesdroppers. Enhancement in the secrecy rate us also assured along with power allocation. Numerical outcomes are presented to investigate the secrecy capacity obtained by the fuzzy based power allocation in multi-hop Decode & Forward (DF) relay networks and to confirm the enhancement of the proposed power allocation scheme by yielding the secrecy rate as 0.148. From the results, the energy efficiency of the proposed method based on Rayleigh h = 1 is 5.74, and it is 4.18%, and 1.92% better than the extant ICBD and NCDMC methods. In addition, the proposed work initially had a very low energy efficiency of 2.6864 (at the ns = 8) but eventually reached the highest energy efficiency of 7.194 as it approached the ns = 2.