70 research outputs found
doi:10.1155/2007/25361 Research Article Performance Analysis of SSC Diversity Receivers over Correlated Ricean Fading Satellite Channels
No full textThis paper studies the performance of switch and stay combining (SSC) diversity receivers operating over correlated Ricean fading satellite channels. Using an infinite series representation for the bivariate Ricean probability density function (PDF), the PDF of the SSC output signal-to-noise ratio (SNR) is derived. Capitalizing on this PDF, analytical expressions for the corresponding cu-mulative distribution function (CDF), the moments of the output SNR, the moments generating function (MGF), and the average channel capacity (CC) are derived. Furthermore, by considering several families of modulated signals, analytical expressions for the average symbol error probability (ASEP) for the diversity receivers under consideration are obtained. The theoretical analy-sis is accompanied by representative performance evaluation results, including average output SNR (ASNR), amount of fading (AoF), outage probability (Pout), average bit error probability (ABEP), and average CC, which have been obtained by numerical techniques. The validity of some of these performance evaluation results has been verified by comparing them with previously known results obtained for uncorrelated Ricean fading channels. Copyright © 2007 P. S. Bithas and P. T. Mathiopoulos. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1
Performance analysis of a class of GSC receivers over nonidentical Weibull fading channels
No full textThe performance of a class of generalized-selection combining (GSC) receivers operating over independent but non-identically distributed Weibull fading channels is studied. We consider the case where the two branches with the largest instantaneous signal-to-noise ratio (SNR), from a total of L available, GSC(2, L) are selected. By introducing a novel property for the product of moments of ordered Weibull random variables, convenient closed form expressions for the moments of the GSC(2,L) output SNR are derived. Using these expressions, important performance criteria, such as average output SNR and amount of fading, are obtained in closed form. Furthermore, employing the Pade approximants theory and the moment-generating function approach, outage and bit-error rate performance are studied. An attempt is also made to identify the equivalency between the Weibull and the Rice fading channel, which is typically used to model the mo-bile satellite channel. We present various numerical performance evaluation results for different modulation formats and channel conditions. These results are complemented by equivalent computer simulated results which validate the accuracy of the proposed analysis
A systematic literature review on the role of UAV-enabled communications in advancing the UN’s sustainable development goals
No full textUnmanned Aerial Vehicles (UAVs), commonly known as drones, show great potential in advancing the United Nations (UN) Sustainable Development Goals (SDGs), a collection of 17 worldwide targets outlined by the United Nations (UN) to tackle diverse social, economic, and environmental issues and foster sustainable development by 2030. As per the Federal Aviation Administration (FAA), UAVs can significantly improve areas of sustainability like wildlife and wildfire monitoring, precision agriculture, as well as healthcare. Furthermore, drones with communication capabilities are seen as key elements of non-terrestrial networks, and as enabling technologies for future 6G communication networks. This systematic literature review focuses on the role of UAV-enabled communications to achieve the SDGs. Our study is based on a thorough selection and analysis of scientific articles. Initially, we performed a broad search across three major databases: IEEE Xplore, Web of Science, and Scopus, yielding a set of 10,499 papers. Following a strict selection methodology (Preferred Reporting Items for Systematic Review and Meta-Analysis - PRISMA), we narrowed this set down to 28 key journal articles. Our analysis highlights six global targets that greatly benefit from UAV-enabled aerial communication. In order of impact, these are: “Sustainable Cities and Communities,” where UAVs improve security and disaster management; “Life on Land,” where drones help with wildlife monitoring and reforestation; “Industry, Innovation, and Infrastructure,” where UAVs (Unmanned Aerial Vehicles) aid in infrastructure inspection; “No Hunger,” where drones improve agricultural practices; “‘Good Health and Wellbeing,” where UAVs assist with disease prediction and monitoring; and “Clean water and sanitation,”where drones play a crucial role in efficiently monitoring water quality and distribution. In summary, this paper offers a detailed look at the applications of UAVs in achieving the SDGs through aerial communications. By identifying areas of major impact and spotting gaps and weaknesses in current research, this review article aims to guide future research and policy-making in sustainable drone applications. Copyright © 2024 Gryech, Vinogradov, Saboor, Bithas, Mathiopoulos and Pollin
Operationalising Ecologically Sustainable Development at the Micro Level Pareto Optimality and the Preservation of Biologically Crucial Levels.
No full textThe concept of Ecologically Sustainable Economic Development (ESED) has led to relentlessly heated debate. Yet, it still remains without a clear operational framework. At the micro level where a multitude of projects and programmes are designed, the absence of operational principles has serious repercussions. In order to tackle this ineffectiveness, ESED may be viewed as a pattern of economic process and evolution that takes into account the constraints imposed by the natural environment. In effect, the economic process should ensure the preservation of the human race by maintaining the biological basis responsible for the healthy evolution of the race. In addition, economic development should not lead to Pareto suboptimal positions by precluding production potentials. Based on these principles, the present paper outlines an operational framework for ESED at the micro level of projects and programmes. Copyright © 2006 Inderscience Enterprises Ltd
Biological integrity as a prerequisite for sustainable development: A bioeconomic perspective
No full textDecisive conditions for an effective and efficient multi-model freight transport network in Europe
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