Página 1 dos resultados de 5514 itens digitais encontrados em 0.014 segundos

## Sensoriamento espectral baseado na detecção de energia para rádios cognitivos.; Spectrum sensing based on energy detection for cognitive radios.

Apaza Medina, Euler Edson
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Relevância na Pesquisa
46.29%

## Hardware implementation of a spectrum analyzer based in SDR; Implementação em hardware de um analisador de espectros baseado em SDR

Carreira, João Carlos da Silva
ENG
Relevância na Pesquisa
46.29%

## Arquiteturas eficientes para sensoriamento espectral e classificação automática de modulações usando características cicloestacionárias

Lima, Arthur Diego de Lira
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Elétrica; Automação e Sistemas; Engenharia de Computação; Telecomunicações Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Elétrica; Automação e Sistemas; Engenharia de Computação; Telecomunicações
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
46.27%
The increasing demand for high performance wireless communication systems has shown the inefficiency of the current model of fixed allocation of the radio spectrum. In this context, cognitive radio appears as a more efficient alternative, by providing opportunistic spectrum access, with the maximum bandwidth possible. To ensure these requirements, it is necessary that the transmitter identify opportunities for transmission and the receiver recognizes the parameters defined for the communication signal. The techniques that use cyclostationary analysis can be applied to problems in either spectrum sensing and modulation classification, even in low signal-to-noise ratio (SNR) environments. However, despite the robustness, one of the main disadvantages of cyclostationarity is the high computational cost for calculating its functions. This work proposes efficient architectures for obtaining cyclostationary features to be employed in either spectrum sensing and automatic modulation classification (AMC). In the context of spectrum sensing, a parallelized algorithm for extracting cyclostationary features of communication signals is presented. The performance of this features extractor parallelization is evaluated by speedup and parallel eficiency metrics. The architecture for spectrum sensing is analyzed for several configuration of false alarm probability...

## Cognitive ultra wideband radio spectrum sensing window length optimization algorithm

Zeng, Liaoyuan; McGrath, Sean; Liu, Guanghui
Tipo: info:eu-repo/semantics/article; all_ul_research; ul_published_reviewed
ENG
Relevância na Pesquisa
46.2%
peer-reviewed; A critical objective of cognitive radio (CR) system is to enhance the spectrum efficiency, and one of the key factors that can determine the spectrum efficiency is the system spectrum sensing performance with respect to sensing window length. For non-coherent detection-based sensing technique, the length of the sensing window required to meet the detection criteria is inversely proportional to the detected signal-to-noise ratio (SNR) of the primary users (PUs). This fact may result in an inadequate use of the white or gray space for the conventional CR system whose transmission and sensing window length are both fixed because a high detected PUs SNR can lead to an excessive long fixed sensing window which occupies the potential CR transmission opportunities while a low received PUs SNR can result in an insufficient sensing window length which degrades the CR detection criteria. In this paper, to improve the spectrum efficiency compared with the fixed sensing/transmission window length-based CR system, we propose an adaptive spectrum sensing window length optimization algorithm. We design the algorithm based on the ultra wideband (UWB) system which is an ideal candidate for the implementation of the CR technology. Based on the analysis of the CR-UWB’s spectrum sensing technique in terms of the factors such as spectrum efficiency...

## Managing the Radio Spectrum : Framework for Reform in Developing Countries

Wellenius, Björn; Neto, Isabel
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Relevância na Pesquisa
66.37%
Bringing management of the radio spectrum closer to markets is long overdue. The radio spectrum is a major component of the infrastructure that underpins the information society. Spectrum management, however, has not kept up with major changes in technology, business practice, and economic policy that have taken place worldwide during the last two decades. For many years traditional government administration of the spectrum worked reasonably well, but more recently it has led to growing technical and economic inefficiencies as well as obstacles to technological innovation. Two alternative approaches to spectrum management are being tried in several countries, one driven by the market (tradable spectrum rights) and another driven by technology innovation (spectrum commons). This paper discusses the basic features, advantages and limitations, scope of application, and requirements for implementation of these three approaches. The paper then discusses how these approaches can be made to work under conditions that typically prevail in developing countries...

## Radio Spectrum Management Development in India : A Framework for Strengthening Radio Spectrum Management and Policies

World Bank
Fonte: Washington, DC Publicador: Washington, DC
EN_US
Relevância na Pesquisa
66.37%
This report provides a detailed review of the current spectrum management regime in India; provides a perspective on best practice as may be applied in India and in addition provides a consideration of measures which could be taken to enhance spectrum management activities in India. The radio spectrum in India is a national resource, owned and managed by the Government. The authority for day-to-day spectrum management activities is vested Wireless Planning and Coordination (WPC) in New Delhi. Formal interfaces have been established with key spectrum user organizations, whose spectrum management staff may be found in other parts of India, remote from the capital city. The spectrum management regime has to date been strongly biased towards fulfilling the needs of the State and serving radio communications requirements funded by public sources. However, during the last 5 to 8 years a demanding private sector has made significant investments in the roll-out of new services and systems. The private sector (and indeed several segments of the public sector) is not entirely satisfied with the level of service provided by the spectrum management organization. This report performs the following functions: 1) it provides a detailed review of the current spectrum management regime in India; 2) it provides a commentary on best practice as may be applied in India in connection with each of the above areas; and 3) it provides a consideration of measures which could be taken to enhance spectrum management activities in India.

## The Radio Spectrum : Opportunities and Challenges for the Developing World

Wellenius, Björn; Neto, Isabel
Fonte: World Bank, Washington, DC; World Bank, Washington, DC Publicador: World Bank, Washington, DC; World Bank, Washington, DC
Relevância na Pesquisa
66.32%
The radio spectrum is a major component of the telecommunications infrastructure that underpins the information society. Spectrum management, however, has not kept up with major changes in technology, business practice, and economic policy during the past two decades. Traditional spectrum management practice is predicated on the spectrum being a limited resource that must be apportioned among uses and users by government administration. For many years this model worked well, but more recently the spectrum has come under pressure from rapid demand growth for wireless services and changing patterns of use. This has led to growing technical and economic inefficiencies, as well as obstacles to technological innovation. Two alternative approaches are being tried, one driven by the market (spectrum property rights) and another driven by technology innovation (commons). Practical solutions are evolving that combine some features of both. Wholesale replacement of current practice is unlikely, but the balance between administration, property rights, and commons is clearly shifting. Although the debate on spectrum management reform is mainly taking place in high-income countries, it is deeply relevant to developing countries as well.

Mochón, Asunción; Sáez, Yago; Gómez-Barroso, J.L.; Isasi, Pedro
Tipo: info:eu-repo/semantics/acceptedVersion; info:eu-repo/semantics/article Formato: application/pdf; text/plain
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The combinatorial clock-proxy auction is analyzed as a selling mechanism of a portion of the “digital dividend” in an European country. We assumed bidders with bounded rationality making their bidding decisions based on a system of recommendation that learns from the environment. The auction outcome when all bidders follow the proposed strategies was compared with the efficient outcome of the auction. Although significant differences were found in the seller’s income, no significant variations were found in the distribution of spectrum licenses among bidders.; This article has been financed by the Spanish research MCyT project MSTAR, Ref: TIN2008-06491-C04-03/TIN.

## Detección e identificación de señales para radio cognitiva

Cruz Barquero, María Ángeles de la
Tipo: info:eu-repo/semantics/bachelorThesis; info:eu-repo/semantics/masterThesis
SPA
Relevância na Pesquisa
46.19%

## Sound As a Dollar? The Propertization of Spectrum Resources and Implications for Non-Profit Community Radio in Guatemala

Henderson, Victoria L.
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 2204610 bytes; application/pdf
EN; EN
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## Estudi del desenvolupament i situació reglamentària de la ràdio cognitiva

Martínez Domingo, Esther; Rifà Pous, Helena
Tipo: Trabalho de Conclusão de Curso Formato: application/pdf