A thesis submitted in fulfilment of the requirements for the degree of Master of Arts, in ICT Policy and Regulation, University of the Witwatersrand, 2016 / There is a common opinion among researchers and experts that efficient management of radio spectrum plays a vital role in ensuring universal access to telecommunications services. The objective of this study was to identify radio spectrum reforms and their associated effects on market liberalisation. It was postulated that appropriate radio spectrum reforms would be catalysts for market liberalisation. The evolution of command-and-control approaches in relation to market-based approaches was assessed. The research involved literature critique, review of policies as that relates to history of radio spectrum management in South Africa and across the world, and radio spectrum regulations analysis in South Africa. Interviews of radio spectrum industry experts and documents study of the evolution of telecommunications regulatory environment with respect to radio spectrum management and market liberalisation were also used as main sources of research. The purpose of the literature critique, review of policies, regulations and documents was to identify hints of radio spectrum reforms and measure qualitatively the extent of market liberalisation. While interviews of radio spectrum industry experts were used to ascertain industry response to strides made as far as radio spectrum and market liberalisation in South Africa. It was observed that initially, in most parts of the world and in South Africa, market liberalisation progressed quickly despite appreciable correlation with radio spectrum reforms. Early radio spectrum reforms, such as the establishment of an independent regulator of the industry and radio spectrum, had contributed to some level of market liberalisation with creation of oligopolistic telecommunication market, and had increased to radio spectrum by Vodacom, MTN and Cell C having access to both 900 MHz and 1800 MHz bands. However, perpetual practise of command-and-control, an efficient radio spectrum management encouraged hoarding. The literature review and interview provided seven main contributions of reforms in the form of strides. These strides formed the basis for the research framework: 1) establishment of an independent regulator of the industry and radio spectrum, 2) increased access to radio spectrum, 3) service and technology neutrality on radio spectrum, 4) essential facilities to enable sharing, 5) market-based approaches radio spectrum pricing: AIP, 6) service-based competition versus infrastructure-based competition, and 7) non-rival, non-exclusive usage of radio spectrum. The conclusion is that increasing access to radio spectrum and the independent regulator were not primary determinants of market liberalisation. An analytic framework has been used to show that market liberalisation reached a plateau phase, with a few incumbents becoming dominant and creating an oligopolistic market structure. It is at this point that further market liberalisation could be stimulated by additional radio spectrum reforms. The command-and-control approach remains the main bottleneck source for access and efficiency in radio spectrum management, which encourages rival and exclusive use of radio spectrum. It has been observed that market-based radio spectrum reforms have also entrenched rivalry and exclusivity in the use of radio spectrum. Radio spectrum reforms that encourage non-rivalry and non-exclusivity, such as open-access to radio spectrum, are highly recommended in this research. / GR2016

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Radio spectrum is a vital national asset; proper management of this finite resource is essential to the operation and development of telecommunications, radio-navigation, radio astronomy, and passive remote sensing services. To maximize the utility of the radio spectrum, knowledge of its current usage is beneficial. As a result, several spectrum studies have been conducted in urban Atlanta, suburban Atlanta, and rural North Carolina. These studies improve upon past spectrum studies by resolving spectrum usage by nearly all its possible parameters: frequency, time, polarization, azimuth, and location type. The continuous frequency range from 400MHz to 7.2 GHz was measured with a custom-designed system. More than 8 billion spectrum measurements were taken over several months of observation. A multi-parameter spectrum usage detection method was developed and analyzed with data from the spectrum studies. This method was designed to exploit all the characteristics of spectral information that was available from the spectrum studies. Analysis of the spectrum studies showed significant levels of underuse. The level of spectrum usage in time and azimuthal space was determined to be only 6.5 % for the urban Atlanta, 5.3 % for suburban Atlanta, and 0.8 % for the rural North Carolina spectrum studies. Most of the frequencies measured never experienced usage. Interference was detected in several protected radio astronomy and sensitive radio navigation bands. A cognitive radio network architecture to share spectrum with fixed microwave systems was developed. The architecture uses a broker-based sharing method to control spectrum access and investigate interference issues.

Orientador: Luiz Carlos Kretly / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-08T18:48:25Z (GMT). No. of bitstreams: 1 Portelinha_FranciscoMartins_D.pdf: 24786076 bytes, checksum: 9371c9850eefc768ce24e777299b0788 (MD5) Previous issue date: 2007 / Resumo: Em freqüênciasabaixode 3 GHz, ocorreuma demandade bandas no espectrode freqüência, devido à expansãodas redes de comunicaçõessem fio, principalmentepara aplicações outdoor. Estudosmostram que há grandes lacunas no espectrode freqüência até a faixa de 3 GHz. O modelo de alocação do espetrode freqüência,já ultrapassado, precisa ser reformuladopara uso destas lacunas.A utilização do espectro deve sair do modelo estático,para o modelodinâmico.Rádioscognitivose redes de rádios cognitivos surgem como opção tecnológica para uso deste novo modelo. Apresentamos uma arquitetura inovadorapara a implementaçãode rádios cognitivos,baseadosnos modelos computacionais de: rádios definidos por software,agentes e frameworks.Um estudo de caso, para rádio cognitivo nível 2, é apresentado para uso não licenciado no espectro nas faixas licenciadas para TV. Um algoritmo inovador, para detecção da disponibilidade de canais, é desenvolvido utilizando redes neurais / Abstract: In frequencies lower than 3 GHz, a demand occurs out of the frequency spectrum due to the expansion of the wireless communication network, mainly for outdoor applications. Studies show that, there are great gaps of the frequency spectrum in the bands up to 3 GHz. The allocation model of the frequency spectrum needs reformulatiQn for the use of these gaps. This utilization must come from, the change of a static model to a dynamic one. Cognitive radio and cognitive radio networks rise as a technological option for the use of the new model. We introduce and an innovatory architecture for the implementation of cognitive radios, based on the computational models of: software defined radio, agents and frameworks. A case study, for cognitive radio leveI 2, is introduced for use in licensed TV bands. A new algorithm is developed to detect available channel / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

In wireless communication systems, one of the most important resources being focused on all the researchers is spectrum. A cognitive radio (CR) system is one of the efficient ways to access the radio spectrum opportunistically, and efficiently use the available underutilized licensed spectrum. Spectrum utilization can be significantly enhanced by developing more applications with adopting CR technology. CR systems are implemented using a radio technology called software-defined radios (SDR). SDR provides a flexible and cost-effective solution to fulfil the requirements of end users. We can see a lot of innovations in Internet of Things (IoT) and increasing number of smart devices. Hence, a CR system application involving an IoT device is studied in this thesis. Opportunistic spectrum access involves two tasks of CR system: spectrum sensing and dynamic spectrum access. The functioning of the CR system is rest upon the spectrum sensing. There are different spectrum sensing techniques used to detect the spectrum holes and a few of them are discussed here in this thesis. The simplest and easiest to implement energy detection spectrum sensing technique is used here to implement the CR system. Dynamic spectrum access involves different models and strategies to access the spectrum. Amongst the available models, an interweave model is more challenging and is used in this thesis. Interweave model needs effective spectrum sensing before accessing the spectrum opportunistically. The system designed and simulated in this thesis is capable of transmitting an output from an IoT device using USRP and GNU radio through accessing the radio spectrum opportunistically.