The ability to accurately sense the surrounding wireless spectrum, without having any prior information about the type of signals present, is an important aspect for dynamic spectrum access and cognitive radio. Energy detection is one viable method, however its performance is limited at low SNR and must adhere to Nyquist sampling theorem. Compressive sensing has emerged as a potential method to recover wideband signals using sub-Nyquist sampling rates, under the presumption that the signals are sparse in a certain domain. In this study, the performance and some of the practical limitations of energy detection and compressive sensing are compared via simulation, and also implementation using the Universal Software Radio Peripheral (USRP) software defined radio (SDR) platform. The usefulness and simplicity of the USRP and GNU Radio software toolkit for simulation and experimentation, as well as some other application areas of compressive sensing and SDR, is also discussed.

Thesis (Masters Diploma( Technology)) --Cape Technikon, Cape Town, 1989 / Soekor's exploration programme has moved totally offshore and expanded greatly in the past few years. Use of computers necessitated the exchange of data between offshore and land installations. At the same time the exploration programme is moving further offshore While the coastal. stations of the Post & Telecommunications can not handle the volume of traffic that the oil drills present nor the data modes. A study of the transmission requirements revealed that a minimum of one voice channel per drill must be available at all times, While Some 20M byte of data per oil drill per year will be transmitted. Facsimile will be needed at times, also as a back-up for the data systems. A study of publications revealed that only five of the eleven methods studied where viable, namely VHF-EM, satellite, HF-telephony, HF-teleprinter and HF-data. These possibilities as well as their practical implementation were studied in depth. The effect of the atmospheric conditions on the propagation of VHF-signals around the coastline was studied and 17 sites identified and evaluated from the mouth of the Orange River to Port Elizabeth in respect of coverage, accessibility, facilities and cost. INMARSAT facilities and costs were evaluated as well as HF-systems. Finally a system was designed consisting of HF-telephony, separate "packet" HF radio data system, satellite telephony back-up and satellite high speed data as well as a limited VHF system. The entire system is complemented by marine telephony and telegraphy equipment. On-going system guidance in the form of propagation predictions is provided. Some existing equipment was used, While R950 000 has been spent to date on additional equipment.

El presente artículo presenta la historia de los años iniciales de Radio Cutivalú, importante emisora de Piura, que ha desarrollado en sus casi tres décadas de existencia diversas acciones a favor de su comunidad. El acercamiento a este recuento histórico es a partir de los relatos y testimonios dealgunos de los protagonistas que llevaron adelanteel proyecto de la radio y su implementación. De esta forma, se recorren las propuestas iniciales, sus temáticas, sus estrategias, sus logros y los problemas que debieron enfrentar. Es un relato desde la subjetividad de los recuerdos y desde la reconstrucción de una historia colectiva apartir de aquellos que la vivieron.

The 1980s and 1990s saw two major changes in the political economy of the media and the world economy at large: technological advancement and transfer and privatisation. There were significant shifts in media industries: newspapers, broadcasting, cinema and telecommunications when governments begun re-regulating their air waves so as to permit private satellite transmission via both encryption and free-to-air, in addition to public service and private channels. In most societies where these changes have taken place, public service broadcasting has been threatened by the rapid rise of commercial institutions, resulting in stiff competition for audiences. This study set out to determine the extent to which commercialisation, in the era of liberalisation and commercialisation of media services in Uganda, has affected Radio Uganda’s programming. Using a combination of qualitative and quantitative methods of investigation, I have established that while Radio Uganda still maintains certain public service principles and values, programming policy has increasingly been changed by commercial considerations. This is shown by the recent rise of commercial programmes and a fall in education and developmental programmes. Limitations of finance and other resources have compromised the roles and character of public service radio programming. The majority of programmes currently on Radio Uganda are evidently geared to attract advertisers rather than serve the public interest. The study recommends, among other measures, that the licence fee be developed as a source of revenue for Radio Uganda. Secondly, government should inject more funding into public service broadcasting institutions to supplement other sources of income, before granting them autonomy. Thirdly, while advertising and sponsorship brings in a considerable amount of revenue, it should not take a central place that undermines the listener’s interest in radio programming. The Broadcasting Council should therefore map out solid policies that will systematically guide Radio Uganda in its programming in the new order.

[Summary] Chapter I . The general characteristics of solar radiation at metre wavelengths are described, with reference to data published in the literature. A brief description of some aspects of solar physics relevant to the study of solar noise is given, and the literature relating to the correlation of radio effects with solar disturbances is reviewed. Chapter II. A concise description of the apparatus constructed for the continuous recording of the flux density of solar radio noise at a frequency of 300 Mc/s is given, with some mention of difficulties experienced, and how these were overcome. Full circuit diagrams of electronic apparatus, and illustrative photographs, are supplied. Chapter III. The development of theories of the origin and propagation of solar noise radiation is historically reviewed and the success of each theory in explaining or predicting observed phenomena, is assessed. A working model is chosen from among these theories, and reasons for its adoption are given. Chapter IV. Observations made by the author of solar radiation at a frequency of 300 Mc/s are described, together with a description of the objects and methods, of analysis of the records. Chapter V. Phenomena observed by the author are compared with those observed by other workers. It is concluded that storm bursts are caused by transients similar to those producing Type II and Type ITI bursts, and a model for the production of storm bursts is tentatively suggested. Chapter VI. Suggestions for further research, including suggestions for methods of testing the author's conclusions, are made.

The purpose of this treatise is a development of a suitable model for a community radio station which would lead to operational effectiveness and ensure sustainability. The treatise has three phases namely a theoretical phase, a narration phase and an integration phase. Firstly, in the theoretical phase the research study investigates what the literature review reveals about community radio stations and business models. This treatise argues that a total dependency of community radio stations on donor funding leads to operational ineffectiveness which threatens their sustainability. The treatise also argues that a business model could be adapted for a community radio station by identifying the business issues which the literature review revealed, and use these to deconstruct a theoretical business model. Secondly, in the narrative phase the research study investigates the important business issues for a selected community radio station. The treatise argues the board and management of this selected community radio station revealed additional business issues of operations and gave different ratings to business issues which are important in their operations. Thirdly, in the integration phase, the theoretical model deconstructed in the theoretical phase, was revised by including additional business issues of operations revealed in the narrative phase. The research study concludes that this revised model is a suitable business model for a community radio station and can lead to operational effectiveness and ensure sustainability.

Thesis (M.A.(Media Studies)) --University of the North, 2002 / This research report looks at Radio Turf as a radio station serving the university community as well af the neighbouring communities. It seeks to establish whether Radio Turf is indeed an empowering tool to the community it serves, looking at language usage, skills development, promotion of local music, gender issues and education. It further seeks to establish whether it is indeed a community radio station in the true sense of the word. The research report lso looks at ways and means of improving community radio stations in general as a way of empowering the communities they serve through participation and involvement. The report could be of assistance to the radio station in as far as knowing its weaknesses and strong points as a way of improving its service to the community it serves

Thesis (M.S.)--Boston University. PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.

This thesis presents results of average and impulsive noise measurements inside five office buildings and retail stores. Measurements were made at 918 MHz, 2.44 GHz, and 4.0 GHz using a superheterodyne receiver with 70 dB dynamic range and a 3-dB RF bandwidth of 40 MHz. Omni-directional and directional antennas were used to investigate the characteristics and sources of radio frequency noise in indoor channels. Statistical analyses of the measured data are presented in the form of amplitude probability distributions, pulse duration distributions, pulse spacing distributions, and noise factor distributions. Simple mathematical models of these statistical characterizations are also presented. The measurements and analyses indicate devices with electromechanical switches (copy machines, microwave ovens, printers, and electric motors) are principal sources of impulsive noise in retail and office environments. The 918 MHz band was consistently the worst band throughout the measurement campaign. This is attributed to higher path losses at 2.44 GHz and 4.0 GHz, and to adjacent and cochannel interference from users near the 902-928 ISM band. Pulse duration statistics indicate that no significant differences exist between impulse durations in the measured bands. This suggests that impulsive noise inside buildings is very wideband, and that pulse durations are directly a function of the receIver bandwidth. Pulse spacing statistics also indicate that intervals between consecutive impulses are similar in each frequency band. This thesis developed a computer simulation algorithm to create sequences of impulsive noise events which have statistical distributions similar to measured data. The statistical results for simulated impulsive noise are compared to measured distributions to illustrate the accuracy of the simulation algorithm. / Master of Science

Pour supporter l’évolution constante des standards de communication numérique, du GSM vers la 5G, les équipements de communication doivent continuellement s’adapter. Face à l’utilisation croissante de l’internet, on assiste à une explosion du trafic de données, ce qui augmente la consommation d'énergie des appareils de communication sans fil et conduit donc à un impact significatif sur les émissions mondiales de CO2. De plus en plus de recherches se sont concentrées sur l'efficacité énergétique de la communication sans fil. La radio Intelligente, ou Cognitive Radio (CR), est considérée comme une technologie pertinente pour les communications radio vertes en raison de sa capacité à adapter son comportement à son environnement. Sur la base de métriques fournissant suffisamment d'informations sur l'état de fonctionnement du système, une décision optimale peut être effectuée en vue d'une action de reconfiguration, dans le but de réduire au minimum la dissipation d'énergie tout en ne compromettant pas les performances. Par conséquent, tout équipement intelligent doit disposer d’une architecture de gestion de la reconfiguration. Nous avons retenu l’architecture HDCRAM (Hierarchical and Distributed Cognitive Radio Architecture Management), développée dans notre équipe, et nous l’avons déployée sur des plates-formes hétérogènes. L'un des objectifs est d'améliorer l'efficacité énergétique par la mise en œuvre de l’architecture HDCRAM. Nous l’avons appliquée à un système OFDM simplifié pour illustrer comment HDCRAM permet de gérer efficacement le système et son adaptation à un environnement évolutif. / As the digital communication systems evolve from GSM and now toward 5G, the supported standards are also growing. The desired communication equipments are required to support different standards in a single device at the same time. And more and more wireless Internet services have been being provided resulting in the explosive growth in data traffic, which increase the energy consumption of the communication devices thus leads to significant impact on global CO2 emission. More and more researches have focused on the energy efficiency of wireless communication. Cognitive Radio (CR) has been considered as an enabling technology for green radio communications due to its ability to adapt its behavior to the changing environment. In order to efficiently manage the sensing information and the reconfiguration of a cognitive equipment, it is essential, first of all, to gather the necessary metrics so as to provide enough information about the operating condition thus helping decision making. Then, on the basis of the metrics obtained, an optimal decision can be made and is followed by a reconfiguration action, whose aim is to minimize the power dissipation while not compromising on performance. Therefore, a management architecture is necessary to be added into the cognitive equipment acting as a glue to realize the CR capabilities. We introduce a management architecture, namely Hierarchical and Distributed Cognitive Radio Architecture Management (HDCRAM), which has been proposed for CR management by our team. This work focuses on the implementation of HDCRAM on heterogeneous platforms. One of the objectives is to improve the energy efficiency by the management of HDCRAM. And an example of a simplified OFDM system is used to explain how HDCRAM works to efficiently manage the system to adapt to the changing environment.