Cette recherche présente une analyse historique de la naissance et de l’évolution des radios libres en Italie et en France à partir du début des années soixante-dix jusqu’à la fin des années quatre-vingt au XXe siècle. Le caractère comparatif de la recherche illustre les similitudes et les divergences soit des processus sociaux-historiques, soit des différents systèmes politiques, qui ont déterminé l’apparition et l’évolution de ces formes de communication en dehors du monopole d’Etat et leur intégration à l’intérieur de systèmes médiatiques spécifiques, aux réalités nationales singulières. L’étude s’insère dans l’histoire des médias des deux Pays. Le parcours des radios libres montre de quelle façon on est passé des revendications originelles de la prise de parole libre, d’une communication décentrée, de la réalisation de médias démocratiques, à l’affirmation dans les années quatre-vingt du modèle de la radio commerciale, influencé par la domination de la télévision et de la publicité. L’évolution des radios libres contribue à redéfinir le paysage audiovisuel en décrétant la fin du monopole public du service audiovisuel. Les radios libres, en exprimant le point de vue de groupes politiques, culturels, religieux et de communautés locales, ont représenté un moment d’ouverture et de démocratisation du secteur des médias et d’élargissement de l’espace de la sphère publique. Même si ces objectifs pendant les années quatre-vingt ont été en partie remplacés par l’affirmation des radios à vocation musicale, à cause de situations politique, sociale et économique différentes, l’expérience des radios communautaires, favorisant une communication de proximité sans but lucratif, ont constitué les héritières directes de la période des radios libres. Bien qu’elles n’occupent qu’une place réduite dans les systèmes médiatiques de l’Italie et de la France, ces radios ont démontré l’importance sociale des moyens de communications alternatifs et locaux, au niveau soit des contenus, soit de l’organisation radiophonique, en anticipant en partie des formes d’interactivité qui se développeront dans les décennies suivantes avec la naissance des webradios. / The thesis presents an historical analysis of the birth and evolution of free radios in Italy and France between the beginning of ‘70s (seventies) and the end of ‘80s (eighties) of the 20th century. The comparative character of the study highlights the similarities and divergences of both the historical-social processes and the various political systems which determined the emergence and transformation of such from-the-ground means of communication, out of the central monopoly of the State as well as their insertion in the proper frame of national media. The study finds its place in the historical context of the two countries. The route of free radios shows how one passed from the original claim of ‘taking-the-word’, of off-centred communication, of realization of democratic media, to the affirmation in the Eighties of the model of commercial radio, influenced by the centrality of the television and the commercials. The evolution of free radios contributes to redefine the audio-visual landscape of the two countries, causing the end of the public monopoly of the radio and TV broadcast. Free radios, expressing the point-of-new of political, cultural and religious groups of local communities, represented a moment of opening and democratization of the media sector and of widening of spaces of the public sphere. Although these objectives in the Eighties, thanks also to a changed political, social and economic frame, were substituted by the affirmation of the music radios, communitary radios, which favored non-profit forms of communication of proximity, constituted the direct heir of free radios. Despite they occupied a reduced space in the media system of the two countries, they proved the social importance of alternative and local means of communication, with respect to the radiophonic contents and the organization, partially anticipating certain features of interactivity which will be recovered years later with the rise of the web-radios.

Extrait de: Doctoral dissertation--Faculty of social sciences--Rome--Pontifical Gregorian university, 2006. / Bibliogr. p. 60-72.

Current wireless communications are confronted with two significant problems with regard to spectrum use --- spectrum scarcity and deployment difficulties. It is widely believed that Software Defined Radios (SDRs) and Cognitive Radios (CRs) are the key enabling technologies to address these problems. The reconfigurability of SDRs combined with the decoupling of policies and the platform in policy-based radios poses a new technical problem --- viz, enforcing policy conformance. Each DARPA XG radio is equipped with a set of policy conformance components (PCCs) which are responsible for ensuring that the radio is policy-conformant and does not cause harmful interference. The Policy Reasoner (PR) is the inference component of the PCCs whereas the Policy Enforcer (PE) performs enforcement. DARPA's XG program prescribes the Software Communications Architecture (SCA) as the model for SDR/CR architectures. Distributed processing is a fundamental aspect of the SCA, and it uses the Common Object Resource Broker Architecture (CORBA). It is reasonable to assume that some of the SDRs will be implemented as distributed systems, irrelevant of whether they are SCA compliant devices. It is thus obvious that middleware has to be secured for complete security. This thesis enumerates the requirements of an "ideal" PE. We have described the design and implementation of two possible implementations, which can fulfill some of these requirements. The PE can function similar to a firewall, and be at the very boundary of software and hardware components. The PE can also be implemented as a "man-in-the-middle" between the System Strategy Reasoner and the transmission hardware. We further describe a novel method of providing cache coherency for a cache-based PE. We also perform an in-depth analysis of the security requirements in a distributed implementation of a policy-based radio. To this end, we describe the design and implementation of such a system using CORBA middleware. We identify potential vulnerabilities due to the use of CORBA, and describe countermeasures for them. We compare the performance of transport and security mechanisms of two commercial, off-the-shelf (COTS) Object Request Brokers. We show that the magnitude of performance degradation can be reduced by the use of a cleverly selected combination of transport and security mechanisms. / Master of Science

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Software radio is a new concept emerging in military communication and commercial wireless communication systems. Its kernel idea is to give a support with rapid building the flexible, modular, multiband and multimode wireless systems. This paper aims at programmable detection module in software radio application. It uses adaptive software to realize the detection function, this will greatly enhance the wireless receivers’ flexibility and intelligent process. From the simulation results of MPSK adaptive detection software, it can be concluded that adaptive software makes the system easy to realize detection function for various applications.

In an interference network, multiple transmitters communicate with multiple receivers using the same communication channel. The capacity region of an interference network is defined as the set of data rates that can be simultaneously achieved by the users of the network. One of the most important example of an interference network is the wireless network, where the communication channel is the wireless channel. Wireless interference networks are known to be interference limited rather than noise limited since the interference power level at the receivers (caused by other user's transmissions) is much higher than the noise power level. Most wireless communication systems deployed today employ transmission strategies where the interfering signals are treated in the same manner as thermal noise. Such strategies are known to be suboptimal (in terms of achieving higher data rates), because the interfering signals generated by other transmitters have a structure to them that is very different from that of random thermal noise. Hence, there is a need to design transmission strategies that exploit this structure of the interfering signals to achieve higher data rates. However, determining optimal strategies for mitigating interference has been a long standing open problem. In fact, even for the simplest interference network with just two users, the capacity region is unknown. In this dissertation, we will investigate the capacity region of several models of interference channels. We will derive limits on achievable data rates and design effective transmission strategies that come close to achieving the limits. We will investigate two kinds of networks - "small" (usually characterized by two transmitters and two receivers) and "large" where the number of users is large. / text

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 73-75).

El presente artículo aborda el rol de las radios comunitarias en la promoción de la ciudadanía social y política en comunidades rurales andinas. Explora la manera cómo determinados enfoques y formatos radiofónicos participativos podrían generar una toma de conciencia y reforzar aprendizajes relacionados con el ejercicio de derechos ciudadanos especialmente en comunidades andinas. Y sostiene que la música y los relatos orales, recogidos en diversos formatos radiofónicos, contribuirían al fortalecimiento de las identidades locales y el sentido de pertenencia en las comunidades

It is the purpose of this study to make an investigation of the uses made of the radio in the seventh grade in the schools in Hill County, in an endeavor to make available to administrators and teachers the possibilities of radio as an educational medium, and also to suggest additional techniques of utilization.

In this thesis, we benchmark the Cognitive Radios Test System version 2.0 (CRTSv.2) to analyze its software performance with respect to its internal structure and design choices. With the help of system monitoring and profiling tools, CRTSv.2 is tested to quantitatively evaluate its features and understand its shortcomings. With the help of GNU Radio, a popular, easy-to-use software radios framework, we ascertain that CRTSv.2 has a low memory footprint, fewer dependencies and overall, is a lightweight framework that can potentially be used for real-time signal processing. Several open-source measurement tools such as valgrind, perf, top, etc. are used to evaluate the CPU utilization, memory footprint and to postulate the origins of latencies. Based on our evaluation, we observe that CRTSv.2 shows a CPU utilization of approximately 9% whereas GNU Radio is 59%. CRTSv.2 has lower heap memory consumption of approximately 3MB to GNU Radio's 25MB. This study establishes a methodology to evaluate the performance of two SDR frameworks systematically and quantitatively. / Master of Science / When picking the best person for the job, we rely on the person's performance in past projects of a similar nature. The same can be said for software. Software radios provide the capability to perform signal processing functions in software, making them prime candidates towards solving modern problems such as spectrum scarcity, internet-of-things(IoT) adoption, vehicle-to-vehicle communication etc. In order to operate and configure software radios, software frameworks are provided that let the user make changes to the waveform, perform signal processing and data management. In this thesis, we consider two such frameworks,GNU Radio and CRTSv.2. A software performance evaluation is conducted to assess framework overheads contributing to operation of an orthogonal frequency-division multiplexing (OFDM) digital modulation scheme. This provides a quantitative analysis of a signals-specific use case which can be used by researchers to evaluate the optimal framework for research. This analysis can be generalized for different signal processing capabilities by understanding the total framework overhead removed from signal processing costs.

DARPA's neXt Generation (XG) communication program proposes the use of Dynamic Spectrum Access (DSA) wherein intelligent radios can realize opportunistic usage of frequency bands by identifying the under-utilized spectrum and reasoning about it. Implementing such a flexible scheme requires changes in the current static spectrum management approach. As a result, declarative spectrum management through policy-based dynamic spectrum access has garnered significant attention recently. Policy-based dynamic spectrum access decouples the Spectrum Access Policies and Policy Processing Components from the Radio Platform. The Policies define conditions under which the radios are allowed to transmit in terms of frequencies used, geographic locations, time etc. The Policy Processing Components include a reasoning engine called the Policy Reasoner, which is responsible for enforcing these policies. This thesis describes the design and implementation of a novel policy reasoner called Bi- nary Decision Diagram based Reasoner for processing Spectrum Access Policies (BRESAP). BRESAP processes spectrum policies efficiently by reframing the policy reasoning problem as a graph based Boolean function manipulation problem. BRESAP uses Binary Decision Diagrams (BDDs) to represent, analyze and process the policies. It uses a set of efficient graph-theoretic algorithms to merge these policies into a single meta-policy and compute opportunity constraints. Our policy reasoner has the capability to respond to invalid and under-specified transmission requests sent by the System Strategy Reasoner (SSR). In case of invalid or under-specified transmission requests, BRESAP returns a set of opportunity constraints which inform the SSR of the changes needed to the transmission parameters in order to make them conform to the policies. We also propose three algorithms for computing the opportunity constraints. The complexity of the first algorithm is proportional to the number of variables in the metapolicy BDD, while the complexities of the second and third algorithms are proportional to sum of number of variables and the size (i.e., number of nodes) of the meta-policy BDD. / Master of Science