Dépôt numérique

Approaches for Adaptive Resource Allocation in Cognitive Radio Networks.

Asghari, Vahid Reza (2011). Approaches for Adaptive Resource Allocation in Cognitive Radio Networks. Thèse. Québec, Université du Québec, Institut national de la recherche scientifique, Doctorat en télécommunications, 246 p.

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Proposing efficient spectrum utilization techniques to alleviate spectrum congestion is one of the most important challenges in wireless communication technologies operating at specific spectrum bands. In fact, the growth of wireless application demands has caused the frequency allocation table for wireless services to become over congested. On the other hand, recent measurement studies have shown that the radio frequency spectrum in its current shape is inefficiently utilized. Hence, for the purpose of alleviating the long-standing problem of spectrum congestion, the federal communication commission (FCC) is actively revising the traditional spectrum allocation policies and moving towards the adoption of opportunistic spectrum-sharing techniques using cognitive radio. Cognitive radio (CR) is a technology that has the ability of sensing the environment in which it operates and adapting to its changes. For instance, through sensing, CR detects the portions of the spectrum that are un-occupied (also referred to as spectrum holes) at a specific location or time. One of the most efficient ways to identify spectrum holes is to sense the activity of the primary users operating within the secondary users' (cognitive user) range of communication. In this dissertation, we study different approaches for adaptive resource allocation in spectrum-sharing CR networks. In this context, we propose utilizing spectrum sensing information about the primary users' activity and secondary channel knowledge to adaptively adjust the secondary transmission parameters such as time, power and rate while adhering to the generated interference at the primary receivers. In this case, a proper resource management is needed so as to maximize the throughput performance of the secondary users and avoid performance degradation for the primary users. The existence and specification of such resource allocation are necessary issues and will be investigated in this dissertation for different operating scenarios. We also propose adopting cooperative relaying techniques in spectrum-sharing CR systems to more effectively and efficiently utilize the available transmission resources while adhering to the quality of service requirements of the primary (licensed) users of the shared spectrum band. In particular, while the moment generating function approach is commonly used to evaluate the performance analysis of cooperative relaying systems, we propose a unified framework which relies on the first-order statistics and convolutional methods to investigate the end-to-end performance of cooperative relaying spectrum-sharing systems. Furthermore, we quantify the advantages of utilizing relaying transmissions in spectrum-sharing CR networks for different operating scenarios and conditions.

Type de document: Thèse
Directeur de mémoire/thèse: Aïssa, Sonia
Mots-clés libres: radio; réseaux cognitifs; allocation; ressources; adaptatives; multi-utilisateurs; communications sans fil
Centre: Centre Énergie Matériaux Télécommunications
Date de dépôt: 22 janv. 2013 16:38
Dernière modification: 06 nov. 2015 18:48
URI: http://espace.inrs.ca/id/eprint/715

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