Age of Information and Energy Efficiency in Communication Networks

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dc.contributor.advisorEphremides, Anthonyen_US
dc.contributor.authorDutra da Costa, Maiceen_US
dc.contributor.departmentElectrical Engineeringen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2015-09-18T05:55:18Z
dc.date.available2015-09-18T05:55:18Z
dc.date.issued2015en_US
dc.description.abstractThis dissertation focuses on two important aspects of communication systems, namely energy efficiency and age of information. Both aspects have received much less attention than traditional performance metrics, such as throughput and delay. The need to improve the energy efficiency in communication networks is apparent, given the high demand for power consuming applications to be implemented in devices with limited energy supplies. Additionally, improvements in energy efficiency are encouraged by possible reductions in network operation costs, and by the increasing awareness of the environmental impact caused by the information and communication technologies. In this dissertation, energy efficiency is studied in the context of a cognitive wireless network, in which users have different priorities to access the network resources, possibly interfering and cooperating among themselves. A new parametrization is proposed to characterize performance trade-offs associated with energy efficiency for non-cooperative and cooperative network models. Additionally, a game theoretic model is proposed to study resource allocation in a cooperative cognitive network, accounting for energy efficiency in the utility functions. Age of information is a relatively new concept, which aims to characterize the timeliness of information. It is relevant to any system concerned with timeliness of information, and particularly relevant when information is used to make decisions, but the value of the information is degraded with time. This is the case in many applications of communications and control systems. In this dissertation, the age of information is first investigated for status update communication systems. The status updates are samples of a random process under observation, transmitted as packets, which also contain the time stamp to identify when the sample was generated. The age of information at the destination node is the time elapsed since the last received update was generated. The status update systems are modeled using queuing theory. We propose models for status update systems capable of managing the packets before transmission, aiming to avoid wasting network resources with the transmission of stale information. In addition to characterizing the average age, we propose a new metric, called peak age, which provides information about the maximum value of the age, achieved immediately before receiving an update. We also propose a new framework, based on the concept of age of information, to analyze the effect of outdated Channel State Information (CSI) on the performance of a communication link in which the source node acquires the CSI through periodic feedback from the destination node. The proposed framework is suitable to analyze the trade-off between performance and timeliness of the CSI, which is a fundamental step to design efficient adaptation functions and feedback protocols.en_US
dc.identifierhttps://doi.org/10.13016/M2K64H
dc.identifier.urihttp://hdl.handle.net/1903/17059
dc.language.isoenen_US
dc.subject.pqcontrolledElectrical engineeringen_US
dc.subject.pqcontrolledInformation technologyen_US
dc.subject.pqcontrolledEngineeringen_US
dc.subject.pquncontrolledAge of Informationen_US
dc.subject.pquncontrolledCognitive Networksen_US
dc.subject.pquncontrolledCommunication Networksen_US
dc.subject.pquncontrolledEnergy Efficiencyen_US
dc.subject.pquncontrolledGame Theoryen_US
dc.subject.pquncontrolledQueuing Theoryen_US
dc.titleAge of Information and Energy Efficiency in Communication Networksen_US
dc.typeDissertationen_US

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