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Full-Text Articles in Computer Engineering
The Biobjective Multiarmed Bandit: Learning Approximate Lexicographic Optimal Allocations, Cem Teki̇n
The Biobjective Multiarmed Bandit: Learning Approximate Lexicographic Optimal Allocations, Cem Teki̇n
Turkish Journal of Electrical Engineering and Computer Sciences
We consider a biobjective sequential decision-making problem where an allocation (arm) is called $\epsilon$ lexicographic optimal if its expected reward in the first objective is at most $\epsilon$ smaller than the highest expected reward, and its expected reward in the second objective is at least the expected reward of a lexicographic optimal arm. The goal of the learner is to select arms that are $\epsilon$ lexicographic optimal as much as possible without knowing the arm reward distributions beforehand. For this problem, we first show that the learner's goal is equivalent to minimizing the $\epsilon$ lexicographic regret, and then, propose a …
Transparent Spectrum Co-Access In Cognitive Radio Networks, Jonathan Daniel Backens
Transparent Spectrum Co-Access In Cognitive Radio Networks, Jonathan Daniel Backens
Electrical & Computer Engineering Theses & Dissertations
The licensed wireless spectrum is currently under-utilized by as much as 85%. Cognitive radio networks have been proposed to employ dynamic spectrum access to share this under-utilized spectrum between licensed primary user transmissions and unlicensed secondary user transmissions. Current secondary user opportunistic spectrum access methods, however, remain limited in their ability to provide enough incentive to convince primary users to share the licensed spectrum, and they rely on primary user absence to guarantee secondary user performance. These challenges are addressed by developing a Dynamic Spectrum Co-Access Architecture (DSCA) that allows secondary user transmissions to co-access transparently and concurrently with primary …
Distributed Beamforming With Imperfect Phase Synchronization For Cognitive Radio Networks, Andrew Minturn, Deepraj Vernekar, Yaoqing Lamar Yang, Hamid Sharif
Distributed Beamforming With Imperfect Phase Synchronization For Cognitive Radio Networks, Andrew Minturn, Deepraj Vernekar, Yaoqing Lamar Yang, Hamid Sharif
Department of Electrical and Computer Engineering: Faculty Publications
In this paper, we present the analysis and simulation evaluation of a cognitive radio network employing a distributed beamforming technique with imperfect phase synchronization in the presence of a primary receiver. Our system model consists of a group of cognitive transmitters, each with an ideal isotropic antenna and equal transmit power, communicating with a secondary receiver in the farfield. The objective of the network of cognitive transmitters is to optimize its beampattern in the direction of the secondary receiver while minimizing the beampattern in the direction of the primary receiver to a certain threshold. The phases of the transmitted signals …
Smart Sensing And Performance Analysis For Cognitive Radio Networks, Yanxiao Zhao
Smart Sensing And Performance Analysis For Cognitive Radio Networks, Yanxiao Zhao
Electrical & Computer Engineering Theses & Dissertations
Static spectrum access policy has resulted in spectrum scarcity as well as low spectrum utility in today's wireless communications. To utilize the limited spectrum more efficiently, cognitive radio networks have been considered a promising paradigm for future network. Due to the unique features of cognitive radio technology, cognitive radio networks not only raise new challenges, but also bring several fundamental problems back to the focus of researchers. So far, a number of problems in cognitive radio networks have remained unsolved over the past decade. The work presented in this dissertation attempts to fill some of the gaps in the research …