Fatih Alagöz

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With growing concern on environmental issues and emerging green communications paradigm, cognitive radio (CR) networks have to be considered from energy efficiency perspective. In this work, we focus on scheduling in CR networks (CRNs) in which cognitive base station (CBS) makes frequency allocations to the CRs at the beginning of each frame. A cognitive(More)
Multimedia applications are characterized as delaysensitive and high-bandwidth stipulating traffic sources. Supporting such demanding applications on cognitive radio sensor networks (CRSNs) with energy and spectrum constraints is a highly daunting task. In this paper, we propose a spectrum-aware cluster-based energy-efficient multimedia (SCEEM) routing(More)
We formulate a scheduling problem that takes into account different hardware delays experienced by the secondary users (SUs) in a centralized cognitive radio network (CRN) while switching to different frequency bands. We propose a polynomial-time suboptimal algorithm to address our formulated scheduling problem. We evaluate the impact of varying switching(More)
The fixed spectrum assignment policy in today's wireless networks leads to inefficient spectrum usage. Cognitive radio network is a new communication paradigm that enables the unlicensed users to opportunistically use the spatio-temporally unoccupied portions of the spectrum, and hence realizing a dynamic spectrum access (DSA) methodology. Interference(More)
Transmission of block-coded images through errorprone wireless channels often results in lost blocks. In this study, we investigate a novel error concealment method for covering up these high packet losses and reconstructing a close approximation. Our scheme is a modified discrete wavelet transform (DWT) technique (namely, subbands based image error(More)