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—Wireless sensor networks are appealing to researchers due to their wide range of application potential in areas such as target detection and tracking, environmental monitoring, industrial process monitoring, and tactical systems. However, low sensing ranges result in dense networks, which bring the necessity to achieve an efficient medium access protocol(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)
In this paper, a new TDMA based wireless sensor network (WSN) for military monitoring is proposed. The most important design considerations of the newly developed sensor network system are energy consumption, delay, scalability and fault tolerance. There are three main parts of the system: time synchronization based on the sink with high range transmitter,(More)
— Transmission of block-coded images through error-prone 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)
—Multimedia applications are characterized as delay-sensitive 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)