Fabio E. Lapiccirella

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We investigate an opportunistic channel access problem over multiple primary frequency bands. We exploit primary ACK/NAK packets overheard by the secondary users to overlay their communications on top of active primary channels. Applying the theory of multiarmed restless bandit (MARB), we determine the conditions that are needed for proving the optimality(More)
Cognitive radio networks enable secondary users to utilize spare bandwidth of primary users by limiting their interference. Moving beyond the traditional listen-before-talk paradigm, we propose a cognitive access methodology that exploits the feedback channel in two-way primary communication links for better spectrum utility and protection of primary users(More)
We explore a flexible and non-intrusive opportunistic spectrum access control mechanism for cognitive radios that goes beyond the standard “Listen-Before-Talk” (LBT) strategy. We exploit the bi-directional nature of many primary communication systems to control cognitive radio access that is based on both spectral sensing and primary receiver(More)
In this paper, we investigate distributed control of multiple secondary users attempting to access the channel of a high priority primary user. Our aim is to maximize the sum cognitive (secondary) user throughput under the constraint of primary user’s queue stability. We consider the effect of primary user link adaptation that allows the primary transmitter(More)
Cognitive radio systems capable of opportunistic spectrum access represent a new paradigm for improving the efficiency of current spectrum utilization. In this work, we present a novel cognitive channel access method based on learning from both primary channel transmissions and the receiver ARQ feedback signals. This new sensing-plus-confirmation scheme(More)
We propose a network access optimization for cognitive radio nodes aimed at throughput maximization under the constraint of primary node queue stability. To maintain primary queue stability, our approach moves beyond the traditional listen-before-talk opportunistic access by allowing cognitive radios to over-hear and utilize ACK/NAK feedback signals on(More)
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