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Cognitive radio (CR) has been emerging as a new technology enabling unlicensed secondary users (SUs) to dynamically access licensed spectrum bands underutilized by primary users (PUs). Spectrum sensing plays an important role in CR systems to detect PU inactivity and the resulting spectrum holes that allow dynamic spectrum access by SUs. In most existing spectrum sensing schemes, dynamics of the channel...
Cognitive Radio has become an effective theory to solve inefficient spectrum usage. The traffic of Wi-Fi data increases rapidly because of smart phones and netbooks. IEEE 802.22 standard supposes a cognitive radio system which consists of one licensed primary user (PU) and multiple unlicensed secondary user(SU)s. The SUs utilize the licensed spectrum while the PU is absence. In this paper, we consider...
Frequency agility is considered as an indispensable feature of next-generation wireless sensor networks (WSNs), which will have to cope with highly interfered environments due to the increasing diffusion of wireless devices operating in unlicensed bands. In this paper we investigate some design aspects related to spectrum sensing in “cognitive” WSNs, relating the duration of sensing time to the probability...
We consider a scenario in which the secondary users opportunistic access the spectrum allocated to the primary user if the spectrum is sensed idle. In cognitive radio network, no matter what methods the secondary users use to sense, there are always missing detection and false alarm. Missing detection and false alarm probabilities characterize the protection to the primary user and the channel utilization...
This paper looks into the modeling of information transmission over cognitive interrogator-sensor networks (CISNs), which represent an import class of sensor networks deployed for surveillance, tracking, and imaging applications. The crux of the problem is to develop a channel model that allows for evaluation of the sensing channel capacity and error rate performance, where the sensing link is overlaid...
Spectrum sensing is a critical issue in cognitive radio networks. Cooperation among the secondary users is utilized to improve the performance of spectrum sensing. In this paper, we quantify the gain of cooperation in spectrum sensing by introducing the concept of diversity order. With different system performance metrics, we introduce different diversity quantities. We analyze the single-user sensing...
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