NeXt generation/dynamic spectrum access/cognitive radio wireless networks: a survey
Computer Networks: The International Journal of Computer and Telecommunications Networking
Cognitive Radio Technology (Communications Engineering)
Cognitive Radio Technology (Communications Engineering)
Comparison of Multichannel MAC Protocols
IEEE Transactions on Mobile Computing
CRAHNs: Cognitive radio ad hoc networks
Ad Hoc Networks
Cognitive MANET design for mission-critical networks
IEEE Communications Magazine
Cognitive radio: brain-empowered wireless communications
IEEE Journal on Selected Areas in Communications
Decentralized cognitive MAC for opportunistic spectrum access in ad hoc networks: A POMDP framework
IEEE Journal on Selected Areas in Communications
HC-MAC: A Hardware-Constrained Cognitive MAC for Efficient Spectrum Management
IEEE Journal on Selected Areas in Communications
IEEE Journal on Selected Areas in Communications
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In this paper, we analyze the promising yet mostly unexplored ability of opportunistic spectrum access (OSA) based on cognitive radios (CR) to provide a robust infrastructure for wireless networks operating in challenging environments with frequent transmission link disruptions. We consider a general network model where the CR users can utilize spectrum sensing and channel switching to determine the status of a channel and use a restoration process when a link failure occurs. We first classify the reliability metrics in CR networks based on the perspective and severity of the failures. We then derive analytical relations for the mean time to failure (MTTF) and mean time to repair (MTTR) of the CR users. With the proposed OSA channel restoration scheme, we show that the MTTF between hard failures, where a user cannot communicate for a long interval, increases exponentially with the number of channels available to the CR users. When a failure occurs, the MTTR also decreases exponentially with the number of channels, thereby providing a highly robust communication environment. Finally, we provide design guidelines that can be used to evaluate the tradeoffs between the number of users and channels versus the required reliability.