Fundamentals of wireless communication
Fundamentals of wireless communication
Spectrum Challenges and Solutions by Cognitive Radio: An Overview
Wireless Personal Communications: An International Journal
In-band spectrum sensing in cognitive radio networks: energy detection or feature detection?
Proceedings of the 14th ACM international conference on Mobile computing and networking
Spectrum sensing for cognitive radio
RWS'09 Proceedings of the 4th international conference on Radio and wireless symposium
Multi-antenna interference cancellation techniques for cognitive radio applications
WCNC'09 Proceedings of the 2009 IEEE conference on Wireless Communications & Networking Conference
Upper bound on the capacity of cognitive radio without cooperation
IEEE Transactions on Wireless Communications
Spectrum sensing in cognitive radio using goodness of fit testing
IEEE Transactions on Wireless Communications
Restless watchdog: selective quickest spectrum sensing in multichannel cognitive radio systems
EURASIP Journal on Advances in Signal Processing - Special issue on dynamic spectrum access for wireless networking
Emerging cognitive radio technology: Principles, challenges and opportunities
Computers and Electrical Engineering
Restless watchdog: monitoring multiple bands with blind period in cognitive radio systems
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Bayesian potential games to model cooperation for cognitive radios with incomplete information
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Cognitive radios with multiple antennas exploiting spatial opportunities
IEEE Transactions on Signal Processing
Is oversensitive spectrum sensing the door opener for initial cognitive radio deployments?
Proceedings of the 2010 ACM workshop on Wireless of the students, by the students, for the students
Cognitive engine design for link adaptation: an application to multi-antenna systems
IEEE Transactions on Wireless Communications
Efficient QoS support for secondary users in cognitive radio systems
IEEE Wireless Communications
The problem of sensing unused cellular spectrum
NETWORKING'11 Proceedings of the 10th international IFIP TC 6 conference on Networking - Volume Part II
Spectrum Sensing Framework for Cognitive Radio Networks
Wireless Personal Communications: An International Journal
Spectrum sensing and power/rate control in CDMA cognitive radio networks
International Journal of Communication Systems
Wireless Personal Communications: An International Journal
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Under the current system of spectrum allocation, rigid partitioning has resulted in vastly underutilized spectrum bands, even in urban locales. Cognitive radios have been proposed as a way to reuse this underutilized spectrum in an opportunistic manner. To achieve this reuse while guaranteeing non-interference with the primary user, cognitive radios must detect very weak primary signals. However, uncertainties in the noise+interference impose a limit on how low of a primary signal can be robustly detected. In this paper, we show that the presence/absence of possible interference from other opportunistic spectrum users represents a major component of the uncertainty limiting the ability of a cognitive radio network to reclaim a band for its use. Coordination among nearby cognitive radios is required to control this uncertainty. While this coordination can take a form similar to a traditional MAC protocol for data communication, its role is different in that it aims to reduce the uncertainty about interference rather than just reducing the interference itself. We show how the degree of coordination required can vary based on the coherence times and bandwidths involved, as well as the complexity of the detectors themselves. The simplest sensing strategies end up needing the most coordination, while more complex strategies involving adaptive coherent processing and interference prediction can be individually more robust and thereby reduce the need for coordination across different networks. We also show the existence of a coordination radius wall which limits secondary user densities that can be supported irrespective of coordination involved. Furthermore, local cooperation among cognitive radios for collective decision making can reduce the fading margins we need to budget for. This cooperation benefits from increased secondary user densities and hence induces a minima in the power-coordination tradeoff.