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TitleInterference management in cognitive radio systems with feasibility detection
Publication TypeJournal Article
Year of Publication2013
AuthorsSingh, S., Teal P.D., Dmochowski P.A., and Coulson A.J.
JournalIEEE Transactions on Vehicular Technology
Pagination3711 - 3720
Date Published2013
ISSN00189545 (ISSN)
KeywordsCognitive radio, Communication systems, Convex optimization, Convex optimization techniques, Cumulative distribution function, Geometric programming, Interference management, Optimization problems, Outage probability, Peak-power constraints, Power control, Quality of service, Radio systems, Signal interference, Spurious signal noise, Wireless communication system
AbstractIn this paper, we consider a cognitive radio system with N secondary user (SU) pairs sharing a spectrum with a pair of primary users (PUs). The SU power allocation problem is formulated as a capacity maximization problem under PU and SU quality of service (QoS) and SU peak power constraints. We show that our problem formulation is a geometric program and can be solved with convex optimization techniques. We examine the effect of PU transmissions in our formulations. Solutions for both low- and high-signal-to-interference-and-noise ratio (SINR) scenarios are provided. We show that including PU capacity in the optimization problem in some circumstances leads to increased PU performance while not significantly degrading SU capacity. In a practical wireless communication system, accurate channel state information (CSI) is not often available; hence, we formulate power allocation problems with both perfect and imperfect CSI and analyze the performance loss incurred due to imperfect CSI. Furthermore, we present a novel method of detecting and removing infeasible SU QoS constraints from the SU power allocation problem that results in considerably improved SU performance. Cumulative distribution functions of capacity for various Rayleigh fading channels are presented. © 1967-2012 IEEE.

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