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Optimal received SINR balancing based on cooperative beamforming in cognitive radio networks
Author(s) -
Moghaddam Javad Zeraatkar,
Farrokhi Hamid,
Granelli Fabrizio
Publication year - 2016
Publication title -
international journal of communication systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.344
H-Index - 49
eISSN - 1099-1131
pISSN - 1074-5351
DOI - 10.1002/dac.3173
Subject(s) - computer science , beamforming , cognitive radio , robustness (evolution) , relay , signal to interference plus noise ratio , interference (communication) , mathematical optimization , computer network , telecommunications , power (physics) , wireless , mathematics , channel (broadcasting) , biochemistry , chemistry , physics , quantum mechanics , gene
Summary In this paper, we investigate a two‐step cooperative cognitive radio network, which consists of two secondary links, a number of relays, and one primary link. During the first step, the primary link is assumed to be idle; both secondary sources simultaneously broadcast their data to the relay network. During the second step, the relay network employs a proposed cooperative beamforming (CBF) scheme and transmits the received data toward both of the secondary destinations (no matter whether the primary link is idle or not). The proposed CBF scheme enables the investigated network to simultaneously maximize received signal to interference plus noise ratio at both of the secondary destinations while keeping interference plus noise power at the primary destination under a predefined threshold. Indeed, the proposed scheme represents an optimal received signal to interference plus noise ratio balancing approach based on CBF, which guarantees the required quality of service for the primary link and also both secondary links. We optimize the CBF vector by relaxing the optimization problem to a convex semidefinite programming and solving with the bisection search algorithm. Numerical results show the efficiency and robustness of our approach. A comparison of our approach with the zero‐forcing beamforming method is also presented. Copyright © 2016 John Wiley & Sons, Ltd.