Decentralized Beamformer Design with Limited Multi-Cell Cooperation for Interference Channel of Cognitive Radio Networks

• Published in: IEEE transactions on wireless communications Vol. 12; no. 8; pp. 4142 - 4152
• Main Authors: KIM, Young-Jin, SONG, Moon-Gun, CHO, Yong-Sang, IM, Gi-Hong
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-08-2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Applied sciences; Array signal processing; Channels; Cognitive radio; Cooperation; Decentralized; Design engineering; Detection, estimation, filtering, equalization, prediction; Exact sciences and technology; Heuristic; Information, signal and communications theory; Interference; limited cooperation; multiple antenna; Operations research; Optimization; Radiocommunication specific techniques; Radiocommunications; Resource management; Robustness; Scattering; Signal and communications theory; Signal, noise; spectrum sharing; Studies; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Transmitters; Transmitters. Receivers; weighted sum-rate maximization; Performance evaluation; Parameter estimation; limited cooperation; Intercarrier interference; Transmitter; Resource sharing; Cognitive radio; Algorithm; Power allocation; Beam forming; Relaxation; Networked system; multiple antenna; Simulation; Decentralized system; Channel estimation; Multiple system; Signal processing; weighted sum-rate maximization; Intercell interference; Antenna array; Radio communication; Software radio; spectrum sharing
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2013.071913.121996

In spectrum-sharing-based cognitive radio networks, multiple secondary systems can access a licensed spectrum to better utilize scarce radio resources. When the multiple secondary transmitters are co-located, the weighted sum-rate of the secondary users (SUs) is mainly limited by the inter-cell interference (ICI). With limited cooperation among co-located secondary transmitters, we propose an algorithm for decentralized beamforming with power allocation via dual decomposition. To maximize the weighted sum-rate of the SUs, the proposed decentralized algorithm efficiently mitigates the ICI by the undesired leakage power limitation at each secondary transmitter. Because the channel information is not perfectly known at the transmitter in practical applications, we also develop a decentralized robust beamformer. To efficiently design the robust beamformer, a convex problem is formulated by semi-definite relaxation. Simulation results show that the proposed algorithm with perfect channel state information (P-CSI) efficiently maximizes the weighted sum-rate performance by the undesired leakage power limitation. For an imperfect CSI with a small error bound, the proposed robust beamformer approaches the performance of a P-CSI case, without causing harmful interference to the primary user.