Transmit Beamforming For Open Spectrum Systems
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Transmit Beamforming for Open Spectrum Systems
[ANGLÈS] This thesis deals with the problem of finding optimal precoding techniques that, considering multiple antennas at the transmitter side, will be able to increase the data rate of future interference networks. First, we present a transmit beamformer that obtains higher sum-rates of the current decentralized designs in asymmetric channel link gains yet preserving a good performance in the general case. From a more theoretical perspective, we derive the achiveable rates of the multiple-input-single-output interference channel via the mathematical framework of multicriteria optimization. Although few results have appeared for solving this problem, we show that all of them can be reformulated as a multicriteria optimization problem and we show their equivalence. Finally, we consider the problem of confidential communication in interference networks that might be required by several wireless communication applications. Relaying on physical layer formulation of the security, we obtain the weighted region when the nonintended receivers do not collude. This is, once each eavesdropper has a weighting factor, we derive the maximum rates that the transmitter can securely communicate with the intended receiver.
Space-Time Coding for Broadband Wireless Communications
Author: Georgios B. Giannakis
language: en
Publisher: John Wiley & Sons
Release Date: 2007-02-26
Eine vielversprechende Technologie zur Maximierung der Bandbreiteneffizienz in der breitbandigen drahtlosen Kommunikation ist die Raum-Zeit-Kodierung. Theorie und Praxis verbindend, ist dieses Buch die erste umfassende Diskussion von Grundlagen und designorientierten Aspekten von Raum-Zeit-Codes. Single-Carrier und Multi-Carrier-Übertragungen für Einzel- und Mehrnutzerkommunikation werden behandelt.
Spectrum Sharing in Wireless Networks
Spectrum Sharing in Wireless Networks: Fairness, Efficiency, and Security provides a broad overview of wireless network spectrum sharing in seven distinct sections: The first section examines the big picture and basic principles, explaining the concepts of spectrum sharing, hardware/software function requirements for efficient sharing, and future trends of sharing strategies. The second section contains more than 10 chapters that discuss differing approaches to efficient spectrum sharing. The authors introduce a new coexistence and sharing scheme for multi-hop networks, describe the space-time sharing concept, introduce LTE-U, and examine sharing in broadcast and unicast environments. They then talk about different cooperation strategies to achieve mutual benefits for primary users (PU) and secondary users (SU), discuss protocols in a spectrum sharing context, and provide different game theory models between PUs and SUs. The third section explains how to model the interactions of PUs and SUs, using an efficient calculation method to determine spectrum availability. Additionally, this section explains how to use scheduling models to achieve efficient SU traffic delivery. The subject of the fourth section is MIMO-oriented design. It focuses on how directional antennas and MIMO antennas greatly enhance wireless network performance. The authors include a few chapters on capacity/rate calculations as well as beamforming issues under MIMO antennas. Power control is covered in the fifth section which also describes the interference-aware power allocation schemes among cognitive radio users and the power control schemes in cognitive radios. The sixth section provides a comprehensive look at security issues, including different types of spectrum sharing attacks and threats as well as corresponding countermeasure schemes. The seventh and final section covers issues pertaining to military applications and examines how the military task protects its data flows when sharing the spectrum with civilian applications.