Journal ArticleDOI
Cooperative diversity in wireless networks: Efficient protocols and outage behavior
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Using distributed antennas, this work develops and analyzes low-complexity cooperative diversity protocols that combat fading induced by multipath propagation in wireless networks and develops performance characterizations in terms of outage events and associated outage probabilities, which measure robustness of the transmissions to fading.Abstract:
We develop and analyze low-complexity cooperative diversity protocols that combat fading induced by multipath propagation in wireless networks. The underlying techniques exploit space diversity available through cooperating terminals' relaying signals for one another. We outline several strategies employed by the cooperating radios, including fixed relaying schemes such as amplify-and-forward and decode-and-forward, selection relaying schemes that adapt based upon channel measurements between the cooperating terminals, and incremental relaying schemes that adapt based upon limited feedback from the destination terminal. We develop performance characterizations in terms of outage events and associated outage probabilities, which measure robustness of the transmissions to fading, focusing on the high signal-to-noise ratio (SNR) regime. Except for fixed decode-and-forward, all of our cooperative diversity protocols are efficient in the sense that they achieve full diversity (i.e., second-order diversity in the case of two terminals), and, moreover, are close to optimum (within 1.5 dB) in certain regimes. Thus, using distributed antennas, we can provide the powerful benefits of space diversity without need for physical arrays, though at a loss of spectral efficiency due to half-duplex operation and possibly at the cost of additional receive hardware. Applicable to any wireless setting, including cellular or ad hoc networks-wherever space constraints preclude the use of physical arrays-the performance characterizations reveal that large power or energy savings result from the use of these protocols.read more
Citations
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Journal ArticleDOI
Performance Study of Two-Hop Amplify-and-Forward Systems With Untrustworthy Relay Nodes
TL;DR: This work reveals an interesting result that, when the relay nodes are untrustworthy, the system performance worsens as the number of relays increases, and proposes a secure relay selection scheme that can maximize the achievable secrecy rate.
Journal ArticleDOI
Adaptive two-way relaying and outage analysis
TL;DR: A simple adaptive protocol is considered in the two-way relaying scenario, which switches between AF and DF depending on the decodability of the two bi-directional data streams at the relay, and it always outperforms the non-adaptive schemes.
Journal ArticleDOI
Multiuser Relaying over Mixed RF/FSO Links
TL;DR: Investigation of a multiuser dual-hop relaying system over mixed radio frequency/free-space optical links finds engineering insights are manifested, such as the coding and diversity gain of each user, the impact of the pointing error displacement on the FSO link and the V-BLAST ordering effectiveness at the relay.
Journal ArticleDOI
Statistical channel knowledge-based optimum power allocation for relaying protocols in the high SNR regime
TL;DR: The results show that optimal power allocation brings impressive coding gains over equal power allocation, and the analysis reveals that the coding gain gap between the AF and DF protocols can also be reduced by the optimalPower allocation.
Journal ArticleDOI
Channel Capacity Over Generalized Fading Channels: A Novel MGF-Based Approach for Performance Analysis and Design of Wireless Communication Systems
TL;DR: A novel and unified communication-theoretic framework for the analysis of channel capacity over fading channels is proposed and it is shown that the framework can handle various fading channel models, communication types, and adaptation transmission policies.
References
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TL;DR: WireWireless Communications: Principles and Practice, Second Edition is the definitive modern text for wireless communications technology and system design as discussed by the authors, which covers the fundamental issues impacting all wireless networks and reviews virtually every important new wireless standard and technological development, offering especially comprehensive coverage of the 3G systems and wireless local area networks (WLANs).
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Digital communications
TL;DR: This month's guest columnist, Steve Bible, N7HPR, is completing a master’s degree in computer science at the Naval Postgraduate School in Monterey, California, and his research area closely follows his interest in amateur radio.
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