Article
Achievable Rates and Scaling Laws of PowerConstrained Wireless Sensory Relay Networks
Dept. of Electr. Eng., Arizona State Univ., Tempe, AZ
IEEE Transactions on Information Theory (Impact Factor: 2.62). 10/2006; DOI: 10.1109/TIT.2006.880029 Source: DBLP

Conference Paper: Capacity analysis and power allocation under imperfect channel estimation for AFbased cooperative relay systems
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ABSTRACT: In this paper, we investigate the effect of channel estimation errors on the capacity of amplifyandforward cooperative relay systems. Since an exact capacity expression in the presence of channel estimation errors is difficult to be found, we turn to derive its lower bound instead. Accordingly, by maximizing the derived lower bound, we propose power allocation schemes for both singlerelay and multirelay systems. For singlerelay systems, an analytical solution for inequality constrained problem is too complicated to be obtained. Thus, we propose a gradient descent algorithm with a logbarrier function to solve the inequality constrained problem. For multirelay systems, in terms of the channel estimates and the corresponding meansquared errors, we provide a waterfilling solution for the optimal power allocation among the relays. Simulation results show that the proposed power allocation schemes yield capacity gain compared with equal power allocation at low to medium signaltonoise ratios.Global Communications Conference (GLOBECOM), 2012 IEEE; 01/2012  [Show abstract] [Hide abstract]
ABSTRACT: A novel representation for a twohop decentralized wireless relay network (DWRN) is proposed, where the relays operate in a completely distributive fashion. The modeling paradigm applies an analogous approach to the description method for doubledirectional multipath propagation channels and takes into account finite system spatial resolution and extended relay listening/transmitting time. Specifically, the double and singledirectional information azimuth spectra (IAS) are formulated to provide a compact representation of information flows in the DWRN. The proposed analytical framework is then studied from a geometrybased statistical modeling perspective. Finally, we look into the problem of relay network tomography (RNT), which solves an inverse problem to infer the internal structure of an unknown relay network by using the doubledirectional IAS recorded at multiple measuring nodes exterior to the relay region. Numerical examples are presented to demonstrate the efficacy of the suggested channel description method and the RNT algorithm.IEEE Transactions on Vehicular Technology 01/2012; 61(2):455465. · 2.06 Impact Factor 
Conference Paper: Bursty wideband relay networks
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ABSTRACT: In wireless networks, the use of cooperation among nodes can significantly improve capacity and robustness to fading. However, many cooperation techniques have been developed for operation in narrowband systems for high signaltonoise ratio (SNR) applications. It is important to study how relay networks perform in a wideband regime, where the available degrees of freedom is large and the resulting SNR per degree of freedom is small. In this paper, taking into account wideband transmissions with fixed power (W → ∞), we investigate the achievable rates and scaling laws of bursty amplifyandforward relay networks in the wideband regime. Specifically, our results allow us to understand the effect of different system parameters on the achievable rates and scaling laws in the wideband regime, and highlight the role of bursty transmissions in this regime. We identify four scaling regimes that depend on the growth of the number of relay nodes and the increase of burstiness relative to the SNR. These results can serve as design guidelines to indicate when bursty transmissions are most useful.Proceedings of the 2009 IEEE conference on Wireless Communications & Networking Conference; 04/2009
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