Virtual Cooperation for Throughput Maximization in Distributed Large-Scale Wireless Networks
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Research Article Virtual Cooperation for Throughput Maximization in Distributed Large-Scale Wireless Networks Jamshid Abouei,1 Alireza Bayesteh,2 Masoud Ebrahimi,2 and Amir K. Khandani2 1
Department of Electrical Engineering, Yazd University, P.O. Box 98195-741, Yazd, Iran of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON, Canada N2L 3G1
2 Department
Correspondence should be addressed to Jamshid Abouei, [email protected] Received 28 May 2010; Revised 12 September 2010; Accepted 29 October 2010 Academic Editor: Robert Schober Copyright © 2011 Jamshid Abouei et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A distributed wireless network with K links is considered, where the links are partitioned into M clusters each operating in a subchannel with bandwidth W/M. The subchannels are assumed to be orthogonal to each other. A general shadow-fading model described by the probability of shadowing α and the average cross-link gains ≤ 1 is considered. The main goal is to find the maximum network throughput in the asymptotic regime of K → ∞, which is achieved by: (i) proposing a distributed power allocation strategy, where the objective of each user is to maximize its best estimate (based on its local information) of the average network throughput and (ii) choosing the optimum value for M. In the first part, the network throughput is defined as the average sum-rate of the network, which is shown to scale as Θ(log K). It is proved that the optimum power allocation strategy for each user for large K is a threshold-based on-off scheme. In the second part, the network throughput is defined as the guaranteed sumrate, when the outage probability approaches zero. It is demonstrated that the on-off power scheme maximizes the throughput, which scales as (W/α) log K. Moreover, the optimum spectrum sharing for maximizing the average sum-rate and the guaranteed sum-rate is achieved at M = 1.
1. Introduction A primary challenge in wireless networks is to use available resources efficiently so that the network throughput is maximized. Throughput maximization in multiuser wireless networks has been addressed from different perspectives, resource allocation [1–3], routing by using relay nodes [4], exploiting mobility of the nodes [5], and exploiting channel characteristics (e.g., power decay versus distance law [6–8], geometric path loss and fading [9]). Among different resource allocation strategies, power and spectrum allocation have long been regarded as efficient tools to mitigate the interference and improve the network throughput. In recent years, power and spectrum allocation schemes have been extensively studied in cellular and multihop wireless networks [1, 2, 10–12]. In [11], the authors provide a comprehensive survey in the area of resource allocation, in particular in the context of spectrum assignment. Much of these works rely on
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