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Ad Hoc Networks 9 (2011) 142–151

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Ad Hoc Networks
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Joint random access and power control game in ad hoc networks with noncooperative users q
Chengnian Long a,*, Qun Chi a, Xinping Guan a, Tongwen Chen b
a b

Department of Automation, School of Electronic, Information and Electrical Engineering,Shanghai Jiao Tong University, Shanghai, China Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada

a r t i c l e

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a b s t r a c t
We consider a distributed joint random access and power control scheme for interference management in wireless ad hoc networks. To derive decentralized solutions that do not require any cooperation among the users,we formulate this problem as noncooperative joint random access and power control game, in which each user minimizes its average transmission cost with a given rate constraint. Using supermodular game theory, the existence and uniqueness of Nash equilibrium are established. Furthermore, we present an asynchronous distributed algorithm to compute the solution of the game based on myopic bestresponse updates, which converges to Nash equilibrium globally. Finally, a link admission algorithm is carried out to guarantee the reliability of the active users. Performance evaluations via simulations show that the game-theoretical based cross-layer design achieves high performance in terms of energy consumption and network stability. Ó 2010 Elsevier B.V. All rights reserved.

Article history:Available online 19 June 2010 Keywords: Wireless ad hoc networks Random access Power control Supermodular game Nash equilibrium

1. Introduction Since wireless ad hoc networks use a common transmission medium, collision may occur in the presence of simultaneous transmissions by two or more wireless links lying in the interference range of each other. Thus, mitigating interference is a fundamentalproblem for increasing spectral efficiency in wireless ad hoc networks. Important mechanisms for interference management in wireless networks are medium access control (MAC) and power control. This is a complex and intriguing problem since the selection of active link and its power level fundamentally affects many aspects of the operation of the network and its resulting performance; for instancethe quality of the signal received at the receiver, the interference it creates for the other receivers and energy consumption at each node.

q A preliminary version of this work is published in the International Conference on Ad Hoc Networks (ADHOCNETS 2009). * Corresponding author. Tel./fax: +86 21 34204279. E-mail addresses: (C. Long), (Q. Chi), (X. Guan), (T. Chen).

Traditionally, interference management for ad hoc networks is primarily implemented at the lower layers independently. In scheduling-based MAC protocols, e.g. time division multiple access (TDMA)[1,2], the interference management is implemented by a distributed power control for simultaneous active links in a slot. The scheduling problem is todecide in each time slot which source-destination pairs communicate according to some performance index, e.g., maximizing the number of simultaneous transmissions. The power control and scheduling design is separated. In the contention-based MAC protocols, to avoid collision a node accesses the wireless channel with a persistence probability a or waits for a random amount of time bounded by thecontention window CW before a transmission, after it has sensed an idle channel. IEEE 802.11 Distributed Coordination Function (DCF) is a standard contention-based MAC designed for wireless local area networks (WLANs). It should be pointed out that a simple interference/collision model is used where a receiving nodes sees interference from another transmitter if and only if it is within some...
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