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160
Distributed interference compensation for wireless networks
 IEEE Journal on Selected Areas in Communications
, 2006
"... Abstract—We consider a distributed power control scheme for wireless ad hoc networks, in which each user announces a price that reflects compensation paid by other users for their interference. We present an asynchronous distributed algorithm for updating power levels and prices. By relating this al ..."
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Cited by 90 (22 self)
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Abstract—We consider a distributed power control scheme for wireless ad hoc networks, in which each user announces a price that reflects compensation paid by other users for their interference. We present an asynchronous distributed algorithm for updating power levels and prices. By relating this algorithm to myopic best response updates in a fictitious game, we are able to characterize convergence using supermodular game theory. Extensions of this algorithm to a multichannel network are also presented, in which users can allocate their power across multiple frequency bands. Index Terms—Distributed algorithms, game theory, power control, pricing. I.
Demand Responsive Pricing and Competitive Spectrum Allocation via a Spectrum Server
 In Proc. of IEEE DySPAN
, 2005
"... Abstract — In this paper we develop a framework for competition of future operators likely to operate in a mixed commons/propertyrights regime under the regulation of a spectrum policy server (SPS). The operators dynamically compete for customers as well as portions of available spectrum. The opera ..."
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Cited by 75 (4 self)
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Abstract — In this paper we develop a framework for competition of future operators likely to operate in a mixed commons/propertyrights regime under the regulation of a spectrum policy server (SPS). The operators dynamically compete for customers as well as portions of available spectrum. The operators are charged by the SPS for the amount of bandwidth they use in their services. Through demand responsive pricing, the operators try to come up with convincing service offers for the customers, while trying to maximize their profits. We first consider a singleuser system as an illustrative example. We formulate the competition between the operators as a noncooperative game and propose an SPSbased iterative bidding scheme that results in a Nash equilibrium of the game. Numerical results suggest that, competition increases the user’s (customer’s) acceptance probability of the offered service, while reducing the profits achieved by the operators. It is also observed that as the cost of unit bandwidth increases relative to the cost of unit infrastructure (fixed cost), the operator with superior technology (higher fixed cost) becomes more competitive. We then extend the framework to a multiuser setting where the operators are competing for a number of users at once. We propose an SPSbased bandwidth allocation scheme in which the SPS optimally allocates bandwidth portions for each useroperator session to maximize its overall expected revenue resulting from the operator payments. Comparison of the performance of this scheme to one in which the bandwidth is equally shared between the useroperator pairs reveals that such an SPSbased scheme improves the user acceptance probabilities and the bandwidth utilization in multiuser systems. I.
Optimized Signaling for MIMO Interference Systems with Feedback
"... The system mutual information of a multipleinput multipleoutput (MIMO) system with multiple users which mutually interfere is considered. Perfect channel state information is assumed to be known to both transmitters and receivers. Asymptotic performance analysis shows that the system mutual info ..."
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Cited by 49 (0 self)
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The system mutual information of a multipleinput multipleoutput (MIMO) system with multiple users which mutually interfere is considered. Perfect channel state information is assumed to be known to both transmitters and receivers. Asymptotic performance analysis shows that the system mutual information changes behavior as the interference becomes sufficiently strong. In particular, beamforming is the optimum signaling for all users when the interference is large. We propose several numerical approaches to decide the covariance matrices of the transmitted signals and compare their performance in terms of the system mutual information. We model the system as a noncooperative game, and perform iterative waterfilling to find the Nash equilibrium distributively. A centralized global approach and a distributed iterative approach based on the gradient projection method are also proposed. Numerical results show that all proposed approaches give better performance than the standard signaling which is optimum for the case without interference. Both the global and the iterative gradient projection methods are shown to outperform the Nash equilibrium significantly.
Auctionbased spectrum sharing
 WiOpt '04
, 2004
"... Abstract. We study auctionbased mechanisms for sharing spectrum among a group of users, subject to a constraint on the interference temperature at collocated receivers. The users access the channel using spread spectrum signaling and thus generate interference with each other. Each user receives a ..."
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Cited by 48 (8 self)
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Abstract. We study auctionbased mechanisms for sharing spectrum among a group of users, subject to a constraint on the interference temperature at collocated receivers. The users access the channel using spread spectrum signaling and thus generate interference with each other. Each user receives a utility that is a function of the received signaltointerference plus noise ratio. We propose two auction mechanisms for allocating the received power. The first is an SINRbased auction, which, when combined with logarithmic utilities, leads to a weighted maxmin fair SINR allocation. The second is a powerbased auction that maximizes the total utility when the bandwidth is large enough. Both auction mechanisms achieve social optimality in a large system limit where bandwidth, power and the number of users are increased in a fixed proportion. We also give sufficient conditions for global convergence of a distributed updating algorithm and discuss the convergence speed. 1
An energyefficient approach to power control and receiver design in wireless data networks
 IEEE TRANSACTIONS ON COMMUNICATIONS
, 2005
"... In this work, the crosslayer design problem of joint multiuser detection and power control is studied using a gametheoretic approach that focuses on energy efficiency. The uplink of a directsequence code division multiple access (DSCDMA) data network is considered and a noncooperative game is ..."
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Cited by 45 (14 self)
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In this work, the crosslayer design problem of joint multiuser detection and power control is studied using a gametheoretic approach that focuses on energy efficiency. The uplink of a directsequence code division multiple access (DSCDMA) data network is considered and a noncooperative game is proposed in which users in the network are allowed to choose their uplink receivers as well as their transmit powers to maximize their own utilities. The utility function measures the number of reliable bits transmitted by the user per joule of energy consumed. Focusing on linear receivers, the Nash equilibrium for the proposed game is derived. It is shown that the equilibrium is one where the powers are SIRbalanced with the minimum mean square error (MMSE) detector as the receiver. In addition, this framework is used to study power control games for the matched filter, the decorrelator, and the MMSE detector; and the receivers’ performance is compared in terms of the utilities achieved at equilibrium (in bits/Joule). The optimal cooperative solution is also discussed and compared with the noncooperative approach. Extensions of the results to the case of multiple receive antennas are also presented. In addition, an admission control scheme based on maximizing the total utility in the network is proposed.
A gametheoretic approach to energyefficient power control in multicarrier CDMA systems
 IEEE Journal on Selected Areas in Communications (JSAC
, 2006
"... Abstract—A gametheoretic model for studying power control in multicarrier codedivision multipleaccess systems is proposed. Power control is modeled as a noncooperative game in which each user decides how much power to transmit over each carrier to maximize its own utility. The utility function co ..."
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Cited by 42 (8 self)
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Abstract—A gametheoretic model for studying power control in multicarrier codedivision multipleaccess systems is proposed. Power control is modeled as a noncooperative game in which each user decides how much power to transmit over each carrier to maximize its own utility. The utility function considered here measures the number of reliable bits transmitted over all the carriers per joule of energy consumed and is particularly suitable for networks where energy efficiency is important. The multidimensional nature of users ’ strategies and the nonquasiconcavity of the utility function make the multicarrier problem much more challenging than the singlecarrier or throughputbasedutility case. It is shown that, for all linear receivers including the matched filter, the decorrelator, and the minimummeansquareerror detector, a user’s utility is maximized when the user transmits only on its “best ” carrier. This is the carrier that requires the least amount of power to achieve a particular target signaltointerferenceplusnoise ratio at the output of the receiver. The existence and uniqueness of Nash equilibrium for the proposed power control game are studied. In particular, conditions are given that must be satisfied by the channel gains for a Nash equilibrium to exist, and the distribution of the users among the carriers at equilibrium is characterized. In addition, an iterative and distributed algorithm for reaching the equilibrium (when it exists) is presented. It is shown that the proposed approach results in significant improvements in the total utility achieved at equilibrium compared with a singlecarrier system and also to a multicarrier system in which each user maximizes its utility over each carrier independently. Index Terms—Energy efficiency, game theory, multicarrier codedivision multipleaccess (CDMA), multiuser detection, Nash equilibrium, power control, utility function. I.
On selfish behavior in CSMA/CA networks
 In Proc. of IEEE Infocom
, 2005
"... Abstract — CSMA/CA protocols rely on the random deferment of packet transmissions. Like most other protocols, CSMA/CA was designed with the assumption that the nodes would play by the rules. This can be dangerous, since the nodes themselves control their random deferment. Indeed, with the higher pro ..."
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Cited by 38 (6 self)
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Abstract — CSMA/CA protocols rely on the random deferment of packet transmissions. Like most other protocols, CSMA/CA was designed with the assumption that the nodes would play by the rules. This can be dangerous, since the nodes themselves control their random deferment. Indeed, with the higher programmability of the network adapters, the temptation to tamper with the software or firmware is likely to grow; by doing so, a user could obtain a much larger share of the available bandwidth at the expense of other users. We use a gametheoretic approach to investigate the problem of the selfish behavior of nodes in CSMA/CA networks, specifically geared towards the most widely accepted protocol in this class of protocols, IEEE 802.11. We characterize two families of Nash equilibria in a single stage game, one of which always results in a network collapse. We argue that this result provides an incentive for cheaters to cooperate with each other. Explicit cooperation among nodes is clearly impractical. By applying the model of dynamic games borrowed from game theory, we derive the conditions for the stable and optimal functioning of a population of cheaters. We use this insight to develop a simple, localized and distributed protocol that successfully guides multiple selfish nodes to a Paretooptimal Nash equilibrium. I.
A CrossLayer Optimization Framework for Multihop Multicast in Wireless Mesh Networks
 JOURNAL ON SELECTED AREAS IN COMMUNICATIONS (JSAC
, 2006
"... The optimal and distributed provisioning of high throughput in mesh networks is known as a fundamental but hard problem. The situation is exacerbated in a wireless setting due to the interference among local wireless transmissions. In this paper, we propose a crosslayer optimization framework for ..."
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Cited by 37 (8 self)
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The optimal and distributed provisioning of high throughput in mesh networks is known as a fundamental but hard problem. The situation is exacerbated in a wireless setting due to the interference among local wireless transmissions. In this paper, we propose a crosslayer optimization framework for throughput maximization in wireless mesh networks, in which the data routing problem and the wireless medium contention problem are jointly optimized for multihop multicast. We show that the throughput maximization problem can be decomposed into two subproblems: a data routing subproblem at the network layer, and a power control subproblem at the physical layer with a set of Lagrangian dual variables coordinating interlayer coupling. Various effective solutions are discussed for each subproblem. We emphasize the network coding technique for multicast routing and a game theoretic method for interference management, for which efficient and distributed solutions are derived and illustrated. Finally, we show that the proposed framework can be extended to take into account physicallayer wireless multicast in mesh networks.
SModular Games and Power Control in Wireless Networks
 IEEE Transactions on Automatic Control
, 2003
"... This note shows how centralized or distributed power control algorithms in wireless communications can be viewed as Smodular games coupled policy sets (coupling is due to the fact that the set of powers of a mobile that satisfy the signaltointerference ratio constraints depends on powers used by ..."
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Cited by 31 (4 self)
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This note shows how centralized or distributed power control algorithms in wireless communications can be viewed as Smodular games coupled policy sets (coupling is due to the fact that the set of powers of a mobile that satisfy the signaltointerference ratio constraints depends on powers used by other mobiles). This sheds a new light on convergence properties of existing synchronous and asynchronous algorithms, and allows us to establish new convergence results of power control algorithms. Furthermore, known properties of power control algorithms allow us to extend the theory of Smodular games and obtain conditions for the uniqueness of the equilibrium and convergence of best response algorithms independently of the initial state.