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IEEE Trans. Mob. Comput. 01/2010; 9:1242-1254.
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ABSTRACT: Dynamic spectrum access has become a promising approach to fully utilize the scarce spectrum resources. In a dynamically changing spectrum environment, it is very important to consider the statistics of different users' spectrum access so as to achieve more efficient spectrum allocation. In this paper, we propose a primary-prioritized Markov approach for dynamic spectrum access through modeling the interactions between the primary and the secondary users as continuous-time Markov chains (CTMC). Based on the CTMC models, to compensate the throughput degradation due to the interference among secondary users, we derive the optimal access probabilities for the secondary users, by which the spectrum access of the secondary users is optimally coordinated, and the spectrum dynamics are clearly captured. Therefore, a good tradeoff can be achieved between the spectrum efficiency and fairness. The simulation results show that the proposed primary-prioritized dynamic spectrum access approach under proportional fairness criterion achieves much higher throughput than the CSMA-based random access approaches and the approach achieving max-min fairness. Moreover, it provides fair spectrum sharing among secondary users with only small performance degradation compared to the approach maximizing the overall average throughput.
IEEE Transactions on Wireless Communications 05/2009; · 2.59 Impact Factor
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IEEE Transactions on Wireless Communications. 01/2009; 8:1854-1865.
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ABSTRACT: Dynamic spectrum access with cognitive radios has become a promising approach to improve spectrum efficiency by adaptively coordinating different users' access according to spectrum dynamics. However, selfish users competing with each other for spectrum may exchange false private information or collude with others to get more access to the spectrum and achieve higher profits. In this article, we investigate two game-theoretical mechanism design methods to suppress cheating and collusion behavior of selfish users: a self-enforcing truth-telling mechanism for unlicensed spectrum sharing and a collusion-resistant multistage dynamic spectrum pricing game for licensed spectrum sharing.
IEEE Signal Processing Magazine 12/2008; · 4.07 Impact Factor
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ABSTRACT: In self-organized mobile ad hoc networks (MANETs) where each user is its own authority, fully cooperative behaviors, such as unconditionally forwarding packets for each other or honestly revealing its private information, cannot be directly assumed. The pricing mechanism is one way to provide incentives for the users to act cooperatively by awarding some payment for cooperative behaviors. In this paper, we consider efficient routing in self-organized MANETs and model it as multi-stage dynamic pricing games. A game theoretical framework for dynamic pricing-based routing in MANETs is proposed to maximize the sender/receiveriquests payoff by considering the dynamic nature of MANETs. Meanwhile, the forwarding incentives of the relay nodes can also be maintained by optimally pricing their packet-forwarding services based on the auction rules and introducing the cartel maintenance enforcing mechanism. The simulation results illustrate that the proposed dynamic pricing-based routing approach has significant performance gains over the existing static pricing approaches.
IEEE Journal on Selected Areas in Communications 10/2008; · 3.41 Impact Factor
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ABSTRACT: In distributed wireless networks without centralized control, each user is its own authority to maximize its own performance. This distributed characteristic provides the users with the incentives of greedy competitions for the network resources such as bandwidth and transmission time. Such competitions deteriorate the system performance dramatically and result in low non-cooperative performances. Ensuring cooperation among selfish users can improve the performances and thus becomes an important issue for such wireless networks. In this paper, a Cartel Maintenance repeated game framework is proposed to enforce the cooperation among selfish users. The soul of Cartel Maintenance is to construct contracts among independent individuals for cooperative benefits and non-cooperative punishment, so as to limit inefficient competitions. In the proposed framework, a trigger-punishment game rule is designed to encourage the users to follow the cooperative strategy. First, all users agree to cooperate. Then in the following time slot, if users observe the others play cooperatively, cooperation will be played. If some users detect that others may defect based on the observed information, these users will play punishment phases for a certain period of time. This punishment is optimized so that the gain obtained by the deviation users is outweighed by the future punishments. Therefore, no user has the incentives to deviate, and the cooperation among selfish users is enforced. Then, the framework is employed to the multiple random access scenarios in wireless networks with selfish users, where the closed-form optimal solutions of cooperation enforcement are derived. The simulation results show that the proposed scheme can achieve significant performance gains over the non-cooperation scheme by having enough punishment threat to keep the cooperation among users.
IEEE Transactions on Wireless Communications 06/2008; · 2.59 Impact Factor
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ABSTRACT: In order to fully utilize scarce spectrum resources, dynamic spectrum allocation becomes a promising approach to increase the spectrum efficiency for wireless networks. However, the collusion among selfish network users may seriously deteriorate the efficiency of dynamic spectrum sharing. The network users' behaviors and dynamics need to be taken into consideration for efficient and robust spectrum allocation. In this paper, we model the spectrum allocation in wireless networks with multiple selfish legacy spectrum holders and unlicensed users as multi-stage dynamic games. In order to combat user collusion, we propose a pricing-based collusion-resistant dynamic spectrum allocation approach to optimize overall spectrum efficiency, while not only keeping the participating incentives of the selfish users but also combating possible user collusion. The simulation results show that the proposed scheme achieves high efficiency of spectrum usage even with the presence of severe user collusion.
IEEE Journal on Selected Areas in Communications 02/2008; · 3.41 Impact Factor
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IEEE Journal on Selected Areas in Communications. 01/2008; 26:182-191.
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IEEE Journal on Selected Areas in Communications. 01/2008; 26:1204-1217.
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IEEE Transactions on Wireless Communications. 01/2008; 7:1889-1899.
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ABSTRACT: In this paper, a distributive non-cooperative game is proposed to perform sub-channel assignment, adaptive modulation, and power control for multi-cell multi-user orthogonal frequency division multiplexing access (OFDMA) networks. Each individual user's goal is to minimize his/her own transmitted power in a distributed manner under the constraints that the desirable rate is achieved and the transmitted power is bounded. The pure non-cooperative game may result in non-convergence or some undesirable Nash Equilibriums with low system and individual performances. To enhance the performances, a virtual referee is introduced to the networks and is in charge of monitoring and improving the outcome of non-cooperative competition for resources among the distributed users. If the game outcome is not desirable, either the required transmission rates should be reduced or some users should be prevented from using some radio resources such as sub-channels, so that the rest of users can share the limited resources more efficiently. Moreover, it can be shown that the introduction of the virtual referee does not increase the complexity of the networks. From the simulation results in a two-cell case, the proposed scheme reduces the transmitted power by 80% and 25% compared with the fixed channel assignment algorithm and the iterative water-filling algorithm in the literature, respectively. The achievable rate can be improved by 10%. In a multi-cell case, the proposed scheme can have up to 40% power reduction compared with the iterative water-filling algorithm when the co-channel interferences are severe.
IEEE Journal on Selected Areas in Communications 09/2007; · 3.41 Impact Factor
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ABSTRACT: Dynamic spectrum access has become a promising approach to fully utilize the scarce spectrum resources. In a dynamically changing spectrum environment, it is very important to design a distributed access scheme that can coordinate different users' access adapt to spectrum dynamics with only local information. In this paper, we propose a self-learning repeated game framework for distributed primary-prioritized dynamic spectrum access through modeling the interactions between secondary users as a noncooperative game. With the proposed framework, the inefficiency due to users' selfish behavior can be highly improved, and the secondary users can distributively obtain their optimal access probabilities with only local observations. The simulation results show that the proposed framework can achieve comparable performances with those of the centralized primary-prioritized dynamic spectrum aess sheme.
Networking Technologies for Software Define Radio Networks, 2007 2nd IEEE Workshop on; 07/2007
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ABSTRACT: Dynamic spectrum access has become a promising approach to fully utilize the scarce spectrum resources. In a dynamically changing spectrum environment, it is very important to design a distributed access scheme that can coordinate different users' access adapt to spectrum dynamics with only local information. In this paper, we propose a self-learning repeated game framework for distributed primary-prioritized dynamic spectrum access through modeling the interactions between secondary users as a noncooperative game. With the proposed framework, the inefficiency due to users' selfish behavior can be highly improved, and the secondary users can distributively obtain their optimal access probabilities with only local observations. The simulation results show that the proposed framework can achieve comparable performances with those of the centralized primary-prioritized dynamic spectrum access scheme.
Sensor, Mesh and Ad Hoc Communications and Networks, 2007. SECON '07. 4th Annual IEEE Communications Society Conference on; 07/2007
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ABSTRACT: In order to fully utilize the scarce spectrum resources, with the development of cognitive radio technologies, dynamic spectrum sharing becomes a promising approach to increase the efficiency of spectrum usage. Game theoretical dynamic spectrum sharing has been extensively studied for more flexible, efficient, and fair spectrum usage through analyzing the intelligent behaviors of network users equipped with cognitive radio devices. This article provides a game theoretical overview of dynamic spectrum sharing from several aspects: analysis of network users' behaviors, efficient dynamic distributed design, and optimality analysis
IEEE Communications Magazine 06/2007; · 3.79 Impact Factor
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ABSTRACT: Dynamic spectrum allocation becomes a promising approach to increase the spectrum efficiency for wireless networks. However, the collusion among selfish network users may seriously deteriorate the efficiency of dynamic spectrum sharing. In this paper, we propose a collusion-resistant dynamic pricing approach to optimize overall spectrum efficiency in the scenarios of user collusion. The simulation results show that our proposed scheme achieves high efficiency of spectrum usage even with the presence of severe user collusion.
New Frontiers in Dynamic Spectrum Access Networks, 2007. DySPAN 2007. 2nd IEEE International Symposium on; 05/2007
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ABSTRACT: In order to fully utilize the scarce spectrum resources, with the development of cognitive radio technologies, dynamic spectrum access becomes a promising approach to increase the efficiency of spectrum usage. The spectrum access can be designed in an opportunistic way to efficiently and fairly share the spectrum resources among multiple unlicensed users, while not disturbing primary users' spectrum usage. In this paper, we propose a primary-prioritized Markov approach for dynamic spectrum access through modeling the interactions between the primary users and the unlicensed users as continuous- time Markov chains (CTMC). By designing appropriate access probabilities for the unlicensed users, the spectrum dynamics can be captured using CTMC models to optimally coordinate the spectrum access of the unlicensed users so that a good tradeoff can be achieved between the spectrum efficiency and fairness. The simulation results show that the proposed primary-prioritized dynamic spectrum access approach under proportional fairness criterion not only provides fair spectrum sharing among unlicensed users with only small performance degradation compared to the approach maximizing the overall average throughput, but also achieves much higher throughput than CSMA-based random access approaches and the approach achieving max-min fairness.
New Frontiers in Dynamic Spectrum Access Networks, 2007. DySPAN 2007. 2nd IEEE International Symposium on; 05/2007
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IEEE Journal on Selected Areas in Communications. 01/2007; 25:1079-1090.
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IEEE Transactions on Information Forensics and Security. 01/2007; 2:240-253.
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ABSTRACT: Dynamic spectrum allocation becomes a promising approach to increase the spectrum efficiency for wireless networks. In this paper, we consider the spectrum allocation in wireless networks with multiple selfish legacy spectrum holders and unlicensed users as multi-stage dynamic games. A dynamic pricing approach is proposed to optimize overall spectrum efficiency while keeping the participating incentives of the users based on double-auction rules. Moreover, a belief system is developed to assist selfish users to dynamically update their strategies adaptive to the network dynamics and substantially decrease the pricing overhead. The simulation results show that our proposed scheme not only approaches optimal outcomes but also has low overhead.
Global Telecommunications Conference, 2006. GLOBECOM '06. IEEE; 01/2007
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ABSTRACT: In order to fully utilize the scarce spectrum resources, with the development of cognitive radio technologies, dynamic spectrum allocation becomes a promising approach to increase the efficiency of spectrum usage. In this paper, we consider the spectrum allocation in wireless networks with multiple selfish legacy spectrum holders and unlicensed users as multi-stage dynamic games. A belief-assisted dynamic pricing approach is proposed to optimize overall spectrum efficiency while keeping the participating incentives of the users based on double auction rules. Moreover, considering the budget constraints of the unlicensed users, a dynamic programming approach is further developed to optimize the spectrum allocation over time. The simulation results show that our proposed scheme not only approaches optimal outcomes with low overhead compared to general continuous double auction mechanisms, but also fully exploits the time diversity of spectrum resources when budget constraints exist
Sensor and Ad Hoc Communications and Networks, 2006. SECON '06. 2006 3rd Annual IEEE Communications Society on; 10/2006
