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Unformatted text preview: Opportunistic scheduling in cellular systems in the presence of noncooperative mobiles Veeraruna Kavitha, Eitan Altman, Rachid El-Azouzi and Rajesh Sundaresan Kavitha.Voleti [email protected], [email protected], [email protected], [email protected] Abstract A central scheduling problem in wireless communications is that of allocating resources to one of many mobile stations that have a common radio channel. Much attention has been given to the design of efficient and fair scheduling schemes that are centrally controlled by a base station (BS) whose decisions depend on the channel conditions of each mobile. The BS is the only entity taking decisions in this framework based on truthful information from the mobiles on their radio channel. In this paper, we study the scheduling problem from a game-theoretic perspective in which some of the mobiles may be noncooperative. We model this as a signaling game and study its equilibria. We then propose various approaches to enforce truthful signaling of the radio channel conditions: a pricing approach, an approach based on some knowledge of the mobiles’ policies, and an approach that replaces this knowledge by a stochastic approximations approach that combines estimation and control. We further identify other equilibria that involve nontruthful signaling. I. INTRODUCTION Short-term fading arises in a mobile wireless radio communication system in the presence of scatterers, resulting in time-varying channel gains. Various cellular networks have downlink shared data channels that use scheduling mechanisms to exploit fluctuations in radio conditions (e.g. 3GPP HSDPA  and CDMA/HDR  or 1xEV-DO ). The scheduler design and the obtained gain are predicated on the mobiles sending information concerning the downlink channel 2 gains in a truthful fashion. In a frequency-division duplex system, the base station (BS) has no direct information on the channel gains, but transmits downlink pilots, and relies on the mobiles’ reported values of gains on these pilots for scheduling. A cooperative mobile will truthfully report this information to the BS. A noncooperative mobile will however send a signal that is likely to induce the scheduler to behave in a manner beneficial to the mobile. This paper deals with game-theoretic analysis of downlink scheduling in the presence of noncooperative mobiles. We assume that the identity of players that do not cooperate is common knowledge. We model this initially as a signaling game . Mobiles send signals that correspond to reported channel states and play the role of leaders in the signaling game. The BS allocates the channel resource and plays the role of a follower that reacts to the signals. Mobile utilities (throughputs) are determined by BS’s allocation. BS utility is assumed to be the sum of mobile utilities. We initially focus on the study of equilibria of this game and later on concentrate on robustification of the policies of the BS against noncooperation.robustification of the policies of the BS against noncooperation....
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This note was uploaded on 09/27/2010 for the course EE 229 taught by Professor R.srikant during the Spring '09 term at University of Illinois, Urbana Champaign.
- Spring '09