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Stochastic power control for cellular radio systems
 IEEE Transactions on Communications
, 1998
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Adaptive power control and MMSE interference suppression
 Wireless Networks
, 1998
"... Power control algorithms assume that the receiver structure is fixed and iteratively update the transmit powers of the users to provide acceptable quality of service while minimizing the total transmitter power. Multiuser detection, on the other hand, optimizes the receiver structure with the assump ..."
Abstract

Cited by 45 (4 self)
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Power control algorithms assume that the receiver structure is fixed and iteratively update the transmit powers of the users to provide acceptable quality of service while minimizing the total transmitter power. Multiuser detection, on the other hand, optimizes the receiver structure with the assumption that the users have fixed transmitter powers. In this study, we combine the two approaches and propose an iterative and distributed power control algorithm which iteratively updates the transmitter powers and receiver filter coefficients of the users. We show that the algorithm converges to a minimum power solution for the powers, and an MMSE multiuser detector for the filter coefficients. 1.
Stochastic learning solution for distributed discrete power control game in wireless data networks
, 2008
"... Distributed power control is an important issue in wireless networks. Recently, noncooperative game theory has been applied to investigate interesting solutions to this problem. The majority of these studies assumes that the transmitter power level can take values in a continuous domain. However, r ..."
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Cited by 25 (0 self)
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Distributed power control is an important issue in wireless networks. Recently, noncooperative game theory has been applied to investigate interesting solutions to this problem. The majority of these studies assumes that the transmitter power level can take values in a continuous domain. However, recent trends such as the GSM standard and Qualcomm’s proposal to the IS95 standard use a finite number of discretized power levels. This motivates the need to investigate solutions for distributed discrete power control which is the primary objective of this paper. We first note that, by simply discretizing, the previously proposed continuous power adaptation techniques will not suffice. This is because a simple discretization does not guarantee convergence and uniqueness. We propose two probabilistic power adaptation algorithms and analyze their theoretical properties along with the numerical behavior. The distributed discrete power control problem is formulated as anperson, nonzero sum game. In this game, each user evaluates a power strategy by computing a utility value. This evaluation is performed using a stochastic iterative procedures. We approximate the discrete power control iterations by an equivalent ordinary differential equation to prove that the proposed stochastic learning power control algorithm converges to a stable Nash equilibrium. Conditions when more than one stable Nash equilibrium or even only mixed equilibrium may exist are also studied. Experimental results are presented for several cases and compared with the continuous power level adaptation solutions.
Optimal Power Control in CDMA Networks with Constraints on Outage Probability
 in Proc. WiOpt’03, INRIA Sophia Antipolis
, 2003
"... This paper proposes a new scheme that couples power control with a minimum outage probability multiuser detector. The resultant iterative algorithm is conceptually simple and finds the minimum sum power of all users with a set of outage probability constraints. Bounds on the outage probability expre ..."
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Cited by 3 (1 self)
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This paper proposes a new scheme that couples power control with a minimum outage probability multiuser detector. The resultant iterative algorithm is conceptually simple and finds the minimum sum power of all users with a set of outage probability constraints. Bounds on the outage probability expression are found that extend a previous result that did not include receiver noise. These bounds are used to create a suboptimal scheme coupling power control and a MMSE multiuser detector. This new problem becomes a variant of an existing problem where outage probability constraints are first mapped to average SIR threshold constraints. Using a recent result that transforms complex SIR expressions into a compact and decoupled form, a noniterative and computationally inexpensive power control algorithm is developed for large systems of users. Simulation results are presented showing the closeness of the optimal and mapped schemes, speed of convergence and performance comparisons with other standard receivers.
Optimal power control in CDMA networks with constraints on outage probability”, WiOpt 2003  Modeling and optimization in mobile, ad hoc and wireless networks
, 2003
"... Abstract — This paper proposes a new scheme that couples power control with a minimum outage probability multiuser detector. The resultant iterative algorithm is conceptually simple and finds the minimum sum power of all users with a set of outage probability constraints. Bounds on the outage probab ..."
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Cited by 1 (0 self)
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Abstract — This paper proposes a new scheme that couples power control with a minimum outage probability multiuser detector. The resultant iterative algorithm is conceptually simple and finds the minimum sum power of all users with a set of outage probability constraints. Bounds on the outage probability expression are found that extend a previous result that did not include receiver noise. These bounds are used to create a suboptimal scheme coupling power control and a MMSE multiuser detector. This new problem becomes a variant of an existing problem where outage probability constraints are first mapped to average SIR threshold constraints. Using a recent result that transforms complex SIR expressions into a compact and decoupled form, a noniterative and computationally inexpensive power control algorithm is developed for large systems of users. Simulation results are presented showing the closeness of the optimal and mapped schemes, speed of convergence and performance comparisons with other standard receivers. Index Terms — CDMA, Decorrelator, large system analysis, MMSE receiver, multiuser detection, outage probability, power control. I.
OutageBased Optimal Power Control for Generalized Multiuser Fading Channels
"... Abstract—We address the problem of achieving outage probability constraints on the uplink of a codedivision multipleaccess (CDMA) system employing power control and linear multiuser detection, where we aim to minimize the total expended power. We propose a generalized framework for solving such p ..."
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Abstract—We address the problem of achieving outage probability constraints on the uplink of a codedivision multipleaccess (CDMA) system employing power control and linear multiuser detection, where we aim to minimize the total expended power. We propose a generalized framework for solving such problems under modest assumptions on the underlying channel fading distribution. Unlike previous work, which dealt with a Rayleigh fastfading model, we allow each user to have a different fading distribution. We show how this problem can be formed as an optimization over user transmit powers and linear receivers, and, where the problem is feasible, we provide conceptually simple iterative algorithms that find the minimum power solution while achieving outage specifications with equality. We further generalize a mapping from outage probability specifications to average signaltointerferenceratio constraints that was previously applicable only to Rayleighfaded channels. This mapping allows us to develop suboptimal, computationally efficient algorithms to solve the original problem. Numerical results are provided that validate the iterative schemes, showing the closeness of the optimal and mapped solutions, even under circumstances where the map does not guarantee that constraints will be achieved. Index Terms—Code division multiple access (CDMA), multiuser detection, Nakagami fading, outage probability, power control. I.
Optimal Power Control for RayleighFaded Multiuser Systems With Outage Constraints
"... Abstract—How can we achieve the conflicting goals of reduced transmission power and increased capacity in a wireless network, without attempting to follow the instantaneous state of a fading channel? In this paper, we address this problem by jointly considering power control and multiuser detection ..."
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Abstract—How can we achieve the conflicting goals of reduced transmission power and increased capacity in a wireless network, without attempting to follow the instantaneous state of a fading channel? In this paper, we address this problem by jointly considering power control and multiuser detection (MUD) with outageprobability constraints in a Rayleigh fastfading environment. The resulting powercontrol algorithms (PCAs) utilize the statistics of the channel and operate on a much slower timescale than traditional schemes. We propose an optimal iterative solution that is conceptually simple and finds the minimum sum power of all users while meeting their outage targets. Using a derived bound on outage probability, we introduce a mapping from outage to average signaltointerference ratio (SIR) constraints. This allows us to propose a suboptimal iterative scheme that is a variation of an existing solution to a joint power control and MUD problem involving SIR constraints. We further use a recent result that transforms complex SIR expressions into a compact and decoupled form, to develop a noniterative and computationally inexpensive PCA for large systems of users. Simulation results are presented showing the closeness of the optimal and mapped schemes, speed of convergence, and performance comparisons. Index Terms—Code division multiple access (CDMA), large