We address the problem of joint downlink beamforming and power control in a wireless cellular system, where several users share the same time slot and the same frequency band. In order to enable a fair sharing of reso...
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ISBN:
(纸本)0780374029
We address the problem of joint downlink beamforming and power control in a wireless cellular system, where several users share the same time slot and the same frequency band. In order to enable a fair sharing of resources among all users, the SIR levels should be balanced by minimizing the infinity-norm of a certain vector. To this end, Gerlach and Paulraj [1] proposed an iterative algorithm, which is based on a 1-norm cost function. It has been observed that this algorithm approximates the optimum infinity-norm solution. In this paper we characterize the case where this algorithm is optimal. The analytical results are used to develop a new algorithm, which always converges to the optimum infinity-norm solution, regardless of the chosen initialization. A proof of convergence is given.
In this paper, we introduce the traffic load indicator in a cellular radio system that can be used to characterize the power control problem. The dimension of QoS (Quality of service) constraint equations can be reduc...
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In this paper, we introduce the traffic load indicator in a cellular radio system that can be used to characterize the power control problem. The dimension of QoS (Quality of service) constraint equations can be reduced from the number of MSs (Mobile stations) to the number of base stations (BSs) in the system, and the intercell interference and total received power can be related by traffic load indicator we defined. Theoretical and simulation results show that power control by observing intercell interference can converge faster due to the smaller spectral radius than by measuring total received power.
In this paper, we propose a kind of reconstruction method of discrete-time random signal by utilizing fixed-point principle. Our method is founded by first turning the reconstruction question into a matrix equation, t...
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In this paper, we propose a kind of reconstruction method of discrete-time random signal by utilizing fixed-point principle. Our method is founded by first turning the reconstruction question into a matrix equation, then making use of the relation of circulant matrix and convolution product. We describe the principle of the proposed reconstruction method and its performance.
The investigation of input-output systems often requires a sophisticated choice of test inputs to make the best use of limited experimental time. Here we present an iterative algorithm that continuously adjusts an ens...
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The investigation of input-output systems often requires a sophisticated choice of test inputs to make the best use of limited experimental time. Here we present an iterative algorithm that continuously adjusts an ensemble of test inputs on-line, subject to the data already acquired about the system under study. The algorithm focuses the input ensemble by maximizing the mutual information between input and output. We apply the algorithm to simulated neurophysiological experiments and show that it serves to extract the ensemble of stimuli that a given neural system “expects” as a result of its natural history.
algorithms are sought for attitude determination using global positioning system (GPS) differential phase measurements, assuming that the cycle integer ambiguities are known. The problem of attitude determination is p...
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algorithms are sought for attitude determination using global positioning system (GPS) differential phase measurements, assuming that the cycle integer ambiguities are known. The problem of attitude determination is posed as a constrained parameter optimization problem, where a quaternion-based quartic cost function is used. A new general minimization scheme is developed. The new scheme is a continuous version of the well-known Newton-Raphson algorithm and is based on the solution of an ordinary differential equation. The new continuous algorithm converges exponentially from any initial condition to the closest local minimum located on the gradient direction in regions where the associated Hessian matrix is positive definite. Three new algorithms are developed for solving the attitude estimation problem, a discrete Newton-Raphson-based algorithm, a continuous Newton-Raphson algorithm, and an algorithm that is based on the eigenproblem structure of the nonlinear equations, which are related to the minimization of the quartic cost function. The performance of the new algorithms is evaluated via numerical examples and compared with each other and against the well-known QUEST algorithm. The continuous Newton-Raphson algorithm and the eigenproblem algorithm have similar accuracy. The discrete Newton-Raphson algorithm is less efficient than the continuous Newton-Raphson algorithm in the examined minimization because its search may wander and may even reach a nonrelevant extreme. When the GPS satellites are at low elevation, the accuracy of the new algorithms is better than that of QUEST, when the latter is applied to vectorized phase measurements.
It is known that the measured equation of invariance (MEI) is generally valid for outgoing waves just as other absorbing boundary conditions (ABC's), However, for the scattering problem of multicylinders, the scat...
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It is known that the measured equation of invariance (MEI) is generally valid for outgoing waves just as other absorbing boundary conditions (ABC's), However, for the scattering problem of multicylinders, the scattered field from one cylinder is just the in-going incident wave to other cylinders. So the MEI cannot be directly applied to the scattering problem of multicylinders. In this paper, an iterative algorithm based on the MEI is first proposed for the scattering problems of multicylinders with arbitrary geometry and physical parameters, Each cylinder is coated with several layers of meshes and the MEI's are applied to the truncated mesh boundaries. It has been demonstrated that the MEI can truncate the meshes very close to the surfaces of the cylinders and then results in dramatically savings in memory requirements and computational time. The MEI coefficients of each cylinder can be stored and reused to form the sparse matrices during each iteration procedure as they are independent of excitations. So more central processing unit (CPU) time is saved as the MEI coefficients are calculated only once in the algorithm. The method can be applied to problems of various kinds of multiple cylinders with arbitrary configurations and cross sections. Numerical results for the scattered fields are in good agreement with the data available. Finally, examples are given to show the iterative algorithm applicable to electrically large multicylinders coated with lossy media.
Focuses on a study which presented monotonic iterative algorithms for solving quasicomplementarity problem (QCP). Details on the sequential complementarity problem (CP) algorithm; Information on the supersolution and ...
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Focuses on a study which presented monotonic iterative algorithms for solving quasicomplementarity problem (QCP). Details on the sequential complementarity problem (CP) algorithm; Information on the supersolution and subsolution of CP to QCP; Equation of Schwarz algorithm.
Domain decomposition method (DDM) based on the Schwarz alternating method is divergent when it is used to analyze waveguide problems. In the paper, an absorbing fictitious boundary condition (FBC) is presented to gene...
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Domain decomposition method (DDM) based on the Schwarz alternating method is divergent when it is used to analyze waveguide problems. In the paper, an absorbing fictitious boundary condition (FBC) is presented to generate an iterative DDM for waveguide problems. The FBC which connects the subdomains on fictitious boundaries is developed according to the actual field distribution in the waveguide to ensure the propagation of waves between adjacent subdomains. And the relaxation algorithm is introduced to improve the speed of iterative convergence. Finally, a number of numerical examples are given to demonstrate its efficiency.
In this paper, we extend the auxiliary principle technique to study a class of generalized set-valued strongly nonlinear mixed variational-like inequalities. We prove the existence of a solution of the auxiliary probl...
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In this paper, we extend the auxiliary principle technique to study a class of generalized set-valued strongly nonlinear mixed variational-like inequalities. We prove the existence of a solution of the auxiliary problem for the generalized set-valued strongly nonlinear mixed variational-like inequalities, construct the iterative algorithm for the generalized set-valued strongly nonlinear mixed variational-like inequalities, and show the existence of a solution of the generalized set-valued strongly nonlinear mixed variational-like inequality by using the auxiliary principle technique. We also prove the convergence of iterative sequences generated by the algorithm. (C) 2001 Academic Press.
Based on a new iterative algorithm, the solvability of a class of nonlinear variational inequalities involving a combination of relaxed monotone operators in a Hilbert space setting is presented. (C) 1999 Elsevier Sci...
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Based on a new iterative algorithm, the solvability of a class of nonlinear variational inequalities involving a combination of relaxed monotone operators in a Hilbert space setting is presented. (C) 1999 Elsevier Science Ltd. All rights reserved.
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