195,149 research outputs found
Compensation-based Game for Spectrum Sharing in the Gaussian Interference Channel
This paper considers an optimization problem of sum-rate in the Gaussian frequency-selective channel. We construct a competitive game with an asymptotically optimal compensation to approximate the optimization problem of sum-rate. Once the game achieves the Nash equilibrium, all users in the game will operate at the optimal sum-rate boundary. The contributions of this paper are twofold. On the one hand, a distributed power allocation algorithm called iterative multiple waterlevels water-filling algorithm is proposed to efficiently achieve the Nash equilibrium of the game. On the other hand, we derive some sufficient conditions on the convergence of iterative multiple waterlevels water-filling algorithm in this paper. Through simulation, the proposed algorithm has a significant improvement of the performance over iterative water filling algorithm and achieves the close-to-optimal performance
Closed form solutions for symmetric water filling games
We study power control in optimization and game frameworks. In the
optimization framework there is a single decision maker who assigns network
resources and in the game framework users share the network resources according
to Nash equilibrium. The solution of these problems is based on so-called
water-filling technique, which in turn uses bisection method for solution of
non-linear equations for Lagrange multiplies. Here we provide a closed form
solution to the water-filling problem, which allows us to solve it in a finite
number of operations. Also, we produce a closed form solution for the Nash
equilibrium in symmetric Gaussian interference game with an arbitrary number of
users. Even though the game is symmetric, there is an intrinsic hierarchical
structure induced by the quantity of the resources available to the users. We
use this hierarchical structure to perform a successive reduction of the game.
In addition, to its mathematical beauty, the explicit solution allows one to
study limiting cases when the crosstalk coefficient is either small or large.
We provide an alternative simple proof of the convergence of the Iterative
Water Filling Algorithm. Furthermore, it turns out that the convergence of
Iterative Water Filling Algorithm slows down when the crosstalk coefficient is
large. Using the closed form solution, we can avoid this problem. Finally, we
compare the non-cooperative approach with the cooperative approach and show
that the non-cooperative approach results in a more fair resource distribution
Game theoretic aspects of distributed spectral coordination with application to DSL networks
In this paper we use game theoretic techniques to study the value of
cooperation in distributed spectrum management problems. We show that the
celebrated iterative water-filling algorithm is subject to the prisoner's
dilemma and therefore can lead to severe degradation of the achievable rate
region in an interference channel environment. We also provide thorough
analysis of a simple two bands near-far situation where we are able to provide
closed form tight bounds on the rate region of both fixed margin iterative
water filling (FM-IWF) and dynamic frequency division multiplexing (DFDM)
methods. This is the only case where such analytic expressions are known and
all previous studies included only simulated results of the rate region. We
then propose an alternative algorithm that alleviates some of the drawbacks of
the IWF algorithm in near-far scenarios relevant to DSL access networks. We
also provide experimental analysis based on measured DSL channels of both
algorithms as well as the centralized optimum spectrum management
The Variable-Processor Cup Game
The problem of scheduling tasks on processors so that no task ever gets
too far behind is often described as a game with cups and water. In the
-processor cup game on cups, there are two players, a filler and an
emptier, that take turns adding and removing water from a set of cups. In
each turn, the filler adds units of water to the cups, placing at most
unit of water in each cup, and then the emptier selects cups to remove up
to unit of water from. The emptier's goal is to minimize the backlog, which
is the height of the fullest cup.
The -processor cup game has been studied in many different settings,
dating back to the late 1960's. All of the past work shares one common
assumption: that is fixed. This paper initiates the study of what happens
when the number of available processors varies over time, resulting in what
we call the \emph{variable-processor cup game}.
Remarkably, the optimal bounds for the variable-processor cup game differ
dramatically from its classical counterpart. Whereas the -processor cup has
optimal backlog , the variable-processor game has optimal
backlog . Moreover, there is an efficient filling strategy that
yields backlog in quasi-polynomial time against any
deterministic emptying strategy.
We additionally show that straightforward uses of randomization cannot be
used to help the emptier. In particular, for any positive constant ,
and any -greedy-like randomized emptying algorithm , there
is a filling strategy that achieves backlog against
in quasi-polynomial time
Closed form solutions for symmetric water filling games
We study power control in optimization and game frameworks. In the optimization framework there is a single decision maker who assigns network resources and in the game framework users share the network resources according to Nash equilibrium. The solution of these problems is based on so-called water-filling technique, which in turn uses bisection method for solution of non-linear equations for Lagrange multiplies. Here we provide a closed form solution to the water-filling problem, which allows us to solve it in a finite number of operations. Also, we produce a closed form solution for the Nash equilibrium in symmetric Gaussian interference game with an arbitrary number of users. Even though the game is symmetric, there is an intrinsic hierarchical structure induced by the quantity of the resources available to the users. We use this hierarchical structure to perform a successive reduction of the game. In addition, to its mathematical beauty, the explicit solution allows one to study limiting cases when the crosstalk coefficient is either small or large. We provide an alternative simple proof of the convergence of the Iterative Water Filling Algorithm. Furthermore, it turns out that the convergence of Iterative Water Filling Algorithm slows down when the crosstalk coefficient is large. Using the closed form solution, we can avoid this problem. Finally, we compare the non-cooperative approach with the cooperative approach and show that the non-cooperative approach results in a more fair resource distribution
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