1,006 research outputs found
Self-optimizing load balancing with backhaul-constrained radio access networks
Self-Organizing Network (SON) technology aims at autonomously deploying,
optimizing and repairing the Radio Access Networks (RAN). SON algorithms
typically use Key Performance Indicators (KPIs) from the RAN. It is shown that
in certain cases, it is essential to take into account the impact of the
backhaul state in the design of the SON algorithm. We revisit the Base Station
(BS) load definition taking into account the backhaul state. We provide an
analytical formula for the load along with a simple estimator for both elastic
and guaranteed bit-rate (GBR) traffic. We incorporate the proposed load
estimator in a self-optimized load balancing algorithm. Simulation results for
a backhaul constrained heterogeneous network illustrate how the correct load
definition can guarantee a proper operation of the SON algorithm.Comment: Wireless Communications Letters, IEEE, 201
Self Organizing strategies for enhanced ICIC (eICIC)
Small cells have been identified as an effective solution for coping with the
important traffic increase that is expected in the coming years. But this
solution is accompanied by additional interference that needs to be mitigated.
The enhanced Inter Cell Interference Coordination (eICIC) feature has been
introduced to address the interference problem. eICIC involves two parameters
which need to be optimized, namely the Cell Range Extension (CRE) of the small
cells and the ABS ratio (ABSr) which defines a mute ratio for the macro cell to
reduce the interference it produces. In this paper we propose self-optimizing
algorithms for the eICIC. The CRE is adjusted by means of load balancing
algorithm. The ABSr parameter is optimized by maximizing a proportional fair
utility of user throughputs. The convergence of the algorithms is proven using
stochastic approximation theorems. Numerical simulations illustrate the
important performance gain brought about by the different algorithms.Comment: Submitted to WiOpt 201
Load Balancing Congestion Games and their Asymptotic Behavior
A central question in routing games has been to establish conditions for the
uniqueness of the equilibrium, either in terms of network topology or in terms
of costs. This question is well understood in two classes of routing games. The
first is the non-atomic routing introduced by Wardrop on 1952 in the context of
road traffic in which each player (car) is infinitesimally small; a single car
has a negligible impact on the congestion. Each car wishes to minimize its
expected delay. Under arbitrary topology, such games are known to have a convex
potential and thus a unique equilibrium. The second framework is splitable
atomic games: there are finitely many players, each controlling the route of a
population of individuals (let them be cars in road traffic or packets in the
communication networks). In this paper, we study two other frameworks of
routing games in which each of several players has an integer number of
connections (which are population of packets) to route and where there is a
constraint that a connection cannot be split. Through a particular game with a
simple three link topology, we identify various novel and surprising properties
of games within these frameworks. We show in particular that equilibria are non
unique even in the potential game setting of Rosenthal with strictly convex
link costs. We further show that non-symmetric equilibria arise in symmetric
networks. I. INTRODUCTION A central question in routing games has been to
establish conditions for the uniqueness of the equilibria, either in terms of
the network topology or in terms of the costs. A survey on these issues is
given in [1]. The question of uniqueness of equilibria has been studied in two
different frameworks. The first, which we call F1, is the non-atomic routing
introduced by Wardrop on 1952 in the context of road traffic in which each
player (car) is infinitesimally small; a single car has a negligible impact on
the congestion. Each car wishes to minimize its expected delay. Under arbitrary
topology, such games are known to have a convex potential and thus have a
unique equilibrium [2]. The second framework, denoted by F2, is splitable
atomic games. There are finitely many players, each controlling the route of a
population of individuals. This type of games have already been studied in the
context of road traffic by Haurie and Marcotte [3] but have become central in
the telecom community to model routing decisions of Internet Service Providers
that can decide how to split the traffic of their subscribers among various
routes so as to minimize network congestion [4]. In this paper we study
properties of equilibria in two other frameworks of routing games which exhibit
surprisin
Applying branching processes to delay-tolerant networks
Mobility models that have been used in the past to study delay tolerant networks (DTNs) have been either too complex to allow for deriving analytical expressions for performance measures, or have been too simplistic. In this paper we identify several classes of DTNs where the dynamics of the number of nodes that have a copy of some packet can be modeled as branching process with migration. Using recent results on such processes in a random environment, we obtain explicit formulae for the first two moments of the number of copies of a file that is propagated in the DTN, for quite general mobility models. Numerical examples illustrate our approach
Distributed coordination of self-organizing mechanisms in communication networks
The fast development of the Self-Organizing Network (SON) technology in
mobile networks renders the problem of coordinating SON functionalities
operating simultaneously critical. SON functionalities can be viewed as control
loops that may need to be coordinated to guarantee conflict free operation, to
enforce stability of the network and to achieve performance gain. This paper
proposes a distributed solution for coordinating SON functionalities. It uses
Rosen's concave games framework in conjunction with convex optimization. The
SON functionalities are modeled as linear Ordinary Differential Equation
(ODE)s. The stability of the system is first evaluated using a basic control
theory approach. The coordination solution consists in finding a linear map
(called coordination matrix) that stabilizes the system of SON functionalities.
It is proven that the solution remains valid in a noisy environment using
Stochastic Approximation. A practical example involving three different SON
functionalities deployed in Base Stations (BSs) of a Long Term Evolution (LTE)
network demonstrates the usefulness of the proposed method.Comment: submitted to IEEE TCNS. arXiv admin note: substantial text overlap
with arXiv:1209.123
A hybrid decision approach for the association problem in heterogeneous networks
The area of networking games has had a growing impact on wireless networks.
This reflects the recognition in the important scaling advantages that the
service providers can benefit from by increasing the autonomy of mobiles in
decision making. This may however result in inefficiencies that are inherent to
equilibria in non-cooperative games. Due to the concern for efficiency,
centralized protocols keep being considered and compared to decentralized ones.
From the point of view of the network architecture, this implies the
co-existence of network-centric and terminal centric radio resource management
schemes. Instead of taking part within the debate among the supporters of each
solution, we propose in this paper hybrid schemes where the wireless users are
assisted in their decisions by the network that broadcasts aggregated load
information. We derive the utilities related to the Quality of Service (QoS)
perceived by the users and develop a Bayesian framework to obtain the
equilibria. Numerical results illustrate the advantages of using our hybrid
game framework in an association problem in a network composed of HSDPA and 3G
LTE systems.Comment: 5 pages, 4 figures, IEEE Infocom, San Diego, USA, March 2010
Multilevel Pricing Schemes in a Deregulated Wireless Network Market
Typically the cost of a product, a good or a service has many components.
Those components come from different complex steps in the supply chain of the
product from sourcing to distribution. This economic point of view also takes
place in the determination of goods and services in wireless networks. Indeed,
before transmitting customer data, a network operator has to lease some
frequency range from a spectrum owner and also has to establish agreements with
electricity suppliers. The goal of this paper is to compare two pricing
schemes, namely a power-based and a flat rate, and give a possible explanation
why flat rate pricing schemes are more common than power based pricing ones in
a deregulated wireless market. We suggest a hierarchical game-theoretical model
of a three level supply chain: the end users, the service provider and the
spectrum owner. The end users intend to transmit data on a wireless network.
The amount of traffic sent by the end users depends on the available frequency
bandwidth as well as the price they have to pay for their transmission. A
natural question arises for the service provider: how to design an efficient
pricing scheme in order to maximize his profit. Moreover he has to take into
account the lease charge he has to pay to the spectrum owner and how many
frequency bandwidth to rent. The spectrum owner itself also looks for
maximizing its profit and has to determine the lease price to the service
provider. The equilibrium at each level of our supply chain model are
established and several properties are investigated. In particular, in the case
of a power-based pricing scheme, the service provider and the spectrum owner
tend to share the gross provider profit. Whereas, considering the flat rate
pricing scheme, if the end users are going to exploit the network intensively,
then the tariffs of the suppliers (spectrum owner and service provider)
explode.Comment: This is the last draft version of the paper. Revised version of the
paper accepted by ValueTools 2013 can be found in Proceedings of the 7th
International Conference on Performance Evaluation Methodologies and Tools
(ValueTools '13), December 10-12, 2013, Turin, Ital
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