In this talk, we present a hybrid resource allocation model for OFDMATDMA wireless networks and a... more In this talk, we present a hybrid resource allocation model for OFDMATDMA wireless networks and an algorithmic framework using a Variable Neighborhood Search metaheuristic approach for solving the problem. The model is aimed at maximizing the total bandwidth channel capacity of an uplink OFDMA-TDMA network subject to user power and subcarrier assignment constraints while simultaneously scheduling users in time. As such, the model is best suited for non-real time applications where subchannel multiuser diversity can be further exploited simultaneously in frequency and in time domains. The VNS approach is constructed upon a key aspect of the proposed model, namely its decomposition structure. Our numerical results show tight bounds for the proposed algorithm, e.g. less than 2% in most of the instances. Finally, the bounds are obtained at a very low computational cost.
... Backbone network design in communications network (Bogdanowicz, 1993); Routing in packet-swit... more ... Backbone network design in communications network (Bogdanowicz, 1993); Routing in packet-switched networks (Ribeiro and Elbaz, 1992); Virtual ... and to other packing and covering problems (see Garg and Konemann (1998); Grigoriadis and Khachiyan (1994); Leighton et al ...
In this paper, we discuss the optimal design of telecommunications networks prone to failure. The... more In this paper, we discuss the optimal design of telecommunications networks prone to failure. The problem concerns mid-range planning objectives. The purpose of the model is to give insight on the cost of protecting the network against failures by balancing the choice of a base routing of the demands and the investment in spare to protect the routing against elementary breakdowns. The problem in formulated as a large linear programming model. To exploit the structure we resort to a decomposition scheme with two nested levels. At the higher level, we propose two different schemes: a Lagrangian relaxation and a decomposition "a la Benders". The transformed problem is solved by a cutting plane method. We compare two such methods, the Cheney-Goldstein-Kelly method and the analytic center cutting plane method. The methods are tested on a set of realistic problems
A telecommunication network is survivable if, following an arc failure, the interrupted traffic c... more A telecommunication network is survivable if, following an arc failure, the interrupted traffic can be redirected through the network via existing excess capacity. The standard survivability problem consists in finding the least cost investment in spare capacity to allow rerouting of a given base traffic. In this paper we consider the more involved problem of simultaneously designing the base traffic and the spare capacity investment. If the investment costs are linear, the problem can be formulated as a large scale structured linear program that we solve using different decomposition techniques, including the analytic center cutting plane method. The global analysis is performed under the assumption of local rerouting of the traffic, i.e., the interrupted traffic creates a local demand between the end points of the broken edge. More sophisticated telecommunication network management allows to break down the interrupted traffic into its individual demand components. We do not treat ...
Recent advances in optical fiber systems and transmission equipments play a primary role in today... more Recent advances in optical fiber systems and transmission equipments play a primary role in today's telecommunications networks. The standardized SDH (Synchronous Digital Hierarchy) technology made the rings the most survivable architecture for designing high speed networks. Designing such networks involves not only the configuration of rings at the logical level but also the mapping of such configurations on the physical level, i.e. fiber paths. This paper deals with the problem of finding optimal clusters of nodes to be used as the basis for designing logical rings. In the simplest form, this problem is equivalent to k-equipartition, and can be modeled as a quadratic pseudo-boolean problem. We consider both linear and semidefinite relaxations and present numerical results on real data from France Telecom networks with up 900 nodes, and also on randomly generated problems.
Experimentation de quelques variantes de l'algorithme de Karmarkar qui ont permis d'elabo... more Experimentation de quelques variantes de l'algorithme de Karmarkar qui ont permis d'elaborer un logiciel plus performant que la version originelle. Plusieurs methodes ont ete testees; il s'agit en particulier: de la forme primale-duale, de la methode des deux phases, de quelques methodes de calcul de la projection du vecteur de la fonction economique, des methodes de recherche monodimensionnelle ainsi qu'un essai de traitement implicite des bornes superieures des variables
Recent advances in optical ber systems and transmission equipments play a primary role in today&#... more Recent advances in optical ber systems and transmission equipments play a primary role in today's telecommunications networks. The standardized SDH (Synchronous Digital Hierarchy) technology made the rings the most survivable architecture for designing high speed networks. Designing such networks involves not only the connguration of rings at the logical level but also the mapping of such conngurations on the physical level, i.e. ber paths. This paper deals with the problem of nding optimal clusters of nodes to be used as the basis for designing logical rings. In the simplest form, this problem is equivalent to k-equipartition, and can be modeled as a quadratic pseudo-boolean problem. We consider both linear and semideenite relaxations and present numerical results on real data from France Telecom networks with up 900 nodes, and also on randomly generated problems.
A telecommunication network is survivable if, following an arc failure, the interrupted traffic c... more A telecommunication network is survivable if, following an arc failure, the interrupted traffic canbe redirected through the network via existing excess capacity. The standard survivability problemconsists in finding the least cost investment in spare capacity to allow rerouting of a given base traffic.In this paper we consider the more involved problem of simultaneously designing the base traffic andthe spare capacity
In this talk, we present a hybrid resource allocation model for OFDMATDMA wireless networks and a... more In this talk, we present a hybrid resource allocation model for OFDMATDMA wireless networks and an algorithmic framework using a Variable Neighborhood Search metaheuristic approach for solving the problem. The model is aimed at maximizing the total bandwidth channel capacity of an uplink OFDMA-TDMA network subject to user power and subcarrier assignment constraints while simultaneously scheduling users in time. As such, the model is best suited for non-real time applications where subchannel multiuser diversity can be further exploited simultaneously in frequency and in time domains. The VNS approach is constructed upon a key aspect of the proposed model, namely its decomposition structure. Our numerical results show tight bounds for the proposed algorithm, e.g. less than 2% in most of the instances. Finally, the bounds are obtained at a very low computational cost.
... Backbone network design in communications network (Bogdanowicz, 1993); Routing in packet-swit... more ... Backbone network design in communications network (Bogdanowicz, 1993); Routing in packet-switched networks (Ribeiro and Elbaz, 1992); Virtual ... and to other packing and covering problems (see Garg and Konemann (1998); Grigoriadis and Khachiyan (1994); Leighton et al ...
In this paper, we discuss the optimal design of telecommunications networks prone to failure. The... more In this paper, we discuss the optimal design of telecommunications networks prone to failure. The problem concerns mid-range planning objectives. The purpose of the model is to give insight on the cost of protecting the network against failures by balancing the choice of a base routing of the demands and the investment in spare to protect the routing against elementary breakdowns. The problem in formulated as a large linear programming model. To exploit the structure we resort to a decomposition scheme with two nested levels. At the higher level, we propose two different schemes: a Lagrangian relaxation and a decomposition "a la Benders". The transformed problem is solved by a cutting plane method. We compare two such methods, the Cheney-Goldstein-Kelly method and the analytic center cutting plane method. The methods are tested on a set of realistic problems
A telecommunication network is survivable if, following an arc failure, the interrupted traffic c... more A telecommunication network is survivable if, following an arc failure, the interrupted traffic can be redirected through the network via existing excess capacity. The standard survivability problem consists in finding the least cost investment in spare capacity to allow rerouting of a given base traffic. In this paper we consider the more involved problem of simultaneously designing the base traffic and the spare capacity investment. If the investment costs are linear, the problem can be formulated as a large scale structured linear program that we solve using different decomposition techniques, including the analytic center cutting plane method. The global analysis is performed under the assumption of local rerouting of the traffic, i.e., the interrupted traffic creates a local demand between the end points of the broken edge. More sophisticated telecommunication network management allows to break down the interrupted traffic into its individual demand components. We do not treat ...
Recent advances in optical fiber systems and transmission equipments play a primary role in today... more Recent advances in optical fiber systems and transmission equipments play a primary role in today's telecommunications networks. The standardized SDH (Synchronous Digital Hierarchy) technology made the rings the most survivable architecture for designing high speed networks. Designing such networks involves not only the configuration of rings at the logical level but also the mapping of such configurations on the physical level, i.e. fiber paths. This paper deals with the problem of finding optimal clusters of nodes to be used as the basis for designing logical rings. In the simplest form, this problem is equivalent to k-equipartition, and can be modeled as a quadratic pseudo-boolean problem. We consider both linear and semidefinite relaxations and present numerical results on real data from France Telecom networks with up 900 nodes, and also on randomly generated problems.
Experimentation de quelques variantes de l'algorithme de Karmarkar qui ont permis d'elabo... more Experimentation de quelques variantes de l'algorithme de Karmarkar qui ont permis d'elaborer un logiciel plus performant que la version originelle. Plusieurs methodes ont ete testees; il s'agit en particulier: de la forme primale-duale, de la methode des deux phases, de quelques methodes de calcul de la projection du vecteur de la fonction economique, des methodes de recherche monodimensionnelle ainsi qu'un essai de traitement implicite des bornes superieures des variables
Recent advances in optical ber systems and transmission equipments play a primary role in today&#... more Recent advances in optical ber systems and transmission equipments play a primary role in today's telecommunications networks. The standardized SDH (Synchronous Digital Hierarchy) technology made the rings the most survivable architecture for designing high speed networks. Designing such networks involves not only the connguration of rings at the logical level but also the mapping of such conngurations on the physical level, i.e. ber paths. This paper deals with the problem of nding optimal clusters of nodes to be used as the basis for designing logical rings. In the simplest form, this problem is equivalent to k-equipartition, and can be modeled as a quadratic pseudo-boolean problem. We consider both linear and semideenite relaxations and present numerical results on real data from France Telecom networks with up 900 nodes, and also on randomly generated problems.
A telecommunication network is survivable if, following an arc failure, the interrupted traffic c... more A telecommunication network is survivable if, following an arc failure, the interrupted traffic canbe redirected through the network via existing excess capacity. The standard survivability problemconsists in finding the least cost investment in spare capacity to allow rerouting of a given base traffic.In this paper we consider the more involved problem of simultaneously designing the base traffic andthe spare capacity
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Papers by A. Lisser