RIVANO , Hervé

This thesis deals with fundamental combinatorial optimization problems yielded by structural and algorithmic models of optical backbone networks design. Telecommunication operators require the optimization of these networks and a guaranted efficient use of the resources they deploy.We give a new model for multifiber WDM optical networks....

We consider the problem of finding a lightpath assignment for a given set of communication requests on a multifiber WDM optical network with wavelength translators. Given such a network, and w the number of wavelengths available on each fiber, k the number of fiber per link and c the number of partial wavelength translation available on each...

Nous considérons le problème du routage optique d'un ensemble donné de requêtes de communications dans un réseau WDM multifibres avec conversion partielle. Étant donné un tel réseau disposant de w longueurs d'onde par fibre, k fibres par lien et c conversions possibles par nœud du réseau, le problème revient à décider s'il est possible de...

There is an increasing interest in using Wireless Mesh Networks (WMNs) as broadband backbone for next-generation wireless networking. WMNs is a scalable and cost-effective solution. Industrial standards groups are revisiting the existing protocols and they work enhanced specifications for WMNs. Wireless Mesh Networks (WMNs) are cost-effective...

This article presents a mathematical model that results in a low-cost network design to satisfy a set of point-to-point demands that arrive and leave the network along of time. It considers the problem of routing working traffic and assigning wavelengths in an all-optical network avoiding if possible that wavelengths assignment changes and flow...

We consider the problem of finding a lightpath assignment for a given set of communication requests on a multifiber WDM optical network with wavelength translators. Given such a network and w, the number of wavelengths available on each fiber, k, the number of fibers per link, and c, the number of partial wavelength translations available on...

Ad hoc networking specific challenges foster a strong research effort on efficient protocols design. Routing protocols based on a self-organized structure have been studied principally for the robustness and the scalability they provide. On the other hand, self-organization schemes may decrease the network capacity since they concentrate the...

Dans un réseau radio maillé multi-saut où tous les routeurs émettent une quantité de trafic vers la passerelle, le goulot d'étranglement autour de cette passerelle représente la majeure contrainte. Ceci limite les performances du réseau, particulièrement la capacité du réseau. Dans ce travail, nous étudions l'ordonnancement autour de la...

Ad hoc networking specific challenges foster a strong research effort on efficient protocols design. Routing protocols based on a self-organized structure have been studied principally for the robustness and the scalability they provide. On the other hand, self-organization schemes may decrease the network capacity since they concentrate the...

Dans cet article, nous étudions la capacité des réseaux radio maillés dédiés à l'accès à Internet. Nous nous plaçons dans l'hypothèse d'un réseau synchrone fonctionnant en régime permanent où les transmissions partagent un même canal radio. Le routage et l'ordonnancement des transmissions ont un impact majeur sur la capacité fournie aux...

In this paper, we address the routing and call scheduling problem in which one has to find a minimum-length schedule of selected links in a TDMA (Time Division Multiple Access) based wireless network. As we deal with a multi-hop networks, these selected links represent a routing solution (paths) providing enough capacity to achieve the routers...

Les réseaux ad hoc tirent parti de la collaboration des noeuds pour acheminer des informations. Si de nombreuses approches ont vu le jour, la problématique du routage demeure un point crucial. Deux approches se détachent : une première résidant dans une visionà plat du réseau et une seconde, plus récente, où le routage repose sur une...

La capacité d'un réseau ad hoc sans fil passe mal à l'échelle lorsque le nombre $N$ de noeuds du réseau augmente. Si chaque noeud choisit un interlocuteur parmi les autres noeuds, le débit avec lequel les noeuds peuvent communiquer doit tendre vers $0$ au moins en $\mathcal{O}\left(1/\sqrt{N}\right)$ lorsque $N$ tend vers l'infini. Le problème...

In this paper, we address the problem of bandwidth allocation and routing in wireless networks. A first model of this problem is known as the Round Weighting Problem (RWP) in which a weight is assigned to the set of rounds, i.e. a set of pairwise non-interfering links. We present a new formulation that forgets about the routing and concentrate...

We study the dipath-coloring problem in bounded degree and treewidth symmetric digraphs, in which one needs to color the dipaths with a minimum number of colors, in such a way that dipaths using the same arc have different colors. This classic combinatorial problem finds applications in the minimizat- ion of the number of wavelengths in...

Assuming a given network topology and a routing protocol, this work is focused on the capacity evaluation of routing protocols based on either a self-organization scheme or a flat approach. To reach this goal, we propose to use linear-programming formulation to model radio resource sharing as linear constraints. Four models are detailed to...

The specific challenges of multihop wireles networks lead to a strong research effort on efficient protocols design where the offered capacity is a key objective. More specifically, routing strategy largely impacts the network capacity, i.e. the throughput offered to each flow. In this work, we propose a complete framework to compute the upper...

The capacity of a multi-hop wireless network is the traffic payload that it can transport. This is a prominent quality of service issue, particularly in the highly constrained settings of 802.11 wireless mesh network. In this paper, we consider two complementary definitions of the capacity. A network-wise capacity is defined as the sum of the...

In this paper, we investigate on minimizing the energy consumption of a fixed broadband wireless network through a joint optimization of data routing and radio configuration. The network is modeled by a digraph in which the nodes represent radio base stations and the arcs denote radio links. Under this scenario, a power-efficient configuration...

In this work, we investigate on determining feasible radio configurations in fixed broadband wireless networks, focusing on power efficiency. Under this scenario, a power-efficient configuration can be characterized by a modulation constellation size and a transmission power level. Every link holds a set of power-efficient configurations, each...

In this paper, we address the problem of computing the transport capacity of Wireless Mesh Networks dedicated to Internet access. Routing and transmission scheduling have a major impact on the capacity provided to the clients. A cross- layer optimization of these problems allows the routing to take into account contentions due to radio...

Ces travaux s'attachent à définir le problème du routage optique multifibres ainsi qu'une modélisation en terme de multiflot entier. Cette modélisation permet d'envisager de bonnes approximations et heuristiques.

In this paper, we address the problem of computing the transport capacity of Wireless Mesh Networks (WMNs) dedicated to Internet access. Routing and transmission scheduling have a major impact on the capacity provided to the clients. A cross-layer optimization of these problems allows the routing to take into account contentions due to radio...

In this work, we investigate on minimizing the energy consumption of a wireless backhaul communication network through a joint optimization of data routing and radio configuration. The backhaul network is modeled by a digraph in which the nodes represent radio base stations and the arcs denote radio links. According to the scenario under...