A simulated annealing algorithm for router nodes placement problem in Wireless Mesh Networks

Mesh router nodes placement is a central problem in Wireless Mesh Networks (WMNs). An efficient placement of mesh router nodes is indispensable for achieving network performance in terms of both network connectivity and user coverage. Unfortunately the problem is computationally hard to solve to optimality even for small deployment areas and a small number of mesh router nodes. As WMNs are becoming an important networking infrastructure for providing cost-efficient broadband wireless connectivity, researchers are paying attention to the resolution of the mesh router placement problem through heuristic approaches in order to achieve near optimal, yet high quality solutions in reasonable time. In this work we propose and evaluate a simulated annealing (SA) approach to placement of mesh router nodes in WMNs. The optimization model uses two maximization objectives, namely, the size of the giant component in the network and user coverage. Both objectives are important to deployment of WMNs; the former is crucial to achieve network connectivity while the later is an indicator of the QoS in WMNs. The SA approach distinguishes for its simplicity yet its policy of neighborhood exploration allows to reach promising areas of the solution space where quality solutions could be found. We have experimentally evaluated the SA algorithm through a benchmark of generated instances, varying from small to large size, and capturing different characteristics of WMNs such as topological placements of mesh clients. The experimental results showed the efficiency of the annealing approach for the placement of mesh router nodes in WMNs.Peer ReviewedPostprint (author's final draft

Urban Infrastructure Deployment for Wireless On-Street Parking Sensor Networks

International audienceThe deployment strategy of wireless applications in metropolitan areas is essential for their efficiency and functionality. In this paper, we introduce and study a deployment strategy for wireless on-street parking sensor networks. We define a multiple-objective problem in our analysis, and solve it with two real-world street parking maps. We present the results on the tradeoff among minimum energy consumption, sensing information delay and the amount of deployed mesh routers and Internet gateways, i.e., the cost of city infrastructure. These results yield engineering insights for appraising and deploying city mesh infrastructure to provide smart parking services to urban users. We also analyze these tradeoffs to see how different urban layouts affect the optimal solutions

Enforcing High-Performance Operation of Multi-hop Wireless Networks With MIMO Relays

Abstract-In multi-hop wireless networks where links are prone to be broken or degraded, it is important to guarantee the network connectivity as well as satisfy the performance requirements. Observing the promising features of MultipleInput Multiple-Output (MIMO) techniques for improving the transmission capacity and reliability, in this paper, we make the very first attempt to deploy MIMO nodes as relays to assist weak links in wireless networks, with the aim of reducing the number of relay nodes and providing performance provisioning. We identify the specific constraints of MIMO relay nodes for assisting weak links, and take advantage of the MIMO ability to flexibly select among different transmission strategies. The constrains and flexibility, however, make the MIMO deployment problem different from conventional single-antenna deployment schemes and much more challenging. Based on the constraints, we formulate the MIMO relay deployment problem, and provide a polynomial-time approximation scheme (PTAS) algorithm, as well as a distributed heuristic algorithm. The performance of the proposed algorithms is evaluated through simulations and demonstrated to be very effective

Solution methods for planning problems in wireless mesh networks

Ankara : The Department of Industrial Engineering and the Graduate School of Engineering and Science of Bilkent University, 2012.Thesis (Master's) -- Bilkent University, 2012.Includes bibliographical references leaves 41-43.Wireless Mesh Networks (WMNs) consist of a finite number of radio nodes. A subset of these nodes, called gateways, has wired connection to the Internet and the non-gateway nodes transmit their traffic to a gateway node through the wireless media in a multi-hop fashion. Wireless communication signals that propagate simultaneously within the same frequency band may interfere with one another at a receiving node and may therefore prevent successful transmission of data. In order to circumvent this problem, nodes on the network can be configured to receive and send signals in different time slots and through different frequency bands. Therefore, a transmission slot can be defined as a pair of a certain frequency band and a specific time slot. In addition, by adjusting the power level of a radio node, its transmission range can be modified. Given a wireless mesh network with fixed node locations, demand rate at each node, and maximum power level for each node, we study the problem of carrying the traffic of each node to the Internet through the network. Our goal is to allocate capacities in proportion to the demand of each node in such a way that the minimum ratio is maximized. We propose a mixed integer linear programming (MILP) formulation to select a given number of gateway locations among the nodes in the network, to determine the routing of the traffic of each node through the gateway nodes, to assign transmission slots to each node in order to ensure no interference among wireless signals, and to determine the transmission power levels. In our study, we adopt the physical interference model, instead of the protocol interference, since this is more realistic. Since MILP formulation becomes computationally inefficient for larger instances; we developed several different approaches. Then, we proposed a combinatorial optimization model which successfully solves most of the instances. We tested our models and methods in several data sets, and results are presented.Özdemir, GörkemM.S

A Socio-inspired CALM Approach to Channel Assignment Performance Prediction and WMN Capacity Estimation

A significant amount of research literature is dedicated to interference mitigation in Wireless Mesh Networks (WMNs), with a special emphasis on designing channel allocation (CA) schemes which alleviate the impact of interference on WMN performance. But having countless CA schemes at one's disposal makes the task of choosing a suitable CA for a given WMN extremely tedious and time consuming. In this work, we propose a new interference estimation and CA performance prediction algorithm called CALM, which is inspired by social theory. We borrow the sociological idea of a "sui generis" social reality, and apply it to WMNs with significant success. To achieve this, we devise a novel Sociological Idea Borrowing Mechanism that facilitates easy operationalization of sociological concepts in other domains. Further, we formulate a heuristic Mixed Integer Programming (MIP) model called NETCAP which makes use of link quality estimates generated by CALM to offer a reliable framework for network capacity prediction. We demonstrate the efficacy of CALM by evaluating its theoretical estimates against experimental data obtained through exhaustive simulations on ns-3 802.11g environment, for a comprehensive CA test-set of forty CA schemes. We compare CALM with three existing interference estimation metrics, and demonstrate that it is consistently more reliable. CALM boasts of accuracy of over 90% in performance testing, and in stress testing too it achieves an accuracy of 88%, while the accuracy of other metrics drops to under 75%. It reduces errors in CA performance prediction by as much as 75% when compared to other metrics. Finally, we validate the expected network capacity estimates generated by NETCAP, and show that they are quite accurate, deviating by as low as 6.4% on an average when compared to experimentally recorded results in performance testing

Métriques de routage dans les réseaux maillés sans fil

Ces dernières années, les technologies sans fil ont connu un essor fulgurant. Elles ont permis la mise en place de réseaux sans fil à hautes performances. Les réseaux maillées sans fil (RMSF) sont une nouvelle génération de réseaux sans fil qui offrent des débits élevés par rapport aux réseaux Wi-Fi (Wireless Fidelity) classiques et aux réseaux ad-hoc. Ils présentent de nombreux avantages telles que leur forte tolérance aux pannes, leur robustesse, leur faible coût etc. Les routeurs des RMSF peuvent disposer de plusieurs interfaces radio et chaque interface peut opérer sur plusieurs canaux distincts, c’est des RMSF multiples-radios, multiples-canaux. Ce type de réseau peut accroître de manière considérable les performances des RMSF. Cependant plusieurs problèmes subsistent et doivent être résolus notamment celui du routage. Le routage dans les RMSF demeure un défi majeur. Le but des protocoles de routage est de trouver les meilleures routes i.e. des routes qui maximisent les débits et minimisent les délais, lors de l’acheminement du trafic. La qualité des routes dans les RMSF peut être fortement affectée par les interférences, les collisions, les congestions etc. Alors les protocoles doivent être en mesure de détecter ces problèmes pour pouvoir en tenir compte lors de la sélection des routes. Plusieurs études ont été dédiées aux métriques et aux protocoles de routage dans les RMSF afin de maximiser les performances de celles ci. Mais la plupart ne prennent pas en considération toutes les contraintes telles que les interférences, le problème des stations cachées etc. Ce mémoire propose une nouvelle métrique de routage pour RMSF. Nous avons mis en place une nouvelle métrique de routage pour RMSF appelée MBP (Metric Based on Probabilities). Cette métrique est destinée aux RMSF mono-radio ou multiples-radios. Elle permet d’éviter les routes à forte ii interférence. Les résultats des simulations ont montré que MBP présente des améliorations par rapport à certaines métriques : ETT, WCETT et iAWARE qui sont connues dans le domaine.In recent years, wireless technologies have developed sharply. They allow the establishment of high performance wireless networks. Wireless Mesh Networks (WMNs) is a new generation of wireless networks that offer high throughput compared to classical Wi-Fi (Wireless Fidelity) or ad-hoc networks. WMNs have attracted significant research due to their features that include dynamic self organization, self configuration, easy maintenance and low cost. WMNs nodes can be equipped with multiples-radios and multiples-channels. This type of network can increase significantly the performance of WMNs. However, several problems must be solved including routing in WMNs. Routing in WMNs is a great challenge. The main goal of routing protocols is to find best paths i.e. paths that maximize throughputs and minimize delays when transmitting packets. Route quality can be strongly affected by interference, collisions, congestions etc. Then protocols should be able to detect these problems and take them into account during route selection. We propose a new routing metric for WMNs, called MBP that captures the impact of intra-flow and inter-flow interference in multi-radio, multi-channel networks. Results show that MBP has better performances than some existing and popular metrics like ETT, WCETT and iAWARE