86 research outputs found
MIMODog: How to solve the problem of selfish misbehavior detection mechanism in MANETs using MIMO Technology
International audienceMobile Ad-hoc Networks (MANETs) are based on a fundamental aspect, which is the cooperative parameter. This parameter may compromise the networks. The selfish misbehaving nodes can seriously affect the network performance. Moreover, the existing mechanisms based on the monitoring process to detect the misbehaving nodes are not efficient and suffer from an important false alarm rate. These weaknesses are mainly due to the interferences and the costs of the monitoring process. In MANET based on (Single-Input Single-Output) technology, the interferences at the monitor node compromise the observation and the accuracy of the cooperation report. That is why in this paper, we focus on the MIMO (Multi-Input and Multi-Output) technology to overcome these drawbacks and to significantly improve the monitoring process. We propose a new MAC protocol called MIMODog-SPACE-MAC based on the well-known SPACE-MAC protocol. It allows the monitor node to avoid the collision during the monitoring process by adjusting the antennas weights in order to nullify the signal coming from other nodes than the monitored one. Therefore, the proposed solution contributes to significantly enhance the accuracy of the monitoring process. We show that for a MIMO network with randomly located nodes , each equipped with antennas, the achievable number of monitor nodes is . Indeed, theoretical results show that by using MIMODog-SPACE-MAC, the network can have a constant improvement on an asymptotic number of monitor nodes compared to SISO 802.11 DCF MAC
Efficient Vertical Handoffs in Wireless Overlay Networks
Mobile IP is used to keep track of location information and make the data available to the mobile device anytime, anywhere. It is designed to address the macro-mobility management, it does not address micro-level mobility issues such as handoff latency and packet loss. In this paper, we propose a mobility management scheme to handle the movements of mobile nodes among different wireless network technologies. Our scheme combines: (a) A hierarchical mobility management architecture to hide mobility of mobile nodes within the foreign domain from the home agent; (b) A handoff protocol to reduce packet loss during the transition from one cell to another; (c) The use of our proposed virtual cells in order to reduce the upward vertical handoff latency and disruption as much as possible. Our design is based on the Internet Protocol (IP) and is compatible with the Mobile IP standard (MIP). We also present simulation results showing that our handoff scheme is very fast to meet the requirements of an interactive communication session such as Internet telephony and avoiding packet loss
How MIMO cross-layer design enables QoS while detecting non-cooperative nodes in wireless multi-hop networks
In Journal of Network and Computer Applications (JNCA). DOI: 10.1016/j.jnca.2014.07.011International audienceWireless Multi-hop Networks (WMNs) are based on the cooperation between nodes. The non-cooperative (selfish) nodes can affect the quality of services (QoS) delivered by the network. The solutions proposed in literature are based on the monitoring mechanism to detect non-cooperative nodes. However, the monitoring mechanism has to tackle a significant false alarm rate. The origin of these issues is mainly related to the interferences and the costs of the monitoring mechanism. In WMNs based on Single-Input Single-Output (SISO) technology, the interferences at the monitor (detector) node can affect the assessment and the accuracy of the monitor node's observation. In this paper, we use Multi-Input and Multi-Output (MIMO) technology to tackle these drawbacks and to perform the monitoring mechanism without affecting the QoS. We propose a new MAC protocol based on the well-known SPACE-MAC protocol, named MIMODog. The collision at the monitor node can be avoided by tuning the antennas' weights. Therefore, the signal coming from other nodes than the monitored one can be nullified. Thus, this solution allows an important improvement of the accuracy of the monitor node's observation. Moreover, we propose a monitoring capacity analysis using graph theory particularly Conflict Graph (CG), and asymptotic study. We illustrate that the capacity consumed in the case of MIMODog is costly compared to SPACE-MAC, but the accuracy of the observation is better. We demonstrate that the number of monitor nodes is for a MIMO network with randomly located nodes n, each equipped with M antennas. Indeed, numerical results nlnn illustrate that by using MIMODog, the network can have a constant improvement M on an asymptotic number of monitor nodes compared to SISO 802.11 DCF MAC
A complete and efficient quality of service model for mobile ad Hoc networks
International audienc
QMOST: A QoSaware Multicast Overlay Spanning Tree Proto-col for Multimedia Applications in Mobile Ad hoc Networks
International audienc
An Efficient Source-Based Heuristic for Multicasting Multimedia Information
International audienc
Etude et conception d'algorithmes pour les réseaux mobiles et ad-hoc
Advances in mobile and wireless networks have made fourth generation networks development possible. 4G networks promote the concept of the always best connected and served (ABC&S) paradigm. The ABC&S paradigm envisages that mobile terminals will stay connected: anywhere & anytime. Our work consists on conception of a wireless overlay network structure and scheme for handoffs. The primary technical challenges in the design of a seamless handoff are: low latency and packet loss. The ad hoc networks are considered as a generalization of the wireless networks because the role of the fixed infrastructure is limited. Recently, significant progress to study QoS in the mobile ad hoc networks has been made. This thesis presents a critical vision of interesting work in this field. The strong and weak points of each proposal are exploited to carry out a complete QoS model. This model uses a QoS routing protocol to find the best paths for each flow according to its QoS requirements an admission control and reservation are used to prevent the network overload without mobility.Avec les progrĂšs rĂ©alisĂ©s dans les rĂ©seaux sans fil et mobiles, chercheurs et industriels ont dĂ©jĂ commencĂ© le dĂ©veloppement des futurs rĂ©seaux mobiles de 4Ăšme gĂ©nĂ©ration (4G). Dans cette gĂ©nĂ©ration, l'Ă©quipement terminal, de l'utilisateur recherchera en permanence le meilleur rĂ©seau d'accĂšs en fonction des besoins de l'utilisateur. Ce dernier aura plusieurs technologies d'accĂšs sans fil Ă sa disposition et souhaitera ĂȘtre connectĂ© au mieux, n'importe oĂč, n'importe quand et avec n'importe quel rĂ©seau d'accĂšs. Pour cela, les diffĂ©rentes technologies sans fil qui seront prĂ©sentes dans la 4g (UMTS, WLAN, WMAN, etc), doivent coexister. Notre travail dans cet axe de recherche consiste Ă proposer une structure hiĂ©rarchique des rĂ©seaux sans fil et des protocoles de handovers entre les diffĂ©rents systemes. Le changement de rĂ©seau doit ĂȘtre rapide et sans perte de donnĂ©es afin de garantir la transparence vis-Ă -vis des utilisateurs mobiles. Les rĂ©seaux ad hoc sont considĂ©rĂ©s comme gĂ©nĂ©ralisation ultime des rĂ©seaux sans fil car ils limitent au maximum le rĂŽle de l'infrastructure fixe. Ces derniĂšres annĂ©es, on observe des progrĂšs significatifs pour Ă©tudier la QoS dans les rĂ©seaux ad hoc mobiles. Cette thĂšse prĂ©sente une vision critique des travaux intĂ©ressants dans le domaine de la QoS dans les rĂ©seaux ad hoc. Les points forts et faibles de chaque proposition sont exploitĂ©s pour rĂ©aliser un modĂšle complet de QoS. Ce modĂšle possĂšde un protocole de routage avec QoS qui trouve la meilleure route pour chaque type de flux selon la demande. Il limite l'apparition des congestions et la surutilisation de la bande passante par un mĂ©canisme de contro^le d'admission et de rĂ©servation
A QoS-Aware Multicast Routing Protocol for Multimedia Applications in Mobile Ad hoc Networks
International audienc
An Effecient Optimization of Network Ressource Allocations Under Nonlinear Quality of Service Constraints
International audienc
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