143 research outputs found

    COMPONENT BASED ROUTING PROTOCOL DESIGNING METHODOLOGY FOR MANET

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    Mobile Ad Hoc Network is designed and deployed to achieve self-configuring and self-healing. MANET utilizes distributed wireless stations for relaying data packets. Every single station in the MANET can decide routing path for an incoming data packet. MANET has the most unfavorable conditions for routing path discovery due to node mobility and constant topology changes. Large variation of performance due to various environment inputs is a major impediment of implementing existing routing protocols for MANET in the battlefield. Therefore, it is a major challenge to design a routing protocol that can adapt its behavior to environment alteration. In consideration of adaptability to the environment and flexibility in protocol construction, a novel component based routing protocol methodology is proposed in this paper. Distinguished from conventional investigation of routing protocols as individual entities, this paper will firstly generalize four fundamental components for MANET routing protocols. Then, a significant component diagnosis process is proposed to detect significant component and enhance the overall performance. Finally, preliminary simulation results demonstrate the power of the component based methodology for improving overall performance and reducing performance variation. In conclusion, the evaluation and improvement at the component level is more insightful and effective than that at the protocol level. The primary contribution of the work is proposing the Component Dependence Network the first time and innovative quantitative methods are proposed to learn the structure and significant component to analyze the impact of component on performance metrics. Based on conditional independence test, hierarchical structure of Component Dependence Network can be discovered. An Inclusion and Exclusion algorithm is introduced to guarantee the minimal cut set returned for a pair of source and destination nodes. To determine the significant component, a significance indicator will be calculated based on comparing each component's impact by using a backward deriving method. Once the significant component being determined, the parameter of the significant component can be tuned to achieve the best performance. At the end, two real implementations are presented to show the achievement in performance improvement of the component dependence network, structure learning method and significant component indicator

    Dissection of Mobility Model Routing Protocols in MANET on QoS Criterion

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    Essential difficulties in Mobile Ad Hoc Networks (MANET) are routing selection and Quality of Service(QoS) support. Several different approaches have been described in the literature, and a number of performance simulations have been produced, in an attempt to tackle this challenging problem. In this study, we take a close look at the relative merits of several popular routing protocols. In this research, we looked into how changing QoS parameters in tandem with routing protocol choices affected network throughput. Typical measures for measuring network efficiency include average throughput, packet delivery ratio (PDR), average delay, and power usage. NS-3 is used to run the simulations

    Supporting Internet Access and Quality of Service in Distributed Wireless Ad Hoc Networks

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    In this era of wireless hysteria, with continuous technological advances in wireless communication and new wireless technologies becoming standardized at a fast rate, we can expect an increased interest for wireless networks, such as ad hoc and mesh networks. These networks operate in a distributed manner, independent of any centralized device. In order to realize the practical benefits of ad hoc networks, two challenges (among others) need to be considered: distributed QoS guarantees and multi-hop Internet access. In this thesis we present conceivable solutions to both of these problems. An autonomous, stand-alone ad hoc network is useful in many cases, such as search and rescue operations and meetings where participants wish to quickly share information. However, an ad hoc network connected to the Internet is even more desirable. This is because Internet plays an important role in the daily life of many people by offering a broad range of services. In this thesis we present AODV+, which is our solution to achieve this network interconnection between a wireless ad hoc network and the wired Internet. Providing QoS in distributed wireless networks is another challenging, but yet important, task mainly because there is no central device controlling the medium access. In this thesis we propose EDCA with Resource Reservation (EDCA/RR), which is a fully distributed MAC scheme that provides QoS guarantees by allowing applications with strict QoS requirements to reserve transmission time for contention-free medium access. Our scheme is compatible with existing standards and provides both parameterized and prioritized QoS. In addition, we present the Distributed Deterministic Channel Access (DDCA) scheme, which is a multi-hop extension of EDCA/RR and can be used in wireless mesh networks. Finally, we have complemented our simulation studies with real-world ad hoc and mesh network experiments. With the experience from these experiments, we obtained a clear insight into the limitations of wireless channels. We could conclude that a wise design of the network architecture that limits the number of consecutive wireless hops may result in a wireless mesh network that is able to satisfy users’ needs. Moreover, by using QoS mechanisms like EDCA/RR or DDCA we are able to provide different priorities to traffic flows and reserve resources for the most time-critical applications

    Energy-aware Ad Hoc on-demand distance vector routing protocol and optimizing the blocking problem induced in wireless Ad Hoc networks

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    The purpose of this thesis was to investigate some of the issues related to routing and medium access control protocol in ad hoc networks. In routing protocol, the goal is to tackle the power consumption problem and to present a case for using new cost energy-aware metric for Ad Hoc On-Demand Distance Vector (AODV). The idea of the new cost metric is to be able to avoid routes with a low energy capacity. By using this approach, high efficiency in energy consumption can be achieved in Ad-Hoc networks. The second goal of this thesis was to investigate the blocking problem induced by Request-to-Send/Clear-to-Send (RTS/CTS) mechanism in detail and provide a solution to overcome that problem. To do so, a new parameter is proposed by which the Medium Access control (MAC) protocol will decide when to switch between RTS/CTS mechanism (the 4-way-handshaking) and the Basic Access method (the 2-way-handshaking) in order to reduce the effect of the blocking problem in Ad Hoc networks

    Ad hoc, Modular, Probabilistic, Enhanced Routing

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.Includes bibliographical references (p. 89-91).An ad hoc network is a group of mobile nodes that autonomously establish connectivity via multi-hop wireless links, without relying on any pre-configured network infrastructure. Traditional ad hoc routing protocols use a large number of routing packets to adapt to network changes, thereby reducing the amount of bandwidth left to carry data. Moreover, they route data packets along a single path from source to destination, which introduces considerable latency for recovery from a link failure along this path. Finally, they often use the minimum hop count as a basis for routing, which does not always guarantee a high throughput. This thesis presents AMPER (Ad hoc, Modular, Probabilistic, Enhanced Routing), an ad hoc routing protocol that minimizes the routing packet overhead, allows the use of alternate paths in the event of a link outage, and employs - without loss of generality - the expected number of transmissions to make forwarding decisions. Following the design of AMPER, ns-2 is used to simulate it, evaluate it and compare it to other ad hoc routing protocols.by Abdallah W. Jabbour.S.M

    QoS in Node-disjoint Routing for Ad Hoc Networks

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    PhDA mobile ad hoc network (MANET) is a collection of mobile nodes that can communicate with each other without using any fixed infrastructure. It is necessary for MANETs to have efficient routing protocol and quality of service (QoS) mechanism to support multimedia applications such as video and voice. Node-Disjoint Multipath Routing Protocol (NDMR) is a practical protocol in MANETs: it reduces routing overhead dramatically and achieves multiple node-disjoint routing paths. Because QoS support in MANETs is important as best-effort routing is not efficient for supporting multimedia applications, this thesis presents a novel approach to provide that support. In this thesis NDMR is enhanced to provide a QoS enabled NDMR that decreases the transmission delay between source and destination nodes. A multi-rate mechanism is also implemented in the new protocol so that the NDMR QoS can minimise the overall delays. It is shown that these approaches lead to significant performance gains. A modification to NDMR is also proposed to overcome some of the limitations of the original

    A robust routing protocol for wireless mobile ad hoc networks

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