17,997 research outputs found

    A Classification and Performance Comparison of Mobility Models for Ad Hoc Networks

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    Abstract. In mobile ad hoc network research, simulation plays an important role in determining the network characteristics and measuring performance. On the other hand, unrealistic simulation conditions may be misleading, instead of being explanatory. For this reason, constructing simulation models closer to the real circumstances is very significant. Movement behavior of mobile entities is one of the most important concepts for the realistic simulation scenarios in mo-bile ad hoc networks. In this study, we first provide a survey and a new hybrid classification of existing mobility models in the literature. We implemented the random direction and boundless simulation area models on Scalable Wireless Ad Hoc Network Simulator (SWANS) and conducted simulations of Ad Hoc On-Demand Distance Vector (AODV) protocol for these as well as the random walk and random waypoint models. Our comparative results for the mobility models are discussed on a variety of simulation settings and parameters.

    A Novel Scalable Multicast Mesh Routing Protocol for Mobile ad hoc Networks

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    In recent years the use of portable and wireless equipment is becoming more widespread, and as in many situations communication infrastructure might not be available, wireless networks such as Mobile Ad Hoc Networks (MANETs) are becoming increasingly important. A mobile ad hoc network is a collection of nodes that exchanges data over wireless paths. The nodes in this network are free to move at any time, therefore the network topology changes in an unpredictable way. Since there is no fixed infrastructure support in mobile ad hoc networks, each node functions as a host and a router. Due to mobility, continuous change in topology, limited bandwidth, and reliance on batteries; designing a reliable and scalable routing protocol for mobile ad hoc networks is a challenging task. Multicast routing protocols have been developed for routing packets in mobile ad hoc networks. Existing protocols suffer from overheads and scalability. As the number of senders, groups, and mobility speed increases, the routing overhead and the packet collision increases, and therefore the packet delivery ratio decreases. Thus none of the existing proposed multicast routing protocols perform well in every situation. In this study a novel multicast routing protocol for ad hoc networks is proposed. It is an efficient and scalable routing protocol, and named Network Sender Multicast Routing Protocol (NSMRP). NSMRP is a reactive mesh based multicast routing protocol. A central node called mesh sender (MS) is selected periodically from among the group(s) sender(s) to create one mesh in order to be used in forwarding control and data packets to all multicast group(s) member(s). One invitation message will be periodically flooded to all group(s) member(s) by MS to join the group(s). The proposed routing protocol is evaluated by simulation and compared with a well known routing protocol. The results are analyzed and conclusions are drawn

    AN AODV-based clustering and routing scheme for mobile ad hoc networks

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    A mobile ad hoc network (MANET) is a collection of wireless mobile nodes forming a temporary network without the aid of any fixed communication infrastructure. Due to limited resources, frequent network partitions and unpredictable topological changes, proactive clustering schemes incur high overheads in this environment. In this paper, we propose an on-demand, distributed clustering algorithm for MANETs based on an Ad hoc On-demand Distance Vector (AODV) routing protocol. The use of on-demand routing protocol information for clustering reduces clustering overhead because no clusters are maintained unless they are needed. The clustering algorithm’s stability was assessed using clustering metrics such as cluster head and cluster members lifetime. Based on this clustering scheme, a cluster-based routing protocol was proposed to add scalability to the AODV routing protocol. Using simulation, a comparison was made with a pure AODV protocol. Simulation experiments show that the scheme results in stable and scalable clusters and Cluster- AODV routing introduces less overhead than the pure AODV protocol without clustering1st IFIP International Conference on Ad-Hoc NetWorkingRed de Universidades con Carreras en Informática (RedUNCI

    Simulation and experimental testbed for adaptive video streaming in ad hoc networks

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    [EN] This paper presents a performance evaluation of the scalable video streaming over mobile ad hoc networks. In particular, we focus on the rate-adaptive method for streaming scalable video (H.264/SVC). For effective adaptation a new cross-layer routing protocol is introduced. This protocol provides an efficient algorithm for available bandwidth estimation. With this information, the video source adjusts its bit rate during the video transmission according to the network state. We also propose a free simulation framework that supports evaluation studies for scalable video streaming. The simulation experiments performed in this study involve the transmission of SVC streams with Medium Grain Scalability (MGS) as well as temporal scalability over different network scenarios. The results reveal that the rate-adaptive strategy helps avoid or reduce the congestion in MANETs obtaining a better quality in the received videos. Additionally, an actual ad hoc network was implemented using embedded devices (Raspberry Pi) in order to assess the performance of the proposed adaptive transmission mechanism in a real environment. Additional experiments were carried out prior to the implementation with the aim of characterizing the wireless medium and packet loss profile. Finally, the proposed approach shows an important reduction in energy consumption, as the study revealed.This paper was performed with the support of the National Secretary of Higher Education, Science, Technology and Innovation (SENESCYT)–Ecuador Government (scholarship 195-2012) and the Multimedia Communications Group (COMM) belong to the Institute of Telecommunications and Multimedia Applications (iTEAM)-Universitat Politècnica de València.Gonzalez-Martinez, SR.; Castellanos Hernández, WE.; Guzmán Castillo, PF.; Arce Vila, P.; Guerri Cebollada, JC. (2016). Simulation and experimental testbed for adaptive video streaming in ad hoc networks. Ad Hoc Networks. 52:89-105. https://doi.org/10.1016/j.adhoc.2016.07.007S891055

    Hierarchical Coverage Extension in Self-organising Wireless Network Systems

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    Future self-organising ad hoc networks (MANETs) will provide Internet access for ubiquitous wireless computing. In combination with cellular systems, e.g., B3G and 4G networks, self-organising networks will increase the coverage of cellular systems. The advantage of the so-called coverage extension is that there is no demand for extension of cost-intensive infrastructure, yet it extends network access where no coverage is provided by network operators. This paper extends studies of other related and ongoing work regarding the integration of ad hoc networks in cellular systems and coverage extension based on a complete network topology, which has been implemented for this research. A simulation study is presented in this paper with an evaluation of coverage extension methods in a free scalable hierarchical network environment and considers a trade-off discussion based on a scalable coverage area including various numbers of ad hoc nodes and base station

    Ad hoc network security and modeling with stochastic petri nets

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    Advances in wireless technology and portable computing along with demands for high user mobility have provided a major promotion toward the development of ad hoc networks. These networks feature dynamic topology, self-organization, limited bandwidth and battery power of a node. Unlike the existing commercial wireless systems and fixed infrastructure networks, they do not rely on specialized routers for path discovery and traffic routing. Security is an important issue in such networks. Typically, mobile nodes are significantly more susceptible to physical attacks than their wired counterparts. This research intends to investigate the ad hoc network routing security by proposing a performance enhanced Secure ad hoc On-demand Routing protocol (SOR). Specifically, it presents a method to embed Security Level into ad hoc on-demand routing protocols using node-disjoint multipath, and to use maximum hopcount to restrict the number of routing packets in a specific area. The proposed scheme enables the use of security as a marked factor to improve the relevance of the routes discovered by ad hoc routing protocols. It provides customizable security to the flow of routing protocol messages. In general, SOR offers an alternative way to implement security in on-demand routing protocols. Ad hoc network is too complex to allow analytical study for explicit performance expressions. This research presents a Stochastic Petri net-based approach to modeling and analysis of mobile ad hoc network. This work illustrates how this model is built as a scalable model and used to exploit the characteristics of the networks. The proposed scheme is a powerful analytical model that can be used to derive network performance much more easily than a simulation-based approach. Furthermore, the proposed model is extended to study the performance of ad hoc network security by adding multipath selection and security measurement parameters. This research gives a quantificational measurement to analyze the performance of a modified SPN model under the effect of multipath and attack of a hypothetical compromised node

    Fuzzy based load and energy aware multipath routing for mobile ad hoc networks

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    Routing is a challenging task in Mobile Ad hoc Networks (MANET) due to their dynamic topology and lack of central administration. As a consequence of un-predictable topology changes of such networks, routing protocols employed need to accurately capture the delay, load, available bandwidth and residual node energy at various locations of the network for effective energy and load balancing. This paper presents a fuzzy logic based scheme that ensures delay, load and energy aware routing to avoid congestion and minimise end-to-end delay in MANETs. In the proposed approach, forwarding delay, average load, available bandwidth and residual battery energy at a mobile node are given as inputs to a fuzzy inference engine to determine the traffic distribution possibility from that node based on the given fuzzy rules. Based on the output from the fuzzy system, traffic is distributed over fail-safe multiple routes to reduce the load at a congested node. Through simulation results, we show that our approach reduces end-to-end delay, packet drop and average energy consumption and increases packet delivery ratio for constant bit rate (CBR) traffic when compared with the popular Ad hoc On-demand Multipath Distance Vector (AOMDV) routing protocol
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