9 research outputs found

    A Novel Scheme for High scale IVC and RVC Over Bluetooth

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    Vehicular Ad-Hoc Network (VANET) is a form of Mobile ad-hoc network, to provide communications among nearby vehicles called inter-vehicle communication (IVC) and between vehicles and nearby fixed equipment called roadside-vehicle communication (RVC). In VANET, or Intelligent Vehicular Ad-Hoc Networking, defines an intelligent way of using Vehicular Networking. In VANET integrates on multiple ad-hoc networking technologies such as WiFi, IEEE 802.16, Blue-tooth, IRA etc. for easy, accurate, effective and simple communication between vehicles on dynamic mobility. For configuring the vehicle with a unique address, there is a need for address reconfigurations depending on the mobility patterns; we have presented a centralized addressing scheme for VANET using Blue-tooth. By building up a P2P (Per to Per) overlay network on top of VANETs physical infrastructure, we effectively integrated P2P network’s advantage on sustaining highly dynamic network into the design of VANET routing protocol. By deploying passive VANET routing algorithms with innovative P2P routing mechanisms, we propose two concepts behind the same Single Hopping and Multi Hopping technique. This project investigates the feasibility of having a Vehicular Ad-Hoc Network (VANET) / Mobile Ad-hoc Network (MANET) routing over Bluetooth. Contrary to this approach, most papers of MANET take WiFi as their underlying technology with the aim to expand the already existing internet, and it has fifty meters plus signal range. With the rapid growth in popularity, Bluetooth is being used in increasingly diverse ways to act as a bridge of communication between different hardware. This project develops on this by testing the effectiveness of a Bluetooth routing system with a fully working router implementation on real mobile phones

    PAN: Providing Reliable Storage in Mobile Ad Hoc Networks with Probabilistic Quorum Systems

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    Reliable storage of data with concurrent read/write accesses (or query/update) is an ever recurring issue in distributed settings. In mobile ad hoc networks, the problem becomes even more challenging due to highly dynamic and unpredictable topology changes. It is precisely this unpredictability that makes probabilistic protocols very appealing for such environments. Inspired by the principles of probabilistic quorum systems, we present a Probabilistic quorum system for Ad hoc Networks (PAN), a collection of protocols for the reliable storage of data in mobile ad hoc networks. Our system behaves in a predictable way due to the gossip-based diffusion mechanism applied for quorum accesses, and the protocol overhead is reduced by adopting an asymmetric quorum construction. We present an analysis of our PAN system, in terms of both reliability and overhead, which can be used to fine tune protocol parameters to obtain the desired tradeoff between efficiency and fault tolerance. We confirm the predictability and tunability of PAN through simulations with ns-2

    Data Replication for Improving Data Accessibility in Ad Hoc Networks

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    In ad hoc networks, due to frequent network partition, data accessibility is lower than that in conventional fixed networks. In this paper, we solve this problem by replicating data items on mobile hosts. First, we propose three replica allocation methods assuming that each data item is not updated. In these three methods, we take into account the access frequency from mobile hosts to each data item and the status of the network connection. Then, we extend the proposed methods by considering aperiodic updates and integrating user profiles consisting of mobile users\u27\u27 schedules, access behavior, and read/write patterns. We also show the results of simulation experiments regarding the performance evaluation of our proposed method

    PILOT: ProbabilistIc Lightweight grOup communication sysTem for Mobile Ad Hoc Networks

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    Providing reliable group communication is an ever recurring issue in distributed settings. In mobile ad hoc networks, this issue becomes more significant since all nodes act as peers, while the issue gets even more challenging due to highly dynamic and unpredictable topology changes. In order to overcome these difficulties, we deviate from the conventional point of view, i.e., we "fight fire with fire", by exploiting the nondeterministic nature of ad hoc networks. Inspired by the principles of gossip mechanisms and probabilistic quorum systems, we present in this paper a ProbabilistIc Lightweight grOup communication sysTem (PILOT) for ad hoc networks, a two layer system consisting of a set of protocols for reliable multicasting and data sharing in mobile ad hoc networks. The system performance, in terms of both reliability (fault tolerance) and efficiency (overhead), is predictable and controllable. We present an analysis of PILOT performance, which is used to fine tune protocol parameters to obtain the desired tradeoff between reliability and efficiency. We confirm the predictability and tunability of PILOT through simulations with ns-2

    Balancing the Trade-Offs between Query Delay and Data Availability in MANETs

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    Power control and scheduling for wireless data communications

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    Master'sMASTER OF ENGINEERIN

    Naming and Address Resolution in Heterogeneous Mobile Ad hoc Networks

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    This doctoral thesis deals with naming and address resolution in heterogeneous networks to be used in disaster scenarios. Such events could damage the communication infrastructure in parts or completely. To reestablish communication, Mobile Ad hoc Networks (MANETs) could be used where central entities have to be eliminated broadly. The main focus of the thesis lies on two things: an addressing scheme that helps to find nodes, even if they frequently change the subnet and the local addressing, by introducing an identifying name layer; and a MANET-adapted substitution of the Domain Name System (DNS) in order to resolve node identities to changing local addresses. We present our solution to provide decentralized name resolution based on different underlying routing protocols embedded into an adaptive routing framework. Furthermore, we show how this system works in cascaded networks and how to extend the basic approach to realize location-aware service discovery.Auch im Buchhandel erhältlich: Naming and Address Resolution in Heterogeneous Mobile Ad hoc Networks / Sebastian Schellenberg Ilmenau : Univ.-Verl. Ilmenau, 2016. - xvi, 177 Seiten ISBN 978-3-86360-129-4 Preis (Druckausgabe): 17,60

    Resource-efficient strategies for mobile ad-hoc networking

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    The ubiquity and widespread availability of wireless mobile devices with ever increasing inter-connectivity (e. g. by means of Bluetooth, WiFi or UWB) have led to new and emerging next generation mobile communication paradigms, such as the Mobile Ad-hoc NETworks (MANETs). MANETs are differentiated from traditional mobile systems by their unique properties, e. g. unpredictable nodal location, unstable topology and multi-hop packet relay. The success of on-going research in communications involving MANETs has encouraged their applications in areas with stringent performance requirements such as the e-healthcare, e. g. to connect them with existing systems to deliver e-healthcare services anytime anywhere. However, given that the capacity of mobile devices is restricted by their resource constraints (e. g. computing power, energy supply and bandwidth), a fundamental challenge in MANETs is how to realize the crucial performance/Quality of Service (QoS) expectations of communications in a network of high dynamism without overusing the limited resources. A variety of networking technologies (e. g. routing, mobility estimation and connectivity prediction) have been developed to overcome the topological instability and unpredictability and to enable communications in MANETs with satisfactory performance or QoS. However, these technologies often feature a high consumption of power and/or bandwidth, which makes them unsuitable for resource constrained handheld or embedded mobile devices. In particular, existing strategies of routing and mobility characterization are shown to achieve fairly good performance but at the expense of excessive traffic overhead or energy consumption. For instance, existing hybrid routing protocols in dense MANETs are based in two-dimensional organizations that produce heavy proactive traffic. In sparse MANETs, existing packet delivery strategy often replicates too many copies of a packet for a QoS target. In addition, existing tools for measuring nodal mobility are based on either the GPS or GPS-free positioning systems, which incur intensive communications/computations that are costly for battery-powered terminals. There is a need to develop economical networking strategies (in terms of resource utilization) in delivering the desired performance/soft QoS targets. The main goal of this project is to develop new networking strategies (in particular, for routing and mobility characterization) that are efficient in terms of resource consumptions while being effective in realizing performance expectations for communication services (e. g. in the scenario of e-healthcare emergency) with critical QoS requirements in resource-constrained MANETs. The main contributions of the thesis are threefold: (1) In order to tackle the inefficient bandwidth utilization of hybrid service/routing discovery in dense MANETs, a novel "track-based" scheme is developed. The scheme deploys a one-dimensional track-like structure for hybrid routing and service discovery. In comparison with existing hybrid routing/service discovery protocols that are based on two-dimensional structures, the track-based scheme is more efficient in terms of traffic overhead (e. g. about 60% less in low mobility scenarios as shown in Fig. 3.4). Due to the way "provocative tracks" are established, the scheme has also the capability to adapt to the network traffic and mobility for a better performance. (2) To minimize the resource utilization of packet delivery in sparse MANETs where wireless links are intermittently connected, a store-and-forward based scheme, "adaptive multicopy routing", was developed for packet delivery in sparse mobile ad-hoc networks. Instead of relying on the source to control the delivery overhead as in the conventional multi-copy protocols, the scheme allows each intermediate node to independently decide whether to forward a packet according to the soft QoS target and local network conditions. Therefore, the scheme can adapt to varying networking situations that cannot be anticipated in conventional source-defined strategies and deliver packets for a specific QoS targets using minimum traffic overhead. ii (3) The important issue of mobility measurement that imposes heavy communication/computation burdens on a mobile is addressed with a set of resource-efficient "GPS-free" soluti ons, which provide mobility characterization with minimal resource utilization for ranging and signalling by making use of the information of the time-varying ranges between neighbouring mobile nodes (or groups of mobile nodes). The range-based solutions for mobility characterization consist of a new mobility metric for network-wide performance measurement, two velocity estimators for approximating the inter-node relative speeds, and a new scheme for characterizing the nodal mobility. The new metric and its variants are capable of capturing the mobility of a network as well as predicting the performance. The velocity estimators are used to measure the speed and orientation of a mobile relative to its neighbours, given the presence of a departing node. Based on the velocity estimators, the new scheme for mobility characterization is capable of characterizing the mobility of a node that are associated with topological stability, i. e. the node's speeds, orientations relative to its neighbouring nodes and its past epoch time. iiiBIOPATTERN EU Network of Excellence (EU Contract 508803
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