3,597 research outputs found

    Vertex-linked infrastructure for ad hoc networks

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    An ad hoc network is composed of geographically dispersed nodes that may move arbitrarily and communicate with each other without the support of a stationary infrastructure. Compared with a wireless network with a stationary infrastructure, such as a cellular network, an ad hoc network is inherently less efficient. Therefore, a number of proposals have been made to develop a quasi-stationary infrastructure for ad hoc networks. However, the dynamic nature of ad hoc networks makes it very costly to maintain such an infrastructure. This article proposes a Vertex-Linked Infrastructure (VLI) for ad hoc networks. This novel approach uses an easily deployable, survivable, wired infrastructure as a backbone of the ad hoc network, thus realizing the advantages of an infrastructure in wireless communications, but without the overhead due to maintaining such an infrastructure.published_or_final_versio

    Optimal Paths on the Space-Time SINR Random Graph

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    We analyze a class of Signal-to-Interference-and-Noise-Ratio (SINR) random graphs. These random graphs arise in the modeling packet transmissions in wireless networks. In contrast to previous studies on the SINR graphs, we consider both a space and a time dimension. The spatial aspect originates from the random locations of the network nodes in the Euclidean plane. The time aspect stems from the random transmission policy followed by each network node and from the time variations of the wireless channel characteristics. The combination of these random space and time aspects leads to fluctuations of the SINR experienced by the wireless channels, which in turn determine the progression of packets in space and time in such a network. This paper studies optimal paths in such wireless networks in terms of first passage percolation on this random graph. We establish both "positive" and "negative" results on the associated time constant. The latter determines the asymptotics of the minimum delay required by a packet to progress from a source node to a destination node when the Euclidean distance between the two tends to infinity. The main negative result states that this time constant is infinite on the random graph associated with a Poisson point process under natural assumptions on the wireless channels. The main positive result states that when adding a periodic node infrastructure of arbitrarily small intensity to the Poisson point process, the time constant is positive and finite

    A secure and lightweight ad-hoc routing algorithm for personal networks

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    Over the past few years, there has been increasing interest in utilizing Personal Area Networks (PANs) to offer users innovative and personalized services. This interest is a consequence of the widespread use of mobile devices such as laptops, mobile phones, PDAs, digital cameras, wireless headsets, etc. to carry out a variety of user-centric tasks. The PAN itself is built upon an ad-hoc network where devices trust their neighbors to route their packets. The cooperative nature of ad-hoc networks allows malicious nodes to easily cripple the network by inserting false route information, replaying old messages, modifying messages of other nodes, etc. An applicable area still under research, and the focus of this paper, is secure routing protocols for ad-hoc networks. To achieve availability in the PAN, the routing protocol used must be robust against both dynamically changing topology and malicious attacks. However, the heterogeneous nature of Personal Network (PN) devices means that traditional security mechanisms are too resource intensive to be sufficient by themselves. This paper describes a new ad-hoc secure routing protocol for Personal Networks (PNs), suitable in a limited multi-hop scenario. This protocol is based on ADOV and relies on efficient cryptographic primitives to safeguard the security and privacy of PN users. Following that, a number of attacks in the area of ad-hoc networks are discussed, and it is shown that the new algorithm protects against multiple un-coordinated active attackers, in spite of compromised nodes in the network

    Autonomous deployment and repair of a sensor network using an unmanned aerial vehicle

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    We describe a sensor network deployment method using autonomous flying robots. Such networks are suitable for tasks such as large-scale environmental monitoring or for command and control in emergency situations. We describe in detail the algorithms used for deployment and for measuring network connectivity and provide experimental data we collected from field trials. A particular focus is on determining gaps in connectivity of the deployed network and generating a plan for a second, repair, pass to complete the connectivity. This project is the result of a collaboration between three robotics labs (CSIRO, USC, and Dartmouth.)

    A Graph-Based Approach to Address Trust and Reputation in Ubiquitous Networks

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    The increasing popularity of virtual computing environments such as Cloud and Grid computing is helping to drive the realization of ubiquitous and pervasive computing. However, as computing becomes more entrenched in everyday life, the concepts of trust and risk become increasingly important. In this paper, we propose a new graph-based theoretical approach to address trust and reputation in complex ubiquitous networks. We formulate trust as a function of quality of a task and time required to authenticate agent-to-agent relationship based on the Zero-Common Knowledge (ZCK) authentication scheme. This initial representation applies a graph theory concept, accompanied by a mathematical formulation of trust metrics. The approach we propose increases awareness and trustworthiness to agents based on the values estimated for each requested task, we conclude by stating our plans for future work in this area
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