90 research outputs found

    Autonomous proximity awareness of bluetooth devices

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    This paper focuses on designing autonomous device discovery algorithms for Bluetooth networks. We first extend the conventional asymmetric Bluetooth link model to three point-to-point symmetric link models. Their performances are compared analytically. To achieve proximity awareness among a group of Bluetooth devices, three control information exchanging methods are also proposed. Combining with the three link models, this gives 9 possible variants of autonomous device discovery algorithm. A comprehensive comparative study based on these 9 variants is then carried out using Bluehoc simulator. © 2005 IEEE.published_or_final_versio

    Device Discovery in Frequency Hopping Wireless Ad Hoc Networks

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    This research develops a method for efficient discovery of wireless devices for a frequency hopping spread spectrum, synchronous, ad hoc network comprised of clustered sub-networks. The Bluetooth wireless protocol serves as the reference protocol. The development of a discovery, or outreach, method for scatternets requires the characterization of performance metrics of Bluetooth piconets, many of which are unavailable in literature. Precise analytical models characterizing the interference caused to Bluetooth network traffic by inquiring devices, the probability mass function of packet error rates between arbitrary pairs of Bluetooth networks, and Bluetooth discovery time distribution are developed. Based on the characterized performance metrics, three scatternet outreach methods are developed and compared. Outreach methods which actively inquire on a regular basis, as proposed in literature, are shown to produce lower goodput, have greater mean packet delay, require more power, and cause significant delays in discovery. By passively remaining available for outreach, each of these disadvantages is avoided

    Bluetooth Enabled Ad-hoc Networks: Performance Evaluation of a Self-healing Scatternet Formation Protocol

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    Bluetooth wireless technology is a robust short-range communications system designed for low power (10 meter range) and low cost. It operates in the 2.4 GHz Industrial Scientific Medical (ISM) band and it employs two techniques for minimizing interference: a frequency hopping scheme which nominally splits the 2.400 - 2.485 GHz band in 79 frequency channels and a time division duplex (TDD) scheme which is used to switch to a new frequency channel on 625 μs boundaries. During normal operation a Bluetooth device will be active on a different frequency channel every 625 μs, thus minimizing the chances of continuous interference impacting the performance of the system. The smallest unit of a Bluetooth network is called a piconet, and can have a maximum of eight nodes. Bluetooth devices must assume one of two roles within a piconet, master or slave, where the master governs quality of service and the frequency hopping schedule within the piconet and the slave follows the master’s schedule. A piconet must have a single master and up to 7 active slaves. By allowing devices to have roles in multiple piconets through time multiplexing, i.e. slave/slave or master/slave, the Bluetooth technology allows for interconnecting multiple piconets into larger networks called scatternets. The Bluetooth technology is explored in the context of enabling ad-hoc networks. The Bluetooth specification provides flexibility in the scatternet formation protocol, outlining only the mechanisms necessary for future protocol implementations. A new protocol for scatternet formation and maintenance - mscat - is presented and its performance is evaluated using a Bluetooth simulator. The free variables manipulated in this study include device activity and the probabilities of devices performing discovery procedures. The relationship between the role a device has in the scatternet and it’s probability of performing discovery was examined and related to the scatternet topology formed. The results show that mscat creates dense network topologies for networks of 30, 50 and 70 nodes. The mscat protocol results in approximately a 33% increase in slaves/piconet and a reduction of approximately 12.5% of average roles/node. For 50 node scenarios the set of parameters which creates the best determined outcome is unconnected node inquiry probability (UP) = 10%, master node inquiry probability (MP) = 80% and slave inquiry probability (SP) = 40%. The mscat protocol extends the Bluetooth specification for formation and maintenance of scatternets in an ad-hoc network

    Distributed algorithms for dynamic topology construction and their applications

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 155-162).(cont.) of piconets is close to optimal, and any device is a member of at most two piconets.We introduce new distributed algorithms that dynamically construct network topologies. These algorithms not only adapt to dynamic topologies where nodes join and leave, but also actively set up and remove links between the nodes, to achieve certain global graph properties. First, we present a novel distributed algorithm for constructing overlay networks that are composed of d Hamilton cycles. The protocol is decentralized as no globally-known server is required. With high probability, the constructed topologies are expanders with O(logd n) diameters and ... second largest eigenvalues. Our protocol exploits the properties of random walks on expanders. A new node can join the network in O(logd n) time with O(dlogd n) messages. A node can leave in O(1) time with O(d) messages. Second, we investigate a layered construction of the random expander networks that can implement a distributed hash table. Layered expanders can achieve degree-optimal routing at O(log n/log log n) time, where each node has O(log n) neighbors. We also analyze a self-balancing scheme for the layered networks. Third, we study the resource discovery problem, in which a network of machines discover one another by making network connections. We present two randomized algorithms to solve the resource discovery problem in O(log n) time. Fourth, we apply the insight gained from the resource discovery algorithms on general networks to ad hoc wireless networks. A Bluetooth ad hoc network can be formed by interconnecting piconets into scatternets. We present and analyze a new randomized distributed protocol for Bluetooth scatternet formation. We prove that our protocol achieves O(log n) time complexity and O(n) message complexity. In the scatternets formed by our protocol, the numberby Ching Law.Ph.D

    Mobile Ad hoc Networking: Imperatives and Challenges

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    Mobile ad hoc networks (MANETs) represent complex distributed systems that comprise wireless mobile nodes that can freely and dynamically self-organize into arbitrary and temporary, "ad-hoc" network topologies, allowing people and devices to seamlessly internetwork in areas with no pre-existing communication infrastructure, e.g., disaster recovery environments. Ad hoc networking concept is not a new one, having been around in various forms for over 20 years. Traditionally, tactical networks have been the only communication networking application that followed the ad hoc paradigm. Recently, the introduction of new technologies such as the Bluetooth, IEEE 802.11 and Hyperlan are helping enable eventual commercial MANET deployments outside the military domain. These recent evolutions have been generating a renewed and growing interest in the research and development of MANET. This paper attempts to provide a comprehensive overview of this dynamic field. It first explains the important role that mobile ad hoc networks play in the evolution of future wireless technologies. Then, it reviews the latest research activities in these areas, including a summary of MANET\u27s characteristics, capabilities, applications, and design constraints. The paper concludes by presenting a set of challenges and problems requiring further research in the future

    Scatternet Formation Protocol for Environmental Monitoring in a Smart Garden

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    [EN] The monitoring of different parameters in the smart garden environment requires thousands of nodes and actuators. They form a multi-hop communication network. The scatternets formed with Bluetooth protocol is a communication solution. However, there is no current algorithm that considers the different capabilities of the devices (sensors or actuators) and assigns a role according to these capabilities. In this paper, we present a network topology formation algorithm for role assignment and connection establishment which considers the capabilities of the devices and use slave-slave Bridge to communicate the piconets. We design the algorithms needed for this protocol and test it. We have simulated the algorithms in order to evaluate the time needed for role assignment and to establish the first connections of the piconet. The results include different scenarios composed by one or two masters and one to seven slaves. In addition, we evaluate the established connections in piconets and bridges in a real case of the smart garden sensor network. Finally, we present the changes in the piconet connections after the deployment of two nodes in an existing network.This work is partially found by the European Union with the “Fondo Europeo Agrícola de Desarrollo Rural (FEADER) – Europa invierte en zonas rurales”, the MAPAMA, and Comunidad de Madrid with the IMIDRA, under the mark of the PDR-CM 2014-2020” project number PDR18-XEROCESPED. This work has been partially supported by the "Ministerio de Economía y Competitividad" in the "Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia, Subprograma Estatal de Generación de Conocimiento" within the project under Grant TIN2017-84802-C2-1-P. This work has also been partially supported by European Union through the ERANETMED (Euromediterranean Cooperation through ERANET joint activities and beyond) project ERANETMED3-227 SMARTWATIR.Parra-Boronat, L.; Marín, J.; Mauri Ablanque, PV.; Lloret, J.; Torices, V.; Massager, A. (2018). Scatternet Formation Protocol for Environmental Monitoring in a Smart Garden. Network Protocols and Algorithms. 10(3):63-84. https://doi.org/10.5296/npa.v10i3.14122S638410

    Self-organizing Bluetooth scatternets

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 71-73).There is increasing interest in wireless ad hoc networks built from portable devices equipped with short-range wireless network interfaces. This thesis addresses issues related to internetworking such networks to form larger "scatternets." Within the constraints imposed by the emerging standard Bluetooth link layer and MAC protocol, we develop a set of online algorithms to form scatternets and to schedule point-to-point communication links. Our efficient online topology formation algorithm, called TSF (Tree Scatternet Formation), builds scatternets by connecting nodes into a tree structure that simplifies packet routing and scheduling. Unlike earlier works, our design does not restrict the number of nodes in the scatternet, and also allows nodes to arrive and leave at arbitrary times, incrementally building the topology and healing partitions when they occur. We have developed a Bluetooth simulator in ns which includes most aspects of the entire Bluetooth protocol stack. It was used to derive simulation results that show that TSF has low latencies in link establishment, tree formation and partition healing. All of these grow logarithmically with the number of nodes in the scatternet. Furthermore, TSF generates tree topologies where the average path length between any node pair grows logarithmically with the size of the scatternet. Our scheduling algorithm, called TSS (Tree Scatternet Scheduling), takes advantage of the tree structure of the scatternets constructed by TSF. Unlike previous works, TSS coordinates one-hop neighbors effectively to increase the overall performance of the scatternet. In addition, TSS is robust and responsive to network conditions, adapting the inter-piconet link schedule effectively based on varying workload conditions. We demonstrate that TSS has good performance on throughput and latency under various traffic loads.by Godfrey Tan.S.M

    Distributed construction and maintenance of bandwidth-efficient bluetooth scatternets

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    Cataloged from PDF version of article.Bluetooth is currently the mainstream technology used for short range wireless communication due to its low power and low cost properties. In order to communicate, Bluetooth enabled devices can form networks called piconets, which consist of at most eight members. To construct larger Bluetooth networks, which are called scatternets, any number of piconets can be combined. Although piconet construction process is standardized by Bluetooth Special Interest Group, scatternet construction policies and algorithms are not yet clarified. There have been many solution proposals for the scatternet construction problem each of which focuses on different aspects of it like the efficiency of the construction algorithm, ease of routing in the resulting scatternet and number of piconets that constitute it. Although various considerations came into picture, bandwidth efficiency of the resulting scatternet topology, which depends on the placement of nodes and communication demand among them, did not take much attention. In this thesis, we provide a distributed and adaptive algorithm that constructs a scatternet and based on collected traffic flow information, modifies it to minimize the overall bandwidth usage. As consequences of efficient use of available bandwidth, reduce in average latency and total energy consumption as well as increase in available bandwidth for new communication demand are also aimed. Moreover, performance of the proposed algorithm is presented, based on the evaluation criteria described.Tekkalmaz, MetinM.S
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