85 research outputs found

    Can Bluetooth Succeed as a Large-Scale Ad Hoc Networking Technology?

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    We investigate issues that Bluetooth may face in evolving from a simple wire replacement to a large-scale ad hoc networking technology. We do so by examining the efficacy of Bluetooth in establishing a connected topology, which is a basic requirement of any networking technology. We demonstrate that Bluetooth experiences some fundamental algorithmic challenges in accomplishing this seemingly simple task. Specifically, deciding whether there exists at least one connected topology that satisfies the Bluetooth constraints is NP-hard. Several implementation problems also arise due to the internal structure of the Bluetooth protocol stack. All these together degrade the performance of the network, or increase the complexity of operation. Given the availability of efficient substitute technologies, Bluetooth’s use may end up being limited to small ad hoc networks

    A PROTOCOL SUITE FOR WIRELESS PERSONAL AREA NETWORKS

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    A Wireless Personal Area Network (WPAN) is an ad hoc network that consists of devices that surround an individual or an object. Bluetooth® technology is especially suitable for formation of WPANs due to the pervasiveness of devices with Bluetooth® chipsets, its operation in the unlicensed Industrial, Scientific, Medical (ISM) frequency band, and its interference resilience. Bluetooth® technology has great potential to become the de facto standard for communication between heterogeneous devices in WPANs. The piconet, which is the basic Bluetooth® networking unit, utilizes a Master/Slave (MS) configuration that permits only a single master and up to seven active slave devices. This structure limitation prevents Bluetooth® devices from directly participating in larger Mobile Ad Hoc Networks (MANETs) and Wireless Personal Area Networks (WPANs). In order to build larger Bluetooth® topologies, called scatternets, individual piconets must be interconnected. Since each piconet has a unique frequency hopping sequence, piconet interconnections are done by allowing some nodes, called bridges, to participate in more than one piconet. These bridge nodes divide their time between piconets by switching between Frequency Hopping (FH) channels and synchronizing to the piconet\u27s master. In this dissertation we address scatternet formation, routing, and security to make Bluetooth® scatternet communication feasible. We define criteria for efficient scatternet topologies, describe characteristics of different scatternet topology models as well as compare and contrast their properties, classify existing scatternet formation approaches based on the aforementioned models, and propose a distributed scatternet formation algorithm that efficiently forms a scatternet topology and is resilient to node failures. We propose a hybrid routing algorithm, using a bridge link agnostic approach, that provides on-demand discovery of destination devices by their address or by the services that devices provide to their peers, by extending the Service Discovery Protocol (SDP) to scatternets. We also propose a link level security scheme that provides secure communication between adjacent piconet masters, within what we call an Extended Scatternet Neighborhood (ESN)

    Adaptive Capacity Management in Bluetooth Networks

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    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

    Low-Power Wireless for the Internet of Things: Standards and Applications: Internet of Things, IEEE 802.15.4, Bluetooth, Physical layer, Medium Access Control,coexistence, mesh networking, cyber-physical systems, WSN, M2M

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    International audienceThe proliferation of embedded systems, wireless technologies, and Internet protocols have enabled the Internet of Things (IoT) to bridge the gap between the virtual and physical world through enabling the monitoring and actuation of the physical world controlled by data processing systems. Wireless technologies, despite their offered convenience, flexibility, low cost, and mobility pose unique challenges such as fading, interference, energy, and security, which must be carefully addressed when using resource-constrained IoT devices. To this end, the efforts of the research community have led to the standardization of several wireless technologies for various types of application domains depending on factors such as reliability, latency, scalability, and energy efficiency. In this paper, we first overview these standard wireless technologies, and we specifically study the MAC and physical layer technologies proposed to address the requirements and challenges of wireless communications. Furthermore, we explain the use of these standards in various application domains, such as smart homes, smart healthcare, industrial automation, and smart cities, and discuss their suitability in satisfying the requirements of these applications. In addition to proposing guidelines to weigh the pros and cons of each standard for an application at hand, we also examine what new strategies can be exploited to overcome existing challenges and support emerging IoT applications
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