Scatternet Formation Algorithm Research Articles

Forming MS-Free and Outdegree-Limited Bluetooth Scatternets in Pessimistic Environments

This paper introduces two distributed Bluetooth scatternet formation (BSF) algorithms, called $\mathtt{BSFWAVVY(MSF)}$ and $\mathtt{BSFWAVVY(ODL)}$ . The first algorithm forms scatternets that does not contain master–slave (MS) bridges (MS-free scatternets), whereas the second algorithm forms scatternets in which each piconet has at most $k$ slaves (outdegree-limited scatternets). The motivation is that MS-freeness and outdegree limitation are the two properties that significantly improve the quality of the scatternets. However, and contrary to the existing BSF algorithms, our algorithms consider these properties under pessimistic environments modeled as arbitrary networks (i.e., no assumptions are made on the underlying network topology). We give two lower bounds that prove the asymptotic optimality of our algorithms with respect to time complexity and message complexity. We also show that the problem of forming MS-free and outdegree-limited scatternets at the same time is ${\sf{NP}}$ - ${\sf{COMPLETE}}$ . We introduce a time-efficient implementation of $\mathtt{BSFWAVVY(MSF)}$ and $\mathtt{BSFWAVVY(ODL)}$ that exploits unique characteristics of Bluetooth networks. Simulation experiments show that our algorithms have short execution time relative to major BSF algorithms and it outperforms other major algorithms with respect to various performance metrics.

A Source Routing Protocol for Bluetooth-Based Sensor Networks

Blueweb is a self-organizing Bluetooth-based multihop network equipped with a scatternet formation algorithm and a hybrid routing protocol. The routing protocol combines the reactive method globally and the proactive method locally to discover the optimal path for packet transmission. In Blueweb, the route master maintains the global topology information and each master maintains its own N-tier routing information. In this paper, a tier number decision algorithm is used in Blueweb to determine the optimal number of tiers for all the other masters. Our computer simulation results show that this algorithm can efficiently improve the routing performance and reduce the routing maintenance cost for Blueweb routing protocol.

Enhanced Bluetree: a mesh topology approach forming Bluetooth scatternet

This study presents the enhanced Bluetree, a mesh topology scheme for Bluetooth scatternet formation. The scatternet formation algorithm includes two phases. In the first phase, a root node begins to create a conventional tree-shaped topology. To improve the network reliability of tree topology, a return connection mechanism is introduced in the second phase to generate more connection paths and to convert the tree-shape into a mesh-shaped topology. The mechanism contains two connection models including the ‘slave/slave mesh’ (SSM) and the ‘master/slave mesh’ (MSM) models. The SSM model builds a mesh-shaped topology by interconnecting more leaf nodes, whereas the MSM model connects additional intermediate nodes to establish the backbone connection in a mesh-shaped topology. Simulation results show that the enhanced Bluetree effectively improves the performance metrics, including the piconet efficiency, path length and end-to-end delay, beyond the Bluetree with more formation packets. As a result, the enhanced Bluetree not only builds a mesh-shaped topology that improves the network reliability but also generates an efficient network with less packet delay performance than a conventional Bluetree network.

Towards better understanding of the behaviour of Bluetooth networks distributed algorithms

The use of frequency hopping spread spectrum in Bluetooth significantly differentiates its networks from classical radio networks. In order to observe such differences, we studied basic algorithms, in particular neighbour discovery and message exchange algorithms. Some of the major differences are found in the procedures of device discovery and link establishment, which are studied in this paper. We focus on their impact on Bluetooth networks' distributed algorithms. We show through detailed simulation experiments that minor modifications to the Bluetooth specifications or their implementation may significantly affect the performance of well-known neighbour discovery algorithms. We then study the impact of the procedures of link establishment with the purpose of finding time-efficient implementations of communication rounds for Bluetooth networks. We study OrderedExchange and RandomExchange as both algorithms implement communication rounds in Bluetooth, but use the PAGE and PAGE SCAN states differently. Theoretical analysis shows that RandomExchange has a better time complexity, while simulation experiments show that OrderedExchange significantly outperforms RandomExchange in networks with a practical size (110 nodes and less). We use the previous results to improve the time efficiency of Bluetooth scatternet formation algorithms through the introduction of the time-efficient algorithm OrderedExchangeCMIS. We believe that the study of some other basic algorithms (such as broadcasting, spanningtree and election) will lead to a better understanding of Bluetooth networks, and as a consequence, to more efficient algorithms that fully leverage the strength of this type of network.

A Configurable Routing Protocol for Bluetooth Wireless Networks

Blueweb is a self-organizing Bluetooth-based multihop network equipped with a scatternet formation algorithm and a hybrid routing protocol. The routing protocol combines the reactive method globally and the proactive method locally to discover the optimal path for packet transmission. In Blueweb, the route master maintains the global topology information and each master maintains its own N-tier routing information. In this paper, a tier number decision algorithm is used in Blueweb to determine the optimal number of tiers for all the other masters. Our computer simulation results show that this algorithm can efficiently improve the routing performance and reduce the routing maintenance cost for Blueweb routing protocol.

A Mesh Topology Approach for Bluetooth Scatternet Formation

This paper presents the Enhanced Bluetree, a mesh topology scheme for Bluetooth scatternet formation. The scatternet formation algorithm includes two phases. In the first phase, a designated node called the root starts to create a tree-shaped topology and in the second phase the tree-shaped topology is converted into a mesh-shaped topology. In addition, a return connection mechanism is introduced in this phase to generate more connection paths among the nodes. The mechanism contains two scatternet topology models including the slave/slave mesh (SSM) model and the master/slave mesh (MSM) model. The SSM Model builds a mesh-shaped topology by interconnecting more leaf nodes. On the other hand, the MSM Model connects additional intermediate nodes to establish the backbone connection in a mesh-shaped topology. Simulation results show that both the SSM and the MSM of an Enhanced Bluetree more effectively improve the network performance than Bluetree by significantly reducing the average path length.

Global configured method for Blueweb routing protocol

Blueweb is a self-organising Bluetooth-based multihop network equipped with a scatternet formation algorithm and a hybrid routing protocol. The hybrid routing protocol combines the reactive method globally and the proactive method locally to discover the optimal path for packet transmission. This protocol can be configured for a particular network through adjustment of a single parameter, the number of routing tier. A global configured method is proposed by the authors to determine the desired configuration for Blueweb routing protocol. The global configured method is used in the route master and designs three blocks, including the traffic generator, the query packet estimator and the global tier decision blocks. The traffic generator block uses a uniform end-to-end traffic model in each master to generate the query packets for various N-tiers. The query packet estimator block measures the local and global query packets to compute the local query probability. The global tier decision block uses the parameter of local query probability to determine the proper number of routing tier. Computer simulation results show that this method can efficiently improve the routing performance and make the routing tiers configurable for a Blueweb routing protocol.

A scatternet formation algorithm for Bluetooth networks with a non-uniform distribution of devices

We address the problem of scatternet formation for network scenarios with a non-uniform distribution of Bluetooth devices. The assumption of having a non-uniform distribution of devices in a given area of interest is motivated by examples that can be encountered in real scenarios. We propose a new scatternet formation protocol called BlueHRT (Bluetooth Hybrid Ring Tree) that results in a hybrid ring tree topology. The proposed protocol operates in multiple phases that include node discovery, identification of a dense area within the network, role assignment with ring based piconets in the dense area and tree based piconets in the surrounding lightly loaded areas, and interconnection of the piconets to each other via slave–slave and master–slave bridges. General protocol design analysis and ns-2 simulation results are presented in order to highlight the main performance characteristics.

HMT: A Hybrid Mesh Tree Algorithm in Forming Bluetooth Networks

In this letter, a new scatternet formation algorithm called hybrid mesh tree for Bluetooth ad hoc networks was proposed. The hybrid mesh tree constructs a mesh-shaped topology in one dense area that is extended by tree-shaped topology to the other areas. First, the hybrid mesh tree uses a designated root to construct a tree-shaped subnet, and then propagates a constant k in its downstream direction to determine new roots. Each new root then asks its upstream master to start a return connection procedure to convert the first tree-shaped subnet into a mesh-shaped subnet. At the same time, each new root repeats the same procedure as the designated root to build its own tree-shaped subnet until the whole scatternet is formed. Simulation results showed that the hybrid mesh tree achieved better network performance than Bluetree and generated an efficient scatternet configuration for various sizes of Bluetooth scatternets.

Black Bridge: Scatternet Formation Algorithm for Solving a New Emerging Problem

Nowadays, it has become common to equip a device with Bluetooth. As such devices become pervasive in the world; much work has been done on forming them into a network, however, almost all the Bluetooth Scatternet Formation Algorithms assume devices are homogeneous. Even the exceptional algorithms barely mentioned a little about the different characteristics of devices like computational abilities, traffic loads for special nodes like bridge nodes or super nodes, which are usually the bottleneck in the scatternet. In this paper, we treat the devices differently not only based on the hardware characteristics, but also considering other conditions like different classes, different groups and so on. We use a two-phase Scatternet Formation Algorithm here: in the first phase, construct scatternets for a specified kind of devices; in the second phase, connect these scatternets by using least other kinds of devices as bridge nodes. Finally, we give some applications to show the benefit of classification.

Multi-hop scatternet formation and routing for large scale Bluetooth networks

This paper addresses the scatternet formation for large scale multi-hop Bluetooth networks. We first describe an efficient method to build a Connected Dominating Set (CDS) as the backbone of multi-hop Bluetooth network, then propose new algorithms to form the dBBlue scatternets (Song et al., 2005) in each cluster. The final scatternet, M-dBBlue, guarantees the connectivity. Our experiment shows our scatternet seldom parks any node. We then propose a complete set of hierarchical routing methods for M-dBBlue which enables the self-routing inside each cluster. Moreover, our scatternet formation and routing algorithm do not necessarily require position information of the node.

Introduction to Blueweb: A Decentralized Scatternet Formation Algorithm for Bluetooth Ad Hoc Networks

In this letter, a decentralized scatternet formation algorithm called Bluelayer is proposed. First, Bluelayer uses a designated root to construct a tree-shaped subnet and propagates an integer variable k1 called counter limit as well as a constant k in its downstream direction to determine new roots. Then each new root asks its upstream master to start a return connection procedure to convert the tree-shaped subnet into a web-shaped subnet for its immediate upstream root. At the same time, each new root repeats the same procedure as the root to build its own subnet until the whole scatternet is formed. Simulation results show that Bluelayer achieves good network scalability and generates an efficient scatternet configuration for various sizes of Bluetooth ad hoc network.

Scatternet Formation Algorithm based on Relative Neighborhood Graph

This paper proposes a scatternet topology formation, self-healing, and self-routing path optimization algorithm based on Relative Neighborhood Graph. The performance of the algorithm using ns-2 and extensible Bluetooth simulator called blueware shows that even though RNG-FHR does not have superior performance, it is simpler and easier to implement in deploying the Ad-Hoc network in the distributed dynamic environments due to the exchange of fewer messages and the only dependency on local information. We realize that our proposed algorithm is more practicable in a reasonable size network than in a large scale.

Distributed Construction and Maintenance of Bandwidth and Energy Efficient Bluetooth Scatternets

Bluetooth networks can be constructed as piconets or scatternets depending on the number of nodes in the network, Although piconet construction is a well-defined process specified in Bluetooth standards, scatternet formation policies and algorithms are not well specified. Among many solution proposals for this problem, only a few of them focus on efficient usage of bandwidth in the resulting scatternets. In this paper, we propose a distributed algorithm for the scatternet formation problem that dynamically constructs and maintains a scatternet based on estimated traffic flow rates between nodes. The algorithm is adaptive to changes and maintains a constructed scatternet for bandwidth-efficiency when nodes come and go or when traffic flow rates change. Based on simulations, the paper also presents the improvements in bandwidth-efficiency and reduction in energy consumption provided by the proposed algorithm

On the Architecture and Performance of Blueweb: A Bluetooth-Based Multihop Ad Hoc Network

In this paper, we present Blueweb, a new Bluetooth-based multihop network with an efficient scatternet formation algorithm and a hybrid routing protocol. The Blueweb is designed from the original idea of Bluetree. Blueweb's scatternet formation uses two mechanisms. One is the role exchange mechanism in which only slave nodes serve as the role of relay through the whole scatternet. The other one is the return connection mechanism in which we convert the scatternet from a tree-shaped to a web-shaped topology. Meanwhile, a modified source routing protocol is designed for Blueweb in which we combine the proactive method with the reactive method to discover the optimal path for packet transmission. Furthermore, using computer simulations we compared the system performance of Blueweb and Bluetree with both a static model and a uniform traffic model. With the static model we evaluate the scatternet performance and with the uniform traffic model we evaluate the transmission performance. Our simulation results show that Blueweb achieves superior system performance than Bluetree on both scatternet performance and transmission performance.

Bluegon: a polygon‐shaped scatternet formation algorithm for Bluetooth

AbstractBluetooth is one of the cable‐replacement technologies. It uses short‐range radio links to replace connecting cables. Bluetooth enables portable devices to form short‐range wireless ad hoc networks. A set of Bluetooth devices sharing a common channel can form a personal area network called a piconet. Several piconets can also be interconnected to establish a scatternet. Zaruba, Basaghi and Chlamtac proposed a mechanism for forming a distributed scatternet called the Bluetree. The algorithm is based on selecting an arbitrary node serving as the Blueroot. The Blueroot initiates the construction of the Bluetree. Though the algorithm is very simple, there are some weak points. For example, being a tree limits its routing choices. There are also the problems of overloading on the Blueroot and the many master/slave bridges on any routing path. In this paper, we will improve the weaknesses of Bluetree by eliminating the bottleneck in the Blueroot and by reducing the number of bridges to half for almost any path. We call the new algorithm Bluegon since polygons (cycles) will be formed in the scatternet. Simulation results indicate the efficiencies of our algorithm. Copyright © 2006 John Wiley & Sons, Ltd.

A framework for building Bluetooth scatternets: A system design approach

Building Bluetooth scatternets is the focus of a lot of research activity where scatternet formation algorithms are developed to optimize various performance criteria. In this paper, we focus on establishing a framework within which these algorithms can be exploited in an operational Bluetooth network. First we review pertinent parts of the Bluetooth protocol stack and then we present issues of concern related to the direct implementation of these algorithms on Bluetooth networks. Finally, to address this issue, we introduce a framework for creating scatternets and show how existing scatternet formation algorithms can be re-used by altering the layer at which they become visible to the Bluetooth protocol stack.

Impact of topology on Bluetooth Scatternet

To utilize Bluetooth as a layer 2 multi‐hop subnet for global IP network, there are two missing protocols in current Bluetooth stack: network formation and routing. In this paper, we propose our network formation and routing protocols optimized for such Bluetooth subnset usage scenarios to fill this gap. In this paper, we first present some observations on performance degradations of Bluetooth PAN due to network topologies and topology change when radio independant protocols are implemented. And then we analyze the reason of performance degradation. Based on our analysis, we first propose a flexible scatternet formation algorithm under conference scenario for multi‐hop communication. By using proposed method, scatternet can be formed flexibly with star, mesh, or linked line based on several parameters like number of maximum piconets that a gateway Bluetooth device can participate, and whether loops are needed in the resulting scatternet to achieve better network performance. To utilize topology information in multi‐hop communication, we propose a Cross‐layer Optimized Routing for Bluetooth (CORB) CORB is a QoS‐extended AODV routing protocol with mainly two optimizations between networking layer and underlying Bluetooth MAC layer. The first optimization is to use a new load metric. (LM) in QoS routing protocol instead of number of hops in conventional best effort routing. LM is derived from estimation of nodes’ link bandwidth, which reflects the different roles of nodes in Bluetooth scatternet. This proposal helps routing protocol to bypass heavily loaded nodes, and find route with larger bandwidth. The second optimization is to adjust LM and some MAC layer parameters in response to the unstable network topology caused by movement and change of indoor radio condition. Finally, We present some simulation and experiment results based on implementation, which prove the effectiveness of our protocols.

SF-DeviL: an algorithm for energy-efficient Bluetooth scatternet formation and maintenance

Bluetooth is a short-range ad hoc networking technology, which enables formation of inexpensive personal area networks with low power consumption. Using Bluetooth technology, a small number of closely located devices can be interconnected within a piconet. Building larger ad hoc networks is possible by interconnecting multiple piconets to form a scatternet. As the Bluetooth topology grows from isolated piconets to a scatternet, energy-efficiency becomes a critical issue since additional power is consumed for multi-hop routing. A scatternet should be formed in such a way that batteries of mobile devices are efficiently used in order to lengthen scatternet lifetime. We discuss the problem of energy-efficient topology construction and maintenance for Bluetooth scatternets. An energy-efficient, distributed Bluetooth Scatternet Formation algorithm based on Device and Link characteristics (SF-DeviL) is presented. SF-DeviL forms scatternets with tree topologies and increases battery lifetimes of devices by using device types, battery levels and received signal strengths. The topology is dynamically reconfigured in SF-DeviL so that energy efficiency is maintained during the lifetime of the scatternet. It is shown through simulations that even without performing reconfiguration the network lifetime is increased by at least 229% compared to LMS algorithm and increased by at least 10% compared to BlueMesh algorithm in heterogeneous networks.

Distributed Self-Healing and Variable Topology Optimization Algorithms for QoS Provisioning in Scatternets

Bluetooth is an enabling technology for Personal Area Networks. A scatternet is an ad hoc network created by interconnecting several Bluetooth piconets, each with at most eight devices. Each piconet uses a different radio channel constituted by a frequency hopping code. The way the devices are grouped in different piconets and the way the piconets are interconnected greatly affect the performance of the scatternet in terms of capacity, data transfer delay, and energy consumption. There is a need to develop distributed scatternet formation algorithms, which guarantee full connectivity of the devices, reconfigure the network due to mobility and failure of devices, and interconnect them such a way to create an optimal topology to achieve gainful performance. The contribution of this paper is to provide an integrated approach for scatternet formation and quality-of-service support (called SHAPER-OPT). To this aim, two main procedures are proposed. First, a new scatternet formation algorithm called self-healing algorithm producing multihop Bluetooth scatternets (SHAPER) is developed which forms tree-shaped scatternets. A procedure that produces a meshed topology applying a distributed scatternet optimization algorithm (DSOA) on the network built by SHAPER is then defined. Performance evaluation of the proposed algorithms, and of the accordingly created scatternets, is carried out by using ns2 simulation. Devices are shown to be able to join or leave the scatternet at any time, without compromising the long term connectivity. Delay for network setup and reconfiguration in dynamic environments is shown to be within acceptable bounds. DSOA is also shown to be easy to implement and to improve the overall network performance.