Bluetooth Scatternet Research Articles

Relay Based Performance Metrics of Bluetooth Scatternet Scheduling

<p>Bluetooth is an emerging mobile ad-hoc network that accredits wireless communication to connect various short range devices. A single hop network called piconet is the basic communication topology of bluetooth which allows only eight active devices for communication among them seven are active slaves controlled by one master. Multiple piconets are interconnected through a common node, known as Relay, to form a massive network called as Scatternet. It is obvious that the performance of Scatternet scheduling is highly dependent and directly proportionate with the performance of the Relay node. In contrary, by reducing the number of Relays, it may lead to poor performance, since every Relay has to perform and support several piconet connections. The primary focus of this study is to observe the performance metrics that affects the inter-piconet scheduling since the Relay node’s role is like switch between multiple piconets. In this paper, we address and analyze the performance issues to be taken into consideration for efficient data flow in Scatternet based on Relay node.</p>

Reliable Formation Protocol for Bluetooth Hybrid Single-hop and Multi-hop Networks

There are presently many applications where a non-uniform distribution of devices needs to be established for Bluetooth scatternets. Under the scenario of one dense zone and multiple sparse zones, the dense area has a high probability of generating a single-hop scenario since most devices are within radio range, whereas most devices are out of radio range under the multi-hop scenario in other sparse areas. Thus, both situations have to be considered in the formation of an algorithm design for most real-life situations. This work proposes a reliable formation protocol, called Dual-Ring Tree, for hybrid single-hop/ multi-hop instances. To benefit from the advantages of the hybrid scenarios, a dual-ring subnet is presented as a single-hop solution for dense areas, while a tree-shaped subnet is designed as a multi-hop solution for sparse areas. To the best of the authors' knowledge, this is the first time such an algorithm has been designed to deal with both single-hop and multi-hop scenarios. The computer simulation results suggest that the reliable Dual- Ring Tree outperforms conventional BlueHRT in terms of routing efficiency and network reliability for Bluetooth multi-hop networks.

GreenLink: An Energy Efficient Scatternet Formation for BLE Devices

Formation technology of Bluetooth scatternet has been researched for over a decade and promoted by rapid development of wearable computing. Limited by technical features, the traditional scatternet formation technology has not been widely used in real commercial chipsets. As new features are introduced into the Bluetooth core field, the ability to use Bluetooth Low Energy (BLE) technology to construct a network becomes the reality and puts forward new challenges. The scatternet formation technology facing to BLE and wearable devices requires significant improvement in energy efficiency. According to our experiments, 92% of the system energy consumption can be attributed to central nodes. In this paper, we presented a Bluetooth scatternet formation technology focused on energy efficiency, GreenLink, which minimizes the amount of central nodes by enhancing system aggregation degree to ensure excellent energy‐saving performance. Meanwhile, we implemented a prototype of GreenLink on Nordic nRF51822 chipsets, conducted experiments, and verified in practice. According to the experiments, GreenLink used only 30% central nodes and reduced 50% system energy consumption compared with traditional technology.

A Review of Bluetooth based Scatternet for Mobile Ad hoc Networks

Bluetooth based networking is an emerging and promising technology that takes small area networking to an enhanced and better level of communication. Bluetooth specification supports piconet formation. However, scatternet formation remains open. The primary challenge faced for scatternet formation is the interconnection of piconets. This paper presents a review of the proposed approaches and the problems confronted for establishing scatternet for ad hoc networks specifically MANET. In this work, a comparison of the Blue layer algorithm with MMPI interface based algorithm on Bluetooth scatternet formation. The enhancement in the developed MMPI framework makes it a good option for scatternet applications.

Resource Optimization Routing and Scatternet Formation Protocols for Bluetooth Networks

Limited resources and network dynamicity are challenging issues in Bluetooth networks. Therefore, scatternet formation improvement and efficient routing algorithms are required that can efficiently construct a short route between a source and destination. As of today, many protocols have been proposed, mostly researchers focusing on simplicity and reliability, but only few of them fulfill the Bluetooth scatternet scenario. Therefore, it opens new doors for scatternet formation and inter-piconet routing for the Bluetooth scatternet. This paper presents a review of Bluetooth routing and scatternet formation protocols for inter-piconet communication. First, Bluetooth operation is explained followed by important applications and topologies are discussed. Then, inter-piconet routing and network formation protocols are critically analyzed. Finally, Bluetooth problems and open research issues are highlighted.

A Self-organizing Location and Mobility-Aware Route Optimization Protocol for Bluetooth Wireless

Bluetooth allows multi-hop ad-hoc networks that contain multiple interconnected piconets in a common area to form a scatternet. Routing is one of the technical issues in a scatternet because nodes can arrive and leave at arbitrary times; hence node mobility has a serious impact on network performance. Bluetooth network is built in an ad-hoc fashion, therefore, a fully connected network does not guarantee. Moreover, a partially connected network may not find the shortest route between source and destination. In this paper, a new Self-organizing Location and Mobility-aware Route Optimization (LMRO) protocol is proposed for Bluetooth scatternet, which is based on node mobility and location. The proposed protocol considered the shortest route ahead of the source and destination nodes through nodes location information. In addition, proposed protocol guarantees network connectivity through executing Self-organizing procedure for the damaged route by considering signal strength. The proposed LMRO protocol predicts node mobility through the signal strength and activates an alternate link before the main link breaks. Simulation results show that the LMRO protocol has reduced the average hop count by 20%-50% and increased network throughput by 30%-40% compared to existing protocols

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.

Reconfigurable Algorithm for Bluetooth Sensor Networks

In this letter, a reconfigurable formation algorithm is proposed for Bluetooth scatternets. First, a root node propagates parameters <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</i> in the downstream direction to construct a tree-shaped subnet and determines new roots. Each new root then sends a request to its upstream master to initiate a return connection in order to convert the first tree-shaped subnet into a mesh-shaped subnet. In addition, a peak-search method was introduced in the first root node to locate the optimum <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> layer and generate an optimum mesh-tree topology. Simulation results show that the peak-search method outperforms conventional blueHRT in the context of Bluetooth-based sensor networks.

An Enhanced Protocol for Bluetooth Scatternet Formation and Routing

Formation of scatternet using Bluetooth devices increases device tractability thereby inviting new networking applications to be designed on it. In this paper we propose Bluetooth Scatternet Formation and Routing Protocol (BSFRP). It is a distributed protocol that handles node mobility and enables multi-hop communication. BSFRP defines rules for topology discovery, scatternet formation and routing. The scatternet phase of the protocol works on the principle of leader election. For routing, AODV is modified to address the constraints of scatternets. It improves the AODV route discovery phase by considering hop count, residual node's power, and route lifetime for best route selection. Simulation results show that the scatternet formed by BSFRP has the following properties: the number of piconets formed is close to the universal lower bound, each device on an average does not assume more than 1.15 roles, and the scatternet does not contain any master-slave bridge.

Note: Methodology for the analysis of Bluetooth gateways in an implemented scatternet

This Note introduces a novel methodology to analyze the time performance of Bluetooth gateways in multi-hop networks, known as scatternets. The methodology is focused on distinguishing between the processing time and the time that each communication between nodes takes along an implemented scatternet. This technique is not only valid for Bluetooth networks but also for other wireless networks that offer access to their middleware in order to include beacons in the operation of the nodes. We show in this Note the results of the tests carried out on a Bluetooth scatternet in order to highlight the reliability and effectiveness of the methodology. The results also validate this technique showing convergence in the results when subtracting the time for the beacons from the delay measurements.

Bluetooth scatternet formation from a time-efficiency perspective

The Bluetooth Scatternet Formation (BSF) problem consists of interconnecting piconets in order to form a multi-hop topology. While a large number of BSF algorithms have been proposed, only few address time as a key parameter, and when doing so, virtually none of the solutions were tested under realistic settings. In particular, the baseband and link layers of Bluetooth are highly specific and known to have crucial impacts on performance. In this paper, we revisit performance studies for a number of time-efficient BSF algorithms, focusing on BlueStars, BlueMesh, and BlueMIS. We also introduce a novel time-efficient BSF algorithm called BSF-UED (for BSF based on Unnecessary-Edges Deletion), which forms connected scatternets deterministically and limits the outdegree of nodes to 7 heuristically. The performance of the algorithm is evaluated through detailed simulation experiments that take into account the low-level specificities of Bluetooth. We show that BSF-UED compares favorably against BlueMesh while requiring only 1/3 of its execution time. Only BlueStars is faster than BSF-UED, but at the cost of a very large number of slaves per master (much more than 7), which makes it impractical in many scenarios.

Internet Scheduling of Bluetooth Scatter Nets By Inter Piconet Scheduling

Internet Scheduling of Bluetooth Scatter Nets By Inter Piconet Scheduling

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 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.

Internet Scheduling of Bluetooth Scatter Nets by Inter Piconet Scheduling

Internet Scheduling of Bluetooth Scatter Nets by Inter Piconet Scheduling

Link Repairing for Inter-Piconet CommunicationTechnique in Bluetooth Scatternet

Link Repairing for Inter-Piconet CommunicationTechnique in Bluetooth Scatternet

A Bluetooth Scatternet Route Optimization Protocol

Bluetooth wireless network technology is an emerging technology that allows Bluetooth devices to form a multi-hop ad hoc network known as a scatternet. Efficient routing in a scatternet has positive impacts on the performance of a network but the routing for inter-piconet communication has not been standardized yet. Many protocols have been proposed for route optimization but they still need more development. In a previous work, the route request packet was flooded throughout the network in order to find the main route. In this paper a Bluetooth Scatternet Route Optimization Protocol (SROP) is proposed. The SROP gets the information of all the possible paths through flooding. It floods the route request packets to the bridge and master devices and then chooses the appropriate path. After selecting the path, it then performs network restructuring to reduce the number of hop counts between the source and the destination. Simulation results reveal that the proposed protocol has achieved enhancement over the enhanced AODV protocol by increasing the ratio of the data packet delivery, reducing the delay time, minimizing the number of hop counts between the source and the destination. Consequently, it improves the whole network throughput.

Dynamic relay management protocol for efficient inter-piconet scheduling in Bluetooth scatternet

Bluetooth is a low power, short range and inexpensive wireless technology that has limited resources. Therefore, the performance of a scatternet is highly dependent on the number of relays and their degree. The existence of unnecessary relays may increase scheduling overhead and consume system resources. In another instance, a large number of links that pass through a single relay may also decrease the system performance. Therefore, an optimum number of relays must be obtained for an efficient scatternet performance, while the system works with limited resources. The dynamic relay management (DRM) protocol is proposed to achieve the said objective and the solutions will be based on relay reduction and load balancing strategies. Through the DRM, a master reduces unnecessary relays to an optimum number and subsequently assigns them the special role as backup relays. In the event when a large number of links pass through a single relay, the master activates one of the backup relays to resolve the bottleneck, by which the load is balanced over a number of relays. Using this relay management technique, analytically the DRM protocol has reduced control overhead from O(n2) to O(1). Empirically, through simulation of the DRM protocol, the backup relay activation has reduced delay and improved throughput (between 40% and 60%). Also, the simulation results have demonstrated an improvement on network lifetime and packet loss. All these results are evidence that the DRM has outperformed the RVM and LORP protocols for the same issue. Hence, the inefficiency of the inter-piconet scheduling in a scatternet of a Bluetooth network can be resolved by implementing the DRM protocol.

Dynamic Congestion Control through backup relay in Bluetooth scatternet

Bluetooth is a low power wireless technology designed to connect various short-range devices such as laptops, cameras, cell-phones, head-phones, navigators, etc. Bluetooth has limited resources and its devices are connected in ad hoc fashion. The Bluetooth specification allows only eight active devices to communicate within its smallest networking unit known as piconet. Multiple piconets can be connected together through at least one common device, known as relay to form a bigger network called a scatternet. The performance of a scatternet is highly determined by the performance of the relay since it acts as a switch between multiple piconets, where inter-piconet scheduling is the main task to perform. However, the presence of too many relays in the network may cause inefficient use of the limited resources. In contrary, less number of relays may lead to congestion problem because each relay has to participate in multiple piconets and supports several connections. One possible solution is to reorganize the nodes in the scatternet, in order to increase the available bandwidth and to reduce the traffic flows on the congested link. Hence, primarily this paper addresses the issues of traffic congestion on a link by analyzing traffic load in the network. To achieve this, activation of a backup relay is performed by applying role-switching operation, and this technique is called Dynamic Congestion Control (DCC). With DCC, the route length is assured not to increase as to alleviate message and packet overheads in scheduling. The simulation results are evidence that DCC has reduced transmission delays and has increased the scatternet lifetime from 25% to 50% as compared to RVM and LORP techniques.