• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.411-417
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• 2008

This paper proposes BSFP (Bluetooth Scatternet Formation Protocol), which establishes a multi-hop bluetooth scatternet. BSFP independently operates on each bluetooth device, does not require any information on neighbor devices at the very beginning, and can establish a scatternet even though all the devices are spreaded beyond the bluetooth transmission range. BSFP is composed of the following three stages; 1) Init stage to investigate neighbor nodes, 2) Ready stage to establish a scatternet using gathered local information at each node, and 3) Complete stage to use the determined scatternet links. In BSFP, the scatternet formation time does not significantly affected by the number of bluetooth devices and a robust mobile ad hoc network is formed because BSFP formulates a scatternet with many adjacent links to neighbor devices.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.358-360
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• 2002

Bluetooth는 기기들간에 고정된 제어 장치를 갖지 않고 각각의 이동 기기가 스스로piconet 이라는 불리는 네트워크를 구성하게 되고, 이 piconet을 확장하여 scatternet을 구성하게된다. 이 scatternet의 형태는 Bluetooth 망 전체 성능에 큰 영향을 미치게 되는데. 본 논문에서는 지금까지 제시된 scatternet의 구성 방법들을 알아보고 scatternet을 구성하기 위해 piconet간에 공유되는 bridge 노드의 숫자를 2개까지 늘려서 원활한 통신과 안정적인 망 구성을 위한 방안을 제시한다. 또한, 성능 분석을 위하여 Bluetooth 전문 시뮬레이터인 IBM의 BlueHoc을 사용하여 bridge 노드수와 scatternet을 구성하는 piconet수의 변화에 따른scatternet의 성능을 모의 실험을 통해 측정하여 보았다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.592-594
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• 2004

Bluetooth 칩셋의 생산량을 보면, 보이지 않는 곳에서 Bluetooth의 성장은 계속 되고 있다. [1] 그리고 Bluetooth는 Scatternet을 구성하여 Personal Area Network의 영역을 넘어 Senssor network에 적용하는 것이 가능하다. 그러나 Bluetooth specification[2]에서는 Scatternet Formation 방법에 대해 제안하지 않는다. 이를 개선하기 위해 BTCP (Bleutooth Topology Construction Protocol)[3], Bluetree[4], Bluenet[5], TPSF(Two-Phase Scatternet Formation) protocol[6]이 제안되었다. 본 논문에서는 이러한 protocol들을 개략적으로 설명하고 그에 대한 장단점을 알아보겠다.

• Journal of KIISE:Information Networking
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• v.31 no.3
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• pp.314-326
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• 2004

Bluetooth has been reputed as a wireless ad-hoc networking technology supplying scalable and extensible networks between digital devices. For that kind of networks, scatternet is a most essential part in bluetooth. But past researches on bluetooth scatternet has proposed only possibilities of scatternet algorithm based on simulation results. And many of the researches failed in guaranteeing extensibility and flexibility and had many difficulties in real hardware implementation. In this paper, we proposed node ring scatternet(NRS) algorithm guaranteeing extensible and flexible networks. NRS algorithm is designed for hardware implementation using real commercial bluetooth module. That algorithm is divided into initial formation and reformation. For initial formation, we proposed limited SEEK/SCAN algorithm. For reformation, we proposed DIAC algorithm and Reserved Recovery Node algorithm. And we proposed SFMP(Scatternet Formation ＆ Management Protocol) in protocol stack for real implementation. NRS algorithm is operated in SFMP. Finally, we performed real hardware experiments and evaluated the proposed algorithm. In that experiments, we succeeded in forming scatternet up to 20 nodes. In comparison with other similar algorithm, proposed algorithm have the improvement in scatternet formation delay and success rate.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.59-69
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• 2006

Bluetooth is reputed as a wireless networking technology supplying ad-hoc networks between digital devices. In particular, Bluetooth scatternet is an essential part of dynamic ad-hoc networks. Yet, there have not been sufficient researches performed on scatternet environment. This paper proposes a scatternet reformation algorithm for ad-hoc networks for instances where some nodes enter or leave the scatternet. The proposed algorithm is a general algorithm that can be applied to many types of Bluetooth scatternet regardless of the topology. The proposed algorithm is made for two reformation cases, i.e., nodes leaving and nodes entering. For the reformation when nodes leave a scatternet, the recovery node vector (RNV) algorithm is proposed. It has short reformation setup delay because the process involves a single page process (not including inquiry process). For the reformation when nodes enter a scatternet, the entry node algorithm is proposed. This is a simple and easily implementable algorithm. In this paper, real hardware experiments are carried out to evaluate the algorithm's performance where the reformation setup delay, the reformation setup probability and the data transfer rate are measured. The proposed algorithm has shown improvement in the reformation setup delay and probability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10A
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• pp.838-846
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• 2003

In Bluetooth networks, the scatternet is defined as the internetworking of multiple piconets. Currently, Bluetooth standardization does not include the formation issue of scatternet by piconets. The existing formation algorithms of scatternet do not support the features of ad-hoc networks, which cause the performance degradation of systems when the nodes have certain degree of mobility. Therefore, as the formation of scatternet gets complicated, the throughput is lowered and the delay increases due to the inefficient architectural problems. In this paper, we propose the distributed formation scheme for bluetooth in scatternet, in which the nodes are spread out to form scatternet. Simulation results show that the proposed algorithm outperforms the conventional schemes.

• Journal of KIISE:Information Networking
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• v.32 no.1
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• pp.110-122
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• 2005

Bluetooth has been reputed as a wireless networking technology supplying ad-hoc networks between digital devices. In particular, bluetooth scatternet is a most essential part for dynamic ad-hoc networks. But past researches on bluetooth scatternet has hardly treated dynamic scatternet environment. In this paper, we proposed a scatternet reformation algorithm for the case that some nodes escape from the scatternet. The proposed algorithm is a general algorithm which can be applied to many types of bluetooth scatternet regardless of the topology. The proposed algorithm has short reformation time delay because the process has only page process (not including inquiry process ). The algorithm is operated based on Recovery Node Vector which is composed of Recovery Master and Recovery Slave. In this paper, we performed the real hardware experiments for evaluating the performance of the proposed algorithm. In that experiments, we measured the reformation time and reformation probability. In comparison with the case including inquiry process, the proposed algorithm had the improvement in reformation time delay and we obtained high success rate over 97%.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1233-1236
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• 2002

다수의 Bluetooth 장치가 사용되는 곳에서의 데이터 통신에는 scatternet의 형태가 데이터 전송 효율성에 크게 영향을 미친다. 본 논문에서는 과도한 지연시간을 초래하지 않으면서도장치 간 평균 홉 횟수를 기존 방법보다 감소시킬 수 있는 scatternet 형성 알고리즘을 제시하고 시뮬레이션을 통해 기존 알고리즘과 비교한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.9 s.339
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• pp.57-64
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• 2005

A Piconet consists of Master device and several Slave devices. Master and Slave devices are transmitted using TDD (Time Duplex Oivision) in a Piconet. A Scattemet constructed by several Piconets communicates by a Piconet. Bluetooth Specification defines the meaning of a Scatternet. But the formation and scheduling method is not defined. For the efficient formation of a Scatternet, the preceding research proposes a tree-shape topology Scatternet. But this research passes over the characteristic of Bluetooth transmission carried out by a Piconet in the Scattemet. So this Paper proposes a efficient throughput tree formation Scatternet algorithm To improve the throughput of a Scatternet, this paper proposes a tree tolopology that guarantees the efficient throughput of a Piconet

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.467-476
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• 2003

In this paper, we propose an efficient MAC scheduling algorithm for supporting Bluetooth scatternet operations. Our proposed algorithm improves overall performances of scatter mode［2, 3] and considers QoS requirements of each link of the bridge node of a scatternet. Scatter mode is based on time division scheduling and provides every links of a scatternet with fair service opportunities. However, since each Bluetooth devices has various traffic characteristics. fair allocation of service opportunities is not efficient and may cause extravagance of wireless resources. Therefore, we propose a new efficient inter-piconet scheduling algorithm compliant with the current Bluetooth specification［1］, and demonstrate its improved performances via computer simulations.