• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.792-803
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• 2005

Ultra wide band (UWB) technology will be applied in the high rare wireless personal area networks (WPANs) for its high rate, low power, and innate immunity to multipath fading. In this paper, a power aware multi-hop packet relay MAC protocol in UWB based WPANs is proposed and a power aware path status factor (PAPSF), which is derived from SINR and power resource condition of each device, is used to select a suitable relay node. Compared with relaying by piconet coordinator (PNC), which is easily chosen by other ad hoc routing protocol, the new scheme can achieve hi임or throughput, decrease the time required for transmitting high power signal and we can easily distribute the battery power consumption from PNC to other devices in the piconet to prevent the PNC device using up its battery too fast and finally avoid PNC handover too frequently.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.1-12
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• 2005

In wireless personal area networks(PANs), the successful design of channel time allocation algorithm is a key factor in guaranteeing the various quality of service(QoS) requirements for the stringent real-time constraints of multimedia services. In this paper we propose a dynamic channel time allocation algerian for providing delay guarantees to multimedia traffics such as MPEG streams in the IEEE 802.15.3 high-rate WPANs. The dynamic algorithm exploits the characteristics of MPEG stream, wherein the devices (DEVs) send their channel time requests only at the end of superframe boundaries. The algerian uses mini packets for feedback control in order to deliver dynamic parameters for channel time requests from the DEVs to the piconet coordinator (PNC). In this scheme, the duration of channel time allocated to a DEV during a superframe is changed dynamically depending on the MPEG frame type, traffic load and delay bound of the frame, etc. Performance of the proposed scheme is investigated by simulation. Our results show that compared to traditional scheme, the proposed scheme is very effective and has high performance while guaranteeing the delay bound.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.844-851
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• 2004

Various types of error are caused due to many factors of various environment in air interface channel of wireless communications. In this case, the reliability of the channel is much lower than that of wired case. IEEE 802.15.3 high-rate WPAN, which operates in an ad hoc networking environment, is more susceptible to such errors. The problem has been investigated for wireless LANs, for example, as follows. If the queue size of a certain node is longer than that of other nodes, the node estimates that its channel state is bad and the resource of the node is decreased. However this method has a disadvantage that a central controller must always monitor the status. To avoid this disadvantage, in this paper, a new MAC protocol that the throughput of overall piconet is increased by LDS (Link-status Dependent Scheduling) is proposed.

• Journal of Internet Computing and Services
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• v.9 no.1
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• pp.159-170
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• 2008

The ubiquitous network revolution is beginning with the onset of digital convergence, whereby computers, horne appliances, and communications and broadcast media are being unified into digital media with the founding of the information super high speed. This technical advancement is creating a new culture and a new space and accelerating society's transition to the new and unique social paradigm of a 'ubiquitous society'. In particular, studies on ubiquitous communications are well underway. Lately, the focus has been on the Bluetooth technology due to its applicability in various environments. Applying Bluetooth connectivity to new environments such as ubiquitous or sensor networks requires finding new ways of using it. Thus, the scalable Bluetooth piconet scheme with independent slave device is proposed. It follows from work by Sea et al. But extended scatternet is not considered is Kiisc05 paper. Therefore, we propose secure bridge connection scheme for scalable Bluetooth scatternet.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.89-97
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• 2008

In wireless personal area networks (WPANs), the successful design of channel time allocation algorithm is a key factor in guaranteeing the various quality of service (QoS) requirements for the stringent real-time constraints of multimedia services. In this paper we propose a channel time allocation algorithm for achieving a high quality transmission and high channel error tolerance of MPEG stream in the IEEE 802.15.3 high-rate wireless PANs. Our algorithm exploits the characteristics of MPEG stream. When a new MPEG stream arrives, a DEV models it by the traffic envelope and delivers the traffic envelope to the piconet coordinator (PNC) along with the channel time request. The PNC performs channel time allocation according to the envelope. Performance of the proposed scheme is investigated by simulation and analysis. Our results show that compared to conventional scheme, the proposed scheme is very effective and provides a good performance under typical channel error conditions.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.3
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• pp.208-212
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• 2008

This paper proposes a model of a voice communication using bluetooth and a mobile, and implements a hands-free for this model. A Proposed model uses bluetooth for a voice network, and is possible to share a voice with a great number of people using preemptive algorithm proposed in this paper. There are two types of models. One is a model only using a hands-free, the other is a model using a mobile. Second model uses a scatternet and a call forwarding service for a call on a voice communication. In case of using a scatternet, scatternet is composed of a piconet of a voice communication and a piconet of a call. In case of using a call forwarding service, the mobiles share information of each others before formation of a network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.45-48
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• 2004

RFID(Radio Frequency Identification) which is emerging from a change in digital convergence paradigm and recently rapidly advancing throughout the overall society is the core technology based on Ubiquitous network. In other words, This is a technology to identify the information of the object and recognize the situation by attaching electrical tag to an object and using Reader that can read the information of the object. With the emergence of the technology, it has turned the existing maintenance of the product into the network and intelligence of the product control by using the bar cord to maintain the product and will lead a revolution throughout overall society by affecting the fields of distribution and product maintenance as well as those of medicines, chemicals and food which the electrical tag can be attached to. this paper shows that utilizing the Bluetooth which is a local wireless telecommunication in the standalone imbedded system can implement the piconet configuration among the Readers and the data telecommunication with the main server

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.187-189
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• 2002

본 논문에서는 효율적인 인터 피코넷 스케줄링 방식과 현재까지 연구된 인트라 피코넷 스케줄링을 인터 퍼코넷 스케줄링으로 적용할 때의 성능을 분석한다. 스캐터넷에서 피코넷 간의 통신이 가능한 블루투스 시뮬레이터를 구현하여 실험하며, 이때 평균 패킷의 전송 지연 시간을 측정하여 각 인터 피코넷 스케줄링의 성능을 분석한다. 비교 분석을 위해 PRR, ERR, LWRR 스케줄링 방범을 블루투스 시뮬레이터에 구현만다. 인트라 피코넷 스케줄링을 PRR, ERR, LWPR 방식으로 동작시킬 때 각각 인터 피코넷 스케줄링으로 PRR, ERR, LWRR을 적용한다. 실험결과는 스니프 모드 사용방식의 PRR을 인터 피코넷 스케줄링으로 적용 할 때 인트라 피코넷 스케줄링에 독립적으로 제일 낮은 평균 패킷 전송지연 시간을 가짐을 보인다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.2
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• pp.201-207
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• 2003

A multi-hop ad-hoc network can be formed out of Bluetooth capable devices through the use of scatternets. Many topologies can be deployed for scatternet; the most commonly proposed topology in the literature are tree structure and ring structure. We analyze the performance between tree formation algorithm and ring formation algorithm. We then present quantative result that compare the expected traffic performance between Blutooth ring scatternet and Bluetooth tree scatternet. The simulation results showes that Ring structure of scatterent have good performance than Tree structure over mobile environments.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.196-198
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• 2002

오늘날 무선통신 기술은 기존 유선 통신방식에 추가하여 매우 주목받고 있는 정보통신 혁명을 주도하였다. 무선 통신에서 자체 피코넷(piconet)을 형성하여 음성이나 데이터 통신을 수행하는 이러한 블루투스 기술은 많은 응용분야에 적용되고 있고 이제 액세스 망을 통해 공중망과 접속 가능하게 되었다. 본 논문에서는 이러한 블루투스 프로토콜의 핵심적인 기술을 교육하기 위하여 블루투스 디바이스와 RS232 또는 USB 인터페이스로 접속된 PC에서 블루투스 프로토콜의 핵심적인 스택인 HCI, L2CAP, RFCOMM, SDP를 설계, 구현하였다. 아울러 PC 상에서 이러한 블루투스 프로토콜을 체계적이고 쉽게 교육하고자 교육용 소프트웨어를 개발하였다. 이의 개발 환경으로는 윈도우 OS와 비주얼 C++을 사용하였다. 비주얼 C++로 작성된 프로그램은 블루투스 디바이스에 실장 된 펌웨어와 인터페이스를 수행하여 개발되었다.