• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.4
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• pp.379-384
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• 2002

This paper represents the mobile robot system remote controlled by PDA(personal digital assistance). So far, owing to the development of internet technologies, lots of remote control methods through internet have been proposed. To control a mobile robot through internet and guide it under unknown environment, We propose a control method activated by PDA. In a proposed system, PDA acts as a user interface to communicate with notebook as a controller of the mobile robot system using TCP/IP protocol, and the notebook controls the mobile robot system. The information about the direction and velocity of the mobile robot feedbacks to the PDA and the PDA send new control method produced from the fuzzy inference engine.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.121-124
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• 2005

The High Rate Wireless Personal Area Networks (WPAN) is mainly targeted to consumer electronics and portable communication devices which need high rates and QoS. To achieve these goals, the WPAN provides data rates up to 1Gbps and adopts a Time Division Multiple Access (TDMA) MAC protocol. Since IEEE 802.15.3 MAC is based on TDMA scheme, it has good performance in dealing with real traffics. But it does not give better results for dynamic traffic. For dynamic traffic, IEEE 802.15.3 MAC needs a kind of request and response policy that brings about the degradation of performance in order to adapt to network changes. To overcome this problem and enhance the data throughput, this paper proposes a superframe structure which uses the Enhanced Contention Access Period (ECAP) to transmit data during sleep-CTA in PM mode.

• ETRI Journal
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• v.36 no.3
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• pp.385-395
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• 2014

In this paper, we consider a resource allocation scheme for millimeter wave-based wireless personal area networks using directional antennas. This scheme involves scheduling the reservation period of medium access control for IEEE 802.15.3c. Objective functions are considered to minimize the average delay and maximize throughput; and two scheduling algorithms-namely, MInMax concurrent transmission and MAxMin concurrent transmission-are proposed to provide a suboptimal solution to each objective function. These are based on an exclusive region and two decision rules that determine the length of reservation times and the transmission order of groups. Each group consists of flows that are concurrently transmittable via spatial reuse. The algorithms appropriately apply two decision rules according to their objectives. A real video trace is used for the numerical results, which show that the proposed algorithms satisfy their objectives. They outperform other schemes on a range of measures, showing the effect of using a directional antenna. The proposed scheme efficiently supports variable bit rate traffic during the reservation period, reducing resource waste.

• ETRI Journal
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• v.34 no.1
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• pp.24-34
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• 2012

In this paper, the directional carrier sense multiple access/collision avoidance (CSMA/CA) protocol in the immediate acknowledgement mode for IEEE 802.15.3c is analyzed under saturation environments. For the analysis, a sensing region and an exclusive region with a directional antenna are computed probabilistically and a Markov chain model in which the features of IEEE 802.15.3c and the effects of using directional antennas are incorporated is analyzed. An algorithm to find the maximal number of concurrently transmittable frames is proposed. The system throughput and the average transmission delay are obtained in closed forms. The numerical results show the impact of directional antennas on the CSMA/CA media access control (MAC) protocol. For instance, the throughput with a small beamwidth of antenna is more than ten times larger than that for an omnidirectional antenna. The overall analysis is verified by a simulation. The obtained results will be helpful in developing an MAC protocol for enhancing the performance of mmWave wireless personal area networks.

• Journal of information and communication convergence engineering
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• v.12 no.2
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• pp.109-115
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• 2014

This paper presents a concurrent channel time allocation scheme used in the reservation period for concurrent transmissions in 60-GHz wireless personal area networks (WPANs). To this end, the proposed resource allocation scheme includes an efficient method for creating a concurrent transmission group by using a table that indicates whether individual streams experience interference from other streams or not. The coordinator device calculates the number of streams that can be concurrently transmitted with each stream and groups them together on the basis of the calculation result. Then, the coordinator device allocates resources to each group such that the streams belonging to the same group can transmit data concurrently. Therefore, when the piconet coordinator (PNC) allocates the channel time to the individual groups, it should allow for maximizing the overall capacity. The performance evaluation result demonstrates that the proposed scheme outperforms the random grouping scheme in terms of the overall capacity when the beamwidth is $30^{\circ}C$ and the radiation efficiency is 0.9.

• Journal of Advanced Navigation Technology
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• v.18 no.6
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• pp.640-647
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• 2014

The WBAN technology means a short distance wireless network which provides each device's interactive communication by connecting devices inside and outside of body located within 3 meters. It is necessary to develop core technology that the WBAN middleware and application service for WBAN sensor network. A device for gathering patient's biometric information was used zigbex of Hanbaek electronics and we designed the message structure which is collected the biometric information. The gateway design and implementation for the WBAN environment. The embedded system was HBE-empos II of Hanbaek electronics and the WBAN network is implemented to BNC and BN that used for hbe-ubi-zigbex. It was confirmed that the proposed sensor gateway could be used for the interconnection of the proposed system with other networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.832-842
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• 2006

Wireless Personal Area Networks(WAPANs) are designed for short-range ad hoc connectivity among portable devices. They have gained much attention in the industry recently. One of them, High-rate WPAN, is designed to support multimedia traffic that requires high data rates. But, High-rate WPAN standards don't specify the time slot assignment scheduling method of CAT(Channel Time Allocation). So, there has been many studies regarding time slot assignment scheduling of CAT. However, present studies involve demerits about not applying various types of errors in air interlace or having a starvation of a specific DEV(data device). In this paper, we propose algorithms about supplying the intermediate channel assignment in order to avoid these demerits. This method will help other methods that use time slot assignment scheduling of CTA.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.21-26
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• 2012

As electrocardiogram (ECG) signals are generally sampled with a frequency of over 200 Hz, a method to compress diagnostic information without losing data is required to store and transmit them efficiently on a wireless personal area network (WPAN). In this paper, an ECG signal compression method for communications onWPAN, which uses feature points based on curvature, is proposed. The feature points of P, Q, R, S, and T waves, which are critical components of the ECG signal, have large curvature values compared to other vertexes. Thus, these vertexes were extracted with the proposed method, which uses local extrema of curvatures. Furthermore, in order to minimize reconstruction errors of the ECG signal, extra vertexes were added according to the iterative vertex selectionmethod. Through the experimental results on the ECG signals from Massachusetts Institute of Technology-Beth Israel hospital arrhythmia database, it was concluded that the vertexes selected by the proposed method preserved all feature points of the ECG signals. In addition, it was more efficient than the amplitude zone time epoch coding method.

• Journal of information and communication convergence engineering
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• v.11 no.1
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• pp.7-11
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• 2013

Wearable computer systems use the wireless universal serial bus (WUSB), which refers to USB technology that is merged with WiMedia physical layer and medium access control layer (PHY/MAC) technical specifications. WUSB can be applied to wireless personal area network (WPAN) applications as well as wired USB applications such as PAN. WUSB specifications have defined high-speed connections between a WUSB host and WUSB devices for compatibility with USB 2.0 specifications. In this paper, we focus on an integrated system with a WUSB over an IEEE 802.15.6 wireless body area network (WBAN) for wireless wearable computer systems. Due to the portable and wearable nature of wearable computer systems, the WUSB over IEEE 802.15.6 hierarchical medium access control (MAC) protocol has to support power saving operations and integrate WUSB transactions with WBAN traffic efficiently. In this paper, we propose a low-power hibernation technique (LHT) for WUSB over IEEE 802.15.6 hierarchical MAC to improve its energy efficiency. Simulation results show that the LHT also integrates WUSB transactions and WBAN traffic efficiently while it achieves high energy efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.838-839
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• 2016

IEEE 802.15.4 is the standard wireless link technology for low power, low cost, but long lifetime applications including wireless sensor network (WSN). Currently, whether or not IP architecture should be used in WSN over its 802.15.4 link is under dispute. Such kind of arguments may last for a long time without some convincing experimental measurements of real case performances of IP over 802.15.4 implementation, and thus prevent the advance of related research. In RFC4944, IETF proposed the 6LoWPAN specification to enable IPv6 communication over low power, wireless personal area networks. We try to alleviate the dispute and make the direction clearer to the community so as to promote further valuable research in this topic.