• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.9
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• pp.825-833
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• 2016

This paper introduces a direct-conversion CMOS RF transmitter for the IEEE 802.15.4 standard with a low-power high-gain up-conversion mixer designed in $0.18{\mu}m$ process. The designed RF DCT(Direct Conversion Transmitter) is composed of differential DAC(Digital to Analog Converter), passive low-pass filter, quadrature active mixer and drive amplifier. The most important characteristic in designing RF DCT is to satisfy the 2.4 GHz Zigbee standard in low power. The quadrature active mixer inside the proposed RF DCT provides enough high gain as well as sufficient linearity using a gain boosting technique. The measurement results for the proposed transmitter show very low power consumption of 7.8 mA, output power more than 0 dBm and ACPR (Adjacent Channel Power Ratio) of -30 dBc.

• The Journal of the Korea Contents Association
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• v.10 no.1
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• pp.27-36
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• 2010

In wireless networks environment, there are attempts for constructing systems through which we can monitor and control various electronic devices used in large buildings at remoteness by using Zigbee protocol. Since address assignment method of DAA in Zigbee has a depth restriction, we cannot construct a network in large buildings. And also communication failures are frequent in a large network since broadcast storm can be occurred due to frequent broadcasts among a lot of nodes at AODV routing used in Zigbee. In order to solve these problems, in this paper, we propose a novel protocol which has improved the restriction of depth by using a fixed address assignment method, and has enhanced the broadcast occurrence by devising a static routing method to a packet movement between floors. Regardless of entire network, additionally, this was to enable internal communication reliably by composing an independent PAN. Specially, in this paper, we implemented the proposed wireless protocol and proved stability and practicality through experiment appliances of control of devices established in a large building.

• Journal of Information Technology Services
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• v.10 no.1
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• pp.105-116
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• 2011

With recent spotlight on the, uniquitous computing technology, the need for object of indentification and location infrastructure has increased. Such GPS technolgy must utilize IEEE 802.15.4 Zigbee used for existing wireless sensor network infra as a basice element for user's context-awareness in a uniquitous environement, for effectiveness.Such real-time GPS service is provided in the internal environment where the user would actually are and most high-rise buildlings apply. Underthe assumption, the real-time GPS technology is seperated by each floor, and signals do not get transmitted to other floors, the application on one floor within the high-rise buildling was conducted. This study intends to suggest a floor detection algorithm using IEE 802.15.3/Zigbee's RSSI which supports the accuracy within a couple of meters for the user's the movement between the floors in high-rise buildings in a complex environment. It proposes an floor detection algorithm using IEEE 802.15.4/Zigbee's RSSI which provides accuracy within a radius of few meters for the users movement between the floors for real-time location tracking within high-rise building in a cmoplex environment. Furthermore, for more accurate real-time location tracking, it suggests an algorithm for real-time location tracking using IEEE 802.15.4a/Zigbee's CSS technology based on triangulation. Based on the suggested algorithm, it designs a hybrid real-time location tracking service system in a high-rise buildling and test its functions.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.223-228
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• 2021

In this paper, we proposed a slot-type antenna with microstrip feed embedded in a PCB for Zigbee communication (2.4 ~ 2.484 GHz). The proposed antenna is designed on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of 50×65 mm². Through simulations, trends of design parameters are analyzed and optimized, and the proposed antenna composed with three slots satisfy the frequency band. The measured impedance bandwidths (|S₁₁| ≤ -10 dB) of fabricated antenna are 900 MHz (2 ~ 2.9 GHz) in Zigbee frequency band. In addition, the radiation pattern showed omnidirectional characteristics for E and H-planes, and the gain of antenna in Zigbee frequency band was 1.782 dBi.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.43-44
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• 2008

본 논문에서는 Weighted Cenrtoid Localization(WCL) 알고리즘을 적용하여, 고정 노드 (Anchors) 사이의 측정된 수신 신호 강도(RSSI)로 Zigbee 실내 위치 인식 시스템을 구현하였다. 센서 노드의 위치는 RSSI에 의해 선택된 가상 고정 노드에 WCL을 적용하여 결정한다. WCL에서 부여하는 가중치는 고정 노드와 RSSI 센서 노드 위치의 거리에 대한 함수이며, 고정 노드 간의 측정된 RSSI 값으로 구한다. 고정 노드 간의 RSSI로 가상 고정 노드를 이용한 WCL은 기존의 방식에서 사용되는 고정 노드의 수를 줄이고, 측정 대상의 위치 정확도를 측정된 RSSI 값만으로 추정한 위치보다 7.8% 향상되는 것을 확인 하였다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.265-268
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• 2006

본 논문에서는 댁내망에서 무선 홈네트워크 기기 제어에 있어서의 트래픽 암호화 및 기기인증 등의 보안 문제 연구를 위한 플랫폼을 개발하였다. 우선 근거리 무선 통신 표준으로 자리잡고 있는 Zigbee를 적용한 도어락과 저가의 홈게이트웨이를 개발하고 다양한 암호 알고리즘을 탑재할 수 있도록 하였다. 또한 AES와 HGHT를 탑재하여 기기인증과 트래픽에 대한 암호화가 가능하도록 하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.410-411
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• 2011

본 논문에서는 태양광 전원, 배터리, 마이크로터빈, 스마트 홈 등 다양한 목적과 특성을 가진 요소로 구성된 마이크로그리드를 효율적으로 제어, 관리하기 위한 분산 지능형 제어원리를 제안한다. 기존의 중앙집중식 제어원리는 중앙에서 전체 시스템에 대한 정보를 취득하여 운영에 대한 의사결정을 독점하는 구조였다면 제안하는 원리는 마이크로그리드의 구성요소가 각각 지능형 에이전트를 기반으로 스스로 데이터를 취득하고 이웃 에이전트와의 대화와 협조를 통해 분산제어를 수행하는 방식이다. 각 에이전트 사이는 근거리 무선통신 방식인 Zigbee를 이용하였고 마이크로그리드를 실시간으로 해석하기 위하여 MATLAB 기반의 실시간 시뮬레이터를 이용하였다. 실시간 마이크로그리드 시뮬레이션 모델과 에이전트 역할을 하는 마이크로 컨트롤러를 연계하여 Hardware-in-the-loop 기반의 데모시스템을 구축하였고 제안하는 원리에 대해 검증하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.138-139
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• 2017

세계적으로 에너지 과다 사용으로 인한 비상사태가 발생하면서 에너지 절감, 그린 에너지에 대한 관심이 증가하고 있다. 특히 블루투스 기반의 네트워크 구성을 통해 중앙 조명 제어가 이루어지고 있다. 그러나 블루투스는 저전력 기술 중 높은 전력을 소모하기 때문에 조명기기가 증가할수록 전력사용량이 증가하기 때문에 저전력을 유지하기 어렵다는 문제점이 있다. 따라서 본 논문에서는 Zigbee 기술을 기반으로 조명기기를 제어할 수 있는 시스템을 설계하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1071-1076
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• 2015

This paper proposed an efficient algorithm for tension sensing smart fence system with wireless sensor transmission module installation and alarming services. The wired transmission system demonstrates high accuracy and low latency, but the cost is expensive and transmission error may occur. For these reasons, this paper presented to use wireless transmission communication using Zigbee module technology in order to decrease delay and latency and solve the battery issues.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2361-2366
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• 2009

Usually, it is possible for human administrator to control the facilities manually or automatically using sensors in order to manage the fixed electricity facilities. However, it is difficult to collect the status data of those facilities in the central management system. In this paper, we propose the electricity facility management system to collect the status of facilities using the Zigbee networks. the proposed system exploits the various types of sensors, such as motion, heat, optical, etc, to measure the states of the facilities.