• KIPS Transactions on Computer and Communication Systems
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• v.3 no.4
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• pp.107-114
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• 2014

Things in the IoT(Internet of Things) make various services by exchanging information over networks. The IoT includes many types of WSNs(Wireless Sensor Networks) that consists of spatially distributed wireless sensor nodes and operates with the various purposes with useful technologies such as identification, sensing and communication. Typically, Zigbee network composed of low-cost and lowpower devices is mainly used for wide-area monitoring and remote device control systems. The IoT composed of various WSNs cannot interoperate among networks because of heterogeneous communication protocol and different data representation of each network, but can facilitate interconnection and information exchange among networks via the DDS, which is communication middleware standard that aims to enable real-time, high performance and interoperable data exchanges. In this paper, we proposed design of Zigbee Adaptor for two-way interoperation and data exchange between Zigbee network and other networks in the IoT. Zigbee Adaptor communicates with Zigbee network according to the Zigbee protocol and communicates with external networks via DDS. DDS-based Zigbee Adaptor can facilitate interoperation between a Zigbee network and external networks by systematic cooperation among its components.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.78-84
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• 2006

This paper proposes a method to endow the mobility to the Zigbee protocol which is a short distance wireless communication technology among the standards of wireless sensor networks. The Zigbee has a low price, long life battery, simple structure and connectivity. So it is a suitable standard for the short distance wireless communication of $10m{\sim}70m$. As the Zigbee does not support the mobility, additional factors should be studied to deal adeptly with the diverse change in the real field. By solving the problem that the previous connection and binding table of the Zigbee end device should be reset due to the Zigbee end device address variation when the Zigbee end device moves from the present router to another router, this paper presents the method to communicate without data loss or disconnection.

• Convergence Security Journal
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• v.8 no.2
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• pp.27-34
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• 2008

In this paper, we designed and implemented mobile object automatic system based on senor networks for telematics. For developing this system, we gather the various sensing data through wireless communication method using zigbee sensor networks and analyze them in monitoring equipment. And we enable the driver to recognize the car state information on the whole by interfacing analyzed data to telematics unit. And, we implemented automatic controller that can control temperature and humidity in car automatically by actuating air conditioner based on the data that was monitored throughout temperature sensor, humidity sensor and brightness sensor based on sensor networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12A
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• pp.971-981
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• 2009

The coordination of distributed entities and events requires time synchronization. Precision time synchronization enables a variety of extensions of applications and provides much accurate information. The IEEE 1588 precision time protocol (PTP) provides a standard method to synchronize devices in a network. This paper deals with the design and implementation of a PTP gateway to extend IEEE 1588 to Zigbee networks. The PTP gateway can not only extend IEEE 1588 to Zigbee networks but also share the same time reference using IEEE 1588 between two or more Zigbee networks. This paper also presents experiments and performance evaluation of time synchronization using the PTP gateway. Our result established a method for nodes in a network to maintain their clocks to within a 300 nanosecond offset from the reference clock of a master node via Ethernet.

• Journal of Internet Computing and Services
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• v.11 no.3
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• pp.33-41
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• 2010

The battery consumption and the wireless communication pattern were analyzed for the low power and the improvement of channel interferences between of Zigbee networks and WPAN(Wireless Personal Area Network). The communication patterns considering end device's battery saving during channel searching period were analyzed for low power consumption topology of Zigbee dynamic ad-hoc characteristics. And, the communication patterns were analyzed due to channel interferences between WLAN and Random Back off of Zigbee, too. As a result, the communication patterns of Zigbee's coordinator and end devices is alleviated for the longer battery life time of Zigbee's end device due to Zigbee's end device setting techniques.

• Journal of Information Processing Systems
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• v.9 no.1
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• pp.41-52
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• 2013

One of the obstacles preventing the Zigbee protocol from being widely used is the excessive power consumption of Zigbee devices in low bandwidth and low power requirement applications. This paper proposes a protocol that resolves the power efficiency problem. The proposed protocol reduces the power consumption of Zigbee devices in beacon-enabled networks without increasing the time taken by Zigbee peripherals to communicate with their coordinator. The proposed protocol utilizes a beacon control mechanism called a "sleep pattern," which is updated based on the previous event statistics. It determines exactly when Zigbee peripherals wake up or sleep. A simulation of the proposed protocol using realistic parameters and an experiment using commercial products yielded similar results, demonstrating that the protocol may be a solution to reduce the power consumption of Zigbee devices.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.3
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• pp.176-180
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• 2009

This paper investigates protocol architecture for a web-sensor gateway interconnecting internet and wireless sensor network, in which Zigbee sensors are connected over the IEEE802.15.4 communication protocol standard. The web-sensor gateway is to deliver data between TCP/IP and Zigbee/IEEE802.15.4 protocols, transparently. Since the gateway provides a means to remotely control and aggregate sensor data over the internet, it needs to be designed in the view point of users and in their convenience. In accordance, the common gateway interface technology satisfying users on the web browser to efficiently manage and query the sensors in the wireless sensor networks, ubiquitously, is also introduced. Finally, a simulation prototype for the web-sensor gateway is proposed and verified using OPNET simulation tool.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.203-204
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• 2007

BACnet (Building Automation and Control Networks) 은 빌딩 자동화와 컨트롤 시스템 전용의 표준 데이터 커뮤니케이션 시스템이다. BACnet은 현재 데이터링크 레이어의 전송 미디어로 5개의 유선 프로토콜을 제공하고 있다. 최근 건물 통신망에 무선 기술에 대한 수요 및 필요성이 높아지고 있다. Zigbee 는 IEEE 802.15.4를 기반으로 한 저 전력 무선 통신의 표준 프로토콜로써 유비쿼터스 센서 네트워크의 특징을 포함하고 있다. 본 연구에서는 BACnet의 데이터 링크 레이어의 확장된 무선 옵션으로 Zigbee를 포함하는 기술에 대해 연구하고 이를 기술한 실제 모델을 개발한다.

• Journal of Sensor Science and Technology
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• v.19 no.5
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• pp.342-348
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• 2010

The wireless sensor networks have been extensively researched. One of the issues in wireless sensor networks is a developing energy-efficient clustering protocol. Clustering algorithm provides an effective way to extend the lifetime of a wireless sensor networks. In this paper, we proposed an energy efficient clustering scheme by adjusting group size. In sensor network, the power consumption in data transmission between sensor nodes is strongly influenced by the distance of two nodes. And cluster size, that is the number of cluster member nodes, is also effected on energy consumption. Therefore we proposed the clustering scheme for high energy efficiency of entire sensor network by controlling cluster size according to the distance between cluster header and sink.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2B
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• pp.184-194
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• 2011

Security is critically important for smart grid networks that are usually used for the electric power network and IT environments that are opened to attacks, such as, eavesdropping, replay attacks of abnormal messages, forgery of the messages to name a few. ZigBee has emerged as a strong contender for smart grid networks. ZigBee is used for low data rate and low power wireless network applications. To deploy smart grid networks, the collected information requires protection from an adversary over the network in many cases. The security mechanism should be provided for collecting the information over the network. However, the ZigBee protocol has some security weaknesses. In this paper, these weaknesses are discussed and a method to improve security aspect of the ZigBee protocol is presented along with a comparison of the message complexity of the proposed security protocol with that of the current ZigBee protocol.