• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.91-96
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• 2019

For a wireless sensor network in general, efficient routing decision is important because wireless connections are not stable, sensitive to external interference, and topology changes dynamically. RPL standard of IETF is not flexible to various environmental changes and causes packet loss and delay due to topological imbalance. Sending packets through multipath can partially remedy this problem. The multipath routing, however, can introduce significant delay overhead by allocating unnecessary timeslots. This paper proposes an RPL using multipath adaptively according to network conditions. We show by simulations that the proposed algorithm is more efficient than the basic RPL and the multipath RPL.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1089-1096
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• 2019

Recently, small-scale IoT services using a small amount of information through low-performance computing have been spread. It requires low cost, low-power, and long-distance communication technologies with wide communication radius, relatively low power consumption. This paper proposes a MAC layer and routing protocol that supports multi-hop transmission in small-scale IoT environment distributed over a large area based on LoRa communication and delivering a small amount of sensing data. The terminal node is mobile and the communication type provides bidirectional transmission between the terminal node and the network application server. By applying the proposed protocol, a production line monitoring system for smart factory was implemented. It was confirmed that the basic monitoring functions are normally performed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.117-120
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• 2002

Bluetooth uses baseband of 2.4G ISM and composes radio Ad Hoc network based on Ad Hoc wireless connectivity which it used low power and low complexity solution. Bluetooth designed as can play detect, connect, discover service by surrounding other device even if users do not get acquainted all to Bluetooth. This paper operate wish to recognize mobility to routing algorithm how communication method and radio network in Bluetooth.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.11-19
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• 2010

ZigBee is a standard for wireless personal area networks(WPANs) based on the IEEE 802.15.4 standard. It has been developed for low cost and low power consumption. There are two alternative routing schemes that have been proposed for the ZigBee standard: Ad-hoc On-Demand Distance Vector(AODV) and tree routing. The tree routing forwards packets from sensors to a sink node based on the parent-child relationships established by the IEEE 802.15.4 MAC topology formation procedure. In order to join the network, a sensor node chooses an existing node with the strongest RSSI(Received signal strength indicator) signal as a parent node. Therefore, some nodes carry a large amount of traffic load and exhaust their energy rapidly. To overcome this problem, we introduce a new metric based on link quality and traffic load for load balancing. Instead of the strength of RSSI, the proposed scheme uses the new metric to choose a parent node during the topology formation procedure. Extensive simulation results using TOSSIM(TinyOS mote SIMulator) show that the CFR scheme outperforms well in comparison to the conventional tree routing scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.712-721
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• 2012

In this paper, we propose an Enhanced cross-layer Geographic Forwarding (EGF) protocol for wireless sensor networks (WSNs). EGF uses an optimal back-off time to make the packet forwarding decisions using only source and destination's location information and energy cost without information about neighbor nodes' location or the number of one hop neighbor nodes. EGF is also a cross-layer protocol by combining efficient asynchronous MAC and geographic routing protocol. The proposed protocol can find optimal next hop location quickly without broadcasting node's location update and with minimizing overhead. In our performance evaluation, EGF has better performance in terms of packet success ratio, energy efficiency and end-to-end delay in wireless sensor networks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.517-520
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• 2009

Healthcare application system has been actively researched to apply WSN technology to healthcare area with a mobile sensor node of low cost, low power, and small size. Sensor node has the problem for transmission range of RF power and time delay of the wireless routing connectivity between sensor nodes. In this paper, we proposes a new method utilizing mobile sensor nodes with relay sensor nodes for quick network routing changing using query technique in healthcare system. A query processor to control and manage the routing changing of sensor nodes in a wireless sensor network was designed and implemented. The user's PC transmits the beacon message which will change the quick link routing according to activity status of patient in wireless sensor network. We describe the implementation for query protocol that is very effective of power saving between sensor nodes.

• Electronics and Telecommunications Trends
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• v.20 no.1 s.91
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• pp.93-99
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• 2005

최근 새롭게 등장한 유비쿼터스 컴퓨팅 환경은 기존의 컴퓨팅 환경과는 다르게 통신 인프라가 없는 환경에서도 동작이 가능한 저전력 소출력의 무선 센서간의 네트워크를 형성하고 이들간의 정보 유통이 이루어진다. 이러한 u-센서 네트워크는 Ad-hoc 성격뿐만 아니라 무선이 가지는 방송 특성으로 센서정보의 도청, 비정상적 패킷의 유통, 메시지의 재사용 등의 데이터 위. 변조 문제와 네트워크 전체를 마비시킬 수 있는 서비스 거부 등의 공격에 쉽게 노출된다. 본 고에서는 센서 네트워크에서의 정보보호요구사항과 구조, 키 관리의 문제 및 라우팅과 수집된 데이터를 집계하는 데 있어서의 보안 이슈와 동향에 대해 소개한다.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1043-1048
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• 2005

As sensor network is drawing more attention than ever before due to the development of sensors and the technology of communications, various routing-algorithms, to realize a sensor node with low-power and a miniature size, is being introduced in the field. This paper is to discuss a way to find an optimal path by changing a routing- algorithm adequately according to environmental changes. This is also to suggest an appropriate sensor network model in the ubiquitous aera. The result from the experiment that we conducted showed us that as we suggested, an algorithm, changing and adapting itself to each different environment, operated more stably and transmitted data more effectively than the current fixed one. And it was also confirmed that this type of algorithm can provide low-power management, which is very important in sensor network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.412-414
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• 2018

본 논문에서는 서비스 기반 자율-구성 네트워크 구축 시 활용 가능한 새로운 주소 설정 기법을 제안하다. 제안하는 주소 설정 기법은 IPv6를 기반으로 제안되었다. 일반적인 IPv6 구조는 자율-구성 네트워크를 구성하는 주소 설정 방식으로는 부족하다. 이유는 일반적인 IPv6 구조는 글로벌 주소에 개념을 가지고 있으며 주소에 대한 중복성 평가에 대한 오버헤드가 크다. 이는 자원-제약적 노드로 구성되는 사물인터넷 환경에 사용할 시 저전력 및 노드 메모리 문제를 유발할 수 있다. 또한 노드에 서비스를 정의할 수 있는 필드가 존재하지 않으므로 이를 위한 필드가 추가적으로 필요하다. 따라서 본 논문에서는 NAT 개념을 적용하여 만들어진 IPv6 기반의 ULA 주소 체계를 활용한 경량화 주소 설정기법을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.759-764
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• 2006

센서 네트워크는 배터리 교체가 어려운 저가의 소형, 저전력 센서 노드들로 구성되며 멀티 홉 방식으로 통신하기 때문에 센서 네트워크 수명을 연장하기 위한 라우트 선정 방법은 중요하다. 그러나 다수의 라우팅 기법은 노드의 정적인 상태 정보만 이용하여 라우트를 선택하기 때문에 링크 상태에 따른 데이터 손실이나 특정 노드의 에너지 부족에 의해 발생하는 패스 손실과 같은 동적인 상황은 반영하지 못하는 문제점이 있다. 본 논문에서는 이웃 노드들의 상황을 인지하여 가장 데이터를 전달 받기 좋은 상황에 있는 노드를 라우트로 선택하는 기법을 제안하며, 제안하는 기법을 SARS(Situation Aware Route Selection)라 부르겠다. 제안하는 SARS는 이웃 노드들의 상황을 고려하여 라우트를 선택하기 때문에 데이터 손실이나 패스 손실에 의한 재전송 노드의 수를 최소화 할 수 있고, 이를 통해 센서 네트워크 수명이 연장되는 효과를 얻을 수 있을 것으로 기대된다.