• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.32-39
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• 2006

5.8GHz DSRC(Dedicated Short Range Communications) is a short to medium range communications service that supports both public safety and private operations in roadside to vehicle and vehicle communication. However the 5.8GHz frequency may cause the shadowing effect or communication blocking problem when there is an obstacle or another vehicle between RSE (Road Side Equipment) and OBE (On Board Equipment). In this paper, to solve this problem of the 5.8GHz DSRC, we propose a relay protocol based on the standard of DSRC radio communication between RSE and OBE in the 5.8GHz band made by TTA (Telecommunication Technology Association). By using the proposed relay protocol to DSRC system and intervehicle communication, we also consider a fixed relay protocol and mobile relay protocol. We expect to apply this relay protocol for the DSRC intervehicle communication and video communication between drivers and safe distance among vehicles in the near future.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.66-70
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• 2001

근거리 무선 통신 기술의 하나인 블루투스 기술은 최근 많은 연구와 개발이 이루어지고 있으며, 블루투스 프로토콜 스택의 개발은 블루투스 기술의 응용을 위한 기술적 독립을 의미한다. 이에 대해 본 논문에서는 블루투스 하드웨어와 호스트 사이의 인터페이스 계층으로 블루투스 프로토콜의 HCI 계층을 설계하였고, 일련의 실험을 통하여 기본 동작 과정 및 기 개발된 타사의 블루투스 어뎁터와의 동작 호환성도 연구해 보았다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.3-10
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• 2012

The visible light communication takes advantages of LED and PD for communication and is considered as a next generation wireless communication technology. It can support variety indoor applications. Especially, Visible LAN service has drawn much attention due to high data rate and no interference with existing WPAN system as well as high efficiency in illumination. However, existing MAC protocol occurs a high communication delay due to uplink collision and backoff time. In this paper, to reduce packet delay, we propose an enhanced MAC protocol based on FDD where the time difference between uplink frame and downlink frame transmission is utilized. Through computer simulations, we verified that the proposed MAC protocol outperforms the existing MAC protocol in terms of average packet delay.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.336-346
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• 2001

A wireless ad-hoc network is a temporal network formed by a collection of wireless mobile nodes without the aid of any existing network infrastnlcture or centralized administration. Currently, numerous routing protocols have been developed for changing messages between nodes in a wireless ad-hoc network. Applications of wireless ad-hoc network technology are various and proper routing protocol must be used according to application domain or network size. In a wireless ad-hoc network. some hosts want services from fixed networks. For supporting such services, it is necessary to interconnect wireless ad-hoc networks and fixed networks. The DSMIHDynamic Source Multipath Routing) protocol, proposed in this paper, focuses on supporting seamless communication services between the nodes within a wireless ad-hoc network and providing fixed networks to the mobile hosts in wireless an-hoc networks. In DSMR protocol, each node need not broadcast routing messages periodically. and mobile hosts that to send data packets initiate route request and route establishment procedure. By maintaining multiple paths in each node. faster route re-establishment is also possible in our scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1033-1036
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• 2013

A study about collision resolution is needed because huge file, video and multimedia information are transmitted to wireless LAN. CSMA/CR protocol guarantees fairness, but doesn't consider QoS. To practicalize CSMA/CR protocol in saturation fully-connected single hop network environments, this paper proposes method of collision compensation. previous CSMA/CR protocol chooses CR Slot only considering fairness, but this paper chooses front CR Slot for compensation of collision to station experiencing collisions. The station transmits jam signal and has channel priority of transmission. So transmitting efficiency and successful transmission probability rise. This proposed simple method can offer benefit to station experiencing collisions without additional hardware cost.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.43-46
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• 2008

During communication between wireless users, disconnection may occur during the handover process. The high handover latency during the process of handover degrades the service quality of the wireless communications. This problem becomes more crucial if the operation network is transmitting real-time multimedia applications. This paper presents our work on the interworking of protocols in IPv6 mobility management which aims to explore the means to reduce the handover latency. We propose Reducing Handover Latency through Protocols over IPv6 mobility management.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.803-808
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• 2010

Wireless Sensor Networks are widely applied for organizing real-time monitoring systems. Unlike general kinds of sensor networks, it is important to preferential send emergency data to the control server when urgent events are occurred. But IEEE 802.15.4 MAC protocol which is generally deployed for wireless sensor network does not support algorithm for urgency data handling. Therefore, we proposed a MAC protocol which consider the priority for the urgency data handling.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.304-305
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• 2019

Wireless sensor networks are used in various applications due to the flexibility of network. In particular, the energy harvesting wireless sensor network (EH-WSN) has been introduced to solve the power limitation problem, and the application range of the sensor network is further expanded. In order to transmit the sensed data to the destination node, the MAC protocol considering the power of the nodes has been studied. The power situation and the urgency of the data are important elements of data transmission, and a medium access control protocol that comprehensively considers data urgency and power of nodes is required. In this paper, we propose a medium access control protocol which can select relay nodes according to power situation and urgency of data.

• Journal of the Korea Society of Computer and Information
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• v.19 no.7
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• pp.59-70
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• 2014

This paper propose a new wireless multi-hop routing protocol that takes the hierarchical mesh of the hybrid WMN into account. WMN that is possible to provide various applications of wireless networks still has many open issues that should be solved despite the studies carried out over a decade. Especially, in routing protocol area, a problem degrading the routing efficiency by applying one of the routing protocols, which are designed for the MANET, to the hybrid WMN be solved above all. For the improvement of the routing performance, both good routing protocol and metric are essential. However, the recent studies are only concentrated in routing metric by use of the cross-layer design. Therefore, this paper is dedicated to the routing protocol that is essential for the performance of the routing but needed more studies. The proposed protocol in this paper is reactive, and designed to reorganize the hybrid WMN with several pseudo domains, and carry out domain-based route decision. By the simulation result for the performance analysis of the proposed protocol, the average delay for the route decision was decreased by 43% compared to AODV that is the typical reactive protocol.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.1295-1298
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• 2006

일반적인 센서 네트워크 환경과 달리 이동성을 중시하는 환경에서의 무선 센서 네트워크는 에너지 효율성, 동적 자기구성, 이동성에 적합하도록 개발되어야 한다. 이러한 환경에서의 센서 네트워크 응용은 고정 노드와 이동 노드가 혼재되어 있는 것이 일반적이다. 본 논문에서는 이러한 이동 노드 지원을 위한 'LEACH-Mobile' 프로토콜을 제안한다. LEACH-Mobile프로토콜은 노드의 움직임에 따라 토폴로지가 변화할 때, 이동하는 노드가TDMA 스케줄에 따른 시간 슬롯에서 특정 클러스터 헤드 노드와 통신이 가능한지의 여부로서 클러스터의 멤버가 될 노드를 결정하고 클러스터를 재구성한다. LEACH-Mobile 프로토콜의 시뮬레이션 결과는 이동 노드가 증가함에 따라 이동성을 지원하지 않는 기존의 LEACH 프로토콜에 비해 데이터 전송 성공률 면에서 명확한 성능 향상을 가져오는 것을 보여준다.