• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.249-258
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• 2013

In multi-hop ad hoc networks, multi-interface multi-channel architecture is being noticing as methodology to improve the effective bandwidth and end-to-end throughput, But since existing routing metrics designed for networks based on single-interface exactly can not reflects the nature of networks based on multi-interface multi-channel, we are not expected the effect of throughput improvement. there had been proposal of MCR that discover high throughput by using metrics such as channel diversity and interface switching cost. however, MCR have an problem that is degraded it's performance in congested networks, because it not reflects the impact of traffic load. in this paper, we propose MAMCR metric, which select high throughput paths under congested conditions by combination MCR with channel access time metric, and conform it's the effect of performance improvement by ns-2 simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.7
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• pp.612-622
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• 2013

In this paper, we propose a coding packet group-based ARQ scheme (rNC) for file delivery in wireless networks. rNC assumes multiple network coding points between the source and the destination. Each network coding point gathers and codes a group of packets according to the queue polling system. A queue polling system makes a few or several packets available for coding in a queue while polling the other queues in the system. Thus, we assuem a queue polling system at each network coding point. We call this group of packets as coded packet group. Each coding point acknowledges the reception of every code packet group to its previous coding point for reliable delivery. Thus, the intermediate coding points including the source can release its buffer before the packet is delivered to the destination. To guarantee the ultimate file delivery to the destination, the destination sends acknowledgement to the sender. We evaluate our proposed scheme using ns-2 and compare the performance with CodeCast. The results show that rNC works better than CodeCast in terms of packet delivery ratio and control overhead in unreliable wireless networks.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.9
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• pp.1-11
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• 2002

The optimal AP placement for wireless LAN is important factor for improving service quality and reducing cost. Decision of AP placement is depend on radio signal strength, environment factor and logical area property, which is user's frequently posed place. This paper proposes optimal multiple AP placement method based on radio prediction tool. The proposed method can get flexibility in multiple AP placement using user defined parameter and the optimization design uses Hopfield network algorithm. And path-loss model is used for one of radion prediction model. The result of simulation shows that it is efficiently reduces the process to find optimal AP placement. And the proposed optimization design of multiple AP placement can improve service quality for wireless LAN.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.673-675
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• 2004

Mobile Ad-Hoc Network는 base station에 의존하지 않는 다중 홉 무선 네트워크이다. 이 기술은 동적 주소할당을 위해 일반적으로 사용되는 DHCP 프로토콜이나 경로 메시지를 전달하는 라우터를 사용하지 않고 통신에 참가하는 모든 노드가 라우터 역할을 함으로써 네트워크를 구성한다. 현재 제안되고 있는 라우팅 프로토콜은 모두 네트워크 형성 이전의 노드 설정을 가정한다. MANET의 상용화 관점에서 본 논문은 이동 노드의 주소 할당 및 설정을 위해 zeroconfiguration[2]과 MANETconf[3] 및 네 가지 종류의 주소할당 메커니즘의 특징을 살펴보고 상태 유지필요성, 주소충돌가능성, 알고리즘 복잡성, 통신오버헤드, 확장성 관점에서 비교분석 하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.663-666
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• 2008

본 논문에서는 무선 센서네트워크에 적합한 백본을 형성하여 특정 노드 집합들만 라우팅에 참여하게 함으로써 데이터를 전달하기 위한 오버헤드와 깨어있는 노드의 수를 최소화한다. 이때 백본을 형성하는 노드들은 일반 노드에 비해서 에너지 소모가 크므로 노드의 잔여에너지와 차수를 고려하여 강건한 백본을 형성하여 네트워크의 라이프타임을 증가시키는 것이 중요하다. 그러므로 본 논문에서는 에너지레벨이 높은 노드를 클러스터헤드로 선정해서 강건한 백본을 형성하고, 헤더 주변에 많은 노드들을 배치하여 패킷전달의 역할을 분산함으로써 네트워크 라이프타임을 늘린다. 시뮬레이션 결과에서 제안 알고리즘은 기존 연구에 비해 클러스터헤드의 잔여에너지측면에서 약 58.6%, 차수측면에서 약 79.42%의 성능 향상을 보인다.

• Journal of Advanced Navigation Technology
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• v.18 no.3
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• pp.236-241
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• 2014

In a mobile ad hoc networks, multi-hop transmission is used to transfer data from source node to destination node and the routing protocol is the one of the important technical issues. The links between nodes can be unstable due to the changes of node location and channel conditions, and it can induce link error. To solve this problem, multipath routing was proposed. Multipath routing can reduce the data congestion and increase data throughput. In the multipath routing, however, each path can be interfered by the other path, and it can aggravate network performance. In this paper, we propose the multipath routing technique in the multi-rate MANET. The proposed multipath routing can avoid interference without the knowledge of node location. Simulation results show that the proposed multipath routing can reduce transmission delay and error.

• Journal of KIISE:Information Networking
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• v.36 no.6
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• pp.528-535
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• 2009

This paper proposes a mechanism to increase performance using cooperative communications in IEEE 802.11 environment. Existing algorithms use one relay between a source and a destination, which is a 2 hop relay. The proposed algorithm utilizes more than one relay to complement inefficiency of using one relay. In the proposed mechanism, an AP manages network information (rate), which is used to select relays of a source by the AP. The AP notifies the selected relays to the source and neighbor nodes, and the source transmits data to the relays for cooperative communications. Moreover, relays are given to have an opportunity to send its own data right after relaying the source's data. So relays are compensated for the power to send the source's data and overall throughput is improved.

• Journal of Internet Computing and Services
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• v.23 no.5
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• pp.1-7
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• 2022

IoT technology that utilizes wireless body area networks (WBAN) and biosensors is an important field in the health industry to minimize resources and monitor patients. In order to integrate IoT and WBAN, a cooperative protocol that constitutes WBAN's limited sensor nodes and rapid routing for efficient data transmission is required. In this paper we propose an we propose an energy efficient and cooperative link energy-efficient routing strategy(LEERS) to solve the problems of redundant data transmission detection and limited network sensor lifetime extention. The proposed scheme considers the hop count node congestion level towards the residual energy sink and bandwidth and parameters. In addition, by determining the path cost function and providing effective multi-hop routing, it is shown that the existing method is improved in terms of residual energy and throughput

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.9
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• pp.774-783
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• 2012

A simple, accurate, secure, long-lasting, and portable hybrid positioning system is proposed and designed in this paper. It consists of a lighting LED that generates visible light data corresponding to position information of a target and a Zigbee wireless network communication module with low power, security, and service area expansion characteristics. Under an indoor environment where there is 23.62m distance between an observer and the target, the presented hybrid positioning system is tested and is verified with the functions of Zigbee three hop wireless networking and visible light communication (VLC) scheme. The test results are analyzed and discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2815-2822
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• 2011

Clustering method in wireless sensor networks is the technique that forms the cluster to aggregate the data and transmit them at the same time that they can use the energy efficiently. In this paper, I propose the hierarchical unequal clustering method using cluster group model. This divides the entire network into two layers. The data aggregated from layer 2 consisted of cluster group is sent to layer 1, after re-aggregation the total data is sent to base station. This method decreases whole energy consumption by using cluster group model with multi-hop communication architecture. Hot spot problem can be solved by establishing unequal cluster. I also show that proposed hierarchical unequal clustering method is better than previous clustering method at the point of network energy efficiency.