• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.1-7
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• 2010

Network Centric Warfare(NCW) is becoming a prominent concept in the current trend of warfare. To support high quality communication between strategic/tactical units in the concept of NCW, Tactical Airborne Networks are likely to be constructed in the near future to take part in the NCW. In these Tactical Airborne Networks with dynamic topology variations due to very high mobility of participants nodes, more efficient and reliable neighbor discovery protocols are needed. This paper presents the adaptive HELLO message scheduling algorithm for Tactical Airborne Network using directional antennas. The purposed algorithm can reduce the overhead of periodic HELLO message transfer, while guaranteeing successful data transmission. We concluded a mathematical analysis and simulation studies using Qualnet 4.5 for evaluation the performance and efficiency of the proposed scheme.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.277-279
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• 2005

무선 멀티 홉 네트워크는 기지국 없이 중간의 무선 단말기를 경유해서 메세지를 전송하므로 무선 단말기의 전력 상태나 이동에 따라 그 토폴로지가 자주 변한다. 따라서 목적지까지 경로를 탐색하고 유지하기 위해 효율적인 경로 탐색 기법에 대한 연구가 필요하다. 그러나 경로 탐색 과정은 경로 탐색 메세지를 네트워크 전체로 전파하는 플러딩으로 인해 네트워크의 처리율을 크게 감소시킨다. 플러딩으로 발생하는 트래픽을 억제하기 위해 제안된 선별적인 플러딩 기법 중 이웃 노드 정보에 기반 한 접근 방식은 비교적 정확하게 재전송에 필요한 노드를 선별할 수 있으나 HELLO 패킷을 주기적으로 발생시켜야 한다. 본 논문은 이웃 노드의 맥(MAC) 계층에서 발생하는 제어 메세지를 청취해서 이웃 노드의 트래픽 정보를 수집하고 이것을 이용해서 재전송에 필요한 노드를 선별하는 기법을 제안 한다.

• Journal of Digital Contents Society
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• v.18 no.4
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• pp.753-760
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• 2017

In this paper, we propose a new method to improve the performance of a Quorum-based NDP (Neighbor Discovery Protocol) in heterogeneous wireless sensor networks. It creates a new set of discovery schedules by combining two different Quorum-based matrices. The original Quorum-based schedule guarantees only two overlapping active slots with a cycle, but the newly created matrix greatly increases the chance of neighbor discovery. Therefore, although the size of the combined matrix of the proposed method increases, the number of discovery chances with neighboring nodes considerably increases, and the new approach is superior to the original Quorum-based neighbor node discovery protocol. In this study, we compares the performance of the proposed method to the Quorum-based protocols such as SearchLight and Hedis using TOSSIM. We assume all sensor nodes operates in a different duty cycle in the experiment. The experimental results show that the proposed algorithm is superior to other Quorum-based methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6A
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• pp.85-96
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• 2008

Neighbor Discovery(ND) protocol is used to exchange an information of the neighboring nodes on the same link in the IPv6 protocol environment. For protecting the ND protocol, firstly utilizing Authentication Header(AH) of the IPsec protocol was proposed. But the method has some problems-uses of key exchange protocol is not available and it is hard to distribute manual keys. And then secondly the SEcure Neighbor Discovery(SEND) protocol which protects all of the ND message with digital signature was proposed. However, the digital signature technology on the basis of public key cryptography system is commonly known as requiring high cost, therefore it is expected that there is performance degradation in terms of the availability. In the paper, to improve performance of the SEND protocol, we proposed a modified CGA(Cryptographically Generated Address) which is made by additionally adding MAC(Media Access Control) address to the input of the hash function. Also, we proposed cache mechanism. We compared performance of the methods by experimentation.

• Journal of the Korea Society of Computer and Information
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• v.14 no.12
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• pp.109-117
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• 2009

In this paper, we propose an efficient service discovery scheme that combines peer-to-peer caching advertisement and node ID-based selective forwarding service requests. P2P caching advertisement quickly spreads available service information and reduces average response hop count since service information store in neighbor node cache. In addition, node ID-based service requests can minimize network transmission delay and can reduce network load since do not broadcast to all neighbor node. Proposed scheme does not require a central lookup server or registry and not rely on flooding that create a number of transmission messages. Simulation results show that proposed scheme improved network loads and response times since reduce a lot of messages and reduce average response hop counts using adaptive selective nodes among neighbor nodes compared to traditional flooding-based protocol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1873-1882
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• 2009

In the ad-hoc mode of IEEE 802.11 standard, beacon is used for power control and network alarming between each node, and also it is for the synchronization in controlling network as PCF. However beacon is also used to inform the neighbor nodes of itself except for original purpose in the environment of IEEE 802.11s. For this, the existing beacon's transmission mechanism can't perform a function in full. In this paper, we suggest much faster neighbor discovery reducing network congestion caused by beacon through modification of beacon transmission mechanism. And we will show that suggesting algorithm more faster full neighbor discovery than traditional neighbor discovery using for IEEE 802.11 through simulation and test in real ad-hoc network.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.336-339
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• 2009

본 논문에서는 최단 경로 탐색 및 거리 계산의 필요성을 가지고 근사 인덱싱 방법의 후처리 부분을 제안한다. 근사 인덱싱 방법이란 오프라인에서 네트워크 공간상의 객체들을 유클리드 공간 상의 절대 좌표로 사상하여 인덱싱한 후, k-최근접 이웃 질의를 처리하는 방법이다. 그러나 기존 연구는 질의 점으로부터 각 정적 객체까지의 경로를 탐색해주지 않을 뿐만 아니라 착오 기각이 발생한다. 따라서 본 논문에서는 질의 점으로부터 k개의 정적 객체까지의 경로를 효과적으로 탐색할 수 있는 방법을 제안한다. 또한, 이 방법을 통하여 착오 기각 역시 완화시킬 수 있는 방법을 제안한다. 실험을 통하여 제안하는 방법이 기존 경로 탐색 기법들에 비해 노드 탐색 횟수 및 실행 성능이 크게 향상시킨 것으로 나타났다.

• The KIPS Transactions:PartC
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• v.15C no.3
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• pp.213-220
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• 2008

A MANET is an autonomous, infrastructureless system that consists of mobile nodes. In MANET, on-demand routing protocols are usually used because network topology changes frequently. The current approach in case of broken routes is to flag an error and re-initiate route discovery either at the source or at the intermediate node. Repairing these broken links is a costly affair in terms of routing overhead and delay involved. Therefore, this paper propose a NAODV(Neighbor-aware AODV) protocol that stands on the basis of an AODV. It sets up the route rapidly if it operates for setting the route directly by using sequence number of neighbor nodes without re-search the route when the route to destination node is broken. Also, it reduces loss of packets. We use NS-2 for the computer simulation and validate that the proposed scheme is better than general AODV in terms of packet delivery ratio and average end-to-end delay. Also, when the proposed protocol is applied to the large ad-hoc network with multiple nodes, the performance is more efficient.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.4
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• pp.32-39
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• 2006

MANET is a dynamically reconfigurable wireless network with no fixed infrastructure (base station, or AP). In order to provide the data service in MANET, we need an efficient routing protocol to deliver the data to the wanted destination at a mobile node. A method of routing protocols called reactive routing protocol has recently got attention because of their low routing overhead. But a method of flooding broadcasts the packet to all of its neighbors. For this reason, each of the node has high routing overhead to route and keep path discovery. Accordingly in this paper, I propose an adaptive flooding scheme using N-hop look-ahead in MANET, md an optimal N value of doing flooding the packet to limited area. Because of being basically ignorant about topological changes, each of the node did not spontaneously cope with path alteration. But an efficient flooding scheme applying N-hop look-ahead is more resilient to topology changes than traditional algorithms. And also with this efficient flooding scheme, the simulation results demonstrate excellent reduction of routing overhead.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.879-888
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• 2004

Ad Node transmits packets to a destination node using routing function of intermediate nodes on the path in Ad Hoc networks. When the link to a next hop node in a path is broken due to the next hop node's mobility, a new route search process is required for continuing packets transmission. The node which recognizes link fault starts a local route recovery or the source node starts a new route search in the on demand routing protocol AODV. In this case, the new route search or the local route search brings packet delays and bad QoSs by packet delay. We propose RPAODV that the node predicts a link fault selects a possible node in neighbor nodes as a new next hop node for the path. The proposed protocol can avoid path faults and improve QoS.