• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.83-86
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• 2002

In this paper while a router is routing all packet to the next hop, it inspects whether there is congestion on this current hop router or not and if the router discovers that it has some congestion, it informs that the packet is experienced to congestion. The packet arrived to next hop including some information about the congestion is processed first and it has wider bandwidth than another packet The amount of congestion is recorded to the DS field of IP header by congestion experience level. In the next hop when the packet including the congestion information is routed, the standard packet dropping ratio of the current router is changed in proportion to congestion experience that is recorded in IP header on of that. When the packet that has experienced congestion before is arrived, the router extends the drop threshold value not to drop the packet. It mean that transferring the audio or video stream, if the packet is already experienced the congestion in another hop, the router can provide the better service quality about 15∼25% than another.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.191-198
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• 2007

A mobile ad-hoc network (MANET) is an autonomous, infrastructure-less system that consists of mobile nodes. In MANET, on demand routing protocols are usually used because network topology changes frequently. AODV, which is a representative on demand routing protocol, operates using the routing table of each node that includes next hop of a route for forwarding packets. It maintains the established route if there is not an expiration of route or any link break. In the paper, we propose a partially adaptive route maintenance scheme (AODV-PA) based on AODV, which provides dynamic route modification of initial route for selecting the effective route using not only next hop but also next-hop of next-hop (i.e. 2-hop next node) acquired through route discovery process. In addition, the proposed scheme additionally manages the routing table for preventing exceptional link breaks by route modification using HELLO messages. 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, latency, routing overhead.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.6
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• pp.558-564
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• 2013

Wireless sensor networks (WSNs) contain limited energy resources and are left in open environments. Since these sensor nodes are self-operated, attacks such as sinkhole attacks are possible as they can be compromised by an adversary. The sinkhole attack may cause to change initially constructed routing paths, and capture of significant information at the compromised node. A localized encryption and authentication protocol (LEAP) has been proposed to authenticate packets and node states by using four types of keys against the sinkhole attack. Even though this novel approach can securely transmits the packets to a base station, the packets are forwarded along the constructed paths without checking the next hop node states. In this paper, we propose the next hop node selection method to cater this problem. Our proposed method evaluates the next hop node considering three factors (i.e., remaining energy level, number of shared keys, and number of filtered false packets). When the suitability criterion for next hop node selection is satisfied against a fix threshold value, the packet is forwarded to the next hop node. We aim to enhance energy efficiency and a detour of attacked areas to be effectively selected Experimental results demonstrate validity of the proposed method with up to 6% energy saving against the sinkhole attack as compared to the LEAP.

• Journal of Korea Multimedia Society
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• v.16 no.4
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• pp.464-471
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• 2013

With the advance of wireless sensor networks, WMSN(Wireless Multimedia Sensor Networks) researches to transfers multimedia data have been studied actively. First of all, three basic protocols, End-to-end, Hop-by-hop, and Unreliable transmission method, are compared to transfer multimedia data using simulations. This paper presents an efficient protocol to transfer multimedia data by overhearing messages of nodes and by transmitting next packets during the unused time interval. The proposed method is verified its performance by simulations and experiments. The results shows that the transmission rate of the proposed method 22% higher than that of End-to-end protocol with half of transmission time. Also the performance of the proposed method is compared with that of PIGAB(Packet Interval Gap based on Adaptive Backoff).

• Journal of Advanced Navigation Technology
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• v.11 no.3
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• pp.296-305
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• 2007

The HiLow, a hierarchical routing protocol for 6LoWPAN, needs smaller memory allocation and energy than other routing protocols. However, the HiLow has a weak point that does not provide the optimized routing path. In this paper, we propose the algorithm that can find the optimum next hop using neighboring nodes around the source node as well as hierarchical routing path information. We evaluate the performance of proposed algorithm using the computer simulation, and we can acquire results that decreases a number of hop count and transmitted message.

• Journal of Korea Multimedia Society
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• v.10 no.12
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• pp.1733-1740
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• 2007

In this paper, we propose a wireless location-based routing algorithm which uses the location information of its neighbor nodes and a destination node. At first, the proposed routing algorithm forwards a packet to the X direction by selecting a closest node to its destination as a next hop in terms of the X coordinate until the packet reaches closely to the packet's destination. Then the packet is forwarded to the Y direction by selecting a closest node to its destination in terms of the Y coordinate. We use a back off mechanism in case that a next hop cannot be found using the proposed routing algorithm, which resolves loops while forwarding. The experimental results show that the proposed routing algorithm performs well like the existing routing algorithms Ad hoc On-demand Distance Vector and Greedy Perimeter Stateless Routing. It is expected to use the proposed routing algorithm in the digital battlefield of military environments and survival games of commercial environments.

• Proceedings of the Korea Multimedia Society Conference
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• 2012.05a
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• pp.190-192
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• 2012

Vehicular Ad hoc Networks (VANETs) is the new wireless networking concept of mobile ad hoc networks in research community. Routing in vehicular is a major challenge and research area. The majority of current routing algorithms for VANETs utilize indirect metrics to select the next hop and produce optimal node path. In this paper, we propose a distance and angle based routing algorithm for VANETs, which combines a distance approach with an angle based geographical strategy for selecting the next hop, with the purpose of using direct metrics to build a optimal node route. The proposed algorithm has better performance than the previous scheme.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1366-1369
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• 2009

GPSR은 차량간 ad hoc 네트워크에서 위치기반 라우팅을 위하여 개발된 알고리즘이다. GPSR에서의 라우팅은 Greedy Forwarding을 사용하지만 차량 밀도가 높은 VANET환경에서는 한계가 있다. 이러한 한계를 극복하기 위하여 본 논문에서는 새로운 프로토콜을 제안하였다. 본 논문에 제시된 기법은 밀도가 높은 환경과 밀도가 낮은 환경에서의 가중치를 설정하여 current node, next-hop node 그리고 destination node 간의 관계를 반영한 값들을 구하고 그 중에서 최소치 값을 가지는 next-hop을 선택한다. 특히 가중치를 기반으로 하면 차량이 밀집되거나 희박한 환경하에서 GPSR 보다 더 최적화된 경로를 찾아낸다. 성능평가는 수학적 모델과 네트워크 시뮬레이터인 NS를 이용하여 본 모델에 기반한 고속도로 시뮬레이션을 진행하였다. 결과적으로 볼 때, 본 논문에 제시된 기법은 시간 지연 측면에서 GPSR보다 나은 결과를 보여 주었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.731-763
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• 2017

In Underwater Linear Sensor Networks (UW-LSN) routing process, nodes without proper address make it difficult to determine relative sensor details specially the position of the node. In addition, it effects to determine the exact leakage position with minimized delay for long range underwater pipeline monitoring. Several studies have been made to overcome the mentioned issues. However, little attention has been given to minimize communication delay using dynamic addressing schemes. This paper presents the novel solution called Hop-by-Hop Dynamic Addressing based Routing Protocol for Pipeline Monitoring (H2-DARP-PM) to deal with nodes addressing and communication delay. H2-DARP-PM assigns a dynamic hop address to every participating node in an efficient manner. Dynamic addressing mechanism employed by H2-DARP-PM differentiates the heterogeneous types of sensor nodes thereby helping to control the traffic flows between the nodes. The proposed dynamic addressing mechanism provides support in the selection of an appropriate next hop neighbour. Simulation results and analytical model illustrate that H2-DARP-PM addressing support distribution of topology into different ranges of heterogeneous sensors and sinks to mitigate the higher delay issue. One of the distinguishing characteristics of H2-DARP-PM has the capability to operate with a fewer number of sensor nodes deployed for long-range underwater pipeline monitoring.

• 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.