• Convergence Security Journal
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• v.20 no.5
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• pp.33-39
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• 2020

In MANET consisting of only mobile nodes, all nodes serve as routes. However, the dynamic topology due to frequent movement of nodes degrades routing performance and is also cause of many security vulnerabilities. Therefore, security must be applied to routing techniques that can influence the performance of MANET. In this paper, we propose a technique for efficiently responding to various routing attacks and safe data transmission through application of zone-key based security routing techniques. A zone-based network structure was used, and a management node that manages member nodes in each zone was used in the proposed technique. In addition, the damage from the attacking node was minimized by issuing a key to each node and applying this to a routing technique. The zone management node issues a key for encryption routing information and manages the issuance information. A member node that wants to transmit data encrypts routing in formation using a key issued from the zone management node, and then performs path discovery using this. The improved performance of the proposed technique was confirmed through a comparative experiment with the CBSR and ARNA technique, excellent performance was confirmed through experiments.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.539-542
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• 2011

VANET(Vehicular Ad-hoc Network)은 차량 간의 무선통신(Vehicule to Vehicule: V2V) 또는 차량과 RSE(Road Side Equipment)간의 무선통신(Vehicule to Infrastructure: V2I)을 이용하는 기술이다. 사용자들은 VANET을 통하여 실시간 도로 상황, 응급 상황 등을 파악할 수 있으며 도로 혼잡 등을 줄일 수 있다. 본 논문에서는 VANET 기반 서비스 중 응급상황 알림 서비스에서 발생할 수 있는 Broadcast Storm 문제를 해결하는 라우팅 알고리즘들의 작동 원리와 문제점을 분석한다.

• Journal of KIISE:Information Networking
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• v.35 no.5
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• pp.409-414
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• 2008

In mobile ad hoc networks, most of on demand routing protocols such as DSR and AODV do not deal with traffic load during the route discovery procedure. To solve the congestion and achieve load balancing, many protocols have been proposed. However, the existing load balancing schemes has only considered avoiding the congested route in the route discovery procedure or finding an alternative route path during a communication session. To mitigate this problem, we have proposed a new scheme which considers the packet bursting mechanism in congested nodes. The proposed packet bursting scheme, which is originally introduced in IEEE 802.11e QoS specification, is to transmit multiple packets right after channel acquisition. Thus, congested nodes can forward buffered packets promptly and minimize bottleneck situation. Each node begins to transmit packets in normal mode whenever its congested status is dissolved. We also propose two threshold values to define exact overloaded status adaptively; one is interface queue length and the other is buffer occupancy time. Through an experimental simulation study, we have compared and contrasted our protocol with normal on demand routing protocols and showed that the proposed scheme is more efficient and effective especially when network traffic is heavily loaded.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.5
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• pp.28-37
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• 2007

IEEE 1451 standard defines an interface for network and transducer. In this paper, We propose an architectural model to configure data acquisition system and wireless smart sensor node based on IEEE 1451 standard. Proposed Network Capable Application Processor(NCAP) supports the task of data acquisition and communication for smart sensor node and network. The NCAP is able to reconfigure without interrupting the functionality of the wireless sensor node and receives the critical information of transducer using the DB. Smart sensor node is able to provide the basic information of sensor in digital format. This digital format is called Transducer Electronic Data Sheet(TEDS), is capable of plug-and-play capability of wireless sensor node and the NCAP. We simplify the format of TEDS and template to apply to wireless network environment. information of TEDS and template is transmitted using ad-hoc routing. This study system uses body temperature sensor and ECG(Electrocardiogram) sensor to provide the medical information service. The format of template is selected by data sheet of the sensor and reconfigured to accurately describe the property of the sensor. DB of NCAP is possible to register new template and information of the property as developing new sensor.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.16-27
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• 2014

In this paper, we propose an efficient grid based routing scheme using the location information in order to reduce the routing cost in mobile ad-hoc networks. In our proposed scheme, all nodes can be a candidate to forward messages to the specified destination node and reduce the management cost of head nodes because they do not exist. The intermediate nodes determine the next hop relaying messages on the basis of location relations between a node and a grid zone. The proposed scheme explores the routing path considering the direction of a node using the coordinate of a grid zone and neighbor node information. It also maintains the routing path considering connectivities among the nodes. In order to show the superiority of the proposed routing scheme, we compare it with the existing grid based routing scheme in terms of the overhead of message, the success rate of transmission.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.2002-2019
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• 2017

RPL routing protocol for low-power and lossy networks is an Internet Engineering Task Force (IETF) recommended IPv6 based protocol for routing over Low power Lossy Networks (LLNs). RPL is proposed for networks with characteristics like small packet size, low bandwidth, low data rate, lossy wireless links and low power. RPL is a proactive routing protocol that creates a Directed Acyclic Graph (DAG) of the network topology. RPL is increasingly used for Internet of Things (IoT) which comprises of heterogeneous networks and applications. RPL proposes a single path routing strategy. The forwarding technique of RPL does not support multiple paths between source and destination. Multipath routing is an important strategy used in both sensor and ad-hoc network for performance enhancement. Multipath routing is also used to achieve multi-fold objectives including higher reliability, increase in throughput, fault tolerance, congestion mitigation and hole avoidance. In this paper, M-RPL (Multi-path extension of RPL) is proposed, which aims to provide temporary multiple paths during congestion over a single routing path. Congestion is primarily detected using buffer size and packet delivery ratio at forwarding nodes. Congestion is mitigated by creating partially disjoint multiple paths and by avoiding forwarding of packets through the congested node. Detailed simulation analysis of M-RPL against RPL in both grid and random topologies shows that M-RPL successfully mitigates congestion and it enhances overall network throughput.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.3
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• pp.83-89
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• 2010

Scalable routing is one of the key challenges in designing and operating large scale MANETs. Performance of routing protocols proposed so far is only guaranteed under various limitation, i.e., dependent of the number of nodes in the network or needs the location information of destination node. Due to the dependency to the number of nodes in the network, as the number of nodes increases the performance of previous routing protocols degrade dramatically. We propose Cluster Overlay Dynamic Source Routing (CODSR) protocol. We conduct performance analysis by means of computer simulation under various conditions - diameter scaling and density scaling. Developed algorithm outperforms the DSR algorithm, e.g., more than 90% improvement as for the normalized routing load. Operation of CODSR is very simple and we show that the message and time complexity of CODSR is independent of the number of nodes in the network which makes CODSR highly scalable.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.58-65
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• 2008

This paper presents a new geographic distributed hash table (GDHT) for MANETs or Mesh networks, where virtual geographic protocol is used. In previous wort GDHT is applied to a network scenario based on two dimensional Cartesian coordinate system. Further, logical data space is supposed to be uniformly distributed. However, mobile node distribution in a network using virtual geographic routing is not matched to data distribution in GDHT. Therefore, if we apply previous GDHT to a virtual geographic routing network, lots of DHT data are probably located at boundary nodes of the network or specific nodes, resulting in long average-delay to discover resource (or service). Additionally, in BVR(Beacon Vector Routing) or LCR(Logical Coordinate Routing), because there is correlation between coordinate elements, we cannot use normal hash function. For this reason, we propose to use "geographic hash function" for GDHT that matches data distribution to node distribution and considers correlation between coordinate elements. We also show that the proposed scheme improves resource discovery efficiently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3A
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• pp.219-224
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• 2008

In the c-DSDV routing protocol proposed to improve the scalability of DSDV, clusterheads manage a routing table that has only clusterheads as potential destinations and flood update request message to its neighbor clusterheads periodically or at the time of topology change. Accordingly, the convergence range of topology change by a single update request message was expanded nine times as wide as that of DSDV, increasing routing correctness; however, c-DSDV suffers from the congestion of clusterheads since data packets always go through clusterheads of the clusters on the routing path. To improve this problem, we propose an adaptive routing scheme that judges if detouring clusterhead is possible on the fly while packets are forwarded. As a result, a routing path length is shortened and an end-to-end delay is improved by the reduced queue length. It shows that the end-to-end delay is reduced by almost 40% through simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.4244-4274
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• 2021

The utilization of UAVs in various fields has led to the development of flying ad hoc network (FANET) technology. In a network environment with highly dynamic topology and frequent link changes, the traditional routing technology of FANET cannot satisfy the new communication demands. Traditional routing algorithm, based on geographic location, can "fall" into a routing hole. In view of this problem, we propose a geolocation routing protocol based on multi-agent reinforcement learning, which decreases the packet loss rate and routing cost of the routing protocol. The protocol views each node as an intelligent agent and evaluates the value of its neighbor nodes through the local information. In the value function, nodes consider information such as link quality, residual energy and queue length, which reduces the possibility of a routing hole. The protocol uses global rewards to enable individual nodes to collaborate in transmitting data. The performance of the protocol is experimentally analyzed for UAVs under extreme conditions such as topology changes and energy constraints. Simulation results show that our proposed QLGR-S protocol has advantages in performance parameters such as throughput, end-to-end delay, and energy consumption compared with the traditional GPSR protocol. QLGR-S provides more reliable connectivity for UAV networking technology, safeguards the communication requirements between UAVs, and further promotes the development of UAV technology.