• Journal of Korea Multimedia Society
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• v.25 no.11
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• pp.1564-1571
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• 2022

Wireless sensor network(WSN) is being used in various fields such as reconnaissance, echelon scale identification, weather observation, etc. using small sensors in an environment without a network infrastructure environment. In addition, WSN uses limited battery power, so study on routing protocols to extend the lifetime of the network is important. PEGASIS, a hierarchical routing protocol, accounts for the majority of energy-efficient routing protocol studies and is well known as a representative protocol. In this study, based on PEGASIS, we propose a protocol that constructs multiple chains rather than one chain using the AoA of nodes. The proposed protocol has the advantage of reducing the transmission distance of nodes and eliminating unnecessary transmissions, thereby increasing energy efficiency compared to the existing protocols.

• Convergence Security Journal
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• v.7 no.3
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• pp.71-78
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• 2007

We proposed a simple and efficient routing protocol designed specifically for multi-hop ad-hoc networks. The proposed protocol is composed of the two routing tables which work together to allow nodes to send and receive packets. All aspects of the protocol can be operated on networks entirely consisting bidirectional links and networks with unidirectional links. Finding unidirectional link is embedded in the routing protocol since we considered not only bidirectional links but also unidirectional links when we developed a routing method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.103-110
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• 2008

When there is uncertainty in topological rate of change, motility model and terrain condition, the performance severely degrades in MANET. The concept of transition of routing protocol on the fly according to the network parameters such as coverage, connectivity and mobility etc. may counterbalance the problems stated above. The mathematical modeling of feedback parameters has been derived, and the architecture for the multi-routing protocol system providing an adaptation from one routing protocol to another is also investigated. This paper is extensively devoted on the analysis of mobility, connectivity and their effects on the network and finally transition into another routing protocol according to them.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.173-179
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• 2008

An ad hoc network is multi-hop wireledss formed by mobile node without infrastructure. Due to the mobility of nodes in mobile ad hoc networks, the topology of network changes frequently. In this environments, multicast protocols are faced with the challenge of producing multi-hop routes and limitation of bandwidth. We compare the performance of two multicast routing protocols for mobile ad hoc networks - Serial Multiple Disjoint Tree Multicast Routing Protocol (Serial MDTMR) and Adaptive Core Multicast Routing Protocol (ACMRP). The simulator is implemented with GloMoSim.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3860-3875
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• 2014

Cognitive radio networks (CRNs) are composed of mobile users who can use multiple spectrum bands for communication. CRNs allow unlicensed users (called cognitive users) to efficiently utilize unused licensed spectrums without interfering with communications of licensed users (called primary users). The main goals of CRNs are to mitigate spectrum saturation and to improve spectrum utilization. This paper introduces state-of-the-art routing protocols for CRNs and addresses some limitations of these protocols. To resolve the limitations, we suggest a new research direction for routing protocols in CRNs. We implement our protocol to compare with the existing routing protocols for multi-hop CRNs. Our protocol shows good performance compared to the existing routing protocols in terms of network performance and PU protection.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11A
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• pp.1021-1033
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• 2008

In recent years, the growing interest in wireless sensor network has resulted in thousands of publications. Most of this research is concerned with delivering raw data such as temperature, pressure, or humidity. Recently, the focus of sensor network paradigm is changing for delivering multimedia contents. However, most existing routing protocols are not very practical for transmitting multimedia contents in resource constrained sensor networks. In this paper, we propose an optimized node-disjoint multi-path routing protocol for throughput enhancement and load balancing. We focused on how to allocate traffic to independent multiple end-to-end routes. Decentralized transmission using our node-disjoint multi-path routing scheme results in bandwidth aggregation and throughput enhancement. In addition, our scheme provides ways to remove link-joint routes for decreasing routing overhead.

• 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.

• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.149-156
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• 2011

In wireless multi-hop network, many applications need multicast communication where the group leader needs to send data to all members of the group. Multicast routing provides a balanced, efficient, and fairness network environment for the group members. However, large load for transmission management to leader node and signal interference between several paths for multi-hop links always took long transmission delay and low throughput efficiency. In this paper, we propose a Zone-based Hierarchical Multicast Routing Protocol (ZHMP). This routing protocol is designed based on zone routing schemes, where proactive routing is applied for intra-zone node level multicasting and reactive routing is used for searching inter-zone paths. By each hierarchical and independent multicast working in separated zones, load of multicast source node will be distributed by several zone-level routings for a better load balance and signal interference between each multi-hop paths will be resisted for a maximum multicast throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2C
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• pp.188-195
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• 2012

Many systems are developing for the realization of NCW(Network Centric Warfare). UAV(Unmanned Aerial Vehicle) Network is attracting attention in a lot of military applications. In general, UAVs have the potential to create an ad-hoc network and greatly reduce the hops from source to destination. However, UAV networks exhibit unique properties such as high mobility, high data rate, and real time service. The routing protocols are required to design the multi-hop routing protocols that can dynamically adapt to the requirements of UAV network. In this paper we analyse Geographic Routing Protocol is based on geographical distance between source and destination for efficient and reliable transmission. Geographic Routing Protocol is evaluated in video service scenarios with TDMA model in our simulation. The simulation results show that the performance of Geographic Routing Protocol is better than the MANET Routing Protocol in terms of packet received ratio, end to end delay, and routing traffic sent.

• Journal of Communications and Networks
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• v.10 no.4
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• pp.455-464
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• 2008

To provide network services consistently under various network failures, enterprise networks increasingly utilize path diversity through multi-homing. As a result, multi-homed non-transit autonomous systems become to surpass single-homed networks in number. In this paper, we address an inevitable problem that occurs when networks with multiple entry points deploy firewalls in their borders. The majority of today's firewalls use stateful inspection that exploits connection state for fine-grained control. However, stateful inspection has a topological restriction such that outgoing and incoming traffic of a connection should pass through a single firewall to execute desired packet filtering operation. Multi-homed networking environments suffer from this restriction and BGP policies provide only coarse control over communication paths. Due to these features and the characteristics of datagram routing, there exists a real possibility of asymmetric routing. This mismatch between the exit and entry firewalls for a connection causes connection establishment failures. In this paper, we formulate this phenomenon into a state-sharing problem among multiple fire walls under asymmetric routing condition. To solve this problem, we propose a stateful inspection protocol that requires very low processing and messaging overhead. Our protocol consists of the following two phases: 1) Generation of a TCP SYN cookie marked with the firewall identification number upon a SYN packet arrival, and 2) state sharing triggered by a SYN/ACK packet arrival in the absence of the trail of its initial SYN packet. We demonstrate that our protocol is scalable, robust, and simple enough to be deployed for high speed networks. It also transparently works under any client-server configurations. Last but not least, we present experimental results through a prototype implementation.