• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1390-1398
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• 2010

We present the concept of applying Wireless Mesh Networking (WMN) technology into Smart Grid, which is recently rising as a potential technology in various areas thanks to its advantages such as low installation costs, high scalability, and high flexibility. Smart Grid is an intelligent, next-generation electrical power network that can maximize energy efficiency by monitoring utility information in real-time and controlling the flow of electricity with IT communications technology converged to the existing power grid. WMNs must be designed for Smart Grid communication systems considering not only the high level of reliability, QoS support and mass-data treatment but also the properties of the traditional power grid. In addition, it is essential to design techniques based on international standards to support interoperability and scalability. In this paper, we evaluate the performance of IEEE 802.11s based Smart Grid Mesh Networks by conducting preliminary simulation studies with the ns-3 simulator. We also outline some challenging issues that should be reviewed when considering WMNs as the candidate for Smart Grid communication infrastructure.

• Journal of KIISE:Information Networking
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• v.36 no.5
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• pp.456-469
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• 2009

We develop a new wireless link quality metric, ECOT(Estimated Channel Occupancy Time) that enables a high throughput route setup in wireless mesh networks. The key feature of ECOT is to be applicable to diverse mesh network environments where IEEE 802.11 MAC (Medium Access Control) variants are used. We take into account the exact operational features of 802.11 MAC protocols, such as 802.11 DCF(Distributed Coordination Function), 802.11e EDCA(Enhanced Distributed Channel Access) with BACK (Block Acknowledgement), and 802.11n A-MPDU(Aggregate MAC Protocol Data Unit), and derive the integrated link metric based on which a high throughput end-to-end path is established. Through extensive simulation in random-topology settings, we evaluate the performance of proposed link metric and present that ECOT shows 8.5 to 354.4% throughput gain over existing link metrics.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.24 no.12 s.211
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• pp.107-114
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• 2006

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.53-59
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• 2009

As a special type of Wireless Ad Hoc Networks, Wireless Mesh Networks (WMNs) have become the comer stone of research issues. Due to the limited operational environment of WMNs, an efficient connected dominating set (CDS) construction scheme is an important concern since it has been found extremely useful in broadcasting, routing and virtual backbone construction. In this paper, we propose a distributed Bandwidth-Interference aware CDS construction scheme to improve the network performance via two parameters such as node's number of neighbor and link bandwidth. Our CDS construction scheme selects the node that has more neighbors and enough bandwidth to support more end-devices in order to enhance overall network throughput and reliability. We confirm through simulations and show that our scheme constructs the CDS with the small subset of DS and the link that has better bandwidth.

• Journal of KIISE
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• v.41 no.10
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• pp.810-823
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• 2014

The wireless mesh network based on IEEE 802.11s provides a routing based on a destination address as it inherits legacy internet architecture. However, this architecture interested in not 'what' which is originally the users goal but 'where'. Futhermore, because of the rapid increase of the number of mobile devices recently, the mobile traffic increases geometrically. It reduces the network effectiveness as increasing many packets which have same payload in the situation of many users access to the same contents. In this paper, we propose an OpenFlow-based contents routing for the wireless mesh network(WMN) to solve this problem. We implement contents layer to the legacy network layer which mesh network uses and the routing technique based on contents identifier for efficient contents routing. In addition we provide flexibility as we use OpenFlow. By using this, we implement caching technique to improve effectiveness of network as decreasing the packet which has same payload in WSN. We measure the network usage to compare the flooding technique, we measure the delay to compare environment using caching and non caching. As a result of delay measure it shows 20% of performance improve, and controller message decrease maximum 89%.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.87-93
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• 2009

Wireless mesh networks (WMNs) are emerging technologies that provide ubiquitous environments and wireless broadband access. The aggregate capacity of WMNs can be improved by minimizing the effect of channel interference. The IEEE 802.11b/g standard which is mainly used for the network interface technology in WMNs provides 3 multiple channels. We must consider the channel scanning delay and the channel dependency problem to effectively assign channels in like these multi-channel WMNs. This paper proposes a cluster-based channel assignment (CB-CA) algorithm for multi-channel WMNs to solve such problems. The CB-CA does not perform the channel scanning and the channel switching through assigning co-channel to the inter-cluster head (CH) links. In the CB-CA, the communication between the CH and cluster member (CM) nodes uses a channel has no effect on channels being used by the inter-CH links. Therefore, the CB-CA can minimize the interference within multi-channel environments. Our simulation results show that CB-CA can improve the performance of WMNs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1050-1057
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• 2008

Wireless Mesh Networks (WMNs) have recently become a hot issue to support high link capacity in wireless access networks. The IEEE 802. I 1 standard which is mainly used for the network interface technology in WMNs supports up to 3 or 12 multiple channels according to the IEEE 802.11 specification. However, two important problems must be addressed when we design a channel assigmnent algorithm: channel dependency problem and channel scanning delay. The former occurs when the dynamic channel switching of an interface leads to the channel switching of other interfaces to maintain node connectivity. The latter happens per channel switching of the interface, and affects the network performance. Therefore, in this paper, we propose the Distance-Based Channel Assigmnent (DB-CA) scheme for multi-channel WMNs to solve such problems. In DB-CA, nodes just perform channel switching without channel scanning to communicate with neighboring nodes that operate on different channels. Furthermore, DB-CA minimizes the interference of channels being used by nodes near the gateway in WMNs. Our simulation results show that DB-CA achieves improved performance in WMNs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1883-1890
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• 2009

Existing MAC protocol can not show good performance in WMN environment. New MAC protocols is proposed because of Mobile Point's mobility, entire distributed environment, heavy traffic problems. This thesis proposes new channel contention method fur Mesh DCF. Mesh DCF uses ACH phase in TDMA frame to perform selection and elimination. Prioritized phases's count m and Fair Elimination phases's count n is determine contention level and make string probability to only one win the contention. Contention Number group's count K to determine the contention level in Fair Elimination Phase gives Fairness but make low probability to only one win the contention. It is sure that enough size of n and K can improve entire performance as result.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11A
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• pp.912-923
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• 2011

In this paper, we propose a routing protocol for WMNs to provide passengers in public transportation vehicles (e.g., bus and tram) with Internet access service. In order to support end users with a reliable Internet connection despite the mobility of vehicles, we assume that mesh router, called mobile mesh router (MMR), is installed in a vehicle and manages a route to Internet Gateway (IGW). We therefore propose an efficient routing protocol and its routing metric, called ETT-TR, considering trajectory information of vehicle as well as link quality in order to find a route between them. Using NS-2 simulations, we observe that our proposed routing protocol reduces the end-to-end delay and improves throughput performance.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.3
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• pp.322-331
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• 2013

Wireless Mesh Networks(WMNs) is generally composed of radio nodes in the mesh topology. WMNs consists of mesh client, mesh router and gateway connected to a wired network. Each client and router relay messages to the gateway for communication. WMNs is widely used recently in many areas can provide extended coverage based on multi-hop communication and ubiquitous communication at any time and any location. However the competition and collision between each node to transmit data is inevitable when the same channel is used for transmission. The transmission opportunities and the throughput of nodes located far from gateway decrease more if the communication channel is accessed based on competitive CSMA/CA scheme using DCF(Distributed Coordination Function) provided by IEEE 802.11 MAC. In this paper, we improve the performance of the TCP fairness and throughput of the nodes with more than 2 hops by applying various algorithms for controlling contention window values. Also, we evaluate the performance using ns-2 simulator, According to the results, proposed scheme can enhance the fairness characteristic of each node irrespective of data to the gateway.