• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.572-580
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• 2010

The Wireless Mesh Network uses a wireless communication technology with transmission rates simular to a cable which is used as a backbone networks. The topology structure is in a Mesh form which resembles an Ad-hoc networks. However, a metric is needed in order to set the channel access control method to operate intentions and interior motions are different. In this document, an efficient channel for delivering datas to improve access controls to a wireless mesh networks. The improved performance of the proposed plan is for a hidden and exposed mesh client through an exclusive channels to perform a proposed and analyzed methods.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.124-126
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• 2006

Mobile Ad hoc networking is an emerging technology and in these days many applications are being developed to run on these networks. In these networks lookup services are very important because all nodes do not have same resources in term of memory and computing power. Nodes need to use different services offered by different servers. Reliable and efficient scheme should be available for lookup services due to limited bandwidth and low computing power of devices in mobile ad hoc networks. Due to mobility and rapid change in network topology, lookup mechanism used in wired network is not appropriate. Service discovery mechanism can be divided into two main categories Centralized and Distributed. Centralized mechanism is not reliable as there is no central node in these networks. Secondly centralized mechanism leads toward single point failure. We can handle the service discovery mechanism by distributing server's information to each node. But this approach is also not appropriate due to limited bandwidth and rapid change in network. In this paper, we present reliable lookup service scheme which is based on distributed mechanism. We are not using replication approach as well due to low bandwidth of wireless networks. In this scheme service discovery mechanism will be handled through different lookup servers. Reliability is the key feature of our proposed scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3512-3528
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• 2016

A network with high mobility nodes or vehicles is vehicular ad hoc Network (VANET). For improvement in communication efficiency of VANET, many techniques have been proposed; one of these techniques is vehicular node clustering. Cluster nodes (CNs) and Cluster Heads (CHs) are elected or selected in the process of clustering. The longer the lifetime of clusters and the lesser the number of CHs attributes to efficient networking in VANETs. In this paper, a novel Clustering algorithm is proposed based on Ant Colony Optimization (ACO) for VANET named ACONET. This algorithm forms optimized clusters to offer robust communication for VANETs. For optimized clustering, parameters of transmission range, direction, speed of the nodes and load balance factor (LBF) are considered. The ACONET is compared empirically with state of the art methods, including Multi-Objective Particle Swarm Optimization (MOPSO) and Comprehensive Learning Particle Swarm Optimization (CLPSO) based clustering techniques. An extensive set of experiments is performed by varying the grid size of the network, the transmission range of nodes, and total number of nodes in network to evaluate the effectiveness of the algorithms in comparison. The results indicate that the ACONET has significantly outperformed the competitors.

• Journal of Korea Multimedia Society
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• v.21 no.8
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• pp.897-908
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• 2018

In this paper, we propose a security framework for a cluster drones network using the MAVLink (Micro Air Vehicle Link) application protocol based on FANET (Flying Ad-hoc Network), which is composed of ad-hoc networks with multiple drones for IoT services such as remote sensing or disaster monitoring. Here, the drones belonging to the cluster construct a FANET network acting as WTRP (Wireless Token Ring Protocol) MAC protocol. Under this network environment, we propose an efficient algorithm applying the Lightweight Encryption Algorithm (LEA) to the CTR (Counter) operation mode of WPA2 (WiFi Protected Access 2) to encrypt the transmitted data through the MAVLink application. And we study how to apply LEA based on CBC (Cipher Block Chaining) operation mode used in WPA2 for message security tag generation. In addition, a modified Diffie-Hellman key exchange method is approached to generate a new key used for encryption and security tag generation. The proposed method and similar methods are compared and analyzed in terms of efficiency.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.4
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• pp.243-253
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• 2010

Multihop data delivery in vehicular ad hoc networks (VANETs) suffers from the fact that vehicles are highly mobile and inter-vehicle links are frequently disconnected. In such networks, for efficient multihop routing of road safety information (e.g. road accident and emergency message) to the area of interest, reliable communication and fast delivery with minimum delay are mandatory. In this paper, we propose a multihop vehicle-to-infrastructure routing protocol named Vertex-Based Predictive Greedy Routing (VPGR), which predicts a sequence of valid vertices (or junctions) from a source vehicle to fixed infrastructure (or a roadside unit) in the area of interest and, then, forwards data to the fixed infrastructure through the sequence of vertices in urban environments. The well known predictive directional greedy routing mechanism is used for data forwarding phase in VPGR. The proposed VPGR leverages the geographic position, velocity, direction and acceleration of vehicles for both the calculation of a sequence of valid vertices and the predictive directional greedy routing. Simulation results show significant performance improvement compared to conventional routing protocols in terms of packet delivery ratio, end-to-end delay and routing overhead.

• Journal of Computing Science and Engineering
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• v.4 no.3
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• pp.225-239
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• 2010

This paper introduces a new approach to modeling relative distance among nodes under a variety of communication rates, due to node's mobility in Mobile Ad-hoc Networks (MANETs). When mobile nodes move to another location, the relative distance of communicating nodes will directly affect the data rate of transmission. The larger the distance between two communicating nodes is, the lower the rate that they can use for transferring data will be. The connection certainty of a link also changes because a node may move closer to or farther away out of the communication range of other nodes. Therefore, the stability of a route is related to connection entropy. Taking into account these issues, this paper proposes a new routing metric for MANETs. The new metric considers both link weight and route stability based on connection entropy. The problem of determining the best route is subsequently formulated as the minimization of an object function formed as a linear combination of the link weight and the connection uncertainty of that link. The simulation results show that the proposed routing metric improves end-to-end throughput and reduces the percentage of link breakages and route reparations.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.1
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• pp.14-19
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• 2009

In Mobile Ad-hoc Network, link failure and packet loss may occur frequently due to its nature of mobility and limited battery life. In this paper, an enhanced robust routing protocol based on AODV(Ad hoc On-demand Distance Vector routing) by monitoring variation of receiving signal strength is proposed. New metric function that consists of node mobility and hops of path is used for routing decision. For preventing route failure by node movement during data transmission, a new route maintenance is presented. If the node movement is detected, the routing agent switches local path to its neighbor node. Simulation results show that the performance of the proposed routing scheme is superior to previous AODV protocol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.1041-1047
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• 2010

One of the weaknesses of ad hoc network is that a route used between a source and a destination is to break during communication. To solve this problem, one approach consists of selecting routes whose nodes have the most stable link cost. In this paper proposes a new method for improving the low power distributed MAC. The method is rule-based on the context awareness of the each nodes energy in clustering. The proposed networks scheme could get better improve the awareness for data to achieve and performance on their clustering establishment and messages transmission.

• Journal of Information Technology Services
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• v.11 no.4
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• pp.195-213
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• 2012

In ubiquitous environments, the Intelligent Transportation System (ITS) protocol is a typical service used to improve the quality of life for humans. The Vehicular Ad-hoc Network (VANET) protocol, a part of ITS, needs further study with regards to its support for high reliability, high speed mobility, data transmission efficiency, and so on. The IEEE 802.11 standard provides a high data rate channel, but it was designed for peer-to-peer network protocols. IEEE 802.11p also provides a high data rate channel, however, it only facilitates communication between roadside and on-board equipment. A VANET has characteristics that enable its topology to change rapidly; it can also be expanded to a multi-hop range network during communication. Therefore, the VANET protocol needs a way to infer the current topology information relating to VANET equipped vehicles. In this paper, we present the Multi-Beacon MAC Protocol, and propose a method to resolve the problem of beacon collisions in VANET through the use of this Multi-Beacon MAC protocol. Evaluation of the performance of Multi-Beacon MAC protocol by means of both mathematical analyses and simulation experiments indicate that the proposed method can effectively reduce beacon collisions and improve the throughput and the delay between vehicles in VANET systems.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.837-844
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• 2019

In this paper, we propose the AMBM(: Adaptive Multi-channel Backoff Machisum) -Mac protocol to provide high throughput for non-safety applications in VANET(: Vehicular Ad Hoc Networks) environment. The proposed protocol guarantees the quality of service of non-safety packets by dynamically adjusting CW(: Channel Window) of WSA(: WAVE Service Advertisement) to maximize throughput between non-safety packets of different priority. It also shows that allocating a large amount of time for channel coordination and time slot reservation for SC and dynamically adjusting CW and CCI as nodes increase to reduces transmission delay than IEEE 1609.9, C-MAC(: Coordinated multi-channel MAC, and Q-VCI(: QoS Variable CCH Interval) protocols.