• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.580-581
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• 2018

In order to reduce end-to-end delay in EH-WSN (energy harvestin wireless sensor netowk), medium access control protocols using multi-hop routing technique have been studied. In a real environment, there are many situations where it is difficult to harvest enough energy than the energy consumed. Therefore, it is required to design a MAC protocol that allows nodes to reliably relay data without exhausting power in multi-hop transmission. In this paper, we propose a power-efficient MAC protocol that can select the relay node according to the residual power and the energy collection rate to increase network lifetime.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.125-129
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• 2015

The most important factor within the wireless sensor network is to have effective network usage and increase the lifetime of the individual nodes in order to operate the wireless network more efficiently. Therefore, many routing protocols have been developed. The LEACH protocol presented by Wendi Heinzelman, especially well known as a simple and efficient clustering based routing protocol. However, because LEACH protocol in an irregular network is the total data throughput efficiency dropped, the stability of the cluster is declined. Therefore, to increase the stability of the cluster head, in this paper, it proposes a stochastic cluster head selection method for improving the LEACH protocol. To this end, it proposes a SH-LEACH(Stochastic Cluster Head Selection Method-LEACH) that it is combined to the HEED and LEACH protocol and the proposed algorithm is verified through the simulation.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.139-146
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• 2007

Mobile Sensor Network(MSN) is actively studied due to the advent of mobile sensors such as Robomote and Robotic Sensor Agents(RSAs), However, existing studies on MSN have mainly focused on coverage hole problem which occurs in Stationary Sensor Network(SSN). To address coverage hole problem, these studies make mobile sensors move temporarily so that they do not make the best use of the mobility of mobile sensors, Thus, a mechanism utilizing the continuous movement of mobile sensors is proposed to improve the network coverage performance. However, this mechanism is presently immature and does not explain how to make routing path and send data from mobile sensors to a sink node, Therefore, to efficiently make routing path and send data from mobile sensors to a sink node, we propose a communication protocol for mobile sensor network where mobile sensors continuously move. The proposed protocol deploys not only mobile sensors but also stationary sensors which send sensing data to a sink node instead of mobile sensors. Simulation results show that the proposed protocol improves the performance in terms of network coverage and traffic overhead, compared to conventional SSN protocols.

• The Journal of the Korea Contents Association
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• v.12 no.4
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• pp.60-68
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• 2012

In recent years, the requirements on the high quality environment monitoring by using the sensor nodes which can handle the multimedia data in WSN have been increased. However, because the volume of multimedia data is tremendous, the limited bandwidth of a wireless channel may incur the bottleneck of a system. To solve such a problem, most of the existing distributed multi-path routing protocols based on multimedia data just focused on overcoming the limited bandwidth in order to enhance the energy efficiency and the transmission rate. However, because the existing methods can not apply a key-based technique to encrypt the multimedia data, they are very weak for the security. In this paper, we propose a secure disjointed multipath routing scheme for multimedia data transmission. Since our proposed scheme divides multimedia data(eg. image) into pixels and sends them through disjointed multipath routing, it can provide security to the whole network without using the key-based method. Our experimental results show that our proposed scheme reduces about 10% the amount of the energy consumption and about 65% the amount of the missed data packets caused by malicious nodes over the existing methods on average.

• Journal of the Korea Society of Computer and Information
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• v.18 no.6
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• pp.29-36
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• 2013

In wireless sensor networks, energy is the most important consideration because the lifetime of the sensor node is limited by battery. Most of the existing energy efficient routing protocols use the minimum energy path to minimize energy consumption, which causes an unbalanced distribution of residual energy among nodes. As a result, the power of nodes on energy efficient paths is quickly depletes resulting in inactive. To solve these problems, a method to equalize the energy consumption of the nodes has been proposed, but do not consider the link error rate in the wireless environment. In this paper, we propose a uniform energy consumption of cluster-based multi-hop routing mechanism considering the residual energy and the link error rate. This mechanism reduces energy consumption caused by unnecessary retransmissions and distributes traffic evenly over the network because considering the link error rate. The simulation results compared to other mechanisms, the proposed mechanism is energy-efficient by reducing the number of retransmissions and activation time of all nodes involved in the network has been extended by using the energy balanced path.

• Convergence Security Journal
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• v.9 no.2
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• pp.71-78
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• 2009

It is very difficult to apply previous security protocols to WSNs(Wireless Sensor Networks) directly because WNSs have resource constrained characteristics such as a low computing ability, power, and a low communication band width. In order to overcome the problem, we proposes a secure group communication scheme applicable to WSNs. The proposed scheme is a combined form of the TEEN(Threshold sensitive Energy Efficient sensor Network protocol) clustering based hierarchical routing protocol and security mechanism, and we assume that WSNs are composed of sensor nodes, cluster headers, and base stations. We use both private key and public key cryptographic algorithms to achieve an enhanced security and an efficient key management. In addition, communications among sensor nodes, cluster headers, and base stations are accomplished by a hierarchical tree architecture to reduce power consumption. Therefore, the proposed scheme in this paper is well suited for WSNs since our design can provide not only a more enhanced security but also a lower power consumption in communications.

• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.10-17
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• 2010

Sensor nodes used in Geosensor network are resource limited and power constrained. So it is necessary to research on routing protocols to gather data by using energy efficiently. Wireless sensor networks collect data gathered from sensor nodes by transfering it to the sink using multihop. However, it has two problems. First, the existing works require unnecessary data transmission for choosing a proper parent node to transfer data. Secondly, they have a large number of data transmission because each sensor node has a different path. To solves the problems, we, in this paper, propose a designated path based data aggregation scheme for efficient energy management in WSNs. The proposed scheme can reduce unnecessary data transmission by pre-determining a set of paths and can enable all the sensor nodes to participate in gathering data by running them in round-robin fashion. We show from performance analysis that the proposed scheme is more energy efficient than the existing directed diffusion(DD) and the hierarchical data aggregation(HDA).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.144-153
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• 2010

Flooding based routing protocols are usually used to disseminate information in wireless sensor networks. Those approaches, however, require message retransmissions to all nodes and induce huge collision rate and high energy consumption. In this paper, HoGoP (Hop based Gossiping Protocol) in which all nodes consider the number of hops from sink node to them, and decide own gossiping probabilities, is introduced. A node can decide its gossiping probability according to the required average reception percentage and the number of parent nodes which is counted with the difference between its hop and neighbors' ones. Therefore the decision of gossiping probability for network topology is adaptive and this approach achieves higher message reception percentage with low message retransmission than the flooding scheme. Through simulation, we compare the proposed protocol with some previous ones and evaluate its performance in terms of average reception percentage, average forwarding percentage, and forwarding efficiency. In addition, average reception percentage is analyzed according to the application requirement.

• Journal of Information Processing Systems
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• v.12 no.2
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• pp.275-294
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• 2016

A primary task in wireless sensor networks (WSNs) is data collection. The main objective of this task is to collect sensor readings from sensor fields at predetermined sinks using routing protocols without conducting network processing at intermediate nodes, which have been proved as being inefficient in many research studies using a static sink. The major drawback is that sensor nodes near a data sink are prone to dissipate more energy power than those far away due to their role as relay nodes. Recently, novel WSN architectures based on mobile sinks and mobile relay nodes, which are able to move inside the region of a deployed WSN, which has been developed in most research works related to mobile WSN mainly exploit mobility to reduce and balance energy consumption to enhance communication reliability among sensor nodes. Our main purpose in this paper is to propose a solution to the problem of deploying mobile data collectors for alleviating the high traffic load and resulting bottleneck in a sink's vicinity, which are caused by static approaches. For this reason, several WSNs based on mobile elements have been proposed. We studied two key issues in WSN mobility: the impact of the mobile element (sink or relay nodes) and the impact of the mobility model on WSN based on its performance expressed in terms of energy efficiency and reliability. We conducted an extensive set of simulation experiments. The results obtained reveal that the collection approach based on relay nodes and the mobility model based on stochastic perform better.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.839-842
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• 2011

Lately Various researches on energy harvesting techniques for wireless sensor networks have been performed to overcome the power limitation of sensor nodes. In wireless sensor networks with harvesting techniques, sensor nodes exploit environmental energy, such as solar or wind energy, as the power sources of the nodes. Existing energy constrained environment routing protocols may not be suitable for energy harvesting based wireless sensor networks because they do not consider the accumulated energy from harvesting devices. In addition, the paths which aren't dispersed shorten the network lifetime. Therefore, in this paper, the algorithm that the path between each node is dispersed is proposed. In case of using the algorithm to be proposed through the simulator it showed that path of the node is variously reflected.