• 전기학회논문지
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• 제68권1호
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• pp.98-101
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• 2019

In this paper, we propose the power-based pipelined-forwarding MAC protocol which can select relay nodes according to the residual power and energy harvesting rate in EH-WSN (energy-harvesting wireless sensor networks). The proposed MAC follows a pipelined-forwarding scheme in which nodes repeatedly sleep and wake up in an EH-WSN environment and data is continuously transmitted from a high-level node to a low-level node. The sleep interval is adaptively controlled so that nodes with low energy harvesting rate can be charged sufficiently, thereby minimizing the transmission delay and increasing the network lifetime. Simulation shows that the proposed MAC protocol improves the balance of residual power and network lifetime.

• 한국통신학회논문지
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• 제33권4B호
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• pp.207-214
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• 2008

미래 인터넷 환경에서 무선 센서 네트워크(Wireless Sensor Networks)는 광범위한 응용에 적용될 중요한 기술이다. 그러나 센서 네트워크는 기존의 네트워크와는 달리 소형이고 제한된 배터리 에너지로 운용되어야 하기 때문에 센서 네트워크가 설치된 지역에서 오랜 시간동안 많은 정보를 얻기 위해서는 에너지 효율적인 프로토콜 개발이 필수적이다. 또 센서 네트워크는 무선 멀티 홉 (multi hop) 통신을 통해 정보가 전달되기 때문에 전송 지연이 발생한다. 이런 전송 지연은 센싱된 정보가 적시에 전달되어 적절한 조치가 이루어지는 것을 어렵게 하기 때문에 센서 네트워크의 프로토콜을 설계할 때 전송 지연이 발생하지 않도록 해야 한다. 본 논문은 무선 센서 네트워크에서 일정 시간의 전송지연을 유지하면서 각 노드의 에너지의 소비를 최소화하는 데이터 전달 프로토콜을 제안한다. 제안된 프로토콜은 wakeup 스케줄링과 MAC 프로토콜을 통합하여 동작하며, 데이터를 전달하는 동안 네트워크 전체의 에너지 소모를 균등하게 해 준다. 제안된 프로토콜은 모의실험을 통해서 기존의 프로토콜과 비교하여 성능을 검증하였다.

• Journal of Communications and Networks
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• 제16권4호
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• pp.465-474
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• 2014

Wireless sensor network (WSN) is considered to be one of the most important research fields for ubiquitous healthcare (u-healthcare) applications. Healthcare systems combined with WSNs have only been introduced by several pioneering researchers. However, most researchers collect physiological data from medical nodes located at static locations and transmit them within a limited communication range between a base station and the medical nodes. In these healthcare systems, the network link can be easily broken owing to the movement of the object nodes. To overcome this issue, in this study, the fast link exchange minimum cost forwarding (FLE-MCF) routing protocol is proposed. This protocol allows real-time multi-hop communication in a healthcare system based on WSN. The protocol is designed for a multi-hop sensor network to rapidly restore the network link when it is broken. The performance of the proposed FLE-MCF protocol is compared with that of a modified minimum cost forwarding (MMCF) protocol. The FLE-MCF protocol shows a good packet delivery rate from/to a fast moving object in a WSN. The designed wearable platform utilizes an adaptive linear prediction filter to reduce the motion artifacts in the original electrocardiogram (ECG) signal. Two filter algorithms used for baseline drift removal are evaluated to check whether real-time execution is possible on our wearable platform. The experiment results shows that the ECG signal filtered by adaptive linear prediction filter recovers from the distorted ECG signal efficiently.

• 디지털산업정보학회논문지
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• 제11권3호
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• pp.79-90
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• 2015

Multipath routing technique is recognized as one of the effective approaches to improve the reliability of data forwarding. However, the traditional multipath routing focuses only on how many paths are needed to ensure a desired reliability. For this purpose, the protocols construct additional paths and thus cause significant energy consumption. These problems have motivated the study for the energy-efficient and reliable data forwarding. Thus, this paper proposes an energy-efficient concurrent multipath routing protocol with a small number of paths based on interaction between paths. The interaction between paths helps to reinforce the multipath reliability by making efficient use of resources. The protocol selects several nodes located in the radio overlapped area between a pair of paths as bridge nodes for the path-interaction. In order to operate the bridge node efficiently, when the transmission failure has detected by overhearing at each path, it performs recovery transmission to recover the path failure. Simulation results show that proposed protocol is superior to the existing multipath protocols in terms of energy consumption and delivery reliability.

• Journal of Information Processing Systems
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• 제9권3호
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• pp.477-488
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• 2013

Wireless Sensor Networks (WSNs) are comprised of sensor nodes that forward data in the shape of packets inside a network. Proficient packet forwarding is a prerequisite in sensor networks since many tasks in the network, together with redundancy evaluation and localization, depend upon the methods of packet forwarding. With the motivation to develop a fault tolerant packet forwarding scheme a Self-Localized Packet Forwarding Algorithm (SLPFA) to control redundancy in WSNs is proposed in this paper. The proposed algorithm infuses the aspects of the gossip protocol for forwarding packets and the end to end performance of the proposed algorithm is evaluated for different values of node densities in the same deployment area by means of simulations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권12호
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• pp.5442-5463
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• 2016

Designing efficient routing protocols for a wireless sensor network with mobile sinks (mWSN) is a challenging task since the network topology and data paths change frequently as sink nodes move. In this paper, we design a novel lightweight reactive ring based routing protocol called R3, which removes the need of proactively maintaining data paths to mobile sinks as they move in the network. To achieve high packet delivery ratio and low transmission cost, R3 combines ring based forwarding and trail based forwarding together. To support efficient ring based forwarding, we build a ring based structure for a network in a way such that each node in the network can easily obtain its ring ID and virtual angle information. For this purpose, we artificially create a virtual hole in the central area of the network and accordingly find a shortest cycled path enclosing the hole, which serves as base ring and is used for generating the remaining ring based structure. We accordingly present the detailed design description for R3, which only requires each node to keep very limited routing information. We derive the communication overhead by ring based forwarding. Extensive simulation results show that R3 can achieve high routing performance as compared with existing work.

• 한국통신학회논문지
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• 제24권6A호
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• pp.832-844
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• 1999

본 논문에서는 IETF에서 표준화가 진행중인 mobile-IP 프로토콜을 분석하고, 핸드오버가 발생할 경우, 그 성능을 개선하기 위한 방안을 제시하였다. 캐쉬 agent를 통해 이동 호스트에 대한 이동성 바인딩 정보를 관리하도록 함으로서 효율적인 이동성 지원이 가능하도록 하였다. 또한, 핸드오버 수행 시 이동 호스트가 foreign agent의 변경 사실을 인지하고, 새로운 foreign agent에 등록 메시지를 전송할 때까지의 시간동안 이전 foreign agent에서 발생하는 데이터 패킷의 손실을 버퍼링과 forwarding을 통해 방지하였다. 핸드오버에 따른 데이터 패킷의 전송성능에 대한 시뮬레이션을 수행한 결과, 제안한 방안이 전송지연과 처리율 측면에서 기존의 방안보다 우수한 성능을 보장할 수 있는 방안이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권5호
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• pp.1929-1950
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• 2020

Reliable and secure data transmission in the application environment assisted by the wireless sensor network is one of the major challenges. Problem like blind forwarding and data inaccessibility affect the efficiency of overall infrastructure performance. This paper proposes routing protocol for forwarding and error recovery during packet loss. The same is achieved by energy and hops distance-based formulation of the routing mechanism. The reachability of the intermediate node to the source node is the major factor that helps in improving the lifetime of the network. On the other hand, intelligent hop selection increases the reliability over continuous data transmission. The number of hop count is factor of hop weight and available energy of the node. The comparison over the previous state of the art using QualNet-7.4 network simulator shows the effectiveness of proposed work in terms of overall energy conservation of network and reliable data delivery. The simulation results also show the elimination of blind forwarding and data inaccessibility.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.5928-5947
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• 2019

Multicast Mesh based Mobile Ad-hoc NETworks (MANETs) provide efficient data transmission in energy restraint areas without a fixed infrastructure. In this paper, the authors present an improved version of protocol SLIMMER developed by them earlier, and name it SLIMMER-SN. Most mesh-based protocols suffer from redundancy; however, the proposed protocol controls redundancy through the concept of forwarding nodes. The proposed protocol uses remaining energy of a node to decide its energy efficiency. For measuring stability, a new metric called Stability of Node (SN) has been introduced which depends on transmission range, node density and node velocity. For data transfer, a weighted cost function selects the most energy efficient nodes / most stable nodes or a weighted combination of both. This makes the node selection criteria more dynamic. The protocol works in two steps: (1) calculating SN and (2) using SN value in the weighted cost function for selection of nodes. The study compared the proposed protocol, with other mesh-based protocols PUMA and SLIMMER, based on packet delivery ratio (PDR), throughput, end-to-end delay and average energy consumption under different simulation conditions. Results clearly demonstrate that SLIMMER-SN outperformed both PUMA and SLIMMER.

• Industrial Engineering and Management Systems
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• 제15권3호
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• pp.268-277
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• 2016

Load balancing is a significant technique to prolong a network's lifetime in sensor network. This paper introduces a hybrid approach named as Load Distributing Hybrid Routing Protocol (LDHRP) composed with a border node routing protocol (BDRP) and greedy forwarding (GF) strategy which will make the routing effective, especially in mobility scenarios. In an existing solution, because of the high network complexity, the data delivery latency increases. To overcome this limitation, a new approach is proposed in which the source node transmits the data to its respective destination via border nodes or greedily until the complete data is transmitted. In this way, the whole load of a network is evenly distributed among the participating nodes. However, border node is mainly responsible in aggregating data from the source and further forwards it to mobile sink; so there will be fewer chances of energy expenditure in the network. In addition to this, number of hop counts while transmitting the data will be reduced as compared to the existing solutions HRLBP and ZRP. From the simulation results, we conclude that proposed approach outperforms well than existing solutions in terms including end-to-end delay, packet loss rate and so on and thus guarantees enhancement in lifetime.