• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.913-922
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• 2020

In this paper, we propose a LoRa communication module using the LoRa RF module of Murata Electronics is designed to configure the IoT digital meter remote meter reading and a method of configuring a remote meter reading network by collecting multiple meter data in a DCU (Data Concentrate Unit) to configure a network with LoRaWAN. The developed system can be installed more easily and economically in the network configuration than the existing system by allowing the meter to be directly connected to the network or matched with a DCU to connect to the network according to the configuration of the consumer. The developed system was constructed using a digital water meter as an example, but it can also be applied to remote meter reading of the metered values of other meters such as electricity, water, gas, hot water and calorie meters. The main development contents are the design, configuration, and construction of digital meters, LoRa modules and DCUs, and how to connect the LoRaWAN network and transmit meter data to the server. By networking these devices, the system is configured, and the actual LoRaWAN communication is tested and the result is shown.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.129-132
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• 2019

This paper explains the design idea of a multi-Hop network for LoRaWAN. First, the existing LoRaWAN communication method(Single-Hop) will be described based on the standard specification. It then discusses technical considerations when converting from LoRaWAN to a multi-hop network. Finally, we introduce our ideas in this paper.

• Journal of Practical Engineering Education
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• v.15 no.3
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• pp.549-555
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• 2023

The representative technology of the WWAN wireless communication network used in the Internet of Things is LoRa communication technology, and LoRa communication uses the ISM band. The 920 MHz (920.9 MHz~923.3 MHz) band frequency, which is used as a domestic LoRa frequency, had a problem in performing LoRa network practice in the curriculum using a commercially available LoRa modules that have been used in Europe and the United States because of different frequency band, but a RYLR896 LoRa module was developed that allowed RF frequency to be programmed. With this module, this paper confirmed that the frequency can be set at a specified frequency in Korea using AT commands. In addition, using these RYLR896 LoRa modules, a LoRa network consisting of end nodes and gateways was constructed and practiced to confirm that development equipment capable of practicing the RYLR896 LoRa module and IoT was operating normally.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.105-107
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• 2019

최근 몇 년간 소량의 데이터를 송수신하는 Massive IoT 네트워크에 많은 관심을 가지고 있다. 이러한 환경을 구축하기 위해서 저전력 광역 네트워크(LPWAN) 기술 중 LoRa(Long Range) 네트워크를 사용하고 있다. 대부분의 IoT 응용 서비스는 디바이스가 장시간 안정적으로 작동해야 하므로 에너지 효율성을 중점으로 두고 LoRa 디바이스의 수명을 최대화하기 위한 디바이스의 여러 동작들을 설계하는 에너지 소비 모델링이 중요하다. 따라서 본 논문에서는 LoRa Class B 통신 방식의 에너지 소비 모델을 정의하고 성능을 평가한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.897-906
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• 2022

In this paper, we propose a novel MAC protocol based on the harmonic transmission of ACK, called HAT-LoRa, for improving the reliability and the utilization in multiple gateway LoRa Networks. LoRa is basically vulnerable to collision due to the primitive pure ALOHA-like MAC. Whereas data frame delivery can be guaranteed by the transparent bridge of multiple receiving gateways, ACK is still transmitted by a single gateway in LoRa Network. HAT-LoRa provides the augmented reception opportunity of ACK via the simultaneous transmissions of identical ACK in multiple spreading factors. The proposed method reduces the expected transmission times of ACK double gateway environment as well as single gateway environment, by 55 and 60% in maximum, by 35% and 40% in average, in a single- and double-gateway environment, respectively. Especially, it outperforms under the environment where the distance between end device and gateways are similar to each other.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.3
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• pp.440-448
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• 2021

This paper presents problems of network technology in smart grid and implements a blockchain-based LoRa multi-hop network to solve them. Since some smart grid applications are operated in harsh environments, it is difficult to establish communication infrastructure. We propose a LoRa network with multi-hop using the Flooding routing protocol. Smart grid environment composes an independent network using various power grid protocols depending on the application. Since this has a problem that an independent infrastructure must be established for each network, a single gateway device supports multiple power grid protocols to implement a method for network integration. Lastly, the author applied Hyperledger-based blockchain to the LoRa network to ensure the integrity of data in a smart grid environment, and strengthened security by physically distributing it. After constructing the three suggestions on the actual test bed, we confirmed that the network operates normally through experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.283-288
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• 2019

LPWA (Low Power Wide Area) networks have been considered as one of the technologies which can be implemented in IoT (Internet of Things) applications by providing less power and longer communication range compared with existing wireless technologies. In this paper, we investigate LoRa which is one of representative technologies for LPWA networks. First, we present general properties and several technologies of LPWA networks. Then, the technical specification, properties, and pros/cons of LoRa are studied. Finally, we discuss analysis of LoRa's performance and its ehancement technologies by focusing on physical layer and MAC (Medium Access Control) layer.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.95-99
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• 2019

In this paper, the uplink data transmitted from LoRa node is received and decomposed in LoRaWAN Network Server and converted into data with key and value. The data is converted into the data format required by the existing oneM2M platform, and transmitted. The oneM2M platform stores the data, another system for transmitting the data is implemented so that the processing for the data can be started immediately.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.113-119
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• 2020

The IoT-based sensor network is one of the methods that can be efficiently applied to maintain the facilities, such as bridges, at a low cost. In this study, based on LoRa LPWAN, one of the IoT communications, sensor board for cable tension monitoring, data acquisition board for constructing sensor network along with existing measurement sensors, are developed to create bridge structural health monitoring system. In addition, we designed and manufactured a smart sensor node for LoRa communication and established a sensor network for monitoring. Further, we constructed a test bed at the Yeonggwang Bridge to verify the performance of the system. The test bed verification results suggested that the LoRa LPWAN-based sensor network can be applied as one of the technologies for monitoring the bridge structure soundness; this is excellent in terms of data rate, accuracy, and economy.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.103-104
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• 2019

최근 스마트시티 구축 사업에서 사물인터넷 기반 서비스 개발이 활발히 진행 중이다. 그 서비스들을 제공하기 위해 사용되어야 할 디바이스 수가 수백만 개까지 증가할 것으로 예상하고 있으며 수백만 개의 디바이스들을 수용하기 위해서는 Massive IoT 네트워크의 환경 구축을 필요로 하고 있다. 따라서 본 논문에서는 Massive IoT 네트워크 환경을 구축하기 위해 저전력 광역 네트워크(LPWAN) 기술 중 LoRa(Long Range) 네트워크가 적용이 가능한지를 LoRaSim을 이용하여 시뮬레이션한다. 시뮬레이션한 결과 중 충돌 횟수를 통해 충동률을 구하고 그래프를 이용하여 신뢰성을 나타내며, Massive IoT 네트워크에 적합성에 대해 분석한다.