• KNOM Review
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• v.22 no.2
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• pp.29-38
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• 2019

The rapid growth of IoT (Internet of Things) owing to the advancement and spread of technologies such as wireless networks, communication modules, sensors, smart terminals, etc. enables the development of new services in diverse public and private sectors. In particular, research on IoT technology and its applications has increased in the field of science. To establish an IoT infrastructure in this field, KREONET launched the wireless IoT network, called ScienceLoRa, based on low power wide area network (LPWAN). ScienceLoRa aims to collect a variety of data from sensors and utilize and analyze the collected data for research in a variety of scientific fields. In this article, the authors present the concept, current status, applications and future plans of ScienceLoRa.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.5
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• pp.1540-1560
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• 2022

Latest technological innovation in the development of compact lower power radios has led to the explosion of Internet of Things. With Wi-Fi, Zigbee and other physical layer protocols offering short coverage area there was a need for a RF protocol that had a larger coverage area with low power consumption. LoRa offers Long Range with lower power consumption. LoRa offers point to point and point to multipoint connections. with Single hop communication in place the need for routing protocols are eliminated. LoRa Wide Area Network stack can accommodate thousands of nodes under a single LoRa gateway with a single hop communication between the end nodes and LoRaWAN gateway. This paper takes an experimental approach to analyze the basic physical layer parameters of LoRa and the practical coverage offered by a LoRaWAN under highly dense urban conditions with variable topography. The insights gained from the practical deployment of the LoRaWAN network, and the subsequent performance analysis is used to design a novel public utility monitoring platform. The second half of the papers is designing a robust platform to integrate both existing wired sensor water meters, current and future generation wireless water meters. The Common Automated Metering Platform is designed to integrate both wired sensors and wireless (LoRaWAN and Wi-Fi) supported water meters. This integrated platform reduces the number of nodes under each LoRaWAN gateway and thus improves the scalability of the network. This architecture is currently designed to accommodate one utility application but can be modified to integrate multi-utility applications.

• Journal of KIISE
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• v.44 no.7
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• pp.733-741
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• 2017

LPWAN(Low Power Wide Area Network) technology is M2M (Machine to Machine) networking technology for the Internet of Things. The technology is designed to support low-power, long-distance and low-speed communications that are typical of LoRaWAN(Long Range Wide Area Network). To exchange inter-object information using a LoRaWAN, the link performances for various environments must be known. however, active performance analysis research that is based on an empirical environment is nonexistent. Therefore, this paper empirically evaluates the performance of the LoRa (Long Range) link, a physical communication technology of the LoRaWAN for various variables that may affect the link quality in indoor and outdoor environments. To achieve this, a physical performance monitoring system was designed and implemented. A communication experiment environment was subsequently constructed based on the indoor and outdoor conditions. The SNR(Signal to Noise Ratio), RSSI(Received Signal Strength Indication), and the PDR(Packet Delivery Ratio) were evaluated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.15-20
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• 2019

Due to evolving IoT technologies, the various application services using clothing, sport equipment, and wearable devices equipped with extream small communication devices have been actively developed. On the other hands, since these serveices requires long distance communications, Long Distance wireless communication technology LPWAN Research has been proceeded due to limitation of the commuication distance of Wi-Fi and Zigbee which were considered as representative technologies for IoT. Iin this paper, we introduces LoRa technology in detail, which is a non-band network technology among LPWAN technologies, and investigates the use cases of domestic as well as international countries.

• 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.

• KIISE Transactions on Computing Practices
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• v.24 no.1
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• pp.1-9
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• 2018

Low-power long-range networks (LoRa) has a comprehensive coverage of up to 30 km, so that long-range positioning is possible. However, the position error in the current LoRa environment is over 500 m. This makes it difficult to use practical location services in the LoRa environment. In this paper, we propose a method to improve the position accuracy by correcting an inaccurate visual error when sending a signal from a mobile node to a gateway through the reference node of each zone in the LoRa environment. Experiments were carried out using MATLAB, and a radio propagation algorithm, the Hata model, was used to cancel out the stationary noise and to evaluate the environmental noise. Experimental results showed that the error range decreased as the number of reference nodes increased and a mobile node approach the reference node.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.2
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• pp.113-119
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• 2017

In this paper, we have shown the performance analysis results of the LoRa low power wide area network under duty cycle local regulation in Korean RFID/USN frequency band. Especially, we analyzed uplink throughput and data transmission time of a single LoRa end device. From the analysis results, duty cycle regulation, in which a data transmission should be ended within 0.4 second, limits the performance of LoRa network. Therefore, it is necessary to revise Korea's duty cycle regulation referencing EU regulation in order to assess LoRa network in Korea.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.83-90
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• 2018

LoRa (Long Range) is a long-distance, low-power communication technology. Broader range of communication than NFC technology allows communication without having to install multiple APs and reduces the cost of initial infrastructure deployment. MQTT (Message, Queuing, Telemetry, Transport) protocol is also low power and lightweight protocols. It can increase module persistence and reduce maintenance costs when used with LoRa. In this paper, we developed a system for compiling various environmental information in a factory using LoRa and MQTT. Environmental sensor data from long distances can be monitored by the management system and the facilities in each workshop can be controlled. Performance tests have also shown that the use of LoRa and MQTT is effective in terms of long-distance and power consumption.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.2
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• pp.230-238
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• 2022

Internet of Things(IoT) is a communication technology that collects information of object remotely and controls the function of object by adding a communication function to object that does not have a communication function. For the IoT, various communication technologies such as Wi-Fi, 3GPP, and Bluetooth are available, and Long Range(LoRa) is communication technologies specialized in the IoT concept. LoRa is a communication technology that support long-distance, low-power, and low-speed communication, and is suitable for collecting information generated form object in remote equipment and controlling equipment. Because of these characteristics, it is used in many application field, and various performance improvement studies are in progress. This paper intends to propose an ultra-long-range LoRa communication module that can be used in a wider range of applications. We design and implement hardware, firmware, and application software for testing to develop ultra-long-range LoRa communication modules. The implemented module will be tested in a real environment to verify its performance and to check its utilization.

• Journal of the Korea Society of Computer and Information
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• v.29 no.1
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• pp.1-9
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• 2024

This paper proposes an integration of the ED-H scheduling algorithm, known for optimal real-time scheduling, with the LoRaEnergySim simulator. This integration facilitates the simulation of interactions between real-time scheduling algorithms for tasks with time constraints in Class-A LoRaWAN Class-A devices using a super-capacitor-based energy harvesting system. The time and energy characteristics of LoRaWAN status and state transitions are extracted in a log format, and the task model is structured to suit the time-slot-based ED-H scheduling algorithm. The algorithm is extended to perform tasks while satisfying time constraints based on CPU executions. To evaluate the proposed approach, the ED-H scheduling algorithm is executed on a set of tasks with varying time and energy characteristics and CPU occupancy rates ranging from 10% to 90%, under the same conditions as the LoRaEnergySim simulation results for packet transmission and reception. The experimental results confirmed the applicability of co-simulation by demonstrating that tasks are prioritized based on urgency without depleting the supercapacitor's energy to satisfy time constraints, depending on the scheduling algorithm.