• 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.

• 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.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.1
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• pp.49-56
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• 2023

With the development of technology worldwide, bridges are becoming larger, and the number of old bridges is also rapidly increasing. Monitoring the structural health of large, aging bridges is essential to preventing large-scale accidents. In this study, the application of a LoRa low-power wide-area network (LPWAN)-based wireless measurement system was investigated, and a LoRa wireless measurement system was established in the cable-stayed bridge section of Cheonsa Bridge, located in Shinan-gun, Jeollanam-do, Korea. The applicability of the LoRa LPWAN-based wireless monitoring system to large marine bridges was reviewed by comparing the performance and economic feasibility with wire-based monitoring systems that were built and operated by establishing a measurement system for the pylons, cables, and reinforcing girders of the bridge.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.313-316
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• 2021

In the IoT(IoT: Internet of Things) environment, network configuration is essential to collect data generated from objects. Various communication methods are used to process data of objects, and wireless communication methods such as Bluetooth and WiFi are mainly used. In order to collect data of objects, a communication module must be installed to collect data generated from sensors or edge devices in real time. And in order to deliver data to the database, a software architecture must be configured. Data generated from objects can be stored and managed in a database in real time, and data necessary for industrial safety can be extracted and utilized for industrial safety service applications. In this paper, a network environment was constructed using a LoRa(LoRa: Long Range) gateway to collect object data, and a client/server data collection model was designed to collect object data transmitted from the LoRa module. In order to secure the resources necessary for data collection and storage management without data leakage, data collection should be possible in real time. As an application service, location data required for industrial safety can be stored and managed in a database in real time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.207-211
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• 2019

Research and development are underway to connect the network to all things in the world and to manage the objects through the Internet. The Internet of Things is expected to play an important role in building ecosystem of next generation mobile communication service. The most significant communication technology is LPWAN. In this paper, we analyze the performance according to each data transmission rate to reduce and manage resource waste by using many LPWAN nodes more efficiently in accordance with the demands of the times. The LPWAN communication technology used in this paper was designed based on LoRaWAN, a long-distance low-power wireless platform developed by Semtech, and analyzed by implementing a virtual IoT base using Network Simulator-3.

• International journal of advanced smart convergence
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• v.7 no.3
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• pp.23-36
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• 2018

In wireless communication, efficient spectrum usage is an issue that has been an attractive research area for many technologies. Recently new technologies innovations allow compact radios to transmit with power efficient communication over very long distances. For example, Low-Power Wide Area Networks (LPWANs) are an attractive emerging platform to connect the Internet-of-Things (IoT). Especially, LoRa is one of LPWAN technologies and considered as an infrastructure solution for IoT. End-devices use LoRa protocol across a single wireless hop to communicate to gateway(s) connected to the internet which acts as a bridge and relays message between these LoRa end-devices to a central network server. The use of the (ISM) spectrum sharing for such long-range networking motivates us to implement spectrum sensing testbed for cognitive radio network based on LoRa and GNU radio. In cognitive radio (CR), secondary users (SUs) are able to sense and use this information to opportunistically access the licensed spectrum band in absence of the primary users (PUs). In general, PUs have not been very receptive of the idea of opportunistic spectrum sharing. That is, CR will harmfully interfere with operations of PUs. Subsequently, there is a need for experimenting with different techniques in a real system. In this paper, we implemented spectrum sensing for cognitive radio networks based on LoRa and GNU Radio, and further analyzed corresponding performances of the implemented systems. The implementation is done using Microchip LoRa evolution kits, USRPs, and GNU radio.

• The Journal of the Convergence on Culture Technology
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• v.3 no.4
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• pp.185-189
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• 2017

According to the rapid growth of Internet of Things (IoT) technology, we are able to connect between human and objects and between objects through network, allowing transmission and reception of information beyond the limits of space. These days, Low Power Wide Area (LPWA) technologies becomes popular more and more, to implement IoT infrastructure effectively. In this paper, this study aims to analyze LoRa, one of LPWA technologies, and suggest IoT security technology using LoRa to minimize threats to security.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.608-614
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• 2021

Currently, blockchain-based public cryptocurrency (hereinafter referred to as cryptocurrency) cannot acquire status as a currency for transaction due to the economic policies of each country, but it is used as an alternative currency transaction method due to individual circumstances of some Internet users. With this trend, it is predicted that such cryptocurrency can be used in real life beyond the Internet in the near future. In this paper, a technical method for designing a cryptocurrency payment system based on LoRaWAN that can easily build a wireless Internet network infrastructure at low cost as a way to activate the use of cryptocurrency in real life is presented based on the LoRaWAN standard.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.417-419
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• 2016

Internet of things(IoT) services should be available to provide unattended operation in a remote area, long battery life, low-cost infrastructure, two-way communication platform. Urban transit in Busan is made up of the wire-based infrastructure except for voice infrastructure of transmit/receive and new data infrastructure is required for Internet of things(IoT) services. Urban transit environments in Busan were analyzed in order to apply LoRa Wireless Network(the standard communication way of IoT) and proposes a building after a Disaster Evacuation System.