• 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 Internet of Things and Convergence
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• v.8 no.4
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• pp.17-23
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• 2022

NB-IoT and LTE Cat.M1 based on LPWA(Low Power Wide Area) are commercialized and serviced by mobile carriers. As the demand for IoT devices is increased, the number of subscribers to these services is also increasing. In the beginning of service, there was no issue that eNB capacity for NB-IoT and LTE Cat.M1. However, as the number of subscribers increases, there is an issue that the eNB capacity for these service is insufficient. Active UE capacity issue may cause overload by continuous increase and temporary increase. In this paper, we propose a solution to solve the problem of LTE RRC(Radio Resource Control) Active UE capacity shortage and base station overload caused by the increase of NB-IoT and LTE Cat.M1 UE in same eNB. The proposed solution can increase a cell capacity without cell division and additional eNB, and can also improve the service quality of these UEs.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.472-474
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• 2019

We propose an antenna for subminiature sensor node in the marine IoT service based on low power wide area (LPWA) network. The proposed antenna is designed for multi-band in ISM band. The specification of the proposed antenna expressed here is also for multi-band service.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1599-1610
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• 2019

Intelligent services have expanded as Internet of Things (IoT) technology has evolved and new requirements emerge to accommodate various services. One new requirement is transmitting data over long distances with low-power. Researchers have developed low power wide area (LPWA) network technology to satisfy the requirement; this can improve IoT network infrastructure and increase the range of services. However, network coverage expansion causes several problems. The traffic load is concentrated at a specific gateway, which causes network congestion and leads to decreased transmission efficiency. Therefore, the approach proposed in this paper attempts to recognize and then avoid congestion through gateway channel hopping. The LPWA network employs multiple channels, so wireless channel hopping is available in a gateway. Devices that are not delay sensitive wait for the gateway to reappear on their wireless channel; delay sensitive devices change the wireless channel along the hopping gateway. Thus, the traffic load and congestion in each wireless channel can be reduced improving transmission efficiency. The proposed approach's performance is evaluated by computer simulation and verified in terms of transmission efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.444-452
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• 2017

Recently, a demand of Internet-of-things (IoT) rises dramatically and an interest in Low Power Wide Area (LPWA) grows larger accordingly. In this paper, performance in LoRa which is included in LPWA standard is analyzed. Particularly, after measuring Received Signal Strength Indication (RSSI) of received signal on Line-of-sight (LoS) and Non-line-of-sight (NLoS) environment and it is compared with RSSI which theoretical path loss model is applied to. Among many path loss models, the simulation for theoretical RSSI use Log-distance, Two-ray model and Okumura-Hata model that is based on the test database. Consequently, the result of Okumura-Hata model is the most similar with the measured RSSI. When a network based on LoRa is built, this result can used to decide optimal node arrangement.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.10
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• pp.259-268
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• 2018

Due to the development of cities and the increase of vehicles, effective control of parking space management service in cities is needed. However, the existing parking lot management system does not provide limited or convenient service in terms of space and time. In this paper, we propose distributed parking space management service based on large scale LPWA (Low-Power Wide-Area). The parking sensor collects parking space information from the parking lot and is transmitted over a low-power wide network. All parking data is processed and analyzed in the IoT cloud. Through a parking space management service system in all cities, users are given the temporal convenience of determining the parking space and the area efficiency of the parking space.

• Journal of Advanced Navigation Technology
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• v.22 no.1
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• pp.37-42
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• 2018

Recently, there have been many studies on the IoT environment in which the sensors attached to the equipment automatically transmit and process the site information in real time through the network to control the equipment. The core of such a system is a network for data transmission and reception, and a wired network with wide transmission distance is a priority. However, in the case of a wired network, there is a problem that the time and cost consumed to configure the communication is higher than that of the wireless. In this paper, we propose LPWA - based wireless data transmission system using LPWA and BLE communication to solve this problem. The proposed system collects data from equipment through BLE and transmits data to the server using LPWA. Experimental results show that the spreading factor of maximum length of LPWA is 8, and the minimum length is 9.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.620-625
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• 2017

Recently, the solar module for charging internet devices is installed in crowded areas to offers services so that people can charge their smartphones or tablets. But this charging module can not be linked with the information related to a bus approach so people are subject to let their belongings such as smartphone, tablet pc at the bus stop while they are still charging it. This paper proposes a system to inform the smart phone when the bus is accessed by using the LPWA technology and BLE technology to resolve such under-failures. This experimental result showed that the power usage of LPWA based bus entry systems is an average of X, confirming that the long period usage of low-power can be possible for low power consumption in this results, enabling information on the bus to be transmitted to smart phones using Advertising mode of BLE.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.695-702
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• 2020

Recently, as research on smart farms has been actively conducted, indoor environment control, such as a green house, has reached a high level. However, In the field of forestry where cultivation is carried out in outdoor, the use of ICT is still insufficient. In this paper, we propose LPWA-based forest growth environment collection and big data analysis system using ICT technology. The proposed system collects and transmits the field cultivation environment data to the server using small solar power generation and LPWA technology based on the oneM2M architecture. The transmitted data is constructed as big data on the server and utilizes it to predict the production and quality of forest products. The proposed system is expected to contribute to the production of low-cost, high-quality crops through the fusion of renewable energy and smart farms. In addition, it can be applied to other industrial fields that utilize the oneM2M architecture and monitoring the growth environment of agricultural crops in the field.