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

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2020.07a
• /
• pp.139-142
• /
• 2020

NB-IoT(Narrow Band Internet of Things) is an emerging LPWAN(Low Power Wide Area Network) radio technology. NB-IoT has many advantages like low power, low cost, and high coverage. However low bandwidth and low sampling rates also lead to poor positioning accuracy. This paper proposed a solution to optimize positioning accuracy under the OTDOA(Observed Time Difference of Arrival) approach by utilizing MLR(Multiple Linear Regression) models. Through the MLR model to predict the influence degree of weather(temperature, humidity, light intensity and air pressure) on the arrival time of signal transmission to improve the measurement accuracy. The improvement of measurement accuracy can greatly improve IoT applications based on NB-IoT.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.9
• /
• pp.1026-1037
• /
• 2016

3rd Generation Partnership Project (3GPP) is the progressing standardization of the narrowband IoT (NB-IoT) system to support massive devices for the Internet of Things (IoT) services. The NB-IoT system uses a coverage class technique to increase the performance of the NB-IoT system while serving massive devices in very wide coverage area. A moving device can change the coverage class according to the distance or the channel state between the base station and the moving device. However, in the conventional NB-IoT standard, the performance of the NB-IoT system degrades because the coverage class is changed based on the fixed criterion. This paper proposes the coverage class adaptation schemes to increase the performance of the NB-IoT system by dynamically change the coverage class according to the location or the channel state of the device. Simulation results show that the proposed coverage class adaptation scheme decreases both the signaling overhead and the PDCCH decoding error rate in comparison with the conventional coverage class adaptation scheme in the 3GPP standard.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.06a
• /
• pp.59-61
• /
• 2022

항로표지 시스템은 적은 양의 데이터를 간헐적으로 전송하고 넓은 지역에서 통신이 가능해야 하기 때문에 NB-IoT 시스템은 매우 적합한 기술이다. 본 연구에서는 LTE 시스템과 공존하는 inband-mode NB-IoT 시스템에서 상항링크 간섭을 분석하였다.

• Electronics and Telecommunications Trends
• /
• v.31 no.5
• /
• pp.11-20
• /
• 2016

사물인터넷은 다양한 응용 및 융합 서비스를 창출할 새로운 기회의 장으로 떠오르고 있다. 가트너 등의 시장 조사기관 및 전문가 들의 예측에 따르면 2020년까지 사물인터넷 디바이스는 300~500억 대로 증가할 것이며, 시장 규모는 3,000억 달러를 초과할 것으로 전망하였다. 이러한 거대한 규모의 시장 선점을 위한 기술 간, 업체 간 경쟁도 한층 증대되고 있다. 비 3GPP 계열 LPWA 네트워크는 유럽을 중심으로 이미 서비스가 시작되었으며, 3GPP에서는 LPWA 네트워크 실현을 위해 Narrowband Internet-of-Things(NB-IoT)를 새롭게 소개하였다. NB-IoT는 비 3GPP 계열 LPWA 기술과의 경쟁 속에서도 빠르게 시장에 진입할 것으로 기대된다. 본고에서는 표준화가 완료된 3GPP Release 13 NB-IoT 기술과 Release 14을 목표로 표준화가 진행 중인 NB-IoT enhancement에 대해 기술한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2020.07a
• /
• pp.481-482
• /
• 2020

다양한 재난경보 전달 매체 중 재난문자 서비스는 재난 발생 시 재난 지역과 관련된 대국민 대상으로 재난경보를 빠르고 신뢰성 있게 전송할 수 있는 보편 매체이다. 현재 국내 재난문자 서비스는 2G/4G 셀룰러 환경에서 셀룰러 이동 단말기에 재난문자를 전송한다. 특히 4G 이상의 셀룰러 시스템은 재난문자 전송을 위하여 SIB를 이용한다. 그러나 현 재난문자 서비스는 셀룰러 이동 단말기만 수신이 가능한 한계를 보인다. 재난경보 수신의 성공률을 높이기 위하여 다양한 수신 단말기의 재난문자 서비스 지원이 필수적이다. 현재 NB-IoT는 4G 셀룰러 환경을 기반으로 광범위한 지역에 저전력 서비스를 제공한다. 본 논문에서는 NB-IoT가 재난문자 수신을 위하여 필요한 프로토콜 규격과 NB-IoT 기반의 재난문자 서비스를 위한 네트워크 구조를 제시한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.2
• /
• pp.135-141
• /
• 2019

Internet of thing becomes more active, many sensor devices are increasing. Sensors can use network wired network or use mobile communication network. From the viewpoint of the transmission rate, the mobile communication network can be roughly divided into two types of high-speed communication and low-speed communication. In the case of hundreds of millions of sensors in the mobile communication network, resources are wasted to use high-speed communication. Communication is required to reduce the transmission rate and appropriately allocate resources without wasting such resources. As the Internet of Thing has been activated, Narrowband Internet of Thing(NB-IoT), which is one of the low-power technologies in recent mobile communications, is in the spotlight from various companies. Currently, it can be seen that only NB-IoT or other low power consumption communication has the potential to be able to connect to the Internet with rapidly increasing sensor devices. In this paper, we designed and implemented a heater controller using Huawei NB-IoT communication Module, a server that collects controller information, and an application that allows default settings for devices. The main function of this system is to collect temperature and heater status and give it to the server, control the heater from the server, and set parameters for the heater to operate automatically. The system can be applied to places where wired communication is not established, such as road information, smart agriculture, and small reservoirs as well as heaters.

• Journal of Advanced Navigation Technology
• /
• v.22 no.6
• /
• pp.545-550
• /
• 2018

Ministry of Oceans and Fisheries declared action plan for the electric fishing gear using real name in order to prevent overusing the fishing gear and to reduce discarded fishing gear. It is needed for a technique that can efficiently transmit the information including the type and location of the fishing gear and the user's real name to the fishing boat and the control center using IoT-based communication. The marine tracker buoy system, which is placed on the water for a long time, transmit the position data and the state data of the buoys to the control center in the ground by using NB-IoT channels. In this paper, we propose the algorithm for the low-power operation of the marine tracker buoy system is proposed and test results of current consumption in the marine tracker buoy system with the proposed algorithm is investigated.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.6
• /
• pp.117-122
• /
• 2022

In this paper, we developed a vehicle control terminal using IoT and low-power long-distance communication (NB-IoT) technology. This system collects information on the location and status of a parked vehicle, and transmits the vehicle status to the vehicle owner's terminal in real time with low power to prevent vehicle theft, and in the case of a vehicle in motion, When primary information about the vehicle, such as an impact, is collected and transmitted to the server, the server analyzes the relevant data to generate secondary information on traffic congestion, road damage, and safety accidents. By sending it, you can know the exact arrival time of the vehicle at its destination. This terminal device is an IoT gateway for a vehicle and can be connected to various wired and wireless sensors inside the vehicle. In addition, the data collected from vehicle maintenance, efficient operation, and vehicles can be usefully used in the private or public sector.

• Journal of Korea Water Resources Association
• /
• v.53 no.7
• /
• pp.507-519
• /
• 2020

This study developed the radon measurement system that can be used for crustal movement monitoring and seismic occurrence and prediction, and compared and analyzed the results of test-operated radon measurement system and observed seismic occurrence cases. First, the developed radon measurement system consists of an NB-IoT radon measurement device, data center, data analysis, and data supply server. Because the measured radon data can be remotely trasmitted by using NB-IoT, this system is very suitable for installation and operation in unmaaned groundwater station. Second, the developed radon measurement device was test-operated at two groundwater stations in Gimpo from May to July 2019. The measured radon data was compared with the groundwater-level and electrical conductivity measurement data, and it was confirmed that the radon measurement device developed in this study has some potential for commercialization. Finally, from November 2019 to February 2020, three observed seismic cases and daily measured radon, groundwater-level, electrical conductivity data by the NB-IoT radon measurement device installed at three groundwater stations in Pohang, which is a test-bed, were compared and analyzed. As a result of the analysis, it was confirmed that the seismic occurrence correlated with radon, groundwater level, and electrical conductivity and all of these measured data will be able to provide basic data to help in seismic monitoring and prediction in the future.