• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.47-52
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• 2014

Recently, the interest of Wireless Power Transmission(WPT) has been increased for Mobile device application. It is necessary to analyze interference between wireless devices for the efficient use of frequency resource. The Minimum Coupling Loss(MCL) method and the Monte Carlo(MC) method were used for the interference analysis. In this paper, the impact of the 3rd order harmonics of the wireless charger for Cellular Phone on the existing Radio Modem was analyzed. As a result, the separation distance and the allowable number of interferer on the basis of service radius were obtained to protect the Radio Modem from the wireless charger for Cellular Phone.

• Journal of the Korea Society of Computer and Information
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• v.24 no.5
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• pp.1-9
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• 2019

In this paper, we propose the algorithms which determine 1) the efficient anchor-node visiting route of mobile sink in terms of energy supply and 2) the efficient energy amount to be charged to each anchor node, by using the information of each anchor node and the mobile sink. Wireless sensor networks (WSNs) using mobile sinks can be deployed in more challenging environments such as those that are isolated or dangerous, and can also achieve a balanced energy consumption among sensors which leads to prolong the network lifetime. Most mobile sinks visit only some anchor nodes which store the data collected by the nearby sensor nodes because of their limited energy. The problem of these schemes is that the lifetime of the anchor nodes can be shorten due to the increased energy consumption, which rapidly reduces the overall lifetime of WSN. This study utilizes a mobile sink capable of wireless power transmission to solve this problem, so a mobile sink can gather data from anchor nodes while charging energy to them. Through the performance verification, it is confirmed that the number of blackout nodes and the amount of collected data are greatly improved regardless of the size of the network.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.7
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• pp.728-736
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• 2014

Due to the recent development of mobile wireless telecommunication, RRHs(Remote Radio Heads) are widely being utilized to expand the cell coverage. Wire-link, an existing connection between DU(Digital Unit) and RRH through fiber cables, is considered to have limitations in relation to cost for a wide range of applications. This paper focuses on replacing the wire-link by wireless transmission using millimeter-wave, and implementing cellular network system through RRH from a remote location. After an influence element analysis on millimeter-wave wireless link transmissions, a comparative analysis between wireless link and an existing fiber link method will be made by utilizing currently commercialized LTE(Long Term Evolution), to prove the compatibility of millimeter-wave wireless link RRH method in replacing fiber link method without a significant decline in data transmission performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.583-584
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• 2011

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.59.1-59.1
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• 2008

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.79.2-79.2
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• 2008

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.213-216
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• 2000

In this paper, performance of a CDMA-based packet transmission system is analyzed and simulated in a wireless infrared channel. The indoor wireless infrared channel is modeled as a non-directed diffuse link. The pulse position modulation (PPM) is used as a modulation scheme. From the simulation results, it is shown that the RS coding is very effective in improving the packet-delay characteristics of the CDMA-based packet transmission system. The performance improvement is more significant especially when the infrared channel is in a worse condition.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.194-199
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• 1998

In the atmospheric wireless optical communication system, the low power transmission can be accomplished by the high directivity of laser beam. But, the transmitted optical signal undergoes the serious influences by the atmospheric effects like absorption, scattering, and turbulence because the transmission channel is the atmospheric space. In this paper, therefore, we obtain the link equation for an atmospheric wireless optical LOS communication link under the atmospheric effects and find the repeaterless transmission length to estimate the system performance through the computer simulation. From the results of the computer simulation, we present the transmission length that is possible to transmit without a repeater at given data rates and know that data rate is decreased rapidly when the transmission length is increased slightly at given bit error rate.

• Journal of Information Technology Services
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• v.19 no.3
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• pp.89-100
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• 2020

The wireless power transmission market is growing at an average annual rate of 51.5% from $ 16.4 billion in 2015 to $ 131.1 billion in 2020. However, there are limitations to commercialization due to the development of standards and technologies. Thus, this study identified trends in standards and regulations by market and by country. The research collected and filtered a total of 69,488 worldwide wireless power transfer patents by June 2019 and extracted a total of 28,555 patents. Based on this, technology development status was analyzed and predicted. In this study, long-distance and short-range technology development with high technology development difficulty and low technology development ratio could lead to growth of the entire wireless charging market. It is analyzed that investment and policy preparation are necessary to secure source technology for long-distance / near technology development than China, Japan and Europe.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.449-452
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• 2005

For home networking system with a function of air quality monitoring, a wireless sensor module with several air quality monitoring sensors was developed for indoor environment monitoring system in home networking. The module has various enlargements for various kinds of sensors such as humidity sensor, temperature sensor, CO2 sensor, flying dust sensor, and etc. The developed wireless module is very convenient to be installed on the wall of a room or office, and the sensors in the module can be easily replaced due to well designed module structure and RF connection method. To reduce the system cost, only one RF transmission block was used for sensors' signal transmission to 8051 microcontroller board in time sharing method. In this home networking system, various indoor environmental parameters could be monitored in real time from RF wireless sensor module. Indoor vision was transferred to client PC or PDA from surveillance camera installed indoor or desired site. Web server using Oracle DB was used for saving the visions by web-camera and various data from wireless sensor module.