• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.2
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• pp.67-73
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• 2008

Reconfigurable radio technology is needed to reconstruct frequency and modem functionality, which can be different within various regions. In addition, it makes it possible for a single mobile handset to support various standards of wireless communication, and thus plays a key role inmobile convergence. A MMIC VCO(Monolithic Microwave Integrated Circuit Voltage Controlled Oscillator) has been developed to produce high power and wide bandwidth that adapts the Clapp-Gouriet type oscillator for series feedback. We were fabricated based on the 0.15um pHEMT from TRW. The MMIC VCO was connected to an alumina substrate on the carrier for testing. This MMIC VCO module shows good performance when compared with existing VCOs. Futhermore, it has potential as a reconfigurable MMIC VCO for ubiquitous communications such as LMDS (Local Multipoint Distribution Service), VSAT, Point to Point Radio and SATCOM.

• Journal of the Korean Magnetics Society
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• v.23 no.2
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• pp.68-76
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• 2013

Currently, wireless power transmission technology based on magnetic induction was employed in battery charger for smart phone application. The system consists of wireless power transmitter in base station and receiver in smart phone. Size and thickness of receiver was strictly limited in the newest smart phone. In order to achieve high efficiency of a tiny small wireless power receiver module, sub-millimeter thick electromagnetic wave shielding sheet having high permeability and Q was essential component. It was found that magnetic field from transmitter to receiver can be intensified by sufficient shielding cause to minimize leakage magnetic flux by those magnetic properties. This leads to high efficiency of wireless power transmission and protects crucial integrated circuit of main board from electromagnetic noise. The important soft magnetic materials were introduced and summarized for the current small-power wireless power charger and NFC application and mid-power home appliance and high-power automotive application in the near future.

• Journal of Communications and Networks
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• v.2 no.1
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• pp.46-57
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• 2000

Ongoing standardization effort on 3G cellular system in 3GPP (UNTS) is based on GPRS core network and promises a global standard for systems capable of offering ubiquitous access to internet for mobile users. Considered radio access systems(FDD CDMA, TDD CDMA, and EDGE) are optimized for robust mobile use. However, there are alternative relatively high-rate radio interfaces being standardized for WLAN (IEEE802.11 and HIPER-LAN/2) which are capable of delivering significantly higher data rates to static or semi-static terminals with much less overhead. Also WPANs(BLUETOOTH, IEEE802.15), which will be present in virtually every mobile handset in the near future, are offering low cast and considerable access data rate and thus are very attractive for interworking scenarios. The prospect of using these interfaces as alternative RANs inthe modular UMTS architecture is very promising. Additionally, the recent inclusion of M-IP in the UMTS R99 standard opens the way for IP-level interfacing to the core network. This article offers an overview into WLAN-Cellular interworking. A brief overview of GPRS, UMTS cellular architectures and relevant WLAN standards is given. Possible interworking architectures are presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1856-1862
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• 2010

Last rapidly changing mobile handset market in many industries, as well as market conditions affect the prevalence of various content types of consumer spending in general is affecting. Changes in mobile handset market by separating the various consumer-tier analysis, or differentiated in consumers' purchasing behavior are being reflected in the property analysis and overview of customer satisfaction can be assessed by measuring. These mobile devices and the purchase of the devices to investigate the tendency to analyze and weigh the various content industries, you can see how important one can be considered. The development of mobile communication systems and wireless internet and multimedia applications can lead the industry accelerated. In this study, tried to investigate that the mobile communication systems in consideration of the special form of mobile handsets, and customer satisfaction of mobile phone handsets, and the relationship between customer loyalty. Outcome of this study, the mobile properties and the mobile handset brand, price, design and related details to be statistically significant variables were analyzed. In this study, the characteristics of future mobile handset market with a wide range of content-based guidelines for the development of the industry is expected to be able to provide.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.265-272
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• 2007

In this paper, a frequency changeable antenna using dual half wavelength loaded line structure is proposed for multiband mobile handset applications. The proposed antenna has a capability of independent frequency shift by controlling two added inductance values in two different bands. Experimental results indicate that the proposed antenna provides enough effective bandwidth to cover $CELLULAR(824\sim894\;MHz)$, $EGSM(880\sim960\;MHz)$, $DCS1800(1,710\sim1,880\;MHz)$, $PCS1900(1,850\sim1,990\;MHz)$ and $WCDMA(1,920\sim2,170\;MHz)$ bands and peak gain variation is only 0.54 dB.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2718-2721
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• 2011

This research developed a remote communication system for automatic water meter reading and charge calculation from the field of a house or apartment complexes within the same district. Developed system was applied to perform measurements of the pulse-sensing technology, the minimum power consumption, temperature compensation, short-range wireless communications technology, the handset and wireless communication capabilities of the DB management embedded software to efficiently control. Through this reading-related tasks that are required in a temporal, material and human resources can be minimized.

• Smart Media Journal
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• v.2 no.3
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• pp.10-16
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• 2013

NFC (Near Field Communication) was developed by SONY, NXP in 2002 and in 2003 respectively. It is one type of standard shore-range wireless communication system which operates in 13.56 MHz frequency band, within 10 cm distance and enables data transfer between devices with maximum rate of 424kbps. Various studies have been done on NFC technology and many handset manufacturers such as Apple, Google, Samsung Electronics Co., are trying to expand their market for new mobile services using this technology. This paper analyses the NFC standard technology, its trends and prospects in chapter II, which is followed by NFC systems and communication method in chapter III, and eventually NFC trends and future views is explained in chapter IV.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.71-75
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• 2008

The big issue according to the advance of wireless internet is the design of on-line game under mobile computing environment. The current mobile games have constraints in implementation of on-line game due to the low performance processor. small memory size and short battery time. Therefore, nowadays one-button games which are simple and easy to manipulate, have attracted great interests. In this paper, we designed and implemented the trandition Jeki-chaki game, which is a kind of one-line game, using a mobile handset.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2583-2605
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• 2016

Fingerprint positioning is a main stream and key technique for seamless positioning systems. In this paper, we develop a performance evaluation testbed for fingerprint based Wireless Local Area Network (WLAN) positioning system. The testbed consists of positioning server, positioning terminal, Access Point (AP) units, positioning accuracy analysis system and testing scenarios. Different from other testbeds tended to focus on testing in same situation, in the proposed testbed, a couple of scenarios are set to test the positioning system including indoor and outdoor environments. Handset-side positioning mode and network-side positioning mode are provided simultaneously. Variety of motion models, such as static model, low-speed model and high-speed model are considered as well as different positioning algorithms. Finally, some implementation cases are analyzed to verify the credibility of the testbed.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.136-145
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• 2006

Two major processing technologies of GaAs HBT and pHEMT have been released in production at Win Semiconductors corp. to address the strong demands of power amplifiers and switches for both handset and WLAN communications markets. Excellent performance with low processing cost and die shrinkage features is reported from the manufactured MMICs. With the stringent tighter manufacturing quality control WIN has successfully become one of the major pure open foundry house to serve the communication industries. The advancing of both technologies to include E/D-pHEMTs and BiHEMTs likes for multifunctional integration of PA, LNA, switch and logics is also highlighted.