• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.4
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• pp.185-204
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• 2009

The USIM(universal subscriber identity module)-unlock introducing in July 1, 2008 might be led to a significant change that mobile service provider's dominance is considerably dispersed to the handset manufacturer and distributor. Under USIM-unlock environment, mobile service provider, handset manufacturer, and distributor have to make their decisions on their handset distribution channel strategies: the closed distribution channel strategy or the open distribution channel strategy. The change of distribution channel strategy between members in distribution channel can be understood as a matter of strategy choice, and we have developed a theoretical model and analyzed how to make a decision for the member's optimal distribution strategy based on 3-person game model between members of mobile phone distribution channel, under both of '1 subscriber-1 handset' and '1 subscriber-multiple handset' assumptions. Under '1 subscriber-1 handset' assumption, the closed strategy controlled by mobile service provider is all players' optimal solution because the maximum size of the mobile phone market is limited by subscribers. But, as total expected profit by the handset and distribution subsides is a deficit, mobile service provider have to choose the open strategy and consider the conversion to MNO(mobile network operator). Under '1 subscriber-multiple handset' assumption, mobile service provider is trying to find the way how to lock-in its service and mobile phone and how to maximize ARPU(average revenue per unit), while handset manufacturer and distributor have to look for the way how to maximize the mobile phone market using their own marketing efforts, because it is expected that total mobile handset demand for the open market is bigger than demand for the closed market under '1 subscriber-multiple handset' assumption.

• ETRI Journal
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• v.28 no.5
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• pp.621-630
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• 2006

Observation of the effects of a handset subsidy on the mobile telecommunication industry has revealed two different aspects. The activation of various mobile services and the handset market, has led to the rapid acceleration of the related technological development, which is a desirable result, while rising prices and the overspending of related resources are undesirable. A great deal of research has been conducted to assess both desirable and undesirable factors using qualitative methods. However, quantitative studies into the effects of a handset subsidy are rare. In this study, we consider the positive and negative effects on consumer welfare of a change in demand and prices brought about by a handset subsidy. Then, we quantitatively compare the positive and negative effects and analyze their direct effects on consumer welfare.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.331-334
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• 2002

This paper discribes the differen-ces between making handset sample and handset massproductions. To save time during mass production, Calibrat-ion should be automated and SW do-wnloading also be automated and Par-allely done. All this processes are des-cribed here. Especially Calibration are more detaily explained in this paper.

• Journal of Korea Multimedia Society
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• v.8 no.12
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• pp.1649-1657
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• 2005

In this paper, a fast implementation of JPEG is discussed and its application to multimedia service is presented for mobile wireless internet. A fast JPEG player is developed based on several fast algorithms for mobile handset. In the color transformation, RCT is adopted instead of ICT for JPEG source. For the most time-consuming DCT part, the binDCT can reduce the decoding time. In upsampling and RGB conversion, the transformation from YCbCr to RGB 16 bit is made at one time. In some parts, assembly language is applied for high-speed. Also, an implementation of multimedia in mobile handset is described using MJPEG (Motion JPEG) and QCELP(Qualcomm Code Excited Linear Prediction Coding). MJPEG and QCELP are used for video and sound, which are synchronized in handset. For the play of MJPEG, the decoder is implemented as a S/W upon the MSM 5500 baseband chip using the fast JPEG decoder. For the play of QCELP, the embedded QCELP player in handset is used. The implemented multimedia player has a fast speed preserving the image quality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9A
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• pp.1005-1012
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• 2004

In this paper, we have analyzed minimum performance required for W-CDMA Handset from standard and Implemented the receiver for W -COMA Handset. We have derived the noise figure and IIP3 of receiver and determined the selectivity about adjacent channel and minimum performance for front-end stage. Before the Implementation, we have verified the performance using AOS simulator In conclusion, we have implemented the receiver for W-COMA Handset using the heterodyne architecture and performed measurement. Therefore, this paper wlll gIVe a guideline for design of the W -COMA Handset.

• Journal of Digital Convergence
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• v.12 no.7
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• pp.11-20
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• 2014

This paper finds that the ultimate source of problems facing Korean mobile telecommunications such as excessive subsidies of handsets, waste of resources, and a vicious circle of expensive handsets and high prices for services, is bundling of handset and subscription. The analysis suggests that bundling causes consumers to confuse about prices of handsets and services, and firms focus on handset subsidy competition rather than on upgrading service qualities and lowering prices due to anti-competitive effects of bundling. Because most of the cost of bundling is passed on to consumers, the welfare of consumers decline. In particular, equality among consumers worsens due to price discriminations. To resolve these problems, unbundling of handset and subscription is a necessity. Mixed bundling allowing separate selling of handsets under bundling does not seem to work as a cure because bundling tends to be a dominant strategy. The best regulatory policy is a complete separation of handset and subscription.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.6
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• pp.550-557
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• 2003

In this paper, two dualband internal antennas for GPS/PCS handset are proposed. At first, the monopole antenna with parasitic dipole element is designed to print PCB of handset directly. At second, the antenna with bended loop structure is designed to bend to use internal space of handset maximumly. The proposed dualband internal antennas provide a 2:1 VSWR bandwidth of over 19.1 % which are possible to cover two bands at once. the antennas have a gain between -0.4 and 3.33 ㏈i at all bands and they have almost omni-directional patterns.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.319-324
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• 2001

An anatomical head and a multi-layered spherical head with a half-wave handset antenna have been analysed and compared using the Finite-Difference Time-Domain (FDTD) and the Eigenfuntion Expansion Method (EEM), respectively. The analysis shows that results from a simple spherical head with a half-wave antenna can be used to predict the main antenna radiation patters as well as estimates of the peak SAR in a handset user's head. Various representative design data are presented using a six-layered spherical head with a half-wave antenna at 900 MHz

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.05a
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• pp.48-49
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• 2005

• Journal of Advanced Information Technology and Convergence
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• v.9 no.2
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• pp.99-105
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• 2019

In this paper, we describe the procedure of simulation design and measured results of a compact planar antenna for handset applications. The broad bandwidth covering the interested frequency band for mobile handset is achieved by introduction of an open ended L-shaped slot which is newly proposed and corresponds to the monopole slot. In order to minimize the impact on circuit part placement, the proposed antenna is placed on the ground plane edge of PCB with size of 60×65 mm². The measurement result for 10dB impedance bandwidths is 640 MHz (1.7~2.34 GHz), covering the required bandwidths for DCS (Digital Cellular System)-1800 (1710 ~ 1880 MHz) / IMT (International Mobile Telecommunication)-2000 (1885 ~ 2200 MHz) bands. In particular, we would like to emphasize the proposed antenna has an omnidirectional radiation pattern suitable for commercial wireless communication.