• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.10-23
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• 2009

In this paper we propose a novel mobile terminal software architecture supporting energy efficient handover operation in heterogeneous networks. Since the legacy proposals for L3 handover are mostly dependent on IETF Mobile IP which has some problems in movement detection mechanism and no considerations on nested heterogeneous network environment as a result they make serious overload on networks and terminals by performing unnecessary handover in such network environments. The proposed architecture has terminal-oriented network selection and switching architecture where a mobile terminal periodically monitors network status and selects the optimum network, and reduces energy consumption by making L3 handover of Mobile IP to the finally selected network. The network selection method first picks up some candidate networks by considering a terminal speed and power consumption estimation, and determines the final target handover network among the candidates after evaluating multiple factors including QoS required by a terminal, network status, user preference and terminal battery status. Finally we verify the functionality and performance of the energy efficient vertical handover architecture by means of adopting it into a real mobile terminal.

• Journal of Distribution Science
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• v.15 no.12
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• pp.53-60
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• 2017

Purpose - This paper analyzes the effect of the handset subsidy and the Mobile Number Portability subscriber subsidy regulation, which are the main regulation adopted in "Law on the Improvement of the Mobile Terminal Distribution System" (Mobile Terminal Distribution Act), on the social surplus, the consumer surplus and profits of telecommunications carriers. We focus our analysis on whether the service charge competition is stimulated enough so that it can compensate for the loss of subsidies. Research design, data, and methodology - We use simple economic model to assess the impact of the handset subsidy and the Mobile Number Portability subscriber subsidy regulation. Unlike the former researches on this topic, we depart from using Hotelling model, and instead use the switching cost model, which uses switching cost as a parameter of market powers of telecommunications carriers. We also study the effect of the two different regulations when they are adopted both independently and concurrently. Results - If the market powers of telecommunications carriers are over certain threshold, contrary to the regulatory agency's assertion, the service charge competition would not be stimulated enough to compensate for the deduction in the subsidies, and thus the consumer surplus is compromised. Number Portability subsidy, especially, undermines the rival's market power and thus reduces the service charge. On the other hand, the regulations will also increase the profits of telecommunications carriers. However, social surplus is maximized when both of the regulations are present because the regulations reduces the frequency of switching handsets inefficiently. Conclusions - In enacting the Mobile Terminal Distribution Act, the telecommunications regulatory agency asserted that the regulation on subsidies will stimulate service charge competition, and in the long run, enhance the consumer surplus. However, contrary to the regulatory agency's assertion, subsidy regulation, especially the regulation on Number Portability subsidy, reduces consumer surplus. On the other hand, the Mobile Terminal Distribution Act can also increase the profits of telecommunications carriers because it decreases competition among the telecommunications carriers. However, the Mobile Terminal Distribution Act can increase the social surplus because it reduces inefficient switching of handsets.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.252-254
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• 2004

This paper proposes a common platform for an internet-based mobile robot and its operator terminal. The common platform can reduce the cost and time to develop an internet-based robot and its operator terminal. The robot performs the role of a server and its terminal a client. One operator can use this terminal to make a command and this command can be sent to the robot through a wireless network. According to given commands, the robot moves a point and sends an image by using a camera or desired information by using other sensors. The information sent from the robot can help an operator to control the robot. The mobile robot consists of two modules, main module and motion module. Main module can exchange information with the operator terminal, process information, and send a command to motion module. Each application program for one internet-based mobile robot and its operator terminal will be developed to show that the same platform can be used for them. Also, it will be shown that the robot can be controlled easily by using its operator terminal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.96-103
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• 2009

This paper presents a L3 mobile terminal platform of the mobile terminal system which is a subsystem of HMm(Hig-speed Mobile Multimedia) system, which layer 3 control protocols such as RC(Radio Control), SC(Session Control), MC(Mobility Control) and application services such as VOD, FTP, VoIP for a multimedia mobile terminal are implemented on. The hardware platform is based on PXA255 and supports various interfaces and multimedia devices, and under the platform, an embedded Linux generated by the self-maden cross-toolchain, L3 control protocols and application programs were installed. The operation of HMm system under the HMm testbed has shown that this platform successfully supported SIP services, web browsing services, streaming services and etc as well as call processing. It could be the reference of the upcoming Fourth-Generation mobile terminal which the multimedia functionality will be enforced.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5A
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• pp.536-541
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• 2008

This paper proposes a mobility prediction algorithm for the effective handover among hybrid networks. The proposed algorithm is consisted of two mechanisms to predict a mobile terminal's path. First, the mobile terminal will be checking its received signal power level. Then the mobile terminal will judge its path in some network. Second, if the mobile terminal change its path suddenly, it will be dealing with this situation appropriately using the mobile terminal's speed. This paper introduces existing researches and the proposed algorithm. Finally, our algorithm is compared with existing approaches in terms of the handover delay by using the network simulator OPNet version 10.0.

• Journal of Communications and Networks
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• v.9 no.3
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• pp.254-264
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• 2007

A promising approach to improve the performance of mobile location system is the use of antenna arrays in both transmitter and receiver sides. Using advanced array signal processing techniques, such multiple-input multiple-output (MIMO) communication systems can offer more mobile location information by exploiting the spatial properties of the multipath channel. In this paper, we propose a novel approach to determine the position of mobile terminal based on estimated multipath signal parameters using only one base station in MIMO communication systems. This approach intends to minimize the error occurring from the estimation of multiple paths and gives an optimal estimation of the position of mobile terminal by simultaneously calculating a set of nonlinear location equations. This solution breaks the bottleneck of conventional mobile location systems which have to require multilateration of at least three base stations.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.4
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• pp.255-262
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• 2010

Recently, we are living in the world of information and ubiquitous technology strayed away from the fixed network systems resulting in an increase of using mobile terminals which is convenient for mobility and functionality. Because the diversification of mobile devices to communicate between disparate mobile terminals is difficult, the two kinds of operating systems and hardware for data communication between the terminals is needed to convert the data. The proposed instant messenger design in MRP-S3C2440A (Windows CE 5.0) and Nexio XP30 (Windows CE .NET 4.1) were tested and applied. Usually the mobile terminal has an information on a central server. Sender terminal receives the message according to the characteristics of the terminal after converting was sent to the receiving terminal. Receiving-side terminal without a separate conversion process, it was the output terminals. This paper deals with the proposal and implementation of designing an instant messenger application program between the two different mobile terminals and network systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.141-144
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• 2005

Contents of this paper strengthen security of data by applying encryption algorithm to use cellular phone and settlement by Mobile that is used synchronization method and quotes and prevent damage of bar-code peculation etc.. If divide system step by step to execute this, step that create Mobile bar-code and transmits by individual terminal after encryption, step displaying to individual Mobile terminal, step that above individual Mobile terminal and main server form assimilation and these are consisted of step that quote confirming above information confirmation and motive availability. For the actual example, confirm effectiveness of certification system through simulation.

• Journal of Technology Innovation
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• v.12 no.1
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• pp.189-218
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• 2004

In this paper, we estimate consumers' preferences for the key attributes of the future mobile telecommunication terminal using conjoint analysis. For statistical model, we estimate the mixed legit model which can reflect the heterogeneity of consumers' preferences, using the Bayesian approach with Gibbs sampling. The results show that there are large variations in consumers' preferences for the attributes of the future mobile telecommunication terminal, which justifies our using of mixed logit model. Also, the results show that most consumers prefer the medium size display and keyboard as input equipment. Additionally, far from general prediction, the results show that many consumers are indifferent to whether the future mobile telecommunication terminal is able to provide high quality internet service or not, and to operate many application programs and programs originally designed for PC. From those results, we can obtain some important implications for the R＆D strategies. Additionally, the results on the heterogeneity of consumers' preferences reveal that it is possible that the complete device convergence may not happen.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.811-814
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• 2007

Mobile device will be able to use the various contents from the advancement of the wireless Internet and mobile device manufacture technique. Each devices HTTP headers about under using provides terminal information to contents provider which is provided the contents which is suitable in device. But there is not a standard for a terminal information proηsion and when using the contents of service network outside, interoperability problems mobile communication it will provides terminal information in different method. International Organization for Standard OMA UAProf about under using it solved interoperability problems from outside. But about under using it provides terminal information, MMS support and Smart Card support, against an external storage space supporting information it is not seen clearly UAProf not to be, it will not be able to provide terminal information which is complete. This paper hereupon it designed UAProf in base which provides the contents which has become optimize to the mobile device of domestic environment the mobile device description language which expresses device information which is necessary.