• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.6
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• pp.1006-1022
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• 2010

In this paper, a cross-layer resource allocation mechanism is proposed for wireless multimedia service. In particular, a game theory based on quality of service (QoS) for multimedia users is introduced to deal with the fairness of network resource allocation in wireless networks. Moreover, the channel states of wireless users are additionally regarded under the cross-layer design in WiMAX environment. In details, the bargaining solution is adopted to discover the efficient and fair resource allocation strategy for multimedia service in considering QoS in the peak signal-to-noise ratio (PSNR) and the channel states in the carrier-to-interface ratio (CINR). The proposed mechanism is illustrated and evaluated by simulation results of transmitting video sequences in WiMAX environment.

• Korean Management Science Review
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• v.22 no.1
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• pp.67-81
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• 2005

This study aims at defining the factors affecting adoption intentions for portable Internet services based on the characteristics of individuals creating the markets and developing strategies of the service, which is expected to be the next-generation telecommunication service. For this Purpose, two types of sub-factors are defined : characteristics of individuals including demographic statistics, usage of existing services, prior cognition, adoption attitudes and service assessments : and adoption Intentions including willingness for subscription, subscription period, willingness to pay, types of usage and preferred device. The results of the study indicate that demographical statistical variables vary depending upon the levels of adoption intentions, and that users of mobile Internet services via mobile phones and wireless LANs are highly probable of being targets for the portable Internet services. Furthermore, the results demonstrate demands for enhancing recognition of the usefulness and ease of use of the services and intense marketing activities for potential users bearing innovativeness to stimulate the market of the portable Internet service. The author is confident that this study will significantly contribute to the successful market entrance of portable Internet service, and also to growth in the market.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.548-553
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• 2004

Due to the recent advance in wireless communication technology, it is now more demanding to enjoy the high quality of service in the wireless Internal. TCP, which many Internet applications depend on for the end-to-end transport service, is optimized for the wired environment. Consequently, TCP suffers from severe performance degradation in the wireless environment where the bit error rate is relatively high and the burst errors frequently take place. In this paper, we propose a Robust TCP algorithm, which can effectively react against the burst error and significantly improve the TCP performance in wireless Internet. It is shown through the simulations that the Robust TCP performs well in the wireless environment, especially under the burst error condition.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2118-2135
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• 2012

With the rapid development of heterogeneous emerging wireless technologies and numerous types of mobile devices, the need to support robust mobile video streaming based on the seamless handover in Future Internet is growing. To support the seamless handover, several IP-based mobility management protocols such as Mobile IPv6 (MIPv6), fast handover for the MIPv6 (FMIPv6), Hierarchical MIPv6 (HMIPv6) and Proxy Mobile IPv6 (PMIPv6) were developed. However, MIPv6 depreciates the Quality-of-Service (QoS) and FMIPv6 is not robust for the video services in heterogeneous emerging wireless networks when the Mobile Node (MN) may move to another visited network in contrast with its anticipation. In Future Internet, the possibility of mobile video service failure is more increased because mobile users consisting of multiple wireless network interfaces (WNICs) can frequently change the access networks according to their mobility in heterogeneous wireless access networks such as 3Generation (3G), Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMax) and Bluetooth co-existed. And in this environment, seamless mobility is coupled according to user preferences, enabling mobile users to be "Always Best Connected" (ABC) so that Quality of Experience is optimised and maintained. Even though HMIPv6 and PMIPv6 are proposed for the location management, handover latency enhancement, they still have limit of local mobility region. In this paper, we propose a robust mobile video streaming in Heterogeneous Emerging Wireless Systems. In the proposed scheme, the MN selects the best-according to an appropriate metric-wireless technology for a robust video streaming service among all wireless technologies by reducing the handover latency and initiation time when handover may fail. Through performance evaluation, we show that our scheme provides more robust mechanism than other schemes.

• 전자공학회논문지 IE
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• v.47 no.4
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• pp.48-52
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• 2010

Recently, WiBro service as a mobile internet has been being extended. The market of wireless data communication has been being extended rapidly due to the increase of mobile data communication service supply such as smart-phone, WiBro service and so on. As the result, security is also emphasized in the mobile Internet In this paper, we propose the methods that tighten up security in the upcoming Enterprise Mobile-VPN service on WiBro network.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2762-2767
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• 2011

With increasing use of wireless mobile devices like smartphone and tablet PC, telecommunication companies have been providing the internet service by installing a multitude of access points (AP) in subway stations. Most of these APs use frequency of 2.4 GHz band range and the three telecom providers (SKT, KT, LGT) are using the limited channels within this range without any regulations. The channels within 2.4GHz band are already saturated as the companies are setting up wireless AP even within the subway trains for better service. This can affect other 2.4GHz wireless devices used for other purposes with channel interference, etc. This study has tested and analyzed the effects of the wireless APs installed within the subway stations and trains for the internet service on ZigBee-based sensor network for the intelligent surveillance system of urban transit, which is currently being developed and installed.

• Journal of Korea Multimedia Society
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• v.7 no.2
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• pp.187-193
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• 2004

Wireless networks play a very important role in communications today. For example, wireless networks today provide from the basic services like e-mail and FTP to the multimedia applications like Web service. It is obvious that QoS requirements to these diverse applications over wireless networks will continue as in wired networks. Much research has been done to develop QoS supporting algorithms on Internet. But due to the limited bandwidth and varying channel states of the wireless networks, it is difficult to support differentiated service over wireless networks. In this paper we propose the modified wireless token ring protocol supporting QoS to the real-time traffic service node over Internet environments in which non-real-time and real-time traffic service nodes coexist. In the proposed algorithm, the real-time traffic service node gets the priority to take token over the non-real-time traffic service node. So the proposed algorithm support quick transmission of the real-time traffic service node. And this advantage can be obtained with minor modification of the legacy wireless token ing protocol to support QoS. We also consider the lost token recovery mechanism.

• Proceedings of the IEEK Conference
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• summer
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• pp.57-60
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• 2004

Next generation wireless network is evolving toward IP-based network that can various provide multimedia services. A challenge in wireless mobile Internet is support of quality of service over wireless access networks. DiffServ architecture is proposed for evolving wireless mobile Internet. In this paper we propose an algorithm for optimal buffer partitioning which requires the minimal channel capacity to satisfy the QoS requirements of input traffic. We used a partitioned buffer with size B to serve a layered traffic at each DiffServ router. We consider a traffic model with a single source generates traffic having J $(J\geq2)$ quality of service (QoS) classes. QoS in this case is described by loss probability $\varepsilon_j$. for QoS class j. Traffic is admitted or rejected based on the buffer occupancy and its service class. Traffic is generated by heterogeneous Markov-modulated fluid source (MMFS).

• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.551-562
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• 2002

We usually applied PPP CHAP when the visited ISP subscriber accesses to authentication server in own home ISP network and IP Assignment for remote Internet service. But PPP CHAP doesn't support in case of visited ISP subscriber in GPRS network accesses to authentication sorrel in own home ISP network for wireless Internet service. We suggest solution for this problem with PPP CHAP improvement. For this we propose the modified PPP CHAP message format, PCO Message format at MT, and interworking message and format between GGSN and RADIUS in home ISP network for wireless internet service of mobile ISP subscriber at GPRS network in this paper. We also show authentication results when visited mobile ISP subscriber via PPP CHAP at GPRS network accesses the RADIUS server in home ISP network.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.587-596
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• 2008

For Wireless internet service in Metropolitan area, optimum location selection for base station and cell planning are critical process in determining service coverage by accurate prediction of Wave Propagation Characteristics. Due to different kinds of characteristics in service area such as lay of land, natural feature and material, height and width of artificially made building, it has a great impact on the transmission and distance recovery of wireless network service. Therefore, these facts may cause substantial barriers in predicting & analyzing the expected level of service quality and providing it to subscribers. In this thesis, we have simulated the process to improve quality and coverage of the service by adjusting the location of Base station and the antenna angle that influence the service after the basic location of base station is selected according to the wave prediction model. Based on this simulations test, we have demonstrated the results in which subscribers would get higher quality of wireless internet service along with bigger coverage and the improved quality in the same service coverage area through optimization process of base station.