• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1411-1420
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• 2015

Lawful interception(LI) standard of telephone networks has technical limitations to lawfully intercept IMS/SIP-based mobile communication network subscriber who using Android and iPhone device. In addition, the technical standards related to legal interception of the IMS/SIP of the wireless network is insufficient compared to the systematic study of the development of a wireless network infrastructure. The architecture proposed in the standard of ETSI(European Telecommunications Standards Institute) for the seamless LI is insufficient to overcome the limitations of traditional voice-centric LI techniques. This paper proposes an IMS/SIP-based architecture to perform LI under 3G networks that focuses on mobility-supported environments with merging cellular networks and the Internet. We implemented the simulation to verify the efficiency of the proposed architecture, and the experimental results show that our method achieves higher lawful interception rate than that of existing interception methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8A
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• pp.879-888
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• 2004

In this paper, we propose a real time QoS(Quality of Service) guaranteed transmission mechanism for MPEG video traffic at the congested node in IP based networks. Recent spread of the Internet has increased the demands of a real time multimedia service of the quality, Because the type of Internet services can, however, offer the best effort delivery strategies, it is difficult to treat all the types of traffic with differential COS (Class of Service). Most of all, the hierarchical coding method of MPEG data utilizes the reference frame for the motion prediction. The loss of the reference frames makes QoS of the video traffic degraded because the reference frame bit error causes the consecutive packet loss. Therefore we have studied the real time QoS guaranteed mechanism for video traffic by analyzing the previous methods. Computer simulation results show that the proposed scheme has better performance than the previous one.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.94-98
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• 2017

In this paper, we design a transmission / receiver structure to provide additional data service based on Mobile MMT in hybrid network environment. Mobile MMT is an extended standard of MMT, the next generation multimedia transmission protocol. MMT defines technologies for efficiently transmitting multimedia and supporting various types of data transmission and bidirectional services over heterogeneous networks based on IP. The Mobile MMT further defines the extended functions to provide functions specific to the mobile network based on the existing MMT technology. In this paper, we design and propose a additional data service scenario and additional data transmission / receiver structure that can receive additional data related to contents delivered through broadcasting network and additional data such as traffic, weather, traveler information related to user information.

• The KIPS Transactions:PartB
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• v.15B no.3
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• pp.219-228
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• 2008

For real-time social networking service, mobile interaction in a usable-unified-ubiquitous (U3) web service was studied. Both as a convenient mobile HCI for real-time social networks and as indexing keys to metadata information in ubiquitous web service, the multi-lingual single-character domain names (e.g. 김.net, 이.net, 가.net, ㄱ.net, ㄴ.net, ㅎ.net, ㅏ.net, ㅔ.net, ㄱ.com, ㅎ.com) are convenient mobile interfaces when searching for social information and registering information. We introduce the sketched design goals and experience of mobile interaction in Korea, Japan and China, with the implementation of real-time social networking service as an example of U3 Web service. We also introduce the possibility of extending the application to the metadata directory service in IP-USN (IP-based Ubiquitous Sensor Network) for a unified information management in the service of social networking and sensor networking.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.673-684
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• 2008

In this paper, we propose a signaling protocol which can support QoS for multimedia applications continuously after handover of a mobile node in the network environment where IP-based wireless access networks co-exist. Since existing RSVP-based signaling protocols can cause the waste of network resources due to double reservation and do not provide fast resource reservation/release, they are not suitable for mobile networks. The proposed QoS signaling protocol can support QoS for multimedia applications using the fast reservation of necessary resources after handover and avoid the waste of resources by resolving the double reservation problem. This paper presents design and implementation architectures of the proposed signaling protocol and analyzes its performance via a physical testbed. Based on the analysis results, it was shown that the proposed protocol is able to support seamless QoS for multimedia applications.

• Journal of the Korea Society of Computer and Information
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• v.10 no.5 s.37
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• pp.199-208
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• 2005

In this thesis, we have proposed an extended resource management mechanism that optimizes the QoS of multimedia service by complementing the existing resource management mechanism used in IP networks. The proposed resource management mechanism is composed of traffic Scheduler which was designed based on statistic analysis of the distribution of user traffic occurrence, Traffic Monitor Unit, Bandwidth Allocation Unit, queue Controller, and Traffic Classifier In order to confirm the validity of the proposed resource management mechanism, its performance was analyzed by using computer simulation. As a result of performance analysis, its availability was proved.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.137-140
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• 2001

In this paper, we propose a multicast routing scheme for an efficient and reliable support of multicast service to mobile hosts in IPv6 based networks. The purpose of this paper is to develop an algorithm to reduce both the number of multicast tree reconstruction and the multicast service disrupt time using the RSVP scheme. The proposed multicast routing scheme is a hybrid method using the advantages of the hi-directional tunneling and the remote subscription proposed by the IETF Mobile IP working group. The proposed scheme satisfies the maximum tolerable transfer delay time and supports the maximum tunneling service. The simulation results show that the proposed scheme has better performance in the number of multicast tree reconstruction and the time of multicast service disrupt than the previous schemes does.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1245-1253
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• 2009

Since 2000, the demand for multimedia content consumption has been continuously increasing. The research and standardization for the mobile broadcast service has been done to deliver multimedia contents to the huge number of users with the minimum cost. A few commercial services started after the related standards were released. We call this mobile broadcast service the 1st generation service. Now, many experts are researching and developing the technologies for 3Screens(TV, PC, and Mobile) Services that an user can enjoy multimedia contents at every place with the various networks and devices. To enable this service, two main technical areas exist. The first is a core network technology that can support the various access network and the second is a common application layer technology. To resolve these technical areas, we propose IMS(IP Multimedia Subsystem) based OMA BCAST(Open Mobile Alliance Mobile Broadcast Service Enabler Suite) as the technical solution for 3 Screen Services in the paper. In addition, we propose application layer multicast that is enable to implement IMS based OMA BCAST to the existing network with the minimum cost. Finally, we show how we can save the implementation cost of IMS based OMA BCAST with the simulation results.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.49-54
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• 2011

In this paper, End-to-End VoIP(Voice over Internet Protocol) performance over large scale MANET(Mobile Ad-hoc Networks) is evaluated. VoIP implementation model, which can be used for large scale MANET, is suggested through this evaluation. VoIP simulator based on NS-2 network simulator is used for performance measurement. Call connection ratio as a connection performance, MOS and network delay as a transmission performance, packet loss rate as other performance is measured with this simulation. Finally, maximum $10{\sim}15km^2$ as a single MANET, 500 nodes and 100 call connections is suggested for VoIP implementation and operation conditions over large scale MANETs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.628-640
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• 2004

The demand for next generation networks can be condensed into always-best-connected, ubiquitous, mobile, all-lP, and converged networks. IPv6 has been introduced for all-IP ubiquitous communications, and vehicles are coming to represent an important communication platform. In this paper. we propose various resource management schemes for in-vehicle mobile networks, which are adaptive to different hardware configurations. We focus on power and wireless bandwidth since they are critical resources for mobile communications. Based on the mobility characteristics of in-vehicle networks, we propose vehicle-aware power saving schemes. The main idea behind these power saving schemes is to adjust mobile router (MR) advertisement interval and binding lifetime. In addition, according to different wireless environments, we propose adaptive bandwidth management schemes using multihoming: best-connected MR selection based on location, and high-data-rate MR selection based on priority By mathematical analysis, it is shown that our schemes save power prominently for both the dormant nodes and active nodes. In addition, simulation results show that proposed multiple mobile router architecture outperforms previous simple redundant router architecture in preserving session and providing sufficient bandwidth.