Byung Sun Lee

A New Mechanism for Seamless Mobility Based on MPLS LSP in BcN

We propose a new mobility management scheme using Label Switched Path (LSP) of Multi Protocol Label Switching (MPLS) for seamless service in Broadband Convergence Network (BcN) in Korea, and verify that the proposed scheme has lower latency time than the existing ones through the separation of control plane from data plane for handover signaling.

Employing collective intelligence for user driven service creation

With advances in computing technologies and active user participation through smart devices such as the iPhone and Android, user needs are becoming varied and complex. It is quite natural, then, that a single Web service may not be sufficient to fully satisfy the diverse goals of users in their daily lives. A set of cohesively connected Web services/mashups may be able to deal with these goals. An increasing number of open APIs can facilitate various types of service compositions with users as the service creators. Recently, Internet, telecommunications, and third-party providers have opened their services to the public in the form of open APIs, a trend following the Web 2.0 paradigm. However, most service creation environments do not have sufficient knowledge (particularly, available services and their functionality) to support service creation by users. The problem of knowledge scarcity is that users may have difficulty in finding relevant open APIs for a given situation, finally resulting in rather straightforward types of service. In this article we present two kinds of collective intelligence for user-driven service creation: the users own experiences in service composition, and activity knowledge from the web. These collective intelligence types will aid in creating enduser service compositions by enforcing knowledge support in terms of user experiences and activity-aware functional semantics, and will finally accelerate the development of various kinds of converged applications. Using the beneficial roles of collective intelligence as key enablers of future service creation environments, this article also shows a new potential for user-driven composite services within the next few years.

IPTV Systems, Standards and Architectures: Part II - Heterogeneous Networks and Terminal-Aware QoS/QoE-Guaranteed Mobile IPTV Service

We describe two main technical challenges in terms of the network and application levels for mobile IPTV service. To support a multimedia- streaming application service over a mobile network environment, we present the IP/MPLS-based NGN architecture with fixed and mobile convergence and its challenge, which is basically to support QoS for mobile IPTV ser vice. To meet the challenges for application source levels, we focus on the relationship of user terminals and video streaming sources to support user-perceived QoE, based on high- quality service between heterogeneous terminals. The techniques to meet these challenges depend on the characteristics of media processing and terminal capabilities, such as LCD panel size, resolution, video coding, and so on, in the heterogeneous network environment. To have a relationship between the two different levels, the significant factors mentioned previously are required to deliver the bandwidth coupled with a user profile to provide QoS/QoE in assured seamless mobile IPTV service on client devices.

Open Service Platform: A Service Creation and Provisioning Environment for BcN Infrastructure

Open service platform makes the functions of telecommunication network open to external service applications through well-defined API. Under this scheme the service layer is independent from lower layers of network such as control and transport layers. So this architecture is well-suited as BcN service platform, because BcN seeks the convergence of existing diverse networks and one of its convergence areas is the service convergence. In this paper we describe our open service platform such as open service gateway and open service development tools. We also mention our approach and experience to find out new APIs and create new converged services.

High-level CHILL debugging system in cross-development environments

CHILL is a concurrent programming language, especially for implementing telecommunications software. ETRI has used the language for the development of switching software. Generally, switching software is characterized by real-time execution, parallel and distributed processing, large scale source code, and high complexity. The software is also developed on cross development environments. In this paper, we present a CHILL cross debugging system, in which the system can test and debug the programs on remote system from local system. The system provides the traditional debugging features such as executing and tracing a program, listing source code, setting breakpoints, examining and setting program locations, and single-stepping. It also provides parallel and distributed real-time debugging, a powerful command language, signal sending capability, and graphical user interface for switching software.

An Efficient Shared Adaptive Packet Loss Concealment Scheme through 1-Port Gateway System for Internet Telephony Service

In this letter, we propose a shared adaptive packet loss concealment scheme for the high quality guaranteed Internet telephony service which connects multiple users. In order to recover packet loss efficiently in the all-IP based convergence environment, we provide a robust signal recovery scheme which is based on the shared adaptive both-side information utilization. This scheme is provided according to the average magnitude variation across the frames and the pitch period replication on the 1-port gateway (G/W) system. The simulated performance demonstrates that the proposed scheme has the advantages of low processing times and high recovery rates in the all-IP based ubiquitous environment.

Integrated service creation environment for open network services

The service creation scheme is changing with the advent of open network service architecture for next-generation network. New requirements should be considered for IT domain developers to create telecom and Internet combined services more easily. This paper describes an integrated service creation environment (SCE) to reflect the trend of network evolution toward an open network environment. The SCE provides multiple service programming tools to support various users’ background, a mash-up toolkit for IT domain, a simulation-based validation tool, a run-time adaptation tool, and a personalized service provisioning environment. Several example services were implemented to verify the features of an integrated SCE. Our approach is very promising because it supports various requirements and background of service developers on the full service creation process. Furthermore, it provides a means for personalized service creation driven by end-user, which is a new trend of future network.

Voice Quality Guaranteed Service over Best-Effort IP Network for Pervasive Environments

Pervasive computing with voice application service must be providing unprecedented levels of technology in order to adapt the continually changed computing resources in ubiquitous environment. A number of conditions differ from the speech signal over IP network with heterogeneous devices while voice traffic is transported by packet-based in ubiquitous environment. In this paper, voice signals in packet loss and noise is controlled for the guaranteed quality of service (QoS) on the IP network which are responsible for digitizing, encoding, decoding, and playing out the speech signal. We implement the algorithms of packet loss concealment (PLC) and noise reduction, which is called PEA (pervasive environment adaptation)-PLC, PEA-noise reduction together, for providing high quality voice-based pervasive computing services. The proposed PEA-PLC algorithms are applied as post-processing after decoding on devices, and then PEA-noise reduction method is applied as pre-processing before speech coding. The proposed PEA-algorithms for packet loss and noise are applied in G.729A codec optimally using mobile-softphone and a 1-port gateway PSTN phone system. The performances of the proposed methods are evaluated by the PESQ measurement in various packet loss and noisy conditions

Performance of an Efficient Performing Authentication to obtain access to Public Wireless LAN with a Cache table

Currently, Wireless LAN(WLAN) service is widely deployed to provide high speed wireless Internet access through the mobile stations such as notebook and PDA. To provide enhanced security and user access control in the public WLAN area, WLAN access points should have the capability of IEEE 802.1x-based user authentication and authorization functionality. In this paper, we provide a brief understanding of IEEE 802.1x standards and related protocols like EAPOL(Extended Authentication Protocol Over LAN), EAP, RADIUS and describe how the IEEE 802.1x is designed and implemented in our embedded linux-based WLAN AP which is named i-WiNG.(Intelligent Wireless Internet Gateway). And we present an efficient authentication proxy for IEEE 802.1x systems based on the port-based access control mechanism. The proxy function of the AP is allowed to cache the supplicants user ID and password during his first transaction with the server. For the next authentication procedure of the same supplicant, the proxy function of the AP handles the authentication transactions using its cache on behalf of the authentication server. Since the main authentication server handles only the first authentication transaction of each supplicant, the processing load of the server can be reduced. Also, the authentication transaction delay experienced by a supplicant can be decreased compared with the conventional IEEE 802.1x systems. Therefore, the data traffic related to the authentication that has occurred in the backbone network can be considerably reduced to improve the speed of data transmission to the user of the high speed wireless Internet service.

Speech Quality Measurement Methods with Applying PLC Algorithms on Real-time Transmission Control Scheme for VoIP Service

According to the discovery of available and suitable audiovisual services over IP, researches on the Quality of Service (QoS) for various multimedia application services are required. This paper presents evaluation of speech quality applying improved Packet Loss Concealment (PLC) algorithms with an end-to-end bidirectional transmission control scheme. We propose real-time transmission control scheme to perform better quality monitoring of VoIP service. In order to evaluate the newly proposed RTCP-XR scheme for VoIP services, we measure in real-time the quality degree of the received speech signal while applying our improved Packet Loss Concealment (PLC) algorithms in G.711 and G.729A codecs using an implemented Session Initiation Protocol (SIP)- based SoftPhone and a 1-port gateway systems. Overall, for the evaluation with scientific exactitude of speech quality applied our PLC algorithms we examine with made phone-calls through the heterogeneous network systems. The experimental results confirm the applied PLC algorithms for improvement of speech quality over IP in real environments with the QoSfactor transmission control mechanism.