• 대한전자공학회논문지TC
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• 제41권11호
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• pp.39-45
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• 2004

본 논문은 차세대 망을 위한 주소분석 알고리즘을 제안한다. 즉, 차세대 망에서의 공중 전화망 번호체계 및 ATM 망 번호 체계를 수용할 수 있는 통합망 주소분석 메커니즘을 제안한다. 본 논문에서 제안하는 통합망 주소분석 메커니즘은 시스템 및 망 운용 중 대규모 정보의 변화에도 능동적이고, 융통성 있게 대응할 수 있는 주소분석 소프트웨어 구현이 목적이다. 이를 위해 주소분석 데이터베이스의 구조를 설계하고 주소분석 알고리즘을 기술하였다. 제안되는 관계형 모델 데이터베이스 구조는 복잡한 망의 주소 정보를 효율적으로 관리할 수 있도록 하는 효과를 갖는다. 또한 제안하는 메커니즘을 검증하기 위하여 실제 환경에 적용하여 연동 시험을 통해 우수성을 입증하였다.

• Journal of Ubiquitous Convergence Technology
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• 제1권1호
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• pp.23-27
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• 2007

Fruition for a diverse uIT(Ubiquitous Information Technology) service is currently required through the convergence of what is known as ubiquitous computing technology. In recent years, with the rapid growth of the need for information services, heavier demands have been made upon the supply of high-quality multimedia services that require a high bandwidth. Today, various home network solutions have been proposed to manage these service smoothly and a system able to deal with various types of network traffic without delays. In addition, in established home network environments that mix wired and wireless networks, along with the steady evolution of wireless network technology and the earnest development of ubiquitous computing technology, sensor-based wireless networks have emerged as a core solution for home networks. In this paper, a sensor network-based home control system supporting the next generation home gateway system for ubiquitous home environments is designed and implemented.

• Journal of Communications and Networks
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• 제4권4호
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• pp.336-343
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• 2002

A major challenge for next generation mobile communication is capturing the system architecture’s complexity with all its internal and external dependencies. Seamless integration of heterogeneous environments in all system parts is a key requirement. Moreover, future systems have to consider the different evolution cycles of individual system parts. Among those, services are expected to change the fastest. With respect to these considerations, we propose an overall architecture for next generation mobile communication systems. It covers all system parts from wireless transmission to applications including network and middleware platform. Our approach focuses on adaptability in terms of recon- figurability and programmability to support unanticipated system evolution. Therefore, we consider abstraction layers which consist of adaptable cooperating components grouped by open platforms rather than rigid system layers. In addition to that, we introduce cross-layer cooperation allowing an efficient use of the available resources. Specific scenarios illustrate the feasibility of our approach.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.305-321
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• 2012

Since Internet Protocol (IP) is the most important protocol in Next Generation Networks (NGNs), 3rd Generation Partnership Project (3GPP) utilizes Session Initial Protocol (SIP) based on IP as the base protocol for negotiating sessions in IP Multimedia Subsystem (IMS). Different from traditional circuit-switched network, in IMS, the media traffic and signaling are delivered through IP transport. The media traffic may affect the signaling efficiency in core network, due to traffic collisions and best effort packets delivery. This paper proposes a novel path-migration mechanism for enhancing the traffic efficiency in integrated NGN-IMS. The simulation results show that the interference and traffic collision can be reduce by applying proposed path-migration mechanism and the signaling efficiency in core network can be improved with higher system capability and voice quality.

• International Journal of Internet, Broadcasting and Communication
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• 제13권2호
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• pp.43-51
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• 2021

As the number of mobile devices has been increasing tremendously, system capacity should be enlarged in future next generation communication, such as the fifth-generation (5G) and beyond 5G (B5G) mobile networks. For such future networks, non-orthogonal multiple access (NOMA) has been considered as promising multiple access technology. In this paper, to reduce both latency and complexity in existing NOMA, we propose non-successive interference cancellation (SIC) NOMA with asymmetric binary pulse amplitude modulation (2PAM), nearly without bit-error rate (BER) loss. First, we derive the closed form of BER expressions for non-SIC NOMA with asymmetric 2PAM, especially under Rayleigh fading channels. Then, it is shown that the BER performance of the stronger channel user who is supposed to perform SIC in conventional NOMA can be nearly achieved by the proposed non-SIC NOMA with asymmetric 2PAM, especially without SIC. Furthermore, we also show that the BER performance of the weaker channel user in conventional NOMA can be more closely achieved by the proposed non-SIC NOMA with asymmetric 2PAM. These BERs are shown to be achieved over the part of the power allocation range, which is consistent with the NOMA principle of user fairness. As a result, the non-SIC NOMA scheme with asymmetric 2PAM could be considered as a promising NOMA scheme toward next generation communication.

• Journal of Communications and Networks
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• 제4권4호
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• pp.351-362
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• 2002

In this paper, we introduce a new approach to the minimum energy routing (MER) for next generation (NG) multihop wireless networks. We remove the widely used assumption of deterministic, distance-based channel model is removed, and analyze the potentials of MER within the context of the realistic channel model, accounting for shadowing and fading. Rather than adopting the conventional unrealistic assumption of perfect power control in a distributed multihop environment, we propose to exploit inherent spatial diversity of mobile terminals (MT) in NG multihop networks and to combat fading using transmit diversity. We propose the cooperation among MTs, whereby couples of MTs cooperate with each other in order to transmit the signal using two MTs as two transmit antennas. We provide the analytical framework for the performance analysis of this scheme in terms of the feasibility and achievable transmit power reduction. Our simulation result indicate that significant gains can be achieved in terms of the reduction of total transmit power and extension of network lifetime. These gains are in the range of 20-100% for the total transmit power, and 25-90% for the network lifetime, depending on the desired error probability. We show that our analytical results provide excellent match with our simulation results. The messaging load generated by our scheme is moderate, and can be further optimized. Our approach opens the way to a new family of channel-aware routing schemes for multihopNG wireless networks in fading channels. It is particularly suitable for delivering multicast/ geocast services in these networks.

• 한국시뮬레이션학회논문지
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• 제11권1호
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• pp.45-58
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• 2002

In the wireless communication systems of the next generation, the hard handover may frequent]y occur between the existing 2G(2nd generation) and the 3(1(3rd generation). When it occurs between the 2G and the 3G, the call setup procedure will be added to MT(Mobile Terminal), the relay bases in 2G and 3G, and the switches. It causes total time to handle the hangover to increase. Therefore, the forced termination probability may be increased since relative time decreases. In this paper, we propose a method to decrease the forced termination. The method execute the handover procedure with speed and direction of the MT preestimated in the inner cell when MT enters the boundary cell.

• 인터넷정보학회논문지
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• 제7권5호
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• pp.43-57
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• 2006

차세대 이동통신 시스템은 유 무선 네트워크의 통합과 더불어 이동성 및 고속 데이터 전송을 제공하는 형태로 진화할 전망이다. 따라서 이러한 상황에서 다양한 서비스를 제공하기 위해 이기종 무선망에 대한 연동 서비스에 대한 연구가 필요하다. 지금까지 연동망 구조에 대한 연구로서 하나의 핵심망을 기준으로 핵심망에서 네트워크들을 제어하는 형태의 연동망 구조가 연구되었고, 핵심망에서 서비스 통합 관리가 이루어져 다양한 서비스를 제공하게 된다. 하지만 핵심망에서 모든 이동성을 관리하기 때문에 네트워크 간 이동을 위한 버티컬 핸드오프 시에 핸드오프의 지연이 발생하며, 이전 통신한 네트워크로의 패킷은 손실된다. 이러한 문제를 해결하기 위해 본 논문에서는 CDMA2000, WiBro 및 WLAN 네트워크에 대해 그 특성에 따라 연동망 구조를 계층적인 구조로서 제안한다. 따라서 각 네트워크의 범위 특성에 따라 오버레이 구조로 구성되어 있으므로 핸드오프 지연 및 패킷 손실을 최소화 할 수 있다. 또한 제안된 연동망 구조상에서 동작하기 위한 핵심 기술로서 독립적으로 표준화된 프로토콜들을 적용하여 차세대 이동통신 시스템에 대한 연동 서비스의 프레임워크를 제시한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.744-747
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• 2008

Sensor networks will play an important role in the next generation pervasive computing. But its characteristic of wireless communication brings a peat challenge to the security measures used in the communication protocols. These measures are different from conventional security methods. In this paper, we proposed a security architecture for self-organizing mobile wireless sensor networks. It can prevent most of attacks based on intrusion detection.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.336-339
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• 2008

Convergence services are very important to mobile operators in next generation mobile networks. However, mobile operators cannot deal with all convergence services because there are numerous convergence services. Thus, they should select and develop main technologies to provide convergence services which are areas to grow our business. In this paper, we introduce basic technologies to provide convergence services and then present some evaluation models to select an important area and technology.