• Information and Communications Magazine
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• v.24 no.8
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• pp.59-70
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• 2007

차세대 이동 통신 시스템은 다양한 응용 분야들을 지원하기 위하여 광대역을 사용한 고속 데이터 전송이 가능해야 할 것이다. 이와 같은 요구 사항을 효율적으로 대처할 수 있는 중요한 전송 방식중의 하나가 OFDM (Orthogonal frequency division multiplexing) 기법이며, 여러 국제 표준단체에서 차세대 전송 방식의 중요 후보로써 채택하여 심도깊은 연구가 진행되고 있는 실정이다. 본 고에서는 OFDM 전송 방식의 기본적인 특징을 살펴보고, OFDM 시스템 상에서 동기 획득 (Synchronization) 및 채널 추정 (Channel estimation)을 위하여 사용될 수 있는 기본적인 알고리즘들에 대하여 간략히 소개하고 그 특징을 살펴본다.

• The KIPS Transactions:PartC
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• v.12C no.1 s.97
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• pp.53-62
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• 2005

The NG-SDH system requires signal synchronization to synchronize incoming ethernet signal with GFP frame. The foreign nation research completes a chipset development until now and it secures a relation technique, but it does not secure a relation technique from domestic. Therefore, in this paper, we presented with signal synchronization method of Ethernet signal through GFP frame. We knew that the synchronized method of Ethernet signal through GFP-F must apply ingress & egress buffer and GFP Idle. We understood that the synchronized method of Ethernet signal through GFP-T must apply GFP Idle and $65B{\_}PAD$, and require maximum 3-bit addition & deletion of idle. Also we showed signal synchronization realization through simulation and obtained MTIE/TDEV characteristics and peak to peak jitter in egress output.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.705-707
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• 2014

The vehicle network such as CAN, MOST, Ethernet has different protocols. In the case of Ethernet data, when data is transmitted from Ethernet to MOST150, it cannot be treated by Ethernet channel of MOST150, leading to data loss and transmission delays. Thus, this thesis proposes vehicle integration GATEWAY, which can form a network by organically connecting the Ethernet and MOST150 networks and minimize the delay and data losses caused by the differences in bandwidth.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.196-203
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• 1999

In this paper, the DS(direct sequence)-CDMA and MC(multi-carrier)-CDMA, which are being researched recently as a synchronous IMT-2000 scheme for next-generation mobile multimedia communications, are studied in terms of BER(bit error rate) performance. The BER performance of MC-CDMA with EGB, MRC, and improved MMSEC detection scheme are analyzed and compared to that of conventional DS-CDMA adopting RAKE receiver through the computer simulations under the environments of synchronous IMT-2000 transmission channel. Not only single user case but also multiuser case is considered in the given system. As a result, it is shown that MC-CDMA with MMSEC detection outperforms all other schemes improved the $E_b/N_o$ by about 5 [dB] and 6 [dB] when the BER is $2{\times}10^{-3}$, for the indoor/outdoor fading channel and synchronous IMT-2000 transmission channel, respectively. Also in the multiuser case, MC-CDMA with MMSEC detection scheme exhibits better performance than all the other schemes.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.303-310
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• 2006

This paper is to execute a study for characteristic analysis of synchronization clock and maximum network node number with various clock states, normal, SPT, LPT, in NG-SDH networks. Through the simulations, maximum network node numbers showed from 42 to 38 nodes in normal state. In SPT state, maximum network node numbers, when the last NE network applied to only SPT state, presented from 19 to 4 nodes, much less than normal state. Node numbers to meet specification in case of occurrence of SPT state in all NE networks decreased greatly. In LPT state, all maximum node numbers, when the last NE network applied to only LPT state, presented more than 50 nodes, and the results in case of occurrence of LPT state in all NE networks were also identified. However, node numbers to meet specification in case of LPT state in all DOTS networks were few large with difference between LPT and normal or SPT state.

• The KIPS Transactions:PartC
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• v.16C no.5
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• pp.637-644
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• 2009

A study about performance analysis of synchronization clock using measured clock noises is required. Therefore this paper executed the study for performance analysis of synchronization clock and acquirement of maximum number of network node with various clock states using measured clock noises in NG-SDH networks. Also this paper generated a suitable clock model using measured clock noises, and carried out simulations with various clock states. Through the simulation results, maximum numbers were 80 or more network nodes in normal state, and were below 37 nodes in short-term phase transient(SPT) state, and were 50 or more in long-term phase transient(LPT) state. Accordingly this study showed that maximum numbers to meet ITU-T specification were below 37 network nodes in three clock states. Also this study showed that when SPT or LPT states occur from NE network before DOTS system, synchronization source must change with other stable synchronization source of normal state.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.02a
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• pp.99-102
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• 2008

차세대 이동 통신 서비스 4G는 이동 중 100Mbps, 정지 중 1Gbps급 전송 속도를 제공하는 미래 무선 통신 기술이다. 이것은 현재 상용서비스가 이뤄지고 있는 3G HSDPA(High Speed Packet Access)의 전송속도 14Mbps에 비해 10~100배까지 빠른 속도로 무선 인터넷이 가능함으로 유선으로 인터넷을 사용할 필요가 없어진다. 현재 4G 기술로 진화하기 위한 중간 단계로써 ITU-R, 3GPP, 3GPP2, IEEE 등 세계 각국의 표준 및 기술 단체에서 새로운 무선 이동 통신 기술을 제안하고 있다. 이 중에서 2G의 GSM과 3G의 비동기식 기술 WCDMA의 진화 기술인 3GPP LTE(Long Term Evolution) 및 SAE(System Architecture Evolution)가 유력한 4G 이동 통신 기술 후보로 평가 받고 있다. 본 논문에서는 4G 기술로 주목 받고 있는 3GPP LTE 및 SAE 네트워크에서 3G 시스템 보다 진화된 서비스를 제공하기 위한 목적으로 논의되고 있는 일반적인 요구사항과 이를 만족시키기 위한 기술에 대하여 알아본다. 또한 LTE 표준화와 병행하여 네트워크의 구조를 결정하는 SAE의 구성요소와 프로토콜 구조를 소개하고 LTE 및 SAE 네트워크의 보안위협과 안전한 통신을 위한 키 관리 방법에 대하여 논의한다.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.642-647
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• 2009

We proposed the method of avionics integrated architecture using high-speed fiber optic bus. Typically, data bus of aircraft consists of electronic and optic data transmission method. Avionics systems are difficult to operate the electronic data transmission method for the high speed data processing, synchronization and interconnection between flight control system and flight management system efficiently. In this paper, it is known to look into the problem of data bus and the advanced trend in avionics systems, and propose the appropriate data bus of the advanced avionics systems.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.171-177
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• 2009

Optical packet switching(OPS) is a strong candidate for the next-generation internet, since it has a fine switching granularity at the packet level for providing flexible bandwidth, and provides seamless integration between WDM layer and IP layer. Optical packet switching have been studied in two categories: OPS in synchronous and OPS in asynchronous networks. In this article we are focused on contention resolution of OPS in asynchronous networks. The hybrid buffer have been addressed, to reduce packet loss further as one of the alternative buffer structures for contention resolution of asynchronous and variable length packets, which consists of the FDL buffer and the electronic buffer. The OPS design issue for the limited number of TWCs and internal wavelengths is important in the aspect of switch cost and resource efficiency. Therefore, an hybrid buffer structured optical packet switch and its scheduling algorithm is presented for considering the limited number of TWCs and internal wavelengths, for contention resolution of asynchronous and variable length packets. The proposed algorithm could lead to the packet loss improvement compared to the legacy LAUC-VF algorithm with only the FDL buffer.