• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.693-701
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• 2002

In this paper, we analyze the coverage of asynchronous IMT(International Mobile Telecommunication)-2000 reverse link with a MUD(Multi-User Detector) system. The MUD system is utilized to increase the coverage of reverse link. Also we have considered a propagation loss model and an interference effect. Because it is very difficult that we have calculated the interference accurately, so a fractional cell loading factor(F) is used in this paper. We make use of a MUD efficiency($\beta$) to analyze the performance; this efficiency is presented the MAI of reduction. A simulation utilizes Hata's model, we calculated the coverage according to voice and data services. In this paper, we have assumed that the frequency of carrier has 800 MHz or 1.9 GHz, and a bandwidth is decided 3.84 MHz. We have predicted the performance of actual system by the analysis of capacity and coverage.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.3
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• pp.36-47
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• 2003

Wideband Code Division Multiple Access (WCDMA) is one of the air interface techniques proposed for the third generation (3G) mobile communication system. WCDMA was selected because it fulfills the IMT-2000 requirements for higher data rate trans mission, support of multimedia capabilities and other flexible services due to its variable bit rates and larger bandwidth, improved capacity and coverage, efficient power control and support for advanced and improved detector structures. Performance evaluation of 3G wireless network through simulation plays an important role in the design and implementation of the actual system, aiding the wireless system designer by providing them the necessary performance conformance statistics prior to implementation. In accordance with this goal, a simulator engine was developed entirely on a MATLAB platform to emulate the behaviour of the WCDMA air interface for both the uplink and downlink in a real world fading mobile environment. This paper discuss the development of the simulator along with a brief description of its functionalities and user interface. The WCDMA air interface mode focused in this paper is in accordance to the 3GPPs frequency division duplex (FDD) mode and restricted to the physical layer description. Performance results for the selected cases for the downlink, uplink, varying mobile velocity and sampling rates are also provided.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.959-966
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• 2006

This paper proposes a new concept about dual band predistortion linear power amplifier(PD LPA) using diplexer for digital cellular ($f_o$=880 MHz) and IMT-2000($f_o$=2,140 MHz) base stations. The diplexer is composed of low pass filter having defected ground structure(BGS) microstrip line and high pass filter having high-Q lumped capacitors and distributed elements. The proposed predistorter adopts a reflection type intermodulation signal generator with 3 dB hybrid coupler for good reflection characteristic. for a forward link one carrier CDMA IS-95A 1FA and WCDMA 1FA signal, the proposed dual band PD LPA shows the adjacent channel leakage ratio(ACLR) improvement about 10 dB and 9.36 dB for digital cellular and IMT-2000 band, respectively.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.268-270
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• 2005

Users using mobile terminal want to receive seamless service anywhere, anytime. In order to satisfy user's needs a communication between heterogeneous networks has to provide seamless service. Now a commercialized IMT-2000 is used with both WCDMA and CDMA together. Because asynchronous WCDMA and synchronous CDMA use different technology in their interface and traffic management, communication between the two networks can become disconnected. IP a mobile terminal swerves from the handoff area before handoff completion, packet loss and service disconnection will happened. In this paper, we propose a handoff scheme to provide seamless service, when mobile terminal moves from the WCDMA to the CDMA. And we prove that the proposed handoff scheme provide seamless service.

• Information and Communications Magazine
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• v.21 no.7
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• pp.24-36
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• 2004

지금까지 2G 이동통신 사용자들은 주로 일대일 통신을 기반으로 하는 음성통화 서비스와 단문메시지 서비스를 사용하여 왔다. 하지만 인터넷을 통한 멀티미디어 접근이 일반화되면서, 이동통신 단말을 통해 언제, 어디서나, 자신이 원하는 서비스를 받기를 원하는 사용자들의 요구가 점차적으로 높아지고 있다. 이러한 사용자의 요구를 만족시키기 위해 제안된 3G IMT-2000은 음성 서비스뿐만 아니라 인터넷을 포함한 고속데이터 서비스, 영상 서비스 등의 멀티미디어 서비스를 목표로 유럽의 WCDMA와 북미의 cdma2000이 연구, 개발되어 왔다.(중략)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.539-543
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• 2000

본 논문은 7MS320C6x01 DSP프로세서를 이용하여 원격실시간 모니터링 시스템을 설계한 연구로서 시스템구성은 성능, 규격 및 기능 둥의 조건을 수용하는 RFPM, SPM, MPM 모듈로 구성되었다. 실험 및 성능테스트는 WCDMA와 비동기 IMT-2000시스템과 연계하여 측정하였다. 측정결과 40MHz의 입력주파수에 대해 10dB 정도의 노이즈가 분포되었고 요구조건에 부합하는 통합형 원격 기지국 모니터링 운용보전에 적용하였다.

• Journal of the Korean Professional Engineers Association
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• v.42 no.4
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• pp.34-39
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• 2009

IMT-2000 service started around year of 2000 to support global roaming with high speed data rate. But 3GPP and 3GPP2 could not narrow gaps between them to make separate specification. To make it worse, economy regression delayed deployment. Starting 2007, WCDMA, standardized in 3GPP, was launched in Korea by KT and SKT. 3GPP introduced HSDPA and HSUPA as an enabler for high speed down and uplink packet service, in release5 and release5, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.839-846
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• 2007

In this paper, the first attempt to design a novel structure of dual-band feedforward linear power amplifier(FFW LPA) was presented. Up to now, primary technical difficulty has been the extension of the conventional signal canceller to the dual-band operation. Therefore, we propose the design technique of the dual-band equal group delayed carrier canceller, the dual-band equal group delayed intermodulation distortion(IMD) canceller and the dual-band FFW LPA. The operation frequency bands of the implemented dual-band FFW LPA are digital cellular($f_0=880$ MHz) and IMT-2000($f_0=2.14$ GHz) band, which are separated about 1.26 GHz. With the high power amplifier of 120 W PEP for commercial base-station application, IMD cancellation loop shows 20.45 dB and 25.04 dB loop suppression at each band of operation for 100 MHz. From the adjacent channel leakage ratio(ACLR) measurement with CDMA IS-95A 4FA and WCDMA 4FA signal, we obtained 16.52 dB improvement at the average output power of 41.5 dBm for digital cellular band, and 18.59 dB improvement at the average output power of 40 dBm for IMT-2000 band simultaneously.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.145-151
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• 2004

For wide-band spread spectrum communication systems such as IMT-2000, a digital matched filter is a key device for rapid spreading code synchronization. Although a digital matched filter can be implemented easily, large power consumption at the higher chip rate and large summation delay of longer chip length are the bottleneck of practical use. In this paper, we propose a optimized partial correlation digital matched filter structure which can be constructed of the so-called generalized hierarchical Golay sequence. a partial correlation structure can reduce the number of correlators, but enlarge the size of flip-flops. In this paper, The proposed approach focuses on efficient circuit size, power dissipation, maintaining the operating throughput. A proposed digital matched filter reduce the size of flip-flops by rounding method. and it reduces about 45 percentages of power dissipation and chip area as compared with digital matched filter which is not rounded. rounding. The proposed architecture was verified by using Xilinx FPGA.

• Electronics and Telecommunications Trends
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• v.16 no.6 s.72
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• pp.126-132
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• 2001

WCDMA 비동기 방식의 IMT-2000 규격 정립을 위해, 3GPP의 여러 실무 그룹에서 Release ’99, Release ’4 및 Release ’5에 대한 표준화가 동시에 이루어지고 있다. 본 고에서는 UTRA 프로토콜의 계층 2와 3 표준화를 담당하고 있는 3GPP TSG RAN WG 2의 규격의 표준화 현황 및 새로이 규격에 반영될 기술들에 대해 살펴본다.