• Title/Summary/Keyword: WCDMA

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An Implementation of the Simulator of Reverse Link Beamforming for the WCDMA System (WCDMA 역 방향 링크에 대한 빔포밍 시뮬레이터 구현)

  • 이재식;김종윤;장태규;김재화
    • Proceedings of the IEEK Conference
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    • pp.303-306
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    • 2002
  • 본 논문에서는 IMT-2000 WCDMA 시스템의 기지국의 수신신호에 대한 WCDMA 역방향링크 디지털 빔포밍 적용구조를 제시하고, 이의 성능을 측정하기 위한 빔포밍 시뮬레이터를 구현하였다. 실제 WCDMA 시스템에 근거해 수신 신호를 모델링하고, 기본 신호 모델을 대상으로 빔포밍과 전력제어등의 알고리즘을 적용하였다. 또한 셀네의 각 사용자들의 이동을 정의한 사용자 이동 프로파일을 구성하여 적용함으로써 실제 이동통신이 이루어지는 환경과 유사한 시뮬레이션 환경을 설정하게 되었고, 이를 통하여 빔포밍을 적용한 시스템에 대한 성능 분석의 신뢰도를 향상시켰다

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WCDMA.HSDPA '뜬다'

  • Sim, U-Seong
    • 정보화사회
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    • pp.56-57
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    • 2005
  • 유럽진영을 중심으로 이미 시장활성화에 접어든 비동기식 3G서비스인 WCDMA. 국내에서도 SK텔레콤과 KTF가 서비스하고 있지만 이런저런 이유로 투자를 미뤄오면서 두 사업자 합쳐 가입자 5000명 수준에 머물고 있다. WCDMA가 기존 EVDO 서비스 대비 장점이 미약했기 때문이다. 그러나 내년부터 상황은 달라질 전망이다. WCDMA보다 5배 이상 속도가 빠른 HSDPA가 떠오르고 있기 때문이다.

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Performance Evaluation of WCDMA with Multiple Access Interference in Mixed Service Environments (다중접속 간섭과 혼합서비스 환경에서 WCDMA 시스템의 성능분석)

  • 정연호
    • Journal of the Institute of Convergence Signal Processing
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    • v.2 no.3
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    • pp.45-49
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    • 2001
  • Wideband code division multiple access (WCDMA) is the most widely adopted third generation air interface. The physical layer of the air interface is the main discussion topic during standardization processes. This paper aims to investigate the performance of uplink WCDMA over many conceivable transmission scenarios in realistic operating conditions. The focus of the study is placed on the performance under frequency selective fading channel conditions with multiple access interference (MAI) in mixed services environments. For the investigation, a simulator has been developed and it encompasses a variety of WCDMA air interface features. The results show that the performance is greatly affected by MAI and is further aggravated with the presence of frequency selective fading, thereby necessitating a suitable compensation measure.

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Comparative Performance Analysis of Transmit Diversity Technique for WCDMA Systems (WCDMA 시스템에서 송신 다이버시티 기법의 성능 비교 분석)

  • Lee, Sang-Ho;Kim, Young-Sun;Park, Hyung-Rae
    • Journal of Advanced Navigation Technology
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    • v.7 no.2
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    • pp.191-198
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    • 2003
  • In this paper, we analyze the performance of transmit diversity techniques which are the key technologies of the third generation mobile communication systems. Transmit diversity techniques adopted on the specification of 3GPP are classified into open-loop and closed-loop methods depending on the existence of feedback data. In WCDMA systems, the DPCH signal is space-time coded to provide a mobile station with diversity. Computer simulations shall be performed to analyze and compare their performance considering the effect of mobile speed, number of path, power control, and delay of feedback with the WCDMA slot format #13 for application to WCDMA systems.

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Implementation of vehicle state monitoring system using WCDMA (WCDMA를 이용한 자동차 상태 모니터링 시스템 구현)

  • Song, Min-Seob;Baek, Sung-Hyun;Jang, Jong-Wook
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.343-346
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    • 2012
  • Today, According to it widely used that third generation mobile networks service, WCDMA module development technology and its utilization is expanding increasingly and thus to IT Convergence industries is a trend that a lot of appears. This paper, OBD-II communications to bring a vehicle information use and data to an external server transfer and it was developed that vehicle status monitoring from other external devices can be system. From the various sensors inside a vehicle using the OBD-II connector read the information, after converting the user easier to see, WCDMA module using the car status monitoring system to transfer to an external data server was implemented. Developed to test the performance of the system using virtual's state vehicle simulator, which occurs in the real car that will generate the data. It was sent to the OBD-II connector to be occurred data, vehicle status monitoring system was confirmed that Data was received without error. In addition, When this data using WCDMA transmit data to an external server the same data was confirmed that it was received without error. In the future, this technology using the OBD-II vehicle IT convergence technology can be used in a wide range.

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Efficient Multicasting Mechanism for Mobile Computing Environment (물류트랙킹 장비에 활용되는 WCDMA/GSM 이중 대역 안테나 설계 및 성능 검증)

  • Lee, Eun-Kyu;Choi, Sung-Pill;Moon, Young-Sik;Jeon, Mi-Jin;Jo, Jae-Hui;Kim, Jae-Joong;Choi, Hyung-Rim
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.896-897
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    • 2013
  • In recent years, logistics tracking Device using GSM & WCDMA to improve logistics efficiency are being extensively researched. The purpose of this paper is to examine the performance development antenna usable cargo container security transport. Antenna developed by study were optimized to match logistics environment apply to GSM & WCDMA dual frequency for monitering system. The measure of antenna have confirmation VSWR is 3:1 measured in return loss -10dB. Reliability of this antenna has been verified about GSM & WCDMA through test-operation between the south korea and Russia.

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Design of a Metamaterial Absorber for High Isolation of a WCDMA Indoor Repeater Antenna (WCDMA 댁내형 중계기 안테나의 격리도 개선을 위한 메타 구조 기반의 흡수체 설계)

  • Yoon, Na-Nae;Kim, Hyoung-Jun;Seo, Chul-Hun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.9
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    • pp.1058-1064
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    • 2012
  • In this paper, an absorber based on metamaterial is proposed to improve the isolation of conventional WCDMA indoor repeater antenna. The proposed absorber is composed of Double Split Ring Resonators(DSRRs) and Complementary Spiral(CS) structure. The proposed absorber based on metamaterial is $9.6mm{\times}9.6mm{\times}1.2mm$ and absorption is about 94 % at 2.2875 GHz. The proposed antenna, which proposed absorber is applied to conventional WCDMA indoor repeater antenna, has isolation over 85 dB. Isolation is improved more than 10 dB compared with the conventional antenna. The VSWR is lower than 2 at WCDMA band from 1.92 GHz to 2.17 GHz. The radiation patterns are $60^{\circ}{\pm}10^{\circ}$ E-plane and H-plane, respectively. And, the gain is more than 6 dBi. The volume of proposed antenna with absorber based on metamaterial is $90mm{\times}90mm{\times}44.8mm$.

Design of high-speed preamble searcher adequate for RACH preamble structure in WCDMA reverse link receiver (RACH 프리앰블 구조에 적합한 WCDMA 역방향 링크 수신기용 고속 프리앰블 탐색기의 설계)

  • 정은선;도주현;이영용;정성현;최형진
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.8A
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    • pp.898-908
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    • 2004
  • In this paper, we propose a high speed preamble searcher feasible for RACH(Random Access Channel) preamble structure in WCDMA reverse link receiver. Unlike IS-95, WCDMA system uses AISMA(Acquisition Indication Sense Multiple Access) process. Because of the time limit between RACH preamble transmission and AI(Acquisition Indicators), and the restriction on the number of RACH signatures assigned to RACH preamble, fast acquisition indication is required for efficient operation. The preamble searcher proposed in this paper is based on 2-antenna system and has adopted FHT algorithm that has the radix-2 16 point FFT structure. The acquisition speed using FHT is 64 times faster than the conventional method that correlates each signature. Based on their fast aquisition scheme, we improved the acquisition performance by calculating the correlation up to the 4096 chips of the total preamble length. The performance is analyzed by using Neyman-pearson method. The proposed algorithm has been applied for the implementation of WCDMA reverse link receiver modem successfully.

Performance Evaluation of a Pilot Interference Cancellation Scheme in a WCDMA Wireless Repeater (WCDMA 무선 중계기에서 파일럿 간섭제거 기법의 성능평가)

  • Kim, Sun-Ho;Shim, Hee-Sung;Im, Sung-Bin
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.6
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    • pp.111-117
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    • 2009
  • In the wideband code division access (WCDMA) systems, a pilot channel is used to determine WCDMA network coverage, cell identification, synchronization, timing acquisition and tracking, user-set handoff, channel estimation, and so on. A wireless repeater, which is deployed in the urban area for the WCDMA system to meet the growing demand on wireless communication services, has the possibility to receive several pilot signals from a large number of base stations, however, cannot distinguish its service base station's signal among them. This pilot interference results in frequent handoffs in the user equipment, which degrades the radio reception, transmission efficiency, quality of service, and channel capacity and increases the unwanted power consumption. In this paper, thus, we propose a pilot pollution interference cancellation scheme using one of the adaptive estimation algorithms, normalized least mean square (NLMS), which is applicable to a wireless repeater. We carried out link-level and network-level computer simulations to evaluate the performance of the proposed scheme in a wireless repeater. The simulation results verify the bit error rate (BER) improvement in the link level and the call drop probability improvement in the network level.