• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.417-421
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• 2005

In the recent digital communication systems, the performance of Turbo Code using the error correction coding depends on the interleaver influencing the free distance determination and the recursive decoding algorithms that is executed in the turbo decoder. However, performance depends on the interleaver depth that needs many delays over the reception process. Moreover, turbo code has been known as the robust coding methods with the confidence over the fading channel. International Telecommunication Union(ITU) has recently adopted it as the standardization of the channel coding over the third generation mobile communications(IMT-2000). Therefore, in this paper, we proposed the interleaver that has the better performance than existing block interleaver, and modified turbo decoder that has the parallel concatenated structure using MAP algorithm. In the real-time voice and video service over third generation mobile communications, the performance of the proposed two methods was analyzed and compared with the existing methods by computer simulation in terms of reduced decoding delay using the variable decoding method over AWGN and fading channels for CDMA environments.

• The Journal of the Korea Contents Association
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• v.3 no.2
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• pp.78-86
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• 2003

The Minisoy of Information and Communication(MIC) requires telecompanys to share base stations in order to prevent the duplicated investment and environmental destruction which would be caused by the indiscreet construction of basestations for enlarging their own service area among telecompanys. This paper discusses' the problems of mobile communication services that have been generated in common-repeater at the Metropolitan subway. These problem include factors of power obstacles, communication equipment and establishment obstacles. The content of this paper is helpful in organizing the basestation sharing of IMT-2000 and the 4th generation mobile system, and provides the basics of a higher quality service for common-service communication.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.135-142
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• 2002

In this paper, we proposed the new structure of the Rake Finger using Walsh Switch, the shared accumulator and the pipeline FWHT algorithm for reducing the signal processing complexity resulting from the increase of the number of data correlators. The number of computational operation in the proposed data correlators is 160 additions when the number of walsh code channels is 4. As a result, it is reduced about 3.2 times other than the number of computational operation of the conventional ones. Also, the result shows that the data processing time of the proposed Rake Finger architecture is 90,496〔ns〕 and the conventional ones is 110,696〔ns〕. It is 18.3% faster than the data processing time of the conventional Rake Finger architecture.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.214-217
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• 2001

This paper presents an implementation methodology of common Rf- integrated PCS base station system which, is capable of providing PCS services for 3 PCS carriers concurrently and wireless system performance evaluation data is shown. We have built up a common PCS base station system using a commonization module, which is consisted of a multi-channel combiner, duplexer, LNA, power divider, feeder line, and a common set of antennas. It was shown that the performance of the system within the total 30MHz PCS frequency range is uniformly acceptable and measured signal quality and coverage are equivalent to that of the individual PCS base station. It is expected that PCS carriers are able to save a huge amount of installation and maintenance expenses by installing and sharing this base station system. This paper forms a groundwork for deploying efficient and economical IMT-2000 network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6A
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• pp.642-647
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• 2007

HAP(High Altitude Platform) systems have been proposed due to their unique advantages over terrestrial and satellite systems as the alternative wireless communication system to deliver the third generation IMT-2000 wireless services. It has been required to study for the power control in W-CDMA HAP system as well as the terrestrial mobile system in order to mitigate interference and increase the capacity. In this paper, a new power control has been proposed for HAP system considering the interference profile into the DB(distributed balancing) SIR(signal to interference ratio)-based algorithm which has been considered in terrestrial system, and estimated by the outage performance of the proposed DB algorithm is better remarkably than DBPA(distance-based power allocation) which is proposed for HAP system, and it is the same regardless of the antenna maximum gain and its sidelobe characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1071-1078
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• 2003

In this paper, the planar, compact, and broadband phased array antenna system for IMT-2000 applications has been investigated. Two methods far designing a low-cost and low-complex beam-farming network are proposed. First, a new compact and broadband phase shifter with continuously controlled phase bits is designed by using parallel coupled lines. Second, its equivalent phase delay line is suggested to be capable of replacing the complex phase shifter with a reference phase bit on a phased array antenna. For the purpose of achieving the broadband system, in addition to the broadband phase shifter, a wide-slot antenna with a ground reflector is utilized as an element antenna. Therefore, the phased array antenna system has achieved compact size, broad bandwidth, and wide steering angle, although it has low complexity and low fabrication cost. The 3${\times}$1 phased array antenna system has a compact size of 1.6 λ${\times}$ l.6 λ, which is the sufficient ground plane of the wide-slot antenna. Experimental results present that the S$\_$11/ has less than 15 dB within the band and its radiation patterns on an E-plane have the capability of steering an antenna beam from -29$^{\circ}$to +30$^{\circ}$.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.39-42
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• 1998

In this paper is design of signal discriminatior system for the third generation mobile telecommunication system (IMT-2000 : International mobile telecommunication service-2000) This system is basically using multiplexing method of CDMA, TDMA and FDMA that this system can be solved third generation systems problems-Frequency bandwidth, international roaming and development new architecture of mobile telecommunication systems. Designed signal discriminator system is perfectly separated three styles multiplexing method signals that more easily, nearly and economically implementation of third generation telecommunication systems. As we develop signal discriminator we will contribute to technical evolution of mobile telecommunication for third generation and stay ahead in the interior technical accumulation in addition to international intercourse as to mobile telecommunication.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.4
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• pp.67-73
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• 2002

There have been increased concerns on mobile stratospheric communication system(SCS) for the purpose of advanced service of personal and high speed communication systems. In fact, this SCS is considered and studied for IMT-2000 service by ITU. Although, it is important to make accurate channel model for prediction of the SCS performance, there is no measured channel data in this system. Thus, in this paper, we estimate the performance of SCS bye use of channel model provided by Corazza(2) and modified by You(3). And also, the effects of channel codings on system performance are analyzed by deriving bit error performance based on realistic Rician log-normal fading channel models. The performance results are divided into three kinds of areas with three kinds of elevation angles 20$^\cire$, 45$^\cire$, and 80$^\cire$. And also the effects of forward error correction channel codings on system performance with Hamming(7,4), HCH( IS,7) and convolutional code of constraint length 3 and code rate R=1/2.

• The Magazine of the IEIE
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• v.22 no.9
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• pp.42-52
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• 1995

최근 연구개발 및 표준화에 박차를 가하고 있는 Personal communication systems(PCS)의 개요 및 개발동향을 살펴보고 앞으로의 PCS 전개방향을 전망한다. 현재 여러 형태의 PCS 시스템들이 연구개발 중이며 특정기술에 의존하는 경향을 보이고 있다. 그러나 다가올 2000년대에는 이를 통합하는 표준으로서 유럽지역의 UMTS(Universal Mobile Telecommunications System)와 국제적 규모의 차세대 공중육상이롱통신 시스템인 FPLMTS/IMT-2000(Future Public Land Mobile Telecommunications System/lnternational Mobile Telecommunlcation-2000)이 확립될 것으로 보이며, 최종에는 이를 통합하는 하나의 국제표준이 형성될 것으로 본다.

• Proceedings of the KIEE Conference
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• 2000.11d
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• pp.718-720
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• 2000

Turbo Code is one of the most useful and powerful channel coding technique. It is adopted in radio transmission of IMT-2000, both CDMA2000 and W-CDMA system. The performance of this code depends on many parameters such as encoder memory size, free distance of codewords, interleaver size, number of decoding iteration, and so on. This paper describes a Multi-Stage Interleaver which is used in Turbo Codes for W-CDMA channel coding. We compare the performance of a Multi-Stage Interleaver with that of Mother Interleaver. The simulation results show that Multi-Stage Interleaver performs better than Mother Interleaver in bit error rate from $10^{-3}$ to $10^{-6}$.