• Title/Summary/Keyword: 결합 검출 방식

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Joint Detection Technique Effective to Other Cell Interference in the Next Generation Hybrid TD-CDMA Mobile Communication Systems (차세대 복합 시분할 부호분할 이동통신 시스템에서 타 셀 간섭에 효율적인 결합검출 기법)

  • Chang Jin-Weon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.1
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    • pp.42-48
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    • 2006
  • In this paper a joint detection method for other cell interference cancellation is proposed in the next generation hybrid TD-CDMA mobile communication systems. A joint detection technique, a most characteristic feature of hybrid TD-CDMA mobile communication systems. retrieves users' data in the same time slot simultaneously with the elimination of multiple user interference. Previously a two stage joint detection method was proposed to cancel other cell interference as well as multiple user interference in the target cell. However the previous scheme does not have concrete ways to recognize other cell users who give major interference to the target cell. Thus all users in neighbor other cells has to be jointly detected and it causes huge complexity of the two stage joint detection. In this paper a method is proposed to perform two stage joint detection according to users' interference with the target cell. Performances of the proposed scheme are investigated through simulations and compared to the previous method the proposed method has no performance degradation and also lower the complexity of two stage joint detection significantly.

Performance Analysis of Multi-channel Joint Detection for CDMA in Multi-path Fading Channel (다중경로 페이딩 채널에서의 CDMA 다중채널 결합 검출 방식의 성능 분석)

  • 황용선;이종훈;김동구
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.8A
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    • pp.1099-1106
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    • 1999
  • In this paper, the bit error ratio(BER) performance of multi-carrier CDMA system in multi-user/multi-path environment is analytically derived, and effect of interferences due to multi-user, multi-carrier, multi-path is analyzed. A multi-carrier/multi-user/multi-path joint detection scheme incorporating a decorrelating detector is proposed, and its performance as well as the enhancement of noise due to decorrelating process are analyzed. BER of the proposed joint detection scheme is only slightly degraded compared to the ideal case of single user environment.

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Enhancement of the Localized Surface Plasmon by Evanescent coupling (에바네슨트 결합에 의한 국소 표면 플라즈몬 증대 효과)

  • Lee, Taek-Sung;Kim, Won-Mok;Byun, Seok-Joo;Lee, Django;Lee, Kyeong-Seok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.80-80
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    • 2008
  • 바이오 센서 응용 연구에 많이 사용되는 금(Au) 나노 입자를 이용한 국소 표면 플라즈몬 공명(Localized Surface Plasmon Resonance, LSPR)에 의한 산란광을 검출하는데 주로 이용되는 암시야(dark field) 현미경 검출 방식에 관한 전산모사를 통하여 입사광의 입사 방식에 따른 산란광 세기를 정량적으로 분석하였다. 전산모사 기법으로는 국소 표면 플라즈몬 공명의 동역학적인 현상을 모사할 수 있는 유한차분시간영역(Finite Difference Time Domain, FDTD) 기법을 이용하였는데, 이러한 기법이 암시야 현미경 전산 모사에 유효함을 우선적으로 검증하였다. 암시야 현미경 검출 방식의 모사에서 입사 광원의 반사 입사 방식과 투과 입사 방식을 비교하였고, 각각의 방식에 서 입사광의 입사각에 따른 산랑광 세기를 계산하였다. 이러한 전산모사를 통하여 프리즘을 통한 내부 전반사(Total Internal Reflection, TIR) 방식에서 입사 광원의 임계각 근처에서 많이 발생하는 에바네슨트 장(evanescent field)을 결합하는 경우 산란광 세기가 증가함을 관찰하였고, 이러한 세기의 변화를 프레넬(Fresnel) 방정식에 의해 계산된 에바네슨트 장의 세기 분포와 비교 분석하였다.

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A Combining Scheme for Partial Incremental Redundancy based Hybrid Automatic Repeat Request in MIMO Systems (다중 안테나 시스템에서 부분 증분 리던던시 방식 Hybrid ARQ를 위한 결합 기법)

  • Park, Sang-Joon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.11
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    • pp.19-23
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    • 2010
  • In this paper, we propose a combining scheme for partial IR based hybrid ARQ in MIMO systems. The proposed combining scheme is a symbol-level combining scheme for repeatedly transmitted systematic symbols in partial IR based hybrid ARQ. In this paper, it is shown that the proposed combining scheme can also enhance the detection performance of the parity symbols that are newly transmitted in each retransmission. Simulation results show that the proposed combining scheme significantly improves the performance of the partial IR based hybrid ARQ compared to the cases of the conventional bit-level combining scheme, especially with the ZF detection.

Soft Decision Detection Method for Turbo-coded STBC Using High-order Modulation Schemes (고차원 변조 방식에서의 터보 부호화된 시공간 블록 부호 기술을 위한 최적의 연판정 검출 방법)

  • Kim, Young-Min;Kim, Soo-Young
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.6C
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    • pp.562-571
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    • 2010
  • Forward error correction (FEC) coding schemes using iterative soft decision detection (SDD) information are mandatory in most of the next generation wireless communication system, in order to combat inevitable channel imparirnents. At the same time, space-time block coding (STBC) schemes are used for the diversity gain. Therefore, SDD information has to be fed into FEC decoder. In this paper, we propose efficient SDD methods for turbo-coded STBC system using high order modulation such as QAM. We present simulation results of various SDD schemes for turbo-coded STBC systems, and show that the proposed methods can provide almost approximating performance to maximum likelihood detection with much less computational load.

Performance of LDPC with Message-Passing Channel Detector for Perpendicular Magnetic Recording Channel (수직자기기록 채널에서 LDPC를 이용한 메시지 전달 방식의 채널 검출 성능비교)

  • Park, Dong-Hyuk;Lee, Jae-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.4C
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    • pp.299-304
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    • 2008
  • For perpendicular magnetic recording channels, it is hard to expect improving the performance by using the PRML or NPML. Hence, we exploit LDPC code to improve the performance. In this paper, we examine a single message-passing detector/decoder matched to the combination of a perpendicular magnetic recording channel detector and an LDPC code decoder. We examine the performance of channel iteration with joint LDPC code on perpendicular magnetic recording channel, and simplify the complexity of the message-passing detector algorithm.

A Study on the performance improvement of Multi-Path Gain in a MMSE Detector (MMSE 검출기에서 다중경로 이득 개선에 관한 연구)

  • Yoo Dong-Kwan
    • Journal of the Korea Society of Computer and Information
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    • v.10 no.2 s.34
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    • pp.153-158
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    • 2005
  • In this paper, an improved detection method is Proposed by supplementing multi-path gain for a MMSE detecter. This method is Proposed to complement the shortcomings of the conventional detection method which is used for multiuser detection in STBC CDMA system. We analyzed the improved method in bit error Probability viewpoint and compared the result with that of the conventional method In this result, we showed that the improved method obtains better performance of bit error probability than the conventional method when parameters such as delay, number of user and SNR are increased.

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Joint Symbol Detection and Channel Estimation Methods for an OFDM System in Fading Channels (페이딩 채널환경에서 OFDM 시스템에 대한 심볼 검출 및 채널 추정 기법)

  • Cho, Jin-Woong;Kang, Cheol-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.38 no.3
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    • pp.9-18
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    • 2001
  • In this paper, we present the joint symbol detection and channel estimation for an orthogonal frequency division multiplexing (OFDM) system in fading channels. The proposed methods are based on decision-directed channel estimation (DDCE) method and their symbol detection is achieved by using Viterbi algorithm. This Viterbi decision-directed channel estimation (VDDCE) method tracks time-varying channels and detects a maximum likelihood symbol sequence. Recursive Viterbi decision-directed channel estimation (RVDDCE) method based on VDDCE method is proposed to shorten the detecting depth. In this method, channel estimate and Viterbi processing are recursively performed every interval of training symbol. Also, average chann'el estimation (ACE) technique to reduce the effect of additive white Gaussian noise (AWGN) is applied VDDCE method and RVDDCE method. These proposed methods arc demonstrated by computer simulation.

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Optimal Soft Decision for Cooperative Spectrum Sensing in Cognitive Radio Systems (무선 인지 시스템에서 협력 스펙트럼 센싱을 위한 최적화된 연판정 방식)

  • Lee, So-Young;Kim, Jin-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.4
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    • pp.423-429
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    • 2011
  • Cooperative spectrum sensing is proposed to overcome some problem such as multipath fading and shadowing and to improve spectrum sensing performance. There are different combining methods for cooperative spectrum sensing: hard decision method and soft decision method. In this paper, we analysis the performance of cooperative spectrum sensing with distance based weight that is kind of a soft decision rule for cognitive radio(CR) systems and CR systems sense the spectrum of the licensed user by using a energy detection method. Threshold is determined in accordance with the constant false alarm rate(CFAR) algorithm for energy detection. The signal of licensed user is OFDM signal and the wireless channel between a licensed user and CR systems is modeled as Gaussian channel. From the simulation results, the cooperative spectrum sensing with distance based weight combining(DWC) and equal gain combing(EGC) methods shows higher spectrum sensing performance than single spectrum sensing does. And the detection probability performance with the DWC is higher than that with the EGC.

Improvement of IF In-Phase Combiner for Space Diversity Technique of Digital Radio Relay System (디지털 무선 전송장치의 공간 다이버시티 기술을 위한 IF 동위상 결합기의 성능 개선)

  • 서경환
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.4
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    • pp.8-17
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    • 1999
  • In this paper, a proposal for improving the performance of IF in-phase combiner is presented in view of simple hardware design and good performance for space diversity application. By adding the stable normalization circuit to the phase detector, better performances are obtained even for a severe notch depth of 30 dB. To check the validity of this proposal, various results based upon numerical simulation and laboratory test are presented here in conjunction with 64-QAM digital radio relay system.

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