• Title/Summary/Keyword: 협력 다이버시티

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협력 다이버시티 기술

  • Kim, Jung-Bin;Kim, Dong-U
    • Information and Communications Magazine
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    • v.25 no.5
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    • pp.38-46
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    • 2008
  • 협력 다이버시티 기술은 최근 수년간 MIMO(Multiple-Input-Multiple-Output) 기술의 실질적인 대안으로, 애드 혹 네트워크에서의 MIMO 기술로, 셀룰러 시스템에서의 커버리지 확장 기술로 주목을 받아 왔다. 따라서, 협력 다이버시티 기술은 응용 목표에 따라 방식이 다르게 존재하게 된다. 이 논문에서는 기존의 협력 다이버시티 기술들을 몇 가지 일관된 기준으로 분류하여 보고, 이 분야에서 미진한 연구방향으로 다중사용자 환경에서의 협력 다이버시티 기술과 다중 안테나 노드를 위한 협력 다이버시티 기술을 제시한다.

Cooperative Diversity using Cyclic Delay for OFDM systems (OFDM 시스템을 위한 순환 지연을 사용하는 협력 다이버시티 기법)

  • Lee, Dong-Woo;Jung, Young-Seok;Lee, Jae-Hong
    • Journal of Broadcast Engineering
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    • v.13 no.2
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    • pp.172-178
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    • 2008
  • Orthogonal Frequency Division Multiplexing (OFDM) is one of the most promising technologies for high data rate wireless communications. OFDM has been adopted in wireless standards such as digital audio/video broadcasting. The combination of OFDM and cooperative diversity techniques can provide the diversity gain and/or increased capacity. In this paper, the cooperative coding using cyclic delay diversity (CDD) for multiuser OFDM systems is introduced. To improve the beneficial effects of relays's cooperation, CDD is adopted in cooperative transmission of relays. Simulation results show the bit error rate (BER) for various consideration. The proposed scheme provides improved performance compared to delay.

Space-Time Diversity Relaying Strategy using Cooperative Communication Technique (협력 통신 기법을 이용한 시공간 다이버시티 중계 전략)

  • Kim, Eun-Ki;Park, Noe-Yoon;Lee, Kwan-Seob;Kim, Young-Ju
    • The Journal of the Korea Contents Association
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    • v.9 no.4
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    • pp.65-71
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    • 2009
  • In this paper a new space-time diversity relaying strategy using cooperative communication technique is proposed. More than one relaying terminals are included in one cooperative group to share their state information, such as frame error rate and channel state information. The best terminals are selected to send bit information using space-time diversity relay system. An implementation for the proposed scheme is also presented using the TDMA cooperative protocol. The resulting receive signal to transmit signal ratio and computer simulation demonstrate that the proposed strategy outperforms the conventional cooperative system.

Performance Analysis of 1-2-1 Cooperative Protocol in Wireless Sensor Networks (무선 센서 네트워크에서 1-2-1 협력 프로토콜에 관한 연구)

  • Choi, Dae-Kyu;Kong, Hyung-Yun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.8 no.5
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    • pp.113-119
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    • 2008
  • Conventional 1-1-1 cooperative protocol offers path-loss gain as advantage of multi-hop and spatial diversity which is equivalent to MIMO system. This protocol is enable to get higher reliability and reduction of power consumption than those of the single-hop or multi-hop. But the 1-1-1 cooperative protocol get only the diversity order 2 and limited path-loss reduction gain because this protocol has a single cooperative relay. We propose 1-2-1 cooperative protocol using two cooperative relays R1, R2. The 1-2-1 cooperative protocol can improve path-loss reduction and increase diversity order 3. Moreover, the cooperative relay R2 attains diversity order 2. The signaling method in transmission uses DF (Decode and Forward) or DR (Decode and Reencode) and 1-2-1 DF/DR cooperative protocol are applied to clustering based wireless sensor networks (WSNs). Simulations are performed to evaluate the performance of the protocols under Rayleigh fading channel plus AWGN (Additive White Gaussian Noise).

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An Efficient Receive Diversity Combining Technique for SC-FDMA-based Cooperative Relays (SC-FDMA 기반 상호협력 릴레이를 위한 효율적인 수신 다이버시티 결합 기법)

  • Woo, Kyung-Soo;Kim, Yeong-Jun;Yoo, Hyun-Il;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.4A
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    • pp.307-314
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    • 2010
  • In this paper, a receive diversity combining technique is proposed for single-carrier frequency division multiple access (SC-FDMA)-based cooperative relay systems when discrete Fourier transform (DFT) spreading sizes for mobile station (MS) and relay station (RS) are different. The proposed technique is composed of a DFT spreading size adjustment block, a phase rotation compensation block, a channel phase compensation block, and a receive diversity combining block. The proposed technique is robust to multipath channels and can be operated with a relatively small computational complexity because receive diversity combining is performed with scalar operations in the frequency-domain. It is shown by computer simulation that the proposed receive diversity combining techniques achieve a performance gain over the conventional maximal ratio combining (MRC) techniques for SC-FDMA-based cooperative relay systems.

Development of Onesegment Receiver for Car using Cooperative Reception Diversity based on Integrated Services Digital Broad-casting Terrestrial (ISDB-T기반의 협력수신 다이버시티를 이용한 차량용 원세그 수신기 개발)

  • Yoon, Dal-Hwan;Cho, Myun-Gyun;Lin, Chi-Ho
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.48 no.12
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    • pp.66-72
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    • 2011
  • In Japan, the specification for digital terrestrial television broadcasting systems has been approved for employing a transmission scheme for ISDB-T, which can accommodate HDTV service and portable mobile reception by adapting segmentation of frequency. In this paper, we have developed 3.5 inch mobile TV according to One-Seg system and presented the results of our development. In addition, we introduce two diversity schemes to compensate the defect that signal is interrupted when the portable TV is moving fast. In order to achieve a reliable communication in One-Seg system, we introduce STD(space time diversity) which uses more than 2 antennas at TX and cooperative reception diversity which utilizes signal-exchanging between different mobile terminals. And, its performance enhancements to reception reliability of previous system are evaluated by computer simulations.

Cooperative Relaying Scheme Using Multiple Relays in Two-Way Relay Network (양방향 중계 네트워크에서 다중 중계기를 이용한 협력 중계 기법)

  • Park, Ji-Hwan;Kong, Hyung-Yun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.7
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    • pp.815-822
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    • 2010
  • Two-way relaying scheme based on relay selection can not only achieve higher rate but also get the selection diversity gain according to the number of relays. However the scheme can not achieve combining gain because it does not consider the direct link between users. In this paper, we propose, with multiple relays, opportunistic cooperative two-way relaying scheme and incremental cooperative two-way relaying scheme which can achieve both selection diversity gain and combining gain. Simulation results show that proposed scheme outperform the conventional scheme by achieving both combining gain and selection diversity gain according to the number of relays.

Design of User-Cooperation Scheme with Cyclic Coding in Wireless Network

  • Gong, Hyeong-Yun;Seol, Dong-Won;HoVanKhuong, HoVanKhuong
    • Information and Communications Magazine
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    • v.24 no.5
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    • pp.98-106
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    • 2007
  • 전송다이버시티 는 일반적으로 송신기에서 하나이상의 안테나를 필요로 한다. 그러나 많은 무선기기들은 크기나 하드웨어의 복잡도로 인해 다수의 안테나를 사용하는데 많은 제약을 가지고 있었다. 최근 들어 해외에서 활발히 연구되고 있는 협력통신이라는 전송방식은 단일 안테나를 사용하는 다수의 사용자가 있는 환경에서, 사용자간의 안테나를 공유하여 가상의 다중 안테나를 가진 송, 수신기의 성능을 제공하여 높은 전송 다이버시티를 획득 할 수 있는 기술이다. 이와 관련된 연구로 저전력 무선 센서 네트워크를 위한 순환부호를 이용한 부호화 협력통신을 소개한다.

Balanced Transmit Scheme in Decode-and-Forward Cooperative Relay Communication (Decode-and-Forward 협력 릴레이 통신에서의 Balanced 전송 기법)

  • Cho, Soo-Bum;Park, Sang-Kyu
    • Journal of Internet Computing and Services
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    • v.12 no.6
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    • pp.35-42
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    • 2011
  • Cooperative relay communication for wireless networks has been extensively studied due to its ability to mitigate fading effectively via spatial diversity. In this paper, we propose a balanced transmit scheme in cooperative relay communication with decode-and-forward DF) scheme. The proposed scheme selects the feedback bits to obtain the maximum cooperative diversity gain. The simulation results show that the proposed scheme improves the bit error rate BER) performance as compare with a conventional scheme.

Cooperative spectrum sensing scheme to obtain a diversity gain in cognitive radio networks (인지 라디오 네트워크에서 다이버시티 게인을 얻기 위한 협력 스펙트럼 센싱 기법)

  • Choi, Siyoung;Hwang, Taewon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.626-628
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    • 2012
  • In this paper, we propose a cooperative spectrum sensing scheme using the spatial diversity of secondary users (SUs). In our scheme, a SU makes an estimation whether the primary user (PU) is active or not using the signals from the other SUs. We know that the diversity order of miss detection probability increases as the number of SUs increases from the simulation result.

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