• Title/Summary/Keyword: Receive combining

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Performance of Receive Diversity UWB Systems with Pulse Amplitude and Position Modulation

  • Kim, Sang-Choon
    • Journal of information and communication convergence engineering
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    • v.8 no.5
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    • pp.498-501
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    • 2010
  • In this paper, we extend ultra-wideband (UWB) single input single output (SISO) systems with a hybrid pulse amplitude and position modulation (PAPM) to single input multiple output (SIMO) systems using receive antenna diversity. The performance of a rake receive diversity combining scheme for UWB SIMO systems with a PAPM is examined in a log-normal multipath fading channel and also compared with that of a time-switched transmit diversity (TSTD) multiple input single output (MISO) system. It is seen that as the number of receive antennas increases, the receive diversity combining system improves the error performance. It is shown that the TSTD UWB MISO systems offer the performance equivalent to the receive diversity combining scheme for SIMO systems.

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.

Receive Diversity for OFDM Systems with Cochannel Interference (동일 채널 간섭을 고려한 OFDM 시스템의 수신 다이버시티 기법)

  • Seo Bo-Seok
    • Journal of Broadcast Engineering
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    • v.11 no.2 s.31
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    • pp.222-228
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    • 2006
  • In this paper, we propose a receive diversity method for orthogonal frequency division multiplexing (OFDM) systems with cochannel interference. In the method, combining is done in the frequency domain by using the subcarrier based maximum ratio combining (MRC) method. For MRC, we exploit the power of cochannel interference as well as the power of channel noise. The accuracy of the power estimate of interference plus noise is enhanced by averaging the initial estimates over the correlated subchannels where the coherency between the subchannel gains comes from the limited delay spread of the channel. Simulation results show that the proposed method yields 2-3.5dB gain of signal to noise ratio compared to the conventional MRC method and less than 1 dB difference to the ideal case.

Hybrid Symbol Offset Estimation Algorithm for MIMO OFDM Systems (MIMO OFDM 시스템을 위한 하이브리드 심볼 옵셋 추정 알고리즘)

  • Jung, Hyeok-Koo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.4
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    • pp.461-469
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    • 2008
  • This paper proposes a hybrid symbol offset estimation algorithm for MIMO(Multiple Input Multiple Output) OFDM system. As MIMO OFDM systems are multiple transmitter and receiver antenna systems, apart from SISO(Single Input Single Output) system, it is possible to use several combining techniques which are used in multiple receive antenna system. In this paper, we propose hybrid symbol offset estimation algorithms using combining techniques in multiple receive antenna systems, simulate and show the performances in MIMO system environments. The proposed equal gain combining correlation algorithm has better performance 1.8 times in searching the ideal symbol offset rather than the conventional early symbol offset algorithm in severe ISI channel.

A Carrier Frequency Offset Estimation Algorithm for IEEE802.11n system (IEEE802.11n 시스템에 적용가능한 반송파 주파수 옵셋 추정 알고리즘)

  • Jung, Hyeok-Koo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.5
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    • pp.21-29
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    • 2008
  • This paper proposes a carrier frequency of set estimation algorithm for IEEE802.11n system. As IEEE802.11n is a multiple input multiple output(MIMO) system, so there are several combining techniques which are used in multiple receive antenna system. In this paper, we propose hybrid carrier frequency offset estimation algorithms using combining techniques in multiple receive antenna systems, and show that the proposed selection combining carrier frequency offset (CFO) estimation algorithm can estimate carrier frequency offset within 1/10 MSE error at SNR 10 dB in channel B and within 1/2 MSE error at SNR 10 dB in channel D rather than the conventional MIMO CFO one.

Capacity and Secrecy Rate Analysis of a Frequency-Domain Equal-Gain-Combining TR Scheme for Distributed Antenna Systems in Multi-User Multi-Path Fading Channels (다중 사용자 다중 경로 페이딩 채널에서 분산 안테나 시스템을 위한 주파수 영역 Equal-Gain-Combining TR 기법의 Capacity와 Secrecy Rate 분석)

  • Kim, Myoung-Seok;Lee, Chungyong
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.10
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    • pp.47-53
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    • 2012
  • Time-reversal (TR) precoding focuses the energy of the effective channel in time and improves receive performance of a single tap receiver. Frequency-domain equal-gain-combining (FD-EGC) TR scheme, which works in linear block precoding fashion, has better temporal focusing performance than the traditional TR. Also, the FD-EGC improves receive performance of minimum mean square error receiver with distributed antenna systems (DAS). The detailed receive performance of the FD-EGC was analyzed in our previous work. In this paper, we focused on capacity analysis of the FD-EGC in DAS. We derived a scaling law which shows how the use of multiple antenna can increase the capacity of the FD-EGC precoding compared with that of no precoding. In addition, we analyze the secrecy rate of the FD-EGC which shows how high-rate messages can be transmitted towards an intended user without being decoded by the other users from the view point of information theoretic security.

A Receive Diversity Combining Technique for SC-PDMA-based Cooperative Relays (SC-FDMA 기반 상호협력 릴레이를 위한 수신 다이버시터 결합 기법)

  • Woo, Kyung-Soo;Kim, Yeong-Jun;Yoo, Hyun-Il;Kim, Jae-Kwon;Yun, Sang-Boh;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.4A
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    • pp.302-308
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    • 2009
  • In this paper, two receive diversity combining techniques are proposed for single-carrier Sequency division multiple access (SC-FDMA)-based cooperative relay systems when DFT spreading sizes for mobile station (MS) and relay station (RS) are different. A simplified-MRC (5-MRC) technique performs diversity combining in the time domain using the estimated channel weight and initial values obtained by SC-FDMA signal detection. An interference rejection-MRC (IR-MRC) technique performs diversity combining in the frequency domain by adjusting DFT spreading size in the receiver. It is shown by computer simulation that the proposed receive diversity combining techniques achieve a significant performance gain over the conventional MRC technique with zero forcing (ZF) detector.

Alternate Time-Switched Space Frequency Block Coding Technique for Single-Carrier System (단일 반송파 시스템을 위한 교번 스위칭 공간 주파수 블록 코딩 기법)

  • Jung, Hyeok-Koo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.1
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    • pp.29-33
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    • 2014
  • This paper proposes an alternate time-switched space-frequency block coding transmission technique for single-carrier modulation with frequency domain equalization. There are two antennas in the transmitter but it still has only a baseband and RF and a switch that alternates between the antennas at every symbol timing. Alternating transmit symbols result in zeros which make maximal ratio receive combining possible in the receiver. Simulation results show that it has better performance than the traditional algorithm at the expense of one additional antenna.

A Packet Detection Algorithm for IEEE802.11n System (IEEE802.11n 시스템에 적용 가능한 패킷 검출 알고리즘)

  • Jung, Hyeok-Koo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.4C
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    • pp.330-335
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    • 2008
  • This paper proposes a packet detection algorithm for IEEE802.11n system. IEEE802.11n is a multiple input multiple output (MIMO) system and we have to consider several combining techniques which are used in multiple receive antenna system. In this paper, we propose a hybrid packet detection algorithm which combines double sliding window algorithm or delay and correlation algorithm, that is used in single input single output (SISO) system, and multiple receive antenna combining algorithms, and simulated their performances in Iin system environments and shows the results.

New Beamforming Schemes with Optimum Receive Combining for Multiuser MIMO Downlink Channels (다중사용자 다중입출력 하향링크 시스템을 위한 최적 수신 결합을 이용한 새로운 빔 형성 기법)

  • Lee, Sang-Rim;Park, Seok-Hwan;Moon, Sung-Hyun;Lee, In-Kyu
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.8
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    • pp.15-26
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    • 2011
  • In this paper, we present a new beamforming scheme for a downlink of multiuser multiple-input multipleoutput (MIMO) communication systems. Recently, a block-diagonalization (BD) algorithm has been proposed for the multiuser MIMO downlink where both a base station and each user have multiple antennas. However, the BD algorithm is not efficient when the number of supported streams per user is smaller than that of receive antennas. Since the BD method utilizes the space based on the channel matrix without considering the receive combining, the degree of freedom for beamforming cannot be fully exploited at the transmitter. In this paper, we optimize the receive beamforming vector under a zero forcing (ZF) constraint, where all inter-user interference is driven to zero. We propose an efficient algorithm to find the optimum receive vector by an iterative procedure. The proposed algorithm requires two phase values feedforward information for the receive combining vector. Also, we present another algorithm which needs only one phase value by using a decomposition of the complex general unitary matrix. Simulation results show that the proposed beamforming scheme outperforms the conventional BD algorithm in terms of error probability and obtains the diversity enhancement by utilizing the degree of freedom at the base station.