• Title/Summary/Keyword: SIC

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Spatial Multiplexing System based on Random Unitary Beamforming for MU-MIMO Broadcast Channel (다중사용자 다중송수신안테나 Broadcast 채널에서의 RUB 기반 공간다중화 시스템)

  • Park, Seong-Ho;Park, Ki-Hong;Lee, Jin-Hee;Ko, Young-Chai;Kim, Sung-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.2A
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    • pp.105-111
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    • 2010
  • Random unitary beamforming (RUB) is a very low complexity and practical transmission scheme for multiuser MIMO broadcast channel. In this paper, we propose the scheme that obtains the spatial multiplexing gain on the extension of the conventional RUB, that is, the receiver with two antennas is compared to that with one antenna in a conventional RUB, which results in the increased capacity. So, we propose the new codebook and the minimum mean square error successive interference cancellation (MMSE-SIC) receiver filter. We show the simulation result that the sum-rate of proposed system is increased.

A study on the SIC of using group separation in CDMA system (CDMA 시스템에서 그룹분리를 이용한 순차적 간섭 제거기에 관한 연구)

  • 최병구;이영철;염순진;박용완
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 1999.11a
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    • pp.130-134
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    • 1999
  • In this paper, we introduce a modified interference cancellation scheme for multiuser detection in CDMA. This detector uses successive interference canceller(SIC) and the divided received signal concepts. The active users are splits into two groups large signal power group and small signal power group- throughout ranking, matched filter, decision, regeneration. And each group is subtracted from the received signal respectively to obtain good BER performance. Each of the resulting signal is become respectively SICs input signal The computer simulation and analysis of structure demonstrate that the proposed SIC keeps the SICs BER performance, complexity and reduces SICs delay time.

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BER Performance Analysis of Groupwise Iterative- Multipath Interference Cancellation(GWI-MPIC) Algorithm for Coherent HSDPA System (동기식 HSDPA시스템의 그룹단위 반복 다중경로 간섭제거 알고리즘의 오류율 성능해석)

  • 구제길
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.3
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    • pp.231-241
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    • 2004
  • This paper drives the exact expression of bit error rate(BER) performance for groupwise iterative-multipath interference cancellation(GWI-MPIC) algorithm for cancelling multipath interference components in a coherent high-speed downlink packet access(HSDPA) system of W-CDMA downlink and the BER performance is evaluated by numerical analysis. The performance of GWI-MPIC is compared to the successive interference cancellation(SIC) algorithm for multipath components. From numerical results, the optimal average BER performance of weighting factor ${\beta}$$\_$h/ for interference cancellation is obtained at ‘${\beta}$$\_$h/=0.8’ and then this weighting factor is hereafter applied to other performance analysis. Numerical results showed that the average BER performance of GWI-MPIC algorithm is rapidly degraded at multipath L=6, but is revealed the good performance than that of SIC algorithm in terms of increasing the number of multipath. This results also indicated that the average BER performance is greatly degraded due to increasing interference power more than multicode K=8. The average BER performance of the proposed algorithm is superior to the performance of SIC algorithm about 3 ㏈ for processing gain PG=128 at multipath L=2 and Average BER=1.0${\times}$10$\^$-5/. And also, the results produced good performance in case of linear monotonic reduction of multipath fading channel gain than that of constant channel gain variation, because multipath fading channel gain which is arrived later is small.

Impact of Channel Estimation Errors on BER Performance of Single-User Decoding NOMA System

  • Chung, Kyuhyuk
    • International Journal of Internet, Broadcasting and Communication
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    • v.12 no.4
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    • pp.18-25
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    • 2020
  • In the fifth generation (5G) and beyond 5G (B5G) mobile communication, non-orthogonal multiple access (NOMA) has attracted great attention due to higher spectral efficiency and massive connectivity. We investigate the impacts of the channel estimation errors on the bit-error rate (BER) of NOMA, especially with the single-user decoding (SUD) receiver, which does not perform successive interference cancellation (SIC), in contrast to the conventional SIC NOMA scheme. First, an analytical expression of the BER for SUD NOMA with channel estimation errors is derived. Then, it is demonstrated that the BER performance degrades severely up to the power allocation less than about 20%. Additionally, we show that for the fixed power allocation of 10% in such power allocation range, the signal-to-noise (SNR) loss owing to channel estimation errors is about 5 dB. As a consequence, the channel estimation error should be considered for the design of the SUD NOMA scheme.

A Low-Complexity CLSIC-LMMSE-Based Multi-User Detection Algorithm for Coded MIMO Systems with High Order Modulation

  • Xu, Jin;Zhang, Kai
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.4
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    • pp.1954-1971
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    • 2017
  • In this work, first, a multiuser detection (MUD) algorithm based on component-level soft interference cancellation and linear minimum mean square error (CLSIC-LMMSE) is proposed, which can enhance the bit error ratio (BER) performance of the traditional SIC-LMMSE-based MUD by mitigating error propagation. Second, for non-binary low density parity check (NB-LDPC) coded high-order modulation systems, when the proposed algorithm is integrated with partial mapping, the receiver with iterative detection and decoding (IDD) achieves not only better BER performance but also significantly computational complexity reduction over the traditional SIC-LMMSE-based IDD scheme. Extrinsic information transfer chart (EXIT) analysis and numerical simulations are both used to support the conclusions.

$\beta$-SiC Formation Mechanisms in Si Melt-C-SiC System (용융 Si-C-SiC계에서 $\beta$-SiC 생성기구)

  • 서기식;박상환;송휴섭
    • Journal of the Korean Ceramic Society
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    • v.36 no.6
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    • pp.655-661
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    • 1999
  • ${\beta}$-SiC formation mechanism in Si melt-C-SiC system with varying in size of carbon source was investigated. A continuous reaction sintering process using Si melt infiltration method was adopted to control the reaction sintering time effectively. It was found that ${\beta}$-SiC formation mechanism in Si melt-C-SiC system was directly affected by the size of carbon source. In the Si melt-C-SiC system with large carbon source ${\beta}$-SiC formation mechanism could be divided into two stages depending on the reaction sintering time: in early stage of reaction sintering carbon dissolution in Si melt and precipitation of ${\beta}$-SiC was occurred preferentially and then SIC nucleation and growth was controlled by diffusion of carbon throughy the ${\beta}$-SiC layer formed on graphite particle. Furthmore a dissolution rate of graphite particles in Si melt could be accelerated by the infiltration of Si melt through basal plane of graphite crystalline.

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Influence of Electric Poling an Fracture Toughness of Ferroelectric-Ferroelastic PZT Ceramics

  • Zuokai Ke;Sunggi Baik
    • The Korean Journal of Ceramics
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    • v.1 no.4
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    • pp.197-203
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    • 1995
  • Nearly fully dense PZT samples both with tetragonal and with morphotropic phase boundary compositions were prepared by the conventional powder processing and sintering. A micro-indentation technique was used to evaluate the dependence of fracture toughness on remanent polarization, crack length and the direction of crack propagation. The result shows that the toughness increases with the remanent polarization along the poling direction and decreases in the transverse direction. The dependence of toughness on the remanent polarization is neither symmetric nor linear but rather shown to be saturated quickly with the increase in remanent polariztion. R-curve behaviors are observed in both poled and unpoled samples. Sequential SEM and XRD studies on annealed, poled, ground, fractured and etched samples show that domain switching is evident as a viable toughening mechanism but might depend upon the rate of crack propagation. Grain bridging is also observed as one of the active toughening mechanisms.

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