• Title, Summary, Keyword: Cell synchronization

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A Synchronization & Cell Searching Technique for OFDM-based Cellular Systems (OFDM 기반의 셀룰러 시스템을 위한 동기화 및 셀 탐색 기법)

  • Kim Kwang-Soon;Kim Sung-Woong;Chang Kyung-Hi;Cho Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.1A
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    • pp.65-76
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    • 2004
  • In this paper, a novel preamble structure, including a synchronization preamble and a cell search preamble, is proposed for OFDM-based cellular systems. An efficient algorithm for downlink synchronization and cell searching using the preamble is also proposed. The synchronization process includes the initial symbol timing estimation using continuously, or at least, periodically transmitted downlink signal, frame synchronization, the fine symbol timing estimation, and the frequency offset estimation using the synchronization preamble, and the cell identification using the cell searching preamble. Performance of each synchronization and cell searching step is analyzed and the analytic results including the overall performance of the synchronization and cell searching are verified by computer simulation. It is shown that the proposed preamble with the corresponding synchronization and cell searching algorithm can provide very robust synchronization and cell searching capability even in bad cellular environments.

CELL SEARCH AND PERFORMANCE ANALYSIS OF W-CDMA SYSTEM IN REALISTIC MULTIPATH CHANNEL ENVIRONMENTS (광대역 다중경로 채널환경에서 W-CDMA 시스템의 셀 탐색과 성능분석)

  • 박대식;김병학;우연식;김철성
    • Proceedings of the IEEK Conference
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    • pp.591-594
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    • 2001
  • In the W-CDMA system, cell search is one of the imporant functions of the mobile station searching for a cell and achieving spreading code and time synchronization to its downlink scrembling code. For the methods of cell search to optimize codes, three stages are considered: 1) slot synchronization, 2) frame synchronization, and 3) scrambling code identification. Channels for cell search are Primary Synchronization Channel (P-SCH), Secondary Synchronization Channel(S-SCH), and Common Pilot Channel (CPICH). In this paper, cell search is analyzed based on simulation. Rake receiver provides improvement of Performance as an increase of bandwidth because there are more available multipaths. In this paper, the performance of W-CDMA system employing RAKE receiver is evaluated by computer simulation over the types of ITU_R wideband channel model and spreading rate. The result shows that the performance of CDMA adapting RAKE receiver is improved by the increase of multipath components in equal level of the received power.

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Synchronization of Cell Cycle in Korean Hydrogen Producing Cyanobacterial Strains (한국산 수소생산 남세균 종주들의 세포주기 동조화)

  • Park, Jong-Woo;Ahn, Se-Hee;Kim, Hyung-Seop;Yih, Won-Ho
    • Transactions of the Korean hydrogen and new energy society
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    • v.22 no.5
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    • pp.663-670
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    • 2011
  • Under a daily photoperiod of 14h light and 10h dark synchronization of cell cycle in Korean Cyanothece spp. strains and $Synechococcus$ sp. strain Miami BG043511 was analyzed as to be applicable to enhanced hydrogen production. For all strains peaks of double cell were observed during the light period of a daily cycle. Peaks of maximal cell size measured by a coulter counter appeared at the peak of double cells observed under light microscope reconfirming the synchronization of daily cell cycle. The cell cycle synchronization became weakened within two days when treated with continuous illumination. Rapid detection of the peak time of double cell percentage by coulter counters may contribute to quasi-realtime feedback control for efficient production of photobiological hydrogen by unicellular cyanobacterial strains.

Cell Search In Asynchronous W-CDMA System (비동기식 W-CDMA 시스템의 셀 탐색(Cell Search)에 관한연구)

  • 김강온;김병학;김철성
    • Proceedings of the IEEK Conference
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    • pp.325-328
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    • 2001
  • In this work, Cell search which is one of the important abilities of W-CDMA system in Reyleigh s fading channel is studied by using Cell Searcher of asynchronous IMT-2000 system(3GPP) and Cell - search simulation. For the methods of cell search to optimize codes, three stages are considered: 1) slot synchronization, 2) frame synchronization, and 3) scrambling code identification. It is found that key system parameters such as Primary Synchronization Channel (P-SCH), Secondary L Synchronization Channel(S-SCH), and Common Pilot Channel (CPCH) loading factor are optimized. It is noted that the smaller Optimal threshold value, the larger SNR of the received singnal. Therefore, It is important that the optimal threshold value is selected in the region of SNR

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Detecting cell cycle-regulated genes using Self-Organizing Maps with statistical Phase Synchronization (SOMPS) algorithm

  • Kim, Chang Sik;Tcha, Hong Joon;Bae, Cheol-Soo;Kim, Moon-Hwan
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.1 no.2
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    • pp.39-50
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    • 2008
  • Developing computational methods for identifying cell cycle-regulated genes has been one of important topics in systems biology. Most of previous methods consider the periodic characteristics of expression signals to identify the cell cycle-regulated genes. However, we assume that cell cycle-regulated genes are relatively active having relatively many interactions with each other based on the underlying cellular network. Thus, we are motivated to apply the theory of multivariate phase synchronization to the cell cycle expression analysis. In this study, we apply the method known as "Self-Organizing Maps with statistical Phase Synchronization (SOMPS)", which is the combination of self-organizing map and multivariate phase synchronization, producing several subsets of genes that are expected to have interactions with each other in their subset (Kim, 2008). Our evaluation experiments show that the SOMPS algorithm is able to detect cell cycle-regulated genes as much as one of recently reported method that performs better than most existing methods.

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A Study on Cell ID Detection Scheme Using Synchronization Signals for 5G NR System (5G NR 시스템을 위한 동기 신호를 이용한 cell ID 검출을 위한 방법 연구)

  • Ahn, Haesung;Cha, Eunyoung;Kim, Hyeongseok;Kim, Jeongchang
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.593-595
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    • 2020
  • 본 논문에서는 5G NR 시스템을 위한 동기 신호를 이용한 cell ID 검출 방법에 대한 성능을 비교하였다. 5G NR(fifth-generation new radio) 시스템의 송신기는 SS/PBCH (synchronization signal/physical broadcast channel) 블록을 송신하며, 수신기는 수신된 SS/PBCH 블록을 이용하여 주파수 및 타이밍 오프셋 (frequency and timing offset)을 추정 할 수 있으며, cell ID (cell identity)는 PSS (primary synchronization signal)와 SSS (secondary synchronization signal)를 통해 검출할 수 있다. 본 논문에서는 cell ID 를 검출할 수 있는 방법으로서 2-stage 디코딩 방법과 결합 최대우도 결정 규칙 (joint maximum-likelihood decision rule: joint ML) 디코딩 방법을 사용하였다. Joint ML 디코딩 방법은 2-stage 디코딩 방법에 비해 더 좋은 검출 성능을 보이지만, 복잡도 측면에서는 2-stage 디코딩 방법이 joint ML 디코딩 방법에 비해 더 낮은 복잡도를 갖는 것을 확인하였다.

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A Study of the Factors of Synchronization Model on Myocardial Cell Rhythms (심근세포의 동기리듬에 관한 공학적 연구)

  • 박민용
    • Journal of Biomedical Engineering Research
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    • v.5 no.1
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    • pp.33-38
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    • 1984
  • Biological rhythms are very important phenomena to generate, grow a living thing. However, the origin of rhythms are not disclosed completely until now. Eack myocardial cell has a natural rhythm of itself, and synchronization is happened when two cells are come in contact with each other. In this research, a simple synchronization model has been proposed and studied, refering to the physiological model. The changes of the synchronization rhythms in experimental results are compared with that of the model.

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The Traffic Control Mechanisms and Performance Analysis of Multimedia Synchronization Cell (멀티미디어 동기셀의 트래픽 제어 기법 및 성능 분석)

  • Jeon, Byeong-Ho;Kim, Tae-Gyun
    • The Transactions of the Korea Information Processing Society
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    • v.3 no.2
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    • pp.305-314
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    • 1996
  • In the paper, we divide the ATM cells generated by multimedia systems that want to transmit multimedia informations over B-ISDN into two categories:i)a media cell with a media information and ii) a synchronization cell with a synchronization information. We induce a media cell loss equation and a synchroni- zation cell loss equation based on probability distribution functions with on-off source as an input traffic model. In order to meet the requirements of real-time and integrity of multimedia informations, multimedia synchronization cells should provide the delay-sensitive and the loss-sensitive requirements. A traffic control mechanism needs to satisfy above requirements. According to the performance evaluation by a traffic control model simulation, we describe both spatial priority for minimizing the synchronization cell loss and temporal priority for reducing the synchronization cell delay must be applied simultaneously.

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Complexity Reduced CP Length Pre-decision Algorithm for SSS Detection at Initial Cell Searcher of 3GPP LTE Downlink System (3GPP LTE 하향링크 시스템의 초기 셀 탐색기 SSS 검출 시 복잡도 최소화를 위한 CP 길이 선 결정 알고리즘)

  • Kim, Young-Bum;Kim, Jong-Hun;Chang, Kyung-Hi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.9A
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    • pp.656-663
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    • 2009
  • In 3GPP LTE system downlink, PSS (primary synchronization signal) and SSS (secondary synchronization signal) sequences are used for initial cell search and synchronization. UE (user equipment) detects slot timing, frequency offset, and cell ID by using PSS. After that it should detect frame timing, cell group ID, and CP length by using SSS. But in 3GPP LTE, there are two kinds of CP length, so we should operate FFT twice. In this paper, to minimize SSS detection complexity in cell searcher, we propose a CP length pre-decision algorithm that reduces the arithmetical complexity by half at most, with negligible performance degradation.

A High-Speed Synchronization Method Robust to the Effect of Initial SFO in DRM Systems (DRM 시스템에서 초기 샘플링 주파수 옵셋의 영향에 강인한 고속 동기화 방식)

  • Kwon, Ki-Won;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.1A
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    • pp.73-81
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    • 2012
  • In this paper, we propose a high-speed synchronization method for Digital Radio Mondiale (DRM) receivers. In order to satisfy the high-speed synchronization requirement of DRM receivers, the proposed method eliminate the initial sampling frequency synchronization process in conventional synchronization methods. In the proposed method, sampling frequency tracking is performed after integer frequency synchronization and frame synchronization. Different correlation algorithms are applied to detect the first frame of the Orthogonal Frequency Division Multiplexing (OFDM) demodulation symbol with sampling frequency offset (SFO). A frame detection algorithm that is robust to SFO is selected based on the performance analysis and simulation. Simulation results show that the proposed method reduces the time spent for initial sampling frequency synchronization even if SFO is present in the DRM signal. In addition, it is verify that inter-cell differential correlation used between reference cells is roubst to the effect of initial SFO.