• Title/Summary/Keyword: Sectorization

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Sectorization Algorithms of Adaptive Sector Antennas for CDMA Mobile Communication Systems (CDMA 이동통신 시스템을 위한 적응형 섹터 안테나의 섹터형성 알고리즘)

  • 이주형;오창헌;조성준
    • Proceedings of the IEEK Conference
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    • 2001.06a
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    • pp.41-44
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    • 2001
  • In this paper, we have investigated the adaptive sector antenna which can control the size and direction angle of sectors, and proposed the three sectorization algorithms which are based on distribution of users, distribution of codes and distribution of signal power, respectively. The BERs of each sectorization algorithms are compared through computer simulation. As results of the simulation, the sectorization algorithm based on signal power are better than the other in terms nf BER. We have simulated error performance the DS-CDMA/BPSK system with the antenna in AWGN, frequency non-selective Rayleigh fading and MAI channels.

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Vertical Sectorization Techniques in MISO Downlink Active Antenna Systems (MISO 하향 능동 안테나 시스템에서의 수직 섹터분할 기법)

  • Ahn, Minki;Eom, Subin;Lee, Inkyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.6
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    • pp.997-1004
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    • 2015
  • In this paper, we study vertical sectorization techniques in multiple-input single-output (MISO) downlink active antenna systems (AAS). In the AAS, antenna beam patterns can be adjusted in each sector and multiple vertical beams can form the vertical sectorization. Since an exhaustive search based vertical sectorization algorithm requires high computational complexity to find the optimal tilt angles, we propose two vertical sectorization algorithms to reduce the complexity. First, we provide an asymptotic sum rate based algorithm which utilizes a large system approximation of the average sum rate based on the random matrix theory. Next, by using the result in the single sector transmission, the single sector based algorithm is proposed. In the simulation results, we confirm that the proposed algorithms are close to the performance of the exhaustive search algorithm with much reduced complexity.

Biological function of CpSlt2, an ortholog of the cell wall integrity (CWI) MAPK of Saccharomyces cerevisiae, in the chestnut blight fungus Cryphonectria parasitica

  • So, Kum-Kang;Ko, Yo-Han;Chun, Jeesun;Kim, Jung-Mi;Kim, Dae-Hyuk
    • 한국균학회소식:학술대회논문집
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    • 2018.05a
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    • pp.11-11
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    • 2018
  • Cryphonectria parasitica, chestnut blight fungus, has a characteristic of decreasing pathogenicity when infected with Cryphonectria hypovirus 1. C. parasitica is known to be one of the most representative model systems used to observe the interaction between viruses, plants and fungi. The mitogen-activated protein kinase (MAPK) pathway, which is well conserved in various organisms ranging from yeast to humans, functions in relaying phosphorylation-dependent signals within MAPK cascades to diverse cellular functions involved in the regulation of pheromone, cell wall integrity, and osmotolerance in filamentous fungi. Several genes in the MAPK pathway were revealed to be regulated by hypovirus, or to be involved in pathogenicity in C. parasitica. Among these pathways, the CWI pathway has aroused interest because CpBck1, an ortholog of yeast Bck1 (a CWI MAPKKK), was previously reported to be involved in cell wall integrity and sectorization. Interestingly, sporadic sectorization was observed in the CpBck1 mutant and sectored phenotypes were stably inherited in the progeny that were successively transferred from sectored mycelia. In this study, we analyzed the biological function of CpSlt2, downstream gene of CpBck1, to confirm whether the sectorization phenomenon occurred in the specific single gene or cell wall integrity (CWI) pathway. As results, the CpSlt2-null mutant exhibited marked changes in colonial growth, near absence of conidiation and aerial hyphae, abnormal pigmentation, CWI-related phenotypic defects, and dramatically impaired virulence. As cultivation of the mutant strains progressed, the majority of the colonies showed sporadic sectorization and mycelia from the sectored area stably maintained the sectored phenotype. These results suggest that the unique sectorization is CWI pathway-specific, though the components in the same CWI pathway have common and specific functions.

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Comparative Transcriptomic Analysis of MAPK-Mediated Regulation of Sectorization in Cryphonectria parasitica

  • Chun, Jeesun;So, Kum-Kang;Ko, Yo-Han;Kim, Jung-Mi;Kim, Dae-Hyuk
    • Molecules and Cells
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    • v.42 no.4
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    • pp.363-375
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    • 2019
  • Fungal sectorization is a complex trait that is still not fully understood. The unique phenotypic changes in sporadic sectorization in mutants of CpBck1, a mitogen-activated protein kinase kinase kinase (MAPKKK) gene, and CpSlt2, a mitogen-activated protein kinase (MAPK) gene, in the cell wall integrity pathway of the chestnut blight fungus Cryphonectria parasitica have been previously studied. Although several environmental and physiological factors cause this sectoring phenotype, genetic variants can also impact this complex morphogenesis. Therefore, RNA sequencing analysis was employed to identify candidate genes associated with sectorization traits and understand the genetic mechanism of this phenotype. Transcriptomic analysis of CpBck1 and CpSlt2 mutants and their sectored progeny strains revealed a number of differentially expressed genes (DEGs) related to various cellular processes. Approximately 70% of DEGs were common between the wild-type and each of CpBck1 and CpSlt2 mutants, indicating that CpBck1 and CpSlt2 are components of the same MAPK pathway, but each component governs specific sets of genes. Functional description of the DEGs between the parental mutants and their sectored progenies revealed several key pathways, including the biosynthesis of secondary metabolites, translation, amino acid metabolism, and carbohydrate metabolism; among these, pathways for secondary metabolism and translation appeared to be the most common pathway. The results of this comparative study provide a better understanding of the genetic regulation of sector formation and suggest that complex several regulatory pathways result in interplays between secondary metabolites and morphogenesis.

Performance Analysis and Optimum Beam Combination for Vertical Sectorization in LTE Systems (LTE 시스템에서 수직적 섹터구분 방식의 성능 분석 및 최적 빔 조합 도출)

  • Suh, Pan-Kyu;Park, Chang-Min;Cho, Gyu Seong;Park, Haesung;Kim, Duk Kyung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.3
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    • pp.158-160
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    • 2014
  • Recently, owing to the development of active array antenna techniques, various sector beams can be applied to the LTE systems with vertical sectorization. In this paper, we evaluate the system performance and suggest an optimum beam combination and parameters by using a system level simulator

Achievable Sum Rate Enhancement by Sectorization for Dirty Paper Coding Aided Multihop Cellular Networks (Dirty Paper Coding을 이용한 다중 도약 셀룰러 네트워크에서 Sectorization을 통한 전송률 향상)

  • Park, Sung-Soo;Song, Hyung-Joon;Lim, Sung-Mook;You, Cheol-Woo;Hong, Dae-Sik
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.241-242
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    • 2008
  • This paper proposes a sectorization and exclusive subcarrier allocation technique for dirty paper coding (DPC) aided orthogonal frequency division multiple access (OFDMA) multihop cellular networks. Simulation result shows that the proposed technique significantly increases the achievable sum rate compared to the conventional mobile station selection approach.

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Microcell Sectorization for Channel Management in a PCS Network by Tabu Search (광마이크로셀 이동통신망에서의 채널관리를 위한 동적 섹터결정)

  • Lee, Cha-Young;Yoon, Jung-Hoon
    • Journal of Korean Institute of Industrial Engineers
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    • v.26 no.2
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    • pp.155-164
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    • 2000
  • Recently Fiber-optic Micro-cellular Wireless Network is considered to solve frequent handoffs and local traffic unbalance in microcellular systems. In this system, central station which is connected to several microcells by optical fiber manages the channels. We propose an efficient sectorization algorithm which dynamically clusters the microcells to minimize the blocked and handoff calls and to balance the traffic loads in each cell. The problem is formulated as an integer linear programming. The objective is to minimize the blocked and handoff calls. To solve this real time sectorization problem the Tabu Search is considered. In the tabu search intensification by Swap and Delete-then-Add (DTA) moves is implemented by short-term memory embodied by two tabu lists. Diversification is considered to investigate proper microcells to change their sectors. Computational results show that the proposed algorithm is highly effective. The solution is almost near the optimal solution and the computation time of the search is considerably reduced compared to the optimal procedure.

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Multiple Ant Colony System (MACS) for the Dynamic Sectorization in Microcellular System (마이크로셀룰러 시스템에서 동적 섹터결정을 위한 MACS)

  • Kim, Sung-Soo;Hong, Soon-Jung;Ahn, Seung-Bum
    • IE interfaces
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    • v.19 no.1
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    • pp.1-8
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    • 2006
  • The mobile communication network has to offer good quality of services (QoS), high capacity, and more coverage at a lower cost. However, with the increase of cellular user, the shortage of capacity due to unbalanced call distribution and lack of QoS are common. This paper deals with dynamic sectorization for efficient resource management to solve load unbalancing among microcells in CDMA (Code Division Multiple Access) microcellular system. Dynamic load balancing can be effected by grouping micro-cells properly and grouping can be developed through a routing mechanism. Therefore, we use ants and their routes to choose the optimum grouping of micro-cells into sectors using Multiple Ant Colony System (MACS)in this paper.

Wideband DS/CDMA system capacity analysis impacted by the man-made noise and imperfect sectorization (불완전 섹터화 및 인공잡음의 영향에 의한 광대역 DS/CDMA시스템의 용량 분석)

  • Kim, Hae-Ki;Kim, Nam
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.65-68
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    • 1999
  • In this paper the Wideband DS/CDMA system capacity variation is analyzed by the impact of imperfect sectorization and man-made noise, which is more predominant in urban area than thermal noise. In general man-made noise is increasing as the electronic machines are increasing nowadays. It shows that user capacity and cell radius variation are much sensitive by the man-made noise.

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