• Title/Summary/Keyword: Wrap-around simulation

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A Study on the Efficiency of CDMA Cellular System Simulation with Wrap Around Technique (Wrap Around 기법에 의한 CDMA 셀룰라 시스템 시뮬레이션 효율에 관한 연구)

  • 김호준
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.5A
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    • pp.276-283
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    • 2003
  • Most of CDMA system algorithm must be verified by simulating the cellular system consisted of many other tier cells. But it takes long time to simulate such a huge CDMA cellular system. In this paper, we propose an effective time saving simulation scheme based on wraparound technique. And we study that how our remaining cell interference compensation method works on calculating of the total interference, SIR, outage probability, and cell capacity. We made a conclusion that by using proposed scheme, we can get the same result of maximum configuration cells with only one tier real cells and that we can minimize the simulation time.

Implementation of Policing Algorithm in ATM network (ATM 망에서의 감시 알고리즘 구현)

  • 이요섭;권재우;이상길;최명렬
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.12C
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    • pp.181-189
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    • 2001
  • In this thesis, a policing algorithm is proposed, which is one of the traffic management function in ATM networks. The proposed algorithm minimizes CLR(Cell Loss patio) of high priority cells and solves burstiness problem of the traffic caused by multiplexing and demultiplexing process. The proposed algorithm has been implemented with VHDL and is divided into three parts, which are an input module, an UPC module, and an output module. In implementation of the UPC module\`s memory access, memory address is assigned according to VCI\`s LSB(Lowest Significant Byte) of ATM header for convenience. And the error of VSA operation from counter\`s wrap-around can be recovered by the proposed method. ANAM library 0.25 $\mu\textrm{m}$ and design compiler of Synopsys are used for synthesis of the algorithm and Synopsys VSS tool is used for VHDL simulation of it

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Development of CDMA Hierarchical Cellular Simulator using Object-Oriented-Program (객체지향프로그램을 이용한 CDMA 계층 셀 시뮬레이터 개발)

  • Kim, Ho-Joon
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.29 no.3
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    • pp.111-118
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    • 2006
  • This paper presents design and development of a simulator evaluates the performance of a hierarchical cellular system. The proposed hierarchical cellular simulator, consisting of macro, micro, and pico cells, applies the wrap-around technique to reduce simulation time. The simulator is implemented as object oriented class models by using the C++ language in a PC environment. The resulting application can evaluate the interference, SIR(Signal to Interference Ratio), and capacity of a hierarchical cellular system in various configurations. Moreover, it can be used in other applications such as power control, call admission control, hand over scheme.

Design of Gas-Injection Port of an Asymmetric Scroll Compressor for Heat Pump Systems (히트 펌프용 비대칭 스크롤 압축기의 가스 인젝션 포트 설계)

  • Kim, Yong-Hee;Kim, Hyun-Jin
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.6
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    • pp.300-306
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    • 2015
  • For an asymmetric scroll compressor for heat pump application, a numerical simulation was carried out to investigate the effects of injection port design on the compressor's performance under gas injection. To validate the simulation, the numerical results were compared with experimental results obtained from a scroll compressor with a base injection port design. There was good agreement between simulation and experimental results, with around a 1% difference in the injection mass flow rate when the injection pressure was below $12kgf/cm^2A$ for the heating mode. Various injection port angular positions were numerically tested to yield better injection performance. The largest improvement in heating capacity was obtained at angles of $240^{\circ}$ and $200^{\circ}$ inward from the scroll wrap end angle for low-temperature and standard heating conditions, respectively, while the maximum COP improvement was at $365^{\circ}$ and $280^{\circ}$, respectively. A considerable improvement in cooling capacity was also found at the injection port angle of $240^{\circ}$.

System-Level Simulation for Efficient Displacement of Base Station Antennas for CDMA Uplink System in Urban Microcells (도심 마이크로셀에서 CDMA 시스템을 위한 효율적인 기지국 배치를 위한 모의실험)

  • Min, Seung-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.5A
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    • pp.517-525
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    • 2008
  • In this paper, we cary out system level simulations to investigate the effect of cell shape(i.e., different base station displacements in the two directions defined by the street grid) on minimizing transmitter power, interference power, and blocking probability for CDMA system in urban microcellular environments. In urban microcell, path loss to the base station depends on the orientation of the street where the mobile is located. Interference from mobile stations to the base station in the reference cell is considered up to second tier. The wrap around method is used to include the second tier interference with realistic computational complexity without reducing the accuracy of interference calculations. The investigation shows that the transmitter power, interference power, and blocking probability in a cell can be reduced by proper selection of the efficient cell shape.

Research on the cable-driven endoscopic manipulator for fusion reactors

  • Guodong Qin;Yong Cheng;Aihong Ji;Hongtao Pan;Yang Yang;Zhixin Yao;Yuntao Song
    • Nuclear Engineering and Technology
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    • v.56 no.2
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    • pp.498-505
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    • 2024
  • In this paper, a cable-driven endoscopic manipulator (CEM) is designed for the Chinese latest compact fusion reactor. The whole CEM arm is more than 3000 mm long and includes end vision tools, an endoscopic manipulator/control system, a feeding system, a drag chain system, support systems, a neutron shield door, etc. It can cover a range of ±45° of the vacuum chamber by working in a wrap-around mode, etc., to meet the need for observation at any position and angle. By placing all drive motors in the end drive box via a cable drive, cooling, and radiation protection of the entire robot can be facilitated. To address the CEM motion control problem, a discrete trajectory tracking method is proposed. By restricting each joint of the CEM to the target curve through segmental fitting, the trajectory tracking control is completed. To avoid the joint rotation angle overrun, a joint limit rotation angle optimization method is proposed based on the equivalent rod length principle. Finally, the CEM simulation system is established. The rationality of the structure design and the effectiveness of the motion control algorithm are verified by the simulation.