• Title/Summary/Keyword: minimum received power

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Design of a Double-Faced Window Printed Antenna for Aircraft Applications (항공기용 양면 인쇄형 글래스 안테나 설계)

  • Byun, Gang-Il;Han, Wone-Keun;Choo, Ho-Sung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.2
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    • pp.131-139
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    • 2011
  • In this paper, we propose a double-faced window printed antenna for aircraft applications. The proposed antenna structure consists of a feeding line and a multi-loop radiator located on different sides of the window to use the limited given-area effectively. The proposed antenna is optimized by the genetic algorithm in conjunction with the FEKO EM simulator. The optimized antenna is built and installed on a 1/10 sized KUH-Surion mock-up and antenna performances such as the reflection coefficient and the radiation patterns are measured. The optimized antenna shows a half power matching bandwidth of about 33 % at 60 MHz and an average bore-sight gain of about -3.49 dBi. To verify the reception capability of the optimized antenna, we simulated the received power according to a flight scenario. The result confirms that the optimized antenna shows a minimum received power level above -60 dBm at a range of 200 km, which is similar to the pole antenna that is currently used as a FM voice antenna for KUH-Surion.

Pro-active Routing Selection and Maintenance Algorithms for Mobile Ad Hoc Network Environments (이동 Ad Hoc 네트워크 환경에서 사전 활성화 라우팅 선택과 관리유지 알고리즘)

  • Cho Young-Joo;Chung Il-Yong
    • Journal of Korea Multimedia Society
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    • v.9 no.5
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    • pp.606-614
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    • 2006
  • The conventional on-demand mobile ad hoc routing algorithms (DSR and AODV) initiate route discovery only after a path breaks, incurring a significant cost and time in detecting the disconnection and establishing a new route. In this theory, we investigate adding proposed pro-active route selection and maintenance to the conventional on-demand mobile ad hoc routing algorithms(DSR and AODV). The key idea is to be only considered likely to be a path break when the received packet power becomes close to the minimum critical power and to be generated the forewarning packet when the signal power of a received packet drops below a optimal threshold value. After generated the forewarning packet, the source node can initiate rout discovery in advance; potentially avoiding the disconnection altogether. Our extensive simulation study shows that the proposed advance-active route selection and maintenance algorithms outperforms the conventional on-demand routing protocol based on DSR and AODV in terms of packet delivery ratio, packet latency and overhead.

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Redundant Operation of a Parallel AC to DC Converter via a Serial Communication Bus

  • Kanthaphayao, Yutthana;Kamnarn, Uthen;Chunkag, Viboon
    • Journal of Power Electronics
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    • v.11 no.4
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    • pp.533-541
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    • 2011
  • The redundant operation of a parallel AC to DC converter via a serial communication bus is presented. The proposed system consists of three isolated CUK power factor correction modules. The controller for each converter is a dsPIC30F6010 microcontroller while a RS485 communication bus and the clock signal are used for synchronizing the data communication. The control strategy of the redundant operation relies on the communication of information among each of the modules, which communicate via a RS485 serial bus. This information is received from the communication checks of the converter module connected to the system to share the load current. Performance evaluations were conducted through experimentation on a three-module parallel-connected prototype, with a 578W load and a -48V dc output voltage. The proposed system has achieved the following: the current sharing is quite good, both the transient response and the steady state. The converter modules can perform the current sharing immediately, when a fault is found in another converter module. In addition, the transient response occurs in the system, and the output voltages are at their minimum overshoot and undershoot. Finally, the proposed system has a relatively simple implementation for the redundant operation.

The Conception & Fail-Mode Analysis of PTC Thermistor for Over-Current Protection (PST측면에서의 과전류 보호용PTC 소자의 개념 정립 및 Failure-Mode 분석)

  • 박준호
    • Proceedings of the Safety Management and Science Conference
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    • 2001.05a
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    • pp.67-75
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    • 2001
  • Circuitry to be connected to a Telecommunication Network consists of SELV CIRCUITS or TNV CIRCUITS. So International Standards, like as ITU-T Recommendation K.11, UL 1950, CSA C22.2 950 have been taken to reduce the risk that the Overvoltages from the power lines and from electrictraction lines, that may be received from the telecommunication network. Legal requirements may exist regarding permission to connect equipment having PTC components to a telecommunication network. Surge suppressors that bridge the insulation shall have a minimum d.c. sparkover voltage of 1.6 times the rated voltage or 1.6 times the upper voltage of the tared voltage range of the equipment. If left in place during electric strength testing of insulation, they shall not be damaged. In this work, The Conception & Fail-Mode Analysis of PTC components for Over-Current Protection is proposed. It guarantees the protection for PL Claim about this Subject.

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Reference Particles-based LTE Base Station Positioning

  • Cho, Seong Yun;Kwon, Jae Uk
    • Journal of Positioning, Navigation, and Timing
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    • v.10 no.3
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    • pp.207-214
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    • 2021
  • A new positioning technique for positioning of LTE base stations is proposed. The positioning information of the base station is absolutely necessary for model-based wireless positioning, and is required in some of the various merhodologies for estimating signals in an uncorrected area when construnting a database for fingerprinting-based positioning. Using the acquired location-based Reference Signal Received Power (RSRP) information to estimate the location of the base station, it is impossible with the existing trilateration methods. Therefore, in this paper, a method using reference particles is proposed. Particles are randomly generated in the application area, and signal propagation modeling is performed assuming that a base station is located in each particle. Based on this, the errors of measurements are calculated. The particle group with the minimum measurement errors is selected, the position of the base station is estimated through weighted summation, and the signal propagation model of the corresponding base station is built at the same time. The performance of the proposed technology is verified using data acquired in Seocho-dong, Seoul.

Optic Link Performances on EOM′s Biasing in Fiber-radio System (주파수 천이를 이용한 광무선 시스템에서 EOM의 바이어스 방식에 따른 광링크 성능 분석)

  • O, Se-Hyeok;Yang, Hun-Gi;Choe, Yeong-Wan
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.38 no.2
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    • pp.128-136
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    • 2001
  • This paper evaluates the performance of an optic link in a frequency conversion based fiber-radio system. The proposed link structure simplifies a BS(base station) via making the MMW(millimeter wave) optical pilot tone generated in the CS(control station) be used in the uplink as well as in the downlink. To acquire the optical pilot tone, an EOM(electro-optic modulator) in the CS is biased in three different ways, i.e., MAB(maximum bias), MIB(minimum bias), QB(quadrature bias). We, depending on the biasing of the EOM, evaluate the link performances in two cases; one is for constant laser source power and the other for constant received DC optical power at a PD(photo detector). Based on the simulation results on the downlink CNR and the uplink SFDR(spurious free dynamic range), we finally deduce the effective EOM biasing for each case.

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Effect of a cell loading on the soft handoff of a DS-CDMA cellular system (Cell loading이 D-CDMA 셀룰러 시스템의 소프트 핸드오프에 미치는 영향)

  • 김경민;김남수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.8A
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    • pp.1223-1230
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    • 2000
  • In this paper, we proposed a handoff decision method based on signal-to-interference ratio(SIR) of the pilot channel in order to perform a handoff more effectively and to complement disadvantages - deterioration quality of a call, decreasing capacity of the system, and wasting power of the mobile station - which is caused when handoff is performed by the classical method that execute a handoff based on received signal strength. Moreover, when we change that the minimum threshold, the cell loading which is defined active traffic channels to total traffic channels ratio, and the fraction of the transmit power from base station allocated to the pilot channel on the forward link of a DS-CDMA system, we analyzed mean numbers of handoff depending on hysteresis level during the mobile station moving from one base station to another base station.

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Implementation of a Real-time Frequency Non-selective Fading Channel Simulator Using a TMS320C542 Processor (TMS320C542 프로세서를 이용한 실시간 주파수 비선택성 페이딩 채널 시뮬레이터 구현)

  • 이준영;이찬길
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.8A
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    • pp.1187-1194
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    • 1999
  • In general wireless mobile channel is modeled as complex random processes having a narrowband spectrum. In this paper, a real-time feneration of fading signals using a DSP chip is described. Real-time simulator is designed so that simulation parameters such as mobile terminal speed, carrier frequency, power ratio of line-of-sight component versus multipath, and variance of received power can be chosen in the window. Design algorithms for the generation of ideal fading signals with a minimum DSP computation and trade-offs are investigated. The accuracy of the statistical characteristics is verified through the comparison of measured results with the theoretical prediction.

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Joint Detection Method for Non-orthogonal Multiple Access System Based on Linear Precoding and Serial Interference Cancellation

  • Li, Jianpo;Wang, Qiwei
    • Journal of Information Processing Systems
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    • v.17 no.5
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    • pp.933-946
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    • 2021
  • In the non-orthogonal multiple access (NOMA) system, multiple user signals on the single carrier are superimposed in a non-orthogonal manner, which results in the interference between non-orthogonal users and noise interference in the channel. To solve this problem, an improved algorithm combining regularized zero-forcing (RZF) precoding with minimum mean square error-serial interference cancellation (MMSE-SIC) detection is proposed. The algorithm uses RZF precoding combined with successive over-relaxation (SOR) method at the base station to preprocess the source signal, which can balance the effects of non-orthogonal inter-user interference and noise interference, and generate a precoded signal suitable for transmission in the channel. At the receiver, the MMSE-SIC detection algorithm is used to further eliminate the interference in the signal for the received superimposed signal, and reduce the calculation complexity through the QR decomposition of the matrix. The simulation results show that the proposed joint detection algorithm has good applicability to eliminate the interference of non-orthogonal users, and it has low complexity and fast convergence speed. Compared with other traditional method, the improved method has lower error rate under different signal-to-interference and noise ratio (SINR).

A Reinforcement Learning Framework for Autonomous Cell Activation and Customized Energy-Efficient Resource Allocation in C-RANs

  • Sun, Guolin;Boateng, Gordon Owusu;Huang, Hu;Jiang, Wei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.8
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    • pp.3821-3841
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    • 2019
  • Cloud radio access networks (C-RANs) have been regarded in recent times as a promising concept in future 5G technologies where all DSP processors are moved into a central base band unit (BBU) pool in the cloud, and distributed remote radio heads (RRHs) compress and forward received radio signals from mobile users to the BBUs through radio links. In such dynamic environment, automatic decision-making approaches, such as artificial intelligence based deep reinforcement learning (DRL), become imperative in designing new solutions. In this paper, we propose a generic framework of autonomous cell activation and customized physical resource allocation schemes for energy consumption and QoS optimization in wireless networks. We formulate the problem as fractional power control with bandwidth adaptation and full power control and bandwidth allocation models and set up a Q-learning model to satisfy the QoS requirements of users and to achieve low energy consumption with the minimum number of active RRHs under varying traffic demand and network densities. Extensive simulations are conducted to show the effectiveness of our proposed solution compared to existing schemes.