• Title, Summary, Keyword: repeater

Search Result 292, Processing Time 0.031 seconds

The study on the WiBro digital optic repeater design (휴대인터넷 디지털 광 중계기 설계에 대한 연구)

  • Ahn Jun-Bae;Ryoo Kyoo-Tae
    • 한국정보통신설비학회:학술대회논문집
    • /
    • /
    • pp.35-38
    • /
    • 2006
  • Using the repeaters is indispensable to WiBro services. Repeater types are distinguished by usage, output power and required performance. In the paper, we have studied on the WiBro digital optic repeater design which has excellent performance characteristic than any other repeaters. WiBro has specific characteristic on modulation method TDD(Time Division Duplex)/OFDMA(Orthogonal Frequency Division Multiple Access) so that it demands specified H/W to design WiBro repeater. Switching technique has been introduced because of TDD characteristic in each amplifier on the repeater. Time Advance technique has been considered because of OFDM characteristic among RAS(Radio Access Station) and repeater. In this paper, we have studied on these techniques to increase repeater cell coverage and distance between RAS and repeater.

  • PDF

A Visible Light Communication Repeater Using an LED Lamp (LED 조명등을 이용한 가시광통신 중계기)

  • Lee, Seong-Ho
    • Journal of Sensor Science and Technology
    • /
    • v.25 no.3
    • /
    • pp.189-195
    • /
    • 2016
  • In this paper, we newly introduce a visible light communication (VLC) repeater using the LED array in an LED lamp. The LED array is used for a light source in the repeater, which radiates light both for illumination and data transmission. A VLC repeater is made by adding some electronic circuits to the LED array including a photodetector, a demodulator, and a modulator. The repeater is installed on the ceiling of a room like a conventional LED lamp, receives the VLC signal from an arbitrary transmitter, recovers data, and radiates the signal to wide area in the room. We used a carrier frequency of 100 kHz for the uplink from a transmitter to the repeater, and 500 kHz for the downlink from the repeater to a receiver. The repeater is useful for increasing the transmission path to wide area over the obstacles that may exist between VLC transmitters and receivers.

The study on the LBS for WiBro repeater (휴대인터넷 중계기를 위한 LBS 적용 방안에 관한 연구)

  • Ahn Jun-Bae;Ryoo Kyoo-Tae
    • 한국정보통신설비학회:학술대회논문집
    • /
    • /
    • pp.53-56
    • /
    • 2006
  • WiBro service provider have made an effort to provide the subscriber's location and have deployed LBS system using cell-ID method. Cell-ID method has a location error problem if repeater is used on the other cell places at the same time. We introduce and analysis LMU(Location Measurement Unit) on the repeater fer location detection of subscriber which is serviced via the repeater. In this paper we propose the method using LMU on the repeater to avoid these location errors and to provide more exact location to the subscriber. we can conclude that the location error can be more exact at the building which uses repeater. It represents in which level the subscriber is serviced at the building.

  • PDF

An Indoor Positioning System Using Time-Synchronized Switching GPS Repeater (시각동기 스위칭 GPS 중계기를 이용한 실내측위 시스템)

  • Im Sung-Hyuck;Jee Gyu-In
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.12 no.8
    • /
    • pp.789-797
    • /
    • 2006
  • A new method for the GPS repeater based indoor positioning is proposed and its feasibility is verified by experiments in previous paper. But the problems how can identify switching GPS repeater's ID and when switching will be occurred are remained. To solve the problem faced with, we propose the time synchronized switching GPS repeater and the methods of the detection of switching time and the estimation of TDOA. First, switching GPS repeater retransmits the signals synchronized on GPS time, sequentially. Always, first switching time is synchronized with 1 PPS. Second, we formulate the detection of switching time and the estimation of TDOA and propose the various methods. No method is existed absolutely superior to others in any conditions but the method is existed superior to others in specific condition. Finally, feasibility of indoor positioning using time-synchronized switching GPS repeater is evaluated through experiments in anechoic chamber and general environment with multipath.

Performance Analysis of RF Repeater System using IP Antenna (IP 안테나를 이용한 RF 중계시스템의 성능분석)

  • Kang, Chang-Soo;Baek, Joo-Gi
    • 전자공학회논문지 IE
    • /
    • v.47 no.1
    • /
    • pp.34-40
    • /
    • 2010
  • Even if use ICS repeater in radio communication system, distance between Donor antenna and Service antenna though do much isolation degree must that shortcoming have. Proposed IP antenna to supplement this shortcoming in this paper. Result Doner antenna and isolation of Service antenna that measure through examination do 1.5m and when did direction 180 degree, Isolation confirmed that is measured 110dB. Confirmed that can unuse ICS repeater through this result and service by general RF repeater.

A Repeater-Assisted Indoor GPS Signal Acquisition and Tracking (중계기 도움방식의 실내 GPS 신호 획득 및 추적)

  • Song, Ha-Yeong;Im, Sung-Hyuck;Jee, Gyu-In
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.14 no.9
    • /
    • pp.963-968
    • /
    • 2008
  • A new method to deal with GPS indoor positioning by means of time synchronized switching GPS repeater has been developed by authors[1]. But the developed indoor positioning system has problems. Therefore, we proposed a method for indoor positioning using GNSS Repeater-Assisted. To solve the 3-dimensional user's position, the 4 or more retransmission antennas are needed in the previously proposed methods. If a GPS repeater periodically transmits the signal like as pseudollite, the information for assisting an acquisition and tracking can be informed to receiver. Then, the user position can be calculated using the induced weak signal. The advantage of the proposed algorithm is use of only 1 re-transmission antenna because the re-transmitted signal are not used for positioning but used for assisting an acquisition and tracking weak signals induced indoor. We analyze the propose algorithms through the experiment and performed the test of feasibility.

Low-Cost High-Performance TDD Synchronizer for WiBro RF Repeater

  • Seo, Young-Ho;Kim, Dong-Wook
    • ETRI Journal
    • /
    • v.32 no.4
    • /
    • pp.503-511
    • /
    • 2010
  • WiBro radio frequency (RF) repeater is used for solving the problem of partial shadow areas in the wireless communication field that uses time-division duplexing (TDD) mode. In this paper, a method to efficiently generate TDD signals for WiBro RF repeater is proposed and its digital circuit is implemented. A TDD signal is detected from RF signals transmitted/received to/from RF repeater and then inputted again into the RF repeater, so that it can operate normally. First, the envelope of downlink signals is detected and then clamped to extract the basic form of a TDD signal using an operational amplifier circuit. Next, the TDD signal is generated by restoring and filtering the shape which has been distorted by the wireless channel. The algorithm and system to acquire TDD signal are developed with a goal to have simple but powerful functions with as little cost as possible. The proposed method is implemented as an RF-digital integrated system and verified through the experiments under the same condition as actual WiBro service environment.

A Study of Repeater Effect Adjustment Algorithm in CDMA Indoor Positioning System (CDMA 기반의 실내 측위 시스템을 위한 중계기 보정 알고리즘에 관한 연구)

  • Choi, Hee-Dong;Kim, Sun-Mi;Choi, Jeong-Hee;Park, Yong-Wan
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.33 no.8C
    • /
    • pp.605-612
    • /
    • 2008
  • This paper researches the estimating location using repeater effect adjustment method in CDMA based system. Repeaters are commonly used by commercial and amateur radio operators to extend signals in the radio frequency range from one receiver to another. The repeater signals are increasing arrival time from base station to mobile station. So if we calculates the mobile station using repeater signals, the estimating position error is increased. However nobody researched about adjusting repeater effects. This paper proposes repeater effect adjustment algorithm. For adjusting repeater effects, we make the triangle using mobile station, reference base station and neighbor base station, and then detect the repeater effects using the triangle characteristic. The proposed method system showed the improved performance in estimating parameters and locating positions by computer simulations.

The Design of Smart Antenna Structures for RF Repeater (이동통신 중계기용 스마트 안테나 구조 설계)

  • Cho, Dae-Young;Kim, Kye-Won;Lee, Seung-Goo;Kim, Min-Sang;Kim, Kil-Yung;Park, Byeong-Hoon;Ko, Hak-Lim
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.14 no.2
    • /
    • pp.110-116
    • /
    • 2013
  • The amplification rate of a RF repeater is limited by the feedbacked signals from the same repeater. And an ICS (Interference Cancellation System) repeater has been developed to remove the feedbacked signals. The ICS repeater estimates the amplitudes and the phases of the feedbacked signals and removes the estimated feedback signals from the received input signal of the repeater. However, it requires lots of hardware complexity and this leads to the increase the cost of the repeater. Moreover, the ICS repeater can not solve the pilot pollution problems. To solve these problems, we have studied the implementation and adaptation of smart antenna system for RF repeaters. We have designed a smart antenna system with a switching beam structure in order to reduce the hardware and computational complexity. After analyzing the proposed smart antenna system, we found out that the amplification rate of the proposed repeater increases 23dB compare to the amplification rate of ICS repeater and the output SINR increases 6dB compare to the ICS repeater.

An analysis of field test results of terrestrial DTV on channel repeaters (지상파 DTV 동일채널 중계기 필드 테스트 결과 분석)

  • 조진호;권오형;안치득
    • Proceedings of the Korean Society of Broadcast Engineers Conference
    • /
    • /
    • pp.9-13
    • /
    • 2000
  • This paper represents analysis of field test results of terrestrial DTV on channel repeaters over Taejon city area. Two kind of on channel repeaters were tested. Non-regenerative repeater performs filtering, amplifying and re-transmit received main DTV signal. Regenerative repeater performs demodulation, modulation and amplifying and re-transmit received main DTV signal. The non-regenerative repeater threshold D/U ratio is about 10dB better than regenerative repeater's one.

  • PDF