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[Keyword] subcarrier multiplexing(10hit)

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  • Frequency Shifted Optical SSB Modulation Scheme and Its Application to SCM Transmission

    Toshihito FUJIWARA  Koji KIKUSHIMA  

     
    LETTER-Fiber-Optic Transmission for Communications

      Vol:
    E91-B No:12
      Page(s):
    4003-4005

    We propose frequency shifted optical single sideband (OSSB), a novel OSSB modulation scheme. It uses a continuous wave to up-convert the source signal, and the signal and the continuous wave then undergo suppressed carrier OSSB modulation simultaneously. This scheme inherently has no unwanted sidebands, even if the suppressed carrier OSSB modulator is defective. Experiments of 12 GHz RF signal transmission confirm that it achieves 2.4 dB relaxation in chromatic dispersion power fading under the condition of 15 dB SSR.

  • Optical Beat Noise Reduction Using FM to AM Conversion of Injection-Locked FP-Laser Diode in Reflective SOA Based WDM/SCM-Passive Optical Networks

    Yong-Yuk WON  Hyuk-Choon KWON  Sang-Kook HAN  

     
    LETTER-Fiber-Optic Transmission for Communications

      Vol:
    E90-B No:10
      Page(s):
    2953-2956

    A new scheme for reducing optical beat interference noise in a reflective semiconductor optical amplifier based wavelength division multiplexed/subcarrier multiplexing -- passive optical network is proposed. This method uses an Fabry Perot laser locked by modulated lights from optical network units in a central office. As an experimental verification, it is reported that carrier to noise ratio is enhanced by 10 dB and power penalty is improved by 16 dB.

  • RoF Technologies for In-Building Wireless Systems

    Seongtaek HWANG  Hoon KIM  Byungjik KIM  Sung Kee KIM  Jaehoon LEE  Hanlim LEE  Yonggyoo KIM  Gyuwoong LEE  Sangho KIM  Yunje OH  

     
    INVITED PAPER

      Vol:
    E90-C No:2
      Page(s):
    345-350

    This paper reports on a fiber-optic system for in-building wireless communication/broadcast systems developed in Samsung Electronics. Our system delivers the third generation mobile system, satellite-digital multimedia broadcast, and wireless local access network services over a single strand of single-mode fiber or multi-mode fiber. We present the design issue and experimental results of the radio-over-fiber link.

  • Spatial Multiplexing in Optical Wireless MIMO Communications Over Indoor Environment

    Daisuke TAKASE  Tomoaki OHTSUKI  

     
    PAPER-Optical Wireless Communications

      Vol:
    E89-B No:4
      Page(s):
    1364-1371

    We propose optical wireless multiple-input multiple-output (OMIMO) communications to achieve high speed transmission with a compact transmitter and receiver. In OMIMO, by using zero forcing (ZF), minimum mean square error (MMSE) or other detection techniques, we can eliminate the interference from the other optical transmit antennas. In this paper, we employ ZF as the detection technique. We analyze the signal-to-interference-plus-noise ratio (SINR) and the bit error rate (BER) of the proposed OMIMO with a linear array and a square array of optical transmit and receive antennas, where we employ subcarrier multiplexing (SCM) for each optical transmit antenna. Note that the proposed OMIMO is applicable to other arrangements of optical transmit and receive antennas. We show that the proposed OMIMO system can realize MIMO multiplexing and achieve high speed transmission by correctly aligning the optical transmit and receive antennas and the transmitter semiangle.

  • Coax/Fiber Hybrid Access Network for Microcellular Personal Communication Systems

    Hanwook JUNG  Ozan K. TONGUZ  

     
    PAPER

      Vol:
    E79-B No:7
      Page(s):
    932-938

    A hybrid network architecture using subcarrier multiplexed optical fiber (SCMOL) and coaxial cable is proposed in this paper for the access link of future personal communication systems (PCS) between tiny passive radio base stations in microcells and remote central base stations. Results indicate that the required number of laser diodes, photodetectors and amount of fiber could be reduced by more than 4 times with the proposed hybrid access link compared to the point-to-point SCMOL link and the network cost would decrease proportionally.

  • A Centralized Control Microcell Radio System with Spectrum Delivery Switches

    Hirofumi ICHIKAWA  Mamoru OGASAWARA  

     
    PAPER-System and Network Matters

      Vol:
    E76-B No:9
      Page(s):
    1115-1121

    This paper presents a delivery mechanism using a spectrum delivery switch (SDS) in a microcell system. In our fiber-optic microcell systems, modulators, demodulators and spectrum delivery switches are installed in a central station. A spectrum delivery switch controls provide flexible dynamic channel assignment and functions as a hand over algorithm. This control method employs a TDMA time slot switch and a MODEM connection switch. The relation between blocking probability and offered traffic are described and computer simulation results are shown. The results indicate an improvement in this blocking probability over conventional systems.

  • Performance of FM Double Modulation for Subcarrier Optical Transmission

    Ryutaro OHMOTO  Hiroyuki OHTSUKA  

     
    PAPER-Equipment and Device Matters

      Vol:
    E76-B No:9
      Page(s):
    1152-1158

    This paper presents a potential FM double modulation technique for subcarrier optical transmission in order to improve the input dynamic range. The proposed theory of FM double modulation is presented. The BER performance and input dynamic range are shown theoretically and experimentally compared with conventional direct intensity modulation. It was found that the dynamic range could be experimentally improved by 20dB compared with the conventional method by using FM double modulation. The proposed technique achieved an input dynamic range of 60 dB even when using a commercial Fabri-Perot LD.

  • A Novel Optical Receiver for AM/QAM/FM Hybrid SCM Video Distribution Systems

    Satoyuki MATSUI  Ko-ichi SUTO  Koji KIKUSHIMA  Etsugo YONEDA  

     
    PAPER-Equipment and Device Matters

      Vol:
    E76-B No:9
      Page(s):
    1159-1168

    An optical receiver for hybrid SCM video distribution systems that distribute AM, QAM (quadrature amplitude modulation) and FM TV signals simultaneously is investigated. We propose a novel receiver configuration called the Frequency Division type Receiver (FDR) with consists of a photo detector, filter, and multiple preamplifiers. The receiver is compared with existing receivers in terms of optical sensitivity, distortion characteristics, and configuration simplicity. We clarify that the newly developed FDR type receiver is most suitable for hybrid SCM video distribution systems.

  • The Effects of Laser Phase Noise on Optical Coherent Coded Subcarrier Multiplexing System with Distributing Local Oscillator in Local Loop

    Tomoaki OHTSUKI  Iwao SASASE  Shinsaku MORI  

     
    PAPER-Fiber Optic Radio Links

      Vol:
    E76-C No:2
      Page(s):
    293-300

    In coherent optical subcarrier multiplexing (SCM) systems, the performance degradation of the system due to the phase noise of lasers restricts the maximum number of stations and channels that the system can serve. However, the effects of phase noise on the performance of the coherent SCM system with distributing Local Oscillator (LO) in local loop have not been analyzed. On the other hand, a limit on both the number of channels and stations can be effectively alleviated by using coding technique. In this paper, the effects of phase noise of lasers on the performance of frequency shift keying (FSK) SCM system with distributing LO in local loop are analyzed in terms of carrier-to-noise ratio (CNR) penalty. Second, the effects of Reed-Solomon (RS) coding on FSK SCM system with distributing LO in local loop are analyzed. It is shown that both the number of channels and stations can be increased by using coding technique.

  • Erbium-Doped Fiber Amplifiers for All-Fiber Video Distribution (AFVD) Systems

    Etsugo YONEDA  Ko-ichi SUTO  Koji KIKUSHIMA  Hisao YOSHINAGA  

     
    PAPER

      Vol:
    E75-B No:9
      Page(s):
    850-861

    This paper describes the impact of EDFAs on AM/FM FDM subcarrier multiplexing (SCM) all-fiber video distribution (AFVD) systems. As AM/FM hybrid system using EDFAs which can simultaneously distribute 11 AM-TV channels and 50 FM-TV channels is proposed and discussed. 4-stage amplifier-branch transmission experiments are introduced. The construction and performance of a newly designed 50 channel FM tuner are also presented.