Elektrik Elektronik Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/411

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Author: search.filters.author.Gokce, Muhsin CanerPublisher: search.filters.publisher.Elsevier Science Bv

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Now showing 1 - 4 of 4
  • Article
    Citation - WoS: 12
    Citation - Scopus: 11
    Error Performance of Optical Wireless Communication Systems Exercising Bpsk Subcarrier Intensity Modulation in Non-Kolmogorov Turbulent Atmosphere
    (Elsevier Science Bv, 2019) Baykal, Yahya; Gokce, Muhsin Caner; Ata, Yalcin
    Subcarrier intensity modulation (SIM) scheme is preferred due to efficient bandwidth usage superiority over other modulation techniques such as on-off keying (OOK), pulse position modulation (PPM). In this paper, we investigate the bit error rate (BER) performance of optical wireless communication (OWC) system using binary phase shift keying (BPSK) SIM in non-Kolmogorov turbulent atmosphere. We pay attention to the weak turbulence conditions by using Rytov approximation and considering that the receiver is a PIN photodetector. Propagating beam type is Gaussian. It is seen that BER performance of the BPSK SIM OWC is significantly affected from non-Kolmogorov power law exponent, load resistor, responsivity of the PIN photodetector, bandwidth, beam source size, turbulence strength and noise factor.
  • Article
    Citation - WoS: 32
    Citation - Scopus: 40
    Performance Analysis of M-Ary Pulse Position Modulation in Strong Oceanic Turbulence
    (Elsevier Science Bv, 2018) Baykal, Yahya; Ata, Yalcin; Gokce, Muhsin Caner
    In this paper, we consider an underwater wireless optical communication (UWOC) system which consists of an M-ary pulse position modulated (PPM) Gaussian optical beam at the transmitter and an avalanche photodiode (APD) at the receiver. In strong oceanic turbulence, we aimed at investigating the system performance in terms of bit error rate (BER) by the help of gamma-gamma channel model. For this purpose, the average power and the aperture averaged scintillation at the finite sized detector are derived by using the extended Huygens-Fresnel principle and the asymptotic Rytov theory, respectively. BER variations are examined versus the average APD gain, modulation order, bit rate as well as the oceanic turbulence parameters, i.e., the rate of dissipation of kinetic energy per unit mass of fluid, the rate of dissipation of mean-squared temperature and the ratio of temperature to salinity contributions to the refractive index spectrum.
  • Article
    Citation - WoS: 36
    Citation - Scopus: 41
    Aperture Averaging in Strong Oceanic Turbulence
    (Elsevier Science Bv, 2018) Baykal, Yahya; Gokce, Muhsin Caner
    Receiver aperture averaging technique is employed in underwater wireless optical communication (UWOC) systems to mitigate the effects of oceanic turbulence, thus to improve the system performance. The irradiance flux variance is a measure of the intensity fluctuations on a lens of the receiver aperture. Using the modified Rytov theory which uses the small-scale and large-scale spatial filters, and our previously presented expression that shows the atmospheric structure constant in terms of oceanic turbulence parameters, we evaluate the irradiance flux variance and the aperture averaging factor of a spherical wave in strong oceanic turbulence. Irradiance flux variance variations are examined versus the oceanic turbulence parameters and the receiver aperture diameter are examined in strong oceanic turbulence. Also, the effect of the receiver aperture diameter on the aperture averaging factor is presented in strong oceanic turbulence. (C) 2017 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 71
    Citation - Scopus: 82
    Aperture Averaging and Ber for Gaussian Beam in Underwater Oceanic Turbulence
    (Elsevier Science Bv, 2018) Baykal, Yahya; Gokce, Muhsin Caner
    In an underwater wireless optical communication (UWOC) link, power fluctuations over finite-sized collecting lens are investigated for a horizontally propagating Gaussian beam wave. The power scintillation index, also known as the irradiance flux variance, for the received irradiance is evaluated in weak oceanic turbulence by using the Rytov method. This lets us further quantify the associated performance indicators, namely, the aperture averaging factor and the average bit-error rate (<BER>). The effects on the UWOC link performance of the oceanic turbulence parameters, i.e., the rate of dissipation of kinetic energy per unit mass of fluid, the rate of dissipation of mean-squared temperature, Kolmogorov microscale, the ratio of temperature to salinity contributions to the refractive index spectrum as well as system parameters, i.e., the receiver aperture diameter, Gaussian source size, laser wavelength and the link distance are investigated. (c) 2017 Elsevier B.V. All rights reserved.