Browsing by Author "Eyyuboğlu, Halil T."

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Beam wander of J (0)- and I (0)-Bessel Gaussian beams propagating in turbulent atmosphere
(Springer, 2010) Çil, Celal Zaim; Eyyuboğlu, Halil T.; Baykal, Yahya; Korotkova, Olga; Cai, Yangjian; 7688; 7812; Elektronik ve Haberleşme Mühendisliği; Elektrik-Elektronik Mühendisliği
Root mean square (rms) beam wander of J (0)-Bessel Gaussian and I (0)-Bessel Gaussian beams, normalized by the rms beam wander of the fundamental Gaussian beam, is evaluated in atmospheric turbulence. Our formulation is based on the first and the second statistical moments obtained from the Rytov series. It is found that after propagating in atmospheric turbulence, the collimated J (0)-Bessel Gaussian and the I (0)-Bessel Gaussian beams have smaller rms beam wander than that of the Gaussian beam, regardless of the choice of Bessel width parameter. However, the extent of such an advantage depends on the chosen width parameter, Gaussian source size, propagation distance and the wavelength. Focusing at finite distances of the considered beams causes the rms beam wander to decrease sharply at the propagation distances equal to the focusing parameter
MATLAB simulation of multiuser detection in CDMA
(World Acad Sci, 2005) Eyyuboğlu, Halil T.; 7688; Elektronik ve Haberleşme Mühendisliği
This paper describes the MATLAB simulation of multiuser detection in code division multiple access (CDMA). To reach low bit error rate (BER) levels within reasonable computation times, the method of importance sampling is utilized. Our design is based on the step by step practical implementation of matched filter (MF) detection, has therefore the flexibility of variations in all parameters of interest which are otherwise difficult to accommodate in a theoretical model. Our initial findings are compared and verified against theoretical predictions and against those available in the literature.