Nimal Ekanayake

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A novel method for evaluating the symbol error rate of M-ary CPSK signals received over Nakagami-w fading channels with equal-gain combining (EGC) is presented. The new method does not rely on the characteristic function of the sum of Nakagami random variables. The error rate of CPSK signals for L-channel diversity is expressed as a L-fold integral. The(More)
The amplified spontaneous emission (ASE) noise of optical amplifiers and nonlinear phase (NLP) noise generated due to interaction of ASE noise and Kerr nonlinearity are the two main sources of noise in optical fiber communications systems. This paper presents an analysis of the effects of ASE noise and NLP noise on the symbol error rate performance of M-ary(More)
This paper presents an investigation on the applicability of the Hermite series expansion to analytically determine the probability density function of the sum of independent random variables and its application to analysis of problems that arise in digital communications. The density function of the sum of random variables is expressed in the form of an(More)
The error probability of DPSK signals in Nakagami fading with EGC diversity reception is analyzed. The error rate is expressed as a (L + 1)-fold integral that contains only simple mathematical functions for L channel reception. The multiple integrals are easily evaluated with the Gauss-Legendre quadrature. Numerical values for the error rates of binary,(More)
An expression for the probability density function of the sum of independent and identically distributed random variables is derived. The new expression is in the form an infinite series containing Laguerre polynomials. This series is applied to determine the error rate performance for EGC diversity reception of CPSK signals in Nakagami fading channels. The(More)
We present the polarization dependence of the ultrafast photoionization for C<sup>+n</sup> (n &#x2264; 5) fragments from methane. The study extends from the strong field (C<sup>+</sup>, C<sup>+2</sup>) at 10<sup>14</sup> W/cm<sup>2</sup> to the ultrastrong field (C<sup>+5</sup>) at 10<sup>18</sup> W/cm<sup>2</sup>.
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