  In this paper we propose a simulation method using numerical integration, and
develop a closed-form link loss model for physical layer channel
characterization for non-line of sight (NLOS) ultraviolet (UV) communication
systems. The impulse response of the channel is calculated by assuming both
uniform and Gaussian profiles for transmitted beams and different geometries.
The results are compared with previously published results. The accuracy of the
integration approach is compared to the Monte Carlo simulation. Then the path
loss using the simulation method and the suggested closed-form expression are
presented for different link geometries. The accuracies are evaluated and
compared to the results obtained using other methods.
