Performance of retro reflector-modulated links under weak turbulence

A method for the evaluation of performance of free space optical communications systems utilising modulating retro reflectors under weak turbulence is presented. The model considers the effects of system physical parameters, such as the modulating retro reflector effective size and receiver aperture diameter, on the bit-error rate (BER) and the capacity. Different spatial spectrums are used with the model and the effect of aperture averaging is evaluated directly from the normalised spatial covariance in each case. The log-normal distribution is adopted for the evaluation of BER in the weak fluctuation regime. Finally, for the first time the capacity of a system using modulated retro reflectors is calculated using a recently proposed closed-form expression. The model can be used as a performance metric in network routing algorithms.