On the block error rate of FSO links with diversity over mixture gamma turbulence channels

Abstract

Recently, wireless communications started incorporating free space optical (FSO) systems to a large extent due to their high bandwidth and the low installation and operational cost. However, their performance deteriorates significantly due the weather conditions and the atmospheric phenomena. A very significant issue is the atmospheric turbulence which causes the scintillation effect and results in fast power fluctuations at the receiver which can be modelled through the appropriate stochastic models. A recently presented, accurate and with relatively simple mathematical form is the Mixture Gamma distribution. In order to improve the system's performance, various methods have been proposed and the receivers' diversity has proven to be a very effective one. In this work, for first time to the best of our knowledge, the average block error rate (BLER) performance of a terrestrial FSO communication link with receivers' diversity is estimated and new mathematical expressions are derived, for weak to strong turbulence channels with the Mixture Gamma distribution which emulate accurately the most of the well-known turbulence models. The derivation of the specific mathematical expressions is significant, especially for the modern FSO communication systems and networks with very high data rates, because if the BLER performance is known, the most efficient coding scheme can be chosen. Finally, using the new derived theoretical outcomes, the corresponding numerical results are presented for common FSO link parameters.