The performance analysis of multi-hop MIMO free space optical communications with space–time block codes over exponentiated Weibull fading channels

Abstract

The symbol error rate (SER) performance of decode-and-forward (DF) based multiple-input multiple-output (MIMO) multi-hop free-space optical (FSO) systems is investigated with space–time block coding (STBC) over the exponentiated Weibull (EW) fading channel. The moment generating function (MGF) and Gauss–Laguerre quadrature rule are adopted to derive the end-to-end (EE) analytical SER expressions for this considered FSO communication system. The SER performance is further studied under various hops, STBC schemes, and turbulence conditions detailly. In addition, the asymptotic EE SER expressions are obtained to evaluate the diversity orders. Results show that the SER performances of this FSO system under EW atmospheric turbulence distribution can be improved considerably by employing the STBC scheme, and the diversity order depends not only on the numbers of transmitting and receiving antennas, but also on the channel fading parameters. The SERs of EW distribution are compared with Lognormal (LN) and gamma–gamma (G–G) distributions in weak and strong turbulence atmosphere, respectively. We also verify these analytical results through Monte Carlo simulations. This work is beneficial to the design of FSO system.