Statistical Analysis of FSO Links Employing Multiple Transmitter/Receiver Strategy over Double-Generalized and Gamma-Gamma Fading Channel Using Different Modulation Techniques

摘要

Free space optical (FSO) communication links have recently received lot of attention as high bandwidth and cost-effective access technique. However, the transmission medium, i. e. atmosphere, itself is a major spoilsport factor as atmospheric turbulence may lead to fading. The legacy of spatial diversity techniques which have already proven their worth as effective mechanism to counter channel fading in radio links has also been extended to FSO links in this paper. A mathematical model to evaluate error rate performance of FSO links over strong turbulent conditions using gamma-gamma and double-generalized gamma channel model for different modulation techniques has also been included. It was observed that higher modulation techniques such as binary phase shift keying (BPSK) and differential phase shift keying (DPSK) allow superior error performance as compared to on-off keying (OOK) links, and this performance further enhances with incorporation of spatial diversity techniques. However, across different diversity options, explained in this paper, BPSK-MISO links were the best choice for turbulent conditions.