Hybrid FSO/RF System Using Intelligent Power Control and Link Switching

Free Space Optical (FSO) communication is promising to provide a wireless connection of tens to hundreds of gigabit capacity. Despite of many advantages, FSO link is sensitive to weather conditions and atmospheric turbulence. To offset these limitations, using Radio Frequency (RF) link as a backup link is a wise choice and thus hybrid FSO/RF system gains wider attention. Research on link switching is of great importance as a key technology in hybrid FSO/RF system. It is well known that link switching is closely related to the Received Signal Strength Indication (RSSI). In this letter, by combining power control and link switching using Recurrent Neural Networks (RNN) to predict RSSI, we propose an intelligent power control and link switching scheme to enhance transmission effectiveness in hybrid FSO/RF system. We set up a testbed of hybrid FSO/RF system and experimentally validate the proposed scheme. Experimental results demonstrate that the proposed scheme can forecast the trend of RSSI accurately and the power control strategy can effectively improve transmission quality of FSO link by reducing the frequency of switching.