Toward an Optimal Combined FSO/RF System Via an Adaptive Bit Rate Control
In hybrid FSO/RF (Free Space Optics/Radio Frequency) systems, the FSO link is the primary link while the RF link is the secondary (backup) link. In current hybrid systems, once the FSO Signal to Noise Ratio (SNR) decreases above a preset threshold, the system switches from FSO to RF to maintain the communication connection. But this scenario does not provide maximum utilization of the available bandwidth in terms of spectrum efficiency. This paper proposes an adaptive FSO bit rate algorithm to maintain communication using the FSO link as long as its bit rate is greater than that can be offered by the RF, thus requiring no switching to the secondary link.