Adaptive coding and modulation for hybrid FSO/RF systems

Hybrid free space optical (FSO)/RF communication systems can provide high throughput short range “lastmile” connectivity. Since channel conditions are highly variable, adaptive symbol rate and modulation schemes are attractive for this application to make better use of available resources. This paper focuses on the information-theoretic analysis of such FSO/RF systems and introduces an adaptive communication scheme resulting in a capacity-approaching and seamless joint system. Numerical and simulation results give insight into the relation between adaptive parameters and system performance, and provide guidance for the design of a practical hybrid system.