An Implementation of Real Time Testbed of Cognitive Switch for Multi-user FSOC Link

Abstract

Free-space optical communication (FSOC) has been a popular alternative for radio frequency communication technology. Multiplicity and atmospheric turbulence are known to introduce fluctuations to FSOC link performance. Multiple-link FSOC performance can be simulated, implemented, and evaluated using a testbed. Experimental results indicate the feasibility of using a testbed for obtaining real-time signal comparison, user detection, and cognitive switching. This thesis presents a real-time, correlation-based methodology for signal comparison that can be used for detecting the number of communicating users and manipulating channels to isolate signals from mixed sources. The proposed methodology was experimentally validated using six approaches: 1) signal similarity by cosine similarity; 2) signal similarity by cross-correlation; 3) peak detection; 4) threshold determination; 5) real-time signal alignment; and 6) signal isolation.