  The generation of a laser filament through clouds produces a shockwave which
displaces the small water droplets from the air to create a quasi-transparent
channel through which, information can be transmitted. We present a robust
method that utilizes the channel for free-space optical communication using
structured light beams coupled with a femtosecond filament. Vortex beams based
on their spatial profiles and non-diffractive characteristics are perfectly
suited to propagate around the filament. We have also developed a 4-bit
communication channel using these structured light beam. We introduce a method
dubbed segmented space division multiplexing. Our system demonstrates
resilience to noise and is unaffected by the filament. This method can improve
the scalability, robustness, and capacity of the free optical channel.
