Gravity waves are way too hard to detect and generate to be used for communication. The waves we can just barely detect too 8 solar masses worth of energy to generate.
Remember that that 8 solar mass gravity wave source is potentially 100’s millions of light years away. A sci-fi author could conjure up a ‘portable box’ containing a couple of orbiting micro-scopic black holes in a box to generate gravity wave signals someone somewhere in the solar system could pick up with a portable LIGO device. Consider this comment a patent on the idea :-)
And people complained about next door's aerial farm!