Hi-Z HI versus ZZ Top: The battle for the bands

Seeking answers to leading questions in modern astrophysics,
astronomers are (re)turning to the observational probe provided by the
lowest frequency radiation that reaches the surface of the Earth. Among
the hottest topics is the use of the 21cm line of hydrogen to study the
epoch of reionization over the redshift range ~20 to 6. Alas, the
relevant radio bands are in heavy demand to serve the communication
needs of modern societies thoughout the world. Have radio astronomy
technologies kept pace with communications technologies, and can we
hope to find signal processing methods that will allow us to see
through the foreground of radio interference, possibly by borrowing
from the "enemy"?  The answer is a resounding "maybe." And, the price
is likely to be high.