Many towns and cities have been burned by spending millions on a proprietary system only to discover they can't talk to the next town over.
It would be nice if the DHS actually did something useful and put an end to that kind of crap.
This article http://www.americanprogress.org/issues/2005/09/b1029179.html from 2005 stresses the importance ans suggests using WiFi. Maybe. But the most important aspect is "one digital protocol to rule them all", no matter what band you're on.
Mater artium necessitas. [Necessity is the mother of invention].