Fully open wireless basebands are unlikely if not (legally) impossible. Modern radio front ends have significant software control/definition from the baseband c

Fully open wireless basebands are unlikely if not (legally) impossible. Modern radio front ends have significant software control/definition from the baseband chipset/firmware. They'll happily run outside of regulated limits (ERP etc). The only reason they can get Part 22/15 licenses is because their firmwares are sold locked down and can't be adjusted outside of regulated limits. Anyone that gets halfway interested in trying to make an open baseband, necessitating a custom radio front end, gets quickly uninterested once they look at the development costs and then needing to get a license.