But satellites would also likely be controlled by entities subject to government pressure. (Perhaps a different government than the one in control of the local territory, but whichever, it won't always be in sympathy with the people on the ground.)

Tight-beam directional laser is an interesting idea, but does require a fair amount of advanced setup and calibration. And the base stations would still be vulnerable to detection if they're transmitting to something else that isn't tight-beam, like mobile handsets.

Perhaps balloon-based relay stations in the stratosphere, or solar-powered drones, which could be deployed without the expense of a satellite launch?

It is indeed a very hard problem.

EDIT: Further discussion, both on base stations and alternatives (packet radio, and the severe limitations thereof) here: http://news.ycombinator.com/item?id=2158111