They do not have to receive GPS, but it causes issues for e911 service if they do not. It has no impact on anything else, at least not the T-Mobile version.
The one I had, an AT&T Microcell, which was the only model offered by my cell provider, refused to work without a GPS signal.
Strange, because my AT&T Microcell didn't require a GPS signal. I kept it in the cabinet under the sink deep inside a large apartment building where there's no way it could get a GPS signal.
I haven't used since I moved a few years ago. Perhaps it's changed.
"After giving the MicroCell some power and ethernet, it will start blinking the 3G and GPS LEDs. Wait, what.. GPS? Yep. To limit the MicroCell from working outside of test markets (or out of the country too), it must get a GPS lock on your location. AT&T suggests this should take no longer than 90 minutes. It took me about 5 hours."
And this was the fundamental problem: there was absolutely no way to know if progress was being made or if it was going to run forever. It was literally a real-world Halting Problem.
