said by flashcore:You may have a 3G repeater in your building. It took forever for my previous employer to replace their AT&T Edge repeater with a 3G one. It behaved pretty much like you describe.
Its not only very un-reliable, it also does not work in most modern 10+ floor office buildings unless your near a window. Ive got a Nexus and can only get 1-2 bars of 3G at my office in the heart of Baltimore where they claim to have 100% 4G coverage. The second I walk outside I get 5 bars of 4G. Until they fix these major issues the LTE network it will continue to be worthless.