Well with any wireless network(be it 2g,3g, 4g, Wifi, Wimax, even AMPS) the distance a signal can travel will depend on many possible things including geography (both natural and Urban geography) Urban zones are very difficult to meet capacity and coverage wise. trees, mountains and valleys and what else can drop that signal down below -96dBm. I work in a very old building in Center City Philadelphia and the signal is fine right outside but as soon as I walk inside the door signal begins to decrease. There's many variables in what will effect the distance a signal can travel.
Also the configuration of the site including how the sectors are setup and what power levels the sites are configured for.