Hi,
In GSM, Software tools like TCP from Ericsson is available for cell planning. Here map of the area with clutter and other details are fed and depending upon residential , commercial, urban or rural area, TCP creates a nominal plan giving location(coordinates) of sites to be installed for optimum capacity, coverage and performance. For each site, buildings for rooftops and plots for Greenfield are searched within a search radius. Rooftops are selected for an average antenna height of 20m i.e. from centre of the antenna down to ground level while greenfields are of different heights. Normally three antennae are installed for three sectors at 0/120/240 degrees.