Your question is pretty general. But let me try to answer it. You need to know basics of electromagnetic radiation. You should be able to understand characteristics of  base stations (transmitter power, losses in interconnections and passive elements, antenna gain, how antenna radiation pattern looks like (is it omni directional or directional antenna...)). Also you should be able to know which frequencies and power range can impact on health. Regarding simulations http://www.comsol.com/ can be usefull for simulation of radiation and propagation. Hope this was useful.