You can set up a limited number of cellular network base stations. The obstacle is a muffled signal, and you must choose the station's optimal position to cover the maximum area.
It better, if you covers 100% of area, but if you're lazy, you can continue game with 97% covered, and return to level next time :)
There are 40 levels, first 5 is introductory, to understand game mechanics, last 3 is most harder. Good luck!