“but I am not quite sure if I need to classify the BTSs according to areas where they are located!!!”
I would say yes, but I wont suggest how you run your planning tool but perhaps you might want to understand some reasons for classifying BTS located area e.g. how networks react to MSs for radio link management?
If you get time have a look at:
ETSI TR 101 639 V8.0.0 (2000-04)
Digital cellular telecommunications system (Phase 2+); Radio link management in hierarchical networks (GSM 05.22 version 8.0.0 Release 1999)
Read in the standard about Dwell Time (algorithm description created by France Telecom/CNET)
Also a useful guide: microcell coverage doesn’t go around corners where the microcell-BTS is to be wall-mounted.
Reading about terrain models can help when thinking about BTS installation and location.
One noteworthy model produced by British Telecommunications plc consisted of 10 categories [0-9]:
Category Description of the Terrain:
0 Rivers, lakes, and seas
1 Open rural areas (eg fields and heath-land with few trees)
2 Rural areas, similar to the above, but with wooded areas
3 Wooded or forested rural areas
4 Hilly or mountainous rural areas
5 Suburban areas, low-density dwellings, and modern industrial estates
6 Suburban areas, high-density dwellings (eg council estates)
7 Urban areas with buildings up to four storeys with gaps in-between
8 Higher density urban areas in which some buildings have more than four storeys
9 Dense urban areas in which most of the buildings have more than four stories and some can be classed as “skyscrapers”