For other readers of this thread:
MS stands for Mobile Station. It's the technical term for "cell phone." :lol:
BTS stands for Base Transceiver Station. The BTS is the component of a mobile telephone network which provides the radio interface to the mobile stations.
chaperera, calculating the power requirements for the mobile stations won't do you any good -- because you can't control their power output. You get what the government regulators let the handset manufacturers provide.
For the BTS, power requirements are completely dependent upon the design of your DAS (Distributed Antenna System). Unless you have the right software, you are much better off relying on your BTS vendors to help you select the BTS model with the right power level to meet your needs.