Hi,supersonic
If you know the Erlang Cap. of BTS(ex.26Erl)and GOS(ex.1%)then you wil come to the No. of TrfCH or Simultanous user(By Erl-B table) and it comes to 36.Now if you assume 50mErl/Sub then capacity is(36CH/0.05Erl)720/sect/caarrier.
You have to remove %user for Data.