Easy… ? Dimensionning a network simply by knowing the amount of traffic it will carry ? It can work on a small area ( city, a rural region) but it can’t work on mixed environment. In the latter case, you can’t now how many BTS and TRX you’ll need to provide enough coverage.
Let’s not forget that a network is primarily design to cover a certain surface of land (in sq. km). The national government will force the operator to cover a certain percentage of land.
Let’ take a stupid example : With one site, with 12 sectors and 12 TRX per sector, you can provide capacity for a whole province, but you will not be able to provide coverage.