Here in the Gulf it is different from Asian countries where you can get a phone with a postpaid plan.

Advise you to get all your electronics with you as its cheaper in Singapore than in Doha.

As for the internet, you will need to take a broadband connection (1mbps) is the standard here unlike Singapore (100mbps). Doha is still under going the fiber optic transition phase and only after that will the internet speed be upto international standards.