Oracle Upgrade from 10.2.0.2. to 11.2.0.5

Hi

I have to Upgrade 10.2.0.2 Oracle server to 11.2.0.5 server

Can this be done in single step or would require first to be Upgraded to 10.2.0.5 and then to 11.2.0.5.

is there a way to do in single step.

Thanks and Regards

Tushar