Upgrade of oracle 10g (10.2.0.3) to 11g R2 (11.2.0.3)

Hi,

We have to urgently upgrade db 10g (10.2.0.3) to 11g R2 (11.2.0.3) since we are encountering bugs in 10g and oracle recommending to upgrade, please provide a simple and effective document which will cover upgrade to existing 10g db on same environment and should work with application. We are running Oracle E-Business Suit R12 (12.0.6), below are the details

Application Server:-

Linux 64bit (RHEL 4, release 6)

Oracle E-business suit R12 (12.0.6) Forms / Reports

Database Server:-

Linux 64bit (RHEL 4, release 6)

Oracle E-business suit R12 (12.0.6) Concurrent request

Oracle 10g (10.2.0.3) 

Discoverer Server:-

Linux 64bit (RHEL 4, release 6)

OracleBI Discoverer Version 10.1.2.2

Regards,

Javeed