Locking period and unlocking or freezing period and unfreezing period

Organization Name (Required - If you are an Oracle Partner, please provide the organization you are logging the idea on behalf of):

Accenture

Description (Required):

We have large number of Business units and our closing period for pervious month starts from 1st of every month and go on till 5th or 6th of every month. We are opening current period on 1st itself but during closure period we want to restrict all user not to submit PPR for previous month but they can submit for current period. The question here is how to lock previous period during closure period and then close at the end of closure period. Please advise.